Merge branch 'slub/lockless' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg...
authorLinus Torvalds <torvalds@linux-foundation.org>
Sat, 30 Jul 2011 18:21:48 +0000 (08:21 -1000)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 30 Jul 2011 18:21:48 +0000 (08:21 -1000)
* '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
  ...

include/linux/mm_types.h
include/linux/page-flags.h
include/linux/slub_def.h
mm/slub.c
tools/slub/slabinfo.c

index 027935c..774b895 100644 (file)
@@ -30,23 +30,61 @@ struct address_space;
  * moment. Note that we have no way to track which tasks are using
  * a page, though if it is a pagecache page, rmap structures can tell us
  * who is mapping it.
+ *
+ * The objects in struct page are organized in double word blocks in
+ * order to allows us to use atomic double word operations on portions
+ * of struct page. That is currently only used by slub but the arrangement
+ * allows the use of atomic double word operations on the flags/mapping
+ * and lru list pointers also.
  */
 struct page {
+       /* First double word block */
        unsigned long flags;            /* Atomic flags, some possibly
                                         * updated asynchronously */
-       atomic_t _count;                /* Usage count, see below. */
-       union {
-               atomic_t _mapcount;     /* Count of ptes mapped in mms,
-                                        * to show when page is mapped
-                                        * & limit reverse map searches.
+       struct address_space *mapping;  /* If low bit clear, points to
+                                        * inode address_space, or NULL.
+                                        * If page mapped as anonymous
+                                        * memory, low bit is set, and
+                                        * it points to anon_vma object:
+                                        * see PAGE_MAPPING_ANON below.
                                         */
-               struct {                /* SLUB */
-                       u16 inuse;
-                       u16 objects;
+       /* Second double word */
+       struct {
+               union {
+                       pgoff_t index;          /* Our offset within mapping. */
+                       void *freelist;         /* slub first free object */
+               };
+
+               union {
+                       /* Used for cmpxchg_double in slub */
+                       unsigned long counters;
+
+                       struct {
+
+                               union {
+                                       atomic_t _mapcount;     /* Count of ptes mapped in mms,
+                                                        * to show when page is mapped
+                                                        * & limit reverse map searches.
+                                                        */
+
+                                       struct {
+                                               unsigned inuse:16;
+                                               unsigned objects:15;
+                                               unsigned frozen:1;
+                                       };
+                               };
+                               atomic_t _count;                /* Usage count, see below. */
+                       };
                };
        };
+
+       /* Third double word block */
+       struct list_head lru;           /* Pageout list, eg. active_list
+                                        * protected by zone->lru_lock !
+                                        */
+
+       /* Remainder is not double word aligned */
        union {
-           struct {
                unsigned long private;          /* Mapping-private opaque data:
                                                 * usually used for buffer_heads
                                                 * if PagePrivate set; used for
@@ -54,27 +92,13 @@ struct page {
                                                 * indicates order in the buddy
                                                 * system if PG_buddy is set.
                                                 */
-               struct address_space *mapping;  /* If low bit clear, points to
-                                                * inode address_space, or NULL.
-                                                * If page mapped as anonymous
-                                                * memory, low bit is set, and
-                                                * it points to anon_vma object:
-                                                * see PAGE_MAPPING_ANON below.
-                                                */
-           };
 #if USE_SPLIT_PTLOCKS
-           spinlock_t ptl;
+               spinlock_t ptl;
 #endif
-           struct kmem_cache *slab;    /* SLUB: Pointer to slab */
-           struct page *first_page;    /* Compound tail pages */
-       };
-       union {
-               pgoff_t index;          /* Our offset within mapping. */
-               void *freelist;         /* SLUB: freelist req. slab lock */
+               struct kmem_cache *slab;        /* SLUB: Pointer to slab */
+               struct page *first_page;        /* Compound tail pages */
        };
-       struct list_head lru;           /* Pageout list, eg. active_list
-                                        * protected by zone->lru_lock !
-                                        */
+
        /*
         * On machines where all RAM is mapped into kernel address space,
         * we can simply calculate the virtual address. On machines with
@@ -100,7 +124,16 @@ struct page {
         */
        void *shadow;
 #endif
-};
+}
+/*
+ * If another subsystem starts using the double word pairing for atomic
+ * operations on struct page then it must change the #if to ensure
+ * proper alignment of the page struct.
+ */
+#if defined(CONFIG_SLUB) && defined(CONFIG_CMPXCHG_LOCAL)
+       __attribute__((__aligned__(2*sizeof(unsigned long))))
+#endif
+;
 
 typedef unsigned long __nocast vm_flags_t;
 
index 3e5a1b1..e90a673 100644 (file)
@@ -124,9 +124,6 @@ enum pageflags {
 
        /* SLOB */
        PG_slob_free = PG_private,
-
-       /* SLUB */
-       PG_slub_frozen = PG_active,
 };
 
 #ifndef __GENERATING_BOUNDS_H
@@ -212,8 +209,6 @@ PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
 
 __PAGEFLAG(SlobFree, slob_free)
 
-__PAGEFLAG(SlubFrozen, slub_frozen)
-
 /*
  * Private page markings that may be used by the filesystem that owns the page
  * for its own purposes.
index 4b35c06..f58d641 100644 (file)
@@ -24,6 +24,7 @@ enum stat_item {
        ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from partial list */
        ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
        ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
+       ALLOC_NODE_MISMATCH,    /* Switching cpu slab */
        FREE_SLAB,              /* Slab freed to the page allocator */
        CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
        DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
@@ -31,8 +32,10 @@ enum stat_item {
        DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
        DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
        DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
+       DEACTIVATE_BYPASS,      /* Implicit deactivation */
        ORDER_FALLBACK,         /* Number of times fallback was necessary */
        CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
+       CMPXCHG_DOUBLE_FAIL,    /* Number of times that cmpxchg double did not match */
        NR_SLUB_STAT_ITEMS };
 
 struct kmem_cache_cpu {
index f8f5e8e..eb5a8f9 100644 (file)
--- 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>
 
 /*
  * 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
  *   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
@@ -1694,45 +1765,164 @@ void init_kmem_cache_cpus(struct kmem_cache *s)
        for_each_possible_cpu(cpu)
                per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
 }
+/*
+ * 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,
index 516551c..868cc93 100644 (file)
@@ -2,8 +2,9 @@
  * Slabinfo: Tool to get reports about slabs
  *
  * (C) 2007 sgi, Christoph Lameter
+ * (C) 2011 Linux Foundation, Christoph Lameter
  *
- * Compile by:
+ * Compile with:
  *
  * gcc -o slabinfo slabinfo.c
  */
@@ -39,6 +40,8 @@ struct slabinfo {
        unsigned long cpuslab_flush, deactivate_full, deactivate_empty;
        unsigned long deactivate_to_head, deactivate_to_tail;
        unsigned long deactivate_remote_frees, order_fallback;
+       unsigned long cmpxchg_double_cpu_fail, cmpxchg_double_fail;
+       unsigned long alloc_node_mismatch, deactivate_bypass;
        int numa[MAX_NODES];
        int numa_partial[MAX_NODES];
 } slabinfo[MAX_SLABS];
@@ -99,7 +102,7 @@ static void fatal(const char *x, ...)
 
 static void usage(void)
 {
-       printf("slabinfo 5/7/2007. (c) 2007 sgi.\n\n"
+       printf("slabinfo 4/15/2011. (c) 2007 sgi/(c) 2011 Linux Foundation.\n\n"
                "slabinfo [-ahnpvtsz] [-d debugopts] [slab-regexp]\n"
                "-a|--aliases           Show aliases\n"
                "-A|--activity          Most active slabs first\n"
@@ -293,7 +296,7 @@ int line = 0;
 static void first_line(void)
 {
        if (show_activity)
-               printf("Name                   Objects      Alloc       Free   %%Fast Fallb O\n");
+               printf("Name                   Objects      Alloc       Free   %%Fast Fallb O CmpX   UL\n");
        else
                printf("Name                   Objects Objsize    Space "
                        "Slabs/Part/Cpu  O/S O %%Fr %%Ef Flg\n");
@@ -379,14 +382,14 @@ static void show_tracking(struct slabinfo *s)
        printf("\n%s: Kernel object allocation\n", s->name);
        printf("-----------------------------------------------------------------------\n");
        if (read_slab_obj(s, "alloc_calls"))
-               printf(buffer);
+               printf("%s", buffer);
        else
                printf("No Data\n");
 
        printf("\n%s: Kernel object freeing\n", s->name);
        printf("------------------------------------------------------------------------\n");
        if (read_slab_obj(s, "free_calls"))
-               printf(buffer);
+               printf("%s", buffer);
        else
                printf("No Data\n");
 
@@ -400,7 +403,7 @@ static void ops(struct slabinfo *s)
        if (read_slab_obj(s, "ops")) {
                printf("\n%s: kmem_cache operations\n", s->name);
                printf("--------------------------------------------\n");
-               printf(buffer);
+               printf("%s", buffer);
        } else
                printf("\n%s has no kmem_cache operations\n", s->name);
 }
@@ -462,19 +465,32 @@ static void slab_stats(struct slabinfo *s)
        if (s->cpuslab_flush)
                printf("Flushes %8lu\n", s->cpuslab_flush);
 
-       if (s->alloc_refill)
-               printf("Refill %8lu\n", s->alloc_refill);
-
        total = s->deactivate_full + s->deactivate_empty +
-                       s->deactivate_to_head + s->deactivate_to_tail;
-
-       if (total)
-               printf("Deactivate Full=%lu(%lu%%) Empty=%lu(%lu%%) "
-                       "ToHead=%lu(%lu%%) ToTail=%lu(%lu%%)\n",
-                       s->deactivate_full, (s->deactivate_full * 100) / total,
-                       s->deactivate_empty, (s->deactivate_empty * 100) / total,
-                       s->deactivate_to_head, (s->deactivate_to_head * 100) / total,
+                       s->deactivate_to_head + s->deactivate_to_tail + s->deactivate_bypass;
+
+       if (total) {
+               printf("\nSlab Deactivation             Ocurrences  %%\n");
+               printf("-------------------------------------------------\n");
+               printf("Slab full                     %7lu  %3lu%%\n",
+                       s->deactivate_full, (s->deactivate_full * 100) / total);
+               printf("Slab empty                    %7lu  %3lu%%\n",
+                       s->deactivate_empty, (s->deactivate_empty * 100) / total);
+               printf("Moved to head of partial list %7lu  %3lu%%\n",
+                       s->deactivate_to_head, (s->deactivate_to_head * 100) / total);
+               printf("Moved to tail of partial list %7lu  %3lu%%\n",
                        s->deactivate_to_tail, (s->deactivate_to_tail * 100) / total);
+               printf("Deactivation bypass           %7lu  %3lu%%\n",
+                       s->deactivate_bypass, (s->deactivate_bypass * 100) / total);
+               printf("Refilled from foreign frees   %7lu  %3lu%%\n",
+                       s->alloc_refill, (s->alloc_refill * 100) / total);
+               printf("Node mismatch                 %7lu  %3lu%%\n",
+                       s->alloc_node_mismatch, (s->alloc_node_mismatch * 100) / total);
+       }
+
+       if (s->cmpxchg_double_fail || s->cmpxchg_double_cpu_fail)
+               printf("\nCmpxchg_double Looping\n------------------------\n");
+               printf("Locked Cmpxchg Double redos   %lu\nUnlocked Cmpxchg Double redos %lu\n",
+                       s->cmpxchg_double_fail, s->cmpxchg_double_cpu_fail);
 }
 
 static void report(struct slabinfo *s)
@@ -573,12 +589,13 @@ static void slabcache(struct slabinfo *s)
                total_alloc = s->alloc_fastpath + s->alloc_slowpath;
                total_free = s->free_fastpath + s->free_slowpath;
 
-               printf("%-21s %8ld %10ld %10ld %3ld %3ld %5ld %1d\n",
+               printf("%-21s %8ld %10ld %10ld %3ld %3ld %5ld %1d %4ld %4ld\n",
                        s->name, s->objects,
                        total_alloc, total_free,
                        total_alloc ? (s->alloc_fastpath * 100 / total_alloc) : 0,
                        total_free ? (s->free_fastpath * 100 / total_free) : 0,
-                       s->order_fallback, s->order);
+                       s->order_fallback, s->order, s->cmpxchg_double_fail,
+                       s->cmpxchg_double_cpu_fail);
        }
        else
                printf("%-21s %8ld %7d %8s %14s %4d %1d %3ld %3ld %s\n",
@@ -1190,6 +1207,10 @@ static void read_slab_dir(void)
                        slab->deactivate_to_tail = get_obj("deactivate_to_tail");
                        slab->deactivate_remote_frees = get_obj("deactivate_remote_frees");
                        slab->order_fallback = get_obj("order_fallback");
+                       slab->cmpxchg_double_cpu_fail = get_obj("cmpxchg_double_cpu_fail");
+                       slab->cmpxchg_double_fail = get_obj("cmpxchg_double_fail");
+                       slab->alloc_node_mismatch = get_obj("alloc_node_mismatch");
+                       slab->deactivate_bypass = get_obj("deactivate_bypass");
                        chdir("..");
                        if (slab->name[0] == ':')
                                alias_targets++;