Re: [RFC][0/3] Virtual address space control for cgroups

From: Balbir Singh
Date: Mon Mar 17 2008 - 11:17:31 EST


Paul Menage wrote:
> On Mon, Mar 17, 2008 at 1:08 PM, Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>> I understand the per-mm pointer overhead back to the cgroup. I don't understand
>> the part about adding a per-mm pointer back to the "owning" task. We already
>> have task->mm.
>
> Yes, but we don't have mm->owner, which is what I was proposing -
> mm->owner would be a pointer typically to the mm's thread group
> leader. It would remove the need to have to have pointers for the
> various different cgroup subsystems that need to act on an mm rather
> than a task_struct, since then you could use
> mm->owner->cgroups[subsys_id].
>

Aaahh.. Yes.. mm->owner might be a good idea. The only thing we'll need to
handle is when mm->owner dies (I think the thread group is still kept around).
The other disadvantage is the double dereferencing, which should not be all that
bad.

> But this is kind of orthogonal to whether virtual address space limits
> should be a separate cgroup subsystem.
>

Yes, sure.


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