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Date: Wed, 3 Feb 2016 15:57:51 -0800 (PST)
From: David Rientjes <rientjes@google.com>
Subject: Re: [PATCH 2/5] oom reaper: handle mlocked pages
In-Reply-To: <1454505240-23446-3-git-send-email-mhocko@kernel.org>
Message-ID: <alpine.DEB.2.10.1602031557320.10331@chino.kir.corp.google.com>
References: <1454505240-23446-1-git-send-email-mhocko@kernel.org> <1454505240-23446-3-git-send-email-mhocko@kernel.org>
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To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, Oleg Nesterov <oleg@redhat.com>, Linus Torvalds <torvalds@linux-foundation.org>, Hugh Dickins <hughd@google.com>, Andrea Argangeli <andrea@kernel.org>, Rik van Riel <riel@redhat.com>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>, Michal Hocko <mhocko@suse.com>

On Wed, 3 Feb 2016, Michal Hocko wrote:

> From: Michal Hocko <mhocko@suse.com>
> 
> __oom_reap_vmas current skips over all mlocked vmas because they need a
> special treatment before they are unmapped. This is primarily done for
> simplicity. There is no reason to skip over them and reduce the amount
> of reclaimed memory. This is safe from the semantic point of view
> because try_to_unmap_one during rmap walk would keep tell the reclaim
> to cull the page back and mlock it again.
> 
> munlock_vma_pages_all is also safe to be called from the oom reaper
> context because it doesn't sit on any locks but mmap_sem (for read).
> 
> Signed-off-by: Michal Hocko <mhocko@suse.com>

Acked-by: David Rientjes <rientjes@google.com>

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