Re: [PATCH v5 11/18] sl[au]b: Allocate objects from memcg cache

From: JoonSoo Kim
Date: Mon Oct 29 2012 - 11:14:26 EST


Hi, Glauber.

2012/10/19 Glauber Costa <glommer@xxxxxxxxxxxxx>:
> We are able to match a cache allocation to a particular memcg. If the
> task doesn't change groups during the allocation itself - a rare event,
> this will give us a good picture about who is the first group to touch a
> cache page.
>
> This patch uses the now available infrastructure by calling
> memcg_kmem_get_cache() before all the cache allocations.
>
> Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
> CC: Christoph Lameter <cl@xxxxxxxxx>
> CC: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
> CC: Michal Hocko <mhocko@xxxxxxx>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> CC: Johannes Weiner <hannes@xxxxxxxxxxx>
> CC: Suleiman Souhlal <suleiman@xxxxxxxxxx>
> CC: Tejun Heo <tj@xxxxxxxxxx>
> ---
> include/linux/slub_def.h | 15 ++++++++++-----
> mm/memcontrol.c | 3 +++
> mm/slab.c | 6 +++++-
> mm/slub.c | 5 +++--
> 4 files changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
> index 961e72e..ed330df 100644
> --- a/include/linux/slub_def.h
> +++ b/include/linux/slub_def.h
> @@ -13,6 +13,8 @@
> #include <linux/kobject.h>
>
> #include <linux/kmemleak.h>
> +#include <linux/memcontrol.h>
> +#include <linux/mm.h>
>
> enum stat_item {
> ALLOC_FASTPATH, /* Allocation from cpu slab */
> @@ -209,14 +211,14 @@ static __always_inline int kmalloc_index(size_t size)
> * This ought to end up with a global pointer to the right cache
> * in kmalloc_caches.
> */
> -static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
> +static __always_inline struct kmem_cache *kmalloc_slab(gfp_t flags, size_t size)
> {
> int index = kmalloc_index(size);
>
> if (index == 0)
> return NULL;
>
> - return kmalloc_caches[index];
> + return memcg_kmem_get_cache(kmalloc_caches[index], flags);
> }

You don't need this,
because memcg_kmem_get_cache() is invoked in both slab_alloc() and
__cache_alloc_node().
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