From 8e675f7af50747e1e9e96538e8706767e4f80e2c Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Thu, 6 Jul 2017 15:40:28 -0700 Subject: mm/oom_kill: count global and memory cgroup oom kills Show count of oom killer invocations in /proc/vmstat and count of processes killed in memory cgroup in knob "memory.events" (in memory.oom_control for v1 cgroup). Also describe difference between "oom" and "oom_kill" in memory cgroup documentation. Currently oom in memory cgroup kills tasks iff shortage has happened inside page fault. These counters helps in monitoring oom kills - for now the only way is grepping for magic words in kernel log. [akpm@linux-foundation.org: fix for mem_cgroup_count_vm_event() rename] [akpm@linux-foundation.org: fix comment, per Konstantin] Link: http://lkml.kernel.org/r/149570810989.203600.9492483715840752937.stgit@buzz Signed-off-by: Konstantin Khlebnikov Cc: Michal Hocko Cc: Tetsuo Handa Cc: Roman Guschin Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cgroup-v2.txt | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'Documentation/cgroup-v2.txt') diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index 5ac2fbde97e6..e6101976e0f1 100644 --- a/Documentation/cgroup-v2.txt +++ b/Documentation/cgroup-v2.txt @@ -852,13 +852,25 @@ PAGE_SIZE multiple when read back. The number of times the cgroup's memory usage was about to go over the max boundary. If direct reclaim - fails to bring it down, the OOM killer is invoked. + fails to bring it down, the cgroup goes to OOM state. oom - The number of times the OOM killer has been invoked in - the cgroup. This may not exactly match the number of - processes killed but should generally be close. + The number of time the cgroup's memory usage was + reached the limit and allocation was about to fail. + + Depending on context result could be invocation of OOM + killer and retrying allocation or failing alloction. + + Failed allocation in its turn could be returned into + userspace as -ENOMEM or siletly ignored in cases like + disk readahead. For now OOM in memory cgroup kills + tasks iff shortage has happened inside page fault. + + oom_kill + + The number of processes belonging to this cgroup + killed by any kind of OOM killer. memory.stat -- cgit v1.2.3