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

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