From: Johannes Weiner <[email protected]>
Subject: mm: memcg: do not declare OOM from __GFP_NOFAIL allocations
84235de394d9 ("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]>
---
mm/memcontrol.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN
mm/memcontrol.c~mm-memcg-do-not-declare-oom-from-__gfp_nofail-allocations
mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcg-do-not-declare-oom-from-__gfp_nofail-allocations
+++ a/mm/memcontrol.c
@@ -2696,6 +2696,9 @@ static int __mem_cgroup_try_charge(struc
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
_
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