From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: Yang Shi <shy828301@gmail.com>,
guro@fb.com, shakeelb@google.com, david@fromorbit.com,
hannes@cmpxchg.org, mhocko@suse.com, akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [v3 PATCH 04/11] mm: vmscan: remove memcg_shrinker_map_size
Date: Wed, 6 Jan 2021 13:15:13 +0300 [thread overview]
Message-ID: <955422c5-0703-e9fb-f309-6ed6b5fc0e0a@virtuozzo.com> (raw)
In-Reply-To: <20210105225817.1036378-5-shy828301@gmail.com>
On 06.01.2021 01:58, Yang Shi wrote:
> Both memcg_shrinker_map_size and shrinker_nr_max is maintained, but actually the
> map size can be calculated via shrinker_nr_max, so it seems unnecessary to keep both.
> Remove memcg_shrinker_map_size since shrinker_nr_max is also used by iterating the
> bit map.
>
> Signed-off-by: Yang Shi <shy828301@gmail.com>
> ---
> mm/vmscan.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index ddb9f972f856..8da765a85569 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -185,8 +185,7 @@ static LIST_HEAD(shrinker_list);
> static DECLARE_RWSEM(shrinker_rwsem);
>
> #ifdef CONFIG_MEMCG
> -
> -static int memcg_shrinker_map_size;
> +static int shrinker_nr_max;
>
> static void memcg_free_shrinker_map_rcu(struct rcu_head *head)
> {
> @@ -248,7 +247,7 @@ int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
> return 0;
>
> down_read(&shrinker_rwsem);
> - size = memcg_shrinker_map_size;
> + size = DIV_ROUND_UP(shrinker_nr_max, BITS_PER_LONG) * sizeof(unsigned long);
> for_each_node(nid) {
> map = kvzalloc(sizeof(*map) + size, GFP_KERNEL);
> if (!map) {
> @@ -269,7 +268,7 @@ static int memcg_expand_shrinker_maps(int new_id)
> struct mem_cgroup *memcg;
>
> size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
> - old_size = memcg_shrinker_map_size;
> + old_size = DIV_ROUND_UP(shrinker_nr_max, BITS_PER_LONG) * sizeof(unsigned long);
> if (size <= old_size)
> return 0;
These bunch of DIV_ROUND_UP() looks too complex. Since now all the shrinker maps allocation
logic in the only file, can't we simplify this to look better? I mean something like below
to merge in your patch:
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b951c289ef3a..27b6371a1656 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -247,7 +247,7 @@ int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
return 0;
down_read(&shrinker_rwsem);
- size = DIV_ROUND_UP(shrinker_nr_max, BITS_PER_LONG) * sizeof(unsigned long);
+ size = shrinker_nr_max / BITS_PER_BYTE;
for_each_node(nid) {
map = kvzalloc(sizeof(*map) + size, GFP_KERNEL);
if (!map) {
@@ -264,13 +264,11 @@ int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
static int memcg_expand_shrinker_maps(int new_id)
{
- int size, old_size, ret = 0;
+ int size, old_size, new_nr_max, ret = 0;
struct mem_cgroup *memcg;
size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
- old_size = DIV_ROUND_UP(shrinker_nr_max, BITS_PER_LONG) * sizeof(unsigned long);
- if (size <= old_size)
- return 0;
+ new_nr_max = size * BITS_PER_BYTE;
if (!root_mem_cgroup)
goto out;
@@ -287,6 +285,9 @@ static int memcg_expand_shrinker_maps(int new_id)
} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
out:
+ if (ret == 0)
+ shrinker_nr_max = new_nr_max;
+
return ret;
}
@@ -334,8 +335,6 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
idr_remove(&shrinker_idr, id);
goto unlock;
}
-
- shrinker_nr_max = id + 1;
}
shrinker->id = id;
ret = 0;
next prev parent reply other threads:[~2021-01-06 10:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-05 22:58 [RFC v3 PATCH 0/11] Make shrinker's nr_deferred memcg aware Yang Shi
2021-01-05 22:58 ` [v3 PATCH 01/11] mm: vmscan: use nid from shrink_control for tracepoint Yang Shi
2021-01-05 22:58 ` [v3 PATCH 02/11] mm: vmscan: consolidate shrinker_maps handling code Yang Shi
2021-01-07 0:13 ` Roman Gushchin
2021-01-07 17:29 ` Yang Shi
2021-01-11 19:00 ` Yang Shi
2021-01-11 19:37 ` Roman Gushchin
2021-01-11 19:43 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 03/11] mm: vmscan: use shrinker_rwsem to protect shrinker_maps allocation Yang Shi
2021-01-06 9:54 ` Kirill Tkhai
2021-01-11 17:08 ` Yang Shi
2021-01-11 17:33 ` Kirill Tkhai
2021-01-11 18:57 ` Yang Shi
2021-01-11 21:33 ` Kirill Tkhai
2021-01-12 21:23 ` Yang Shi
2021-01-13 18:16 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 04/11] mm: vmscan: remove memcg_shrinker_map_size Yang Shi
2021-01-06 10:15 ` Kirill Tkhai [this message]
2021-01-11 17:44 ` Yang Shi
2021-01-13 23:48 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 05/11] mm: vmscan: use a new flag to indicate shrinker is registered Yang Shi
2021-01-06 10:21 ` Kirill Tkhai
2021-01-11 18:17 ` Yang Shi
2021-01-11 21:37 ` Kirill Tkhai
2021-01-12 20:58 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 06/11] mm: memcontrol: rename shrinker_map to shrinker_info Yang Shi
2021-01-06 11:38 ` Kirill Tkhai
2021-01-11 18:19 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 07/11] mm: vmscan: add per memcg shrinker nr_deferred Yang Shi
2021-01-06 11:06 ` Kirill Tkhai
2021-01-11 18:24 ` Yang Shi
2021-01-13 23:30 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 08/11] mm: vmscan: use per memcg nr_deferred of shrinker Yang Shi
2021-01-07 0:17 ` Roman Gushchin
2021-01-07 17:34 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 09/11] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers Yang Shi
2021-01-06 11:15 ` Kirill Tkhai
2021-01-11 18:40 ` Yang Shi
2021-01-11 21:57 ` Kirill Tkhai
2021-01-05 22:58 ` [v3 PATCH 10/11] mm: memcontrol: reparent nr_deferred when memcg offline Yang Shi
2021-01-06 11:34 ` Kirill Tkhai
2021-01-11 18:43 ` Yang Shi
2021-01-05 22:58 ` [v3 PATCH 11/11] mm: vmscan: shrink deferred objects proportional to priority Yang Shi
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