* [PATCH] zswap: dynamic pool creation
@ 2015-06-04 12:02 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-04 12:02 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: linux-mm, linux-kernel, Dan Streetman
Add dynamic creation of pools. Move the static crypto compression
per-cpu transforms into each pool. Add a pointer to zswap_entry to
the pool it's in.
This is required by a separate patch which enables changing the
zswap zpool and compressor params at runtime.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
---
mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 408 insertions(+), 142 deletions(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index 2d5727b..fc93770 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
static struct zpool *zswap_pool;
/*********************************
-* compression functions
+* data structures
**********************************/
-/* per-cpu compression transforms */
-static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
-enum comp_op {
- ZSWAP_COMPOP_COMPRESS,
- ZSWAP_COMPOP_DECOMPRESS
+struct zswap_pool {
+ struct zpool *zpool;
+ struct kref kref;
+ struct list_head list;
+ struct rcu_head rcu_head;
+ struct notifier_block notifier;
+ char tfm_name[CRYPTO_MAX_ALG_NAME];
+ struct crypto_comp * __percpu *tfm;
};
-static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
- u8 *dst, unsigned int *dlen)
-{
- struct crypto_comp *tfm;
- int ret;
-
- tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
- switch (op) {
- case ZSWAP_COMPOP_COMPRESS:
- ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
- break;
- case ZSWAP_COMPOP_DECOMPRESS:
- ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
- break;
- default:
- ret = -EINVAL;
- }
-
- put_cpu();
- return ret;
-}
-
-static int __init zswap_comp_init(void)
-{
- if (!crypto_has_comp(zswap_compressor, 0, 0)) {
- pr_info("%s compressor not available\n", zswap_compressor);
- /* fall back to default compressor */
- zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
- if (!crypto_has_comp(zswap_compressor, 0, 0))
- /* can't even load the default compressor */
- return -ENODEV;
- }
- pr_info("using %s compressor\n", zswap_compressor);
-
- /* alloc percpu transforms */
- zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
- if (!zswap_comp_pcpu_tfms)
- return -ENOMEM;
- return 0;
-}
-
-static void __init zswap_comp_exit(void)
-{
- /* free percpu transforms */
- free_percpu(zswap_comp_pcpu_tfms);
-}
-
-/*********************************
-* data structures
-**********************************/
/*
* struct zswap_entry
*
@@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
* page within zswap.
*
* rbnode - links the entry into red-black tree for the appropriate swap type
+ * offset - the swap offset for the entry. Index into the red-black tree.
* refcount - the number of outstanding reference to the entry. This is needed
* to protect against premature freeing of the entry by code
* concurrent calls to load, invalidate, and writeback. The lock
* for the zswap_tree structure that contains the entry must
* be held while changing the refcount. Since the lock must
* be held, there is no reason to also make refcount atomic.
- * offset - the swap offset for the entry. Index into the red-black tree.
- * handle - zpool allocation handle that stores the compressed page data
* length - the length in bytes of the compressed page data. Needed during
* decompression
+ * pool - the zswap_pool the entry's data is in
+ * handle - zpool allocation handle that stores the compressed page data
*/
struct zswap_entry {
struct rb_node rbnode;
pgoff_t offset;
int refcount;
unsigned int length;
+ struct zswap_pool *pool;
unsigned long handle;
};
@@ -201,6 +156,44 @@ struct zswap_tree {
static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
+/* RCU-protected iteration */
+static LIST_HEAD(zswap_pools);
+/* protects zswap_pools list modification */
+static DEFINE_SPINLOCK(zswap_pools_lock);
+
+/*********************************
+* helpers and fwd declarations
+**********************************/
+
+#define zswap_pool_debug(msg, p) \
+ pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
+ zpool_get_type((p)->zpool))
+
+static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
+static int zswap_pool_get(struct zswap_pool *pool);
+static void zswap_pool_put(struct zswap_pool *pool);
+
+static bool zswap_is_full(void)
+{
+ return totalram_pages * zswap_max_pool_percent / 100 <
+ DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
+}
+
+static void zswap_update_total_size(void)
+{
+ struct zswap_pool *pool;
+ u64 total = 0;
+
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(pool, &zswap_pools, list)
+ total += zpool_get_total_size(pool->zpool);
+
+ rcu_read_unlock();
+
+ zswap_pool_total_size = total;
+}
+
/*********************************
* zswap entry functions
**********************************/
@@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
*/
static void zswap_free_entry(struct zswap_entry *entry)
{
- zpool_free(zswap_pool, entry->handle);
+ zpool_free(entry->pool->zpool, entry->handle);
+ zswap_pool_put(entry->pool);
zswap_entry_cache_free(entry);
atomic_dec(&zswap_stored_pages);
- zswap_pool_total_size = zpool_get_total_size(zswap_pool);
+ zswap_update_total_size();
}
/* caller must hold the tree lock */
@@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
**********************************/
static DEFINE_PER_CPU(u8 *, zswap_dstmem);
-static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
+static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
{
- struct crypto_comp *tfm;
u8 *dst;
switch (action) {
case CPU_UP_PREPARE:
- tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
- if (IS_ERR(tfm)) {
- pr_err("can't allocate compressor transform\n");
- return NOTIFY_BAD;
- }
- *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
if (!dst) {
pr_err("can't allocate compressor buffer\n");
- crypto_free_comp(tfm);
- *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
return NOTIFY_BAD;
}
per_cpu(zswap_dstmem, cpu) = dst;
break;
case CPU_DEAD:
case CPU_UP_CANCELED:
- tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
- if (tfm) {
- crypto_free_comp(tfm);
- *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
- }
dst = per_cpu(zswap_dstmem, cpu);
kfree(dst);
per_cpu(zswap_dstmem, cpu) = NULL;
@@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
return NOTIFY_OK;
}
-static int zswap_cpu_notifier(struct notifier_block *nb,
- unsigned long action, void *pcpu)
+static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
+ unsigned long action, void *pcpu)
{
- unsigned long cpu = (unsigned long)pcpu;
- return __zswap_cpu_notifier(action, cpu);
+ return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
}
-static struct notifier_block zswap_cpu_notifier_block = {
- .notifier_call = zswap_cpu_notifier
+static struct notifier_block zswap_dstmem_notifier = {
+ .notifier_call = zswap_cpu_dstmem_notifier,
};
-static int __init zswap_cpu_init(void)
+static int __init zswap_cpu_dstmem_init(void)
{
unsigned long cpu;
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
- if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
+ if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
+ NOTIFY_BAD)
goto cleanup;
- __register_cpu_notifier(&zswap_cpu_notifier_block);
+ __register_cpu_notifier(&zswap_dstmem_notifier);
cpu_notifier_register_done();
return 0;
cleanup:
for_each_online_cpu(cpu)
- __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
+ __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
cpu_notifier_register_done();
return -ENOMEM;
}
+static void zswap_cpu_dstmem_destroy(void)
+{
+ unsigned long cpu;
+
+ cpu_notifier_register_begin();
+ for_each_online_cpu(cpu)
+ __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
+ __unregister_cpu_notifier(&zswap_dstmem_notifier);
+ cpu_notifier_register_done();
+}
+
+static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
+ unsigned long action, unsigned long cpu)
+{
+ struct crypto_comp *tfm;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
+ break;
+ tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
+ if (IS_ERR_OR_NULL(tfm)) {
+ pr_err("could not alloc crypto comp %s : %ld\n",
+ pool->tfm_name, PTR_ERR(tfm));
+ return NOTIFY_BAD;
+ }
+ *per_cpu_ptr(pool->tfm, cpu) = tfm;
+ break;
+ case CPU_DEAD:
+ case CPU_UP_CANCELED:
+ tfm = *per_cpu_ptr(pool->tfm, cpu);
+ if (!IS_ERR_OR_NULL(tfm))
+ crypto_free_comp(tfm);
+ *per_cpu_ptr(pool->tfm, cpu) = NULL;
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static int zswap_cpu_comp_notifier(struct notifier_block *nb,
+ unsigned long action, void *pcpu)
+{
+ unsigned long cpu = (unsigned long)pcpu;
+ struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
+
+ return __zswap_cpu_comp_notifier(pool, action, cpu);
+}
+
+static int zswap_cpu_comp_init(struct zswap_pool *pool)
+{
+ unsigned long cpu;
+
+ memset(&pool->notifier, 0, sizeof(pool->notifier));
+ pool->notifier.notifier_call = zswap_cpu_comp_notifier;
+
+ cpu_notifier_register_begin();
+ for_each_online_cpu(cpu)
+ if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
+ NOTIFY_BAD)
+ goto cleanup;
+ __register_cpu_notifier(&pool->notifier);
+ cpu_notifier_register_done();
+ return 0;
+
+cleanup:
+ for_each_online_cpu(cpu)
+ __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
+ cpu_notifier_register_done();
+ return -ENOMEM;
+}
+
+static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
+{
+ unsigned long cpu;
+
+ cpu_notifier_register_begin();
+ for_each_online_cpu(cpu)
+ __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
+ __unregister_cpu_notifier(&pool->notifier);
+ cpu_notifier_register_done();
+}
+
/*********************************
-* helpers
+* pool functions
**********************************/
-static bool zswap_is_full(void)
+
+static struct zswap_pool *__zswap_pool_current(void)
{
- return totalram_pages * zswap_max_pool_percent / 100 <
- DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
+ struct zswap_pool *pool;
+
+ pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
+ WARN_ON(!pool);
+
+ return pool;
+}
+
+static struct zswap_pool *zswap_pool_current(void)
+{
+ assert_spin_locked(&zswap_pools_lock);
+
+ return __zswap_pool_current();
+}
+
+static struct zswap_pool *zswap_pool_current_get(void)
+{
+ struct zswap_pool *pool;
+
+ rcu_read_lock();
+
+ pool = __zswap_pool_current();
+ if (!pool || !zswap_pool_get(pool))
+ pool = NULL;
+
+ rcu_read_unlock();
+
+ return pool;
+}
+
+static struct zswap_pool *zswap_pool_last_get(void)
+{
+ struct zswap_pool *pool, *last = NULL;
+
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(pool, &zswap_pools, list)
+ last = pool;
+ if (!WARN_ON(!last) && !zswap_pool_get(last))
+ last = NULL;
+
+ rcu_read_unlock();
+
+ return last;
+}
+
+static struct zpool_ops zswap_zpool_ops = {
+ .evict = zswap_writeback_entry
+};
+
+static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
+{
+ struct zswap_pool *pool;
+
+ assert_spin_locked(&zswap_pools_lock);
+
+ list_for_each_entry_rcu(pool, &zswap_pools, list) {
+ if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
+ continue;
+ if (strncmp(zpool_get_type(pool->zpool), type,
+ sizeof(zswap_zpool_type)))
+ continue;
+ /* if we can't get it, it's about to be destroyed */
+ if (!zswap_pool_get(pool))
+ continue;
+ return pool;
+ }
+
+ return NULL;
+}
+
+static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
+{
+ struct zswap_pool *pool;
+ gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
+
+ pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+ if (!pool) {
+ pr_err("pool alloc failed\n");
+ return NULL;
+ }
+
+ pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
+ if (!pool->zpool) {
+ pr_err("%s zpool not available\n", type);
+ goto error;
+ }
+ pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
+
+ strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
+ pool->tfm = alloc_percpu(struct crypto_comp *);
+ if (!pool->tfm) {
+ pr_err("percpu alloc failed\n");
+ goto error;
+ }
+
+ if (zswap_cpu_comp_init(pool))
+ goto error;
+ pr_debug("using %s compressor\n", pool->tfm_name);
+
+ /* being the current pool takes 1 ref; this func expects the
+ * caller to always add the new pool as the current pool
+ */
+ kref_init(&pool->kref);
+ INIT_LIST_HEAD(&pool->list);
+
+ zswap_pool_debug("created", pool);
+
+ return pool;
+
+error:
+ free_percpu(pool->tfm);
+ if (pool->zpool)
+ zpool_destroy_pool(pool->zpool);
+ kfree(pool);
+ return NULL;
+}
+
+static struct zswap_pool *__zswap_pool_create_fallback(void)
+{
+ if (!crypto_has_comp(zswap_compressor, 0, 0)) {
+ pr_err("compressor %s not available, using default %s\n",
+ zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
+ strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
+ sizeof(zswap_compressor));
+ }
+ if (!zpool_has_pool(zswap_zpool_type)) {
+ pr_err("zpool %s not available, using default %s\n",
+ zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
+ strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
+ sizeof(zswap_zpool_type));
+ }
+
+ return zswap_pool_create(zswap_zpool_type, zswap_compressor);
+}
+
+static void zswap_pool_destroy(struct zswap_pool *pool)
+{
+ zswap_pool_debug("destroying", pool);
+
+ zswap_cpu_comp_destroy(pool);
+ free_percpu(pool->tfm);
+ zpool_destroy_pool(pool->zpool);
+ kfree(pool);
+}
+
+static int __must_check zswap_pool_get(struct zswap_pool *pool)
+{
+ return kref_get_unless_zero(&pool->kref);
+}
+
+static void __zswap_pool_release(struct rcu_head *head)
+{
+ struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
+
+ /* nobody should have been able to get a kref... */
+ WARN_ON(kref_get_unless_zero(&pool->kref));
+
+ /* pool is now off zswap_pools list and has no references. */
+ zswap_pool_destroy(pool);
+}
+
+static void __zswap_pool_empty(struct kref *kref)
+{
+ struct zswap_pool *pool;
+
+ pool = container_of(kref, typeof(*pool), kref);
+
+ spin_lock(&zswap_pools_lock);
+
+ WARN_ON(pool == zswap_pool_current());
+
+ list_del_rcu(&pool->list);
+ call_rcu(&pool->rcu_head, __zswap_pool_release);
+
+ spin_unlock(&zswap_pools_lock);
+}
+
+static void zswap_pool_put(struct zswap_pool *pool)
+{
+ kref_put(&pool->kref, __zswap_pool_empty);
+}
+
}
/*********************************
@@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
pgoff_t offset;
struct zswap_entry *entry;
struct page *page;
+ struct crypto_comp *tfm;
u8 *src, *dst;
unsigned int dlen;
int ret;
@@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
case ZSWAP_SWAPCACHE_NEW: /* page is locked */
/* decompress */
dlen = PAGE_SIZE;
- src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
+ src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
ZPOOL_MM_RO) + sizeof(struct zswap_header);
dst = kmap_atomic(page);
- ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
- entry->length, dst, &dlen);
+ tfm = *get_cpu_ptr(entry->pool->tfm);
+ ret = crypto_comp_decompress(tfm, src, entry->length,
+ dst, &dlen);
+ put_cpu_ptr(entry->pool->tfm);
kunmap_atomic(dst);
- zpool_unmap_handle(zswap_pool, entry->handle);
+ zpool_unmap_handle(entry->pool->zpool, entry->handle);
BUG_ON(ret);
BUG_ON(dlen != PAGE_SIZE);
@@ -633,6 +882,22 @@ end:
return ret;
}
+static int zswap_shrink(void)
+{
+ struct zswap_pool *pool;
+ int ret;
+
+ pool = zswap_pool_last_get();
+ if (!pool)
+ return -ENOENT;
+
+ ret = zpool_shrink(pool->zpool, 1, NULL);
+
+ zswap_pool_put(pool);
+
+ return ret;
+}
+
/*********************************
* frontswap hooks
**********************************/
@@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
{
struct zswap_tree *tree = zswap_trees[type];
struct zswap_entry *entry, *dupentry;
+ struct crypto_comp *tfm;
int ret;
unsigned int dlen = PAGE_SIZE, len;
unsigned long handle;
@@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
/* reclaim space if needed */
if (zswap_is_full()) {
zswap_pool_limit_hit++;
- if (zpool_shrink(zswap_pool, 1, NULL)) {
+ if (zswap_shrink()) {
zswap_reject_reclaim_fail++;
ret = -ENOMEM;
goto reject;
@@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
goto reject;
}
+ /* if entry is successfully added, it keeps the reference */
+ entry->pool = zswap_pool_current_get();
+ if (!entry->pool) {
+ ret = -EINVAL;
+ goto freepage;
+ }
+
/* compress */
dst = get_cpu_var(zswap_dstmem);
+ tfm = *get_cpu_ptr(entry->pool->tfm);
src = kmap_atomic(page);
- ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
+ ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
kunmap_atomic(src);
+ put_cpu_ptr(entry->pool->tfm);
if (ret) {
ret = -EINVAL;
- goto freepage;
+ goto put_dstmem;
}
/* store */
len = dlen + sizeof(struct zswap_header);
- ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
- &handle);
+ ret = zpool_malloc(entry->pool->zpool, len,
+ __GFP_NORETRY | __GFP_NOWARN, &handle);
if (ret == -ENOSPC) {
zswap_reject_compress_poor++;
- goto freepage;
+ goto put_dstmem;
}
if (ret) {
zswap_reject_alloc_fail++;
- goto freepage;
+ goto put_dstmem;
}
- zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
+ zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
zhdr->swpentry = swp_entry(type, offset);
buf = (u8 *)(zhdr + 1);
memcpy(buf, dst, dlen);
- zpool_unmap_handle(zswap_pool, handle);
+ zpool_unmap_handle(entry->pool->zpool, handle);
put_cpu_var(zswap_dstmem);
/* populate entry */
@@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
/* update stats */
atomic_inc(&zswap_stored_pages);
- zswap_pool_total_size = zpool_get_total_size(zswap_pool);
+ zswap_update_total_size();
return 0;
-freepage:
+put_dstmem:
put_cpu_var(zswap_dstmem);
+ zswap_pool_put(entry->pool);
+freepage:
zswap_entry_cache_free(entry);
reject:
return ret;
@@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
{
struct zswap_tree *tree = zswap_trees[type];
struct zswap_entry *entry;
+ struct crypto_comp *tfm;
u8 *src, *dst;
unsigned int dlen;
int ret;
@@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
/* decompress */
dlen = PAGE_SIZE;
- src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
+ src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
ZPOOL_MM_RO) + sizeof(struct zswap_header);
dst = kmap_atomic(page);
- ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
- dst, &dlen);
+ tfm = *get_cpu_ptr(entry->pool->tfm);
+ ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
+ put_cpu_ptr(entry->pool->tfm);
kunmap_atomic(dst);
- zpool_unmap_handle(zswap_pool, entry->handle);
+ zpool_unmap_handle(entry->pool->zpool, entry->handle);
BUG_ON(ret);
spin_lock(&tree->lock);
@@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
zswap_trees[type] = NULL;
}
-static struct zpool_ops zswap_zpool_ops = {
- .evict = zswap_writeback_entry
-};
-
static void zswap_frontswap_init(unsigned type)
{
struct zswap_tree *tree;
@@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
**********************************/
static int __init init_zswap(void)
{
- gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
+ struct zswap_pool *pool;
- pr_info("loading zswap\n");
-
- zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
- &zswap_zpool_ops);
- if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
- pr_info("%s zpool not available\n", zswap_zpool_type);
- zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
- zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
- &zswap_zpool_ops);
- }
- if (!zswap_pool) {
- pr_err("%s zpool not available\n", zswap_zpool_type);
- pr_err("zpool creation failed\n");
- goto error;
- }
- pr_info("using %s pool\n", zswap_zpool_type);
+ pr_info("loading\n");
if (zswap_entry_cache_create()) {
pr_err("entry cache creation failed\n");
- goto cachefail;
+ goto cache_fail;
}
- if (zswap_comp_init()) {
- pr_err("compressor initialization failed\n");
- goto compfail;
+
+ if (zswap_cpu_dstmem_init()) {
+ pr_err("dstmem alloc failed\n");
+ goto dstmem_fail;
}
- if (zswap_cpu_init()) {
- pr_err("per-cpu initialization failed\n");
- goto pcpufail;
+
+ pool = __zswap_pool_create_fallback();
+ if (!pool) {
+ pr_err("pool creation failed\n");
+ goto pool_fail;
}
+ pr_info("loaded using pool %s/%s\n", pool->tfm_name,
+ zpool_get_type(pool->zpool));
+
+ list_add(&pool->list, &zswap_pools);
frontswap_register_ops(&zswap_frontswap_ops);
if (zswap_debugfs_init())
pr_warn("debugfs initialization failed\n");
return 0;
-pcpufail:
- zswap_comp_exit();
-compfail:
+
+pool_fail:
+ zswap_cpu_dstmem_destroy();
+dstmem_fail:
zswap_entry_cache_destroy();
-cachefail:
- zpool_destroy_pool(zswap_pool);
-error:
+cache_fail:
return -ENOMEM;
}
/* must be late so crypto has time to come up */
--
2.1.0
^ permalink raw reply related [flat|nested] 22+ messages in thread
* [PATCH] zswap: dynamic pool creation
@ 2015-06-04 12:02 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-04 12:02 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: linux-mm, linux-kernel, Dan Streetman
Add dynamic creation of pools. Move the static crypto compression
per-cpu transforms into each pool. Add a pointer to zswap_entry to
the pool it's in.
This is required by a separate patch which enables changing the
zswap zpool and compressor params at runtime.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
---
mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 408 insertions(+), 142 deletions(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index 2d5727b..fc93770 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
static struct zpool *zswap_pool;
/*********************************
-* compression functions
+* data structures
**********************************/
-/* per-cpu compression transforms */
-static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
-enum comp_op {
- ZSWAP_COMPOP_COMPRESS,
- ZSWAP_COMPOP_DECOMPRESS
+struct zswap_pool {
+ struct zpool *zpool;
+ struct kref kref;
+ struct list_head list;
+ struct rcu_head rcu_head;
+ struct notifier_block notifier;
+ char tfm_name[CRYPTO_MAX_ALG_NAME];
+ struct crypto_comp * __percpu *tfm;
};
-static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
- u8 *dst, unsigned int *dlen)
-{
- struct crypto_comp *tfm;
- int ret;
-
- tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
- switch (op) {
- case ZSWAP_COMPOP_COMPRESS:
- ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
- break;
- case ZSWAP_COMPOP_DECOMPRESS:
- ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
- break;
- default:
- ret = -EINVAL;
- }
-
- put_cpu();
- return ret;
-}
-
-static int __init zswap_comp_init(void)
-{
- if (!crypto_has_comp(zswap_compressor, 0, 0)) {
- pr_info("%s compressor not available\n", zswap_compressor);
- /* fall back to default compressor */
- zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
- if (!crypto_has_comp(zswap_compressor, 0, 0))
- /* can't even load the default compressor */
- return -ENODEV;
- }
- pr_info("using %s compressor\n", zswap_compressor);
-
- /* alloc percpu transforms */
- zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
- if (!zswap_comp_pcpu_tfms)
- return -ENOMEM;
- return 0;
-}
-
-static void __init zswap_comp_exit(void)
-{
- /* free percpu transforms */
- free_percpu(zswap_comp_pcpu_tfms);
-}
-
-/*********************************
-* data structures
-**********************************/
/*
* struct zswap_entry
*
@@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
* page within zswap.
*
* rbnode - links the entry into red-black tree for the appropriate swap type
+ * offset - the swap offset for the entry. Index into the red-black tree.
* refcount - the number of outstanding reference to the entry. This is needed
* to protect against premature freeing of the entry by code
* concurrent calls to load, invalidate, and writeback. The lock
* for the zswap_tree structure that contains the entry must
* be held while changing the refcount. Since the lock must
* be held, there is no reason to also make refcount atomic.
- * offset - the swap offset for the entry. Index into the red-black tree.
- * handle - zpool allocation handle that stores the compressed page data
* length - the length in bytes of the compressed page data. Needed during
* decompression
+ * pool - the zswap_pool the entry's data is in
+ * handle - zpool allocation handle that stores the compressed page data
*/
struct zswap_entry {
struct rb_node rbnode;
pgoff_t offset;
int refcount;
unsigned int length;
+ struct zswap_pool *pool;
unsigned long handle;
};
@@ -201,6 +156,44 @@ struct zswap_tree {
static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
+/* RCU-protected iteration */
+static LIST_HEAD(zswap_pools);
+/* protects zswap_pools list modification */
+static DEFINE_SPINLOCK(zswap_pools_lock);
+
+/*********************************
+* helpers and fwd declarations
+**********************************/
+
+#define zswap_pool_debug(msg, p) \
+ pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
+ zpool_get_type((p)->zpool))
+
+static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
+static int zswap_pool_get(struct zswap_pool *pool);
+static void zswap_pool_put(struct zswap_pool *pool);
+
+static bool zswap_is_full(void)
+{
+ return totalram_pages * zswap_max_pool_percent / 100 <
+ DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
+}
+
+static void zswap_update_total_size(void)
+{
+ struct zswap_pool *pool;
+ u64 total = 0;
+
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(pool, &zswap_pools, list)
+ total += zpool_get_total_size(pool->zpool);
+
+ rcu_read_unlock();
+
+ zswap_pool_total_size = total;
+}
+
/*********************************
* zswap entry functions
**********************************/
@@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
*/
static void zswap_free_entry(struct zswap_entry *entry)
{
- zpool_free(zswap_pool, entry->handle);
+ zpool_free(entry->pool->zpool, entry->handle);
+ zswap_pool_put(entry->pool);
zswap_entry_cache_free(entry);
atomic_dec(&zswap_stored_pages);
- zswap_pool_total_size = zpool_get_total_size(zswap_pool);
+ zswap_update_total_size();
}
/* caller must hold the tree lock */
@@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
**********************************/
static DEFINE_PER_CPU(u8 *, zswap_dstmem);
-static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
+static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
{
- struct crypto_comp *tfm;
u8 *dst;
switch (action) {
case CPU_UP_PREPARE:
- tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
- if (IS_ERR(tfm)) {
- pr_err("can't allocate compressor transform\n");
- return NOTIFY_BAD;
- }
- *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
if (!dst) {
pr_err("can't allocate compressor buffer\n");
- crypto_free_comp(tfm);
- *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
return NOTIFY_BAD;
}
per_cpu(zswap_dstmem, cpu) = dst;
break;
case CPU_DEAD:
case CPU_UP_CANCELED:
- tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
- if (tfm) {
- crypto_free_comp(tfm);
- *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
- }
dst = per_cpu(zswap_dstmem, cpu);
kfree(dst);
per_cpu(zswap_dstmem, cpu) = NULL;
@@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
return NOTIFY_OK;
}
-static int zswap_cpu_notifier(struct notifier_block *nb,
- unsigned long action, void *pcpu)
+static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
+ unsigned long action, void *pcpu)
{
- unsigned long cpu = (unsigned long)pcpu;
- return __zswap_cpu_notifier(action, cpu);
+ return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
}
-static struct notifier_block zswap_cpu_notifier_block = {
- .notifier_call = zswap_cpu_notifier
+static struct notifier_block zswap_dstmem_notifier = {
+ .notifier_call = zswap_cpu_dstmem_notifier,
};
-static int __init zswap_cpu_init(void)
+static int __init zswap_cpu_dstmem_init(void)
{
unsigned long cpu;
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
- if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
+ if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
+ NOTIFY_BAD)
goto cleanup;
- __register_cpu_notifier(&zswap_cpu_notifier_block);
+ __register_cpu_notifier(&zswap_dstmem_notifier);
cpu_notifier_register_done();
return 0;
cleanup:
for_each_online_cpu(cpu)
- __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
+ __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
cpu_notifier_register_done();
return -ENOMEM;
}
+static void zswap_cpu_dstmem_destroy(void)
+{
+ unsigned long cpu;
+
+ cpu_notifier_register_begin();
+ for_each_online_cpu(cpu)
+ __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
+ __unregister_cpu_notifier(&zswap_dstmem_notifier);
+ cpu_notifier_register_done();
+}
+
+static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
+ unsigned long action, unsigned long cpu)
+{
+ struct crypto_comp *tfm;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
+ break;
+ tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
+ if (IS_ERR_OR_NULL(tfm)) {
+ pr_err("could not alloc crypto comp %s : %ld\n",
+ pool->tfm_name, PTR_ERR(tfm));
+ return NOTIFY_BAD;
+ }
+ *per_cpu_ptr(pool->tfm, cpu) = tfm;
+ break;
+ case CPU_DEAD:
+ case CPU_UP_CANCELED:
+ tfm = *per_cpu_ptr(pool->tfm, cpu);
+ if (!IS_ERR_OR_NULL(tfm))
+ crypto_free_comp(tfm);
+ *per_cpu_ptr(pool->tfm, cpu) = NULL;
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static int zswap_cpu_comp_notifier(struct notifier_block *nb,
+ unsigned long action, void *pcpu)
+{
+ unsigned long cpu = (unsigned long)pcpu;
+ struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
+
+ return __zswap_cpu_comp_notifier(pool, action, cpu);
+}
+
+static int zswap_cpu_comp_init(struct zswap_pool *pool)
+{
+ unsigned long cpu;
+
+ memset(&pool->notifier, 0, sizeof(pool->notifier));
+ pool->notifier.notifier_call = zswap_cpu_comp_notifier;
+
+ cpu_notifier_register_begin();
+ for_each_online_cpu(cpu)
+ if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
+ NOTIFY_BAD)
+ goto cleanup;
+ __register_cpu_notifier(&pool->notifier);
+ cpu_notifier_register_done();
+ return 0;
+
+cleanup:
+ for_each_online_cpu(cpu)
+ __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
+ cpu_notifier_register_done();
+ return -ENOMEM;
+}
+
+static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
+{
+ unsigned long cpu;
+
+ cpu_notifier_register_begin();
+ for_each_online_cpu(cpu)
+ __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
+ __unregister_cpu_notifier(&pool->notifier);
+ cpu_notifier_register_done();
+}
+
/*********************************
-* helpers
+* pool functions
**********************************/
-static bool zswap_is_full(void)
+
+static struct zswap_pool *__zswap_pool_current(void)
{
- return totalram_pages * zswap_max_pool_percent / 100 <
- DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
+ struct zswap_pool *pool;
+
+ pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
+ WARN_ON(!pool);
+
+ return pool;
+}
+
+static struct zswap_pool *zswap_pool_current(void)
+{
+ assert_spin_locked(&zswap_pools_lock);
+
+ return __zswap_pool_current();
+}
+
+static struct zswap_pool *zswap_pool_current_get(void)
+{
+ struct zswap_pool *pool;
+
+ rcu_read_lock();
+
+ pool = __zswap_pool_current();
+ if (!pool || !zswap_pool_get(pool))
+ pool = NULL;
+
+ rcu_read_unlock();
+
+ return pool;
+}
+
+static struct zswap_pool *zswap_pool_last_get(void)
+{
+ struct zswap_pool *pool, *last = NULL;
+
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(pool, &zswap_pools, list)
+ last = pool;
+ if (!WARN_ON(!last) && !zswap_pool_get(last))
+ last = NULL;
+
+ rcu_read_unlock();
+
+ return last;
+}
+
+static struct zpool_ops zswap_zpool_ops = {
+ .evict = zswap_writeback_entry
+};
+
+static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
+{
+ struct zswap_pool *pool;
+
+ assert_spin_locked(&zswap_pools_lock);
+
+ list_for_each_entry_rcu(pool, &zswap_pools, list) {
+ if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
+ continue;
+ if (strncmp(zpool_get_type(pool->zpool), type,
+ sizeof(zswap_zpool_type)))
+ continue;
+ /* if we can't get it, it's about to be destroyed */
+ if (!zswap_pool_get(pool))
+ continue;
+ return pool;
+ }
+
+ return NULL;
+}
+
+static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
+{
+ struct zswap_pool *pool;
+ gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
+
+ pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+ if (!pool) {
+ pr_err("pool alloc failed\n");
+ return NULL;
+ }
+
+ pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
+ if (!pool->zpool) {
+ pr_err("%s zpool not available\n", type);
+ goto error;
+ }
+ pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
+
+ strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
+ pool->tfm = alloc_percpu(struct crypto_comp *);
+ if (!pool->tfm) {
+ pr_err("percpu alloc failed\n");
+ goto error;
+ }
+
+ if (zswap_cpu_comp_init(pool))
+ goto error;
+ pr_debug("using %s compressor\n", pool->tfm_name);
+
+ /* being the current pool takes 1 ref; this func expects the
+ * caller to always add the new pool as the current pool
+ */
+ kref_init(&pool->kref);
+ INIT_LIST_HEAD(&pool->list);
+
+ zswap_pool_debug("created", pool);
+
+ return pool;
+
+error:
+ free_percpu(pool->tfm);
+ if (pool->zpool)
+ zpool_destroy_pool(pool->zpool);
+ kfree(pool);
+ return NULL;
+}
+
+static struct zswap_pool *__zswap_pool_create_fallback(void)
+{
+ if (!crypto_has_comp(zswap_compressor, 0, 0)) {
+ pr_err("compressor %s not available, using default %s\n",
+ zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
+ strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
+ sizeof(zswap_compressor));
+ }
+ if (!zpool_has_pool(zswap_zpool_type)) {
+ pr_err("zpool %s not available, using default %s\n",
+ zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
+ strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
+ sizeof(zswap_zpool_type));
+ }
+
+ return zswap_pool_create(zswap_zpool_type, zswap_compressor);
+}
+
+static void zswap_pool_destroy(struct zswap_pool *pool)
+{
+ zswap_pool_debug("destroying", pool);
+
+ zswap_cpu_comp_destroy(pool);
+ free_percpu(pool->tfm);
+ zpool_destroy_pool(pool->zpool);
+ kfree(pool);
+}
+
+static int __must_check zswap_pool_get(struct zswap_pool *pool)
+{
+ return kref_get_unless_zero(&pool->kref);
+}
+
+static void __zswap_pool_release(struct rcu_head *head)
+{
+ struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
+
+ /* nobody should have been able to get a kref... */
+ WARN_ON(kref_get_unless_zero(&pool->kref));
+
+ /* pool is now off zswap_pools list and has no references. */
+ zswap_pool_destroy(pool);
+}
+
+static void __zswap_pool_empty(struct kref *kref)
+{
+ struct zswap_pool *pool;
+
+ pool = container_of(kref, typeof(*pool), kref);
+
+ spin_lock(&zswap_pools_lock);
+
+ WARN_ON(pool == zswap_pool_current());
+
+ list_del_rcu(&pool->list);
+ call_rcu(&pool->rcu_head, __zswap_pool_release);
+
+ spin_unlock(&zswap_pools_lock);
+}
+
+static void zswap_pool_put(struct zswap_pool *pool)
+{
+ kref_put(&pool->kref, __zswap_pool_empty);
+}
+
}
/*********************************
@@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
pgoff_t offset;
struct zswap_entry *entry;
struct page *page;
+ struct crypto_comp *tfm;
u8 *src, *dst;
unsigned int dlen;
int ret;
@@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
case ZSWAP_SWAPCACHE_NEW: /* page is locked */
/* decompress */
dlen = PAGE_SIZE;
- src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
+ src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
ZPOOL_MM_RO) + sizeof(struct zswap_header);
dst = kmap_atomic(page);
- ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
- entry->length, dst, &dlen);
+ tfm = *get_cpu_ptr(entry->pool->tfm);
+ ret = crypto_comp_decompress(tfm, src, entry->length,
+ dst, &dlen);
+ put_cpu_ptr(entry->pool->tfm);
kunmap_atomic(dst);
- zpool_unmap_handle(zswap_pool, entry->handle);
+ zpool_unmap_handle(entry->pool->zpool, entry->handle);
BUG_ON(ret);
BUG_ON(dlen != PAGE_SIZE);
@@ -633,6 +882,22 @@ end:
return ret;
}
+static int zswap_shrink(void)
+{
+ struct zswap_pool *pool;
+ int ret;
+
+ pool = zswap_pool_last_get();
+ if (!pool)
+ return -ENOENT;
+
+ ret = zpool_shrink(pool->zpool, 1, NULL);
+
+ zswap_pool_put(pool);
+
+ return ret;
+}
+
/*********************************
* frontswap hooks
**********************************/
@@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
{
struct zswap_tree *tree = zswap_trees[type];
struct zswap_entry *entry, *dupentry;
+ struct crypto_comp *tfm;
int ret;
unsigned int dlen = PAGE_SIZE, len;
unsigned long handle;
@@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
/* reclaim space if needed */
if (zswap_is_full()) {
zswap_pool_limit_hit++;
- if (zpool_shrink(zswap_pool, 1, NULL)) {
+ if (zswap_shrink()) {
zswap_reject_reclaim_fail++;
ret = -ENOMEM;
goto reject;
@@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
goto reject;
}
+ /* if entry is successfully added, it keeps the reference */
+ entry->pool = zswap_pool_current_get();
+ if (!entry->pool) {
+ ret = -EINVAL;
+ goto freepage;
+ }
+
/* compress */
dst = get_cpu_var(zswap_dstmem);
+ tfm = *get_cpu_ptr(entry->pool->tfm);
src = kmap_atomic(page);
- ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
+ ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
kunmap_atomic(src);
+ put_cpu_ptr(entry->pool->tfm);
if (ret) {
ret = -EINVAL;
- goto freepage;
+ goto put_dstmem;
}
/* store */
len = dlen + sizeof(struct zswap_header);
- ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
- &handle);
+ ret = zpool_malloc(entry->pool->zpool, len,
+ __GFP_NORETRY | __GFP_NOWARN, &handle);
if (ret == -ENOSPC) {
zswap_reject_compress_poor++;
- goto freepage;
+ goto put_dstmem;
}
if (ret) {
zswap_reject_alloc_fail++;
- goto freepage;
+ goto put_dstmem;
}
- zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
+ zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
zhdr->swpentry = swp_entry(type, offset);
buf = (u8 *)(zhdr + 1);
memcpy(buf, dst, dlen);
- zpool_unmap_handle(zswap_pool, handle);
+ zpool_unmap_handle(entry->pool->zpool, handle);
put_cpu_var(zswap_dstmem);
/* populate entry */
@@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
/* update stats */
atomic_inc(&zswap_stored_pages);
- zswap_pool_total_size = zpool_get_total_size(zswap_pool);
+ zswap_update_total_size();
return 0;
-freepage:
+put_dstmem:
put_cpu_var(zswap_dstmem);
+ zswap_pool_put(entry->pool);
+freepage:
zswap_entry_cache_free(entry);
reject:
return ret;
@@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
{
struct zswap_tree *tree = zswap_trees[type];
struct zswap_entry *entry;
+ struct crypto_comp *tfm;
u8 *src, *dst;
unsigned int dlen;
int ret;
@@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
/* decompress */
dlen = PAGE_SIZE;
- src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
+ src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
ZPOOL_MM_RO) + sizeof(struct zswap_header);
dst = kmap_atomic(page);
- ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
- dst, &dlen);
+ tfm = *get_cpu_ptr(entry->pool->tfm);
+ ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
+ put_cpu_ptr(entry->pool->tfm);
kunmap_atomic(dst);
- zpool_unmap_handle(zswap_pool, entry->handle);
+ zpool_unmap_handle(entry->pool->zpool, entry->handle);
BUG_ON(ret);
spin_lock(&tree->lock);
@@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
zswap_trees[type] = NULL;
}
-static struct zpool_ops zswap_zpool_ops = {
- .evict = zswap_writeback_entry
-};
-
static void zswap_frontswap_init(unsigned type)
{
struct zswap_tree *tree;
@@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
**********************************/
static int __init init_zswap(void)
{
- gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
+ struct zswap_pool *pool;
- pr_info("loading zswap\n");
-
- zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
- &zswap_zpool_ops);
- if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
- pr_info("%s zpool not available\n", zswap_zpool_type);
- zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
- zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
- &zswap_zpool_ops);
- }
- if (!zswap_pool) {
- pr_err("%s zpool not available\n", zswap_zpool_type);
- pr_err("zpool creation failed\n");
- goto error;
- }
- pr_info("using %s pool\n", zswap_zpool_type);
+ pr_info("loading\n");
if (zswap_entry_cache_create()) {
pr_err("entry cache creation failed\n");
- goto cachefail;
+ goto cache_fail;
}
- if (zswap_comp_init()) {
- pr_err("compressor initialization failed\n");
- goto compfail;
+
+ if (zswap_cpu_dstmem_init()) {
+ pr_err("dstmem alloc failed\n");
+ goto dstmem_fail;
}
- if (zswap_cpu_init()) {
- pr_err("per-cpu initialization failed\n");
- goto pcpufail;
+
+ pool = __zswap_pool_create_fallback();
+ if (!pool) {
+ pr_err("pool creation failed\n");
+ goto pool_fail;
}
+ pr_info("loaded using pool %s/%s\n", pool->tfm_name,
+ zpool_get_type(pool->zpool));
+
+ list_add(&pool->list, &zswap_pools);
frontswap_register_ops(&zswap_frontswap_ops);
if (zswap_debugfs_init())
pr_warn("debugfs initialization failed\n");
return 0;
-pcpufail:
- zswap_comp_exit();
-compfail:
+
+pool_fail:
+ zswap_cpu_dstmem_destroy();
+dstmem_fail:
zswap_entry_cache_destroy();
-cachefail:
- zpool_destroy_pool(zswap_pool);
-error:
+cache_fail:
return -ENOMEM;
}
/* must be late so crypto has time to come up */
--
2.1.0
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^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-04 12:02 ` Dan Streetman
@ 2015-06-04 12:13 ` Dan Streetman
-1 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-04 12:13 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> Add dynamic creation of pools. Move the static crypto compression
> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> the pool it's in.
Seth, as far as the design, from your previous comments I assume you
were thinking of maintaining separate lists of zpools and compressors?
I do see how that will reduce duplication of zpools and compressors,
but it also requires adding a new pointer to each zswap_entry, and
increasing the amount of code to manage each list separately. And the
most common case in zswap will be just a single zpool and compressor,
not repeatedly changing params. What do you think?
>
> This is required by a separate patch which enables changing the
> zswap zpool and compressor params at runtime.
>
> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> ---
> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 408 insertions(+), 142 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 2d5727b..fc93770 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> static struct zpool *zswap_pool;
>
> /*********************************
> -* compression functions
> +* data structures
> **********************************/
> -/* per-cpu compression transforms */
> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>
> -enum comp_op {
> - ZSWAP_COMPOP_COMPRESS,
> - ZSWAP_COMPOP_DECOMPRESS
> +struct zswap_pool {
> + struct zpool *zpool;
> + struct kref kref;
> + struct list_head list;
> + struct rcu_head rcu_head;
> + struct notifier_block notifier;
> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> + struct crypto_comp * __percpu *tfm;
> };
>
> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> - u8 *dst, unsigned int *dlen)
> -{
> - struct crypto_comp *tfm;
> - int ret;
> -
> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> - switch (op) {
> - case ZSWAP_COMPOP_COMPRESS:
> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> - break;
> - case ZSWAP_COMPOP_DECOMPRESS:
> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> - break;
> - default:
> - ret = -EINVAL;
> - }
> -
> - put_cpu();
> - return ret;
> -}
> -
> -static int __init zswap_comp_init(void)
> -{
> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> - pr_info("%s compressor not available\n", zswap_compressor);
> - /* fall back to default compressor */
> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> - /* can't even load the default compressor */
> - return -ENODEV;
> - }
> - pr_info("using %s compressor\n", zswap_compressor);
> -
> - /* alloc percpu transforms */
> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> - if (!zswap_comp_pcpu_tfms)
> - return -ENOMEM;
> - return 0;
> -}
> -
> -static void __init zswap_comp_exit(void)
> -{
> - /* free percpu transforms */
> - free_percpu(zswap_comp_pcpu_tfms);
> -}
> -
> -/*********************************
> -* data structures
> -**********************************/
> /*
> * struct zswap_entry
> *
> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> * page within zswap.
> *
> * rbnode - links the entry into red-black tree for the appropriate swap type
> + * offset - the swap offset for the entry. Index into the red-black tree.
> * refcount - the number of outstanding reference to the entry. This is needed
> * to protect against premature freeing of the entry by code
> * concurrent calls to load, invalidate, and writeback. The lock
> * for the zswap_tree structure that contains the entry must
> * be held while changing the refcount. Since the lock must
> * be held, there is no reason to also make refcount atomic.
> - * offset - the swap offset for the entry. Index into the red-black tree.
