linux/mm/slab.c
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   1/*
   2 * linux/mm/slab.c
   3 * Written by Mark Hemment, 1996/97.
   4 * (markhe@nextd.demon.co.uk)
   5 *
   6 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
   7 *
   8 * Major cleanup, different bufctl logic, per-cpu arrays
   9 *      (c) 2000 Manfred Spraul
  10 *
  11 * Cleanup, make the head arrays unconditional, preparation for NUMA
  12 *      (c) 2002 Manfred Spraul
  13 *
  14 * An implementation of the Slab Allocator as described in outline in;
  15 *      UNIX Internals: The New Frontiers by Uresh Vahalia
  16 *      Pub: Prentice Hall      ISBN 0-13-101908-2
  17 * or with a little more detail in;
  18 *      The Slab Allocator: An Object-Caching Kernel Memory Allocator
  19 *      Jeff Bonwick (Sun Microsystems).
  20 *      Presented at: USENIX Summer 1994 Technical Conference
  21 *
  22 * The memory is organized in caches, one cache for each object type.
  23 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
  24 * Each cache consists out of many slabs (they are small (usually one
  25 * page long) and always contiguous), and each slab contains multiple
  26 * initialized objects.
  27 *
  28 * This means, that your constructor is used only for newly allocated
  29 * slabs and you must pass objects with the same initializations to
  30 * kmem_cache_free.
  31 *
  32 * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
  33 * normal). If you need a special memory type, then must create a new
  34 * cache for that memory type.
  35 *
  36 * In order to reduce fragmentation, the slabs are sorted in 3 groups:
  37 *   full slabs with 0 free objects
  38 *   partial slabs
  39 *   empty slabs with no allocated objects
  40 *
  41 * If partial slabs exist, then new allocations come from these slabs,
  42 * otherwise from empty slabs or new slabs are allocated.
  43 *
  44 * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
  45 * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
  46 *
  47 * Each cache has a short per-cpu head array, most allocs
  48 * and frees go into that array, and if that array overflows, then 1/2
  49 * of the entries in the array are given back into the global cache.
  50 * The head array is strictly LIFO and should improve the cache hit rates.
  51 * On SMP, it additionally reduces the spinlock operations.
  52 *
  53 * The c_cpuarray may not be read with enabled local interrupts -
  54 * it's changed with a smp_call_function().
  55 *
  56 * SMP synchronization:
  57 *  constructors and destructors are called without any locking.
  58 *  Several members in struct kmem_cache and struct slab never change, they
  59 *      are accessed without any locking.
  60 *  The per-cpu arrays are never accessed from the wrong cpu, no locking,
  61 *      and local interrupts are disabled so slab code is preempt-safe.
  62 *  The non-constant members are protected with a per-cache irq spinlock.
  63 *
  64 * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
  65 * in 2000 - many ideas in the current implementation are derived from
  66 * his patch.
  67 *
  68 * Further notes from the original documentation:
  69 *
  70 * 11 April '97.  Started multi-threading - markhe
  71 *      The global cache-chain is protected by the mutex 'cache_chain_mutex'.
  72 *      The sem is only needed when accessing/extending the cache-chain, which
  73 *      can never happen inside an interrupt (kmem_cache_create(),
  74 *      kmem_cache_shrink() and kmem_cache_reap()).
  75 *
  76 *      At present, each engine can be growing a cache.  This should be blocked.
  77 *
  78 * 15 March 2005. NUMA slab allocator.
  79 *      Shai Fultheim <shai@scalex86.org>.
  80 *      Shobhit Dayal <shobhit@calsoftinc.com>
  81 *      Alok N Kataria <alokk@calsoftinc.com>
  82 *      Christoph Lameter <christoph@lameter.com>
  83 *
  84 *      Modified the slab allocator to be node aware on NUMA systems.
  85 *      Each node has its own list of partial, free and full slabs.
  86 *      All object allocations for a node occur from node specific slab lists.
  87 */
  88
  89#include        <linux/slab.h>
  90#include        <linux/mm.h>
  91#include        <linux/poison.h>
  92#include        <linux/swap.h>
  93#include        <linux/cache.h>
  94#include        <linux/interrupt.h>
  95#include        <linux/init.h>
  96#include        <linux/compiler.h>
  97#include        <linux/cpuset.h>
  98#include        <linux/proc_fs.h>
  99#include        <linux/seq_file.h>
 100#include        <linux/notifier.h>
 101#include        <linux/kallsyms.h>
 102#include        <linux/cpu.h>
 103#include        <linux/sysctl.h>
 104#include        <linux/module.h>
 105#include        <linux/rcupdate.h>
 106#include        <linux/string.h>
 107#include        <linux/uaccess.h>
 108#include        <linux/nodemask.h>
 109#include        <linux/kmemleak.h>
 110#include        <linux/mempolicy.h>
 111#include        <linux/mutex.h>
 112#include        <linux/fault-inject.h>
 113#include        <linux/rtmutex.h>
 114#include        <linux/reciprocal_div.h>
 115#include        <linux/debugobjects.h>
 116#include        <linux/kmemcheck.h>
 117#include        <linux/memory.h>
 118#include        <linux/prefetch.h>
 119
 120#include        <asm/cacheflush.h>
 121#include        <asm/tlbflush.h>
 122#include        <asm/page.h>
 123
 124#include <trace/events/kmem.h>
 125
 126/*
 127 * DEBUG        - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
 128 *                0 for faster, smaller code (especially in the critical paths).
 129 *
 130 * STATS        - 1 to collect stats for /proc/slabinfo.
 131 *                0 for faster, smaller code (especially in the critical paths).
 132 *
 133 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
 134 */
 135
 136#ifdef CONFIG_DEBUG_SLAB
 137#define DEBUG           1
 138#define STATS           1
 139#define FORCED_DEBUG    1
 140#else
 141#define DEBUG           0
 142#define STATS           0
 143#define FORCED_DEBUG    0
 144#endif
 145
 146/* Shouldn't this be in a header file somewhere? */
 147#define BYTES_PER_WORD          sizeof(void *)
 148#define REDZONE_ALIGN           max(BYTES_PER_WORD, __alignof__(unsigned long long))
 149
 150#ifndef ARCH_KMALLOC_FLAGS
 151#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
 152#endif
 153
 154/* Legal flag mask for kmem_cache_create(). */
 155#if DEBUG
 156# define CREATE_MASK    (SLAB_RED_ZONE | \
 157                         SLAB_POISON | SLAB_HWCACHE_ALIGN | \
 158                         SLAB_CACHE_DMA | \
 159                         SLAB_STORE_USER | \
 160                         SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
 161                         SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
 162                         SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
 163#else
 164# define CREATE_MASK    (SLAB_HWCACHE_ALIGN | \
 165                         SLAB_CACHE_DMA | \
 166                         SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
 167                         SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
 168                         SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
 169#endif
 170
 171/*
 172 * kmem_bufctl_t:
 173 *
 174 * Bufctl's are used for linking objs within a slab
 175 * linked offsets.
 176 *
 177 * This implementation relies on "struct page" for locating the cache &
 178 * slab an object belongs to.
 179 * This allows the bufctl structure to be small (one int), but limits
 180 * the number of objects a slab (not a cache) can contain when off-slab
 181 * bufctls are used. The limit is the size of the largest general cache
 182 * that does not use off-slab slabs.
 183 * For 32bit archs with 4 kB pages, is this 56.
 184 * This is not serious, as it is only for large objects, when it is unwise
 185 * to have too many per slab.
 186 * Note: This limit can be raised by introducing a general cache whose size
 187 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
 188 */
 189
 190typedef unsigned int kmem_bufctl_t;
 191#define BUFCTL_END      (((kmem_bufctl_t)(~0U))-0)
 192#define BUFCTL_FREE     (((kmem_bufctl_t)(~0U))-1)
 193#define BUFCTL_ACTIVE   (((kmem_bufctl_t)(~0U))-2)
 194#define SLAB_LIMIT      (((kmem_bufctl_t)(~0U))-3)
 195
 196/*
 197 * struct slab_rcu
 198 *
 199 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
 200 * arrange for kmem_freepages to be called via RCU.  This is useful if
 201 * we need to approach a kernel structure obliquely, from its address
 202 * obtained without the usual locking.  We can lock the structure to
 203 * stabilize it and check it's still at the given address, only if we
 204 * can be sure that the memory has not been meanwhile reused for some
 205 * other kind of object (which our subsystem's lock might corrupt).
 206 *
 207 * rcu_read_lock before reading the address, then rcu_read_unlock after
 208 * taking the spinlock within the structure expected at that address.
 209 */
 210struct slab_rcu {
 211        struct rcu_head head;
 212        struct kmem_cache *cachep;
 213        void *addr;
 214};
 215
 216/*
 217 * struct slab
 218 *
 219 * Manages the objs in a slab. Placed either at the beginning of mem allocated
 220 * for a slab, or allocated from an general cache.
 221 * Slabs are chained into three list: fully used, partial, fully free slabs.
 222 */
 223struct slab {
 224        union {
 225                struct {
 226                        struct list_head list;
 227                        unsigned long colouroff;
 228                        void *s_mem;            /* including colour offset */
 229                        unsigned int inuse;     /* num of objs active in slab */
 230                        kmem_bufctl_t free;
 231                        unsigned short nodeid;
 232                };
 233                struct slab_rcu __slab_cover_slab_rcu;
 234        };
 235};
 236
 237/*
 238 * struct array_cache
 239 *
 240 * Purpose:
 241 * - LIFO ordering, to hand out cache-warm objects from _alloc
 242 * - reduce the number of linked list operations
 243 * - reduce spinlock operations
 244 *
 245 * The limit is stored in the per-cpu structure to reduce the data cache
 246 * footprint.
 247 *
 248 */
 249struct array_cache {
 250        unsigned int avail;
 251        unsigned int limit;
 252        unsigned int batchcount;
 253        unsigned int touched;
 254        spinlock_t lock;
 255        void *entry[];  /*
 256                         * Must have this definition in here for the proper
 257                         * alignment of array_cache. Also simplifies accessing
 258                         * the entries.
 259                         */
 260};
 261
 262/*
 263 * bootstrap: The caches do not work without cpuarrays anymore, but the
 264 * cpuarrays are allocated from the generic caches...
 265 */
 266#define BOOT_CPUCACHE_ENTRIES   1
 267struct arraycache_init {
 268        struct array_cache cache;
 269        void *entries[BOOT_CPUCACHE_ENTRIES];
 270};
 271
 272/*
 273 * The slab lists for all objects.
 274 */
 275struct kmem_list3 {
 276        struct list_head slabs_partial; /* partial list first, better asm code */
 277        struct list_head slabs_full;
 278        struct list_head slabs_free;
 279        unsigned long free_objects;
 280        unsigned int free_limit;
 281        unsigned int colour_next;       /* Per-node cache coloring */
 282        spinlock_t list_lock;
 283        struct array_cache *shared;     /* shared per node */
 284        struct array_cache **alien;     /* on other nodes */
 285        unsigned long next_reap;        /* updated without locking */
 286        int free_touched;               /* updated without locking */
 287};
 288
 289/*
 290 * Need this for bootstrapping a per node allocator.
 291 */
 292#define NUM_INIT_LISTS (3 * MAX_NUMNODES)
 293static struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
 294#define CACHE_CACHE 0
 295#define SIZE_AC MAX_NUMNODES
 296#define SIZE_L3 (2 * MAX_NUMNODES)
 297
 298static int drain_freelist(struct kmem_cache *cache,
 299                        struct kmem_list3 *l3, int tofree);
 300static void free_block(struct kmem_cache *cachep, void **objpp, int len,
 301                        int node);
 302static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
 303static void cache_reap(struct work_struct *unused);
 304
 305/*
 306 * This function must be completely optimized away if a constant is passed to
 307 * it.  Mostly the same as what is in linux/slab.h except it returns an index.
 308 */
 309static __always_inline int index_of(const size_t size)
 310{
 311        extern void __bad_size(void);
 312
 313        if (__builtin_constant_p(size)) {
 314                int i = 0;
 315
 316#define CACHE(x) \
 317        if (size <=x) \
 318                return i; \
 319        else \
 320                i++;
 321#include <linux/kmalloc_sizes.h>
 322#undef CACHE
 323                __bad_size();
 324        } else
 325                __bad_size();
 326        return 0;
 327}
 328
 329static int slab_early_init = 1;
 330
 331#define INDEX_AC index_of(sizeof(struct arraycache_init))
 332#define INDEX_L3 index_of(sizeof(struct kmem_list3))
 333
 334static void kmem_list3_init(struct kmem_list3 *parent)
 335{
 336        INIT_LIST_HEAD(&parent->slabs_full);
 337        INIT_LIST_HEAD(&parent->slabs_partial);
 338        INIT_LIST_HEAD(&parent->slabs_free);
 339        parent->shared = NULL;
 340        parent->alien = NULL;
 341        parent->colour_next = 0;
 342        spin_lock_init(&parent->list_lock);
 343        parent->free_objects = 0;
 344        parent->free_touched = 0;
 345}
 346
 347#define MAKE_LIST(cachep, listp, slab, nodeid)                          \
 348        do {                                                            \
 349                INIT_LIST_HEAD(listp);                                  \
 350                list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
 351        } while (0)
 352
 353#define MAKE_ALL_LISTS(cachep, ptr, nodeid)                             \
 354        do {                                                            \
 355        MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid);  \
 356        MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
 357        MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid);  \
 358        } while (0)
 359
 360#define CFLGS_OFF_SLAB          (0x80000000UL)
 361#define OFF_SLAB(x)     ((x)->flags & CFLGS_OFF_SLAB)
 362
 363#define BATCHREFILL_LIMIT       16
 364/*
 365 * Optimization question: fewer reaps means less probability for unnessary
 366 * cpucache drain/refill cycles.
 367 *
 368 * OTOH the cpuarrays can contain lots of objects,
 369 * which could lock up otherwise freeable slabs.
 370 */
 371#define REAPTIMEOUT_CPUC        (2*HZ)
 372#define REAPTIMEOUT_LIST3       (4*HZ)
 373
 374#if STATS
 375#define STATS_INC_ACTIVE(x)     ((x)->num_active++)
 376#define STATS_DEC_ACTIVE(x)     ((x)->num_active--)
 377#define STATS_INC_ALLOCED(x)    ((x)->num_allocations++)
 378#define STATS_INC_GROWN(x)      ((x)->grown++)
 379#define STATS_ADD_REAPED(x,y)   ((x)->reaped += (y))
 380#define STATS_SET_HIGH(x)                                               \
 381        do {                                                            \
 382                if ((x)->num_active > (x)->high_mark)                   \
 383                        (x)->high_mark = (x)->num_active;               \
 384        } while (0)
 385#define STATS_INC_ERR(x)        ((x)->errors++)
 386#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
 387#define STATS_INC_NODEFREES(x)  ((x)->node_frees++)
 388#define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
 389#define STATS_SET_FREEABLE(x, i)                                        \
 390        do {                                                            \
 391                if ((x)->max_freeable < i)                              \
 392                        (x)->max_freeable = i;                          \
 393        } while (0)
 394#define STATS_INC_ALLOCHIT(x)   atomic_inc(&(x)->allochit)
 395#define STATS_INC_ALLOCMISS(x)  atomic_inc(&(x)->allocmiss)
 396#define STATS_INC_FREEHIT(x)    atomic_inc(&(x)->freehit)
 397#define STATS_INC_FREEMISS(x)   atomic_inc(&(x)->freemiss)
 398#else
 399#define STATS_INC_ACTIVE(x)     do { } while (0)
 400#define STATS_DEC_ACTIVE(x)     do { } while (0)
 401#define STATS_INC_ALLOCED(x)    do { } while (0)
 402#define STATS_INC_GROWN(x)      do { } while (0)
 403#define STATS_ADD_REAPED(x,y)   do { (void)(y); } while (0)
 404#define STATS_SET_HIGH(x)       do { } while (0)
 405#define STATS_INC_ERR(x)        do { } while (0)
 406#define STATS_INC_NODEALLOCS(x) do { } while (0)
 407#define STATS_INC_NODEFREES(x)  do { } while (0)
 408#define STATS_INC_ACOVERFLOW(x)   do { } while (0)
 409#define STATS_SET_FREEABLE(x, i) do { } while (0)
 410#define STATS_INC_ALLOCHIT(x)   do { } while (0)
 411#define STATS_INC_ALLOCMISS(x)  do { } while (0)
 412#define STATS_INC_FREEHIT(x)    do { } while (0)
 413#define STATS_INC_FREEMISS(x)   do { } while (0)
 414#endif
 415
 416#if DEBUG
 417
 418/*
 419 * memory layout of objects:
 420 * 0            : objp
 421 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
 422 *              the end of an object is aligned with the end of the real
 423 *              allocation. Catches writes behind the end of the allocation.
 424 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
 425 *              redzone word.
 426 * cachep->obj_offset: The real object.
 427 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
 428 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
 429 *                                      [BYTES_PER_WORD long]
 430 */
 431static int obj_offset(struct kmem_cache *cachep)
 432{
 433        return cachep->obj_offset;
 434}
 435
 436static int obj_size(struct kmem_cache *cachep)
 437{
 438        return cachep->obj_size;
 439}
 440
 441static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
 442{
 443        BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
 444        return (unsigned long long*) (objp + obj_offset(cachep) -
 445                                      sizeof(unsigned long long));
 446}
 447
 448static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
 449{
 450        BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
 451        if (cachep->flags & SLAB_STORE_USER)
 452                return (unsigned long long *)(objp + cachep->buffer_size -
 453                                              sizeof(unsigned long long) -
 454                                              REDZONE_ALIGN);
 455        return (unsigned long long *) (objp + cachep->buffer_size -
 456                                       sizeof(unsigned long long));
 457}
 458
 459static void **dbg_userword(struct kmem_cache *cachep, void *objp)
 460{
 461        BUG_ON(!(cachep->flags & SLAB_STORE_USER));
 462        return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
 463}
 464
 465#else
 466
 467#define obj_offset(x)                   0
 468#define obj_size(cachep)                (cachep->buffer_size)
 469#define dbg_redzone1(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
 470#define dbg_redzone2(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
 471#define dbg_userword(cachep, objp)      ({BUG(); (void **)NULL;})
 472
 473#endif
 474
 475#ifdef CONFIG_TRACING
 476size_t slab_buffer_size(struct kmem_cache *cachep)
 477{
 478        return cachep->buffer_size;
 479}
 480EXPORT_SYMBOL(slab_buffer_size);
 481#endif
 482
 483/*
 484 * Do not go above this order unless 0 objects fit into the slab or
 485 * overridden on the command line.
 486 */
 487#define SLAB_MAX_ORDER_HI       1
 488#define SLAB_MAX_ORDER_LO       0
 489static int slab_max_order = SLAB_MAX_ORDER_LO;
 490static bool slab_max_order_set __initdata;
 491
 492/*
 493 * Functions for storing/retrieving the cachep and or slab from the page
 494 * allocator.  These are used to find the slab an obj belongs to.  With kfree(),
 495 * these are used to find the cache which an obj belongs to.
 496 */
 497static inline void page_set_cache(struct page *page, struct kmem_cache *cache)
 498{
 499        page->lru.next = (struct list_head *)cache;
 500}
 501
 502static inline struct kmem_cache *page_get_cache(struct page *page)
 503{
 504        page = compound_head(page);
 505        BUG_ON(!PageSlab(page));
 506        return (struct kmem_cache *)page->lru.next;
 507}
 508
 509static inline void page_set_slab(struct page *page, struct slab *slab)
 510{
 511        page->lru.prev = (struct list_head *)slab;
 512}
 513
 514static inline struct slab *page_get_slab(struct page *page)
 515{
 516        BUG_ON(!PageSlab(page));
 517        return (struct slab *)page->lru.prev;
 518}
 519
 520static inline struct kmem_cache *virt_to_cache(const void *obj)
 521{
 522        struct page *page = virt_to_head_page(obj);
 523        return page_get_cache(page);
 524}
 525
 526static inline struct slab *virt_to_slab(const void *obj)
 527{
 528        struct page *page = virt_to_head_page(obj);
 529        return page_get_slab(page);
 530}
 531
 532static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
 533                                 unsigned int idx)
 534{
 535        return slab->s_mem + cache->buffer_size * idx;
 536}
 537
 538/*
 539 * We want to avoid an expensive divide : (offset / cache->buffer_size)
 540 *   Using the fact that buffer_size is a constant for a particular cache,
 541 *   we can replace (offset / cache->buffer_size) by
 542 *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
 543 */
 544static inline unsigned int obj_to_index(const struct kmem_cache *cache,
 545                                        const struct slab *slab, void *obj)
 546{
 547        u32 offset = (obj - slab->s_mem);
 548        return reciprocal_divide(offset, cache->reciprocal_buffer_size);
 549}
 550
 551/*
 552 * These are the default caches for kmalloc. Custom caches can have other sizes.
 553 */
 554struct cache_sizes malloc_sizes[] = {
 555#define CACHE(x) { .cs_size = (x) },
 556#include <linux/kmalloc_sizes.h>
 557        CACHE(ULONG_MAX)
 558#undef CACHE
 559};
 560EXPORT_SYMBOL(malloc_sizes);
 561
 562/* Must match cache_sizes above. Out of line to keep cache footprint low. */
 563struct cache_names {
 564        char *name;
 565        char *name_dma;
 566};
 567
 568static struct cache_names __initdata cache_names[] = {
 569#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
 570#include <linux/kmalloc_sizes.h>
 571        {NULL,}
 572#undef CACHE
 573};
 574
 575static struct arraycache_init initarray_cache __initdata =
 576    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
 577static struct arraycache_init initarray_generic =
 578    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
 579
 580/* internal cache of cache description objs */
 581static struct kmem_list3 *cache_cache_nodelists[MAX_NUMNODES];
 582static struct kmem_cache cache_cache = {
 583        .nodelists = cache_cache_nodelists,
 584        .batchcount = 1,
 585        .limit = BOOT_CPUCACHE_ENTRIES,
 586        .shared = 1,
 587        .buffer_size = sizeof(struct kmem_cache),
 588        .name = "kmem_cache",
 589};
 590
 591#define BAD_ALIEN_MAGIC 0x01020304ul
 592
 593/*
 594 * chicken and egg problem: delay the per-cpu array allocation
 595 * until the general caches are up.
 596 */
 597static enum {
 598        NONE,
 599        PARTIAL_AC,
 600        PARTIAL_L3,
 601        EARLY,
 602        LATE,
 603        FULL
 604} g_cpucache_up;
 605
 606/*
 607 * used by boot code to determine if it can use slab based allocator
 608 */
 609int slab_is_available(void)
 610{
 611        return g_cpucache_up >= EARLY;
 612}
 613
 614#ifdef CONFIG_LOCKDEP
 615
 616/*
 617 * Slab sometimes uses the kmalloc slabs to store the slab headers
 618 * for other slabs "off slab".
 619 * The locking for this is tricky in that it nests within the locks
 620 * of all other slabs in a few places; to deal with this special
 621 * locking we put on-slab caches into a separate lock-class.
 622 *
 623 * We set lock class for alien array caches which are up during init.
 624 * The lock annotation will be lost if all cpus of a node goes down and
 625 * then comes back up during hotplug
 626 */
 627static struct lock_class_key on_slab_l3_key;
 628static struct lock_class_key on_slab_alc_key;
 629
 630static struct lock_class_key debugobj_l3_key;
 631static struct lock_class_key debugobj_alc_key;
 632
 633static void slab_set_lock_classes(struct kmem_cache *cachep,
 634                struct lock_class_key *l3_key, struct lock_class_key *alc_key,
 635                int q)
 636{
 637        struct array_cache **alc;
 638        struct kmem_list3 *l3;
 639        int r;
 640
 641        l3 = cachep->nodelists[q];
 642        if (!l3)
 643                return;
 644
 645        lockdep_set_class(&l3->list_lock, l3_key);
 646        alc = l3->alien;
 647        /*
 648         * FIXME: This check for BAD_ALIEN_MAGIC
 649         * should go away when common slab code is taught to
 650         * work even without alien caches.
 651         * Currently, non NUMA code returns BAD_ALIEN_MAGIC
 652         * for alloc_alien_cache,
 653         */
 654        if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
 655                return;
 656        for_each_node(r) {
 657                if (alc[r])
 658                        lockdep_set_class(&alc[r]->lock, alc_key);
 659        }
 660}
 661
 662static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
 663{
 664        slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node);
 665}
 666
 667static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
 668{
 669        int node;
 670
 671        for_each_online_node(node)
 672                slab_set_debugobj_lock_classes_node(cachep, node);
 673}
 674
 675static void init_node_lock_keys(int q)
 676{
 677        struct cache_sizes *s = malloc_sizes;
 678
 679        if (g_cpucache_up < LATE)
 680                return;
 681
 682        for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
 683                struct kmem_list3 *l3;
 684
 685                l3 = s->cs_cachep->nodelists[q];
 686                if (!l3 || OFF_SLAB(s->cs_cachep))
 687                        continue;
 688
 689                slab_set_lock_classes(s->cs_cachep, &on_slab_l3_key,
 690                                &on_slab_alc_key, q);
 691        }
 692}
 693
 694static inline void init_lock_keys(void)
 695{
 696        int node;
 697
 698        for_each_node(node)
 699                init_node_lock_keys(node);
 700}
 701#else
 702static void init_node_lock_keys(int q)
 703{
 704}
 705
 706static inline void init_lock_keys(void)
 707{
 708}
 709
 710static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
 711{
 712}
 713
 714static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
 715{
 716}
 717#endif
 718
 719/*
 720 * Guard access to the cache-chain.
 721 */
 722static DEFINE_MUTEX(cache_chain_mutex);
 723static struct list_head cache_chain;
 724
 725static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
 726
 727static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
 728{
 729        return cachep->array[smp_processor_id()];
 730}
 731
 732static inline struct kmem_cache *__find_general_cachep(size_t size,
 733                                                        gfp_t gfpflags)
 734{
 735        struct cache_sizes *csizep = malloc_sizes;
 736
 737#if DEBUG
 738        /* This happens if someone tries to call
 739         * kmem_cache_create(), or __kmalloc(), before
 740         * the generic caches are initialized.
 741         */
 742        BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
 743#endif
 744        if (!size)
 745                return ZERO_SIZE_PTR;
 746
 747        while (size > csizep->cs_size)
 748                csizep++;
 749
 750        /*
 751         * Really subtle: The last entry with cs->cs_size==ULONG_MAX
 752         * has cs_{dma,}cachep==NULL. Thus no special case
 753         * for large kmalloc calls required.
 754         */
 755#ifdef CONFIG_ZONE_DMA
 756        if (unlikely(gfpflags & GFP_DMA))
 757                return csizep->cs_dmacachep;
 758#endif
 759        return csizep->cs_cachep;
 760}
 761
 762static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
 763{
 764        return __find_general_cachep(size, gfpflags);
 765}
 766
 767static size_t slab_mgmt_size(size_t nr_objs, size_t align)
 768{
 769        return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
 770}
 771
 772/*
 773 * Calculate the number of objects and left-over bytes for a given buffer size.
 774 */
 775static void cache_estimate(unsigned long gfporder, size_t buffer_size,
 776                           size_t align, int flags, size_t *left_over,
 777                           unsigned int *num)
 778{
 779        int nr_objs;
 780        size_t mgmt_size;
 781        size_t slab_size = PAGE_SIZE << gfporder;
 782
 783        /*
 784         * The slab management structure can be either off the slab or
 785         * on it. For the latter case, the memory allocated for a
 786         * slab is used for:
 787         *
 788         * - The struct slab
 789         * - One kmem_bufctl_t for each object
 790         * - Padding to respect alignment of @align
 791         * - @buffer_size bytes for each object
 792         *
 793         * If the slab management structure is off the slab, then the
 794         * alignment will already be calculated into the size. Because
 795         * the slabs are all pages aligned, the objects will be at the
 796         * correct alignment when allocated.
 797         */
 798        if (flags & CFLGS_OFF_SLAB) {
 799                mgmt_size = 0;
 800                nr_objs = slab_size / buffer_size;
 801
 802                if (nr_objs > SLAB_LIMIT)
 803                        nr_objs = SLAB_LIMIT;
 804        } else {
 805                /*
 806                 * Ignore padding for the initial guess. The padding
 807                 * is at most @align-1 bytes, and @buffer_size is at
 808                 * least @align. In the worst case, this result will
 809                 * be one greater than the number of objects that fit
 810                 * into the memory allocation when taking the padding
 811                 * into account.
 812                 */
 813                nr_objs = (slab_size - sizeof(struct slab)) /
 814                          (buffer_size + sizeof(kmem_bufctl_t));
 815
 816                /*
 817                 * This calculated number will be either the right
 818                 * amount, or one greater than what we want.
 819                 */
 820                if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
 821                       > slab_size)
 822                        nr_objs--;
 823
 824                if (nr_objs > SLAB_LIMIT)
 825                        nr_objs = SLAB_LIMIT;
 826
 827                mgmt_size = slab_mgmt_size(nr_objs, align);
 828        }
 829        *num = nr_objs;
 830        *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
 831}
 832
 833#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
 834
 835static void __slab_error(const char *function, struct kmem_cache *cachep,
 836                        char *msg)
 837{
 838        printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
 839               function, cachep->name, msg);
 840        dump_stack();
 841}
 842
 843/*
 844 * By default on NUMA we use alien caches to stage the freeing of
 845 * objects allocated from other nodes. This causes massive memory
 846 * inefficiencies when using fake NUMA setup to split memory into a
 847 * large number of small nodes, so it can be disabled on the command
 848 * line
 849  */
 850
 851static int use_alien_caches __read_mostly = 1;
 852static int __init noaliencache_setup(char *s)
 853{
 854        use_alien_caches = 0;
 855        return 1;
 856}
 857__setup("noaliencache", noaliencache_setup);
 858
 859static int __init slab_max_order_setup(char *str)
 860{
 861        get_option(&str, &slab_max_order);
 862        slab_max_order = slab_max_order < 0 ? 0 :
 863                                min(slab_max_order, MAX_ORDER - 1);
 864        slab_max_order_set = true;
 865
 866        return 1;
 867}
 868__setup("slab_max_order=", slab_max_order_setup);
 869
 870#ifdef CONFIG_NUMA
 871/*
 872 * Special reaping functions for NUMA systems called from cache_reap().
 873 * These take care of doing round robin flushing of alien caches (containing
 874 * objects freed on different nodes from which they were allocated) and the
 875 * flushing of remote pcps by calling drain_node_pages.
 876 */
 877static DEFINE_PER_CPU(unsigned long, slab_reap_node);
 878
 879static void init_reap_node(int cpu)
 880{
 881        int node;
 882
 883        node = next_node(cpu_to_mem(cpu), node_online_map);
 884        if (node == MAX_NUMNODES)
 885                node = first_node(node_online_map);
 886
 887        per_cpu(slab_reap_node, cpu) = node;
 888}
 889
 890static void next_reap_node(void)
 891{
 892        int node = __this_cpu_read(slab_reap_node);
 893
 894        node = next_node(node, node_online_map);
 895        if (unlikely(node >= MAX_NUMNODES))
 896                node = first_node(node_online_map);
 897        __this_cpu_write(slab_reap_node, node);
 898}
 899
 900#else
 901#define init_reap_node(cpu) do { } while (0)
 902#define next_reap_node(void) do { } while (0)
 903#endif
 904
 905/*
 906 * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
 907 * via the workqueue/eventd.
 908 * Add the CPU number into the expiration time to minimize the possibility of
 909 * the CPUs getting into lockstep and contending for the global cache chain
 910 * lock.
 911 */
 912static void __cpuinit start_cpu_timer(int cpu)
 913{
 914        struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
 915
 916        /*
 917         * When this gets called from do_initcalls via cpucache_init(),
 918         * init_workqueues() has already run, so keventd will be setup
 919         * at that time.
 920         */
 921        if (keventd_up() && reap_work->work.func == NULL) {
 922                init_reap_node(cpu);
 923                INIT_DELAYED_WORK_DEFERRABLE(reap_work, cache_reap);
 924                schedule_delayed_work_on(cpu, reap_work,
 925                                        __round_jiffies_relative(HZ, cpu));
 926        }
 927}
 928
 929static struct array_cache *alloc_arraycache(int node, int entries,
 930                                            int batchcount, gfp_t gfp)
 931{
 932        int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
 933        struct array_cache *nc = NULL;
 934
 935        nc = kmalloc_node(memsize, gfp, node);
 936        /*
 937         * The array_cache structures contain pointers to free object.
 938         * However, when such objects are allocated or transferred to another
 939         * cache the pointers are not cleared and they could be counted as
 940         * valid references during a kmemleak scan. Therefore, kmemleak must
 941         * not scan such objects.
 942         */
 943        kmemleak_no_scan(nc);
 944        if (nc) {
 945                nc->avail = 0;
 946                nc->limit = entries;
 947                nc->batchcount = batchcount;
 948                nc->touched = 0;
 949                spin_lock_init(&nc->lock);
 950        }
 951        return nc;
 952}
 953
 954/*
 955 * Transfer objects in one arraycache to another.
 956 * Locking must be handled by the caller.
 957 *
 958 * Return the number of entries transferred.
 959 */
 960static int transfer_objects(struct array_cache *to,
 961                struct array_cache *from, unsigned int max)
 962{
 963        /* Figure out how many entries to transfer */
 964        int nr = min3(from->avail, max, to->limit - to->avail);
 965
 966        if (!nr)
 967                return 0;
 968
 969        memcpy(to->entry + to->avail, from->entry + from->avail -nr,
 970                        sizeof(void *) *nr);
 971
 972        from->avail -= nr;
 973        to->avail += nr;
 974        return nr;
 975}
 976
 977#ifndef CONFIG_NUMA
 978
 979#define drain_alien_cache(cachep, alien) do { } while (0)
 980#define reap_alien(cachep, l3) do { } while (0)
 981
 982static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
 983{
 984        return (struct array_cache **)BAD_ALIEN_MAGIC;
 985}
 986
 987static inline void free_alien_cache(struct array_cache **ac_ptr)
 988{
 989}
 990
 991static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
 992{
 993        return 0;
 994}
 995
 996static inline void *alternate_node_alloc(struct kmem_cache *cachep,
 997                gfp_t flags)
 998{
 999        return NULL;
1000}
1001
1002static inline void *____cache_alloc_node(struct kmem_cache *cachep,
1003                 gfp_t flags, int nodeid)
1004{
1005        return NULL;
1006}
1007
1008#else   /* CONFIG_NUMA */
1009
1010static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
1011static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
1012
1013static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
1014{
1015        struct array_cache **ac_ptr;
1016        int memsize = sizeof(void *) * nr_node_ids;
1017        int i;
1018
1019        if (limit > 1)
1020                limit = 12;
1021        ac_ptr = kzalloc_node(memsize, gfp, node);
1022        if (ac_ptr) {
1023                for_each_node(i) {
1024                        if (i == node || !node_online(i))
1025                                continue;
1026                        ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
1027                        if (!ac_ptr[i]) {
1028                                for (i--; i >= 0; i--)
1029                                        kfree(ac_ptr[i]);
1030                                kfree(ac_ptr);
1031                                return NULL;
1032                        }
1033                }
1034        }
1035        return ac_ptr;
1036}
1037
1038static void free_alien_cache(struct array_cache **ac_ptr)
1039{
1040        int i;
1041
1042        if (!ac_ptr)
1043                return;
1044        for_each_node(i)
1045            kfree(ac_ptr[i]);
1046        kfree(ac_ptr);
1047}
1048
1049static void __drain_alien_cache(struct kmem_cache *cachep,
1050                                struct array_cache *ac, int node)
1051{
1052        struct kmem_list3 *rl3 = cachep->nodelists[node];
1053
1054        if (ac->avail) {
1055                spin_lock(&rl3->list_lock);
1056                /*
1057                 * Stuff objects into the remote nodes shared array first.
1058                 * That way we could avoid the overhead of putting the objects
1059                 * into the free lists and getting them back later.
1060                 */
1061                if (rl3->shared)
1062                        transfer_objects(rl3->shared, ac, ac->limit);
1063
1064                free_block(cachep, ac->entry, ac->avail, node);
1065                ac->avail = 0;
1066                spin_unlock(&rl3->list_lock);
1067        }
1068}
1069
1070/*
1071 * Called from cache_reap() to regularly drain alien caches round robin.
1072 */
1073static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
1074{
1075        int node = __this_cpu_read(slab_reap_node);
1076
1077        if (l3->alien) {
1078                struct array_cache *ac = l3->alien[node];
1079
1080                if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1081                        __drain_alien_cache(cachep, ac, node);
1082                        spin_unlock_irq(&ac->lock);
1083                }
1084        }
1085}
1086
1087static void drain_alien_cache(struct kmem_cache *cachep,
1088                                struct array_cache **alien)
1089{
1090        int i = 0;
1091        struct array_cache *ac;
1092        unsigned long flags;
1093
1094        for_each_online_node(i) {
1095                ac = alien[i];
1096                if (ac) {
1097                        spin_lock_irqsave(&ac->lock, flags);
1098                        __drain_alien_cache(cachep, ac, i);
1099                        spin_unlock_irqrestore(&ac->lock, flags);
1100                }
1101        }
1102}
1103
1104static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1105{
1106        struct slab *slabp = virt_to_slab(objp);
1107        int nodeid = slabp->nodeid;
1108        struct kmem_list3 *l3;
1109        struct array_cache *alien = NULL;
1110        int node;
1111
1112        node = numa_mem_id();
1113
1114        /*
1115         * Make sure we are not freeing a object from another node to the array
1116         * cache on this cpu.
