cgroup: notify ns_cgroup deprecated

The ns_cgroup will be removed very soon.  Let's warn, for this version,
ns_cgroup is deprecated.

Make ns_cgroup and clone_children exclusive.  If the clone_children is set
and the ns_cgroup is mounted, let's fail with EINVAL when the ns_cgroup
subsys is created (a printk will help the user to understand why the
creation fails).

Update the feature remove schedule file with the deprecated ns_cgroup.

Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index d2af87ba96e1..f3da8c0a3af2 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -526,6 +526,23 @@ Who:	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
 
 ----------------------------
 
+What:   namespace cgroup (ns_cgroup)
+When:   2.6.38
+Why:    The ns_cgroup leads to some problems:
+        * cgroup creation is out-of-control
+        * cgroup name can conflict when pids are looping
+        * it is not possible to have a single process handling
+        a lot of namespaces without falling in a exponential creation time
+        * we may want to create a namespace without creating a cgroup
+
+        The ns_cgroup is replaced by a compatibility flag 'clone_children',
+        where a newly created cgroup will copy the parent cgroup values.
+        The userspace has to manually create a cgroup and add a task to
+        the 'tasks' file.
+Who:    Daniel Lezcano <daniel.lezcano@free.fr>
+
+----------------------------
+
 What:   iwlwifi disable_hw_scan module parameters
 When:   2.6.40
 Why:    Hareware scan is the prefer method for iwlwifi devices for