slab: reorganize memcg_cache_params
We're going to change how memcg caches are iterated. In preparation,
clean up and reorganize memcg_cache_params.
* The shared ->list is replaced by ->children in root and
->children_node in children.
* ->is_root_cache is removed. Instead ->root_cache is moved out of
the child union and now used by both root and children. NULL
indicates root cache. Non-NULL a memcg one.
This patch doesn't cause any observable behavior changes.
Link: http://lkml.kernel.org/r/20170117235411.9408-5-tj@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/slab_common.c b/mm/slab_common.c
index ac469c8..c388503 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -140,9 +140,9 @@
#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
void slab_init_memcg_params(struct kmem_cache *s)
{
- s->memcg_params.is_root_cache = true;
- INIT_LIST_HEAD(&s->memcg_params.list);
+ s->memcg_params.root_cache = NULL;
RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
+ INIT_LIST_HEAD(&s->memcg_params.children);
}
static int init_memcg_params(struct kmem_cache *s,
@@ -150,10 +150,10 @@
{
struct memcg_cache_array *arr;
- if (memcg) {
- s->memcg_params.is_root_cache = false;
- s->memcg_params.memcg = memcg;
+ if (root_cache) {
s->memcg_params.root_cache = root_cache;
+ s->memcg_params.memcg = memcg;
+ INIT_LIST_HEAD(&s->memcg_params.children_node);
return 0;
}
@@ -223,7 +223,7 @@
static void unlink_memcg_cache(struct kmem_cache *s)
{
- list_del(&s->memcg_params.list);
+ list_del(&s->memcg_params.children_node);
}
#else
static inline int init_memcg_params(struct kmem_cache *s,
@@ -594,7 +594,8 @@
goto out_unlock;
}
- list_add(&s->memcg_params.list, &root_cache->memcg_params.list);
+ list_add(&s->memcg_params.children_node,
+ &root_cache->memcg_params.children);
/*
* Since readers won't lock (see cache_from_memcg_idx()), we need a
@@ -690,7 +691,7 @@
* list so as not to try to destroy it for a second
* time while iterating over inactive caches below.
*/
- list_move(&c->memcg_params.list, &busy);
+ list_move(&c->memcg_params.children_node, &busy);
else
/*
* The cache is empty and will be destroyed soon. Clear
@@ -705,17 +706,17 @@
* Second, shutdown all caches left from memory cgroups that are now
* offline.
*/
- list_for_each_entry_safe(c, c2, &s->memcg_params.list,
- memcg_params.list)
+ list_for_each_entry_safe(c, c2, &s->memcg_params.children,
+ memcg_params.children_node)
shutdown_cache(c);
- list_splice(&busy, &s->memcg_params.list);
+ list_splice(&busy, &s->memcg_params.children);
/*
* A cache being destroyed must be empty. In particular, this means
* that all per memcg caches attached to it must be empty too.
*/
- if (!list_empty(&s->memcg_params.list))
+ if (!list_empty(&s->memcg_params.children))
return -EBUSY;
return 0;
}