3.12-stable review patch. If anyone has any objections, please let me know.
------------------ From: Johannes Weiner <[email protected]> commit 1f14c1ac19aa45118054b6d5425873c5c7fc23a1 upstream. Commit 4942642080ea ("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: Johannes Weiner <[email protected]> Reported-by: David Rientjes <[email protected]> Acked-by: Michal Hocko <[email protected]> Acked-bt: David Rientjes <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2675,7 +2675,7 @@ static int __mem_cgroup_try_charge(struc goto bypass; if (unlikely(task_in_memcg_oom(current))) - goto bypass; + goto nomem; if (gfp_mask & __GFP_NOFAIL) oom = false; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
