Date: Thu, 7 Sep 2017 15:52:39 +0100
From: Roman Gushchin <guro@fb.com>
To: Christopher Lameter <cl@linux.com>
CC: David Rientjes <rientjes@google.com>, <nzimmer@sgi.com>,
        <holt@sgi.com>, Michal Hocko <mhocko@kernel.org>, <linux-mm@kvack.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Andrew Morton <akpm@linux-foundation.org>, Tejun Heo <tj@kernel.org>,
        <kernel-team@fb.com>, <cgroups@vger.kernel.org>,
        <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <sivanich@sgi.com>
Subject: Re: [v7 5/5] mm, oom: cgroup v2 mount option to disable cgroup-aware
 OOM killer
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On Thu, Sep 07, 2017 at 09:43:30AM -0500, Christopher Lameter wrote:
> On Wed, 6 Sep 2017, David Rientjes wrote:
> 
> > > The oom_kill_allocating_task sysctl which causes the OOM killer
> > > to simple kill the allocating task is useless. Killing the random
> > > task is not the best idea.
> > >
> > > Nobody likes it, and hopefully nobody uses it.
> > > We want to completely deprecate it at some point.
> > >
> >
> > SGI required it when it was introduced simply to avoid the very expensive
> > tasklist scan.  Adding Christoph Lameter to the cc since he was involved
> > back then.
> 
> Really? From what I know and worked on way back when: The reason was to be
> able to contain the affected application in a cpuset. Multiple apps may
> have been running in multiple cpusets on a large NUMA machine and the OOM
> condition in one cpuset should not affect the other. It also helped to
> isolate the application behavior causing the oom in numerous cases.
> 
> Doesnt this requirement transfer to cgroups in the same way?

We have per-node memory stats and plan to use them during the OOM victim
selection. Hopefully it can help.

> 
> Left SGI in 2008 so adding Dimitri who may know about the current
> situation. Robin Holt also left SGI as far as I know.

Thanks!