From: Michal Hocko <mhocko@kernel.org>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: rientjes@google.com, akpm@linux-foundation.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm, oom: don't invoke oom killer if current has been reapered
Date: Mon, 13 Jul 2020 08:21:32 +0200 [thread overview]
Message-ID: <20200713062132.GB16783@dhcp22.suse.cz> (raw)
In-Reply-To: <20200713060154.GA16783@dhcp22.suse.cz>
On Mon 13-07-20 08:01:57, Michal Hocko wrote:
> On Fri 10-07-20 23:18:01, Yafang Shao wrote:
[...]
> > There're many threads of a multi-threaded task parallel running in a
> > container on many cpus. Then many threads triggered OOM at the same time,
> >
> > CPU-1 CPU-2 ... CPU-n
> > thread-1 thread-2 ... thread-n
> >
> > wait oom_lock wait oom_lock ... hold oom_lock
> >
> > (sigkill received)
> >
> > select current as victim
> > and wakeup oom reaper
> >
> > release oom_lock
> >
> > (MMF_OOM_SKIP set by oom reaper)
> >
> > (lots of pages are freed)
> > hold oom_lock
>
> Could you be more specific please? The page allocator never waits for
> the oom_lock and keeps retrying instead. Also __alloc_pages_may_oom
> tries to allocate with the lock held.
I suspect that you are looking at memcg oom killer. Because we do not do
trylock there for some reason I do not immediatelly remember from top of
my head. If this is really the case then I would recommend looking into
how the page allocator implements this and follow the same pattern for
memcg as well.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-07-13 6:21 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-11 3:18 [PATCH] mm, oom: don't invoke oom killer if current has been reapered Yafang Shao
2020-07-11 5:37 ` Yafang Shao
2020-07-13 6:01 ` Michal Hocko
2020-07-13 6:21 ` Michal Hocko [this message]
2020-07-13 12:24 ` Yafang Shao
2020-07-13 12:45 ` Michal Hocko
2020-07-13 13:11 ` Yafang Shao
2020-07-13 19:05 ` Michal Hocko
2020-07-14 0:15 ` Tetsuo Handa
2020-07-14 0:18 ` Tetsuo Handa
2020-07-14 2:09 ` Yafang Shao
2020-07-13 23:50 ` Tetsuo Handa
2020-07-14 2:13 ` Yafang Shao
2020-07-14 2:42 ` Tetsuo Handa
2020-07-14 2:58 ` Yafang Shao
2020-07-14 4:06 ` Tetsuo Handa
2020-07-14 5:03 ` Yafang Shao
2020-07-14 6:51 ` Michal Hocko
2020-07-14 6:43 ` Michal Hocko
2020-07-14 9:30 ` Yafang Shao
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