Masoud, will you try this patch? By the way, is /sys/fs/cgroup/memory/leaker/memory.usage_in_bytes remains non-zero despite /sys/fs/cgroup/memory/leaker/tasks became empty due to memcg OOM killer expected? Deleting big-data-file.bin after memcg OOM killer reduces some, but still remains non-zero. ---------------------------------------- >From 2f92c70f390f42185c6e2abb8dda98b1b7d02fa9 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Date: Sun, 4 Aug 2019 00:41:30 +0900 Subject: [PATCH] memcg, oom: don't require __GFP_FS when invoking memcg OOM killer Masoud Sharbiani noticed that commit 29ef680ae7c21110 ("memcg, oom: move out_of_memory back to the charge path") broke memcg OOM called from __xfs_filemap_fault() path. It turned out that try_chage() is retrying forever without making forward progress because mem_cgroup_oom(GFP_NOFS) cannot invoke the OOM killer due to commit 3da88fb3bacfaa33 ("mm, oom: move GFP_NOFS check to out_of_memory"). Regarding memcg OOM, we need to bypass GFP_NOFS check in order to guarantee forward progress. Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Reported-by: Masoud Sharbiani <msharbiani@xxxxxxxxx> Bisected-by: Masoud Sharbiani <msharbiani@xxxxxxxxx> Fixes: 29ef680ae7c21110 ("memcg, oom: move out_of_memory back to the charge path") --- mm/oom_kill.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index eda2e2a..26804ab 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -1068,9 +1068,10 @@ bool out_of_memory(struct oom_control *oc) * The OOM killer does not compensate for IO-less reclaim. * pagefault_out_of_memory lost its gfp context so we have to * make sure exclude 0 mask - all other users should have at least - * ___GFP_DIRECT_RECLAIM to get here. + * ___GFP_DIRECT_RECLAIM to get here. But mem_cgroup_oom() has to + * invoke the OOM killer even if it is a GFP_NOFS allocation. */ - if (oc->gfp_mask && !(oc->gfp_mask & __GFP_FS)) + if (oc->gfp_mask && !(oc->gfp_mask & __GFP_FS) && !is_memcg_oom(oc)) return true; /* -- 1.8.3.1