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Message-ID: <1350657519.2768.27.camel@twins>
Subject: Re: [tip:numa/core] sched/numa/mm: Improve migration
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: linux-tip-commits@vger.kernel.org, linux-kernel@vger.kernel.org,
        hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org,
        akpm@linux-foundation.org, mgorman@suse.de, tglx@linutronix.de
Date: Fri, 19 Oct 2012 16:38:39 +0200
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	 <20121019135122.GI31863@cmpxchg.org>
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On Fri, 2012-10-19 at 09:51 -0400, Johannes Weiner wrote:
> Right now, unlike the traditional migration path, this breaks COW for
> every migration, but maybe you don't care about shared pages in the
> first place.  And fixing that should be nothing more than grabbing the
> anon_vma lock and using rmap to switch more than one pmd over, right?
> 

This patch was very much about getting _something_ rather than caring
(too much) about all the weird corner cases.

And yes, your suggestion sounds about right.