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 #include <linux/percpu-refcount.h>
20
21
22 /*
23 * Flags to pass to kmem_cache_create().
24 * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
25 */
26 /* DEBUG: Perform (expensive) checks on alloc/free */
27 #define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
28 /* DEBUG: Red zone objs in a cache */
29 #define SLAB_RED_ZONE ((slab_flags_t __force)0x00000400U)
30 /* DEBUG: Poison objects */
31 #define SLAB_POISON ((slab_flags_t __force)0x00000800U)
32 /* Align objs on cache lines */
33 #define SLAB_HWCACHE_ALIGN ((slab_flags_t __force)0x00002000U)
34 /* Use GFP_DMA memory */
35 #define SLAB_CACHE_DMA ((slab_flags_t __force)0x00004000U)
36 /* Use GFP_DMA32 memory */
37 #define SLAB_CACHE_DMA32 ((slab_flags_t __force)0x00008000U)
38 /* DEBUG: Store the last owner for bug hunting */
39 #define SLAB_STORE_USER ((slab_flags_t __force)0x00010000U)
40 /* Panic if kmem_cache_create() fails */
41 #define SLAB_PANIC ((slab_flags_t __force)0x00040000U)
42 /*
43 * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
44 *
45 * This delays freeing the SLAB page by a grace period, it does _NOT_
46 * delay object freeing. This means that if you do kmem_cache_free()
47 * that memory location is free to be reused at any time. Thus it may
48 * be possible to see another object there in the same RCU grace period.
49 *
50 * This feature only ensures the memory location backing the object
51 * stays valid, the trick to using this is relying on an independent
52 * object validation pass. Something like:
53 *
54 * rcu_read_lock()
55 * again:
56 * obj = lockless_lookup(key);
57 * if (obj) {
58 * if (!try_get_ref(obj)) // might fail for free objects
59 * goto again;
60 *
61 * if (obj->key != key) { // not the object we expected
62 * put_ref(obj);
63 * goto again;
64 * }
65 * }
66 * rcu_read_unlock();
67 *
68 * This is useful if we need to approach a kernel structure obliquely,
69 * from its address obtained without the usual locking. We can lock
70 * the structure to stabilize it and check it's still at the given address,
71 * only if we can be sure that the memory has not been meanwhile reused
72 * for some other kind of object (which our subsystem's lock might corrupt).
73 *
74 * rcu_read_lock before reading the address, then rcu_read_unlock after
75 * taking the spinlock within the structure expected at that address.
76 *
77 * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
78 */
79 /* Defer freeing slabs to RCU */
80 #define SLAB_TYPESAFE_BY_RCU ((slab_flags_t __force)0x00080000U)
81 /* Spread some memory over cpuset */
82 #define SLAB_MEM_SPREAD ((slab_flags_t __force)0x00100000U)
83 /* Trace allocations and frees */
84 #define SLAB_TRACE ((slab_flags_t __force)0x00200000U)
85
86 /* Flag to prevent checks on free */
87 #ifdef CONFIG_DEBUG_OBJECTS
88 # define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00400000U)
89 #else
90 # define SLAB_DEBUG_OBJECTS 0
91 #endif
92
93 /* Avoid kmemleak tracing */
94 #define SLAB_NOLEAKTRACE ((slab_flags_t __force)0x00800000U)
95
96 /* Fault injection mark */
97 #ifdef CONFIG_FAILSLAB
98 # define SLAB_FAILSLAB ((slab_flags_t __force)0x02000000U)
99 #else
100 # define SLAB_FAILSLAB 0
101 #endif
102 /* Account to memcg */
103 #ifdef CONFIG_MEMCG_KMEM
104 # define SLAB_ACCOUNT ((slab_flags_t __force)0x04000000U)
105 #else
106 # define SLAB_ACCOUNT 0
107 #endif
108
109 #ifdef CONFIG_KASAN
110 #define SLAB_KASAN ((slab_flags_t __force)0x08000000U)
111 #else
112 #define SLAB_KASAN 0
113 #endif
114
115 /* The following flags affect the page allocator grouping pages by mobility */
116 /* Objects are reclaimable */
117 #define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000U)
118 #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
119
120 /* Slab deactivation flag */
121 #define SLAB_DEACTIVATED ((slab_flags_t __force)0x10000000U)
122
123 /*
124 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
125 *
126 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
127 *
128 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
129 * Both make kfree a no-op.