> - * handle - zpool allocation handle that stores the compressed page data
> * length - the length in bytes of the compressed page data. Needed during
> * decompression
> + * pool - the zswap_pool the entry's data is in
> + * handle - zpool allocation handle that stores the compressed page data
> */
> struct zswap_entry {
> struct rb_node rbnode;
> pgoff_t offset;
> int refcount;
> unsigned int length;
> + struct zswap_pool *pool;
> unsigned long handle;
> };
>
> @@ -201,6 +156,44 @@ struct zswap_tree {
>
> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>
> +/* RCU-protected iteration */
> +static LIST_HEAD(zswap_pools);
> +/* protects zswap_pools list modification */
> +static DEFINE_SPINLOCK(zswap_pools_lock);
> +
> +/*********************************
> +* helpers and fwd declarations
> +**********************************/
> +
> +#define zswap_pool_debug(msg, p) \
> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> + zpool_get_type((p)->zpool))
> +
> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> +static int zswap_pool_get(struct zswap_pool *pool);
> +static void zswap_pool_put(struct zswap_pool *pool);
> +
> +static bool zswap_is_full(void)
> +{
> + return totalram_pages * zswap_max_pool_percent / 100 <
> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> +}
> +
> +static void zswap_update_total_size(void)
> +{
> + struct zswap_pool *pool;
> + u64 total = 0;
> +
> + rcu_read_lock();
> +
> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> + total += zpool_get_total_size(pool->zpool);
> +
> + rcu_read_unlock();
> +
> + zswap_pool_total_size = total;
> +}
> +
> /*********************************
> * zswap entry functions
> **********************************/
> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> */
> static void zswap_free_entry(struct zswap_entry *entry)
> {
> - zpool_free(zswap_pool, entry->handle);
> + zpool_free(entry->pool->zpool, entry->handle);
> + zswap_pool_put(entry->pool);
> zswap_entry_cache_free(entry);
> atomic_dec(&zswap_stored_pages);
> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> + zswap_update_total_size();
> }
>
> /* caller must hold the tree lock */
> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> **********************************/
> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>
> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> {
> - struct crypto_comp *tfm;
> u8 *dst;
>
> switch (action) {
> case CPU_UP_PREPARE:
> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> - if (IS_ERR(tfm)) {
> - pr_err("can't allocate compressor transform\n");
> - return NOTIFY_BAD;
> - }
> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> if (!dst) {
> pr_err("can't allocate compressor buffer\n");
> - crypto_free_comp(tfm);
> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> return NOTIFY_BAD;
> }
> per_cpu(zswap_dstmem, cpu) = dst;
> break;
> case CPU_DEAD:
> case CPU_UP_CANCELED:
> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> - if (tfm) {
> - crypto_free_comp(tfm);
> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> - }
> dst = per_cpu(zswap_dstmem, cpu);
> kfree(dst);
> per_cpu(zswap_dstmem, cpu) = NULL;
> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> return NOTIFY_OK;
> }
>
> -static int zswap_cpu_notifier(struct notifier_block *nb,
> - unsigned long action, void *pcpu)
> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> + unsigned long action, void *pcpu)
> {
> - unsigned long cpu = (unsigned long)pcpu;
> - return __zswap_cpu_notifier(action, cpu);
> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> }
>
> -static struct notifier_block zswap_cpu_notifier_block = {
> - .notifier_call = zswap_cpu_notifier
> +static struct notifier_block zswap_dstmem_notifier = {
> + .notifier_call = zswap_cpu_dstmem_notifier,
> };
>
> -static int __init zswap_cpu_init(void)
> +static int __init zswap_cpu_dstmem_init(void)
> {
> unsigned long cpu;
>
> cpu_notifier_register_begin();
> for_each_online_cpu(cpu)
> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> + NOTIFY_BAD)
> goto cleanup;
> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> + __register_cpu_notifier(&zswap_dstmem_notifier);
> cpu_notifier_register_done();
> return 0;
>
> cleanup:
> for_each_online_cpu(cpu)
> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> cpu_notifier_register_done();
> return -ENOMEM;
> }
>
> +static void zswap_cpu_dstmem_destroy(void)
> +{
> + unsigned long cpu;
> +
> + cpu_notifier_register_begin();
> + for_each_online_cpu(cpu)
> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> + cpu_notifier_register_done();
> +}
> +
> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> + unsigned long action, unsigned long cpu)
> +{
> + struct crypto_comp *tfm;
> +
> + switch (action) {
> + case CPU_UP_PREPARE:
> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> + break;
> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> + if (IS_ERR_OR_NULL(tfm)) {
> + pr_err("could not alloc crypto comp %s : %ld\n",
> + pool->tfm_name, PTR_ERR(tfm));
> + return NOTIFY_BAD;
> + }
> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> + break;
> + case CPU_DEAD:
> + case CPU_UP_CANCELED:
> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> + if (!IS_ERR_OR_NULL(tfm))
> + crypto_free_comp(tfm);
> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> + break;
> + default:
> + break;
> + }
> + return NOTIFY_OK;
> +}
> +
> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> + unsigned long action, void *pcpu)
> +{
> + unsigned long cpu = (unsigned long)pcpu;
> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> +
> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> +}
> +
> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> +{
> + unsigned long cpu;
> +
> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> +
> + cpu_notifier_register_begin();
> + for_each_online_cpu(cpu)
> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> + NOTIFY_BAD)
> + goto cleanup;
> + __register_cpu_notifier(&pool->notifier);
> + cpu_notifier_register_done();
> + return 0;
> +
> +cleanup:
> + for_each_online_cpu(cpu)
> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> + cpu_notifier_register_done();
> + return -ENOMEM;
> +}
> +
> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> +{
> + unsigned long cpu;
> +
> + cpu_notifier_register_begin();
> + for_each_online_cpu(cpu)
> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> + __unregister_cpu_notifier(&pool->notifier);
> + cpu_notifier_register_done();
> +}
> +
> /*********************************
> -* helpers
> +* pool functions
> **********************************/
> -static bool zswap_is_full(void)
> +
> +static struct zswap_pool *__zswap_pool_current(void)
> {
> - return totalram_pages * zswap_max_pool_percent / 100 <
> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> + struct zswap_pool *pool;
> +
> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> + WARN_ON(!pool);
> +
> + return pool;
> +}
> +
> +static struct zswap_pool *zswap_pool_current(void)
> +{
> + assert_spin_locked(&zswap_pools_lock);
> +
> + return __zswap_pool_current();
> +}
> +
> +static struct zswap_pool *zswap_pool_current_get(void)
> +{
> + struct zswap_pool *pool;
> +
> + rcu_read_lock();
> +
> + pool = __zswap_pool_current();
> + if (!pool || !zswap_pool_get(pool))
> + pool = NULL;
> +
> + rcu_read_unlock();
> +
> + return pool;
> +}
> +
> +static struct zswap_pool *zswap_pool_last_get(void)
> +{
> + struct zswap_pool *pool, *last = NULL;
> +
> + rcu_read_lock();
> +
> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> + last = pool;
> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> + last = NULL;
> +
> + rcu_read_unlock();
> +
> + return last;
> +}
> +
> +static struct zpool_ops zswap_zpool_ops = {
> + .evict = zswap_writeback_entry
> +};
> +
> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> +{
> + struct zswap_pool *pool;
> +
> + assert_spin_locked(&zswap_pools_lock);
> +
> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> + continue;
> + if (strncmp(zpool_get_type(pool->zpool), type,
> + sizeof(zswap_zpool_type)))
> + continue;
> + /* if we can't get it, it's about to be destroyed */
> + if (!zswap_pool_get(pool))
> + continue;
> + return pool;
> + }
> +
> + return NULL;
> +}
> +
> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> +{
> + struct zswap_pool *pool;
> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> +
> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> + if (!pool) {
> + pr_err("pool alloc failed\n");
> + return NULL;
> + }
> +
> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> + if (!pool->zpool) {
> + pr_err("%s zpool not available\n", type);
> + goto error;
> + }
> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> +
> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> + pool->tfm = alloc_percpu(struct crypto_comp *);
> + if (!pool->tfm) {
> + pr_err("percpu alloc failed\n");
> + goto error;
> + }
> +
> + if (zswap_cpu_comp_init(pool))
> + goto error;
> + pr_debug("using %s compressor\n", pool->tfm_name);
> +
> + /* being the current pool takes 1 ref; this func expects the
> + * caller to always add the new pool as the current pool
> + */
> + kref_init(&pool->kref);
> + INIT_LIST_HEAD(&pool->list);
> +
> + zswap_pool_debug("created", pool);
> +
> + return pool;
> +
> +error:
> + free_percpu(pool->tfm);
> + if (pool->zpool)
> + zpool_destroy_pool(pool->zpool);
> + kfree(pool);
> + return NULL;
> +}
> +
> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> +{
> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> + pr_err("compressor %s not available, using default %s\n",
> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> + sizeof(zswap_compressor));
> + }
> + if (!zpool_has_pool(zswap_zpool_type)) {
> + pr_err("zpool %s not available, using default %s\n",
> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> + sizeof(zswap_zpool_type));
> + }
> +
> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> +}
> +
> +static void zswap_pool_destroy(struct zswap_pool *pool)
> +{
> + zswap_pool_debug("destroying", pool);
> +
> + zswap_cpu_comp_destroy(pool);
> + free_percpu(pool->tfm);
> + zpool_destroy_pool(pool->zpool);
> + kfree(pool);
> +}
> +
> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> +{
> + return kref_get_unless_zero(&pool->kref);
> +}
> +
> +static void __zswap_pool_release(struct rcu_head *head)
> +{
> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> +
> + /* nobody should have been able to get a kref... */
> + WARN_ON(kref_get_unless_zero(&pool->kref));
> +
> + /* pool is now off zswap_pools list and has no references. */
> + zswap_pool_destroy(pool);
> +}
> +
> +static void __zswap_pool_empty(struct kref *kref)
> +{
> + struct zswap_pool *pool;
> +
> + pool = container_of(kref, typeof(*pool), kref);
> +
> + spin_lock(&zswap_pools_lock);
> +
> + WARN_ON(pool == zswap_pool_current());
> +
> + list_del_rcu(&pool->list);
> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> +
> + spin_unlock(&zswap_pools_lock);
> +}
> +
> +static void zswap_pool_put(struct zswap_pool *pool)
> +{
> + kref_put(&pool->kref, __zswap_pool_empty);
> +}
> +
> }
>
> /*********************************
> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> pgoff_t offset;
> struct zswap_entry *entry;
> struct page *page;
> + struct crypto_comp *tfm;
> u8 *src, *dst;
> unsigned int dlen;
> int ret;
> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> /* decompress */
> dlen = PAGE_SIZE;
> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> dst = kmap_atomic(page);
> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> - entry->length, dst, &dlen);
> + tfm = *get_cpu_ptr(entry->pool->tfm);
> + ret = crypto_comp_decompress(tfm, src, entry->length,
> + dst, &dlen);
> + put_cpu_ptr(entry->pool->tfm);
> kunmap_atomic(dst);
> - zpool_unmap_handle(zswap_pool, entry->handle);
> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> BUG_ON(ret);
> BUG_ON(dlen != PAGE_SIZE);
>
> @@ -633,6 +882,22 @@ end:
> return ret;
> }
>
> +static int zswap_shrink(void)
> +{
> + struct zswap_pool *pool;
> + int ret;
> +
> + pool = zswap_pool_last_get();
> + if (!pool)
> + return -ENOENT;
> +
> + ret = zpool_shrink(pool->zpool, 1, NULL);
> +
> + zswap_pool_put(pool);
> +
> + return ret;
> +}
> +
> /*********************************
> * frontswap hooks
> **********************************/
> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> {
> struct zswap_tree *tree = zswap_trees[type];
> struct zswap_entry *entry, *dupentry;
> + struct crypto_comp *tfm;
> int ret;
> unsigned int dlen = PAGE_SIZE, len;
> unsigned long handle;
> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> /* reclaim space if needed */
> if (zswap_is_full()) {
> zswap_pool_limit_hit++;
> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> + if (zswap_shrink()) {
> zswap_reject_reclaim_fail++;
> ret = -ENOMEM;
> goto reject;
> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> goto reject;
> }
>
> + /* if entry is successfully added, it keeps the reference */
> + entry->pool = zswap_pool_current_get();
> + if (!entry->pool) {
> + ret = -EINVAL;
> + goto freepage;
> + }
> +
> /* compress */
> dst = get_cpu_var(zswap_dstmem);
> + tfm = *get_cpu_ptr(entry->pool->tfm);
> src = kmap_atomic(page);
> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> kunmap_atomic(src);
> + put_cpu_ptr(entry->pool->tfm);
> if (ret) {
> ret = -EINVAL;
> - goto freepage;
> + goto put_dstmem;
> }
>
> /* store */
> len = dlen + sizeof(struct zswap_header);
> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> - &handle);
> + ret = zpool_malloc(entry->pool->zpool, len,
> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> if (ret == -ENOSPC) {
> zswap_reject_compress_poor++;
> - goto freepage;
> + goto put_dstmem;
> }
> if (ret) {
> zswap_reject_alloc_fail++;
> - goto freepage;
> + goto put_dstmem;
> }
> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> zhdr->swpentry = swp_entry(type, offset);
> buf = (u8 *)(zhdr + 1);
> memcpy(buf, dst, dlen);
> - zpool_unmap_handle(zswap_pool, handle);
> + zpool_unmap_handle(entry->pool->zpool, handle);
> put_cpu_var(zswap_dstmem);
>
> /* populate entry */
> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>
> /* update stats */
> atomic_inc(&zswap_stored_pages);
> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> + zswap_update_total_size();
>
> return 0;
>
> -freepage:
> +put_dstmem:
> put_cpu_var(zswap_dstmem);
> + zswap_pool_put(entry->pool);
> +freepage:
> zswap_entry_cache_free(entry);
> reject:
> return ret;
> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> {
> struct zswap_tree *tree = zswap_trees[type];
> struct zswap_entry *entry;
> + struct crypto_comp *tfm;
> u8 *src, *dst;
> unsigned int dlen;
> int ret;
> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>
> /* decompress */
> dlen = PAGE_SIZE;
> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> dst = kmap_atomic(page);
> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> - dst, &dlen);
> + tfm = *get_cpu_ptr(entry->pool->tfm);
> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> + put_cpu_ptr(entry->pool->tfm);
> kunmap_atomic(dst);
> - zpool_unmap_handle(zswap_pool, entry->handle);
> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> BUG_ON(ret);
>
> spin_lock(&tree->lock);
> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> zswap_trees[type] = NULL;
> }
>
> -static struct zpool_ops zswap_zpool_ops = {
> - .evict = zswap_writeback_entry
> -};
> -
> static void zswap_frontswap_init(unsigned type)
> {
> struct zswap_tree *tree;
> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> **********************************/
> static int __init init_zswap(void)
> {
> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> + struct zswap_pool *pool;
>
> - pr_info("loading zswap\n");
> -
> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> - &zswap_zpool_ops);
> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> - pr_info("%s zpool not available\n", zswap_zpool_type);
> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> - &zswap_zpool_ops);
> - }
> - if (!zswap_pool) {
> - pr_err("%s zpool not available\n", zswap_zpool_type);
> - pr_err("zpool creation failed\n");
> - goto error;
> - }
> - pr_info("using %s pool\n", zswap_zpool_type);
> + pr_info("loading\n");
>
> if (zswap_entry_cache_create()) {
> pr_err("entry cache creation failed\n");
> - goto cachefail;
> + goto cache_fail;
> }
> - if (zswap_comp_init()) {
> - pr_err("compressor initialization failed\n");
> - goto compfail;
> +
> + if (zswap_cpu_dstmem_init()) {
> + pr_err("dstmem alloc failed\n");
> + goto dstmem_fail;
> }
> - if (zswap_cpu_init()) {
> - pr_err("per-cpu initialization failed\n");
> - goto pcpufail;
> +
> + pool = __zswap_pool_create_fallback();
> + if (!pool) {
> + pr_err("pool creation failed\n");
> + goto pool_fail;
> }
> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> + zpool_get_type(pool->zpool));
> +
> + list_add(&pool->list, &zswap_pools);
>
> frontswap_register_ops(&zswap_frontswap_ops);
> if (zswap_debugfs_init())
> pr_warn("debugfs initialization failed\n");
> return 0;
> -pcpufail:
> - zswap_comp_exit();
> -compfail:
> +
> +pool_fail:
> + zswap_cpu_dstmem_destroy();
> +dstmem_fail:
> zswap_entry_cache_destroy();
> -cachefail:
> - zpool_destroy_pool(zswap_pool);
> -error:
> +cache_fail:
> return -ENOMEM;
> }
> /* must be late so crypto has time to come up */
> --
> 2.1.0
>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-04 12:13 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-04 12:13 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> Add dynamic creation of pools. Move the static crypto compression
> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> the pool it's in.
Seth, as far as the design, from your previous comments I assume you
were thinking of maintaining separate lists of zpools and compressors?
I do see how that will reduce duplication of zpools and compressors,
but it also requires adding a new pointer to each zswap_entry, and
increasing the amount of code to manage each list separately. And the
most common case in zswap will be just a single zpool and compressor,
not repeatedly changing params. What do you think?
>
> This is required by a separate patch which enables changing the
> zswap zpool and compressor params at runtime.
>
> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> ---
> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 408 insertions(+), 142 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 2d5727b..fc93770 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> static struct zpool *zswap_pool;
>
> /*********************************
> -* compression functions
> +* data structures
> **********************************/
> -/* per-cpu compression transforms */
> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>
> -enum comp_op {
> - ZSWAP_COMPOP_COMPRESS,
> - ZSWAP_COMPOP_DECOMPRESS
> +struct zswap_pool {
> + struct zpool *zpool;
> + struct kref kref;
> + struct list_head list;
> + struct rcu_head rcu_head;
> + struct notifier_block notifier;
> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> + struct crypto_comp * __percpu *tfm;
> };
>
> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> - u8 *dst, unsigned int *dlen)
> -{
> - struct crypto_comp *tfm;
> - int ret;
> -
> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> - switch (op) {
> - case ZSWAP_COMPOP_COMPRESS:
> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> - break;
> - case ZSWAP_COMPOP_DECOMPRESS:
> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> - break;
> - default:
> - ret = -EINVAL;
> - }
> -
> - put_cpu();
> - return ret;
> -}
> -
> -static int __init zswap_comp_init(void)
> -{
> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> - pr_info("%s compressor not available\n", zswap_compressor);
> - /* fall back to default compressor */
> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> - /* can't even load the default compressor */
> - return -ENODEV;
> - }
> - pr_info("using %s compressor\n", zswap_compressor);
> -
> - /* alloc percpu transforms */
> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> - if (!zswap_comp_pcpu_tfms)
> - return -ENOMEM;
> - return 0;
> -}
> -
> -static void __init zswap_comp_exit(void)
> -{
> - /* free percpu transforms */
> - free_percpu(zswap_comp_pcpu_tfms);
> -}
> -
> -/*********************************
> -* data structures
> -**********************************/
> /*
> * struct zswap_entry
> *
> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> * page within zswap.
> *
> * rbnode - links the entry into red-black tree for the appropriate swap type
> + * offset - the swap offset for the entry. Index into the red-black tree.
> * refcount - the number of outstanding reference to the entry. This is needed
> * to protect against premature freeing of the entry by code
> * concurrent calls to load, invalidate, and writeback. The lock
> * for the zswap_tree structure that contains the entry must
> * be held while changing the refcount. Since the lock must
> * be held, there is no reason to also make refcount atomic.
> - * offset - the swap offset for the entry. Index into the red-black tree.
> - * handle - zpool allocation handle that stores the compressed page data
> * length - the length in bytes of the compressed page data. Needed during
> * decompression
> + * pool - the zswap_pool the entry's data is in
> + * handle - zpool allocation handle that stores the compressed page data
> */
> struct zswap_entry {
> struct rb_node rbnode;
> pgoff_t offset;
> int refcount;
> unsigned int length;
> + struct zswap_pool *pool;
> unsigned long handle;
> };
>
> @@ -201,6 +156,44 @@ struct zswap_tree {
>
> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>
> +/* RCU-protected iteration */
> +static LIST_HEAD(zswap_pools);
> +/* protects zswap_pools list modification */
> +static DEFINE_SPINLOCK(zswap_pools_lock);
> +
> +/*********************************
> +* helpers and fwd declarations
> +**********************************/
> +
> +#define zswap_pool_debug(msg, p) \
> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> + zpool_get_type((p)->zpool))
> +
> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> +static int zswap_pool_get(struct zswap_pool *pool);
> +static void zswap_pool_put(struct zswap_pool *pool);
> +
> +static bool zswap_is_full(void)
> +{
> + return totalram_pages * zswap_max_pool_percent / 100 <
> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> +}
> +
> +static void zswap_update_total_size(void)
> +{
> + struct zswap_pool *pool;
> + u64 total = 0;
> +
> + rcu_read_lock();
> +
> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> + total += zpool_get_total_size(pool->zpool);
> +
> + rcu_read_unlock();
> +
> + zswap_pool_total_size = total;
> +}
> +
> /*********************************
> * zswap entry functions
> **********************************/
> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> */
> static void zswap_free_entry(struct zswap_entry *entry)
> {
> - zpool_free(zswap_pool, entry->handle);
> + zpool_free(entry->pool->zpool, entry->handle);
> + zswap_pool_put(entry->pool);
> zswap_entry_cache_free(entry);
> atomic_dec(&zswap_stored_pages);
> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> + zswap_update_total_size();
> }
>
> /* caller must hold the tree lock */
> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> **********************************/
> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>
> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> {
> - struct crypto_comp *tfm;
> u8 *dst;
>
> switch (action) {
> case CPU_UP_PREPARE:
> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> - if (IS_ERR(tfm)) {
> - pr_err("can't allocate compressor transform\n");
> - return NOTIFY_BAD;
> - }
> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> if (!dst) {
> pr_err("can't allocate compressor buffer\n");
> - crypto_free_comp(tfm);
> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> return NOTIFY_BAD;
> }
> per_cpu(zswap_dstmem, cpu) = dst;
> break;
> case CPU_DEAD:
> case CPU_UP_CANCELED:
> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> - if (tfm) {
> - crypto_free_comp(tfm);
> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> - }
> dst = per_cpu(zswap_dstmem, cpu);
> kfree(dst);
> per_cpu(zswap_dstmem, cpu) = NULL;
> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> return NOTIFY_OK;
> }
>
> -static int zswap_cpu_notifier(struct notifier_block *nb,
> - unsigned long action, void *pcpu)
> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> + unsigned long action, void *pcpu)
> {
> - unsigned long cpu = (unsigned long)pcpu;
> - return __zswap_cpu_notifier(action, cpu);
> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> }
>
> -static struct notifier_block zswap_cpu_notifier_block = {
> - .notifier_call = zswap_cpu_notifier
> +static struct notifier_block zswap_dstmem_notifier = {
> + .notifier_call = zswap_cpu_dstmem_notifier,
> };
>
> -static int __init zswap_cpu_init(void)
> +static int __init zswap_cpu_dstmem_init(void)
> {
> unsigned long cpu;
>
> cpu_notifier_register_begin();
> for_each_online_cpu(cpu)
> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> + NOTIFY_BAD)
> goto cleanup;
> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> + __register_cpu_notifier(&zswap_dstmem_notifier);
> cpu_notifier_register_done();
> return 0;
>
> cleanup:
> for_each_online_cpu(cpu)
> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> cpu_notifier_register_done();
> return -ENOMEM;
> }
>
> +static void zswap_cpu_dstmem_destroy(void)
> +{
> + unsigned long cpu;
> +
> + cpu_notifier_register_begin();
> + for_each_online_cpu(cpu)
> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> + cpu_notifier_register_done();
> +}
> +
> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> + unsigned long action, unsigned long cpu)
> +{
> + struct crypto_comp *tfm;
> +
> + switch (action) {
> + case CPU_UP_PREPARE:
> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> + break;
> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> + if (IS_ERR_OR_NULL(tfm)) {
> + pr_err("could not alloc crypto comp %s : %ld\n",
> + pool->tfm_name, PTR_ERR(tfm));
> + return NOTIFY_BAD;
> + }
> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> + break;
> + case CPU_DEAD:
> + case CPU_UP_CANCELED:
> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> + if (!IS_ERR_OR_NULL(tfm))
> + crypto_free_comp(tfm);
> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> + break;
> + default:
> + break;
> + }
> + return NOTIFY_OK;
> +}
> +
> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> + unsigned long action, void *pcpu)
> +{
> + unsigned long cpu = (unsigned long)pcpu;
> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> +
> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> +}
> +
> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> +{
> + unsigned long cpu;
> +
> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> +
> + cpu_notifier_register_begin();
> + for_each_online_cpu(cpu)
> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> + NOTIFY_BAD)
> + goto cleanup;
> + __register_cpu_notifier(&pool->notifier);
> + cpu_notifier_register_done();
> + return 0;
> +
> +cleanup:
> + for_each_online_cpu(cpu)
> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> + cpu_notifier_register_done();
> + return -ENOMEM;
> +}
> +
> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> +{
> + unsigned long cpu;
> +
> + cpu_notifier_register_begin();
> + for_each_online_cpu(cpu)
> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> + __unregister_cpu_notifier(&pool->notifier);
> + cpu_notifier_register_done();
> +}
> +
> /*********************************
> -* helpers
> +* pool functions
> **********************************/
> -static bool zswap_is_full(void)
> +
> +static struct zswap_pool *__zswap_pool_current(void)
> {
> - return totalram_pages * zswap_max_pool_percent / 100 <
> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> + struct zswap_pool *pool;
> +
> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> + WARN_ON(!pool);
> +
> + return pool;
> +}
> +
> +static struct zswap_pool *zswap_pool_current(void)
> +{
> + assert_spin_locked(&zswap_pools_lock);
> +
> + return __zswap_pool_current();
> +}
> +
> +static struct zswap_pool *zswap_pool_current_get(void)
> +{
> + struct zswap_pool *pool;
> +
> + rcu_read_lock();
> +
> + pool = __zswap_pool_current();
> + if (!pool || !zswap_pool_get(pool))
> + pool = NULL;
> +
> + rcu_read_unlock();
> +
> + return pool;
> +}
> +
> +static struct zswap_pool *zswap_pool_last_get(void)
> +{
> + struct zswap_pool *pool, *last = NULL;
> +
> + rcu_read_lock();
> +
> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> + last = pool;
> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> + last = NULL;
> +
> + rcu_read_unlock();
> +
> + return last;
> +}
> +
> +static struct zpool_ops zswap_zpool_ops = {
> + .evict = zswap_writeback_entry
> +};
> +
> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> +{
> + struct zswap_pool *pool;
> +
> + assert_spin_locked(&zswap_pools_lock);
> +
> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> + continue;
> + if (strncmp(zpool_get_type(pool->zpool), type,
> + sizeof(zswap_zpool_type)))
> + continue;
> + /* if we can't get it, it's about to be destroyed */
> + if (!zswap_pool_get(pool))
> + continue;
> + return pool;
> + }
> +
> + return NULL;
> +}
> +
> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> +{
> + struct zswap_pool *pool;
> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> +
> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> + if (!pool) {
> + pr_err("pool alloc failed\n");
> + return NULL;
> + }
> +
> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> + if (!pool->zpool) {
> + pr_err("%s zpool not available\n", type);
> + goto error;
> + }
> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> +
> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> + pool->tfm = alloc_percpu(struct crypto_comp *);
> + if (!pool->tfm) {
> + pr_err("percpu alloc failed\n");
> + goto error;
> + }
> +
> + if (zswap_cpu_comp_init(pool))
> + goto error;
> + pr_debug("using %s compressor\n", pool->tfm_name);
> +
> + /* being the current pool takes 1 ref; this func expects the
> + * caller to always add the new pool as the current pool
> + */
> + kref_init(&pool->kref);
> + INIT_LIST_HEAD(&pool->list);
> +
> + zswap_pool_debug("created", pool);
> +
> + return pool;
> +
> +error:
> + free_percpu(pool->tfm);
> + if (pool->zpool)
> + zpool_destroy_pool(pool->zpool);
> + kfree(pool);
> + return NULL;
> +}
> +
> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> +{
> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> + pr_err("compressor %s not available, using default %s\n",
> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> + sizeof(zswap_compressor));
> + }
> + if (!zpool_has_pool(zswap_zpool_type)) {
> + pr_err("zpool %s not available, using default %s\n",
> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> + sizeof(zswap_zpool_type));
> + }
> +
> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> +}
> +
> +static void zswap_pool_destroy(struct zswap_pool *pool)
> +{
> + zswap_pool_debug("destroying", pool);
> +
> + zswap_cpu_comp_destroy(pool);
> + free_percpu(pool->tfm);
> + zpool_destroy_pool(pool->zpool);
> + kfree(pool);
> +}
> +
> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> +{
> + return kref_get_unless_zero(&pool->kref);
> +}
> +
> +static void __zswap_pool_release(struct rcu_head *head)
> +{
> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> +
> + /* nobody should have been able to get a kref... */
> + WARN_ON(kref_get_unless_zero(&pool->kref));
> +
> + /* pool is now off zswap_pools list and has no references. */
> + zswap_pool_destroy(pool);
> +}
> +
> +static void __zswap_pool_empty(struct kref *kref)
> +{
> + struct zswap_pool *pool;
> +
> + pool = container_of(kref, typeof(*pool), kref);
> +
> + spin_lock(&zswap_pools_lock);
> +
> + WARN_ON(pool == zswap_pool_current());
> +
> + list_del_rcu(&pool->list);
> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> +
> + spin_unlock(&zswap_pools_lock);
> +}
> +
> +static void zswap_pool_put(struct zswap_pool *pool)
> +{
> + kref_put(&pool->kref, __zswap_pool_empty);
> +}
> +
> }
>
> /*********************************
> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> pgoff_t offset;
> struct zswap_entry *entry;
> struct page *page;
> + struct crypto_comp *tfm;
> u8 *src, *dst;
> unsigned int dlen;
> int ret;
> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> /* decompress */
> dlen = PAGE_SIZE;
> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> dst = kmap_atomic(page);
> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> - entry->length, dst, &dlen);
> + tfm = *get_cpu_ptr(entry->pool->tfm);
> + ret = crypto_comp_decompress(tfm, src, entry->length,
> + dst, &dlen);
> + put_cpu_ptr(entry->pool->tfm);
> kunmap_atomic(dst);
> - zpool_unmap_handle(zswap_pool, entry->handle);
> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> BUG_ON(ret);
> BUG_ON(dlen != PAGE_SIZE);
>
> @@ -633,6 +882,22 @@ end:
> return ret;
> }
>
> +static int zswap_shrink(void)
> +{
> + struct zswap_pool *pool;
> + int ret;
> +
> + pool = zswap_pool_last_get();
> + if (!pool)
> + return -ENOENT;
> +
> + ret = zpool_shrink(pool->zpool, 1, NULL);
> +
> + zswap_pool_put(pool);
> +
> + return ret;
> +}
> +
> /*********************************
> * frontswap hooks
> **********************************/
> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> {
> struct zswap_tree *tree = zswap_trees[type];
> struct zswap_entry *entry, *dupentry;
> + struct crypto_comp *tfm;
> int ret;
> unsigned int dlen = PAGE_SIZE, len;
> unsigned long handle;
> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> /* reclaim space if needed */
> if (zswap_is_full()) {
> zswap_pool_limit_hit++;
> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> + if (zswap_shrink()) {
> zswap_reject_reclaim_fail++;
> ret = -ENOMEM;
> goto reject;
> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> goto reject;
> }
>
> + /* if entry is successfully added, it keeps the reference */
> + entry->pool = zswap_pool_current_get();
> + if (!entry->pool) {
> + ret = -EINVAL;
> + goto freepage;
> + }
> +
> /* compress */
> dst = get_cpu_var(zswap_dstmem);
> + tfm = *get_cpu_ptr(entry->pool->tfm);
> src = kmap_atomic(page);
> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> kunmap_atomic(src);
> + put_cpu_ptr(entry->pool->tfm);
> if (ret) {
> ret = -EINVAL;
> - goto freepage;
> + goto put_dstmem;
> }
>
> /* store */
> len = dlen + sizeof(struct zswap_header);
> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> - &handle);
> + ret = zpool_malloc(entry->pool->zpool, len,
> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> if (ret == -ENOSPC) {
> zswap_reject_compress_poor++;
> - goto freepage;
> + goto put_dstmem;
> }
> if (ret) {
> zswap_reject_alloc_fail++;
> - goto freepage;
> + goto put_dstmem;
> }
> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> zhdr->swpentry = swp_entry(type, offset);
> buf = (u8 *)(zhdr + 1);
> memcpy(buf, dst, dlen);
> - zpool_unmap_handle(zswap_pool, handle);
> + zpool_unmap_handle(entry->pool->zpool, handle);
> put_cpu_var(zswap_dstmem);
>
> /* populate entry */
> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>
> /* update stats */
> atomic_inc(&zswap_stored_pages);
> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> + zswap_update_total_size();
>
> return 0;
>
> -freepage:
> +put_dstmem:
> put_cpu_var(zswap_dstmem);
> + zswap_pool_put(entry->pool);
> +freepage:
> zswap_entry_cache_free(entry);
> reject:
> return ret;
> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> {
> struct zswap_tree *tree = zswap_trees[type];
> struct zswap_entry *entry;
> + struct crypto_comp *tfm;
> u8 *src, *dst;
> unsigned int dlen;
> int ret;
> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>
> /* decompress */
> dlen = PAGE_SIZE;
> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> dst = kmap_atomic(page);
> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> - dst, &dlen);
> + tfm = *get_cpu_ptr(entry->pool->tfm);
> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> + put_cpu_ptr(entry->pool->tfm);
> kunmap_atomic(dst);
> - zpool_unmap_handle(zswap_pool, entry->handle);
> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> BUG_ON(ret);
>
> spin_lock(&tree->lock);
> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> zswap_trees[type] = NULL;
> }
>
> -static struct zpool_ops zswap_zpool_ops = {
> - .evict = zswap_writeback_entry
> -};
> -
> static void zswap_frontswap_init(unsigned type)
> {
> struct zswap_tree *tree;
> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> **********************************/
> static int __init init_zswap(void)
> {
> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> + struct zswap_pool *pool;
>
> - pr_info("loading zswap\n");
> -
> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> - &zswap_zpool_ops);
> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> - pr_info("%s zpool not available\n", zswap_zpool_type);
> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> - &zswap_zpool_ops);
> - }
> - if (!zswap_pool) {
> - pr_err("%s zpool not available\n", zswap_zpool_type);
> - pr_err("zpool creation failed\n");
> - goto error;
> - }
> - pr_info("using %s pool\n", zswap_zpool_type);
> + pr_info("loading\n");
>
> if (zswap_entry_cache_create()) {
> pr_err("entry cache creation failed\n");
> - goto cachefail;
> + goto cache_fail;
> }
> - if (zswap_comp_init()) {
> - pr_err("compressor initialization failed\n");
> - goto compfail;
> +
> + if (zswap_cpu_dstmem_init()) {
> + pr_err("dstmem alloc failed\n");
> + goto dstmem_fail;
> }
> - if (zswap_cpu_init()) {
> - pr_err("per-cpu initialization failed\n");
> - goto pcpufail;
> +
> + pool = __zswap_pool_create_fallback();
> + if (!pool) {
> + pr_err("pool creation failed\n");
> + goto pool_fail;
> }
> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> + zpool_get_type(pool->zpool));
> +
> + list_add(&pool->list, &zswap_pools);
>
> frontswap_register_ops(&zswap_frontswap_ops);
> if (zswap_debugfs_init())
> pr_warn("debugfs initialization failed\n");
> return 0;
> -pcpufail:
> - zswap_comp_exit();
> -compfail:
> +
> +pool_fail:
> + zswap_cpu_dstmem_destroy();
> +dstmem_fail:
> zswap_entry_cache_destroy();
> -cachefail:
> - zpool_destroy_pool(zswap_pool);
> -error:
> +cache_fail:
> return -ENOMEM;
> }
> /* must be late so crypto has time to come up */
> --
> 2.1.0
>
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-04 12:13 ` Dan Streetman
@ 2015-06-10 20:54 ` Dan Streetman
-1 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-10 20:54 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>> Add dynamic creation of pools. Move the static crypto compression
>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
>> the pool it's in.
>
> Seth, as far as the design, from your previous comments I assume you
> were thinking of maintaining separate lists of zpools and compressors?
> I do see how that will reduce duplication of zpools and compressors,
> but it also requires adding a new pointer to each zswap_entry, and
> increasing the amount of code to manage each list separately. And the
> most common case in zswap will be just a single zpool and compressor,
> not repeatedly changing params. What do you think?
Any opinion on this patch? If you want, I can break it up so there's
a list of zpools and a list of compressors. Either the combined way
(this patch) or separate lists works for me, as long as the params are
changeable at runtime :-)
>
>>
>> This is required by a separate patch which enables changing the
>> zswap zpool and compressor params at runtime.
>>
>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
>> ---
>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
>> 1 file changed, 408 insertions(+), 142 deletions(-)
>>
>> diff --git a/mm/zswap.c b/mm/zswap.c
>> index 2d5727b..fc93770 100644
>> --- a/mm/zswap.c
>> +++ b/mm/zswap.c
>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
>> static struct zpool *zswap_pool;
>>
>> /*********************************
>> -* compression functions
>> +* data structures
>> **********************************/
>> -/* per-cpu compression transforms */
>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>>
>> -enum comp_op {
>> - ZSWAP_COMPOP_COMPRESS,
>> - ZSWAP_COMPOP_DECOMPRESS
>> +struct zswap_pool {
>> + struct zpool *zpool;
>> + struct kref kref;
>> + struct list_head list;
>> + struct rcu_head rcu_head;
>> + struct notifier_block notifier;
>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
>> + struct crypto_comp * __percpu *tfm;
>> };
>>
>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
>> - u8 *dst, unsigned int *dlen)
>> -{
>> - struct crypto_comp *tfm;
>> - int ret;
>> -
>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
>> - switch (op) {
>> - case ZSWAP_COMPOP_COMPRESS:
>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
>> - break;
>> - case ZSWAP_COMPOP_DECOMPRESS:
>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
>> - break;
>> - default:
>> - ret = -EINVAL;
>> - }
>> -
>> - put_cpu();
>> - return ret;
>> -}
>> -
>> -static int __init zswap_comp_init(void)
>> -{
>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>> - pr_info("%s compressor not available\n", zswap_compressor);
>> - /* fall back to default compressor */
>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
>> - /* can't even load the default compressor */
>> - return -ENODEV;
>> - }
>> - pr_info("using %s compressor\n", zswap_compressor);
>> -
>> - /* alloc percpu transforms */
>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
>> - if (!zswap_comp_pcpu_tfms)
>> - return -ENOMEM;
>> - return 0;
>> -}
>> -
>> -static void __init zswap_comp_exit(void)
>> -{
>> - /* free percpu transforms */
>> - free_percpu(zswap_comp_pcpu_tfms);
>> -}
>> -
>> -/*********************************
>> -* data structures
>> -**********************************/
>> /*
>> * struct zswap_entry
>> *
>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
>> * page within zswap.
>> *
>> * rbnode - links the entry into red-black tree for the appropriate swap type
>> + * offset - the swap offset for the entry. Index into the red-black tree.
>> * refcount - the number of outstanding reference to the entry. This is needed
>> * to protect against premature freeing of the entry by code
>> * concurrent calls to load, invalidate, and writeback. The lock
>> * for the zswap_tree structure that contains the entry must
>> * be held while changing the refcount. Since the lock must
>> * be held, there is no reason to also make refcount atomic.
>> - * offset - the swap offset for the entry. Index into the red-black tree.
>> - * handle - zpool allocation handle that stores the compressed page data
>> * length - the length in bytes of the compressed page data. Needed during
>> * decompression
>> + * pool - the zswap_pool the entry's data is in
>> + * handle - zpool allocation handle that stores the compressed page data
>> */
>> struct zswap_entry {
>> struct rb_node rbnode;
>> pgoff_t offset;
>> int refcount;
>> unsigned int length;
>> + struct zswap_pool *pool;
>> unsigned long handle;
>> };
>>
>> @@ -201,6 +156,44 @@ struct zswap_tree {
>>
>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>>
>> +/* RCU-protected iteration */
>> +static LIST_HEAD(zswap_pools);
>> +/* protects zswap_pools list modification */
>> +static DEFINE_SPINLOCK(zswap_pools_lock);
>> +
>> +/*********************************
>> +* helpers and fwd declarations
>> +**********************************/
>> +
>> +#define zswap_pool_debug(msg, p) \
>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
>> + zpool_get_type((p)->zpool))
>> +
>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
>> +static int zswap_pool_get(struct zswap_pool *pool);
>> +static void zswap_pool_put(struct zswap_pool *pool);
>> +
>> +static bool zswap_is_full(void)
>> +{
>> + return totalram_pages * zswap_max_pool_percent / 100 <
>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>> +}
>> +
>> +static void zswap_update_total_size(void)
>> +{
>> + struct zswap_pool *pool;
>> + u64 total = 0;
>> +
>> + rcu_read_lock();
>> +
>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>> + total += zpool_get_total_size(pool->zpool);
>> +
>> + rcu_read_unlock();
>> +
>> + zswap_pool_total_size = total;
>> +}
>> +
>> /*********************************
>> * zswap entry functions
>> **********************************/
>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
>> */
>> static void zswap_free_entry(struct zswap_entry *entry)
>> {
>> - zpool_free(zswap_pool, entry->handle);
>> + zpool_free(entry->pool->zpool, entry->handle);
>> + zswap_pool_put(entry->pool);
>> zswap_entry_cache_free(entry);
>> atomic_dec(&zswap_stored_pages);
>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>> + zswap_update_total_size();
>> }
>>
>> /* caller must hold the tree lock */
>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
>> **********************************/
>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>>
>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
>> {
>> - struct crypto_comp *tfm;
>> u8 *dst;
>>
>> switch (action) {
>> case CPU_UP_PREPARE:
>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
>> - if (IS_ERR(tfm)) {
>> - pr_err("can't allocate compressor transform\n");
>> - return NOTIFY_BAD;
>> - }
>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
>> if (!dst) {
>> pr_err("can't allocate compressor buffer\n");
>> - crypto_free_comp(tfm);
>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>> return NOTIFY_BAD;
>> }
>> per_cpu(zswap_dstmem, cpu) = dst;
>> break;
>> case CPU_DEAD:
>> case CPU_UP_CANCELED:
>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
>> - if (tfm) {
>> - crypto_free_comp(tfm);
>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>> - }
>> dst = per_cpu(zswap_dstmem, cpu);
>> kfree(dst);
>> per_cpu(zswap_dstmem, cpu) = NULL;
>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>> return NOTIFY_OK;
>> }
>>
>> -static int zswap_cpu_notifier(struct notifier_block *nb,
>> - unsigned long action, void *pcpu)
>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
>> + unsigned long action, void *pcpu)
>> {
>> - unsigned long cpu = (unsigned long)pcpu;
>> - return __zswap_cpu_notifier(action, cpu);
>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
>> }
>>
>> -static struct notifier_block zswap_cpu_notifier_block = {
>> - .notifier_call = zswap_cpu_notifier
>> +static struct notifier_block zswap_dstmem_notifier = {
>> + .notifier_call = zswap_cpu_dstmem_notifier,
>> };
>>
>> -static int __init zswap_cpu_init(void)
>> +static int __init zswap_cpu_dstmem_init(void)
>> {
>> unsigned long cpu;
>>
>> cpu_notifier_register_begin();
>> for_each_online_cpu(cpu)
>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
>> + NOTIFY_BAD)
>> goto cleanup;
>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
>> + __register_cpu_notifier(&zswap_dstmem_notifier);
>> cpu_notifier_register_done();
>> return 0;
>>
>> cleanup:
>> for_each_online_cpu(cpu)
>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>> cpu_notifier_register_done();
>> return -ENOMEM;
>> }
>>
>> +static void zswap_cpu_dstmem_destroy(void)
>> +{
>> + unsigned long cpu;
>> +
>> + cpu_notifier_register_begin();
>> + for_each_online_cpu(cpu)
>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
>> + cpu_notifier_register_done();
>> +}
>> +
>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
>> + unsigned long action, unsigned long cpu)
>> +{
>> + struct crypto_comp *tfm;
>> +
>> + switch (action) {
>> + case CPU_UP_PREPARE:
>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
>> + break;
>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
>> + if (IS_ERR_OR_NULL(tfm)) {
>> + pr_err("could not alloc crypto comp %s : %ld\n",
>> + pool->tfm_name, PTR_ERR(tfm));
>> + return NOTIFY_BAD;
>> + }
>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
>> + break;
>> + case CPU_DEAD:
>> + case CPU_UP_CANCELED:
>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
>> + if (!IS_ERR_OR_NULL(tfm))
>> + crypto_free_comp(tfm);
>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
>> + break;
>> + default:
>> + break;
>> + }
>> + return NOTIFY_OK;
>> +}
>> +
>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
>> + unsigned long action, void *pcpu)
>> +{
>> + unsigned long cpu = (unsigned long)pcpu;
>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
>> +
>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
>> +}
>> +
>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
>> +{
>> + unsigned long cpu;
>> +
>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
>> +
>> + cpu_notifier_register_begin();
>> + for_each_online_cpu(cpu)
>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
>> + NOTIFY_BAD)
>> + goto cleanup;
>> + __register_cpu_notifier(&pool->notifier);
>> + cpu_notifier_register_done();
>> + return 0;
>> +
>> +cleanup:
>> + for_each_online_cpu(cpu)
>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>> + cpu_notifier_register_done();
>> + return -ENOMEM;
>> +}
>> +
>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
>> +{
>> + unsigned long cpu;
>> +
>> + cpu_notifier_register_begin();
>> + for_each_online_cpu(cpu)
>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>> + __unregister_cpu_notifier(&pool->notifier);
>> + cpu_notifier_register_done();
>> +}
>> +
>> /*********************************
>> -* helpers
>> +* pool functions
>> **********************************/
>> -static bool zswap_is_full(void)
>> +
>> +static struct zswap_pool *__zswap_pool_current(void)
>> {
>> - return totalram_pages * zswap_max_pool_percent / 100 <
>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>> + struct zswap_pool *pool;
>> +
>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
>> + WARN_ON(!pool);
>> +
>> + return pool;
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_current(void)
>> +{
>> + assert_spin_locked(&zswap_pools_lock);
>> +
>> + return __zswap_pool_current();
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_current_get(void)
>> +{
>> + struct zswap_pool *pool;
>> +
>> + rcu_read_lock();
>> +
>> + pool = __zswap_pool_current();
>> + if (!pool || !zswap_pool_get(pool))
>> + pool = NULL;
>> +
>> + rcu_read_unlock();
>> +
>> + return pool;
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_last_get(void)
>> +{
>> + struct zswap_pool *pool, *last = NULL;
>> +
>> + rcu_read_lock();
>> +
>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>> + last = pool;
>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
>> + last = NULL;
>> +
>> + rcu_read_unlock();
>> +
>> + return last;
>> +}
>> +
>> +static struct zpool_ops zswap_zpool_ops = {
>> + .evict = zswap_writeback_entry
>> +};
>> +
>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
>> +{
>> + struct zswap_pool *pool;
>> +
>> + assert_spin_locked(&zswap_pools_lock);
>> +
>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
>> + continue;
>> + if (strncmp(zpool_get_type(pool->zpool), type,
>> + sizeof(zswap_zpool_type)))
>> + continue;
>> + /* if we can't get it, it's about to be destroyed */
>> + if (!zswap_pool_get(pool))
>> + continue;
>> + return pool;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
>> +{
>> + struct zswap_pool *pool;
>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>> +
>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
>> + if (!pool) {
>> + pr_err("pool alloc failed\n");
>> + return NULL;
>> + }
>> +
>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
>> + if (!pool->zpool) {
>> + pr_err("%s zpool not available\n", type);
>> + goto error;
>> + }
>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
>> +
>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
>> + pool->tfm = alloc_percpu(struct crypto_comp *);
>> + if (!pool->tfm) {
>> + pr_err("percpu alloc failed\n");
>> + goto error;
>> + }
>> +
>> + if (zswap_cpu_comp_init(pool))
>> + goto error;
>> + pr_debug("using %s compressor\n", pool->tfm_name);
>> +
>> + /* being the current pool takes 1 ref; this func expects the
>> + * caller to always add the new pool as the current pool
>> + */
>> + kref_init(&pool->kref);
>> + INIT_LIST_HEAD(&pool->list);
>> +
>> + zswap_pool_debug("created", pool);
>> +
>> + return pool;
>> +
>> +error:
>> + free_percpu(pool->tfm);
>> + if (pool->zpool)
>> + zpool_destroy_pool(pool->zpool);
>> + kfree(pool);
>> + return NULL;
>> +}
>> +
>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
>> +{
>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>> + pr_err("compressor %s not available, using default %s\n",
>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
>> + sizeof(zswap_compressor));
>> + }
>> + if (!zpool_has_pool(zswap_zpool_type)) {
>> + pr_err("zpool %s not available, using default %s\n",
>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
>> + sizeof(zswap_zpool_type));
>> + }
>> +
>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
>> +}
>> +
>> +static void zswap_pool_destroy(struct zswap_pool *pool)
>> +{
>> + zswap_pool_debug("destroying", pool);
>> +
>> + zswap_cpu_comp_destroy(pool);
>> + free_percpu(pool->tfm);
>> + zpool_destroy_pool(pool->zpool);
>> + kfree(pool);
>> +}
>> +
>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
>> +{
>> + return kref_get_unless_zero(&pool->kref);
>> +}
>> +
>> +static void __zswap_pool_release(struct rcu_head *head)
>> +{
>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
>> +
>> + /* nobody should have been able to get a kref... */
>> + WARN_ON(kref_get_unless_zero(&pool->kref));
>> +
>> + /* pool is now off zswap_pools list and has no references. */
>> + zswap_pool_destroy(pool);
>> +}
>> +
>> +static void __zswap_pool_empty(struct kref *kref)
>> +{
>> + struct zswap_pool *pool;
>> +
>> + pool = container_of(kref, typeof(*pool), kref);
>> +
>> + spin_lock(&zswap_pools_lock);
>> +
>> + WARN_ON(pool == zswap_pool_current());
>> +
>> + list_del_rcu(&pool->list);
>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
>> +
>> + spin_unlock(&zswap_pools_lock);
>> +}
>> +
>> +static void zswap_pool_put(struct zswap_pool *pool)
>> +{
>> + kref_put(&pool->kref, __zswap_pool_empty);
>> +}
>> +
>> }
>>
>> /*********************************
>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>> pgoff_t offset;
>> struct zswap_entry *entry;
>> struct page *page;
>> + struct crypto_comp *tfm;
>> u8 *src, *dst;
>> unsigned int dlen;
>> int ret;
>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
>> /* decompress */
>> dlen = PAGE_SIZE;
>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>> dst = kmap_atomic(page);
>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
>> - entry->length, dst, &dlen);
>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>> + ret = crypto_comp_decompress(tfm, src, entry->length,
>> + dst, &dlen);
>> + put_cpu_ptr(entry->pool->tfm);
>> kunmap_atomic(dst);
>> - zpool_unmap_handle(zswap_pool, entry->handle);
>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>> BUG_ON(ret);
>> BUG_ON(dlen != PAGE_SIZE);
>>
>> @@ -633,6 +882,22 @@ end:
>> return ret;
>> }
>>
>> +static int zswap_shrink(void)
>> +{
>> + struct zswap_pool *pool;
>> + int ret;
>> +
>> + pool = zswap_pool_last_get();
>> + if (!pool)
>> + return -ENOENT;
>> +
>> + ret = zpool_shrink(pool->zpool, 1, NULL);
>> +
>> + zswap_pool_put(pool);
>> +
>> + return ret;
>> +}
>> +
>> /*********************************
>> * frontswap hooks
>> **********************************/
>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>> {
>> struct zswap_tree *tree = zswap_trees[type];
>> struct zswap_entry *entry, *dupentry;
>> + struct crypto_comp *tfm;
>> int ret;
>> unsigned int dlen = PAGE_SIZE, len;
>> unsigned long handle;
>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>> /* reclaim space if needed */
>> if (zswap_is_full()) {
>> zswap_pool_limit_hit++;
>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
>> + if (zswap_shrink()) {
>> zswap_reject_reclaim_fail++;
>> ret = -ENOMEM;
>> goto reject;
>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>> goto reject;
>> }
>>
>> + /* if entry is successfully added, it keeps the reference */
>> + entry->pool = zswap_pool_current_get();
>> + if (!entry->pool) {
>> + ret = -EINVAL;
>> + goto freepage;
>> + }
>> +
>> /* compress */
>> dst = get_cpu_var(zswap_dstmem);
>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>> src = kmap_atomic(page);
>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
>> kunmap_atomic(src);
>> + put_cpu_ptr(entry->pool->tfm);
>> if (ret) {
>> ret = -EINVAL;
>> - goto freepage;
>> + goto put_dstmem;
>> }
>>
>> /* store */
>> len = dlen + sizeof(struct zswap_header);
>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
>> - &handle);
>> + ret = zpool_malloc(entry->pool->zpool, len,
>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
>> if (ret == -ENOSPC) {
>> zswap_reject_compress_poor++;
>> - goto freepage;
>> + goto put_dstmem;
>> }
>> if (ret) {
>> zswap_reject_alloc_fail++;
>> - goto freepage;
>> + goto put_dstmem;
>> }
>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
>> zhdr->swpentry = swp_entry(type, offset);
>> buf = (u8 *)(zhdr + 1);
>> memcpy(buf, dst, dlen);
>> - zpool_unmap_handle(zswap_pool, handle);
>> + zpool_unmap_handle(entry->pool->zpool, handle);
>> put_cpu_var(zswap_dstmem);
>>
>> /* populate entry */
>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>
>> /* update stats */
>> atomic_inc(&zswap_stored_pages);
>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>> + zswap_update_total_size();
>>
>> return 0;
>>
>> -freepage:
>> +put_dstmem:
>> put_cpu_var(zswap_dstmem);
>> + zswap_pool_put(entry->pool);
>> +freepage:
>> zswap_entry_cache_free(entry);
>> reject:
>> return ret;
>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>> {
>> struct zswap_tree *tree = zswap_trees[type];
>> struct zswap_entry *entry;
>> + struct crypto_comp *tfm;
>> u8 *src, *dst;
>> unsigned int dlen;
>> int ret;
>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>
>> /* decompress */
>> dlen = PAGE_SIZE;
>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>> dst = kmap_atomic(page);
>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
>> - dst, &dlen);
>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
>> + put_cpu_ptr(entry->pool->tfm);
>> kunmap_atomic(dst);
>> - zpool_unmap_handle(zswap_pool, entry->handle);
>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>> BUG_ON(ret);
>>
>> spin_lock(&tree->lock);
>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
>> zswap_trees[type] = NULL;
>> }
>>
>> -static struct zpool_ops zswap_zpool_ops = {
>> - .evict = zswap_writeback_entry
>> -};
>> -
>> static void zswap_frontswap_init(unsigned type)
>> {
>> struct zswap_tree *tree;
>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
>> **********************************/
>> static int __init init_zswap(void)
>> {
>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>> + struct zswap_pool *pool;
>>
>> - pr_info("loading zswap\n");
>> -
>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>> - &zswap_zpool_ops);
>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
>> - pr_info("%s zpool not available\n", zswap_zpool_type);
>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>> - &zswap_zpool_ops);
>> - }
>> - if (!zswap_pool) {
>> - pr_err("%s zpool not available\n", zswap_zpool_type);
>> - pr_err("zpool creation failed\n");
>> - goto error;
>> - }
>> - pr_info("using %s pool\n", zswap_zpool_type);
>> + pr_info("loading\n");
>>
>> if (zswap_entry_cache_create()) {
>> pr_err("entry cache creation failed\n");
>> - goto cachefail;
>> + goto cache_fail;
>> }
>> - if (zswap_comp_init()) {
>> - pr_err("compressor initialization failed\n");
>> - goto compfail;
>> +
>> + if (zswap_cpu_dstmem_init()) {
>> + pr_err("dstmem alloc failed\n");
>> + goto dstmem_fail;
>> }
>> - if (zswap_cpu_init()) {
>> - pr_err("per-cpu initialization failed\n");
>> - goto pcpufail;
>> +
>> + pool = __zswap_pool_create_fallback();
>> + if (!pool) {
>> + pr_err("pool creation failed\n");
>> + goto pool_fail;
>> }
>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
>> + zpool_get_type(pool->zpool));
>> +
>> + list_add(&pool->list, &zswap_pools);
>>
>> frontswap_register_ops(&zswap_frontswap_ops);
>> if (zswap_debugfs_init())
>> pr_warn("debugfs initialization failed\n");
>> return 0;
>> -pcpufail:
>> - zswap_comp_exit();
>> -compfail:
>> +
>> +pool_fail:
>> + zswap_cpu_dstmem_destroy();
>> +dstmem_fail:
>> zswap_entry_cache_destroy();
>> -cachefail:
>> - zpool_destroy_pool(zswap_pool);
>> -error:
>> +cache_fail:
>> return -ENOMEM;
>> }
>> /* must be late so crypto has time to come up */
>> --
>> 2.1.0
>>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-10 20:54 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-10 20:54 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>> Add dynamic creation of pools. Move the static crypto compression
>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
>> the pool it's in.
