* [PATCH] mm: memcontrol: update state_local when flushing NMI stats
@ 2026-07-13 8:50 Guopeng Zhang
2026-07-13 10:22 ` Tao Cui
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Guopeng Zhang @ 2026-07-13 8:50 UTC (permalink / raw)
To: Andrew Morton, Shakeel Butt, Johannes Weiner
Cc: Michal Hocko, Roman Gushchin, Muchun Song, Vlastimil Babka,
Alexandre Ghiti, cgroups, linux-mm, linux-kernel, stable,
Guopeng Zhang
From: Guopeng Zhang <zhangguopeng@kylinos.cn>
flush_nmi_stats() updates state[] for kmem and slab counters but leaves
the corresponding state_local[] counters unchanged. Local kmem and
slab statistics therefore miss updates collected through the NMI-safe
atomic path.
Update state_local[] together with state[].
Fixes: 940b01fc8dc1 ("memcg: nmi safe memcg stats for specific archs")
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
---
mm/memcontrol.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 22f55aeb94f3..02599b8b6bd5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4443,6 +4443,7 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
int index = memcg_stats_index(MEMCG_KMEM);
memcg->vmstats->state[index] += kmem;
+ memcg->vmstats->state_local[index] += kmem;
if (parent)
parent->vmstats->state_pending[index] += kmem;
}
@@ -4460,9 +4461,11 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
int index = memcg_stats_index(NR_SLAB_RECLAIMABLE_B);
lstats->state[index] += slab;
+ lstats->state_local[index] += slab;
if (plstats)
plstats->state_pending[index] += slab;
memcg->vmstats->state[index] += slab;
+ memcg->vmstats->state_local[index] += slab;
if (parent)
parent->vmstats->state_pending[index] += slab;
}
@@ -4471,9 +4474,11 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
int index = memcg_stats_index(NR_SLAB_UNRECLAIMABLE_B);
lstats->state[index] += slab;
+ lstats->state_local[index] += slab;
if (plstats)
plstats->state_pending[index] += slab;
memcg->vmstats->state[index] += slab;
+ memcg->vmstats->state_local[index] += slab;
if (parent)
parent->vmstats->state_pending[index] += slab;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcontrol: update state_local when flushing NMI stats
2026-07-13 8:50 [PATCH] mm: memcontrol: update state_local when flushing NMI stats Guopeng Zhang
@ 2026-07-13 10:22 ` Tao Cui
2026-07-13 11:39 ` Johannes Weiner
2026-07-14 19:52 ` Shakeel Butt
2 siblings, 0 replies; 5+ messages in thread
From: Tao Cui @ 2026-07-13 10:22 UTC (permalink / raw)
To: Guopeng Zhang, Andrew Morton, Shakeel Butt, Johannes Weiner
Cc: cui.tao, Michal Hocko, Roman Gushchin, Muchun Song,
Vlastimil Babka, Alexandre Ghiti, cgroups, linux-mm, linux-kernel,
stable, Guopeng Zhang
在 2026/7/13 16:50, Guopeng Zhang 写道:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> flush_nmi_stats() updates state[] for kmem and slab counters but leaves
> the corresponding state_local[] counters unchanged. Local kmem and
> slab statistics therefore miss updates collected through the NMI-safe
> atomic path.
>
> Update state_local[] together with state[].
>
> Fixes: 940b01fc8dc1 ("memcg: nmi safe memcg stats for specific archs")
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
> ---
> mm/memcontrol.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 22f55aeb94f3..02599b8b6bd5 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4443,6 +4443,7 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
> int index = memcg_stats_index(MEMCG_KMEM);
>
> memcg->vmstats->state[index] += kmem;
> + memcg->vmstats->state_local[index] += kmem;
> if (parent)
> parent->vmstats->state_pending[index] += kmem;
> }
> @@ -4460,9 +4461,11 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
> int index = memcg_stats_index(NR_SLAB_RECLAIMABLE_B);
>
> lstats->state[index] += slab;
> + lstats->state_local[index] += slab;
> if (plstats)
> plstats->state_pending[index] += slab;
> memcg->vmstats->state[index] += slab;
> + memcg->vmstats->state_local[index] += slab;
> if (parent)
> parent->vmstats->state_pending[index] += slab;
> }
> @@ -4471,9 +4474,11 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
> int index = memcg_stats_index(NR_SLAB_UNRECLAIMABLE_B);
>
> lstats->state[index] += slab;
> + lstats->state_local[index] += slab;
> if (plstats)
> plstats->state_pending[index] += slab;
> memcg->vmstats->state[index] += slab;
> + memcg->vmstats->state_local[index] += slab;
> if (parent)
> parent->vmstats->state_pending[index] += slab;
> }
Looks correct — state_local[] mirrors state[] for this cgroup's own NMI-accounted kmem/slab charges, and pending→local is properly left untouched.
