linux/include/linux/slab.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
   4 *
   5 * (C) SGI 2006, Christoph Lameter
   6 *      Cleaned up and restructured to ease the addition of alternative
   7 *      implementations of SLAB allocators.
   8 * (C) Linux Foundation 2008-2013
   9 *      Unified interface for all slab allocators
  10 */
  11
  12#ifndef _LINUX_SLAB_H
  13#define _LINUX_SLAB_H
  14
  15#include <linux/gfp.h>
  16#include <linux/overflow.h>
  17#include <linux/types.h>
  18#include <linux/workqueue.h>
  19
  20
  21/*
  22 * Flags to pass to kmem_cache_create().
  23 * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
  24 */
  25/* DEBUG: Perform (expensive) checks on alloc/free */
  26#define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
  27/* DEBUG: Red zone objs in a cache */
  28#define SLAB_RED_ZONE           ((slab_flags_t __force)0x00000400U)
  29/* DEBUG: Poison objects */
  30#define SLAB_POISON             ((slab_flags_t __force)0x00000800U)
  31/* Align objs on cache lines */
  32#define SLAB_HWCACHE_ALIGN      ((slab_flags_t __force)0x00002000U)
  33/* Use GFP_DMA memory */
  34#define SLAB_CACHE_DMA          ((slab_flags_t __force)0x00004000U)
  35/* DEBUG: Store the last owner for bug hunting */
  36#define SLAB_STORE_USER         ((slab_flags_t __force)0x00010000U)
  37/* Panic if kmem_cache_create() fails */
  38#define SLAB_PANIC              ((slab_flags_t __force)0x00040000U)
  39/*
  40 * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
  41 *
  42 * This delays freeing the SLAB page by a grace period, it does _NOT_
  43 * delay object freeing. This means that if you do kmem_cache_free()
  44 * that memory location is free to be reused at any time. Thus it may
  45 * be possible to see another object there in the same RCU grace period.
  46 *
  47 * This feature only ensures the memory location backing the object
  48 * stays valid, the trick to using this is relying on an independent
  49 * object validation pass. Something like:
  50 *
  51 *  rcu_read_lock()
  52 * again:
  53 *  obj = lockless_lookup(key);
  54 *  if (obj) {
  55 *    if (!try_get_ref(obj)) // might fail for free objects
  56 *      goto again;
  57 *
  58 *    if (obj->key != key) { // not the object we expected
  59 *      put_ref(obj);
  60 *      goto again;
  61 *    }
  62 *  }
  63 *  rcu_read_unlock();
  64 *
  65 * This is useful if we need to approach a kernel structure obliquely,
  66 * from its address obtained without the usual locking. We can lock
  67 * the structure to stabilize it and check it's still at the given address,
  68 * only if we can be sure that the memory has not been meanwhile reused
  69 * for some other kind of object (which our subsystem's lock might corrupt).
  70 *
  71 * rcu_read_lock before reading the address, then rcu_read_unlock after
  72 * taking the spinlock within the structure expected at that address.
  73 *
  74 * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
  75 */
  76/* Defer freeing slabs to RCU */
  77#define SLAB_TYPESAFE_BY_RCU    ((slab_flags_t __force)0x00080000U)
  78/* Spread some memory over cpuset */
  79#define SLAB_MEM_SPREAD         ((slab_flags_t __force)0x00100000U)
  80/* Trace allocations and frees */
  81#define SLAB_TRACE              ((slab_flags_t __force)0x00200000U)
  82
  83/* Flag to prevent checks on free */
  84#ifdef CONFIG_DEBUG_OBJECTS
  85# define SLAB_DEBUG_OBJECTS     ((slab_flags_t __force)0x00400000U)
  86#else
  87# define SLAB_DEBUG_OBJECTS     0
  88#endif
  89
  90/* Avoid kmemleak tracing */
  91#define SLAB_NOLEAKTRACE        ((slab_flags_t __force)0x00800000U)
  92
  93/* Fault injection mark */
  94#ifdef CONFIG_FAILSLAB
  95# define SLAB_FAILSLAB          ((slab_flags_t __force)0x02000000U)
  96#else
  97# define SLAB_FAILSLAB          0
  98#endif
  99/* Account to memcg */
 100#ifdef CONFIG_MEMCG_KMEM
 101# define SLAB_ACCOUNT           ((slab_flags_t __force)0x04000000U)
 102#else
 103# define SLAB_ACCOUNT           0
 104#endif
 105
 106#ifdef CONFIG_KASAN
 107#define SLAB_KASAN              ((slab_flags_t __force)0x08000000U)
 108#else
 109#define SLAB_KASAN              0
 110#endif
 111
 112/* The following flags affect the page allocator grouping pages by mobility */
 113/* Objects are reclaimable */
 114#define SLAB_RECLAIM_ACCOUNT    ((slab_flags_t __force)0x00020000U)
 115#define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
 116/*
 117 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
 118 *
 119 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
 120 *
 121 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
 122 * Both make kfree a no-op.
