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From: David Rientjes <rientjes@google.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Michal Hocko <mhocko@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch] mm, oom: prevent soft lockup on memcg oom for UP systems
Date: Wed, 11 Mar 2020 15:14:39 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.21.2003111513180.195367@chino.kir.corp.google.com> (raw)
In-Reply-To: <993e7783-60e9-ba03-b512-c829b9e833fd@i-love.sakura.ne.jp>
On Thu, 12 Mar 2020, Tetsuo Handa wrote:
> > The cond_resched() here is needed if the iteration is lengthy depending on
> > the number of descendant memcgs already.
>
> No. cond_resched() here will become no-op if CONFIG_PREEMPTION=y and current
> thread has realtime priority.
>
It's helpful without CONFIG_PREEMPTION for excessively long memcg
iterations to avoid starving need_resched.
> > schedule_timeout_killable(1) does not make any guarantees that current
> > will be scheduled after the victim or oom_reaper on UP systems.
>
> The point of schedule_timeout_*(1) is to guarantee that current thread
> will yield CPU to other threads even if CONFIG_PREEMPTION=y and current
> thread has realtime priority case. There is no guarantee that current
> thread will be rescheduled immediately after a sleep is irrelevant.
>
> >
> > If you have an alternate patch to try, we can test it. But since this
> > cond_resched() is needed anyway, I'm not sure it will change the result.
>
> schedule_timeout_killable(1) is an alternate patch to try; I don't think
> that this cond_resched() is needed anyway.
>
You are suggesting schedule_timeout_killable(1) in shrink_node_memcgs()?
next prev parent reply other threads:[~2020-03-11 22:14 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-10 21:39 [patch] mm, oom: prevent soft lockup on memcg oom for UP systems David Rientjes
2020-03-10 22:05 ` Tetsuo Handa
2020-03-10 22:55 ` David Rientjes
2020-03-11 9:34 ` Tetsuo Handa
2020-03-11 19:38 ` David Rientjes
2020-03-11 22:04 ` Tetsuo Handa
2020-03-11 22:14 ` David Rientjes [this message]
2020-03-12 0:12 ` Tetsuo Handa
2020-03-12 18:07 ` David Rientjes
2020-03-12 22:32 ` Andrew Morton
2020-03-16 9:31 ` Michal Hocko
2020-03-16 10:04 ` Tetsuo Handa
2020-03-16 10:14 ` Michal Hocko
2020-03-13 0:15 ` Tetsuo Handa
2020-03-13 22:01 ` David Rientjes
2020-03-13 23:15 ` Tetsuo Handa
2020-03-13 23:32 ` Tetsuo Handa
2020-03-16 23:59 ` David Rientjes
2020-03-17 3:18 ` Tetsuo Handa
2020-03-17 4:09 ` David Rientjes
2020-03-18 0:55 ` [patch v2] " David Rientjes
2020-03-18 9:42 ` Michal Hocko
2020-03-18 21:40 ` David Rientjes
2020-03-18 22:03 ` [patch v3] " David Rientjes
2020-03-19 7:09 ` Michal Hocko
2020-03-12 4:23 ` [patch] " Tetsuo Handa
2020-03-10 22:10 ` Michal Hocko
2020-03-10 23:02 ` David Rientjes
2020-03-11 8:27 ` Michal Hocko
2020-03-11 19:45 ` David Rientjes
2020-03-12 8:32 ` Michal Hocko
2020-03-12 18:20 ` David Rientjes
2020-03-12 20:16 ` Michal Hocko
2020-03-16 9:32 ` Michal Hocko
2020-03-11 0:18 ` Andrew Morton
2020-03-11 0:34 ` David Rientjes
2020-03-11 8:36 ` Michal Hocko
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