From: Li Zefan <lizefan@huawei.com>
Date: Thu, 5 Jun 2014 09:16:30 +0000 (+0800)
Subject: cgroup: disallow disabled controllers on the default hierarchy
X-Git-Tag: omap-for-v3.16/fixes-against-rc1~81^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c731ae1d0f02a300697a8b1564780ad28a6c2013;p=pandora-kernel.git

cgroup: disallow disabled controllers on the default hierarchy

After booting with cgroup_disable=memory, I still saw memcg files
in the default hierarchy, and I can write to them, though it won't
take effect.

  # dmesg
  ...
  Disabling memory control group subsystem
  ...
  # mount -t cgroup -o __DEVEL__sane_behavior xxx /cgroup
  # ls /cgroup
  ...
  memory.failcnt                   memory.move_charge_at_immigrate
  memory.force_empty               memory.numa_stat
  memory.limit_in_bytes            memory.oom_control
  ...
  # cat /cgroup/memory.usage_in_bytes
  0

tj: Minor comment update.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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