1 /* 2 * Written by Mark Hemment, 1996 ([email protected]). 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 */ 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 */ 229 static inline void *kmalloc_node(size_t size, gfp_t flags, int node) 230 { 231 return kmalloc(size, flags); 232 } 233 234 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); 240 241 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 */ 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 */ 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 */ 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