[Devel] Re: [PATCH 02/10] consider a memcg parameter in kmem_create_cache

[Glauber Costa]

On 07/26/2012 02:01 PM, Kirill A. Shutemov wrote:
> On Thu, Jul 26, 2012 at 01:42:05PM +0400, Glauber Costa wrote:
>> On 07/25/2012 10:10 PM, Kirill A. Shutemov wrote:
>>> On Wed, Jul 25, 2012 at 06:38:13PM +0400, Glauber Costa wrote:
>>>
>>> ...
>>>
>>>> @@ -337,6 +341,12 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
>>>>  	__kmalloc(size, flags)
>>>>  #endif /* DEBUG_SLAB */
>>>>  
>>>> +#ifdef CONFIG_MEMCG_KMEM
>>>> +#define MAX_KMEM_CACHE_TYPES 400
>>>> +#else
>>>> +#define MAX_KMEM_CACHE_TYPES 0
>>>> +#endif /* CONFIG_MEMCG_KMEM */
>>>> +
>>>>  #ifdef CONFIG_NUMA
>>>>  /*
>>>>   * kmalloc_node_track_caller is a special version of kmalloc_node that
>>>
>>> ...
>>>
>>>> @@ -527,6 +532,24 @@ static inline bool memcg_kmem_enabled(struct mem_cgroup *memcg)
>>>>  		memcg->kmem_accounted;
>>>>  }
>>>>  
>>>> +struct ida cache_types;
>>>> +
>>>> +void memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *cachep)
>>>> +{
>>>> +	int id = -1;
>>>> +
>>>> +	if (!memcg)
>>>> +		id = ida_simple_get(&cache_types, 0, MAX_KMEM_CACHE_TYPES,
>>>> +				    GFP_KERNEL);
>>>
>>> MAX_KMEM_CACHE_TYPES is 0 if CONFIG_MEMCG_KMEM undefined.
>>> If 'end' parameter of ida_simple_get() is 0 it will use default max value
>>> which is 0x80000000.
>>> I guess you want MAX_KMEM_CACHE_TYPES to be 1 for !CONFIG_MEMCG_KMEM.
>>>
>> ida_simple_get will not, and should never be called for !CONFIG_MEMCG_KMEM.
> 
> Okay. Is there an user for MAX_KMEM_CACHE_TYPES if !CONFIG_MEMCG_KMEM?
> 

Actually, not anymore. I will just remove it then, instead of forcing it
to 0.

Thanks!