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Message-ID: <5252BECA.4080302@redhat.com>
Date: Mon, 07 Oct 2013 10:01:46 -0400
From: Rik van Riel <riel@redhat.com>
MIME-Version: 1.0
Subject: Re: [PATCH 06/63] mm: Prevent parallel splits during THP migration
References: <1381141781-10992-1-git-send-email-mgorman@suse.de> <1381141781-10992-7-git-send-email-mgorman@suse.de>
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To: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, Srikar Dronamraju <srikar@linux.vnet.ibm.com>, Ingo Molnar <mingo@kernel.org>, Andrea Arcangeli <aarcange@redhat.com>, Johannes Weiner <hannes@cmpxchg.org>, Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>

On 10/07/2013 06:28 AM, Mel Gorman wrote:
> THP migrations are serialised by the page lock but on its own that does
> not prevent THP splits. If the page is split during THP migration then
> the pmd_same checks will prevent page table corruption but the unlock page
> and other fix-ups potentially will cause corruption. This patch takes the
> anon_vma lock to prevent parallel splits during migration.
> 
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Mel Gorman <mgorman@suse.de>

Acked-by: Rik van Riel <riel@redhat.com>

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