slab.h 12 KB

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  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. */
  8. #ifndef _LINUX_SLAB_H
  9. #define _LINUX_SLAB_H
  10. #include <linux/gfp.h>
  11. #include <linux/types.h>
  12. /*
  13. * Flags to pass to kmem_cache_create().
  14. * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
  15. */
  16. #define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
  17. #define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */
  18. #define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */
  19. #define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */
  20. #define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
  21. #define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
  22. #define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
  23. /*
  24. * SLAB_DESTROY_BY_RCU - **WARNING** READ THIS!
  25. *
  26. * This delays freeing the SLAB page by a grace period, it does _NOT_
  27. * delay object freeing. This means that if you do kmem_cache_free()
  28. * that memory location is free to be reused at any time. Thus it may
  29. * be possible to see another object there in the same RCU grace period.
  30. *
  31. * This feature only ensures the memory location backing the object
  32. * stays valid, the trick to using this is relying on an independent
  33. * object validation pass. Something like:
  34. *
  35. * rcu_read_lock()
  36. * again:
  37. * obj = lockless_lookup(key);
  38. * if (obj) {
  39. * if (!try_get_ref(obj)) // might fail for free objects
  40. * goto again;
  41. *
  42. * if (obj->key != key) { // not the object we expected
  43. * put_ref(obj);
  44. * goto again;
  45. * }
  46. * }
  47. * rcu_read_unlock();
  48. *
  49. * See also the comment on struct slab_rcu in mm/slab.c.
  50. */
  51. #define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
  52. #define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
  53. #define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
  54. /* Flag to prevent checks on free */
  55. #ifdef CONFIG_DEBUG_OBJECTS
  56. # define SLAB_DEBUG_OBJECTS 0x00400000UL
  57. #else
  58. # define SLAB_DEBUG_OBJECTS 0x00000000UL
  59. #endif
  60. #define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
  61. /* Don't track use of uninitialized memory */
  62. #ifdef CONFIG_KMEMCHECK
  63. # define SLAB_NOTRACK 0x01000000UL
  64. #else
  65. # define SLAB_NOTRACK 0x00000000UL
  66. #endif
  67. #ifdef CONFIG_FAILSLAB
  68. # define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */
  69. #else
  70. # define SLAB_FAILSLAB 0x00000000UL
  71. #endif
  72. /* The following flags affect the page allocator grouping pages by mobility */
  73. #define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
  74. #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
  75. /*
  76. * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
  77. *
  78. * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
  79. *
  80. * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
  81. * Both make kfree a no-op.
  82. */
  83. #define ZERO_SIZE_PTR ((void *)16)
  84. #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
  85. (unsigned long)ZERO_SIZE_PTR)
  86. /*
  87. * struct kmem_cache related prototypes
  88. */
  89. void __init kmem_cache_init(void);
  90. int slab_is_available(void);
  91. struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
  92. unsigned long,
  93. void (*)(void *));
  94. void kmem_cache_destroy(struct kmem_cache *);
  95. int kmem_cache_shrink(struct kmem_cache *);
  96. void kmem_cache_free(struct kmem_cache *, void *);
  97. unsigned int kmem_cache_size(struct kmem_cache *);
  98. /*
  99. * Please use this macro to create slab caches. Simply specify the
  100. * name of the structure and maybe some flags that are listed above.
  101. *
  102. * The alignment of the struct determines object alignment. If you
  103. * f.e. add ____cacheline_aligned_in_smp to the struct declaration
  104. * then the objects will be properly aligned in SMP configurations.
  105. */
  106. #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
  107. sizeof(struct __struct), __alignof__(struct __struct),\
  108. (__flags), NULL)
  109. /*
  110. * The largest kmalloc size supported by the slab allocators is
  111. * 32 megabyte (2^25) or the maximum allocatable page order if that is
  112. * less than 32 MB.
  113. *
  114. * WARNING: Its not easy to increase this value since the allocators have
  115. * to do various tricks to work around compiler limitations in order to
  116. * ensure proper constant folding.
  117. */
  118. #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
  119. (MAX_ORDER + PAGE_SHIFT - 1) : 25)
  120. #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
  121. #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
  122. /*
  123. * Some archs want to perform DMA into kmalloc caches and need a guaranteed
  124. * alignment larger than the alignment of a 64-bit integer.
  125. * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
  126. */
  127. #ifdef ARCH_DMA_MINALIGN
  128. #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
  129. #else
  130. #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
  131. #endif
  132. /*
  133. * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
  134. * Intended for arches that get misalignment faults even for 64 bit integer
  135. * aligned buffers.
  136. */
  137. #ifndef ARCH_SLAB_MINALIGN
  138. #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
  139. #endif
  140. /*
  141. * Common kmalloc functions provided by all allocators
  142. */
  143. void * __must_check __krealloc(const void *, size_t, gfp_t);
  144. void * __must_check krealloc(const void *, size_t, gfp_t);
  145. void kfree(const void *);
  146. void kzfree(const void *);
  147. size_t ksize(const void *);
  148. /*
  149. * Allocator specific definitions. These are mainly used to establish optimized
  150. * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
  151. * selecting the appropriate general cache at compile time.
  152. *
  153. * Allocators must define at least:
  154. *
  155. * kmem_cache_alloc()
  156. * __kmalloc()
  157. * kmalloc()
  158. *
  159. * Those wishing to support NUMA must also define:
  160. *
  161. * kmem_cache_alloc_node()
  162. * kmalloc_node()
  163. *
  164. * See each allocator definition file for additional comments and
  165. * implementation notes.
