Re: [PATCH 1/2] mm: add sysctl to control global OOM logging behaviour

[Dmitry Monakhov <dmonakhov-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>]

Tetsuo Handa <penguin-kernel-JPay3/Yim36HaxMnTkn67Xf5DAMn2ifp@public.gmane.org> writes:

> On 2017/11/08 18:18, Dmitry Monakhov wrote:
>> Our systems becomes bigger and bigger, but OOM still happens.
>> This becomes serious problem for systems where OOM happens
>> frequently(containers, VM) because each OOM generate pressure
>> on dmesg log infrastructure. Let's allow system administrator
>> ability to tune OOM dump behaviour
>
> Majority of OOM killer related messages are from dump_header().
> Thus, allow tuning __ratelimit(&oom_rs) might make sense.
>
> But other lines
>
>   "%s: Kill process %d (%s) score %u or sacrifice child\n"
>   "Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n"
>   "oom_reaper: reaped process %d (%s), now anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n"
This still may result in hundreds of messages per second.
So it would be nice to have option to disable OOM logging.
> should not cause problems, for it is easy to exclude such lines from
> your dmesg log infrastructure using fgrep match.
In fact I've considered an abbility to use even more
fine grained log level control:
0: no oom log at all
1: dump only single line logs ( from oom_kill_process and reaper_task)
2: 1+ dump headers
3: 2+ task_stack (which previously controlled by sysctl_oom_dump_task)
What do you think?
>
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