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authorMel Gorman <mgorman@suse.de>2013-07-03 15:02:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 16:07:29 -0700
commitd04e8acd03e5c3421ef18e3da7bc88d56179ca42 (patch)
tree7183adb0d45168268289f38751be4f508544947b
parent8e950282804558e4605401b9c79c1d34f0d73507 (diff)
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 <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmscan.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4898daf074cf..bf4778479e3a 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++;
/*