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authorMinchan Kim <minchan.kim@gmail.com>2011-10-31 17:06:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-10-31 17:30:44 -0700
commit39deaf8585152f1a35c1676d3d7dc6ae0fb65967 (patch)
treea7509ea61c2f1028ed7ef961aa1abd16d50905f9 /mm/vmscan.c
parent4356f21d09283dc6d39a6f7287a65ddab61e2808 (diff)
mm: compaction: make isolate_lru_page() filter-aware
In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu overhead and prevent unnecessary LRU churning. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ec6dbcb976d..c007e78d707 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1045,6 +1045,9 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
ret = -EBUSY;
+ if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page)))
+ return ret;
+
if (likely(get_page_unless_zero(page))) {
/*
* Be careful not to clear PageLRU until after we're