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 <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/compaction.c b/mm/compaction.c
index 7ea259d82a998c0397e976216ac861576e638100..2f42d952853970b5dd1f95a149d8750e7d570357 100644 (file)
--- 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: