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