From d04e8acd03e5c3421ef18e3da7bc88d56179ca42 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Wed, 3 Jul 2013 15:02:03 -0700 Subject: [PATCH] mm: vmscan: treat pages marked for immediate reclaim as zone congestion Currently a zone will only be marked congested if the underlying BDI is congested but if dirty pages are spread across zones it is possible that an individual zone is full of dirty pages without being congested. The impact is that zone gets scanned very quickly potentially reclaiming really clean pages. This patch treats pages marked for immediate reclaim as congested for the purposes of marking a zone ZONE_CONGESTED and stalling in wait_iff_congested. Signed-off-by: Mel Gorman Cc: Johannes Weiner Cc: Michal Hocko Cc: Rik van Riel Cc: KAMEZAWA Hiroyuki Cc: Jiri Slaby Cc: Valdis Kletnieks Cc: Zlatko Calusic Cc: dormando Cc: Trond Myklebust Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 4898daf..bf47784 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -761,9 +761,15 @@ static unsigned long shrink_page_list(struct list_head *page_list, if (dirty && !writeback) nr_unqueued_dirty++; - /* Treat this page as congested if underlying BDI is */ + /* + * Treat this page as congested if the underlying BDI is or if + * pages are cycling through the LRU so quickly that the + * pages marked for immediate reclaim are making it to the + * end of the LRU a second time. + */ mapping = page_mapping(page); - if (mapping && bdi_write_congested(mapping->backing_dev_info)) + if ((mapping && bdi_write_congested(mapping->backing_dev_info)) || + (writeback && PageReclaim(page))) nr_congested++; /* -- 2.7.4