From 4bf2bba3750f10aa9e62e6949bc7e8329990f01b Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Wed, 11 Jul 2012 14:02:13 -0700 Subject: [PATCH] mm, thp: abort compaction if migration page cannot be charged to memcg If page migration cannot charge the temporary page to the memcg, migrate_pages() will return -ENOMEM. This isn't considered in memory compaction however, and the loop continues to iterate over all pageblocks trying to isolate and migrate pages. If a small number of very large memcgs happen to be oom, however, these attempts will mostly be futile leading to an enormous amout of cpu consumption due to the page migration failures. This patch will short circuit and fail memory compaction if migrate_pages() returns -ENOMEM. COMPACT_PARTIAL is returned in case some migrations were successful so that the page allocator will retry. Signed-off-by: David Rientjes Acked-by: Mel Gorman Cc: Minchan Kim Cc: Kamezawa Hiroyuki Cc: Rik van Riel Cc: Andrea Arcangeli Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/compaction.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/compaction.c b/mm/compaction.c index 7ea259d82a99..2f42d9528539 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -701,8 +701,11 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) if (err) { putback_lru_pages(&cc->migratepages); cc->nr_migratepages = 0; + if (err == -ENOMEM) { + ret = COMPACT_PARTIAL; + goto out; + } } - } out: