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From: "T.J. Mercier" <tjmercier@google.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	 Shakeel Butt <shakeelb@google.com>,
	Muchun Song <muchun.song@linux.dev>,
	 Andrew Morton <akpm@linux-foundation.org>,
	android-mm@google.com,  Minchan Kim <minchan@google.com>,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	 linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: memcg: Don't periodically flush stats when memcg is disabled
Date: Fri, 26 Jan 2024 13:20:48 -0800	[thread overview]
Message-ID: <CABdmKX2mZwVHSvJekT8UNt2a0WiiNnTTW-ZV=ZHvx0D1PoJuhQ@mail.gmail.com> (raw)
In-Reply-To: <20240126210642.GK1567330@cmpxchg.org>

On Fri, Jan 26, 2024 at 1:06 PM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Fri, Jan 26, 2024 at 08:33:52PM +0000, T.J. Mercier wrote:
> > The root memcg is onlined even when memcg is disabled. When it's onlined
> > a 2 second periodic stat flush is started, but no stat flushing is
> > required when memcg is disabled because there can be no child memcgs.
> > Most calls to flush memcg stats are avoided when memcg is disabled as a
> > result of the mem_cgroup_disabled check [1] added in [2], but the
> > periodic flushing started in mem_cgroup_css_online is not. Skip it.
> >
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/memcontrol.c?h=v6.8-rc1#n753
> > [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7d7ef0a4686abe43cd76a141b340a348f45ecdf2
> >
> > Fixes: aa48e47e3906 ("memcg: infrastructure to flush memcg stats")
> > Reported-by: Minchan Kim <minchan@google.com>
> > Signed-off-by: T.J. Mercier <tjmercier@google.com>
>
> With what Shakeel pointed out resolved:
>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Thanks Shakeel and Johannes. v2 is here, hopefully fixed up correctly:
https://lore.kernel.org/all/20240126211927.1171338-1-tjmercier@google.com/

      reply	other threads:[~2024-01-26 21:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-26 20:33 [PATCH] mm: memcg: Don't periodically flush stats when memcg is disabled T.J. Mercier
2024-01-26 21:02 ` Shakeel Butt
2024-01-26 21:06 ` Johannes Weiner
2024-01-26 21:20   ` T.J. Mercier [this message]

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