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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Christoph Lameter2e892f42006-12-13 00:34:23 -08002 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
3 *
Christoph Lametercde53532008-07-04 09:59:22 -07004 * (C) SGI 2006, Christoph Lameter
Christoph Lameter2e892f42006-12-13 00:34:23 -08005 * Cleaned up and restructured to ease the addition of alternative
6 * implementations of SLAB allocators.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 */
8
9#ifndef _LINUX_SLAB_H
10#define _LINUX_SLAB_H
11
Andrew Morton1b1cec42006-12-06 20:33:22 -080012#include <linux/gfp.h>
Andrew Morton1b1cec42006-12-06 20:33:22 -080013#include <linux/types.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
Christoph Lameter2e892f42006-12-13 00:34:23 -080015/*
16 * Flags to pass to kmem_cache_create().
17 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
Linus Torvalds1da177e2005-04-16 15:20:36 -070018 */
Christoph Lameter55935a32006-12-13 00:34:24 -080019#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
Christoph Lameter55935a32006-12-13 00:34:24 -080020#define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */
21#define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */
22#define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */
Christoph Lameter2e892f42006-12-13 00:34:23 -080023#define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
Christoph Lameter2e892f42006-12-13 00:34:23 -080024#define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
Christoph Lameter2e892f42006-12-13 00:34:23 -080025#define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
Peter Zijlstrad7de4c12008-11-13 20:40:12 +020026/*
27 * SLAB_DESTROY_BY_RCU - **WARNING** READ THIS!
28 *
29 * This delays freeing the SLAB page by a grace period, it does _NOT_
30 * delay object freeing. This means that if you do kmem_cache_free()
31 * that memory location is free to be reused at any time. Thus it may
32 * be possible to see another object there in the same RCU grace period.
33 *
34 * This feature only ensures the memory location backing the object
35 * stays valid, the trick to using this is relying on an independent
36 * object validation pass. Something like:
37 *
38 * rcu_read_lock()
39 * again:
40 * obj = lockless_lookup(key);
41 * if (obj) {
42 * if (!try_get_ref(obj)) // might fail for free objects
43 * goto again;
44 *
45 * if (obj->key != key) { // not the object we expected
46 * put_ref(obj);
47 * goto again;
48 * }
49 * }
50 * rcu_read_unlock();
51 *
52 * See also the comment on struct slab_rcu in mm/slab.c.
53 */
Christoph Lameter2e892f42006-12-13 00:34:23 -080054#define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
Paul Jackson101a5002006-03-24 03:16:07 -080055#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
Christoph Lameter81819f02007-05-06 14:49:36 -070056#define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
Thomas Gleixner30327ac2008-04-30 00:54:59 -070058/* Flag to prevent checks on free */
59#ifdef CONFIG_DEBUG_OBJECTS
60# define SLAB_DEBUG_OBJECTS 0x00400000UL
61#else
62# define SLAB_DEBUG_OBJECTS 0x00000000UL
63#endif
64
Catalin Marinasd5cff632009-06-11 13:22:40 +010065#define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
66
Vegard Nossum2dff4402008-05-31 15:56:17 +020067/* Don't track use of uninitialized memory */
68#ifdef CONFIG_KMEMCHECK
69# define SLAB_NOTRACK 0x01000000UL
70#else
71# define SLAB_NOTRACK 0x00000000UL
72#endif
Dmitry Monakhov4c13dd32010-02-26 09:36:12 +030073#ifdef CONFIG_FAILSLAB
74# define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */
75#else
76# define SLAB_FAILSLAB 0x00000000UL
77#endif
Vegard Nossum2dff4402008-05-31 15:56:17 +020078
Mel Gormane12ba742007-10-16 01:25:52 -070079/* The following flags affect the page allocator grouping pages by mobility */
80#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
81#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
Christoph Lameter2e892f42006-12-13 00:34:23 -080082/*
Christoph Lameter6cb8f912007-07-17 04:03:22 -070083 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
84 *
85 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
86 *
87 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
88 * Both make kfree a no-op.
