From 7056d3a37d2c6aaaab10c13e8e69adc67ec1fc65 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Fri, 28 Dec 2018 00:39:57 -0800 Subject: [PATCH] memcg, oom: notify on oom killer invocation from the charge path Burt Holzman has noticed that memcg v1 doesn't notify about OOM events via eventfd anymore. The reason is that 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the charge path") has moved the oom handling back to the charge path. While doing so the notification was left behind in mem_cgroup_oom_synchronize. Fix the issue by replicating the oom hierarchy locking and the notification. Link: http://lkml.kernel.org/r/20181224091107.18354-1-mhocko@kernel.org Fixes: 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the charge path") Signed-off-by: Michal Hocko Reported-by: Burt Holzman Acked-by: Johannes Weiner Cc: Vladimir Davydov [4.19+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4afd5971f2d4..af7f18b32389 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1673,6 +1673,9 @@ enum oom_status { static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) { + enum oom_status ret; + bool locked; + if (order > PAGE_ALLOC_COSTLY_ORDER) return OOM_SKIPPED; @@ -1707,10 +1710,23 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int return OOM_ASYNC; } + mem_cgroup_mark_under_oom(memcg); + + locked = mem_cgroup_oom_trylock(memcg); + + if (locked) + mem_cgroup_oom_notify(memcg); + + mem_cgroup_unmark_under_oom(memcg); if (mem_cgroup_out_of_memory(memcg, mask, order)) - return OOM_SUCCESS; + ret = OOM_SUCCESS; + else + ret = OOM_FAILED; - return OOM_FAILED; + if (locked) + mem_cgroup_oom_unlock(memcg); + + return ret; } /** -- 2.30.2