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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 Lameter2e892f42006-12-13 00:34:23 -080096 * struct kmem_cache related prototypes
97 */
98void __init kmem_cache_init(void);
Christoph Lameter81819f02007-05-06 14:49:36 -070099int slab_is_available(void);
Matt Mackall10cef602006-01-08 01:01:45 -0800100
Christoph Lameter2e892f42006-12-13 00:34:23 -0800101struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
Christoph Lameterebe29732006-12-06 20:32:59 -0800102 unsigned long,
Alexey Dobriyan51cc5062008-07-25 19:45:34 -0700103 void (*)(void *));
Christoph Lameter2e892f42006-12-13 00:34:23 -0800104void kmem_cache_destroy(struct kmem_cache *);
105int kmem_cache_shrink(struct kmem_cache *);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800106void kmem_cache_free(struct kmem_cache *, void *);
107unsigned int kmem_cache_size(struct kmem_cache *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
Christoph Lameter0a31bd52007-05-06 14:49:57 -0700109/*
110 * Please use this macro to create slab caches. Simply specify the
111 * name of the structure and maybe some flags that are listed above.
112 *
113 * The alignment of the struct determines object alignment. If you
114 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
115 * then the objects will be properly aligned in SMP configurations.
116 */
117#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
118 sizeof(struct __struct), __alignof__(struct __struct),\
Paul Mundt20c2df82007-07-20 10:11:58 +0900119 (__flags), NULL)
Christoph Lameter0a31bd52007-05-06 14:49:57 -0700120
Christoph Lameter2e892f42006-12-13 00:34:23 -0800121/*
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700122 * The largest kmalloc size supported by the slab allocators is
123 * 32 megabyte (2^25) or the maximum allocatable page order if that is
124 * less than 32 MB.
125 *
126 * WARNING: Its not easy to increase this value since the allocators have
127 * to do various tricks to work around compiler limitations in order to
128 * ensure proper constant folding.
129 */
Christoph Lameterdebee072007-06-23 17:16:43 -0700130#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
131 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700132
133#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
134#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
135
Christoph Lameter90810642011-06-23 09:36:12 -0500136/*
137 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
138 * alignment larger than the alignment of a 64-bit integer.
139 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
140 */
Christoph Lameter3192b922011-06-14 16:16:36 -0500141#ifdef ARCH_DMA_MINALIGN
142#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
143#else
144#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
145#endif
146
Christoph Lameter90810642011-06-23 09:36:12 -0500147/*
148 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
149 * Intended for arches that get misalignment faults even for 64 bit integer
150 * aligned buffers.
151 */
Christoph Lameter3192b922011-06-14 16:16:36 -0500152#ifndef ARCH_SLAB_MINALIGN
153#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
154#endif
155
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700156/*
Christoph Lameter2e892f42006-12-13 00:34:23 -0800157 * Common kmalloc functions provided by all allocators
158 */
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700159void * __must_check __krealloc(const void *, size_t, gfp_t);
Pekka Enbergfd76bab2007-05-06 14:48:40 -0700160void * __must_check krealloc(const void *, size_t, gfp_t);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800161void kfree(const void *);
Johannes Weiner3ef0e5b2009-02-20 15:38:41 -0800162void kzfree(const void *);
Pekka Enbergfd76bab2007-05-06 14:48:40 -0700163size_t ksize(const void *);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800164
Christoph Lameter81cda662007-07-17 04:03:29 -0700165/*
166 * Allocator specific definitions. These are mainly used to establish optimized
167 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
168 * selecting the appropriate general cache at compile time.
169 *
170 * Allocators must define at least:
171 *
172 * kmem_cache_alloc()
173 * __kmalloc()
174 * kmalloc()
175 *
176 * Those wishing to support NUMA must also define:
177 *
178 * kmem_cache_alloc_node()
179 * kmalloc_node()
180 *
181 * See each allocator definition file for additional comments and
182 * implementation notes.
183 */
184#ifdef CONFIG_SLUB
185#include <linux/slub_def.h>
186#elif defined(CONFIG_SLOB)
187#include <linux/slob_def.h>
188#else
189#include <linux/slab_def.h>
190#endif
191
Christoph Lameter2e892f42006-12-13 00:34:23 -0800192/**
193 * kcalloc - allocate memory for an array. The memory is set to zero.
194 * @n: number of elements.
195 * @size: element size.
196 * @flags: the type of memory to allocate.
Paul Drynoff800590f2006-06-23 02:03:48 -0700197 *
198 * The @flags argument may be one of:
199 *
200 * %GFP_USER - Allocate memory on behalf of user. May sleep.
201 *
202 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
203 *
Paul Mundt6193a2f2007-07-15 23:38:22 -0700204 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
Paul Drynoff800590f2006-06-23 02:03:48 -0700205 * For example, use this inside interrupt handlers.
206 *
207 * %GFP_HIGHUSER - Allocate pages from high memory.
208 *
209 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
210 *
211 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
212 *
Paul Mundt6193a2f2007-07-15 23:38:22 -0700213 * %GFP_NOWAIT - Allocation will not sleep.
214 *
215 * %GFP_THISNODE - Allocate node-local memory only.
216 *
217 * %GFP_DMA - Allocation suitable for DMA.
218 * Should only be used for kmalloc() caches. Otherwise, use a
219 * slab created with SLAB_DMA.
