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 * 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 */
141 #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
147 /*
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 */
152 #ifndef ARCH_SLAB_MINALIGN
153 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
154 #endif
155
156 /*
157 * Common kmalloc functions provided by all allocators
158 */
159 void * __must_check __krealloc(const void *, size_t, gfp_t);
160 void * __must_check krealloc(const void *, size_t, gfp_t);
161 void kfree(const void *);
162 void kzfree(const void *);
163 size_t ksize(const void *);
164
165 /*
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
192 /**
193 * kmalloc_array - allocate memory for an array.
194 * @n: number of elements.
195 * @size: element size.
196 * @flags: the type of memory to allocate.
197 *
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 *
204 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
205 * 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 *
213 * %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 *
221 * 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 *
227 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
228 *
229 * %__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.
238 *
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.
242 */
kmalloc_array(size_t n,size_t size,gfp_t flags)243 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
244 {
245 if (size != 0 && n > ULONG_MAX / size)
246 return NULL;
247 return __kmalloc(n * size, flags);
248 }
249
250 /**
251 * kcalloc - allocate memory for an array. The memory is set to zero.
252 * @n: number of elements.
253 * @size: element size.
254 * @flags: the type of memory to allocate (see kmalloc).
255 */
kcalloc(size_t n,size_t size,gfp_t flags)256 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
257 {
258 return kmalloc_array(n, size, flags | __GFP_ZERO);
259 }
260
261 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
262 /**
263 * kmalloc_node - allocate memory from a specific node
264 * @size: how many bytes of memory are required.
265 * @flags: the type of memory to allocate (see kcalloc).
266 * @node: node to allocate from.
267 *
268 * kmalloc() for non-local nodes, used to allocate from a specific node
269 * if available. Equivalent to kmalloc() in the non-NUMA single-node
270 * case.
271 */
kmalloc_node(size_t size,gfp_t flags,int node)272 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
273 {
274 return kmalloc(size, flags);
275 }
276
__kmalloc_node(size_t size,gfp_t flags,int node)277 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
278 {
279 return __kmalloc(size, flags);
280 }
281
282 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
283
kmem_cache_alloc_node(struct kmem_cache * cachep,gfp_t flags,int node)284 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
285 gfp_t flags, int node)
286 {
287 return kmem_cache_alloc(cachep, flags);
288 }
289 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
290
291 /*
292 * kmalloc_track_caller is a special version of kmalloc that records the
293 * calling function of the routine calling it for slab leak tracking instead
294 * of just the calling function (confusing, eh?).
295 * It's useful when the call to kmalloc comes from a widely-used standard
296 * allocator where we care about the real place the memory allocation
297 * request comes from.
298 */
299 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
300 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
301 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
302 #define kmalloc_track_caller(size, flags) \
303 __kmalloc_track_caller(size, flags, _RET_IP_)
304 #else
305 #define kmalloc_track_caller(size, flags) \
306 __kmalloc(size, flags)
307 #endif /* DEBUG_SLAB */
308
309 #ifdef CONFIG_NUMA
310 /*
311 * kmalloc_node_track_caller is a special version of kmalloc_node that
312 * records the calling function of the routine calling it for slab leak
313 * tracking instead of just the calling function (confusing, eh?).
314 * It's useful when the call to kmalloc_node comes from a widely-used
315 * standard allocator where we care about the real place the memory
316 * allocation request comes from.
317 */
318 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
319 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
320 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
321 #define kmalloc_node_track_caller(size, flags, node) \
322 __kmalloc_node_track_caller(size, flags, node, \
323 _RET_IP_)
324 #else
325 #define kmalloc_node_track_caller(size, flags, node) \
326 __kmalloc_node(size, flags, node)
327 #endif
328
329 #else /* CONFIG_NUMA */
330
331 #define kmalloc_node_track_caller(size, flags, node) \
332 kmalloc_track_caller(size, flags)
333
334 #endif /* CONFIG_NUMA */
335
336 /*
337 * Shortcuts
338 */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)339 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
340 {
341 return kmem_cache_alloc(k, flags | __GFP_ZERO);
342 }
343
344 /**
345 * kzalloc - allocate memory. The memory is set to zero.
346 * @size: how many bytes of memory are required.
347 * @flags: the type of memory to allocate (see kmalloc).
348 */
kzalloc(size_t size,gfp_t flags)349 static inline void *kzalloc(size_t size, gfp_t flags)
350 {
351 return kmalloc(size, flags | __GFP_ZERO);
352 }
353
354 /**
355 * kzalloc_node - allocate zeroed memory from a particular memory node.
356 * @size: how many bytes of memory are required.
357 * @flags: the type of memory to allocate (see kmalloc).
358 * @node: memory node from which to allocate
359 */
kzalloc_node(size_t size,gfp_t flags,int node)360 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
361 {
362 return kmalloc_node(size, flags | __GFP_ZERO, node);
363 }
364
365 void __init kmem_cache_init_late(void);
366
367 #endif /* _LINUX_SLAB_H */
368