>
> Seth, as far as the design, from your previous comments I assume you
> were thinking of maintaining separate lists of zpools and compressors?
> I do see how that will reduce duplication of zpools and compressors,
> but it also requires adding a new pointer to each zswap_entry, and
> increasing the amount of code to manage each list separately. And the
> most common case in zswap will be just a single zpool and compressor,
> not repeatedly changing params. What do you think?
Any opinion on this patch? If you want, I can break it up so there's
a list of zpools and a list of compressors. Either the combined way
(this patch) or separate lists works for me, as long as the params are
changeable at runtime :-)
>
>>
>> This is required by a separate patch which enables changing the
>> zswap zpool and compressor params at runtime.
>>
>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
>> ---
>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
>> 1 file changed, 408 insertions(+), 142 deletions(-)
>>
>> diff --git a/mm/zswap.c b/mm/zswap.c
>> index 2d5727b..fc93770 100644
>> --- a/mm/zswap.c
>> +++ b/mm/zswap.c
>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
>> static struct zpool *zswap_pool;
>>
>> /*********************************
>> -* compression functions
>> +* data structures
>> **********************************/
>> -/* per-cpu compression transforms */
>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>>
>> -enum comp_op {
>> - ZSWAP_COMPOP_COMPRESS,
>> - ZSWAP_COMPOP_DECOMPRESS
>> +struct zswap_pool {
>> + struct zpool *zpool;
>> + struct kref kref;
>> + struct list_head list;
>> + struct rcu_head rcu_head;
>> + struct notifier_block notifier;
>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
>> + struct crypto_comp * __percpu *tfm;
>> };
>>
>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
>> - u8 *dst, unsigned int *dlen)
>> -{
>> - struct crypto_comp *tfm;
>> - int ret;
>> -
>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
>> - switch (op) {
>> - case ZSWAP_COMPOP_COMPRESS:
>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
>> - break;
>> - case ZSWAP_COMPOP_DECOMPRESS:
>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
>> - break;
>> - default:
>> - ret = -EINVAL;
>> - }
>> -
>> - put_cpu();
>> - return ret;
>> -}
>> -
>> -static int __init zswap_comp_init(void)
>> -{
>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>> - pr_info("%s compressor not available\n", zswap_compressor);
>> - /* fall back to default compressor */
>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
>> - /* can't even load the default compressor */
>> - return -ENODEV;
>> - }
>> - pr_info("using %s compressor\n", zswap_compressor);
>> -
>> - /* alloc percpu transforms */
>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
>> - if (!zswap_comp_pcpu_tfms)
>> - return -ENOMEM;
>> - return 0;
>> -}
>> -
>> -static void __init zswap_comp_exit(void)
>> -{
>> - /* free percpu transforms */
>> - free_percpu(zswap_comp_pcpu_tfms);
>> -}
>> -
>> -/*********************************
>> -* data structures
>> -**********************************/
>> /*
>> * struct zswap_entry
>> *
>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
>> * page within zswap.
>> *
>> * rbnode - links the entry into red-black tree for the appropriate swap type
>> + * offset - the swap offset for the entry. Index into the red-black tree.
>> * refcount - the number of outstanding reference to the entry. This is needed
>> * to protect against premature freeing of the entry by code
>> * concurrent calls to load, invalidate, and writeback. The lock
>> * for the zswap_tree structure that contains the entry must
>> * be held while changing the refcount. Since the lock must
>> * be held, there is no reason to also make refcount atomic.
>> - * offset - the swap offset for the entry. Index into the red-black tree.
>> - * handle - zpool allocation handle that stores the compressed page data
>> * length - the length in bytes of the compressed page data. Needed during
>> * decompression
>> + * pool - the zswap_pool the entry's data is in
>> + * handle - zpool allocation handle that stores the compressed page data
>> */
>> struct zswap_entry {
>> struct rb_node rbnode;
>> pgoff_t offset;
>> int refcount;
>> unsigned int length;
>> + struct zswap_pool *pool;
>> unsigned long handle;
>> };
>>
>> @@ -201,6 +156,44 @@ struct zswap_tree {
>>
>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>>
>> +/* RCU-protected iteration */
>> +static LIST_HEAD(zswap_pools);
>> +/* protects zswap_pools list modification */
>> +static DEFINE_SPINLOCK(zswap_pools_lock);
>> +
>> +/*********************************
>> +* helpers and fwd declarations
>> +**********************************/
>> +
>> +#define zswap_pool_debug(msg, p) \
>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
>> + zpool_get_type((p)->zpool))
>> +
>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
>> +static int zswap_pool_get(struct zswap_pool *pool);
>> +static void zswap_pool_put(struct zswap_pool *pool);
>> +
>> +static bool zswap_is_full(void)
>> +{
>> + return totalram_pages * zswap_max_pool_percent / 100 <
>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>> +}
>> +
>> +static void zswap_update_total_size(void)
>> +{
>> + struct zswap_pool *pool;
>> + u64 total = 0;
>> +
>> + rcu_read_lock();
>> +
>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>> + total += zpool_get_total_size(pool->zpool);
>> +
>> + rcu_read_unlock();
>> +
>> + zswap_pool_total_size = total;
>> +}
>> +
>> /*********************************
>> * zswap entry functions
>> **********************************/
>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
>> */
>> static void zswap_free_entry(struct zswap_entry *entry)
>> {
>> - zpool_free(zswap_pool, entry->handle);
>> + zpool_free(entry->pool->zpool, entry->handle);
>> + zswap_pool_put(entry->pool);
>> zswap_entry_cache_free(entry);
>> atomic_dec(&zswap_stored_pages);
>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>> + zswap_update_total_size();
>> }
>>
>> /* caller must hold the tree lock */
>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
>> **********************************/
>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>>
>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
>> {
>> - struct crypto_comp *tfm;
>> u8 *dst;
>>
>> switch (action) {
>> case CPU_UP_PREPARE:
>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
>> - if (IS_ERR(tfm)) {
>> - pr_err("can't allocate compressor transform\n");
>> - return NOTIFY_BAD;
>> - }
>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
>> if (!dst) {
>> pr_err("can't allocate compressor buffer\n");
>> - crypto_free_comp(tfm);
>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>> return NOTIFY_BAD;
>> }
>> per_cpu(zswap_dstmem, cpu) = dst;
>> break;
>> case CPU_DEAD:
>> case CPU_UP_CANCELED:
>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
>> - if (tfm) {
>> - crypto_free_comp(tfm);
>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>> - }
>> dst = per_cpu(zswap_dstmem, cpu);
>> kfree(dst);
>> per_cpu(zswap_dstmem, cpu) = NULL;
>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>> return NOTIFY_OK;
>> }
>>
>> -static int zswap_cpu_notifier(struct notifier_block *nb,
>> - unsigned long action, void *pcpu)
>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
>> + unsigned long action, void *pcpu)
>> {
>> - unsigned long cpu = (unsigned long)pcpu;
>> - return __zswap_cpu_notifier(action, cpu);
>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
>> }
>>
>> -static struct notifier_block zswap_cpu_notifier_block = {
>> - .notifier_call = zswap_cpu_notifier
>> +static struct notifier_block zswap_dstmem_notifier = {
>> + .notifier_call = zswap_cpu_dstmem_notifier,
>> };
>>
>> -static int __init zswap_cpu_init(void)
>> +static int __init zswap_cpu_dstmem_init(void)
>> {
>> unsigned long cpu;
>>
>> cpu_notifier_register_begin();
>> for_each_online_cpu(cpu)
>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
>> + NOTIFY_BAD)
>> goto cleanup;
>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
>> + __register_cpu_notifier(&zswap_dstmem_notifier);
>> cpu_notifier_register_done();
>> return 0;
>>
>> cleanup:
>> for_each_online_cpu(cpu)
>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>> cpu_notifier_register_done();
>> return -ENOMEM;
>> }
>>
>> +static void zswap_cpu_dstmem_destroy(void)
>> +{
>> + unsigned long cpu;
>> +
>> + cpu_notifier_register_begin();
>> + for_each_online_cpu(cpu)
>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
>> + cpu_notifier_register_done();
>> +}
>> +
>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
>> + unsigned long action, unsigned long cpu)
>> +{
>> + struct crypto_comp *tfm;
>> +
>> + switch (action) {
>> + case CPU_UP_PREPARE:
>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
>> + break;
>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
>> + if (IS_ERR_OR_NULL(tfm)) {
>> + pr_err("could not alloc crypto comp %s : %ld\n",
>> + pool->tfm_name, PTR_ERR(tfm));
>> + return NOTIFY_BAD;
>> + }
>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
>> + break;
>> + case CPU_DEAD:
>> + case CPU_UP_CANCELED:
>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
>> + if (!IS_ERR_OR_NULL(tfm))
>> + crypto_free_comp(tfm);
>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
>> + break;
>> + default:
>> + break;
>> + }
>> + return NOTIFY_OK;
>> +}
>> +
>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
>> + unsigned long action, void *pcpu)
>> +{
>> + unsigned long cpu = (unsigned long)pcpu;
>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
>> +
>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
>> +}
>> +
>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
>> +{
>> + unsigned long cpu;
>> +
>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
>> +
>> + cpu_notifier_register_begin();
>> + for_each_online_cpu(cpu)
>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
>> + NOTIFY_BAD)
>> + goto cleanup;
>> + __register_cpu_notifier(&pool->notifier);
>> + cpu_notifier_register_done();
>> + return 0;
>> +
>> +cleanup:
>> + for_each_online_cpu(cpu)
>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>> + cpu_notifier_register_done();
>> + return -ENOMEM;
>> +}
>> +
>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
>> +{
>> + unsigned long cpu;
>> +
>> + cpu_notifier_register_begin();
>> + for_each_online_cpu(cpu)
>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>> + __unregister_cpu_notifier(&pool->notifier);
>> + cpu_notifier_register_done();
>> +}
>> +
>> /*********************************
>> -* helpers
>> +* pool functions
>> **********************************/
>> -static bool zswap_is_full(void)
>> +
>> +static struct zswap_pool *__zswap_pool_current(void)
>> {
>> - return totalram_pages * zswap_max_pool_percent / 100 <
>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>> + struct zswap_pool *pool;
>> +
>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
>> + WARN_ON(!pool);
>> +
>> + return pool;
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_current(void)
>> +{
>> + assert_spin_locked(&zswap_pools_lock);
>> +
>> + return __zswap_pool_current();
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_current_get(void)
>> +{
>> + struct zswap_pool *pool;
>> +
>> + rcu_read_lock();
>> +
>> + pool = __zswap_pool_current();
>> + if (!pool || !zswap_pool_get(pool))
>> + pool = NULL;
>> +
>> + rcu_read_unlock();
>> +
>> + return pool;
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_last_get(void)
>> +{
>> + struct zswap_pool *pool, *last = NULL;
>> +
>> + rcu_read_lock();
>> +
>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>> + last = pool;
>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
>> + last = NULL;
>> +
>> + rcu_read_unlock();
>> +
>> + return last;
>> +}
>> +
>> +static struct zpool_ops zswap_zpool_ops = {
>> + .evict = zswap_writeback_entry
>> +};
>> +
>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
>> +{
>> + struct zswap_pool *pool;
>> +
>> + assert_spin_locked(&zswap_pools_lock);
>> +
>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
>> + continue;
>> + if (strncmp(zpool_get_type(pool->zpool), type,
>> + sizeof(zswap_zpool_type)))
>> + continue;
>> + /* if we can't get it, it's about to be destroyed */
>> + if (!zswap_pool_get(pool))
>> + continue;
>> + return pool;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
>> +{
>> + struct zswap_pool *pool;
>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>> +
>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
>> + if (!pool) {
>> + pr_err("pool alloc failed\n");
>> + return NULL;
>> + }
>> +
>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
>> + if (!pool->zpool) {
>> + pr_err("%s zpool not available\n", type);
>> + goto error;
>> + }
>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
>> +
>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
>> + pool->tfm = alloc_percpu(struct crypto_comp *);
>> + if (!pool->tfm) {
>> + pr_err("percpu alloc failed\n");
>> + goto error;
>> + }
>> +
>> + if (zswap_cpu_comp_init(pool))
>> + goto error;
>> + pr_debug("using %s compressor\n", pool->tfm_name);
>> +
>> + /* being the current pool takes 1 ref; this func expects the
>> + * caller to always add the new pool as the current pool
>> + */
>> + kref_init(&pool->kref);
>> + INIT_LIST_HEAD(&pool->list);
>> +
>> + zswap_pool_debug("created", pool);
>> +
>> + return pool;
>> +
>> +error:
>> + free_percpu(pool->tfm);
>> + if (pool->zpool)
>> + zpool_destroy_pool(pool->zpool);
>> + kfree(pool);
>> + return NULL;
>> +}
>> +
>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
>> +{
>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>> + pr_err("compressor %s not available, using default %s\n",
>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
>> + sizeof(zswap_compressor));
>> + }
>> + if (!zpool_has_pool(zswap_zpool_type)) {
>> + pr_err("zpool %s not available, using default %s\n",
>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
>> + sizeof(zswap_zpool_type));
>> + }
>> +
>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
>> +}
>> +
>> +static void zswap_pool_destroy(struct zswap_pool *pool)
>> +{
>> + zswap_pool_debug("destroying", pool);
>> +
>> + zswap_cpu_comp_destroy(pool);
>> + free_percpu(pool->tfm);
>> + zpool_destroy_pool(pool->zpool);
>> + kfree(pool);
>> +}
>> +
>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
>> +{
>> + return kref_get_unless_zero(&pool->kref);
>> +}
>> +
>> +static void __zswap_pool_release(struct rcu_head *head)
>> +{
>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
>> +
>> + /* nobody should have been able to get a kref... */
>> + WARN_ON(kref_get_unless_zero(&pool->kref));
>> +
>> + /* pool is now off zswap_pools list and has no references. */
>> + zswap_pool_destroy(pool);
>> +}
>> +
>> +static void __zswap_pool_empty(struct kref *kref)
>> +{
>> + struct zswap_pool *pool;
>> +
>> + pool = container_of(kref, typeof(*pool), kref);
>> +
>> + spin_lock(&zswap_pools_lock);
>> +
>> + WARN_ON(pool == zswap_pool_current());
>> +
>> + list_del_rcu(&pool->list);
>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
>> +
>> + spin_unlock(&zswap_pools_lock);
>> +}
>> +
>> +static void zswap_pool_put(struct zswap_pool *pool)
>> +{
>> + kref_put(&pool->kref, __zswap_pool_empty);
>> +}
>> +
>> }
>>
>> /*********************************
>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>> pgoff_t offset;
>> struct zswap_entry *entry;
>> struct page *page;
>> + struct crypto_comp *tfm;
>> u8 *src, *dst;
>> unsigned int dlen;
>> int ret;
>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
>> /* decompress */
>> dlen = PAGE_SIZE;
>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>> dst = kmap_atomic(page);
>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
>> - entry->length, dst, &dlen);
>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>> + ret = crypto_comp_decompress(tfm, src, entry->length,
>> + dst, &dlen);
>> + put_cpu_ptr(entry->pool->tfm);
>> kunmap_atomic(dst);
>> - zpool_unmap_handle(zswap_pool, entry->handle);
>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>> BUG_ON(ret);
>> BUG_ON(dlen != PAGE_SIZE);
>>
>> @@ -633,6 +882,22 @@ end:
>> return ret;
>> }
>>
>> +static int zswap_shrink(void)
>> +{
>> + struct zswap_pool *pool;
>> + int ret;
>> +
>> + pool = zswap_pool_last_get();
>> + if (!pool)
>> + return -ENOENT;
>> +
>> + ret = zpool_shrink(pool->zpool, 1, NULL);
>> +
>> + zswap_pool_put(pool);
>> +
>> + return ret;
>> +}
>> +
>> /*********************************
>> * frontswap hooks
>> **********************************/
>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>> {
>> struct zswap_tree *tree = zswap_trees[type];
>> struct zswap_entry *entry, *dupentry;
>> + struct crypto_comp *tfm;
>> int ret;
>> unsigned int dlen = PAGE_SIZE, len;
>> unsigned long handle;
>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>> /* reclaim space if needed */
>> if (zswap_is_full()) {
>> zswap_pool_limit_hit++;
>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
>> + if (zswap_shrink()) {
>> zswap_reject_reclaim_fail++;
>> ret = -ENOMEM;
>> goto reject;
>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>> goto reject;
>> }
>>
>> + /* if entry is successfully added, it keeps the reference */
>> + entry->pool = zswap_pool_current_get();
>> + if (!entry->pool) {
>> + ret = -EINVAL;
>> + goto freepage;
>> + }
>> +
>> /* compress */
>> dst = get_cpu_var(zswap_dstmem);
>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>> src = kmap_atomic(page);
>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
>> kunmap_atomic(src);
>> + put_cpu_ptr(entry->pool->tfm);
>> if (ret) {
>> ret = -EINVAL;
>> - goto freepage;
>> + goto put_dstmem;
>> }
>>
>> /* store */
>> len = dlen + sizeof(struct zswap_header);
>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
>> - &handle);
>> + ret = zpool_malloc(entry->pool->zpool, len,
>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
>> if (ret == -ENOSPC) {
>> zswap_reject_compress_poor++;
>> - goto freepage;
>> + goto put_dstmem;
>> }
>> if (ret) {
>> zswap_reject_alloc_fail++;
>> - goto freepage;
>> + goto put_dstmem;
>> }
>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
>> zhdr->swpentry = swp_entry(type, offset);
>> buf = (u8 *)(zhdr + 1);
>> memcpy(buf, dst, dlen);
>> - zpool_unmap_handle(zswap_pool, handle);
>> + zpool_unmap_handle(entry->pool->zpool, handle);
>> put_cpu_var(zswap_dstmem);
>>
>> /* populate entry */
>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>
>> /* update stats */
>> atomic_inc(&zswap_stored_pages);
>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>> + zswap_update_total_size();
>>
>> return 0;
>>
>> -freepage:
>> +put_dstmem:
>> put_cpu_var(zswap_dstmem);
>> + zswap_pool_put(entry->pool);
>> +freepage:
>> zswap_entry_cache_free(entry);
>> reject:
>> return ret;
>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>> {
>> struct zswap_tree *tree = zswap_trees[type];
>> struct zswap_entry *entry;
>> + struct crypto_comp *tfm;
>> u8 *src, *dst;
>> unsigned int dlen;
>> int ret;
>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>
>> /* decompress */
>> dlen = PAGE_SIZE;
>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>> dst = kmap_atomic(page);
>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
>> - dst, &dlen);
>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
>> + put_cpu_ptr(entry->pool->tfm);
>> kunmap_atomic(dst);
>> - zpool_unmap_handle(zswap_pool, entry->handle);
>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>> BUG_ON(ret);
>>
>> spin_lock(&tree->lock);
>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
>> zswap_trees[type] = NULL;
>> }
>>
>> -static struct zpool_ops zswap_zpool_ops = {
>> - .evict = zswap_writeback_entry
>> -};
>> -
>> static void zswap_frontswap_init(unsigned type)
>> {
>> struct zswap_tree *tree;
>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
>> **********************************/
>> static int __init init_zswap(void)
>> {
>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>> + struct zswap_pool *pool;
>>
>> - pr_info("loading zswap\n");
>> -
>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>> - &zswap_zpool_ops);
>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
>> - pr_info("%s zpool not available\n", zswap_zpool_type);
>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>> - &zswap_zpool_ops);
>> - }
>> - if (!zswap_pool) {
>> - pr_err("%s zpool not available\n", zswap_zpool_type);
>> - pr_err("zpool creation failed\n");
>> - goto error;
>> - }
>> - pr_info("using %s pool\n", zswap_zpool_type);
>> + pr_info("loading\n");
>>
>> if (zswap_entry_cache_create()) {
>> pr_err("entry cache creation failed\n");
>> - goto cachefail;
>> + goto cache_fail;
>> }
>> - if (zswap_comp_init()) {
>> - pr_err("compressor initialization failed\n");
>> - goto compfail;
>> +
>> + if (zswap_cpu_dstmem_init()) {
>> + pr_err("dstmem alloc failed\n");
>> + goto dstmem_fail;
>> }
>> - if (zswap_cpu_init()) {
>> - pr_err("per-cpu initialization failed\n");
>> - goto pcpufail;
>> +
>> + pool = __zswap_pool_create_fallback();
>> + if (!pool) {
>> + pr_err("pool creation failed\n");
>> + goto pool_fail;
>> }
>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
>> + zpool_get_type(pool->zpool));
>> +
>> + list_add(&pool->list, &zswap_pools);
>>
>> frontswap_register_ops(&zswap_frontswap_ops);
>> if (zswap_debugfs_init())
>> pr_warn("debugfs initialization failed\n");
>> return 0;
>> -pcpufail:
>> - zswap_comp_exit();
>> -compfail:
>> +
>> +pool_fail:
>> + zswap_cpu_dstmem_destroy();
>> +dstmem_fail:
>> zswap_entry_cache_destroy();
>> -cachefail:
>> - zpool_destroy_pool(zswap_pool);
>> -error:
>> +cache_fail:
>> return -ENOMEM;
>> }
>> /* must be late so crypto has time to come up */
>> --
>> 2.1.0
>>
--
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-10 20:54 ` Dan Streetman
@ 2015-06-11 18:51 ` Seth Jennings
-1 siblings, 0 replies; 22+ messages in thread
From: Seth Jennings @ 2015-06-11 18:51 UTC (permalink / raw)
To: Dan Streetman; +Cc: Andrew Morton, Linux-MM, linux-kernel
On Wed, Jun 10, 2015 at 04:54:24PM -0400, Dan Streetman wrote:
> On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> > On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> >> Add dynamic creation of pools. Move the static crypto compression
> >> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> >> the pool it's in.
> >
> > Seth, as far as the design, from your previous comments I assume you
> > were thinking of maintaining separate lists of zpools and compressors?
> > I do see how that will reduce duplication of zpools and compressors,
> > but it also requires adding a new pointer to each zswap_entry, and
> > increasing the amount of code to manage each list separately. And the
> > most common case in zswap will be just a single zpool and compressor,
> > not repeatedly changing params. What do you think?
>
> Any opinion on this patch? If you want, I can break it up so there's
> a list of zpools and a list of compressors. Either the combined way
> (this patch) or separate lists works for me, as long as the params are
> changeable at runtime :-)
I'm still reviewing the code. I was going to test it too but it doesn't
compile for me:
CC mm/zswap.o
mm/zswap.c: In function ‘__zswap_pool_create_fallback’:
mm/zswap.c:605:10: warning: argument to ‘sizeof’ in ‘strncpy’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
sizeof(zswap_compressor));
^
mm/zswap.c:607:7: error: implicit declaration of function ‘zpool_has_pool’ [-Werror=implicit-function-declaration]
if (!zpool_has_pool(zswap_zpool_type)) {
^
mm/zswap.c:611:10: warning: argument to ‘sizeof’ in ‘strncpy’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
sizeof(zswap_zpool_type));
^
mm/zswap.c: At top level:
mm/zswap.c:664:1: error: expected identifier or ‘(’ before ‘}’ token
}
^
mm/zswap.c:99:22: warning: ‘zswap_pool’ defined but not used [-Wunused-variable]
static struct zpool *zswap_pool;
^
mm/zswap.c:531:27: warning: ‘zswap_pool_find_get’ defined but not used [-Wunused-function]
static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
^
Seth
>
>
> >
> >>
> >> This is required by a separate patch which enables changing the
> >> zswap zpool and compressor params at runtime.
> >>
> >> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> >> ---
> >> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> >> 1 file changed, 408 insertions(+), 142 deletions(-)
> >>
> >> diff --git a/mm/zswap.c b/mm/zswap.c
> >> index 2d5727b..fc93770 100644
> >> --- a/mm/zswap.c
> >> +++ b/mm/zswap.c
> >> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> >> static struct zpool *zswap_pool;
> >>
> >> /*********************************
> >> -* compression functions
> >> +* data structures
> >> **********************************/
> >> -/* per-cpu compression transforms */
> >> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> >>
> >> -enum comp_op {
> >> - ZSWAP_COMPOP_COMPRESS,
> >> - ZSWAP_COMPOP_DECOMPRESS
> >> +struct zswap_pool {
> >> + struct zpool *zpool;
> >> + struct kref kref;
> >> + struct list_head list;
> >> + struct rcu_head rcu_head;
> >> + struct notifier_block notifier;
> >> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> >> + struct crypto_comp * __percpu *tfm;
> >> };
> >>
> >> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> >> - u8 *dst, unsigned int *dlen)
> >> -{
> >> - struct crypto_comp *tfm;
> >> - int ret;
> >> -
> >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> >> - switch (op) {
> >> - case ZSWAP_COMPOP_COMPRESS:
> >> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> >> - break;
> >> - case ZSWAP_COMPOP_DECOMPRESS:
> >> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> >> - break;
> >> - default:
> >> - ret = -EINVAL;
> >> - }
> >> -
> >> - put_cpu();
> >> - return ret;
> >> -}
> >> -
> >> -static int __init zswap_comp_init(void)
> >> -{
> >> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >> - pr_info("%s compressor not available\n", zswap_compressor);
> >> - /* fall back to default compressor */
> >> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> >> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> >> - /* can't even load the default compressor */
> >> - return -ENODEV;
> >> - }
> >> - pr_info("using %s compressor\n", zswap_compressor);
> >> -
> >> - /* alloc percpu transforms */
> >> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> >> - if (!zswap_comp_pcpu_tfms)
> >> - return -ENOMEM;
> >> - return 0;
> >> -}
> >> -
> >> -static void __init zswap_comp_exit(void)
> >> -{
> >> - /* free percpu transforms */
> >> - free_percpu(zswap_comp_pcpu_tfms);
> >> -}
> >> -
> >> -/*********************************
> >> -* data structures
> >> -**********************************/
> >> /*
> >> * struct zswap_entry
> >> *
> >> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> >> * page within zswap.
> >> *
> >> * rbnode - links the entry into red-black tree for the appropriate swap type
> >> + * offset - the swap offset for the entry. Index into the red-black tree.
> >> * refcount - the number of outstanding reference to the entry. This is needed
> >> * to protect against premature freeing of the entry by code
> >> * concurrent calls to load, invalidate, and writeback. The lock
> >> * for the zswap_tree structure that contains the entry must
> >> * be held while changing the refcount. Since the lock must
> >> * be held, there is no reason to also make refcount atomic.
> >> - * offset - the swap offset for the entry. Index into the red-black tree.
> >> - * handle - zpool allocation handle that stores the compressed page data
> >> * length - the length in bytes of the compressed page data. Needed during
> >> * decompression
> >> + * pool - the zswap_pool the entry's data is in
> >> + * handle - zpool allocation handle that stores the compressed page data
> >> */
> >> struct zswap_entry {
> >> struct rb_node rbnode;
> >> pgoff_t offset;
> >> int refcount;
> >> unsigned int length;
> >> + struct zswap_pool *pool;
> >> unsigned long handle;
> >> };
> >>
> >> @@ -201,6 +156,44 @@ struct zswap_tree {
> >>
> >> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> >>
> >> +/* RCU-protected iteration */
> >> +static LIST_HEAD(zswap_pools);
> >> +/* protects zswap_pools list modification */
> >> +static DEFINE_SPINLOCK(zswap_pools_lock);
> >> +
> >> +/*********************************
> >> +* helpers and fwd declarations
> >> +**********************************/
> >> +
> >> +#define zswap_pool_debug(msg, p) \
> >> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> >> + zpool_get_type((p)->zpool))
> >> +
> >> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> >> +static int zswap_pool_get(struct zswap_pool *pool);
> >> +static void zswap_pool_put(struct zswap_pool *pool);
> >> +
> >> +static bool zswap_is_full(void)
> >> +{
> >> + return totalram_pages * zswap_max_pool_percent / 100 <
> >> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >> +}
> >> +
> >> +static void zswap_update_total_size(void)
> >> +{
> >> + struct zswap_pool *pool;
> >> + u64 total = 0;
> >> +
> >> + rcu_read_lock();
> >> +
> >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >> + total += zpool_get_total_size(pool->zpool);
> >> +
> >> + rcu_read_unlock();
> >> +
> >> + zswap_pool_total_size = total;
> >> +}
> >> +
> >> /*********************************
> >> * zswap entry functions
> >> **********************************/
> >> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> >> */
> >> static void zswap_free_entry(struct zswap_entry *entry)
> >> {
> >> - zpool_free(zswap_pool, entry->handle);
> >> + zpool_free(entry->pool->zpool, entry->handle);
> >> + zswap_pool_put(entry->pool);
> >> zswap_entry_cache_free(entry);
> >> atomic_dec(&zswap_stored_pages);
> >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >> + zswap_update_total_size();
> >> }
> >>
> >> /* caller must hold the tree lock */
> >> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> >> **********************************/
> >> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> >>
> >> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> >> {
> >> - struct crypto_comp *tfm;
> >> u8 *dst;
> >>
> >> switch (action) {
> >> case CPU_UP_PREPARE:
> >> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> >> - if (IS_ERR(tfm)) {
> >> - pr_err("can't allocate compressor transform\n");
> >> - return NOTIFY_BAD;
> >> - }
> >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> >> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> >> if (!dst) {
> >> pr_err("can't allocate compressor buffer\n");
> >> - crypto_free_comp(tfm);
> >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >> return NOTIFY_BAD;
> >> }
> >> per_cpu(zswap_dstmem, cpu) = dst;
> >> break;
> >> case CPU_DEAD:
> >> case CPU_UP_CANCELED:
> >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> >> - if (tfm) {
> >> - crypto_free_comp(tfm);
> >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >> - }
> >> dst = per_cpu(zswap_dstmem, cpu);
> >> kfree(dst);
> >> per_cpu(zswap_dstmem, cpu) = NULL;
> >> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >> return NOTIFY_OK;
> >> }
> >>
> >> -static int zswap_cpu_notifier(struct notifier_block *nb,
> >> - unsigned long action, void *pcpu)
> >> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> >> + unsigned long action, void *pcpu)
> >> {
> >> - unsigned long cpu = (unsigned long)pcpu;
> >> - return __zswap_cpu_notifier(action, cpu);
> >> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> >> }
> >>
> >> -static struct notifier_block zswap_cpu_notifier_block = {
> >> - .notifier_call = zswap_cpu_notifier
> >> +static struct notifier_block zswap_dstmem_notifier = {
> >> + .notifier_call = zswap_cpu_dstmem_notifier,
> >> };
> >>
> >> -static int __init zswap_cpu_init(void)
> >> +static int __init zswap_cpu_dstmem_init(void)
> >> {
> >> unsigned long cpu;
> >>
> >> cpu_notifier_register_begin();
> >> for_each_online_cpu(cpu)
> >> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> >> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> >> + NOTIFY_BAD)
> >> goto cleanup;
> >> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> >> + __register_cpu_notifier(&zswap_dstmem_notifier);
> >> cpu_notifier_register_done();
> >> return 0;
> >>
> >> cleanup:
> >> for_each_online_cpu(cpu)
> >> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >> cpu_notifier_register_done();
> >> return -ENOMEM;
> >> }
> >>
> >> +static void zswap_cpu_dstmem_destroy(void)
> >> +{
> >> + unsigned long cpu;
> >> +
> >> + cpu_notifier_register_begin();
> >> + for_each_online_cpu(cpu)
> >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> >> + cpu_notifier_register_done();
> >> +}
> >> +
> >> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> >> + unsigned long action, unsigned long cpu)
> >> +{
> >> + struct crypto_comp *tfm;
> >> +
> >> + switch (action) {
> >> + case CPU_UP_PREPARE:
> >> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> >> + break;
> >> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> >> + if (IS_ERR_OR_NULL(tfm)) {
> >> + pr_err("could not alloc crypto comp %s : %ld\n",
> >> + pool->tfm_name, PTR_ERR(tfm));
> >> + return NOTIFY_BAD;
> >> + }
> >> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> >> + break;
> >> + case CPU_DEAD:
> >> + case CPU_UP_CANCELED:
> >> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> >> + if (!IS_ERR_OR_NULL(tfm))
> >> + crypto_free_comp(tfm);
> >> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> >> + break;
> >> + default:
> >> + break;
> >> + }
> >> + return NOTIFY_OK;
> >> +}
> >> +
> >> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> >> + unsigned long action, void *pcpu)
> >> +{
> >> + unsigned long cpu = (unsigned long)pcpu;
> >> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> >> +
> >> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> >> +}
> >> +
> >> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> >> +{
> >> + unsigned long cpu;
> >> +
> >> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> >> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> >> +
> >> + cpu_notifier_register_begin();
> >> + for_each_online_cpu(cpu)
> >> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> >> + NOTIFY_BAD)
> >> + goto cleanup;
> >> + __register_cpu_notifier(&pool->notifier);
> >> + cpu_notifier_register_done();
> >> + return 0;
> >> +
> >> +cleanup:
> >> + for_each_online_cpu(cpu)
> >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >> + cpu_notifier_register_done();
> >> + return -ENOMEM;
> >> +}
> >> +
> >> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> >> +{
> >> + unsigned long cpu;
> >> +
> >> + cpu_notifier_register_begin();
> >> + for_each_online_cpu(cpu)
> >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >> + __unregister_cpu_notifier(&pool->notifier);
> >> + cpu_notifier_register_done();
> >> +}
> >> +
> >> /*********************************
> >> -* helpers
> >> +* pool functions
> >> **********************************/
> >> -static bool zswap_is_full(void)
> >> +
> >> +static struct zswap_pool *__zswap_pool_current(void)
> >> {
> >> - return totalram_pages * zswap_max_pool_percent / 100 <
> >> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >> + struct zswap_pool *pool;
> >> +
> >> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> >> + WARN_ON(!pool);
> >> +
> >> + return pool;
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_current(void)
> >> +{
> >> + assert_spin_locked(&zswap_pools_lock);
> >> +
> >> + return __zswap_pool_current();
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_current_get(void)
> >> +{
> >> + struct zswap_pool *pool;
> >> +
> >> + rcu_read_lock();
> >> +
> >> + pool = __zswap_pool_current();
> >> + if (!pool || !zswap_pool_get(pool))
> >> + pool = NULL;
> >> +
> >> + rcu_read_unlock();
> >> +
> >> + return pool;
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_last_get(void)
> >> +{
> >> + struct zswap_pool *pool, *last = NULL;
> >> +
> >> + rcu_read_lock();
> >> +
> >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >> + last = pool;
> >> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> >> + last = NULL;
> >> +
> >> + rcu_read_unlock();
> >> +
> >> + return last;
> >> +}
> >> +
> >> +static struct zpool_ops zswap_zpool_ops = {
> >> + .evict = zswap_writeback_entry
> >> +};
> >> +
> >> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> >> +{
> >> + struct zswap_pool *pool;
> >> +
> >> + assert_spin_locked(&zswap_pools_lock);
> >> +
> >> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> >> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> >> + continue;
> >> + if (strncmp(zpool_get_type(pool->zpool), type,
> >> + sizeof(zswap_zpool_type)))
> >> + continue;
> >> + /* if we can't get it, it's about to be destroyed */
> >> + if (!zswap_pool_get(pool))
> >> + continue;
> >> + return pool;
> >> + }
> >> +
> >> + return NULL;
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> >> +{
> >> + struct zswap_pool *pool;
> >> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >> +
> >> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> >> + if (!pool) {
> >> + pr_err("pool alloc failed\n");
> >> + return NULL;
> >> + }
> >> +
> >> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> >> + if (!pool->zpool) {
> >> + pr_err("%s zpool not available\n", type);
> >> + goto error;
> >> + }
> >> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> >> +
> >> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> >> + pool->tfm = alloc_percpu(struct crypto_comp *);
> >> + if (!pool->tfm) {
> >> + pr_err("percpu alloc failed\n");
> >> + goto error;
> >> + }
> >> +
> >> + if (zswap_cpu_comp_init(pool))
> >> + goto error;
> >> + pr_debug("using %s compressor\n", pool->tfm_name);
> >> +
> >> + /* being the current pool takes 1 ref; this func expects the
> >> + * caller to always add the new pool as the current pool
> >> + */
> >> + kref_init(&pool->kref);
> >> + INIT_LIST_HEAD(&pool->list);
> >> +
> >> + zswap_pool_debug("created", pool);
> >> +
> >> + return pool;
> >> +
> >> +error:
> >> + free_percpu(pool->tfm);
> >> + if (pool->zpool)
> >> + zpool_destroy_pool(pool->zpool);
> >> + kfree(pool);
> >> + return NULL;
> >> +}
> >> +
> >> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> >> +{
> >> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >> + pr_err("compressor %s not available, using default %s\n",
> >> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> >> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> >> + sizeof(zswap_compressor));
> >> + }
> >> + if (!zpool_has_pool(zswap_zpool_type)) {
> >> + pr_err("zpool %s not available, using default %s\n",
> >> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> >> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> >> + sizeof(zswap_zpool_type));
> >> + }
> >> +
> >> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> >> +}
> >> +
> >> +static void zswap_pool_destroy(struct zswap_pool *pool)
> >> +{
> >> + zswap_pool_debug("destroying", pool);
> >> +
> >> + zswap_cpu_comp_destroy(pool);
> >> + free_percpu(pool->tfm);
> >> + zpool_destroy_pool(pool->zpool);
> >> + kfree(pool);
> >> +}
> >> +
> >> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> >> +{
> >> + return kref_get_unless_zero(&pool->kref);
> >> +}
> >> +
> >> +static void __zswap_pool_release(struct rcu_head *head)
> >> +{
> >> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> >> +
> >> + /* nobody should have been able to get a kref... */
> >> + WARN_ON(kref_get_unless_zero(&pool->kref));
> >> +
> >> + /* pool is now off zswap_pools list and has no references. */
> >> + zswap_pool_destroy(pool);
> >> +}
> >> +
> >> +static void __zswap_pool_empty(struct kref *kref)
> >> +{
> >> + struct zswap_pool *pool;
> >> +
> >> + pool = container_of(kref, typeof(*pool), kref);
> >> +
> >> + spin_lock(&zswap_pools_lock);
> >> +
> >> + WARN_ON(pool == zswap_pool_current());
> >> +
> >> + list_del_rcu(&pool->list);
> >> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> >> +
> >> + spin_unlock(&zswap_pools_lock);
> >> +}
> >> +
> >> +static void zswap_pool_put(struct zswap_pool *pool)
> >> +{
> >> + kref_put(&pool->kref, __zswap_pool_empty);
> >> +}
> >> +
> >> }
> >>
> >> /*********************************
> >> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >> pgoff_t offset;
> >> struct zswap_entry *entry;
> >> struct page *page;
> >> + struct crypto_comp *tfm;
> >> u8 *src, *dst;
> >> unsigned int dlen;
> >> int ret;
> >> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> >> /* decompress */
> >> dlen = PAGE_SIZE;
> >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >> dst = kmap_atomic(page);
> >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> >> - entry->length, dst, &dlen);
> >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >> + ret = crypto_comp_decompress(tfm, src, entry->length,
> >> + dst, &dlen);
> >> + put_cpu_ptr(entry->pool->tfm);
> >> kunmap_atomic(dst);
> >> - zpool_unmap_handle(zswap_pool, entry->handle);
> >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >> BUG_ON(ret);
> >> BUG_ON(dlen != PAGE_SIZE);
> >>
> >> @@ -633,6 +882,22 @@ end:
> >> return ret;
> >> }
> >>
> >> +static int zswap_shrink(void)
> >> +{
> >> + struct zswap_pool *pool;
> >> + int ret;
> >> +
> >> + pool = zswap_pool_last_get();
> >> + if (!pool)
> >> + return -ENOENT;
> >> +
> >> + ret = zpool_shrink(pool->zpool, 1, NULL);
> >> +
> >> + zswap_pool_put(pool);
> >> +
> >> + return ret;
> >> +}
> >> +
> >> /*********************************
> >> * frontswap hooks
> >> **********************************/
> >> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >> {
> >> struct zswap_tree *tree = zswap_trees[type];
> >> struct zswap_entry *entry, *dupentry;
> >> + struct crypto_comp *tfm;
> >> int ret;
> >> unsigned int dlen = PAGE_SIZE, len;
> >> unsigned long handle;
> >> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >> /* reclaim space if needed */
> >> if (zswap_is_full()) {
> >> zswap_pool_limit_hit++;
> >> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> >> + if (zswap_shrink()) {
> >> zswap_reject_reclaim_fail++;
> >> ret = -ENOMEM;
> >> goto reject;
> >> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >> goto reject;
> >> }
> >>
> >> + /* if entry is successfully added, it keeps the reference */
> >> + entry->pool = zswap_pool_current_get();
> >> + if (!entry->pool) {
> >> + ret = -EINVAL;
> >> + goto freepage;
> >> + }
> >> +
> >> /* compress */
> >> dst = get_cpu_var(zswap_dstmem);
> >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >> src = kmap_atomic(page);
> >> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> >> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> >> kunmap_atomic(src);
> >> + put_cpu_ptr(entry->pool->tfm);
> >> if (ret) {
> >> ret = -EINVAL;
> >> - goto freepage;
> >> + goto put_dstmem;
> >> }
> >>
> >> /* store */
> >> len = dlen + sizeof(struct zswap_header);
> >> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> >> - &handle);
> >> + ret = zpool_malloc(entry->pool->zpool, len,
> >> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> >> if (ret == -ENOSPC) {
> >> zswap_reject_compress_poor++;
> >> - goto freepage;
> >> + goto put_dstmem;
> >> }
> >> if (ret) {
> >> zswap_reject_alloc_fail++;
> >> - goto freepage;
> >> + goto put_dstmem;
> >> }
> >> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> >> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> >> zhdr->swpentry = swp_entry(type, offset);
> >> buf = (u8 *)(zhdr + 1);
> >> memcpy(buf, dst, dlen);
> >> - zpool_unmap_handle(zswap_pool, handle);
> >> + zpool_unmap_handle(entry->pool->zpool, handle);
> >> put_cpu_var(zswap_dstmem);
> >>
> >> /* populate entry */
> >> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>
> >> /* update stats */
> >> atomic_inc(&zswap_stored_pages);
> >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >> + zswap_update_total_size();
> >>
> >> return 0;
> >>
> >> -freepage:
> >> +put_dstmem:
> >> put_cpu_var(zswap_dstmem);
> >> + zswap_pool_put(entry->pool);
> >> +freepage:
> >> zswap_entry_cache_free(entry);
> >> reject:
> >> return ret;
> >> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >> {
> >> struct zswap_tree *tree = zswap_trees[type];
> >> struct zswap_entry *entry;
> >> + struct crypto_comp *tfm;
> >> u8 *src, *dst;
> >> unsigned int dlen;
> >> int ret;
> >> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>
> >> /* decompress */
> >> dlen = PAGE_SIZE;
> >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >> dst = kmap_atomic(page);
> >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> >> - dst, &dlen);
> >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> >> + put_cpu_ptr(entry->pool->tfm);
> >> kunmap_atomic(dst);
> >> - zpool_unmap_handle(zswap_pool, entry->handle);
> >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >> BUG_ON(ret);
> >>
> >> spin_lock(&tree->lock);
> >> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> >> zswap_trees[type] = NULL;
> >> }
> >>
> >> -static struct zpool_ops zswap_zpool_ops = {
> >> - .evict = zswap_writeback_entry
> >> -};
> >> -
> >> static void zswap_frontswap_init(unsigned type)
> >> {
> >> struct zswap_tree *tree;
> >> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> >> **********************************/
> >> static int __init init_zswap(void)
> >> {
> >> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >> + struct zswap_pool *pool;
> >>
> >> - pr_info("loading zswap\n");
> >> -
> >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >> - &zswap_zpool_ops);
> >> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> >> - pr_info("%s zpool not available\n", zswap_zpool_type);
> >> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >> - &zswap_zpool_ops);
> >> - }
> >> - if (!zswap_pool) {
> >> - pr_err("%s zpool not available\n", zswap_zpool_type);
> >> - pr_err("zpool creation failed\n");
> >> - goto error;
> >> - }
> >> - pr_info("using %s pool\n", zswap_zpool_type);
> >> + pr_info("loading\n");
> >>
> >> if (zswap_entry_cache_create()) {
> >> pr_err("entry cache creation failed\n");
> >> - goto cachefail;
> >> + goto cache_fail;
> >> }
> >> - if (zswap_comp_init()) {
> >> - pr_err("compressor initialization failed\n");
> >> - goto compfail;
> >> +
> >> + if (zswap_cpu_dstmem_init()) {
> >> + pr_err("dstmem alloc failed\n");
> >> + goto dstmem_fail;
> >> }
> >> - if (zswap_cpu_init()) {
> >> - pr_err("per-cpu initialization failed\n");
> >> - goto pcpufail;
> >> +
> >> + pool = __zswap_pool_create_fallback();
> >> + if (!pool) {
> >> + pr_err("pool creation failed\n");
> >> + goto pool_fail;
> >> }
> >> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> >> + zpool_get_type(pool->zpool));
> >> +
> >> + list_add(&pool->list, &zswap_pools);
> >>
> >> frontswap_register_ops(&zswap_frontswap_ops);
> >> if (zswap_debugfs_init())
> >> pr_warn("debugfs initialization failed\n");
> >> return 0;
> >> -pcpufail:
> >> - zswap_comp_exit();
> >> -compfail:
> >> +
> >> +pool_fail:
> >> + zswap_cpu_dstmem_destroy();
> >> +dstmem_fail:
> >> zswap_entry_cache_destroy();
> >> -cachefail:
> >> - zpool_destroy_pool(zswap_pool);
> >> -error:
> >> +cache_fail:
> >> return -ENOMEM;
> >> }
> >> /* must be late so crypto has time to come up */
> >> --
> >> 2.1.0
> >>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-11 18:51 ` Seth Jennings
0 siblings, 0 replies; 22+ messages in thread
From: Seth Jennings @ 2015-06-11 18:51 UTC (permalink / raw)
To: Dan Streetman; +Cc: Andrew Morton, Linux-MM, linux-kernel
On Wed, Jun 10, 2015 at 04:54:24PM -0400, Dan Streetman wrote:
> On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> > On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> >> Add dynamic creation of pools. Move the static crypto compression
> >> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> >> the pool it's in.
