Line data Source code
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 :
74 : /* The following flags affect the page allocator grouping pages by mobility */
75 : #define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
76 : #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
77 : /*
78 : * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
79 : *
80 : * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
81 : *
82 : * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
83 : * Both make kfree a no-op.
84 : */
85 : #define ZERO_SIZE_PTR ((void *)16)
86 :
87 : #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
88 : (unsigned long)ZERO_SIZE_PTR)
89 :
90 : /*
91 : * struct kmem_cache related prototypes
92 : */
93 : void __init kmem_cache_init(void);
94 : int slab_is_available(void);
95 :
96 : struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
97 : unsigned long,
98 : void (*)(void *));
99 : void kmem_cache_destroy(struct kmem_cache *);
100 : int kmem_cache_shrink(struct kmem_cache *);
101 : void kmem_cache_free(struct kmem_cache *, void *);
102 : unsigned int kmem_cache_size(struct kmem_cache *);
103 : const char *kmem_cache_name(struct kmem_cache *);
104 : int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
105 :
106 : /*
107 : * Please use this macro to create slab caches. Simply specify the
108 : * name of the structure and maybe some flags that are listed above.
109 : *
110 : * The alignment of the struct determines object alignment. If you
111 : * f.e. add ____cacheline_aligned_in_smp to the struct declaration
112 : * then the objects will be properly aligned in SMP configurations.
113 : */
114 : #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
115 : sizeof(struct __struct), __alignof__(struct __struct),\
116 : (__flags), NULL)
117 :
118 : /*
119 : * The largest kmalloc size supported by the slab allocators is
120 : * 32 megabyte (2^25) or the maximum allocatable page order if that is
121 : * less than 32 MB.
122 : *
123 : * WARNING: Its not easy to increase this value since the allocators have
124 : * to do various tricks to work around compiler limitations in order to
125 : * ensure proper constant folding.
126 : */
127 : #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
128 : (MAX_ORDER + PAGE_SHIFT - 1) : 25)
129 :
130 : #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
131 : #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
132 :
133 : /*
134 : * Common kmalloc functions provided by all allocators
135 : */
136 : void * __must_check __krealloc(const void *, size_t, gfp_t);
137 : void * __must_check krealloc(const void *, size_t, gfp_t);
138 : void kfree(const void *);
139 : void kzfree(const void *);
140 : size_t ksize(const void *);
141 :
142 : /*
143 : * Allocator specific definitions. These are mainly used to establish optimized
144 : * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
145 : * selecting the appropriate general cache at compile time.
146 : *
147 : * Allocators must define at least:
148 : *
149 : * kmem_cache_alloc()
150 : * __kmalloc()
151 : * kmalloc()
152 : *
153 : * Those wishing to support NUMA must also define:
154 : *
155 : * kmem_cache_alloc_node()
156 : * kmalloc_node()
157 : *
158 : * See each allocator definition file for additional comments and
159 : * implementation notes.
160 : */
161 : #ifdef CONFIG_SLUB
162 : #include <linux/slub_def.h>
163 : #elif defined(CONFIG_SLOB)
164 : #include <linux/slob_def.h>
165 : #else
166 : #include <linux/slab_def.h>
167 : #endif
168 :
169 : /**
170 : * kcalloc - allocate memory for an array. The memory is set to zero.
171 : * @n: number of elements.
172 : * @size: element size.
173 : * @flags: the type of memory to allocate.
174 : *
175 : * The @flags argument may be one of:
176 : *
177 : * %GFP_USER - Allocate memory on behalf of user. May sleep.
178 : *
179 : * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
180 : *
181 : * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
182 : * For example, use this inside interrupt handlers.
183 : *
184 : * %GFP_HIGHUSER - Allocate pages from high memory.
185 : *
186 : * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
187 : *
188 : * %GFP_NOFS - Do not make any fs calls while trying to get memory.
189 : *
190 : * %GFP_NOWAIT - Allocation will not sleep.
191 : *
192 : * %GFP_THISNODE - Allocate node-local memory only.
193 : *
194 : * %GFP_DMA - Allocation suitable for DMA.
195 : * Should only be used for kmalloc() caches. Otherwise, use a
196 : * slab created with SLAB_DMA.
197 : *
198 : * Also it is possible to set different flags by OR'ing
199 : * in one or more of the following additional @flags:
200 : *
201 : * %__GFP_COLD - Request cache-cold pages instead of
202 : * trying to return cache-warm pages.