Acked-by: Tao Cui <cuitao@kylinos.cn>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcontrol: update state_local when flushing NMI stats
2026-07-13 8:50 [PATCH] mm: memcontrol: update state_local when flushing NMI stats Guopeng Zhang
2026-07-13 10:22 ` Tao Cui
@ 2026-07-13 11:39 ` Johannes Weiner
2026-07-14 19:51 ` Shakeel Butt
2026-07-14 19:52 ` Shakeel Butt
2 siblings, 1 reply; 5+ messages in thread
From: Johannes Weiner @ 2026-07-13 11:39 UTC (permalink / raw)
To: Guopeng Zhang
Cc: Andrew Morton, Shakeel Butt, Michal Hocko, Roman Gushchin,
Muchun Song, Vlastimil Babka, Alexandre Ghiti, cgroups, linux-mm,
linux-kernel, stable, Guopeng Zhang
On Mon, Jul 13, 2026 at 04:50:53PM +0800, Guopeng Zhang wrote:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> flush_nmi_stats() updates state[] for kmem and slab counters but leaves
> the corresponding state_local[] counters unchanged. Local kmem and
> slab statistics therefore miss updates collected through the NMI-safe
> atomic path.
>
> Update state_local[] together with state[].
>
> Fixes: 940b01fc8dc1 ("memcg: nmi safe memcg stats for specific archs")
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
This issue affects memcg1 but also the workingset shrinker.
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
And we should probably CC: stable # 6.15. Shakeel?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcontrol: update state_local when flushing NMI stats
2026-07-13 11:39 ` Johannes Weiner
@ 2026-07-14 19:51 ` Shakeel Butt
0 siblings, 0 replies; 5+ messages in thread
From: Shakeel Butt @ 2026-07-14 19:51 UTC (permalink / raw)
To: Johannes Weiner
Cc: Guopeng Zhang, Andrew Morton, Michal Hocko, Roman Gushchin,
Muchun Song, Vlastimil Babka, Alexandre Ghiti, cgroups, linux-mm,
linux-kernel, stable, Guopeng Zhang
On Mon, Jul 13, 2026 at 07:39:01AM -0400, Johannes Weiner wrote:
> On Mon, Jul 13, 2026 at 04:50:53PM +0800, Guopeng Zhang wrote:
> > From: Guopeng Zhang <zhangguopeng@kylinos.cn>
> >
> > flush_nmi_stats() updates state[] for kmem and slab counters but leaves
> > the corresponding state_local[] counters unchanged. Local kmem and
> > slab statistics therefore miss updates collected through the NMI-safe
> > atomic path.
> >
> > Update state_local[] together with state[].
> >
> > Fixes: 940b01fc8dc1 ("memcg: nmi safe memcg stats for specific archs")
> > Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> This issue affects memcg1 but also the workingset shrinker.
>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
>
> And we should probably CC: stable # 6.15. Shakeel?
Yes it makes sense.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] mm: memcontrol: update state_local when flushing NMI stats
2026-07-13 8:50 [PATCH] mm: memcontrol: update state_local when flushing NMI stats Guopeng Zhang
2026-07-13 10:22 ` Tao Cui
2026-07-13 11:39 ` Johannes Weiner
@ 2026-07-14 19:52 ` Shakeel Butt
2 siblings, 0 replies; 5+ messages in thread
From: Shakeel Butt @ 2026-07-14 19:52 UTC (permalink / raw)
To: Guopeng Zhang
Cc: Andrew Morton, Johannes Weiner, Michal Hocko, Roman Gushchin,
Muchun Song, Vlastimil Babka, Alexandre Ghiti, cgroups, linux-mm,
linux-kernel, stable, Guopeng Zhang
On Mon, Jul 13, 2026 at 04:50:53PM +0800, Guopeng Zhang wrote:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> flush_nmi_stats() updates state[] for kmem and slab counters but leaves
> the corresponding state_local[] counters unchanged. Local kmem and
> slab statistics therefore miss updates collected through the NMI-safe
> atomic path.
>
> Update state_local[] together with state[].
>
> Fixes: 940b01fc8dc1 ("memcg: nmi safe memcg stats for specific archs")
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2026-07-13 8:50 [PATCH] mm: memcontrol: update state_local when flushing NMI stats Guopeng Zhang
2026-07-13 10:22 ` Tao Cui
2026-07-13 11:39 ` Johannes Weiner
2026-07-14 19:51 ` Shakeel Butt
2026-07-14 19:52 ` Shakeel Butt
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