From: Shakeel Butt <shakeelb@google.com>
To: Roman Gushchin <guro@fb.com>
Cc: Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
kernel-team@fb.com, Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
koct9i@gmail.com, Tejun Heo <tj@kernel.org>
Subject: Re: [RFC PATCH 2/2] mm: drain memcg stocks on css offlining
Date: Tue, 14 Aug 2018 17:54:13 -0700 [thread overview]
Message-ID: <CALvZod4qhJA3NHnV_cTO0XEH1d4u62vxwug707sti7cZL6bgPw@mail.gmail.com> (raw)
In-Reply-To: <20180815003620.15678-2-guro@fb.com>
On Tue, Aug 14, 2018 at 5:36 PM Roman Gushchin <guro@fb.com> wrote:
>
> Memcg charge is batched using per-cpu stocks, so an offline memcg
> can be pinned by a cached charge up to a moment, when a process
> belonging to some other cgroup will charge some memory on the same
> cpu. In other words, cached charges can prevent a memory cgroup
> from being reclaimed for some time, without any clear need.
>
> Let's optimize it by explicit draining of all stocks on css offlining.
> As draining is performed asynchronously, and is skipped if any
> parallel draining is happening, it's cheap.
>
> Signed-off-by: Roman Gushchin <guro@fb.com>
Seems reasonable.
Reviewed-by: Shakeel Butt <shakeelb@google.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Konstantin Khlebnikov <koct9i@gmail.com>
> Cc: Tejun Heo <tj@kernel.org>
> ---
> mm/memcontrol.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 4e3c1315b1de..cfb64b5b9957 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4575,6 +4575,8 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
> memcg_offline_kmem(memcg);
> wb_memcg_offline(memcg);
>
> + drain_all_stock(memcg);
> +
> mem_cgroup_id_put(memcg);
> }
>
> --
> 2.14.4
>
next prev parent reply other threads:[~2018-08-15 0:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-15 0:36 [RFC PATCH 1/2] mm: rework memcg kernel stack accounting Roman Gushchin
2018-08-15 0:36 ` [RFC PATCH 2/2] mm: drain memcg stocks on css offlining Roman Gushchin
2018-08-15 0:54 ` Shakeel Butt [this message]
2018-08-15 7:29 ` Michal Hocko
2018-08-15 1:18 ` [RFC PATCH 1/2] mm: rework memcg kernel stack accounting Shakeel Butt
2018-08-15 17:16 ` Roman Gushchin
2018-08-15 7:10 ` Michal Hocko
2018-08-15 16:39 ` Johannes Weiner
2018-08-15 16:55 ` Roman Gushchin
2018-08-15 17:12 ` Andy Lutomirski
2018-08-15 17:25 ` Roman Gushchin
2018-08-15 17:32 ` Shakeel Butt
2018-08-15 17:37 ` Andy Lutomirski
2018-08-21 17:22 ` Roman Gushchin
2018-08-15 17:20 ` Johannes Weiner
2018-08-16 6:35 ` Michal Hocko
2018-08-16 15:24 ` Roman Gushchin
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