1117         */
1118        if (likely(slabp->nodeid == node))
1119                return 0;
1120
1121        l3 = cachep->nodelists[node];
1122        STATS_INC_NODEFREES(cachep);
1123        if (l3->alien && l3->alien[nodeid]) {
1124                alien = l3->alien[nodeid];
1125                spin_lock(&alien->lock);
1126                if (unlikely(alien->avail == alien->limit)) {
1127                        STATS_INC_ACOVERFLOW(cachep);
1128                        __drain_alien_cache(cachep, alien, nodeid);
1129                }
1130                alien->entry[alien->avail++] = objp;
1131                spin_unlock(&alien->lock);
1132        } else {
1133                spin_lock(&(cachep->nodelists[nodeid])->list_lock);
1134                free_block(cachep, &objp, 1, nodeid);
1135                spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
1136        }
1137        return 1;
1138}
1139#endif
1140
1141/*
1142 * Allocates and initializes nodelists for a node on each slab cache, used for
1143 * either memory or cpu hotplug.  If memory is being hot-added, the kmem_list3
1144 * will be allocated off-node since memory is not yet online for the new node.
1145 * When hotplugging memory or a cpu, existing nodelists are not replaced if
1146 * already in use.
1147 *
1148 * Must hold cache_chain_mutex.
1149 */
1150static int init_cache_nodelists_node(int node)
1151{
1152        struct kmem_cache *cachep;
1153        struct kmem_list3 *l3;
1154        const int memsize = sizeof(struct kmem_list3);
1155
1156        list_for_each_entry(cachep, &cache_chain, next) {
1157                /*
1158                 * Set up the size64 kmemlist for cpu before we can
1159                 * begin anything. Make sure some other cpu on this
1160                 * node has not already allocated this
1161                 */
1162                if (!cachep->nodelists[node]) {
1163                        l3 = kmalloc_node(memsize, GFP_KERNEL, node);
1164                        if (!l3)
1165                                return -ENOMEM;
1166                        kmem_list3_init(l3);
1167                        l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1168                            ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1169
1170                        /*
1171                         * The l3s don't come and go as CPUs come and
1172                         * go.  cache_chain_mutex is sufficient
1173                         * protection here.
1174                         */
1175                        cachep->nodelists[node] = l3;
1176                }
1177
1178                spin_lock_irq(&cachep->nodelists[node]->list_lock);
1179                cachep->nodelists[node]->free_limit =
1180                        (1 + nr_cpus_node(node)) *
1181                        cachep->batchcount + cachep->num;
1182                spin_unlock_irq(&cachep->nodelists[node]->list_lock);
1183        }
1184        return 0;
1185}
1186
1187static void __cpuinit cpuup_canceled(long cpu)
1188{
1189        struct kmem_cache *cachep;
1190        struct kmem_list3 *l3 = NULL;
1191        int node = cpu_to_mem(cpu);
1192        const struct cpumask *mask = cpumask_of_node(node);
1193
1194        list_for_each_entry(cachep, &cache_chain, next) {
1195                struct array_cache *nc;
1196                struct array_cache *shared;
1197                struct array_cache **alien;
1198
1199                /* cpu is dead; no one can alloc from it. */
1200                nc = cachep->array[cpu];
1201                cachep->array[cpu] = NULL;
1202                l3 = cachep->nodelists[node];
1203
1204                if (!l3)
1205                        goto free_array_cache;
1206
1207                spin_lock_irq(&l3->list_lock);
1208
1209                /* Free limit for this kmem_list3 */
1210                l3->free_limit -= cachep->batchcount;
1211                if (nc)
1212                        free_block(cachep, nc->entry, nc->avail, node);
1213
1214                if (!cpumask_empty(mask)) {
1215                        spin_unlock_irq(&l3->list_lock);
1216                        goto free_array_cache;
1217                }
1218
1219                shared = l3->shared;
1220                if (shared) {
1221                        free_block(cachep, shared->entry,
1222                                   shared->avail, node);
1223                        l3->shared = NULL;
1224                }
1225
1226                alien = l3->alien;
1227                l3->alien = NULL;
1228
1229                spin_unlock_irq(&l3->list_lock);
1230
1231                kfree(shared);
1232                if (alien) {
1233                        drain_alien_cache(cachep, alien);
1234                        free_alien_cache(alien);
1235                }
1236free_array_cache:
1237                kfree(nc);
1238        }
1239        /*
1240         * In the previous loop, all the objects were freed to
1241         * the respective cache's slabs,  now we can go ahead and
1242         * shrink each nodelist to its limit.
1243         */
1244        list_for_each_entry(cachep, &cache_chain, next) {
1245                l3 = cachep->nodelists[node];
1246                if (!l3)
1247                        continue;
1248                drain_freelist(cachep, l3, l3->free_objects);
1249        }
1250}
1251
1252static int __cpuinit cpuup_prepare(long cpu)
1253{
1254        struct kmem_cache *cachep;
1255        struct kmem_list3 *l3 = NULL;
1256        int node = cpu_to_mem(cpu);
1257        int err;
1258
1259        /*
1260         * We need to do this right in the beginning since
1261         * alloc_arraycache's are going to use this list.
1262         * kmalloc_node allows us to add the slab to the right
1263         * kmem_list3 and not this cpu's kmem_list3
1264         */
1265        err = init_cache_nodelists_node(node);
1266        if (err < 0)
1267                goto bad;
1268
1269        /*
1270         * Now we can go ahead with allocating the shared arrays and
1271         * array caches
1272         */
1273        list_for_each_entry(cachep, &cache_chain, next) {
1274                struct array_cache *nc;
1275                struct array_cache *shared = NULL;
1276                struct array_cache **alien = NULL;
1277
1278                nc = alloc_arraycache(node, cachep->limit,
1279                                        cachep->batchcount, GFP_KERNEL);
1280                if (!nc)
1281                        goto bad;
1282                if (cachep->shared) {
1283                        shared = alloc_arraycache(node,
1284                                cachep->shared * cachep->batchcount,
1285                                0xbaadf00d, GFP_KERNEL);
1286                        if (!shared) {
1287                                kfree(nc);
1288                                goto bad;
1289                        }
1290                }
1291                if (use_alien_caches) {
1292                        alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
1293                        if (!alien) {
1294                                kfree(shared);
1295                                kfree(nc);
1296                                goto bad;
1297                        }
1298                }
1299                cachep->array[cpu] = nc;
1300                l3 = cachep->nodelists[node];
1301                BUG_ON(!l3);
1302
1303                spin_lock_irq(&l3->list_lock);
1304                if (!l3->shared) {
1305                        /*
1306                         * We are serialised from CPU_DEAD or
1307                         * CPU_UP_CANCELLED by the cpucontrol lock
1308                         */
1309                        l3->shared = shared;
1310                        shared = NULL;
1311                }
1312#ifdef CONFIG_NUMA
1313                if (!l3->alien) {
1314                        l3->alien = alien;
1315                        alien = NULL;
1316                }
1317#endif
1318                spin_unlock_irq(&l3->list_lock);
1319                kfree(shared);
1320                free_alien_cache(alien);
1321                if (cachep->flags & SLAB_DEBUG_OBJECTS)
1322                        slab_set_debugobj_lock_classes_node(cachep, node);
1323        }
1324        init_node_lock_keys(node);
1325
1326        return 0;
1327bad:
1328        cpuup_canceled(cpu);
1329        return -ENOMEM;
1330}
1331
1332static int __cpuinit cpuup_callback(struct notifier_block *nfb,
1333                                    unsigned long action, void *hcpu)
1334{
1335        long cpu = (long)hcpu;
1336        int err = 0;
1337
1338        switch (action) {
1339        case CPU_UP_PREPARE:
1340        case CPU_UP_PREPARE_FROZEN:
1341                mutex_lock(&cache_chain_mutex);
1342                err = cpuup_prepare(cpu);
1343                mutex_unlock(&cache_chain_mutex);
1344                break;
1345        case CPU_ONLINE:
1346        case CPU_ONLINE_FROZEN:
1347                start_cpu_timer(cpu);
1348                break;
1349#ifdef CONFIG_HOTPLUG_CPU
1350        case CPU_DOWN_PREPARE:
1351        case CPU_DOWN_PREPARE_FROZEN:
1352                /*
1353                 * Shutdown cache reaper. Note that the cache_chain_mutex is
1354                 * held so that if cache_reap() is invoked it cannot do
1355                 * anything expensive but will only modify reap_work
1356                 * and reschedule the timer.
1357                */
1358                cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1359                /* Now the cache_reaper is guaranteed to be not running. */
1360                per_cpu(slab_reap_work, cpu).work.func = NULL;
1361                break;
1362        case CPU_DOWN_FAILED:
1363        case CPU_DOWN_FAILED_FROZEN:
1364                start_cpu_timer(cpu);
1365                break;
1366        case CPU_DEAD:
1367        case CPU_DEAD_FROZEN:
1368                /*
1369                 * Even if all the cpus of a node are down, we don't free the
1370                 * kmem_list3 of any cache. This to avoid a race between
1371                 * cpu_down, and a kmalloc allocation from another cpu for
1372                 * memory from the node of the cpu going down.  The list3
1373                 * structure is usually allocated from kmem_cache_create() and
1374                 * gets destroyed at kmem_cache_destroy().
1375                 */
1376                /* fall through */
1377#endif
1378        case CPU_UP_CANCELED:
1379        case CPU_UP_CANCELED_FROZEN:
1380                mutex_lock(&cache_chain_mutex);
1381                cpuup_canceled(cpu);
1382                mutex_unlock(&cache_chain_mutex);
1383                break;
1384        }
1385        return notifier_from_errno(err);
1386}
1387
1388static struct notifier_block __cpuinitdata cpucache_notifier = {
1389        &cpuup_callback, NULL, 0
1390};
1391
1392#if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1393/*
1394 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1395 * Returns -EBUSY if all objects cannot be drained so that the node is not
1396 * removed.
1397 *
1398 * Must hold cache_chain_mutex.
1399 */
1400static int __meminit drain_cache_nodelists_node(int node)
1401{
1402        struct kmem_cache *cachep;
1403        int ret = 0;
1404
1405        list_for_each_entry(cachep, &cache_chain, next) {
1406                struct kmem_list3 *l3;
1407
1408                l3 = cachep->nodelists[node];
1409                if (!l3)
1410                        continue;
1411
1412                drain_freelist(cachep, l3, l3->free_objects);
1413
1414                if (!list_empty(&l3->slabs_full) ||
1415                    !list_empty(&l3->slabs_partial)) {
1416                        ret = -EBUSY;
1417                        break;
1418                }
1419        }
1420        return ret;
1421}
1422
1423static int __meminit slab_memory_callback(struct notifier_block *self,
1424                                        unsigned long action, void *arg)
1425{
1426        struct memory_notify *mnb = arg;
1427        int ret = 0;
1428        int nid;
1429
1430        nid = mnb->status_change_nid;
1431        if (nid < 0)
1432                goto out;
1433
1434        switch (action) {
1435        case MEM_GOING_ONLINE:
1436                mutex_lock(&cache_chain_mutex);
1437                ret = init_cache_nodelists_node(nid);
1438                mutex_unlock(&cache_chain_mutex);
1439                break;
1440        case MEM_GOING_OFFLINE:
1441                mutex_lock(&cache_chain_mutex);
1442                ret = drain_cache_nodelists_node(nid);
1443                mutex_unlock(&cache_chain_mutex);
1444                break;
1445        case MEM_ONLINE:
1446        case MEM_OFFLINE:
1447        case MEM_CANCEL_ONLINE:
1448        case MEM_CANCEL_OFFLINE:
1449                break;
1450        }
1451out:
1452        return notifier_from_errno(ret);
1453}
1454#endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1455
1456/*
1457 * swap the static kmem_list3 with kmalloced memory
1458 */
1459static void __init init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
1460                                int nodeid)
1461{
1462        struct kmem_list3 *ptr;
1463
1464        ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_NOWAIT, nodeid);
1465        BUG_ON(!ptr);
1466
1467        memcpy(ptr, list, sizeof(struct kmem_list3));
1468        /*
1469         * Do not assume that spinlocks can be initialized via memcpy:
1470         */
1471        spin_lock_init(&ptr->list_lock);
1472
1473        MAKE_ALL_LISTS(cachep, ptr, nodeid);
1474        cachep->nodelists[nodeid] = ptr;
1475}
1476
1477/*
1478 * For setting up all the kmem_list3s for cache whose buffer_size is same as
1479 * size of kmem_list3.
1480 */
1481static void __init set_up_list3s(struct kmem_cache *cachep, int index)
1482{
1483        int node;
1484
1485        for_each_online_node(node) {
1486                cachep->nodelists[node] = &initkmem_list3[index + node];
1487                cachep->nodelists[node]->next_reap = jiffies +
1488                    REAPTIMEOUT_LIST3 +
1489                    ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1490        }
1491}
1492
1493/*
1494 * Initialisation.  Called after the page allocator have been initialised and
1495 * before smp_init().
1496 */
1497void __init kmem_cache_init(void)
1498{
1499        size_t left_over;
1500        struct cache_sizes *sizes;
1501        struct cache_names *names;
1502        int i;
1503        int order;
1504        int node;
1505
1506        if (num_possible_nodes() == 1)
1507                use_alien_caches = 0;
1508
1509        for (i = 0; i < NUM_INIT_LISTS; i++) {
1510                kmem_list3_init(&initkmem_list3[i]);
1511                if (i < MAX_NUMNODES)
1512                        cache_cache.nodelists[i] = NULL;
1513        }
1514        set_up_list3s(&cache_cache, CACHE_CACHE);
1515
1516        /*
1517         * Fragmentation resistance on low memory - only use bigger
1518         * page orders on machines with more than 32MB of memory if
1519         * not overridden on the command line.
1520         */
1521        if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
1522                slab_max_order = SLAB_MAX_ORDER_HI;
1523
1524        /* Bootstrap is tricky, because several objects are allocated
1525         * from caches that do not exist yet:
1526         * 1) initialize the cache_cache cache: it contains the struct
1527         *    kmem_cache structures of all caches, except cache_cache itself:
1528         *    cache_cache is statically allocated.
1529         *    Initially an __init data area is used for the head array and the
1530         *    kmem_list3 structures, it's replaced with a kmalloc allocated
1531         *    array at the end of the bootstrap.
1532         * 2) Create the first kmalloc cache.
1533         *    The struct kmem_cache for the new cache is allocated normally.
1534         *    An __init data area is used for the head array.
1535         * 3) Create the remaining kmalloc caches, with minimally sized
1536         *    head arrays.
1537         * 4) Replace the __init data head arrays for cache_cache and the first
1538         *    kmalloc cache with kmalloc allocated arrays.
1539         * 5) Replace the __init data for kmem_list3 for cache_cache and
1540         *    the other cache's with kmalloc allocated memory.
1541         * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1542         */
1543
1544        node = numa_mem_id();
1545
1546        /* 1) create the cache_cache */
1547        INIT_LIST_HEAD(&cache_chain);
1548        list_add(&cache_cache.next, &cache_chain);
1549        cache_cache.colour_off = cache_line_size();
1550        cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
1551        cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
1552
1553        /*
1554         * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1555         */
1556        cache_cache.buffer_size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
1557                                  nr_node_ids * sizeof(struct kmem_list3 *);
1558#if DEBUG
1559        cache_cache.obj_size = cache_cache.buffer_size;
1560#endif
1561        cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
1562                                        cache_line_size());
1563        cache_cache.reciprocal_buffer_size =
1564                reciprocal_value(cache_cache.buffer_size);
1565
1566        for (order = 0; order < MAX_ORDER; order++) {
1567                cache_estimate(order, cache_cache.buffer_size,
1568                        cache_line_size(), 0, &left_over, &cache_cache.num);
1569                if (cache_cache.num)
1570                        break;
1571        }
1572        BUG_ON(!cache_cache.num);
1573        cache_cache.gfporder = order;
1574        cache_cache.colour = left_over / cache_cache.colour_off;
1575        cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
1576                                      sizeof(struct slab), cache_line_size());
1577
1578        /* 2+3) create the kmalloc caches */
1579        sizes = malloc_sizes;
1580        names = cache_names;
1581
1582        /*
1583         * Initialize the caches that provide memory for the array cache and the
1584         * kmem_list3 structures first.  Without this, further allocations will
1585         * bug.
1586         */
1587
1588        sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
1589                                        sizes[INDEX_AC].cs_size,
1590                                        ARCH_KMALLOC_MINALIGN,
1591                                        ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1592                                        NULL);
1593
1594        if (INDEX_AC != INDEX_L3) {
1595                sizes[INDEX_L3].cs_cachep =
1596                        kmem_cache_create(names[INDEX_L3].name,
1597                                sizes[INDEX_L3].cs_size,
1598                                ARCH_KMALLOC_MINALIGN,
1599                                ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1600                                NULL);
1601        }
1602
1603        slab_early_init = 0;
1604
1605        while (sizes->cs_size != ULONG_MAX) {
1606                /*
1607                 * For performance, all the general caches are L1 aligned.
1608                 * This should be particularly beneficial on SMP boxes, as it
1609                 * eliminates "false sharing".
1610                 * Note for systems short on memory removing the alignment will
1611                 * allow tighter packing of the smaller caches.
1612                 */
1613                if (!sizes->cs_cachep) {
1614                        sizes->cs_cachep = kmem_cache_create(names->name,
1615                                        sizes->cs_size,
1616                                        ARCH_KMALLOC_MINALIGN,
1617                                        ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1618                                        NULL);
1619                }
1620#ifdef CONFIG_ZONE_DMA
1621                sizes->cs_dmacachep = kmem_cache_create(
1622                                        names->name_dma,
1623                                        sizes->cs_size,
1624                                        ARCH_KMALLOC_MINALIGN,
1625                                        ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
1626                                                SLAB_PANIC,
1627                                        NULL);
1628#endif
1629                sizes++;
1630                names++;
1631        }
1632        /* 4) Replace the bootstrap head arrays */
1633        {
1634                struct array_cache *ptr;
1635
1636                ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1637
1638                BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
1639                memcpy(ptr, cpu_cache_get(&cache_cache),
1640                       sizeof(struct arraycache_init));
1641                /*
1642                 * Do not assume that spinlocks can be initialized via memcpy:
1643                 */
1644                spin_lock_init(&ptr->lock);
1645
1646                cache_cache.array[smp_processor_id()] = ptr;
1647
1648                ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1649
1650                BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
1651                       != &initarray_generic.cache);
1652                memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
1653                       sizeof(struct arraycache_init));
1654                /*
1655                 * Do not assume that spinlocks can be initialized via memcpy:
1656                 */
1657                spin_lock_init(&ptr->lock);
1658
1659                malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
1660                    ptr;
1661        }
1662        /* 5) Replace the bootstrap kmem_list3's */
1663        {
1664                int nid;
1665
1666                for_each_online_node(nid) {
1667                        init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid);
1668
1669                        init_list(malloc_sizes[INDEX_AC].cs_cachep,
1670                                  &initkmem_list3[SIZE_AC + nid], nid);
1671
1672                        if (INDEX_AC != INDEX_L3) {
1673                                init_list(malloc_sizes[INDEX_L3].cs_cachep,
1674                                          &initkmem_list3[SIZE_L3 + nid], nid);
1675                        }
1676                }
1677        }
1678
1679        g_cpucache_up = EARLY;
1680}
1681
1682void __init kmem_cache_init_late(void)
1683{
1684        struct kmem_cache *cachep;
1685
1686        g_cpucache_up = LATE;
1687
1688        /* 6) resize the head arrays to their final sizes */
1689        mutex_lock(&cache_chain_mutex);
1690        list_for_each_entry(cachep, &cache_chain, next)
1691                if (enable_cpucache(cachep, GFP_NOWAIT))
1692                        BUG();
1693        mutex_unlock(&cache_chain_mutex);
1694
1695        /* Annotate slab for lockdep -- annotate the malloc caches */
1696        init_lock_keys();
1697
1698        /* Done! */
1699        g_cpucache_up = FULL;
1700
1701        /*
1702         * Register a cpu startup notifier callback that initializes
1703         * cpu_cache_get for all new cpus
1704         */
1705        register_cpu_notifier(&cpucache_notifier);
1706
1707#ifdef CONFIG_NUMA
1708        /*
1709         * Register a memory hotplug callback that initializes and frees
1710         * nodelists.
1711         */
1712        hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1713#endif
1714
1715        /*
1716         * The reap timers are started later, with a module init call: That part
1717         * of the kernel is not yet operational.
1718         */
1719}
1720
1721static int __init cpucache_init(void)
1722{
1723        int cpu;
1724
1725        /*
1726         * Register the timers that return unneeded pages to the page allocator
1727         */
1728        for_each_online_cpu(cpu)
1729                start_cpu_timer(cpu);
1730        return 0;
1731}
1732__initcall(cpucache_init);
1733
1734static noinline void
1735slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1736{
1737        struct kmem_list3 *l3;
1738        struct slab *slabp;
1739        unsigned long flags;
1740        int node;
1741
1742        printk(KERN_WARNING
1743                "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1744                nodeid, gfpflags);
1745        printk(KERN_WARNING "  cache: %s, object size: %d, order: %d\n",
1746                cachep->name, cachep->buffer_size, cachep->gfporder);
1747
1748        for_each_online_node(node) {
1749                unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
1750                unsigned long active_slabs = 0, num_slabs = 0;
1751
1752                l3 = cachep->nodelists[node];
1753                if (!l3)
1754                        continue;
1755
1756                spin_lock_irqsave(&l3->list_lock, flags);
1757                list_for_each_entry(slabp, &l3->slabs_full, list) {
1758                        active_objs += cachep->num;
1759                        active_slabs++;
1760                }
1761                list_for_each_entry(slabp, &l3->slabs_partial, list) {
1762                        active_objs += slabp->inuse;
1763                        active_slabs++;
1764                }
1765                list_for_each_entry(slabp, &l3->slabs_free, list)
1766                        num_slabs++;
1767
1768                free_objects += l3->free_objects;
1769                spin_unlock_irqrestore(&l3->list_lock, flags);
1770
1771                num_slabs += active_slabs;
1772                num_objs = num_slabs * cachep->num;
1773                printk(KERN_WARNING
1774                        "  node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1775                        node, active_slabs, num_slabs, active_objs, num_objs,
1776                        free_objects);
1777        }
1778}
1779
1780/*
1781 * Interface to system's page allocator. No need to hold the cache-lock.
1782 *
1783 * If we requested dmaable memory, we will get it. Even if we
1784 * did not request dmaable memory, we might get it, but that
1785 * would be relatively rare and ignorable.
1786 */
1787static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
1788{
1789        struct page *page;
1790        int nr_pages;
1791        int i;
1792
1793#ifndef CONFIG_MMU
1794        /*
1795         * Nommu uses slab's for process anonymous memory allocations, and thus
1796         * requires __GFP_COMP to properly refcount higher order allocations
1797         */
1798        flags |= __GFP_COMP;
1799#endif
1800
1801        flags |= cachep->gfpflags;
1802        if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1803                flags |= __GFP_RECLAIMABLE;
1804
1805        page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1806        if (!page) {
1807                if (!(flags & __GFP_NOWARN) && printk_ratelimit())
1808                        slab_out_of_memory(cachep, flags, nodeid);
1809                return NULL;
1810        }
1811
1812        nr_pages = (1 << cachep->gfporder);
1813        if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1814                add_zone_page_state(page_zone(page),
1815                        NR_SLAB_RECLAIMABLE, nr_pages);
1816        else
1817                add_zone_page_state(page_zone(page),
1818                        NR_SLAB_UNRECLAIMABLE, nr_pages);
1819        for (i = 0; i < nr_pages; i++)
1820                __SetPageSlab(page + i);
1821
1822        if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1823                kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1824
1825                if (cachep->ctor)
1826                        kmemcheck_mark_uninitialized_pages(page, nr_pages);
1827                else
1828                        kmemcheck_mark_unallocated_pages(page, nr_pages);
1829        }
1830
1831        return page_address(page);
1832}
1833
1834/*
1835 * Interface to system's page release.
1836 */
1837static void kmem_freepages(struct kmem_cache *cachep, void *addr)
1838{
1839        unsigned long i = (1 << cachep->gfporder);
1840        struct page *page = virt_to_page(addr);
1841        const unsigned long nr_freed = i;
1842
1843        kmemcheck_free_shadow(page, cachep->gfporder);
1844
1845        if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1846                sub_zone_page_state(page_zone(page),
1847                                NR_SLAB_RECLAIMABLE, nr_freed);
1848        else
1849                sub_zone_page_state(page_zone(page),
1850                                NR_SLAB_UNRECLAIMABLE, nr_freed);
1851        while (i--) {
1852                BUG_ON(!PageSlab(page));
1853                __ClearPageSlab(page);
1854                page++;
1855        }
1856        if (current->reclaim_state)
1857                current->reclaim_state->reclaimed_slab += nr_freed;
1858        free_pages((unsigned long)addr, cachep->gfporder);
1859}
1860
1861static void kmem_rcu_free(struct rcu_head *head)
1862{
1863        struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
1864        struct kmem_cache *cachep = slab_rcu->cachep;
1865
1866        kmem_freepages(cachep, slab_rcu->addr);
1867        if (OFF_SLAB(cachep))
1868                kmem_cache_free(cachep->slabp_cache, slab_rcu);
1869}
1870
1871#if DEBUG
1872
1873#ifdef CONFIG_DEBUG_PAGEALLOC
1874static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1875                            unsigned long caller)
1876{
1877        int size = obj_size(cachep);
1878
1879        addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1880
1881        if (size < 5 * sizeof(unsigned long))
1882                return;
1883
1884        *addr++ = 0x12345678;
1885        *addr++ = caller;
1886        *addr++ = smp_processor_id();
1887        size -= 3 * sizeof(unsigned long);
1888        {
1889                unsigned long *sptr = &caller;
1890                unsigned long svalue;
1891
1892                while (!kstack_end(sptr)) {
1893                        svalue = *sptr++;
1894                        if (kernel_text_address(svalue)) {
1895                                *addr++ = svalue;
1896                                size -= sizeof(unsigned long);
1897                                if (size <= sizeof(unsigned long))
1898                                        break;
1899                        }
1900                }
1901
1902        }
1903        *addr++ = 0x87654321;
1904}
1905#endif
1906
1907static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1908{
1909        int size = obj_size(cachep);
1910        addr = &((char *)addr)[obj_offset(cachep)];
1911
1912        memset(addr, val, size);
1913        *(unsigned char *)(addr + size - 1) = POISON_END;
1914}
1915
1916static void dump_line(char *data, int offset, int limit)
1917{
1918        int i;
1919        unsigned char error = 0;
1920        int bad_count = 0;
1921
1922        printk(KERN_ERR "%03x: ", offset);
1923        for (i = 0; i < limit; i++) {
1924                if (data[offset + i] != POISON_FREE) {
1925                        error = data[offset + i];
1926                        bad_count++;
1927                }
1928        }
1929        print_hex_dump(KERN_CONT, "", 0, 16, 1,
1930                        &data[offset], limit, 1);
1931
1932        if (bad_count == 1) {
1933                error ^= POISON_FREE;
1934                if (!(error & (error - 1))) {
1935                        printk(KERN_ERR "Single bit error detected. Probably "
1936                                        "bad RAM.\n");
1937#ifdef CONFIG_X86
1938                        printk(KERN_ERR "Run memtest86+ or a similar memory "
1939                                        "test tool.\n");
1940#else
1941                        printk(KERN_ERR "Run a memory test tool.\n");
1942#endif
1943                }
1944        }
1945}
1946#endif
1947
1948#if DEBUG
1949
1950static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1951{
1952        int i, size;
1953        char *realobj;
1954
1955        if (cachep->flags & SLAB_RED_ZONE) {
1956                printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
1957                        *dbg_redzone1(cachep, objp),
1958                        *dbg_redzone2(cachep, objp));
1959        }
1960
1961        if (cachep->flags & SLAB_STORE_USER) {
1962                printk(KERN_ERR "Last user: [<%p>]",
1963                        *dbg_userword(cachep, objp));
1964                print_symbol("(%s)",
1965                                (unsigned long)*dbg_userword(cachep, objp));
1966                printk("\n");
1967        }
1968        realobj = (char *)objp + obj_offset(cachep);
1969        size = obj_size(cachep);
1970        for (i = 0; i < size && lines; i += 16, lines--) {
1971                int limit;
1972                limit = 16;
1973                if (i + limit > size)
1974                        limit = size - i;
1975                dump_line(realobj, i, limit);
1976        }
1977}
1978
1979static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1980{
1981        char *realobj;
1982        int size, i;
1983        int lines = 0;
1984
1985        realobj = (char *)objp + obj_offset(cachep);
1986        size = obj_size(cachep);
1987
1988        for (i = 0; i < size; i++) {
1989                char exp = POISON_FREE;
1990                if (i == size - 1)
1991                        exp = POISON_END;
1992                if (realobj[i] != exp) {
1993                        int limit;
1994                        /* Mismatch ! */
1995                        /* Print header */
1996                        if (lines == 0) {
1997                                printk(KERN_ERR
1998                                        "Slab corruption (%s): %s start=%p, len=%d\n",
1999                                        print_tainted(), cachep->name, realobj, size);
2000                                print_objinfo(cachep, objp, 0);
2001                        }
2002                        /* Hexdump the affected line */
2003                        i = (i / 16) * 16;
2004                        limit = 16;
2005                        if (i + limit > size)
2006                                limit = size - i;
2007                        dump_line(realobj, i, limit);
2008                        i += 16;
2009                        lines++;
2010                        /* Limit to 5 lines */
2011                        if (lines > 5)
2012                                break;
2013                }
2014        }
2015        if (lines != 0) {
2016                /* Print some data about the neighboring objects, if they
2017                 * exist:
2018                 */
2019                struct slab *slabp = virt_to_slab(objp);
2020                unsigned int objnr;
2021
2022                objnr = obj_to_index(cachep, slabp, objp);
2023                if (objnr) {
2024                        objp = index_to_obj(cachep, slabp, objnr - 1);
2025                        realobj = (char *)objp + obj_offset(cachep);
2026                        printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
2027                               realobj, size);
2028                        print_objinfo(cachep, objp, 2);
2029                }
2030                if (objnr + 1 < cachep->num) {
2031                        objp = index_to_obj(cachep, slabp, objnr + 1);
2032                        realobj = (char *)objp + obj_offset(cachep);
2033                        printk(KERN_ERR "Next obj: start=%p, len=%d\n",
2034                               realobj, size);
2035                        print_objinfo(cachep, objp, 2);
2036                }
2037        }
2038}
2039#endif
2040
2041#if DEBUG
2042static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
2043{
2044        int i;
2045        for (i = 0; i < cachep->num; i++) {
2046                void *objp = index_to_obj(cachep, slabp, i);
2047
2048                if (cachep->flags & SLAB_POISON) {
2049#ifdef CONFIG_DEBUG_PAGEALLOC
2050                        if (cachep->buffer_size % PAGE_SIZE == 0 &&
2051                                        OFF_SLAB(cachep))
2052                                kernel_map_pages(virt_to_page(objp),
2053                                        cachep->buffer_size / PAGE_SIZE, 1);
2054                        else
2055                                check_poison_obj(cachep, objp);
2056#else
2057                        check_poison_obj(cachep, objp);
2058#endif
2059                }
2060                if (cachep->flags & SLAB_RED_ZONE) {
2061                        if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2062                                slab_error(cachep, "start of a freed object "
2063                                           "was overwritten");
2064                        if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2065                                slab_error(cachep, "end of a freed object "
2066                                           "was overwritten");
2067                }
2068        }
2069}
2070#else
2071static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
2072{
2073}
2074#endif
2075
2076/**
2077 * slab_destroy - destroy and release all objects in a slab
2078 * @cachep: cache pointer being destroyed
2079 * @slabp: slab pointer being destroyed
2080 *
2081 * Destroy all the objs in a slab, and release the mem back to the system.
2082 * Before calling the slab must have been unlinked from the cache.  The
2083 * cache-lock is not held/needed.
2084 */
2085static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
2086{
2087        void *addr = slabp->s_mem - slabp->colouroff;
2088
2089        slab_destroy_debugcheck(cachep, slabp);
2090        if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
2091                struct slab_rcu *slab_rcu;
2092
2093                slab_rcu = (struct slab_rcu *)slabp;
2094                slab_rcu->cachep = cachep;
2095                slab_rcu->addr = addr;
2096                call_rcu(&slab_rcu->head, kmem_rcu_free);
2097        } else {
2098                kmem_freepages(cachep, addr);
2099                if (OFF_SLAB(cachep))
2100                        kmem_cache_free(cachep->slabp_cache, slabp);
2101        }
2102}
2103
2104static void __kmem_cache_destroy(struct kmem_cache *cachep)
2105{
2106        int i;
2107        struct kmem_list3 *l3;
2108
2109        for_each_online_cpu(i)
2110            kfree(cachep->array[i]);
2111
2112        /* NUMA: free the list3 structures */
2113        for_each_online_node(i) {
2114                l3 = cachep->nodelists[i];
2115                if (l3) {
2116                        kfree(l3->shared);
2117                        free_alien_cache(l3->alien);
2118                        kfree(l3);
2119                }
2120        }
2121        kmem_cache_free(&cache_cache, cachep);
2122}
2123
2124
2125/**
2126 * calculate_slab_order - calculate size (page order) of slabs
2127 * @cachep: pointer to the cache that is being created
2128 * @size: size of objects to be created in this cache.
2129 * @align: required alignment for the objects.
2130 * @flags: slab allocation flags
2131 *
2132 * Also calculates the number of objects per slab.
2133 *
2134 * This could be made much more intelligent.  For now, try to avoid using
2135 * high order pages for slabs.  When the gfp() functions are more friendly
2136 * towards high-order requests, this should be changed.
2137 */
2138static size_t calculate_slab_order(struct kmem_cache *cachep,
2139                        size_t size, size_t align, unsigned long flags)
2140{
2141        unsigned long offslab_limit;
2142        size_t left_over = 0;
2143        int gfporder;
2144
2145        for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
2146                unsigned int num;
2147                size_t remainder;
2148
2149                cache_estimate(gfporder, size, align, flags, &remainder, &num);
2150                if (!num)
2151                        continue;
2152
2153                if (flags & CFLGS_OFF_SLAB) {
2154                        /*
2155                         * Max number of objs-per-slab for caches which
2156                         * use off-slab slabs. Needed to avoid a possible
2157                         * looping condition in cache_grow().
2158                         */
2159                        offslab_limit = size - sizeof(struct slab);
2160                        offslab_limit /= sizeof(kmem_bufctl_t);
2161
2162                        if (num > offslab_limit)
2163                                break;
2164                }
2165
2166                /* Found something acceptable - save it away */
2167                cachep->num = num;
2168                cachep->gfporder = gfporder;
2169                left_over = remainder;
2170
2171                /*
2172                 * A VFS-reclaimable slab tends to have most allocations
2173                 * as GFP_NOFS and we really don't want to have to be allocating
2174                 * higher-order pages when we are unable to shrink dcache.
2175                 */
2176                if (flags & SLAB_RECLAIM_ACCOUNT)
2177                        break;
2178
2179                /*
2180                 * Large number of objects is good, but very large slabs are
2181                 * currently bad for the gfp()s.
2182                 */
2183                if (gfporder >= slab_max_order)
2184                        break;
2185
2186                /*
2187                 * Acceptable internal fragmentation?
2188                 */
2189                if (left_over * 8 <= (PAGE_SIZE << gfporder))
2190                        break;
2191        }
2192        return left_over;
2193}
2194
2195static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
2196{
2197        if (g_cpucache_up == FULL)
2198                return enable_cpucache(cachep, gfp);
2199
2200        if (g_cpucache_up == NONE) {
2201                /*
2202                 * Note: the first kmem_cache_create must create the cache
2203                 * that's used by kmalloc(24), otherwise the creation of
2204                 * further caches will BUG().
2205                 */
2206                cachep->array[smp_processor_id()] = &initarray_generic.cache;
2207
2208                /*
2209                 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
2210                 * the first cache, then we need to set up all its list3s,
2211                 * otherwise the creation of further caches will BUG().
2212                 */
2213                set_up_list3s(cachep, SIZE_AC);
2214                if (INDEX_AC == INDEX_L3)
2215                        g_cpucache_up = PARTIAL_L3;
2216                else
2217                        g_cpucache_up = PARTIAL_AC;
2218        } else {
2219                cachep->array[smp_processor_id()] =
2220                        kmalloc(sizeof(struct arraycache_init), gfp);
2221
2222                if (g_cpucache_up == PARTIAL_AC) {
2223                        set_up_list3s(cachep, SIZE_L3);
2224                        g_cpucache_up = PARTIAL_L3;
2225                } else {
2226                        int node;
2227                        for_each_online_node(node) {
2228                                cachep->nodelists[node] =
2229                                    kmalloc_node(sizeof(struct kmem_list3),
2230                                                gfp, node);
2231                                BUG_ON(!cachep->nodelists[node]);
2232                                kmem_list3_init(cachep->nodelists[node]);
2233                        }
2234                }
2235        }
2236        cachep->nodelists[numa_mem_id()]->next_reap =
2237                        jiffies + REAPTIMEOUT_LIST3 +
2238                        ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
2239
2240        cpu_cache_get(cachep)->avail = 0;
2241        cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
2242        cpu_cache_get(cachep)->batchcount = 1;
2243        cpu_cache_get(cachep)->touched = 0;
2244        cachep->batchcount = 1;
2245        cachep->limit = BOOT_CPUCACHE_ENTRIES;
2246        return 0;
2247}
2248
2249/**
2250 * kmem_cache_create - Create a cache.
2251 * @name: A string which is used in /proc/slabinfo to identify this cache.
2252 * @size: The size of objects to be created in this cache.
2253 * @align: The required alignment for the objects.
2254 * @flags: SLAB flags
2255 * @ctor: A constructor for the objects.
2256 *
2257 * Returns a ptr to the cache on success, NULL on failure.
2258 * Cannot be called within a int, but can be interrupted.
2259 * The @ctor is run when new pages are allocated by the cache.
2260 *
2261 * @name must be valid until the cache is destroyed. This implies that
2262 * the module calling this has to destroy the cache before getting unloaded.
2263 *
2264 * The flags are
2265 *
2266 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2267 * to catch references to uninitialised memory.
2268 *
2269 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2270 * for buffer overruns.
2271 *
2272 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2273 * cacheline.  This can be beneficial if you're counting cycles as closely
2274 * as davem.
2275 */
2276struct kmem_cache *
2277kmem_cache_create (const char *name, size_t size, size_t align,
2278        unsigned long flags, void (*ctor)(void *))
2279{
2280        size_t left_over, slab_size, ralign;
2281        struct kmem_cache *cachep = NULL, *pc;
2282        gfp_t gfp;
2283
2284        /*
2285         * Sanity checks... these are all serious usage bugs.
2286         */
2287        if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
2288            size > KMALLOC_MAX_SIZE) {
2289                printk(KERN_ERR "%s: Early error in slab %s\n", __func__,
2290                                name);
2291                BUG();
2292        }
2293
2294        /*
2295         * We use cache_chain_mutex to ensure a consistent view of
2296         * cpu_online_mask as well.  Please see cpuup_callback
2297         */
2298        if (slab_is_available()) {
2299                get_online_cpus();
2300                mutex_lock(&cache_chain_mutex);
2301        }
2302
2303        list_for_each_entry(pc, &cache_chain, next) {
2304                char tmp;
2305                int res;
2306
2307                /*
2308                 * This happens when the module gets unloaded and doesn't
2309                 * destroy its slab cache and no-one else reuses the vmalloc
2310                 * area of the module.  Print a warning.
2311                 */
2312                res = probe_kernel_address(pc->name, tmp);
2313                if (res) {
2314                        printk(KERN_ERR
2315                               "SLAB: cache with size %d has lost its name\n",
2316                               pc->buffer_size);
2317                        continue;
2318                }
2319
2320                if (!strcmp(pc->name, name)) {
2321                        printk(KERN_ERR
2322                               "kmem_cache_create: duplicate cache %s\n", name);
2323                        dump_stack();
2324                        goto oops;
2325                }
2326        }
2327
2328#if DEBUG
2329        WARN_ON(strchr(name, ' '));     /* It confuses parsers */
2330#if FORCED_DEBUG
2331        /*
2332         * Enable redzoning and last user accounting, except for caches with
2333         * large objects, if the increased size would increase the object size
2334         * above the next power of two: caches with object sizes just above a
2335         * power of two have a significant amount of internal fragmentation.
2336         */
2337        if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2338                                                2 * sizeof(unsigned long long)))
2339                flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2340        if (!(flags & SLAB_DESTROY_BY_RCU))
2341                flags |= SLAB_POISON;
2342#endif
2343        if (flags & SLAB_DESTROY_BY_RCU)
2344                BUG_ON(flags & SLAB_POISON);
2345#endif
2346        /*
2347         * Always checks flags, a caller might be expecting debug support which
2348         * isn't available.
2349         */
2350        BUG_ON(flags & ~CREATE_MASK);
2351
2352        /*
2353         * Check that size is in terms of words.  This is needed to avoid
2354         * unaligned accesses for some archs when redzoning is used, and makes
2355         * sure any on-slab bufctl's are also correctly aligned.
2356         */
2357        if (size & (BYTES_PER_WORD - 1)) {
2358                size += (BYTES_PER_WORD - 1);
2359                size &= ~(BYTES_PER_WORD - 1);
2360        }
2361
2362        /* calculate the final buffer alignment: */
2363
2364        /* 1) arch recommendation: can be overridden for debug */
2365        if (flags & SLAB_HWCACHE_ALIGN) {
2366                /*
2367                 * Default alignment: as specified by the arch code.  Except if
2368                 * an object is really small, then squeeze multiple objects into
2369                 * one cacheline.
2370                 */
2371                ralign = cache_line_size();
2372                while (size <= ralign / 2)
2373                        ralign /= 2;
2374        } else {
2375                ralign = BYTES_PER_WORD;
2376        }
2377
2378        /*
2379         * Redzoning and user store require word alignment or possibly larger.
2380         * Note this will be overridden by architecture or caller mandated
2381         * alignment if either is greater than BYTES_PER_WORD.
2382         */
2383        if (flags & SLAB_STORE_USER)
2384                ralign = BYTES_PER_WORD;
2385
2386        if (flags & SLAB_RED_ZONE) {
2387                ralign = REDZONE_ALIGN;
2388                /* If redzoning, ensure that the second redzone is suitably
2389                 * aligned, by adjusting the object size accordingly. */
2390                size += REDZONE_ALIGN - 1;
2391                size &= ~(REDZONE_ALIGN - 1);
2392        }
2393
2394        /* 2) arch mandated alignment */
2395        if (ralign < ARCH_SLAB_MINALIGN) {
2396                ralign = ARCH_SLAB_MINALIGN;
2397        }
2398        /* 3) caller mandated alignment */
2399        if (ralign < align) {
2400                ralign = align;
2401        }
2402        /* disable debug if necessary */
2403        if (ralign > __alignof__(unsigned long long))
2404                flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2405        /*
2406         * 4) Store it.
2407         */
2408        align = ralign;
2409
2410        if (slab_is_available())
2411                gfp = GFP_KERNEL;
2412        else
2413                gfp = GFP_NOWAIT;
2414
2415        /* Get cache's description obj. */
2416        cachep = kmem_cache_zalloc(&cache_cache, gfp);
2417        if (!cachep)
2418                goto oops;
2419
2420        cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];
2421#if DEBUG
2422        cachep->obj_size = size;
2423
2424        /*
2425         * Both debugging options require word-alignment which is calculated
2426         * into align above.
2427         */
2428        if (flags & SLAB_RED_ZONE) {
2429                /* add space for red zone words */
2430                cachep->obj_offset += sizeof(unsigned long long);
2431                size += 2 * sizeof(unsigned long long);
2432        }
2433        if (flags & SLAB_STORE_USER) {
2434                /* user store requires one word storage behind the end of
2435                 * the real object. But if the second red zone needs to be
2436                 * aligned to 64 bits, we must allow that much space.
2437                 */
2438                if (flags & SLAB_RED_ZONE)
2439                        size += REDZONE_ALIGN;
2440                else
2441                        size += BYTES_PER_WORD;
2442        }
2443#if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2444        if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
2445            && cachep->obj_size > cache_line_size() && ALIGN(size, align) < PAGE_SIZE) {
2446                cachep->obj_offset += PAGE_SIZE - ALIGN(size, align);
2447                size = PAGE_SIZE;
2448        }
2449#endif
2450#endif
2451
2452        /*
2453         * Determine if the slab management is 'on' or 'off' slab.
2454         * (bootstrapping cannot cope with offslab caches so don't do
2455         * it too early on. Always use on-slab management when
2456         * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
2457         */
2458        if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init &&
2459            !(flags & SLAB_NOLEAKTRACE))
2460                /*
2461                 * Size is large, assume best to place the slab management obj
2462                 * off-slab (should allow better packing of objs).
2463                 */
2464                flags |= CFLGS_OFF_SLAB;
2465
2466        size = ALIGN(size, align);
2467
2468        left_over = calculate_slab_order(cachep, size, align, flags);
2469
2470        if (!cachep->num) {
2471                printk(KERN_ERR
2472                       "kmem_cache_create: couldn't create cache %s.\n", name);
2473                kmem_cache_free(&cache_cache, cachep);
2474                cachep = NULL;
2475                goto oops;
2476        }
2477        slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
2478                          + sizeof(struct slab), align);
2479
2480        /*
2481         * If the slab has been placed off-slab, and we have enough space then
2482         * move it on-slab. This is at the expense of any extra colouring.
2483         */
2484        if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2485                flags &= ~CFLGS_OFF_SLAB;
2486                left_over -= slab_size;
2487        }
2488
2489        if (flags & CFLGS_OFF_SLAB) {
2490                /* really off slab. No need for manual alignment */
2491                slab_size =
2492                    cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
2493
2494#ifdef CONFIG_PAGE_POISONING
2495                /* If we're going to use the generic kernel_map_pages()
2496                 * poisoning, then it's going to smash the contents of
2497                 * the redzone and userword anyhow, so switch them off.
2498                 */
2499                if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
2500                        flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2501#endif
2502        }
2503
2504        cachep->colour_off = cache_line_size();
2505        /* Offset must be a multiple of the alignment. */
2506        if (cachep->colour_off < align)
2507                cachep->colour_off = align;
2508        cachep->colour = left_over / cachep->colour_off;
2509        cachep->slab_size = slab_size;
2510        cachep->flags = flags;
2511        cachep->gfpflags = 0;
2512        if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
2513                cachep->gfpflags |= GFP_DMA;
2514        cachep->buffer_size = size;
2515        cachep->reciprocal_buffer_size = reciprocal_value(size);
2516
2517        if (flags & CFLGS_OFF_SLAB) {
2518                cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
2519                /*
2520                 * This is a possibility for one of the malloc_sizes caches.
2521                 * But since we go off slab only for object size greater than
2522                 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2523                 * this should not happen at all.
2524                 * But leave a BUG_ON for some lucky dude.
2525                 */
2526                BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
2527        }
2528        cachep->ctor = ctor;
2529        cachep->name = name;
2530
2531        if (setup_cpu_cache(cachep, gfp)) {
2532                __kmem_cache_destroy(cachep);
2533                cachep = NULL;
2534                goto oops;
2535        }
2536
2537        if (flags & SLAB_DEBUG_OBJECTS) {
2538                /*
2539                 * Would deadlock through slab_destroy()->call_rcu()->
2540                 * debug_object_activate()->kmem_cache_alloc().
2541                 */
2542                WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
2543
2544                slab_set_debugobj_lock_classes(cachep);
2545        }
2546
2547        /* cache setup completed, link it into the list */
2548        list_add(&cachep->next, &cache_chain);
2549oops:
2550        if (!cachep && (flags & SLAB_PANIC))
2551                panic("kmem_cache_create(): failed to create slab `%s'\n",
2552                      name);
2553        if (slab_is_available()) {
2554                mutex_unlock(&cache_chain_mutex);
2555                put_online_cpus();
2556        }
2557        return cachep;
2558}
2559EXPORT_SYMBOL(kmem_cache_create);
2560
2561#if DEBUG
2562static void check_irq_off(void)
2563{
2564        BUG_ON(!irqs_disabled());
2565}
2566
2567static void check_irq_on(void)
2568{
2569        BUG_ON(irqs_disabled());
2570}
2571
2572static void check_spinlock_acquired(struct kmem_cache *cachep)
2573{
2574#ifdef CONFIG_SMP
2575        check_irq_off();
2576        assert_spin_locked(&cachep->nodelists[numa_mem_id()]->list_lock);
2577#endif
2578}
2579
2580static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2581{
2582#ifdef CONFIG_SMP
2583        check_irq_off();
2584        assert_spin_locked(&cachep->nodelists[node]->list_lock);
2585#endif
2586}
2587
2588#else
2589#define check_irq_off() do { } while(0)
2590#define check_irq_on()  do { } while(0)
2591#define check_spinlock_acquired(x) do { } while(0)
2592#define check_spinlock_acquired_node(x, y) do { } while(0)
2593#endif
2594
2595static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
2596                        struct array_cache *ac,
2597                        int force, int node);
2598
2599static void do_drain(void *arg)
2600{
2601        struct kmem_cache *cachep = arg;
2602        struct array_cache *ac;
2603        int node = numa_mem_id();
2604
2605        check_irq_off();
2606        ac = cpu_cache_get(cachep);
2607        spin_lock(&cachep->nodelists[node]->list_lock);
2608        free_block(cachep, ac->entry, ac->avail, node);
2609        spin_unlock(&cachep->nodelists[node]->list_lock);
2610        ac->avail = 0;
2611}
2612
2613static void drain_cpu_caches(struct kmem_cache *cachep)
2614{
2615        struct kmem_list3 *l3;
2616        int node;
2617
2618        on_each_cpu(do_drain, cachep, 1);
2619        check_irq_on();
2620        for_each_online_node(node) {
2621                l3 = cachep->nodelists[node];
2622                if (l3 && l3->alien)
2623                        drain_alien_cache(cachep, l3->alien);
2624        }
2625
2626        for_each_online_node(node) {
2627                l3 = cachep->nodelists[node];
2628                if (l3)
2629                        drain_array(cachep, l3, l3->shared, 1, node);
2630        }
2631}
2632
2633/*
2634 * Remove slabs from the list of free slabs.
2635 * Specify the number of slabs to drain in tofree.
2636 *
2637 * Returns the actual number of slabs released.
2638 */
2639static int drain_freelist(struct kmem_cache *cache,
2640                        struct kmem_list3 *l3, int tofree)
2641{
2642        struct list_head *p;
2643        int nr_freed;
2644        struct slab *slabp;
2645
2646        nr_freed = 0;
2647        while (nr_freed < tofree && !list_empty(&l3->slabs_free)) {
2648
2649                spin_lock_irq(&l3->list_lock);
2650                p = l3->slabs_free.prev;
2651                if (p == &l3->slabs_free) {
2652                        spin_unlock_irq(&l3->list_lock);
2653                        goto out;
2654                }
2655
2656                slabp = list_entry(p, struct slab, list);
2657#if DEBUG
2658                BUG_ON(slabp->inuse);
2659#endif
2660                list_del(&slabp->list);
2661                /*
2662                 * Safe to drop the lock. The slab is no longer linked
2663                 * to the cache.
2664                 */
2665                l3->free_objects -= cache->num;
2666                spin_unlock_irq(&l3->list_lock);
2667                slab_destroy(cache, slabp);
2668                nr_freed++;
2669        }
2670out:
2671        return nr_freed;
2672}
2673
2674/* Called with cache_chain_mutex held to protect against cpu hotplug */
2675static int __cache_shrink(struct kmem_cache *cachep)
2676{
2677        int ret = 0, i = 0;
2678        struct kmem_list3 *l3;
2679
2680        drain_cpu_caches(cachep);
2681
2682        check_irq_on();
2683        for_each_online_node(i) {
2684                l3 = cachep->nodelists[i];
2685                if (!l3)
2686                        continue;
2687
2688                drain_freelist(cachep, l3, l3->free_objects);
2689
2690                ret += !list_empty(&l3->slabs_full) ||
2691                        !list_empty(&l3->slabs_partial);
2692        }
2693        return (ret ? 1 : 0);
2694}
2695
2696/**
2697 * kmem_cache_shrink - Shrink a cache.
2698 * @cachep: The cache to shrink.
2699 *
2700 * Releases as many slabs as possible for a cache.
2701 * To help debugging, a zero exit status indicates all slabs were released.
2702 */
2703int kmem_cache_shrink(struct kmem_cache *cachep)
2704{
2705        int ret;
2706        BUG_ON(!cachep || in_interrupt());
2707
2708        get_online_cpus();
2709        mutex_lock(&cache_chain_mutex);
2710        ret = __cache_shrink(cachep);
2711        mutex_unlock(&cache_chain_mutex);
2712        put_online_cpus();
2713        return ret;
2714}
2715EXPORT_SYMBOL(kmem_cache_shrink);
2716
2717/**
2718 * kmem_cache_destroy - delete a cache
2719 * @cachep: the cache to destroy
2720 *
2721 * Remove a &struct kmem_cache object from the slab cache.
2722 *
2723 * It is expected this function will be called by a module when it is
2724 * unloaded.  This will remove the cache completely, and avoid a duplicate
2725 * cache being allocated each time a module is loaded and unloaded, if the
2726 * module doesn't have persistent in-kernel storage across loads and unloads.
2727 *
2728 * The cache must be empty before calling this function.
2729 *
2730 * The caller must guarantee that no one will allocate memory from the cache
2731 * during the kmem_cache_destroy().
2732 */
2733void kmem_cache_destroy(struct kmem_cache *cachep)
2734{
2735        BUG_ON(!cachep || in_interrupt());
2736
2737        /* Find the cache in the chain of caches. */
2738        get_online_cpus();
2739        mutex_lock(&cache_chain_mutex);
2740        /*
2741         * the chain is never empty, cache_cache is never destroyed
2742         */
2743        list_del(&cachep->next);
2744        if (__cache_shrink(cachep)) {
2745                slab_error(cachep, "Can't free all objects");
2746                list_add(&cachep->next, &cache_chain);
2747                mutex_unlock(&cache_chain_mutex);
2748                put_online_cpus();
2749                return;
2750        }
2751
2752        if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
2753                rcu_barrier();
2754
2755        __kmem_cache_destroy(cachep);
2756        mutex_unlock(&cache_chain_mutex);
2757        put_online_cpus();
2758}
2759EXPORT_SYMBOL(kmem_cache_destroy);
2760
2761/*
2762 * Get the memory for a slab management obj.
2763 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2764 * always come from malloc_sizes caches.  The slab descriptor cannot
2765 * come from the same cache which is getting created because,
2766 * when we are searching for an appropriate cache for these
2767 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2768 * If we are creating a malloc_sizes cache here it would not be visible to
2769 * kmem_find_general_cachep till the initialization is complete.
2770 * Hence we cannot have slabp_cache same as the original cache.
2771 */
2772static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
2773                                   int colour_off, gfp_t local_flags,
2774                                   int nodeid)
2775{
2776        struct slab *slabp;
2777
2778        if (OFF_SLAB(cachep)) {
2779                /* Slab management obj is off-slab. */
2780                slabp = kmem_cache_alloc_node(cachep->slabp_cache,
2781                                              local_flags, nodeid);
2782                /*
2783                 * If the first object in the slab is leaked (it's allocated
2784                 * but no one has a reference to it), we want to make sure
2785                 * kmemleak does not treat the ->s_mem pointer as a reference
2786                 * to the object. Otherwise we will not report the leak.
2787                 */
2788                kmemleak_scan_area(&slabp->list, sizeof(struct list_head),
2789                                   local_flags);
2790                if (!slabp)
2791                        return NULL;
2792        } else {
2793                slabp = objp + colour_off;
2794                colour_off += cachep->slab_size;
2795        }
2796        slabp->inuse = 0;
2797        slabp->colouroff = colour_off;
2798        slabp->s_mem = objp + colour_off;
2799        slabp->nodeid = nodeid;
2800        slabp->free = 0;
2801        return slabp;
2802}
2803
2804static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
2805{
2806        return (kmem_bufctl_t *) (slabp + 1);
2807}
2808
2809static void cache_init_objs(struct kmem_cache *cachep,
2810                            struct slab *slabp)
2811{
2812        int i;
2813
2814        for (i = 0; i < cachep->num; i++) {
2815                void *objp = index_to_obj(cachep, slabp, i);
2816#if DEBUG
2817                /* need to poison the objs? */
2818                if (cachep->flags & SLAB_POISON)
2819                        poison_obj(cachep, objp, POISON_FREE);
2820                if (cachep->flags & SLAB_STORE_USER)
2821                        *dbg_userword(cachep, objp) = NULL;
2822
2823                if (cachep->flags & SLAB_RED_ZONE) {
2824                        *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2825                        *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2826                }
2827                /*
2828                 * Constructors are not allowed to allocate memory from the same
2829                 * cache which they are a constructor for.  Otherwise, deadlock.
2830                 * They must also be threaded.
2831                 */
2832                if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2833                        cachep->ctor(objp + obj_offset(cachep));
2834
2835                if (cachep->flags & SLAB_RED_ZONE) {
2836                        if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2837                                slab_error(cachep, "constructor overwrote the"
2838                                           " end of an object");
2839                        if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2840                                slab_error(cachep, "constructor overwrote the"
2841                                           " start of an object");
2842                }
2843                if ((cachep->buffer_size % PAGE_SIZE) == 0 &&
2844                            OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2845                        kernel_map_pages(virt_to_page(objp),
2846                                         cachep->buffer_size / PAGE_SIZE, 0);
2847#else
2848                if (cachep->ctor)
2849                        cachep->ctor(objp);
2850#endif
2851                slab_bufctl(slabp)[i] = i + 1;
2852        }
2853        slab_bufctl(slabp)[i - 1] = BUFCTL_END;
2854}
2855
2856static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2857{
2858        if (CONFIG_ZONE_DMA_FLAG) {
2859                if (flags & GFP_DMA)
2860                        BUG_ON(!(cachep->gfpflags & GFP_DMA));
2861                else
2862                        BUG_ON(cachep->gfpflags & GFP_DMA);
2863        }
2864}
2865
2866static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2867                                int nodeid)
2868{
2869        void *objp = index_to_obj(cachep, slabp, slabp->free);
2870        kmem_bufctl_t next;
2871
2872        slabp->inuse++;
2873        next = slab_bufctl(slabp)[slabp->free];
2874#if DEBUG
2875        slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2876        WARN_ON(slabp->nodeid != nodeid);
2877#endif
2878        slabp->free = next;
2879
2880        return objp;
2881}
2882
2883static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2884                                void *objp, int nodeid)
2885{
2886        unsigned int objnr = obj_to_index(cachep, slabp, objp);
2887
2888#if DEBUG
2889        /* Verify that the slab belongs to the intended node */
2890        WARN_ON(slabp->nodeid != nodeid);
2891
2892        if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
2893                printk(KERN_ERR "slab: double free detected in cache "
2894                                "'%s', objp %p\n", cachep->name, objp);
2895                BUG();
2896        }
2897#endif
2898        slab_bufctl(slabp)[objnr] = slabp->free;
2899        slabp->free = objnr;
2900        slabp->inuse--;
2901}
2902
2903/*
2904 * Map pages beginning at addr to the given cache and slab. This is required
2905 * for the slab allocator to be able to lookup the cache and slab of a
2906 * virtual address for kfree, ksize, and slab debugging.
2907 */
2908static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
2909                           void *addr)
2910{
2911        int nr_pages;
2912        struct page *page;
2913
2914        page = virt_to_page(addr);
2915
2916        nr_pages = 1;
2917        if (likely(!PageCompound(page)))
2918                nr_pages <<= cache->gfporder;
2919
2920        do {
2921                page_set_cache(page, cache);
2922                page_set_slab(page, slab);
2923                page++;
2924        } while (--nr_pages);
2925}
2926
2927/*
2928 * Grow (by 1) the number of slabs within a cache.  This is called by
2929 * kmem_cache_alloc() when there are no active objs left in a cache.
2930 */
2931static int cache_grow(struct kmem_cache *cachep,
2932                gfp_t flags, int nodeid, void *objp)
2933{
2934        struct slab *slabp;
2935        size_t offset;
2936        gfp_t local_flags;
2937        struct kmem_list3 *l3;
2938
2939        /*
2940         * Be lazy and only check for valid flags here,  keeping it out of the
2941         * critical path in kmem_cache_alloc().
2942         */
2943        BUG_ON(flags & GFP_SLAB_BUG_MASK);
2944        local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2945
2946        /* Take the l3 list lock to change the colour_next on this node */
2947        check_irq_off();
2948        l3 = cachep->nodelists[nodeid];
2949        spin_lock(&l3->list_lock);
2950
2951        /* Get colour for the slab, and cal the next value. */
2952        offset = l3->colour_next;
2953        l3->colour_next++;
2954        if (l3->colour_next >= cachep->colour)
2955                l3->colour_next = 0;
2956        spin_unlock(&l3->list_lock);
2957
2958        offset *= cachep->colour_off;
2959
2960        if (local_flags & __GFP_WAIT)
2961                local_irq_enable();
2962
2963        /*
2964         * The test for missing atomic flag is performed here, rather than
2965         * the more obvious place, simply to reduce the critical path length
2966         * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2967         * will eventually be caught here (where it matters).
2968         */
2969        kmem_flagcheck(cachep, flags);
2970
2971        /*
2972         * Get mem for the objs.  Attempt to allocate a physical page from
2973         * 'nodeid'.
2974         */
2975        if (!objp)
2976                objp = kmem_getpages(cachep, local_flags, nodeid);
2977        if (!objp)
2978                goto failed;
2979
2980        /* Get slab management. */
2981        slabp = alloc_slabmgmt(cachep, objp, offset,
2982                        local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
2983        if (!slabp)
2984                goto opps1;
2985
2986        slab_map_pages(cachep, slabp, objp);
2987
2988        cache_init_objs(cachep, slabp);
2989
2990        if (local_flags & __GFP_WAIT)
2991                local_irq_disable();
2992        check_irq_off();
2993        spin_lock(&l3->list_lock);
2994
2995        /* Make slab active. */
2996        list_add_tail(&slabp->list, &(l3->slabs_free));
2997        STATS_INC_GROWN(cachep);
2998        l3->free_objects += cachep->num;
2999        spin_unlock(&l3->list_lock);
3000        return 1;
3001opps1:
3002        kmem_freepages(cachep, objp);
3003failed:
3004        if (local_flags & __GFP_WAIT)
3005                local_irq_disable();
3006        return 0;
3007}
3008
3009#if DEBUG
3010
3011/*
3012 * Perform extra freeing checks:
3013 * - detect bad pointers.
3014 * - POISON/RED_ZONE checking
3015 */
3016static void kfree_debugcheck(const void *objp)
3017{
3018        if (!virt_addr_valid(objp)) {
3019                printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
3020                       (unsigned long)objp);
3021                BUG();
3022        }
3023}
3024
3025static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
3026{
3027        unsigned long long redzone1, redzone2;
3028
3029        redzone1 = *dbg_redzone1(cache, obj);
3030        redzone2 = *dbg_redzone2(cache, obj);
3031
3032        /*
3033         * Redzone is ok.
3034         */
3035        if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
3036                return;
3037
3038        if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
3039                slab_error(cache, "double free detected");
3040        else
3041                slab_error(cache, "memory outside object was overwritten");
3042
3043        printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
3044                        obj, redzone1, redzone2);
3045}
3046
3047static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
3048                                   void *caller)
3049{
3050        struct page *page;
3051        unsigned int objnr;
3052        struct slab *slabp;
3053
3054        BUG_ON(virt_to_cache(objp) != cachep);
3055
3056        objp -= obj_offset(cachep);
3057        kfree_debugcheck(objp);
3058        page = virt_to_head_page(objp);
3059
3060        slabp = page_get_slab(page);
3061
3062        if (cachep->flags & SLAB_RED_ZONE) {
3063                verify_redzone_free(cachep, objp);
3064                *dbg_redzone1(cachep, objp) = RED_INACTIVE;
3065                *dbg_redzone2(cachep, objp) = RED_INACTIVE;
3066        }
3067        if (cachep->flags & SLAB_STORE_USER)
3068                *dbg_userword(cachep, objp) = caller;
3069
3070        objnr = obj_to_index(cachep, slabp, objp);
3071
3072        BUG_ON(objnr >= cachep->num);
3073        BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
3074
3075#ifdef CONFIG_DEBUG_SLAB_LEAK
3076        slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
3077#endif
3078        if (cachep->flags & SLAB_POISON) {
3079#ifdef CONFIG_DEBUG_PAGEALLOC
3080                if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
3081                        store_stackinfo(cachep, objp, (unsigned long)caller);
3082                        kernel_map_pages(virt_to_page(objp),
3083                                         cachep->buffer_size / PAGE_SIZE, 0);
3084                } else {
3085                        poison_obj(cachep, objp, POISON_FREE);
3086                }
3087#else
3088                poison_obj(cachep, objp, POISON_FREE);
3089#endif
3090        }
3091        return objp;
3092}
3093
3094static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
3095{
3096        kmem_bufctl_t i;
3097        int entries = 0;
3098
3099        /* Check slab's freelist to see if this obj is there. */
3100        for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
3101                entries++;
3102                if (entries > cachep->num || i >= cachep->num)
3103                        goto bad;
3104        }
3105        if (entries != cachep->num - slabp->inuse) {
3106bad:
3107                printk(KERN_ERR "slab: Internal list corruption detected in "
3108                        "cache '%s'(%d), slabp %p(%d). Tainted(%s). Hexdump:\n",
3109                        cachep->name, cachep->num, slabp, slabp->inuse,
3110                        print_tainted());
3111                print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp,
3112                        sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t),
3113                        1);
3114                BUG();
3115        }
3116}
3117#else
3118#define kfree_debugcheck(x) do { } while(0)
3119#define cache_free_debugcheck(x,objp,z) (objp)
3120#define check_slabp(x,y) do { } while(0)
3121#endif
3122
3123static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
3124{
3125        int batchcount;
3126        struct kmem_list3 *l3;
3127        struct array_cache *ac;
3128        int node;
3129
3130retry:
3131        check_irq_off();
3132        node = numa_mem_id();
3133        ac = cpu_cache_get(cachep);
3134        batchcount = ac->batchcount;
3135        if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
3136                /*
3137                 * If there was little recent activity on this cache, then
3138                 * perform only a partial refill.  Otherwise we could generate
3139                 * refill bouncing.
3140                 */
3141                batchcount = BATCHREFILL_LIMIT;
3142        }
3143        l3 = cachep->nodelists[node];
3144
3145        BUG_ON(ac->avail > 0 || !l3);
3146        spin_lock(&l3->list_lock);
3147
3148        /* See if we can refill from the shared array */
3149        if (l3->shared && transfer_objects(ac, l3->shared, batchcount)) {
3150                l3->shared->touched = 1;
3151                goto alloc_done;
3152        }
3153
3154        while (batchcount > 0) {
3155                struct list_head *entry;
3156                struct slab *slabp;
3157                /* Get slab alloc is to come from. */
3158                entry = l3->slabs_partial.next;
3159                if (entry == &l3->slabs_partial) {
3160                        l3->free_touched = 1;
3161                        entry = l3->slabs_free.next;
3162                        if (entry == &l3->slabs_free)
3163                                goto must_grow;
3164                }
3165
3166                slabp = list_entry(entry, struct slab, list);
3167                check_slabp(cachep, slabp);
3168                check_spinlock_acquired(cachep);
3169
3170                /*
3171                 * The slab was either on partial or free list so
3172                 * there must be at least one object available for
3173                 * allocation.
3174                 */
3175                BUG_ON(slabp->inuse >= cachep->num);
3176
3177                while (slabp->inuse < cachep->num && batchcount--) {
3178                        STATS_INC_ALLOCED(cachep);
3179                        STATS_INC_ACTIVE(cachep);
3180                        STATS_SET_HIGH(cachep);
3181
3182                        ac->entry[ac->avail++] = slab_get_obj(cachep, slabp,
3183                                                            node);
3184                }
3185                check_slabp(cachep, slabp);
3186
3187                /* move slabp to correct slabp list: */
3188                list_del(&slabp->list);
3189                if (slabp->free == BUFCTL_END)
3190                        list_add(&slabp->list, &l3->slabs_full);
3191                else
3192                        list_add(&slabp->list, &l3->slabs_partial);
3193        }
3194
3195must_grow:
3196        l3->free_objects -= ac->avail;
3197alloc_done:
3198        spin_unlock(&l3->list_lock);
3199
3200        if (unlikely(!ac->avail)) {
3201                int x;
3202                x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
3203
3204                /* cache_grow can reenable interrupts, then ac could change. */
3205                ac = cpu_cache_get(cachep);
3206                if (!x && ac->avail == 0)       /* no objects in sight? abort */
3207                        return NULL;
3208
3209                if (!ac->avail)         /* objects refilled by interrupt? */
3210                        goto retry;
3211        }
3212        ac->touched = 1;
3213        return ac->entry[--ac->avail];
3214}
3215
3216static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
3217                                                gfp_t flags)
3218{
3219        might_sleep_if(flags & __GFP_WAIT);
3220#if DEBUG
3221        kmem_flagcheck(cachep, flags);
3222#endif
3223}
3224
3225#if DEBUG
3226static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
3227                                gfp_t flags, void *objp, void *caller)
3228{
3229        if (!objp)
3230                return objp;
3231        if (cachep->flags & SLAB_POISON) {
3232#ifdef CONFIG_DEBUG_PAGEALLOC
3233                if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
3234                        kernel_map_pages(virt_to_page(objp),
3235                                         cachep->buffer_size / PAGE_SIZE, 1);
3236                else
3237                        check_poison_obj(cachep, objp);
3238#else
3239                check_poison_obj(cachep, objp);
3240#endif
3241                poison_obj(cachep, objp, POISON_INUSE);
3242        }
3243        if (cachep->flags & SLAB_STORE_USER)
3244                *dbg_userword(cachep, objp) = caller;
3245
3246        if (cachep->flags & SLAB_RED_ZONE) {
3247                if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3248                                *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3249                        slab_error(cachep, "double free, or memory outside"
3250                                                " object was overwritten");
3251                        printk(KERN_ERR
3252                                "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3253                                objp, *dbg_redzone1(cachep, objp),
3254                                *dbg_redzone2(cachep, objp));
3255                }
3256                *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3257                *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3258        }
3259#ifdef CONFIG_DEBUG_SLAB_LEAK
3260        {
3261                struct slab *slabp;
3262                unsigned objnr;
3263
3264                slabp = page_get_slab(virt_to_head_page(objp));
3265                objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
3266                slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
3267        }
3268#endif
3269        objp += obj_offset(cachep);
3270        if (cachep->ctor && cachep->flags & SLAB_POISON)
3271                cachep->ctor(objp);
3272        if (ARCH_SLAB_MINALIGN &&
3273            ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
3274                printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3275                       objp, (int)ARCH_SLAB_MINALIGN);
3276        }
3277        return objp;
3278}
3279#else
3280#define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3281#endif
3282
3283static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
3284{
3285        if (cachep == &cache_cache)
3286                return false;
3287
3288        return should_failslab(obj_size(cachep), flags, cachep->flags);
3289}
3290
3291static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3292{
3293        void *objp;
3294        struct array_cache *ac;
3295
3296        check_irq_off();
3297
3298        ac = cpu_cache_get(cachep);
3299        if (likely(ac->avail)) {
3300                STATS_INC_ALLOCHIT(cachep);
3301                ac->touched = 1;
3302                objp = ac->entry[--ac->avail];
3303        } else {
3304                STATS_INC_ALLOCMISS(cachep);
3305                objp = cache_alloc_refill(cachep, flags);
3306                /*
3307                 * the 'ac' may be updated by cache_alloc_refill(),
3308                 * and kmemleak_erase() requires its correct value.
3309                 */
3310                ac = cpu_cache_get(cachep);
3311        }
3312        /*
3313         * To avoid a false negative, if an object that is in one of the
3314         * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3315         * treat the array pointers as a reference to the object.
3316         */
3317        if (objp)
3318                kmemleak_erase(&ac->entry[ac->avail]);
3319        return objp;
3320}
3321
3322#ifdef CONFIG_NUMA
3323/*
3324 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3325 *
3326 * If we are in_interrupt, then process context, including cpusets and
3327 * mempolicy, may not apply and should not be used for allocation policy.
3328 */
3329static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3330{
3331        int nid_alloc, nid_here;
3332
3333        if (in_interrupt() || (flags & __GFP_THISNODE))
3334                return NULL;
3335        nid_alloc = nid_here = numa_mem_id();
3336        if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3337                nid_alloc = cpuset_slab_spread_node();
3338        else if (current->mempolicy)
3339                nid_alloc = slab_node(current->mempolicy);
3340        if (nid_alloc != nid_here)
3341                return ____cache_alloc_node(cachep, flags, nid_alloc);
3342        return NULL;
3343}
3344
3345/*
3346 * Fallback function if there was no memory available and no objects on a
3347 * certain node and fall back is permitted. First we scan all the
3348 * available nodelists for available objects. If that fails then we
3349 * perform an allocation without specifying a node. This allows the page
3350 * allocator to do its reclaim / fallback magic. We then insert the
3351 * slab into the proper nodelist and then allocate from it.
3352 */
3353static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3354{
3355        struct zonelist *zonelist;
3356        gfp_t local_flags;
3357        struct zoneref *z;
3358        struct zone *zone;
3359        enum zone_type high_zoneidx = gfp_zone(flags);
3360        void *obj = NULL;
3361        int nid;
3362        unsigned int cpuset_mems_cookie;
3363
3364        if (flags & __GFP_THISNODE)
3365                return NULL;
3366
3367        local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
3368
3369retry_cpuset:
3370        cpuset_mems_cookie = get_mems_allowed();
3371        zonelist = node_zonelist(slab_node(current->mempolicy), flags);
3372
3373retry:
3374        /*
3375         * Look through allowed nodes for objects available
3376         * from existing per node queues.
3377         */
3378        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3379                nid = zone_to_nid(zone);
3380
3381                if (cpuset_zone_allowed_hardwall(zone, flags) &&
3382                        cache->nodelists[nid] &&
3383                        cache->nodelists[nid]->free_objects) {
3384                                obj = ____cache_alloc_node(cache,
3385                                        flags | GFP_THISNODE, nid);
3386                                if (obj)
3387                                        break;
3388                }
3389        }
3390
3391        if (!obj) {
3392                /*
3393                 * This allocation will be performed within the constraints
3394                 * of the current cpuset / memory policy requirements.
3395                 * We may trigger various forms of reclaim on the allowed
3396                 * set and go into memory reserves if necessary.
3397                 */
3398                if (local_flags & __GFP_WAIT)
3399                        local_irq_enable();
3400                kmem_flagcheck(cache, flags);
3401                obj = kmem_getpages(cache, local_flags, numa_mem_id());
3402                if (local_flags & __GFP_WAIT)
3403                        local_irq_disable();
3404                if (obj) {
3405                        /*
3406                         * Insert into the appropriate per node queues
3407                         */
3408                        nid = page_to_nid(virt_to_page(obj));
3409                        if (cache_grow(cache, flags, nid, obj)) {
3410                                obj = ____cache_alloc_node(cache,
3411                                        flags | GFP_THISNODE, nid);
3412                                if (!obj)
3413                                        /*
3414                                         * Another processor may allocate the
3415                                         * objects in the slab since we are
3416                                         * not holding any locks.
