Re: [PATCH 09/23] kmem slab accounting basic infrastructure

[Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>]

>> @@ -3951,8 +3966,26 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
>>                         break;
>>                 if (type == _MEM)
>>                         ret = mem_cgroup_resize_limit(memcg, val);
>> -               else
>> +               else if (type == _MEMSWAP)
>>                         ret = mem_cgroup_resize_memsw_limit(memcg, val);
>> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
>> +               else if (type == _KMEM) {
>> +                       ret = res_counter_set_limit(&memcg->kmem, val);
>> +                       if (ret)
>> +                               break;
>> +                       /*
>> +                        * Once enabled, can't be disabled. We could in theory
>> +                        * disable it if we haven't yet created any caches, or
>> +                        * if we can shrink them all to death.
>> +                        *
>> +                        * But it is not worth the trouble
>> +                        */
>> +                       if (!memcg->kmem_accounted&&  val != RESOURCE_MAX)
>> +                               memcg->kmem_accounted = true;
>> +               }
>> +#endif
>> +               else
>> +                       return -EINVAL;
>>                 break;
>>         case RES_SOFT_LIMIT:
>>                 ret = res_counter_memparse_write_strategy(buffer,&val);
>
> Why is RESOURCE_MAX special?

Because I am using the convention that setting it to any value different 
than that will enable accounting.