[RFD][PATCH] memcg: Move Usage at Task Move

[KAMEZAWA Hiroyuki]

On Thu, 12 Jun 2008 16:08:12 -0500
"Serge E. Hallyn" <serue at us.ibm.com> wrote:

> > Assume a thread group contains threadA, threadB, threadC.
> > 
> > I wanted to ask "Can threadA, and threadB, and threadC
> > be in different cgroups ? And if so, how ns cgroup handles it ?"
> > 
> > Maybe I don't understand ns cgroup.
> 
> In part yes, but nonetheless a very interesting question when it comes
> to composition of cgroups!
> 
> Yes, you can have threads in different cgroups.  The ns cgroup just
> tracks nsproxy unshares.  So if you run the attached program and look
> around, you'll see the first thread is in /cg/taskpid while the second
> one is in /cg/taskpid/secondthreadpid.
> 
> Clearly, composing this with a cgroup which needs to keep threads in the
> same cgroup becomes problematic!
> 
> Interesting :)
> 

Thank you for kindly explanation. I'll take this into account. I confirmed
memory resouce controller should not get tasks's cgroup directly from "task"
and should get it from "mm->owner".

Thank you.

Regards,
-Kame