130 */
131 #define ZERO_SIZE_PTR ((void *)16)
132
133 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
134 (unsigned long)ZERO_SIZE_PTR)
135
136 #include <linux/kasan.h>
137
138 struct mem_cgroup;
139 /*
140 * struct kmem_cache related prototypes
141 */
142 void __init kmem_cache_init(void);
143 bool slab_is_available(void);
144
145 extern bool usercopy_fallback;
146
147 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
148 unsigned int align, slab_flags_t flags,
149 void (*ctor)(void *));
150 struct kmem_cache *kmem_cache_create_usercopy(const char *name,
151 unsigned int size, unsigned int align,
152 slab_flags_t flags,
153 unsigned int useroffset, unsigned int usersize,
154 void (*ctor)(void *));
155 void kmem_cache_destroy(struct kmem_cache *);
156 int kmem_cache_shrink(struct kmem_cache *);
157
158 void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *);
159 void memcg_deactivate_kmem_caches(struct mem_cgroup *, struct mem_cgroup *);
160
161 /*
162 * Please use this macro to create slab caches. Simply specify the
163 * name of the structure and maybe some flags that are listed above.
164 *
165 * The alignment of the struct determines object alignment. If you
166 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
167 * then the objects will be properly aligned in SMP configurations.
168 */
169 #define KMEM_CACHE(__struct, __flags) \
170 kmem_cache_create(#__struct, sizeof(struct __struct), \
171 __alignof__(struct __struct), (__flags), NULL)
172
173 /*
174 * To whitelist a single field for copying to/from usercopy, use this
175 * macro instead for KMEM_CACHE() above.
176 */
177 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \
178 kmem_cache_create_usercopy(#__struct, \
179 sizeof(struct __struct), \
180 __alignof__(struct __struct), (__flags), \
181 offsetof(struct __struct, __field), \
182 sizeof_field(struct __struct, __field), NULL)
183
184 /*
185 * Common kmalloc functions provided by all allocators
186 */
187 void * __must_check __krealloc(const void *, size_t, gfp_t);
188 void * __must_check krealloc(const void *, size_t, gfp_t);
189 void kfree(const void *);
190 void kzfree(const void *);
191 size_t __ksize(const void *);
192 size_t ksize(const void *);
193
194 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
195 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
196 bool to_user);
197 #else
198 static inline void __check_heap_object(const void *ptr, unsigned long n,
199 struct page *page, bool to_user) { }
200 #endif
201
202 /*
203 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
204 * alignment larger than the alignment of a 64-bit integer.
205 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
206 */
207 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
208 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
209 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
210 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
211 #else
212 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
213 #endif
214
215 /*
216 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
217 * Intended for arches that get misalignment faults even for 64 bit integer
218 * aligned buffers.
219 */
220 #ifndef ARCH_SLAB_MINALIGN
221 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
222 #endif
223
224 /*
225 * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
226 * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
227 * aligned pointers.
228 */
229 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
230 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
231 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
232
233 /*
234 * Kmalloc array related definitions
235 */
236
237 #ifdef CONFIG_SLAB
238 /*
239 * The largest kmalloc size supported by the SLAB allocators is
240 * 32 megabyte (2^25) or the maximum allocatable page order if that is
241 * less than 32 MB.
242 *
243 * WARNING: Its not easy to increase this value since the allocators have
244 * to do various tricks to work around compiler limitations in order to
245 * ensure proper constant folding.
246 */
247 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
248 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
249 #define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH
250 #ifndef KMALLOC_SHIFT_LOW
251 #define KMALLOC_SHIFT_LOW 5
252 #endif
253 #endif
254
255 #ifdef CONFIG_SLUB
256 /*
257 * SLUB directly allocates requests fitting in to an order-1 page
258 * (PAGE_SIZE*2). Larger requests are passed to the page allocator.
