Re: [-mm] Add an owner to the mm_struct (v6)

From: Balbir Singh
Date: Thu Apr 03 2008 - 13:17:49 EST


Paul Menage wrote:
> On Thu, Apr 3, 2008 at 12:30 AM, Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>> + This option enables mm_struct's to have an owner. The advantage
>> + of this approach is that it allows for several independent memory
>> + based cgorup controllers to co-exist independently without too
>
> cgorup -> cgroup
>

yes, typo

>> + if (need_mm_owner_callback) {
>> + int i;
>> + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
>> + struct cgroup_subsys *ss = subsys[i];
>> + oldcgrp = task_cgroup(old, ss->subsys_id);
>> + newcgrp = task_cgroup(new, ss->subsys_id);
>> + if (oldcgrp == newcgrp)
>> + continue;
>> + if (ss->mm_owner_changed)
>> + ss->mm_owner_changed(ss, oldcgrp, newcgrp);
>
> Even better, maybe just pass in the relevant cgroup_subsys_state
> objects here, rather than the cgroup objects?
>

Is that better than passing the cgroups? All the callbacks I see usually pass
either task_struct or cgroup. Won't it be better, consistent use of API to pass
either of those?

>> css_get(&mem->css);
>> - rcu_assign_pointer(mm->mem_cgroup, mem);
>> css_put(&old_mem->css);
>
> These get/put calls are now unwanted?
>

Yes, will remove them

> Could you also add comments in mm_need_new_owner(), in particular the
> reason for checking for delay_group_leader() ?

Yep, will do

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