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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
9#ifndef _LINUX_SLAB_H
10#define _LINUX_SLAB_H
11
12#include <linux/gfp.h>
13#include <linux/types.h>
14
15/*
16 * Flags to pass to kmem_cache_create().
17 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
18 */
19#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
20#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 */
23#define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
24#define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
25#define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
26/*
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 */
54#define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
55#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
56#define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
57
58/* 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
65#define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
66
67/* 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
73#ifdef CONFIG_FAILSLAB
74# define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */
75#else
76# define SLAB_FAILSLAB 0x00000000UL
77#endif
78
79/* 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 */
82/*
83 * 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
92#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
93 (unsigned long)ZERO_SIZE_PTR)
94
95/*
96 * struct kmem_cache related prototypes
97 */
98void __init kmem_cache_init(void);
99int slab_is_available(void);
100
101struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
102 unsigned long,
103 void (*)(void *));
104void kmem_cache_destroy(struct kmem_cache *);
105int kmem_cache_shrink(struct kmem_cache *);
106void kmem_cache_free(struct kmem_cache *, void *);
107unsigned int kmem_cache_size(struct kmem_cache *);
108const char *kmem_cache_name(struct kmem_cache *);
109int kern_ptr_validate(const void *ptr, unsigned long size);
110int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
111
112/*
113 * Please use this macro to create slab caches. Simply specify the
114 * name of the structure and maybe some flags that are listed above.
115 *
116 * The alignment of the struct determines object alignment. If you
117 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
118 * then the objects will be properly aligned in SMP configurations.
119 */
120#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
121 sizeof(struct __struct), __alignof__(struct __struct),\
122 (__flags), NULL)
123
124/*
125 * The largest kmalloc size supported by the slab allocators is
126 * 32 megabyte (2^25) or the maximum allocatable page order if that is
127 * less than 32 MB.
128 *
129 * WARNING: Its not easy to increase this value since the allocators have
130 * to do various tricks to work around compiler limitations in order to
131 * ensure proper constant folding.
132 */
133#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
134 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
135
136#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
137#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
138
139/*
140 * Common kmalloc functions provided by all allocators
141 */
142void * __must_check __krealloc(const void *, size_t, gfp_t);
143void * __must_check krealloc(const void *, size_t, gfp_t);
144void kfree(const void *);
145void kzfree(const void *);
146size_t ksize(const void *);
147
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/**
176 * kcalloc - allocate memory for an array. The memory is set to zero.
177 * @n: number of elements.
178 * @size: element size.
179 * @flags: the type of memory to allocate.
180 *
181 * The @flags argument may be one of:
182 *
183 * %GFP_USER - Allocate memory on behalf of user. May sleep.
184 *
185 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
186 *
187 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
188 * For example, use this inside interrupt handlers.
189 *
190 * %GFP_HIGHUSER - Allocate pages from high memory.
191 *
192 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
193 *
194 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
195 *
196 * %GFP_NOWAIT - Allocation will not sleep.
197 *
198 * %GFP_THISNODE - Allocate node-local memory only.
199 *
200 * %GFP_DMA - Allocation suitable for DMA.
201 * Should only be used for kmalloc() caches. Otherwise, use a
202 * slab created with SLAB_DMA.
203 *
204 * Also it is possible to set different flags by OR'ing
205 * in one or more of the following additional @flags:
206 *
207 * %__GFP_COLD - Request cache-cold pages instead of
208 * trying to return cache-warm pages.
209 *
210 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
211 *
212 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
213 * (think twice before using).
214 *
215 * %__GFP_NORETRY - If memory is not immediately available,
216 * then give up at once.
217 *
218 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
219 *
220 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
221 *
222 * There are other flags available as well, but these are not intended
223 * for general use, and so are not documented here. For a full list of
224 * potential flags, always refer to linux/gfp.h.
225 */
226static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
227{
228 if (size != 0 && n > ULONG_MAX / size)
229 return NULL;
230 return __kmalloc(n * size, flags | __GFP_ZERO);
231}
232
233#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
234/**
235 * kmalloc_node - allocate memory from a specific node
236 * @size: how many bytes of memory are required.
237 * @flags: the type of memory to allocate (see kcalloc).
238 * @node: node to allocate from.
239 *
240 * kmalloc() for non-local nodes, used to allocate from a specific node
241 * if available. Equivalent to kmalloc() in the non-NUMA single-node
242 * case.
243 */
244static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
245{
246 return kmalloc(size, flags);
247}
248
249static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
250{
251 return __kmalloc(size, flags);
252}
253
254void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
255
256static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
257 gfp_t flags, int node)
258{
259 return kmem_cache_alloc(cachep, flags);
260}
261#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
262
263/*
264 * kmalloc_track_caller is a special version of kmalloc that records the
265 * calling function of the routine calling it for slab leak tracking instead
266 * of just the calling function (confusing, eh?).
267 * It's useful when the call to kmalloc comes from a widely-used standard
268 * allocator where we care about the real place the memory allocation
269 * request comes from.
270 */
271#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
272 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
273extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
274#define kmalloc_track_caller(size, flags) \
275 __kmalloc_track_caller(size, flags, _RET_IP_)
276#else
277#define kmalloc_track_caller(size, flags) \
278 __kmalloc(size, flags)
279#endif /* DEBUG_SLAB */
280
281#ifdef CONFIG_NUMA
282/*
283 * kmalloc_node_track_caller is a special version of kmalloc_node that
284 * records the calling function of the routine calling it for slab leak
285 * tracking instead of just the calling function (confusing, eh?).
286 * It's useful when the call to kmalloc_node comes from a widely-used
287 * standard allocator where we care about the real place the memory
288 * allocation request comes from.
289 */
290#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
291 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
292extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
293#define kmalloc_node_track_caller(size, flags, node) \
294 __kmalloc_node_track_caller(size, flags, node, \
295 _RET_IP_)
296#else
297#define kmalloc_node_track_caller(size, flags, node) \
298 __kmalloc_node(size, flags, node)
299#endif
300
301#else /* CONFIG_NUMA */
302
303#define kmalloc_node_track_caller(size, flags, node) \
304 kmalloc_track_caller(size, flags)
305
306#endif /* CONFIG_NUMA */
307
308/*
309 * Shortcuts
310 */
311static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
312{
313 return kmem_cache_alloc(k, flags | __GFP_ZERO);
314}
315
316/**
317 * kzalloc - allocate memory. The memory is set to zero.
318 * @size: how many bytes of memory are required.
319 * @flags: the type of memory to allocate (see kmalloc).
320 */
321static inline void *kzalloc(size_t size, gfp_t flags)
322{
323 return kmalloc(size, flags | __GFP_ZERO);
324}
325
326/**
327 * kzalloc_node - allocate zeroed memory from a particular memory node.
328 * @size: how many bytes of memory are required.
329 * @flags: the type of memory to allocate (see kmalloc).
330 * @node: memory node from which to allocate
331 */
332static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
333{
334 return kmalloc_node(size, flags | __GFP_ZERO, node);
335}
336
337void __init kmem_cache_init_late(void);
338
339#endif /* _LINUX_SLAB_H */