> >
> > Seth, as far as the design, from your previous comments I assume you
> > were thinking of maintaining separate lists of zpools and compressors?
> > I do see how that will reduce duplication of zpools and compressors,
> > but it also requires adding a new pointer to each zswap_entry, and
> > increasing the amount of code to manage each list separately. And the
> > most common case in zswap will be just a single zpool and compressor,
> > not repeatedly changing params. What do you think?
>
> Any opinion on this patch? If you want, I can break it up so there's
> a list of zpools and a list of compressors. Either the combined way
> (this patch) or separate lists works for me, as long as the params are
> changeable at runtime :-)
I'm still reviewing the code. I was going to test it too but it doesn't
compile for me:
CC mm/zswap.o
mm/zswap.c: In function a??__zswap_pool_create_fallbacka??:
mm/zswap.c:605:10: warning: argument to a??sizeofa?? in a??strncpya?? call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
sizeof(zswap_compressor));
^
mm/zswap.c:607:7: error: implicit declaration of function a??zpool_has_poola?? [-Werror=implicit-function-declaration]
if (!zpool_has_pool(zswap_zpool_type)) {
^
mm/zswap.c:611:10: warning: argument to a??sizeofa?? in a??strncpya?? call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
sizeof(zswap_zpool_type));
^
mm/zswap.c: At top level:
mm/zswap.c:664:1: error: expected identifier or a??(a?? before a??}a?? token
}
^
mm/zswap.c:99:22: warning: a??zswap_poola?? defined but not used [-Wunused-variable]
static struct zpool *zswap_pool;
^
mm/zswap.c:531:27: warning: a??zswap_pool_find_geta?? defined but not used [-Wunused-function]
static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
^
Seth
>
>
> >
> >>
> >> This is required by a separate patch which enables changing the
> >> zswap zpool and compressor params at runtime.
> >>
> >> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> >> ---
> >> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> >> 1 file changed, 408 insertions(+), 142 deletions(-)
> >>
> >> diff --git a/mm/zswap.c b/mm/zswap.c
> >> index 2d5727b..fc93770 100644
> >> --- a/mm/zswap.c
> >> +++ b/mm/zswap.c
> >> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> >> static struct zpool *zswap_pool;
> >>
> >> /*********************************
> >> -* compression functions
> >> +* data structures
> >> **********************************/
> >> -/* per-cpu compression transforms */
> >> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> >>
> >> -enum comp_op {
> >> - ZSWAP_COMPOP_COMPRESS,
> >> - ZSWAP_COMPOP_DECOMPRESS
> >> +struct zswap_pool {
> >> + struct zpool *zpool;
> >> + struct kref kref;
> >> + struct list_head list;
> >> + struct rcu_head rcu_head;
> >> + struct notifier_block notifier;
> >> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> >> + struct crypto_comp * __percpu *tfm;
> >> };
> >>
> >> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> >> - u8 *dst, unsigned int *dlen)
> >> -{
> >> - struct crypto_comp *tfm;
> >> - int ret;
> >> -
> >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> >> - switch (op) {
> >> - case ZSWAP_COMPOP_COMPRESS:
> >> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> >> - break;
> >> - case ZSWAP_COMPOP_DECOMPRESS:
> >> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> >> - break;
> >> - default:
> >> - ret = -EINVAL;
> >> - }
> >> -
> >> - put_cpu();
> >> - return ret;
> >> -}
> >> -
> >> -static int __init zswap_comp_init(void)
> >> -{
> >> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >> - pr_info("%s compressor not available\n", zswap_compressor);
> >> - /* fall back to default compressor */
> >> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> >> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> >> - /* can't even load the default compressor */
> >> - return -ENODEV;
> >> - }
> >> - pr_info("using %s compressor\n", zswap_compressor);
> >> -
> >> - /* alloc percpu transforms */
> >> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> >> - if (!zswap_comp_pcpu_tfms)
> >> - return -ENOMEM;
> >> - return 0;
> >> -}
> >> -
> >> -static void __init zswap_comp_exit(void)
> >> -{
> >> - /* free percpu transforms */
> >> - free_percpu(zswap_comp_pcpu_tfms);
> >> -}
> >> -
> >> -/*********************************
> >> -* data structures
> >> -**********************************/
> >> /*
> >> * struct zswap_entry
> >> *
> >> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> >> * page within zswap.
> >> *
> >> * rbnode - links the entry into red-black tree for the appropriate swap type
> >> + * offset - the swap offset for the entry. Index into the red-black tree.
> >> * refcount - the number of outstanding reference to the entry. This is needed
> >> * to protect against premature freeing of the entry by code
> >> * concurrent calls to load, invalidate, and writeback. The lock
> >> * for the zswap_tree structure that contains the entry must
> >> * be held while changing the refcount. Since the lock must
> >> * be held, there is no reason to also make refcount atomic.
> >> - * offset - the swap offset for the entry. Index into the red-black tree.
> >> - * handle - zpool allocation handle that stores the compressed page data
> >> * length - the length in bytes of the compressed page data. Needed during
> >> * decompression
> >> + * pool - the zswap_pool the entry's data is in
> >> + * handle - zpool allocation handle that stores the compressed page data
> >> */
> >> struct zswap_entry {
> >> struct rb_node rbnode;
> >> pgoff_t offset;
> >> int refcount;
> >> unsigned int length;
> >> + struct zswap_pool *pool;
> >> unsigned long handle;
> >> };
> >>
> >> @@ -201,6 +156,44 @@ struct zswap_tree {
> >>
> >> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> >>
> >> +/* RCU-protected iteration */
> >> +static LIST_HEAD(zswap_pools);
> >> +/* protects zswap_pools list modification */
> >> +static DEFINE_SPINLOCK(zswap_pools_lock);
> >> +
> >> +/*********************************
> >> +* helpers and fwd declarations
> >> +**********************************/
> >> +
> >> +#define zswap_pool_debug(msg, p) \
> >> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> >> + zpool_get_type((p)->zpool))
> >> +
> >> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> >> +static int zswap_pool_get(struct zswap_pool *pool);
> >> +static void zswap_pool_put(struct zswap_pool *pool);
> >> +
> >> +static bool zswap_is_full(void)
> >> +{
> >> + return totalram_pages * zswap_max_pool_percent / 100 <
> >> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >> +}
> >> +
> >> +static void zswap_update_total_size(void)
> >> +{
> >> + struct zswap_pool *pool;
> >> + u64 total = 0;
> >> +
> >> + rcu_read_lock();
> >> +
> >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >> + total += zpool_get_total_size(pool->zpool);
> >> +
> >> + rcu_read_unlock();
> >> +
> >> + zswap_pool_total_size = total;
> >> +}
> >> +
> >> /*********************************
> >> * zswap entry functions
> >> **********************************/
> >> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> >> */
> >> static void zswap_free_entry(struct zswap_entry *entry)
> >> {
> >> - zpool_free(zswap_pool, entry->handle);
> >> + zpool_free(entry->pool->zpool, entry->handle);
> >> + zswap_pool_put(entry->pool);
> >> zswap_entry_cache_free(entry);
> >> atomic_dec(&zswap_stored_pages);
> >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >> + zswap_update_total_size();
> >> }
> >>
> >> /* caller must hold the tree lock */
> >> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> >> **********************************/
> >> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> >>
> >> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> >> {
> >> - struct crypto_comp *tfm;
> >> u8 *dst;
> >>
> >> switch (action) {
> >> case CPU_UP_PREPARE:
> >> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> >> - if (IS_ERR(tfm)) {
> >> - pr_err("can't allocate compressor transform\n");
> >> - return NOTIFY_BAD;
> >> - }
> >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> >> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> >> if (!dst) {
> >> pr_err("can't allocate compressor buffer\n");
> >> - crypto_free_comp(tfm);
> >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >> return NOTIFY_BAD;
> >> }
> >> per_cpu(zswap_dstmem, cpu) = dst;
> >> break;
> >> case CPU_DEAD:
> >> case CPU_UP_CANCELED:
> >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> >> - if (tfm) {
> >> - crypto_free_comp(tfm);
> >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >> - }
> >> dst = per_cpu(zswap_dstmem, cpu);
> >> kfree(dst);
> >> per_cpu(zswap_dstmem, cpu) = NULL;
> >> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >> return NOTIFY_OK;
> >> }
> >>
> >> -static int zswap_cpu_notifier(struct notifier_block *nb,
> >> - unsigned long action, void *pcpu)
> >> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> >> + unsigned long action, void *pcpu)
> >> {
> >> - unsigned long cpu = (unsigned long)pcpu;
> >> - return __zswap_cpu_notifier(action, cpu);
> >> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> >> }
> >>
> >> -static struct notifier_block zswap_cpu_notifier_block = {
> >> - .notifier_call = zswap_cpu_notifier
> >> +static struct notifier_block zswap_dstmem_notifier = {
> >> + .notifier_call = zswap_cpu_dstmem_notifier,
> >> };
> >>
> >> -static int __init zswap_cpu_init(void)
> >> +static int __init zswap_cpu_dstmem_init(void)
> >> {
> >> unsigned long cpu;
> >>
> >> cpu_notifier_register_begin();
> >> for_each_online_cpu(cpu)
> >> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> >> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> >> + NOTIFY_BAD)
> >> goto cleanup;
> >> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> >> + __register_cpu_notifier(&zswap_dstmem_notifier);
> >> cpu_notifier_register_done();
> >> return 0;
> >>
> >> cleanup:
> >> for_each_online_cpu(cpu)
> >> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >> cpu_notifier_register_done();
> >> return -ENOMEM;
> >> }
> >>
> >> +static void zswap_cpu_dstmem_destroy(void)
> >> +{
> >> + unsigned long cpu;
> >> +
> >> + cpu_notifier_register_begin();
> >> + for_each_online_cpu(cpu)
> >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> >> + cpu_notifier_register_done();
> >> +}
> >> +
> >> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> >> + unsigned long action, unsigned long cpu)
> >> +{
> >> + struct crypto_comp *tfm;
> >> +
> >> + switch (action) {
> >> + case CPU_UP_PREPARE:
> >> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> >> + break;
> >> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> >> + if (IS_ERR_OR_NULL(tfm)) {
> >> + pr_err("could not alloc crypto comp %s : %ld\n",
> >> + pool->tfm_name, PTR_ERR(tfm));
> >> + return NOTIFY_BAD;
> >> + }
> >> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> >> + break;
> >> + case CPU_DEAD:
> >> + case CPU_UP_CANCELED:
> >> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> >> + if (!IS_ERR_OR_NULL(tfm))
> >> + crypto_free_comp(tfm);
> >> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> >> + break;
> >> + default:
> >> + break;
> >> + }
> >> + return NOTIFY_OK;
> >> +}
> >> +
> >> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> >> + unsigned long action, void *pcpu)
> >> +{
> >> + unsigned long cpu = (unsigned long)pcpu;
> >> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> >> +
> >> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> >> +}
> >> +
> >> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> >> +{
> >> + unsigned long cpu;
> >> +
> >> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> >> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> >> +
> >> + cpu_notifier_register_begin();
> >> + for_each_online_cpu(cpu)
> >> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> >> + NOTIFY_BAD)
> >> + goto cleanup;
> >> + __register_cpu_notifier(&pool->notifier);
> >> + cpu_notifier_register_done();
> >> + return 0;
> >> +
> >> +cleanup:
> >> + for_each_online_cpu(cpu)
> >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >> + cpu_notifier_register_done();
> >> + return -ENOMEM;
> >> +}
> >> +
> >> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> >> +{
> >> + unsigned long cpu;
> >> +
> >> + cpu_notifier_register_begin();
> >> + for_each_online_cpu(cpu)
> >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >> + __unregister_cpu_notifier(&pool->notifier);
> >> + cpu_notifier_register_done();
> >> +}
> >> +
> >> /*********************************
> >> -* helpers
> >> +* pool functions
> >> **********************************/
> >> -static bool zswap_is_full(void)
> >> +
> >> +static struct zswap_pool *__zswap_pool_current(void)
> >> {
> >> - return totalram_pages * zswap_max_pool_percent / 100 <
> >> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >> + struct zswap_pool *pool;
> >> +
> >> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> >> + WARN_ON(!pool);
> >> +
> >> + return pool;
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_current(void)
> >> +{
> >> + assert_spin_locked(&zswap_pools_lock);
> >> +
> >> + return __zswap_pool_current();
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_current_get(void)
> >> +{
> >> + struct zswap_pool *pool;
> >> +
> >> + rcu_read_lock();
> >> +
> >> + pool = __zswap_pool_current();
> >> + if (!pool || !zswap_pool_get(pool))
> >> + pool = NULL;
> >> +
> >> + rcu_read_unlock();
> >> +
> >> + return pool;
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_last_get(void)
> >> +{
> >> + struct zswap_pool *pool, *last = NULL;
> >> +
> >> + rcu_read_lock();
> >> +
> >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >> + last = pool;
> >> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> >> + last = NULL;
> >> +
> >> + rcu_read_unlock();
> >> +
> >> + return last;
> >> +}
> >> +
> >> +static struct zpool_ops zswap_zpool_ops = {
> >> + .evict = zswap_writeback_entry
> >> +};
> >> +
> >> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> >> +{
> >> + struct zswap_pool *pool;
> >> +
> >> + assert_spin_locked(&zswap_pools_lock);
> >> +
> >> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> >> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> >> + continue;
> >> + if (strncmp(zpool_get_type(pool->zpool), type,
> >> + sizeof(zswap_zpool_type)))
> >> + continue;
> >> + /* if we can't get it, it's about to be destroyed */
> >> + if (!zswap_pool_get(pool))
> >> + continue;
> >> + return pool;
> >> + }
> >> +
> >> + return NULL;
> >> +}
> >> +
> >> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> >> +{
> >> + struct zswap_pool *pool;
> >> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >> +
> >> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> >> + if (!pool) {
> >> + pr_err("pool alloc failed\n");
> >> + return NULL;
> >> + }
> >> +
> >> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> >> + if (!pool->zpool) {
> >> + pr_err("%s zpool not available\n", type);
> >> + goto error;
> >> + }
> >> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> >> +
> >> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> >> + pool->tfm = alloc_percpu(struct crypto_comp *);
> >> + if (!pool->tfm) {
> >> + pr_err("percpu alloc failed\n");
> >> + goto error;
> >> + }
> >> +
> >> + if (zswap_cpu_comp_init(pool))
> >> + goto error;
> >> + pr_debug("using %s compressor\n", pool->tfm_name);
> >> +
> >> + /* being the current pool takes 1 ref; this func expects the
> >> + * caller to always add the new pool as the current pool
> >> + */
> >> + kref_init(&pool->kref);
> >> + INIT_LIST_HEAD(&pool->list);
> >> +
> >> + zswap_pool_debug("created", pool);
> >> +
> >> + return pool;
> >> +
> >> +error:
> >> + free_percpu(pool->tfm);
> >> + if (pool->zpool)
> >> + zpool_destroy_pool(pool->zpool);
> >> + kfree(pool);
> >> + return NULL;
> >> +}
> >> +
> >> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> >> +{
> >> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >> + pr_err("compressor %s not available, using default %s\n",
> >> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> >> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> >> + sizeof(zswap_compressor));
> >> + }
> >> + if (!zpool_has_pool(zswap_zpool_type)) {
> >> + pr_err("zpool %s not available, using default %s\n",
> >> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> >> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> >> + sizeof(zswap_zpool_type));
> >> + }
> >> +
> >> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> >> +}
> >> +
> >> +static void zswap_pool_destroy(struct zswap_pool *pool)
> >> +{
> >> + zswap_pool_debug("destroying", pool);
> >> +
> >> + zswap_cpu_comp_destroy(pool);
> >> + free_percpu(pool->tfm);
> >> + zpool_destroy_pool(pool->zpool);
> >> + kfree(pool);
> >> +}
> >> +
> >> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> >> +{
> >> + return kref_get_unless_zero(&pool->kref);
> >> +}
> >> +
> >> +static void __zswap_pool_release(struct rcu_head *head)
> >> +{
> >> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> >> +
> >> + /* nobody should have been able to get a kref... */
> >> + WARN_ON(kref_get_unless_zero(&pool->kref));
> >> +
> >> + /* pool is now off zswap_pools list and has no references. */
> >> + zswap_pool_destroy(pool);
> >> +}
> >> +
> >> +static void __zswap_pool_empty(struct kref *kref)
> >> +{
> >> + struct zswap_pool *pool;
> >> +
> >> + pool = container_of(kref, typeof(*pool), kref);
> >> +
> >> + spin_lock(&zswap_pools_lock);
> >> +
> >> + WARN_ON(pool == zswap_pool_current());
> >> +
> >> + list_del_rcu(&pool->list);
> >> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> >> +
> >> + spin_unlock(&zswap_pools_lock);
> >> +}
> >> +
> >> +static void zswap_pool_put(struct zswap_pool *pool)
> >> +{
> >> + kref_put(&pool->kref, __zswap_pool_empty);
> >> +}
> >> +
> >> }
> >>
> >> /*********************************
> >> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >> pgoff_t offset;
> >> struct zswap_entry *entry;
> >> struct page *page;
> >> + struct crypto_comp *tfm;
> >> u8 *src, *dst;
> >> unsigned int dlen;
> >> int ret;
> >> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> >> /* decompress */
> >> dlen = PAGE_SIZE;
> >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >> dst = kmap_atomic(page);
> >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> >> - entry->length, dst, &dlen);
> >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >> + ret = crypto_comp_decompress(tfm, src, entry->length,
> >> + dst, &dlen);
> >> + put_cpu_ptr(entry->pool->tfm);
> >> kunmap_atomic(dst);
> >> - zpool_unmap_handle(zswap_pool, entry->handle);
> >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >> BUG_ON(ret);
> >> BUG_ON(dlen != PAGE_SIZE);
> >>
> >> @@ -633,6 +882,22 @@ end:
> >> return ret;
> >> }
> >>
> >> +static int zswap_shrink(void)
> >> +{
> >> + struct zswap_pool *pool;
> >> + int ret;
> >> +
> >> + pool = zswap_pool_last_get();
> >> + if (!pool)
> >> + return -ENOENT;
> >> +
> >> + ret = zpool_shrink(pool->zpool, 1, NULL);
> >> +
> >> + zswap_pool_put(pool);
> >> +
> >> + return ret;
> >> +}
> >> +
> >> /*********************************
> >> * frontswap hooks
> >> **********************************/
> >> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >> {
> >> struct zswap_tree *tree = zswap_trees[type];
> >> struct zswap_entry *entry, *dupentry;
> >> + struct crypto_comp *tfm;
> >> int ret;
> >> unsigned int dlen = PAGE_SIZE, len;
> >> unsigned long handle;
> >> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >> /* reclaim space if needed */
> >> if (zswap_is_full()) {
> >> zswap_pool_limit_hit++;
> >> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> >> + if (zswap_shrink()) {
> >> zswap_reject_reclaim_fail++;
> >> ret = -ENOMEM;
> >> goto reject;
> >> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >> goto reject;
> >> }
> >>
> >> + /* if entry is successfully added, it keeps the reference */
> >> + entry->pool = zswap_pool_current_get();
> >> + if (!entry->pool) {
> >> + ret = -EINVAL;
> >> + goto freepage;
> >> + }
> >> +
> >> /* compress */
> >> dst = get_cpu_var(zswap_dstmem);
> >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >> src = kmap_atomic(page);
> >> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> >> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> >> kunmap_atomic(src);
> >> + put_cpu_ptr(entry->pool->tfm);
> >> if (ret) {
> >> ret = -EINVAL;
> >> - goto freepage;
> >> + goto put_dstmem;
> >> }
> >>
> >> /* store */
> >> len = dlen + sizeof(struct zswap_header);
> >> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> >> - &handle);
> >> + ret = zpool_malloc(entry->pool->zpool, len,
> >> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> >> if (ret == -ENOSPC) {
> >> zswap_reject_compress_poor++;
> >> - goto freepage;
> >> + goto put_dstmem;
> >> }
> >> if (ret) {
> >> zswap_reject_alloc_fail++;
> >> - goto freepage;
> >> + goto put_dstmem;
> >> }
> >> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> >> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> >> zhdr->swpentry = swp_entry(type, offset);
> >> buf = (u8 *)(zhdr + 1);
> >> memcpy(buf, dst, dlen);
> >> - zpool_unmap_handle(zswap_pool, handle);
> >> + zpool_unmap_handle(entry->pool->zpool, handle);
> >> put_cpu_var(zswap_dstmem);
> >>
> >> /* populate entry */
> >> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>
> >> /* update stats */
> >> atomic_inc(&zswap_stored_pages);
> >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >> + zswap_update_total_size();
> >>
> >> return 0;
> >>
> >> -freepage:
> >> +put_dstmem:
> >> put_cpu_var(zswap_dstmem);
> >> + zswap_pool_put(entry->pool);
> >> +freepage:
> >> zswap_entry_cache_free(entry);
> >> reject:
> >> return ret;
> >> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >> {
> >> struct zswap_tree *tree = zswap_trees[type];
> >> struct zswap_entry *entry;
> >> + struct crypto_comp *tfm;
> >> u8 *src, *dst;
> >> unsigned int dlen;
> >> int ret;
> >> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>
> >> /* decompress */
> >> dlen = PAGE_SIZE;
> >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >> dst = kmap_atomic(page);
> >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> >> - dst, &dlen);
> >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> >> + put_cpu_ptr(entry->pool->tfm);
> >> kunmap_atomic(dst);
> >> - zpool_unmap_handle(zswap_pool, entry->handle);
> >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >> BUG_ON(ret);
> >>
> >> spin_lock(&tree->lock);
> >> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> >> zswap_trees[type] = NULL;
> >> }
> >>
> >> -static struct zpool_ops zswap_zpool_ops = {
> >> - .evict = zswap_writeback_entry
> >> -};
> >> -
> >> static void zswap_frontswap_init(unsigned type)
> >> {
> >> struct zswap_tree *tree;
> >> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> >> **********************************/
> >> static int __init init_zswap(void)
> >> {
> >> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >> + struct zswap_pool *pool;
> >>
> >> - pr_info("loading zswap\n");
> >> -
> >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >> - &zswap_zpool_ops);
> >> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> >> - pr_info("%s zpool not available\n", zswap_zpool_type);
> >> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >> - &zswap_zpool_ops);
> >> - }
> >> - if (!zswap_pool) {
> >> - pr_err("%s zpool not available\n", zswap_zpool_type);
> >> - pr_err("zpool creation failed\n");
> >> - goto error;
> >> - }
> >> - pr_info("using %s pool\n", zswap_zpool_type);
> >> + pr_info("loading\n");
> >>
> >> if (zswap_entry_cache_create()) {
> >> pr_err("entry cache creation failed\n");
> >> - goto cachefail;
> >> + goto cache_fail;
> >> }
> >> - if (zswap_comp_init()) {
> >> - pr_err("compressor initialization failed\n");
> >> - goto compfail;
> >> +
> >> + if (zswap_cpu_dstmem_init()) {
> >> + pr_err("dstmem alloc failed\n");
> >> + goto dstmem_fail;
> >> }
> >> - if (zswap_cpu_init()) {
> >> - pr_err("per-cpu initialization failed\n");
> >> - goto pcpufail;
> >> +
> >> + pool = __zswap_pool_create_fallback();
> >> + if (!pool) {
> >> + pr_err("pool creation failed\n");
> >> + goto pool_fail;
> >> }
> >> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> >> + zpool_get_type(pool->zpool));
> >> +
> >> + list_add(&pool->list, &zswap_pools);
> >>
> >> frontswap_register_ops(&zswap_frontswap_ops);
> >> if (zswap_debugfs_init())
> >> pr_warn("debugfs initialization failed\n");
> >> return 0;
> >> -pcpufail:
> >> - zswap_comp_exit();
> >> -compfail:
> >> +
> >> +pool_fail:
> >> + zswap_cpu_dstmem_destroy();
> >> +dstmem_fail:
> >> zswap_entry_cache_destroy();
> >> -cachefail:
> >> - zpool_destroy_pool(zswap_pool);
> >> -error:
> >> +cache_fail:
> >> return -ENOMEM;
> >> }
> >> /* must be late so crypto has time to come up */
> >> --
> >> 2.1.0
> >>
--
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-10 20:54 ` Dan Streetman
@ 2015-06-17 23:13 ` Dan Streetman
-1 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-17 23:13 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Wed, Jun 10, 2015 at 4:54 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>>> Add dynamic creation of pools. Move the static crypto compression
>>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
>>> the pool it's in.
>>
>> Seth, as far as the design, from your previous comments I assume you
>> were thinking of maintaining separate lists of zpools and compressors?
>> I do see how that will reduce duplication of zpools and compressors,
>> but it also requires adding a new pointer to each zswap_entry, and
>> increasing the amount of code to manage each list separately. And the
>> most common case in zswap will be just a single zpool and compressor,
>> not repeatedly changing params. What do you think?
>
> Any opinion on this patch? If you want, I can break it up so there's
> a list of zpools and a list of compressors. Either the combined way
> (this patch) or separate lists works for me, as long as the params are
> changeable at runtime :-)
You on vacation Seth? Let me know what direction you prefer for this...
>
>
>>
>>>
>>> This is required by a separate patch which enables changing the
>>> zswap zpool and compressor params at runtime.
>>>
>>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
>>> ---
>>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
>>> 1 file changed, 408 insertions(+), 142 deletions(-)
>>>
>>> diff --git a/mm/zswap.c b/mm/zswap.c
>>> index 2d5727b..fc93770 100644
>>> --- a/mm/zswap.c
>>> +++ b/mm/zswap.c
>>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
>>> static struct zpool *zswap_pool;
>>>
>>> /*********************************
>>> -* compression functions
>>> +* data structures
>>> **********************************/
>>> -/* per-cpu compression transforms */
>>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>>>
>>> -enum comp_op {
>>> - ZSWAP_COMPOP_COMPRESS,
>>> - ZSWAP_COMPOP_DECOMPRESS
>>> +struct zswap_pool {
>>> + struct zpool *zpool;
>>> + struct kref kref;
>>> + struct list_head list;
>>> + struct rcu_head rcu_head;
>>> + struct notifier_block notifier;
>>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
>>> + struct crypto_comp * __percpu *tfm;
>>> };
>>>
>>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
>>> - u8 *dst, unsigned int *dlen)
>>> -{
>>> - struct crypto_comp *tfm;
>>> - int ret;
>>> -
>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
>>> - switch (op) {
>>> - case ZSWAP_COMPOP_COMPRESS:
>>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
>>> - break;
>>> - case ZSWAP_COMPOP_DECOMPRESS:
>>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
>>> - break;
>>> - default:
>>> - ret = -EINVAL;
>>> - }
>>> -
>>> - put_cpu();
>>> - return ret;
>>> -}
>>> -
>>> -static int __init zswap_comp_init(void)
>>> -{
>>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>> - pr_info("%s compressor not available\n", zswap_compressor);
>>> - /* fall back to default compressor */
>>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
>>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
>>> - /* can't even load the default compressor */
>>> - return -ENODEV;
>>> - }
>>> - pr_info("using %s compressor\n", zswap_compressor);
>>> -
>>> - /* alloc percpu transforms */
>>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
>>> - if (!zswap_comp_pcpu_tfms)
>>> - return -ENOMEM;
>>> - return 0;
>>> -}
>>> -
>>> -static void __init zswap_comp_exit(void)
>>> -{
>>> - /* free percpu transforms */
>>> - free_percpu(zswap_comp_pcpu_tfms);
>>> -}
>>> -
>>> -/*********************************
>>> -* data structures
>>> -**********************************/
>>> /*
>>> * struct zswap_entry
>>> *
>>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
>>> * page within zswap.
>>> *
>>> * rbnode - links the entry into red-black tree for the appropriate swap type
>>> + * offset - the swap offset for the entry. Index into the red-black tree.
>>> * refcount - the number of outstanding reference to the entry. This is needed
>>> * to protect against premature freeing of the entry by code
>>> * concurrent calls to load, invalidate, and writeback. The lock
>>> * for the zswap_tree structure that contains the entry must
>>> * be held while changing the refcount. Since the lock must
>>> * be held, there is no reason to also make refcount atomic.
>>> - * offset - the swap offset for the entry. Index into the red-black tree.
>>> - * handle - zpool allocation handle that stores the compressed page data
>>> * length - the length in bytes of the compressed page data. Needed during
>>> * decompression
>>> + * pool - the zswap_pool the entry's data is in
>>> + * handle - zpool allocation handle that stores the compressed page data
>>> */
>>> struct zswap_entry {
>>> struct rb_node rbnode;
>>> pgoff_t offset;
>>> int refcount;
>>> unsigned int length;
>>> + struct zswap_pool *pool;
>>> unsigned long handle;
>>> };
>>>
>>> @@ -201,6 +156,44 @@ struct zswap_tree {
>>>
>>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>>>
>>> +/* RCU-protected iteration */
>>> +static LIST_HEAD(zswap_pools);
>>> +/* protects zswap_pools list modification */
>>> +static DEFINE_SPINLOCK(zswap_pools_lock);
>>> +
>>> +/*********************************
>>> +* helpers and fwd declarations
>>> +**********************************/
>>> +
>>> +#define zswap_pool_debug(msg, p) \
>>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
>>> + zpool_get_type((p)->zpool))
>>> +
>>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
>>> +static int zswap_pool_get(struct zswap_pool *pool);
>>> +static void zswap_pool_put(struct zswap_pool *pool);
>>> +
>>> +static bool zswap_is_full(void)
>>> +{
>>> + return totalram_pages * zswap_max_pool_percent / 100 <
>>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>> +}
>>> +
>>> +static void zswap_update_total_size(void)
>>> +{
>>> + struct zswap_pool *pool;
>>> + u64 total = 0;
>>> +
>>> + rcu_read_lock();
>>> +
>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>> + total += zpool_get_total_size(pool->zpool);
>>> +
>>> + rcu_read_unlock();
>>> +
>>> + zswap_pool_total_size = total;
>>> +}
>>> +
>>> /*********************************
>>> * zswap entry functions
>>> **********************************/
>>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
>>> */
>>> static void zswap_free_entry(struct zswap_entry *entry)
>>> {
>>> - zpool_free(zswap_pool, entry->handle);
>>> + zpool_free(entry->pool->zpool, entry->handle);
>>> + zswap_pool_put(entry->pool);
>>> zswap_entry_cache_free(entry);
>>> atomic_dec(&zswap_stored_pages);
>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>> + zswap_update_total_size();
>>> }
>>>
>>> /* caller must hold the tree lock */
>>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
>>> **********************************/
>>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>>>
>>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
>>> {
>>> - struct crypto_comp *tfm;
>>> u8 *dst;
>>>
>>> switch (action) {
>>> case CPU_UP_PREPARE:
>>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
>>> - if (IS_ERR(tfm)) {
>>> - pr_err("can't allocate compressor transform\n");
>>> - return NOTIFY_BAD;
>>> - }
>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
>>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
>>> if (!dst) {
>>> pr_err("can't allocate compressor buffer\n");
>>> - crypto_free_comp(tfm);
>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>> return NOTIFY_BAD;
>>> }
>>> per_cpu(zswap_dstmem, cpu) = dst;
>>> break;
>>> case CPU_DEAD:
>>> case CPU_UP_CANCELED:
>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
>>> - if (tfm) {
>>> - crypto_free_comp(tfm);
>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>> - }
>>> dst = per_cpu(zswap_dstmem, cpu);
>>> kfree(dst);
>>> per_cpu(zswap_dstmem, cpu) = NULL;
>>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>> return NOTIFY_OK;
>>> }
>>>
>>> -static int zswap_cpu_notifier(struct notifier_block *nb,
>>> - unsigned long action, void *pcpu)
>>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
>>> + unsigned long action, void *pcpu)
>>> {
>>> - unsigned long cpu = (unsigned long)pcpu;
>>> - return __zswap_cpu_notifier(action, cpu);
>>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
>>> }
>>>
>>> -static struct notifier_block zswap_cpu_notifier_block = {
>>> - .notifier_call = zswap_cpu_notifier
>>> +static struct notifier_block zswap_dstmem_notifier = {
>>> + .notifier_call = zswap_cpu_dstmem_notifier,
>>> };
>>>
>>> -static int __init zswap_cpu_init(void)
>>> +static int __init zswap_cpu_dstmem_init(void)
>>> {
>>> unsigned long cpu;
>>>
>>> cpu_notifier_register_begin();
>>> for_each_online_cpu(cpu)
>>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
>>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
>>> + NOTIFY_BAD)
>>> goto cleanup;
>>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
>>> + __register_cpu_notifier(&zswap_dstmem_notifier);
>>> cpu_notifier_register_done();
>>> return 0;
>>>
>>> cleanup:
>>> for_each_online_cpu(cpu)
>>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>> cpu_notifier_register_done();
>>> return -ENOMEM;
>>> }
>>>
>>> +static void zswap_cpu_dstmem_destroy(void)
>>> +{
>>> + unsigned long cpu;
>>> +
>>> + cpu_notifier_register_begin();
>>> + for_each_online_cpu(cpu)
>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
>>> + cpu_notifier_register_done();
>>> +}
>>> +
>>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
>>> + unsigned long action, unsigned long cpu)
>>> +{
>>> + struct crypto_comp *tfm;
>>> +
>>> + switch (action) {
>>> + case CPU_UP_PREPARE:
>>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
>>> + break;
>>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
>>> + if (IS_ERR_OR_NULL(tfm)) {
>>> + pr_err("could not alloc crypto comp %s : %ld\n",
>>> + pool->tfm_name, PTR_ERR(tfm));
>>> + return NOTIFY_BAD;
>>> + }
>>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
>>> + break;
>>> + case CPU_DEAD:
>>> + case CPU_UP_CANCELED:
>>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
>>> + if (!IS_ERR_OR_NULL(tfm))
>>> + crypto_free_comp(tfm);
>>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
>>> + break;
>>> + default:
>>> + break;
>>> + }
>>> + return NOTIFY_OK;
>>> +}
>>> +
>>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
>>> + unsigned long action, void *pcpu)
>>> +{
>>> + unsigned long cpu = (unsigned long)pcpu;
>>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
>>> +
>>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
>>> +}
>>> +
>>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
>>> +{
>>> + unsigned long cpu;
>>> +
>>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
>>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
>>> +
>>> + cpu_notifier_register_begin();
>>> + for_each_online_cpu(cpu)
>>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
>>> + NOTIFY_BAD)
>>> + goto cleanup;
>>> + __register_cpu_notifier(&pool->notifier);
>>> + cpu_notifier_register_done();
>>> + return 0;
>>> +
>>> +cleanup:
>>> + for_each_online_cpu(cpu)
>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>> + cpu_notifier_register_done();
>>> + return -ENOMEM;
>>> +}
>>> +
>>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
>>> +{
>>> + unsigned long cpu;
>>> +
>>> + cpu_notifier_register_begin();
>>> + for_each_online_cpu(cpu)
>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>> + __unregister_cpu_notifier(&pool->notifier);
>>> + cpu_notifier_register_done();
>>> +}
>>> +
>>> /*********************************
>>> -* helpers
>>> +* pool functions
>>> **********************************/
>>> -static bool zswap_is_full(void)
>>> +
>>> +static struct zswap_pool *__zswap_pool_current(void)
>>> {
>>> - return totalram_pages * zswap_max_pool_percent / 100 <
>>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>> + struct zswap_pool *pool;
>>> +
>>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
>>> + WARN_ON(!pool);
>>> +
>>> + return pool;
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_current(void)
>>> +{
>>> + assert_spin_locked(&zswap_pools_lock);
>>> +
>>> + return __zswap_pool_current();
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_current_get(void)
>>> +{
>>> + struct zswap_pool *pool;
>>> +
>>> + rcu_read_lock();
>>> +
>>> + pool = __zswap_pool_current();
>>> + if (!pool || !zswap_pool_get(pool))
>>> + pool = NULL;
>>> +
>>> + rcu_read_unlock();
>>> +
>>> + return pool;
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_last_get(void)
>>> +{
>>> + struct zswap_pool *pool, *last = NULL;
>>> +
>>> + rcu_read_lock();
>>> +
>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>> + last = pool;
>>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
>>> + last = NULL;
>>> +
>>> + rcu_read_unlock();
>>> +
>>> + return last;
>>> +}
>>> +
>>> +static struct zpool_ops zswap_zpool_ops = {
>>> + .evict = zswap_writeback_entry
>>> +};
>>> +
>>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
>>> +{
>>> + struct zswap_pool *pool;
>>> +
>>> + assert_spin_locked(&zswap_pools_lock);
>>> +
>>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
>>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
>>> + continue;
>>> + if (strncmp(zpool_get_type(pool->zpool), type,
>>> + sizeof(zswap_zpool_type)))
>>> + continue;
>>> + /* if we can't get it, it's about to be destroyed */
>>> + if (!zswap_pool_get(pool))
>>> + continue;
>>> + return pool;
>>> + }
>>> +
>>> + return NULL;
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
>>> +{
>>> + struct zswap_pool *pool;
>>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>> +
>>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
>>> + if (!pool) {
>>> + pr_err("pool alloc failed\n");
>>> + return NULL;
>>> + }
>>> +
>>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
>>> + if (!pool->zpool) {
>>> + pr_err("%s zpool not available\n", type);
>>> + goto error;
>>> + }
>>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
>>> +
>>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
>>> + pool->tfm = alloc_percpu(struct crypto_comp *);
>>> + if (!pool->tfm) {
>>> + pr_err("percpu alloc failed\n");
>>> + goto error;
>>> + }
>>> +
>>> + if (zswap_cpu_comp_init(pool))
>>> + goto error;
>>> + pr_debug("using %s compressor\n", pool->tfm_name);
>>> +
>>> + /* being the current pool takes 1 ref; this func expects the
>>> + * caller to always add the new pool as the current pool
>>> + */
>>> + kref_init(&pool->kref);
>>> + INIT_LIST_HEAD(&pool->list);
>>> +
>>> + zswap_pool_debug("created", pool);
>>> +
>>> + return pool;
>>> +
>>> +error:
>>> + free_percpu(pool->tfm);
>>> + if (pool->zpool)
>>> + zpool_destroy_pool(pool->zpool);
>>> + kfree(pool);
>>> + return NULL;
>>> +}
>>> +
>>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
>>> +{
>>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>> + pr_err("compressor %s not available, using default %s\n",
>>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
>>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
>>> + sizeof(zswap_compressor));
>>> + }
>>> + if (!zpool_has_pool(zswap_zpool_type)) {
>>> + pr_err("zpool %s not available, using default %s\n",
>>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
>>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
>>> + sizeof(zswap_zpool_type));
>>> + }
>>> +
>>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
>>> +}
>>> +
>>> +static void zswap_pool_destroy(struct zswap_pool *pool)
>>> +{
>>> + zswap_pool_debug("destroying", pool);
>>> +
>>> + zswap_cpu_comp_destroy(pool);
>>> + free_percpu(pool->tfm);
>>> + zpool_destroy_pool(pool->zpool);
>>> + kfree(pool);
>>> +}
>>> +
>>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
>>> +{
>>> + return kref_get_unless_zero(&pool->kref);
>>> +}
>>> +
>>> +static void __zswap_pool_release(struct rcu_head *head)
>>> +{
>>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
>>> +
>>> + /* nobody should have been able to get a kref... */
>>> + WARN_ON(kref_get_unless_zero(&pool->kref));
>>> +
>>> + /* pool is now off zswap_pools list and has no references. */
>>> + zswap_pool_destroy(pool);
>>> +}
>>> +
>>> +static void __zswap_pool_empty(struct kref *kref)
>>> +{
>>> + struct zswap_pool *pool;
>>> +
>>> + pool = container_of(kref, typeof(*pool), kref);
>>> +
>>> + spin_lock(&zswap_pools_lock);
>>> +
>>> + WARN_ON(pool == zswap_pool_current());
>>> +
>>> + list_del_rcu(&pool->list);
>>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
>>> +
>>> + spin_unlock(&zswap_pools_lock);
>>> +}
>>> +
>>> +static void zswap_pool_put(struct zswap_pool *pool)
>>> +{
>>> + kref_put(&pool->kref, __zswap_pool_empty);
>>> +}
>>> +
>>> }
>>>
>>> /*********************************
>>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>> pgoff_t offset;
>>> struct zswap_entry *entry;
>>> struct page *page;
>>> + struct crypto_comp *tfm;
>>> u8 *src, *dst;
>>> unsigned int dlen;
>>> int ret;
>>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
>>> /* decompress */
>>> dlen = PAGE_SIZE;
>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>> dst = kmap_atomic(page);
>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
>>> - entry->length, dst, &dlen);
>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>> + ret = crypto_comp_decompress(tfm, src, entry->length,
>>> + dst, &dlen);
>>> + put_cpu_ptr(entry->pool->tfm);
>>> kunmap_atomic(dst);
>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>> BUG_ON(ret);
>>> BUG_ON(dlen != PAGE_SIZE);
>>>
>>> @@ -633,6 +882,22 @@ end:
>>> return ret;
>>> }
>>>
>>> +static int zswap_shrink(void)
>>> +{
>>> + struct zswap_pool *pool;
>>> + int ret;
>>> +
>>> + pool = zswap_pool_last_get();
>>> + if (!pool)
>>> + return -ENOENT;
>>> +
>>> + ret = zpool_shrink(pool->zpool, 1, NULL);
>>> +
>>> + zswap_pool_put(pool);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> /*********************************
>>> * frontswap hooks
>>> **********************************/
>>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>> {
>>> struct zswap_tree *tree = zswap_trees[type];
>>> struct zswap_entry *entry, *dupentry;
>>> + struct crypto_comp *tfm;
>>> int ret;
>>> unsigned int dlen = PAGE_SIZE, len;
>>> unsigned long handle;
>>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>> /* reclaim space if needed */
>>> if (zswap_is_full()) {
>>> zswap_pool_limit_hit++;
>>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
>>> + if (zswap_shrink()) {
>>> zswap_reject_reclaim_fail++;
>>> ret = -ENOMEM;
>>> goto reject;
>>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>> goto reject;
>>> }
>>>
>>> + /* if entry is successfully added, it keeps the reference */
>>> + entry->pool = zswap_pool_current_get();
>>> + if (!entry->pool) {
>>> + ret = -EINVAL;
>>> + goto freepage;
>>> + }
>>> +
>>> /* compress */
>>> dst = get_cpu_var(zswap_dstmem);
>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>> src = kmap_atomic(page);
>>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
>>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
>>> kunmap_atomic(src);
>>> + put_cpu_ptr(entry->pool->tfm);
>>> if (ret) {
>>> ret = -EINVAL;
>>> - goto freepage;
>>> + goto put_dstmem;
>>> }
>>>
>>> /* store */
>>> len = dlen + sizeof(struct zswap_header);
>>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
>>> - &handle);
>>> + ret = zpool_malloc(entry->pool->zpool, len,
>>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
>>> if (ret == -ENOSPC) {
>>> zswap_reject_compress_poor++;
>>> - goto freepage;
>>> + goto put_dstmem;
>>> }
>>> if (ret) {
>>> zswap_reject_alloc_fail++;
>>> - goto freepage;
>>> + goto put_dstmem;
>>> }
>>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
>>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
>>> zhdr->swpentry = swp_entry(type, offset);
>>> buf = (u8 *)(zhdr + 1);
>>> memcpy(buf, dst, dlen);
>>> - zpool_unmap_handle(zswap_pool, handle);
>>> + zpool_unmap_handle(entry->pool->zpool, handle);
>>> put_cpu_var(zswap_dstmem);
>>>
>>> /* populate entry */
>>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>
>>> /* update stats */
>>> atomic_inc(&zswap_stored_pages);
>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>> + zswap_update_total_size();
>>>
>>> return 0;
>>>
>>> -freepage:
>>> +put_dstmem:
>>> put_cpu_var(zswap_dstmem);
>>> + zswap_pool_put(entry->pool);
>>> +freepage:
>>> zswap_entry_cache_free(entry);
>>> reject:
>>> return ret;
>>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>> {
>>> struct zswap_tree *tree = zswap_trees[type];
>>> struct zswap_entry *entry;
>>> + struct crypto_comp *tfm;
>>> u8 *src, *dst;
>>> unsigned int dlen;
>>> int ret;
>>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>>
>>> /* decompress */
>>> dlen = PAGE_SIZE;
>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>> dst = kmap_atomic(page);
>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
>>> - dst, &dlen);
>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
>>> + put_cpu_ptr(entry->pool->tfm);
>>> kunmap_atomic(dst);
>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>> BUG_ON(ret);
>>>
>>> spin_lock(&tree->lock);
>>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
>>> zswap_trees[type] = NULL;
>>> }
>>>
>>> -static struct zpool_ops zswap_zpool_ops = {
>>> - .evict = zswap_writeback_entry
>>> -};
>>> -
>>> static void zswap_frontswap_init(unsigned type)
>>> {
>>> struct zswap_tree *tree;
>>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
>>> **********************************/
>>> static int __init init_zswap(void)
>>> {
>>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>> + struct zswap_pool *pool;
>>>
>>> - pr_info("loading zswap\n");
>>> -
>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>> - &zswap_zpool_ops);
>>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
>>> - pr_info("%s zpool not available\n", zswap_zpool_type);
>>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>> - &zswap_zpool_ops);
>>> - }
>>> - if (!zswap_pool) {
>>> - pr_err("%s zpool not available\n", zswap_zpool_type);
>>> - pr_err("zpool creation failed\n");
>>> - goto error;
>>> - }
>>> - pr_info("using %s pool\n", zswap_zpool_type);
>>> + pr_info("loading\n");
>>>
>>> if (zswap_entry_cache_create()) {
>>> pr_err("entry cache creation failed\n");
>>> - goto cachefail;
>>> + goto cache_fail;
>>> }
>>> - if (zswap_comp_init()) {
>>> - pr_err("compressor initialization failed\n");
>>> - goto compfail;
>>> +
>>> + if (zswap_cpu_dstmem_init()) {
>>> + pr_err("dstmem alloc failed\n");
>>> + goto dstmem_fail;
>>> }
>>> - if (zswap_cpu_init()) {
>>> - pr_err("per-cpu initialization failed\n");
>>> - goto pcpufail;
>>> +
>>> + pool = __zswap_pool_create_fallback();
>>> + if (!pool) {
>>> + pr_err("pool creation failed\n");
>>> + goto pool_fail;
>>> }
>>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
>>> + zpool_get_type(pool->zpool));
>>> +
>>> + list_add(&pool->list, &zswap_pools);
>>>
>>> frontswap_register_ops(&zswap_frontswap_ops);
>>> if (zswap_debugfs_init())
>>> pr_warn("debugfs initialization failed\n");
>>> return 0;
>>> -pcpufail:
>>> - zswap_comp_exit();
>>> -compfail:
>>> +
>>> +pool_fail:
>>> + zswap_cpu_dstmem_destroy();
>>> +dstmem_fail:
>>> zswap_entry_cache_destroy();
>>> -cachefail:
>>> - zpool_destroy_pool(zswap_pool);
>>> -error:
>>> +cache_fail:
>>> return -ENOMEM;
>>> }
>>> /* must be late so crypto has time to come up */
>>> --
>>> 2.1.0
>>>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-17 23:13 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-17 23:13 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Wed, Jun 10, 2015 at 4:54 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>>> Add dynamic creation of pools. Move the static crypto compression
>>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
>>> the pool it's in.
