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@xxxxxxxxxxx> > Cc: Michal Nazarewicz <mina86@xxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> 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@xxxxxxx> Thanks Minchan. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>