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Linux/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_SLAB_DEBUG is set.
 22  */
 23 #define SLAB_DEBUG_FREE         0x00000100UL    /* DEBUG: Perform (expensive) checks on 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_DESTROY_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 #define SLAB_DESTROY_BY_RCU     0x00080000UL    /* Defer freeing slabs to RCU */
 66 #define SLAB_MEM_SPREAD         0x00100000UL    /* Spread some memory over cpuset */
 67 #define SLAB_TRACE              0x00200000UL    /* Trace allocations and frees */
 68 
 69 /* Flag to prevent checks on free */
 70 #ifdef CONFIG_DEBUG_OBJECTS
 71 # define SLAB_DEBUG_OBJECTS     0x00400000UL
 72 #else
 73 # define SLAB_DEBUG_OBJECTS     0x00000000UL
 74 #endif
 75 
 76 #define SLAB_NOLEAKTRACE        0x00800000UL    /* Avoid kmemleak tracing */
 77 
 78 /* Don't track use of uninitialized memory */
 79 #ifdef CONFIG_KMEMCHECK
 80 # define SLAB_NOTRACK           0x01000000UL
 81 #else
 82 # define SLAB_NOTRACK           0x00000000UL
 83 #endif
 84 #ifdef CONFIG_FAILSLAB
 85 # define SLAB_FAILSLAB          0x02000000UL    /* Fault injection mark */
 86 #else
 87 # define SLAB_FAILSLAB          0x00000000UL
 88 #endif
 89 
 90 /* The following flags affect the page allocator grouping pages by mobility */
 91 #define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
 92 #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
 93 /*
 94  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
 95  *
 96  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
 97  *
 98  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
 99  * Both make kfree a no-op.
100  */
101 #define ZERO_SIZE_PTR ((void *)16)
102 
103 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
104                                 (unsigned long)ZERO_SIZE_PTR)
105 
106 #include <linux/kmemleak.h>
107 
108 struct mem_cgroup;
109 /*
110  * struct kmem_cache related prototypes
111  */
112 void __init kmem_cache_init(void);
113 int slab_is_available(void);
114 
115 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
116                         unsigned long,
117                         void (*)(void *));
118 #ifdef CONFIG_MEMCG_KMEM
119 struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *,
120                                            struct kmem_cache *,
121                                            const char *);
122 #endif
123 void kmem_cache_destroy(struct kmem_cache *);
124 int kmem_cache_shrink(struct kmem_cache *);
125 void kmem_cache_free(struct kmem_cache *, void *);
126 
127 /*
128  * Please use this macro to create slab caches. Simply specify the
129  * name of the structure and maybe some flags that are listed above.
130  *
131  * The alignment of the struct determines object alignment. If you
132  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
133  * then the objects will be properly aligned in SMP configurations.
134  */
135 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
136                 sizeof(struct __struct), __alignof__(struct __struct),\
137                 (__flags), NULL)
138 
139 /*
140  * Common kmalloc functions provided by all allocators
141  */
142 void * __must_check __krealloc(const void *, size_t, gfp_t);
143 void * __must_check krealloc(const void *, size_t, gfp_t);
144 void kfree(const void *);
145 void kzfree(const void *);
146 size_t ksize(const void *);
147 
148 /*
149  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
150  * alignment larger than the alignment of a 64-bit integer.
151  * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
152  */
153 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
154 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
155 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
156 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
157 #else
158 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
159 #endif
160 
161 #ifdef CONFIG_SLOB
162 /*
163  * Common fields provided in kmem_cache by all slab allocators
164  * This struct is either used directly by the allocator (SLOB)
165  * or the allocator must include definitions for all fields
166  * provided in kmem_cache_common in their definition of kmem_cache.
167  *
168  * Once we can do anonymous structs (C11 standard) we could put a
169  * anonymous struct definition in these allocators so that the
170  * separate allocations in the kmem_cache structure of SLAB and
171  * SLUB is no longer needed.
