linux-kernel - Re: [patch v2] mm, oom: fix concurrent munlock and oom reaper unmap

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Message-ID: <alpine.DEB.2.21.1804191212530.157851@chino.kir.corp.google.com>
Date:   Thu, 19 Apr 2018 12:14:04 -0700 (PDT)
From:   David Rientjes <rientjes@...gle.com>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
cc:     mhocko@...nel.org, akpm@...ux-foundation.org, aarcange@...hat.com,
        guro@...com, linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [patch v2] mm, oom: fix concurrent munlock and oom reaper
 unmap

On Thu, 19 Apr 2018, Tetsuo Handa wrote:

> current code has a possibility that the OOM reaper is disturbed by
> unpredictable dependencies, like I worried that
> 
>   I think that there is a possibility that the OOM reaper tries to reclaim
>   mlocked pages as soon as exit_mmap() cleared VM_LOCKED flag by calling
>   munlock_vma_pages_all().
> 
> when current approach was proposed.

That's exactly the issue that this patch is fixing, yes.  If you brought 
that possibility up then I'm sorry that it was ignored.