docs/cgroup: Add the list of threaded controllers to cgroup-v2.rst

The cgroup-v2 file mentions the concept of threaded controllers which can
be used in a threaded cgroup. However, it doesn't mention clearly which
controllers are threaded leading to some confusion about what controller
can be used requiring some experimentation. Clear this up by explicitly
listing the controllers that can be used currently in a threaded cgroup.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index e40b8560e0020dcabf0d7032e6647a1f6003bd01..e440aee4fe94860a9a2656d999de21dd38637762 100644 (file)
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -364,6 +364,13 @@ constraint, a threaded controller must be able to handle competition
 between threads in a non-leaf cgroup and its child cgroups.  Each
 threaded controller defines how such competitions are handled.
 
+Currently, the following controllers are threaded and can be enabled
+in a threaded cgroup::
+
+- cpu
+- cpuset
+- perf_event
+- pids
 
 [Un]populated Notification
 --------------------------