[Devel] Re: [PATCH 01/10] slab/slub: struct memcg_params

[Kirill A. Shutemov]

On Wed, Jul 25, 2012 at 06:38:12PM +0400, Glauber Costa wrote:
> For the kmem slab controller, we need to record some extra
> information in the kmem_cache structure.
> 
> Signed-off-by: Glauber Costa <glommer at parallels.com>
> Signed-off-by: Suleiman Souhlal <suleiman at google.com>
> CC: Christoph Lameter <cl at linux.com>
> CC: Pekka Enberg <penberg at cs.helsinki.fi>
> CC: Michal Hocko <mhocko at suse.cz>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> CC: Johannes Weiner <hannes at cmpxchg.org>
> ---
>  include/linux/slab.h     |    7 +++++++
>  include/linux/slab_def.h |    4 ++++
>  include/linux/slub_def.h |    3 +++
>  3 files changed, 14 insertions(+)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 0dd2dfa..3152bcd 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -177,6 +177,13 @@ unsigned int kmem_cache_size(struct kmem_cache *);
>  #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
>  #endif
>  
> +#ifdef CONFIG_MEMCG_KMEM
> +struct mem_cgroup_cache_params {
> +	struct mem_cgroup *memcg;
> +	int id;
> +};

IIUC, we only need the id to make slab name unique.  Why can't we embed
the id to struct mem_cgroup? Is it possible to have multiple slabs with
the same combination of type, size, and memcg?

-- 
 Kirill A. Shutemov