 123 */
 124#define ZERO_SIZE_PTR ((void *)16)
 125
 126#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
 127                                (unsigned long)ZERO_SIZE_PTR)
 128
 129#include <linux/kasan.h>
 130
 131struct mem_cgroup;
 132/*
 133 * struct kmem_cache related prototypes
 134 */
 135void __init kmem_cache_init(void);
 136bool slab_is_available(void);
 137
 138extern bool usercopy_fallback;
 139
 140struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
 141                        unsigned int align, slab_flags_t flags,
 142                        void (*ctor)(void *));
 143struct kmem_cache *kmem_cache_create_usercopy(const char *name,
 144                        unsigned int size, unsigned int align,
 145                        slab_flags_t flags,
 146                        unsigned int useroffset, unsigned int usersize,
 147                        void (*ctor)(void *));
 148void kmem_cache_destroy(struct kmem_cache *);
 149int kmem_cache_shrink(struct kmem_cache *);
 150
 151void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *);
 152void memcg_deactivate_kmem_caches(struct mem_cgroup *);
 153void memcg_destroy_kmem_caches(struct mem_cgroup *);
 154
 155/*
 156 * Please use this macro to create slab caches. Simply specify the
 157 * name of the structure and maybe some flags that are listed above.
 158 *
 159 * The alignment of the struct determines object alignment. If you
 160 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
 161 * then the objects will be properly aligned in SMP configurations.
 162 */
 163#define KMEM_CACHE(__struct, __flags)                                   \
 164                kmem_cache_create(#__struct, sizeof(struct __struct),   \
 165                        __alignof__(struct __struct), (__flags), NULL)
 166
 167/*
 168 * To whitelist a single field for copying to/from usercopy, use this
 169 * macro instead for KMEM_CACHE() above.
 170 */
 171#define KMEM_CACHE_USERCOPY(__struct, __flags, __field)                 \
 172                kmem_cache_create_usercopy(#__struct,                   \
 173                        sizeof(struct __struct),                        \
 174                        __alignof__(struct __struct), (__flags),        \
 175                        offsetof(struct __struct, __field),             \
 176                        sizeof_field(struct __struct, __field), NULL)
 177
 178/*
 179 * Common kmalloc functions provided by all allocators
 180 */
 181void * __must_check __krealloc(const void *, size_t, gfp_t);
 182void * __must_check krealloc(const void *, size_t, gfp_t);
 183void kfree(const void *);
 184void kzfree(const void *);
 185size_t ksize(const void *);
 186
 187#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
 188void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
 189                        bool to_user);
 190#else
 191static inline void __check_heap_object(const void *ptr, unsigned long n,
 192                                       struct page *page, bool to_user) { }
 193#endif
 194
 195/*
 196 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
 197 * alignment larger than the alignment of a 64-bit integer.
 198 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
 199 */
 200#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 201#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
 202#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 203#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
 204#else
 205#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
 206#endif
 207
 208/*
 209 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
 210 * Intended for arches that get misalignment faults even for 64 bit integer
 211 * aligned buffers.
 212 */
 213#ifndef ARCH_SLAB_MINALIGN
 214#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 215#endif
 216
 217/*
 218 * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
 219 * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
 220 * aligned pointers.
 221 */
 222#define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
 223#define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
 224#define __assume_page_alignment __assume_aligned(PAGE_SIZE)
 225
 226/*
 227 * Kmalloc array related definitions
 228 */
 229
 230#ifdef CONFIG_SLAB
 231/*
 232 * The largest kmalloc size supported by the SLAB allocators is
 233 * 32 megabyte (2^25) or the maximum allocatable page order if that is
 234 * less than 32 MB.
 235 *
 236 * WARNING: Its not easy to increase this value since the allocators have
 237 * to do various tricks to work around compiler limitations in order to
 238 * ensure proper constant folding.
 239 */
 240#define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
 241                                (MAX_ORDER + PAGE_SHIFT - 1) : 25)
 242#define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
 243#ifndef KMALLOC_SHIFT_LOW
 244#define KMALLOC_SHIFT_LOW       5
 245#endif
 246#endif
 247
 248#ifdef CONFIG_SLUB
 249/*
 250 * SLUB directly allocates requests fitting in to an order-1 page
 251 * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
 252 */
 253#define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
 254#define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
 255#ifndef KMALLOC_SHIFT_LOW
 256#define KMALLOC_SHIFT_LOW       3
 257#endif
 258#endif
 259
 260#ifdef CONFIG_SLOB
 261/*
 262 * SLOB passes all requests larger than one page to the page allocator.
 263 * No kmalloc array is necessary since objects of different sizes can
 264 * be allocated from the same page.
 265 */
 266#define KMALLOC_SHIFT_HIGH      PAGE_SHIFT
 267#define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
 268#ifndef KMALLOC_SHIFT_LOW
 269#define KMALLOC_SHIFT_LOW       3
 270#endif
 271#endif
 272
 273/* Maximum allocatable size */
 274#define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
 275/* Maximum size for which we actually use a slab cache */
 276#define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
 277/* Maximum order allocatable via the slab allocagtor */
 278#define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
 279
 280/*
 281 * Kmalloc subsystem.
 282 */
 283#ifndef KMALLOC_MIN_SIZE
 284#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
 285#endif
 286
 287/*
 288 * This restriction comes from byte sized index implementation.
 289 * Page size is normally 2^12 bytes and, in this case, if we want to use
 290 * byte sized index which can represent 2^8 entries, the size of the object
 291 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
 292 * If minimum size of kmalloc is less than 16, we use it as minimum object
 293 * size and give up to use byte sized index.
 294 */
 295#define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
 296                               (KMALLOC_MIN_SIZE) : 16)
 297
 298#ifndef CONFIG_SLOB
 299extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
 300#ifdef CONFIG_ZONE_DMA
 301extern struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
 302#endif
 303
 304/*
 305 * Figure out which kmalloc slab an allocation of a certain size
 306 * belongs to.
 307 * 0 = zero alloc
 308 * 1 =  65 .. 96 bytes
 309 * 2 = 129 .. 192 bytes
 310 * n = 2^(n-1)+1 .. 2^n
 311 */
 312static __always_inline unsigned int kmalloc_index(size_t size)
 313{
 314        if (!size)
 315                return 0;
 316
 317        if (size <= KMALLOC_MIN_SIZE)
 318                return KMALLOC_SHIFT_LOW;
 319
 320        if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 321                return 1;
 322        if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 323                return 2;
 324        if (size <=          8) return 3;
 325        if (size <=         16) return 4;
 326        if (size <=         32) return 5;
 327        if (size <=         64) return 6;
 328        if (size <=        128) return 7;
 329        if (size <=        256) return 8;
 330        if (size <=        512) return 9;
 331        if (size <=       1024) return 10;
 332        if (size <=   2 * 1024) return 11;
 333        if (size <=   4 * 1024) return 12;
 334        if (size <=   8 * 1024) return 13;
 335        if (size <=  16 * 1024) return 14;
 336        if (size <=  32 * 1024) return 15;
 337        if (size <=  64 * 1024) return 16;
 338        if (size <= 128 * 1024) return 17;
 339        if (size <= 256 * 1024) return 18;
 340        if (size <= 512 * 1024) return 19;
 341        if (size <= 1024 * 1024) return 20;
 342        if (size <=  2 * 1024 * 1024) return 21;
 343        if (size <=  4 * 1024 * 1024) return 22;
 344        if (size <=  8 * 1024 * 1024) return 23;
 345        if (size <=  16 * 1024 * 1024) return 24;
 346        if (size <=  32 * 1024 * 1024) return 25;
 347        if (size <=  64 * 1024 * 1024) return 26;
 348        BUG();
 349
 350        /* Will never be reached. Needed because the compiler may complain */
 351        return -1;
 352}
 353#endif /* !CONFIG_SLOB */
 354
 355void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
 356void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
 357void kmem_cache_free(struct kmem_cache *, void *);
 358
 359/*
 360 * Bulk allocation and freeing operations. These are accelerated in an
 361 * allocator specific way to avoid taking locks repeatedly or building
 362 * metadata structures unnecessarily.
