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 */
98 void __init kmem_cache_init(void);
99 int slab_is_available(void);
100
101 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
102 unsigned long,
103 void (*)(void *));
104 void kmem_cache_destroy(struct kmem_cache *);
105 int kmem_cache_shrink(struct kmem_cache *);
106 void kmem_cache_free(struct kmem_cache *, void *);
107 unsigned int kmem_cache_size(struct kmem_cache *);
108
109 /*
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),\
119 (__flags), NULL)
120
121 /*
122 * 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 */
130 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
131 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
132
133 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
134 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
135
136 /*
137 * Common kmalloc functions provided by all allocators
138 */
139 void * __must_check __krealloc(const void *, size_t, gfp_t);
140 void * __must_check krealloc(const void *, size_t, gfp_t);
141 void kfree(const void *);
142 void kzfree(const void *);
143 size_t ksize(const void *);
144
145 /*
146 * Allocator specific definitions. These are mainly used to establish optimized
147 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
148 * selecting the appropriate general cache at compile time.
149 *
150 * Allocators must define at least:
151 *
152 * kmem_cache_alloc()
153 * __kmalloc()
154 * kmalloc()
155 *
156 * Those wishing to support NUMA must also define:
157 *
158 * kmem_cache_alloc_node()
159 * kmalloc_node()
160 *
161 * See each allocator definition file for additional comments and
162 * implementation notes.
163 */
164 #ifdef CONFIG_SLUB
165 #include <linux/slub_def.h>
166 #elif defined(CONFIG_SLOB)
167 #include <linux/slob_def.h>
168 #else
169 #include <linux/slab_def.h>
170 #endif
171
172 /**
173 * kcalloc - allocate memory for an array. The memory is set to zero.
174 * @n: number of elements.
175 * @size: element size.
176 * @flags: the type of memory to allocate.
177 *
178 * The @flags argument may be one of:
179 *
180 * %GFP_USER - Allocate memory on behalf of user. May sleep.
181 *
182 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
183 *
184 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
185 * For example, use this inside interrupt handlers.
186 *
187 * %GFP_HIGHUSER - Allocate pages from high memory.
188 *
189 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
190 *
191 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
192 *
193 * %GFP_NOWAIT - Allocation will not sleep.
194 *
195 * %GFP_THISNODE - Allocate node-local memory only.
196 *
197 * %GFP_DMA - Allocation suitable for DMA.
198 * Should only be used for kmalloc() caches. Otherwise, use a
199 * slab created with SLAB_DMA.
200 *
201 * Also it is possible to set different flags by OR'ing
202 * in one or more of the following additional @flags:
203 *
204 * %__GFP_COLD - Request cache-cold pages instead of
205 * trying to return cache-warm pages.
206 *
207 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
208 *
209 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
210 * (think twice before using).
211 *
212 * %__GFP_NORETRY - If memory is not immediately available,
213 * then give up at once.
214 *
215 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
216 *
217 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
218 *
219 * There are other flags available as well, but these are not intended
220 * for general use, and so are not documented here. For a full list of
221 * potential flags, always refer to linux/gfp.h.
222 */
kcalloc(size_t n,size_t size,gfp_t flags)223 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
224 {
225 if (size != 0 && n > ULONG_MAX / size)
226 return NULL;
227 return __kmalloc(n * size, flags | __GFP_ZERO);
228 }
229
230 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
231 /**
232 * kmalloc_node - allocate memory from a specific node
233 * @size: how many bytes of memory are required.
234 * @flags: the type of memory to allocate (see kcalloc).
235 * @node: node to allocate from.
236 *
237 * kmalloc() for non-local nodes, used to allocate from a specific node
238 * if available. Equivalent to kmalloc() in the non-NUMA single-node
239 * case.
240 */
kmalloc_node(size_t size,gfp_t flags,int node)241 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
242 {
243 return kmalloc(size, flags);
244 }
245
__kmalloc_node(size_t size,gfp_t flags,int node)246 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
247 {
248 return __kmalloc(size, flags);
249 }
250
251 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
252
kmem_cache_alloc_node(struct kmem_cache * cachep,gfp_t flags,int node)253 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
254 gfp_t flags, int node)
255 {
256 return kmem_cache_alloc(cachep, flags);
257 }
258 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
259
260 /*
261 * kmalloc_track_caller is a special version of kmalloc that records the
262 * calling function of the routine calling it for slab leak tracking instead
263 * of just the calling function (confusing, eh?).
264 * It's useful when the call to kmalloc comes from a widely-used standard
265 * allocator where we care about the real place the memory allocation
266 * request comes from.
267 */
268 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
269 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
270 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
271 #define kmalloc_track_caller(size, flags) \
272 __kmalloc_track_caller(size, flags, _RET_IP_)
273 #else
274 #define kmalloc_track_caller(size, flags) \
275 __kmalloc(size, flags)
276 #endif /* DEBUG_SLAB */
277
278 #ifdef CONFIG_NUMA
279 /*
280 * kmalloc_node_track_caller is a special version of kmalloc_node that
281 * records the calling function of the routine calling it for slab leak
282 * tracking instead of just the calling function (confusing, eh?).
283 * It's useful when the call to kmalloc_node comes from a widely-used
284 * standard allocator where we care about the real place the memory
285 * allocation request comes from.
286 */
287 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
288 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
289 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
290 #define kmalloc_node_track_caller(size, flags, node) \
291 __kmalloc_node_track_caller(size, flags, node, \
292 _RET_IP_)
293 #else
294 #define kmalloc_node_track_caller(size, flags, node) \
295 __kmalloc_node(size, flags, node)
296 #endif
297
298 #else /* CONFIG_NUMA */
299
300 #define kmalloc_node_track_caller(size, flags, node) \
301 kmalloc_track_caller(size, flags)
302
303 #endif /* CONFIG_NUMA */
304
305 /*
306 * Shortcuts
307 */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)308 static 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 */
kzalloc(size_t size,gfp_t flags)318 static inline void *kzalloc(size_t size, gfp_t flags)
319 {
320 return kmalloc(size, flags | __GFP_ZERO);
321 }
322
323 /**
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 */
kzalloc_node(size_t size,gfp_t flags,int node)329 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
330 {
331 return kmalloc_node(size, flags | __GFP_ZERO, node);
332 }
333
334 void __init kmem_cache_init_late(void);
335
336 #endif /* _LINUX_SLAB_H */
337