mm: memcg: do not declare OOM from __GFP_NOFAIL allocations

Commit 84235de ("fs: buffer: move allocation failure loop into the allocator") started recognizing __GFP_NOFAIL in memory cgroups but forgot to disable the OOM killer. Any task that does not fail allocation will also not enter the OOM completion path. So don't declare an OOM state in this case or it'll be leaked and the task be able to bypass the limit until the next userspace-triggered page fault cleans up the OOM state. Reported-by: William Dauchy <[email protected]> Signed-off-by: Johannes Weiner <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: David Rientjes <[email protected]> Cc: <[email protected]> [3.12.x] Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
alberto-fc · Dec 13, 2013 · a0d8b00 · a0d8b00
1 parent f40386a
commit a0d8b00
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
@@ -2696,6 +2696,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 	if (unlikely(task_in_memcg_oom(current)))
 		goto bypass;
 
+	if (gfp_mask & __GFP_NOFAIL)
+		oom = false;
+
 	/*
 	 * We always charge the cgroup the mm_struct belongs to.
 	 * The mm_struct's mem_cgroup changes on task migration if the