Messages in this thread | | | Date | Tue, 11 Sep 2012 09:59:49 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration |
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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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