[Devel] Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache

[Glauber Costa]

On 09/24/2012 09:56 PM, Tejun Heo wrote:
> Hello, Glauber.
> 
> On Mon, Sep 24, 2012 at 12:46:35PM +0400, Glauber Costa wrote:
>>>> +#ifdef CONFIG_MEMCG_KMEM
>>>> +	/* Slab accounting */
>>>> +	struct kmem_cache *slabs[MAX_KMEM_CACHE_TYPES];
>>>> +#endif
>>>
>>> Bah, 400 entry array in struct mem_cgroup.  Can't we do something a
>>> bit more flexible?
>>>
>>
>> I guess. I still would like it to be an array, so we can easily access
>> its fields. There are two ways around this:
>>
>> 1) Do like the events mechanism and allocate this in a separate
>> structure. Add a pointer chase in the access, and I don't think it helps
>> much because it gets allocated anyway. But we could at least
>> defer it to the time when we limit the cache.
> 
> Start at some reasonable size and then double it as usage grows?  How
> many kmem_caches do we typically end up using?
> 

So my Fedora box here, recently booted on a Fedora kernel, will have 111
caches. How would 150 sound to you?