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

Kirill A. Shutemov
2012-07-26T10:01:11Z

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?

--
Kirill A. Shutemov