  166. */
  167. #ifdef CONFIG_SLUB
  168. #include <linux/slub_def.h>
  169. #elif defined(CONFIG_SLOB)
  170. #include <linux/slob_def.h>
  171. #else
  172. #include <linux/slab_def.h>
  173. #endif
  174. /**
  175. * kmalloc_array - allocate memory for an array.
  176. * @n: number of elements.
  177. * @size: element size.
  178. * @flags: the type of memory to allocate.
  179. *
  180. * The @flags argument may be one of:
  181. *
  182. * %GFP_USER - Allocate memory on behalf of user. May sleep.
  183. *
  184. * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
  185. *
  186. * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
  187. * For example, use this inside interrupt handlers.
  188. *
  189. * %GFP_HIGHUSER - Allocate pages from high memory.
  190. *
  191. * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
  192. *
  193. * %GFP_NOFS - Do not make any fs calls while trying to get memory.
  194. *
  195. * %GFP_NOWAIT - Allocation will not sleep.
  196. *
  197. * %GFP_THISNODE - Allocate node-local memory only.
  198. *
  199. * %GFP_DMA - Allocation suitable for DMA.
  200. * Should only be used for kmalloc() caches. Otherwise, use a
  201. * slab created with SLAB_DMA.
  202. *
  203. * Also it is possible to set different flags by OR'ing
  204. * in one or more of the following additional @flags:
  205. *
  206. * %__GFP_COLD - Request cache-cold pages instead of
  207. * trying to return cache-warm pages.
  208. *
  209. * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
  210. *
  211. * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
  212. * (think twice before using).
  213. *
  214. * %__GFP_NORETRY - If memory is not immediately available,
  215. * then give up at once.
  216. *
  217. * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
  218. *
  219. * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
  220. *
  221. * There are other flags available as well, but these are not intended
  222. * for general use, and so are not documented here. For a full list of
  223. * potential flags, always refer to linux/gfp.h.
  224. */
  225. static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
  226. {
  227. if (size != 0 && n > SIZE_MAX / size)
  228. return NULL;
  229. return __kmalloc(n * size, flags);
  230. }
  231. /**
  232. * kcalloc - allocate memory for an array. The memory is set to zero.
  233. * @n: number of elements.
  234. * @size: element size.
  235. * @flags: the type of memory to allocate (see kmalloc).
  236. */
  237. static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
  238. {
  239. return kmalloc_array(n, size, flags | __GFP_ZERO);
  240. }
  241. #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
  242. /**
  243. * kmalloc_node - allocate memory from a specific node
  244. * @size: how many bytes of memory are required.
  245. * @flags: the type of memory to allocate (see kcalloc).
  246. * @node: node to allocate from.
  247. *
  248. * kmalloc() for non-local nodes, used to allocate from a specific node
  249. * if available. Equivalent to kmalloc() in the non-NUMA single-node
  250. * case.
  251. */
  252. static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
  253. {
  254. return kmalloc(size, flags);
  255. }
  256. static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
  257. {
  258. return __kmalloc(size, flags);
  259. }
  260. void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
  261. static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
  262. gfp_t flags, int node)
  263. {
  264. return kmem_cache_alloc(cachep, flags);
  265. }
  266. #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
  267. /*
  268. * kmalloc_track_caller is a special version of kmalloc that records the
  269. * calling function of the routine calling it for slab leak tracking instead
  270. * of just the calling function (confusing, eh?).
  271. * It's useful when the call to kmalloc comes from a widely-used standard
  272. * allocator where we care about the real place the memory allocation
  273. * request comes from.
  274. */
  275. #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
  276. (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
  277. extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
  278. #define kmalloc_track_caller(size, flags) \
  279. __kmalloc_track_caller(size, flags, _RET_IP_)
  280. #else
  281. #define kmalloc_track_caller(size, flags) \
  282. __kmalloc(size, flags)
  283. #endif /* DEBUG_SLAB */
  284. #ifdef CONFIG_NUMA
  285. /*
  286. * kmalloc_node_track_caller is a special version of kmalloc_node that
  287. * records the calling function of the routine calling it for slab leak
  288. * tracking instead of just the calling function (confusing, eh?).
  289. * It's useful when the call to kmalloc_node comes from a widely-used
  290. * standard allocator where we care about the real place the memory
  291. * allocation request comes from.
  292. */
  293. #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
  294. (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
  295. extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
  296. #define kmalloc_node_track_caller(size, flags, node) \
  297. __kmalloc_node_track_caller(size, flags, node, \
  298. _RET_IP_)
  299. #else
  300. #define kmalloc_node_track_caller(size, flags, node) \
  301. __kmalloc_node(size, flags, node)
  302. #endif
  303. #else /* CONFIG_NUMA */
  304. #define kmalloc_node_track_caller(size, flags, node) \
  305. kmalloc_track_caller(size, flags)
  306. #endif /* CONFIG_NUMA */
  307. /*
  308. * Shortcuts
  309. */
  310. static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
  311. {
  312. return kmem_cache_alloc(k, flags | __GFP_ZERO);
  313. }
  314. /**
  315. * kzalloc - allocate memory. The memory is set to zero.
  316. * @size: how many bytes of memory are required.
  317. * @flags: the type of memory to allocate (see kmalloc).
  318. */
  319. static inline void *kzalloc(size_t size, gfp_t flags)
  320. {
  321. return kmalloc(size, flags | __GFP_ZERO);
  322. }
  323. /**
  324. * kzalloc_node - allocate zeroed memory from a particular memory node.
  325. * @size: how many bytes of memory are required.
  326. * @flags: the type of memory to allocate (see kmalloc).
  327. * @node: memory node from which to allocate
  328. */
  329. static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
  330. {
  331. return kmalloc_node(size, flags | __GFP_ZERO, node);
  332. }
  333. void __init kmem_cache_init_late(void);
  334. #endif /* _LINUX_SLAB_H */