From: Mel Gorman <mel@csn.ul.ie>
To: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Christoph Lameter <cl@linux-foundation.org>,
Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>,
David Rientjes <rientjes@google.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 03/12] mm: Share the anon_vma ref counts between KSM and page migration
Date: Sat, 20 Feb 2010 09:29:21 +0000 [thread overview]
Message-ID: <20100220092921.GH1445@csn.ul.ie> (raw)
In-Reply-To: <4B7F29CD.1050703@redhat.com>
On Fri, Feb 19, 2010 at 07:16:13PM -0500, Rik van Riel wrote:
> On 02/19/2010 04:58 PM, Mel Gorman wrote:
>
>> external_refcount is about as good as I can think of to explain what's
>> going on :/
>
> Sounds "good" to me. Much better than giving the wrong
> impression that this is the only refcount for the anon_vma.
>
Have renamed it so. If/when this all gets merged, I'll look into what's
required to make this a "real" refcount rather than the existing locking
mechanism. I'm very wary though because even with your anon_vma changes to
avoid excessive sharing, a refcount in there that is used in all paths might
become a hotly contended cache line. i.e. it might look nice, but it might
be a performance hit. It needs to be done carefully and as a separate
series.
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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next prev parent reply other threads:[~2010-02-20 9:29 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-18 18:02 [PATCH 0/12] Memory Compaction v3 Mel Gorman
2010-02-18 18:02 ` [PATCH 01/12] mm,migration: Take a reference to the anon_vma before migrating Mel Gorman
2010-02-19 0:12 ` KAMEZAWA Hiroyuki
2010-02-19 13:59 ` Mel Gorman
2010-02-19 16:43 ` Rik van Riel
2010-02-18 18:02 ` [PATCH 02/12] mm,migration: Do not try to migrate unmapped anonymous pages Mel Gorman
2010-02-19 16:45 ` Rik van Riel
2010-02-18 18:02 ` [PATCH 03/12] mm: Share the anon_vma ref counts between KSM and page migration Mel Gorman
2010-02-19 0:18 ` KAMEZAWA Hiroyuki
2010-02-19 14:05 ` Mel Gorman
2010-02-19 15:01 ` Christoph Lameter
2010-02-20 3:48 ` KAMEZAWA Hiroyuki
2010-02-20 9:32 ` Mel Gorman
2010-02-19 5:09 ` Minchan Kim
2010-02-19 21:42 ` Rik van Riel
2010-02-19 21:58 ` Mel Gorman
2010-02-20 0:16 ` Rik van Riel
2010-02-20 9:29 ` Mel Gorman [this message]
2010-02-18 18:02 ` [PATCH 04/12] mm: Document /proc/pagetypeinfo Mel Gorman
2010-02-19 1:36 ` Minchan Kim
2010-02-19 21:42 ` Rik van Riel
2010-02-18 18:02 ` [PATCH 05/12] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA or memory hot-remove Mel Gorman
2010-02-19 0:21 ` KAMEZAWA Hiroyuki
2010-02-19 14:09 ` Mel Gorman
2010-02-18 18:02 ` [PATCH 06/12] Export unusable free space index via /proc/pagetypeinfo Mel Gorman
2010-02-19 1:35 ` Minchan Kim
2010-02-19 21:46 ` Rik van Riel
2010-02-18 18:02 ` [PATCH 07/12] Export fragmentation " Mel Gorman
2010-02-19 1:59 ` Minchan Kim
2010-02-20 0:16 ` Rik van Riel
2010-02-18 18:02 ` [PATCH 08/12] Memory compaction core Mel Gorman
2010-02-19 0:37 ` KAMEZAWA Hiroyuki
2010-02-19 14:15 ` Mel Gorman
2010-02-18 18:02 ` [PATCH 09/12] Add /proc trigger for memory compaction Mel Gorman
2010-02-19 0:43 ` KAMEZAWA Hiroyuki
2010-02-19 14:16 ` Mel Gorman
2010-02-20 3:53 ` KAMEZAWA Hiroyuki
2010-02-19 2:26 ` Minchan Kim
2010-02-18 18:02 ` [PATCH 10/12] Add /sys trigger for per-node " Mel Gorman
2010-02-19 14:53 ` Greg KH
2010-02-19 15:28 ` Mel Gorman
2010-02-19 15:31 ` Greg KH
2010-02-19 15:51 ` Mel Gorman
2010-02-19 15:52 ` Mel Gorman
2010-02-19 16:02 ` Greg KH
2010-02-18 18:02 ` [PATCH 11/12] Direct compact when a high-order allocation fails Mel Gorman
2010-02-19 0:51 ` KAMEZAWA Hiroyuki
2010-02-19 14:19 ` Mel Gorman
2010-02-19 2:41 ` Minchan Kim
2010-02-19 14:25 ` Mel Gorman
2010-02-18 18:02 ` [PATCH 12/12] Do not compact within a preferred zone after a compaction failure Mel Gorman
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