3 files changed, 42 insertions, 13 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index b00c1c73eb0a..79d59c937fac 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -45,9 +45,9 @@ struct kmem_cache_cpu {
 struct kmem_cache_node {
         spinlock_t list_lock;   /* Protect partial list and nr_partial */
         unsigned long nr_partial;
-        atomic_long_t nr_slabs;
         struct list_head partial;
 #ifdef CONFIG_SLUB_DEBUG
+        atomic_long_t nr_slabs;
         struct list_head full;
 #endif
 };
diff --git a/init/Kconfig b/init/Kconfig
index a97924bc5b8d..7fccf09bb95a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -763,7 +763,7 @@ endmenu		# General setup
 config SLABINFO
         bool
         depends on PROC_FS
-        depends on SLAB || SLUB
+        depends on SLAB || SLUB_DEBUG
         default y
 
 config RT_MUTEXES
diff --git a/mm/slub.c b/mm/slub.c
index f924cffb29e7..7f8aaa291a4e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -837,6 +837,35 @@ static void remove_full(struct kmem_cache *s, struct page *page)
         spin_unlock(&n->list_lock);
 }
 
+/* Tracking of the number of slabs for debugging purposes */
+static inline unsigned long slabs_node(struct kmem_cache *s, int node)
+{
+        struct kmem_cache_node *n = get_node(s, node);
+
+        return atomic_long_read(&n->nr_slabs);
+}
+
+static inline void inc_slabs_node(struct kmem_cache *s, int node)
+{
+        struct kmem_cache_node *n = get_node(s, node);
+
+        /*
+         * May be called early in order to allocate a slab for the
+         * kmem_cache_node structure. Solve the chicken-egg
+         * dilemma by deferring the increment of the count during
+         * bootstrap (see early_kmem_cache_node_alloc).
+         */
+        if (!NUMA_BUILD || n)
+                atomic_long_inc(&n->nr_slabs);
+}
+static inline void dec_slabs_node(struct kmem_cache *s, int node)
+{
+        struct kmem_cache_node *n = get_node(s, node);
+
+        atomic_long_dec(&n->nr_slabs);
+}
+
+/* Object debug checks for alloc/free paths */
 static void setup_object_debug(struct kmem_cache *s, struct page *page,
                                                                 void *object)
 {
@@ -1028,6 +1057,11 @@ static inline unsigned long kmem_cache_flags(unsigned long objsize,
         return flags;
 }
 #define slub_debug 0
+
+static inline unsigned long slabs_node(struct kmem_cache *s, int node)
+                                                        { return 0; }
+static inline void inc_slabs_node(struct kmem_cache *s, int node) {}
+static inline void dec_slabs_node(struct kmem_cache *s, int node) {}
 #endif
 /*
  * Slab allocation and freeing
@@ -1066,7 +1100,6 @@ static void setup_object(struct kmem_cache *s, struct page *page,
 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
         struct page *page;
-        struct kmem_cache_node *n;
         void *start;
         void *last;
         void *p;
@@ -1078,9 +1111,7 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
         if (!page)
                 goto out;
 
-        n = get_node(s, page_to_nid(page));
-        if (n)
-                atomic_long_inc(&n->nr_slabs);
+        inc_slabs_node(s, page_to_nid(page));
         page->slab = s;
         page->flags |= 1 << PG_slab;
         if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
@@ -1153,9 +1184,7 @@ static void free_slab(struct kmem_cache *s, struct page *page)
 
 static void discard_slab(struct kmem_cache *s, struct page *page)
 {
-        struct kmem_cache_node *n = get_node(s, page_to_nid(page));
-
-        atomic_long_dec(&n->nr_slabs);
+        dec_slabs_node(s, page_to_nid(page));
         free_slab(s, page);
 }
 
@@ -1894,10 +1923,10 @@ static void init_kmem_cache_cpu(struct kmem_cache *s,
 static void init_kmem_cache_node(struct kmem_cache_node *n)
 {
         n->nr_partial = 0;
-        atomic_long_set(&n->nr_slabs, 0);
         spin_lock_init(&n->list_lock);
         INIT_LIST_HEAD(&n->partial);
 #ifdef CONFIG_SLUB_DEBUG
+        atomic_long_set(&n->nr_slabs, 0);
         INIT_LIST_HEAD(&n->full);
 #endif
 }
@@ -2066,7 +2095,7 @@ static struct kmem_cache_node *early_kmem_cache_node_alloc(gfp_t gfpflags,
         init_tracking(kmalloc_caches, n);
 #endif
         init_kmem_cache_node(n);
-        atomic_long_inc(&n->nr_slabs);
+        inc_slabs_node(kmalloc_caches, node);
 
         /*
          * lockdep requires consistent irq usage for each lock
@@ -2379,7 +2408,7 @@ static inline int kmem_cache_close(struct kmem_cache *s)
                 struct kmem_cache_node *n = get_node(s, node);
 
                 n->nr_partial -= free_list(s, n, &n->partial);
-                if (atomic_long_read(&n->nr_slabs))
+                if (slabs_node(s, node))
                         return 1;
         }
         free_kmem_cache_nodes(s);
@@ -2801,7 +2830,7 @@ static void slab_mem_offline_callback(void *arg)
                          * and offline_pages() function shoudn't call this
                          * callback. So, we must fail.
                          */
-                        BUG_ON(atomic_long_read(&n->nr_slabs));
+                        BUG_ON(slabs_node(s, offline_node));
 
                         s->node[offline_node] = NULL;
                         kmem_cache_free(kmalloc_caches, n);