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From: Rik van Riel <riel@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>,
	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>,
	Minchan Kim <minchan.kim@gmail.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 03/14] mm: Share the anon_vma ref counts between KSM and page migration
Date: Tue, 06 Apr 2010 20:10:23 -0400	[thread overview]
Message-ID: <4BBBCD6F.3050707@redhat.com> (raw)
In-Reply-To: <20100406170528.ecb30941.akpm@linux-foundation.org>

On 04/06/2010 08:05 PM, Andrew Morton wrote:
> On Fri,  2 Apr 2010 17:02:37 +0100
> Mel Gorman<mel@csn.ul.ie>  wrote:

>> +#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
>> +
>> +	/*
>> +	 * The external_refcount is taken by either KSM or page migration
>> +	 * to take a reference to an anon_vma when there is no
>> +	 * guarantee that the vma of page tables will exist for
>> +	 * the duration of the operation. A caller that takes
>> +	 * the reference is responsible for clearing up the
>> +	 * anon_vma if they are the last user on release
>> +	 */
>> +	atomic_t external_refcount;
>>   #endif
>
> hah.

>> +	anonvma_external_refcount_init(anon_vma);
>
> What a mouthful.  Can we do s/external_//g?

For the function, sure.

However, I believe it would be good to keep the variable
inside the anon_vma as "external_refcount", because the
VMAs attached to the anon_vma take a reference by being
on the list (and leave the refcount alone).

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  reply	other threads:[~2010-04-07  0:11 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-02 16:02 [PATCH 0/14] Memory Compaction v7 Mel Gorman
2010-04-02 16:02 ` [PATCH 01/14] mm,migration: Take a reference to the anon_vma before migrating Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07  9:56     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 02/14] mm,migration: Do not try to migrate unmapped anonymous pages Mel Gorman
2010-04-02 16:02 ` [PATCH 03/14] mm: Share the anon_vma ref counts between KSM and page migration Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07  0:10     ` Rik van Riel [this message]
2010-04-07 10:01     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 04/14] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA or memory hot-remove Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07 10:22     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 05/14] Export unusable free space index via /proc/unusable_index Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07 10:35     ` Mel Gorman
2010-04-13 12:42     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 06/14] Export fragmentation index via /proc/extfrag_index Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07 10:46     ` Mel Gorman
2010-04-13 12:43     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 07/14] Move definition for LRU isolation modes to a header Mel Gorman
2010-04-02 16:02 ` [PATCH 08/14] Memory compaction core Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07 15:21     ` Mel Gorman
2010-04-08 16:59   ` Mel Gorman
2010-04-08 17:06     ` Andrea Arcangeli
2010-04-02 16:02 ` [PATCH 09/14] Add /proc trigger for memory compaction Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07 15:39     ` Mel Gorman
2010-04-07 18:27       ` Mel Gorman
2010-04-02 16:02 ` [PATCH 10/14] Add /sys trigger for per-node " Mel Gorman
2010-04-07  0:05   ` Andrew Morton
2010-04-07  0:31     ` KAMEZAWA Hiroyuki
2010-04-06 21:56       ` Andrew Morton
2010-04-07  1:19         ` KAMEZAWA Hiroyuki
2010-04-07 15:42     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 11/14] Direct compact when a high-order allocation fails Mel Gorman
2010-04-07  0:06   ` Andrew Morton
2010-04-07 16:06     ` Mel Gorman
2010-04-07 18:29     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 12/14] Add a tunable that decides when memory should be compacted and when it should be reclaimed Mel Gorman
2010-04-07  0:06   ` Andrew Morton
2010-04-07 16:11     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 13/14] Do not compact within a preferred zone after a compaction failure Mel Gorman
2010-04-07  0:06   ` Andrew Morton
2010-04-07  0:55     ` Andrea Arcangeli
2010-04-07 16:32     ` Mel Gorman
2010-04-02 16:02 ` [PATCH 14/14] mm,migration: Allow the migration of PageSwapCache pages Mel Gorman
2010-04-06  6:54   ` KAMEZAWA Hiroyuki
2010-04-06 15:37   ` Minchan Kim
2010-04-07  0:06   ` Andrew Morton
2010-04-07 16:49     ` Mel Gorman
2010-04-06 14:47 ` [PATCH 0/14] Memory Compaction v7 Tarkan Erimer
2010-04-06 15:00   ` Mel Gorman
2010-04-06 15:03     ` Tarkan Erimer
  -- strict thread matches above, loose matches on Subject: below --
2010-03-30  9:14 [PATCH 0/14] Memory Compaction v6 Mel Gorman
2010-03-30  9:14 ` [PATCH 03/14] mm: Share the anon_vma ref counts between KSM and page migration Mel Gorman

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