Re: [-mm] Add an owner to the mm_struct (v7)

[Balbir Singh <balbir@linux.vnet.ibm.com>]

Paul Menage wrote:
> On Thu, Apr 3, 2008 at 10:44 AM, Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>>  +
>>  +       /*
>>  +        * If there are other users of the mm and the owner (us) is exiting
>>  +        * we need to find a new owner to take on the responsibility.
>>  +        * When we use thread groups (CLONE_THREAD), the thread group
>>  +        * leader is kept around in zombie state, even after it exits.
>>  +        * delay_group_leader() ensures that if the group leader is around
>>  +        * we need not select a new owner.
>>  +        */
> 
> Hmm, is this new check for delay_group_leader() safe? Won't we have
> called exit_cgroup() by this point, and hence be reassigned to the
> root cgroup? And so mm->owner->cgroups won't point to the right place?
> 

cgroup_exit() comes in much later after exit_mm(). Moreover delay_group_leader()
is a function that checks to see if

We are the group leader and the thread group is not empty.

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL