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From: "Darrick J. Wong" <djwong@kernel.org>
To: djwong@kernel.org, ebiggers@kernel.org, aalbersh@redhat.com
Cc: linux-fsdevel@vger.kernel.org, fsverity@lists.linux.dev,
	linux-xfs@vger.kernel.org
Subject: [PATCH 29/40] xfs: shrink verity blob cache
Date: Sun, 17 Mar 2024 09:30:57 -0700	[thread overview]
Message-ID: <171069246376.2684506.9738125055810923344.stgit@frogsfrogsfrogs> (raw)
In-Reply-To: <171069245829.2684506.10682056181611490828.stgit@frogsfrogsfrogs>

From: Darrick J. Wong <djwong@kernel.org>

Add some shrinkers so that reclaim can free cached merkle tree blocks
when memory is tight.  We add a shrinkref variable to bias reclaim
against freeing the upper levels of the merkle tree in the hope of
maintaining read performance.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_trace.h  |    1 +
 fs/xfs/xfs_verity.c |   87 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)


diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 91a73399114e..37ea6822cca3 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4797,6 +4797,7 @@ DEFINE_EVENT(xfs_verity_cache_class, name, \
 DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_load);
 DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_store);
 DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_drop);
+DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_reclaim);
 
 TRACE_EVENT(xfs_verity_shrinker_count,
 	TP_PROTO(struct xfs_mount *mp, unsigned long long count,
diff --git a/fs/xfs/xfs_verity.c b/fs/xfs/xfs_verity.c
index 8d1888353515..c19fa47d1f76 100644
--- a/fs/xfs/xfs_verity.c
+++ b/fs/xfs/xfs_verity.c
@@ -42,6 +42,9 @@ struct xfs_merkle_blob {
 	/* refcount of this item; the cache holds its own ref */
 	refcount_t		refcount;
 
+	/* number of times the shrinker should ignore this item */
+	atomic_t		shrinkref;
+
 	unsigned long		flags;
 
 	/* Pointer to the merkle tree block, which is power-of-2 sized */
@@ -72,6 +75,7 @@ xfs_merkle_blob_alloc(
 
 	/* Caller owns this refcount. */
 	refcount_set(&mk->refcount, 1);
+	atomic_set(&mk->shrinkref, 0);
 	mk->flags = 0;
 	return mk;
 }
@@ -104,8 +108,10 @@ xfs_verity_cache_drop(
 	struct xfs_inode	*ip)
 {
 	XA_STATE(xas, &ip->i_merkle_blocks, 0);
+	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_merkle_blob	*mk;
 	unsigned long		flags;
+	s64			freed = 0;
 
 	xas_lock_irqsave(&xas, flags);
 	xas_for_each(&xas, mk, ULONG_MAX) {
@@ -113,10 +119,13 @@ xfs_verity_cache_drop(
 
 		trace_xfs_verity_cache_drop(ip, xas.xa_index, _RET_IP_);
 
+		freed++;
 		xas_store(&xas, NULL);
 		xfs_merkle_blob_rele(mk);
 	}
+	percpu_counter_sub(&mp->m_verity_blocks, freed);
 	xas_unlock_irqrestore(&xas, flags);
+	xfs_inode_clear_verity_tag(ip);
 }
 
 /* Destroy the merkle tree block cache */
@@ -175,6 +184,7 @@ xfs_verity_cache_store(
 	unsigned long		key,
 	struct xfs_merkle_blob	*mk)
 {
+	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_merkle_blob	*old;
 	unsigned long		flags;
 
@@ -189,6 +199,8 @@ xfs_verity_cache_store(
 		old = __xa_cmpxchg(&ip->i_merkle_blocks, key, NULL, mk,
 				GFP_KERNEL);
 	} while (old && !refcount_inc_not_zero(&old->refcount));
+	if (!old)
+		percpu_counter_add(&mp->m_verity_blocks, 1);
 	xa_unlock_irqrestore(&ip->i_merkle_blocks, flags);
 
 	if (old == NULL) {
@@ -234,12 +246,73 @@ struct xfs_verity_scan {
 	unsigned long		freed;
 };
 
+/* Reclaim inactive merkle tree blocks that have run out of second chances. */
+static void
+xfs_verity_cache_reclaim(
+	struct xfs_inode	*ip,
+	struct xfs_verity_scan	*vs)
+{
+	XA_STATE(xas, &ip->i_merkle_blocks, 0);
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_merkle_blob	*mk;
+	unsigned long		flags;
+	s64			freed = 0;
+
+	xas_lock_irqsave(&xas, flags);
+	xas_for_each(&xas, mk, ULONG_MAX) {
+		/*
+		 * Tell the shrinker that we scanned this merkle tree block,
+		 * even if we don't remove it.
+		 */
+		vs->scanned++;
+		if (vs->sc->nr_to_scan-- == 0)
+			break;
+
+		/* Retain if there are active references */
+		if (refcount_read(&mk->refcount) > 1)
+			continue;
+
+		/* Ignore if the item still has lru refcount */
+		if (atomic_add_unless(&mk->shrinkref, -1, 0))
+			continue;
+
+		trace_xfs_verity_cache_reclaim(ip, xas.xa_index, _RET_IP_);
+
+		freed++;
+		xas_store(&xas, NULL);
+		xfs_merkle_blob_rele(mk);
+	}
+	percpu_counter_sub(&mp->m_verity_blocks, freed);
+	xas_unlock_irqrestore(&xas, flags);
+
+	/*
+	 * Try to clear the verity tree tag if we reclaimed all the cached
+	 * blocks.  On the flag setting side, we should have IOLOCK_SHARED.
+	 */
+	xfs_ilock(ip, XFS_IOLOCK_EXCL);
+	if (xa_empty(&ip->i_merkle_blocks))
+		xfs_inode_clear_verity_tag(ip);
+	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+
+	vs->freed += freed;
+}
+
 /* Scan an inode as part of a verity scan. */
 int
 xfs_verity_scan_inode(
 	struct xfs_inode	*ip,
 	struct xfs_icwalk	*icw)
 {
+	struct xfs_verity_scan	*vs;
+
+	vs = container_of(icw, struct xfs_verity_scan, icw);
+
+	if (vs->sc->nr_to_scan > 0)
+		xfs_verity_cache_reclaim(ip, vs);
+
+	if (vs->sc->nr_to_scan == 0)
+		xfs_icwalk_verity_stop(icw);
+
 	xfs_irele(ip);
 	return 0;
 }
@@ -512,6 +585,13 @@ xfs_verity_read_merkle(
 		 * Free the new cache blob and continue with the existing one.
 		 */
 		xfs_merkle_blob_rele(new_mk);
+	} else {
+		/*
+		 * We added this merkle tree block to the cache; tag the inode
+		 * so that reclaim will scan this inode.  The caller holds
+		 * IOLOCK_SHARED this will not race with the shrinker.
+		 */
+		xfs_inode_set_verity_tag(ip);
 	}
 
 out_hit:
@@ -519,6 +599,13 @@ xfs_verity_read_merkle(
 	block->context = mk;
 	block->verified = test_bit(XFS_MERKLE_BLOB_VERIFIED_BIT, &mk->flags);
 
+	/*
+	 * Prioritize keeping the root-adjacent levels cached if this isn't a
+	 * streaming read.
+	 */
+	if (req->level >= 0)
+		atomic_set(&mk->shrinkref, req->level + 1);
+
 	return 0;
 
 out_new_mk:


  parent reply	other threads:[~2024-03-17 16:30 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-17 16:19 [PATCHBOMB v5.3] fs-verity support for XFS Darrick J. Wong
2024-03-17 16:22 ` [PATCHSET " Darrick J. Wong
2024-03-17 16:23   ` [PATCH 01/40] fsverity: remove hash page spin lock Darrick J. Wong
2024-03-17 16:23   ` [PATCH 02/40] xfs: add parent pointer support to attribute code Darrick J. Wong
2024-03-17 16:24   ` [PATCH 03/40] xfs: define parent pointer ondisk extended attribute format Darrick J. Wong
2024-03-17 16:24   ` [PATCH 04/40] xfs: add parent pointer validator functions Darrick J. Wong
2024-03-17 16:24   ` [PATCH 05/40] fs: add FS_XFLAG_VERITY for verity files Darrick J. Wong
2024-03-17 16:24   ` [PATCH 06/40] fsverity: pass tree_blocksize to end_enable_verity() Darrick J. Wong
2024-03-17 16:25   ` [PATCH 07/40] fsverity: support block-based Merkle tree caching Darrick J. Wong
2024-03-17 16:25   ` [PATCH 08/40] fsverity: add per-sb workqueue for post read processing Darrick J. Wong
2024-03-17 16:25   ` [PATCH 09/40] fsverity: add tracepoints Darrick J. Wong
2024-03-17 16:26   ` [PATCH 10/40] fsverity: fix "support block-based Merkle tree caching" Darrick J. Wong
2024-03-17 16:26   ` [PATCH 11/40] fsverity: send the level of the merkle tree block to ->read_merkle_tree_block Darrick J. Wong
2024-03-17 16:26   ` [PATCH 12/40] fsverity: pass the new tree size and block size to ->begin_enable_verity Darrick J. Wong
2024-03-17 16:26   ` [PATCH 13/40] fsverity: expose merkle tree geometry to callers Darrick J. Wong
2024-03-17 16:27   ` [PATCH 14/40] fsverity: rely on cached block callers to retain verified state Darrick J. Wong
2024-03-17 16:27   ` [PATCH 15/40] fsverity: box up the write_merkle_tree_block parameters too Darrick J. Wong
2024-03-17 16:27   ` [PATCH 16/40] fsverity: pass the zero-hash value to the implementation Darrick J. Wong
2024-03-18 16:38     ` Eric Biggers
2024-03-18 21:04       ` Darrick J. Wong
2024-03-17 16:27   ` [PATCH 17/40] fsverity: report validation errors back to the filesystem Darrick J. Wong
2024-03-17 16:28   ` [PATCH 18/40] iomap: integrate fs-verity verification into iomap's read path Darrick J. Wong
2024-03-17 16:28   ` [PATCH 19/40] xfs: add attribute type for fs-verity Darrick J. Wong
2024-03-17 16:28   ` [PATCH 20/40] xfs: add fs-verity ro-compat flag Darrick J. Wong
2024-03-17 16:28   ` [PATCH 21/40] xfs: add inode on-disk VERITY flag Darrick J. Wong
2024-03-17 16:29   ` [PATCH 22/40] xfs: initialize fs-verity on file open and cleanup on inode destruction Darrick J. Wong
2024-03-17 16:29   ` [PATCH 23/40] xfs: don't allow to enable DAX on fs-verity sealed inode Darrick J. Wong
2024-03-17 16:29   ` [PATCH 24/40] xfs: disable direct read path for fs-verity files Darrick J. Wong
2024-03-18 19:48     ` Andrey Albershteyn
2024-03-19 21:17       ` Darrick J. Wong
2024-03-17 16:29   ` [PATCH 25/40] xfs: widen flags argument to the xfs_iflags_* helpers Darrick J. Wong
2024-03-17 16:30   ` [PATCH 26/40] xfs: add fs-verity support Darrick J. Wong
2024-03-18  1:43     ` Christoph Hellwig
2024-03-18  4:34       ` Darrick J. Wong
2024-03-18  4:39         ` Christoph Hellwig
2024-03-18  4:56           ` Darrick J. Wong
2024-03-17 16:30   ` [PATCH 27/40] xfs: create a per-mount shrinker for verity inodes merkle tree blocks Darrick J. Wong
2024-03-17 16:30   ` [PATCH 28/40] xfs: create an icache tag for files with cached " Darrick J. Wong
2024-03-17 16:30   ` Darrick J. Wong [this message]
2024-03-17 16:31   ` [PATCH 30/40] xfs: clean up stale fsverity metadata before starting Darrick J. Wong
2024-03-18 17:50     ` Andrey Albershteyn
2024-03-17 16:31   ` [PATCH 31/40] xfs: better reporting and error handling in xfs_drop_merkle_tree Darrick J. Wong
2024-03-18 17:51     ` Andrey Albershteyn
