Re: [RFC][-mm] Add an owner to the mm_struct (v3)

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

Paul Menage wrote:
> On Mon, Mar 31, 2008 at 11:23 PM, Balbir Singh
> <balbir@linux.vnet.ibm.com> wrote:
>>  > Here we'll want to call vm_cgroup_update_mm_owner(), to adjust the
>>  > accounting. (Or if in future we end up with more than a couple of
>>  > subsystems that want notification at this time, we'll want to call
>>  > cgroup_update_mm_owner() and have it call any interested subsystems.
>>  >
>>
>>  I don't think we need to adjust accounting, since only mm->owner is changing and
>>  not the cgroup to which the task/mm belongs. Do we really need to notify? I
>>  don't want to do any notifications under task_lock().
> 
> It's possible but unlikely that the new owner is in a different cgroup.

Hmmm... that can never happen with thread groups, since mm->owner is
p->group_leader and that never exits unless all threads are gone (it can
explicitly change groups though). Without thread groups, the new owner can
belong to a different cgroup, so we might need notification.


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