From: Mel Gorman <mgorman@suse.de>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Kyungmin Park <kmpark@infradead.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Michal Nazarewicz <mina86@mina86.com>,
Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration
Date: Tue, 11 Sep 2012 09:59:49 +0100 [thread overview]
Message-ID: <20120911085948.GF11266@suse.de> (raw)
In-Reply-To: <1347324112-14134-1-git-send-email-minchan@kernel.org>
On Tue, Sep 11, 2012 at 09:41:52AM +0900, Minchan Kim wrote:
> This patch drops clean cache pages instead of migration during
> alloc_contig_range() to minimise allocation latency by reducing the amount
> of migration is necessary. It's useful for CMA because latency of migration
> is more important than evicting the background processes working set.
> In addition, as pages are reclaimed then fewer free pages for migration
> targets are required so it avoids memory reclaiming to get free pages,
> which is a contributory factor to increased latency.
>
> * from v1
> * drop migrate_mode_t
> * add reclaim_clean_pages_from_list instad of MIGRATE_DISCARD support - Mel
>
> I measured elapsed time of __alloc_contig_migrate_range which migrates
> 10M in 40M movable zone in QEMU machine.
>
> Before - 146ms, After - 7ms
>
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Cc: Michal Nazarewicz <mina86@mina86.com>
> Cc: Rik van Riel <riel@redhat.com>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
> Signed-off-by: Minchan Kim <minchan@kernel.org>
My signed-off is already on this but in earlier versions I was still
asking for changes. This time the patch looks good to me so even though
it is a bit redundant.
Reviewed-by: Mel Gorman <mgorman@suse.de>
Thanks Minchan.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2012-09-11 8:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-11 0:41 [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration Minchan Kim
2012-09-11 8:59 ` Mel Gorman [this message]
2012-09-11 11:15 ` Michal Nazarewicz
2012-09-11 11:23 ` Kyungmin Park
2012-09-12 20:07 ` Andrew Morton
2012-09-12 23:58 ` Minchan Kim
2012-09-13 19:17 ` Geert Uytterhoeven
2012-09-13 22:19 ` Andrew Morton
2012-09-14 0:10 ` Minchan Kim
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