3417                                         */
3418                                        goto retry;
3419                        } else {
3420                                /* cache_grow already freed obj */
3421                                obj = NULL;
3422                        }
3423                }
3424        }
3425
3426        if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj))
3427                goto retry_cpuset;
3428        return obj;
3429}
3430
3431/*
3432 * A interface to enable slab creation on nodeid
3433 */
3434static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3435                                int nodeid)
3436{
3437        struct list_head *entry;
3438        struct slab *slabp;
3439        struct kmem_list3 *l3;
3440        void *obj;
3441        int x;
3442
3443        l3 = cachep->nodelists[nodeid];
3444        BUG_ON(!l3);
3445
3446retry:
3447        check_irq_off();
3448        spin_lock(&l3->list_lock);
3449        entry = l3->slabs_partial.next;
3450        if (entry == &l3->slabs_partial) {
3451                l3->free_touched = 1;
3452                entry = l3->slabs_free.next;
3453                if (entry == &l3->slabs_free)
3454                        goto must_grow;
3455        }
3456
3457        slabp = list_entry(entry, struct slab, list);
3458        check_spinlock_acquired_node(cachep, nodeid);
3459        check_slabp(cachep, slabp);
3460
3461        STATS_INC_NODEALLOCS(cachep);
3462        STATS_INC_ACTIVE(cachep);
3463        STATS_SET_HIGH(cachep);
3464
3465        BUG_ON(slabp->inuse == cachep->num);
3466
3467        obj = slab_get_obj(cachep, slabp, nodeid);
3468        check_slabp(cachep, slabp);
3469        l3->free_objects--;
3470        /* move slabp to correct slabp list: */
3471        list_del(&slabp->list);
3472
3473        if (slabp->free == BUFCTL_END)
3474                list_add(&slabp->list, &l3->slabs_full);
3475        else
3476                list_add(&slabp->list, &l3->slabs_partial);
3477
3478        spin_unlock(&l3->list_lock);
3479        goto done;
3480
3481must_grow:
3482        spin_unlock(&l3->list_lock);
3483        x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
3484        if (x)
3485                goto retry;
3486
3487        return fallback_alloc(cachep, flags);
3488
3489done:
3490        return obj;
3491}
3492
3493/**
3494 * kmem_cache_alloc_node - Allocate an object on the specified node
3495 * @cachep: The cache to allocate from.
3496 * @flags: See kmalloc().
3497 * @nodeid: node number of the target node.
3498 * @caller: return address of caller, used for debug information
3499 *
3500 * Identical to kmem_cache_alloc but it will allocate memory on the given
3501 * node, which can improve the performance for cpu bound structures.
3502 *
3503 * Fallback to other node is possible if __GFP_THISNODE is not set.
3504 */
3505static __always_inline void *
3506__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3507                   void *caller)
3508{
3509        unsigned long save_flags;
3510        void *ptr;
3511        int slab_node = numa_mem_id();
3512
3513        flags &= gfp_allowed_mask;
3514
3515        lockdep_trace_alloc(flags);
3516
3517        if (slab_should_failslab(cachep, flags))
3518                return NULL;
3519
3520        cache_alloc_debugcheck_before(cachep, flags);
3521        local_irq_save(save_flags);
3522
3523        if (nodeid == NUMA_NO_NODE)
3524                nodeid = slab_node;
3525
3526        if (unlikely(!cachep->nodelists[nodeid])) {
3527                /* Node not bootstrapped yet */
3528                ptr = fallback_alloc(cachep, flags);
3529                goto out;
3530        }
3531
3532        if (nodeid == slab_node) {
3533                /*
3534                 * Use the locally cached objects if possible.
3535                 * However ____cache_alloc does not allow fallback
3536                 * to other nodes. It may fail while we still have
3537                 * objects on other nodes available.
3538                 */
3539                ptr = ____cache_alloc(cachep, flags);
3540                if (ptr)
3541                        goto out;
3542        }
3543        /* ___cache_alloc_node can fall back to other nodes */
3544        ptr = ____cache_alloc_node(cachep, flags, nodeid);
3545  out:
3546        local_irq_restore(save_flags);
3547        ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3548        kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags,
3549                                 flags);
3550
3551        if (likely(ptr))
3552                kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep));
3553
3554        if (unlikely((flags & __GFP_ZERO) && ptr))
3555                memset(ptr, 0, obj_size(cachep));
3556
3557        return ptr;
3558}
3559
3560static __always_inline void *
3561__do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3562{
3563        void *objp;
3564
3565        if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
3566                objp = alternate_node_alloc(cache, flags);
3567                if (objp)
3568                        goto out;
3569        }
3570        objp = ____cache_alloc(cache, flags);
3571
3572        /*
3573         * We may just have run out of memory on the local node.
3574         * ____cache_alloc_node() knows how to locate memory on other nodes
3575         */
3576        if (!objp)
3577                objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3578
3579  out:
3580        return objp;
3581}
3582#else
3583
3584static __always_inline void *
3585__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3586{
3587        return ____cache_alloc(cachep, flags);
3588}
3589
3590#endif /* CONFIG_NUMA */
3591
3592static __always_inline void *
3593__cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller)
3594{
3595        unsigned long save_flags;
3596        void *objp;
3597
3598        flags &= gfp_allowed_mask;
3599
3600        lockdep_trace_alloc(flags);
3601
3602        if (slab_should_failslab(cachep, flags))
3603                return NULL;
3604
3605        cache_alloc_debugcheck_before(cachep, flags);
3606        local_irq_save(save_flags);
3607        objp = __do_cache_alloc(cachep, flags);
3608        local_irq_restore(save_flags);
3609        objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3610        kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags,
3611                                 flags);
3612        prefetchw(objp);
3613
3614        if (likely(objp))
3615                kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep));
3616
3617        if (unlikely((flags & __GFP_ZERO) && objp))
3618                memset(objp, 0, obj_size(cachep));
3619
3620        return objp;
3621}
3622
3623/*
3624 * Caller needs to acquire correct kmem_list's list_lock
3625 */
3626static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3627                       int node)
3628{
3629        int i;
3630        struct kmem_list3 *l3;
3631
3632        for (i = 0; i < nr_objects; i++) {
3633                void *objp = objpp[i];
3634                struct slab *slabp;
3635
3636                slabp = virt_to_slab(objp);
3637                l3 = cachep->nodelists[node];
3638                list_del(&slabp->list);
3639                check_spinlock_acquired_node(cachep, node);
3640                check_slabp(cachep, slabp);
3641                slab_put_obj(cachep, slabp, objp, node);
3642                STATS_DEC_ACTIVE(cachep);
3643                l3->free_objects++;
3644                check_slabp(cachep, slabp);
3645
3646                /* fixup slab chains */
3647                if (slabp->inuse == 0) {
3648                        if (l3->free_objects > l3->free_limit) {
3649                                l3->free_objects -= cachep->num;
3650                                /* No need to drop any previously held
3651                                 * lock here, even if we have a off-slab slab
3652                                 * descriptor it is guaranteed to come from
3653                                 * a different cache, refer to comments before
3654                                 * alloc_slabmgmt.
3655                                 */
3656                                slab_destroy(cachep, slabp);
3657                        } else {
3658                                list_add(&slabp->list, &l3->slabs_free);
3659                        }
3660                } else {
3661                        /* Unconditionally move a slab to the end of the
3662                         * partial list on free - maximum time for the
3663                         * other objects to be freed, too.
3664                         */
3665                        list_add_tail(&slabp->list, &l3->slabs_partial);
3666                }
3667        }
3668}
3669
3670static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3671{
3672        int batchcount;
3673        struct kmem_list3 *l3;
3674        int node = numa_mem_id();
3675
3676        batchcount = ac->batchcount;
3677#if DEBUG
3678        BUG_ON(!batchcount || batchcount > ac->avail);
3679#endif
3680        check_irq_off();
3681        l3 = cachep->nodelists[node];
3682        spin_lock(&l3->list_lock);
3683        if (l3->shared) {
3684                struct array_cache *shared_array = l3->shared;
3685                int max = shared_array->limit - shared_array->avail;
3686                if (max) {
3687                        if (batchcount > max)
3688                                batchcount = max;
3689                        memcpy(&(shared_array->entry[shared_array->avail]),
3690                               ac->entry, sizeof(void *) * batchcount);
3691                        shared_array->avail += batchcount;
3692                        goto free_done;
3693                }
3694        }
3695
3696        free_block(cachep, ac->entry, batchcount, node);
3697free_done:
3698#if STATS
3699        {
3700                int i = 0;
3701                struct list_head *p;
3702
3703                p = l3->slabs_free.next;
3704                while (p != &(l3->slabs_free)) {
3705                        struct slab *slabp;
3706
3707                        slabp = list_entry(p, struct slab, list);
3708                        BUG_ON(slabp->inuse);
3709
3710                        i++;
3711                        p = p->next;
3712                }
3713                STATS_SET_FREEABLE(cachep, i);
3714        }
3715#endif
3716        spin_unlock(&l3->list_lock);
3717        ac->avail -= batchcount;
3718        memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3719}
3720
3721/*
3722 * Release an obj back to its cache. If the obj has a constructed state, it must
3723 * be in this state _before_ it is released.  Called with disabled ints.
3724 */
3725static inline void __cache_free(struct kmem_cache *cachep, void *objp,
3726    void *caller)
3727{
3728        struct array_cache *ac = cpu_cache_get(cachep);
3729
3730        check_irq_off();
3731        kmemleak_free_recursive(objp, cachep->flags);
3732        objp = cache_free_debugcheck(cachep, objp, caller);
3733
3734        kmemcheck_slab_free(cachep, objp, obj_size(cachep));
3735
3736        /*
3737         * Skip calling cache_free_alien() when the platform is not numa.
3738         * This will avoid cache misses that happen while accessing slabp (which
3739         * is per page memory  reference) to get nodeid. Instead use a global
3740         * variable to skip the call, which is mostly likely to be present in
3741         * the cache.
3742         */
3743        if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3744                return;
3745
3746        if (likely(ac->avail < ac->limit)) {
3747                STATS_INC_FREEHIT(cachep);
3748        } else {
3749                STATS_INC_FREEMISS(cachep);
3750                cache_flusharray(cachep, ac);
3751        }
3752
3753        ac->entry[ac->avail++] = objp;
3754}
3755
3756/**
3757 * kmem_cache_alloc - Allocate an object
3758 * @cachep: The cache to allocate from.
3759 * @flags: See kmalloc().
3760 *
3761 * Allocate an object from this cache.  The flags are only relevant
3762 * if the cache has no available objects.
3763 */
3764void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3765{
3766        void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
3767
3768        trace_kmem_cache_alloc(_RET_IP_, ret,
3769                               obj_size(cachep), cachep->buffer_size, flags);
3770
3771        return ret;
3772}
3773EXPORT_SYMBOL(kmem_cache_alloc);
3774
3775#ifdef CONFIG_TRACING
3776void *
3777kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags)
3778{
3779        void *ret;
3780
3781        ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
3782
3783        trace_kmalloc(_RET_IP_, ret,
3784                      size, slab_buffer_size(cachep), flags);
3785        return ret;
3786}
3787EXPORT_SYMBOL(kmem_cache_alloc_trace);
3788#endif
3789
3790#ifdef CONFIG_NUMA
3791void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3792{
3793        void *ret = __cache_alloc_node(cachep, flags, nodeid,
3794                                       __builtin_return_address(0));
3795
3796        trace_kmem_cache_alloc_node(_RET_IP_, ret,
3797                                    obj_size(cachep), cachep->buffer_size,
3798                                    flags, nodeid);
3799
3800        return ret;
3801}
3802EXPORT_SYMBOL(kmem_cache_alloc_node);
3803
3804#ifdef CONFIG_TRACING
3805void *kmem_cache_alloc_node_trace(size_t size,
3806                                  struct kmem_cache *cachep,
3807                                  gfp_t flags,
3808                                  int nodeid)
3809{
3810        void *ret;
3811
3812        ret = __cache_alloc_node(cachep, flags, nodeid,
3813                                  __builtin_return_address(0));
3814        trace_kmalloc_node(_RET_IP_, ret,
3815                           size, slab_buffer_size(cachep),
3816                           flags, nodeid);
3817        return ret;
3818}
3819EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3820#endif
3821
3822static __always_inline void *
3823__do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller)
3824{
3825        struct kmem_cache *cachep;
3826
3827        cachep = kmem_find_general_cachep(size, flags);
3828        if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3829                return cachep;
3830        return kmem_cache_alloc_node_trace(size, cachep, flags, node);
3831}
3832
3833#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3834void *__kmalloc_node(size_t size, gfp_t flags, int node)
3835{
3836        return __do_kmalloc_node(size, flags, node,
3837                        __builtin_return_address(0));
3838}
3839EXPORT_SYMBOL(__kmalloc_node);
3840
3841void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3842                int node, unsigned long caller)
3843{
3844        return __do_kmalloc_node(size, flags, node, (void *)caller);
3845}
3846EXPORT_SYMBOL(__kmalloc_node_track_caller);
3847#else
3848void *__kmalloc_node(size_t size, gfp_t flags, int node)
3849{
3850        return __do_kmalloc_node(size, flags, node, NULL);
3851}
3852EXPORT_SYMBOL(__kmalloc_node);
3853#endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
3854#endif /* CONFIG_NUMA */
3855
3856/**
3857 * __do_kmalloc - allocate memory
3858 * @size: how many bytes of memory are required.
3859 * @flags: the type of memory to allocate (see kmalloc).
3860 * @caller: function caller for debug tracking of the caller
3861 */
3862static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3863                                          void *caller)
3864{
3865        struct kmem_cache *cachep;
3866        void *ret;
3867
3868        /* If you want to save a few bytes .text space: replace
3869         * __ with kmem_.
3870         * Then kmalloc uses the uninlined functions instead of the inline
3871         * functions.
3872         */
3873        cachep = __find_general_cachep(size, flags);
3874        if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3875                return cachep;
3876        ret = __cache_alloc(cachep, flags, caller);
3877
3878        trace_kmalloc((unsigned long) caller, ret,
3879                      size, cachep->buffer_size, flags);
3880
3881        return ret;
3882}
3883
3884
3885#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3886void *__kmalloc(size_t size, gfp_t flags)
3887{
3888        return __do_kmalloc(size, flags, __builtin_return_address(0));
3889}
3890EXPORT_SYMBOL(__kmalloc);
3891
3892void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3893{
3894        return __do_kmalloc(size, flags, (void *)caller);
3895}
3896EXPORT_SYMBOL(__kmalloc_track_caller);
3897
3898#else
3899void *__kmalloc(size_t size, gfp_t flags)
3900{
3901        return __do_kmalloc(size, flags, NULL);
3902}
3903EXPORT_SYMBOL(__kmalloc);
3904#endif
3905
3906/**
3907 * kmem_cache_free - Deallocate an object
3908 * @cachep: The cache the allocation was from.
3909 * @objp: The previously allocated object.
3910 *
3911 * Free an object which was previously allocated from this
3912 * cache.
3913 */
3914void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3915{
3916        unsigned long flags;
3917
3918        local_irq_save(flags);
3919        debug_check_no_locks_freed(objp, obj_size(cachep));
3920        if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3921                debug_check_no_obj_freed(objp, obj_size(cachep));
3922        __cache_free(cachep, objp, __builtin_return_address(0));
3923        local_irq_restore(flags);
3924
3925        trace_kmem_cache_free(_RET_IP_, objp);
3926}
3927EXPORT_SYMBOL(kmem_cache_free);
3928
3929/**
3930 * kfree - free previously allocated memory
3931 * @objp: pointer returned by kmalloc.
3932 *
3933 * If @objp is NULL, no operation is performed.
3934 *
3935 * Don't free memory not originally allocated by kmalloc()
3936 * or you will run into trouble.
3937 */
3938void kfree(const void *objp)
3939{
3940        struct kmem_cache *c;
3941        unsigned long flags;
3942
3943        trace_kfree(_RET_IP_, objp);
3944
3945        if (unlikely(ZERO_OR_NULL_PTR(objp)))
3946                return;
3947        local_irq_save(flags);
3948        kfree_debugcheck(objp);
3949        c = virt_to_cache(objp);
3950        debug_check_no_locks_freed(objp, obj_size(c));
3951        debug_check_no_obj_freed(objp, obj_size(c));
3952        __cache_free(c, (void *)objp, __builtin_return_address(0));
3953        local_irq_restore(flags);
3954}
3955EXPORT_SYMBOL(kfree);
3956
3957unsigned int kmem_cache_size(struct kmem_cache *cachep)
3958{
3959        return obj_size(cachep);
3960}
3961EXPORT_SYMBOL(kmem_cache_size);
3962
3963/*
3964 * This initializes kmem_list3 or resizes various caches for all nodes.
3965 */
3966static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
3967{
3968        int node;
3969        struct kmem_list3 *l3;
3970        struct array_cache *new_shared;
3971        struct array_cache **new_alien = NULL;
3972
3973        for_each_online_node(node) {
3974
3975                if (use_alien_caches) {
3976                        new_alien = alloc_alien_cache(node, cachep->limit, gfp);
3977                        if (!new_alien)
3978                                goto fail;
3979                }
3980
3981                new_shared = NULL;
3982                if (cachep->shared) {
3983                        new_shared = alloc_arraycache(node,
3984                                cachep->shared*cachep->batchcount,
3985                                        0xbaadf00d, gfp);
3986                        if (!new_shared) {
3987                                free_alien_cache(new_alien);
3988                                goto fail;
3989                        }
3990                }
3991
3992                l3 = cachep->nodelists[node];
3993                if (l3) {
3994                        struct array_cache *shared = l3->shared;
3995
3996                        spin_lock_irq(&l3->list_lock);
3997
3998                        if (shared)
3999                                free_block(cachep, shared->entry,
4000                                                shared->avail, node);
4001
4002                        l3->shared = new_shared;
4003                        if (!l3->alien) {
4004                                l3->alien = new_alien;
4005                                new_alien = NULL;
4006                        }
4007                        l3->free_limit = (1 + nr_cpus_node(node)) *
4008                                        cachep->batchcount + cachep->num;
4009                        spin_unlock_irq(&l3->list_lock);
4010                        kfree(shared);
4011                        free_alien_cache(new_alien);
4012                        continue;
4013                }
4014                l3 = kmalloc_node(sizeof(struct kmem_list3), gfp, node);
4015                if (!l3) {
4016                        free_alien_cache(new_alien);
4017                        kfree(new_shared);
4018                        goto fail;
4019                }
4020
4021                kmem_list3_init(l3);
4022                l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
4023                                ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
4024                l3->shared = new_shared;
4025                l3->alien = new_alien;
4026                l3->free_limit = (1 + nr_cpus_node(node)) *
4027                                        cachep->batchcount + cachep->num;
4028                cachep->nodelists[node] = l3;
4029        }
4030        return 0;
4031
4032fail:
4033        if (!cachep->next.next) {
4034                /* Cache is not active yet. Roll back what we did */
4035                node--;
4036                while (node >= 0) {
4037                        if (cachep->nodelists[node]) {
4038                                l3 = cachep->nodelists[node];
4039
4040                                kfree(l3->shared);
4041                                free_alien_cache(l3->alien);
4042                                kfree(l3);
4043                                cachep->nodelists[node] = NULL;
4044                        }
4045                        node--;
4046                }
4047        }
4048        return -ENOMEM;
4049}
4050
4051struct ccupdate_struct {
4052        struct kmem_cache *cachep;
4053        struct array_cache *new[0];
4054};
4055
4056static void do_ccupdate_local(void *info)
4057{
4058        struct ccupdate_struct *new = info;
4059        struct array_cache *old;
4060
4061        check_irq_off();
4062        old = cpu_cache_get(new->cachep);
4063
4064        new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
4065        new->new[smp_processor_id()] = old;
4066}
4067
4068/* Always called with the cache_chain_mutex held */
4069static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
4070                                int batchcount, int shared, gfp_t gfp)
4071{
4072        struct ccupdate_struct *new;
4073        int i;
4074
4075        new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *),
4076                      gfp);
4077        if (!new)
4078                return -ENOMEM;
4079
4080        for_each_online_cpu(i) {
4081                new->new[i] = alloc_arraycache(cpu_to_mem(i), limit,
4082                                                batchcount, gfp);
4083                if (!new->new[i]) {
4084                        for (i--; i >= 0; i--)
4085                                kfree(new->new[i]);
4086                        kfree(new);
4087                        return -ENOMEM;
4088                }
4089        }
4090        new->cachep = cachep;
4091
4092        on_each_cpu(do_ccupdate_local, (void *)new, 1);
4093
4094        check_irq_on();
4095        cachep->batchcount = batchcount;
4096        cachep->limit = limit;
4097        cachep->shared = shared;
4098
4099        for_each_online_cpu(i) {
4100                struct array_cache *ccold = new->new[i];
4101                if (!ccold)
4102                        continue;
4103                spin_lock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
4104                free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i));
4105                spin_unlock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
4106                kfree(ccold);
4107        }
4108        kfree(new);
4109        return alloc_kmemlist(cachep, gfp);
4110}
4111
4112/* Called with cache_chain_mutex held always */
4113static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
4114{
4115        int err;
4116        int limit, shared;
4117
4118        /*
4119         * The head array serves three purposes:
4120         * - create a LIFO ordering, i.e. return objects that are cache-warm
4121         * - reduce the number of spinlock operations.
4122         * - reduce the number of linked list operations on the slab and
4123         *   bufctl chains: array operations are cheaper.
4124         * The numbers are guessed, we should auto-tune as described by
4125         * Bonwick.
4126         */
4127        if (cachep->buffer_size > 131072)
4128                limit = 1;
4129        else if (cachep->buffer_size > PAGE_SIZE)
4130                limit = 8;
4131        else if (cachep->buffer_size > 1024)
4132                limit = 24;
4133        else if (cachep->buffer_size > 256)
4134                limit = 54;
4135        else
4136                limit = 120;
4137
4138        /*
4139         * CPU bound tasks (e.g. network routing) can exhibit cpu bound
4140         * allocation behaviour: Most allocs on one cpu, most free operations
4141         * on another cpu. For these cases, an efficient object passing between
4142         * cpus is necessary. This is provided by a shared array. The array
4143         * replaces Bonwick's magazine layer.
4144         * On uniprocessor, it's functionally equivalent (but less efficient)
4145         * to a larger limit. Thus disabled by default.
4146         */
4147        shared = 0;
4148        if (cachep->buffer_size <= PAGE_SIZE && num_possible_cpus() > 1)
4149                shared = 8;
4150
4151#if DEBUG
4152        /*
4153         * With debugging enabled, large batchcount lead to excessively long
4154         * periods with disabled local interrupts. Limit the batchcount
4155         */
4156        if (limit > 32)
4157                limit = 32;
4158#endif
4159        err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared, gfp);
4160        if (err)
4161                printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
4162                       cachep->name, -err);
4163        return err;
4164}
4165
4166/*
4167 * Drain an array if it contains any elements taking the l3 lock only if
4168 * necessary. Note that the l3 listlock also protects the array_cache
4169 * if drain_array() is used on the shared array.
4170 */
4171static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
4172                         struct array_cache *ac, int force, int node)
4173{
4174        int tofree;
4175
4176        if (!ac || !ac->avail)
4177                return;
4178        if (ac->touched && !force) {
4179                ac->touched = 0;
4180        } else {
4181                spin_lock_irq(&l3->list_lock);
4182                if (ac->avail) {
4183                        tofree = force ? ac->avail : (ac->limit + 4) / 5;
4184                        if (tofree > ac->avail)
4185                                tofree = (ac->avail + 1) / 2;
4186                        free_block(cachep, ac->entry, tofree, node);
4187                        ac->avail -= tofree;
4188                        memmove(ac->entry, &(ac->entry[tofree]),
4189                                sizeof(void *) * ac->avail);
4190                }
4191                spin_unlock_irq(&l3->list_lock);
4192        }
4193}
4194
4195/**
4196 * cache_reap - Reclaim memory from caches.
4197 * @w: work descriptor
4198 *
4199 * Called from workqueue/eventd every few seconds.
4200 * Purpose:
4201 * - clear the per-cpu caches for this CPU.
4202 * - return freeable pages to the main free memory pool.
4203 *
4204 * If we cannot acquire the cache chain mutex then just give up - we'll try
4205 * again on the next iteration.
4206 */
4207static void cache_reap(struct work_struct *w)
4208{
4209        struct kmem_cache *searchp;
4210        struct kmem_list3 *l3;
4211        int node = numa_mem_id();
4212        struct delayed_work *work = to_delayed_work(w);
4213
4214        if (!mutex_trylock(&cache_chain_mutex))
4215                /* Give up. Setup the next iteration. */
4216                goto out;
4217
4218        list_for_each_entry(searchp, &cache_chain, next) {
4219                check_irq_on();
4220
4221                /*
4222                 * We only take the l3 lock if absolutely necessary and we
4223                 * have established with reasonable certainty that
4224                 * we can do some work if the lock was obtained.
4225                 */
4226                l3 = searchp->nodelists[node];
4227
4228                reap_alien(searchp, l3);
4229
4230                drain_array(searchp, l3, cpu_cache_get(searchp), 0, node);
4231
4232                /*
4233                 * These are racy checks but it does not matter
4234                 * if we skip one check or scan twice.
4235                 */
4236                if (time_after(l3->next_reap, jiffies))
4237                        goto next;
4238
4239                l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
4240
4241                drain_array(searchp, l3, l3->shared, 0, node);
4242
4243                if (l3->free_touched)
4244                        l3->free_touched = 0;
4245                else {
4246                        int freed;
4247
4248                        freed = drain_freelist(searchp, l3, (l3->free_limit +
4249                                5 * searchp->num - 1) / (5 * searchp->num));
4250                        STATS_ADD_REAPED(searchp, freed);
4251                }
4252next:
4253                cond_resched();
4254        }
4255        check_irq_on();
4256        mutex_unlock(&cache_chain_mutex);
4257        next_reap_node();
4258out:
4259        /* Set up the next iteration */
4260        schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
4261}
4262
4263#ifdef CONFIG_SLABINFO
4264
4265static void print_slabinfo_header(struct seq_file *m)
4266{
4267        /*
4268         * Output format version, so at least we can change it
4269         * without _too_ many complaints.
4270         */
4271#if STATS
4272        seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
4273#else
4274        seq_puts(m, "slabinfo - version: 2.1\n");
4275#endif
4276        seq_puts(m, "# name            <active_objs> <num_objs> <objsize> "
4277                 "<objperslab> <pagesperslab>");
4278        seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
4279        seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4280#if STATS
4281        seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
4282                 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
4283        seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
4284#endif
4285        seq_putc(m, '\n');
4286}
4287
4288static void *s_start(struct seq_file *m, loff_t *pos)
4289{
4290        loff_t n = *pos;
4291
4292        mutex_lock(&cache_chain_mutex);
4293        if (!n)
4294                print_slabinfo_header(m);
4295
4296        return seq_list_start(&cache_chain, *pos);
4297}
4298
4299static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4300{
4301        return seq_list_next(p, &cache_chain, pos);
4302}
4303
4304static void s_stop(struct seq_file *m, void *p)
4305{
4306        mutex_unlock(&cache_chain_mutex);
4307}
4308
4309static int s_show(struct seq_file *m, void *p)
4310{
4311        struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
4312        struct slab *slabp;
4313        unsigned long active_objs;
4314        unsigned long num_objs;
4315        unsigned long active_slabs = 0;
4316        unsigned long num_slabs, free_objects = 0, shared_avail = 0;
4317        const char *name;
4318        char *error = NULL;
4319        int node;
4320        struct kmem_list3 *l3;
4321
4322        active_objs = 0;
4323        num_slabs = 0;
4324        for_each_online_node(node) {
4325                l3 = cachep->nodelists[node];
4326                if (!l3)
4327                        continue;
4328
4329                check_irq_on();
4330                spin_lock_irq(&l3->list_lock);
4331
4332                list_for_each_entry(slabp, &l3->slabs_full, list) {
4333                        if (slabp->inuse != cachep->num && !error)
4334                                error = "slabs_full accounting error";
4335                        active_objs += cachep->num;
4336                        active_slabs++;
4337                }
4338                list_for_each_entry(slabp, &l3->slabs_partial, list) {
4339                        if (slabp->inuse == cachep->num && !error)
4340                                error = "slabs_partial inuse accounting error";
4341                        if (!slabp->inuse && !error)
4342                                error = "slabs_partial/inuse accounting error";
4343                        active_objs += slabp->inuse;
4344                        active_slabs++;
4345                }
4346                list_for_each_entry(slabp, &l3->slabs_free, list) {
4347                        if (slabp->inuse && !error)
4348                                error = "slabs_free/inuse accounting error";
4349                        num_slabs++;
4350                }
4351                free_objects += l3->free_objects;
4352                if (l3->shared)
4353                        shared_avail += l3->shared->avail;
4354
4355                spin_unlock_irq(&l3->list_lock);
4356        }
4357        num_slabs += active_slabs;
4358        num_objs = num_slabs * cachep->num;
4359        if (num_objs - active_objs != free_objects && !error)
4360                error = "free_objects accounting error";
4361
4362        name = cachep->name;
4363        if (error)
4364                printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
4365
4366        seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
4367                   name, active_objs, num_objs, cachep->buffer_size,
4368                   cachep->num, (1 << cachep->gfporder));
4369        seq_printf(m, " : tunables %4u %4u %4u",
4370                   cachep->limit, cachep->batchcount, cachep->shared);
4371        seq_printf(m, " : slabdata %6lu %6lu %6lu",
4372                   active_slabs, num_slabs, shared_avail);
4373#if STATS
4374        {                       /* list3 stats */
4375                unsigned long high = cachep->high_mark;
4376                unsigned long allocs = cachep->num_allocations;
4377                unsigned long grown = cachep->grown;
4378                unsigned long reaped = cachep->reaped;
4379                unsigned long errors = cachep->errors;
4380                unsigned long max_freeable = cachep->max_freeable;
4381                unsigned long node_allocs = cachep->node_allocs;
4382                unsigned long node_frees = cachep->node_frees;
4383                unsigned long overflows = cachep->node_overflow;
4384
4385                seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu "
4386                           "%4lu %4lu %4lu %4lu %4lu",
4387                           allocs, high, grown,
4388                           reaped, errors, max_freeable, node_allocs,
4389                           node_frees, overflows);
4390        }
4391        /* cpu stats */
4392        {
4393                unsigned long allochit = atomic_read(&cachep->allochit);
4394                unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4395                unsigned long freehit = atomic_read(&cachep->freehit);
4396                unsigned long freemiss = atomic_read(&cachep->freemiss);
4397
4398                seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4399                           allochit, allocmiss, freehit, freemiss);
4400        }
4401#endif
4402        seq_putc(m, '\n');
4403        return 0;
4404}
4405
4406/*
4407 * slabinfo_op - iterator that generates /proc/slabinfo
4408 *
4409 * Output layout:
4410 * cache-name
4411 * num-active-objs
4412 * total-objs
4413 * object size
4414 * num-active-slabs
4415 * total-slabs
4416 * num-pages-per-slab
4417 * + further values on SMP and with statistics enabled
4418 */
4419
4420static const struct seq_operations slabinfo_op = {
4421        .start = s_start,
4422        .next = s_next,
4423        .stop = s_stop,
4424        .show = s_show,
4425};
4426
4427#define MAX_SLABINFO_WRITE 128
4428/**
4429 * slabinfo_write - Tuning for the slab allocator
4430 * @file: unused
4431 * @buffer: user buffer
4432 * @count: data length
4433 * @ppos: unused
4434 */
4435static ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4436                       size_t count, loff_t *ppos)
4437{
4438        char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4439        int limit, batchcount, shared, res;
4440        struct kmem_cache *cachep;
4441
4442        if (count > MAX_SLABINFO_WRITE)
4443                return -EINVAL;
4444        if (copy_from_user(&kbuf, buffer, count))
4445                return -EFAULT;
4446        kbuf[MAX_SLABINFO_WRITE] = '\0';
4447
4448        tmp = strchr(kbuf, ' ');
4449        if (!tmp)
4450                return -EINVAL;
4451        *tmp = '\0';
4452        tmp++;
4453        if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4454                return -EINVAL;
4455
4456        /* Find the cache in the chain of caches. */
4457        mutex_lock(&cache_chain_mutex);
4458        res = -EINVAL;
4459        list_for_each_entry(cachep, &cache_chain, next) {
4460                if (!strcmp(cachep->name, kbuf)) {
4461                        if (limit < 1 || batchcount < 1 ||
4462                                        batchcount > limit || shared < 0) {
4463                                res = 0;
4464                        } else {
4465                                res = do_tune_cpucache(cachep, limit,
4466                                                       batchcount, shared,
4467                                                       GFP_KERNEL);
4468                        }
4469                        break;
4470                }
4471        }
4472        mutex_unlock(&cache_chain_mutex);
4473        if (res >= 0)
4474                res = count;
4475        return res;
4476}
4477
4478static int slabinfo_open(struct inode *inode, struct file *file)
4479{
4480        return seq_open(file, &slabinfo_op);
4481}
4482
4483static const struct file_operations proc_slabinfo_operations = {
4484        .open           = slabinfo_open,
4485        .read           = seq_read,
4486        .write          = slabinfo_write,
4487        .llseek         = seq_lseek,
4488        .release        = seq_release,
4489};
4490
4491#ifdef CONFIG_DEBUG_SLAB_LEAK
4492
4493static void *leaks_start(struct seq_file *m, loff_t *pos)
4494{
4495        mutex_lock(&cache_chain_mutex);
4496        return seq_list_start(&cache_chain, *pos);
4497}
4498
4499static inline int add_caller(unsigned long *n, unsigned long v)
4500{
4501        unsigned long *p;
4502        int l;
4503        if (!v)
4504                return 1;
4505        l = n[1];
4506        p = n + 2;
4507        while (l) {
4508                int i = l/2;
4509                unsigned long *q = p + 2 * i;
4510                if (*q == v) {
4511                        q[1]++;
4512                        return 1;
4513                }
4514                if (*q > v) {
4515                        l = i;
4516                } else {
4517                        p = q + 2;
4518                        l -= i + 1;
4519                }
4520        }
4521        if (++n[1] == n[0])
4522                return 0;
4523        memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4524        p[0] = v;
4525        p[1] = 1;
4526        return 1;
4527}
4528
4529static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
4530{
4531        void *p;
4532        int i;
4533        if (n[0] == n[1])
4534                return;
4535        for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) {
4536                if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
4537                        continue;
4538                if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4539                        return;
4540        }
4541}
4542
4543static void show_symbol(struct seq_file *m, unsigned long address)
4544{
4545#ifdef CONFIG_KALLSYMS
4546        unsigned long offset, size;
4547        char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4548
4549        if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4550                seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4551                if (modname[0])
4552                        seq_printf(m, " [%s]", modname);
4553                return;
4554        }
4555#endif
4556        seq_printf(m, "%p", (void *)address);
4557}
4558
4559static int leaks_show(struct seq_file *m, void *p)
4560{
4561        struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
4562        struct slab *slabp;
4563        struct kmem_list3 *l3;
4564        const char *name;
4565        unsigned long *n = m->private;
4566        int node;
4567        int i;
4568
4569        if (!(cachep->flags & SLAB_STORE_USER))
4570                return 0;
4571        if (!(cachep->flags & SLAB_RED_ZONE))
4572                return 0;
4573
4574        /* OK, we can do it */
4575
4576        n[1] = 0;
4577
4578        for_each_online_node(node) {
4579                l3 = cachep->nodelists[node];
4580                if (!l3)
4581                        continue;
4582
4583                check_irq_on();
4584                spin_lock_irq(&l3->list_lock);
4585
4586                list_for_each_entry(slabp, &l3->slabs_full, list)
4587                        handle_slab(n, cachep, slabp);
4588                list_for_each_entry(slabp, &l3->slabs_partial, list)
4589                        handle_slab(n, cachep, slabp);
4590                spin_unlock_irq(&l3->list_lock);
4591        }
4592        name = cachep->name;
4593        if (n[0] == n[1]) {
4594                /* Increase the buffer size */
4595                mutex_unlock(&cache_chain_mutex);
4596                m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4597                if (!m->private) {
4598                        /* Too bad, we are really out */
4599                        m->private = n;
4600                        mutex_lock(&cache_chain_mutex);
4601                        return -ENOMEM;
4602                }
4603                *(unsigned long *)m->private = n[0] * 2;
4604                kfree(n);
4605                mutex_lock(&cache_chain_mutex);
4606                /* Now make sure this entry will be retried */
4607                m->count = m->size;
4608                return 0;
4609        }
4610        for (i = 0; i < n[1]; i++) {
4611                seq_printf(m, "%s: %lu ", name, n[2*i+3]);
4612                show_symbol(m, n[2*i+2]);
4613                seq_putc(m, '\n');
4614        }
4615
4616        return 0;
4617}
4618
4619static const struct seq_operations slabstats_op = {
4620        .start = leaks_start,
4621        .next = s_next,
4622        .stop = s_stop,
4623        .show = leaks_show,
4624};
4625
4626static int slabstats_open(struct inode *inode, struct file *file)
4627{
4628        unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
4629        int ret = -ENOMEM;
4630        if (n) {
4631                ret = seq_open(file, &slabstats_op);
4632                if (!ret) {
4633                        struct seq_file *m = file->private_data;
4634                        *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4635                        m->private = n;
4636                        n = NULL;
4637                }
4638                kfree(n);
4639        }
4640        return ret;
4641}
4642
4643static const struct file_operations proc_slabstats_operations = {
4644        .open           = slabstats_open,
4645        .read           = seq_read,
4646        .llseek         = seq_lseek,
4647        .release        = seq_release_private,
4648};
4649#endif
4650
4651static int __init slab_proc_init(void)
4652{
4653        proc_create("slabinfo",S_IWUSR|S_IRUSR,NULL,&proc_slabinfo_operations);
4654#ifdef CONFIG_DEBUG_SLAB_LEAK
4655        proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4656#endif
4657        return 0;
4658}
4659module_init(slab_proc_init);
4660#endif
4661
4662/**
4663 * ksize - get the actual amount of memory allocated for a given object
4664 * @objp: Pointer to the object
4665 *
4666 * kmalloc may internally round up allocations and return more memory
4667 * than requested. ksize() can be used to determine the actual amount of
4668 * memory allocated. The caller may use this additional memory, even though
4669 * a smaller amount of memory was initially specified with the kmalloc call.
4670 * The caller must guarantee that objp points to a valid object previously
4671 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4672 * must not be freed during the duration of the call.
4673 */
4674size_t ksize(const void *objp)
4675{
4676        BUG_ON(!objp);
4677        if (unlikely(objp == ZERO_SIZE_PTR))
4678                return 0;
4679
4680        return obj_size(virt_to_cache(objp));
4681}
4682EXPORT_SYMBOL(ksize);
4683
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