Subject: [PATCH v4 2/2] memcg: add oom_kill_inherit event indicator

From: chengkaitao <[email protected]>

Oom_kill_inherit can reflect the number of child cgroups selected by
the parent cgroup's OOM killer. We can refer to the proportion of the
indicator to adjust the value of oom_protect. The larger oom_protect,
the smaller oom_kill_inherit.

Signed-off-by: chengkaitao <[email protected]>
---
Documentation/admin-guide/cgroup-v2.rst | 4 ++++
include/linux/memcontrol.h | 1 +
mm/memcontrol.c | 6 ++++++
3 files changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 51e9a84d508a..e6f56443d049 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1358,6 +1358,10 @@ PAGE_SIZE multiple when read back.
The number of processes belonging to this cgroup
killed by any kind of OOM killer.

+ oom_kill_inherit
+ The number of processes belonging to this cgroup
+ killed by all Ancestral memcg's OOM killer.
+
oom_group_kill
The number of times a group OOM has occurred.

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 23ea28d98c0e..d7797f9a0605 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -46,6 +46,7 @@ enum memcg_memory_event {
MEMCG_MAX,
MEMCG_OOM,
MEMCG_OOM_KILL,
+ MEMCG_OOM_INHERIT,
MEMCG_OOM_GROUP_KILL,
MEMCG_SWAP_HIGH,
MEMCG_SWAP_MAX,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8ee67abb415f..cf3cacf26cec 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2129,6 +2129,10 @@ struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,

if (memcg == oom_domain)
break;
+ /* we use oom.group's logic to update the OOM_INHERIT indicator,
+ * but OOM_INHERIT and oom.group are independent of each other.
+ */
+ memcg_memory_event(memcg, MEMCG_OOM_INHERIT);
}

if (oom_group)
@@ -6622,6 +6626,8 @@ static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
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_kill_inherit %lu\n",
+ atomic_long_read(&events[MEMCG_OOM_INHERIT]));
seq_printf(m, "oom_group_kill %lu\n",
atomic_long_read(&events[MEMCG_OOM_GROUP_KILL]));
}
--
2.14.1