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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 *);
108const char *kmem_cache_name(struct kmem_cache *);
Christoph Lameter55935a32006-12-13 00:34:24 -0800109int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
Christoph Lameter0a31bd52007-05-06 14:49:57 -0700111/*
112 * Please use this macro to create slab caches. Simply specify the
113 * name of the structure and maybe some flags that are listed above.
114 *
115 * The alignment of the struct determines object alignment. If you
116 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
117 * then the objects will be properly aligned in SMP configurations.
118 */
119#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
120 sizeof(struct __struct), __alignof__(struct __struct),\
Paul Mundt20c2df82007-07-20 10:11:58 +0900121 (__flags), NULL)
Christoph Lameter0a31bd52007-05-06 14:49:57 -0700122
Christoph Lameter2e892f42006-12-13 00:34:23 -0800123/*
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700124 * The largest kmalloc size supported by the slab allocators is
125 * 32 megabyte (2^25) or the maximum allocatable page order if that is
126 * less than 32 MB.
127 *
128 * WARNING: Its not easy to increase this value since the allocators have
129 * to do various tricks to work around compiler limitations in order to
130 * ensure proper constant folding.
131 */
Christoph Lameterdebee072007-06-23 17:16:43 -0700132#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
133 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
Christoph Lameter0aa817f2007-05-16 22:11:01 -0700134
135#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
136#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
137
138/*
Christoph Lameter2e892f42006-12-13 00:34:23 -0800139 * Common kmalloc functions provided by all allocators
140 */
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700141void * __must_check __krealloc(const void *, size_t, gfp_t);
Pekka Enbergfd76bab2007-05-06 14:48:40 -0700142void * __must_check krealloc(const void *, size_t, gfp_t);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800143void kfree(const void *);
Johannes Weiner3ef0e5b2009-02-20 15:38:41 -0800144void kzfree(const void *);
Pekka Enbergfd76bab2007-05-06 14:48:40 -0700145size_t ksize(const void *);
Christoph Lameter2e892f42006-12-13 00:34:23 -0800146
Christoph Lameter81cda662007-07-17 04:03:29 -0700147/*
148 * Allocator specific definitions. These are mainly used to establish optimized
149 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
150 * selecting the appropriate general cache at compile time.
151 *
152 * Allocators must define at least:
153 *
154 * kmem_cache_alloc()
155 * __kmalloc()
156 * kmalloc()
157 *
158 * Those wishing to support NUMA must also define:
159 *
160 * kmem_cache_alloc_node()
161 * kmalloc_node()
162 *
163 * See each allocator definition file for additional comments and
164 * implementation notes.
165 */
166#ifdef CONFIG_SLUB
167#include <linux/slub_def.h>
168#elif defined(CONFIG_SLOB)
169#include <linux/slob_def.h>
170#else
171#include <linux/slab_def.h>
172#endif
173
Christoph Lameter2e892f42006-12-13 00:34:23 -0800174/**
175 * kcalloc - allocate memory for an array. The memory is set to zero.
176 * @n: number of elements.
177 * @size: element size.
178 * @flags: the type of memory to allocate.
Paul Drynoff800590f2006-06-23 02:03:48 -0700179 *
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 *
Paul Mundt6193a2f2007-07-15 23:38:22 -0700186 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
Paul Drynoff800590f2006-06-23 02:03:48 -0700187 * 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 *
Paul Mundt6193a2f2007-07-15 23:38:22 -0700195 * %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 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700203 * 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 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700209 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
210 *
Paul Drynoff800590f2006-06-23 02:03:48 -0700211 * %__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.
Paul Mundt6193a2f2007-07-15 23:38:22 -0700220 *
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.
Paul Drynoff800590f2006-06-23 02:03:48 -0700224 */
Paul Mundt6193a2f2007-07-15 23:38:22 -0700225static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226{
Milton Miller9ca908f2008-07-23 21:28:20 -0700227 if (size != 0 && n > ULONG_MAX / size)
Paul Mundt6193a2f2007-07-15 23:38:22 -0700228 return NULL;
Christoph Lameter81cda662007-07-17 04:03:29 -0700229 return __kmalloc(n * size, flags | __GFP_ZERO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
Paul Mundt6193a2f2007-07-15 23:38:22 -0700232#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
233/**
234 * kmalloc_node - allocate memory from a specific node
235 * @size: how many bytes of memory are required.
