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From: Mel Gorman <mgorman@suse.de>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-mm@kvack.org, Kyungmin Park <kyungmin.park@samsung.com>
Subject: Re: [PATCH 2/2] mm: compaction: allow isolation of lower order buddy pages
Date: Tue, 10 Apr 2012 11:40:50 +0100	[thread overview]
Message-ID: <20120410104050.GF3789@suse.de> (raw)
In-Reply-To: <1333643534-1591-3-git-send-email-b.zolnierkie@samsung.com>

On Thu, Apr 05, 2012 at 06:32:13PM +0200, Bartlomiej Zolnierkiewicz wrote:
> Allow lower order buddy pages in suitable_migration_target()
> so isolate_freepages() can isolate them as free pages during
> compaction_alloc() phase.
> 
> Cc: Mel Gorman <mgorman@suse.de>
> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

Nak.

This patch depends on patch 1 to scan every page in isolate_freepages()
and I explained why that is a problem already. That aside, a side-effect
of this is that movable pages can get migrated to MIGRATE_UNMOVABLE
and MIGRATE_RECLAIMABLE pageblocks. This will have a negative impact on
fragmentation avoidance. In your particular use-case it will slightly
increase allocation success rates early in the lifetime of the system at
the cost of degrading success rates later.

-- 
Mel Gorman
SUSE Labs

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      parent reply	other threads:[~2012-04-10 10:40 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-05 16:32 [PATCH 0/2] mm: compaction: improve free pages selection Bartlomiej Zolnierkiewicz
2012-04-05 16:32 ` [PATCH 1/2] mm: compaction: try harder to isolate free pages Bartlomiej Zolnierkiewicz
2012-04-06  6:40   ` Minchan Kim
2012-04-06  8:21     ` Bartlomiej Zolnierkiewicz
2012-04-06  8:51       ` Minchan Kim
2012-04-10 10:38   ` Mel Gorman
2012-04-12  5:42     ` Mel Gorman
2012-04-05 16:32 ` [PATCH 2/2] mm: compaction: allow isolation of lower order buddy pages Bartlomiej Zolnierkiewicz
2012-04-05 21:46   ` David Rientjes
2012-04-06  8:38     ` Bartlomiej Zolnierkiewicz
2012-04-06  6:45   ` Minchan Kim
2012-04-10 10:40   ` Mel Gorman [this message]

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