>>
>> Seth, as far as the design, from your previous comments I assume you
>> were thinking of maintaining separate lists of zpools and compressors?
>> I do see how that will reduce duplication of zpools and compressors,
>> but it also requires adding a new pointer to each zswap_entry, and
>> increasing the amount of code to manage each list separately. And the
>> most common case in zswap will be just a single zpool and compressor,
>> not repeatedly changing params. What do you think?
>
> Any opinion on this patch? If you want, I can break it up so there's
> a list of zpools and a list of compressors. Either the combined way
> (this patch) or separate lists works for me, as long as the params are
> changeable at runtime :-)
You on vacation Seth? Let me know what direction you prefer for this...
>
>
>>
>>>
>>> This is required by a separate patch which enables changing the
>>> zswap zpool and compressor params at runtime.
>>>
>>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
>>> ---
>>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
>>> 1 file changed, 408 insertions(+), 142 deletions(-)
>>>
>>> diff --git a/mm/zswap.c b/mm/zswap.c
>>> index 2d5727b..fc93770 100644
>>> --- a/mm/zswap.c
>>> +++ b/mm/zswap.c
>>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
>>> static struct zpool *zswap_pool;
>>>
>>> /*********************************
>>> -* compression functions
>>> +* data structures
>>> **********************************/
>>> -/* per-cpu compression transforms */
>>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>>>
>>> -enum comp_op {
>>> - ZSWAP_COMPOP_COMPRESS,
>>> - ZSWAP_COMPOP_DECOMPRESS
>>> +struct zswap_pool {
>>> + struct zpool *zpool;
>>> + struct kref kref;
>>> + struct list_head list;
>>> + struct rcu_head rcu_head;
>>> + struct notifier_block notifier;
>>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
>>> + struct crypto_comp * __percpu *tfm;
>>> };
>>>
>>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
>>> - u8 *dst, unsigned int *dlen)
>>> -{
>>> - struct crypto_comp *tfm;
>>> - int ret;
>>> -
>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
>>> - switch (op) {
>>> - case ZSWAP_COMPOP_COMPRESS:
>>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
>>> - break;
>>> - case ZSWAP_COMPOP_DECOMPRESS:
>>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
>>> - break;
>>> - default:
>>> - ret = -EINVAL;
>>> - }
>>> -
>>> - put_cpu();
>>> - return ret;
>>> -}
>>> -
>>> -static int __init zswap_comp_init(void)
>>> -{
>>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>> - pr_info("%s compressor not available\n", zswap_compressor);
>>> - /* fall back to default compressor */
>>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
>>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
>>> - /* can't even load the default compressor */
>>> - return -ENODEV;
>>> - }
>>> - pr_info("using %s compressor\n", zswap_compressor);
>>> -
>>> - /* alloc percpu transforms */
>>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
>>> - if (!zswap_comp_pcpu_tfms)
>>> - return -ENOMEM;
>>> - return 0;
>>> -}
>>> -
>>> -static void __init zswap_comp_exit(void)
>>> -{
>>> - /* free percpu transforms */
>>> - free_percpu(zswap_comp_pcpu_tfms);
>>> -}
>>> -
>>> -/*********************************
>>> -* data structures
>>> -**********************************/
>>> /*
>>> * struct zswap_entry
>>> *
>>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
>>> * page within zswap.
>>> *
>>> * rbnode - links the entry into red-black tree for the appropriate swap type
>>> + * offset - the swap offset for the entry. Index into the red-black tree.
>>> * refcount - the number of outstanding reference to the entry. This is needed
>>> * to protect against premature freeing of the entry by code
>>> * concurrent calls to load, invalidate, and writeback. The lock
>>> * for the zswap_tree structure that contains the entry must
>>> * be held while changing the refcount. Since the lock must
>>> * be held, there is no reason to also make refcount atomic.
>>> - * offset - the swap offset for the entry. Index into the red-black tree.
>>> - * handle - zpool allocation handle that stores the compressed page data
>>> * length - the length in bytes of the compressed page data. Needed during
>>> * decompression
>>> + * pool - the zswap_pool the entry's data is in
>>> + * handle - zpool allocation handle that stores the compressed page data
>>> */
>>> struct zswap_entry {
>>> struct rb_node rbnode;
>>> pgoff_t offset;
>>> int refcount;
>>> unsigned int length;
>>> + struct zswap_pool *pool;
>>> unsigned long handle;
>>> };
>>>
>>> @@ -201,6 +156,44 @@ struct zswap_tree {
>>>
>>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>>>
>>> +/* RCU-protected iteration */
>>> +static LIST_HEAD(zswap_pools);
>>> +/* protects zswap_pools list modification */
>>> +static DEFINE_SPINLOCK(zswap_pools_lock);
>>> +
>>> +/*********************************
>>> +* helpers and fwd declarations
>>> +**********************************/
>>> +
>>> +#define zswap_pool_debug(msg, p) \
>>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
>>> + zpool_get_type((p)->zpool))
>>> +
>>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
>>> +static int zswap_pool_get(struct zswap_pool *pool);
>>> +static void zswap_pool_put(struct zswap_pool *pool);
>>> +
>>> +static bool zswap_is_full(void)
>>> +{
>>> + return totalram_pages * zswap_max_pool_percent / 100 <
>>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>> +}
>>> +
>>> +static void zswap_update_total_size(void)
>>> +{
>>> + struct zswap_pool *pool;
>>> + u64 total = 0;
>>> +
>>> + rcu_read_lock();
>>> +
>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>> + total += zpool_get_total_size(pool->zpool);
>>> +
>>> + rcu_read_unlock();
>>> +
>>> + zswap_pool_total_size = total;
>>> +}
>>> +
>>> /*********************************
>>> * zswap entry functions
>>> **********************************/
>>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
>>> */
>>> static void zswap_free_entry(struct zswap_entry *entry)
>>> {
>>> - zpool_free(zswap_pool, entry->handle);
>>> + zpool_free(entry->pool->zpool, entry->handle);
>>> + zswap_pool_put(entry->pool);
>>> zswap_entry_cache_free(entry);
>>> atomic_dec(&zswap_stored_pages);
>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>> + zswap_update_total_size();
>>> }
>>>
>>> /* caller must hold the tree lock */
>>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
>>> **********************************/
>>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>>>
>>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
>>> {
>>> - struct crypto_comp *tfm;
>>> u8 *dst;
>>>
>>> switch (action) {
>>> case CPU_UP_PREPARE:
>>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
>>> - if (IS_ERR(tfm)) {
>>> - pr_err("can't allocate compressor transform\n");
>>> - return NOTIFY_BAD;
>>> - }
>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
>>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
>>> if (!dst) {
>>> pr_err("can't allocate compressor buffer\n");
>>> - crypto_free_comp(tfm);
>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>> return NOTIFY_BAD;
>>> }
>>> per_cpu(zswap_dstmem, cpu) = dst;
>>> break;
>>> case CPU_DEAD:
>>> case CPU_UP_CANCELED:
>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
>>> - if (tfm) {
>>> - crypto_free_comp(tfm);
>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>> - }
>>> dst = per_cpu(zswap_dstmem, cpu);
>>> kfree(dst);
>>> per_cpu(zswap_dstmem, cpu) = NULL;
>>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>> return NOTIFY_OK;
>>> }
>>>
>>> -static int zswap_cpu_notifier(struct notifier_block *nb,
>>> - unsigned long action, void *pcpu)
>>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
>>> + unsigned long action, void *pcpu)
>>> {
>>> - unsigned long cpu = (unsigned long)pcpu;
>>> - return __zswap_cpu_notifier(action, cpu);
>>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
>>> }
>>>
>>> -static struct notifier_block zswap_cpu_notifier_block = {
>>> - .notifier_call = zswap_cpu_notifier
>>> +static struct notifier_block zswap_dstmem_notifier = {
>>> + .notifier_call = zswap_cpu_dstmem_notifier,
>>> };
>>>
>>> -static int __init zswap_cpu_init(void)
>>> +static int __init zswap_cpu_dstmem_init(void)
>>> {
>>> unsigned long cpu;
>>>
>>> cpu_notifier_register_begin();
>>> for_each_online_cpu(cpu)
>>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
>>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
>>> + NOTIFY_BAD)
>>> goto cleanup;
>>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
>>> + __register_cpu_notifier(&zswap_dstmem_notifier);
>>> cpu_notifier_register_done();
>>> return 0;
>>>
>>> cleanup:
>>> for_each_online_cpu(cpu)
>>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>> cpu_notifier_register_done();
>>> return -ENOMEM;
>>> }
>>>
>>> +static void zswap_cpu_dstmem_destroy(void)
>>> +{
>>> + unsigned long cpu;
>>> +
>>> + cpu_notifier_register_begin();
>>> + for_each_online_cpu(cpu)
>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
>>> + cpu_notifier_register_done();
>>> +}
>>> +
>>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
>>> + unsigned long action, unsigned long cpu)
>>> +{
>>> + struct crypto_comp *tfm;
>>> +
>>> + switch (action) {
>>> + case CPU_UP_PREPARE:
>>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
>>> + break;
>>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
>>> + if (IS_ERR_OR_NULL(tfm)) {
>>> + pr_err("could not alloc crypto comp %s : %ld\n",
>>> + pool->tfm_name, PTR_ERR(tfm));
>>> + return NOTIFY_BAD;
>>> + }
>>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
>>> + break;
>>> + case CPU_DEAD:
>>> + case CPU_UP_CANCELED:
>>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
>>> + if (!IS_ERR_OR_NULL(tfm))
>>> + crypto_free_comp(tfm);
>>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
>>> + break;
>>> + default:
>>> + break;
>>> + }
>>> + return NOTIFY_OK;
>>> +}
>>> +
>>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
>>> + unsigned long action, void *pcpu)
>>> +{
>>> + unsigned long cpu = (unsigned long)pcpu;
>>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
>>> +
>>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
>>> +}
>>> +
>>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
>>> +{
>>> + unsigned long cpu;
>>> +
>>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
>>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
>>> +
>>> + cpu_notifier_register_begin();
>>> + for_each_online_cpu(cpu)
>>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
>>> + NOTIFY_BAD)
>>> + goto cleanup;
>>> + __register_cpu_notifier(&pool->notifier);
>>> + cpu_notifier_register_done();
>>> + return 0;
>>> +
>>> +cleanup:
>>> + for_each_online_cpu(cpu)
>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>> + cpu_notifier_register_done();
>>> + return -ENOMEM;
>>> +}
>>> +
>>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
>>> +{
>>> + unsigned long cpu;
>>> +
>>> + cpu_notifier_register_begin();
>>> + for_each_online_cpu(cpu)
>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>> + __unregister_cpu_notifier(&pool->notifier);
>>> + cpu_notifier_register_done();
>>> +}
>>> +
>>> /*********************************
>>> -* helpers
>>> +* pool functions
>>> **********************************/
>>> -static bool zswap_is_full(void)
>>> +
>>> +static struct zswap_pool *__zswap_pool_current(void)
>>> {
>>> - return totalram_pages * zswap_max_pool_percent / 100 <
>>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>> + struct zswap_pool *pool;
>>> +
>>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
>>> + WARN_ON(!pool);
>>> +
>>> + return pool;
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_current(void)
>>> +{
>>> + assert_spin_locked(&zswap_pools_lock);
>>> +
>>> + return __zswap_pool_current();
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_current_get(void)
>>> +{
>>> + struct zswap_pool *pool;
>>> +
>>> + rcu_read_lock();
>>> +
>>> + pool = __zswap_pool_current();
>>> + if (!pool || !zswap_pool_get(pool))
>>> + pool = NULL;
>>> +
>>> + rcu_read_unlock();
>>> +
>>> + return pool;
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_last_get(void)
>>> +{
>>> + struct zswap_pool *pool, *last = NULL;
>>> +
>>> + rcu_read_lock();
>>> +
>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>> + last = pool;
>>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
>>> + last = NULL;
>>> +
>>> + rcu_read_unlock();
>>> +
>>> + return last;
>>> +}
>>> +
>>> +static struct zpool_ops zswap_zpool_ops = {
>>> + .evict = zswap_writeback_entry
>>> +};
>>> +
>>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
>>> +{
>>> + struct zswap_pool *pool;
>>> +
>>> + assert_spin_locked(&zswap_pools_lock);
>>> +
>>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
>>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
>>> + continue;
>>> + if (strncmp(zpool_get_type(pool->zpool), type,
>>> + sizeof(zswap_zpool_type)))
>>> + continue;
>>> + /* if we can't get it, it's about to be destroyed */
>>> + if (!zswap_pool_get(pool))
>>> + continue;
>>> + return pool;
>>> + }
>>> +
>>> + return NULL;
>>> +}
>>> +
>>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
>>> +{
>>> + struct zswap_pool *pool;
>>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>> +
>>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
>>> + if (!pool) {
>>> + pr_err("pool alloc failed\n");
>>> + return NULL;
>>> + }
>>> +
>>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
>>> + if (!pool->zpool) {
>>> + pr_err("%s zpool not available\n", type);
>>> + goto error;
>>> + }
>>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
>>> +
>>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
>>> + pool->tfm = alloc_percpu(struct crypto_comp *);
>>> + if (!pool->tfm) {
>>> + pr_err("percpu alloc failed\n");
>>> + goto error;
>>> + }
>>> +
>>> + if (zswap_cpu_comp_init(pool))
>>> + goto error;
>>> + pr_debug("using %s compressor\n", pool->tfm_name);
>>> +
>>> + /* being the current pool takes 1 ref; this func expects the
>>> + * caller to always add the new pool as the current pool
>>> + */
>>> + kref_init(&pool->kref);
>>> + INIT_LIST_HEAD(&pool->list);
>>> +
>>> + zswap_pool_debug("created", pool);
>>> +
>>> + return pool;
>>> +
>>> +error:
>>> + free_percpu(pool->tfm);
>>> + if (pool->zpool)
>>> + zpool_destroy_pool(pool->zpool);
>>> + kfree(pool);
>>> + return NULL;
>>> +}
>>> +
>>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
>>> +{
>>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>> + pr_err("compressor %s not available, using default %s\n",
>>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
>>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
>>> + sizeof(zswap_compressor));
>>> + }
>>> + if (!zpool_has_pool(zswap_zpool_type)) {
>>> + pr_err("zpool %s not available, using default %s\n",
>>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
>>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
>>> + sizeof(zswap_zpool_type));
>>> + }
>>> +
>>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
>>> +}
>>> +
>>> +static void zswap_pool_destroy(struct zswap_pool *pool)
>>> +{
>>> + zswap_pool_debug("destroying", pool);
>>> +
>>> + zswap_cpu_comp_destroy(pool);
>>> + free_percpu(pool->tfm);
>>> + zpool_destroy_pool(pool->zpool);
>>> + kfree(pool);
>>> +}
>>> +
>>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
>>> +{
>>> + return kref_get_unless_zero(&pool->kref);
>>> +}
>>> +
>>> +static void __zswap_pool_release(struct rcu_head *head)
>>> +{
>>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
>>> +
>>> + /* nobody should have been able to get a kref... */
>>> + WARN_ON(kref_get_unless_zero(&pool->kref));
>>> +
>>> + /* pool is now off zswap_pools list and has no references. */
>>> + zswap_pool_destroy(pool);
>>> +}
>>> +
>>> +static void __zswap_pool_empty(struct kref *kref)
>>> +{
>>> + struct zswap_pool *pool;
>>> +
>>> + pool = container_of(kref, typeof(*pool), kref);
>>> +
>>> + spin_lock(&zswap_pools_lock);
>>> +
>>> + WARN_ON(pool == zswap_pool_current());
>>> +
>>> + list_del_rcu(&pool->list);
>>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
>>> +
>>> + spin_unlock(&zswap_pools_lock);
>>> +}
>>> +
>>> +static void zswap_pool_put(struct zswap_pool *pool)
>>> +{
>>> + kref_put(&pool->kref, __zswap_pool_empty);
>>> +}
>>> +
>>> }
>>>
>>> /*********************************
>>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>> pgoff_t offset;
>>> struct zswap_entry *entry;
>>> struct page *page;
>>> + struct crypto_comp *tfm;
>>> u8 *src, *dst;
>>> unsigned int dlen;
>>> int ret;
>>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
>>> /* decompress */
>>> dlen = PAGE_SIZE;
>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>> dst = kmap_atomic(page);
>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
>>> - entry->length, dst, &dlen);
>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>> + ret = crypto_comp_decompress(tfm, src, entry->length,
>>> + dst, &dlen);
>>> + put_cpu_ptr(entry->pool->tfm);
>>> kunmap_atomic(dst);
>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>> BUG_ON(ret);
>>> BUG_ON(dlen != PAGE_SIZE);
>>>
>>> @@ -633,6 +882,22 @@ end:
>>> return ret;
>>> }
>>>
>>> +static int zswap_shrink(void)
>>> +{
>>> + struct zswap_pool *pool;
>>> + int ret;
>>> +
>>> + pool = zswap_pool_last_get();
>>> + if (!pool)
>>> + return -ENOENT;
>>> +
>>> + ret = zpool_shrink(pool->zpool, 1, NULL);
>>> +
>>> + zswap_pool_put(pool);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> /*********************************
>>> * frontswap hooks
>>> **********************************/
>>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>> {
>>> struct zswap_tree *tree = zswap_trees[type];
>>> struct zswap_entry *entry, *dupentry;
>>> + struct crypto_comp *tfm;
>>> int ret;
>>> unsigned int dlen = PAGE_SIZE, len;
>>> unsigned long handle;
>>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>> /* reclaim space if needed */
>>> if (zswap_is_full()) {
>>> zswap_pool_limit_hit++;
>>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
>>> + if (zswap_shrink()) {
>>> zswap_reject_reclaim_fail++;
>>> ret = -ENOMEM;
>>> goto reject;
>>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>> goto reject;
>>> }
>>>
>>> + /* if entry is successfully added, it keeps the reference */
>>> + entry->pool = zswap_pool_current_get();
>>> + if (!entry->pool) {
>>> + ret = -EINVAL;
>>> + goto freepage;
>>> + }
>>> +
>>> /* compress */
>>> dst = get_cpu_var(zswap_dstmem);
>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>> src = kmap_atomic(page);
>>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
>>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
>>> kunmap_atomic(src);
>>> + put_cpu_ptr(entry->pool->tfm);
>>> if (ret) {
>>> ret = -EINVAL;
>>> - goto freepage;
>>> + goto put_dstmem;
>>> }
>>>
>>> /* store */
>>> len = dlen + sizeof(struct zswap_header);
>>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
>>> - &handle);
>>> + ret = zpool_malloc(entry->pool->zpool, len,
>>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
>>> if (ret == -ENOSPC) {
>>> zswap_reject_compress_poor++;
>>> - goto freepage;
>>> + goto put_dstmem;
>>> }
>>> if (ret) {
>>> zswap_reject_alloc_fail++;
>>> - goto freepage;
>>> + goto put_dstmem;
>>> }
>>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
>>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
>>> zhdr->swpentry = swp_entry(type, offset);
>>> buf = (u8 *)(zhdr + 1);
>>> memcpy(buf, dst, dlen);
>>> - zpool_unmap_handle(zswap_pool, handle);
>>> + zpool_unmap_handle(entry->pool->zpool, handle);
>>> put_cpu_var(zswap_dstmem);
>>>
>>> /* populate entry */
>>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>
>>> /* update stats */
>>> atomic_inc(&zswap_stored_pages);
>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>> + zswap_update_total_size();
>>>
>>> return 0;
>>>
>>> -freepage:
>>> +put_dstmem:
>>> put_cpu_var(zswap_dstmem);
>>> + zswap_pool_put(entry->pool);
>>> +freepage:
>>> zswap_entry_cache_free(entry);
>>> reject:
>>> return ret;
>>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>> {
>>> struct zswap_tree *tree = zswap_trees[type];
>>> struct zswap_entry *entry;
>>> + struct crypto_comp *tfm;
>>> u8 *src, *dst;
>>> unsigned int dlen;
>>> int ret;
>>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>>
>>> /* decompress */
>>> dlen = PAGE_SIZE;
>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>> dst = kmap_atomic(page);
>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
>>> - dst, &dlen);
>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
>>> + put_cpu_ptr(entry->pool->tfm);
>>> kunmap_atomic(dst);
>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>> BUG_ON(ret);
>>>
>>> spin_lock(&tree->lock);
>>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
>>> zswap_trees[type] = NULL;
>>> }
>>>
>>> -static struct zpool_ops zswap_zpool_ops = {
>>> - .evict = zswap_writeback_entry
>>> -};
>>> -
>>> static void zswap_frontswap_init(unsigned type)
>>> {
>>> struct zswap_tree *tree;
>>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
>>> **********************************/
>>> static int __init init_zswap(void)
>>> {
>>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>> + struct zswap_pool *pool;
>>>
>>> - pr_info("loading zswap\n");
>>> -
>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>> - &zswap_zpool_ops);
>>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
>>> - pr_info("%s zpool not available\n", zswap_zpool_type);
>>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>> - &zswap_zpool_ops);
>>> - }
>>> - if (!zswap_pool) {
>>> - pr_err("%s zpool not available\n", zswap_zpool_type);
>>> - pr_err("zpool creation failed\n");
>>> - goto error;
>>> - }
>>> - pr_info("using %s pool\n", zswap_zpool_type);
>>> + pr_info("loading\n");
>>>
>>> if (zswap_entry_cache_create()) {
>>> pr_err("entry cache creation failed\n");
>>> - goto cachefail;
>>> + goto cache_fail;
>>> }
>>> - if (zswap_comp_init()) {
>>> - pr_err("compressor initialization failed\n");
>>> - goto compfail;
>>> +
>>> + if (zswap_cpu_dstmem_init()) {
>>> + pr_err("dstmem alloc failed\n");
>>> + goto dstmem_fail;
>>> }
>>> - if (zswap_cpu_init()) {
>>> - pr_err("per-cpu initialization failed\n");
>>> - goto pcpufail;
>>> +
>>> + pool = __zswap_pool_create_fallback();
>>> + if (!pool) {
>>> + pr_err("pool creation failed\n");
>>> + goto pool_fail;
>>> }
>>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
>>> + zpool_get_type(pool->zpool));
>>> +
>>> + list_add(&pool->list, &zswap_pools);
>>>
>>> frontswap_register_ops(&zswap_frontswap_ops);
>>> if (zswap_debugfs_init())
>>> pr_warn("debugfs initialization failed\n");
>>> return 0;
>>> -pcpufail:
>>> - zswap_comp_exit();
>>> -compfail:
>>> +
>>> +pool_fail:
>>> + zswap_cpu_dstmem_destroy();
>>> +dstmem_fail:
>>> zswap_entry_cache_destroy();
>>> -cachefail:
>>> - zpool_destroy_pool(zswap_pool);
>>> -error:
>>> +cache_fail:
>>> return -ENOMEM;
>>> }
>>> /* must be late so crypto has time to come up */
>>> --
>>> 2.1.0
>>>
--
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-17 23:13 ` Dan Streetman
@ 2015-06-18 15:21 ` Seth Jennings
-1 siblings, 0 replies; 22+ messages in thread
From: Seth Jennings @ 2015-06-18 15:21 UTC (permalink / raw)
To: Dan Streetman; +Cc: Andrew Morton, Linux-MM, linux-kernel
On Wed, Jun 17, 2015 at 07:13:31PM -0400, Dan Streetman wrote:
> On Wed, Jun 10, 2015 at 4:54 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> > On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> >> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> >>> Add dynamic creation of pools. Move the static crypto compression
> >>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> >>> the pool it's in.
> >>
> >> Seth, as far as the design, from your previous comments I assume you
> >> were thinking of maintaining separate lists of zpools and compressors?
> >> I do see how that will reduce duplication of zpools and compressors,
> >> but it also requires adding a new pointer to each zswap_entry, and
> >> increasing the amount of code to manage each list separately. And the
> >> most common case in zswap will be just a single zpool and compressor,
> >> not repeatedly changing params. What do you think?
> >
> > Any opinion on this patch? If you want, I can break it up so there's
> > a list of zpools and a list of compressors. Either the combined way
> > (this patch) or separate lists works for me, as long as the params are
> > changeable at runtime :-)
>
> You on vacation Seth? Let me know what direction you prefer for this...
I think it is as good as it can be. Complicated, but I don't know of a
way to make it less so if we want to be able to do this (which is a
separate discussion).
Seth
>
> >
> >
> >>
> >>>
> >>> This is required by a separate patch which enables changing the
> >>> zswap zpool and compressor params at runtime.
> >>>
> >>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> >>> ---
> >>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> >>> 1 file changed, 408 insertions(+), 142 deletions(-)
> >>>
> >>> diff --git a/mm/zswap.c b/mm/zswap.c
> >>> index 2d5727b..fc93770 100644
> >>> --- a/mm/zswap.c
> >>> +++ b/mm/zswap.c
> >>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> >>> static struct zpool *zswap_pool;
> >>>
> >>> /*********************************
> >>> -* compression functions
> >>> +* data structures
> >>> **********************************/
> >>> -/* per-cpu compression transforms */
> >>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> >>>
> >>> -enum comp_op {
> >>> - ZSWAP_COMPOP_COMPRESS,
> >>> - ZSWAP_COMPOP_DECOMPRESS
> >>> +struct zswap_pool {
> >>> + struct zpool *zpool;
> >>> + struct kref kref;
> >>> + struct list_head list;
> >>> + struct rcu_head rcu_head;
> >>> + struct notifier_block notifier;
> >>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> >>> + struct crypto_comp * __percpu *tfm;
> >>> };
> >>>
> >>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> >>> - u8 *dst, unsigned int *dlen)
> >>> -{
> >>> - struct crypto_comp *tfm;
> >>> - int ret;
> >>> -
> >>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> >>> - switch (op) {
> >>> - case ZSWAP_COMPOP_COMPRESS:
> >>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> >>> - break;
> >>> - case ZSWAP_COMPOP_DECOMPRESS:
> >>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> >>> - break;
> >>> - default:
> >>> - ret = -EINVAL;
> >>> - }
> >>> -
> >>> - put_cpu();
> >>> - return ret;
> >>> -}
> >>> -
> >>> -static int __init zswap_comp_init(void)
> >>> -{
> >>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >>> - pr_info("%s compressor not available\n", zswap_compressor);
> >>> - /* fall back to default compressor */
> >>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> >>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> >>> - /* can't even load the default compressor */
> >>> - return -ENODEV;
> >>> - }
> >>> - pr_info("using %s compressor\n", zswap_compressor);
> >>> -
> >>> - /* alloc percpu transforms */
> >>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> >>> - if (!zswap_comp_pcpu_tfms)
> >>> - return -ENOMEM;
> >>> - return 0;
> >>> -}
> >>> -
> >>> -static void __init zswap_comp_exit(void)
> >>> -{
> >>> - /* free percpu transforms */
> >>> - free_percpu(zswap_comp_pcpu_tfms);
> >>> -}
> >>> -
> >>> -/*********************************
> >>> -* data structures
> >>> -**********************************/
> >>> /*
> >>> * struct zswap_entry
> >>> *
> >>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> >>> * page within zswap.
> >>> *
> >>> * rbnode - links the entry into red-black tree for the appropriate swap type
> >>> + * offset - the swap offset for the entry. Index into the red-black tree.
> >>> * refcount - the number of outstanding reference to the entry. This is needed
> >>> * to protect against premature freeing of the entry by code
> >>> * concurrent calls to load, invalidate, and writeback. The lock
> >>> * for the zswap_tree structure that contains the entry must
> >>> * be held while changing the refcount. Since the lock must
> >>> * be held, there is no reason to also make refcount atomic.
> >>> - * offset - the swap offset for the entry. Index into the red-black tree.
> >>> - * handle - zpool allocation handle that stores the compressed page data
> >>> * length - the length in bytes of the compressed page data. Needed during
> >>> * decompression
> >>> + * pool - the zswap_pool the entry's data is in
> >>> + * handle - zpool allocation handle that stores the compressed page data
> >>> */
> >>> struct zswap_entry {
> >>> struct rb_node rbnode;
> >>> pgoff_t offset;
> >>> int refcount;
> >>> unsigned int length;
> >>> + struct zswap_pool *pool;
> >>> unsigned long handle;
> >>> };
> >>>
> >>> @@ -201,6 +156,44 @@ struct zswap_tree {
> >>>
> >>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> >>>
> >>> +/* RCU-protected iteration */
> >>> +static LIST_HEAD(zswap_pools);
> >>> +/* protects zswap_pools list modification */
> >>> +static DEFINE_SPINLOCK(zswap_pools_lock);
> >>> +
> >>> +/*********************************
> >>> +* helpers and fwd declarations
> >>> +**********************************/
> >>> +
> >>> +#define zswap_pool_debug(msg, p) \
> >>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> >>> + zpool_get_type((p)->zpool))
> >>> +
> >>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> >>> +static int zswap_pool_get(struct zswap_pool *pool);
> >>> +static void zswap_pool_put(struct zswap_pool *pool);
> >>> +
> >>> +static bool zswap_is_full(void)
> >>> +{
> >>> + return totalram_pages * zswap_max_pool_percent / 100 <
> >>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >>> +}
> >>> +
> >>> +static void zswap_update_total_size(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + u64 total = 0;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >>> + total += zpool_get_total_size(pool->zpool);
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + zswap_pool_total_size = total;
> >>> +}
> >>> +
> >>> /*********************************
> >>> * zswap entry functions
> >>> **********************************/
> >>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> >>> */
> >>> static void zswap_free_entry(struct zswap_entry *entry)
> >>> {
> >>> - zpool_free(zswap_pool, entry->handle);
> >>> + zpool_free(entry->pool->zpool, entry->handle);
> >>> + zswap_pool_put(entry->pool);
> >>> zswap_entry_cache_free(entry);
> >>> atomic_dec(&zswap_stored_pages);
> >>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >>> + zswap_update_total_size();
> >>> }
> >>>
> >>> /* caller must hold the tree lock */
> >>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> >>> **********************************/
> >>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> >>>
> >>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> >>> {
> >>> - struct crypto_comp *tfm;
> >>> u8 *dst;
> >>>
> >>> switch (action) {
> >>> case CPU_UP_PREPARE:
> >>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> >>> - if (IS_ERR(tfm)) {
> >>> - pr_err("can't allocate compressor transform\n");
> >>> - return NOTIFY_BAD;
> >>> - }
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> >>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> >>> if (!dst) {
> >>> pr_err("can't allocate compressor buffer\n");
> >>> - crypto_free_comp(tfm);
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >>> return NOTIFY_BAD;
> >>> }
> >>> per_cpu(zswap_dstmem, cpu) = dst;
> >>> break;
> >>> case CPU_DEAD:
> >>> case CPU_UP_CANCELED:
> >>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> >>> - if (tfm) {
> >>> - crypto_free_comp(tfm);
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >>> - }
> >>> dst = per_cpu(zswap_dstmem, cpu);
> >>> kfree(dst);
> >>> per_cpu(zswap_dstmem, cpu) = NULL;
> >>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >>> return NOTIFY_OK;
> >>> }
> >>>
> >>> -static int zswap_cpu_notifier(struct notifier_block *nb,
> >>> - unsigned long action, void *pcpu)
> >>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> >>> + unsigned long action, void *pcpu)
> >>> {
> >>> - unsigned long cpu = (unsigned long)pcpu;
> >>> - return __zswap_cpu_notifier(action, cpu);
> >>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> >>> }
> >>>
> >>> -static struct notifier_block zswap_cpu_notifier_block = {
> >>> - .notifier_call = zswap_cpu_notifier
> >>> +static struct notifier_block zswap_dstmem_notifier = {
> >>> + .notifier_call = zswap_cpu_dstmem_notifier,
> >>> };
> >>>
> >>> -static int __init zswap_cpu_init(void)
> >>> +static int __init zswap_cpu_dstmem_init(void)
> >>> {
> >>> unsigned long cpu;
> >>>
> >>> cpu_notifier_register_begin();
> >>> for_each_online_cpu(cpu)
> >>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> >>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> >>> + NOTIFY_BAD)
> >>> goto cleanup;
> >>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> >>> + __register_cpu_notifier(&zswap_dstmem_notifier);
> >>> cpu_notifier_register_done();
> >>> return 0;
> >>>
> >>> cleanup:
> >>> for_each_online_cpu(cpu)
> >>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> >>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >>> cpu_notifier_register_done();
> >>> return -ENOMEM;
> >>> }
> >>>
> >>> +static void zswap_cpu_dstmem_destroy(void)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> >>> + cpu_notifier_register_done();
> >>> +}
> >>> +
> >>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> >>> + unsigned long action, unsigned long cpu)
> >>> +{
> >>> + struct crypto_comp *tfm;
> >>> +
> >>> + switch (action) {
> >>> + case CPU_UP_PREPARE:
> >>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> >>> + break;
> >>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> >>> + if (IS_ERR_OR_NULL(tfm)) {
> >>> + pr_err("could not alloc crypto comp %s : %ld\n",
> >>> + pool->tfm_name, PTR_ERR(tfm));
> >>> + return NOTIFY_BAD;
> >>> + }
> >>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> >>> + break;
> >>> + case CPU_DEAD:
> >>> + case CPU_UP_CANCELED:
> >>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> >>> + if (!IS_ERR_OR_NULL(tfm))
> >>> + crypto_free_comp(tfm);
> >>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> >>> + break;
> >>> + default:
> >>> + break;
> >>> + }
> >>> + return NOTIFY_OK;
> >>> +}
> >>> +
> >>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> >>> + unsigned long action, void *pcpu)
> >>> +{
> >>> + unsigned long cpu = (unsigned long)pcpu;
> >>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> >>> +
> >>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> >>> +}
> >>> +
> >>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> >>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> >>> + NOTIFY_BAD)
> >>> + goto cleanup;
> >>> + __register_cpu_notifier(&pool->notifier);
> >>> + cpu_notifier_register_done();
> >>> + return 0;
> >>> +
> >>> +cleanup:
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >>> + cpu_notifier_register_done();
> >>> + return -ENOMEM;
> >>> +}
> >>> +
> >>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >>> + __unregister_cpu_notifier(&pool->notifier);
> >>> + cpu_notifier_register_done();
> >>> +}
> >>> +
> >>> /*********************************
> >>> -* helpers
> >>> +* pool functions
> >>> **********************************/
> >>> -static bool zswap_is_full(void)
> >>> +
> >>> +static struct zswap_pool *__zswap_pool_current(void)
> >>> {
> >>> - return totalram_pages * zswap_max_pool_percent / 100 <
> >>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> >>> + WARN_ON(!pool);
> >>> +
> >>> + return pool;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_current(void)
> >>> +{
> >>> + assert_spin_locked(&zswap_pools_lock);
> >>> +
> >>> + return __zswap_pool_current();
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_current_get(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + pool = __zswap_pool_current();
> >>> + if (!pool || !zswap_pool_get(pool))
> >>> + pool = NULL;
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + return pool;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_last_get(void)
> >>> +{
> >>> + struct zswap_pool *pool, *last = NULL;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >>> + last = pool;
> >>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> >>> + last = NULL;
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + return last;
> >>> +}
> >>> +
> >>> +static struct zpool_ops zswap_zpool_ops = {
> >>> + .evict = zswap_writeback_entry
> >>> +};
> >>> +
> >>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + assert_spin_locked(&zswap_pools_lock);
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> >>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> >>> + continue;
> >>> + if (strncmp(zpool_get_type(pool->zpool), type,
> >>> + sizeof(zswap_zpool_type)))
> >>> + continue;
> >>> + /* if we can't get it, it's about to be destroyed */
> >>> + if (!zswap_pool_get(pool))
> >>> + continue;
> >>> + return pool;
> >>> + }
> >>> +
> >>> + return NULL;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >>> +
> >>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> >>> + if (!pool) {
> >>> + pr_err("pool alloc failed\n");
> >>> + return NULL;
> >>> + }
> >>> +
> >>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> >>> + if (!pool->zpool) {
> >>> + pr_err("%s zpool not available\n", type);
> >>> + goto error;
> >>> + }
> >>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> >>> +
> >>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> >>> + pool->tfm = alloc_percpu(struct crypto_comp *);
> >>> + if (!pool->tfm) {
> >>> + pr_err("percpu alloc failed\n");
> >>> + goto error;
> >>> + }
> >>> +
> >>> + if (zswap_cpu_comp_init(pool))
> >>> + goto error;
> >>> + pr_debug("using %s compressor\n", pool->tfm_name);
> >>> +
> >>> + /* being the current pool takes 1 ref; this func expects the
> >>> + * caller to always add the new pool as the current pool
> >>> + */
> >>> + kref_init(&pool->kref);
> >>> + INIT_LIST_HEAD(&pool->list);
> >>> +
> >>> + zswap_pool_debug("created", pool);
> >>> +
> >>> + return pool;
> >>> +
> >>> +error:
> >>> + free_percpu(pool->tfm);
> >>> + if (pool->zpool)
> >>> + zpool_destroy_pool(pool->zpool);
> >>> + kfree(pool);
> >>> + return NULL;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> >>> +{
> >>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >>> + pr_err("compressor %s not available, using default %s\n",
> >>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> >>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> >>> + sizeof(zswap_compressor));
> >>> + }
> >>> + if (!zpool_has_pool(zswap_zpool_type)) {
> >>> + pr_err("zpool %s not available, using default %s\n",
> >>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> >>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> >>> + sizeof(zswap_zpool_type));
> >>> + }
> >>> +
> >>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> >>> +}
> >>> +
> >>> +static void zswap_pool_destroy(struct zswap_pool *pool)
> >>> +{
> >>> + zswap_pool_debug("destroying", pool);
> >>> +
> >>> + zswap_cpu_comp_destroy(pool);
> >>> + free_percpu(pool->tfm);
> >>> + zpool_destroy_pool(pool->zpool);
> >>> + kfree(pool);
> >>> +}
> >>> +
> >>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> >>> +{
> >>> + return kref_get_unless_zero(&pool->kref);
> >>> +}
> >>> +
> >>> +static void __zswap_pool_release(struct rcu_head *head)
> >>> +{
> >>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> >>> +
> >>> + /* nobody should have been able to get a kref... */
> >>> + WARN_ON(kref_get_unless_zero(&pool->kref));
> >>> +
> >>> + /* pool is now off zswap_pools list and has no references. */
> >>> + zswap_pool_destroy(pool);
> >>> +}
> >>> +
> >>> +static void __zswap_pool_empty(struct kref *kref)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + pool = container_of(kref, typeof(*pool), kref);
> >>> +
> >>> + spin_lock(&zswap_pools_lock);
> >>> +
> >>> + WARN_ON(pool == zswap_pool_current());
> >>> +
> >>> + list_del_rcu(&pool->list);
> >>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> >>> +
> >>> + spin_unlock(&zswap_pools_lock);
> >>> +}
> >>> +
> >>> +static void zswap_pool_put(struct zswap_pool *pool)
> >>> +{
> >>> + kref_put(&pool->kref, __zswap_pool_empty);
> >>> +}
> >>> +
> >>> }
> >>>
> >>> /*********************************
> >>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >>> pgoff_t offset;
> >>> struct zswap_entry *entry;
> >>> struct page *page;
> >>> + struct crypto_comp *tfm;
> >>> u8 *src, *dst;
> >>> unsigned int dlen;
> >>> int ret;
> >>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> >>> /* decompress */
> >>> dlen = PAGE_SIZE;
> >>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >>> dst = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> >>> - entry->length, dst, &dlen);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> + ret = crypto_comp_decompress(tfm, src, entry->length,
> >>> + dst, &dlen);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> kunmap_atomic(dst);
> >>> - zpool_unmap_handle(zswap_pool, entry->handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >>> BUG_ON(ret);
> >>> BUG_ON(dlen != PAGE_SIZE);
> >>>
> >>> @@ -633,6 +882,22 @@ end:
> >>> return ret;
> >>> }
> >>>
> >>> +static int zswap_shrink(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + int ret;
> >>> +
> >>> + pool = zswap_pool_last_get();
> >>> + if (!pool)
> >>> + return -ENOENT;
> >>> +
> >>> + ret = zpool_shrink(pool->zpool, 1, NULL);
> >>> +
> >>> + zswap_pool_put(pool);
> >>> +
> >>> + return ret;
> >>> +}
> >>> +
> >>> /*********************************
> >>> * frontswap hooks
> >>> **********************************/
> >>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> {
> >>> struct zswap_tree *tree = zswap_trees[type];
> >>> struct zswap_entry *entry, *dupentry;
> >>> + struct crypto_comp *tfm;
> >>> int ret;
> >>> unsigned int dlen = PAGE_SIZE, len;
> >>> unsigned long handle;
> >>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> /* reclaim space if needed */
> >>> if (zswap_is_full()) {
> >>> zswap_pool_limit_hit++;
> >>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> >>> + if (zswap_shrink()) {
> >>> zswap_reject_reclaim_fail++;
> >>> ret = -ENOMEM;
> >>> goto reject;
> >>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> goto reject;
> >>> }
> >>>
> >>> + /* if entry is successfully added, it keeps the reference */
> >>> + entry->pool = zswap_pool_current_get();
> >>> + if (!entry->pool) {
> >>> + ret = -EINVAL;
> >>> + goto freepage;
> >>> + }
> >>> +
> >>> /* compress */
> >>> dst = get_cpu_var(zswap_dstmem);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> src = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> >>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> >>> kunmap_atomic(src);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> if (ret) {
> >>> ret = -EINVAL;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>>
> >>> /* store */
> >>> len = dlen + sizeof(struct zswap_header);
> >>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> >>> - &handle);
> >>> + ret = zpool_malloc(entry->pool->zpool, len,
> >>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> >>> if (ret == -ENOSPC) {
> >>> zswap_reject_compress_poor++;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>> if (ret) {
> >>> zswap_reject_alloc_fail++;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> >>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> >>> zhdr->swpentry = swp_entry(type, offset);
> >>> buf = (u8 *)(zhdr + 1);
> >>> memcpy(buf, dst, dlen);
> >>> - zpool_unmap_handle(zswap_pool, handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, handle);
> >>> put_cpu_var(zswap_dstmem);
> >>>
> >>> /* populate entry */
> >>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>>
> >>> /* update stats */
> >>> atomic_inc(&zswap_stored_pages);
> >>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >>> + zswap_update_total_size();
> >>>
> >>> return 0;
> >>>
> >>> -freepage:
> >>> +put_dstmem:
> >>> put_cpu_var(zswap_dstmem);
> >>> + zswap_pool_put(entry->pool);
> >>> +freepage:
> >>> zswap_entry_cache_free(entry);
> >>> reject:
> >>> return ret;
> >>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>> {
> >>> struct zswap_tree *tree = zswap_trees[type];
> >>> struct zswap_entry *entry;
> >>> + struct crypto_comp *tfm;
> >>> u8 *src, *dst;
> >>> unsigned int dlen;
> >>> int ret;
> >>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>>
> >>> /* decompress */
> >>> dlen = PAGE_SIZE;
> >>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >>> dst = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> >>> - dst, &dlen);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> kunmap_atomic(dst);
> >>> - zpool_unmap_handle(zswap_pool, entry->handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >>> BUG_ON(ret);
> >>>
> >>> spin_lock(&tree->lock);
> >>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> >>> zswap_trees[type] = NULL;
> >>> }
> >>>
> >>> -static struct zpool_ops zswap_zpool_ops = {
> >>> - .evict = zswap_writeback_entry
> >>> -};
> >>> -
> >>> static void zswap_frontswap_init(unsigned type)
> >>> {
> >>> struct zswap_tree *tree;
> >>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> >>> **********************************/
> >>> static int __init init_zswap(void)
> >>> {
> >>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >>> + struct zswap_pool *pool;
> >>>
> >>> - pr_info("loading zswap\n");
> >>> -
> >>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >>> - &zswap_zpool_ops);
> >>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> >>> - pr_info("%s zpool not available\n", zswap_zpool_type);
> >>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> >>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >>> - &zswap_zpool_ops);
> >>> - }
> >>> - if (!zswap_pool) {
> >>> - pr_err("%s zpool not available\n", zswap_zpool_type);
> >>> - pr_err("zpool creation failed\n");
> >>> - goto error;
> >>> - }
> >>> - pr_info("using %s pool\n", zswap_zpool_type);
> >>> + pr_info("loading\n");
> >>>
> >>> if (zswap_entry_cache_create()) {
> >>> pr_err("entry cache creation failed\n");
> >>> - goto cachefail;
> >>> + goto cache_fail;
> >>> }
> >>> - if (zswap_comp_init()) {
> >>> - pr_err("compressor initialization failed\n");
> >>> - goto compfail;
> >>> +
> >>> + if (zswap_cpu_dstmem_init()) {
> >>> + pr_err("dstmem alloc failed\n");
> >>> + goto dstmem_fail;
> >>> }
> >>> - if (zswap_cpu_init()) {
> >>> - pr_err("per-cpu initialization failed\n");
> >>> - goto pcpufail;
> >>> +
> >>> + pool = __zswap_pool_create_fallback();
> >>> + if (!pool) {
> >>> + pr_err("pool creation failed\n");
> >>> + goto pool_fail;
> >>> }
> >>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> >>> + zpool_get_type(pool->zpool));
> >>> +
> >>> + list_add(&pool->list, &zswap_pools);
> >>>
> >>> frontswap_register_ops(&zswap_frontswap_ops);
> >>> if (zswap_debugfs_init())
> >>> pr_warn("debugfs initialization failed\n");
> >>> return 0;
> >>> -pcpufail:
> >>> - zswap_comp_exit();
> >>> -compfail:
> >>> +
> >>> +pool_fail:
> >>> + zswap_cpu_dstmem_destroy();
> >>> +dstmem_fail:
> >>> zswap_entry_cache_destroy();
> >>> -cachefail:
> >>> - zpool_destroy_pool(zswap_pool);
> >>> -error:
> >>> +cache_fail:
> >>> return -ENOMEM;
> >>> }
> >>> /* must be late so crypto has time to come up */
> >>> --
> >>> 2.1.0
> >>>
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-18 15:21 ` Seth Jennings
0 siblings, 0 replies; 22+ messages in thread
From: Seth Jennings @ 2015-06-18 15:21 UTC (permalink / raw)
To: Dan Streetman; +Cc: Andrew Morton, Linux-MM, linux-kernel
On Wed, Jun 17, 2015 at 07:13:31PM -0400, Dan Streetman wrote:
> On Wed, Jun 10, 2015 at 4:54 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> > On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> >> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> >>> Add dynamic creation of pools. Move the static crypto compression
> >>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> >>> the pool it's in.
