[v11 5/6] mm, oom: add cgroup v2 mount option for cgroup-aware OOM killer

Roman Gushchin
2017-10-05T13:04:53Z

Add a "groupoom" cgroup v2 mount option to enable the cgroup-aware
OOM killer. If not set, the OOM selection is performed in
a "traditional" per-process way.

The behavior can be changed dynamically by remounting the cgroupfs.

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com
Cc: cgroups@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
include/linux/cgroup-defs.h | 5 +++++
kernel/cgroup/cgroup.c | 10 ++++++++++
mm/memcontrol.c | 3 +++
3 files changed, 18 insertions(+)

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 3e55bbd31ad1..cae5343a8b21 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -80,6 +80,11 @@ enum {
* Enable cpuset controller in v1 cgroup to use v2 behavior.
*/
CGRP_ROOT_CPUSET_V2_MODE = (1 << 4),
+
+ /*
+ * Enable cgroup-aware OOM killer.
+ */
+ CGRP_GROUP_OOM = (1 << 5),
};

/* cftype->flags */
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index c3421ee0d230..8d8aa46ff930 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1709,6 +1709,9 @@ static int parse_cgroup_root_flags(char *data, unsigned int *root_flags)
if (!strcmp(token, "nsdelegate")) {
*root_flags |= CGRP_ROOT_NS_DELEGATE;
continue;
+ } else if (!strcmp(token, "groupoom")) {
+ *root_flags |= CGRP_GROUP_OOM;
+ continue;
}

pr_err("cgroup2: unknown option \"%s\"\n", token);
@@ -1725,6 +1728,11 @@ static void apply_cgroup_root_flags(unsigned int root_flags)
cgrp_dfl_root.flags |= CGRP_ROOT_NS_DELEGATE;
else
cgrp_dfl_root.flags &= ~CGRP_ROOT_NS_DELEGATE;
+
+ if (root_flags & CGRP_GROUP_OOM)
+ cgrp_dfl_root.flags |= CGRP_GROUP_OOM;
+ else
+ cgrp_dfl_root.flags &= ~CGRP_GROUP_OOM;
}
}

@@ -1732,6 +1740,8 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root
{
if (cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE)
seq_puts(seq, ",nsdelegate");
+ if (cgrp_dfl_root.flags & CGRP_GROUP_OOM)
+ seq_puts(seq, ",groupoom");
return 0;
}

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d5acb278b11a..fe6155d827c1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2866,6 +2866,9 @@ bool mem_cgroup_select_oom_victim(struct oom_control *oc)
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return false;

+ if (!(cgrp_dfl_root.flags & CGRP_GROUP_OOM))
+ return false;
+
if (oc->memcg)
root = oc->memcg;
else
--
2.13.6

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