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authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2017-07-06 15:40:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-06 16:24:35 -0700
commit8e675f7af50747e1e9e96538e8706767e4f80e2c (patch)
tree86820a752aa265ae2c118d86415ca03eed486691 /Documentation/cgroup-v2.txt
parent2262185c5b287f2758afda79c149b7cf6bee165c (diff)
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 <khlebnikov@yandex-team.ru> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Roman Guschin <guroan@gmail.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/cgroup-v2.txt')
-rw-r--r--Documentation/cgroup-v2.txt20
1 files changed, 16 insertions, 4 deletions
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