259 */
260 #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
261 #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
262 #ifndef KMALLOC_SHIFT_LOW
263 #define KMALLOC_SHIFT_LOW 3
264 #endif
265 #endif
266
267 #ifdef CONFIG_SLOB
268 /*
269 * SLOB passes all requests larger than one page to the page allocator.
270 * No kmalloc array is necessary since objects of different sizes can
271 * be allocated from the same page.
272 */
273 #define KMALLOC_SHIFT_HIGH PAGE_SHIFT
274 #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
275 #ifndef KMALLOC_SHIFT_LOW
276 #define KMALLOC_SHIFT_LOW 3
277 #endif
278 #endif
279
280 /* Maximum allocatable size */
281 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
282 /* Maximum size for which we actually use a slab cache */
283 #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
284 /* Maximum order allocatable via the slab allocagtor */
285 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
286
287 /*
288 * Kmalloc subsystem.
289 */
290 #ifndef KMALLOC_MIN_SIZE
291 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
292 #endif
293
294 /*
295 * This restriction comes from byte sized index implementation.
296 * Page size is normally 2^12 bytes and, in this case, if we want to use
297 * byte sized index which can represent 2^8 entries, the size of the object
298 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
299 * If minimum size of kmalloc is less than 16, we use it as minimum object
300 * size and give up to use byte sized index.
301 */
302 #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
303 (KMALLOC_MIN_SIZE) : 16)
304
305 /*
306 * Whenever changing this, take care of that kmalloc_type() and
307 * create_kmalloc_caches() still work as intended.
308 */
309 enum kmalloc_cache_type {
310 KMALLOC_NORMAL = 0,
311 KMALLOC_RECLAIM,
312 #ifdef CONFIG_ZONE_DMA
313 KMALLOC_DMA,
314 #endif
315 NR_KMALLOC_TYPES
316 };
317
318 #ifndef CONFIG_SLOB
319 extern struct kmem_cache *
320 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
321
322 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
323 {
324 #ifdef CONFIG_ZONE_DMA
325 /*
326 * The most common case is KMALLOC_NORMAL, so test for it
327 * with a single branch for both flags.
328 */
329 if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0))
330 return KMALLOC_NORMAL;
331
332 /*
333 * At least one of the flags has to be set. If both are, __GFP_DMA
334 * is more important.
335 */
336 return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM;
337 #else
338 return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL;
339 #endif
340 }
341
342 /*
343 * Figure out which kmalloc slab an allocation of a certain size
344 * belongs to.
345 * 0 = zero alloc
346 * 1 = 65 .. 96 bytes
347 * 2 = 129 .. 192 bytes
348 * n = 2^(n-1)+1 .. 2^n
349 */
350 static __always_inline unsigned int kmalloc_index(size_t size)
351 {
352 if (!size)
353 return 0;
354
355 if (size <= KMALLOC_MIN_SIZE)
356 return KMALLOC_SHIFT_LOW;
357
358 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
359 return 1;
360 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
361 return 2;
362 if (size <= 8) return 3;
363 if (size <= 16) return 4;
364 if (size <= 32) return 5;
365 if (size <= 64) return 6;
366 if (size <= 128) return 7;
367 if (size <= 256) return 8;
368 if (size <= 512) return 9;
369 if (size <= 1024) return 10;
370 if (size <= 2 * 1024) return 11;
371 if (size <= 4 * 1024) return 12;
372 if (size <= 8 * 1024) return 13;
373 if (size <= 16 * 1024) return 14;
374 if (size <= 32 * 1024) return 15;
375 if (size <= 64 * 1024) return 16;
376 if (size <= 128 * 1024) return 17;
377 if (size <= 256 * 1024) return 18;
378 if (size <= 512 * 1024) return 19;
379 if (size <= 1024 * 1024) return 20;
380 if (size <= 2 * 1024 * 1024) return 21;
381 if (size <= 4 * 1024 * 1024) return 22;
382 if (size <= 8 * 1024 * 1024) return 23;
383 if (size <= 16 * 1024 * 1024) return 24;
384 if (size <= 32 * 1024 * 1024) return 25;
385 if (size <= 64 * 1024 * 1024) return 26;
386 BUG();
387
388 /* Will never be reached. Needed because the compiler may complain */
389 return -1;
390 }
391 #endif /* !CONFIG_SLOB */
392
393 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
394 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
395 void kmem_cache_free(struct kmem_cache *, void *);
396
397 /*
398 * Bulk allocation and freeing operations. These are accelerated in an
399 * allocator specific way to avoid taking locks repeatedly or building
400 * metadata structures unnecessarily.
401 *
402 * Note that interrupts must be enabled when calling these functions.
403 */
404 void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
405 int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
406
407 /*
408 * Caller must not use kfree_bulk() on memory not originally allocated
409 * by kmalloc(), because the SLOB allocator cannot handle this.
410 */
411 static __always_inline void kfree_bulk(size_t size, void **p)
412 {
413 kmem_cache_free_bulk(NULL, size, p);
414 }
415
416 #ifdef CONFIG_NUMA
417 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
418 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
419 #else
420 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
421 {
422 return __kmalloc(size, flags);
423 }
424
425 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
426 {
427 return kmem_cache_alloc(s, flags);
428 }
429 #endif
430
431 #ifdef CONFIG_TRACING
432 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
433
434 #ifdef CONFIG_NUMA
435 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
436 gfp_t gfpflags,
437 int node, size_t size) __assume_slab_alignment __malloc;
438 #else
439 static __always_inline void *
440 kmem_cache_alloc_node_trace(struct kmem_cache *s,
441 gfp_t gfpflags,
442 int node, size_t size)
443 {
444 return kmem_cache_alloc_trace(s, gfpflags, size);
445 }
446 #endif /* CONFIG_NUMA */
447
448 #else /* CONFIG_TRACING */
449 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
450 gfp_t flags, size_t size)
451 {
452 void *ret = kmem_cache_alloc(s, flags);
453
454 ret = kasan_kmalloc(s, ret, size, flags);
455 return ret;
456 }
457
458 static __always_inline void *
459 kmem_cache_alloc_node_trace(struct kmem_cache *s,
460 gfp_t gfpflags,
461 int node, size_t size)
462 {
463 void *ret = kmem_cache_alloc_node(s, gfpflags, node);
464
465 ret = kasan_kmalloc(s, ret, size, gfpflags);
466 return ret;
467 }
468 #endif /* CONFIG_TRACING */
469
470 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
471
472 #ifdef CONFIG_TRACING
473 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
474 #else
475 static __always_inline void *
476 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
477 {
478 return kmalloc_order(size, flags, order);
479 }
480 #endif
481
482 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
483 {
484 unsigned int order = get_order(size);
485 return kmalloc_order_trace(size, flags, order);
486 }
487
488 /**
489 * kmalloc - allocate memory
490 * @size: how many bytes of memory are required.
491 * @flags: the type of memory to allocate.
492 *
493 * kmalloc is the normal method of allocating memory
494 * for objects smaller than page size in the kernel.
495 *
496 * The @flags argument may be one of the GFP flags defined at
497 * include/linux/gfp.h and described at
498 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
499 *
500 * The recommended usage of the @flags is described at
501 * :ref:`Documentation/core-api/memory-allocation.rst <memory-allocation>`
502 *
503 * Below is a brief outline of the most useful GFP flags
504 *
505 * %GFP_KERNEL
506 * Allocate normal kernel ram. May sleep.
507 *
508 * %GFP_NOWAIT
509 * Allocation will not sleep.
510 *
511 * %GFP_ATOMIC
512 * Allocation will not sleep. May use emergency pools.
513 *
514 * %GFP_HIGHUSER
515 * Allocate memory from high memory on behalf of user.
