linux-kernel - Re: [PATCH] vmscan: protect to read reclaim_stat by lru

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Date:	Fri, 9 Jul 2010 17:26:00 +0900
From:	Minchan Kim <minchan.kim@...il.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	Rik van Riel <riel@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] vmscan: protect to read reclaim_stat by lru_lock

On Fri, Jul 9, 2010 at 3:52 PM, KOSAKI Motohiro
<kosaki.motohiro@...fujitsu.com> wrote:
> Rik van Riel pointed out reading reclaim_stat should be protected
> lru_lock, otherwise vmscan might sweep 2x much pages.
>
> This fault was introduced by followint commit.
>
>  commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db
>  Author: Rik van Riel <riel@...hat.com>
>  Date:   Sat Oct 18 20:26:32 2008 -0700
>
>    vmscan: split LRU lists into anon & file sets
>
>    Split the LRU lists in two, one set for pages that are backed by real file
>    systems ("file") and one for pages that are backed by memory and swap
>    ("anon").  The latter includes tmpfs.
>
>    The advantage of doing this is that the VM will not have to scan over lots
>    of anonymous pages (which we generally do not want to swap out), just to
>    find the page cache pages that it should evict.
>
>    This patch has the infrastructure and a basic policy to balance how much
>    we scan the anon lists and how much we scan the file lists.  The big
>    policy changes are in separate patches.
>
> Cc: Rik van Riel <riel@...hat.com>
> Cc: Minchan Kim <minchan.kim@...il.com>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@...il.com>

Thanks, Kosaki. I have forgotten this issue.

-- 
Kind regards,
Minchan Kim
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