89 */
90#define ZERO_SIZE_PTR ((void *)16)
91
Roland Dreier1d4ec7b2007-07-20 12:13:20 -070092#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
Christoph Lameter6cb8f912007-07-17 04:03:22 -070093 (unsigned long)ZERO_SIZE_PTR)
94
95/*
Christoph Lameter3b0efdf2012-06-13 10:24:57 -050096 * Common fields provided in kmem_cache by all slab allocators
97 * This struct is either used directly by the allocator (SLOB)
98 * or the allocator must include definitions for all fields
99 * provided in kmem_cache_common in their definition of kmem_cache.
100 *
101 * Once we can do anonymous structs (C11 standard) we could put a
102 * anonymous struct definition in these allocators so that the
103 * separate allocations in the kmem_cache structure of SLAB and
104 * SLUB is no longer needed.
105 */
106#ifdef CONFIG_SLOB
107struct kmem_cache {
108 unsigned int object_size;/* The original size of the object */
109 unsigned int size; /* The aligned/padded/added on size */
110 unsigned int align; /* Alignment as calculated */
111 unsigned long flags; /* Active flags on the slab */
112 const char *name; /* Slab name for sysfs */
113 int refcount; /* Use counter */
114 void (*ctor)(void *); /* Called on object slot creation */
115 struct list_head list; /* List of all slab caches on the system */
116};
117#endif
118
119/*
Christoph Lameter2e892f42006-12-13 00:34:23 -0800120 * struct kmem_cache related prototypes
121 */
122void __init kmem_cache_init(void);
Christoph Lameter81819f02007-05-06 14:49:36 -0700123int slab_is_available(void);
Matt Mackall10cef602006-01-08 01:01:45 -0800124
Christoph Lameter2e892f42006-12-13 00:34:23 -0800125struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
Christoph Lameterebe29732006-12-06 20:32:59 -0800126 unsigned long,
Alexey Dobriyan51cc5062008-07-25 19:45:34 -0700127 void (*)(void *));
Christoph Lameter2e892f42006-12-13 00:34:23 -0800128void kmem_cache_destroy(struct kmem_cache *);
129int kmem_cache_shrink(struct kmem_cache *);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800130void kmem_cache_free(struct kmem_cache *, void *);
131unsigned int kmem_cache_size(struct kmem_cache *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
Christoph Lameter0a31bd52007-05-06 14:49:57 -0700133/*
134 * Please use this macro to create slab caches. Simply specify the
135 * name of the structure and maybe some flags that are listed above.
136 *
137 * The alignment of the struct determines object alignment. If you
138 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
139 * then the objects will be properly aligned in SMP configurations.
140 */
141#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
142 sizeof(struct __struct), __alignof__(struct __struct),\
Paul Mundt20c2df82007-07-20 10:11:58 +0900143 (__flags), NULL)
Christoph Lameter0a31bd52007-05-06 14:49:57 -0700144
Christoph Lameter2e892f42006-12-13 00:34:23 -0800145/*
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700146 * The largest kmalloc size supported by the slab allocators is
147 * 32 megabyte (2^25) or the maximum allocatable page order if that is
148 * less than 32 MB.
149 *
150 * WARNING: Its not easy to increase this value since the allocators have
151 * to do various tricks to work around compiler limitations in order to
152 * ensure proper constant folding.
153 */
Christoph Lameterdebee072007-06-23 17:16:43 -0700154#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
155 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700156
157#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
158#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
159
Christoph Lameter90810642011-06-23 09:36:12 -0500160/*
161 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
162 * alignment larger than the alignment of a 64-bit integer.
163 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
164 */
Christoph Lameter3192b922011-06-14 16:16:36 -0500165#ifdef ARCH_DMA_MINALIGN
166#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
167#else
168#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
169#endif
170
Christoph Lameter90810642011-06-23 09:36:12 -0500171/*
172 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
173 * Intended for arches that get misalignment faults even for 64 bit integer
174 * aligned buffers.