516 *
517 * Also it is possible to set different flags by OR'ing
518 * in one or more of the following additional @flags:
519 *
520 * %__GFP_HIGH
521 * This allocation has high priority and may use emergency pools.
522 *
523 * %__GFP_NOFAIL
524 * Indicate that this allocation is in no way allowed to fail
525 * (think twice before using).
526 *
527 * %__GFP_NORETRY
528 * If memory is not immediately available,
529 * then give up at once.
530 *
531 * %__GFP_NOWARN
532 * If allocation fails, don't issue any warnings.
533 *
534 * %__GFP_RETRY_MAYFAIL
535 * Try really hard to succeed the allocation but fail
536 * eventually.
537 */
538 static __always_inline void *kmalloc(size_t size, gfp_t flags)
539 {
540 if (__builtin_constant_p(size)) {
541 #ifndef CONFIG_SLOB
542 unsigned int index;
543 #endif
544 if (size > KMALLOC_MAX_CACHE_SIZE)
545 return kmalloc_large(size, flags);
546 #ifndef CONFIG_SLOB
547 index = kmalloc_index(size);
548
549 if (!index)
550 return ZERO_SIZE_PTR;
551
552 return kmem_cache_alloc_trace(
553 kmalloc_caches[kmalloc_type(flags)][index],
554 flags, size);
555 #endif
556 }
557 return __kmalloc(size, flags);
558 }
559
560 /*
561 * Determine size used for the nth kmalloc cache.
562 * return size or 0 if a kmalloc cache for that
563 * size does not exist
564 */
565 static __always_inline unsigned int kmalloc_size(unsigned int n)
566 {
567 #ifndef CONFIG_SLOB
568 if (n > 2)
569 return 1U << n;
570
571 if (n == 1 && KMALLOC_MIN_SIZE <= 32)
572 return 96;
573
574 if (n == 2 && KMALLOC_MIN_SIZE <= 64)
575 return 192;
576 #endif
577 return 0;
578 }
579
580 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
581 {
582 #ifndef CONFIG_SLOB
583 if (__builtin_constant_p(size) &&
584 size <= KMALLOC_MAX_CACHE_SIZE) {
585 unsigned int i = kmalloc_index(size);
586
587 if (!i)
588 return ZERO_SIZE_PTR;
589
590 return kmem_cache_alloc_node_trace(
591 kmalloc_caches[kmalloc_type(flags)][i],
592 flags, node, size);
593 }
594 #endif
595 return __kmalloc_node(size, flags, node);
596 }
597
598 struct memcg_cache_array {
599 struct rcu_head rcu;
600 struct kmem_cache *entries[0];
601 };
602
603 /*
604 * This is the main placeholder for memcg-related information in kmem caches.
605 * Both the root cache and the child caches will have it. For the root cache,
606 * this will hold a dynamically allocated array large enough to hold
607 * information about the currently limited memcgs in the system. To allow the
608 * array to be accessed without taking any locks, on relocation we free the old
609 * version only after a grace period.
610 *
611 * Root and child caches hold different metadata.
612 *
613 * @root_cache: Common to root and child caches. NULL for root, pointer to
614 * the root cache for children.
615 *
616 * The following fields are specific to root caches.
617 *
618 * @memcg_caches: kmemcg ID indexed table of child caches. This table is
619 * used to index child cachces during allocation and cleared
620 * early during shutdown.
621 *
622 * @root_caches_node: List node for slab_root_caches list.
623 *
624 * @children: List of all child caches. While the child caches are also
625 * reachable through @memcg_caches, a child cache remains on
626 * this list until it is actually destroyed.
627 *
628 * The following fields are specific to child caches.
629 *
630 * @memcg: Pointer to the memcg this cache belongs to.
631 *
632 * @children_node: List node for @root_cache->children list.
633 *
634 * @kmem_caches_node: List node for @memcg->kmem_caches list.
635 */
636 struct memcg_cache_params {
637 struct kmem_cache *root_cache;
638 union {
639 struct {
640 struct memcg_cache_array __rcu *memcg_caches;
641 struct list_head __root_caches_node;
642 struct list_head children;
643 bool dying;
644 };
645 struct {
646 struct mem_cgroup *memcg;
647 struct list_head children_node;
648 struct list_head kmem_caches_node;
649 struct percpu_ref refcnt;
650
651 void (*work_fn)(struct kmem_cache *);
652 union {
653 struct rcu_head rcu_head;
654 struct work_struct work;
655 };
656 };
657 };
658 };
659
660 int memcg_update_all_caches(int num_memcgs);
661
662 /**
663 * kmalloc_array - allocate memory for an array.
664 * @n: number of elements.
665 * @size: element size.
666 * @flags: the type of memory to allocate (see kmalloc).
667 */
668 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
669 {
670 size_t bytes;
671
672 if (unlikely(check_mul_overflow(n, size, &bytes)))
673 return NULL;
674 if (__builtin_constant_p(n) && __builtin_constant_p(size))
675 return kmalloc(bytes, flags);
676 return __kmalloc(bytes, flags);
677 }
678
679 /**
680 * kcalloc - allocate memory for an array. The memory is set to zero.
681 * @n: number of elements.
682 * @size: element size.
683 * @flags: the type of memory to allocate (see kmalloc).
684 */
685 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
686 {
687 return kmalloc_array(n, size, flags | __GFP_ZERO);
688 }
689
690 /*
691 * kmalloc_track_caller is a special version of kmalloc that records the
692 * calling function of the routine calling it for slab leak tracking instead
693 * of just the calling function (confusing, eh?).
694 * It's useful when the call to kmalloc comes from a widely-used standard
695 * allocator where we care about the real place the memory allocation
696 * request comes from.
697 */
698 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
699 #define kmalloc_track_caller(size, flags) \
700 __kmalloc_track_caller(size, flags, _RET_IP_)
701
702 static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
703 int node)
704 {
705 size_t bytes;
706
707 if (unlikely(check_mul_overflow(n, size, &bytes)))
708 return NULL;
709 if (__builtin_constant_p(n) && __builtin_constant_p(size))
710 return kmalloc_node(bytes, flags, node);
711 return __kmalloc_node(bytes, flags, node);
712 }
713
714 static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
715 {
716 return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
717 }
718
719
720 #ifdef CONFIG_NUMA
721 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
722 #define kmalloc_node_track_caller(size, flags, node) \
723 __kmalloc_node_track_caller(size, flags, node, \
724 _RET_IP_)
725
726 #else /* CONFIG_NUMA */
727
728 #define kmalloc_node_track_caller(size, flags, node) \
729 kmalloc_track_caller(size, flags)
730
731 #endif /* CONFIG_NUMA */
732
733 /*
734 * Shortcuts
735 */
736 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
737 {
738 return kmem_cache_alloc(k, flags | __GFP_ZERO);
739 }
740
741 /**
742 * kzalloc - allocate memory. The memory is set to zero.
743 * @size: how many bytes of memory are required.
744 * @flags: the type of memory to allocate (see kmalloc).
745 */
746 static inline void *kzalloc(size_t size, gfp_t flags)
747 {
748 return kmalloc(size, flags | __GFP_ZERO);
749 }
750
751 /**
752 * kzalloc_node - allocate zeroed memory from a particular memory node.
753 * @size: how many bytes of memory are required.
754 * @flags: the type of memory to allocate (see kmalloc).
755 * @node: memory node from which to allocate
756 */
757 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
758 {
759 return kmalloc_node(size, flags | __GFP_ZERO, node);
760 }
761
762 unsigned int kmem_cache_size(struct kmem_cache *s);
763 void __init kmem_cache_init_late(void);
764
765 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
766 int slab_prepare_cpu(unsigned int cpu);
767 int slab_dead_cpu(unsigned int cpu);
768 #else
769 #define slab_prepare_cpu NULL
770 #define slab_dead_cpu NULL
771 #endif
772
773 #endif /* _LINUX_SLAB_H */
774
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