cgroup: don't print subsystems for the default hierarchy
authorTejun Heo <tj@kernel.org>
Tue, 18 Aug 2015 20:58:16 +0000 (13:58 -0700)
committerTejun Heo <tj@kernel.org>
Tue, 18 Aug 2015 20:58:16 +0000 (13:58 -0700)
commitd98817d4961b9ef75062d1e129829d283b3dac57
treea71076ebe528096084a1290d823c0251691e9172
parent731a981e1059dd68c97212ccc9c0e1f169c1a77b
cgroup: don't print subsystems for the default hierarchy

It doesn't make sense to print subsystems on mount option or
/proc/PID/cgroup for the default hierarchy.

* cgroup.controllers file at the root of the default hierarchy lists
  the currently attached controllers.

* The default hierarchy is catch-all for unmounted subsystems.

* The default hierarchy doesn't accept any mount options.

Suppress subsystem printing on mount options and /proc/PID/cgroup for
the default hierarchy.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
kernel/cgroup.c