Messages in this thread | | | Date | Tue, 01 Apr 2008 13:43:03 +0530 | From | Balbir Singh <> | Subject | Re: [RFC][-mm] Add an owner to the mm_struct (v3) |
| |
Balbir Singh wrote: > 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. > >
Thinking out aloud
If mm->owner changes and belongs to a different cgroup, we have a whole new problem. We need to determine all tasks that share the mm and belong to a particular cgroup, which changed since the new owner belongs to a different cgroup and then update the charge.
-- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL
| |