include/linux/slab.h

   1 /*
   2  * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
   3  *
   4  * (C) SGI 2006, Christoph Lameter
   5  *      Cleaned up and restructured to ease the addition of alternative
   6  *      implementations of SLAB allocators.
   7  * (C) Linux Foundation 2008-2013
   8  *      Unified interface for all slab allocators
   9  */
  10
  11 #ifndef _LINUX_SLAB_H
  12 #define _LINUX_SLAB_H
  13
  14 #include <linux/gfp.h>
  15 #include <linux/types.h>
  16 #include <linux/workqueue.h>
  17
  18
  19 /*
  20  * Flags to pass to kmem_cache_create().
  21  * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
  22  */
  23 #define SLAB_CONSISTENCY_CHECKS 0x00000100UL    /* DEBUG: Perform (expensive) checks on alloc/free */
  24 #define SLAB_RED_ZONE           0x00000400UL    /* DEBUG: Red zone objs in a cache */
  25 #define SLAB_POISON             0x00000800UL    /* DEBUG: Poison objects */
  26 #define SLAB_HWCACHE_ALIGN      0x00002000UL    /* Align objs on cache lines */
  27 #define SLAB_CACHE_DMA          0x00004000UL    /* Use GFP_DMA memory */
  28 #define SLAB_STORE_USER         0x00010000UL    /* DEBUG: Store the last owner for bug hunting */
  29 #define SLAB_PANIC              0x00040000UL    /* Panic if kmem_cache_create() fails */
  30 /*
  31  * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
  32  *
  33  * This delays freeing the SLAB page by a grace period, it does _NOT_
  34  * delay object freeing. This means that if you do kmem_cache_free()
  35  * that memory location is free to be reused at any time. Thus it may
  36  * be possible to see another object there in the same RCU grace period.
  37  *
  38  * This feature only ensures the memory location backing the object
  39  * stays valid, the trick to using this is relying on an independent
  40  * object validation pass. Something like:
  41  *
  42  *  rcu_read_lock()
  43  * again:
  44  *  obj = lockless_lookup(key);
  45  *  if (obj) {
  46  *    if (!try_get_ref(obj)) // might fail for free objects
  47  *      goto again;
  48  *
  49  *    if (obj->key != key) { // not the object we expected
  50  *      put_ref(obj);
  51  *      goto again;
  52  *    }
  53  *  }
  54  *  rcu_read_unlock();
  55  *
  56  * This is useful if we need to approach a kernel structure obliquely,
  57  * from its address obtained without the usual locking. We can lock
  58  * the structure to stabilize it and check it's still at the given address,
  59  * only if we can be sure that the memory has not been meanwhile reused
  60  * for some other kind of object (which our subsystem's lock might corrupt).
  61  *
  62  * rcu_read_lock before reading the address, then rcu_read_unlock after
  63  * taking the spinlock within the structure expected at that address.
  64  *
  65  * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
  66  */
  67 #define SLAB_TYPESAFE_BY_RCU    0x00080000UL    /* Defer freeing slabs to RCU */
  68 #define SLAB_MEM_SPREAD         0x00100000UL    /* Spread some memory over cpuset */
  69 #define SLAB_TRACE              0x00200000UL    /* Trace allocations and frees */
  70
  71 /* Flag to prevent checks on free */
  72 #ifdef CONFIG_DEBUG_OBJECTS
  73 # define SLAB_DEBUG_OBJECTS     0x00400000UL
  74 #else
  75 # define SLAB_DEBUG_OBJECTS     0x00000000UL
  76 #endif
  77
  78 #define SLAB_NOLEAKTRACE        0x00800000UL    /* Avoid kmemleak tracing */
  79
  80 /* Don't track use of uninitialized memory */
  81 #ifdef CONFIG_KMEMCHECK
  82 # define SLAB_NOTRACK           0x01000000UL
  83 #else
  84 # define SLAB_NOTRACK           0x00000000UL
  85 #endif
  86 #ifdef CONFIG_FAILSLAB
  87 # define SLAB_FAILSLAB          0x02000000UL    /* Fault injection mark */
  88 #else
  89 # define SLAB_FAILSLAB          0x00000000UL
  90 #endif
  91 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
  92 # define SLAB_ACCOUNT           0x04000000UL    /* Account to memcg */
  93 #else
  94 # define SLAB_ACCOUNT           0x00000000UL
  95 #endif
  96
  97 #ifdef CONFIG_KASAN
  98 #define SLAB_KASAN              0x08000000UL
  99 #else
 100 #define SLAB_KASAN              0x00000000UL
 101 #endif
 102
 103 /* The following flags affect the page allocator grouping pages by mobility */
 104 #define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
 105 #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
 106 /*
 107  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
 108  *
 109  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
 110  *
 111  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
 112  * Both make kfree a no-op.