175 */
Christoph Lameter3192b922011-06-14 16:16:36 -0500176#ifndef ARCH_SLAB_MINALIGN
177#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
178#endif
179
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700180/*
Christoph Lameter2e892f42006-12-13 00:34:23 -0800181 * Common kmalloc functions provided by all allocators
182 */
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700183void * __must_check __krealloc(const void *, size_t, gfp_t);
Pekka Enbergfd76bab2007-05-06 14:48:40 -0700184void * __must_check krealloc(const void *, size_t, gfp_t);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800185void kfree(const void *);
Johannes Weiner3ef0e5b2009-02-20 15:38:41 -0800186void kzfree(const void *);
Pekka Enbergfd76bab2007-05-06 14:48:40 -0700187size_t ksize(const void *);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800188
Christoph Lameter81cda662007-07-17 04:03:29 -0700189/*
190 * Allocator specific definitions. These are mainly used to establish optimized
191 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
192 * selecting the appropriate general cache at compile time.
193 *
194 * Allocators must define at least:
195 *
196 * kmem_cache_alloc()
197 * __kmalloc()
198 * kmalloc()
199 *
200 * Those wishing to support NUMA must also define:
201 *
202 * kmem_cache_alloc_node()
203 * kmalloc_node()
204 *
205 * See each allocator definition file for additional comments and
206 * implementation notes.
207 */
208#ifdef CONFIG_SLUB
209#include <linux/slub_def.h>
210#elif defined(CONFIG_SLOB)
211#include <linux/slob_def.h>
212#else
213#include <linux/slab_def.h>
214#endif
215
Christoph Lameter2e892f42006-12-13 00:34:23 -0800216/**
Xi Wanga8203722012-03-05 15:14:41 -0800217 * kmalloc_array - allocate memory for an array.
Christoph Lameter2e892f42006-12-13 00:34:23 -0800218 * @n: number of elements.
219 * @size: element size.
220 * @flags: the type of memory to allocate.
Paul Drynoff800590f2006-06-23 02:03:48 -0700221 *
222 * The @flags argument may be one of:
223 *
224 * %GFP_USER - Allocate memory on behalf of user. May sleep.
225 *
226 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
227 *
Paul Mundt6193a2f2007-07-15 23:38:22 -0700228 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
Paul Drynoff800590f2006-06-23 02:03:48 -0700229 * For example, use this inside interrupt handlers.
230 *
231 * %GFP_HIGHUSER - Allocate pages from high memory.
232 *
233 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
234 *
235 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
236 *
Paul Mundt6193a2f2007-07-15 23:38:22 -0700237 * %GFP_NOWAIT - Allocation will not sleep.
238 *
239 * %GFP_THISNODE - Allocate node-local memory only.
240 *
241 * %GFP_DMA - Allocation suitable for DMA.
242 * Should only be used for kmalloc() caches. Otherwise, use a
243 * slab created with SLAB_DMA.
244 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700245 * Also it is possible to set different flags by OR'ing
246 * in one or more of the following additional @flags:
247 *
248 * %__GFP_COLD - Request cache-cold pages instead of
249 * trying to return cache-warm pages.
250 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700251 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
252 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700253 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
254 * (think twice before using).
255 *
256 * %__GFP_NORETRY - If memory is not immediately available,
257 * then give up at once.
258 *
259 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
260 *
261 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
Paul Mundt6193a2f2007-07-15 23:38:22 -0700262 *
263 * There are other flags available as well, but these are not intended
264 * for general use, and so are not documented here. For a full list of
265 * potential flags, always refer to linux/gfp.h.
Paul Drynoff800590f2006-06-23 02:03:48 -0700266 */
Xi Wanga8203722012-03-05 15:14:41 -0800267static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268{
Xi Wanga3860c12012-05-31 16:26:04 -0700269 if (size != 0 && n > SIZE_MAX / size)
Paul Mundt6193a2f2007-07-15 23:38:22 -0700270 return NULL;
Xi Wanga8203722012-03-05 15:14:41 -0800271 return __kmalloc(n * size, flags);
272}
273
274/**
275 * kcalloc - allocate memory for an array. The memory is set to zero.
276 * @n: number of elements.
277 * @size: element size.
278 * @flags: the type of memory to allocate (see kmalloc).
279 */
280static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
281{
282 return kmalloc_array(n, size, flags | __GFP_ZERO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283}
284
Paul Mundt6193a2f2007-07-15 23:38:22 -0700285#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
286/**
287 * kmalloc_node - allocate memory from a specific node
288 * @size: how many bytes of memory are required.
