linux-kernel - Re: [patch v4] mm, oom: fix unnecessary killing of additional processes

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Message-ID: <alpine.DEB.2.21.1807241722580.49968@chino.kir.corp.google.com>
Date:   Tue, 24 Jul 2018 17:24:31 -0700 (PDT)
From:   David Rientjes <rientjes@...gle.com>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org
Subject: Re: [patch v4] mm, oom: fix unnecessary killing of additional
 processes

On Wed, 25 Jul 2018, Tetsuo Handa wrote:

> > If exit_mmap() gets preempted indefinitely before it can free any memory, 
> > we are better off oom killing another process.  The purpose of the timeout 
> > is to give an oom victim an amount of time to free its memory and exit 
> > before selecting another victim.
> > 
> 
> There is no point with emitting the noise.
> 

If you're concerned about too many printk's to the kernel log, 
oom_reap_task_mm() could store whether MMF_UNSTABLE was set or not before 
attempting to reap and then only printk if this was the first oom reaping.

We lose the ability to determine if subsequent reaps freed additional 
memory, but I don't suppose that's too concerning.