From 7335084d446b83cbcb15da80497d03f0c1dc9e21 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 12 Jan 2012 17:19:33 -0800 Subject: [PATCH] mm: vmscan: do not OOM if aborting reclaim to start compaction During direct reclaim it is possible that reclaim will be aborted so that compaction can be attempted to satisfy a high-order allocation. If this decision is made before any pages are reclaimed, it is possible that 0 is returned to the page allocator potentially triggering an OOM. This has not been observed but it is a possibility so this patch addresses it. Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel Cc: Andrea Arcangeli Cc: Minchan Kim Cc: Dave Jones Cc: Jan Kara Cc: Andy Isaacson Cc: Nai Xia Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 866ab27..cb68c53 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2263,6 +2263,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, struct zoneref *z; struct zone *zone; unsigned long writeback_threshold; + bool should_abort_reclaim; get_mems_allowed(); delayacct_freepages_start(); @@ -2274,7 +2275,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, sc->nr_scanned = 0; if (!priority) disable_swap_token(sc->target_mem_cgroup); - if (shrink_zones(priority, zonelist, sc)) + should_abort_reclaim = shrink_zones(priority, zonelist, sc); + if (should_abort_reclaim) break; /* @@ -2342,6 +2344,10 @@ out: if (oom_killer_disabled) return 0; + /* Aborting reclaim to try compaction? don't OOM, then */ + if (should_abort_reclaim) + return 1; + /* top priority shrink_zones still had more to do? don't OOM, then */ if (global_reclaim(sc) && !all_unreclaimable(zonelist, sc)) return 1; -- 2.7.4