mm: memcg/slab: remove memcg_kmem_get_cache()

The memcg_kmem_get_cache() function became really trivial, so let's just
inline it into the single call point: memcg_slab_pre_alloc_hook().

It will make the code less bulky and can also help the compiler to
generate a better code.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-15-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 2ac84dcfc9e5a334aae24af9356748661112f822..5a8b62d075e60f980af589195b5b32f18579356a 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1403,8 +1403,6 @@ static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
 }
 #endif
 
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
-
 #ifdef CONFIG_MEMCG_KMEM
 int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
                        unsigned int nr_pages);

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c713867e496d3c39d895690cbd0bc4ffd90e7b78..a8113b77b23a1f634f051f94c6e0039a74d921c0 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -393,7 +393,7 @@ void memcg_put_cache_ids(void)
 
 /*
  * A lot of the calls to the cache allocation functions are expected to be
- * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
+ * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
  * conditional to this static branch, we'll have to allow modules that does
  * kmem_cache_alloc and the such to see this symbol as well
  */
@@ -2900,29 +2900,6 @@ static void memcg_free_cache_id(int id)
        ida_simple_remove(&memcg_cache_ida, id);
 }
 
-/**
- * memcg_kmem_get_cache: select memcg or root cache for allocation
- * @cachep: the original global kmem cache
- *
- * Return the kmem_cache we're supposed to use for a slab allocation.
- *
- * If the cache does not exist yet, if we are the first user of it, we
- * create it asynchronously in a workqueue and let the current allocation
- * go through with the original cache.
- */
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
-{
-       struct kmem_cache *memcg_cachep;
-
-       memcg_cachep = READ_ONCE(cachep->memcg_params.memcg_cache);
-       if (unlikely(!memcg_cachep)) {
-               queue_work(system_wq, &cachep->memcg_params.work);
-               return cachep;
-       }
-
-       return memcg_cachep;
-}
-
 /**
  * __memcg_kmem_charge: charge a number of kernel pages to a memcg
  * @memcg: memory cgroup to charge

diff --git a/mm/slab.h b/mm/slab.h
index fd9fcdfb37899eab81275fec38f677fa1f0f602e..342eac8529677d4d836392ba75f06bd7f18a7439 100644 (file)
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -365,9 +365,16 @@ static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
        if (memcg_kmem_bypass())
                return s;
 
-       cachep = memcg_kmem_get_cache(s);
-       if (is_root_cache(cachep))
+       cachep = READ_ONCE(s->memcg_params.memcg_cache);
+       if (unlikely(!cachep)) {
+               /*
+                * If memcg cache does not exist yet, we schedule it's
+                * asynchronous creation and let the current allocation
+                * go through with the root cache.
+                */
+               queue_work(system_wq, &s->memcg_params.work);
                return s;
+       }
 
        objcg = get_obj_cgroup_from_current();
        if (!objcg)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index b898698f6c8ac0f04bf4556ac953598770891cea..de0a46cf974a7ebe3580103ac9887d52e59f2fd0 100644 (file)
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -570,7 +570,7 @@ void memcg_create_kmem_cache(struct kmem_cache *root_cache)
        }
 
        /*
-        * Since readers won't lock (see memcg_kmem_get_cache()), we need a
+        * Since readers won't lock (see memcg_slab_pre_alloc_hook()), we need a
         * barrier here to ensure nobody will see the kmem_cache partially
         * initialized.
         */