2024-03-17 16:31   ` [PATCH 32/40] xfs: make scrub aware of verity dinode flag Darrick J. Wong
2024-03-17 16:32   ` [PATCH 33/40] xfs: add fs-verity ioctls Darrick J. Wong
2024-03-17 16:32   ` [PATCH 34/40] xfs: advertise fs-verity being available on filesystem Darrick J. Wong
2024-03-17 16:32   ` [PATCH 35/40] xfs: teach online repair to evaluate fsverity xattrs Darrick J. Wong
2024-03-18 17:34     ` Andrey Albershteyn
2024-03-19 21:27       ` Darrick J. Wong
2024-03-17 16:32   ` [PATCH 36/40] xfs: don't store trailing zeroes of merkle tree blocks Darrick J. Wong
2024-03-18 17:52     ` Andrey Albershteyn
2024-03-17 16:33   ` [PATCH 37/40] xfs: create separate name hash function for xattrs Darrick J. Wong
2024-03-18 17:53     ` Andrey Albershteyn
2024-03-17 16:33   ` [PATCH 38/40] xfs: use merkle tree offset as attr hash Darrick J. Wong
2024-03-18 17:55     ` Andrey Albershteyn
2024-03-17 16:33   ` [PATCH 39/40] xfs: don't bother storing merkle tree blocks for zeroed data blocks Darrick J. Wong
2024-03-18 17:56     ` Andrey Albershteyn
2024-03-17 16:33   ` [PATCH 40/40] xfs: enable ro-compat fs-verity flag Darrick J. Wong
2024-03-18 16:35   ` [PATCHSET v5.3] fs-verity support for XFS Eric Biggers
2024-03-19 22:07     ` Darrick J. Wong
2024-03-19 23:21       ` Darrick J. Wong
2024-03-20 10:16         ` Andrey Albershteyn
2024-03-20 15:11           ` Darrick J. Wong
2024-03-17 16:23 ` Darrick J. Wong
2024-03-17 16:34   ` [PATCH 01/20] xfsprogs: add parent pointer support to attribute code Darrick J. Wong
2024-03-17 16:34   ` [PATCH 02/20] xfsprogs: define parent pointer xattr format Darrick J. Wong
2024-03-17 16:34   ` [PATCH 03/20] xfsprogs: Add xfs_verify_pptr Darrick J. Wong
2024-03-17 16:34   ` [PATCH 04/20] fs: add FS_XFLAG_VERITY for verity files Darrick J. Wong
2024-03-17 16:35   ` [PATCH 05/20] xfs: add attribute type for fs-verity Darrick J. Wong
2024-03-17 16:35   ` [PATCH 06/20] xfs: add fs-verity ro-compat flag Darrick J. Wong
2024-03-17 16:35   ` [PATCH 07/20] xfs: add inode on-disk VERITY flag Darrick J. Wong
2024-03-17 16:35   ` [PATCH 08/20] xfs: add fs-verity support Darrick J. Wong
2024-03-17 16:36   ` [PATCH 09/20] xfs: advertise fs-verity being available on filesystem Darrick J. Wong
2024-03-17 16:36   ` [PATCH 10/20] xfs: create separate name hash function for xattrs Darrick J. Wong
2024-03-17 16:36   ` [PATCH 11/20] xfs: use merkle tree offset as attr hash Darrick J. Wong
2024-03-17 16:36   ` [PATCH 12/20] xfs: enable ro-compat fs-verity flag Darrick J. Wong
2024-03-17 16:37   ` [PATCH 13/20] libfrog: add fsverity to xfs_report_geom output Darrick J. Wong
2024-03-17 16:37   ` [PATCH 14/20] xfs_db: introduce attr_modify command Darrick J. Wong
2024-03-17 16:37   ` [PATCH 15/20] xfs_db: make attr_set/remove/modify be able to handle fs-verity attrs Darrick J. Wong
2024-03-17 16:37   ` [PATCH 16/20] man: document attr_modify command Darrick J. Wong
2024-03-17 16:38   ` [PATCH 17/20] xfs_db: dump verity features and metadata Darrick J. Wong
2024-03-17 16:38   ` [PATCH 18/20] xfs_db: dump merkle tree data Darrick J. Wong
2024-03-17 16:38   ` [PATCH 19/20] xfs_repair: junk fsverity xattrs when unnecessary Darrick J. Wong
2024-03-17 16:39   ` [PATCH 20/20] mkfs.xfs: add verity parameter Darrick J. Wong
2024-03-17 16:23 ` [PATCHSET v5.3] fstests: fs-verity support for XFS Darrick J. Wong
2024-03-17 16:39   ` [PATCH 1/3] common/verity: enable fsverity " Darrick J. Wong
2024-03-17 16:39   ` [PATCH 2/3] xfs/{021,122}: adapt to fsverity xattrs Darrick J. Wong
2024-03-19 14:59     ` Andrey Albershteyn
2024-03-19 19:25       ` Darrick J. Wong
2024-03-17 16:39   ` [PATCH 3/3] common/populate: add verity files to populate xfs images Darrick J. Wong
2024-03-18  1:39 ` [PATCHBOMB v5.3] fs-verity support for XFS Christoph Hellwig
2024-03-18  4:30   ` Darrick J. Wong

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