1 files changed, 174 insertions, 4 deletions

diff --git a/mm/slab_common.c b/mm/slab_common.c
index d319502b2403..3a6e0cfdf03a 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -30,6 +30,43 @@ LIST_HEAD(slab_caches);
 DEFINE_MUTEX(slab_mutex);
 struct kmem_cache *kmem_cache;
 
+/*
+ * Set of flags that will prevent slab merging
+ */
+#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
+		SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
+		SLAB_FAILSLAB)
+
+#define SLAB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
+		SLAB_CACHE_DMA | SLAB_NOTRACK)
+
+/*
+ * Merge control. If this is set then no merging of slab caches will occur.
+ * (Could be removed. This was introduced to pacify the merge skeptics.)
+ */
+static int slab_nomerge;
+
+static int __init setup_slab_nomerge(char *str)
+{
+	slab_nomerge = 1;
+	return 1;
+}
+
+#ifdef CONFIG_SLUB
+__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
+#endif
+
+__setup("slab_nomerge", setup_slab_nomerge);
+
+/*
+ * Determine the size of a slab object
+ */
+unsigned int kmem_cache_size(struct kmem_cache *s)
+{
+	return s->object_size;
+}
+EXPORT_SYMBOL(kmem_cache_size);
+
 #ifdef CONFIG_DEBUG_VM
 static int kmem_cache_sanity_check(const char *name, size_t size)
 {
@@ -79,6 +116,65 @@ static inline int kmem_cache_sanity_check(const char *name, size_t size)
 #endif
 
 #ifdef CONFIG_MEMCG_KMEM
+static int memcg_alloc_cache_params(struct mem_cgroup *memcg,
+		struct kmem_cache *s, struct kmem_cache *root_cache)
+{
+	size_t size;
+
+	if (!memcg_kmem_enabled())
+		return 0;
+
+	if (!memcg) {
+		size = offsetof(struct memcg_cache_params, memcg_caches);
+		size += memcg_limited_groups_array_size * sizeof(void *);
+	} else
+		size = sizeof(struct memcg_cache_params);
+
+	s->memcg_params = kzalloc(size, GFP_KERNEL);
+	if (!s->memcg_params)
+		return -ENOMEM;
+
+	if (memcg) {
+		s->memcg_params->memcg = memcg;
+		s->memcg_params->root_cache = root_cache;
+	} else
+		s->memcg_params->is_root_cache = true;
+
+	return 0;
+}
+
+static void memcg_free_cache_params(struct kmem_cache *s)
+{
+	kfree(s->memcg_params);
+}
+
+static int memcg_update_cache_params(struct kmem_cache *s, int num_memcgs)
+{
+	int size;
+	struct memcg_cache_params *new_params, *cur_params;
+
+	BUG_ON(!is_root_cache(s));
+
+	size = offsetof(struct memcg_cache_params, memcg_caches);
+	size += num_memcgs * sizeof(void *);
+
+	new_params = kzalloc(size, GFP_KERNEL);
+	if (!new_params)
+		return -ENOMEM;
+
+	cur_params = s->memcg_params;
+	memcpy(new_params->memcg_caches, cur_params->memcg_caches,
+	       memcg_limited_groups_array_size * sizeof(void *));
+
+	new_params->is_root_cache = true;
+
+	rcu_assign_pointer(s->memcg_params, new_params);
+	if (cur_params)
+		kfree_rcu(cur_params, rcu_head);
+
+	return 0;
+}
+
 int memcg_update_all_caches(int num_memcgs)
 {
 	struct kmem_cache *s;
@@ -89,9 +185,8 @@ int memcg_update_all_caches(int num_memcgs)
 		if (!is_root_cache(s))
 			continue;
 
-		ret = memcg_update_cache_size(s, num_memcgs);
+		ret = memcg_update_cache_params(s, num_memcgs);
 		/*
-		 * See comment in memcontrol.c, memcg_update_cache_size:
 		 * Instead of freeing the memory, we'll just leave the caches
 		 * up to this point in an updated state.
 		 */
@@ -104,7 +199,80 @@ out:
 	mutex_unlock(&slab_mutex);
 	return ret;
 }
-#endif
+#else
+static inline int memcg_alloc_cache_params(struct mem_cgroup *memcg,
+		struct kmem_cache *s, struct kmem_cache *root_cache)
+{
+	return 0;
+}
+
+static inline void memcg_free_cache_params(struct kmem_cache *s)
+{
+}
+#endif /* CONFIG_MEMCG_KMEM */
+
+/*
+ * Find a mergeable slab cache
+ */
+int slab_unmergeable(struct kmem_cache *s)
+{
+	if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
+		return 1;
+
+	if (!is_root_cache(s))
+		return 1;
+
+	if (s->ctor)
+		return 1;
+
+	/*
+	 * We may have set a slab to be unmergeable during bootstrap.
+	 */
+	if (s->refcount < 0)
+		return 1;
+
+	return 0;
+}
+
+struct kmem_cache *find_mergeable(size_t size, size_t align,
+		unsigned long flags, const char *name, void (*ctor)(void *))
+{
+	struct kmem_cache *s;
+
+	if (slab_nomerge || (flags & SLAB_NEVER_MERGE))
+		return NULL;
+
+	if (ctor)
+		return NULL;
+
+	size = ALIGN(size, sizeof(void *));
+	align = calculate_alignment(flags, align, size);
+	size = ALIGN(size, align);
+	flags = kmem_cache_flags(size, flags, name, NULL);
+
+	list_for_each_entry(s, &slab_caches, list) {
+		if (slab_unmergeable(s))
+			continue;
+
+		if (size > s->size)
+			continue;
+
+		if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
+			continue;
+		/*
+		 * Check if alignment is compatible.
+		 * Courtesy of Adrian Drzewiecki
+		 */
+		if ((s->size & ~(align - 1)) != s->size)
+			continue;
+
+		if (s->size - size >= sizeof(void *))
+			continue;
+
+		return s;
+	}
+	return NULL;
+}
 
 /*
  * Figure out what the alignment of the objects will be given a set of
@@ -211,8 +379,10 @@ kmem_cache_create(const char *name, size_t size, size_t align,
 	mutex_lock(&slab_mutex);
 
 	err = kmem_cache_sanity_check(name, size);
-	if (err)
+	if (err) {
+		s = NULL;	/* suppress uninit var warning */
 		goto out_unlock;
+	}
 
 	/*
 	 * Some allocators will constraint the set of valid flags to a subset