172  */
173 struct kmem_cache {
174         unsigned int object_size;/* The original size of the object */
175         unsigned int size;      /* The aligned/padded/added on size  */
176         unsigned int align;     /* Alignment as calculated */
177         unsigned long flags;    /* Active flags on the slab */
178         const char *name;       /* Slab name for sysfs */
179         int refcount;           /* Use counter */
180         void (*ctor)(void *);   /* Called on object slot creation */
181         struct list_head list;  /* List of all slab caches on the system */
182 };
183 
184 #endif /* CONFIG_SLOB */
185 
186 /*
187  * Kmalloc array related definitions
188  */
189 
190 #ifdef CONFIG_SLAB
191 /*
192  * The largest kmalloc size supported by the SLAB allocators is
193  * 32 megabyte (2^25) or the maximum allocatable page order if that is
194  * less than 32 MB.
195  *
196  * WARNING: Its not easy to increase this value since the allocators have
197  * to do various tricks to work around compiler limitations in order to
198  * ensure proper constant folding.
199  */
200 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
201                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
202 #define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
203 #ifndef KMALLOC_SHIFT_LOW
204 #define KMALLOC_SHIFT_LOW       5
205 #endif
206 #endif
207 
208 #ifdef CONFIG_SLUB
209 /*
210  * SLUB directly allocates requests fitting in to an order-1 page
211  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
212  */
213 #define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
214 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT)
215 #ifndef KMALLOC_SHIFT_LOW
216 #define KMALLOC_SHIFT_LOW       3
217 #endif
218 #endif
219 
220 #ifdef CONFIG_SLOB
221 /*
222  * SLOB passes all requests larger than one page to the page allocator.
223  * No kmalloc array is necessary since objects of different sizes can
224  * be allocated from the same page.
225  */
226 #define KMALLOC_SHIFT_HIGH      PAGE_SHIFT
227 #define KMALLOC_SHIFT_MAX       30
228 #ifndef KMALLOC_SHIFT_LOW
229 #define KMALLOC_SHIFT_LOW       3
230 #endif
231 #endif
232 
233 /* Maximum allocatable size */
234 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
235 /* Maximum size for which we actually use a slab cache */
236 #define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
237 /* Maximum order allocatable via the slab allocagtor */
238 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
239 
240 /*
241  * Kmalloc subsystem.
242  */
243 #ifndef KMALLOC_MIN_SIZE
244 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
245 #endif
246 
247 /*
248  * This restriction comes from byte sized index implementation.
249  * Page size is normally 2^12 bytes and, in this case, if we want to use
250  * byte sized index which can represent 2^8 entries, the size of the object
251  * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
252  * If minimum size of kmalloc is less than 16, we use it as minimum object
253  * size and give up to use byte sized index.
254  */
255 #define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
256                                (KMALLOC_MIN_SIZE) : 16)
257 
258 #ifndef CONFIG_SLOB
259 extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
260 #ifdef CONFIG_ZONE_DMA
261 extern struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
262 #endif
263 
264 /*
265  * Figure out which kmalloc slab an allocation of a certain size
266  * belongs to.
