linux-kernel - Re: [RFC PATCH] mm, oom: disable dump

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Message-ID: <20190906110233.GE14491@dhcp22.suse.cz>
Date:   Fri, 6 Sep 2019 13:02:33 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Cc:     David Rientjes <rientjes@...gle.com>, linux-mm@...ck.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH] mm, oom: disable dump_tasks by default

On Fri 06-09-19 19:46:10, Tetsuo Handa wrote:
> On 2019/09/05 23:08, Michal Hocko wrote:
> > On Thu 05-09-19 22:39:47, Tetsuo Handa wrote:
> > [...]
> >> There is nothing that prevents users from enabling oom_dump_tasks by sysctl.
> >> But that requires a solution for OOM stalling problem.
> > 
> > You can hardly remove stalling if you are not reducing the amount of
> > output or get it into a different context. Whether the later is
> > reasonable is another question but you are essentially losing "at the
> > OOM event state".
> > 
> 
> I am not losing "at the OOM event state". Please find "struct oom_task_info"
> (for now) embedded into "struct task_struct" which holds "at the OOM event state".
> 
> And my patch moves "printk() from dump_tasks()" from OOM context to WQ context.

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Michal Hocko
SUSE Labs