[PATCH cgroup/for-4.15-fixes] cgroup: add warning about RT not being supported on cgroup2

[Tejun Heo]

From: Tejun Heo <tj@xxxxxxxxxx>
Date: Tue, 5 Dec 2017 09:10:17 -0800

We haven't yet figured out what to do with RT threads on cgroup2.
Document the limitation.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx>
---
 Documentation/cgroup-v2.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 779211f..55a28f4 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -898,6 +898,10 @@ controller implements weight and absolute bandwidth limit models for
 normal scheduling policy and absolute bandwidth allocation model for
 realtime scheduling policy.
 
+WARNING: cgroup2 doesn't yet support control of realtime processes and
+the cpu controller can only be enabled when all RT processes are in
+the root cgroup.
+
 
 CPU Interface Files
 ~~~~~~~~~~~~~~~~~~~
-- 
2.9.5