* [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void
@ 2026-07-13 9:37 Guopeng Zhang
2026-07-13 10:11 ` Michal Hocko
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Guopeng Zhang @ 2026-07-13 9:37 UTC (permalink / raw)
To: Andrew Morton, Johannes Weiner
Cc: Michal Hocko, Roman Gushchin, Shakeel Butt, Muchun Song, cgroups,
linux-mm, linux-kernel, Guopeng Zhang
From: Guopeng Zhang <zhangguopeng@kylinos.cn>
Commit 7d74b06f240f ("memcg: use for_each_mem_cgroup") replaced the
mem_cgroup_walk_tree() call in mem_cgroup_oom_notify() with
for_each_mem_cgroup_tree(), but left mem_cgroup_oom_notify_cb() with the
int return type required by the old callback interface.
The function now has a single direct caller and no failure path. Make it
return void.
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
---
mm/memcontrol-v1.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index e8b6e1560278..73bea1b5c8dd 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -752,7 +752,7 @@ static int compare_thresholds(const void *a, const void *b)
return 0;
}
-static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
+static void mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
{
struct mem_cgroup_eventfd_list *ev;
@@ -762,7 +762,6 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
eventfd_signal(ev->eventfd);
spin_unlock(&memcg_oom_lock);
- return 0;
}
static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void
2026-07-13 9:37 [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void Guopeng Zhang
@ 2026-07-13 10:11 ` Michal Hocko
2026-07-13 11:43 ` Johannes Weiner
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Michal Hocko @ 2026-07-13 10:11 UTC (permalink / raw)
To: Guopeng Zhang
Cc: Andrew Morton, Johannes Weiner, Roman Gushchin, Shakeel Butt,
Muchun Song, cgroups, linux-mm, linux-kernel, Guopeng Zhang
On Mon 13-07-26 17:37:37, Guopeng Zhang wrote:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> Commit 7d74b06f240f ("memcg: use for_each_mem_cgroup") replaced the
> mem_cgroup_walk_tree() call in mem_cgroup_oom_notify() with
> for_each_mem_cgroup_tree(), but left mem_cgroup_oom_notify_cb() with the
> int return type required by the old callback interface.
>
> The function now has a single direct caller and no failure path. Make it
> return void.
>
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Acked-by: Michal Hocko <mhocko@suse.com>
Thanks!
> ---
> mm/memcontrol-v1.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
> index e8b6e1560278..73bea1b5c8dd 100644
> --- a/mm/memcontrol-v1.c
> +++ b/mm/memcontrol-v1.c
> @@ -752,7 +752,7 @@ static int compare_thresholds(const void *a, const void *b)
> return 0;
> }
>
> -static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
> +static void mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
> {
> struct mem_cgroup_eventfd_list *ev;
>
> @@ -762,7 +762,6 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
> eventfd_signal(ev->eventfd);
>
> spin_unlock(&memcg_oom_lock);
> - return 0;
> }
>
> static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
> --
> 2.43.0
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void
2026-07-13 9:37 [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void Guopeng Zhang
2026-07-13 10:11 ` Michal Hocko
@ 2026-07-13 11:43 ` Johannes Weiner
2026-07-13 12:34 ` Muchun Song
2026-07-14 0:27 ` SJ Park
3 siblings, 0 replies; 5+ messages in thread
From: Johannes Weiner @ 2026-07-13 11:43 UTC (permalink / raw)
To: Guopeng Zhang
Cc: Andrew Morton, Michal Hocko, Roman Gushchin, Shakeel Butt,
Muchun Song, cgroups, linux-mm, linux-kernel, Guopeng Zhang
On Mon, Jul 13, 2026 at 05:37:37PM +0800, Guopeng Zhang wrote:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> Commit 7d74b06f240f ("memcg: use for_each_mem_cgroup") replaced the
> mem_cgroup_walk_tree() call in mem_cgroup_oom_notify() with
> for_each_mem_cgroup_tree(), but left mem_cgroup_oom_notify_cb() with the
> int return type required by the old callback interface.
>
> The function now has a single direct caller and no failure path. Make it
> return void.
>
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void
2026-07-13 9:37 [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void Guopeng Zhang
2026-07-13 10:11 ` Michal Hocko
2026-07-13 11:43 ` Johannes Weiner
@ 2026-07-13 12:34 ` Muchun Song
2026-07-14 0:27 ` SJ Park
3 siblings, 0 replies; 5+ messages in thread
From: Muchun Song @ 2026-07-13 12:34 UTC (permalink / raw)
To: Guopeng Zhang
Cc: Andrew Morton, Johannes Weiner, Michal Hocko, Roman Gushchin,
Shakeel Butt, cgroups, linux-mm, linux-kernel, Guopeng Zhang
> On Jul 13, 2026, at 17:37, Guopeng Zhang <guopeng.zhang@linux.dev> wrote:
>
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> Commit 7d74b06f240f ("memcg: use for_each_mem_cgroup") replaced the
> mem_cgroup_walk_tree() call in mem_cgroup_oom_notify() with
> for_each_mem_cgroup_tree(), but left mem_cgroup_oom_notify_cb() with the
> int return type required by the old callback interface.
>
> The function now has a single direct caller and no failure path. Make it
> return void.
>
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void
2026-07-13 9:37 [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void Guopeng Zhang
` (2 preceding siblings ...)
2026-07-13 12:34 ` Muchun Song
@ 2026-07-14 0:27 ` SJ Park
3 siblings, 0 replies; 5+ messages in thread
From: SJ Park @ 2026-07-14 0:27 UTC (permalink / raw)
To: Guopeng Zhang
Cc: SJ Park, Andrew Morton, Johannes Weiner, Michal Hocko,
Roman Gushchin, Shakeel Butt, Muchun Song, cgroups, linux-mm,
linux-kernel, Guopeng Zhang
On Mon, 13 Jul 2026 17:37:37 +0800 Guopeng Zhang <guopeng.zhang@linux.dev> wrote:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> Commit 7d74b06f240f ("memcg: use for_each_mem_cgroup") replaced the
> mem_cgroup_walk_tree() call in mem_cgroup_oom_notify() with
> for_each_mem_cgroup_tree(), but left mem_cgroup_oom_notify_cb() with the
> int return type required by the old callback interface.
>
> The function now has a single direct caller and no failure path. Make it
> return void.
Makes sense to me.
>
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Reviewed-by: SJ Park <sj@kernel.org>
Thanks,
SJ
[...]
^ permalink raw reply [flat|nested] 5+ messages in thread
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2026-07-13 9:37 [PATCH] mm: memcg-v1: make mem_cgroup_oom_notify_cb() return void Guopeng Zhang
2026-07-13 10:11 ` Michal Hocko
2026-07-13 11:43 ` Johannes Weiner
2026-07-13 12:34 ` Muchun Song
2026-07-14 0:27 ` SJ Park
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