> >>
> >> Seth, as far as the design, from your previous comments I assume you
> >> were thinking of maintaining separate lists of zpools and compressors?
> >> I do see how that will reduce duplication of zpools and compressors,
> >> but it also requires adding a new pointer to each zswap_entry, and
> >> increasing the amount of code to manage each list separately. And the
> >> most common case in zswap will be just a single zpool and compressor,
> >> not repeatedly changing params. What do you think?
> >
> > Any opinion on this patch? If you want, I can break it up so there's
> > a list of zpools and a list of compressors. Either the combined way
> > (this patch) or separate lists works for me, as long as the params are
> > changeable at runtime :-)
>
> You on vacation Seth? Let me know what direction you prefer for this...
I think it is as good as it can be. Complicated, but I don't know of a
way to make it less so if we want to be able to do this (which is a
separate discussion).
Seth
>
> >
> >
> >>
> >>>
> >>> This is required by a separate patch which enables changing the
> >>> zswap zpool and compressor params at runtime.
> >>>
> >>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> >>> ---
> >>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> >>> 1 file changed, 408 insertions(+), 142 deletions(-)
> >>>
> >>> diff --git a/mm/zswap.c b/mm/zswap.c
> >>> index 2d5727b..fc93770 100644
> >>> --- a/mm/zswap.c
> >>> +++ b/mm/zswap.c
> >>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> >>> static struct zpool *zswap_pool;
> >>>
> >>> /*********************************
> >>> -* compression functions
> >>> +* data structures
> >>> **********************************/
> >>> -/* per-cpu compression transforms */
> >>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> >>>
> >>> -enum comp_op {
> >>> - ZSWAP_COMPOP_COMPRESS,
> >>> - ZSWAP_COMPOP_DECOMPRESS
> >>> +struct zswap_pool {
> >>> + struct zpool *zpool;
> >>> + struct kref kref;
> >>> + struct list_head list;
> >>> + struct rcu_head rcu_head;
> >>> + struct notifier_block notifier;
> >>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> >>> + struct crypto_comp * __percpu *tfm;
> >>> };
> >>>
> >>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> >>> - u8 *dst, unsigned int *dlen)
> >>> -{
> >>> - struct crypto_comp *tfm;
> >>> - int ret;
> >>> -
> >>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> >>> - switch (op) {
> >>> - case ZSWAP_COMPOP_COMPRESS:
> >>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> >>> - break;
> >>> - case ZSWAP_COMPOP_DECOMPRESS:
> >>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> >>> - break;
> >>> - default:
> >>> - ret = -EINVAL;
> >>> - }
> >>> -
> >>> - put_cpu();
> >>> - return ret;
> >>> -}
> >>> -
> >>> -static int __init zswap_comp_init(void)
> >>> -{
> >>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >>> - pr_info("%s compressor not available\n", zswap_compressor);
> >>> - /* fall back to default compressor */
> >>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> >>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> >>> - /* can't even load the default compressor */
> >>> - return -ENODEV;
> >>> - }
> >>> - pr_info("using %s compressor\n", zswap_compressor);
> >>> -
> >>> - /* alloc percpu transforms */
> >>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> >>> - if (!zswap_comp_pcpu_tfms)
> >>> - return -ENOMEM;
> >>> - return 0;
> >>> -}
> >>> -
> >>> -static void __init zswap_comp_exit(void)
> >>> -{
> >>> - /* free percpu transforms */
> >>> - free_percpu(zswap_comp_pcpu_tfms);
> >>> -}
> >>> -
> >>> -/*********************************
> >>> -* data structures
> >>> -**********************************/
> >>> /*
> >>> * struct zswap_entry
> >>> *
> >>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> >>> * page within zswap.
> >>> *
> >>> * rbnode - links the entry into red-black tree for the appropriate swap type
> >>> + * offset - the swap offset for the entry. Index into the red-black tree.
> >>> * refcount - the number of outstanding reference to the entry. This is needed
> >>> * to protect against premature freeing of the entry by code
> >>> * concurrent calls to load, invalidate, and writeback. The lock
> >>> * for the zswap_tree structure that contains the entry must
> >>> * be held while changing the refcount. Since the lock must
> >>> * be held, there is no reason to also make refcount atomic.
> >>> - * offset - the swap offset for the entry. Index into the red-black tree.
> >>> - * handle - zpool allocation handle that stores the compressed page data
> >>> * length - the length in bytes of the compressed page data. Needed during
> >>> * decompression
> >>> + * pool - the zswap_pool the entry's data is in
> >>> + * handle - zpool allocation handle that stores the compressed page data
> >>> */
> >>> struct zswap_entry {
> >>> struct rb_node rbnode;
> >>> pgoff_t offset;
> >>> int refcount;
> >>> unsigned int length;
> >>> + struct zswap_pool *pool;
> >>> unsigned long handle;
> >>> };
> >>>
> >>> @@ -201,6 +156,44 @@ struct zswap_tree {
> >>>
> >>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> >>>
> >>> +/* RCU-protected iteration */
> >>> +static LIST_HEAD(zswap_pools);
> >>> +/* protects zswap_pools list modification */
> >>> +static DEFINE_SPINLOCK(zswap_pools_lock);
> >>> +
> >>> +/*********************************
> >>> +* helpers and fwd declarations
> >>> +**********************************/
> >>> +
> >>> +#define zswap_pool_debug(msg, p) \
> >>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> >>> + zpool_get_type((p)->zpool))
> >>> +
> >>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> >>> +static int zswap_pool_get(struct zswap_pool *pool);
> >>> +static void zswap_pool_put(struct zswap_pool *pool);
> >>> +
> >>> +static bool zswap_is_full(void)
> >>> +{
> >>> + return totalram_pages * zswap_max_pool_percent / 100 <
> >>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >>> +}
> >>> +
> >>> +static void zswap_update_total_size(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + u64 total = 0;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >>> + total += zpool_get_total_size(pool->zpool);
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + zswap_pool_total_size = total;
> >>> +}
> >>> +
> >>> /*********************************
> >>> * zswap entry functions
> >>> **********************************/
> >>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> >>> */
> >>> static void zswap_free_entry(struct zswap_entry *entry)
> >>> {
> >>> - zpool_free(zswap_pool, entry->handle);
> >>> + zpool_free(entry->pool->zpool, entry->handle);
> >>> + zswap_pool_put(entry->pool);
> >>> zswap_entry_cache_free(entry);
> >>> atomic_dec(&zswap_stored_pages);
> >>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >>> + zswap_update_total_size();
> >>> }
> >>>
> >>> /* caller must hold the tree lock */
> >>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> >>> **********************************/
> >>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> >>>
> >>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> >>> {
> >>> - struct crypto_comp *tfm;
> >>> u8 *dst;
> >>>
> >>> switch (action) {
> >>> case CPU_UP_PREPARE:
> >>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> >>> - if (IS_ERR(tfm)) {
> >>> - pr_err("can't allocate compressor transform\n");
> >>> - return NOTIFY_BAD;
> >>> - }
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> >>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> >>> if (!dst) {
> >>> pr_err("can't allocate compressor buffer\n");
> >>> - crypto_free_comp(tfm);
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >>> return NOTIFY_BAD;
> >>> }
> >>> per_cpu(zswap_dstmem, cpu) = dst;
> >>> break;
> >>> case CPU_DEAD:
> >>> case CPU_UP_CANCELED:
> >>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> >>> - if (tfm) {
> >>> - crypto_free_comp(tfm);
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >>> - }
> >>> dst = per_cpu(zswap_dstmem, cpu);
> >>> kfree(dst);
> >>> per_cpu(zswap_dstmem, cpu) = NULL;
> >>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >>> return NOTIFY_OK;
> >>> }
> >>>
> >>> -static int zswap_cpu_notifier(struct notifier_block *nb,
> >>> - unsigned long action, void *pcpu)
> >>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> >>> + unsigned long action, void *pcpu)
> >>> {
> >>> - unsigned long cpu = (unsigned long)pcpu;
> >>> - return __zswap_cpu_notifier(action, cpu);
> >>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> >>> }
> >>>
> >>> -static struct notifier_block zswap_cpu_notifier_block = {
> >>> - .notifier_call = zswap_cpu_notifier
> >>> +static struct notifier_block zswap_dstmem_notifier = {
> >>> + .notifier_call = zswap_cpu_dstmem_notifier,
> >>> };
> >>>
> >>> -static int __init zswap_cpu_init(void)
> >>> +static int __init zswap_cpu_dstmem_init(void)
> >>> {
> >>> unsigned long cpu;
> >>>
> >>> cpu_notifier_register_begin();
> >>> for_each_online_cpu(cpu)
> >>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> >>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> >>> + NOTIFY_BAD)
> >>> goto cleanup;
> >>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> >>> + __register_cpu_notifier(&zswap_dstmem_notifier);
> >>> cpu_notifier_register_done();
> >>> return 0;
> >>>
> >>> cleanup:
> >>> for_each_online_cpu(cpu)
> >>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> >>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >>> cpu_notifier_register_done();
> >>> return -ENOMEM;
> >>> }
> >>>
> >>> +static void zswap_cpu_dstmem_destroy(void)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> >>> + cpu_notifier_register_done();
> >>> +}
> >>> +
> >>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> >>> + unsigned long action, unsigned long cpu)
> >>> +{
> >>> + struct crypto_comp *tfm;
> >>> +
> >>> + switch (action) {
> >>> + case CPU_UP_PREPARE:
> >>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> >>> + break;
> >>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> >>> + if (IS_ERR_OR_NULL(tfm)) {
> >>> + pr_err("could not alloc crypto comp %s : %ld\n",
> >>> + pool->tfm_name, PTR_ERR(tfm));
> >>> + return NOTIFY_BAD;
> >>> + }
> >>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> >>> + break;
> >>> + case CPU_DEAD:
> >>> + case CPU_UP_CANCELED:
> >>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> >>> + if (!IS_ERR_OR_NULL(tfm))
> >>> + crypto_free_comp(tfm);
> >>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> >>> + break;
> >>> + default:
> >>> + break;
> >>> + }
> >>> + return NOTIFY_OK;
> >>> +}
> >>> +
> >>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> >>> + unsigned long action, void *pcpu)
> >>> +{
> >>> + unsigned long cpu = (unsigned long)pcpu;
> >>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> >>> +
> >>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> >>> +}
> >>> +
> >>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> >>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> >>> + NOTIFY_BAD)
> >>> + goto cleanup;
> >>> + __register_cpu_notifier(&pool->notifier);
> >>> + cpu_notifier_register_done();
> >>> + return 0;
> >>> +
> >>> +cleanup:
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >>> + cpu_notifier_register_done();
> >>> + return -ENOMEM;
> >>> +}
> >>> +
> >>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >>> + __unregister_cpu_notifier(&pool->notifier);
> >>> + cpu_notifier_register_done();
> >>> +}
> >>> +
> >>> /*********************************
> >>> -* helpers
> >>> +* pool functions
> >>> **********************************/
> >>> -static bool zswap_is_full(void)
> >>> +
> >>> +static struct zswap_pool *__zswap_pool_current(void)
> >>> {
> >>> - return totalram_pages * zswap_max_pool_percent / 100 <
> >>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> >>> + WARN_ON(!pool);
> >>> +
> >>> + return pool;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_current(void)
> >>> +{
> >>> + assert_spin_locked(&zswap_pools_lock);
> >>> +
> >>> + return __zswap_pool_current();
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_current_get(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + pool = __zswap_pool_current();
> >>> + if (!pool || !zswap_pool_get(pool))
> >>> + pool = NULL;
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + return pool;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_last_get(void)
> >>> +{
> >>> + struct zswap_pool *pool, *last = NULL;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >>> + last = pool;
> >>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> >>> + last = NULL;
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + return last;
> >>> +}
> >>> +
> >>> +static struct zpool_ops zswap_zpool_ops = {
> >>> + .evict = zswap_writeback_entry
> >>> +};
> >>> +
> >>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + assert_spin_locked(&zswap_pools_lock);
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> >>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> >>> + continue;
> >>> + if (strncmp(zpool_get_type(pool->zpool), type,
> >>> + sizeof(zswap_zpool_type)))
> >>> + continue;
> >>> + /* if we can't get it, it's about to be destroyed */
> >>> + if (!zswap_pool_get(pool))
> >>> + continue;
> >>> + return pool;
> >>> + }
> >>> +
> >>> + return NULL;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >>> +
> >>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> >>> + if (!pool) {
> >>> + pr_err("pool alloc failed\n");
> >>> + return NULL;
> >>> + }
> >>> +
> >>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> >>> + if (!pool->zpool) {
> >>> + pr_err("%s zpool not available\n", type);
> >>> + goto error;
> >>> + }
> >>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> >>> +
> >>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> >>> + pool->tfm = alloc_percpu(struct crypto_comp *);
> >>> + if (!pool->tfm) {
> >>> + pr_err("percpu alloc failed\n");
> >>> + goto error;
> >>> + }
> >>> +
> >>> + if (zswap_cpu_comp_init(pool))
> >>> + goto error;
> >>> + pr_debug("using %s compressor\n", pool->tfm_name);
> >>> +
> >>> + /* being the current pool takes 1 ref; this func expects the
> >>> + * caller to always add the new pool as the current pool
> >>> + */
> >>> + kref_init(&pool->kref);
> >>> + INIT_LIST_HEAD(&pool->list);
> >>> +
> >>> + zswap_pool_debug("created", pool);
> >>> +
> >>> + return pool;
> >>> +
> >>> +error:
> >>> + free_percpu(pool->tfm);
> >>> + if (pool->zpool)
> >>> + zpool_destroy_pool(pool->zpool);
> >>> + kfree(pool);
> >>> + return NULL;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> >>> +{
> >>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >>> + pr_err("compressor %s not available, using default %s\n",
> >>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> >>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> >>> + sizeof(zswap_compressor));
> >>> + }
> >>> + if (!zpool_has_pool(zswap_zpool_type)) {
> >>> + pr_err("zpool %s not available, using default %s\n",
> >>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> >>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> >>> + sizeof(zswap_zpool_type));
> >>> + }
> >>> +
> >>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> >>> +}
> >>> +
> >>> +static void zswap_pool_destroy(struct zswap_pool *pool)
> >>> +{
> >>> + zswap_pool_debug("destroying", pool);
> >>> +
> >>> + zswap_cpu_comp_destroy(pool);
> >>> + free_percpu(pool->tfm);
> >>> + zpool_destroy_pool(pool->zpool);
> >>> + kfree(pool);
> >>> +}
> >>> +
> >>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> >>> +{
> >>> + return kref_get_unless_zero(&pool->kref);
> >>> +}
> >>> +
> >>> +static void __zswap_pool_release(struct rcu_head *head)
> >>> +{
> >>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> >>> +
> >>> + /* nobody should have been able to get a kref... */
> >>> + WARN_ON(kref_get_unless_zero(&pool->kref));
> >>> +
> >>> + /* pool is now off zswap_pools list and has no references. */
> >>> + zswap_pool_destroy(pool);
> >>> +}
> >>> +
> >>> +static void __zswap_pool_empty(struct kref *kref)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + pool = container_of(kref, typeof(*pool), kref);
> >>> +
> >>> + spin_lock(&zswap_pools_lock);
> >>> +
> >>> + WARN_ON(pool == zswap_pool_current());
> >>> +
> >>> + list_del_rcu(&pool->list);
> >>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> >>> +
> >>> + spin_unlock(&zswap_pools_lock);
> >>> +}
> >>> +
> >>> +static void zswap_pool_put(struct zswap_pool *pool)
> >>> +{
> >>> + kref_put(&pool->kref, __zswap_pool_empty);
> >>> +}
> >>> +
> >>> }
> >>>
> >>> /*********************************
> >>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >>> pgoff_t offset;
> >>> struct zswap_entry *entry;
> >>> struct page *page;
> >>> + struct crypto_comp *tfm;
> >>> u8 *src, *dst;
> >>> unsigned int dlen;
> >>> int ret;
> >>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> >>> /* decompress */
> >>> dlen = PAGE_SIZE;
> >>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >>> dst = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> >>> - entry->length, dst, &dlen);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> + ret = crypto_comp_decompress(tfm, src, entry->length,
> >>> + dst, &dlen);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> kunmap_atomic(dst);
> >>> - zpool_unmap_handle(zswap_pool, entry->handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >>> BUG_ON(ret);
> >>> BUG_ON(dlen != PAGE_SIZE);
> >>>
> >>> @@ -633,6 +882,22 @@ end:
> >>> return ret;
> >>> }
> >>>
> >>> +static int zswap_shrink(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + int ret;
> >>> +
> >>> + pool = zswap_pool_last_get();
> >>> + if (!pool)
> >>> + return -ENOENT;
> >>> +
> >>> + ret = zpool_shrink(pool->zpool, 1, NULL);
> >>> +
> >>> + zswap_pool_put(pool);
> >>> +
> >>> + return ret;
> >>> +}
> >>> +
> >>> /*********************************
> >>> * frontswap hooks
> >>> **********************************/
> >>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> {
> >>> struct zswap_tree *tree = zswap_trees[type];
> >>> struct zswap_entry *entry, *dupentry;
> >>> + struct crypto_comp *tfm;
> >>> int ret;
> >>> unsigned int dlen = PAGE_SIZE, len;
> >>> unsigned long handle;
> >>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> /* reclaim space if needed */
> >>> if (zswap_is_full()) {
> >>> zswap_pool_limit_hit++;
> >>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> >>> + if (zswap_shrink()) {
> >>> zswap_reject_reclaim_fail++;
> >>> ret = -ENOMEM;
> >>> goto reject;
> >>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> goto reject;
> >>> }
> >>>
> >>> + /* if entry is successfully added, it keeps the reference */
> >>> + entry->pool = zswap_pool_current_get();
> >>> + if (!entry->pool) {
> >>> + ret = -EINVAL;
> >>> + goto freepage;
> >>> + }
> >>> +
> >>> /* compress */
> >>> dst = get_cpu_var(zswap_dstmem);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> src = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> >>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> >>> kunmap_atomic(src);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> if (ret) {
> >>> ret = -EINVAL;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>>
> >>> /* store */
> >>> len = dlen + sizeof(struct zswap_header);
> >>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> >>> - &handle);
> >>> + ret = zpool_malloc(entry->pool->zpool, len,
> >>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> >>> if (ret == -ENOSPC) {
> >>> zswap_reject_compress_poor++;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>> if (ret) {
> >>> zswap_reject_alloc_fail++;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> >>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> >>> zhdr->swpentry = swp_entry(type, offset);
> >>> buf = (u8 *)(zhdr + 1);
> >>> memcpy(buf, dst, dlen);
> >>> - zpool_unmap_handle(zswap_pool, handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, handle);
> >>> put_cpu_var(zswap_dstmem);
> >>>
> >>> /* populate entry */
> >>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>>
> >>> /* update stats */
> >>> atomic_inc(&zswap_stored_pages);
> >>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >>> + zswap_update_total_size();
> >>>
> >>> return 0;
> >>>
> >>> -freepage:
> >>> +put_dstmem:
> >>> put_cpu_var(zswap_dstmem);
> >>> + zswap_pool_put(entry->pool);
> >>> +freepage:
> >>> zswap_entry_cache_free(entry);
> >>> reject:
> >>> return ret;
> >>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>> {
> >>> struct zswap_tree *tree = zswap_trees[type];
> >>> struct zswap_entry *entry;
> >>> + struct crypto_comp *tfm;
> >>> u8 *src, *dst;
> >>> unsigned int dlen;
> >>> int ret;
> >>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>>
> >>> /* decompress */
> >>> dlen = PAGE_SIZE;
> >>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >>> dst = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> >>> - dst, &dlen);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> kunmap_atomic(dst);
> >>> - zpool_unmap_handle(zswap_pool, entry->handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >>> BUG_ON(ret);
> >>>
> >>> spin_lock(&tree->lock);
> >>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> >>> zswap_trees[type] = NULL;
> >>> }
> >>>
> >>> -static struct zpool_ops zswap_zpool_ops = {
> >>> - .evict = zswap_writeback_entry
> >>> -};
> >>> -
> >>> static void zswap_frontswap_init(unsigned type)
> >>> {
> >>> struct zswap_tree *tree;
> >>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> >>> **********************************/
> >>> static int __init init_zswap(void)
> >>> {
> >>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >>> + struct zswap_pool *pool;
> >>>
> >>> - pr_info("loading zswap\n");
> >>> -
> >>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >>> - &zswap_zpool_ops);
> >>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> >>> - pr_info("%s zpool not available\n", zswap_zpool_type);
> >>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> >>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >>> - &zswap_zpool_ops);
> >>> - }
> >>> - if (!zswap_pool) {
> >>> - pr_err("%s zpool not available\n", zswap_zpool_type);
> >>> - pr_err("zpool creation failed\n");
> >>> - goto error;
> >>> - }
> >>> - pr_info("using %s pool\n", zswap_zpool_type);
> >>> + pr_info("loading\n");
> >>>
> >>> if (zswap_entry_cache_create()) {
> >>> pr_err("entry cache creation failed\n");
> >>> - goto cachefail;
> >>> + goto cache_fail;
> >>> }
> >>> - if (zswap_comp_init()) {
> >>> - pr_err("compressor initialization failed\n");
> >>> - goto compfail;
> >>> +
> >>> + if (zswap_cpu_dstmem_init()) {
> >>> + pr_err("dstmem alloc failed\n");
> >>> + goto dstmem_fail;
> >>> }
> >>> - if (zswap_cpu_init()) {
> >>> - pr_err("per-cpu initialization failed\n");
> >>> - goto pcpufail;
> >>> +
> >>> + pool = __zswap_pool_create_fallback();
> >>> + if (!pool) {
> >>> + pr_err("pool creation failed\n");
> >>> + goto pool_fail;
> >>> }
> >>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> >>> + zpool_get_type(pool->zpool));
> >>> +
> >>> + list_add(&pool->list, &zswap_pools);
> >>>
> >>> frontswap_register_ops(&zswap_frontswap_ops);
> >>> if (zswap_debugfs_init())
> >>> pr_warn("debugfs initialization failed\n");
> >>> return 0;
> >>> -pcpufail:
> >>> - zswap_comp_exit();
> >>> -compfail:
> >>> +
> >>> +pool_fail:
> >>> + zswap_cpu_dstmem_destroy();
> >>> +dstmem_fail:
> >>> zswap_entry_cache_destroy();
> >>> -cachefail:
> >>> - zpool_destroy_pool(zswap_pool);
> >>> -error:
> >>> +cache_fail:
> >>> return -ENOMEM;
> >>> }
> >>> /* must be late so crypto has time to come up */
> >>> --
> >>> 2.1.0
> >>>
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-11 18:51 ` Seth Jennings
@ 2015-06-18 15:57 ` Seth Jennings
-1 siblings, 0 replies; 22+ messages in thread
From: Seth Jennings @ 2015-06-18 15:57 UTC (permalink / raw)
To: Dan Streetman; +Cc: Andrew Morton, Linux-MM, linux-kernel
On Thu, Jun 11, 2015 at 01:51:45PM -0500, Seth Jennings wrote:
> On Wed, Jun 10, 2015 at 04:54:24PM -0400, Dan Streetman wrote:
> > On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> > > On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> > >> Add dynamic creation of pools. Move the static crypto compression
> > >> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> > >> the pool it's in.
> > >
> > > Seth, as far as the design, from your previous comments I assume you
> > > were thinking of maintaining separate lists of zpools and compressors?
> > > I do see how that will reduce duplication of zpools and compressors,
> > > but it also requires adding a new pointer to each zswap_entry, and
> > > increasing the amount of code to manage each list separately. And the
> > > most common case in zswap will be just a single zpool and compressor,
> > > not repeatedly changing params. What do you think?
> >
> > Any opinion on this patch? If you want, I can break it up so there's
> > a list of zpools and a list of compressors. Either the combined way
> > (this patch) or separate lists works for me, as long as the params are
> > changeable at runtime :-)
>
> I'm still reviewing the code. I was going to test it too but it doesn't
> compile for me:
>
> CC mm/zswap.o
> mm/zswap.c: In function ‘__zswap_pool_create_fallback’:
> mm/zswap.c:605:10: warning: argument to ‘sizeof’ in ‘strncpy’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
> sizeof(zswap_compressor));
> ^
> mm/zswap.c:607:7: error: implicit declaration of function ‘zpool_has_pool’ [-Werror=implicit-function-declaration]
> if (!zpool_has_pool(zswap_zpool_type)) {
> ^
> mm/zswap.c:611:10: warning: argument to ‘sizeof’ in ‘strncpy’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
> sizeof(zswap_zpool_type));
> ^
> mm/zswap.c: At top level:
> mm/zswap.c:664:1: error: expected identifier or ‘(’ before ‘}’ token
> }
> ^
> mm/zswap.c:99:22: warning: ‘zswap_pool’ defined but not used [-Wunused-variable]
> static struct zpool *zswap_pool;
> ^
> mm/zswap.c:531:27: warning: ‘zswap_pool_find_get’ defined but not used [-Wunused-function]
> static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> ^
Dan, I never heard back from you on this, but I figured it out. PATCH
1/5 from your original patchset wasn't pulled in, but you didn't roll it
into this new patch either.
Seth
>
> Seth
>
> >
> >
> > >
> > >>
> > >> This is required by a separate patch which enables changing the
> > >> zswap zpool and compressor params at runtime.
> > >>
> > >> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> > >> ---
> > >> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> > >> 1 file changed, 408 insertions(+), 142 deletions(-)
> > >>
> > >> diff --git a/mm/zswap.c b/mm/zswap.c
> > >> index 2d5727b..fc93770 100644
> > >> --- a/mm/zswap.c
> > >> +++ b/mm/zswap.c
> > >> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> > >> static struct zpool *zswap_pool;
> > >>
> > >> /*********************************
> > >> -* compression functions
> > >> +* data structures
> > >> **********************************/
> > >> -/* per-cpu compression transforms */
> > >> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> > >>
> > >> -enum comp_op {
> > >> - ZSWAP_COMPOP_COMPRESS,
> > >> - ZSWAP_COMPOP_DECOMPRESS
> > >> +struct zswap_pool {
> > >> + struct zpool *zpool;
> > >> + struct kref kref;
> > >> + struct list_head list;
> > >> + struct rcu_head rcu_head;
> > >> + struct notifier_block notifier;
> > >> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> > >> + struct crypto_comp * __percpu *tfm;
> > >> };
> > >>
> > >> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> > >> - u8 *dst, unsigned int *dlen)
> > >> -{
> > >> - struct crypto_comp *tfm;
> > >> - int ret;
> > >> -
> > >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> > >> - switch (op) {
> > >> - case ZSWAP_COMPOP_COMPRESS:
> > >> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> > >> - break;
> > >> - case ZSWAP_COMPOP_DECOMPRESS:
> > >> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> > >> - break;
> > >> - default:
> > >> - ret = -EINVAL;
> > >> - }
> > >> -
> > >> - put_cpu();
> > >> - return ret;
> > >> -}
> > >> -
> > >> -static int __init zswap_comp_init(void)
> > >> -{
> > >> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> > >> - pr_info("%s compressor not available\n", zswap_compressor);
> > >> - /* fall back to default compressor */
> > >> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> > >> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> > >> - /* can't even load the default compressor */
> > >> - return -ENODEV;
> > >> - }
> > >> - pr_info("using %s compressor\n", zswap_compressor);
> > >> -
> > >> - /* alloc percpu transforms */
> > >> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> > >> - if (!zswap_comp_pcpu_tfms)
> > >> - return -ENOMEM;
> > >> - return 0;
> > >> -}
> > >> -
> > >> -static void __init zswap_comp_exit(void)
> > >> -{
> > >> - /* free percpu transforms */
> > >> - free_percpu(zswap_comp_pcpu_tfms);
> > >> -}
> > >> -
> > >> -/*********************************
> > >> -* data structures
> > >> -**********************************/
> > >> /*
> > >> * struct zswap_entry
> > >> *
> > >> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> > >> * page within zswap.
> > >> *
> > >> * rbnode - links the entry into red-black tree for the appropriate swap type
> > >> + * offset - the swap offset for the entry. Index into the red-black tree.
> > >> * refcount - the number of outstanding reference to the entry. This is needed
> > >> * to protect against premature freeing of the entry by code
> > >> * concurrent calls to load, invalidate, and writeback. The lock
> > >> * for the zswap_tree structure that contains the entry must
> > >> * be held while changing the refcount. Since the lock must
> > >> * be held, there is no reason to also make refcount atomic.
> > >> - * offset - the swap offset for the entry. Index into the red-black tree.
> > >> - * handle - zpool allocation handle that stores the compressed page data
> > >> * length - the length in bytes of the compressed page data. Needed during
> > >> * decompression
> > >> + * pool - the zswap_pool the entry's data is in
> > >> + * handle - zpool allocation handle that stores the compressed page data
> > >> */
> > >> struct zswap_entry {
> > >> struct rb_node rbnode;
> > >> pgoff_t offset;
> > >> int refcount;
> > >> unsigned int length;
> > >> + struct zswap_pool *pool;
> > >> unsigned long handle;
> > >> };
> > >>
> > >> @@ -201,6 +156,44 @@ struct zswap_tree {
> > >>
> > >> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> > >>
> > >> +/* RCU-protected iteration */
> > >> +static LIST_HEAD(zswap_pools);
> > >> +/* protects zswap_pools list modification */
> > >> +static DEFINE_SPINLOCK(zswap_pools_lock);
> > >> +
> > >> +/*********************************
> > >> +* helpers and fwd declarations
> > >> +**********************************/
> > >> +
> > >> +#define zswap_pool_debug(msg, p) \
> > >> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> > >> + zpool_get_type((p)->zpool))
> > >> +
> > >> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> > >> +static int zswap_pool_get(struct zswap_pool *pool);
> > >> +static void zswap_pool_put(struct zswap_pool *pool);
> > >> +
> > >> +static bool zswap_is_full(void)
> > >> +{
> > >> + return totalram_pages * zswap_max_pool_percent / 100 <
> > >> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> > >> +}
> > >> +
> > >> +static void zswap_update_total_size(void)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> + u64 total = 0;
> > >> +
> > >> + rcu_read_lock();
> > >> +
> > >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> > >> + total += zpool_get_total_size(pool->zpool);
> > >> +
> > >> + rcu_read_unlock();
> > >> +
> > >> + zswap_pool_total_size = total;
> > >> +}
> > >> +
> > >> /*********************************
> > >> * zswap entry functions
> > >> **********************************/
> > >> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> > >> */
> > >> static void zswap_free_entry(struct zswap_entry *entry)
> > >> {
> > >> - zpool_free(zswap_pool, entry->handle);
> > >> + zpool_free(entry->pool->zpool, entry->handle);
> > >> + zswap_pool_put(entry->pool);
> > >> zswap_entry_cache_free(entry);
> > >> atomic_dec(&zswap_stored_pages);
> > >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> > >> + zswap_update_total_size();
> > >> }
> > >>
> > >> /* caller must hold the tree lock */
> > >> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> > >> **********************************/
> > >> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> > >>
> > >> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> > >> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> > >> {
> > >> - struct crypto_comp *tfm;
> > >> u8 *dst;
> > >>
> > >> switch (action) {
> > >> case CPU_UP_PREPARE:
> > >> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> > >> - if (IS_ERR(tfm)) {
> > >> - pr_err("can't allocate compressor transform\n");
> > >> - return NOTIFY_BAD;
> > >> - }
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> > >> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> > >> if (!dst) {
> > >> pr_err("can't allocate compressor buffer\n");
> > >> - crypto_free_comp(tfm);
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> > >> return NOTIFY_BAD;
> > >> }
> > >> per_cpu(zswap_dstmem, cpu) = dst;
> > >> break;
> > >> case CPU_DEAD:
> > >> case CPU_UP_CANCELED:
> > >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> > >> - if (tfm) {
> > >> - crypto_free_comp(tfm);
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> > >> - }
> > >> dst = per_cpu(zswap_dstmem, cpu);
> > >> kfree(dst);
> > >> per_cpu(zswap_dstmem, cpu) = NULL;
> > >> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> > >> return NOTIFY_OK;
> > >> }
> > >>
> > >> -static int zswap_cpu_notifier(struct notifier_block *nb,
> > >> - unsigned long action, void *pcpu)
> > >> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> > >> + unsigned long action, void *pcpu)
> > >> {
> > >> - unsigned long cpu = (unsigned long)pcpu;
> > >> - return __zswap_cpu_notifier(action, cpu);
> > >> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> > >> }
> > >>
> > >> -static struct notifier_block zswap_cpu_notifier_block = {
> > >> - .notifier_call = zswap_cpu_notifier
> > >> +static struct notifier_block zswap_dstmem_notifier = {
> > >> + .notifier_call = zswap_cpu_dstmem_notifier,
> > >> };
> > >>
> > >> -static int __init zswap_cpu_init(void)
> > >> +static int __init zswap_cpu_dstmem_init(void)
> > >> {
> > >> unsigned long cpu;
> > >>
> > >> cpu_notifier_register_begin();
> > >> for_each_online_cpu(cpu)
> > >> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> > >> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> > >> + NOTIFY_BAD)
> > >> goto cleanup;
> > >> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> > >> + __register_cpu_notifier(&zswap_dstmem_notifier);
> > >> cpu_notifier_register_done();
> > >> return 0;
> > >>
> > >> cleanup:
> > >> for_each_online_cpu(cpu)
> > >> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> > >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> > >> cpu_notifier_register_done();
> > >> return -ENOMEM;
> > >> }
> > >>
> > >> +static void zswap_cpu_dstmem_destroy(void)
> > >> +{
> > >> + unsigned long cpu;
> > >> +
> > >> + cpu_notifier_register_begin();
> > >> + for_each_online_cpu(cpu)
> > >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> > >> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> > >> + cpu_notifier_register_done();
> > >> +}
> > >> +
> > >> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> > >> + unsigned long action, unsigned long cpu)
> > >> +{
> > >> + struct crypto_comp *tfm;
> > >> +
> > >> + switch (action) {
> > >> + case CPU_UP_PREPARE:
> > >> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> > >> + break;
> > >> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> > >> + if (IS_ERR_OR_NULL(tfm)) {
> > >> + pr_err("could not alloc crypto comp %s : %ld\n",
> > >> + pool->tfm_name, PTR_ERR(tfm));
> > >> + return NOTIFY_BAD;
> > >> + }
> > >> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> > >> + break;
> > >> + case CPU_DEAD:
> > >> + case CPU_UP_CANCELED:
> > >> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> > >> + if (!IS_ERR_OR_NULL(tfm))
> > >> + crypto_free_comp(tfm);
> > >> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> > >> + break;
> > >> + default:
> > >> + break;
> > >> + }
> > >> + return NOTIFY_OK;
> > >> +}
> > >> +
> > >> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> > >> + unsigned long action, void *pcpu)
> > >> +{
> > >> + unsigned long cpu = (unsigned long)pcpu;
> > >> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> > >> +
> > >> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> > >> +}
> > >> +
> > >> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> > >> +{
> > >> + unsigned long cpu;
> > >> +
> > >> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> > >> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> > >> +
> > >> + cpu_notifier_register_begin();
> > >> + for_each_online_cpu(cpu)
> > >> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> > >> + NOTIFY_BAD)
> > >> + goto cleanup;
> > >> + __register_cpu_notifier(&pool->notifier);
> > >> + cpu_notifier_register_done();
> > >> + return 0;
> > >> +
> > >> +cleanup:
> > >> + for_each_online_cpu(cpu)
> > >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> > >> + cpu_notifier_register_done();
> > >> + return -ENOMEM;
> > >> +}
> > >> +
> > >> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> > >> +{
> > >> + unsigned long cpu;
> > >> +
> > >> + cpu_notifier_register_begin();
> > >> + for_each_online_cpu(cpu)
> > >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> > >> + __unregister_cpu_notifier(&pool->notifier);
> > >> + cpu_notifier_register_done();
> > >> +}
> > >> +
> > >> /*********************************
> > >> -* helpers
> > >> +* pool functions
> > >> **********************************/
> > >> -static bool zswap_is_full(void)
> > >> +
> > >> +static struct zswap_pool *__zswap_pool_current(void)
> > >> {
> > >> - return totalram_pages * zswap_max_pool_percent / 100 <
> > >> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> > >> + WARN_ON(!pool);
> > >> +
> > >> + return pool;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_current(void)
> > >> +{
> > >> + assert_spin_locked(&zswap_pools_lock);
> > >> +
> > >> + return __zswap_pool_current();
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_current_get(void)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + rcu_read_lock();
> > >> +
> > >> + pool = __zswap_pool_current();
> > >> + if (!pool || !zswap_pool_get(pool))
> > >> + pool = NULL;
> > >> +
> > >> + rcu_read_unlock();
> > >> +
> > >> + return pool;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_last_get(void)
> > >> +{
> > >> + struct zswap_pool *pool, *last = NULL;
> > >> +
> > >> + rcu_read_lock();
> > >> +
> > >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> > >> + last = pool;
> > >> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> > >> + last = NULL;
> > >> +
> > >> + rcu_read_unlock();
> > >> +
> > >> + return last;
> > >> +}
> > >> +
> > >> +static struct zpool_ops zswap_zpool_ops = {
> > >> + .evict = zswap_writeback_entry
> > >> +};
> > >> +
> > >> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + assert_spin_locked(&zswap_pools_lock);
> > >> +
> > >> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> > >> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> > >> + continue;
> > >> + if (strncmp(zpool_get_type(pool->zpool), type,
> > >> + sizeof(zswap_zpool_type)))
> > >> + continue;
> > >> + /* if we can't get it, it's about to be destroyed */
> > >> + if (!zswap_pool_get(pool))
> > >> + continue;
> > >> + return pool;
> > >> + }
> > >> +
> > >> + return NULL;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> > >> +
> > >> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> > >> + if (!pool) {
> > >> + pr_err("pool alloc failed\n");
> > >> + return NULL;
> > >> + }
> > >> +
> > >> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> > >> + if (!pool->zpool) {
> > >> + pr_err("%s zpool not available\n", type);
> > >> + goto error;
> > >> + }
> > >> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> > >> +
> > >> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> > >> + pool->tfm = alloc_percpu(struct crypto_comp *);
> > >> + if (!pool->tfm) {
> > >> + pr_err("percpu alloc failed\n");
> > >> + goto error;
> > >> + }
> > >> +
> > >> + if (zswap_cpu_comp_init(pool))
> > >> + goto error;
> > >> + pr_debug("using %s compressor\n", pool->tfm_name);
> > >> +
> > >> + /* being the current pool takes 1 ref; this func expects the
> > >> + * caller to always add the new pool as the current pool
> > >> + */
> > >> + kref_init(&pool->kref);
> > >> + INIT_LIST_HEAD(&pool->list);
> > >> +
> > >> + zswap_pool_debug("created", pool);
> > >> +
> > >> + return pool;
> > >> +
> > >> +error:
> > >> + free_percpu(pool->tfm);
> > >> + if (pool->zpool)
> > >> + zpool_destroy_pool(pool->zpool);
> > >> + kfree(pool);
> > >> + return NULL;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> > >> +{
> > >> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> > >> + pr_err("compressor %s not available, using default %s\n",
> > >> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> > >> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> > >> + sizeof(zswap_compressor));
> > >> + }
> > >> + if (!zpool_has_pool(zswap_zpool_type)) {
> > >> + pr_err("zpool %s not available, using default %s\n",
> > >> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> > >> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> > >> + sizeof(zswap_zpool_type));
> > >> + }
> > >> +
> > >> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> > >> +}
> > >> +
> > >> +static void zswap_pool_destroy(struct zswap_pool *pool)
> > >> +{
> > >> + zswap_pool_debug("destroying", pool);
> > >> +
> > >> + zswap_cpu_comp_destroy(pool);
> > >> + free_percpu(pool->tfm);
> > >> + zpool_destroy_pool(pool->zpool);
> > >> + kfree(pool);
> > >> +}
> > >> +
> > >> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> > >> +{
> > >> + return kref_get_unless_zero(&pool->kref);
> > >> +}
> > >> +
> > >> +static void __zswap_pool_release(struct rcu_head *head)
> > >> +{
> > >> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> > >> +
> > >> + /* nobody should have been able to get a kref... */
> > >> + WARN_ON(kref_get_unless_zero(&pool->kref));
> > >> +
> > >> + /* pool is now off zswap_pools list and has no references. */
> > >> + zswap_pool_destroy(pool);
> > >> +}
> > >> +
> > >> +static void __zswap_pool_empty(struct kref *kref)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + pool = container_of(kref, typeof(*pool), kref);
> > >> +
> > >> + spin_lock(&zswap_pools_lock);
> > >> +
> > >> + WARN_ON(pool == zswap_pool_current());
> > >> +
> > >> + list_del_rcu(&pool->list);
> > >> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> > >> +
> > >> + spin_unlock(&zswap_pools_lock);
> > >> +}
> > >> +
> > >> +static void zswap_pool_put(struct zswap_pool *pool)
> > >> +{
> > >> + kref_put(&pool->kref, __zswap_pool_empty);
> > >> +}
> > >> +
> > >> }
> > >>
> > >> /*********************************
> > >> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> > >> pgoff_t offset;
> > >> struct zswap_entry *entry;
> > >> struct page *page;
> > >> + struct crypto_comp *tfm;
> > >> u8 *src, *dst;
> > >> unsigned int dlen;
> > >> int ret;
> > >> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> > >> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> > >> /* decompress */
> > >> dlen = PAGE_SIZE;
> > >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> > >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> > >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> > >> dst = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> > >> - entry->length, dst, &dlen);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> + ret = crypto_comp_decompress(tfm, src, entry->length,
> > >> + dst, &dlen);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> kunmap_atomic(dst);
> > >> - zpool_unmap_handle(zswap_pool, entry->handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> > >> BUG_ON(ret);
> > >> BUG_ON(dlen != PAGE_SIZE);
> > >>
> > >> @@ -633,6 +882,22 @@ end:
> > >> return ret;
> > >> }
> > >>
> > >> +static int zswap_shrink(void)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> + int ret;
> > >> +
> > >> + pool = zswap_pool_last_get();
> > >> + if (!pool)
> > >> + return -ENOENT;
> > >> +
> > >> + ret = zpool_shrink(pool->zpool, 1, NULL);
> > >> +
> > >> + zswap_pool_put(pool);
> > >> +
> > >> + return ret;
> > >> +}
> > >> +
> > >> /*********************************
> > >> * frontswap hooks
> > >> **********************************/
> > >> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> {
> > >> struct zswap_tree *tree = zswap_trees[type];
> > >> struct zswap_entry *entry, *dupentry;
> > >> + struct crypto_comp *tfm;
> > >> int ret;
> > >> unsigned int dlen = PAGE_SIZE, len;
> > >> unsigned long handle;
> > >> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> /* reclaim space if needed */
> > >> if (zswap_is_full()) {
> > >> zswap_pool_limit_hit++;
> > >> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> > >> + if (zswap_shrink()) {
> > >> zswap_reject_reclaim_fail++;
> > >> ret = -ENOMEM;
> > >> goto reject;
> > >> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> goto reject;
> > >> }
> > >>
> > >> + /* if entry is successfully added, it keeps the reference */
> > >> + entry->pool = zswap_pool_current_get();
> > >> + if (!entry->pool) {
> > >> + ret = -EINVAL;
> > >> + goto freepage;
> > >> + }
> > >> +
> > >> /* compress */
> > >> dst = get_cpu_var(zswap_dstmem);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> src = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> > >> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> > >> kunmap_atomic(src);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> if (ret) {
> > >> ret = -EINVAL;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >>
> > >> /* store */
> > >> len = dlen + sizeof(struct zswap_header);
> > >> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> > >> - &handle);
> > >> + ret = zpool_malloc(entry->pool->zpool, len,
> > >> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> > >> if (ret == -ENOSPC) {
> > >> zswap_reject_compress_poor++;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >> if (ret) {
> > >> zswap_reject_alloc_fail++;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> > >> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> > >> zhdr->swpentry = swp_entry(type, offset);
> > >> buf = (u8 *)(zhdr + 1);
> > >> memcpy(buf, dst, dlen);
> > >> - zpool_unmap_handle(zswap_pool, handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, handle);
> > >> put_cpu_var(zswap_dstmem);
> > >>
> > >> /* populate entry */
> > >> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >>
> > >> /* update stats */
> > >> atomic_inc(&zswap_stored_pages);
> > >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> > >> + zswap_update_total_size();
> > >>
> > >> return 0;
> > >>
> > >> -freepage:
> > >> +put_dstmem:
> > >> put_cpu_var(zswap_dstmem);
> > >> + zswap_pool_put(entry->pool);
> > >> +freepage:
> > >> zswap_entry_cache_free(entry);
> > >> reject:
> > >> return ret;
> > >> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> > >> {
> > >> struct zswap_tree *tree = zswap_trees[type];
> > >> struct zswap_entry *entry;
> > >> + struct crypto_comp *tfm;
> > >> u8 *src, *dst;
> > >> unsigned int dlen;
> > >> int ret;
> > >> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> > >>
> > >> /* decompress */
> > >> dlen = PAGE_SIZE;
> > >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> > >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> > >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> > >> dst = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> > >> - dst, &dlen);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> kunmap_atomic(dst);
> > >> - zpool_unmap_handle(zswap_pool, entry->handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> > >> BUG_ON(ret);
> > >>
> > >> spin_lock(&tree->lock);
> > >> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> > >> zswap_trees[type] = NULL;
> > >> }
> > >>
> > >> -static struct zpool_ops zswap_zpool_ops = {
> > >> - .evict = zswap_writeback_entry
> > >> -};
> > >> -
> > >> static void zswap_frontswap_init(unsigned type)
> > >> {
> > >> struct zswap_tree *tree;
> > >> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> > >> **********************************/
> > >> static int __init init_zswap(void)
> > >> {
> > >> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> > >> + struct zswap_pool *pool;
> > >>
> > >> - pr_info("loading zswap\n");
> > >> -
> > >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> > >> - &zswap_zpool_ops);
> > >> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> > >> - pr_info("%s zpool not available\n", zswap_zpool_type);
> > >> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> > >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> > >> - &zswap_zpool_ops);
> > >> - }
> > >> - if (!zswap_pool) {
> > >> - pr_err("%s zpool not available\n", zswap_zpool_type);
> > >> - pr_err("zpool creation failed\n");
> > >> - goto error;
> > >> - }
> > >> - pr_info("using %s pool\n", zswap_zpool_type);
> > >> + pr_info("loading\n");
> > >>
> > >> if (zswap_entry_cache_create()) {
> > >> pr_err("entry cache creation failed\n");
> > >> - goto cachefail;
> > >> + goto cache_fail;
> > >> }
> > >> - if (zswap_comp_init()) {
> > >> - pr_err("compressor initialization failed\n");
> > >> - goto compfail;
> > >> +
> > >> + if (zswap_cpu_dstmem_init()) {
> > >> + pr_err("dstmem alloc failed\n");
> > >> + goto dstmem_fail;
> > >> }
> > >> - if (zswap_cpu_init()) {
> > >> - pr_err("per-cpu initialization failed\n");
> > >> - goto pcpufail;
> > >> +
> > >> + pool = __zswap_pool_create_fallback();
> > >> + if (!pool) {
> > >> + pr_err("pool creation failed\n");
> > >> + goto pool_fail;
> > >> }
> > >> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> > >> + zpool_get_type(pool->zpool));
> > >> +
> > >> + list_add(&pool->list, &zswap_pools);
> > >>
> > >> frontswap_register_ops(&zswap_frontswap_ops);
> > >> if (zswap_debugfs_init())
> > >> pr_warn("debugfs initialization failed\n");
> > >> return 0;
> > >> -pcpufail:
> > >> - zswap_comp_exit();
> > >> -compfail:
> > >> +
> > >> +pool_fail:
> > >> + zswap_cpu_dstmem_destroy();
> > >> +dstmem_fail:
> > >> zswap_entry_cache_destroy();
> > >> -cachefail:
> > >> - zpool_destroy_pool(zswap_pool);
> > >> -error:
> > >> +cache_fail:
> > >> return -ENOMEM;
> > >> }
> > >> /* must be late so crypto has time to come up */
> > >> --
> > >> 2.1.0
> > >>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-18 15:57 ` Seth Jennings
0 siblings, 0 replies; 22+ messages in thread
From: Seth Jennings @ 2015-06-18 15:57 UTC (permalink / raw)
To: Dan Streetman; +Cc: Andrew Morton, Linux-MM, linux-kernel
On Thu, Jun 11, 2015 at 01:51:45PM -0500, Seth Jennings wrote:
> On Wed, Jun 10, 2015 at 04:54:24PM -0400, Dan Streetman wrote:
> > On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> > > On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> > >> Add dynamic creation of pools. Move the static crypto compression
> > >> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> > >> the pool it's in.
