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Date: Tue, 06 Nov 2012 14:41:13 -0500
From: Rik van Riel <riel@redhat.com>
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To: Mel Gorman <mgorman@suse.de>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Andrea Arcangeli <aarcange@redhat.com>, Ingo Molnar <mingo@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>, Hugh Dickins <hughd@google.com>,
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        Andrew Morton <akpm@linux-foundation.org>,
        Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 15/19] mm: numa: Add fault driven placement and migration
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On 11/06/2012 04:14 AM, Mel Gorman wrote:
> From: Peter Zijlstra <a.p.zijlstra@chello.nl>
>
> NOTE: This patch is based on "sched, numa, mm: Add fault driven
> 	placement and migration policy" but as it throws away all the policy
> 	to just leave a basic foundation I had to drop the signed-offs-by.
>
> This patch creates a bare-bones method for setting PTEs pte_numa in the
> context of the scheduler that when faulted later will be faulted onto the
> node the CPU is running on.  In itself this does nothing useful but any
> placement policy will fundamentally depend on receiving hints on placement
> from fault context and doing something intelligent about it.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>

Excellent basis for implementing a smarter NUMA
policy.

Not sure if such a policy should be implemented
as a replacement for this patch, or on top of it...

Either way, thank you for cleaning up all of the
NUMA base code, while I was away at conferences
and stuck in airports :)

Peter, Andrea - does this look like a good basis
for implementing and comparing your NUMA policies?

I mean, it does to me. I am just wondering if there
is any reason at all you two could not use it as a
basis for an apples-to-apples comparison of your
NUMA placement policies?

Sharing 2/3 of the code would sure get rid of the
bulk of the discussion, and allow us to make real
progress.