mm: memcontrol: reclaim at least once for __GFP_NORETRY

Currently, __GFP_NORETRY tries charging once and gives up before even
trying to reclaim.  Bring the behavior on par with the page allocator
and reclaim at least once before giving up.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

@@ -2613,13 +2613,13 @@ static int mem_cgroup_try_charge(struct mem_cgroup *memcg,
 	if (!(gfp_mask & __GFP_WAIT))
 		goto nomem;
 
-	if (gfp_mask & __GFP_NORETRY)
-		goto nomem;
-
 	nr_reclaimed = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
 
 	if (mem_cgroup_margin(mem_over_limit) >= batch)
 		goto retry;
+
+	if (gfp_mask & __GFP_NORETRY)
+		goto nomem;
 	/*
 	 * Even though the limit is exceeded at this point, reclaim
 	 * may have been able to free some pages.  Retry the charge