267  * 0 = zero alloc
268  * 1 =  65 .. 96 bytes
269  * 2 = 120 .. 192 bytes
270  * n = 2^(n-1) .. 2^n -1
271  */
272 static __always_inline int kmalloc_index(size_t size)
273 {
274         if (!size)
275                 return 0;
276 
277         if (size <= KMALLOC_MIN_SIZE)
278                 return KMALLOC_SHIFT_LOW;
279 
280         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
281                 return 1;
282         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
283                 return 2;
284         if (size <=          8) return 3;
285         if (size <=         16) return 4;
286         if (size <=         32) return 5;
287         if (size <=         64) return 6;
288         if (size <=        128) return 7;
289         if (size <=        256) return 8;
290         if (size <=        512) return 9;
291         if (size <=       1024) return 10;
292         if (size <=   2 * 1024) return 11;
293         if (size <=   4 * 1024) return 12;
294         if (size <=   8 * 1024) return 13;
295         if (size <=  16 * 1024) return 14;
296         if (size <=  32 * 1024) return 15;
297         if (size <=  64 * 1024) return 16;
298         if (size <= 128 * 1024) return 17;
299         if (size <= 256 * 1024) return 18;
300         if (size <= 512 * 1024) return 19;
301         if (size <= 1024 * 1024) return 20;
302         if (size <=  2 * 1024 * 1024) return 21;
303         if (size <=  4 * 1024 * 1024) return 22;
304         if (size <=  8 * 1024 * 1024) return 23;
305         if (size <=  16 * 1024 * 1024) return 24;
306         if (size <=  32 * 1024 * 1024) return 25;
307         if (size <=  64 * 1024 * 1024) return 26;
308         BUG();
309 
310         /* Will never be reached. Needed because the compiler may complain */
311         return -1;
312 }
313 #endif /* !CONFIG_SLOB */
314 
315 void *__kmalloc(size_t size, gfp_t flags);
316 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags);
317 
318 #ifdef CONFIG_NUMA
319 void *__kmalloc_node(size_t size, gfp_t flags, int node);
320 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
321 #else
322 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
323 {
324         return __kmalloc(size, flags);
325 }
326 
327 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
328 {
329         return kmem_cache_alloc(s, flags);
330 }
331 #endif
332 
333 #ifdef CONFIG_TRACING
334 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t);
335 
336 #ifdef CONFIG_NUMA
337 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
338                                            gfp_t gfpflags,
339                                            int node, size_t size);
340 #else
341 static __always_inline void *
342 kmem_cache_alloc_node_trace(struct kmem_cache *s,
343                               gfp_t gfpflags,
344                               int node, size_t size)
345 {
346         return kmem_cache_alloc_trace(s, gfpflags, size);
347 }
348 #endif /* CONFIG_NUMA */
349 
350 #else /* CONFIG_TRACING */
351 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
352                 gfp_t flags, size_t size)
353 {
354         return kmem_cache_alloc(s, flags);
355 }
356 
357 static __always_inline void *
358 kmem_cache_alloc_node_trace(struct kmem_cache *s,
359                               gfp_t gfpflags,
360                               int node, size_t size)
361 {
362         return kmem_cache_alloc_node(s, gfpflags, node);
363 }
364 #endif /* CONFIG_TRACING */
365 
366 #ifdef CONFIG_SLAB
367 #include <linux/slab_def.h>
368 #endif
369 
370 #ifdef CONFIG_SLUB
371 #include <linux/slub_def.h>
372 #endif
373 
374 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order);
375 
376 #ifdef CONFIG_TRACING
377 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
378 #else
379 static __always_inline void *
380 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
381 {
382         return kmalloc_order(size, flags, order);
383 }
384 #endif
385 
386 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
387 {
388         unsigned int order = get_order(size);
389         return kmalloc_order_trace(size, flags, order);
390 }
391 
392 /**
393  * kmalloc - allocate memory
394  * @size: how many bytes of memory are required.
395  * @flags: the type of memory to allocate.
396  *
397  * kmalloc is the normal method of allocating memory
398  * for objects smaller than page size in the kernel.
399  *
400  * The @flags argument may be one of:
401  *
402  * %GFP_USER - Allocate memory on behalf of user.  May sleep.
403  *
404  * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
405  *
406  * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
407  *   For example, use this inside interrupt handlers.
408  *
409  * %GFP_HIGHUSER - Allocate pages from high memory.
410  *
411  * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
412  *
413  * %GFP_NOFS - Do not make any fs calls while trying to get memory.
414  *
415  * %GFP_NOWAIT - Allocation will not sleep.
416  *
417  * %__GFP_THISNODE - Allocate node-local memory only.
418  *
419  * %GFP_DMA - Allocation suitable for DMA.
420  *   Should only be used for kmalloc() caches. Otherwise, use a
421  *   slab created with SLAB_DMA.
422  *
423  * Also it is possible to set different flags by OR'ing
424  * in one or more of the following additional @flags:
425  *
426  * %__GFP_COLD - Request cache-cold pages instead of
427  *   trying to return cache-warm pages.
428  *
429  * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
430  *
431  * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
432  *   (think twice before using).
433  *
434  * %__GFP_NORETRY - If memory is not immediately available,
435  *   then give up at once.
436  *
437  * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
438  *
439  * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
440  *
441  * There are other flags available as well, but these are not intended
442  * for general use, and so are not documented here. For a full list of
443  * potential flags, always refer to linux/gfp.h.
444  */
445 static __always_inline void *kmalloc(size_t size, gfp_t flags)
446 {
447         if (__builtin_constant_p(size)) {
448                 if (size > KMALLOC_MAX_CACHE_SIZE)
449                         return kmalloc_large(size, flags);
450 #ifndef CONFIG_SLOB
451                 if (!(flags & GFP_DMA)) {
452                         int index = kmalloc_index(size);
453 
454                         if (!index)
455                                 return ZERO_SIZE_PTR;
456 
457                         return kmem_cache_alloc_trace(kmalloc_caches[index],
458                                         flags, size);
459                 }
460 #endif
461         }
462         return __kmalloc(size, flags);
463 }
464 
465 /*
466  * Determine size used for the nth kmalloc cache.
467  * return size or 0 if a kmalloc cache for that
468  * size does not exist
469  */
470 static __always_inline int kmalloc_size(int n)
471 {
472 #ifndef CONFIG_SLOB
473         if (n > 2)
474                 return 1 << n;
475 
476         if (n == 1 && KMALLOC_MIN_SIZE <= 32)
477                 return 96;
478 
479         if (n == 2 && KMALLOC_MIN_SIZE <= 64)
480                 return 192;
481 #endif
482         return 0;
483 }
484 
485 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
486 {
487 #ifndef CONFIG_SLOB
488         if (__builtin_constant_p(size) &&
489                 size <= KMALLOC_MAX_CACHE_SIZE && !(flags & GFP_DMA)) {
490                 int i = kmalloc_index(size);
491 
492                 if (!i)
493                         return ZERO_SIZE_PTR;
494 
495                 return kmem_cache_alloc_node_trace(kmalloc_caches[i],
496                                                 flags, node, size);
497         }
498 #endif
499         return __kmalloc_node(size, flags, node);
500 }
501 
502 /*
503  * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
504  * Intended for arches that get misalignment faults even for 64 bit integer
505  * aligned buffers.
506  */
507 #ifndef ARCH_SLAB_MINALIGN
508 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
509 #endif
510 /*
511  * This is the main placeholder for memcg-related information in kmem caches.
512  * struct kmem_cache will hold a pointer to it, so the memory cost while
513  * disabled is 1 pointer. The runtime cost while enabled, gets bigger than it
514  * would otherwise be if that would be bundled in kmem_cache: we'll need an
515  * extra pointer chase. But the trade off clearly lays in favor of not
516  * penalizing non-users.
517  *
518  * Both the root cache and the child caches will have it. For the root cache,
519  * this will hold a dynamically allocated array large enough to hold
520  * information about the currently limited memcgs in the system. To allow the
521  * array to be accessed without taking any locks, on relocation we free the old
522  * version only after a grace period.
523  *
524  * Child caches will hold extra metadata needed for its operation. Fields are:
525  *
526  * @memcg: pointer to the memcg this cache belongs to
527  * @list: list_head for the list of all caches in this memcg
528  * @root_cache: pointer to the global, root cache, this cache was derived from
529  * @nr_pages: number of pages that belongs to this cache.
530  */
531 struct memcg_cache_params {
532         bool is_root_cache;
533         union {
534                 struct {
535                         struct rcu_head rcu_head;
536                         struct kmem_cache *memcg_caches[0];
537                 };
538                 struct {
539                         struct mem_cgroup *memcg;
540                         struct list_head list;
541                         struct kmem_cache *root_cache;
542                         atomic_t nr_pages;
543                 };
544         };
545 };
546 
547 int memcg_update_all_caches(int num_memcgs);
548 
549 struct seq_file;
550 int cache_show(struct kmem_cache *s, struct seq_file *m);
551 void print_slabinfo_header(struct seq_file *m);
552 
553 /**
554  * kmalloc_array - allocate memory for an array.
555  * @n: number of elements.
556  * @size: element size.
557  * @flags: the type of memory to allocate (see kmalloc).
558  */
559 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
560 {
561         if (size != 0 && n > SIZE_MAX / size)
562                 return NULL;
563         return __kmalloc(n * size, flags);
564 }
565 
566 /**
567  * kcalloc - allocate memory for an array. The memory is set to zero.
568  * @n: number of elements.
569  * @size: element size.
570  * @flags: the type of memory to allocate (see kmalloc).
571  */
572 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
573 {
574         return kmalloc_array(n, size, flags | __GFP_ZERO);
575 }
576 
577 /*
578  * kmalloc_track_caller is a special version of kmalloc that records the
579  * calling function of the routine calling it for slab leak tracking instead
580  * of just the calling function (confusing, eh?).
581  * It's useful when the call to kmalloc comes from a widely-used standard
582  * allocator where we care about the real place the memory allocation
583  * request comes from.
584  */
585 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
586         (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
587         (defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
588 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
589 #define kmalloc_track_caller(size, flags) \
590         __kmalloc_track_caller(size, flags, _RET_IP_)
591 #else
592 #define kmalloc_track_caller(size, flags) \
593         __kmalloc(size, flags)
594 #endif /* DEBUG_SLAB */
595 
596 #ifdef CONFIG_NUMA
597 /*
598  * kmalloc_node_track_caller is a special version of kmalloc_node that
599  * records the calling function of the routine calling it for slab leak
600  * tracking instead of just the calling function (confusing, eh?).
601  * It's useful when the call to kmalloc_node comes from a widely-used
602  * standard allocator where we care about the real place the memory
603  * allocation request comes from.
604  */
605 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
606         (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
607         (defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
608 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
609 #define kmalloc_node_track_caller(size, flags, node) \
610         __kmalloc_node_track_caller(size, flags, node, \
611                         _RET_IP_)
612 #else
613 #define kmalloc_node_track_caller(size, flags, node) \
614         __kmalloc_node(size, flags, node)
615 #endif
616 
617 #else /* CONFIG_NUMA */
618 
619 #define kmalloc_node_track_caller(size, flags, node) \
620         kmalloc_track_caller(size, flags)
621 
622 #endif /* CONFIG_NUMA */
623 
624 /*
625  * Shortcuts
626  */
627 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
628 {
629         return kmem_cache_alloc(k, flags | __GFP_ZERO);
630 }
631 
632 /**
633  * kzalloc - allocate memory. The memory is set to zero.
634  * @size: how many bytes of memory are required.
635  * @flags: the type of memory to allocate (see kmalloc).
636  */
637 static inline void *kzalloc(size_t size, gfp_t flags)
638 {
639         return kmalloc(size, flags | __GFP_ZERO);
640 }
641 
642 /**
643  * kzalloc_node - allocate zeroed memory from a particular memory node.
644  * @size: how many bytes of memory are required.
645  * @flags: the type of memory to allocate (see kmalloc).
646  * @node: memory node from which to allocate
647  */
648 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
649 {
650         return kmalloc_node(size, flags | __GFP_ZERO, node);
651 }
652 
653 /*
654  * Determine the size of a slab object
655  */
656 static inline unsigned int kmem_cache_size(struct kmem_cache *s)
657 {
658         return s->object_size;
659 }
660 
661 void __init kmem_cache_init_late(void);
662 
663 #endif  /* _LINUX_SLAB_H */
664 

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