text: /*
   * 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.
   *
   * (C) 2007 SGI, Christoph Lameter
   */
  
  #include <linux/mm.h>
  #include <linux/swap.h> /* struct reclaim_state */
  #include <linux/module.h>
  #include <linux/bit_spinlock.h>
  #include <linux/interrupt.h>
  #include <linux/bitops.h>
  #include <linux/slab.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/kmemcheck.h>
  #include <linux/cpu.h>
  #include <linux/cpuset.h>
  #include <linux/mempolicy.h>
  #include <linux/ctype.h>
  #include <linux/debugobjects.h>
  #include <linux/kallsyms.h>
  #include <linux/memory.h>
  #include <linux/math64.h>
  #include <linux/fault-inject.h>
  
  #include <trace/events/kmem.h>
  
  /*
   * Lock order:
   *   1. slab_lock(page)
   *   2. slab->list_lock
   *
   *   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.
   *
   *   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
   *   removed from the lists nor make the number of partial slabs be modified.
   *   (Note that the total number of slabs is an atomic value that may be
   *   modified without taking the list lock).
   *
   *   The list_lock is a centralized lock and thus we avoid taking it as
   *   much as possible. As long as SLUB does not have to handle partial
   *   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
   *   while handling per_cpu slabs, due to kernel preemption.
   *
   * SLUB assigns one slab for allocation to each processor.
   * Allocations only occur from these slabs called cpu slabs.
   *
   * Slabs with free elements are kept on a partial list and during regular
   * operations no list for full slabs is used. If an object in a full slab is
   * freed then the slab will show up again on the partial lists.
   * We track full slabs for debugging purposes though because otherwise we
   * cannot scan all objects.
   *
   * Slabs are freed when they become empty. Teardown and setup is
   * minimal so we rely on the page allocators per cpu caches for
   * fast frees and allocs.
   *
   * Overloading of page flags that are otherwise used for LRU management.
   *
   * PageActive 		The slab is frozen and exempt from list processing.
   * 			This means that the slab is dedicated to a purpose
   * 			such as satisfying allocations for a specific
   * 			processor. Objects may be freed in the slab while
   * 			it is frozen but slab_free will then skip the usual
   * 			list operations. It is up to the processor holding
   * 			the slab to integrate the slab into the slab lists
   * 			when the slab is no longer needed.
   *
   * 			One use of this flag is to mark slabs that are
   * 			used for allocations. Then such a slab becomes a cpu
   * 			slab. The cpu slab may be equipped with an additional
   * 			freelist that allows lockless access to
   * 			free objects in addition to the regular freelist
   * 			that requires the slab lock.
   *
   * PageError		Slab requires special handling due to debug
   * 			options set. This moves	slab handling out of
   * 			the fast path and disables lockless freelists.
   */
  
  #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
  		SLAB_TRACE | SLAB_DEBUG_FREE)
  
  static inline int kmem_cache_debug(struct kmem_cache *s)
  {
  #ifdef CONFIG_SLUB_DEBUG
  	return unlikely(s->flags & SLAB_DEBUG_FLAGS);
  #else
  	return 0;
  #endif
  }
  
  /*
   * Issues still to be resolved:
   *
   * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
   *
   * - Variable sizing of the per node arrays
   */
  
  /* Enable to test recovery from slab corruption on boot */
  #undef SLUB_RESILIENCY_TEST
  
  /*
   * Mininum number of partial slabs. These will be left on the partial
   * lists even if they are empty. kmem_cache_shrink may reclaim them.
   */
  #define MIN_PARTIAL 5
  
  /*
   * Maximum number of desirable partial slabs.
   * The existence of more partial slabs makes kmem_cache_shrink
   * sort the partial list by the number of objects in the.
   */
  #define MAX_PARTIAL 10
  
  #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
  				SLAB_POISON | SLAB_STORE_USER)
  
  /*
   * Debugging flags that require metadata to be stored in the slab.  These get
   * disabled when slub_debug=O is used and a cache's min order increases with
   * metadata.
   */
  #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
  
  /*
   * Set of flags that will prevent slab merging
   */
  #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
  		SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
  		SLAB_FAILSLAB)
  
  #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
  		SLAB_CACHE_DMA | SLAB_NOTRACK)
  
  #define OO_SHIFT	16
  #define OO_MASK		((1 << OO_SHIFT) - 1)
  #define MAX_OBJS_PER_PAGE	65535 /* since page.objects is u16 */
  
  /* Internal SLUB flags */
  #define __OBJECT_POISON		0x80000000UL /* Poison object */
  
  static int kmem_size = sizeof(struct kmem_cache);
  
  #ifdef CONFIG_SMP
  static struct notifier_block slab_notifier;
  #endif
  
  static enum {
  	DOWN,		/* No slab functionality available */
  	PARTIAL,	/* Kmem_cache_node works */
  	UP,		/* Everything works but does not show up in sysfs */
  	SYSFS		/* Sysfs up */
  } slab_state = DOWN;
  
  /* A list of all slab caches on the system */
  static DECLARE_RWSEM(slub_lock);
  static LIST_HEAD(slab_caches);
  
  /*
   * Tracking user of a slab.
   */
  struct track {
  	unsigned long addr;	/* Called from address */
  	int cpu;		/* Was running on cpu */
  	int pid;		/* Pid context */
  	unsigned long when;	/* When did the operation occur */
  };
  
  enum track_item { TRACK_ALLOC, TRACK_FREE };
  
  #ifdef CONFIG_SYSFS
  static int sysfs_slab_add(struct kmem_cache *);
  static int sysfs_slab_alias(struct kmem_cache *, const char *);
  static void sysfs_slab_remove(struct kmem_cache *);
  
  #else
  static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
  static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
  							{ return 0; }
  static inline void sysfs_slab_remove(struct kmem_cache *s)
  {
  	kfree(s->name);
  	kfree(s);
  }
  
  #endif
  
  static inline void stat(const struct kmem_cache *s, enum stat_item si)
  {
  #ifdef CONFIG_SLUB_STATS
  	__this_cpu_inc(s->cpu_slab->stat[si]);
  #endif
  }
  
  /********************************************************************
   * 			Core slab cache functions
   *******************************************************************/
  
  int slab_is_available(void)
  {
  	return slab_state >= UP;
  }
  
  static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
  {
  	return s->node[node];
  }
  
  /* Verify that a pointer has an address that is valid within a slab page */
  static inline int check_valid_pointer(struct kmem_cache *s,
  				struct page *page, const void *object)
  {
  	void *base;
  
  	if (!object)
  		return 1;
  
  	base = page_address(page);
  	if (object < base || object >= base + page->objects * s->size ||
  		(object - base) % s->size) {
  		return 0;
  	}
  
  	return 1;
  }
  
  static inline void *get_freepointer(struct kmem_cache *s, void *object)
  {
  	return *(void **)(object + s->offset);
  }
  
  static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
  {
  	void *p;
  
  #ifdef CONFIG_DEBUG_PAGEALLOC
  	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
  #else
  	p = get_freepointer(s, object);
  #endif
  	return p;
  }
  
  static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
  {
  	*(void **)(object + s->offset) = fp;
  }
  
  /* Loop over all objects in a slab */
  #define for_each_object(__p, __s, __addr, __objects) \
  	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
  			__p += (__s)->size)
  
  /* Determine object index from a given position */
  static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
  {
  	return (p - addr) / s->size;
  }
  
  static inline size_t slab_ksize(const struct kmem_cache *s)
  {
  #ifdef CONFIG_SLUB_DEBUG
  	/*
  	 * Debugging requires use of the padding between object
  	 * and whatever may come after it.
  	 */
  	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
  		return s->objsize;
  
  #endif
  	/*
  	 * If we have the need to store the freelist pointer
  	 * back there or track user information then we can
  	 * only use the space before that information.
  	 */
  	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
  		return s->inuse;
  	/*
  	 * Else we can use all the padding etc for the allocation
  	 */
  	return s->size;
  }
  
  static inline int order_objects(int order, unsigned long size, int reserved)
  {
  	return ((PAGE_SIZE << order) - reserved) / size;
  }
  
  static inline struct kmem_cache_order_objects oo_make(int order,
  		unsigned long size, int reserved)
  {
  	struct kmem_cache_order_objects x = {
  		(order << OO_SHIFT) + order_objects(order, size, reserved)
  	};
  
  	return x;
  }
  
  static inline int oo_order(struct kmem_cache_order_objects x)
  {
  	return x.x >> OO_SHIFT;
  }
  
  static inline int oo_objects(struct kmem_cache_order_objects x)
  {
  	return x.x & OO_MASK;
  }
  
  #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
   * not vanish from under us.
   */
  static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
  {
  	void *p;
  	void *addr = page_address(page);
  
  	for (p = page->freelist; p; p = get_freepointer(s, p))
  		set_bit(slab_index(p, s, addr), map);
  }
  
  /*
   * Debug settings:
   */
  #ifdef CONFIG_SLUB_DEBUG_ON
  static int slub_debug = DEBUG_DEFAULT_FLAGS;
  #else
  static int slub_debug;
  #endif
  
  static char *slub_debug_slabs;
  static int disable_higher_order_debug;
  
  /*
   * Object debugging
   */
  static void print_section(char *text, u8 *addr, unsigned int length)
  {
  	int i, offset;
  	int newline = 1;
  	char ascii[17];
  
  	ascii[16] = 0;
  
  	for (i = 0; i < length; i++) {
  		if (newline) {
  			printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
  			newline = 0;
  		}
  		printk(KERN_CONT " %02x", addr[i]);
  		offset = i % 16;
  		ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
  		if (offset == 15) {
  			printk(KERN_CONT " %s\n", ascii);
  			newline = 1;
  		}
  	}
  	if (!newline) {
  		i %= 16;
  		while (i < 16) {
  			printk(KERN_CONT "   ");
  			ascii[i] = ' ';
  			i++;
  		}
  		printk(KERN_CONT " %s\n", ascii);
  	}
  }
  
  static struct track *get_track(struct kmem_cache *s, void *object,
  	enum track_item alloc)
  {
  	struct track *p;
  
  	if (s->offset)
  		p = object + s->offset + sizeof(void *);
  	else
  		p = object + s->inuse;
  
  	return p + alloc;
  }
  
  static void set_track(struct kmem_cache *s, void *object,
  			enum track_item alloc, unsigned long addr)
  {
  	struct track *p = get_track(s, object, alloc);
  
  	if (addr) {
  		p->addr = addr;
  		p->cpu = smp_processor_id();
  		p->pid = current->pid;
  		p->when = jiffies;
  	} else
  		memset(p, 0, sizeof(struct track));
  }
  
  static void init_tracking(struct kmem_cache *s, void *object)
  {
  	if (!(s->flags & SLAB_STORE_USER))
  		return;
  
  	set_track(s, object, TRACK_FREE, 0UL);
  	set_track(s, object, TRACK_ALLOC, 0UL);
  }
  
  static void print_track(const char *s, struct track *t)
  {
  	if (!t->addr)
  		return;
  
  	printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
  		s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
  }
  
  static void print_tracking(struct kmem_cache *s, void *object)
  {
  	if (!(s->flags & SLAB_STORE_USER))
  		return;
  
  	print_track("Allocated", get_track(s, object, TRACK_ALLOC));
  	print_track("Freed", get_track(s, object, TRACK_FREE));
  }
  
  static void print_page_info(struct page *page)
  {
  	printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
  		page, page->objects, page->inuse, page->freelist, page->flags);
  
  }
  
  static void slab_bug(struct kmem_cache *s, char *fmt, ...)
  {
  	va_list args;
  	char buf[100];
  
  	va_start(args, fmt);
  	vsnprintf(buf, sizeof(buf), fmt, args);
  	va_end(args);
  	printk(KERN_ERR "========================================"
  			"=====================================\n");
  	printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
  	printk(KERN_ERR "----------------------------------------"
  			"-------------------------------------\n\n");
  }
  
  static void slab_fix(struct kmem_cache *s, char *fmt, ...)
  {
  	va_list args;
  	char buf[100];
  
  	va_start(args, fmt);
  	vsnprintf(buf, sizeof(buf), fmt, args);
  	va_end(args);
  	printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
  }
  
  static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
  {
  	unsigned int off;	/* Offset of last byte */
  	u8 *addr = page_address(page);
  
  	print_tracking(s, p);
  
  	print_page_info(page);
  
  	printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
  			p, p - addr, get_freepointer(s, p));
  
  	if (p > addr + 16)
  		print_section("Bytes b4", p - 16, 16);
  
  	print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE));
  
  	if (s->flags & SLAB_RED_ZONE)
  		print_section("Redzone", p + s->objsize,
  			s->inuse - s->objsize);
  
  	if (s->offset)
  		off = s->offset + sizeof(void *);
  	else
  		off = s->inuse;
  
  	if (s->flags & SLAB_STORE_USER)
  		off += 2 * sizeof(struct track);
  
  	if (off != s->size)
  		/* Beginning of the filler is the free pointer */
  		print_section("Padding", p + off, s->size - off);
  
  	dump_stack();
  }
  
  static void object_err(struct kmem_cache *s, struct page *page,
  			u8 *object, char *reason)
  {
  	slab_bug(s, "%s", reason);
  	print_trailer(s, page, object);
  }
  
  static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
  {
  	va_list args;
  	char buf[100];
  
  	va_start(args, fmt);
  	vsnprintf(buf, sizeof(buf), fmt, args);
  	va_end(args);
  	slab_bug(s, "%s", buf);
  	print_page_info(page);
  	dump_stack();
  }
  
  static void init_object(struct kmem_cache *s, void *object, u8 val)
  {
  	u8 *p = object;
  
  	if (s->flags & __OBJECT_POISON) {
  		memset(p, POISON_FREE, s->objsize - 1);
  		p[s->objsize - 1] = POISON_END;
  	}
  
  	if (s->flags & SLAB_RED_ZONE)
  		memset(p + s->objsize, val, s->inuse - s->objsize);
  }
  
  static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
  {
  	while (bytes) {
  		if (*start != (u8)value)
  			return start;
  		start++;
  		bytes--;
  	}
  	return NULL;
  }
  
  static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
  						void *from, void *to)
  {
  	slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
  	memset(from, data, to - from);
  }
  
  static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
  			u8 *object, char *what,
  			u8 *start, unsigned int value, unsigned int bytes)
  {
  	u8 *fault;
  	u8 *end;
  
  	fault = check_bytes(start, value, bytes);
  	if (!fault)
  		return 1;
  
  	end = start + bytes;
  	while (end > fault && end[-1] == value)
  		end--;
  
  	slab_bug(s, "%s overwritten", what);
  	printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
  					fault, end - 1, fault[0], value);
  	print_trailer(s, page, object);
  
  	restore_bytes(s, what, value, fault, end);
  	return 0;
  }
  
  /*
   * Object layout:
   *
   * object address
   * 	Bytes of the object to be managed.
   * 	If the freepointer may overlay the object then the free
   * 	pointer is the first word of the object.
   *
   * 	Poisoning uses 0x6b (POISON_FREE) and the last byte is
   * 	0xa5 (POISON_END)
   *
   * object + s->objsize
   * 	Padding to reach word boundary. This is also used for Redzoning.
   * 	Padding is extended by another word if Redzoning is enabled and
   * 	objsize == inuse.
   *
   * 	We fill with 0xbb (RED_INACTIVE) for inactive objects and with
   * 	0xcc (RED_ACTIVE) for objects in use.
   *
   * object + s->inuse
   * 	Meta data starts here.
   *
   * 	A. Free pointer (if we cannot overwrite object on free)
   * 	B. Tracking data for SLAB_STORE_USER
   * 	C. Padding to reach required alignment boundary or at mininum
   * 		one word if debugging is on to be able to detect writes
   * 		before the word boundary.
   *
   *	Padding is done using 0x5a (POISON_INUSE)
   *
   * object + s->size
   * 	Nothing is used beyond s->size.
   *
   * If slabcaches are merged then the objsize and inuse boundaries are mostly
   * ignored. And therefore no slab options that rely on these boundaries
   * may be used with merged slabcaches.
   */
  
  static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
  {
  	unsigned long off = s->inuse;	/* The end of info */
  
  	if (s->offset)
  		/* Freepointer is placed after the object. */
  		off += sizeof(void *);
  
  	if (s->flags & SLAB_STORE_USER)
  		/* We also have user information there */
  		off += 2 * sizeof(struct track);
  
  	if (s->size == off)
  		return 1;
  
  	return check_bytes_and_report(s, page, p, "Object padding",
  				p + off, POISON_INUSE, s->size - off);
  }
  
  /* Check the pad bytes at the end of a slab page */
  static int slab_pad_check(struct kmem_cache *s, struct page *page)
  {
  	u8 *start;
  	u8 *fault;
  	u8 *end;
  	int length;
  	int remainder;
  
  	if (!(s->flags & SLAB_POISON))
  		return 1;
  
  	start = page_address(page);
  	length = (PAGE_SIZE << compound_order(page)) - s->reserved;
  	end = start + length;
  	remainder = length % s->size;
  	if (!remainder)
  		return 1;
  
  	fault = check_bytes(end - remainder, POISON_INUSE, remainder);
  	if (!fault)
  		return 1;
  	while (end > fault && end[-1] == POISON_INUSE)
  		end--;
  
  	slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
  	print_section("Padding", end - remainder, remainder);
  
  	restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
  	return 0;
  }
  
  static int check_object(struct kmem_cache *s, struct page *page,
  					void *object, u8 val)
  {
  	u8 *p = object;
  	u8 *endobject = object + s->objsize;
  
  	if (s->flags & SLAB_RED_ZONE) {
  		if (!check_bytes_and_report(s, page, object, "Redzone",
  			endobject, val, s->inuse - s->objsize))
  			return 0;
  	} else {
  		if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
  			check_bytes_and_report(s, page, p, "Alignment padding",
  				endobject, POISON_INUSE, s->inuse - s->objsize);
  		}
  	}
  
  	if (s->flags & SLAB_POISON) {
  		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
  			(!check_bytes_and_report(s, page, p, "Poison", p,
  					POISON_FREE, s->objsize - 1) ||
  			 !check_bytes_and_report(s, page, p, "Poison",
  				p + s->objsize - 1, POISON_END, 1)))
  			return 0;
  		/*
  		 * check_pad_bytes cleans up on its own.
  		 */
  		check_pad_bytes(s, page, p);
  	}
  
  	if (!s->offset && val == SLUB_RED_ACTIVE)
  		/*
  		 * Object and freepointer overlap. Cannot check
  		 * freepointer while object is allocated.
  		 */
  		return 1;
  
  	/* Check free pointer validity */
  	if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
  		object_err(s, page, p, "Freepointer corrupt");
  		/*
  		 * No choice but to zap it and thus lose the remainder
  		 * of the free objects in this slab. May cause
  		 * another error because the object count is now wrong.
  		 */
  		set_freepointer(s, p, NULL);
  		return 0;
  	}
  	return 1;
  }
  
  static int check_slab(struct kmem_cache *s, struct page *page)
  {
  	int maxobj;
  
  	VM_BUG_ON(!irqs_disabled());
  
  	if (!PageSlab(page)) {
  		slab_err(s, page, "Not a valid slab page");
  		return 0;
  	}
  
  	maxobj = order_objects(compound_order(page), s->size, s->reserved);
  	if (page->objects > maxobj) {
  		slab_err(s, page, "objects %u > max %u",
  			s->name, page->objects, maxobj);
  		return 0;
  	}
  	if (page->inuse > page->objects) {
  		slab_err(s, page, "inuse %u > max %u",
  			s->name, page->inuse, page->objects);
  		return 0;
  	}
  	/* Slab_pad_check fixes things up after itself */
  	slab_pad_check(s, page);
  	return 1;
  }
  
  /*
   * Determine if a certain object on a page is on the freelist. Must hold the
   * slab lock to guarantee that the chains are in a consistent state.
   */
  static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
  {
  	int nr = 0;
  	void *fp = page->freelist;
  	void *object = NULL;
  	unsigned long max_objects;
  
  	while (fp && nr <= page->objects) {
  		if (fp == search)
  			return 1;
  		if (!check_valid_pointer(s, page, fp)) {
  			if (object) {
  				object_err(s, page, object,
  					"Freechain corrupt");
  				set_freepointer(s, object, NULL);
  				break;
  			} else {
  				slab_err(s, page, "Freepointer corrupt");
  				page->freelist = NULL;
  				page->inuse = page->objects;
  				slab_fix(s, "Freelist cleared");
  				return 0;
  			}
  			break;
  		}
  		object = fp;
  		fp = get_freepointer(s, object);
  		nr++;
  	}
  
  	max_objects = order_objects(compound_order(page), s->size, s->reserved);
  	if (max_objects > MAX_OBJS_PER_PAGE)
  		max_objects = MAX_OBJS_PER_PAGE;
  
  	if (page->objects != max_objects) {
  		slab_err(s, page, "Wrong number of objects. Found %d but "
  			"should be %d", page->objects, max_objects);
  		page->objects = max_objects;
  		slab_fix(s, "Number of objects adjusted.");
  	}
  	if (page->inuse != page->objects - nr) {
  		slab_err(s, page, "Wrong object count. Counter is %d but "
  			"counted were %d", page->inuse, page->objects - nr);
  		page->inuse = page->objects - nr;
  		slab_fix(s, "Object count adjusted.");
  	}
  	return search == NULL;
  }
  
  static void trace(struct kmem_cache *s, struct page *page, void *object,
  								int alloc)
  {
  	if (s->flags & SLAB_TRACE) {
  		printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
  			s->name,
  			alloc ? "alloc" : "free",
  			object, page->inuse,
  			page->freelist);
  
  		if (!alloc)
  			print_section("Object", (void *)object, s->objsize);
  
  		dump_stack();
  	}
  }
  
  /*
   * Hooks for other subsystems that check memory allocations. In a typical
   * production configuration these hooks all should produce no code at all.
   */
  static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
  {
  	flags &= gfp_allowed_mask;
  	lockdep_trace_alloc(flags);
  	might_sleep_if(flags & __GFP_WAIT);
  
  	return should_failslab(s->objsize, flags, s->flags);
  }
  
  static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
  {
  	flags &= gfp_allowed_mask;
  	kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
  	kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
  }
  
  static inline void slab_free_hook(struct kmem_cache *s, void *x)
  {
  	kmemleak_free_recursive(x, s->flags);
  
  	/*
  	 * Trouble is that we may no longer disable interupts in the fast path
  	 * So in order to make the debug calls that expect irqs to be
  	 * disabled we need to disable interrupts temporarily.
  	 */
  #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
  	{
  		unsigned long flags;
  
  		local_irq_save(flags);
  		kmemcheck_slab_free(s, x, s->objsize);
  		debug_check_no_locks_freed(x, s->objsize);
  		local_irq_restore(flags);
  	}
  #endif
  	if (!(s->flags & SLAB_DEBUG_OBJECTS))
  		debug_check_no_obj_freed(x, s->objsize);
  }
  
  /*
   * Tracking of fully allocated slabs for debugging purposes.
   */
  static void add_full(struct kmem_cache_node *n, struct page *page)
  {
  	spin_lock(&n->list_lock);
  	list_add(&page->lru, &n->full);
  	spin_unlock(&n->list_lock);
  }
  
  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 */
  static inline unsigned long slabs_node(struct kmem_cache *s, int node)
  {
  	struct kmem_cache_node *n = get_node(s, node);
  
  	return atomic_long_read(&n->nr_slabs);
  }
  
  static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
  {
  	return atomic_long_read(&n->nr_slabs);
  }
  
  static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
  {
  	struct kmem_cache_node *n = get_node(s, node);
  
  	/*
  	 * May be called early in order to allocate a slab for the
  	 * kmem_cache_node structure. Solve the chicken-egg
  	 * dilemma by deferring the increment of the count during
  	 * bootstrap (see early_kmem_cache_node_alloc).
  	 */
  	if (n) {
  		atomic_long_inc(&n->nr_slabs);
  		atomic_long_add(objects, &n->total_objects);
  	}
  }
  static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
  {
  	struct kmem_cache_node *n = get_node(s, node);
  
  	atomic_long_dec(&n->nr_slabs);
  	atomic_long_sub(objects, &n->total_objects);
  }
  
  /* Object debug checks for alloc/free paths */
  static void setup_object_debug(struct kmem_cache *s, struct page *page,
  								void *object)
  {
  	if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
  		return;
  
  	init_object(s, object, SLUB_RED_INACTIVE);
  	init_tracking(s, object);
  }
  
  static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
  					void *object, unsigned long addr)
  {
  	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;
  	}
  
  	if (!check_object(s, page, object, SLUB_RED_INACTIVE))
  		goto bad;
  
  	/* Success perform special debug activities for allocs */
  	if (s->flags & SLAB_STORE_USER)
  		set_track(s, object, TRACK_ALLOC, addr);
  	trace(s, page, object, 1);
  	init_object(s, object, SLUB_RED_ACTIVE);
  	return 1;
  
  bad:
  	if (PageSlab(page)) {
  		/*
  		 * If this is a slab page then lets do the best we can
  		 * to avoid issues in the future. Marking all objects
  		 * as used avoids touching the remaining objects.
  		 */
  		slab_fix(s, "Marking all objects used");
  		page->inuse = page->objects;
  		page->freelist = NULL;
  	}
  	return 0;
  }
  
  static noinline int free_debug_processing(struct kmem_cache *s,
  		 struct page *page, void *object, unsigned long addr)
  {
  	if (!check_slab(s, page))
  		goto fail;
  
  	if (!check_valid_pointer(s, page, object)) {
  		slab_err(s, page, "Invalid object pointer 0x%p", object);
  		goto fail;
  	}
  
  	if (on_freelist(s, page, object)) {
  		object_err(s, page, object, "Object already free");
  		goto fail;
  	}
  
  	if (!check_object(s, page, object, SLUB_RED_ACTIVE))
  		return 0;
  
  	if (unlikely(s != page->slab)) {
  		if (!PageSlab(page)) {
  			slab_err(s, page, "Attempt to free object(0x%p) "
  				"outside of slab", object);
  		} else if (!page->slab) {
  			printk(KERN_ERR
  				"SLUB <none>: no slab for object 0x%p.\n",
  						object);
  			dump_stack();
  		} else
  			object_err(s, page, object,
  					"page slab pointer corrupt.");
  		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;
  
  fail:
  	slab_fix(s, "Object at 0x%p not freed", object);
  	return 0;
  }
  
  static int __init setup_slub_debug(char *str)
  {
  	slub_debug = DEBUG_DEFAULT_FLAGS;
  	if (*str++ != '=' || !*str)
  		/*
  		 * No options specified. Switch on full debugging.
  		 */
  		goto out;
  
  	if (*str == ',')
  		/*
  		 * No options but restriction on slabs. This means full
  		 * debugging for slabs matching a pattern.
  		 */
  		goto check_slabs;
  
  	if (tolower(*str) == 'o') {
  		/*
  		 * Avoid enabling debugging on caches if its minimum order
  		 * would increase as a result.
  		 */
  		disable_higher_order_debug = 1;
  		goto out;
  	}
  
  	slub_debug = 0;
  	if (*str == '-')
  		/*
  		 * Switch off all debugging measures.
  		 */
  		goto out;
  
  	/*
  	 * Determine which debug features should be switched on
  	 */
  	for (; *str && *str != ','; str++) {
  		switch (tolower(*str)) {
  		case 'f':
  			slub_debug |= SLAB_DEBUG_FREE;
  			break;
  		case 'z':
  			slub_debug |= SLAB_RED_ZONE;
  			break;
  		case 'p':
  			slub_debug |= SLAB_POISON;
  			break;
  		case 'u':
  			slub_debug |= SLAB_STORE_USER;
  			break;
  		case 't':
  			slub_debug |= SLAB_TRACE;
  			break;
  		case 'a':
  			slub_debug |= SLAB_FAILSLAB;
  			break;
  		default:
  			printk(KERN_ERR "slub_debug option '%c' "
  				"unknown. skipped\n", *str);
  		}
  	}
  
  check_slabs:
  	if (*str == ',')
  		slub_debug_slabs = str + 1;
  out:
  	return 1;
  }
  
  __setup("slub_debug", setup_slub_debug);
  
  static unsigned long kmem_cache_flags(unsigned long objsize,
  	unsigned long flags, const char *name,
  	void (*ctor)(void *))
  {
  	/*
  	 * Enable debugging if selected on the kernel commandline.
  	 */
  	if (slub_debug && (!slub_debug_slabs ||
  		!strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
  		flags |= slub_debug;
  
  	return flags;
  }
  #else
  static inline void setup_object_debug(struct kmem_cache *s,
  			struct page *page, void *object) {}
  
  static inline int alloc_debug_processing(struct kmem_cache *s,
  	struct page *page, void *object, unsigned long addr) { return 0; }
  
  static inline int free_debug_processing(struct kmem_cache *s,
  	struct page *page, void *object, unsigned long addr) { return 0; }
  
  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 unsigned long kmem_cache_flags(unsigned long objsize,
  	unsigned long flags, const char *name,
  	void (*ctor)(void *))
  {
  	return flags;
  }
  #define slub_debug 0
  
  #define disable_higher_order_debug 0
  
  static inline unsigned long slabs_node(struct kmem_cache *s, int node)
  							{ return 0; }
  static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
  							{ return 0; }
  static inline void inc_slabs_node(struct kmem_cache *s, int node,
  							int objects) {}
  static inline void dec_slabs_node(struct kmem_cache *s, int node,
  							int objects) {}
  
  static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
  							{ return 0; }
  
  static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
  		void *object) {}
  
  static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
  
  #endif /* CONFIG_SLUB_DEBUG */
  
  /*
   * Slab allocation and freeing
   */
  static inline struct page *alloc_slab_page(gfp_t flags, int node,
  					struct kmem_cache_order_objects oo)
  {
  	int order = oo_order(oo);
  
  	flags |= __GFP_NOTRACK;
  
  	if (node == NUMA_NO_NODE)
  		return alloc_pages(flags, order);
  	else
  		return alloc_pages_exact_node(node, flags, order);
  }
  
  static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
  {
  	struct page *page;
  	struct kmem_cache_order_objects oo = s->oo;
  	gfp_t alloc_gfp;
  
  	flags |= s->allocflags;
  
  	/*
  	 * Let the initial higher-order allocation fail under memory pressure
  	 * so we fall-back to the minimum order allocation.
  	 */
  	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
  
  	page = alloc_slab_page(alloc_gfp, node, oo);
  	if (unlikely(!page)) {
  		oo = s->min;
  		/*
  		 * Allocation may have failed due to fragmentation.
  		 * Try a lower order alloc if possible
  		 */
  		page = alloc_slab_page(flags, node, oo);
  		if (!page)
  			return NULL;
  
  		stat(s, ORDER_FALLBACK);
  	}
  
  	if (kmemcheck_enabled
  		&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
  		int pages = 1 << oo_order(oo);
  
  		kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
  
  		/*
  		 * Objects from caches that have a constructor don't get
  		 * cleared when they're allocated, so we need to do it here.
  		 */
  		if (s->ctor)
  			kmemcheck_mark_uninitialized_pages(page, pages);
  		else
  			kmemcheck_mark_unallocated_pages(page, pages);
  	}
  
  	page->objects = oo_objects(oo);
  	mod_zone_page_state(page_zone(page),
  		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
  		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
  		1 << oo_order(oo));
  
  	return page;
  }
  
  static void setup_object(struct kmem_cache *s, struct page *page,
  				void *object)
  {
  	setup_object_debug(s, page, object);
  	if (unlikely(s->ctor))
  		s->ctor(object);
  }
  
  static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
  {
  	struct page *page;
  	void *start;
  	void *last;
  	void *p;
  
  	BUG_ON(flags & GFP_SLAB_BUG_MASK);
  
  	page = allocate_slab(s,
  		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
  	if (!page)
  		goto out;
  
  	inc_slabs_node(s, page_to_nid(page), page->objects);
  	page->slab = s;
  	page->flags |= 1 << PG_slab;
  
  	start = page_address(page);
  
  	if (unlikely(s->flags & SLAB_POISON))
  		memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
  
  	last = start;
  	for_each_object(p, s, start, page->objects) {
  		setup_object(s, page, last);
  		set_freepointer(s, last, p);
  		last = p;
  	}
  	setup_object(s, page, last);
  	set_freepointer(s, last, NULL);
  
  	page->freelist = start;
  	page->inuse = 0;
  out:
  	return page;
  }
  
  static void __free_slab(struct kmem_cache *s, struct page *page)
  {
  	int order = compound_order(page);
  	int pages = 1 << order;
  
  	if (kmem_cache_debug(s)) {
  		void *p;
  
  		slab_pad_check(s, page);
  		for_each_object(p, s, page_address(page),
  						page->objects)
  			check_object(s, page, p, SLUB_RED_INACTIVE);
  	}
  
  	kmemcheck_free_shadow(page, compound_order(page));
  
  	mod_zone_page_state(page_zone(page),
  		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
  		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
  		-pages);
  
  	__ClearPageSlab(page);
  	reset_page_mapcount(page);
  	if (current->reclaim_state)
  		current->reclaim_state->reclaimed_slab += pages;
  	__free_pages(page, order);
  }
  
  #define need_reserve_slab_rcu						\
  	(sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
  
  static void rcu_free_slab(struct rcu_head *h)
  {
  	struct page *page;
  
  	if (need_reserve_slab_rcu)
  		page = virt_to_head_page(h);
  	else
  		page = container_of((struct list_head *)h, struct page, lru);
  
  	__free_slab(page->slab, page);
  }
  
  static void free_slab(struct kmem_cache *s, struct page *page)
  {
  	if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
  		struct rcu_head *head;
  
  		if (need_reserve_slab_rcu) {
  			int order = compound_order(page);
  			int offset = (PAGE_SIZE << order) - s->reserved;
  
  			VM_BUG_ON(s->reserved != sizeof(*head));
  			head = page_address(page) + offset;
  		} else {
  			/*
  			 * RCU free overloads the RCU head over the LRU
  			 */
  			head = (void *)&page->lru;
  		}
  
  		call_rcu(head, rcu_free_slab);
  	} else
  		__free_slab(s, page);
  }
  
  static void discard_slab(struct kmem_cache *s, struct page *page)
  {
  	dec_slabs_node(s, page_to_nid(page), page->objects);
  	free_slab(s, 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
   */
  static 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,
  					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.
   *
   * Must hold list_lock.
   */
  static inline int lock_and_freeze_slab(struct kmem_cache_node *n,
  							struct page *page)
  {
  	if (slab_trylock(page)) {
  		__remove_partial(n, page);
  		__SetPageSlubFrozen(page);
  		return 1;
  	}
  	return 0;
  }
  
  /*
   * Try to allocate a partial slab from a specific node.
   */
  static struct page *get_partial_node(struct kmem_cache_node *n)
  {
  	struct page *page;
  
  	/*
  	 * Racy check. If we mistakenly see no partial slabs then we
  	 * just allocate an empty slab. If we mistakenly try to get a
  	 * partial slab and there is none available then get_partials()
  	 * will return NULL.
  	 */
  	if (!n || !n->nr_partial)
  		return NULL;
  
  	spin_lock(&n->list_lock);
  	list_for_each_entry(page, &n->partial, lru)
  		if (lock_and_freeze_slab(n, page))
  			goto out;
  	page = NULL;
  out:
  	spin_unlock(&n->list_lock);
  	return page;
  }
  
  /*
   * Get a page from somewhere. Search in increasing NUMA distances.
   */
  static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
  {
  #ifdef CONFIG_NUMA
  	struct zonelist *zonelist;
  	struct zoneref *z;
  	struct zone *zone;
  	enum zone_type high_zoneidx = gfp_zone(flags);
  	struct page *page;
  	unsigned int cpuset_mems_cookie;
  
  	/*
  	 * The defrag ratio allows a configuration of the tradeoffs between
  	 * inter node defragmentation and node local allocations. A lower
  	 * defrag_ratio increases the tendency to do local allocations
  	 * instead of attempting to obtain partial slabs from other nodes.
  	 *
  	 * If the defrag_ratio is set to 0 then kmalloc() always
  	 * returns node local objects. If the ratio is higher then kmalloc()
  	 * may return off node objects because partial slabs are obtained
  	 * from other nodes and filled up.
  	 *
  	 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
  	 * defrag_ratio = 1000) then every (well almost) allocation will
  	 * first attempt to defrag slab caches on other nodes. This means
  	 * scanning over all nodes to look for partial slabs which may be
  	 * expensive if we do it every time we are trying to find a slab
  	 * with available objects.
  	 */
  	if (!s->remote_node_defrag_ratio ||
  			get_cycles() % 1024 > s->remote_node_defrag_ratio)
  		return NULL;
  
  	do {
  		cpuset_mems_cookie = get_mems_allowed();
  		zonelist = node_zonelist(slab_node(current->mempolicy), flags);
  		for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
  			struct kmem_cache_node *n;
  
  			n = get_node(s, zone_to_nid(zone));
  
  			if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
  					n->nr_partial > s->min_partial) {
  				page = get_partial_node(n);
  				if (page) {
  					/*
  					 * Return the object even if
  					 * put_mems_allowed indicated that
  					 * the cpuset mems_allowed was
  					 * updated in parallel. It's a
  					 * harmless race between the alloc
  					 * and the cpuset update.
  					 */
  					put_mems_allowed(cpuset_mems_cookie);
  					return page;
  				}
  			}
  		}
  	} while (!put_mems_allowed(cpuset_mems_cookie));
  #endif
  	return NULL;
  }
  
  /*
   * Get a partial page, lock it and return it.
   */
  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));
  	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
   * during cmpxchg. The transactions start with the cpu number and are then
   * incremented by CONFIG_NR_CPUS.
   */
  #define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
  #else
  /*
   * No preemption supported therefore also no need to check for
   * different cpus.
   */
  #define TID_STEP 1
  #endif
  
  static inline unsigned long next_tid(unsigned long tid)
  {
  	return tid + TID_STEP;
  }
  
  static inline unsigned int tid_to_cpu(unsigned long tid)
  {
  	return tid % TID_STEP;
  }
  
  static inline unsigned long tid_to_event(unsigned long tid)
  {
  	return tid / TID_STEP;
  }
  
  static inline unsigned int init_tid(int cpu)
  {
  	return cpu;
  }
  
  static inline void note_cmpxchg_failure(const char *n,
  		const struct kmem_cache *s, unsigned long tid)
  {
  #ifdef SLUB_DEBUG_CMPXCHG
  	unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
  
  	printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
  
  #ifdef CONFIG_PREEMPT
  	if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
  		printk("due to cpu change %d -> %d\n",
  			tid_to_cpu(tid), tid_to_cpu(actual_tid));
  	else
  #endif
  	if (tid_to_event(tid) != tid_to_event(actual_tid))
  		printk("due to cpu running other code. Event %ld->%ld\n",
  			tid_to_event(tid), tid_to_event(actual_tid));
  	else
  		printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
  			actual_tid, tid, next_tid(tid));
  #endif
  	stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
  }
  
  void init_kmem_cache_cpus(struct kmem_cache *s)
  {
  	int cpu;
  
  	for_each_possible_cpu(cpu)
  		per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
  }
  /*
   * Remove the cpu slab
   */
  static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
  	__releases(bitlock)
  {
  	struct page *page = c->page;
  	int tail = 1;
  
  	if (page->freelist)
  		stat(s, DEACTIVATE_REMOTE_FREES);
  	/*
  	 * Merge cpu freelist into slab freelist. Typically we get here
  	 * because both freelists are empty. So this is unlikely
  	 * to occur.
  	 */
  	while (unlikely(c->freelist)) {
  		void **object;
  
  		tail = 0;	/* Hot objects. Put the slab first */
  
  		/* Retrieve object from cpu_freelist */
  		object = c->freelist;
  		c->freelist = get_freepointer(s, c->freelist);
  
  		/* And put onto the regular freelist */
  		set_freepointer(s, object, page->freelist);
  		page->freelist = object;
  		page->inuse--;
  	}
  	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);
  }
  
  /*
   * Flush cpu slab.
   *
   * Called from IPI handler with interrupts disabled.
   */
  static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
  {
  	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
  
  	if (likely(c && c->page))
  		flush_slab(s, c);
  }
  
  static void flush_cpu_slab(void *d)
  {
  	struct kmem_cache *s = d;
  
  	__flush_cpu_slab(s, smp_processor_id());
  }
  
  static void flush_all(struct kmem_cache *s)
  {
  	on_each_cpu(flush_cpu_slab, s, 1);
  }
  
  /*
   * Check if the objects in a per cpu structure fit numa
   * locality expectations.
   */
  static inline int node_match(struct kmem_cache_cpu *c, int node)
  {
  #ifdef CONFIG_NUMA
  	if (node != NUMA_NO_NODE && c->node != node)
  		return 0;
  #endif
  	return 1;
  }
  
  static int count_free(struct page *page)
  {
  	return page->objects - page->inuse;
  }
  
  static unsigned long count_partial(struct kmem_cache_node *n,
  					int (*get_count)(struct page *))
  {
  	unsigned long flags;
  	unsigned long x = 0;
  	struct page *page;
  
  	spin_lock_irqsave(&n->list_lock, flags);
  	list_for_each_entry(page, &n->partial, lru)
  		x += get_count(page);
  	spin_unlock_irqrestore(&n->list_lock, flags);
  	return x;
  }
  
  static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
  {
  #ifdef CONFIG_SLUB_DEBUG
  	return atomic_long_read(&n->total_objects);
  #else
  	return 0;
  #endif
  }
  
  static noinline void
  slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
  {
  	int node;
  
  	printk(KERN_WARNING
  		"SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
  		nid, gfpflags);
  	printk(KERN_WARNING "  cache: %s, object size: %d, buffer size: %d, "
  		"default order: %d, min order: %d\n", s->name, s->objsize,
  		s->size, oo_order(s->oo), oo_order(s->min));
  
  	if (oo_order(s->min) > get_order(s->objsize))
  		printk(KERN_WARNING "  %s debugging increased min order, use "
  		       "slub_debug=O to disable.\n", s->name);
  
  	for_each_online_node(node) {
  		struct kmem_cache_node *n = get_node(s, node);
  		unsigned long nr_slabs;
  		unsigned long nr_objs;
  		unsigned long nr_free;
  
  		if (!n)
  			continue;
  
  		nr_free  = count_partial(n, count_free);
  		nr_slabs = node_nr_slabs(n);
  		nr_objs  = node_nr_objs(n);
  
  		printk(KERN_WARNING
  			"  node %d: slabs: %ld, objs: %ld, free: %ld\n",
  			node, nr_slabs, nr_objs, nr_free);
  	}
  }
  
  /*
   * Slow path. The lockless freelist is empty or we need to perform
   * debugging duties.
   *
   * Interrupts are disabled.
   *
   * Processing is still very fast if new objects have been freed to the
   * regular freelist. In that case we simply take over the regular freelist
   * as the lockless freelist and zap the regular freelist.
   *
   * If that is not working then we fall back to the partial lists. We take the
   * first element of the freelist as the object to allocate now and move the
   * rest of the freelist to the lockless freelist.
   *
   * And if we were unable to get a new slab from the partial slab lists then
   * we need to allocate a new slab. This is the slowest path since it involves
   * a call to the page allocator and the setup of a new slab.
   */
  static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
  			  unsigned long addr, struct kmem_cache_cpu *c)
  {
  	void **object;
  	struct page *page;
  	unsigned long flags;
  
  	local_irq_save(flags);
  #ifdef CONFIG_PREEMPT
  	/*
  	 * We may have been preempted and rescheduled on a different
  	 * cpu before disabling interrupts. Need to reload cpu area
  	 * pointer.
  	 */
  	c = this_cpu_ptr(s->cpu_slab);
  #endif
  
  	/* We handle __GFP_ZERO in the caller */
  	gfpflags &= ~__GFP_ZERO;
  
  	page = c->page;
  	if (!page)
  		goto new_slab;
  
  	slab_lock(page);
  	if (unlikely(!node_match(c, node)))
  		goto another_slab;
  
  	/* must check again c->freelist in case of cpu migration or IRQ */
  	object = c->freelist;
  	if (object)
  		goto update_freelist;
  
  	stat(s, ALLOC_REFILL);
  
  load_freelist:
  	object = page->freelist;
  	if (unlikely(!object))
  		goto another_slab;
  	if (kmem_cache_debug(s))
  		goto debug;
  
  update_freelist:
  	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;
  		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);
  		c->node = page_to_nid(page);
  		c->page = page;
  		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;
  
  	page->inuse++;
  	page->freelist = get_freepointer(s, object);
  	deactivate_slab(s, c);
  	c->page = NULL;
  	c->node = NUMA_NO_NODE;
  	local_irq_restore(flags);
  	return object;
  }
  
  /*
   * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
   * have the fastpath folded into their functions. So no function call
   * overhead for requests that can be satisfied on the fastpath.
   *
   * The fastpath works by first checking if the lockless freelist can be used.
   * If not then __slab_alloc is called for slow processing.
   *
   * Otherwise we can simply pick the next object from the lockless free list.
   */
  static __always_inline void *slab_alloc(struct kmem_cache *s,
  		gfp_t gfpflags, int node, unsigned long addr)
  {
  	void **object;
  	struct kmem_cache_cpu *c;
  	unsigned long tid;
  
  	if (slab_pre_alloc_hook(s, gfpflags))
  		return NULL;
  
  redo:
  
  	/*
  	 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
  	 * enabled. We may switch back and forth between cpus while
  	 * reading from one cpu area. That does not matter as long
  	 * as we end up on the original cpu again when doing the cmpxchg.
  	 */
  	c = __this_cpu_ptr(s->cpu_slab);
  
  	/*
  	 * The transaction ids are globally unique per cpu and per operation on
  	 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
  	 * occurs on the right processor and that there was no operation on the
  	 * linked list in between.
  	 */
  	tid = c->tid;
  	barrier();
  
  	object = c->freelist;
  	if (unlikely(!object || !node_match(c, node)))
  
  		object = __slab_alloc(s, gfpflags, node, addr, c);
  
  	else {
  		/*
  		 * The cmpxchg will only match if there was no additional
  		 * operation and if we are on the right processor.
  		 *
  		 * The cmpxchg does the following atomically (without lock semantics!)
  		 * 1. Relocate first pointer to the current per cpu area.
  		 * 2. Verify that tid and freelist have not been changed
  		 * 3. If they were not changed replace tid and freelist
  		 *
  		 * Since this is without lock semantics the protection is only against
  		 * code executing on this cpu *not* from access by other cpus.
  		 */
  		if (unlikely(!irqsafe_cpu_cmpxchg_double(
  				s->cpu_slab->freelist, s->cpu_slab->tid,
  				object, tid,
  				get_freepointer_safe(s, object), next_tid(tid)))) {
  
  			note_cmpxchg_failure("slab_alloc", s, tid);
  			goto redo;
  		}
  		stat(s, ALLOC_FASTPATH);
  	}
  
  	if (unlikely(gfpflags & __GFP_ZERO) && object)
  		memset(object, 0, s->objsize);
  
  	slab_post_alloc_hook(s, gfpflags, object);
  
  	return object;
  }
  
  void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
  {
  	void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
  
  	trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
  
  	return ret;
  }
  EXPORT_SYMBOL(kmem_cache_alloc);
  
  #ifdef CONFIG_TRACING
  void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
  {
  	void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
  	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
  	return ret;
  }
  EXPORT_SYMBOL(kmem_cache_alloc_trace);
  
  void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
  {
  	void *ret = kmalloc_order(size, flags, order);
  	trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
  	return ret;
  }
  EXPORT_SYMBOL(kmalloc_order_trace);
  #endif
  
  #ifdef CONFIG_NUMA
  void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
  {
  	void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
  
  	trace_kmem_cache_alloc_node(_RET_IP_, ret,
  				    s->objsize, s->size, gfpflags, node);
  
  	return ret;
  }
  EXPORT_SYMBOL(kmem_cache_alloc_node);
  
  #ifdef CONFIG_TRACING
  void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
  				    gfp_t gfpflags,
  				    int node, size_t size)
  {
  	void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
  
  	trace_kmalloc_node(_RET_IP_, ret,
  			   size, s->size, gfpflags, node);
  	return ret;
  }
  EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
  #endif
  #endif
  
  /*
   * Slow patch handling. This may still be called frequently since objects
   * have a longer lifetime than the cpu slabs in most processing loads.
   *
   * So we still attempt to reduce cache line usage. Just take the slab
   * lock and free the item. If there is no additional partial page
   * handling required then we can return immediately.
   */
  static void __slab_free(struct kmem_cache *s, struct page *page,
  			void *x, unsigned long addr)
  {
  	void *prior;
  	void **object = (void *)x;
  	unsigned long 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;
  
  	prior = page->freelist;
  	set_freepointer(s, object, prior);
  	page->freelist = object;
  	page->inuse--;
  
  	if (unlikely(PageSlubFrozen(page))) {
  		stat(s, FREE_FROZEN);
  		goto out_unlock;
  	}
  
  	if (unlikely(!page->inuse))
  		goto slab_empty;
  
  	/*
  	 * Objects left in the slab. If it was not on the partial list before
  	 * then add it.
  	 */
  	if (unlikely(!prior)) {
  		add_partial(get_node(s, page_to_nid(page)), page, 1);
  		stat(s, FREE_ADD_PARTIAL);
  	}
  
  out_unlock:
  	slab_unlock(page);
  	local_irq_restore(flags);
  	return;
  
  slab_empty:
  	if (prior) {
  		/*
  		 * Slab still on the partial list.
  		 */
  		remove_partial(s, page);
  		stat(s, FREE_REMOVE_PARTIAL);
  	}
  	slab_unlock(page);
  	local_irq_restore(flags);
  	stat(s, FREE_SLAB);
  	discard_slab(s, page);
  }
  
  /*
   * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
   * can perform fastpath freeing without additional function calls.
   *
   * The fastpath is only possible if we are freeing to the current cpu slab
   * of this processor. This typically the case if we have just allocated
   * the item before.
   *
   * If fastpath is not possible then fall back to __slab_free where we deal
   * with all sorts of special processing.
   */
  static __always_inline void slab_free(struct kmem_cache *s,
  			struct page *page, void *x, unsigned long addr)
  {
  	void **object = (void *)x;
  	struct kmem_cache_cpu *c;
  	unsigned long tid;
  
  	slab_free_hook(s, x);
  
  redo:
  
  	/*
  	 * Determine the currently cpus per cpu slab.
  	 * The cpu may change afterward. However that does not matter since
  	 * data is retrieved via this pointer. If we are on the same cpu
  	 * during the cmpxchg then the free will succedd.
  	 */
  	c = __this_cpu_ptr(s->cpu_slab);
  
  	tid = c->tid;
  	barrier();
  
  	if (likely(page == c->page)) {
  		set_freepointer(s, object, c->freelist);
  
  		if (unlikely(!irqsafe_cpu_cmpxchg_double(
  				s->cpu_slab->freelist, s->cpu_slab->tid,
  				c->freelist, tid,
  				object, next_tid(tid)))) {
  
  			note_cmpxchg_failure("slab_free", s, tid);
  			goto redo;
  		}
  		stat(s, FREE_FASTPATH);
  	} else
  		__slab_free(s, page, x, addr);
  
  }
  
  void kmem_cache_free(struct kmem_cache *s, void *x)
  {
  	struct page *page;
  
  	page = virt_to_head_page(x);
  
  	slab_free(s, page, x, _RET_IP_);
  
  	trace_kmem_cache_free(_RET_IP_, x);
  }
  EXPORT_SYMBOL(kmem_cache_free);
  
  /*
   * Object placement in a slab is made very easy because we always start at
   * offset 0. If we tune the size of the object to the alignment then we can
   * get the required alignment by putting one properly sized object after
   * another.
   *
   * Notice that the allocation order determines the sizes of the per cpu
   * caches. Each processor has always one slab available for allocations.
   * Increasing the allocation order reduces the number of times that slabs
   * must be moved on and off the partial lists and is therefore a factor in
   * locking overhead.
   */
  
  /*
   * Mininum / Maximum order of slab pages. This influences locking overhead
   * and slab fragmentation. A higher order reduces the number of partial slabs
   * and increases the number of allocations possible without having to
   * take the list_lock.
   */
  static int slub_min_order;
  static int slub_max_order;
  static int slub_min_objects;
  
  /*
   * Merge control. If this is set then no merging of slab caches will occur.
   * (Could be removed. This was introduced to pacify the merge skeptics.)
   */
  static int slub_nomerge;
  
  /*
   * Calculate the order of allocation given an slab object size.
   *
   * The order of allocation has significant impact on performance and other
   * system components. Generally order 0 allocations should be preferred since
   * order 0 does not cause fragmentation in the page allocator. Larger objects
   * be problematic to put into order 0 slabs because there may be too much
   * unused space left. We go to a higher order if more than 1/16th of the slab
   * would be wasted.
   *
   * In order to reach satisfactory performance we must ensure that a minimum
   * number of objects is in one slab. Otherwise we may generate too much
   * activity on the partial lists which requires taking the list_lock. This is
   * less a concern for large slabs though which are rarely used.
   *
   * slub_max_order specifies the order where we begin to stop considering the
   * number of objects in a slab as critical. If we reach slub_max_order then
   * we try to keep the page order as low as possible. So we accept more waste
   * of space in favor of a small page order.
   *
   * Higher order allocations also allow the placement of more objects in a
   * slab and thereby reduce object handling overhead. If the user has
   * requested a higher mininum order then we start with that one instead of
   * the smallest order which will fit the object.
   */
  static inline int slab_order(int size, int min_objects,
  				int max_order, int fract_leftover, int reserved)
  {
  	int order;
  	int rem;
  	int min_order = slub_min_order;
  
  	if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
  		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
  
  	for (order = max(min_order,
  				fls(min_objects * size - 1) - PAGE_SHIFT);
  			order <= max_order; order++) {
  
  		unsigned long slab_size = PAGE_SIZE << order;
  
  		if (slab_size < min_objects * size + reserved)
  			continue;
  
  		rem = (slab_size - reserved) % size;
  
  		if (rem <= slab_size / fract_leftover)
  			break;
  
  	}
  
  	return order;
  }
  
  static inline int calculate_order(int size, int reserved)
  {
  	int order;
  	int min_objects;
  	int fraction;
  	int max_objects;
  
  	/*
  	 * Attempt to find best configuration for a slab. This
  	 * works by first attempting to generate a layout with
  	 * the best configuration and backing off gradually.
  	 *
  	 * First we reduce the acceptable waste in a slab. Then
  	 * we reduce the minimum objects required in a slab.
  	 */
  	min_objects = slub_min_objects;
  	if (!min_objects)
  		min_objects = 4 * (fls(nr_cpu_ids) + 1);
  	max_objects = order_objects(slub_max_order, size, reserved);
  	min_objects = min(min_objects, max_objects);
  
  	while (min_objects > 1) {
  		fraction = 16;
  		while (fraction >= 4) {
  			order = slab_order(size, min_objects,
  					slub_max_order, fraction, reserved);
  			if (order <= slub_max_order)
  				return order;
  			fraction /= 2;
  		}
  		min_objects--;
  	}
  
  	/*
  	 * We were unable to place multiple objects in a slab. Now
  	 * lets see if we can place a single object there.
  	 */
  	order = slab_order(size, 1, slub_max_order, 1, reserved);
  	if (order <= slub_max_order)
  		return order;
  
  	/*
  	 * Doh this slab cannot be placed using slub_max_order.
  	 */
  	order = slab_order(size, 1, MAX_ORDER, 1, reserved);
  	if (order < MAX_ORDER)
  		return order;
  	return -ENOSYS;
  }
  
  /*
   * Figure out what the alignment of the objects will be.
   */
  static unsigned long calculate_alignment(unsigned long flags,
  		unsigned long align, unsigned long size)
  {
  	/*
  	 * If the user wants hardware cache aligned objects then follow that
  	 * suggestion if the object is sufficiently large.
  	 *
  	 * The hardware cache alignment cannot override the specified
  	 * alignment though. If that is greater then use it.
  	 */
  	if (flags & SLAB_HWCACHE_ALIGN) {
  		unsigned long ralign = cache_line_size();
  		while (size <= ralign / 2)
  			ralign /= 2;
  		align = max(align, ralign);
  	}
  
  	if (align < ARCH_SLAB_MINALIGN)
  		align = ARCH_SLAB_MINALIGN;
  
  	return ALIGN(align, sizeof(void *));
  }
  
  static void
  init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
  {
  	n->nr_partial = 0;
  	spin_lock_init(&n->list_lock);
  	INIT_LIST_HEAD(&n->partial);
  #ifdef CONFIG_SLUB_DEBUG
  	atomic_long_set(&n->nr_slabs, 0);
  	atomic_long_set(&n->total_objects, 0);
  	INIT_LIST_HEAD(&n->full);
  #endif
  }
  
  static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
  {
  	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
  			SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
  
  	/*
  	 * Must align to double word boundary for the double cmpxchg
  	 * instructions to work; see __pcpu_double_call_return_bool().
  	 */
  	s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
  				     2 * sizeof(void *));
  
  	if (!s->cpu_slab)
  		return 0;
  
  	init_kmem_cache_cpus(s);
  
  	return 1;
  }
  
  static struct kmem_cache *kmem_cache_node;
  
  /*
   * No kmalloc_node yet so do it by hand. We know that this is the first
   * slab on the node for this slabcache. There are no concurrent accesses
   * possible.
   *
   * Note that this function only works on the kmalloc_node_cache
   * when allocating for the kmalloc_node_cache. This is used for bootstrapping
   * memory on a fresh node that has no slab structures yet.
   */
  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));
  
  	page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
  
  	BUG_ON(!page);
  	if (page_to_nid(page) != node) {
  		printk(KERN_ERR "SLUB: Unable to allocate memory from "
  				"node %d\n", node);
  		printk(KERN_ERR "SLUB: Allocating a useless per node structure "
  				"in order to be able to continue\n");
  	}
  
  	n = page->freelist;
  	BUG_ON(!n);
  	page->freelist = get_freepointer(kmem_cache_node, n);
  	page->inuse++;
  	kmem_cache_node->node[node] = n;
  #ifdef CONFIG_SLUB_DEBUG
  	init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
  	init_tracking(kmem_cache_node, n);
  #endif
  	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)
  {
  	int node;
  
  	for_each_node_state(node, N_NORMAL_MEMORY) {
  		struct kmem_cache_node *n = s->node[node];
  
  		if (n)
  			kmem_cache_free(kmem_cache_node, n);
  
  		s->node[node] = NULL;
  	}
  }
  
  static int init_kmem_cache_nodes(struct kmem_cache *s)
  {
  	int node;
  
  	for_each_node_state(node, N_NORMAL_MEMORY) {
  		struct kmem_cache_node *n;
  
  		if (slab_state == DOWN) {
  			early_kmem_cache_node_alloc(node);
  			continue;
  		}
  		n = kmem_cache_alloc_node(kmem_cache_node,
  						GFP_KERNEL, node);
  
  		if (!n) {
  			free_kmem_cache_nodes(s);
  			return 0;
  		}
  
  		s->node[node] = n;
  		init_kmem_cache_node(n, s);
  	}
  	return 1;
  }
  
  static void set_min_partial(struct kmem_cache *s, unsigned long min)
  {
  	if (min < MIN_PARTIAL)
  		min = MIN_PARTIAL;
  	else if (min > MAX_PARTIAL)
  		min = MAX_PARTIAL;
  	s->min_partial = min;
  }
  
  /*
   * calculate_sizes() determines the order and the distribution of data within
   * a slab object.
   */
  static int calculate_sizes(struct kmem_cache *s, int forced_order)
  {
  	unsigned long flags = s->flags;
  	unsigned long size = s->objsize;
  	unsigned long align = s->align;
  	int order;
  
  	/*
  	 * Round up object size to the next word boundary. We can only
  	 * place the free pointer at word boundaries and this determines
  	 * the possible location of the free pointer.
  	 */
  	size = ALIGN(size, sizeof(void *));
  
  #ifdef CONFIG_SLUB_DEBUG
  	/*
  	 * Determine if we can poison the object itself. If the user of
  	 * the slab may touch the object after free or before allocation
  	 * then we should never poison the object itself.
  	 */
  	if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
  			!s->ctor)
  		s->flags |= __OBJECT_POISON;
  	else
  		s->flags &= ~__OBJECT_POISON;
  
  	/*
  	 * If we are Redzoning then check if there is some space between the
  	 * end of the object and the free pointer. If not then add an
  	 * additional word to have some bytes to store Redzone information.
  	 */
  	if ((flags & SLAB_RED_ZONE) && size == s->objsize)
  		size += sizeof(void *);
  #endif
  
  	/*
  	 * With that we have determined the number of bytes in actual use
  	 * by the object. This is the potential offset to the free pointer.
  	 */
  	s->inuse = size;
  
  	if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
  		s->ctor)) {
  		/*
  		 * Relocate free pointer after the object if it is not
  		 * permitted to overwrite the first word of the object on
  		 * kmem_cache_free.
  		 *
  		 * This is the case if we do RCU, have a constructor or
  		 * destructor or are poisoning the objects.
  		 */
  		s->offset = size;
  		size += sizeof(void *);
  	}
  
  #ifdef CONFIG_SLUB_DEBUG
  	if (flags & SLAB_STORE_USER)
  		/*
  		 * Need to store information about allocs and frees after
  		 * the object.
  		 */
  		size += 2 * sizeof(struct track);
  
  	if (flags & SLAB_RED_ZONE)
  		/*
  		 * Add some empty padding so that we can catch
  		 * overwrites from earlier objects rather than let
  		 * tracking information or the free pointer be
  		 * corrupted if a user writes before the start
  		 * of the object.
  		 */
  		size += sizeof(void *);
  #endif
  
  	/*
  	 * Determine the alignment based on various parameters that the
  	 * user specified and the dynamic determination of cache line size
  	 * on bootup.
  	 */
  	align = calculate_alignment(flags, align, s->objsize);
  	s->align = align;
  
  	/*
  	 * SLUB stores one object immediately after another beginning from
  	 * offset 0. In order to align the objects we have to simply size
  	 * each object to conform to the alignment.
  	 */
  	size = ALIGN(size, align);
  	s->size = size;
  	if (forced_order >= 0)
  		order = forced_order;
  	else
  		order = calculate_order(size, s->reserved);
  
  	if (order < 0)
  		return 0;
  
  	s->allocflags = 0;
  	if (order)
  		s->allocflags |= __GFP_COMP;
  
  	if (s->flags & SLAB_CACHE_DMA)
  		s->allocflags |= SLUB_DMA;
  
  	if (s->flags & SLAB_RECLAIM_ACCOUNT)
  		s->allocflags |= __GFP_RECLAIMABLE;
  
  	/*
  	 * Determine the number of objects per slab
  	 */
  	s->oo = oo_make(order, size, s->reserved);
  	s->min = oo_make(get_order(size), size, s->reserved);
  	if (oo_objects(s->oo) > oo_objects(s->max))
  		s->max = s->oo;
  
  	return !!oo_objects(s->oo);
  
  }
  
  static int kmem_cache_open(struct kmem_cache *s,
  		const char *name, size_t size,
  		size_t align, unsigned long flags,
  		void (*ctor)(void *))
  {
  	memset(s, 0, kmem_size);
  	s->name = name;
  	s->ctor = ctor;
  	s->objsize = size;
  	s->align = align;
  	s->flags = kmem_cache_flags(size, flags, name, ctor);
  	s->reserved = 0;
  
  	if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
  		s->reserved = sizeof(struct rcu_head);
  
  	if (!calculate_sizes(s, -1))
  		goto error;
  	if (disable_higher_order_debug) {
  		/*
  		 * Disable debugging flags that store metadata if the min slab
  		 * order increased.
  		 */
  		if (get_order(s->size) > get_order(s->objsize)) {
  			s->flags &= ~DEBUG_METADATA_FLAGS;
  			s->offset = 0;
  			if (!calculate_sizes(s, -1))
  				goto error;
  		}
  	}
  
  	/*
  	 * The larger the object size is, the more pages we want on the partial
  	 * list to avoid pounding the page allocator excessively.
  	 */
  	set_min_partial(s, ilog2(s->size));
  	s->refcount = 1;
  #ifdef CONFIG_NUMA
  	s->remote_node_defrag_ratio = 1000;
  #endif
  	if (!init_kmem_cache_nodes(s))
  		goto error;
  
  	if (alloc_kmem_cache_cpus(s))
  		return 1;
  
  	free_kmem_cache_nodes(s);
  error:
  	if (flags & SLAB_PANIC)
  		panic("Cannot create slab %s size=%lu realsize=%u "
  			"order=%u offset=%u flags=%lx\n",
  			s->name, (unsigned long)size, s->size, oo_order(s->oo),
  			s->offset, flags);
  	return 0;
  }
  
  /*
   * Determine the size of a slab object
   */
  unsigned int kmem_cache_size(struct kmem_cache *s)
  {
  	return s->objsize;
  }
  EXPORT_SYMBOL(kmem_cache_size);
  
  static void list_slab_objects(struct kmem_cache *s, struct page *page,
  							const char *text)
  {
  #ifdef CONFIG_SLUB_DEBUG
  	void *addr = page_address(page);
  	void *p;
  	unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
  				     sizeof(long), GFP_ATOMIC);
  	if (!map)
  		return;
  	slab_err(s, page, "%s", text);
  	slab_lock(page);
  
  	get_map(s, page, map);
  	for_each_object(p, s, addr, page->objects) {
  
  		if (!test_bit(slab_index(p, s, addr), map)) {
  			printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
  							p, p - addr);
  			print_tracking(s, p);
  		}
  	}
  	slab_unlock(page);
  	kfree(map);
  #endif
  }
  
  /*
   * Attempt to free all partial slabs on a node.
   */
  static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
  {
  	unsigned long flags;
  	struct page *page, *h;
  
  	spin_lock_irqsave(&n->list_lock, flags);
  	list_for_each_entry_safe(page, h, &n->partial, lru) {
  		if (!page->inuse) {
  			__remove_partial(n, page);
  			discard_slab(s, page);
  		} else {
  			list_slab_objects(s, page,
  				"Objects remaining on kmem_cache_close()");
  		}
  	}
  	spin_unlock_irqrestore(&n->list_lock, flags);
  }
  
  /*
   * Release all resources used by a slab cache.
   */
  static inline int kmem_cache_close(struct kmem_cache *s)
  {
  	int node;
  
  	flush_all(s);
  	free_percpu(s->cpu_slab);
  	/* Attempt to free all objects */
  	for_each_node_state(node, N_NORMAL_MEMORY) {
  		struct kmem_cache_node *n = get_node(s, node);
  
  		free_partial(s, n);
  		if (n->nr_partial || slabs_node(s, node))
  			return 1;
  	}
  	free_kmem_cache_nodes(s);
  	return 0;
  }
  
  /*
   * Close a cache and release the kmem_cache structure
   * (must be used for caches created using kmem_cache_create)
   */
  void kmem_cache_destroy(struct kmem_cache *s)
  {
  	down_write(&slub_lock);
  	s->refcount--;
  	if (!s->refcount) {
  		list_del(&s->list);
  		if (kmem_cache_close(s)) {
  			printk(KERN_ERR "SLUB %s: %s called for cache that "
  				"still has objects.\n", s->name, __func__);
  			dump_stack();
  		}
  		if (s->flags & SLAB_DESTROY_BY_RCU)
  			rcu_barrier();
  		sysfs_slab_remove(s);
  	}
  	up_write(&slub_lock);
  }
  EXPORT_SYMBOL(kmem_cache_destroy);
  
  /********************************************************************
   *		Kmalloc subsystem
   *******************************************************************/
  
  struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
  EXPORT_SYMBOL(kmalloc_caches);
  
  static struct kmem_cache *kmem_cache;
  
  #ifdef CONFIG_ZONE_DMA
  static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
  #endif
  
  static int __init setup_slub_min_order(char *str)
  {
  	get_option(&str, &slub_min_order);
  
  	return 1;
  }
  
  __setup("slub_min_order=", setup_slub_min_order);
  
  static int __init setup_slub_max_order(char *str)
  {
  	get_option(&str, &slub_max_order);
  	slub_max_order = min(slub_max_order, MAX_ORDER - 1);
  
  	return 1;
  }
  
  __setup("slub_max_order=", setup_slub_max_order);
  
  static int __init setup_slub_min_objects(char *str)
  {
  	get_option(&str, &slub_min_objects);
  
  	return 1;
  }
  
  __setup("slub_min_objects=", setup_slub_min_objects);
  
  static int __init setup_slub_nomerge(char *str)
  {
  	slub_nomerge = 1;
  	return 1;
  }
  
  __setup("slub_nomerge", setup_slub_nomerge);
  
  static struct kmem_cache *__init create_kmalloc_cache(const char *name,
  						int size, unsigned int flags)
  {
  	struct kmem_cache *s;
  
  	s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
  
  	/*
  	 * This function is called with IRQs disabled during early-boot on
  	 * single CPU so there's no need to take slub_lock here.
  	 */
  	if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
  								flags, NULL))
  		goto panic;
  
  	list_add(&s->list, &slab_caches);
  	return s;
  
  panic:
  	panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
  	return NULL;
  }
  
  /*
   * Conversion table for small slabs sizes / 8 to the index in the
   * kmalloc array. This is necessary for slabs < 192 since we have non power
   * of two cache sizes there. The size of larger slabs can be determined using
   * fls.
   */
  static s8 size_index[24] = {
  	3,	/* 8 */
  	4,	/* 16 */
  	5,	/* 24 */
  	5,	/* 32 */
  	6,	/* 40 */
  	6,	/* 48 */
  	6,	/* 56 */
  	6,	/* 64 */
  	1,	/* 72 */
  	1,	/* 80 */
  	1,	/* 88 */
  	1,	/* 96 */
  	7,	/* 104 */
  	7,	/* 112 */
  	7,	/* 120 */
  	7,	/* 128 */
  	2,	/* 136 */
  	2,	/* 144 */
  	2,	/* 152 */
  	2,	/* 160 */
  	2,	/* 168 */
  	2,	/* 176 */
  	2,	/* 184 */
  	2	/* 192 */
  };
  
  static inline int size_index_elem(size_t bytes)
  {
  	return (bytes - 1) / 8;
  }
  
  static struct kmem_cache *get_slab(size_t size, gfp_t flags)
  {
  	int index;
  
  	if (size <= 192) {
  		if (!size)
  			return ZERO_SIZE_PTR;
  
  		index = size_index[size_index_elem(size)];
  	} else
  		index = fls(size - 1);
  
  #ifdef CONFIG_ZONE_DMA
  	if (unlikely((flags & SLUB_DMA)))
  		return kmalloc_dma_caches[index];
  
  #endif
  	return kmalloc_caches[index];
  }
  
  void *__kmalloc(size_t size, gfp_t flags)
  {
  	struct kmem_cache *s;
  	void *ret;
  
  	if (unlikely(size > SLUB_MAX_SIZE))
  		return kmalloc_large(size, flags);
  
  	s = get_slab(size, flags);
  
  	if (unlikely(ZERO_OR_NULL_PTR(s)))
  		return s;
  
  	ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
  
  	trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
  
  	return ret;
  }
  EXPORT_SYMBOL(__kmalloc);
  
  #ifdef CONFIG_NUMA
  static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
  {
  	struct page *page;
  	void *ptr = NULL;
  
  	flags |= __GFP_COMP | __GFP_NOTRACK;
  	page = alloc_pages_node(node, flags, get_order(size));
  	if (page)
  		ptr = page_address(page);
  
  	kmemleak_alloc(ptr, size, 1, flags);
  	return ptr;
  }
  
  void *__kmalloc_node(size_t size, gfp_t flags, int node)
  {
  	struct kmem_cache *s;
  	void *ret;
  
  	if (unlikely(size > SLUB_MAX_SIZE)) {
  		ret = kmalloc_large_node(size, flags, node);
  
  		trace_kmalloc_node(_RET_IP_, ret,
  				   size, PAGE_SIZE << get_order(size),
  				   flags, node);
  
  		return ret;
  	}
  
  	s = get_slab(size, flags);
  
  	if (unlikely(ZERO_OR_NULL_PTR(s)))
  		return s;
  
  	ret = slab_alloc(s, flags, node, _RET_IP_);
  
  	trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
  
  	return ret;
  }
  EXPORT_SYMBOL(__kmalloc_node);
  #endif
  
  size_t ksize(const void *object)
  {
  	struct page *page;
  
  	if (unlikely(object == ZERO_SIZE_PTR))
  		return 0;
  
  	page = virt_to_head_page(object);
  
  	if (unlikely(!PageSlab(page))) {
  		WARN_ON(!PageCompound(page));
  		return PAGE_SIZE << compound_order(page);
  	}
  
  	return slab_ksize(page->slab);
  }
  EXPORT_SYMBOL(ksize);
  
  void kfree(const void *x)
  {
  	struct page *page;
  	void *object = (void *)x;
  
  	trace_kfree(_RET_IP_, x);
  
  	if (unlikely(ZERO_OR_NULL_PTR(x)))
  		return;
  
  	page = virt_to_head_page(x);
  	if (unlikely(!PageSlab(page))) {
  		BUG_ON(!PageCompound(page));
  		kmemleak_free(x);
  		put_page(page);
  		return;
  	}
  	slab_free(page->slab, page, object, _RET_IP_);
  }
  EXPORT_SYMBOL(kfree);
  
  /*
   * kmem_cache_shrink removes empty slabs from the partial lists and sorts
   * the remaining slabs by the number of items in use. The slabs with the
   * most items in use come first. New allocations will then fill those up
   * and thus they can be removed from the partial lists.
   *
   * The slabs with the least items are placed last. This results in them
   * being allocated from last increasing the chance that the last objects
   * are freed in them.
   */
  int kmem_cache_shrink(struct kmem_cache *s)
  {
  	int node;
  	int i;
  	struct kmem_cache_node *n;
  	struct page *page;
  	struct page *t;
  	int objects = oo_objects(s->max);
  	struct list_head *slabs_by_inuse =
  		kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
  	unsigned long flags;
  
  	if (!slabs_by_inuse)
  		return -ENOMEM;
  
  	flush_all(s);
  	for_each_node_state(node, N_NORMAL_MEMORY) {
  		n = get_node(s, node);
  
  		if (!n->nr_partial)
  			continue;
  
  		for (i = 0; i < objects; i++)
  			INIT_LIST_HEAD(slabs_by_inuse + i);
  
  		spin_lock_irqsave(&n->list_lock, flags);
  
  		/*
  		 * Build lists indexed by the items in use in each slab.
  		 *
  		 * Note that concurrent frees may occur while we hold the
  		 * 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);
  				discard_slab(s, page);
  			} else {
  				list_move(&page->lru,
  				slabs_by_inuse + page->inuse);
  			}
  		}
  
  		/*
  		 * Rebuild the partial list with the slabs filled up most
  		 * first and the least used slabs at the end.
  		 */
  		for (i = objects - 1; i >= 0; i--)
  			list_splice(slabs_by_inuse + i, n->partial.prev);
  
  		spin_unlock_irqrestore(&n->list_lock, flags);
  	}
  
  	kfree(slabs_by_inuse);
  	return 0;
  }
  EXPORT_SYMBOL(kmem_cache_shrink);
  
  #if defined(CONFIG_MEMORY_HOTPLUG)
  static int slab_mem_going_offline_callback(void *arg)
  {
  	struct kmem_cache *s;
  
  	down_read(&slub_lock);
  	list_for_each_entry(s, &slab_caches, list)
  		kmem_cache_shrink(s);
  	up_read(&slub_lock);
  
  	return 0;
  }
  
  static void slab_mem_offline_callback(void *arg)
  {
  	struct kmem_cache_node *n;
  	struct kmem_cache *s;
  	struct memory_notify *marg = arg;
  	int offline_node;
  
  	offline_node = marg->status_change_nid_normal;
  
  	/*
  	 * If the node still has available memory. we need kmem_cache_node
  	 * for it yet.
  	 */
  	if (offline_node < 0)
  		return;
  
  	down_read(&slub_lock);
  	list_for_each_entry(s, &slab_caches, list) {
  		n = get_node(s, offline_node);
  		if (n) {
  			/*
  			 * if n->nr_slabs > 0, slabs still exist on the node
  			 * that is going down. We were unable to free them,
  			 * and offline_pages() function shouldn't call this
  			 * callback. So, we must fail.
  			 */
  			BUG_ON(slabs_node(s, offline_node));
  
  			s->node[offline_node] = NULL;
  			kmem_cache_free(kmem_cache_node, n);
  		}
  	}
  	up_read(&slub_lock);
  }
  
  static int slab_mem_going_online_callback(void *arg)
  {
  	struct kmem_cache_node *n;
  	struct kmem_cache *s;
  	struct memory_notify *marg = arg;
  	int nid = marg->status_change_nid_normal;
  	int ret = 0;
  
  	/*
  	 * If the node's memory is already available, then kmem_cache_node is
  	 * already created. Nothing to do.
  	 */
  	if (nid < 0)
  		return 0;
  
  	/*
  	 * We are bringing a node online. No memory is available yet. We must
  	 * allocate a kmem_cache_node structure in order to bring the node
  	 * online.
  	 */
  	down_read(&slub_lock);
  	list_for_each_entry(s, &slab_caches, list) {
  		/*
  		 * XXX: kmem_cache_alloc_node will fallback to other nodes
  		 *      since memory is not yet available from the node that
  		 *      is brought up.
  		 */
  		n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
  		if (!n) {
  			ret = -ENOMEM;
  			goto out;
  		}
  		init_kmem_cache_node(n, s);
  		s->node[nid] = n;
  	}
  out:
  	up_read(&slub_lock);
  	return ret;
  }
  
  static int slab_memory_callback(struct notifier_block *self,
  				unsigned long action, void *arg)
  {
  	int ret = 0;
  
  	switch (action) {
  	case MEM_GOING_ONLINE:
  		ret = slab_mem_going_online_callback(arg);
  		break;
  	case MEM_GOING_OFFLINE:
  		ret = slab_mem_going_offline_callback(arg);
  		break;
  	case MEM_OFFLINE:
  	case MEM_CANCEL_ONLINE:
  		slab_mem_offline_callback(arg);
  		break;
  	case MEM_ONLINE:
  	case MEM_CANCEL_OFFLINE:
  		break;
  	}
  	if (ret)
  		ret = notifier_from_errno(ret);
  	else
  		ret = NOTIFY_OK;
  	return ret;
  }
  
  #endif /* CONFIG_MEMORY_HOTPLUG */
  
  /********************************************************************
   *			Basic setup of slabs
   *******************************************************************/
  
  /*
   * Used for early kmem_cache structures that were allocated using
   * the page allocator
   */
  
  static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s)
  {
  	int node;
  
  	list_add(&s->list, &slab_caches);
  	s->refcount = -1;
  
  	for_each_node_state(node, N_NORMAL_MEMORY) {
  		struct kmem_cache_node *n = get_node(s, node);
  		struct page *p;
  
  		if (n) {
  			list_for_each_entry(p, &n->partial, lru)
  				p->slab = s;
  
  #ifdef CONFIG_SLUB_DEBUG
  			list_for_each_entry(p, &n->full, lru)
  				p->slab = s;
  #endif
  		}
  	}
  }
  
  void __init kmem_cache_init(void)
  {
  	int i;
  	int caches = 0;
  	struct kmem_cache *temp_kmem_cache;
  	int order;
  	struct kmem_cache *temp_kmem_cache_node;
  	unsigned long kmalloc_size;
  
  	kmem_size = offsetof(struct kmem_cache, node) +
  				nr_node_ids * sizeof(struct kmem_cache_node *);
  
  	/* Allocate two kmem_caches from the page allocator */
  	kmalloc_size = ALIGN(kmem_size, cache_line_size());
  	order = get_order(2 * kmalloc_size);
  	kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
  
  	/*
  	 * Must first have the slab cache available for the allocations of the
  	 * struct kmem_cache_node's. There is special bootstrap code in
  	 * kmem_cache_open for slab_state == DOWN.
  	 */
  	kmem_cache_node = (void *)kmem_cache + kmalloc_size;
  
  	kmem_cache_open(kmem_cache_node, "kmem_cache_node",
  		sizeof(struct kmem_cache_node),
  		0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
  
  	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
  
  	/* Able to allocate the per node structures */
  	slab_state = PARTIAL;
  
  	temp_kmem_cache = kmem_cache;
  	kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
  		0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
  	kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
  	memcpy(kmem_cache, temp_kmem_cache, kmem_size);
  
  	/*
  	 * Allocate kmem_cache_node properly from the kmem_cache slab.
  	 * kmem_cache_node is separately allocated so no need to
  	 * update any list pointers.
  	 */
  	temp_kmem_cache_node = kmem_cache_node;
  
  	kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
  	memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
  
  	kmem_cache_bootstrap_fixup(kmem_cache_node);
  
  	caches++;
  	kmem_cache_bootstrap_fixup(kmem_cache);
  	caches++;
  	/* Free temporary boot structure */
  	free_pages((unsigned long)temp_kmem_cache, order);
  
  	/* Now we can use the kmem_cache to allocate kmalloc slabs */
  
  	/*
  	 * Patch up the size_index table if we have strange large alignment
  	 * requirements for the kmalloc array. This is only the case for
  	 * MIPS it seems. The standard arches will not generate any code here.
  	 *
  	 * Largest permitted alignment is 256 bytes due to the way we
  	 * handle the index determination for the smaller caches.
  	 *
  	 * Make sure that nothing crazy happens if someone starts tinkering
  	 * around with ARCH_KMALLOC_MINALIGN
  	 */
  	BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
  		(KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
  
  	for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
  		int elem = size_index_elem(i);
  		if (elem >= ARRAY_SIZE(size_index))
  			break;
  		size_index[elem] = KMALLOC_SHIFT_LOW;
  	}
  
  	if (KMALLOC_MIN_SIZE == 64) {
  		/*
  		 * The 96 byte size cache is not used if the alignment
  		 * is 64 byte.
  		 */
  		for (i = 64 + 8; i <= 96; i += 8)
  			size_index[size_index_elem(i)] = 7;
  	} else if (KMALLOC_MIN_SIZE == 128) {
  		/*
  		 * The 192 byte sized cache is not used if the alignment
  		 * is 128 byte. Redirect kmalloc to use the 256 byte cache
  		 * instead.
  		 */
  		for (i = 128 + 8; i <= 192; i += 8)
  			size_index[size_index_elem(i)] = 8;
  	}
  
  	/* Caches that are not of the two-to-the-power-of size */
  	if (KMALLOC_MIN_SIZE <= 32) {
  		kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
  		caches++;
  	}
  
  	if (KMALLOC_MIN_SIZE <= 64) {
  		kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
  		caches++;
  	}
  
  	for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
  		kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
  		caches++;
  	}
  
  	slab_state = UP;
  
  	/* Provide the correct kmalloc names now that the caches are up */
  	if (KMALLOC_MIN_SIZE <= 32) {
  		kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
  		BUG_ON(!kmalloc_caches[1]->name);
  	}
  
  	if (KMALLOC_MIN_SIZE <= 64) {
  		kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
  		BUG_ON(!kmalloc_caches[2]->name);
  	}
  
  	for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
  		char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
  
  		BUG_ON(!s);
  		kmalloc_caches[i]->name = s;
  	}
  
  #ifdef CONFIG_SMP
  	register_cpu_notifier(&slab_notifier);
  #endif
  
  #ifdef CONFIG_ZONE_DMA
  	for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
  		struct kmem_cache *s = kmalloc_caches[i];
  
  		if (s && s->size) {
  			char *name = kasprintf(GFP_NOWAIT,
  				 "dma-kmalloc-%d", s->objsize);
  
  			BUG_ON(!name);
  			kmalloc_dma_caches[i] = create_kmalloc_cache(name,
  				s->objsize, SLAB_CACHE_DMA);
  		}
  	}
  #endif
  	printk(KERN_INFO
  		"SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
  		" CPUs=%d, Nodes=%d\n",
  		caches, cache_line_size(),
  		slub_min_order, slub_max_order, slub_min_objects,
  		nr_cpu_ids, nr_node_ids);
  }
  
  void __init kmem_cache_init_late(void)
  {
  }
  
  /*
   * Find a mergeable slab cache
   */
  static int slab_unmergeable(struct kmem_cache *s)
  {
  	if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
  		return 1;
  
  	if (s->ctor)
  		return 1;
  
  	/*
  	 * We may have set a slab to be unmergeable during bootstrap.
  	 */
  	if (s->refcount < 0)
  		return 1;
  
  	return 0;
  }
  
  static struct kmem_cache *find_mergeable(size_t size,
  		size_t align, unsigned long flags, const char *name,
  		void (*ctor)(void *))
  {
  	struct kmem_cache *s;
  
  	if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
  		return NULL;
  
  	if (ctor)
  		return NULL;
  
  	size = ALIGN(size, sizeof(void *));
  	align = calculate_alignment(flags, align, size);
  	size = ALIGN(size, align);
  	flags = kmem_cache_flags(size, flags, name, NULL);
  
  	list_for_each_entry(s, &slab_caches, list) {
  		if (slab_unmergeable(s))
  			continue;
  
  		if (size > s->size)
  			continue;
  
  		if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
  				continue;
  		/*
  		 * Check if alignment is compatible.
  		 * Courtesy of Adrian Drzewiecki
  		 */
  		if ((s->size & ~(align - 1)) != s->size)
  			continue;
  
  		if (s->size - size >= sizeof(void *))
  			continue;
  
  		return s;
  	}
  	return NULL;
  }
  
  struct kmem_cache *kmem_cache_create(const char *name, size_t size,
  		size_t align, unsigned long flags, void (*ctor)(void *))
  {
  	struct kmem_cache *s;
  	char *n;
  
  	if (WARN_ON(!name))
  		return NULL;
  
  	down_write(&slub_lock);
  	s = find_mergeable(size, align, flags, name, ctor);
  	if (s) {
  		s->refcount++;
  		/*
  		 * Adjust the object sizes so that we clear
  		 * the complete object on kzalloc.
  		 */
  		s->objsize = max(s->objsize, (int)size);
  		s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
  
  		if (sysfs_slab_alias(s, name)) {
  			s->refcount--;
  			goto err;
  		}
  		up_write(&slub_lock);
  		return s;
  	}
  
  	n = kstrdup(name, GFP_KERNEL);
  	if (!n)
  		goto err;
  
  	s = kmalloc(kmem_size, GFP_KERNEL);
  	if (s) {
  		if (kmem_cache_open(s, n,
  				size, align, flags, ctor)) {
  			list_add(&s->list, &slab_caches);
  			up_write(&slub_lock);
  			if (sysfs_slab_add(s)) {
  				down_write(&slub_lock);
  				list_del(&s->list);
  				kfree(n);
  				kfree(s);
  				goto err;
  			}
  			return s;
  		}
  		kfree(n);
  		kfree(s);
  	}
  err:
  	up_write(&slub_lock);
  
  	if (flags & SLAB_PANIC)
  		panic("Cannot create slabcache %s\n", name);
  	else
  		s = NULL;
  	return s;
  }
  EXPORT_SYMBOL(kmem_cache_create);
  
  #ifdef CONFIG_SMP
  /*
   * Use the cpu notifier to insure that the cpu slabs are flushed when
   * necessary.
   */
  static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
  		unsigned long action, void *hcpu)
  {
  	long cpu = (long)hcpu;
  	struct kmem_cache *s;
  	unsigned long flags;
  
  	switch (action) {
  	case CPU_UP_CANCELED:
  	case CPU_UP_CANCELED_FROZEN:
  	case CPU_DEAD:
  	case CPU_DEAD_FROZEN:
  		down_read(&slub_lock);
  		list_for_each_entry(s, &slab_caches, list) {
  			local_irq_save(flags);
  			__flush_cpu_slab(s, cpu);
  			local_irq_restore(flags);
  		}
  		up_read(&slub_lock);
  		break;
  	default:
  		break;
  	}
  	return NOTIFY_OK;
  }
  
  static struct notifier_block __cpuinitdata slab_notifier = {
  	.notifier_call = slab_cpuup_callback
  };
  
  #endif
  
  void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
  {
  	struct kmem_cache *s;
  	void *ret;
  
  	if (unlikely(size > SLUB_MAX_SIZE))
  		return kmalloc_large(size, gfpflags);
  
  	s = get_slab(size, gfpflags);
  
  	if (unlikely(ZERO_OR_NULL_PTR(s)))
  		return s;
  
  	ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, caller);
  
  	/* Honor the call site pointer we received. */
  	trace_kmalloc(caller, ret, size, s->size, gfpflags);
  
  	return ret;
  }
  
  #ifdef CONFIG_NUMA
  void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
  					int node, unsigned long caller)
  {
  	struct kmem_cache *s;
  	void *ret;
  
  	if (unlikely(size > SLUB_MAX_SIZE)) {
  		ret = kmalloc_large_node(size, gfpflags, node);
  
  		trace_kmalloc_node(caller, ret,
  				   size, PAGE_SIZE << get_order(size),
  				   gfpflags, node);
  
  		return ret;
  	}
  
  	s = get_slab(size, gfpflags);
  
  	if (unlikely(ZERO_OR_NULL_PTR(s)))
  		return s;
  
  	ret = slab_alloc(s, gfpflags, node, caller);
  
  	/* Honor the call site pointer we received. */
  	trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
  
  	return ret;
  }
  #endif
  
  #ifdef CONFIG_SYSFS
  static int count_inuse(struct page *page)
  {
  	return page->inuse;
  }
  
  static int count_total(struct page *page)
  {
  	return page->objects;
  }
  #endif
  
  #ifdef CONFIG_SLUB_DEBUG
  static int validate_slab(struct kmem_cache *s, struct page *page,
  						unsigned long *map)
  {
  	void *p;
  	void *addr = page_address(page);
  
  	if (!check_slab(s, page) ||
  			!on_freelist(s, page, NULL))
  		return 0;
  
  	/* Now we know that a valid freelist exists */
  	bitmap_zero(map, page->objects);
  
  	get_map(s, page, map);
  	for_each_object(p, s, addr, page->objects) {
  		if (test_bit(slab_index(p, s, addr), map))
  			if (!check_object(s, page, p, SLUB_RED_INACTIVE))
  				return 0;
  	}
  
  	for_each_object(p, s, addr, page->objects)
  		if (!test_bit(slab_index(p, s, addr), map))
  			if (!check_object(s, page, p, SLUB_RED_ACTIVE))
  				return 0;
  	return 1;
  }
  
  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);
  }
  
  static int validate_slab_node(struct kmem_cache *s,
  		struct kmem_cache_node *n, unsigned long *map)
  {
  	unsigned long count = 0;
  	struct page *page;
  	unsigned long flags;
  
  	spin_lock_irqsave(&n->list_lock, flags);
  
  	list_for_each_entry(page, &n->partial, lru) {
  		validate_slab_slab(s, page, map);
  		count++;
  	}
  	if (count != n->nr_partial)
  		printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
  			"counter=%ld\n", s->name, count, n->nr_partial);
  
  	if (!(s->flags & SLAB_STORE_USER))
  		goto out;
  
  	list_for_each_entry(page, &n->full, lru) {
  		validate_slab_slab(s, page, map);
  		count++;
  	}
  	if (count != atomic_long_read(&n->nr_slabs))
  		printk(KERN_ERR "SLUB: %s %ld slabs counted but "
  			"counter=%ld\n", s->name, count,
  			atomic_long_read(&n->nr_slabs));
  
  out:
  	spin_unlock_irqrestore(&n->list_lock, flags);
  	return count;
  }
  
  static long validate_slab_cache(struct kmem_cache *s)
  {
  	int node;
  	unsigned long count = 0;
  	unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
  				sizeof(unsigned long), GFP_KERNEL);
  
  	if (!map)
  		return -ENOMEM;
  
  	flush_all(s);
  	for_each_node_state(node, N_NORMAL_MEMORY) {
  		struct kmem_cache_node *n = get_node(s, node);
  
  		count += validate_slab_node(s, n, map);
  	}
  	kfree(map);
  	return count;
  }
  /*
   * Generate lists of code addresses where slabcache objects are allocated
   * and freed.
   */
  
  struct location {
  	unsigned long count;
  	unsigned long addr;
  	long long sum_time;
  	long min_time;
  	long max_time;
  	long min_pid;
  	long max_pid;
  	DECLARE_BITMAP(cpus, NR_CPUS);
  	nodemask_t nodes;
  };
  
  struct loc_track {
  	unsigned long max;
  	unsigned long count;
  	struct location *loc;
  };
  
  static void free_loc_track(struct loc_track *t)
  {
  	if (t->max)
  		free_pages((unsigned long)t->loc,
  			get_order(sizeof(struct location) * t->max));
  }
  
  static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
  {
  	struct location *l;
  	int order;
  
  	order = get_order(sizeof(struct location) * max);
  
  	l = (void *)__get_free_pages(flags, order);
  	if (!l)
  		return 0;
  
  	if (t->count) {
  		memcpy(l, t->loc, sizeof(struct location) * t->count);
  		free_loc_track(t);
  	}
  	t->max = max;
  	t->loc = l;
  	return 1;
  }
  
  static int add_location(struct loc_track *t, struct kmem_cache *s,
  				const struct track *track)
  {
  	long start, end, pos;
  	struct location *l;
  	unsigned long caddr;
  	unsigned long age = jiffies - track->when;
  
  	start = -1;
  	end = t->count;
  
  	for ( ; ; ) {
  		pos = start + (end - start + 1) / 2;
  
  		/*
  		 * There is nothing at "end". If we end up there
  		 * we need to add something to before end.
  		 */
  		if (pos == end)
  			break;
  
  		caddr = t->loc[pos].addr;
  		if (track->addr == caddr) {
  
  			l = &t->loc[pos];
  			l->count++;
  			if (track->when) {
  				l->sum_time += age;
  				if (age < l->min_time)
  					l->min_time = age;
  				if (age > l->max_time)
  					l->max_time = age;
  
  				if (track->pid < l->min_pid)
  					l->min_pid = track->pid;
  				if (track->pid > l->max_pid)
  					l->max_pid = track->pid;
  
  				cpumask_set_cpu(track->cpu,
  						to_cpumask(l->cpus));
  			}
  			node_set(page_to_nid(virt_to_page(track)), l->nodes);
  			return 1;
  		}
  
  		if (track->addr < caddr)
  			end = pos;
  		else
  			start = pos;
  	}
  
  	/*
  	 * Not found. Insert new tracking element.
  	 */
  	if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
  		return 0;
  
  	l = t->loc + pos;
  	if (pos < t->count)
  		memmove(l + 1, l,
  			(t->count - pos) * sizeof(struct location));
  	t->count++;
  	l->count = 1;
  	l->addr = track->addr;
  	l->sum_time = age;
  	l->min_time = age;
  	l->max_time = age;
  	l->min_pid = track->pid;
  	l->max_pid = track->pid;
  	cpumask_clear(to_cpumask(l->cpus));
  	cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
  	nodes_clear(l->nodes);
  	node_set(page_to_nid(virt_to_page(track)), l->nodes);
  	return 1;
  }
  
  static void process_slab(struct loc_track *t, struct kmem_cache *s,
  		struct page *page, enum track_item alloc,
  		unsigned long *map)
  {
  	void *addr = page_address(page);
  	void *p;
  
  	bitmap_zero(map, page->objects);
  	get_map(s, page, map);
  
  	for_each_object(p, s, addr, page->objects)
  		if (!test_bit(slab_index(p, s, addr), map))
  			add_location(t, s, get_track(s, p, alloc));
  }
  
  static int list_locations(struct kmem_cache *s, char *buf,
  					enum track_item alloc)
  {
  	int len = 0;
  	unsigned long i;
  	struct loc_track t = { 0, 0, NULL };
  	int node;
  	unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
  				     sizeof(unsigned long), GFP_KERNEL);
  
  	if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
  				     GFP_TEMPORARY)) {
  		kfree(map);
  		return sprintf(buf, "Out of memory\n");
  	}
  	/* Push back cpu slabs */
  	flush_all(s);
  
  	for_each_node_state(node, N_NORMAL_MEMORY) {
  		struct kmem_cache_node *n = get_node(s, node);
  		unsigned long flags;
  		struct page *page;
  
  		if (!atomic_long_read(&n->nr_slabs))
  			continue;
  
  		spin_lock_irqsave(&n->list_lock, flags);
  		list_for_each_entry(page, &n->partial, lru)
  			process_slab(&t, s, page, alloc, map);
  		list_for_each_entry(page, &n->full, lru)
  			process_slab(&t, s, page, alloc, map);
  		spin_unlock_irqrestore(&n->list_lock, flags);
  	}
  
  	for (i = 0; i < t.count; i++) {
  		struct location *l = &t.loc[i];
  
  		if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
  			break;
  		len += sprintf(buf + len, "%7ld ", l->count);
  
  		if (l->addr)
  			len += sprintf(buf + len, "%pS", (void *)l->addr);
  		else
  			len += sprintf(buf + len, "<not-available>");
  
  		if (l->sum_time != l->min_time) {
  			len += sprintf(buf + len, " age=%ld/%ld/%ld",
  				l->min_time,
  				(long)div_u64(l->sum_time, l->count),
  				l->max_time);
  		} else
  			len += sprintf(buf + len, " age=%ld",
  				l->min_time);
  
  		if (l->min_pid != l->max_pid)
  			len += sprintf(buf + len, " pid=%ld-%ld",
  				l->min_pid, l->max_pid);
  		else
  			len += sprintf(buf + len, " pid=%ld",
  				l->min_pid);
  
  		if (num_online_cpus() > 1 &&
  				!cpumask_empty(to_cpumask(l->cpus)) &&
  				len < PAGE_SIZE - 60) {
  			len += sprintf(buf + len, " cpus=");
  			len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
  						 to_cpumask(l->cpus));
  		}
  
  		if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
  				len < PAGE_SIZE - 60) {
  			len += sprintf(buf + len, " nodes=");
  			len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
  					l->nodes);
  		}
  
  		len += sprintf(buf + len, "\n");
  	}
  
  	free_loc_track(&t);
  	kfree(map);
  	if (!t.count)
  		len += sprintf(buf, "No data\n");
  	return len;
  }
  #endif
  
  #ifdef SLUB_RESILIENCY_TEST
  static void resiliency_test(void)
  {
  	u8 *p;
  
  	BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
  
  	printk(KERN_ERR "SLUB resiliency testing\n");
  	printk(KERN_ERR "-----------------------\n");
  	printk(KERN_ERR "A. Corruption after allocation\n");
  
  	p = kzalloc(16, GFP_KERNEL);
  	p[16] = 0x12;
  	printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
  			" 0x12->0x%p\n\n", p + 16);
  
  	validate_slab_cache(kmalloc_caches[4]);
  
  	/* Hmmm... The next two are dangerous */
  	p = kzalloc(32, GFP_KERNEL);
  	p[32 + sizeof(void *)] = 0x34;
  	printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
  			" 0x34 -> -0x%p\n", p);
  	printk(KERN_ERR
  		"If allocated object is overwritten then not detectable\n\n");
  
  	validate_slab_cache(kmalloc_caches[5]);
  	p = kzalloc(64, GFP_KERNEL);
  	p += 64 + (get_cycles() & 0xff) * sizeof(void *);
  	*p = 0x56;
  	printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
  									p);
  	printk(KERN_ERR
  		"If allocated object is overwritten then not detectable\n\n");
  	validate_slab_cache(kmalloc_caches[6]);
  
  	printk(KERN_ERR "\nB. Corruption after free\n");
  	p = kzalloc(128, GFP_KERNEL);
  	kfree(p);
  	*p = 0x78;
  	printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
  	validate_slab_cache(kmalloc_caches[7]);
  
  	p = kzalloc(256, GFP_KERNEL);
  	kfree(p);
  	p[50] = 0x9a;
  	printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
  			p);
  	validate_slab_cache(kmalloc_caches[8]);
  
  	p = kzalloc(512, GFP_KERNEL);
  	kfree(p);
  	p[512] = 0xab;
  	printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
  	validate_slab_cache(kmalloc_caches[9]);
  }
  #else
  #ifdef CONFIG_SYSFS
  static void resiliency_test(void) {};
  #endif
  #endif
  
  #ifdef CONFIG_SYSFS
  enum slab_stat_type {
  	SL_ALL,			/* All slabs */
  	SL_PARTIAL,		/* Only partially allocated slabs */
  	SL_CPU,			/* Only slabs used for cpu caches */
  	SL_OBJECTS,		/* Determine allocated objects not slabs */
  	SL_TOTAL		/* Determine object capacity not slabs */
  };
  
  #define SO_ALL		(1 << SL_ALL)
  #define SO_PARTIAL	(1 << SL_PARTIAL)
  #define SO_CPU		(1 << SL_CPU)
  #define SO_OBJECTS	(1 << SL_OBJECTS)
  #define SO_TOTAL	(1 << SL_TOTAL)
  
  static ssize_t show_slab_objects(struct kmem_cache *s,
  			    char *buf, unsigned long flags)
  {
  	unsigned long total = 0;
  	int node;
  	int x;
  	unsigned long *nodes;
  	unsigned long *per_cpu;
  
  	nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
  	if (!nodes)
  		return -ENOMEM;
  	per_cpu = nodes + nr_node_ids;
  
  	if (flags & SO_CPU) {
  		int cpu;
  
  		for_each_possible_cpu(cpu) {
  			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
  
  			if (!c || c->node < 0)
  				continue;
  
  			if (c->page) {
  					if (flags & SO_TOTAL)
  						x = c->page->objects;
  				else if (flags & SO_OBJECTS)
  					x = c->page->inuse;
  				else
  					x = 1;
  
  				total += x;
  				nodes[c->node] += x;
  			}
  			per_cpu[c->node]++;
  		}
  	}
  
  	lock_memory_hotplug();
  #ifdef CONFIG_SLUB_DEBUG
  	if (flags & SO_ALL) {
  		for_each_node_state(node, N_NORMAL_MEMORY) {
  			struct kmem_cache_node *n = get_node(s, node);
  
  		if (flags & SO_TOTAL)
  			x = atomic_long_read(&n->total_objects);
  		else if (flags & SO_OBJECTS)
  			x = atomic_long_read(&n->total_objects) -
  				count_partial(n, count_free);
  
  			else
  				x = atomic_long_read(&n->nr_slabs);
  			total += x;
  			nodes[node] += x;
  		}
  
  	} else
  #endif
  	if (flags & SO_PARTIAL) {
  		for_each_node_state(node, N_NORMAL_MEMORY) {
  			struct kmem_cache_node *n = get_node(s, node);
  
  			if (flags & SO_TOTAL)
  				x = count_partial(n, count_total);
  			else if (flags & SO_OBJECTS)
  				x = count_partial(n, count_inuse);
  			else
  				x = n->nr_partial;
  			total += x;
  			nodes[node] += x;
  		}
  	}
  	x = sprintf(buf, "%lu", total);
  #ifdef CONFIG_NUMA
  	for_each_node_state(node, N_NORMAL_MEMORY)
  		if (nodes[node])
  			x += sprintf(buf + x, " N%d=%lu",
  					node, nodes[node]);
  #endif
  	unlock_memory_hotplug();
  	kfree(nodes);
  	return x + sprintf(buf + x, "\n");
  }
  
  #ifdef CONFIG_SLUB_DEBUG
  static int any_slab_objects(struct kmem_cache *s)
  {
  	int node;
  
  	for_each_online_node(node) {
  		struct kmem_cache_node *n = get_node(s, node);
  
  		if (!n)
  			continue;
  
  		if (atomic_long_read(&n->total_objects))
  			return 1;
  	}
  	return 0;
  }
  #endif
  
  #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
  #define to_slab(n) container_of(n, struct kmem_cache, kobj);
  
  struct slab_attribute {
  	struct attribute attr;
  	ssize_t (*show)(struct kmem_cache *s, char *buf);
  	ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
  };
  
  #define SLAB_ATTR_RO(_name) \
  	static struct slab_attribute _name##_attr = __ATTR_RO(_name)
  
  #define SLAB_ATTR(_name) \
  	static struct slab_attribute _name##_attr =  \
  	__ATTR(_name, 0644, _name##_show, _name##_store)
  
  static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", s->size);
  }
  SLAB_ATTR_RO(slab_size);
  
  static ssize_t align_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", s->align);
  }
  SLAB_ATTR_RO(align);
  
  static ssize_t object_size_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", s->objsize);
  }
  SLAB_ATTR_RO(object_size);
  
  static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", oo_objects(s->oo));
  }
  SLAB_ATTR_RO(objs_per_slab);
  
  static ssize_t order_store(struct kmem_cache *s,
  				const char *buf, size_t length)
  {
  	unsigned long order;
  	int err;
  
  	err = strict_strtoul(buf, 10, &order);
  	if (err)
  		return err;
  
  	if (order > slub_max_order || order < slub_min_order)
  		return -EINVAL;
  
  	calculate_sizes(s, order);
  	return length;
  }
  
  static ssize_t order_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", oo_order(s->oo));
  }
  SLAB_ATTR(order);
  
  static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%lu\n", s->min_partial);
  }
  
  static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
  				 size_t length)
  {
  	unsigned long min;
  	int err;
  
  	err = strict_strtoul(buf, 10, &min);
  	if (err)
  		return err;
  
  	set_min_partial(s, min);
  	return length;
  }
  SLAB_ATTR(min_partial);
  
  static ssize_t ctor_show(struct kmem_cache *s, char *buf)
  {
  	if (!s->ctor)
  		return 0;
  	return sprintf(buf, "%pS\n", s->ctor);
  }
  SLAB_ATTR_RO(ctor);
  
  static ssize_t aliases_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", s->refcount - 1);
  }
  SLAB_ATTR_RO(aliases);
  
  static ssize_t partial_show(struct kmem_cache *s, char *buf)
  {
  	return show_slab_objects(s, buf, SO_PARTIAL);
  }
  SLAB_ATTR_RO(partial);
  
  static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
  {
  	return show_slab_objects(s, buf, SO_CPU);
  }
  SLAB_ATTR_RO(cpu_slabs);
  
  static ssize_t objects_show(struct kmem_cache *s, char *buf)
  {
  	return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
  }
  SLAB_ATTR_RO(objects);
  
  static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
  {
  	return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
  }
  SLAB_ATTR_RO(objects_partial);
  
  static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
  }
  
  static ssize_t reclaim_account_store(struct kmem_cache *s,
  				const char *buf, size_t length)
  {
  	s->flags &= ~SLAB_RECLAIM_ACCOUNT;
  	if (buf[0] == '1')
  		s->flags |= SLAB_RECLAIM_ACCOUNT;
  	return length;
  }
  SLAB_ATTR(reclaim_account);
  
  static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
  }
  SLAB_ATTR_RO(hwcache_align);
  
  #ifdef CONFIG_ZONE_DMA
  static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
  }
  SLAB_ATTR_RO(cache_dma);
  #endif
  
  static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
  }
  SLAB_ATTR_RO(destroy_by_rcu);
  
  static ssize_t reserved_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", s->reserved);
  }
  SLAB_ATTR_RO(reserved);
  
  #ifdef CONFIG_SLUB_DEBUG
  static ssize_t slabs_show(struct kmem_cache *s, char *buf)
  {
  	return show_slab_objects(s, buf, SO_ALL);
  }
  SLAB_ATTR_RO(slabs);
  
  static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
  {
  	return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
  }
  SLAB_ATTR_RO(total_objects);
  
  static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
  }
  
  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')
  		s->flags |= SLAB_DEBUG_FREE;
  	return length;
  }
  SLAB_ATTR(sanity_checks);
  
  static ssize_t trace_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
  }
  
  static ssize_t trace_store(struct kmem_cache *s, const char *buf,
  							size_t length)
  {
  	s->flags &= ~SLAB_TRACE;
  	if (buf[0] == '1')
  		s->flags |= SLAB_TRACE;
  	return length;
  }
  SLAB_ATTR(trace);
  
  static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
  }
  
  static ssize_t red_zone_store(struct kmem_cache *s,
  				const char *buf, size_t length)
  {
  	if (any_slab_objects(s))
  		return -EBUSY;
  
  	s->flags &= ~SLAB_RED_ZONE;
  	if (buf[0] == '1')
  		s->flags |= SLAB_RED_ZONE;
  	calculate_sizes(s, -1);
  	return length;
  }
  SLAB_ATTR(red_zone);
  
  static ssize_t poison_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
  }
  
  static ssize_t poison_store(struct kmem_cache *s,
  				const char *buf, size_t length)
  {
  	if (any_slab_objects(s))
  		return -EBUSY;
  
  	s->flags &= ~SLAB_POISON;
  	if (buf[0] == '1')
  		s->flags |= SLAB_POISON;
  	calculate_sizes(s, -1);
  	return length;
  }
  SLAB_ATTR(poison);
  
  static ssize_t store_user_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
  }
  
  static ssize_t store_user_store(struct kmem_cache *s,
  				const char *buf, size_t length)
  {
  	if (any_slab_objects(s))
  		return -EBUSY;
  
  	s->flags &= ~SLAB_STORE_USER;
  	if (buf[0] == '1')
  		s->flags |= SLAB_STORE_USER;
  	calculate_sizes(s, -1);
  	return length;
  }
  SLAB_ATTR(store_user);
  
  static ssize_t validate_show(struct kmem_cache *s, char *buf)
  {
  	return 0;
  }
  
  static ssize_t validate_store(struct kmem_cache *s,
  			const char *buf, size_t length)
  {
  	int ret = -EINVAL;
  
  	if (buf[0] == '1') {
  		ret = validate_slab_cache(s);
  		if (ret >= 0)
  			ret = length;
  	}
  	return ret;
  }
  SLAB_ATTR(validate);
  
  static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
  {
  	if (!(s->flags & SLAB_STORE_USER))
  		return -ENOSYS;
  	return list_locations(s, buf, TRACK_ALLOC);
  }
  SLAB_ATTR_RO(alloc_calls);
  
  static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
  {
  	if (!(s->flags & SLAB_STORE_USER))
  		return -ENOSYS;
  	return list_locations(s, buf, TRACK_FREE);
  }
  SLAB_ATTR_RO(free_calls);
  #endif /* CONFIG_SLUB_DEBUG */
  
