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Date: Tue, 30 Jan 2018 09:54:45 +0100
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: [patch -mm v2 2/3] mm, memcg: replace cgroup aware oom killer
 mount option with tunable
Message-ID: <20180130085445.GQ21609@dhcp22.suse.cz>
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To: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, David Rientjes <rientjes@google.com>, Roman Gushchin <guro@fb.com>, Vladimir Davydov <vdavydov.dev@gmail.com>, Johannes Weiner <hannes@cmpxchg.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, kernel-team@fb.com, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org

On Mon 29-01-18 11:11:39, Tejun Heo wrote:
> Hello, Michal.
> 
> On Mon, Jan 29, 2018 at 11:46:57AM +0100, Michal Hocko wrote:
> > @@ -1292,7 +1292,11 @@ the memory controller considers only cgroups belonging to the sub-tree
> >  of the OOM'ing cgroup.
> >  
> >  The root cgroup is treated as a leaf memory cgroup, so it's compared
> > -with other leaf memory cgroups and cgroups with oom_group option set.
> > +with other leaf memory cgroups and cgroups with oom_group option
> > +set. Due to internal implementation restrictions the size of the root
> > +cgroup is a cumulative sum of oom_badness of all its tasks (in other
> > +words oom_score_adj of each task is obeyed). This might change in the
> > +future.
> 
> Thanks, we can definitely use more documentation.  However, it's a bit
> difficult to follow.  Maybe expand it to a separate paragraph on the
> current behavior with a clear warning that the default OOM heuristics
> is subject to changes?

Does this sound any better?