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

* 'slub/lockless' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: (21 commits)
  slub: When allocating a new slab also prep the first object
  slub: disable interrupts in cmpxchg_double_slab when falling back to pagelock
  Avoid duplicate _count variables in page_struct
  Revert "SLUB: Fix build breakage in linux/mm_types.h"
  SLUB: Fix build breakage in linux/mm_types.h
  slub: slabinfo update for cmpxchg handling
  slub: Not necessary to check for empty slab on load_freelist
  slub: fast release on full slab
  slub: Add statistics for the case that the current slab does not match the node
  slub: Get rid of the another_slab label
  slub: Avoid disabling interrupts in free slowpath
  slub: Disable interrupts in free_debug processing
  slub: Invert locking and avoid slab lock
  slub: Rework allocator fastpaths
  slub: Pass kmem_cache struct to lock and freeze slab
  slub: explicit list_lock taking
  slub: Add cmpxchg_double_slab()
  mm: Rearrange struct page
  slub: Move page->frozen handling near where the page->freelist handling occurs
  slub: Do not use frozen page flag but a bit in the page counters
  ...

1 files changed, 512 insertions, 252 deletions

diff --git a/mm/slub.c b/mm/slub.c
index f8f5e8efeb88..eb5a8f93338a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2,10 +2,11 @@
  * SLUB: A slab allocator that limits cache line use instead of queuing
  * objects in per cpu and per node lists.
  *
- * The allocator synchronizes using per slab locks and only
- * uses a centralized lock to manage a pool of partial slabs.
+ * The allocator synchronizes using per slab locks or atomic operatios
+ * and only uses a centralized lock to manage a pool of partial slabs.
  *
  * (C) 2007 SGI, Christoph Lameter
+ * (C) 2011 Linux Foundation, Christoph Lameter
  */
 
 #include <linux/mm.h>
@@ -33,15 +34,27 @@
 
 /*
  * Lock order:
- *   1. slab_lock(page)
- *   2. slab->list_lock
+ *   1. slub_lock (Global Semaphore)
+ *   2. node->list_lock
+ *   3. slab_lock(page) (Only on some arches and for debugging)
  *
- *   The slab_lock protects operations on the object of a particular
- *   slab and its metadata in the page struct. If the slab lock
- *   has been taken then no allocations nor frees can be performed
- *   on the objects in the slab nor can the slab be added or removed
- *   from the partial or full lists since this would mean modifying
- *   the page_struct of the slab.
+ *   slub_lock
+ *
+ *   The role of the slub_lock is to protect the list of all the slabs
+ *   and to synchronize major metadata changes to slab cache structures.
+ *
+ *   The slab_lock is only used for debugging and on arches that do not
+ *   have the ability to do a cmpxchg_double. It only protects the second
+ *   double word in the page struct. Meaning
+ *      A. page->freelist       -> List of object free in a page
+ *      B. page->counters       -> Counters of objects
+ *      C. page->frozen         -> frozen state
+ *
+ *   If a slab is frozen then it is exempt from list management. It is not
+ *   on any list. The processor that froze the slab is the one who can
+ *   perform list operations on the page. Other processors may put objects
+ *   onto the freelist but the processor that froze the slab is the only
+ *   one that can retrieve the objects from the page's freelist.
  *
  *   The list_lock protects the partial and full list on each node and
  *   the partial slab counter. If taken then no new slabs may be added or
@@ -54,20 +67,6 @@
  *   slabs, operations can continue without any centralized lock. F.e.
  *   allocating a long series of objects that fill up slabs does not require
  *   the list lock.
- *
- *   The lock order is sometimes inverted when we are trying to get a slab
- *   off a list. We take the list_lock and then look for a page on the list
- *   to use. While we do that objects in the slabs may be freed. We can
- *   only operate on the slab if we have also taken the slab_lock. So we use
- *   a slab_trylock() on the slab. If trylock was successful then no frees
- *   can occur anymore and we can use the slab for allocations etc. If the
- *   slab_trylock() does not succeed then frees are in progress in the slab and
- *   we must stay away from it for a while since we may cause a bouncing
- *   cacheline if we try to acquire the lock. So go onto the next slab.
- *   If all pages are busy then we may allocate a new slab instead of reusing
- *   a partial slab. A new slab has no one operating on it and thus there is
- *   no danger of cacheline contention.
- *
  *   Interrupts are disabled during allocation and deallocation in order to
  *   make the slab allocator safe to use in the context of an irq. In addition
  *   interrupts are disabled to ensure that the processor does not change
@@ -132,6 +131,9 @@ static inline int kmem_cache_debug(struct kmem_cache *s)
 /* Enable to test recovery from slab corruption on boot */
 #undef SLUB_RESILIENCY_TEST
 
+/* Enable to log cmpxchg failures */
+#undef SLUB_DEBUG_CMPXCHG
+
 /*
  * Mininum number of partial slabs. These will be left on the partial
  * lists even if they are empty. kmem_cache_shrink may reclaim them.
@@ -167,10 +169,11 @@ static inline int kmem_cache_debug(struct kmem_cache *s)
 
 #define OO_SHIFT        16
 #define OO_MASK         ((1 << OO_SHIFT) - 1)
-#define MAX_OBJS_PER_PAGE       65535 /* since page.objects is u16 */
+#define MAX_OBJS_PER_PAGE       32767 /* since page.objects is u15 */
 
 /* Internal SLUB flags */
 #define __OBJECT_POISON         0x80000000UL /* Poison object */
+#define __CMPXCHG_DOUBLE        0x40000000UL /* Use cmpxchg_double */
 
 static int kmem_size = sizeof(struct kmem_cache);
 
@@ -343,11 +346,99 @@ static inline int oo_objects(struct kmem_cache_order_objects x)
         return x.x & OO_MASK;
 }
 
+/*
+ * Per slab locking using the pagelock
+ */
+static __always_inline void slab_lock(struct page *page)
+{
+        bit_spin_lock(PG_locked, &page->flags);
+}
+
+static __always_inline void slab_unlock(struct page *page)
+{
+        __bit_spin_unlock(PG_locked, &page->flags);
+}
+
+/* Interrupts must be disabled (for the fallback code to work right) */
+static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
+                void *freelist_old, unsigned long counters_old,
+                void *freelist_new, unsigned long counters_new,
+                const char *n)
+{
+        VM_BUG_ON(!irqs_disabled());
+#ifdef CONFIG_CMPXCHG_DOUBLE
+        if (s->flags & __CMPXCHG_DOUBLE) {
+                if (cmpxchg_double(&page->freelist,
+                        freelist_old, counters_old,
+                        freelist_new, counters_new))
+                return 1;
+        } else
+#endif
+        {
+                slab_lock(page);
+                if (page->freelist == freelist_old && page->counters == counters_old) {
+                        page->freelist = freelist_new;
+                        page->counters = counters_new;
+                        slab_unlock(page);
+                        return 1;
+                }
+                slab_unlock(page);
+        }
+
+        cpu_relax();
+        stat(s, CMPXCHG_DOUBLE_FAIL);
+
+#ifdef SLUB_DEBUG_CMPXCHG
+        printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
+#endif
+
+        return 0;
+}
+
+static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
+                void *freelist_old, unsigned long counters_old,
+                void *freelist_new, unsigned long counters_new,
+                const char *n)
+{
+#ifdef CONFIG_CMPXCHG_DOUBLE
+        if (s->flags & __CMPXCHG_DOUBLE) {
+                if (cmpxchg_double(&page->freelist,
+                        freelist_old, counters_old,
+                        freelist_new, counters_new))
+                return 1;
+        } else
+#endif
+        {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                slab_lock(page);
+                if (page->freelist == freelist_old && page->counters == counters_old) {
+                        page->freelist = freelist_new;
+                        page->counters = counters_new;
+                        slab_unlock(page);
+                        local_irq_restore(flags);
+                        return 1;
+                }
+                slab_unlock(page);
+                local_irq_restore(flags);
+        }
+
+        cpu_relax();
+        stat(s, CMPXCHG_DOUBLE_FAIL);
+
+#ifdef SLUB_DEBUG_CMPXCHG
+        printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
+#endif
+
+        return 0;
+}
+
 #ifdef CONFIG_SLUB_DEBUG
 /*
  * Determine a map of object in use on a page.
  *
- * Slab lock or node listlock must be held to guarantee that the page does
+ * Node listlock must be held to guarantee that the page does
  * not vanish from under us.
  */
 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
@@ -838,10 +929,11 @@ static int check_slab(struct kmem_cache *s, struct page *page)
 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 {
         int nr = 0;
-        void *fp = page->freelist;
+        void *fp;
         void *object = NULL;
         unsigned long max_objects;
 
+        fp = page->freelist;
         while (fp && nr <= page->objects) {
                 if (fp == search)
                         return 1;
@@ -946,26 +1038,27 @@ static inline void slab_free_hook(struct kmem_cache *s, void *x)
 
 /*
  * Tracking of fully allocated slabs for debugging purposes.
+ *
+ * list_lock must be held.
  */
-static void add_full(struct kmem_cache_node *n, struct page *page)
+static void add_full(struct kmem_cache *s,
+        struct kmem_cache_node *n, struct page *page)
 {
-        spin_lock(&n->list_lock);
+        if (!(s->flags & SLAB_STORE_USER))
+                return;
+
         list_add(&page->lru, &n->full);
-        spin_unlock(&n->list_lock);
 }
 
+/*
+ * list_lock must be held.
+ */
 static void remove_full(struct kmem_cache *s, struct page *page)
 {
-        struct kmem_cache_node *n;
-
         if (!(s->flags & SLAB_STORE_USER))
                 return;
 
-        n = get_node(s, page_to_nid(page));
-
-        spin_lock(&n->list_lock);
         list_del(&page->lru);
-        spin_unlock(&n->list_lock);
 }
 
 /* Tracking of the number of slabs for debugging purposes */
@@ -1021,11 +1114,6 @@ static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *pa
         if (!check_slab(s, page))
                 goto bad;
 
-        if (!on_freelist(s, page, object)) {
-                object_err(s, page, object, "Object already allocated");
-                goto bad;
-        }
-
         if (!check_valid_pointer(s, page, object)) {
                 object_err(s, page, object, "Freelist Pointer check fails");
                 goto bad;
@@ -1058,6 +1146,12 @@ bad:
 static noinline int free_debug_processing(struct kmem_cache *s,
                  struct page *page, void *object, unsigned long addr)
 {
+        unsigned long flags;
+        int rc = 0;
+
+        local_irq_save(flags);
+        slab_lock(page);
+
         if (!check_slab(s, page))
                 goto fail;
 
@@ -1072,7 +1166,7 @@ static noinline int free_debug_processing(struct kmem_cache *s,
         }
 
         if (!check_object(s, page, object, SLUB_RED_ACTIVE))
-                return 0;
+                goto out;
 
         if (unlikely(s != page->slab)) {
                 if (!PageSlab(page)) {
@@ -1089,18 +1183,19 @@ static noinline int free_debug_processing(struct kmem_cache *s,
                 goto fail;
         }
 
-        /* Special debug activities for freeing objects */
-        if (!PageSlubFrozen(page) && !page->freelist)
-                remove_full(s, page);
         if (s->flags & SLAB_STORE_USER)
                 set_track(s, object, TRACK_FREE, addr);
         trace(s, page, object, 0);
         init_object(s, object, SLUB_RED_INACTIVE);
-        return 1;
+        rc = 1;
+out:
+        slab_unlock(page);
+        local_irq_restore(flags);
+        return rc;
 
 fail:
         slab_fix(s, "Object at 0x%p not freed", object);
-        return 0;
+        goto out;
 }
 
 static int __init setup_slub_debug(char *str)
@@ -1200,7 +1295,9 @@ static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
                         { return 1; }
 static inline int check_object(struct kmem_cache *s, struct page *page,
                         void *object, u8 val) { return 1; }
-static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
+static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
+                                        struct page *page) {}
+static inline void remove_full(struct kmem_cache *s, struct page *page) {}
 static inline unsigned long kmem_cache_flags(unsigned long objsize,
         unsigned long flags, const char *name,
         void (*ctor)(void *))
@@ -1252,6 +1349,11 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
         struct kmem_cache_order_objects oo = s->oo;
         gfp_t alloc_gfp;
 
+        flags &= gfp_allowed_mask;
+
+        if (flags & __GFP_WAIT)
+                local_irq_enable();
+
         flags |= s->allocflags;
 
         /*
@@ -1268,12 +1370,17 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
                  * Try a lower order alloc if possible
                  */
                 page = alloc_slab_page(flags, node, oo);
-                if (!page)
-                        return NULL;
 
-                stat(s, ORDER_FALLBACK);
+                if (page)
+                        stat(s, ORDER_FALLBACK);
         }
 
+        if (flags & __GFP_WAIT)
+                local_irq_disable();
+
+        if (!page)
+                return NULL;
+
         if (kmemcheck_enabled
                 && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
                 int pages = 1 << oo_order(oo);
@@ -1341,6 +1448,7 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 
         page->freelist = start;
         page->inuse = 0;
+        page->frozen = 1;
 out:
         return page;
 }
@@ -1418,77 +1526,87 @@ static void discard_slab(struct kmem_cache *s, struct page *page)
 }
 
 /*
- * Per slab locking using the pagelock
- */
-static __always_inline void slab_lock(struct page *page)
-{
-        bit_spin_lock(PG_locked, &page->flags);
-}
-
-static __always_inline void slab_unlock(struct page *page)
-{
-        __bit_spin_unlock(PG_locked, &page->flags);
-}
-
-static __always_inline int slab_trylock(struct page *page)
-{
-        int rc = 1;
-
-        rc = bit_spin_trylock(PG_locked, &page->flags);
-        return rc;
-}
-
-/*
- * Management of partially allocated slabs
+ * Management of partially allocated slabs.
+ *
+ * list_lock must be held.
  */
-static void add_partial(struct kmem_cache_node *n,
+static inline void add_partial(struct kmem_cache_node *n,
                                 struct page *page, int tail)
 {
-        spin_lock(&n->list_lock);
         n->nr_partial++;
         if (tail)
                 list_add_tail(&page->lru, &n->partial);
         else
                 list_add(&page->lru, &n->partial);
-        spin_unlock(&n->list_lock);
 }
 
-static inline void __remove_partial(struct kmem_cache_node *n,
+/*
+ * list_lock must be held.
+ */
+static inline void remove_partial(struct kmem_cache_node *n,
                                         struct page *page)
 {
         list_del(&page->lru);
         n->nr_partial--;
 }
 
-static void remove_partial(struct kmem_cache *s, struct page *page)
-{
-        struct kmem_cache_node *n = get_node(s, page_to_nid(page));
-
-        spin_lock(&n->list_lock);
-        __remove_partial(n, page);
-        spin_unlock(&n->list_lock);
-}
-
 /*
- * Lock slab and remove from the partial list.
+ * Lock slab, remove from the partial list and put the object into the
+ * per cpu freelist.
  *
  * Must hold list_lock.
  */
-static inline int lock_and_freeze_slab(struct kmem_cache_node *n,
-                                                        struct page *page)
+static inline int acquire_slab(struct kmem_cache *s,
+                struct kmem_cache_node *n, struct page *page)
 {
-        if (slab_trylock(page)) {
-                __remove_partial(n, page);
-                __SetPageSlubFrozen(page);
+        void *freelist;
+        unsigned long counters;
+        struct page new;
+
+        /*
+         * Zap the freelist and set the frozen bit.
+         * The old freelist is the list of objects for the
+         * per cpu allocation list.
+         */
+        do {
+                freelist = page->freelist;
+                counters = page->counters;
+                new.counters = counters;
+                new.inuse = page->objects;
+
+                VM_BUG_ON(new.frozen);
+                new.frozen = 1;
+
+        } while (!__cmpxchg_double_slab(s, page,
+                        freelist, counters,
+                        NULL, new.counters,
+                        "lock and freeze"));
+
+        remove_partial(n, page);
+
+        if (freelist) {
+                /* Populate the per cpu freelist */
+                this_cpu_write(s->cpu_slab->freelist, freelist);
+                this_cpu_write(s->cpu_slab->page, page);
+                this_cpu_write(s->cpu_slab->node, page_to_nid(page));
                 return 1;
+        } else {
+                /*
+                 * Slab page came from the wrong list. No object to allocate
+                 * from. Put it onto the correct list and continue partial
+                 * scan.
+                 */
+                printk(KERN_ERR "SLUB: %s : Page without available objects on"
+                        " partial list\n", s->name);
+                return 0;
         }
-        return 0;
 }
 
 /*
  * Try to allocate a partial slab from a specific node.
  */
-static struct page *get_partial_node(struct kmem_cache_node *n)
+static struct page *get_partial_node(struct kmem_cache *s,
+                                        struct kmem_cache_node *n)
 {
         struct page *page;
 
@@ -1503,7 +1621,7 @@ static struct page *get_partial_node(struct kmem_cache_node *n)
 
         spin_lock(&n->list_lock);
         list_for_each_entry(page, &n->partial, lru)
-                if (lock_and_freeze_slab(n, page))
+                if (acquire_slab(s, n, page))
                         goto out;
         page = NULL;
 out:
@@ -1554,7 +1672,7 @@ static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
 
                 if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
                                 n->nr_partial > s->min_partial) {
-                        page = get_partial_node(n);
+                        page = get_partial_node(s, n);
                         if (page) {
                                 put_mems_allowed();
                                 return page;
@@ -1574,60 +1692,13 @@ static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
         struct page *page;
         int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
 
-        page = get_partial_node(get_node(s, searchnode));
+        page = get_partial_node(s, get_node(s, searchnode));
         if (page || node != NUMA_NO_NODE)
                 return page;
 
         return get_any_partial(s, flags);
 }
 
-/*
- * Move a page back to the lists.
- *
- * Must be called with the slab lock held.
- *
- * On exit the slab lock will have been dropped.
- */
-static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
-        __releases(bitlock)
-{
-        struct kmem_cache_node *n = get_node(s, page_to_nid(page));
-
-        __ClearPageSlubFrozen(page);
-        if (page->inuse) {
-
-                if (page->freelist) {
-                        add_partial(n, page, tail);
-                        stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
-                } else {
-                        stat(s, DEACTIVATE_FULL);
-                        if (kmem_cache_debug(s) && (s->flags & SLAB_STORE_USER))
-                                add_full(n, page);
-                }
-                slab_unlock(page);
-        } else {
-                stat(s, DEACTIVATE_EMPTY);
-                if (n->nr_partial < s->min_partial) {
-                        /*
-                         * Adding an empty slab to the partial slabs in order
-                         * to avoid page allocator overhead. This slab needs
-                         * to come after the other slabs with objects in
-                         * so that the others get filled first. That way the
-                         * size of the partial list stays small.
-                         *
-                         * kmem_cache_shrink can reclaim any empty slabs from
-                         * the partial list.
-                         */
-                        add_partial(n, page, 1);
-                        slab_unlock(page);
-                } else {
-                        slab_unlock(page);
-                        stat(s, FREE_SLAB);
-                        discard_slab(s, page);
-                }
-        }
-}
-
 #ifdef CONFIG_PREEMPT
 /*
  * Calculate the next globally unique transaction for disambiguiation
@@ -1697,42 +1768,161 @@ void init_kmem_cache_cpus(struct kmem_cache *s)
 /*
  * Remove the cpu slab
  */
+
+/*
+ * Remove the cpu slab
+ */
 static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
-        __releases(bitlock)
 {
+        enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
         struct page *page = c->page;
-        int tail = 1;
-
-        if (page->freelist)
+        struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+        int lock = 0;
+        enum slab_modes l = M_NONE, m = M_NONE;
+        void *freelist;
+        void *nextfree;
+        int tail = 0;
+        struct page new;
+        struct page old;
+
+        if (page->freelist) {
                 stat(s, DEACTIVATE_REMOTE_FREES);
+                tail = 1;
+        }
+
+        c->tid = next_tid(c->tid);
+        c->page = NULL;
+        freelist = c->freelist;
+        c->freelist = NULL;
+
+        /*
+         * Stage one: Free all available per cpu objects back
+         * to the page freelist while it is still frozen. Leave the
+         * last one.
+         *
+         * There is no need to take the list->lock because the page
+         * is still frozen.
+         */
+        while (freelist && (nextfree = get_freepointer(s, freelist))) {
+                void *prior;
+                unsigned long counters;
+
+                do {
+                        prior = page->freelist;
+                        counters = page->counters;
+                        set_freepointer(s, freelist, prior);
+                        new.counters = counters;
+                        new.inuse--;
+                        VM_BUG_ON(!new.frozen);
+
+                } while (!__cmpxchg_double_slab(s, page,
+                        prior, counters,
+                        freelist, new.counters,
+                        "drain percpu freelist"));
+
+                freelist = nextfree;
+        }
+
         /*
-         * Merge cpu freelist into slab freelist. Typically we get here
-         * because both freelists are empty. So this is unlikely
-         * to occur.
+         * Stage two: Ensure that the page is unfrozen while the
+         * list presence reflects the actual number of objects
+         * during unfreeze.
+         *
+         * We setup the list membership and then perform a cmpxchg
+         * with the count. If there is a mismatch then the page
+         * is not unfrozen but the page is on the wrong list.
+         *
+         * Then we restart the process which may have to remove
+         * the page from the list that we just put it on again
+         * because the number of objects in the slab may have
+         * changed.
          */
-        while (unlikely(c->freelist)) {
-                void **object;
+redo:
 
-                tail = 0;       /* Hot objects. Put the slab first */
+        old.freelist = page->freelist;
+        old.counters = page->counters;
+        VM_BUG_ON(!old.frozen);
 
-                /* Retrieve object from cpu_freelist */
-                object = c->freelist;
-                c->freelist = get_freepointer(s, c->freelist);
+        /* Determine target state of the slab */
+        new.counters = old.counters;
+        if (freelist) {
+                new.inuse--;
+                set_freepointer(s, freelist, old.freelist);
+                new.freelist = freelist;
+        } else
+                new.freelist = old.freelist;
+
+        new.frozen = 0;
+
+        if (!new.inuse && n->nr_partial < s->min_partial)
+                m = M_FREE;
+        else if (new.freelist) {
+                m = M_PARTIAL;
+                if (!lock) {
+                        lock = 1;
+                        /*
+                         * Taking the spinlock removes the possiblity
+                         * that acquire_slab() will see a slab page that
+                         * is frozen
+                         */
+                        spin_lock(&n->list_lock);
+                }
+        } else {
+                m = M_FULL;
+                if (kmem_cache_debug(s) && !lock) {
+                        lock = 1;
+                        /*
+                         * This also ensures that the scanning of full
+                         * slabs from diagnostic functions will not see
+                         * any frozen slabs.
+                         */
+                        spin_lock(&n->list_lock);
+                }
+        }
+
+        if (l != m) {
+
+                if (l == M_PARTIAL)
+
+                        remove_partial(n, page);
+
+                else if (l == M_FULL)
+
+                        remove_full(s, page);
+
+                if (m == M_PARTIAL) {
+
+                        add_partial(n, page, tail);
+                        stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
+
+                } else if (m == M_FULL) {
 
-                /* And put onto the regular freelist */
-                set_freepointer(s, object, page->freelist);
-                page->freelist = object;
-                page->inuse--;
+                        stat(s, DEACTIVATE_FULL);
+                        add_full(s, n, page);
+
+                }
+        }
+
+        l = m;
+        if (!__cmpxchg_double_slab(s, page,
+                                old.freelist, old.counters,
+                                new.freelist, new.counters,
+                                "unfreezing slab"))
+                goto redo;
+
+        if (lock)
+                spin_unlock(&n->list_lock);
+
+        if (m == M_FREE) {
+                stat(s, DEACTIVATE_EMPTY);
+                discard_slab(s, page);
+                stat(s, FREE_SLAB);
         }
-        c->page = NULL;
-        c->tid = next_tid(c->tid);
-        unfreeze_slab(s, page, tail);
 }
 
 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 {
         stat(s, CPUSLAB_FLUSH);
-        slab_lock(c->page);
         deactivate_slab(s, c);
 }
 
@@ -1861,6 +2051,8 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
         void **object;
         struct page *page;
         unsigned long flags;
+        struct page new;
+        unsigned long counters;
 
         local_irq_save(flags);
 #ifdef CONFIG_PREEMPT
@@ -1879,72 +2071,97 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
         if (!page)
                 goto new_slab;
 
-        slab_lock(page);
-        if (unlikely(!node_match(c, node)))
-                goto another_slab;
+        if (unlikely(!node_match(c, node))) {
+                stat(s, ALLOC_NODE_MISMATCH);
+                deactivate_slab(s, c);
+                goto new_slab;
+        }
+
+        stat(s, ALLOC_SLOWPATH);
+
+        do {
+                object = page->freelist;
+                counters = page->counters;
+                new.counters = counters;
+                VM_BUG_ON(!new.frozen);
+
+                /*
+                 * If there is no object left then we use this loop to
+                 * deactivate the slab which is simple since no objects
+                 * are left in the slab and therefore we do not need to
+                 * put the page back onto the partial list.
+                 *
+                 * If there are objects left then we retrieve them
+                 * and use them to refill the per cpu queue.
+                */
+
+                new.inuse = page->objects;
+                new.frozen = object != NULL;
+
+        } while (!__cmpxchg_double_slab(s, page,
+                        object, counters,
+                        NULL, new.counters,
+                        "__slab_alloc"));
+
+        if (unlikely(!object)) {
+                c->page = NULL;
+                stat(s, DEACTIVATE_BYPASS);
+                goto new_slab;
+        }
 
         stat(s, ALLOC_REFILL);
 
 load_freelist:
-        object = page->freelist;
-        if (unlikely(!object))
-                goto another_slab;
-        if (kmem_cache_debug(s))
-                goto debug;
-
+        VM_BUG_ON(!page->frozen);
         c->freelist = get_freepointer(s, object);
-        page->inuse = page->objects;
-        page->freelist = NULL;
-
-        slab_unlock(page);
         c->tid = next_tid(c->tid);
         local_irq_restore(flags);
-        stat(s, ALLOC_SLOWPATH);
         return object;
 
-another_slab:
-        deactivate_slab(s, c);
-
 new_slab:
         page = get_partial(s, gfpflags, node);
         if (page) {
                 stat(s, ALLOC_FROM_PARTIAL);
-                c->node = page_to_nid(page);
-                c->page = page;
+                object = c->freelist;
+
+                if (kmem_cache_debug(s))
+                        goto debug;
                 goto load_freelist;
         }
 
-        gfpflags &= gfp_allowed_mask;
-        if (gfpflags & __GFP_WAIT)
-                local_irq_enable();
-
         page = new_slab(s, gfpflags, node);
 
-        if (gfpflags & __GFP_WAIT)
-                local_irq_disable();
-
         if (page) {
                 c = __this_cpu_ptr(s->cpu_slab);
-                stat(s, ALLOC_SLAB);
                 if (c->page)
                         flush_slab(s, c);
 
-                slab_lock(page);
-                __SetPageSlubFrozen(page);
+                /*
+                 * No other reference to the page yet so we can
+                 * muck around with it freely without cmpxchg
+                 */
+                object = page->freelist;
+                page->freelist = NULL;
+                page->inuse = page->objects;
+
+                stat(s, ALLOC_SLAB);
                 c->node = page_to_nid(page);
                 c->page = page;
+
+                if (kmem_cache_debug(s))
+                        goto debug;
                 goto load_freelist;
         }
         if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
                 slab_out_of_memory(s, gfpflags, node);
         local_irq_restore(flags);
         return NULL;
+
 debug:
-        if (!alloc_debug_processing(s, page, object, addr))
-                goto another_slab;
+        if (!object || !alloc_debug_processing(s, page, object, addr))
+                goto new_slab;
 
-        page->inuse++;
-        page->freelist = get_freepointer(s, object);
+        c->freelist = get_freepointer(s, object);
         deactivate_slab(s, c);
         c->page = NULL;
         c->node = NUMA_NO_NODE;
@@ -2096,40 +2313,75 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 {
         void *prior;
         void **object = (void *)x;
-        unsigned long flags;
+        int was_frozen;
+        int inuse;
+        struct page new;
+        unsigned long counters;
+        struct kmem_cache_node *n = NULL;
+        unsigned long uninitialized_var(flags);
 
-        local_irq_save(flags);
-        slab_lock(page);
         stat(s, FREE_SLOWPATH);
 
         if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
-                goto out_unlock;
+                return;
 
-        prior = page->freelist;
-        set_freepointer(s, object, prior);
-        page->freelist = object;
-        page->inuse--;
+        do {
+                prior = page->freelist;
+                counters = page->counters;
+                set_freepointer(s, object, prior);
+                new.counters = counters;
+                was_frozen = new.frozen;
+                new.inuse--;
+                if ((!new.inuse || !prior) && !was_frozen && !n) {
+                        n = get_node(s, page_to_nid(page));
+                        /*
+                         * Speculatively acquire the list_lock.
+                         * If the cmpxchg does not succeed then we may
+                         * drop the list_lock without any processing.
+                         *
+                         * Otherwise the list_lock will synchronize with
+                         * other processors updating the list of slabs.
+                         */
+                        spin_lock_irqsave(&n->list_lock, flags);
+                }
+                inuse = new.inuse;
 
-        if (unlikely(PageSlubFrozen(page))) {
-                stat(s, FREE_FROZEN);
-                goto out_unlock;
-        }
+        } while (!cmpxchg_double_slab(s, page,
+                prior, counters,
+                object, new.counters,
+                "__slab_free"));
 
-        if (unlikely(!page->inuse))
-                goto slab_empty;
+        if (likely(!n)) {
+                /*
+                 * The list lock was not taken therefore no list
+                 * activity can be necessary.
+                 */
+                if (was_frozen)
+                        stat(s, FREE_FROZEN);
+                return;
+        }
 
         /*
-         * Objects left in the slab. If it was not on the partial list before
-         * then add it.
+         * was_frozen may have been set after we acquired the list_lock in
+         * an earlier loop. So we need to check it here again.
          */
-        if (unlikely(!prior)) {
-                add_partial(get_node(s, page_to_nid(page)), page, 1);
-                stat(s, FREE_ADD_PARTIAL);
-        }
+        if (was_frozen)
+                stat(s, FREE_FROZEN);
+        else {
+                if (unlikely(!inuse && n->nr_partial > s->min_partial))
+                        goto slab_empty;
 
-out_unlock:
-        slab_unlock(page);
-        local_irq_restore(flags);
+                /*
+                 * Objects left in the slab. If it was not on the partial list before
+                 * then add it.
+                 */
+                if (unlikely(!prior)) {
+                        remove_full(s, page);
+                        add_partial(n, page, 0);
+                        stat(s, FREE_ADD_PARTIAL);
+                }
+        }
+        spin_unlock_irqrestore(&n->list_lock, flags);
         return;
 
 slab_empty:
@@ -2137,11 +2389,11 @@ slab_empty:
                 /*
                  * Slab still on the partial list.
                  */
-                remove_partial(s, page);
+                remove_partial(n, page);
                 stat(s, FREE_REMOVE_PARTIAL);
         }
-        slab_unlock(page);
-        local_irq_restore(flags);
+
+        spin_unlock_irqrestore(&n->list_lock, flags);
         stat(s, FREE_SLAB);
         discard_slab(s, page);
 }
@@ -2415,7 +2667,6 @@ static void early_kmem_cache_node_alloc(int node)
 {
         struct page *page;
         struct kmem_cache_node *n;
-        unsigned long flags;
 
         BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
 
@@ -2433,6 +2684,7 @@ static void early_kmem_cache_node_alloc(int node)
         BUG_ON(!n);
         page->freelist = get_freepointer(kmem_cache_node, n);
         page->inuse++;
+        page->frozen = 0;
         kmem_cache_node->node[node] = n;
 #ifdef CONFIG_SLUB_DEBUG
         init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
@@ -2441,14 +2693,7 @@ static void early_kmem_cache_node_alloc(int node)
         init_kmem_cache_node(n, kmem_cache_node);
         inc_slabs_node(kmem_cache_node, node, page->objects);
 
-        /*
-         * lockdep requires consistent irq usage for each lock
-         * so even though there cannot be a race this early in
-         * the boot sequence, we still disable irqs.
-         */
-        local_irq_save(flags);
         add_partial(n, page, 0);
-        local_irq_restore(flags);
 }
 
 static void free_kmem_cache_nodes(struct kmem_cache *s)
@@ -2654,6 +2899,12 @@ static int kmem_cache_open(struct kmem_cache *s,
                 }
         }
 
+#ifdef CONFIG_CMPXCHG_DOUBLE
+        if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
+                /* Enable fast mode */
+                s->flags |= __CMPXCHG_DOUBLE;
+#endif
+
         /*
          * The larger the object size is, the more pages we want on the partial
          * list to avoid pounding the page allocator excessively.
@@ -2726,7 +2977,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
         spin_lock_irqsave(&n->list_lock, flags);
         list_for_each_entry_safe(page, h, &n->partial, lru) {
                 if (!page->inuse) {
-                        __remove_partial(n, page);
+                        remove_partial(n, page);
                         discard_slab(s, page);
                 } else {
                         list_slab_objects(s, page,
@@ -3094,14 +3345,8 @@ int kmem_cache_shrink(struct kmem_cache *s)
                  * list_lock. page->inuse here is the upper limit.
                  */
                 list_for_each_entry_safe(page, t, &n->partial, lru) {
-                        if (!page->inuse && slab_trylock(page)) {
-                                /*
-                                 * Must hold slab lock here because slab_free
-                                 * may have freed the last object and be
-                                 * waiting to release the slab.
-                                 */
-                                __remove_partial(n, page);
-                                slab_unlock(page);
+                        if (!page->inuse) {
+                                remove_partial(n, page);
                                 discard_slab(s, page);
                         } else {
                                 list_move(&page->lru,
@@ -3689,12 +3934,9 @@ static int validate_slab(struct kmem_cache *s, struct page *page,
 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
                                                 unsigned long *map)
 {
-        if (slab_trylock(page)) {
-                validate_slab(s, page, map);
-                slab_unlock(page);
-        } else
-                printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
-                        s->name, page);
+        slab_lock(page);
+        validate_slab(s, page, map);
+        slab_unlock(page);
 }
 
 static int validate_slab_node(struct kmem_cache *s,
@@ -4342,8 +4584,10 @@ static ssize_t sanity_checks_store(struct kmem_cache *s,
                                 const char *buf, size_t length)
 {
         s->flags &= ~SLAB_DEBUG_FREE;
-        if (buf[0] == '1')
+        if (buf[0] == '1') {
+                s->flags &= ~__CMPXCHG_DOUBLE;
                 s->flags |= SLAB_DEBUG_FREE;
+        }
         return length;
 }
 SLAB_ATTR(sanity_checks);
@@ -4357,8 +4601,10 @@ static ssize_t trace_store(struct kmem_cache *s, const char *buf,
                                                         size_t length)
 {
         s->flags &= ~SLAB_TRACE;
-        if (buf[0] == '1')
+        if (buf[0] == '1') {
+                s->flags &= ~__CMPXCHG_DOUBLE;
                 s->flags |= SLAB_TRACE;
+        }
         return length;
 }
 SLAB_ATTR(trace);
@@ -4375,8 +4621,10 @@ static ssize_t red_zone_store(struct kmem_cache *s,
                 return -EBUSY;
 
         s->flags &= ~SLAB_RED_ZONE;
-        if (buf[0] == '1')
+        if (buf[0] == '1') {
+                s->flags &= ~__CMPXCHG_DOUBLE;
                 s->flags |= SLAB_RED_ZONE;
+        }
         calculate_sizes(s, -1);
         return length;
 }
@@ -4394,8 +4642,10 @@ static ssize_t poison_store(struct kmem_cache *s,
                 return -EBUSY;
 
         s->flags &= ~SLAB_POISON;
-        if (buf[0] == '1')
+        if (buf[0] == '1') {
+                s->flags &= ~__CMPXCHG_DOUBLE;
                 s->flags |= SLAB_POISON;
+        }
         calculate_sizes(s, -1);
         return length;
 }
@@ -4413,8 +4663,10 @@ static ssize_t store_user_store(struct kmem_cache *s,
                 return -EBUSY;
 
         s->flags &= ~SLAB_STORE_USER;
-        if (buf[0] == '1')
+        if (buf[0] == '1') {
+                s->flags &= ~__CMPXCHG_DOUBLE;
                 s->flags |= SLAB_STORE_USER;
+        }
         calculate_sizes(s, -1);
         return length;
 }
@@ -4579,6 +4831,7 @@ STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
 STAT_ATTR(ALLOC_SLAB, alloc_slab);
 STAT_ATTR(ALLOC_REFILL, alloc_refill);
+STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
 STAT_ATTR(FREE_SLAB, free_slab);
 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
@@ -4586,7 +4839,10 @@ STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
+STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
 STAT_ATTR(ORDER_FALLBACK, order_fallback);
+STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
+STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
 #endif
 
 static struct attribute *slab_attrs[] = {
@@ -4636,6 +4892,7 @@ static struct attribute *slab_attrs[] = {
         &alloc_from_partial_attr.attr,
         &alloc_slab_attr.attr,
         &alloc_refill_attr.attr,
+        &alloc_node_mismatch_attr.attr,
         &free_slab_attr.attr,
         &cpuslab_flush_attr.attr,
         &deactivate_full_attr.attr,
@@ -4643,7 +4900,10 @@ static struct attribute *slab_attrs[] = {
         &deactivate_to_head_attr.attr,
         &deactivate_to_tail_attr.attr,
         &deactivate_remote_frees_attr.attr,
+        &deactivate_bypass_attr.attr,
         &order_fallback_attr.attr,
+        &cmpxchg_double_fail_attr.attr,
+        &cmpxchg_double_cpu_fail_attr.attr,
 #endif
 #ifdef CONFIG_FAILSLAB
         &failslab_attr.attr,