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From: "Michal Koutný" <mkoutny@suse.com>
To: Cai Xinchen <caixinchen1@huawei.com>
Cc: songmuchun@bytedance.com, akpm@linux-foundation.org,
	hannes@cmpxchg.org, longman@redhat.com, mhocko@kernel.org,
	roman.gushchin@linux.dev, shakeelb@google.com,
	cgroups@vger.kernel.org, duanxiongchun@bytedance.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	yosryahmed@google.com, mpenttil@redhat.com
Subject: Re: [PATCH 1/1] mm: memcontrol: fix vmstats_percpu state incorrect subtraction after reparent
Date: Fri, 24 Mar 2023 18:11:14 +0100	[thread overview]
Message-ID: <20230324171114.32oru5sdubfsfvgi@blackpad> (raw)
In-Reply-To: <20230320030648.50663-2-caixinchen1@huawei.com>

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Hello.

On Mon, Mar 20, 2023 at 03:06:48AM +0000, Cai Xinchen <caixinchen1@huawei.com> wrote:
> When memcg C is offllined, its pages are reparented to memcg P,
> so far P->vmstats (hierarchical) have those pages, and
> P->vmstats_percpu (non-hierarchical) don't. When those pages get
> uncharged, P->vmstats (hierachical) decreases, which is correct,
> but P->vmstats_percpu (non-hierarchical) also decreases, which
> is wrong, as those stats were never added to P->vmstats_percpu to
> begin with.

I was wondering why ->vmstats_percpu matters (in the end all is summed
in ->vmstats) -- do you mean this is a cgroup v1 only issue? As only
that exposes the non-hieararchical stats.

Thanks,
Michal

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WARNING: multiple messages have this Message-ID (diff)
From: "Michal Koutný" <mkoutny-IBi9RG/b67k@public.gmane.org>
To: Cai Xinchen <caixinchen1-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: songmuchun-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org,
	akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
	hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org,
	longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	roman.gushchin-fxUVXftIFDnyG1zEObXtfA@public.gmane.org,
	shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	duanxiongchun-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	yosryahmed-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
	mpenttil-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
Subject: Re: [PATCH 1/1] mm: memcontrol: fix vmstats_percpu state incorrect subtraction after reparent
Date: Fri, 24 Mar 2023 18:11:14 +0100	[thread overview]
Message-ID: <20230324171114.32oru5sdubfsfvgi@blackpad> (raw)
In-Reply-To: <20230320030648.50663-2-caixinchen1-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

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Hello.

On Mon, Mar 20, 2023 at 03:06:48AM +0000, Cai Xinchen <caixinchen1-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> wrote:
> When memcg C is offllined, its pages are reparented to memcg P,
> so far P->vmstats (hierarchical) have those pages, and
> P->vmstats_percpu (non-hierarchical) don't. When those pages get
> uncharged, P->vmstats (hierachical) decreases, which is correct,
> but P->vmstats_percpu (non-hierarchical) also decreases, which
> is wrong, as those stats were never added to P->vmstats_percpu to
> begin with.

I was wondering why ->vmstats_percpu matters (in the end all is summed
in ->vmstats) -- do you mean this is a cgroup v1 only issue? As only
that exposes the non-hieararchical stats.

Thanks,
Michal

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  reply	other threads:[~2023-03-24 17:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-20  3:06 [PATCH 0/1] Fix vmstat_percpu incorrect subtraction after reparent Cai Xinchen
2023-03-20  3:06 ` Cai Xinchen
2023-03-20  3:06 ` [PATCH 1/1] mm: memcontrol: fix vmstats_percpu state " Cai Xinchen
2023-03-20  3:06   ` Cai Xinchen
2023-03-24 17:11   ` Michal Koutný [this message]
2023-03-24 17:11     ` Michal Koutný
2023-03-27  1:29     ` Cai Xinchen
2023-03-27  1:29       ` Cai Xinchen
2023-03-24 17:14 ` [PATCH 0/1] Fix vmstat_percpu " Michal Koutný
2023-03-24 17:14   ` Michal Koutný

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