220 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700221 * Also it is possible to set different flags by OR'ing
222 * in one or more of the following additional @flags:
223 *
224 * %__GFP_COLD - Request cache-cold pages instead of
225 * trying to return cache-warm pages.
226 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700227 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
228 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700229 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
230 * (think twice before using).
231 *
232 * %__GFP_NORETRY - If memory is not immediately available,
233 * then give up at once.
234 *
235 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
236 *
237 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
Paul Mundt6193a2f2007-07-15 23:38:22 -0700238 *
239 * There are other flags available as well, but these are not intended
240 * for general use, and so are not documented here. For a full list of
241 * potential flags, always refer to linux/gfp.h.
Paul Drynoff800590f2006-06-23 02:03:48 -0700242 */
Paul Mundt6193a2f2007-07-15 23:38:22 -0700243static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
Milton Miller9ca908f2008-07-23 21:28:20 -0700245 if (size != 0 && n > ULONG_MAX / size)
Paul Mundt6193a2f2007-07-15 23:38:22 -0700246 return NULL;
Christoph Lameter81cda662007-07-17 04:03:29 -0700247 return __kmalloc(n * size, flags | __GFP_ZERO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248}
249
Paul Mundt6193a2f2007-07-15 23:38:22 -0700250#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
251/**
252 * kmalloc_node - allocate memory from a specific node
253 * @size: how many bytes of memory are required.
254 * @flags: the type of memory to allocate (see kcalloc).
255 * @node: node to allocate from.
256 *
257 * kmalloc() for non-local nodes, used to allocate from a specific node
258 * if available. Equivalent to kmalloc() in the non-NUMA single-node
259 * case.
260 */
Christoph Lameter55935a32006-12-13 00:34:24 -0800261static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
262{
263 return kmalloc(size, flags);
264}
265
266static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
267{
268 return __kmalloc(size, flags);
269}
Paul Mundt6193a2f2007-07-15 23:38:22 -0700270
271void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
272
273static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
274 gfp_t flags, int node)
275{
276 return kmem_cache_alloc(cachep, flags);
277}
278#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
Christoph Lameter55935a32006-12-13 00:34:24 -0800279
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -0700280/*
281 * kmalloc_track_caller is a special version of kmalloc that records the
282 * calling function of the routine calling it for slab leak tracking instead
283 * of just the calling function (confusing, eh?).
284 * It's useful when the call to kmalloc comes from a widely-used standard
285 * allocator where we care about the real place the memory allocation
286 * request comes from.
287 */
Xiaotian Feng7adde042010-06-30 17:57:22 +0800288#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
289 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300290extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -0700291#define kmalloc_track_caller(size, flags) \
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300292 __kmalloc_track_caller(size, flags, _RET_IP_)
Christoph Lameter2e892f42006-12-13 00:34:23 -0800293#else
294#define kmalloc_track_caller(size, flags) \
295 __kmalloc(size, flags)
296#endif /* DEBUG_SLAB */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297
Manfred Spraul97e2bde2005-05-01 08:58:38 -0700298#ifdef CONFIG_NUMA
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800299/*
300 * kmalloc_node_track_caller is a special version of kmalloc_node that
301 * records the calling function of the routine calling it for slab leak
302 * tracking instead of just the calling function (confusing, eh?).
303 * It's useful when the call to kmalloc_node comes from a widely-used
304 * standard allocator where we care about the real place the memory
305 * allocation request comes from.
306 */
Xiaotian Feng7adde042010-06-30 17:57:22 +0800307#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
308 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300309extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800310#define kmalloc_node_track_caller(size, flags, node) \
311 __kmalloc_node_track_caller(size, flags, node, \
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300312 _RET_IP_)
Christoph Lameter2e892f42006-12-13 00:34:23 -0800313#else
314#define kmalloc_node_track_caller(size, flags, node) \
315 __kmalloc_node(size, flags, node)
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800316#endif
Christoph Lameter2e892f42006-12-13 00:34:23 -0800317
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800318#else /* CONFIG_NUMA */
Christoph Lameter2e892f42006-12-13 00:34:23 -0800319
320#define kmalloc_node_track_caller(size, flags, node) \
321 kmalloc_track_caller(size, flags)
322
Pascal Terjandfcd3612008-11-25 15:08:19 +0100323#endif /* CONFIG_NUMA */
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800324
Christoph Lameter81cda662007-07-17 04:03:29 -0700325/*
326 * Shortcuts
327 */
328static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
329{
330 return kmem_cache_alloc(k, flags | __GFP_ZERO);
331}
332
333/**
334 * kzalloc - allocate memory. The memory is set to zero.
335 * @size: how many bytes of memory are required.
336 * @flags: the type of memory to allocate (see kmalloc).
337 */
338static inline void *kzalloc(size_t size, gfp_t flags)
339{
340 return kmalloc(size, flags | __GFP_ZERO);
341}
342
Jeff Layton979b0fe2008-06-05 22:47:00 -0700343/**
344 * kzalloc_node - allocate zeroed memory from a particular memory node.
345 * @size: how many bytes of memory are required.
346 * @flags: the type of memory to allocate (see kmalloc).
347 * @node: memory node from which to allocate
348 */
349static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
350{
351 return kmalloc_node(size, flags | __GFP_ZERO, node);
352}
353
Pekka Enberg7e85ee02009-06-12 14:03:06 +0300354void __init kmem_cache_init_late(void);
355
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356#endif /* _LINUX_SLAB_H */