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Message-ID: <20110428103126.GR4658@suse.de>
Date: Thu, 28 Apr 2011 11:31:26 +0100
From: Mel Gorman <mgorman@...e.de>
To: Minchan Kim <minchan.kim@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
linux-mm <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>,
Christoph Lameter <cl@...ux.com>,
Johannes Weiner <jweiner@...hat.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Rik van Riel <riel@...hat.com>,
Andrea Arcangeli <aarcange@...hat.com>
Subject: Re: [RFC 2/8] compaction: make isolate_lru_page with filter aware
On Wed, Apr 27, 2011 at 01:25:19AM +0900, Minchan Kim wrote:
> In async mode, compaction doesn't migrate dirty or writeback pages.
> So, it's meaningless to pick the page and re-add it to lru list.
>
> Of course, when we isolate the page in compaction, the page might
> be dirty or writeback but when we try to migrate the page, the page
> would be not dirty, writeback. So it could be migrated. But it's
> very unlikely as isolate and migration cycle is much faster than
> writeout.
>
> So, this patch helps cpu and prevent unnecessary LRU churning.
>
> Cc: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> Cc: Mel Gorman <mgorman@...e.de>
> Cc: Rik van Riel <riel@...hat.com>
> Cc: Andrea Arcangeli <aarcange@...hat.com>
> Signed-off-by: Minchan Kim <minchan.kim@...il.com>
Acked-by: Mel Gorman <mgorman@...e.de>
--
Mel Gorman
SUSE Labs
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