[PATCH -mm 09/14] memcg: rename some cache id related variables

Vladimir Davydov
2014-09-21T15:14:41Z

memcg_limited_groups_array_size, which defines the size of memcg_caches
arrays, sounds rather cumbersome. Also it doesn't point anyhow that it's
related to kmem/caches stuff. So let's rename it to memcg_max_cache_ids.
It's concise and points us directly to memcg_cache_id.

Also, rename kmem_limited_groups to memcg_cache_ida, because it's not a
container for groups, but the memcg_cache_id allocator.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
---
include/linux/memcontrol.h | 9 ++++++++-
mm/memcontrol.c | 19 +++++++++----------
mm/slab_common.c | 4 ++--
3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e57a097cf393..7c1bf0a84950 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -415,7 +415,12 @@ static inline void sock_release_memcg(struct sock *sk)
#ifdef CONFIG_MEMCG_KMEM
extern struct static_key memcg_kmem_enabled_key;

-extern int memcg_limited_groups_array_size;
+/*
+ * The maximal number of kmem-active memory cgroups that can exist on the
+ * system. May grow, but never shrinks. The value returned by memcg_cache_id()
+ * is always less.
+ */
+extern int memcg_max_cache_ids;

static inline bool memcg_kmem_enabled(void)
{
@@ -545,6 +550,8 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
return __memcg_kmem_get_cache(cachep, gfp);
}
#else
+#define memcg_max_cache_ids 0
+
static inline bool memcg_kmem_enabled(void)
{
return false;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d665d715090b..0020824dee96 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -615,12 +615,11 @@ static void disarm_sock_keys(struct mem_cgroup *memcg)
* memcgs, and none but the 200th is kmem-limited, we'd have to have a
* 200 entry array for that.
*
- * The current size of the caches array is stored in
- * memcg_limited_groups_array_size. It will double each time we have to
- * increase it.
+ * The current size of the caches array is stored in memcg_max_cache_ids. It
+ * will double each time we have to increase it.
*/
-static DEFINE_IDA(kmem_limited_groups);
-int memcg_limited_groups_array_size;
+static DEFINE_IDA(memcg_cache_ida);
+int memcg_max_cache_ids;

/*
* MIN_SIZE is different than 1, because we would like to avoid going through
@@ -2926,12 +2925,12 @@ static int memcg_alloc_cache_id(void)
int id, size;
int err;

- id = ida_simple_get(&kmem_limited_groups,
+ id = ida_simple_get(&memcg_cache_ida,
0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
if (id < 0)
return id;

- if (id < memcg_limited_groups_array_size)
+ if (id < memcg_max_cache_ids)
return id;

/*
@@ -2950,7 +2949,7 @@ static int memcg_alloc_cache_id(void)
mutex_unlock(&memcg_slab_mutex);

if (err) {
- ida_simple_remove(&kmem_limited_groups, id);
+ ida_simple_remove(&memcg_cache_ida, id);
return err;
}
return id;
@@ -2959,7 +2958,7 @@ static int memcg_alloc_cache_id(void)

static void memcg_free_cache_id(int id)
{
- ida_simple_remove(&kmem_limited_groups, id);
+ ida_simple_remove(&memcg_cache_ida, id);
}

/*
@@ -2969,7 +2968,7 @@ static void memcg_free_cache_id(int id)
*/
void memcg_update_array_size(int num)
{
- memcg_limited_groups_array_size = num;
+ memcg_max_cache_ids = num;
}

static void memcg_register_cache(struct mem_cgroup *memcg,
diff --git a/mm/slab_common.c b/mm/slab_common.c
index d4add958843c..cc6e18437f6c 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -98,7 +98,7 @@ static int memcg_alloc_cache_params(struct mem_cgroup *memcg,

if (!memcg) {
size = offsetof(struct memcg_cache_params, memcg_caches);
- size += memcg_limited_groups_array_size * sizeof(void *);
+ size += memcg_max_cache_ids * sizeof(void *);
} else
size = sizeof(struct memcg_cache_params);

@@ -138,7 +138,7 @@ static int memcg_update_cache_params(struct kmem_cache *s, int num_memcgs)

cur_params = s->memcg_params;
memcpy(new_params->memcg_caches, cur_params->memcg_caches,
- memcg_limited_groups_array_size * sizeof(void *));
+ memcg_max_cache_ids * sizeof(void *));

new_params->is_root_cache = true;
INIT_LIST_HEAD(&new_params->memcg_caches_list);