The patch titled
Subject: mm/memcg: add group_oom_kill memory event
has been added to the -mm tree. Its filename is
mm-add-group_oom_kill-memory-event.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-add-group_oom_kill-memory-event.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-add-group_oom_kill-memory-event.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dan Schatzberg <schatzberg.dan@xxxxxxxxx>
Subject: mm/memcg: add group_oom_kill memory event
Our container agent wants to know when a container exits if it was OOM
killed or not to report to the user. We use memory.oom.group = 1 to
ensure that OOM kills within the container's cgroup kill everything.
Existing memory.events are insufficient for knowing if this triggered:
1) Our current approach reads memory.events oom_kill and reports the
container was killed if the value is non-zero. This is erroneous in
some cases where containers create their children cgroups with
memory.oom.group=1 as such OOM kills will get counted against the
container cgroup's oom_kill counter despite not actually OOM killing
the entire container.
2) Reading memory.events.local will fail to identify OOM kills in leaf
cgroups (that don't set memory.oom.group) within the container cgroup.
This patch adds a new oom_group_kill event when memory.oom.group triggers
to allow userspace to cleanly identify when an entire cgroup is oom
killed.
Link: https://lkml.kernel.org/r/20211203162426.3375036-1-schatzberg.dan@xxxxxxxxx
Signed-off-by: Dan Schatzberg <schatzberg.dan@xxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Zefan Li <lizefan.x@xxxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Alex Shi <alexs@xxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/cgroup-v2.rst | 4 ++++
include/linux/memcontrol.h | 1 +
mm/memcontrol.c | 5 +++++
mm/oom_kill.c | 1 +
4 files changed, 11 insertions(+)
--- a/Documentation/admin-guide/cgroup-v2.rst~mm-add-group_oom_kill-memory-event
+++ a/Documentation/admin-guide/cgroup-v2.rst
@@ -1268,6 +1268,10 @@ PAGE_SIZE multiple when read back.
The number of processes belonging to this cgroup
killed by any kind of OOM killer.
+ oom_group_kill
+ The number of times all tasks in the cgroup were killed
+ due to memory.oom.group.
+
memory.events.local
Similar to memory.events but the fields in the file are local
to the cgroup i.e. not hierarchical. The file modified event
--- a/include/linux/memcontrol.h~mm-add-group_oom_kill-memory-event
+++ a/include/linux/memcontrol.h
@@ -42,6 +42,7 @@ enum memcg_memory_event {
MEMCG_MAX,
MEMCG_OOM,
MEMCG_OOM_KILL,
+ MEMCG_OOM_GROUP_KILL,
MEMCG_SWAP_HIGH,
MEMCG_SWAP_MAX,
MEMCG_SWAP_FAIL,
--- a/mm/memcontrol.c~mm-add-group_oom_kill-memory-event
+++ a/mm/memcontrol.c
@@ -4390,6 +4390,9 @@ static int mem_cgroup_oom_control_read(s
seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
seq_printf(sf, "oom_kill %lu\n",
atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
+ seq_printf(sf, "oom_group_kill %lu\n",
+ atomic_long_read(
+ &memcg->memory_events[MEMCG_OOM_GROUP_KILL]));
return 0;
}
@@ -6318,6 +6321,8 @@ static void __memory_events_show(struct
seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
seq_printf(m, "oom_kill %lu\n",
atomic_long_read(&events[MEMCG_OOM_KILL]));
+ seq_printf(m, "oom_group_kill %lu\n",
+ atomic_long_read(&events[MEMCG_OOM_GROUP_KILL]));
}
static int memory_events_show(struct seq_file *m, void *v)
--- a/mm/oom_kill.c~mm-add-group_oom_kill-memory-event
+++ a/mm/oom_kill.c
@@ -994,6 +994,7 @@ static void oom_kill_process(struct oom_
* If necessary, kill all tasks in the selected memory cgroup.
*/
if (oom_group) {
+ memcg_memory_event(oom_group, MEMCG_OOM_GROUP_KILL);
mem_cgroup_print_oom_group(oom_group);
mem_cgroup_scan_tasks(oom_group, oom_kill_memcg_member,
(void *)message);
_
Patches currently in -mm which might be from schatzberg.dan@xxxxxxxxx are
mm-add-group_oom_kill-memory-event.patch
