Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slub: Dont define useless label in the !CONFIG_CMPXCHG_LOCAL case
  slab,rcu: don't assume the size of struct rcu_head
  slub,rcu: don't assume the size of struct rcu_head
  slub: automatically reserve bytes at the end of slab
  Lockless (and preemptless) fastpaths for slub
  slub: Get rid of slab_free_hook_irq()
  slub: min_partial needs to be in first cacheline
  slub: fix ksize() build error
  slub: fix kmemcheck calls to match ksize() hints
  Revert "slab: Fix missing DEBUG_SLAB last user"
  mm: Remove support for kmem_cache_name()

3 files changed, 327 insertions, 100 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 37961d1f584..a18ba57517a 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -191,22 +191,6 @@ typedef unsigned int kmem_bufctl_t;
 #define	SLAB_LIMIT	(((kmem_bufctl_t)(~0U))-3)
 
 /*
- * struct slab
- *
- * Manages the objs in a slab. Placed either at the beginning of mem allocated
- * for a slab, or allocated from an general cache.
- * Slabs are chained into three list: fully used, partial, fully free slabs.
- */
-struct slab {
-	struct list_head list;
-	unsigned long colouroff;
-	void *s_mem;		/* including colour offset */
-	unsigned int inuse;	/* num of objs active in slab */
-	kmem_bufctl_t free;
-	unsigned short nodeid;
-};
-
-/*
  * struct slab_rcu
  *
  * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
@@ -219,8 +203,6 @@ struct slab {
  *
  * rcu_read_lock before reading the address, then rcu_read_unlock after
  * taking the spinlock within the structure expected at that address.
- *
- * We assume struct slab_rcu can overlay struct slab when destroying.
  */
 struct slab_rcu {
 	struct rcu_head head;
@@ -229,6 +211,27 @@ struct slab_rcu {
 };
 
 /*
+ * struct slab
+ *
+ * Manages the objs in a slab. Placed either at the beginning of mem allocated
+ * for a slab, or allocated from an general cache.
+ * Slabs are chained into three list: fully used, partial, fully free slabs.
+ */
+struct slab {
+	union {
+		struct {
+			struct list_head list;
+			unsigned long colouroff;
+			void *s_mem;		/* including colour offset */
+			unsigned int inuse;	/* num of objs active in slab */
+			kmem_bufctl_t free;
+			unsigned short nodeid;
+		};
+		struct slab_rcu __slab_cover_slab_rcu;
+	};
+};
+
+/*
  * struct array_cache
  *
  * Purpose:
@@ -2147,8 +2150,6 @@ static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
  *
  * @name must be valid until the cache is destroyed. This implies that
  * the module calling this has to destroy the cache before getting unloaded.
- * Note that kmem_cache_name() is not guaranteed to return the same pointer,
- * therefore applications must manage it themselves.
  *
  * The flags are
  *
@@ -2288,8 +2289,8 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	if (ralign < align) {
 		ralign = align;
 	}
-	/* disable debug if not aligning with REDZONE_ALIGN */
-	if (ralign & (__alignof__(unsigned long long) - 1))
+	/* disable debug if necessary */
+	if (ralign > __alignof__(unsigned long long))
 		flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
 	/*
 	 * 4) Store it.
@@ -2315,8 +2316,8 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	 */
 	if (flags & SLAB_RED_ZONE) {
 		/* add space for red zone words */
-		cachep->obj_offset += align;
-		size += align + sizeof(unsigned long long);
+		cachep->obj_offset += sizeof(unsigned long long);
+		size += 2 * sizeof(unsigned long long);
 	}
 	if (flags & SLAB_STORE_USER) {
 		/* user store requires one word storage behind the end of
@@ -3840,12 +3841,6 @@ unsigned int kmem_cache_size(struct kmem_cache *cachep)
 }
 EXPORT_SYMBOL(kmem_cache_size);
 
-const char *kmem_cache_name(struct kmem_cache *cachep)
-{
-	return cachep->name;
-}
-EXPORT_SYMBOL_GPL(kmem_cache_name);
-
 /*
  * This initializes kmem_list3 or resizes various caches for all nodes.
  */
diff --git a/mm/slob.c b/mm/slob.c
index 3588eaaef72..46e0aee33a2 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -666,12 +666,6 @@ unsigned int kmem_cache_size(struct kmem_cache *c)
 }
 EXPORT_SYMBOL(kmem_cache_size);
 
