From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Kirill A. Shutemov" <kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>
Subject: Re: [PATCH 02/10] consider a memcg parameter in kmem_create_cache
Date: Thu, 26 Jul 2012 13:01:11 +0300
Message-ID: <20120726100111.GA7447@shutemov.name>
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To: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Christoph Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>, David Rientjes <rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Pekka Enberg <penberg-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Greg Thelen <gthelen-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, Frederic Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Pekka Enberg <penberg-bbCR+/B0CizivPeTLB3BmA@public.gmane.org>, Kamezawa Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>, Suleiman Souhlal <suleiman-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>

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