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 /* The following flags affect the page allocator grouping pages by mobility */
66 #define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
67 #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
68 /*
69 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
70 *
71 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
72 *
73 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
74 * Both make kfree a no-op.
75 */
76 #define ZERO_SIZE_PTR ((void *)16)
77
78 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
79 (unsigned long)ZERO_SIZE_PTR)
80
81 /*
82 * struct kmem_cache related prototypes
83 */
84 void __init kmem_cache_init(void);
85 int slab_is_available(void);
86
87 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
88 unsigned long,
89 void (*)(void *));
90 void kmem_cache_destroy(struct kmem_cache *);
91 int kmem_cache_shrink(struct kmem_cache *);
92 void kmem_cache_free(struct kmem_cache *, void *);
93 unsigned int kmem_cache_size(struct kmem_cache *);
94 const char *kmem_cache_name(struct kmem_cache *);
95 int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
96
97 /*
98 * Please use this macro to create slab caches. Simply specify the
99 * name of the structure and maybe some flags that are listed above.
100 *
101 * The alignment of the struct determines object alignment. If you
102 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
103 * then the objects will be properly aligned in SMP configurations.
104 */
105 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
106 sizeof(struct __struct), __alignof__(struct __struct),\
107 (__flags), NULL)
108
109 /*
110 * The largest kmalloc size supported by the slab allocators is
111 * 32 megabyte (2^25) or the maximum allocatable page order if that is
112 * less than 32 MB.
113 *
114 * WARNING: Its not easy to increase this value since the allocators have
115 * to do various tricks to work around compiler limitations in order to
116 * ensure proper constant folding.
117 */
118 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
119 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
120
121 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
122 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
123
124 /*
125 * Common kmalloc functions provided by all allocators
126 */
127 void * __must_check __krealloc(const void *, size_t, gfp_t);
128 void * __must_check krealloc(const void *, size_t, gfp_t);
129 void kfree(const void *);
130 void kzfree(const void *);
131 size_t ksize(const void *);
132
133 /*
134 * Allocator specific definitions. These are mainly used to establish optimized
135 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
136 * selecting the appropriate general cache at compile time.
137 *
138 * Allocators must define at least:
139 *
140 * kmem_cache_alloc()
141 * __kmalloc()
142 * kmalloc()
143 *
144 * Those wishing to support NUMA must also define:
145 *
146 * kmem_cache_alloc_node()
147 * kmalloc_node()
148 *
149 * See each allocator definition file for additional comments and
150 * implementation notes.
151 */
152 #ifdef CONFIG_SLUB
153 #include <linux/slub_def.h>
154 #elif defined(CONFIG_SLOB)
155 #include <linux/slob_def.h>
156 #else
157 #include <linux/slab_def.h>
158 #endif
159
160 /**
161 * kcalloc - allocate memory for an array. The memory is set to zero.
162 * @n: number of elements.
163 * @size: element size.
164 * @flags: the type of memory to allocate.
165 *
166 * The @flags argument may be one of:
167 *
168 * %GFP_USER - Allocate memory on behalf of user. May sleep.
169 *
170 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
171 *
172 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
173 * For example, use this inside interrupt handlers.
174 *
175 * %GFP_HIGHUSER - Allocate pages from high memory.
176 *
177 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
178 *
179 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
180 *
181 * %GFP_NOWAIT - Allocation will not sleep.
182 *
183 * %GFP_THISNODE - Allocate node-local memory only.
184 *
185 * %GFP_DMA - Allocation suitable for DMA.
186 * Should only be used for kmalloc() caches. Otherwise, use a
187 * slab created with SLAB_DMA.
188 *
189 * Also it is possible to set different flags by OR'ing
190 * in one or more of the following additional @flags:
191 *
192 * %__GFP_COLD - Request cache-cold pages instead of
193 * trying to return cache-warm pages.
194 *
195 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
196 *
197 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
198 * (think twice before using).
199 *
200 * %__GFP_NORETRY - If memory is not immediately available,
201 * then give up at once.