236 * @flags: the type of memory to allocate (see kcalloc).
237 * @node: node to allocate from.
238 *
239 * kmalloc() for non-local nodes, used to allocate from a specific node
240 * if available. Equivalent to kmalloc() in the non-NUMA single-node
241 * case.
242 */
Christoph Lameter55935a32006-12-13 00:34:24 -0800243static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
244{
245 return kmalloc(size, flags);
246}
247
248static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
249{
250 return __kmalloc(size, flags);
251}
Paul Mundt6193a2f2007-07-15 23:38:22 -0700252
253void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
254
255static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
256 gfp_t flags, int node)
257{
258 return kmem_cache_alloc(cachep, flags);
259}
260#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
Christoph Lameter55935a32006-12-13 00:34:24 -0800261
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -0700262/*
263 * kmalloc_track_caller is a special version of kmalloc that records the
264 * calling function of the routine calling it for slab leak tracking instead
265 * of just the calling function (confusing, eh?).
266 * It's useful when the call to kmalloc comes from a widely-used standard
267 * allocator where we care about the real place the memory allocation
268 * request comes from.
269 */
Christoph Lameter81819f02007-05-06 14:49:36 -0700270#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300271extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -0700272#define kmalloc_track_caller(size, flags) \
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300273 __kmalloc_track_caller(size, flags, _RET_IP_)
Christoph Lameter2e892f42006-12-13 00:34:23 -0800274#else
275#define kmalloc_track_caller(size, flags) \
276 __kmalloc(size, flags)
277#endif /* DEBUG_SLAB */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278
Manfred Spraul97e2bde2005-05-01 08:58:38 -0700279#ifdef CONFIG_NUMA
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800280/*
281 * kmalloc_node_track_caller is a special version of kmalloc_node that
282 * records the calling function of the routine calling it for slab leak
283 * tracking instead of just the calling function (confusing, eh?).
284 * It's useful when the call to kmalloc_node comes from a widely-used
285 * standard allocator where we care about the real place the memory
286 * allocation request comes from.
287 */
Christoph Lameter81819f02007-05-06 14:49:36 -0700288#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300289extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800290#define kmalloc_node_track_caller(size, flags, node) \
291 __kmalloc_node_track_caller(size, flags, node, \
Eduard - Gabriel Munteanuce71e272008-08-19 20:43:25 +0300292 _RET_IP_)
Christoph Lameter2e892f42006-12-13 00:34:23 -0800293#else
294#define kmalloc_node_track_caller(size, flags, node) \
295 __kmalloc_node(size, flags, node)
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800296#endif
Christoph Lameter2e892f42006-12-13 00:34:23 -0800297
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800298#else /* CONFIG_NUMA */
Christoph Lameter2e892f42006-12-13 00:34:23 -0800299
300#define kmalloc_node_track_caller(size, flags, node) \
301 kmalloc_track_caller(size, flags)
302
Pascal Terjandfcd3612008-11-25 15:08:19 +0100303#endif /* CONFIG_NUMA */
Christoph Hellwig8b98c162006-12-06 20:32:30 -0800304
Christoph Lameter81cda662007-07-17 04:03:29 -0700305/*
306 * Shortcuts
307 */
308static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
309{
310 return kmem_cache_alloc(k, flags | __GFP_ZERO);
311}
312
313/**
314 * kzalloc - allocate memory. The memory is set to zero.
315 * @size: how many bytes of memory are required.
316 * @flags: the type of memory to allocate (see kmalloc).
317 */
318static inline void *kzalloc(size_t size, gfp_t flags)
319{
320 return kmalloc(size, flags | __GFP_ZERO);
321}
322
Jeff Layton979b0fe2008-06-05 22:47:00 -0700323/**
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 */
329static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
330{
331 return kmalloc_node(size, flags | __GFP_ZERO, node);
332}
333
Pekka Enberg7e85ee02009-06-12 14:03:06 +0300334void __init kmem_cache_init_late(void);
335
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336#endif /* _LINUX_SLAB_H */