Re: [-mm] Add an owner to the mm_struct (v2)

Balbir Singh
2008-03-28T10:56:12Z

KAMEZAWA Hiroyuki wrote:
> On Fri, 28 Mar 2008 13:53:16 +0530
> Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>> -static struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
>> +struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
>> {
>> return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
>> struct mem_cgroup, css);
>> @@ -250,12 +250,17 @@ void mm_init_cgroup(struct mm_struct *mm
>>
>> mem = mem_cgroup_from_task(p);
>> css_get(&mem->css);
>> - mm->mem_cgroup = mem;
>> }
>>
>> void mm_free_cgroup(struct mm_struct *mm)
>> {
>> - css_put(&mm->mem_cgroup->css);
>> + struct mem_cgroup *mem;
>> +
>> + /*
>> + * TODO: Should we assign mm->owner to NULL here?
>> + */
>> + mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
>> + css_put(&mem->css);
>> }
>>
> How about changing this css_get()/css_put() from accounting against mm_struct
> to accouting against task_struct ?
> It seems simpler way after this mm->owner change.

But the reason why we account the mem_cgroup is that we don't want the
mem_cgroup to be deleted. I hope you meant mem_cgroup instead of mm_struct.

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