1 files changed, 19 insertions, 3 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index b6dfa0081a8e..8e645ee52045 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -91,6 +91,9 @@ struct scan_control {
         /* Can pages be swapped as part of reclaim? */
         unsigned int may_swap:1;
 
+        /* Can cgroups be reclaimed below their normal consumption range? */
+        unsigned int may_thrash:1;
+
         unsigned int hibernation_mode:1;
 
         /* One of the zones is ready for compaction */
@@ -2294,6 +2297,12 @@ static bool shrink_zone(struct zone *zone, struct scan_control *sc,
                         struct lruvec *lruvec;
                         int swappiness;
 
+                        if (mem_cgroup_low(root, memcg)) {
+                                if (!sc->may_thrash)
+                                        continue;
+                                mem_cgroup_events(memcg, MEMCG_LOW, 1);
+                        }
+
                         lruvec = mem_cgroup_zone_lruvec(zone, memcg);
                         swappiness = mem_cgroup_swappiness(memcg);
 
@@ -2315,8 +2324,7 @@ static bool shrink_zone(struct zone *zone, struct scan_control *sc,
                                 mem_cgroup_iter_break(root, memcg);
                                 break;
                         }
-                        memcg = mem_cgroup_iter(root, memcg, &reclaim);
-                } while (memcg);
+                } while ((memcg = mem_cgroup_iter(root, memcg, &reclaim)));
 
                 /*
                  * Shrink the slab caches in the same proportion that
@@ -2519,10 +2527,11 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
                                           struct scan_control *sc)
 {
+        int initial_priority = sc->priority;
         unsigned long total_scanned = 0;
         unsigned long writeback_threshold;
         bool zones_reclaimable;
-
+retry:
         delayacct_freepages_start();
 
         if (global_reclaim(sc))
@@ -2572,6 +2581,13 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
         if (sc->compaction_ready)
                 return 1;
 
+        /* Untapped cgroup reserves?  Don't OOM, retry. */
+        if (!sc->may_thrash) {
+                sc->priority = initial_priority;
+                sc->may_thrash = 1;
+                goto retry;
+        }
+
         /* Any of the zones still reclaimable?  Don't OOM. */
         if (zones_reclaimable)
                 return 1;