Re: [PATCH] mm: memcontrol: update state_local when flushing NMI stats

[Tao Cui]

在 2026/7/13 16:50, Guopeng Zhang 写道:
> From: Guopeng Zhang <zhangguopeng@xxxxxxxxxx>
> 
> 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@xxxxxxxxxx>
> ---
>  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@xxxxxxxxxx>