2 files changed, 19 insertions, 6 deletions

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index c07f7b4fb88d..71c4da413444 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -466,6 +466,10 @@ Note:
 5.3 swappiness
 
 Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
+Please note that unlike the global swappiness, memcg knob set to 0
+really prevents from any swapping even if there is a swap storage
+available. This might lead to memcg OOM killer if there are no file
+pages to reclaim.
 
 Following cgroups' swappiness can't be changed.
 - root cgroup (uses /proc/sys/vm/swappiness).
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7acf43bf04a2..93a7e36ded89 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1452,17 +1452,26 @@ static int mem_cgroup_count_children(struct mem_cgroup *memcg)
 static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
 {
         u64 limit;
-        u64 memsw;
 
         limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
-        limit += total_swap_pages << PAGE_SHIFT;
 
-        memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
         /*
-         * If memsw is finite and limits the amount of swap space available
-         * to this memcg, return that limit.
+         * Do not consider swap space if we cannot swap due to swappiness
          */
-        return min(limit, memsw);
+        if (mem_cgroup_swappiness(memcg)) {
+                u64 memsw;
+
+                limit += total_swap_pages << PAGE_SHIFT;
+                memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+
+                /*
+                 * If memsw is finite and limits the amount of swap space
+                 * available to this memcg, return that limit.
+                 */
+                limit = min(limit, memsw);
+        }
+
+        return limit;
 }
 
 void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,