-const char *kmem_cache_name(struct kmem_cache *c)
-{
-	return c->name;
-}
-EXPORT_SYMBOL(kmem_cache_name);
-
 int kmem_cache_shrink(struct kmem_cache *d)
 {
 	return 0;
diff --git a/mm/slub.c b/mm/slub.c
index e15aa7f193c..7e4f835e32a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -281,11 +281,40 @@ static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
 	return (p - addr) / s->size;
 }
 
+static inline size_t slab_ksize(const struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_DEBUG
+	/*
+	 * Debugging requires use of the padding between object
+	 * and whatever may come after it.
+	 */
+	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
+		return s->objsize;
+
+#endif
+	/*
+	 * If we have the need to store the freelist pointer
+	 * back there or track user information then we can
+	 * only use the space before that information.
+	 */
+	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
+		return s->inuse;
+	/*
+	 * Else we can use all the padding etc for the allocation
+	 */
+	return s->size;
+}
+
+static inline int order_objects(int order, unsigned long size, int reserved)
+{
+	return ((PAGE_SIZE << order) - reserved) / size;
+}
+
 static inline struct kmem_cache_order_objects oo_make(int order,
-						unsigned long size)
+		unsigned long size, int reserved)
 {
 	struct kmem_cache_order_objects x = {
-		(order << OO_SHIFT) + (PAGE_SIZE << order) / size
+		(order << OO_SHIFT) + order_objects(order, size, reserved)
 	};
 
 	return x;
@@ -617,7 +646,7 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
 		return 1;
 
 	start = page_address(page);
-	length = (PAGE_SIZE << compound_order(page));
+	length = (PAGE_SIZE << compound_order(page)) - s->reserved;
 	end = start + length;
 	remainder = length % s->size;
 	if (!remainder)
@@ -698,7 +727,7 @@ static int check_slab(struct kmem_cache *s, struct page *page)
 		return 0;
 	}
 
-	maxobj = (PAGE_SIZE << compound_order(page)) / s->size;
+	maxobj = order_objects(compound_order(page), s->size, s->reserved);
 	if (page->objects > maxobj) {
 		slab_err(s, page, "objects %u > max %u",
 			s->name, page->objects, maxobj);
@@ -748,7 +777,7 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 		nr++;
 	}
 
-	max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
+	max_objects = order_objects(compound_order(page), s->size, s->reserved);
 	if (max_objects > MAX_OBJS_PER_PAGE)
 		max_objects = MAX_OBJS_PER_PAGE;
 
@@ -800,21 +829,31 @@ static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
 {
 	flags &= gfp_allowed_mask;
-	kmemcheck_slab_alloc(s, flags, object, s->objsize);
+	kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
 	kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
 }
 
 static inline void slab_free_hook(struct kmem_cache *s, void *x)
 {
 	kmemleak_free_recursive(x, s->flags);
-}
 
-static inline void slab_free_hook_irq(struct kmem_cache *s, void *object)
-{
-	kmemcheck_slab_free(s, object, s->objsize);
-	debug_check_no_locks_freed(object, s->objsize);
-	if (!(s->flags & SLAB_DEBUG_OBJECTS))
-		debug_check_no_obj_freed(object, s->objsize);
+	/*
+	 * Trouble is that we may no longer disable interupts in the fast path
+	 * So in order to make the debug calls that expect irqs to be
+	 * disabled we need to disable interrupts temporarily.
+	 */
+#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
+	{
+		unsigned long flags;
+
+		local_irq_save(flags);
+		kmemcheck_slab_free(s, x, s->objsize);
+		debug_check_no_locks_freed(x, s->objsize);
+		if (!(s->flags & SLAB_DEBUG_OBJECTS))
+			debug_check_no_obj_freed(x, s->objsize);
+		local_irq_restore(flags);
+	}
+#endif
 }
 
 /*
@@ -1101,9 +1140,6 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 
 static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
 
-static inline void slab_free_hook_irq(struct kmem_cache *s,
-		void *object) {}
-
 #endif /* CONFIG_SLUB_DEBUG */
 
 /*
@@ -1249,21 +1285,38 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
 	__free_pages(page, order);
 }
 
+#define need_reserve_slab_rcu						\
+	(sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
+
 static void rcu_free_slab(struct rcu_head *h)
 {
 	struct page *page;
 
-	page = container_of((struct list_head *)h, struct page, lru);
+	if (need_reserve_slab_rcu)
+		page = virt_to_head_page(h);
+	else
+		page = container_of((struct list_head *)h, struct page, lru);
+
 	__free_slab(page->slab, page);
 }
 
 static void free_slab(struct kmem_cache *s, struct page *page)
 {
 	if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
-		/*
-		 * RCU free overloads the RCU head over the LRU
-		 */
-		struct rcu_head *head = (void *)&page->lru;
+		struct rcu_head *head;
+
+		if (need_reserve_slab_rcu) {
+			int order = compound_order(page);
+			int offset = (PAGE_SIZE << order) - s->reserved;
+
+			VM_BUG_ON(s->reserved != sizeof(*head));
+			head = page_address(page) + offset;
+		} else {
+			/*
+			 * RCU free overloads the RCU head over the LRU
+			 */
+			head = (void *)&page->lru;
+		}
 
 		call_rcu(head, rcu_free_slab);
 	} else
@@ -1487,6 +1540,77 @@ static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
 	}
 }
 
+#ifdef CONFIG_CMPXCHG_LOCAL
+#ifdef CONFIG_PREEMPT
+/*
+ * Calculate the next globally unique transaction for disambiguiation
+ * during cmpxchg. The transactions start with the cpu number and are then
+ * incremented by CONFIG_NR_CPUS.
+ */
+#define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
+#else
+/*
+ * No preemption supported therefore also no need to check for
+ * different cpus.
+ */
+#define TID_STEP 1
+#endif
+
+static inline unsigned long next_tid(unsigned long tid)
+{
+	return tid + TID_STEP;
+}
+
+static inline unsigned int tid_to_cpu(unsigned long tid)
+{
+	return tid % TID_STEP;
+}
+
+static inline unsigned long tid_to_event(unsigned long tid)
+{
+	return tid / TID_STEP;
+}
+
+static inline unsigned int init_tid(int cpu)
+{
+	return cpu;
+}
+
+static inline void note_cmpxchg_failure(const char *n,
+		const struct kmem_cache *s, unsigned long tid)
+{
+#ifdef SLUB_DEBUG_CMPXCHG
+	unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
+
+	printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
+
+#ifdef CONFIG_PREEMPT
+	if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
+		printk("due to cpu change %d -> %d\n",
+			tid_to_cpu(tid), tid_to_cpu(actual_tid));
+	else
+#endif
+	if (tid_to_event(tid) != tid_to_event(actual_tid))
+		printk("due to cpu running other code. Event %ld->%ld\n",
+			tid_to_event(tid), tid_to_event(actual_tid));
+	else
+		printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
+			actual_tid, tid, next_tid(tid));
+#endif
+}
+
+#endif
+
+void init_kmem_cache_cpus(struct kmem_cache *s)
+{
+#if defined(CONFIG_CMPXCHG_LOCAL) && defined(CONFIG_PREEMPT)
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
+#endif
+
+}
 /*
  * Remove the cpu slab
  */
@@ -1518,6 +1642,9 @@ static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 		page->inuse--;
 	}
 	c->page = NULL;
+#ifdef CONFIG_CMPXCHG_LOCAL
+	c->tid = next_tid(c->tid);
+#endif
 	unfreeze_slab(s, page, tail);
 }
 
@@ -1652,6 +1779,19 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 {
 	void **object;
 	struct page *new;
+#ifdef CONFIG_CMPXCHG_LOCAL
+	unsigned long flags;
+
+	local_irq_save(flags);
+#ifdef CONFIG_PREEMPT
+	/*
+	 * We may have been preempted and rescheduled on a different
+	 * cpu before disabling interrupts. Need to reload cpu area
+	 * pointer.
+	 */
+	c = this_cpu_ptr(s->cpu_slab);
+#endif
+#endif
 
 	/* We handle __GFP_ZERO in the caller */
 	gfpflags &= ~__GFP_ZERO;
@@ -1678,6 +1818,10 @@ load_freelist:
 	c->node = page_to_nid(c->page);
 unlock_out:
 	slab_unlock(c->page);
+#ifdef CONFIG_CMPXCHG_LOCAL
+	c->tid = next_tid(c->tid);
+	local_irq_restore(flags);
+#endif
 	stat(s, ALLOC_SLOWPATH);
 	return object;
 
@@ -1739,23 +1883,76 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
 {
 	void **object;
 	struct kmem_cache_cpu *c;
+#ifdef CONFIG_CMPXCHG_LOCAL
+	unsigned long tid;
+#else
 	unsigned long flags;
+#endif
 
 	if (slab_pre_alloc_hook(s, gfpflags))
 		return NULL;
 
+#ifndef CONFIG_CMPXCHG_LOCAL
 	local_irq_save(flags);
+#else
+redo:
+#endif
+
+	/*
+	 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
+	 * enabled. We may switch back and forth between cpus while
+	 * reading from one cpu area. That does not matter as long
+	 * as we end up on the original cpu again when doing the cmpxchg.
+	 */
 	c = __this_cpu_ptr(s->cpu_slab);
+
+#ifdef CONFIG_CMPXCHG_LOCAL
+	/*
+	 * The transaction ids are globally unique per cpu and per operation on
+	 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
+	 * occurs on the right processor and that there was no operation on the
+	 * linked list in between.
+	 */
+	tid = c->tid;
+	barrier();
+#endif
+
 	object = c->freelist;
 	if (unlikely(!object || !node_match(c, node)))
 
 		object = __slab_alloc(s, gfpflags, node, addr, c);
 
 	else {
+#ifdef CONFIG_CMPXCHG_LOCAL
+		/*
+		 * The cmpxchg will only match if there was no additonal
+		 * operation and if we are on the right processor.
+		 *
+		 * The cmpxchg does the following atomically (without lock semantics!)
+		 * 1. Relocate first pointer to the current per cpu area.
+		 * 2. Verify that tid and freelist have not been changed
+		 * 3. If they were not changed replace tid and freelist
+		 *
+		 * Since this is without lock semantics the protection is only against
+		 * code executing on this cpu *not* from access by other cpus.
+		 */
+		if (unlikely(!this_cpu_cmpxchg_double(
+				s->cpu_slab->freelist, s->cpu_slab->tid,
+				object, tid,
+				get_freepointer(s, object), next_tid(tid)))) {
+
+			note_cmpxchg_failure("slab_alloc", s, tid);
+			goto redo;
+		}
+#else
 		c->freelist = get_freepointer(s, object);
+#endif
 		stat(s, ALLOC_FASTPATH);
 	}
+
+#ifndef CONFIG_CMPXCHG_LOCAL
 	local_irq_restore(flags);
+#endif
 
 	if (unlikely(gfpflags & __GFP_ZERO) && object)
 		memset(object, 0, s->objsize);
@@ -1833,9 +2030,13 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 {
 	void *prior;
 	void **object = (void *)x;
+#ifdef CONFIG_CMPXCHG_LOCAL
+	unsigned long flags;
 
-	stat(s, FREE_SLOWPATH);
+	local_irq_save(flags);
+#endif
 	slab_lock(page);
+	stat(s, FREE_SLOWPATH);
 
 	if (kmem_cache_debug(s))
 		goto debug;
@@ -1865,6 +2066,9 @@ checks_ok:
 
 out_unlock:
 	slab_unlock(page);
+#ifdef CONFIG_CMPXCHG_LOCAL
+	local_irq_restore(flags);
+#endif
 	return;
 
 slab_empty:
@@ -1876,6 +2080,9 @@ slab_empty:
 		stat(s, FREE_REMOVE_PARTIAL);
 	}
 	slab_unlock(page);
+#ifdef CONFIG_CMPXCHG_LOCAL
+	local_irq_restore(flags);
+#endif
 	stat(s, FREE_SLAB);
 	discard_slab(s, page);
 	return;
@@ -1902,23 +2109,56 @@ static __always_inline void slab_free(struct kmem_cache *s,
 {
 	void **object = (void *)x;
 	struct kmem_cache_cpu *c;
+#ifdef CONFIG_CMPXCHG_LOCAL
+	unsigned long tid;
+#else
 	unsigned long flags;
+#endif
 
 	slab_free_hook(s, x);
 
+#ifndef CONFIG_CMPXCHG_LOCAL
 	local_irq_save(flags);
+
+#else
+redo:
+#endif
+
+	/*
+	 * Determine the currently cpus per cpu slab.
+	 * The cpu may change afterward. However that does not matter since
+	 * data is retrieved via this pointer. If we are on the same cpu
+	 * during the cmpxchg then the free will succedd.
+	 */
 	c = __this_cpu_ptr(s->cpu_slab);
 
-	slab_free_hook_irq(s, x);
+#ifdef CONFIG_CMPXCHG_LOCAL
+	tid = c->tid;
+	barrier();
+#endif
 
 	if (likely(page == c->page && c->node != NUMA_NO_NODE)) {
 		set_freepointer(s, object, c->freelist);
+
+#ifdef CONFIG_CMPXCHG_LOCAL
+		if (unlikely(!this_cpu_cmpxchg_double(
+				s->cpu_slab->freelist, s->cpu_slab->tid,
+				c->freelist, tid,
+				object, next_tid(tid)))) {
+
+			note_cmpxchg_failure("slab_free", s, tid);
+			goto redo;
+		}
+#else
 		c->freelist = object;
+#endif
 		stat(s, FREE_FASTPATH);
 	} else
 		__slab_free(s, page, x, addr);
 
+#ifndef CONFIG_CMPXCHG_LOCAL
 	local_irq_restore(flags);
+#endif
 }
 
 void kmem_cache_free(struct kmem_cache *s, void *x)
@@ -1988,13 +2228,13 @@ static int slub_nomerge;
  * the smallest order which will fit the object.
  */
 static inline int slab_order(int size, int min_objects,
-				int max_order, int fract_leftover)
+				int max_order, int fract_leftover, int reserved)
 {
 	int order;
 	int rem;
 	int min_order = slub_min_order;
 
-	if ((PAGE_SIZE << min_order) / size > MAX_OBJS_PER_PAGE)
+	if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
 		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
 
 	for (order = max(min_order,
@@ -2003,10 +2243,10 @@ static inline int slab_order(int size, int min_objects,
 
 		unsigned long slab_size = PAGE_SIZE << order;
 
-		if (slab_size < min_objects * size)
+		if (slab_size < min_objects * size + reserved)
 			continue;
 
-		rem = slab_size % size;
+		rem = (slab_size - reserved) % size;
 
 		if (rem <= slab_size / fract_leftover)
 			break;
@@ -2016,7 +2256,7 @@ static inline int slab_order(int size, int min_objects,
 	return order;
 }
 
-static inline int calculate_order(int size)
+static inline int calculate_order(int size, int reserved)
 {
 	int order;
 	int min_objects;
@@ -2034,14 +2274,14 @@ static inline int calculate_order(int size)
 	min_objects = slub_min_objects;
 	if (!min_objects)
 		min_objects = 4 * (fls(nr_cpu_ids) + 1);
-	max_objects = (PAGE_SIZE << slub_max_order)/size;
+	max_objects = order_objects(slub_max_order, size, reserved);
 	min_objects = min(min_objects, max_objects);
 
 	while (min_objects > 1) {
 		fraction = 16;
 		while (fraction >= 4) {
 			order = slab_order(size, min_objects,
-						slub_max_order, fraction);
+					slub_max_order, fraction, reserved);
 			if (order <= slub_max_order)
 				return order;
 			fraction /= 2;
@@ -2053,14 +2293,14 @@ static inline int calculate_order(int size)
 	 * We were unable to place multiple objects in a slab. Now
 	 * lets see if we can place a single object there.
 	 */
-	order = slab_order(size, 1, slub_max_order, 1);
+	order = slab_order(size, 1, slub_max_order, 1, reserved);
 	if (order <= slub_max_order)
 		return order;
 
 	/*
 	 * Doh this slab cannot be placed using slub_max_order.
 	 */
-	order = slab_order(size, 1, MAX_ORDER, 1);
+	order = slab_order(size, 1, MAX_ORDER, 1, reserved);
 	if (order < MAX_ORDER)
 		return order;
 	return -ENOSYS;
@@ -2110,9 +2350,23 @@ static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
 	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
 			SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
 
+#ifdef CONFIG_CMPXCHG_LOCAL
+	/*
+	 * Must align to double word boundary for the double cmpxchg instructions
+	 * to work.
+	 */
+	s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu), 2 * sizeof(void *));
+#else
+	/* Regular alignment is sufficient */
 	s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);
+#endif
 
-	return s->cpu_slab != NULL;
+	if (!s->cpu_slab)
+		return 0;
+
+	init_kmem_cache_cpus(s);
+
+	return 1;
 }
 
 static struct kmem_cache *kmem_cache_node;
@@ -2311,7 +2565,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
 	if (forced_order >= 0)
 		order = forced_order;
 	else
-		order = calculate_order(size);
+		order = calculate_order(size, s->reserved);
 
 	if (order < 0)
 		return 0;
@@ -2329,8 +2583,8 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
 	/*
 	 * Determine the number of objects per slab
 	 */
-	s->oo = oo_make(order, size);
-	s->min = oo_make(get_order(size), size);
+	s->oo = oo_make(order, size, s->reserved);
+	s->min = oo_make(get_order(size), size, s->reserved);
 	if (oo_objects(s->oo) > oo_objects(s->max))
 		s->max = s->oo;
 
@@ -2349,6 +2603,10 @@ static int kmem_cache_open(struct kmem_cache *s,
 	s->objsize = size;
 	s->align = align;
 	s->flags = kmem_cache_flags(size, flags, name, ctor);
+	s->reserved = 0;
+
+	if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
+		s->reserved = sizeof(struct rcu_head);
 
 	if (!calculate_sizes(s, -1))
 		goto error;
@@ -2399,12 +2657,6 @@ unsigned int kmem_cache_size(struct kmem_cache *s)
 }
 EXPORT_SYMBOL(kmem_cache_size);
 
-const char *kmem_cache_name(struct kmem_cache *s)
-{
-	return s->name;
-}
-EXPORT_SYMBOL(kmem_cache_name);
-
 static void list_slab_objects(struct kmem_cache *s, struct page *page,
 							const char *text)
 {
@@ -2696,7 +2948,6 @@ EXPORT_SYMBOL(__kmalloc_node);
 size_t ksize(const void *object)
 {
 	struct page *page;
-	struct kmem_cache *s;
 
 	if (unlikely(object == ZERO_SIZE_PTR))
 		return 0;
@@ -2707,28 +2958,8 @@ size_t ksize(const void *object)
 		WARN_ON(!PageCompound(page));
 		return PAGE_SIZE << compound_order(page);
 	}
-	s = page->slab;
 
-#ifdef CONFIG_SLUB_DEBUG
-	/*
-	 * Debugging requires use of the padding between object
-	 * and whatever may come after it.
-	 */
-	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
-		return s->objsize;
-
-#endif
-	/*
-	 * If we have the need to store the freelist pointer
-	 * back there or track user information then we can
-	 * only use the space before that information.
-	 */
-	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
-		return s->inuse;
-	/*
-	 * Else we can use all the padding etc for the allocation
-	 */
-	return s->size;
+	return slab_ksize(page->slab);
 }
 EXPORT_SYMBOL(ksize);
 
@@ -4017,6 +4248,12 @@ static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
 }
 SLAB_ATTR_RO(destroy_by_rcu);
 
+static ssize_t reserved_show(struct kmem_cache *s, char *buf)
+{
+	return sprintf(buf, "%d\n", s->reserved);
+}
+SLAB_ATTR_RO(reserved);
+
 #ifdef CONFIG_SLUB_DEBUG
 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
 {
@@ -4303,6 +4540,7 @@ static struct attribute *slab_attrs[] = {
 	&reclaim_account_attr.attr,
 	&destroy_by_rcu_attr.attr,
 	&shrink_attr.attr,
+	&reserved_attr.attr,
 #ifdef CONFIG_SLUB_DEBUG
 	&total_objects_attr.attr,
 	&slabs_attr.attr,