memcg: clarify use_hierarchy documentation
The memcg code does not allow changing memory.use_hierarchy if the
parent cgroup has enabled use_hierarchy. Update documentation to match
the code.
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 7781857..b6ed61c9 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -485,8 +485,9 @@
# echo 0 > memory.use_hierarchy
-NOTE1: Enabling/disabling will fail if the cgroup already has other
- cgroups created below it.
+NOTE1: Enabling/disabling will fail if either the cgroup already has other
+ cgroups created below it, or if the parent cgroup has use_hierarchy
+ enabled.
NOTE2: When panic_on_oom is set to "2", the whole system will panic in
case of an OOM event in any cgroup.