include/linux/slab.h

   1 /*
   2  * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
   3  *
   4  * (C) SGI 2006, Christoph Lameter <clameter@sgi.com>
   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 #ifdef __KERNEL__
  13
  14 #include <linux/gfp.h>
  15 #include <linux/types.h>
  16
  17 /*
  18  * Flags to pass to kmem_cache_create().
  19  * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
  20  */
  21 #define SLAB_DEBUG_FREE         0x00000100UL    /* DEBUG: Perform (expensive) checks on free */
  22 #define SLAB_RED_ZONE           0x00000400UL    /* DEBUG: Red zone objs in a cache */
  23 #define SLAB_POISON             0x00000800UL    /* DEBUG: Poison objects */
  24 #define SLAB_HWCACHE_ALIGN      0x00002000UL    /* Align objs on cache lines */
  25 #define SLAB_CACHE_DMA          0x00004000UL    /* Use GFP_DMA memory */
  26 #define SLAB_STORE_USER         0x00010000UL    /* DEBUG: Store the last owner for bug hunting */
  27 #define SLAB_RECLAIM_ACCOUNT    0x00020000UL    /* Objects are reclaimable */
  28 #define SLAB_PANIC              0x00040000UL    /* Panic if kmem_cache_create() fails */
  29 #define SLAB_DESTROY_BY_RCU     0x00080000UL    /* Defer freeing slabs to RCU */
  30 #define SLAB_MEM_SPREAD         0x00100000UL    /* Spread some memory over cpuset */
  31 #define SLAB_TRACE              0x00200000UL    /* Trace allocations and frees */
  32
  33 /*
  34  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
  35  *
  36  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
  37  *
  38  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
  39  * Both make kfree a no-op.
  40  */
  41 #define ZERO_SIZE_PTR ((void *)16)
  42
  43 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
  44                                 (unsigned long)ZERO_SIZE_PTR)
  45
  46 /*
  47  * struct kmem_cache related prototypes
  48  */
  49 void __init kmem_cache_init(void);
  50 int slab_is_available(void);
  51
  52 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
  53                         unsigned long,
  54                         void (*)(void *, struct kmem_cache *, unsigned long));
  55 void kmem_cache_destroy(struct kmem_cache *);
  56 int kmem_cache_shrink(struct kmem_cache *);
  57 void kmem_cache_free(struct kmem_cache *, void *);
  58 unsigned int kmem_cache_size(struct kmem_cache *);
  59 const char *kmem_cache_name(struct kmem_cache *);
  60 int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
  61
  62 /*
  63  * Please use this macro to create slab caches. Simply specify the
  64  * name of the structure and maybe some flags that are listed above.
  65  *
  66  * The alignment of the struct determines object alignment. If you
  67  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
  68  * then the objects will be properly aligned in SMP configurations.
  69  */
  70 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
  71                 sizeof(struct __struct), __alignof__(struct __struct),\
  72                 (__flags), NULL)
  73
  74 /*
  75  * The largest kmalloc size supported by the slab allocators is
  76  * 32 megabyte (2^25) or the maximum allocatable page order if that is
  77  * less than 32 MB.
  78  *
  79  * WARNING: Its not easy to increase this value since the allocators have
  80  * to do various tricks to work around compiler limitations in order to
  81  * ensure proper constant folding.
  82  */
  83 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
  84                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
  85
  86 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_HIGH)
  87 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
  88
  89 /*
  90  * Common kmalloc functions provided by all allocators
  91  */
  92 void * __must_check krealloc(const void *, size_t, gfp_t);
  93 void kfree(const void *);
  94 size_t ksize(const void *);
  95
  96 /*
  97  * Allocator specific definitions. These are mainly used to establish optimized
  98  * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
  99  * selecting the appropriate general cache at compile time.
 100  *
 101  * Allocators must define at least:
 102  *
 103  *      kmem_cache_alloc()
 104  *      __kmalloc()
 105  *      kmalloc()
 106  *
 107  * Those wishing to support NUMA must also define:
 108  *
 109  *      kmem_cache_alloc_node()
 110  *      kmalloc_node()
 111  *
 112  * See each allocator definition file for additional comments and
 113  * implementation notes.
 114  */
 115 #ifdef CONFIG_SLUB
 116 #include <linux/slub_def.h>
 117 #elif defined(CONFIG_SLOB)
 118 #include <linux/slob_def.h>
 119 #else
 120 #include <linux/slab_def.h>
 121 #endif
 122
 123 /**
 124  * kcalloc - allocate memory for an array. The memory is set to zero.
 125  * @n: number of elements.
 126  * @size: element size.
 127  * @flags: the type of memory to allocate.
 128  *
 129  * The @flags argument may be one of:
 130  *
 131  * %GFP_USER - Allocate memory on behalf of user.  May sleep.
 132  *
 133  * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
 134  *
 135  * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
 136  *   For example, use this inside interrupt handlers.
 137  *
 138  * %GFP_HIGHUSER - Allocate pages from high memory.
 139  *
 140  * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
 141  *
 142  * %GFP_NOFS - Do not make any fs calls while trying to get memory.
 143  *
 144  * %GFP_NOWAIT - Allocation will not sleep.
 145  *
 146  * %GFP_THISNODE - Allocate node-local memory only.
 147  *
 148  * %GFP_DMA - Allocation suitable for DMA.
 149  *   Should only be used for kmalloc() caches. Otherwise, use a
 150  *   slab created with SLAB_DMA.
 151  *
 152  * Also it is possible to set different flags by OR'ing
 153  * in one or more of the following additional @flags:
 154  *
 155  * %__GFP_COLD - Request cache-cold pages instead of
 156  *   trying to return cache-warm pages.
 157  *
 158  * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
 159  *
 160  * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
 161  *   (think twice before using).
 162  *
 163  * %__GFP_NORETRY - If memory is not immediately available,
 164  *   then give up at once.
 165  *
 166  * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
 167  *
 168  * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
 169  *
 170  * There are other flags available as well, but these are not intended
 171  * for general use, and so are not documented here. For a full list of
 172  * potential flags, always refer to linux/gfp.h.
 173  */
 174 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 175 {
 176         if (n != 0 && size > ULONG_MAX / n)
 177                 return NULL;
 178         return __kmalloc(n * size, flags | __GFP_ZERO);
 179 }
 180
 181 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
 182 /**
 183  * kmalloc_node - allocate memory from a specific node
 184  * @size: how many bytes of memory are required.
 185  * @flags: the type of memory to allocate (see kcalloc).
 186  * @node: node to allocate from.
 187  *
 188  * kmalloc() for non-local nodes, used to allocate from a specific node
 189  * if available. Equivalent to kmalloc() in the non-NUMA single-node
 190  * case.
 191  */
 192 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 193 {
 194         return kmalloc(size, flags);
 195 }
 196
 197 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 198 {
 199         return __kmalloc(size, flags);
 200 }
 201
 202 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 203
 204 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
 205                                         gfp_t flags, int node)
 206 {
 207         return kmem_cache_alloc(cachep, flags);
 208 }
 209 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
 210
 211 /*
 212  * kmalloc_track_caller is a special version of kmalloc that records the
 213  * calling function of the routine calling it for slab leak tracking instead
 214  * of just the calling function (confusing, eh?).
 215  * It's useful when the call to kmalloc comes from a widely-used standard
 216  * allocator where we care about the real place the memory allocation
 217  * request comes from.
 218  */
 219 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 220 extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
 221 #define kmalloc_track_caller(size, flags) \
 222         __kmalloc_track_caller(size, flags, __builtin_return_address(0))
 223 #else
 224 #define kmalloc_track_caller(size, flags) \
 225         __kmalloc(size, flags)
 226 #endif /* DEBUG_SLAB */
 227
 228 #ifdef CONFIG_NUMA
 229 /*
 230  * kmalloc_node_track_caller is a special version of kmalloc_node that
 231  * records the calling function of the routine calling it for slab leak
 232  * tracking instead of just the calling function (confusing, eh?).
 233  * It's useful when the call to kmalloc_node comes from a widely-used
 234  * standard allocator where we care about the real place the memory
 235  * allocation request comes from.
 236  */
 237 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 238 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
 239 #define kmalloc_node_track_caller(size, flags, node) \
 240         __kmalloc_node_track_caller(size, flags, node, \
 241                         __builtin_return_address(0))
 242 #else
 243 #define kmalloc_node_track_caller(size, flags, node) \
 244         __kmalloc_node(size, flags, node)
 245 #endif
 246
 247 #else /* CONFIG_NUMA */
 248
 249 #define kmalloc_node_track_caller(size, flags, node) \
 250         kmalloc_track_caller(size, flags)
 251
 252 #endif /* DEBUG_SLAB */
 253
 254 /*
 255  * Shortcuts
 256  */
 257 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
 258 {
 259         return kmem_cache_alloc(k, flags | __GFP_ZERO);
 260 }
 261
 262 /**
 263  * kzalloc - allocate memory. The memory is set to zero.
 264  * @size: how many bytes of memory are required.
 265  * @flags: the type of memory to allocate (see kmalloc).
 266  */
 267 static inline void *kzalloc(size_t size, gfp_t flags)
 268 {
 269         return kmalloc(size, flags | __GFP_ZERO);
 270 }
 271
 272 #endif  /* __KERNEL__ */
 273 #endif  /* _LINUX_SLAB_H */