From: Shakeel Butt <shakeelb@google.com>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Ivan Babrou <ivan@cloudflare.com>,
Cgroups <cgroups@vger.kernel.org>, Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Daniel Dao <dqminh@cloudflare.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] memcg: async flush memcg stats from perf sensitive codepaths
Date: Mon, 28 Feb 2022 14:46:44 -0800 [thread overview]
Message-ID: <CALvZod61XyMJzrvU0Wvp8iWV878rZQYsa407RhoZYeiJV5j5SQ@mail.gmail.com> (raw)
In-Reply-To: <20220228184653.GA1812@blackbody.suse.cz>
On Mon, Feb 28, 2022 at 10:46 AM Michal Koutný <mkoutny@suse.com> wrote:
>
> On Fri, Feb 25, 2022 at 05:42:57PM -0800, Shakeel Butt <shakeelb@google.com> wrote:
> > Yes, the right fix would be to optimize the flushing code (but that
> > would require more work/time). However I still think letting
> > performance critical code paths to skip the sync flush would be good
> > in general. So, if the current patch is not to your liking we can
> > remove mem_cgroup_flush_stats() from workingset_refault().
>
> What about flushing just the subtree of the memcg where the refault
> happens?
> It doesn't reduce the overall work and there's still full-tree
> cgroup_rstat_lock but it should make the chunks of work smaller
> durations more regular.
>
We can try that and I will send a patch to Ivan and Daniel to try on
their workload to see the real impact of targeted memcg flushing.
However I am not very optimistic about it.
next prev parent reply other threads:[~2022-02-28 22:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-26 0:24 Shakeel Butt
2022-02-26 0:58 ` Andrew Morton
2022-02-26 1:20 ` Andrew Morton
2022-02-26 1:42 ` Shakeel Butt
2022-02-28 18:46 ` Michal Koutný
2022-02-28 22:46 ` Shakeel Butt [this message]
2022-02-26 2:32 ` kernel test robot
2022-02-26 12:43 ` kernel test robot
2022-03-01 9:05 ` Michal Hocko
2022-03-01 17:21 ` Shakeel Butt
2022-03-01 17:57 ` Michal Koutný
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