202 *
203 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
204 *
205 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
206 *
207 * There are other flags available as well, but these are not intended
208 * for general use, and so are not documented here. For a full list of
209 * potential flags, always refer to linux/gfp.h.
210 */
kcalloc(size_t n,size_t size,gfp_t flags)211 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
212 {
213 if (size != 0 && n > ULONG_MAX / size)
214 return NULL;
215 return __kmalloc(n * size, flags | __GFP_ZERO);
216 }
217
218 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
219 /**
220 * kmalloc_node - allocate memory from a specific node
221 * @size: how many bytes of memory are required.
222 * @flags: the type of memory to allocate (see kcalloc).
223 * @node: node to allocate from.
224 *
225 * kmalloc() for non-local nodes, used to allocate from a specific node
226 * if available. Equivalent to kmalloc() in the non-NUMA single-node
227 * case.
228 */
kmalloc_node(size_t size,gfp_t flags,int node)229 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
230 {
231 return kmalloc(size, flags);
232 }
233
__kmalloc_node(size_t size,gfp_t flags,int node)234 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
235 {
236 return __kmalloc(size, flags);
237 }
238
239 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
240
kmem_cache_alloc_node(struct kmem_cache * cachep,gfp_t flags,int node)241 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
242 gfp_t flags, int node)
243 {
244 return kmem_cache_alloc(cachep, flags);
245 }
246 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
247
248 /*
249 * kmalloc_track_caller is a special version of kmalloc that records the
250 * calling function of the routine calling it for slab leak tracking instead
251 * of just the calling function (confusing, eh?).
252 * It's useful when the call to kmalloc comes from a widely-used standard
253 * allocator where we care about the real place the memory allocation
254 * request comes from.
255 */
256 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
257 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
258 #define kmalloc_track_caller(size, flags) \
259 __kmalloc_track_caller(size, flags, _RET_IP_)
260 #else
261 #define kmalloc_track_caller(size, flags) \
262 __kmalloc(size, flags)
263 #endif /* DEBUG_SLAB */
264
265 #ifdef CONFIG_NUMA
266 /*
267 * kmalloc_node_track_caller is a special version of kmalloc_node that
268 * records the calling function of the routine calling it for slab leak
269 * tracking instead of just the calling function (confusing, eh?).
270 * It's useful when the call to kmalloc_node comes from a widely-used
271 * standard allocator where we care about the real place the memory
272 * allocation request comes from.
273 */
274 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
275 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
276 #define kmalloc_node_track_caller(size, flags, node) \
277 __kmalloc_node_track_caller(size, flags, node, \
278 _RET_IP_)
279 #else
280 #define kmalloc_node_track_caller(size, flags, node) \
281 __kmalloc_node(size, flags, node)
282 #endif
283
284 #else /* CONFIG_NUMA */
285
286 #define kmalloc_node_track_caller(size, flags, node) \
287 kmalloc_track_caller(size, flags)
288
289 #endif /* CONFIG_NUMA */
290
291 /*
292 * Shortcuts
293 */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)294 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
295 {
296 return kmem_cache_alloc(k, flags | __GFP_ZERO);
297 }
298
299 /**
300 * kzalloc - allocate memory. The memory is set to zero.
301 * @size: how many bytes of memory are required.
302 * @flags: the type of memory to allocate (see kmalloc).
303 */
kzalloc(size_t size,gfp_t flags)304 static inline void *kzalloc(size_t size, gfp_t flags)
305 {
306 return kmalloc(size, flags | __GFP_ZERO);
307 }
308
309 /**
310 * kzalloc_node - allocate zeroed memory from a particular memory node.
311 * @size: how many bytes of memory are required.
312 * @flags: the type of memory to allocate (see kmalloc).
313 * @node: memory node from which to allocate
314 */
kzalloc_node(size_t size,gfp_t flags,int node)315 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
316 {
317 return kmalloc_node(size, flags | __GFP_ZERO, node);
318 }
319
320 #endif /* _LINUX_SLAB_H */
321