> > >
> > > Seth, as far as the design, from your previous comments I assume you
> > > were thinking of maintaining separate lists of zpools and compressors?
> > > I do see how that will reduce duplication of zpools and compressors,
> > > but it also requires adding a new pointer to each zswap_entry, and
> > > increasing the amount of code to manage each list separately. And the
> > > most common case in zswap will be just a single zpool and compressor,
> > > not repeatedly changing params. What do you think?
> >
> > Any opinion on this patch? If you want, I can break it up so there's
> > a list of zpools and a list of compressors. Either the combined way
> > (this patch) or separate lists works for me, as long as the params are
> > changeable at runtime :-)
>
> I'm still reviewing the code. I was going to test it too but it doesn't
> compile for me:
>
> CC mm/zswap.o
> mm/zswap.c: In function a??__zswap_pool_create_fallbacka??:
> mm/zswap.c:605:10: warning: argument to a??sizeofa?? in a??strncpya?? call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
> sizeof(zswap_compressor));
> ^
> mm/zswap.c:607:7: error: implicit declaration of function a??zpool_has_poola?? [-Werror=implicit-function-declaration]
> if (!zpool_has_pool(zswap_zpool_type)) {
> ^
> mm/zswap.c:611:10: warning: argument to a??sizeofa?? in a??strncpya?? call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
> sizeof(zswap_zpool_type));
> ^
> mm/zswap.c: At top level:
> mm/zswap.c:664:1: error: expected identifier or a??(a?? before a??}a?? token
> }
> ^
> mm/zswap.c:99:22: warning: a??zswap_poola?? defined but not used [-Wunused-variable]
> static struct zpool *zswap_pool;
> ^
> mm/zswap.c:531:27: warning: a??zswap_pool_find_geta?? defined but not used [-Wunused-function]
> static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> ^
Dan, I never heard back from you on this, but I figured it out. PATCH
1/5 from your original patchset wasn't pulled in, but you didn't roll it
into this new patch either.
Seth
>
> Seth
>
> >
> >
> > >
> > >>
> > >> This is required by a separate patch which enables changing the
> > >> zswap zpool and compressor params at runtime.
> > >>
> > >> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> > >> ---
> > >> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> > >> 1 file changed, 408 insertions(+), 142 deletions(-)
> > >>
> > >> diff --git a/mm/zswap.c b/mm/zswap.c
> > >> index 2d5727b..fc93770 100644
> > >> --- a/mm/zswap.c
> > >> +++ b/mm/zswap.c
> > >> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> > >> static struct zpool *zswap_pool;
> > >>
> > >> /*********************************
> > >> -* compression functions
> > >> +* data structures
> > >> **********************************/
> > >> -/* per-cpu compression transforms */
> > >> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> > >>
> > >> -enum comp_op {
> > >> - ZSWAP_COMPOP_COMPRESS,
> > >> - ZSWAP_COMPOP_DECOMPRESS
> > >> +struct zswap_pool {
> > >> + struct zpool *zpool;
> > >> + struct kref kref;
> > >> + struct list_head list;
> > >> + struct rcu_head rcu_head;
> > >> + struct notifier_block notifier;
> > >> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> > >> + struct crypto_comp * __percpu *tfm;
> > >> };
> > >>
> > >> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> > >> - u8 *dst, unsigned int *dlen)
> > >> -{
> > >> - struct crypto_comp *tfm;
> > >> - int ret;
> > >> -
> > >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> > >> - switch (op) {
> > >> - case ZSWAP_COMPOP_COMPRESS:
> > >> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> > >> - break;
> > >> - case ZSWAP_COMPOP_DECOMPRESS:
> > >> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> > >> - break;
> > >> - default:
> > >> - ret = -EINVAL;
> > >> - }
> > >> -
> > >> - put_cpu();
> > >> - return ret;
> > >> -}
> > >> -
> > >> -static int __init zswap_comp_init(void)
> > >> -{
> > >> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> > >> - pr_info("%s compressor not available\n", zswap_compressor);
> > >> - /* fall back to default compressor */
> > >> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> > >> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> > >> - /* can't even load the default compressor */
> > >> - return -ENODEV;
> > >> - }
> > >> - pr_info("using %s compressor\n", zswap_compressor);
> > >> -
> > >> - /* alloc percpu transforms */
> > >> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> > >> - if (!zswap_comp_pcpu_tfms)
> > >> - return -ENOMEM;
> > >> - return 0;
> > >> -}
> > >> -
> > >> -static void __init zswap_comp_exit(void)
> > >> -{
> > >> - /* free percpu transforms */
> > >> - free_percpu(zswap_comp_pcpu_tfms);
> > >> -}
> > >> -
> > >> -/*********************************
> > >> -* data structures
> > >> -**********************************/
> > >> /*
> > >> * struct zswap_entry
> > >> *
> > >> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> > >> * page within zswap.
> > >> *
> > >> * rbnode - links the entry into red-black tree for the appropriate swap type
> > >> + * offset - the swap offset for the entry. Index into the red-black tree.
> > >> * refcount - the number of outstanding reference to the entry. This is needed
> > >> * to protect against premature freeing of the entry by code
> > >> * concurrent calls to load, invalidate, and writeback. The lock
> > >> * for the zswap_tree structure that contains the entry must
> > >> * be held while changing the refcount. Since the lock must
> > >> * be held, there is no reason to also make refcount atomic.
> > >> - * offset - the swap offset for the entry. Index into the red-black tree.
> > >> - * handle - zpool allocation handle that stores the compressed page data
> > >> * length - the length in bytes of the compressed page data. Needed during
> > >> * decompression
> > >> + * pool - the zswap_pool the entry's data is in
> > >> + * handle - zpool allocation handle that stores the compressed page data
> > >> */
> > >> struct zswap_entry {
> > >> struct rb_node rbnode;
> > >> pgoff_t offset;
> > >> int refcount;
> > >> unsigned int length;
> > >> + struct zswap_pool *pool;
> > >> unsigned long handle;
> > >> };
> > >>
> > >> @@ -201,6 +156,44 @@ struct zswap_tree {
> > >>
> > >> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> > >>
> > >> +/* RCU-protected iteration */
> > >> +static LIST_HEAD(zswap_pools);
> > >> +/* protects zswap_pools list modification */
> > >> +static DEFINE_SPINLOCK(zswap_pools_lock);
> > >> +
> > >> +/*********************************
> > >> +* helpers and fwd declarations
> > >> +**********************************/
> > >> +
> > >> +#define zswap_pool_debug(msg, p) \
> > >> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> > >> + zpool_get_type((p)->zpool))
> > >> +
> > >> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> > >> +static int zswap_pool_get(struct zswap_pool *pool);
> > >> +static void zswap_pool_put(struct zswap_pool *pool);
> > >> +
> > >> +static bool zswap_is_full(void)
> > >> +{
> > >> + return totalram_pages * zswap_max_pool_percent / 100 <
> > >> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> > >> +}
> > >> +
> > >> +static void zswap_update_total_size(void)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> + u64 total = 0;
> > >> +
> > >> + rcu_read_lock();
> > >> +
> > >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> > >> + total += zpool_get_total_size(pool->zpool);
> > >> +
> > >> + rcu_read_unlock();
> > >> +
> > >> + zswap_pool_total_size = total;
> > >> +}
> > >> +
> > >> /*********************************
> > >> * zswap entry functions
> > >> **********************************/
> > >> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> > >> */
> > >> static void zswap_free_entry(struct zswap_entry *entry)
> > >> {
> > >> - zpool_free(zswap_pool, entry->handle);
> > >> + zpool_free(entry->pool->zpool, entry->handle);
> > >> + zswap_pool_put(entry->pool);
> > >> zswap_entry_cache_free(entry);
> > >> atomic_dec(&zswap_stored_pages);
> > >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> > >> + zswap_update_total_size();
> > >> }
> > >>
> > >> /* caller must hold the tree lock */
> > >> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> > >> **********************************/
> > >> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> > >>
> > >> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> > >> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> > >> {
> > >> - struct crypto_comp *tfm;
> > >> u8 *dst;
> > >>
> > >> switch (action) {
> > >> case CPU_UP_PREPARE:
> > >> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> > >> - if (IS_ERR(tfm)) {
> > >> - pr_err("can't allocate compressor transform\n");
> > >> - return NOTIFY_BAD;
> > >> - }
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> > >> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> > >> if (!dst) {
> > >> pr_err("can't allocate compressor buffer\n");
> > >> - crypto_free_comp(tfm);
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> > >> return NOTIFY_BAD;
> > >> }
> > >> per_cpu(zswap_dstmem, cpu) = dst;
> > >> break;
> > >> case CPU_DEAD:
> > >> case CPU_UP_CANCELED:
> > >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> > >> - if (tfm) {
> > >> - crypto_free_comp(tfm);
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> > >> - }
> > >> dst = per_cpu(zswap_dstmem, cpu);
> > >> kfree(dst);
> > >> per_cpu(zswap_dstmem, cpu) = NULL;
> > >> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> > >> return NOTIFY_OK;
> > >> }
> > >>
> > >> -static int zswap_cpu_notifier(struct notifier_block *nb,
> > >> - unsigned long action, void *pcpu)
> > >> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> > >> + unsigned long action, void *pcpu)
> > >> {
> > >> - unsigned long cpu = (unsigned long)pcpu;
> > >> - return __zswap_cpu_notifier(action, cpu);
> > >> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> > >> }
> > >>
> > >> -static struct notifier_block zswap_cpu_notifier_block = {
> > >> - .notifier_call = zswap_cpu_notifier
> > >> +static struct notifier_block zswap_dstmem_notifier = {
> > >> + .notifier_call = zswap_cpu_dstmem_notifier,
> > >> };
> > >>
> > >> -static int __init zswap_cpu_init(void)
> > >> +static int __init zswap_cpu_dstmem_init(void)
> > >> {
> > >> unsigned long cpu;
> > >>
> > >> cpu_notifier_register_begin();
> > >> for_each_online_cpu(cpu)
> > >> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> > >> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> > >> + NOTIFY_BAD)
> > >> goto cleanup;
> > >> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> > >> + __register_cpu_notifier(&zswap_dstmem_notifier);
> > >> cpu_notifier_register_done();
> > >> return 0;
> > >>
> > >> cleanup:
> > >> for_each_online_cpu(cpu)
> > >> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> > >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> > >> cpu_notifier_register_done();
> > >> return -ENOMEM;
> > >> }
> > >>
> > >> +static void zswap_cpu_dstmem_destroy(void)
> > >> +{
> > >> + unsigned long cpu;
> > >> +
> > >> + cpu_notifier_register_begin();
> > >> + for_each_online_cpu(cpu)
> > >> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> > >> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> > >> + cpu_notifier_register_done();
> > >> +}
> > >> +
> > >> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> > >> + unsigned long action, unsigned long cpu)
> > >> +{
> > >> + struct crypto_comp *tfm;
> > >> +
> > >> + switch (action) {
> > >> + case CPU_UP_PREPARE:
> > >> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> > >> + break;
> > >> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> > >> + if (IS_ERR_OR_NULL(tfm)) {
> > >> + pr_err("could not alloc crypto comp %s : %ld\n",
> > >> + pool->tfm_name, PTR_ERR(tfm));
> > >> + return NOTIFY_BAD;
> > >> + }
> > >> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> > >> + break;
> > >> + case CPU_DEAD:
> > >> + case CPU_UP_CANCELED:
> > >> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> > >> + if (!IS_ERR_OR_NULL(tfm))
> > >> + crypto_free_comp(tfm);
> > >> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> > >> + break;
> > >> + default:
> > >> + break;
> > >> + }
> > >> + return NOTIFY_OK;
> > >> +}
> > >> +
> > >> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> > >> + unsigned long action, void *pcpu)
> > >> +{
> > >> + unsigned long cpu = (unsigned long)pcpu;
> > >> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> > >> +
> > >> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> > >> +}
> > >> +
> > >> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> > >> +{
> > >> + unsigned long cpu;
> > >> +
> > >> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> > >> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> > >> +
> > >> + cpu_notifier_register_begin();
> > >> + for_each_online_cpu(cpu)
> > >> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> > >> + NOTIFY_BAD)
> > >> + goto cleanup;
> > >> + __register_cpu_notifier(&pool->notifier);
> > >> + cpu_notifier_register_done();
> > >> + return 0;
> > >> +
> > >> +cleanup:
> > >> + for_each_online_cpu(cpu)
> > >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> > >> + cpu_notifier_register_done();
> > >> + return -ENOMEM;
> > >> +}
> > >> +
> > >> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> > >> +{
> > >> + unsigned long cpu;
> > >> +
> > >> + cpu_notifier_register_begin();
> > >> + for_each_online_cpu(cpu)
> > >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> > >> + __unregister_cpu_notifier(&pool->notifier);
> > >> + cpu_notifier_register_done();
> > >> +}
> > >> +
> > >> /*********************************
> > >> -* helpers
> > >> +* pool functions
> > >> **********************************/
> > >> -static bool zswap_is_full(void)
> > >> +
> > >> +static struct zswap_pool *__zswap_pool_current(void)
> > >> {
> > >> - return totalram_pages * zswap_max_pool_percent / 100 <
> > >> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> > >> + WARN_ON(!pool);
> > >> +
> > >> + return pool;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_current(void)
> > >> +{
> > >> + assert_spin_locked(&zswap_pools_lock);
> > >> +
> > >> + return __zswap_pool_current();
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_current_get(void)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + rcu_read_lock();
> > >> +
> > >> + pool = __zswap_pool_current();
> > >> + if (!pool || !zswap_pool_get(pool))
> > >> + pool = NULL;
> > >> +
> > >> + rcu_read_unlock();
> > >> +
> > >> + return pool;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_last_get(void)
> > >> +{
> > >> + struct zswap_pool *pool, *last = NULL;
> > >> +
> > >> + rcu_read_lock();
> > >> +
> > >> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> > >> + last = pool;
> > >> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> > >> + last = NULL;
> > >> +
> > >> + rcu_read_unlock();
> > >> +
> > >> + return last;
> > >> +}
> > >> +
> > >> +static struct zpool_ops zswap_zpool_ops = {
> > >> + .evict = zswap_writeback_entry
> > >> +};
> > >> +
> > >> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + assert_spin_locked(&zswap_pools_lock);
> > >> +
> > >> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> > >> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> > >> + continue;
> > >> + if (strncmp(zpool_get_type(pool->zpool), type,
> > >> + sizeof(zswap_zpool_type)))
> > >> + continue;
> > >> + /* if we can't get it, it's about to be destroyed */
> > >> + if (!zswap_pool_get(pool))
> > >> + continue;
> > >> + return pool;
> > >> + }
> > >> +
> > >> + return NULL;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> > >> +
> > >> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> > >> + if (!pool) {
> > >> + pr_err("pool alloc failed\n");
> > >> + return NULL;
> > >> + }
> > >> +
> > >> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> > >> + if (!pool->zpool) {
> > >> + pr_err("%s zpool not available\n", type);
> > >> + goto error;
> > >> + }
> > >> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> > >> +
> > >> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> > >> + pool->tfm = alloc_percpu(struct crypto_comp *);
> > >> + if (!pool->tfm) {
> > >> + pr_err("percpu alloc failed\n");
> > >> + goto error;
> > >> + }
> > >> +
> > >> + if (zswap_cpu_comp_init(pool))
> > >> + goto error;
> > >> + pr_debug("using %s compressor\n", pool->tfm_name);
> > >> +
> > >> + /* being the current pool takes 1 ref; this func expects the
> > >> + * caller to always add the new pool as the current pool
> > >> + */
> > >> + kref_init(&pool->kref);
> > >> + INIT_LIST_HEAD(&pool->list);
> > >> +
> > >> + zswap_pool_debug("created", pool);
> > >> +
> > >> + return pool;
> > >> +
> > >> +error:
> > >> + free_percpu(pool->tfm);
> > >> + if (pool->zpool)
> > >> + zpool_destroy_pool(pool->zpool);
> > >> + kfree(pool);
> > >> + return NULL;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> > >> +{
> > >> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> > >> + pr_err("compressor %s not available, using default %s\n",
> > >> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> > >> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> > >> + sizeof(zswap_compressor));
> > >> + }
> > >> + if (!zpool_has_pool(zswap_zpool_type)) {
> > >> + pr_err("zpool %s not available, using default %s\n",
> > >> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> > >> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> > >> + sizeof(zswap_zpool_type));
> > >> + }
> > >> +
> > >> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> > >> +}
> > >> +
> > >> +static void zswap_pool_destroy(struct zswap_pool *pool)
> > >> +{
> > >> + zswap_pool_debug("destroying", pool);
> > >> +
> > >> + zswap_cpu_comp_destroy(pool);
> > >> + free_percpu(pool->tfm);
> > >> + zpool_destroy_pool(pool->zpool);
> > >> + kfree(pool);
> > >> +}
> > >> +
> > >> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> > >> +{
> > >> + return kref_get_unless_zero(&pool->kref);
> > >> +}
> > >> +
> > >> +static void __zswap_pool_release(struct rcu_head *head)
> > >> +{
> > >> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> > >> +
> > >> + /* nobody should have been able to get a kref... */
> > >> + WARN_ON(kref_get_unless_zero(&pool->kref));
> > >> +
> > >> + /* pool is now off zswap_pools list and has no references. */
> > >> + zswap_pool_destroy(pool);
> > >> +}
> > >> +
> > >> +static void __zswap_pool_empty(struct kref *kref)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> +
> > >> + pool = container_of(kref, typeof(*pool), kref);
> > >> +
> > >> + spin_lock(&zswap_pools_lock);
> > >> +
> > >> + WARN_ON(pool == zswap_pool_current());
> > >> +
> > >> + list_del_rcu(&pool->list);
> > >> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> > >> +
> > >> + spin_unlock(&zswap_pools_lock);
> > >> +}
> > >> +
> > >> +static void zswap_pool_put(struct zswap_pool *pool)
> > >> +{
> > >> + kref_put(&pool->kref, __zswap_pool_empty);
> > >> +}
> > >> +
> > >> }
> > >>
> > >> /*********************************
> > >> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> > >> pgoff_t offset;
> > >> struct zswap_entry *entry;
> > >> struct page *page;
> > >> + struct crypto_comp *tfm;
> > >> u8 *src, *dst;
> > >> unsigned int dlen;
> > >> int ret;
> > >> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> > >> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> > >> /* decompress */
> > >> dlen = PAGE_SIZE;
> > >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> > >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> > >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> > >> dst = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> > >> - entry->length, dst, &dlen);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> + ret = crypto_comp_decompress(tfm, src, entry->length,
> > >> + dst, &dlen);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> kunmap_atomic(dst);
> > >> - zpool_unmap_handle(zswap_pool, entry->handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> > >> BUG_ON(ret);
> > >> BUG_ON(dlen != PAGE_SIZE);
> > >>
> > >> @@ -633,6 +882,22 @@ end:
> > >> return ret;
> > >> }
> > >>
> > >> +static int zswap_shrink(void)
> > >> +{
> > >> + struct zswap_pool *pool;
> > >> + int ret;
> > >> +
> > >> + pool = zswap_pool_last_get();
> > >> + if (!pool)
> > >> + return -ENOENT;
> > >> +
> > >> + ret = zpool_shrink(pool->zpool, 1, NULL);
> > >> +
> > >> + zswap_pool_put(pool);
> > >> +
> > >> + return ret;
> > >> +}
> > >> +
> > >> /*********************************
> > >> * frontswap hooks
> > >> **********************************/
> > >> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> {
> > >> struct zswap_tree *tree = zswap_trees[type];
> > >> struct zswap_entry *entry, *dupentry;
> > >> + struct crypto_comp *tfm;
> > >> int ret;
> > >> unsigned int dlen = PAGE_SIZE, len;
> > >> unsigned long handle;
> > >> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> /* reclaim space if needed */
> > >> if (zswap_is_full()) {
> > >> zswap_pool_limit_hit++;
> > >> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> > >> + if (zswap_shrink()) {
> > >> zswap_reject_reclaim_fail++;
> > >> ret = -ENOMEM;
> > >> goto reject;
> > >> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> goto reject;
> > >> }
> > >>
> > >> + /* if entry is successfully added, it keeps the reference */
> > >> + entry->pool = zswap_pool_current_get();
> > >> + if (!entry->pool) {
> > >> + ret = -EINVAL;
> > >> + goto freepage;
> > >> + }
> > >> +
> > >> /* compress */
> > >> dst = get_cpu_var(zswap_dstmem);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> src = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> > >> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> > >> kunmap_atomic(src);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> if (ret) {
> > >> ret = -EINVAL;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >>
> > >> /* store */
> > >> len = dlen + sizeof(struct zswap_header);
> > >> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> > >> - &handle);
> > >> + ret = zpool_malloc(entry->pool->zpool, len,
> > >> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> > >> if (ret == -ENOSPC) {
> > >> zswap_reject_compress_poor++;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >> if (ret) {
> > >> zswap_reject_alloc_fail++;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> > >> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> > >> zhdr->swpentry = swp_entry(type, offset);
> > >> buf = (u8 *)(zhdr + 1);
> > >> memcpy(buf, dst, dlen);
> > >> - zpool_unmap_handle(zswap_pool, handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, handle);
> > >> put_cpu_var(zswap_dstmem);
> > >>
> > >> /* populate entry */
> > >> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >>
> > >> /* update stats */
> > >> atomic_inc(&zswap_stored_pages);
> > >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> > >> + zswap_update_total_size();
> > >>
> > >> return 0;
> > >>
> > >> -freepage:
> > >> +put_dstmem:
> > >> put_cpu_var(zswap_dstmem);
> > >> + zswap_pool_put(entry->pool);
> > >> +freepage:
> > >> zswap_entry_cache_free(entry);
> > >> reject:
> > >> return ret;
> > >> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> > >> {
> > >> struct zswap_tree *tree = zswap_trees[type];
> > >> struct zswap_entry *entry;
> > >> + struct crypto_comp *tfm;
> > >> u8 *src, *dst;
> > >> unsigned int dlen;
> > >> int ret;
> > >> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> > >>
> > >> /* decompress */
> > >> dlen = PAGE_SIZE;
> > >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> > >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> > >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> > >> dst = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> > >> - dst, &dlen);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> kunmap_atomic(dst);
> > >> - zpool_unmap_handle(zswap_pool, entry->handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> > >> BUG_ON(ret);
> > >>
> > >> spin_lock(&tree->lock);
> > >> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> > >> zswap_trees[type] = NULL;
> > >> }
> > >>
> > >> -static struct zpool_ops zswap_zpool_ops = {
> > >> - .evict = zswap_writeback_entry
> > >> -};
> > >> -
> > >> static void zswap_frontswap_init(unsigned type)
> > >> {
> > >> struct zswap_tree *tree;
> > >> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> > >> **********************************/
> > >> static int __init init_zswap(void)
> > >> {
> > >> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> > >> + struct zswap_pool *pool;
> > >>
> > >> - pr_info("loading zswap\n");
> > >> -
> > >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> > >> - &zswap_zpool_ops);
> > >> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> > >> - pr_info("%s zpool not available\n", zswap_zpool_type);
> > >> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> > >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> > >> - &zswap_zpool_ops);
> > >> - }
> > >> - if (!zswap_pool) {
> > >> - pr_err("%s zpool not available\n", zswap_zpool_type);
> > >> - pr_err("zpool creation failed\n");
> > >> - goto error;
> > >> - }
> > >> - pr_info("using %s pool\n", zswap_zpool_type);
> > >> + pr_info("loading\n");
> > >>
> > >> if (zswap_entry_cache_create()) {
> > >> pr_err("entry cache creation failed\n");
> > >> - goto cachefail;
> > >> + goto cache_fail;
> > >> }
> > >> - if (zswap_comp_init()) {
> > >> - pr_err("compressor initialization failed\n");
> > >> - goto compfail;
> > >> +
> > >> + if (zswap_cpu_dstmem_init()) {
> > >> + pr_err("dstmem alloc failed\n");
> > >> + goto dstmem_fail;
> > >> }
> > >> - if (zswap_cpu_init()) {
> > >> - pr_err("per-cpu initialization failed\n");
> > >> - goto pcpufail;
> > >> +
> > >> + pool = __zswap_pool_create_fallback();
> > >> + if (!pool) {
> > >> + pr_err("pool creation failed\n");
> > >> + goto pool_fail;
> > >> }
> > >> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> > >> + zpool_get_type(pool->zpool));
> > >> +
> > >> + list_add(&pool->list, &zswap_pools);
> > >>
> > >> frontswap_register_ops(&zswap_frontswap_ops);
> > >> if (zswap_debugfs_init())
> > >> pr_warn("debugfs initialization failed\n");
> > >> return 0;
> > >> -pcpufail:
> > >> - zswap_comp_exit();
> > >> -compfail:
> > >> +
> > >> +pool_fail:
> > >> + zswap_cpu_dstmem_destroy();
> > >> +dstmem_fail:
> > >> zswap_entry_cache_destroy();
> > >> -cachefail:
> > >> - zpool_destroy_pool(zswap_pool);
> > >> -error:
> > >> +cache_fail:
> > >> return -ENOMEM;
> > >> }
> > >> /* must be late so crypto has time to come up */
> > >> --
> > >> 2.1.0
> > >>
--
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-17 23:13 ` Dan Streetman
@ 2015-06-25 20:22 ` Dan Streetman
-1 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-25 20:22 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Wed, Jun 17, 2015 at 7:13 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Wed, Jun 10, 2015 at 4:54 PM, Dan Streetman <ddstreet@ieee.org> wrote:
>> On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>>> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>>>> Add dynamic creation of pools. Move the static crypto compression
>>>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
>>>> the pool it's in.
>>>
>>> Seth, as far as the design, from your previous comments I assume you
>>> were thinking of maintaining separate lists of zpools and compressors?
>>> I do see how that will reduce duplication of zpools and compressors,
>>> but it also requires adding a new pointer to each zswap_entry, and
>>> increasing the amount of code to manage each list separately. And the
>>> most common case in zswap will be just a single zpool and compressor,
>>> not repeatedly changing params. What do you think?
>>
>> Any opinion on this patch? If you want, I can break it up so there's
>> a list of zpools and a list of compressors. Either the combined way
>> (this patch) or separate lists works for me, as long as the params are
>> changeable at runtime :-)
>
> You on vacation Seth? Let me know what direction you prefer for this...
So...
Andrew (or anyone else) do you have any objection to this patch? I
assume Seth is on an extended vacation; maybe you could add this to
your mmotm? If Seth prefers changes to it he still has a couple
months-ish until the next merge window. I could then send the
follow-on patches, that allow zswap params to be set at runtime. I
can resend them all as a series, if you prefer that.
I think the main issue Seth had was keeping separate lists of zpools
and compressors, instead of this patch's approach of a single list
with each element containing a zpool and compressor together. My
preference is a single list, for the reasons I gave above - mainly,
that 99+% of the time, zswap will only be using a single zpool and
compressor; users will just set the zpool and compressor immediately
after boot, instead of having to add boot parameters, and never change
them again. So keeping 2 lists only adds complexity for little to no
benefit in the common case.
>
>>
>>
>>>
>>>>
>>>> This is required by a separate patch which enables changing the
>>>> zswap zpool and compressor params at runtime.
>>>>
>>>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
>>>> ---
>>>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
>>>> 1 file changed, 408 insertions(+), 142 deletions(-)
>>>>
>>>> diff --git a/mm/zswap.c b/mm/zswap.c
>>>> index 2d5727b..fc93770 100644
>>>> --- a/mm/zswap.c
>>>> +++ b/mm/zswap.c
>>>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
>>>> static struct zpool *zswap_pool;
>>>>
>>>> /*********************************
>>>> -* compression functions
>>>> +* data structures
>>>> **********************************/
>>>> -/* per-cpu compression transforms */
>>>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>>>>
>>>> -enum comp_op {
>>>> - ZSWAP_COMPOP_COMPRESS,
>>>> - ZSWAP_COMPOP_DECOMPRESS
>>>> +struct zswap_pool {
>>>> + struct zpool *zpool;
>>>> + struct kref kref;
>>>> + struct list_head list;
>>>> + struct rcu_head rcu_head;
>>>> + struct notifier_block notifier;
>>>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
>>>> + struct crypto_comp * __percpu *tfm;
>>>> };
>>>>
>>>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
>>>> - u8 *dst, unsigned int *dlen)
>>>> -{
>>>> - struct crypto_comp *tfm;
>>>> - int ret;
>>>> -
>>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
>>>> - switch (op) {
>>>> - case ZSWAP_COMPOP_COMPRESS:
>>>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
>>>> - break;
>>>> - case ZSWAP_COMPOP_DECOMPRESS:
>>>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
>>>> - break;
>>>> - default:
>>>> - ret = -EINVAL;
>>>> - }
>>>> -
>>>> - put_cpu();
>>>> - return ret;
>>>> -}
>>>> -
>>>> -static int __init zswap_comp_init(void)
>>>> -{
>>>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>>> - pr_info("%s compressor not available\n", zswap_compressor);
>>>> - /* fall back to default compressor */
>>>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
>>>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
>>>> - /* can't even load the default compressor */
>>>> - return -ENODEV;
>>>> - }
>>>> - pr_info("using %s compressor\n", zswap_compressor);
>>>> -
>>>> - /* alloc percpu transforms */
>>>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
>>>> - if (!zswap_comp_pcpu_tfms)
>>>> - return -ENOMEM;
>>>> - return 0;
>>>> -}
>>>> -
>>>> -static void __init zswap_comp_exit(void)
>>>> -{
>>>> - /* free percpu transforms */
>>>> - free_percpu(zswap_comp_pcpu_tfms);
>>>> -}
>>>> -
>>>> -/*********************************
>>>> -* data structures
>>>> -**********************************/
>>>> /*
>>>> * struct zswap_entry
>>>> *
>>>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
>>>> * page within zswap.
>>>> *
>>>> * rbnode - links the entry into red-black tree for the appropriate swap type
>>>> + * offset - the swap offset for the entry. Index into the red-black tree.
>>>> * refcount - the number of outstanding reference to the entry. This is needed
>>>> * to protect against premature freeing of the entry by code
>>>> * concurrent calls to load, invalidate, and writeback. The lock
>>>> * for the zswap_tree structure that contains the entry must
>>>> * be held while changing the refcount. Since the lock must
>>>> * be held, there is no reason to also make refcount atomic.
>>>> - * offset - the swap offset for the entry. Index into the red-black tree.
