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

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

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