Re: [RFC][mm] [PATCH 4/4] Memory cgroup hierarchy feature selector (v2)

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

Li Zefan wrote:
>> +static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
>> +					u64 val)
>> +{
>> +	int retval = 0;
>> +	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
>> +
>> +	if (val == 1) {
>> +		if (list_empty(&cont->children))
> 
> cgroup_lock should be held before checking cont->children.
> 

Good point, I'll look at that aspect

>> +			mem->use_hierarchy = val;
>> +		else
>> +			retval = -EBUSY;
>> +	} else if (val == 0) {
> 
> And code duplicate.

Yes, this can be optimized better. I'll fix that in v3.

> 
>> +		if (list_empty(&cont->children))
>> +			mem->use_hierarchy nn= val;
>> +		else
>> +			retval = -EBUSY;
>> +	} else
>> +		retval = -EINVAL;
>> +
>> +	return retval;
>> +}
>> +
> 


-- 
	Balbir