203 : *
204 : * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
205 : *
206 : * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
207 : * (think twice before using).
208 : *
209 : * %__GFP_NORETRY - If memory is not immediately available,
210 : * then give up at once.
211 : *
212 : * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
213 : *
214 : * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
215 : *
216 : * There are other flags available as well, but these are not intended
217 : * for general use, and so are not documented here. For a full list of
218 : * potential flags, always refer to linux/gfp.h.
219 : */
220 : static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
221 : {
222 : if (size != 0 && n > ULONG_MAX / size)
223 : return NULL;
224 : return __kmalloc(n * size, flags | __GFP_ZERO);
225 : }
226 :
227 : #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
228 : /**
229 : * kmalloc_node - allocate memory from a specific node
230 : * @size: how many bytes of memory are required.
231 : * @flags: the type of memory to allocate (see kcalloc).
232 : * @node: node to allocate from.
233 : *
234 : * kmalloc() for non-local nodes, used to allocate from a specific node
235 : * if available. Equivalent to kmalloc() in the non-NUMA single-node
236 : * case.
237 : */
238 : static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
239 : {
240 : return kmalloc(size, flags);
241 : }
242 :
243 : static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
244 : {
245 : return __kmalloc(size, flags);
246 : }
247 :
248 : void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
249 :
250 : static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
251 : gfp_t flags, int node)
252 : {
253 : return kmem_cache_alloc(cachep, flags);
254 : }
255 : #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
256 :
257 : /*
258 : * kmalloc_track_caller is a special version of kmalloc that records the
259 : * calling function of the routine calling it for slab leak tracking instead
260 : * of just the calling function (confusing, eh?).
261 : * It's useful when the call to kmalloc comes from a widely-used standard
262 : * allocator where we care about the real place the memory allocation
263 : * request comes from.
264 : */
265 : #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
266 : extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
267 : #define kmalloc_track_caller(size, flags) \
268 : __kmalloc_track_caller(size, flags, _RET_IP_)
269 : #else
270 : #define kmalloc_track_caller(size, flags) \
271 : __kmalloc(size, flags)
272 : #endif /* DEBUG_SLAB */
273 :
274 : #ifdef CONFIG_NUMA
275 : /*
276 : * kmalloc_node_track_caller is a special version of kmalloc_node that
277 : * records the calling function of the routine calling it for slab leak
278 : * tracking instead of just the calling function (confusing, eh?).
279 : * It's useful when the call to kmalloc_node comes from a widely-used
280 : * standard allocator where we care about the real place the memory
281 : * allocation request comes from.
282 : */
283 : #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
284 : extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
285 : #define kmalloc_node_track_caller(size, flags, node) \
286 : __kmalloc_node_track_caller(size, flags, node, \
287 : _RET_IP_)
288 : #else
289 : #define kmalloc_node_track_caller(size, flags, node) \
290 : __kmalloc_node(size, flags, node)
291 : #endif
292 :
293 : #else /* CONFIG_NUMA */
294 :
295 : #define kmalloc_node_track_caller(size, flags, node) \
296 : kmalloc_track_caller(size, flags)
297 :
298 : #endif /* CONFIG_NUMA */
299 :
300 : /*
301 : * Shortcuts
302 : */
303 : static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
304 : {
305 0 : return kmem_cache_alloc(k, flags | __GFP_ZERO);
306 : }
307 :
308 : /**
309 : * kzalloc - allocate memory. The memory is set to zero.
310 : * @size: how many bytes of memory are required.
311 : * @flags: the type of memory to allocate (see kmalloc).
312 : */
313 : static inline void *kzalloc(size_t size, gfp_t flags)
314 : {
315 : return kmalloc(size, flags | __GFP_ZERO);
316 : }
317 :
318 : /**
319 : * kzalloc_node - allocate zeroed memory from a particular memory node.
320 : * @size: how many bytes of memory are required.
321 : * @flags: the type of memory to allocate (see kmalloc).
322 : * @node: memory node from which to allocate
323 : */
324 : static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
325 : {
326 : return kmalloc_node(size, flags | __GFP_ZERO, node);
327 : }
328 :
329 : void __init kmem_cache_init_late(void);
330 :
331 : #endif /* _LINUX_SLAB_H */
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