  #ifdef CONFIG_FAILSLAB
  static ssize_t failslab_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
  }
  
  static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
  							size_t length)
  {
  	s->flags &= ~SLAB_FAILSLAB;
  	if (buf[0] == '1')
  		s->flags |= SLAB_FAILSLAB;
  	return length;
  }
  SLAB_ATTR(failslab);
  #endif
  
  static ssize_t shrink_show(struct kmem_cache *s, char *buf)
  {
  	return 0;
  }
  
  static ssize_t shrink_store(struct kmem_cache *s,
  			const char *buf, size_t length)
  {
  	if (buf[0] == '1') {
  		int rc = kmem_cache_shrink(s);
  
  		if (rc)
  			return rc;
  	} else
  		return -EINVAL;
  	return length;
  }
  SLAB_ATTR(shrink);
  
  #ifdef CONFIG_NUMA
  static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
  {
  	return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
  }
  
  static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
  				const char *buf, size_t length)
  {
  	unsigned long ratio;
  	int err;
  
  	err = strict_strtoul(buf, 10, &ratio);
  	if (err)
  		return err;
  
  	if (ratio <= 100)
  		s->remote_node_defrag_ratio = ratio * 10;
  
  	return length;
  }
  SLAB_ATTR(remote_node_defrag_ratio);
  #endif
  
  #ifdef CONFIG_SLUB_STATS
  static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
  {
  	unsigned long sum  = 0;
  	int cpu;
  	int len;
  	int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
  
  	if (!data)
  		return -ENOMEM;
  
  	for_each_online_cpu(cpu) {
  		unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
  
  		data[cpu] = x;
  		sum += x;
  	}
  
  	len = sprintf(buf, "%lu", sum);
  
  #ifdef CONFIG_SMP
  	for_each_online_cpu(cpu) {
  		if (data[cpu] && len < PAGE_SIZE - 20)
  			len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
  	}
  #endif
  	kfree(data);
  	return len + sprintf(buf + len, "\n");
  }
  
  static void clear_stat(struct kmem_cache *s, enum stat_item si)
  {
  	int cpu;
  
  	for_each_online_cpu(cpu)
  		per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
  }
  
  #define STAT_ATTR(si, text) 					\
  static ssize_t text##_show(struct kmem_cache *s, char *buf)	\
  {								\
  	return show_stat(s, buf, si);				\
  }								\
  static ssize_t text##_store(struct kmem_cache *s,		\
  				const char *buf, size_t length)	\
  {								\
  	if (buf[0] != '0')					\
  		return -EINVAL;					\
  	clear_stat(s, si);					\
  	return length;						\
  }								\
  SLAB_ATTR(text);						\
  
  STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
  STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
  STAT_ATTR(FREE_FASTPATH, free_fastpath);
  STAT_ATTR(FREE_SLOWPATH, free_slowpath);
  STAT_ATTR(FREE_FROZEN, free_frozen);
  STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
  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(FREE_SLAB, free_slab);
  STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
  STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
  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(ORDER_FALLBACK, order_fallback);
  #endif
  
  static struct attribute *slab_attrs[] = {
  	&slab_size_attr.attr,
  	&object_size_attr.attr,
  	&objs_per_slab_attr.attr,
  	&order_attr.attr,
  	&min_partial_attr.attr,
  	&objects_attr.attr,
  	&objects_partial_attr.attr,
  	&partial_attr.attr,
  	&cpu_slabs_attr.attr,
  	&ctor_attr.attr,
  	&aliases_attr.attr,
  	&align_attr.attr,
  	&hwcache_align_attr.attr,
  	&reclaim_account_attr.attr,
  	&destroy_by_rcu_attr.attr,
  	&shrink_attr.attr,
  	&reserved_attr.attr,
  #ifdef CONFIG_SLUB_DEBUG
  	&total_objects_attr.attr,
  	&slabs_attr.attr,
  	&sanity_checks_attr.attr,
  	&trace_attr.attr,
  	&red_zone_attr.attr,
  	&poison_attr.attr,
  	&store_user_attr.attr,
  	&validate_attr.attr,
  	&alloc_calls_attr.attr,
  	&free_calls_attr.attr,
  #endif
  #ifdef CONFIG_ZONE_DMA
  	&cache_dma_attr.attr,
  #endif
  #ifdef CONFIG_NUMA
  	&remote_node_defrag_ratio_attr.attr,
  #endif
  #ifdef CONFIG_SLUB_STATS
  	&alloc_fastpath_attr.attr,
  	&alloc_slowpath_attr.attr,
  	&free_fastpath_attr.attr,
  	&free_slowpath_attr.attr,
  	&free_frozen_attr.attr,
  	&free_add_partial_attr.attr,
  	&free_remove_partial_attr.attr,
  	&alloc_from_partial_attr.attr,
  	&alloc_slab_attr.attr,
  	&alloc_refill_attr.attr,
  	&free_slab_attr.attr,
  	&cpuslab_flush_attr.attr,
  	&deactivate_full_attr.attr,
  	&deactivate_empty_attr.attr,
  	&deactivate_to_head_attr.attr,
  	&deactivate_to_tail_attr.attr,
  	&deactivate_remote_frees_attr.attr,
  	&order_fallback_attr.attr,
  #endif
  #ifdef CONFIG_FAILSLAB
  	&failslab_attr.attr,
  #endif
  
  	NULL
  };
  
  static struct attribute_group slab_attr_group = {
  	.attrs = slab_attrs,
  };
  
  static ssize_t slab_attr_show(struct kobject *kobj,
  				struct attribute *attr,
  				char *buf)
  {
  	struct slab_attribute *attribute;
  	struct kmem_cache *s;
  	int err;
  
  	attribute = to_slab_attr(attr);
  	s = to_slab(kobj);
  
  	if (!attribute->show)
  		return -EIO;
  
  	err = attribute->show(s, buf);
  
  	return err;
  }
  
  static ssize_t slab_attr_store(struct kobject *kobj,
  				struct attribute *attr,
  				const char *buf, size_t len)
  {
  	struct slab_attribute *attribute;
  	struct kmem_cache *s;
  	int err;
  
  	attribute = to_slab_attr(attr);
  	s = to_slab(kobj);
  
  	if (!attribute->store)
  		return -EIO;
  
  	err = attribute->store(s, buf, len);
  
  	return err;
  }
  
  static void kmem_cache_release(struct kobject *kobj)
  {
  	struct kmem_cache *s = to_slab(kobj);
  
  	kfree(s->name);
  	kfree(s);
  }
  
  static const struct sysfs_ops slab_sysfs_ops = {
  	.show = slab_attr_show,
  	.store = slab_attr_store,
  };
  
  static struct kobj_type slab_ktype = {
  	.sysfs_ops = &slab_sysfs_ops,
  	.release = kmem_cache_release
  };
  
  static int uevent_filter(struct kset *kset, struct kobject *kobj)
  {
  	struct kobj_type *ktype = get_ktype(kobj);
  
  	if (ktype == &slab_ktype)
  		return 1;
  	return 0;
  }
  
  static const struct kset_uevent_ops slab_uevent_ops = {
  	.filter = uevent_filter,
  };
  
  static struct kset *slab_kset;
  
  #define ID_STR_LENGTH 64
  
  /* Create a unique string id for a slab cache:
   *
   * Format	:[flags-]size
   */
  static char *create_unique_id(struct kmem_cache *s)
  {
  	char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
  	char *p = name;
  
  	BUG_ON(!name);
  
  	*p++ = ':';
  	/*
  	 * First flags affecting slabcache operations. We will only
  	 * get here for aliasable slabs so we do not need to support
  	 * too many flags. The flags here must cover all flags that
  	 * are matched during merging to guarantee that the id is
  	 * unique.
  	 */
  	if (s->flags & SLAB_CACHE_DMA)
  		*p++ = 'd';
  	if (s->flags & SLAB_RECLAIM_ACCOUNT)
  		*p++ = 'a';
  	if (s->flags & SLAB_DEBUG_FREE)
  		*p++ = 'F';
  	if (!(s->flags & SLAB_NOTRACK))
  		*p++ = 't';
  	if (p != name + 1)
  		*p++ = '-';
  	p += sprintf(p, "%07d", s->size);
  	BUG_ON(p > name + ID_STR_LENGTH - 1);
  	return name;
  }
  
  static int sysfs_slab_add(struct kmem_cache *s)
  {
  	int err;
  	const char *name;
  	int unmergeable;
  
  	if (slab_state < SYSFS)
  		/* Defer until later */
  		return 0;
  
  	unmergeable = slab_unmergeable(s);
  	if (unmergeable) {
  		/*
  		 * Slabcache can never be merged so we can use the name proper.
  		 * This is typically the case for debug situations. In that
  		 * case we can catch duplicate names easily.
  		 */
  		sysfs_remove_link(&slab_kset->kobj, s->name);
  		name = s->name;
  	} else {
  		/*
  		 * Create a unique name for the slab as a target
  		 * for the symlinks.
  		 */
  		name = create_unique_id(s);
  	}
  
  	s->kobj.kset = slab_kset;
  	err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
  	if (err) {
  		kobject_put(&s->kobj);
  		return err;
  	}
  
  	err = sysfs_create_group(&s->kobj, &slab_attr_group);
  	if (err) {
  		kobject_del(&s->kobj);
  		kobject_put(&s->kobj);
  		return err;
  	}
  	kobject_uevent(&s->kobj, KOBJ_ADD);
  	if (!unmergeable) {
  		/* Setup first alias */
  		sysfs_slab_alias(s, s->name);
  		kfree(name);
  	}
  	return 0;
  }
  
  static void sysfs_slab_remove(struct kmem_cache *s)
  {
  	if (slab_state < SYSFS)
  		/*
  		 * Sysfs has not been setup yet so no need to remove the
  		 * cache from sysfs.
  		 */
  		return;
  
  	kobject_uevent(&s->kobj, KOBJ_REMOVE);
  	kobject_del(&s->kobj);
  	kobject_put(&s->kobj);
  }
  
  /*
   * Need to buffer aliases during bootup until sysfs becomes
   * available lest we lose that information.
   */
  struct saved_alias {
  	struct kmem_cache *s;
  	const char *name;
  	struct saved_alias *next;
  };
  
  static struct saved_alias *alias_list;
  
  static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
  {
  	struct saved_alias *al;
  
  	if (slab_state == SYSFS) {
  		/*
  		 * If we have a leftover link then remove it.
  		 */
  		sysfs_remove_link(&slab_kset->kobj, name);
  		return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
  	}
  
  	al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
  	if (!al)
  		return -ENOMEM;
  
  	al->s = s;
  	al->name = name;
  	al->next = alias_list;
  	alias_list = al;
  	return 0;
  }
  
  static int __init slab_sysfs_init(void)
  {
  	struct kmem_cache *s;
  	int err;
  
  	down_write(&slub_lock);
  
  	slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
  	if (!slab_kset) {
  		up_write(&slub_lock);
  		printk(KERN_ERR "Cannot register slab subsystem.\n");
  		return -ENOSYS;
  	}
  
  	slab_state = SYSFS;
  
  	list_for_each_entry(s, &slab_caches, list) {
  		err = sysfs_slab_add(s);
  		if (err)
  			printk(KERN_ERR "SLUB: Unable to add boot slab %s"
  						" to sysfs\n", s->name);
  	}
  
  	while (alias_list) {
  		struct saved_alias *al = alias_list;
  
  		alias_list = alias_list->next;
  		err = sysfs_slab_alias(al->s, al->name);
  		if (err)
  			printk(KERN_ERR "SLUB: Unable to add boot slab alias"
  					" %s to sysfs\n", s->name);
  		kfree(al);
  	}
  
  	up_write(&slub_lock);
  	resiliency_test();
  	return 0;
  }
  
  __initcall(slab_sysfs_init);
  #endif /* CONFIG_SYSFS */
  
  /*
   * The /proc/slabinfo ABI
   */
  #ifdef CONFIG_SLABINFO
  static void print_slabinfo_header(struct seq_file *m)
  {
  	seq_puts(m, "slabinfo - version: 2.1\n");
  	seq_puts(m, "# name            <active_objs> <num_objs> <objsize> "
  		 "<objperslab> <pagesperslab>");
  	seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
  	seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
  	seq_putc(m, '\n');
  }
  
  static void *s_start(struct seq_file *m, loff_t *pos)
  {
  	loff_t n = *pos;
  
  	down_read(&slub_lock);
  	if (!n)
  		print_slabinfo_header(m);
  
  	return seq_list_start(&slab_caches, *pos);
  }
  
  static void *s_next(struct seq_file *m, void *p, loff_t *pos)
  {
  	return seq_list_next(p, &slab_caches, pos);
  }
  
  static void s_stop(struct seq_file *m, void *p)
  {
  	up_read(&slub_lock);
  }
  
  static int s_show(struct seq_file *m, void *p)
  {
  	unsigned long nr_partials = 0;
  	unsigned long nr_slabs = 0;
  	unsigned long nr_inuse = 0;
  	unsigned long nr_objs = 0;
  	unsigned long nr_free = 0;
  	struct kmem_cache *s;
  	int node;
  
  	s = list_entry(p, struct kmem_cache, list);
  
  	for_each_online_node(node) {
  		struct kmem_cache_node *n = get_node(s, node);
  
  		if (!n)
  			continue;
  
  		nr_partials += n->nr_partial;
  		nr_slabs += atomic_long_read(&n->nr_slabs);
  		nr_objs += atomic_long_read(&n->total_objects);
  		nr_free += count_partial(n, count_free);
  	}
  
  	nr_inuse = nr_objs - nr_free;
  
  	seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
  		   nr_objs, s->size, oo_objects(s->oo),
  		   (1 << oo_order(s->oo)));
  	seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
  	seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
  		   0UL);
  	seq_putc(m, '\n');
  	return 0;
  }
  
  static const struct seq_operations slabinfo_op = {
  	.start = s_start,
  	.next = s_next,
  	.stop = s_stop,
  	.show = s_show,
  };
  
  static int slabinfo_open(struct inode *inode, struct file *file)
  {
  	return seq_open(file, &slabinfo_op);
  }
  
  static const struct file_operations proc_slabinfo_operations = {
  	.open		= slabinfo_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release,
  };
  
  static int __init slab_proc_init(void)
  {
  	proc_create("slabinfo", S_IRUGO, NULL, &proc_slabinfo_operations);
  	return 0;
  }
  module_init(slab_proc_init);
  #endif /* CONFIG_SLABINFO */
  