>>>> - * handle - zpool allocation handle that stores the compressed page data
>>>> * length - the length in bytes of the compressed page data. Needed during
>>>> * decompression
>>>> + * pool - the zswap_pool the entry's data is in
>>>> + * handle - zpool allocation handle that stores the compressed page data
>>>> */
>>>> struct zswap_entry {
>>>> struct rb_node rbnode;
>>>> pgoff_t offset;
>>>> int refcount;
>>>> unsigned int length;
>>>> + struct zswap_pool *pool;
>>>> unsigned long handle;
>>>> };
>>>>
>>>> @@ -201,6 +156,44 @@ struct zswap_tree {
>>>>
>>>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>>>>
>>>> +/* RCU-protected iteration */
>>>> +static LIST_HEAD(zswap_pools);
>>>> +/* protects zswap_pools list modification */
>>>> +static DEFINE_SPINLOCK(zswap_pools_lock);
>>>> +
>>>> +/*********************************
>>>> +* helpers and fwd declarations
>>>> +**********************************/
>>>> +
>>>> +#define zswap_pool_debug(msg, p) \
>>>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
>>>> + zpool_get_type((p)->zpool))
>>>> +
>>>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
>>>> +static int zswap_pool_get(struct zswap_pool *pool);
>>>> +static void zswap_pool_put(struct zswap_pool *pool);
>>>> +
>>>> +static bool zswap_is_full(void)
>>>> +{
>>>> + return totalram_pages * zswap_max_pool_percent / 100 <
>>>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>>> +}
>>>> +
>>>> +static void zswap_update_total_size(void)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> + u64 total = 0;
>>>> +
>>>> + rcu_read_lock();
>>>> +
>>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>>> + total += zpool_get_total_size(pool->zpool);
>>>> +
>>>> + rcu_read_unlock();
>>>> +
>>>> + zswap_pool_total_size = total;
>>>> +}
>>>> +
>>>> /*********************************
>>>> * zswap entry functions
>>>> **********************************/
>>>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
>>>> */
>>>> static void zswap_free_entry(struct zswap_entry *entry)
>>>> {
>>>> - zpool_free(zswap_pool, entry->handle);
>>>> + zpool_free(entry->pool->zpool, entry->handle);
>>>> + zswap_pool_put(entry->pool);
>>>> zswap_entry_cache_free(entry);
>>>> atomic_dec(&zswap_stored_pages);
>>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>>> + zswap_update_total_size();
>>>> }
>>>>
>>>> /* caller must hold the tree lock */
>>>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
>>>> **********************************/
>>>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>>>>
>>>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
>>>> {
>>>> - struct crypto_comp *tfm;
>>>> u8 *dst;
>>>>
>>>> switch (action) {
>>>> case CPU_UP_PREPARE:
>>>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
>>>> - if (IS_ERR(tfm)) {
>>>> - pr_err("can't allocate compressor transform\n");
>>>> - return NOTIFY_BAD;
>>>> - }
>>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
>>>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
>>>> if (!dst) {
>>>> pr_err("can't allocate compressor buffer\n");
>>>> - crypto_free_comp(tfm);
>>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>>> return NOTIFY_BAD;
>>>> }
>>>> per_cpu(zswap_dstmem, cpu) = dst;
>>>> break;
>>>> case CPU_DEAD:
>>>> case CPU_UP_CANCELED:
>>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
>>>> - if (tfm) {
>>>> - crypto_free_comp(tfm);
>>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>>> - }
>>>> dst = per_cpu(zswap_dstmem, cpu);
>>>> kfree(dst);
>>>> per_cpu(zswap_dstmem, cpu) = NULL;
>>>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>>> return NOTIFY_OK;
>>>> }
>>>>
>>>> -static int zswap_cpu_notifier(struct notifier_block *nb,
>>>> - unsigned long action, void *pcpu)
>>>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
>>>> + unsigned long action, void *pcpu)
>>>> {
>>>> - unsigned long cpu = (unsigned long)pcpu;
>>>> - return __zswap_cpu_notifier(action, cpu);
>>>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
>>>> }
>>>>
>>>> -static struct notifier_block zswap_cpu_notifier_block = {
>>>> - .notifier_call = zswap_cpu_notifier
>>>> +static struct notifier_block zswap_dstmem_notifier = {
>>>> + .notifier_call = zswap_cpu_dstmem_notifier,
>>>> };
>>>>
>>>> -static int __init zswap_cpu_init(void)
>>>> +static int __init zswap_cpu_dstmem_init(void)
>>>> {
>>>> unsigned long cpu;
>>>>
>>>> cpu_notifier_register_begin();
>>>> for_each_online_cpu(cpu)
>>>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
>>>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
>>>> + NOTIFY_BAD)
>>>> goto cleanup;
>>>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
>>>> + __register_cpu_notifier(&zswap_dstmem_notifier);
>>>> cpu_notifier_register_done();
>>>> return 0;
>>>>
>>>> cleanup:
>>>> for_each_online_cpu(cpu)
>>>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
>>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>>> cpu_notifier_register_done();
>>>> return -ENOMEM;
>>>> }
>>>>
>>>> +static void zswap_cpu_dstmem_destroy(void)
>>>> +{
>>>> + unsigned long cpu;
>>>> +
>>>> + cpu_notifier_register_begin();
>>>> + for_each_online_cpu(cpu)
>>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
>>>> + cpu_notifier_register_done();
>>>> +}
>>>> +
>>>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
>>>> + unsigned long action, unsigned long cpu)
>>>> +{
>>>> + struct crypto_comp *tfm;
>>>> +
>>>> + switch (action) {
>>>> + case CPU_UP_PREPARE:
>>>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
>>>> + break;
>>>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
>>>> + if (IS_ERR_OR_NULL(tfm)) {
>>>> + pr_err("could not alloc crypto comp %s : %ld\n",
>>>> + pool->tfm_name, PTR_ERR(tfm));
>>>> + return NOTIFY_BAD;
>>>> + }
>>>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
>>>> + break;
>>>> + case CPU_DEAD:
>>>> + case CPU_UP_CANCELED:
>>>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
>>>> + if (!IS_ERR_OR_NULL(tfm))
>>>> + crypto_free_comp(tfm);
>>>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
>>>> + break;
>>>> + default:
>>>> + break;
>>>> + }
>>>> + return NOTIFY_OK;
>>>> +}
>>>> +
>>>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
>>>> + unsigned long action, void *pcpu)
>>>> +{
>>>> + unsigned long cpu = (unsigned long)pcpu;
>>>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
>>>> +
>>>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
>>>> +}
>>>> +
>>>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
>>>> +{
>>>> + unsigned long cpu;
>>>> +
>>>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
>>>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
>>>> +
>>>> + cpu_notifier_register_begin();
>>>> + for_each_online_cpu(cpu)
>>>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
>>>> + NOTIFY_BAD)
>>>> + goto cleanup;
>>>> + __register_cpu_notifier(&pool->notifier);
>>>> + cpu_notifier_register_done();
>>>> + return 0;
>>>> +
>>>> +cleanup:
>>>> + for_each_online_cpu(cpu)
>>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>>> + cpu_notifier_register_done();
>>>> + return -ENOMEM;
>>>> +}
>>>> +
>>>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
>>>> +{
>>>> + unsigned long cpu;
>>>> +
>>>> + cpu_notifier_register_begin();
>>>> + for_each_online_cpu(cpu)
>>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>>> + __unregister_cpu_notifier(&pool->notifier);
>>>> + cpu_notifier_register_done();
>>>> +}
>>>> +
>>>> /*********************************
>>>> -* helpers
>>>> +* pool functions
>>>> **********************************/
>>>> -static bool zswap_is_full(void)
>>>> +
>>>> +static struct zswap_pool *__zswap_pool_current(void)
>>>> {
>>>> - return totalram_pages * zswap_max_pool_percent / 100 <
>>>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
>>>> + WARN_ON(!pool);
>>>> +
>>>> + return pool;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_current(void)
>>>> +{
>>>> + assert_spin_locked(&zswap_pools_lock);
>>>> +
>>>> + return __zswap_pool_current();
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_current_get(void)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + rcu_read_lock();
>>>> +
>>>> + pool = __zswap_pool_current();
>>>> + if (!pool || !zswap_pool_get(pool))
>>>> + pool = NULL;
>>>> +
>>>> + rcu_read_unlock();
>>>> +
>>>> + return pool;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_last_get(void)
>>>> +{
>>>> + struct zswap_pool *pool, *last = NULL;
>>>> +
>>>> + rcu_read_lock();
>>>> +
>>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>>> + last = pool;
>>>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
>>>> + last = NULL;
>>>> +
>>>> + rcu_read_unlock();
>>>> +
>>>> + return last;
>>>> +}
>>>> +
>>>> +static struct zpool_ops zswap_zpool_ops = {
>>>> + .evict = zswap_writeback_entry
>>>> +};
>>>> +
>>>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + assert_spin_locked(&zswap_pools_lock);
>>>> +
>>>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
>>>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
>>>> + continue;
>>>> + if (strncmp(zpool_get_type(pool->zpool), type,
>>>> + sizeof(zswap_zpool_type)))
>>>> + continue;
>>>> + /* if we can't get it, it's about to be destroyed */
>>>> + if (!zswap_pool_get(pool))
>>>> + continue;
>>>> + return pool;
>>>> + }
>>>> +
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>>> +
>>>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
>>>> + if (!pool) {
>>>> + pr_err("pool alloc failed\n");
>>>> + return NULL;
>>>> + }
>>>> +
>>>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
>>>> + if (!pool->zpool) {
>>>> + pr_err("%s zpool not available\n", type);
>>>> + goto error;
>>>> + }
>>>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
>>>> +
>>>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
>>>> + pool->tfm = alloc_percpu(struct crypto_comp *);
>>>> + if (!pool->tfm) {
>>>> + pr_err("percpu alloc failed\n");
>>>> + goto error;
>>>> + }
>>>> +
>>>> + if (zswap_cpu_comp_init(pool))
>>>> + goto error;
>>>> + pr_debug("using %s compressor\n", pool->tfm_name);
>>>> +
>>>> + /* being the current pool takes 1 ref; this func expects the
>>>> + * caller to always add the new pool as the current pool
>>>> + */
>>>> + kref_init(&pool->kref);
>>>> + INIT_LIST_HEAD(&pool->list);
>>>> +
>>>> + zswap_pool_debug("created", pool);
>>>> +
>>>> + return pool;
>>>> +
>>>> +error:
>>>> + free_percpu(pool->tfm);
>>>> + if (pool->zpool)
>>>> + zpool_destroy_pool(pool->zpool);
>>>> + kfree(pool);
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
>>>> +{
>>>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>>> + pr_err("compressor %s not available, using default %s\n",
>>>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
>>>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
>>>> + sizeof(zswap_compressor));
>>>> + }
>>>> + if (!zpool_has_pool(zswap_zpool_type)) {
>>>> + pr_err("zpool %s not available, using default %s\n",
>>>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
>>>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
>>>> + sizeof(zswap_zpool_type));
>>>> + }
>>>> +
>>>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
>>>> +}
>>>> +
>>>> +static void zswap_pool_destroy(struct zswap_pool *pool)
>>>> +{
>>>> + zswap_pool_debug("destroying", pool);
>>>> +
>>>> + zswap_cpu_comp_destroy(pool);
>>>> + free_percpu(pool->tfm);
>>>> + zpool_destroy_pool(pool->zpool);
>>>> + kfree(pool);
>>>> +}
>>>> +
>>>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
>>>> +{
>>>> + return kref_get_unless_zero(&pool->kref);
>>>> +}
>>>> +
>>>> +static void __zswap_pool_release(struct rcu_head *head)
>>>> +{
>>>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
>>>> +
>>>> + /* nobody should have been able to get a kref... */
>>>> + WARN_ON(kref_get_unless_zero(&pool->kref));
>>>> +
>>>> + /* pool is now off zswap_pools list and has no references. */
>>>> + zswap_pool_destroy(pool);
>>>> +}
>>>> +
>>>> +static void __zswap_pool_empty(struct kref *kref)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + pool = container_of(kref, typeof(*pool), kref);
>>>> +
>>>> + spin_lock(&zswap_pools_lock);
>>>> +
>>>> + WARN_ON(pool == zswap_pool_current());
>>>> +
>>>> + list_del_rcu(&pool->list);
>>>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
>>>> +
>>>> + spin_unlock(&zswap_pools_lock);
>>>> +}
>>>> +
>>>> +static void zswap_pool_put(struct zswap_pool *pool)
>>>> +{
>>>> + kref_put(&pool->kref, __zswap_pool_empty);
>>>> +}
>>>> +
>>>> }
>>>>
>>>> /*********************************
>>>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>>> pgoff_t offset;
>>>> struct zswap_entry *entry;
>>>> struct page *page;
>>>> + struct crypto_comp *tfm;
>>>> u8 *src, *dst;
>>>> unsigned int dlen;
>>>> int ret;
>>>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
>>>> /* decompress */
>>>> dlen = PAGE_SIZE;
>>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>>> dst = kmap_atomic(page);
>>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
>>>> - entry->length, dst, &dlen);
>>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>>> + ret = crypto_comp_decompress(tfm, src, entry->length,
>>>> + dst, &dlen);
>>>> + put_cpu_ptr(entry->pool->tfm);
>>>> kunmap_atomic(dst);
>>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>>> BUG_ON(ret);
>>>> BUG_ON(dlen != PAGE_SIZE);
>>>>
>>>> @@ -633,6 +882,22 @@ end:
>>>> return ret;
>>>> }
>>>>
>>>> +static int zswap_shrink(void)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> + int ret;
>>>> +
>>>> + pool = zswap_pool_last_get();
>>>> + if (!pool)
>>>> + return -ENOENT;
>>>> +
>>>> + ret = zpool_shrink(pool->zpool, 1, NULL);
>>>> +
>>>> + zswap_pool_put(pool);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> /*********************************
>>>> * frontswap hooks
>>>> **********************************/
>>>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>> {
>>>> struct zswap_tree *tree = zswap_trees[type];
>>>> struct zswap_entry *entry, *dupentry;
>>>> + struct crypto_comp *tfm;
>>>> int ret;
>>>> unsigned int dlen = PAGE_SIZE, len;
>>>> unsigned long handle;
>>>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>> /* reclaim space if needed */
>>>> if (zswap_is_full()) {
>>>> zswap_pool_limit_hit++;
>>>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
>>>> + if (zswap_shrink()) {
>>>> zswap_reject_reclaim_fail++;
>>>> ret = -ENOMEM;
>>>> goto reject;
>>>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>> goto reject;
>>>> }
>>>>
>>>> + /* if entry is successfully added, it keeps the reference */
>>>> + entry->pool = zswap_pool_current_get();
>>>> + if (!entry->pool) {
>>>> + ret = -EINVAL;
>>>> + goto freepage;
>>>> + }
>>>> +
>>>> /* compress */
>>>> dst = get_cpu_var(zswap_dstmem);
>>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>>> src = kmap_atomic(page);
>>>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
>>>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
>>>> kunmap_atomic(src);
>>>> + put_cpu_ptr(entry->pool->tfm);
>>>> if (ret) {
>>>> ret = -EINVAL;
>>>> - goto freepage;
>>>> + goto put_dstmem;
>>>> }
>>>>
>>>> /* store */
>>>> len = dlen + sizeof(struct zswap_header);
>>>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
>>>> - &handle);
>>>> + ret = zpool_malloc(entry->pool->zpool, len,
>>>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
>>>> if (ret == -ENOSPC) {
>>>> zswap_reject_compress_poor++;
>>>> - goto freepage;
>>>> + goto put_dstmem;
>>>> }
>>>> if (ret) {
>>>> zswap_reject_alloc_fail++;
>>>> - goto freepage;
>>>> + goto put_dstmem;
>>>> }
>>>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
>>>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
>>>> zhdr->swpentry = swp_entry(type, offset);
>>>> buf = (u8 *)(zhdr + 1);
>>>> memcpy(buf, dst, dlen);
>>>> - zpool_unmap_handle(zswap_pool, handle);
>>>> + zpool_unmap_handle(entry->pool->zpool, handle);
>>>> put_cpu_var(zswap_dstmem);
>>>>
>>>> /* populate entry */
>>>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>>
>>>> /* update stats */
>>>> atomic_inc(&zswap_stored_pages);
>>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>>> + zswap_update_total_size();
>>>>
>>>> return 0;
>>>>
>>>> -freepage:
>>>> +put_dstmem:
>>>> put_cpu_var(zswap_dstmem);
>>>> + zswap_pool_put(entry->pool);
>>>> +freepage:
>>>> zswap_entry_cache_free(entry);
>>>> reject:
>>>> return ret;
>>>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>>> {
>>>> struct zswap_tree *tree = zswap_trees[type];
>>>> struct zswap_entry *entry;
>>>> + struct crypto_comp *tfm;
>>>> u8 *src, *dst;
>>>> unsigned int dlen;
>>>> int ret;
>>>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>>>
>>>> /* decompress */
>>>> dlen = PAGE_SIZE;
>>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>>> dst = kmap_atomic(page);
>>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
>>>> - dst, &dlen);
>>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
>>>> + put_cpu_ptr(entry->pool->tfm);
>>>> kunmap_atomic(dst);
>>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>>> BUG_ON(ret);
>>>>
>>>> spin_lock(&tree->lock);
>>>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
>>>> zswap_trees[type] = NULL;
>>>> }
>>>>
>>>> -static struct zpool_ops zswap_zpool_ops = {
>>>> - .evict = zswap_writeback_entry
>>>> -};
>>>> -
>>>> static void zswap_frontswap_init(unsigned type)
>>>> {
>>>> struct zswap_tree *tree;
>>>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
>>>> **********************************/
>>>> static int __init init_zswap(void)
>>>> {
>>>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>>> + struct zswap_pool *pool;
>>>>
>>>> - pr_info("loading zswap\n");
>>>> -
>>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>>> - &zswap_zpool_ops);
>>>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
>>>> - pr_info("%s zpool not available\n", zswap_zpool_type);
>>>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
>>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>>> - &zswap_zpool_ops);
>>>> - }
>>>> - if (!zswap_pool) {
>>>> - pr_err("%s zpool not available\n", zswap_zpool_type);
>>>> - pr_err("zpool creation failed\n");
>>>> - goto error;
>>>> - }
>>>> - pr_info("using %s pool\n", zswap_zpool_type);
>>>> + pr_info("loading\n");
>>>>
>>>> if (zswap_entry_cache_create()) {
>>>> pr_err("entry cache creation failed\n");
>>>> - goto cachefail;
>>>> + goto cache_fail;
>>>> }
>>>> - if (zswap_comp_init()) {
>>>> - pr_err("compressor initialization failed\n");
>>>> - goto compfail;
>>>> +
>>>> + if (zswap_cpu_dstmem_init()) {
>>>> + pr_err("dstmem alloc failed\n");
>>>> + goto dstmem_fail;
>>>> }
>>>> - if (zswap_cpu_init()) {
>>>> - pr_err("per-cpu initialization failed\n");
>>>> - goto pcpufail;
>>>> +
>>>> + pool = __zswap_pool_create_fallback();
>>>> + if (!pool) {
>>>> + pr_err("pool creation failed\n");
>>>> + goto pool_fail;
>>>> }
>>>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
>>>> + zpool_get_type(pool->zpool));
>>>> +
>>>> + list_add(&pool->list, &zswap_pools);
>>>>
>>>> frontswap_register_ops(&zswap_frontswap_ops);
>>>> if (zswap_debugfs_init())
>>>> pr_warn("debugfs initialization failed\n");
>>>> return 0;
>>>> -pcpufail:
>>>> - zswap_comp_exit();
>>>> -compfail:
>>>> +
>>>> +pool_fail:
>>>> + zswap_cpu_dstmem_destroy();
>>>> +dstmem_fail:
>>>> zswap_entry_cache_destroy();
>>>> -cachefail:
>>>> - zpool_destroy_pool(zswap_pool);
>>>> -error:
>>>> +cache_fail:
>>>> return -ENOMEM;
>>>> }
>>>> /* must be late so crypto has time to come up */
>>>> --
>>>> 2.1.0
>>>>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-25 20:22 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-25 20:22 UTC (permalink / raw)
To: Seth Jennings, Andrew Morton; +Cc: Linux-MM, linux-kernel, Dan Streetman
On Wed, Jun 17, 2015 at 7:13 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Wed, Jun 10, 2015 at 4:54 PM, Dan Streetman <ddstreet@ieee.org> wrote:
>> On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>>> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
>>>> Add dynamic creation of pools. Move the static crypto compression
>>>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
>>>> the pool it's in.
>>>
>>> Seth, as far as the design, from your previous comments I assume you
>>> were thinking of maintaining separate lists of zpools and compressors?
>>> I do see how that will reduce duplication of zpools and compressors,
>>> but it also requires adding a new pointer to each zswap_entry, and
>>> increasing the amount of code to manage each list separately. And the
>>> most common case in zswap will be just a single zpool and compressor,
>>> not repeatedly changing params. What do you think?
>>
>> Any opinion on this patch? If you want, I can break it up so there's
>> a list of zpools and a list of compressors. Either the combined way
>> (this patch) or separate lists works for me, as long as the params are
>> changeable at runtime :-)
>
> You on vacation Seth? Let me know what direction you prefer for this...
So...
Andrew (or anyone else) do you have any objection to this patch? I
assume Seth is on an extended vacation; maybe you could add this to
your mmotm? If Seth prefers changes to it he still has a couple
months-ish until the next merge window. I could then send the
follow-on patches, that allow zswap params to be set at runtime. I
can resend them all as a series, if you prefer that.
I think the main issue Seth had was keeping separate lists of zpools
and compressors, instead of this patch's approach of a single list
with each element containing a zpool and compressor together. My
preference is a single list, for the reasons I gave above - mainly,
that 99+% of the time, zswap will only be using a single zpool and
compressor; users will just set the zpool and compressor immediately
after boot, instead of having to add boot parameters, and never change
them again. So keeping 2 lists only adds complexity for little to no
benefit in the common case.
>
>>
>>
>>>
>>>>
>>>> This is required by a separate patch which enables changing the
>>>> zswap zpool and compressor params at runtime.
>>>>
>>>> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
>>>> ---
>>>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
>>>> 1 file changed, 408 insertions(+), 142 deletions(-)
>>>>
>>>> diff --git a/mm/zswap.c b/mm/zswap.c
>>>> index 2d5727b..fc93770 100644
>>>> --- a/mm/zswap.c
>>>> +++ b/mm/zswap.c
>>>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
>>>> static struct zpool *zswap_pool;
>>>>
>>>> /*********************************
>>>> -* compression functions
>>>> +* data structures
>>>> **********************************/
>>>> -/* per-cpu compression transforms */
>>>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
>>>>
>>>> -enum comp_op {
>>>> - ZSWAP_COMPOP_COMPRESS,
>>>> - ZSWAP_COMPOP_DECOMPRESS
>>>> +struct zswap_pool {
>>>> + struct zpool *zpool;
>>>> + struct kref kref;
>>>> + struct list_head list;
>>>> + struct rcu_head rcu_head;
>>>> + struct notifier_block notifier;
>>>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
>>>> + struct crypto_comp * __percpu *tfm;
>>>> };
>>>>
>>>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
>>>> - u8 *dst, unsigned int *dlen)
>>>> -{
>>>> - struct crypto_comp *tfm;
>>>> - int ret;
>>>> -
>>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
>>>> - switch (op) {
>>>> - case ZSWAP_COMPOP_COMPRESS:
>>>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
>>>> - break;
>>>> - case ZSWAP_COMPOP_DECOMPRESS:
>>>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
>>>> - break;
>>>> - default:
>>>> - ret = -EINVAL;
>>>> - }
>>>> -
>>>> - put_cpu();
>>>> - return ret;
>>>> -}
>>>> -
>>>> -static int __init zswap_comp_init(void)
>>>> -{
>>>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>>> - pr_info("%s compressor not available\n", zswap_compressor);
>>>> - /* fall back to default compressor */
>>>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
>>>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
>>>> - /* can't even load the default compressor */
>>>> - return -ENODEV;
>>>> - }
>>>> - pr_info("using %s compressor\n", zswap_compressor);
>>>> -
>>>> - /* alloc percpu transforms */
>>>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
>>>> - if (!zswap_comp_pcpu_tfms)
>>>> - return -ENOMEM;
>>>> - return 0;
>>>> -}
>>>> -
>>>> -static void __init zswap_comp_exit(void)
>>>> -{
>>>> - /* free percpu transforms */
>>>> - free_percpu(zswap_comp_pcpu_tfms);
>>>> -}
>>>> -
>>>> -/*********************************
>>>> -* data structures
>>>> -**********************************/
>>>> /*
>>>> * struct zswap_entry
>>>> *
>>>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
>>>> * page within zswap.
>>>> *
>>>> * rbnode - links the entry into red-black tree for the appropriate swap type
>>>> + * offset - the swap offset for the entry. Index into the red-black tree.
>>>> * refcount - the number of outstanding reference to the entry. This is needed
>>>> * to protect against premature freeing of the entry by code
>>>> * concurrent calls to load, invalidate, and writeback. The lock
>>>> * for the zswap_tree structure that contains the entry must
>>>> * be held while changing the refcount. Since the lock must
>>>> * be held, there is no reason to also make refcount atomic.
>>>> - * offset - the swap offset for the entry. Index into the red-black tree.
>>>> - * handle - zpool allocation handle that stores the compressed page data
>>>> * length - the length in bytes of the compressed page data. Needed during
>>>> * decompression
>>>> + * pool - the zswap_pool the entry's data is in
>>>> + * handle - zpool allocation handle that stores the compressed page data
>>>> */
>>>> struct zswap_entry {
>>>> struct rb_node rbnode;
>>>> pgoff_t offset;
>>>> int refcount;
>>>> unsigned int length;
>>>> + struct zswap_pool *pool;
>>>> unsigned long handle;
>>>> };
>>>>
>>>> @@ -201,6 +156,44 @@ struct zswap_tree {
>>>>
>>>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
>>>>
>>>> +/* RCU-protected iteration */
>>>> +static LIST_HEAD(zswap_pools);
>>>> +/* protects zswap_pools list modification */
>>>> +static DEFINE_SPINLOCK(zswap_pools_lock);
>>>> +
>>>> +/*********************************
>>>> +* helpers and fwd declarations
>>>> +**********************************/
>>>> +
>>>> +#define zswap_pool_debug(msg, p) \
>>>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
>>>> + zpool_get_type((p)->zpool))
>>>> +
>>>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
>>>> +static int zswap_pool_get(struct zswap_pool *pool);
>>>> +static void zswap_pool_put(struct zswap_pool *pool);
>>>> +
>>>> +static bool zswap_is_full(void)
>>>> +{
>>>> + return totalram_pages * zswap_max_pool_percent / 100 <
>>>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>>> +}
>>>> +
>>>> +static void zswap_update_total_size(void)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> + u64 total = 0;
>>>> +
>>>> + rcu_read_lock();
>>>> +
>>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>>> + total += zpool_get_total_size(pool->zpool);
>>>> +
>>>> + rcu_read_unlock();
>>>> +
>>>> + zswap_pool_total_size = total;
>>>> +}
>>>> +
>>>> /*********************************
>>>> * zswap entry functions
>>>> **********************************/
>>>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
>>>> */
>>>> static void zswap_free_entry(struct zswap_entry *entry)
>>>> {
>>>> - zpool_free(zswap_pool, entry->handle);
>>>> + zpool_free(entry->pool->zpool, entry->handle);
>>>> + zswap_pool_put(entry->pool);
>>>> zswap_entry_cache_free(entry);
>>>> atomic_dec(&zswap_stored_pages);
>>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>>> + zswap_update_total_size();
>>>> }
>>>>
>>>> /* caller must hold the tree lock */
>>>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
>>>> **********************************/
>>>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
>>>>
>>>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
>>>> {
>>>> - struct crypto_comp *tfm;
>>>> u8 *dst;
>>>>
>>>> switch (action) {
>>>> case CPU_UP_PREPARE:
>>>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
>>>> - if (IS_ERR(tfm)) {
>>>> - pr_err("can't allocate compressor transform\n");
>>>> - return NOTIFY_BAD;
>>>> - }
>>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
>>>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
>>>> if (!dst) {
>>>> pr_err("can't allocate compressor buffer\n");
>>>> - crypto_free_comp(tfm);
>>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>>> return NOTIFY_BAD;
>>>> }
>>>> per_cpu(zswap_dstmem, cpu) = dst;
>>>> break;
>>>> case CPU_DEAD:
>>>> case CPU_UP_CANCELED:
>>>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
>>>> - if (tfm) {
>>>> - crypto_free_comp(tfm);
>>>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
>>>> - }
>>>> dst = per_cpu(zswap_dstmem, cpu);
>>>> kfree(dst);
>>>> per_cpu(zswap_dstmem, cpu) = NULL;
>>>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
>>>> return NOTIFY_OK;
>>>> }
>>>>
>>>> -static int zswap_cpu_notifier(struct notifier_block *nb,
>>>> - unsigned long action, void *pcpu)
>>>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
>>>> + unsigned long action, void *pcpu)
>>>> {
>>>> - unsigned long cpu = (unsigned long)pcpu;
>>>> - return __zswap_cpu_notifier(action, cpu);
>>>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
>>>> }
>>>>
>>>> -static struct notifier_block zswap_cpu_notifier_block = {
>>>> - .notifier_call = zswap_cpu_notifier
>>>> +static struct notifier_block zswap_dstmem_notifier = {
>>>> + .notifier_call = zswap_cpu_dstmem_notifier,
>>>> };
>>>>
>>>> -static int __init zswap_cpu_init(void)
>>>> +static int __init zswap_cpu_dstmem_init(void)
>>>> {
>>>> unsigned long cpu;
>>>>
>>>> cpu_notifier_register_begin();
>>>> for_each_online_cpu(cpu)
>>>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
>>>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
>>>> + NOTIFY_BAD)
>>>> goto cleanup;
>>>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
>>>> + __register_cpu_notifier(&zswap_dstmem_notifier);
>>>> cpu_notifier_register_done();
>>>> return 0;
>>>>
>>>> cleanup:
>>>> for_each_online_cpu(cpu)
>>>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
>>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>>> cpu_notifier_register_done();
>>>> return -ENOMEM;
>>>> }
>>>>
>>>> +static void zswap_cpu_dstmem_destroy(void)
>>>> +{
>>>> + unsigned long cpu;
>>>> +
>>>> + cpu_notifier_register_begin();
>>>> + for_each_online_cpu(cpu)
>>>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
>>>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
>>>> + cpu_notifier_register_done();
>>>> +}
>>>> +
>>>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
>>>> + unsigned long action, unsigned long cpu)
>>>> +{
>>>> + struct crypto_comp *tfm;
>>>> +
>>>> + switch (action) {
>>>> + case CPU_UP_PREPARE:
>>>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
>>>> + break;
>>>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
>>>> + if (IS_ERR_OR_NULL(tfm)) {
>>>> + pr_err("could not alloc crypto comp %s : %ld\n",
>>>> + pool->tfm_name, PTR_ERR(tfm));
>>>> + return NOTIFY_BAD;
>>>> + }
>>>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
>>>> + break;
>>>> + case CPU_DEAD:
>>>> + case CPU_UP_CANCELED:
>>>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
>>>> + if (!IS_ERR_OR_NULL(tfm))
>>>> + crypto_free_comp(tfm);
>>>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
>>>> + break;
>>>> + default:
>>>> + break;
>>>> + }
>>>> + return NOTIFY_OK;
>>>> +}
>>>> +
>>>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
>>>> + unsigned long action, void *pcpu)
>>>> +{
>>>> + unsigned long cpu = (unsigned long)pcpu;
>>>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
>>>> +
>>>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
>>>> +}
>>>> +
>>>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
>>>> +{
>>>> + unsigned long cpu;
>>>> +
>>>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
>>>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
>>>> +
>>>> + cpu_notifier_register_begin();
>>>> + for_each_online_cpu(cpu)
>>>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
>>>> + NOTIFY_BAD)
>>>> + goto cleanup;
>>>> + __register_cpu_notifier(&pool->notifier);
>>>> + cpu_notifier_register_done();
>>>> + return 0;
>>>> +
>>>> +cleanup:
>>>> + for_each_online_cpu(cpu)
>>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>>> + cpu_notifier_register_done();
>>>> + return -ENOMEM;
>>>> +}
>>>> +
>>>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
>>>> +{
>>>> + unsigned long cpu;
>>>> +
>>>> + cpu_notifier_register_begin();
>>>> + for_each_online_cpu(cpu)
>>>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
>>>> + __unregister_cpu_notifier(&pool->notifier);
>>>> + cpu_notifier_register_done();
>>>> +}
>>>> +
>>>> /*********************************
>>>> -* helpers
>>>> +* pool functions
>>>> **********************************/
>>>> -static bool zswap_is_full(void)
>>>> +
>>>> +static struct zswap_pool *__zswap_pool_current(void)
>>>> {
>>>> - return totalram_pages * zswap_max_pool_percent / 100 <
>>>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
>>>> + WARN_ON(!pool);
>>>> +
>>>> + return pool;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_current(void)
>>>> +{
>>>> + assert_spin_locked(&zswap_pools_lock);
>>>> +
>>>> + return __zswap_pool_current();
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_current_get(void)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + rcu_read_lock();
>>>> +
>>>> + pool = __zswap_pool_current();
>>>> + if (!pool || !zswap_pool_get(pool))
>>>> + pool = NULL;
>>>> +
>>>> + rcu_read_unlock();
>>>> +
>>>> + return pool;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_last_get(void)
>>>> +{
>>>> + struct zswap_pool *pool, *last = NULL;
>>>> +
>>>> + rcu_read_lock();
>>>> +
>>>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
>>>> + last = pool;
>>>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
>>>> + last = NULL;
>>>> +
>>>> + rcu_read_unlock();
>>>> +
>>>> + return last;
>>>> +}
>>>> +
>>>> +static struct zpool_ops zswap_zpool_ops = {
>>>> + .evict = zswap_writeback_entry
>>>> +};
>>>> +
>>>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + assert_spin_locked(&zswap_pools_lock);
>>>> +
>>>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
>>>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
>>>> + continue;
>>>> + if (strncmp(zpool_get_type(pool->zpool), type,
>>>> + sizeof(zswap_zpool_type)))
>>>> + continue;
>>>> + /* if we can't get it, it's about to be destroyed */
>>>> + if (!zswap_pool_get(pool))
>>>> + continue;
>>>> + return pool;
>>>> + }
>>>> +
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>>> +
>>>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
>>>> + if (!pool) {
>>>> + pr_err("pool alloc failed\n");
>>>> + return NULL;
>>>> + }
>>>> +
>>>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
>>>> + if (!pool->zpool) {
>>>> + pr_err("%s zpool not available\n", type);
>>>> + goto error;
>>>> + }
>>>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
>>>> +
>>>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
>>>> + pool->tfm = alloc_percpu(struct crypto_comp *);
>>>> + if (!pool->tfm) {
>>>> + pr_err("percpu alloc failed\n");
>>>> + goto error;
>>>> + }
>>>> +
>>>> + if (zswap_cpu_comp_init(pool))
>>>> + goto error;
>>>> + pr_debug("using %s compressor\n", pool->tfm_name);
>>>> +
>>>> + /* being the current pool takes 1 ref; this func expects the
>>>> + * caller to always add the new pool as the current pool
>>>> + */
>>>> + kref_init(&pool->kref);
>>>> + INIT_LIST_HEAD(&pool->list);
>>>> +
>>>> + zswap_pool_debug("created", pool);
>>>> +
>>>> + return pool;
>>>> +
>>>> +error:
>>>> + free_percpu(pool->tfm);
>>>> + if (pool->zpool)
>>>> + zpool_destroy_pool(pool->zpool);
>>>> + kfree(pool);
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
>>>> +{
>>>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
>>>> + pr_err("compressor %s not available, using default %s\n",
>>>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
>>>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
>>>> + sizeof(zswap_compressor));
>>>> + }
>>>> + if (!zpool_has_pool(zswap_zpool_type)) {
>>>> + pr_err("zpool %s not available, using default %s\n",
>>>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
>>>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
>>>> + sizeof(zswap_zpool_type));
>>>> + }
>>>> +
>>>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
>>>> +}
>>>> +
>>>> +static void zswap_pool_destroy(struct zswap_pool *pool)
>>>> +{
>>>> + zswap_pool_debug("destroying", pool);
>>>> +
>>>> + zswap_cpu_comp_destroy(pool);
>>>> + free_percpu(pool->tfm);
>>>> + zpool_destroy_pool(pool->zpool);
>>>> + kfree(pool);
>>>> +}
>>>> +
>>>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
>>>> +{
>>>> + return kref_get_unless_zero(&pool->kref);
>>>> +}
>>>> +
>>>> +static void __zswap_pool_release(struct rcu_head *head)
>>>> +{
>>>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
>>>> +
>>>> + /* nobody should have been able to get a kref... */
>>>> + WARN_ON(kref_get_unless_zero(&pool->kref));
>>>> +
>>>> + /* pool is now off zswap_pools list and has no references. */
>>>> + zswap_pool_destroy(pool);
>>>> +}
>>>> +
>>>> +static void __zswap_pool_empty(struct kref *kref)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> +
>>>> + pool = container_of(kref, typeof(*pool), kref);
>>>> +
>>>> + spin_lock(&zswap_pools_lock);
>>>> +
>>>> + WARN_ON(pool == zswap_pool_current());
>>>> +
>>>> + list_del_rcu(&pool->list);
>>>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
>>>> +
>>>> + spin_unlock(&zswap_pools_lock);
>>>> +}
>>>> +
>>>> +static void zswap_pool_put(struct zswap_pool *pool)
>>>> +{
>>>> + kref_put(&pool->kref, __zswap_pool_empty);
>>>> +}
>>>> +
>>>> }
>>>>
>>>> /*********************************
>>>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>>> pgoff_t offset;
>>>> struct zswap_entry *entry;
>>>> struct page *page;
>>>> + struct crypto_comp *tfm;
>>>> u8 *src, *dst;
>>>> unsigned int dlen;
>>>> int ret;
>>>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
>>>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
>>>> /* decompress */
>>>> dlen = PAGE_SIZE;
>>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>>> dst = kmap_atomic(page);
>>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
>>>> - entry->length, dst, &dlen);
>>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>>> + ret = crypto_comp_decompress(tfm, src, entry->length,
>>>> + dst, &dlen);
>>>> + put_cpu_ptr(entry->pool->tfm);
>>>> kunmap_atomic(dst);
>>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>>> BUG_ON(ret);
>>>> BUG_ON(dlen != PAGE_SIZE);
>>>>
>>>> @@ -633,6 +882,22 @@ end:
>>>> return ret;
>>>> }
>>>>
>>>> +static int zswap_shrink(void)
>>>> +{
>>>> + struct zswap_pool *pool;
>>>> + int ret;
>>>> +
>>>> + pool = zswap_pool_last_get();
>>>> + if (!pool)
>>>> + return -ENOENT;
>>>> +
>>>> + ret = zpool_shrink(pool->zpool, 1, NULL);
>>>> +
>>>> + zswap_pool_put(pool);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> /*********************************
>>>> * frontswap hooks
>>>> **********************************/
>>>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>> {
>>>> struct zswap_tree *tree = zswap_trees[type];
>>>> struct zswap_entry *entry, *dupentry;
>>>> + struct crypto_comp *tfm;
>>>> int ret;
>>>> unsigned int dlen = PAGE_SIZE, len;
>>>> unsigned long handle;
>>>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>> /* reclaim space if needed */
>>>> if (zswap_is_full()) {
>>>> zswap_pool_limit_hit++;
>>>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
>>>> + if (zswap_shrink()) {
>>>> zswap_reject_reclaim_fail++;
>>>> ret = -ENOMEM;
>>>> goto reject;
>>>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>> goto reject;
>>>> }
>>>>
>>>> + /* if entry is successfully added, it keeps the reference */
>>>> + entry->pool = zswap_pool_current_get();
>>>> + if (!entry->pool) {
>>>> + ret = -EINVAL;
>>>> + goto freepage;
>>>> + }
>>>> +
>>>> /* compress */
>>>> dst = get_cpu_var(zswap_dstmem);
>>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>>> src = kmap_atomic(page);
>>>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
>>>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
>>>> kunmap_atomic(src);
>>>> + put_cpu_ptr(entry->pool->tfm);
>>>> if (ret) {
>>>> ret = -EINVAL;
>>>> - goto freepage;
>>>> + goto put_dstmem;
>>>> }
>>>>
>>>> /* store */
>>>> len = dlen + sizeof(struct zswap_header);
>>>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
>>>> - &handle);
>>>> + ret = zpool_malloc(entry->pool->zpool, len,
>>>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
>>>> if (ret == -ENOSPC) {
>>>> zswap_reject_compress_poor++;
>>>> - goto freepage;
>>>> + goto put_dstmem;
>>>> }
>>>> if (ret) {
>>>> zswap_reject_alloc_fail++;
>>>> - goto freepage;
>>>> + goto put_dstmem;
>>>> }
>>>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
>>>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
>>>> zhdr->swpentry = swp_entry(type, offset);
>>>> buf = (u8 *)(zhdr + 1);
>>>> memcpy(buf, dst, dlen);
>>>> - zpool_unmap_handle(zswap_pool, handle);
>>>> + zpool_unmap_handle(entry->pool->zpool, handle);
>>>> put_cpu_var(zswap_dstmem);
>>>>
>>>> /* populate entry */
>>>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>>>>
>>>> /* update stats */
>>>> atomic_inc(&zswap_stored_pages);
>>>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
>>>> + zswap_update_total_size();
>>>>
>>>> return 0;
>>>>
>>>> -freepage:
>>>> +put_dstmem:
>>>> put_cpu_var(zswap_dstmem);
>>>> + zswap_pool_put(entry->pool);
>>>> +freepage:
>>>> zswap_entry_cache_free(entry);
>>>> reject:
>>>> return ret;
>>>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>>> {
>>>> struct zswap_tree *tree = zswap_trees[type];
>>>> struct zswap_entry *entry;
>>>> + struct crypto_comp *tfm;
>>>> u8 *src, *dst;
>>>> unsigned int dlen;
>>>> int ret;
>>>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
>>>>
>>>> /* decompress */
>>>> dlen = PAGE_SIZE;
>>>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
>>>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
>>>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
>>>> dst = kmap_atomic(page);
>>>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
>>>> - dst, &dlen);
>>>> + tfm = *get_cpu_ptr(entry->pool->tfm);
>>>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
>>>> + put_cpu_ptr(entry->pool->tfm);
>>>> kunmap_atomic(dst);
>>>> - zpool_unmap_handle(zswap_pool, entry->handle);
>>>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
>>>> BUG_ON(ret);
>>>>
>>>> spin_lock(&tree->lock);
>>>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
>>>> zswap_trees[type] = NULL;
>>>> }
>>>>
>>>> -static struct zpool_ops zswap_zpool_ops = {
>>>> - .evict = zswap_writeback_entry
>>>> -};
>>>> -
>>>> static void zswap_frontswap_init(unsigned type)
>>>> {
>>>> struct zswap_tree *tree;
>>>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
>>>> **********************************/
>>>> static int __init init_zswap(void)
>>>> {
>>>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
>>>> + struct zswap_pool *pool;
>>>>
>>>> - pr_info("loading zswap\n");
>>>> -
>>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>>> - &zswap_zpool_ops);
>>>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
>>>> - pr_info("%s zpool not available\n", zswap_zpool_type);
>>>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
>>>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
>>>> - &zswap_zpool_ops);
>>>> - }
>>>> - if (!zswap_pool) {
>>>> - pr_err("%s zpool not available\n", zswap_zpool_type);
>>>> - pr_err("zpool creation failed\n");
>>>> - goto error;
>>>> - }
>>>> - pr_info("using %s pool\n", zswap_zpool_type);
>>>> + pr_info("loading\n");
>>>>
>>>> if (zswap_entry_cache_create()) {
>>>> pr_err("entry cache creation failed\n");
>>>> - goto cachefail;
>>>> + goto cache_fail;
>>>> }
>>>> - if (zswap_comp_init()) {
>>>> - pr_err("compressor initialization failed\n");
>>>> - goto compfail;
>>>> +
>>>> + if (zswap_cpu_dstmem_init()) {
>>>> + pr_err("dstmem alloc failed\n");
>>>> + goto dstmem_fail;
>>>> }
>>>> - if (zswap_cpu_init()) {
>>>> - pr_err("per-cpu initialization failed\n");
>>>> - goto pcpufail;
>>>> +
>>>> + pool = __zswap_pool_create_fallback();
>>>> + if (!pool) {
>>>> + pr_err("pool creation failed\n");
>>>> + goto pool_fail;
>>>> }
>>>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
>>>> + zpool_get_type(pool->zpool));
>>>> +
>>>> + list_add(&pool->list, &zswap_pools);
>>>>
>>>> frontswap_register_ops(&zswap_frontswap_ops);
>>>> if (zswap_debugfs_init())
>>>> pr_warn("debugfs initialization failed\n");
>>>> return 0;
>>>> -pcpufail:
>>>> - zswap_comp_exit();
>>>> -compfail:
>>>> +
>>>> +pool_fail:
>>>> + zswap_cpu_dstmem_destroy();
>>>> +dstmem_fail:
>>>> zswap_entry_cache_destroy();
>>>> -cachefail:
>>>> - zpool_destroy_pool(zswap_pool);
>>>> -error:
>>>> +cache_fail:
>>>> return -ENOMEM;
>>>> }
>>>> /* must be late so crypto has time to come up */
>>>> --
>>>> 2.1.0
>>>>
--
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-25 20:22 ` Dan Streetman
@ 2015-06-25 20:35 ` Andrew Morton
-1 siblings, 0 replies; 22+ messages in thread
From: Andrew Morton @ 2015-06-25 20:35 UTC (permalink / raw)
To: Dan Streetman; +Cc: Seth Jennings, Linux-MM, linux-kernel
On Thu, 25 Jun 2015 16:22:07 -0400 Dan Streetman <ddstreet@ieee.org> wrote:
> Andrew (or anyone else) do you have any objection to this patch? I
> assume Seth is on an extended vacation; maybe you could add this to
> your mmotm? If Seth prefers changes to it he still has a couple
> months-ish until the next merge window. I could then send the
> follow-on patches, that allow zswap params to be set at runtime. I
> can resend them all as a series, if you prefer that.
I'll take a look once the merge window mayhem settles down. But it
never hurts to do a refresh/retest/resend.
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-25 20:35 ` Andrew Morton
0 siblings, 0 replies; 22+ messages in thread
From: Andrew Morton @ 2015-06-25 20:35 UTC (permalink / raw)
To: Dan Streetman; +Cc: Seth Jennings, Linux-MM, linux-kernel
On Thu, 25 Jun 2015 16:22:07 -0400 Dan Streetman <ddstreet@ieee.org> wrote:
> Andrew (or anyone else) do you have any objection to this patch? I
> assume Seth is on an extended vacation; maybe you could add this to
> your mmotm? If Seth prefers changes to it he still has a couple
> months-ish until the next merge window. I could then send the
> follow-on patches, that allow zswap params to be set at runtime. I
> can resend them all as a series, if you prefer that.
I'll take a look once the merge window mayhem settles down. But it
never hurts to do a refresh/retest/resend.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-25 20:35 ` Andrew Morton
@ 2015-06-25 20:37 ` Dan Streetman
-1 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-25 20:37 UTC (permalink / raw)
To: Andrew Morton; +Cc: Seth Jennings, Linux-MM, linux-kernel
On Thu, Jun 25, 2015 at 4:35 PM, Andrew Morton
<akpm@linux-foundation.org> wrote:
> On Thu, 25 Jun 2015 16:22:07 -0400 Dan Streetman <ddstreet@ieee.org> wrote:
>
>> Andrew (or anyone else) do you have any objection to this patch? I
>> assume Seth is on an extended vacation; maybe you could add this to
>> your mmotm? If Seth prefers changes to it he still has a couple
>> months-ish until the next merge window. I could then send the
>> follow-on patches, that allow zswap params to be set at runtime. I
>> can resend them all as a series, if you prefer that.
>
> I'll take a look once the merge window mayhem settles down. But it
> never hurts to do a refresh/retest/resend.
Sure, let me rebase the whole thing onto the latest upstream, and I'll
resend the series.
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-06-25 20:37 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-06-25 20:37 UTC (permalink / raw)
To: Andrew Morton; +Cc: Seth Jennings, Linux-MM, linux-kernel
On Thu, Jun 25, 2015 at 4:35 PM, Andrew Morton
<akpm@linux-foundation.org> wrote:
> On Thu, 25 Jun 2015 16:22:07 -0400 Dan Streetman <ddstreet@ieee.org> wrote:
>
>> Andrew (or anyone else) do you have any objection to this patch? I
>> assume Seth is on an extended vacation; maybe you could add this to
>> your mmotm? If Seth prefers changes to it he still has a couple
>> months-ish until the next merge window. I could then send the
>> follow-on patches, that allow zswap params to be set at runtime. I
>> can resend them all as a series, if you prefer that.
>
> I'll take a look once the merge window mayhem settles down. But it
> never hurts to do a refresh/retest/resend.
Sure, let me rebase the whole thing onto the latest upstream, and I'll
resend the series.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
2015-06-25 20:37 ` Dan Streetman
@ 2015-07-15 22:18 ` Dan Streetman
-1 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-07-15 22:18 UTC (permalink / raw)
To: Andrew Morton; +Cc: Seth Jennings, Linux-MM, linux-kernel
On Thu, Jun 25, 2015 at 4:37 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Thu, Jun 25, 2015 at 4:35 PM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
>> On Thu, 25 Jun 2015 16:22:07 -0400 Dan Streetman <ddstreet@ieee.org> wrote:
>>
>>> Andrew (or anyone else) do you have any objection to this patch? I
>>> assume Seth is on an extended vacation; maybe you could add this to
>>> your mmotm? If Seth prefers changes to it he still has a couple
>>> months-ish until the next merge window. I could then send the
>>> follow-on patches, that allow zswap params to be set at runtime. I
>>> can resend them all as a series, if you prefer that.
>>
>> I'll take a look once the merge window mayhem settles down. But it
>> never hurts to do a refresh/retest/resend.
>
> Sure, let me rebase the whole thing onto the latest upstream, and I'll
> resend the series.
Seth,
I don't know what happened, but I never got any of your replies (in my
gmail account), although I see them in the list archives :(
Just to reset everything, I'll rebase the patches and resend them, and
we can continue the discussion. Sorry for the confusion!
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH] zswap: dynamic pool creation
@ 2015-07-15 22:18 ` Dan Streetman
0 siblings, 0 replies; 22+ messages in thread
From: Dan Streetman @ 2015-07-15 22:18 UTC (permalink / raw)
To: Andrew Morton; +Cc: Seth Jennings, Linux-MM, linux-kernel
On Thu, Jun 25, 2015 at 4:37 PM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Thu, Jun 25, 2015 at 4:35 PM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
>> On Thu, 25 Jun 2015 16:22:07 -0400 Dan Streetman <ddstreet@ieee.org> wrote:
>>
>>> Andrew (or anyone else) do you have any objection to this patch? I
>>> assume Seth is on an extended vacation; maybe you could add this to
>>> your mmotm? If Seth prefers changes to it he still has a couple
>>> months-ish until the next merge window. I could then send the
>>> follow-on patches, that allow zswap params to be set at runtime. I
>>> can resend them all as a series, if you prefer that.
>>
>> I'll take a look once the merge window mayhem settles down. But it
>> never hurts to do a refresh/retest/resend.
>
> Sure, let me rebase the whole thing onto the latest upstream, and I'll
> resend the series.
Seth,
I don't know what happened, but I never got any of your replies (in my
gmail account), although I see them in the list archives :(
Just to reset everything, I'll rebase the patches and resend them, and
we can continue the discussion. Sorry for the confusion!
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^ permalink raw reply [flat|nested] 22+ messages in thread
end of thread, other threads:[~2015-07-15 22:18 UTC | newest]
Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-06-04 12:02 [PATCH] zswap: dynamic pool creation Dan Streetman
2015-06-04 12:02 ` Dan Streetman
2015-06-04 12:13 ` Dan Streetman
2015-06-04 12:13 ` Dan Streetman
2015-06-10 20:54 ` Dan Streetman
2015-06-10 20:54 ` Dan Streetman
2015-06-11 18:51 ` Seth Jennings
2015-06-11 18:51 ` Seth Jennings
2015-06-18 15:57 ` Seth Jennings
2015-06-18 15:57 ` Seth Jennings
2015-06-17 23:13 ` Dan Streetman
2015-06-17 23:13 ` Dan Streetman
2015-06-18 15:21 ` Seth Jennings
2015-06-18 15:21 ` Seth Jennings
2015-06-25 20:22 ` Dan Streetman
2015-06-25 20:22 ` Dan Streetman
2015-06-25 20:35 ` Andrew Morton
2015-06-25 20:35 ` Andrew Morton
2015-06-25 20:37 ` Dan Streetman
2015-06-25 20:37 ` Dan Streetman
2015-07-15 22:18 ` Dan Streetman
2015-07-15 22:18 ` Dan Streetman
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