[CCing Dave, Ben]

Just a short summary as you were not on the CC list. This is sort of
follow up on https://lkml.org/lkml/2012/9/3/211. The end result is
slightly different because Tejun did a more generic cgroup solution (see
bellow). I cannot do the same for OpenSUSE so I will stick with the
memcg specific patch.

On Fri 14-09-12 17:03:06, Michal Hocko wrote:

I am currently planning to add a warning to most of the currenly
maintained distributions to have as big coverage as possible. No default
switch for obvious reasons but hopefuly we will get some feedback at
least.

Just for the record, I will post backports of the patch I ended up using
for openSUSE 11.4 and 12.[12] and SLES-SP2 as a reply to this email (and
2.6.32 in case somebody is interested).

I hope other distributions can either go with this (which will never be
merged but it should help to identify dubious usage of flat hierarchies
without a risk of breaking anythign) or what Tejun has in his tree[1]
8c7f6edb (cgroup: mark subsystems with broken hierarchy support and
whine if cgroups are nested for them) which is more generic but it is
also slightly more intrusive.

---
[1] - git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-3.7-hierarchy
-- 
Michal Hocko
SUSE Labs