 363 *
 364 * Note that interrupts must be enabled when calling these functions.
 365 */
 366void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 367int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 368
 369/*
 370 * Caller must not use kfree_bulk() on memory not originally allocated
 371 * by kmalloc(), because the SLOB allocator cannot handle this.
 372 */
 373static __always_inline void kfree_bulk(size_t size, void **p)
 374{
 375        kmem_cache_free_bulk(NULL, size, p);
 376}
 377
 378#ifdef CONFIG_NUMA
 379void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
 380void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
 381#else
 382static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 383{
 384        return __kmalloc(size, flags);
 385}
 386
 387static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
 388{
 389        return kmem_cache_alloc(s, flags);
 390}
 391#endif
 392
 393#ifdef CONFIG_TRACING
 394extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
 395
 396#ifdef CONFIG_NUMA
 397extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 398                                           gfp_t gfpflags,
 399                                           int node, size_t size) __assume_slab_alignment __malloc;
 400#else
 401static __always_inline void *
 402kmem_cache_alloc_node_trace(struct kmem_cache *s,
 403                              gfp_t gfpflags,
 404                              int node, size_t size)
 405{
 406        return kmem_cache_alloc_trace(s, gfpflags, size);
 407}
 408#endif /* CONFIG_NUMA */
 409
 410#else /* CONFIG_TRACING */
 411static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
 412                gfp_t flags, size_t size)
 413{
 414        void *ret = kmem_cache_alloc(s, flags);
 415
 416        kasan_kmalloc(s, ret, size, flags);
 417        return ret;
 418}
 419
 420static __always_inline void *
 421kmem_cache_alloc_node_trace(struct kmem_cache *s,
 422                              gfp_t gfpflags,
 423                              int node, size_t size)
 424{
 425        void *ret = kmem_cache_alloc_node(s, gfpflags, node);
 426
 427        kasan_kmalloc(s, ret, size, gfpflags);
 428        return ret;
 429}
 430#endif /* CONFIG_TRACING */
 431
 432extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
 433
 434#ifdef CONFIG_TRACING
 435extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
 436#else
 437static __always_inline void *
 438kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 439{
 440        return kmalloc_order(size, flags, order);
 441}
 442#endif
 443
 444static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 445{
 446        unsigned int order = get_order(size);
 447        return kmalloc_order_trace(size, flags, order);
 448}
 449
 450/**
 451 * kmalloc - allocate memory
 452 * @size: how many bytes of memory are required.
 453 * @flags: the type of memory to allocate.
 454 *
 455 * kmalloc is the normal method of allocating memory
 456 * for objects smaller than page size in the kernel.
 457 *
 458 * The @flags argument may be one of:
 459 *
 460 * %GFP_USER - Allocate memory on behalf of user.  May sleep.
 461 *
 462 * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
 463 *
 464 * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
 465 *   For example, use this inside interrupt handlers.
 466 *
 467 * %GFP_HIGHUSER - Allocate pages from high memory.
 468 *
 469 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
 470 *
 471 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
 472 *
 473 * %GFP_NOWAIT - Allocation will not sleep.
 474 *
 475 * %__GFP_THISNODE - Allocate node-local memory only.
 476 *
 477 * %GFP_DMA - Allocation suitable for DMA.
 478 *   Should only be used for kmalloc() caches. Otherwise, use a
 479 *   slab created with SLAB_DMA.
 480 *
 481 * Also it is possible to set different flags by OR'ing
 482 * in one or more of the following additional @flags:
 483 *
 484 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
 485 *
 486 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
 487 *   (think twice before using).
 488 *
 489 * %__GFP_NORETRY - If memory is not immediately available,
 490 *   then give up at once.
 491 *
 492 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
 493 *
 494 * %__GFP_RETRY_MAYFAIL - Try really hard to succeed the allocation but fail
 495 *   eventually.
 496 *
 497 * There are other flags available as well, but these are not intended
 498 * for general use, and so are not documented here. For a full list of
 499 * potential flags, always refer to linux/gfp.h.
 500 */
 501static __always_inline void *kmalloc(size_t size, gfp_t flags)
 502{
 503        if (__builtin_constant_p(size)) {
 504                if (size > KMALLOC_MAX_CACHE_SIZE)
 505                        return kmalloc_large(size, flags);
 506#ifndef CONFIG_SLOB
 507                if (!(flags & GFP_DMA)) {
 508                        unsigned int index = kmalloc_index(size);
 509
 510                        if (!index)
 511                                return ZERO_SIZE_PTR;
 512
 513                        return kmem_cache_alloc_trace(kmalloc_caches[index],
 514                                        flags, size);
 515                }
 516#endif
 517        }
 518        return __kmalloc(size, flags);
 519}
 520
 521/*
 522 * Determine size used for the nth kmalloc cache.
 523 * return size or 0 if a kmalloc cache for that
 524 * size does not exist
 525 */
 526static __always_inline unsigned int kmalloc_size(unsigned int n)
 527{
 528#ifndef CONFIG_SLOB
 529        if (n > 2)
 530                return 1U << n;
 531
 532        if (n == 1 && KMALLOC_MIN_SIZE <= 32)
 533                return 96;
 534
 535        if (n == 2 && KMALLOC_MIN_SIZE <= 64)
 536                return 192;
 537#endif
 538        return 0;
 539}
 540
 541static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 542{
 543#ifndef CONFIG_SLOB
 544        if (__builtin_constant_p(size) &&
 545                size <= KMALLOC_MAX_CACHE_SIZE && !(flags & GFP_DMA)) {
 546                unsigned int i = kmalloc_index(size);
 547
 548                if (!i)
 549                        return ZERO_SIZE_PTR;
 550
 551                return kmem_cache_alloc_node_trace(kmalloc_caches[i],
 552                                                flags, node, size);
 553        }
 554#endif
 555        return __kmalloc_node(size, flags, node);
 556}
 557
 558struct memcg_cache_array {
 559        struct rcu_head rcu;
 560        struct kmem_cache *entries[0];
 561};
 562
 563/*
 564 * This is the main placeholder for memcg-related information in kmem caches.
 565 * Both the root cache and the child caches will have it. For the root cache,
 566 * this will hold a dynamically allocated array large enough to hold
 567 * information about the currently limited memcgs in the system. To allow the
 568 * array to be accessed without taking any locks, on relocation we free the old
 569 * version only after a grace period.
 570 *
 571 * Root and child caches hold different metadata.
 572 *
 573 * @root_cache: Common to root and child caches.  NULL for root, pointer to
 574 *              the root cache for children.
 575 *
 576 * The following fields are specific to root caches.
 577 *
 578 * @memcg_caches: kmemcg ID indexed table of child caches.  This table is
 579 *              used to index child cachces during allocation and cleared
 580 *              early during shutdown.
 581 *
 582 * @root_caches_node: List node for slab_root_caches list.
 583 *
 584 * @children:   List of all child caches.  While the child caches are also
 585 *              reachable through @memcg_caches, a child cache remains on
 586 *              this list until it is actually destroyed.
 587 *
 588 * The following fields are specific to child caches.
 589 *
 590 * @memcg:      Pointer to the memcg this cache belongs to.
 591 *
 592 * @children_node: List node for @root_cache->children list.
 593 *
 594 * @kmem_caches_node: List node for @memcg->kmem_caches list.
 595 */
 596struct memcg_cache_params {
 597        struct kmem_cache *root_cache;
 598        union {
 599                struct {
 600                        struct memcg_cache_array __rcu *memcg_caches;
 601                        struct list_head __root_caches_node;
 602                        struct list_head children;
 603                        bool dying;
 604                };
 605                struct {
 606                        struct mem_cgroup *memcg;
 607                        struct list_head children_node;
 608                        struct list_head kmem_caches_node;
 609
 610                        void (*deact_fn)(struct kmem_cache *);
 611                        union {
 612                                struct rcu_head deact_rcu_head;
 613                                struct work_struct deact_work;
 614                        };
 615                };
 616        };
 617};
 618
 619int memcg_update_all_caches(int num_memcgs);
 620
 621/**
 622 * kmalloc_array - allocate memory for an array.
 623 * @n: number of elements.
 624 * @size: element size.
 625 * @flags: the type of memory to allocate (see kmalloc).
 626 */
 627static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
 628{
 629        size_t bytes;
 630
 631        if (unlikely(check_mul_overflow(n, size, &bytes)))
 632                return NULL;
 633        if (__builtin_constant_p(n) && __builtin_constant_p(size))
 634                return kmalloc(bytes, flags);
 635        return __kmalloc(bytes, flags);
 636}
 637
 638/**
 639 * kcalloc - allocate memory for an array. The memory is set to zero.
 640 * @n: number of elements.
 641 * @size: element size.
 642 * @flags: the type of memory to allocate (see kmalloc).
 643 */
 644static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 645{
 646        return kmalloc_array(n, size, flags | __GFP_ZERO);
 647}
 648
 649/*
 650 * kmalloc_track_caller is a special version of kmalloc that records the
 651 * calling function of the routine calling it for slab leak tracking instead
 652 * of just the calling function (confusing, eh?).
 653 * It's useful when the call to kmalloc comes from a widely-used standard
 654 * allocator where we care about the real place the memory allocation
 655 * request comes from.
 656 */
 657extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
 658#define kmalloc_track_caller(size, flags) \
 659        __kmalloc_track_caller(size, flags, _RET_IP_)
 660
 661static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
 662                                       int node)
 663{
 664        size_t bytes;
 665
 666        if (unlikely(check_mul_overflow(n, size, &bytes)))
 667                return NULL;
 668        if (__builtin_constant_p(n) && __builtin_constant_p(size))
 669                return kmalloc_node(bytes, flags, node);
 670        return __kmalloc_node(bytes, flags, node);
 671}
 672
 673static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
 674{
 675        return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
 676}
 677
 678
 679#ifdef CONFIG_NUMA
 680extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
 681#define kmalloc_node_track_caller(size, flags, node) \
 682        __kmalloc_node_track_caller(size, flags, node, \
 683                        _RET_IP_)
 684
 685#else /* CONFIG_NUMA */
 686
 687#define kmalloc_node_track_caller(size, flags, node) \
 688        kmalloc_track_caller(size, flags)
 689
 690#endif /* CONFIG_NUMA */
 691
 692/*
 693 * Shortcuts
 694 */
 695static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
 696{
 697        return kmem_cache_alloc(k, flags | __GFP_ZERO);
 698}
 699
 700/**
 701 * kzalloc - allocate memory. The memory is set to zero.
 702 * @size: how many bytes of memory are required.
 703 * @flags: the type of memory to allocate (see kmalloc).
 704 */
 705static inline void *kzalloc(size_t size, gfp_t flags)
 706{
 707        return kmalloc(size, flags | __GFP_ZERO);
 708}
 709
 710/**
 711 * kzalloc_node - allocate zeroed memory from a particular memory node.
 712 * @size: how many bytes of memory are required.
 713 * @flags: the type of memory to allocate (see kmalloc).
 714 * @node: memory node from which to allocate
 715 */
 716static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
 717{
 718        return kmalloc_node(size, flags | __GFP_ZERO, node);
 719}
 720
 721unsigned int kmem_cache_size(struct kmem_cache *s);
 722void __init kmem_cache_init_late(void);
 723
 724#if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
 725int slab_prepare_cpu(unsigned int cpu);
 726int slab_dead_cpu(unsigned int cpu);
 727#else
 728#define slab_prepare_cpu        NULL
 729#define slab_dead_cpu           NULL
 730#endif
 731
 732#endif  /* _LINUX_SLAB_H */
 733