Hello, Vivek.

On Fri, Sep 14, 2012 at 02:07:54PM -0400, Vivek Goyal wrote:

I am curious that why are you planning to provide capability of controller
specific view of hierarchy. To me it sounds pretty close to having
separate hierarchies per controller. Just that it is a little more
restricted configuration. 

I think it's a lot less crazy and gives us a way to bind a resource to
a set of controller cgroups regardless which task is looking at it,
which is something we're sorely missing now.

IOW, who is is the user of this functionality and who is asking for it.
Can we go all out where all controllers have only one hierarchy view.

I think the issue is that controllers inherently have overhead and
behavior alterations depending on the tree organization.  At least
from the usage I see from google which uses nested cgroups
extensively, at least that level of flexibility seems necessary.

In addition, for some resources, granularity beyond certain point
simply doesn't work.  Per-service granularity might make sense for cpu
but applying it by default would be silly for blkio.

Thanks.

-- 
tejun