 113  */
 114 #define ZERO_SIZE_PTR ((void *)16)
 115
 116 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
 117                                 (unsigned long)ZERO_SIZE_PTR)
 118
 119 #include <linux/kmemleak.h>
 120 #include <linux/kasan.h>
 121
 122 struct mem_cgroup;
 123 /*
 124  * struct kmem_cache related prototypes
 125  */
 126 void __init kmem_cache_init(void);
 127 bool slab_is_available(void);
 128
 129 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
 130                         unsigned long,
 131                         void (*)(void *));
 132 void kmem_cache_destroy(struct kmem_cache *);
 133 int kmem_cache_shrink(struct kmem_cache *);
 134
 135 void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *);
 136 void memcg_deactivate_kmem_caches(struct mem_cgroup *);
 137 void memcg_destroy_kmem_caches(struct mem_cgroup *);
 138
 139 /*
 140  * Please use this macro to create slab caches. Simply specify the
 141  * name of the structure and maybe some flags that are listed above.
 142  *
 143  * The alignment of the struct determines object alignment. If you
 144  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
 145  * then the objects will be properly aligned in SMP configurations.
 146  */
 147 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
 148                 sizeof(struct __struct), __alignof__(struct __struct),\
 149                 (__flags), NULL)
 150
 151 /*
 152  * Common kmalloc functions provided by all allocators
 153  */
 154 void * __must_check __krealloc(const void *, size_t, gfp_t);
 155 void * __must_check krealloc(const void *, size_t, gfp_t);
 156 void kfree(const void *);
 157 void kzfree(const void *);
 158 size_t ksize(const void *);
 159
 160 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
 161 const char *__check_heap_object(const void *ptr, unsigned long n,
 162                                 struct page *page);
 163 #else
 164 static inline const char *__check_heap_object(const void *ptr,
 165                                               unsigned long n,
 166                                               struct page *page)
 167 {
 168         return NULL;
 169 }
 170 #endif
 171
 172 /*
 173  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
 174  * alignment larger than the alignment of a 64-bit integer.
 175  * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
 176  */
 177 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 178 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
 179 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 180 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
 181 #else
 182 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
 183 #endif
 184
 185 /*
 186  * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
 187  * Intended for arches that get misalignment faults even for 64 bit integer
 188  * aligned buffers.
 189  */
 190 #ifndef ARCH_SLAB_MINALIGN
 191 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 192 #endif
 193
 194 /*
 195  * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
 196  * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
 197  * aligned pointers.
 198  */
 199 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
 200 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
 201 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
 202
 203 /*
 204  * Kmalloc array related definitions
 205  */
 206
 207 #ifdef CONFIG_SLAB
 208 /*
 209  * The largest kmalloc size supported by the SLAB allocators is
 210  * 32 megabyte (2^25) or the maximum allocatable page order if that is
 211  * less than 32 MB.
 212  *
 213  * WARNING: Its not easy to increase this value since the allocators have
 214  * to do various tricks to work around compiler limitations in order to
 215  * ensure proper constant folding.
 216  */
 217 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
 218                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
 219 #define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
 220 #ifndef KMALLOC_SHIFT_LOW
 221 #define KMALLOC_SHIFT_LOW       5
 222 #endif
 223 #endif
 224
 225 #ifdef CONFIG_SLUB
 226 /*
 227  * SLUB directly allocates requests fitting in to an order-1 page
 228  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
 229  */
 230 #define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
 231 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
 232 #ifndef KMALLOC_SHIFT_LOW
 233 #define KMALLOC_SHIFT_LOW       3
 234 #endif
 235 #endif
 236
 237 #ifdef CONFIG_SLOB
 238 /*
 239  * SLOB passes all requests larger than one page to the page allocator.
 240  * No kmalloc array is necessary since objects of different sizes can
 241  * be allocated from the same page.
 242  */
 243 #define KMALLOC_SHIFT_HIGH      PAGE_SHIFT
 244 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
 245 #ifndef KMALLOC_SHIFT_LOW
 246 #define KMALLOC_SHIFT_LOW       3
 247 #endif
 248 #endif
 249
 250 /* Maximum allocatable size */
 251 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
 252 /* Maximum size for which we actually use a slab cache */
 253 #define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
 254 /* Maximum order allocatable via the slab allocagtor */
 255 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
 256
 257 /*
 258  * Kmalloc subsystem.
 259  */
 260 #ifndef KMALLOC_MIN_SIZE
 261 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
 262 #endif
 263
 264 /*
 265  * This restriction comes from byte sized index implementation.
 266  * Page size is normally 2^12 bytes and, in this case, if we want to use
 267  * byte sized index which can represent 2^8 entries, the size of the object
 268  * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
 269  * If minimum size of kmalloc is less than 16, we use it as minimum object
 270  * size and give up to use byte sized index.
 271  */
 272 #define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
 273                                (KMALLOC_MIN_SIZE) : 16)
 274
 275 #ifndef CONFIG_SLOB
 276 extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
 277 #ifdef CONFIG_ZONE_DMA
 278 extern struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
 279 #endif
 280
 281 /*
 282  * Figure out which kmalloc slab an allocation of a certain size
 283  * belongs to.
 284  * 0 = zero alloc
 285  * 1 =  65 .. 96 bytes
 286  * 2 = 129 .. 192 bytes
 287  * n = 2^(n-1)+1 .. 2^n
 288  */
 289 static __always_inline int kmalloc_index(size_t size)
 290 {
 291         if (!size)
 292                 return 0;
 293
 294         if (size <= KMALLOC_MIN_SIZE)
 295                 return KMALLOC_SHIFT_LOW;
 296
 297         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 298                 return 1;
 299         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 300                 return 2;
 301         if (size <=          8) return 3;
 302         if (size <=         16) return 4;
 303         if (size <=         32) return 5;
 304         if (size <=         64) return 6;
 305         if (size <=        128) return 7;
 306         if (size <=        256) return 8;
 307         if (size <=        512) return 9;
 308         if (size <=       1024) return 10;
 309         if (size <=   2 * 1024) return 11;
 310         if (size <=   4 * 1024) return 12;
 311         if (size <=   8 * 1024) return 13;
 312         if (size <=  16 * 1024) return 14;
 313         if (size <=  32 * 1024) return 15;
 314         if (size <=  64 * 1024) return 16;
 315         if (size <= 128 * 1024) return 17;
 316         if (size <= 256 * 1024) return 18;
 317         if (size <= 512 * 1024) return 19;
 318         if (size <= 1024 * 1024) return 20;
 319         if (size <=  2 * 1024 * 1024) return 21;
 320         if (size <=  4 * 1024 * 1024) return 22;
 321         if (size <=  8 * 1024 * 1024) return 23;
 322         if (size <=  16 * 1024 * 1024) return 24;
 323         if (size <=  32 * 1024 * 1024) return 25;
 324         if (size <=  64 * 1024 * 1024) return 26;
 325         BUG();
 326
 327         /* Will never be reached. Needed because the compiler may complain */
 328         return -1;
 329 }
 330 #endif /* !CONFIG_SLOB */
 331
 332 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
 333 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
 334 void kmem_cache_free(struct kmem_cache *, void *);
 335
 336 /*
 337  * Bulk allocation and freeing operations. These are accelerated in an
 338  * allocator specific way to avoid taking locks repeatedly or building
 339  * metadata structures unnecessarily.
 340  *
 341  * Note that interrupts must be enabled when calling these functions.
 342  */
 343 void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 344 int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 345
 346 /*
 347  * Caller must not use kfree_bulk() on memory not originally allocated
 348  * by kmalloc(), because the SLOB allocator cannot handle this.
 349  */
 350 static __always_inline void kfree_bulk(size_t size, void **p)
 351 {
 352         kmem_cache_free_bulk(NULL, size, p);
 353 }
 354
 355 #ifdef CONFIG_NUMA
 356 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
 357 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
 358 #else
 359 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 360 {
 361         return __kmalloc(size, flags);
 362 }
 363
 364 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
 365 {
 366         return kmem_cache_alloc(s, flags);
 367 }
 368 #endif
 369
 370 #ifdef CONFIG_TRACING
 371 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
 372
 373 #ifdef CONFIG_NUMA
 374 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 375                                            gfp_t gfpflags,
 376                                            int node, size_t size) __assume_slab_alignment __malloc;
 377 #else
 378 static __always_inline void *
 379 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 380                               gfp_t gfpflags,
 381                               int node, size_t size)
 382 {
 383         return kmem_cache_alloc_trace(s, gfpflags, size);
 384 }
 385 #endif /* CONFIG_NUMA */
 386
 387 #else /* CONFIG_TRACING */
 388 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
 389                 gfp_t flags, size_t size)
 390 {
 391         void *ret = kmem_cache_alloc(s, flags);
 392
 393         kasan_kmalloc(s, ret, size, flags);
 394         return ret;
 395 }
 396
 397 static __always_inline void *
 398 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 399                               gfp_t gfpflags,
 400                               int node, size_t size)
 401 {
 402         void *ret = kmem_cache_alloc_node(s, gfpflags, node);
 403
 404         kasan_kmalloc(s, ret, size, gfpflags);
 405         return ret;
 406 }
 407 #endif /* CONFIG_TRACING */
 408
 409 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
 410
 411 #ifdef CONFIG_TRACING
 412 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
 413 #else
 414 static __always_inline void *
 415 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 416 {
 417         return kmalloc_order(size, flags, order);
 418 }
 419 #endif
 420
 421 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 422 {
 423         unsigned int order = get_order(size);
 424         return kmalloc_order_trace(size, flags, order);
 425 }
 426
 427 /**
 428  * kmalloc - allocate memory
 429  * @size: how many bytes of memory are required.
 430  * @flags: the type of memory to allocate.
 431  *
 432  * kmalloc is the normal method of allocating memory
 433  * for objects smaller than page size in the kernel.
 434  *
 435  * The @flags argument may be one of:
 436  *
 437  * %GFP_USER - Allocate memory on behalf of user.  May sleep.
 438  *
 439  * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
 440  *
 441  * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
 442  *   For example, use this inside interrupt handlers.
 443  *
 444  * %GFP_HIGHUSER - Allocate pages from high memory.
 445  *
 446  * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
 447  *
 448  * %GFP_NOFS - Do not make any fs calls while trying to get memory.
 449  *
 450  * %GFP_NOWAIT - Allocation will not sleep.
 451  *
 452  * %__GFP_THISNODE - Allocate node-local memory only.
 453  *
 454  * %GFP_DMA - Allocation suitable for DMA.
 455  *   Should only be used for kmalloc() caches. Otherwise, use a
 456  *   slab created with SLAB_DMA.
 457  *
 458  * Also it is possible to set different flags by OR'ing
 459  * in one or more of the following additional @flags:
 460  *
 461  * %__GFP_COLD - Request cache-cold pages instead of
 462  *   trying to return cache-warm pages.
 463  *
 464  * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
 465  *
 466  * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
 467  *   (think twice before using).
 468  *
 469  * %__GFP_NORETRY - If memory is not immediately available,
 470  *   then give up at once.
 471  *
 472  * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
 473  *
 474  * %__GFP_RETRY_MAYFAIL - Try really hard to succeed the allocation but fail
 475  *   eventually.
 476  *
 477  * There are other flags available as well, but these are not intended
 478  * for general use, and so are not documented here. For a full list of
 479  * potential flags, always refer to linux/gfp.h.
 480  */
 481 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 482 {
 483         if (__builtin_constant_p(size)) {
 484                 if (size > KMALLOC_MAX_CACHE_SIZE)
 485                         return kmalloc_large(size, flags);
 486 #ifndef CONFIG_SLOB
 487                 if (!(flags & GFP_DMA)) {
 488                         int index = kmalloc_index(size);
 489
 490                         if (!index)
 491                                 return ZERO_SIZE_PTR;
 492
 493                         return kmem_cache_alloc_trace(kmalloc_caches[index],
 494                                         flags, size);
 495                 }
 496 #endif
 497         }
 498         return __kmalloc(size, flags);
 499 }
 500
 501 /*
 502  * Determine size used for the nth kmalloc cache.
 503  * return size or 0 if a kmalloc cache for that
 504  * size does not exist
 505  */
 506 static __always_inline int kmalloc_size(int n)
 507 {
 508 #ifndef CONFIG_SLOB
 509         if (n > 2)
 510                 return 1 << n;
 511
 512         if (n == 1 && KMALLOC_MIN_SIZE <= 32)
 513                 return 96;
 514
 515         if (n == 2 && KMALLOC_MIN_SIZE <= 64)
 516                 return 192;
 517 #endif
 518         return 0;
 519 }
 520
 521 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 522 {
 523 #ifndef CONFIG_SLOB
 524         if (__builtin_constant_p(size) &&
 525                 size <= KMALLOC_MAX_CACHE_SIZE && !(flags & GFP_DMA)) {
 526                 int i = kmalloc_index(size);
 527
 528                 if (!i)
 529                         return ZERO_SIZE_PTR;
 530
 531                 return kmem_cache_alloc_node_trace(kmalloc_caches[i],
 532                                                 flags, node, size);
 533         }
 534 #endif
 535         return __kmalloc_node(size, flags, node);
 536 }
 537
 538 struct memcg_cache_array {
 539         struct rcu_head rcu;
 540         struct kmem_cache *entries[0];
 541 };
 542
 543 /*
 544  * This is the main placeholder for memcg-related information in kmem caches.
 545  * Both the root cache and the child caches will have it. For the root cache,
 546  * this will hold a dynamically allocated array large enough to hold
 547  * information about the currently limited memcgs in the system. To allow the
 548  * array to be accessed without taking any locks, on relocation we free the old
 549  * version only after a grace period.
 550  *
 551  * Root and child caches hold different metadata.
 552  *
 553  * @root_cache: Common to root and child caches.  NULL for root, pointer to
 554  *              the root cache for children.
 555  *
 556  * The following fields are specific to root caches.
 557  *
 558  * @memcg_caches: kmemcg ID indexed table of child caches.  This table is
 559  *              used to index child cachces during allocation and cleared
 560  *              early during shutdown.
 561  *
 562  * @root_caches_node: List node for slab_root_caches list.
 563  *
 564  * @children:   List of all child caches.  While the child caches are also
 565  *              reachable through @memcg_caches, a child cache remains on
 566  *              this list until it is actually destroyed.
 567  *
 568  * The following fields are specific to child caches.
 569  *
 570  * @memcg:      Pointer to the memcg this cache belongs to.
 571  *
 572  * @children_node: List node for @root_cache->children list.
 573  *
 574  * @kmem_caches_node: List node for @memcg->kmem_caches list.
 575  */
 576 struct memcg_cache_params {
 577         struct kmem_cache *root_cache;
 578         union {
 579                 struct {
 580                         struct memcg_cache_array __rcu *memcg_caches;
 581                         struct list_head __root_caches_node;
 582                         struct list_head children;
 583                 };
 584                 struct {
 585                         struct mem_cgroup *memcg;
 586                         struct list_head children_node;
 587                         struct list_head kmem_caches_node;
 588
 589                         void (*deact_fn)(struct kmem_cache *);
 590                         union {
 591                                 struct rcu_head deact_rcu_head;
 592                                 struct work_struct deact_work;
 593                         };
 594                 };
 595         };
 596 };
 597
 598 int memcg_update_all_caches(int num_memcgs);
 599
 600 /**
 601  * kmalloc_array - allocate memory for an array.
 602  * @n: number of elements.
 603  * @size: element size.
 604  * @flags: the type of memory to allocate (see kmalloc).
 605  */
 606 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
 607 {
 608         if (size != 0 && n > SIZE_MAX / size)
 609                 return NULL;
 610         if (__builtin_constant_p(n) && __builtin_constant_p(size))
 611                 return kmalloc(n * size, flags);
 612         return __kmalloc(n * size, flags);
 613 }
 614
 615 /**
 616  * kcalloc - allocate memory for an array. The memory is set to zero.
 617  * @n: number of elements.
 618  * @size: element size.
 619  * @flags: the type of memory to allocate (see kmalloc).
 620  */
 621 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 622 {
 623         return kmalloc_array(n, size, flags | __GFP_ZERO);
 624 }
 625
 626 /*
 627  * kmalloc_track_caller is a special version of kmalloc that records the
 628  * calling function of the routine calling it for slab leak tracking instead
 629  * of just the calling function (confusing, eh?).
 630  * It's useful when the call to kmalloc comes from a widely-used standard
 631  * allocator where we care about the real place the memory allocation
 632  * request comes from.
 633  */
 634 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
 635 #define kmalloc_track_caller(size, flags) \
 636         __kmalloc_track_caller(size, flags, _RET_IP_)
 637
 638 #ifdef CONFIG_NUMA
 639 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
 640 #define kmalloc_node_track_caller(size, flags, node) \
 641         __kmalloc_node_track_caller(size, flags, node, \
 642                         _RET_IP_)
 643
 644 #else /* CONFIG_NUMA */
 645
 646 #define kmalloc_node_track_caller(size, flags, node) \
 647         kmalloc_track_caller(size, flags)
 648
 649 #endif /* CONFIG_NUMA */
 650
 651 /*
 652  * Shortcuts
 653  */
 654 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
 655 {
 656         return kmem_cache_alloc(k, flags | __GFP_ZERO);
 657 }
 658
 659 /**
 660  * kzalloc - allocate memory. The memory is set to zero.
 661  * @size: how many bytes of memory are required.
 662  * @flags: the type of memory to allocate (see kmalloc).
 663  */
 664 static inline void *kzalloc(size_t size, gfp_t flags)
 665 {
 666         return kmalloc(size, flags | __GFP_ZERO);
 667 }
 668
 669 /**
 670  * kzalloc_node - allocate zeroed memory from a particular memory node.
 671  * @size: how many bytes of memory are required.
 672  * @flags: the type of memory to allocate (see kmalloc).
 673  * @node: memory node from which to allocate
 674  */
 675 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
 676 {
 677         return kmalloc_node(size, flags | __GFP_ZERO, node);
 678 }
 679
 680 unsigned int kmem_cache_size(struct kmem_cache *s);
 681 void __init kmem_cache_init_late(void);
 682
 683 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
 684 int slab_prepare_cpu(unsigned int cpu);
 685 int slab_dead_cpu(unsigned int cpu);
 686 #else
 687 #define slab_prepare_cpu        NULL
 688 #define slab_dead_cpu           NULL
 689 #endif
 690
 691 #endif  /* _LINUX_SLAB_H */