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authorVladimir Davydov <vdavydov@parallels.com>2015-02-13 01:59:20 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-13 05:54:09 +0300
commitf7ce3190c4a35bf887adb7a1aa1ba899b679872d (patch)
tree8a40d93f1e796e1007d59e67541ce3044430b927 /mm/memcontrol.c
parent49e7e7ff8d551b5b1e2f8da8497b9058cfa25672 (diff)
downloadlinux-f7ce3190c4a35bf887adb7a1aa1ba899b679872d.tar.xz
slab: embed memcg_cache_params to kmem_cache
Currently, kmem_cache stores a pointer to struct memcg_cache_params instead of embedding it. The rationale is to save memory when kmem accounting is disabled. However, the memcg_cache_params has shrivelled drastically since it was first introduced: * Initially: struct memcg_cache_params { bool is_root_cache; union { struct kmem_cache *memcg_caches[0]; struct { struct mem_cgroup *memcg; struct list_head list; struct kmem_cache *root_cache; bool dead; atomic_t nr_pages; struct work_struct destroy; }; }; }; * Now: struct memcg_cache_params { bool is_root_cache; union { struct { struct rcu_head rcu_head; struct kmem_cache *memcg_caches[0]; }; struct { struct mem_cgroup *memcg; struct kmem_cache *root_cache; }; }; }; So the memory saving does not seem to be a clear win anymore. OTOH, keeping a pointer to memcg_cache_params struct instead of embedding it results in touching one more cache line on kmem alloc/free hot paths. Besides, it makes linking kmem caches in a list chained by a field of struct memcg_cache_params really painful due to a level of indirection, while I want to make them linked in the following patch. That said, let us embed it. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index afa55bb38cbd..6f3c0fcd7a2d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -332,7 +332,7 @@ struct mem_cgroup {
struct cg_proto tcp_mem;
#endif
#if defined(CONFIG_MEMCG_KMEM)
- /* Index in the kmem_cache->memcg_params->memcg_caches array */
+ /* Index in the kmem_cache->memcg_params.memcg_caches array */
int kmemcg_id;
#endif
@@ -531,7 +531,7 @@ static void disarm_sock_keys(struct mem_cgroup *memcg)
#ifdef CONFIG_MEMCG_KMEM
/*
- * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
+ * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
* The main reason for not using cgroup id for this:
* this works better in sparse environments, where we have a lot of memcgs,
* but only a few kmem-limited. Or also, if we have, for instance, 200
@@ -2667,8 +2667,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep)
struct mem_cgroup *memcg;
struct kmem_cache *memcg_cachep;
- VM_BUG_ON(!cachep->memcg_params);
- VM_BUG_ON(!cachep->memcg_params->is_root_cache);
+ VM_BUG_ON(!is_root_cache(cachep));
if (current->memcg_kmem_skip_account)
return cachep;
@@ -2702,7 +2701,7 @@ out:
void __memcg_kmem_put_cache(struct kmem_cache *cachep)
{
if (!is_root_cache(cachep))
- css_put(&cachep->memcg_params->memcg->css);
+ css_put(&cachep->memcg_params.memcg->css);
}
/*
@@ -2778,7 +2777,7 @@ struct mem_cgroup *__mem_cgroup_from_kmem(void *ptr)
if (PageSlab(page)) {
cachep = page->slab_cache;
if (!is_root_cache(cachep))
- memcg = cachep->memcg_params->memcg;
+ memcg = cachep->memcg_params.memcg;
} else
/* page allocated by alloc_kmem_pages */
memcg = page->mem_cgroup;