289 * @flags: the type of memory to allocate (see kcalloc).
290 * @node: node to allocate from.
291 *
292 * kmalloc() for non-local nodes, used to allocate from a specific node
293 * if available. Equivalent to kmalloc() in the non-NUMA single-node
294 * case.
295 */
Christoph Lameter55935a32006-12-13 00:34:24 -0800296static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
297{
298 return kmalloc(size, flags);
299}
300
301static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
302{
303 return __kmalloc(size, flags);
304}
Paul Mundt6193a2f2007-07-15 23:38:22 -0700305
306void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
307
308static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
309 gfp_t flags, int node)
310{
311 return kmem_cache_alloc(cachep, flags);
312}
313#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
Christoph Lameter55935a32006-12-13 00:34:24 -0800314
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -0700315/*
316 * kmalloc_track_caller is a special version of kmalloc that records the
317 * calling function of the routine calling it for slab leak tracking instead
318 * of just the calling function (confusing, eh?).
319 * It's useful when the call to kmalloc comes from a widely-used standard
320 * allocator where we care about the real place the memory allocation
321 * request comes from.
322 */
Xiaotian Feng7adde042010-06-30 17:57:22 +0800323#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
324 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300325extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -0700326#define kmalloc_track_caller(size, flags) \
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300327 __kmalloc_track_caller(size, flags, _RET_IP_)
Christoph Lameter2e892f42006-12-13 00:34:23 -0800328#else
329#define kmalloc_track_caller(size, flags) \
330 __kmalloc(size, flags)
331#endif /* DEBUG_SLAB */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332
Manfred Spraul97e2bde2005-05-01 08:58:38 -0700333#ifdef CONFIG_NUMA
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800334/*
335 * kmalloc_node_track_caller is a special version of kmalloc_node that
336 * records the calling function of the routine calling it for slab leak
337 * tracking instead of just the calling function (confusing, eh?).
338 * It's useful when the call to kmalloc_node comes from a widely-used
339 * standard allocator where we care about the real place the memory
340 * allocation request comes from.
341 */
Xiaotian Feng7adde042010-06-30 17:57:22 +0800342#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
343 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300344extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800345#define kmalloc_node_track_caller(size, flags, node) \
346 __kmalloc_node_track_caller(size, flags, node, \
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300347 _RET_IP_)
Christoph Lameter2e892f42006-12-13 00:34:23 -0800348#else
349#define kmalloc_node_track_caller(size, flags, node) \
350 __kmalloc_node(size, flags, node)
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800351#endif
Christoph Lameter2e892f42006-12-13 00:34:23 -0800352
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800353#else /* CONFIG_NUMA */
Christoph Lameter2e892f42006-12-13 00:34:23 -0800354
355#define kmalloc_node_track_caller(size, flags, node) \
356 kmalloc_track_caller(size, flags)
357
Pascal Terjandfcd3612008-11-25 15:08:19 +0100358#endif /* CONFIG_NUMA */
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800359
Christoph Lameter81cda662007-07-17 04:03:29 -0700360/*
361 * Shortcuts
362 */
363static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
364{
365 return kmem_cache_alloc(k, flags | __GFP_ZERO);
366}
367
368/**
369 * kzalloc - allocate memory. The memory is set to zero.
370 * @size: how many bytes of memory are required.
371 * @flags: the type of memory to allocate (see kmalloc).
372 */
373static inline void *kzalloc(size_t size, gfp_t flags)
374{
375 return kmalloc(size, flags | __GFP_ZERO);
376}
377
Jeff Layton979b0fe2008-06-05 22:47:00 -0700378/**
379 * kzalloc_node - allocate zeroed memory from a particular memory node.
380 * @size: how many bytes of memory are required.
381 * @flags: the type of memory to allocate (see kmalloc).
382 * @node: memory node from which to allocate
383 */
384static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
385{
386 return kmalloc_node(size, flags | __GFP_ZERO, node);
387}
388
Pekka Enberg7e85ee02009-06-12 14:03:06 +0300389void __init kmem_cache_init_late(void);
390
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391#endif /* _LINUX_SLAB_H */