Commit 1f14c1ac authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: memcg: do not allow task about to OOM kill to bypass the limit

Commit 49426420

 ("mm: memcg: handle non-error OOM situations more
gracefully") allowed tasks that already entered a memcg OOM condition to
bypass the memcg limit on subsequent allocation attempts hoping this
would expedite finishing the page fault and executing the kill.

David Rientjes is worried that this breaks memcg isolation guarantees
and since there is no evidence that the bypass actually speeds up fault
processing just change it so that these subsequent charge attempts fail
outright.  The notable exception being __GFP_NOFAIL charges which are
required to bypass the limit regardless.
Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reported-by: default avatarDavid Rientjes <rientjes@google.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-bt: David Rientjes <rientjes@google.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 96f1c58d
......@@ -2694,7 +2694,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
goto bypass;
if (unlikely(task_in_memcg_oom(current)))
goto bypass;
goto nomem;
if (gfp_mask & __GFP_NOFAIL)
oom = false;
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment