On Tue, Nov 30, 2010 at 10:10:20AM +0900, KOSAKI Motohiro wrote: > > invalidate_mapping_pages is very big hint to reclaimer. > > It means user doesn't want to use the page any more. > > So in order to prevent working set page eviction, this patch > > move the page into tail of inactive list by PG_reclaim. > > > > Please, remember that pages in inactive list are working set > > as well as active list. If we don't move pages into inactive list's > > tail, pages near by tail of inactive list can be evicted although > > we have a big clue about useless pages. It's totally bad. > > > > Now PG_readahead/PG_reclaim is shared. > > fe3cba17 added ClearPageReclaim into clear_page_dirty_for_io for > > preventing fast reclaiming readahead marker page. > > > > In this series, PG_reclaim is used by invalidated page, too. > > If VM find the page is invalidated and it's dirty, it sets PG_reclaim > > to reclaim asap. Then, when the dirty page will be writeback, > > clear_page_dirty_for_io will clear PG_reclaim unconditionally. > > It disturbs this serie's goal. > > > > I think it's okay to clear PG_readahead when the page is dirty, not > > writeback time. So this patch moves ClearPageReadahead. > > > > Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx> > > Acked-by: Rik van Riel <riel@xxxxxxxxxx> > > Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx> > > Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> > > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > > Cc: Nick Piggin <npiggin@xxxxxxxxx> > > Cc: Mel Gorman <mel@xxxxxxxxx> > > I still dislike this one. I doubt this trick makes much benefit in real > world workload. > I would agree except as said elsewhere, it's a chicken and egg problem. We don't have a real world test because fadvise is not useful in its current iteration. I'm hoping that there will be a test comparing rsync on vanilla kernel rsync on patched kernel rsync+patch on vanilla kernel rsync+patch on patched kernel Are the results of such a test likely to happen? -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>