linux-kernel - Re: [PATCH] mm, oom: allow oom reaper to race with exit

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Message-ID: <20170725151500.GL26723@dhcp22.suse.cz>
Date:   Tue, 25 Jul 2017 17:15:01 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     "Kirill A. Shutemov" <kirill@...temov.name>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        David Rientjes <rientjes@...gle.com>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Oleg Nesterov <oleg@...hat.com>,
        Hugh Dickins <hughd@...gle.com>,
        Andrea Arcangeli <aarcange@...hat.com>, linux-mm@...ck.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm, oom: allow oom reaper to race with exit_mmap

On Tue 25-07-17 18:07:19, Kirill A. Shutemov wrote:
> On Tue, Jul 25, 2017 at 04:26:17PM +0200, Michal Hocko wrote:
[...]
> > Thanks for retesting Kirill. Are those numbers stable over runs? E.g.
> > the run without the patch has ~3% variance while the one with the patch
> > has it smaller. This sounds suspicious to me. There shouldn't be any
> > lock contention (except for the oom killer) so the lock shouldn't make
> > any difference wrt. variability.
> 
> There's run-to-tun variability. I'll post new numbers for your new test.

That's what I've seen and the variance was quite large. I suspected
shell but if you look at the more dedicated test, the std over avg is
still quite large.
-- 
Michal Hocko
SUSE Labs