Re: [PATCH] mm/oom_kill.c: don't kill TASK_UNINTERRUPTIBLE tasks

From: Oleg Nesterov
Date: Fri Sep 18 2015 - 12:57:44 EST


On 09/19, Tetsuo Handa wrote:
>
> Oleg Nesterov wrote:
> > To simplify the discussion lets ignore PF_FROZEN, this is another issue.
> >
> > I am not sure this change is enough, we need to ensure that
> > select_bad_process() won't pick the same task (or its sub-thread) again.
>
> SysRq-f is sometimes unusable because it continues choosing the same thread.
> oom_kill_process() should not choose a thread which already has TIF_MEMDIE.

So I was right, this is really not enough...

> I think we need to rewrite oom_kill_process().

Heh. I can only ack the intent and wish you good luck ;)

> > And perhaps something like
> >
> > wait_event_timeout(oom_victims_wait, !oom_victims,
> > configurable_timeout);
> >
> > before select_bad_process() makes sense?
>
> I think you should not sleep for long with oom_lock mutex held.
> http://marc.info/?l=linux-mm&m=143031212312459

Yes, yes, sure, I didn't mean we should wait under oom_lock.

Oleg.

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