From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yafang Shao <laoar.shao@gmail.com>,
David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>
Subject: Re: [PATCH] mm, oom: show process exiting information in __oom_kill_process()
Date: Mon, 20 Jul 2020 16:23:56 +0200 [thread overview]
Message-ID: <20200720142356.GI4074@dhcp22.suse.cz> (raw)
In-Reply-To: <a4df8ecc-7764-e0fd-8778-3a2cdcd526c0@i-love.sakura.ne.jp>
On Mon 20-07-20 23:03:46, Tetsuo Handa wrote:
> On 2020/07/20 22:41, Michal Hocko wrote:
> >> Since we don't wake up the OOM reaper when hitting this path, unless __mmput()
> >> for this task itself immediately reclaims memory and updates the statistics
> >> counter, we just get two chunks of dump_header() messages and one OOM victim.
> >>
> >> Current synchronous printk() gives __mmput() some time for reclaiming memory
> >> and updating the statistics counter. But when printk() becomes asynchronous,
> >> there might be quite small time. People might wonder "why killed message
> >> follows immediately after skipped killing message"... Wouldn't the skip
> >> message confuse people?
> >
> > I would ask other way around. Wouldn't that give us a better clue that
> > the first oom invocation and the back off was a suboptimal decision? If
> > we learn about more of those, maybe we want to reconsider this heuristic
> > and rather retry the victim selection instead.
>
> I've just suggested
>
> Maybe the better behavior is to restart out_of_memory() without dump_header()
> (we can remember whether we already called dump_header() into "struct oom_control"),
> with last second watermark check before select_bad_process() and after dump_header().
>
> at https://lkml.kernel.org/r/7f58363a-db1a-5502-e2b4-ee4b9fa31824@i-love.sakura.ne.jp .
As soon as we learn about more of those as mentioned above.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-07-20 14:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-19 13:53 [PATCH] mm, oom: show process exiting information in __oom_kill_process() Yafang Shao
2020-07-19 23:20 ` Tetsuo Handa
2020-07-20 1:43 ` Yafang Shao
2020-07-20 7:16 ` Michal Hocko
2020-07-20 10:36 ` Yafang Shao
2020-07-20 11:06 ` Tetsuo Handa
2020-07-20 12:19 ` Yafang Shao
2020-07-20 13:11 ` Tetsuo Handa
2020-07-20 13:59 ` Yafang Shao
2020-07-20 13:41 ` Michal Hocko
2020-07-20 14:03 ` Tetsuo Handa
2020-07-20 14:23 ` Michal Hocko [this message]
2020-07-20 13:35 ` Michal Hocko
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