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Date: Tue, 10 Jul 2018 14:12:28 -0700 (PDT)
From: David Rientjes <rientjes@google.com>
Subject: Re: [PATCH] mm, oom: remove sleep from under oom_lock
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References: <20180709074706.30635-1-mhocko@kernel.org> <alpine.DEB.2.21.1807091548280.125566@chino.kir.corp.google.com> <20180710094341.GD14284@dhcp22.suse.cz> <alpine.DEB.2.21.1807101152410.9234@chino.kir.corp.google.com>
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To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>

On Tue, 10 Jul 2018, David Rientjes wrote:

> I think it's better, thanks.  However, does it address the question about 
> why __oom_reap_task_mm() needs oom_lock protection?  Perhaps it would be 
> helpful to mention synchronization between reaping triggered from 
> oom_reaper and by exit_mmap().
> 

Actually, can't we remove the need to take oom_lock in exit_mmap() if 
__oom_reap_task_mm() can do a test and set on MMF_UNSTABLE and, if already 
set, bail out immediately?