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 <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 @@
struct zoneref *z;
struct zone *zone;
unsigned long writeback_threshold;
+ bool should_abort_reclaim;
get_mems_allowed();
delayacct_freepages_start();
@@ -2274,7 +2275,8 @@
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 @@
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;