From: Michal Hocko <mhocko@suse.com>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
rientjes@google.com, mjaggi@caviumnetworks.com, oleg@redhat.com,
vdavydov.dev@gmail.com, torvalds@linux-foundation.org
Subject: Re: [PATCH] mm,oom: Warn on racing with MMF_OOM_SKIP at task_will_free_mem(current).
Date: Tue, 26 Sep 2017 13:39:51 +0200 [thread overview]
Message-ID: <20170926113951.g5dr4rplcbjjugno@dhcp22.suse.cz> (raw)
In-Reply-To: <201709262027.IJC34322.tMFOJFSOFVLHQO@I-love.SAKURA.ne.jp>
On Tue 26-09-17 20:27:40, Tetsuo Handa wrote:
[...]
> @@ -794,8 +794,10 @@ static bool task_will_free_mem(struct task_struct *task)
> * This task has already been drained by the oom reaper so there are
> * only small chances it will free some more
> */
> - if (test_bit(MMF_OOM_SKIP, &mm->flags))
> + if (test_bit(MMF_OOM_SKIP, &mm->flags)) {
> + WARN(1, "Racing OOM victim selection. Please report to linux-mm@kvack.org if you saw this warning from non-artificial workloads.\n");
> return false;
> + }
This can easily happen even without a race. Just consider that OOM
memory reserves got depleted. I think that the existing oom report will
tell us that the race happened by checking the mm counters.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-09-26 11:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1506070646-4549-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>
2017-09-25 14:30 ` [PATCH] [PATCH v3] mm, oom: task_will_free_mem(current) should ignore MMF_OOM_SKIP for once Michal Hocko
2017-09-25 15:09 ` Tetsuo Handa
2017-09-26 11:27 ` [PATCH] mm,oom: Warn on racing with MMF_OOM_SKIP at task_will_free_mem(current) Tetsuo Handa
2017-09-26 11:39 ` Michal Hocko [this message]
2017-09-27 5:00 ` Tetsuo Handa
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