memcg: prevent endless loop when charging huge pages

[linux-2.6-block.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 79abb1fd39d29c2f59515c5b59d74a02102ea421..50eb50e100fd19fa683e57041be3835e5b072f84 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1837,8 +1837,15 @@ static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
                flags |= MEM_CGROUP_RECLAIM_NOSWAP;
        } else
                mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
-
-       if (csize > PAGE_SIZE) /* change csize and retry */
+       /*
+        * csize can be either a huge page (HPAGE_SIZE), a batch of
+        * regular pages (CHARGE_SIZE), or a single regular page
+        * (PAGE_SIZE).
+        *
+        * Never reclaim on behalf of optional batching, retry with a
+        * single page instead.
+        */
+       if (csize == CHARGE_SIZE)
                return CHARGE_RETRY;
 
        if (!(gfp_mask & __GFP_WAIT))