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 (*)(void *, struct kmem_cache *, unsigned long));
  56 void kmem_cache_destroy(struct kmem_cache *);
  57 int kmem_cache_shrink(struct kmem_cache *);
  58 void *kmem_cache_zalloc(struct kmem_cache *, gfp_t);
  59 void kmem_cache_free(struct kmem_cache *, void *);
  60 unsigned int kmem_cache_size(struct kmem_cache *);
  61 const char *kmem_cache_name(struct kmem_cache *);
  62 int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
  63
  64 /*
  65  * Please use this macro to create slab caches. Simply specify the
  66  * name of the structure and maybe some flags that are listed above.
  67  *
  68  * The alignment of the struct determines object alignment. If you
  69  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
  70  * then the objects will be properly aligned in SMP configurations.
  71  */
  72 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
  73                 sizeof(struct __struct), __alignof__(struct __struct),\
  74                 (__flags), NULL, NULL)
  75
  76 /*
  77  * The largest kmalloc size supported by the slab allocators is
  78  * 32 megabyte (2^25) or the maximum allocatable page order if that is
  79  * less than 32 MB.
  80  *
  81  * WARNING: Its not easy to increase this value since the allocators have
  82  * to do various tricks to work around compiler limitations in order to
  83  * ensure proper constant folding.
  84  */
  85 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
  86                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
  87
  88 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_HIGH)
  89 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
  90
  91 /*
  92  * Common kmalloc functions provided by all allocators
  93  */
  94 void *__kzalloc(size_t, gfp_t);
  95 void * __must_check krealloc(const void *, size_t, gfp_t);
  96 void kfree(const void *);
  97 size_t ksize(const void *);
  98
  99 /**
 100  * kcalloc - allocate memory for an array. The memory is set to zero.
 101  * @n: number of elements.
 102  * @size: element size.
 103  * @flags: the type of memory to allocate.
 104  *
 105  * The @flags argument may be one of:
 106  *
 107  * %GFP_USER - Allocate memory on behalf of user.  May sleep.
 108  *
 109  * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
 110  *
 111  * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
 112  *   For example, use this inside interrupt handlers.
 113  *
 114  * %GFP_HIGHUSER - Allocate pages from high memory.
 115  *
 116  * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
 117  *
 118  * %GFP_NOFS - Do not make any fs calls while trying to get memory.
 119  *
 120  * %GFP_NOWAIT - Allocation will not sleep.
 121  *
 122  * %GFP_THISNODE - Allocate node-local memory only.
 123  *
 124  * %GFP_DMA - Allocation suitable for DMA.
 125  *   Should only be used for kmalloc() caches. Otherwise, use a
 126  *   slab created with SLAB_DMA.
 127  *
 128  * Also it is possible to set different flags by OR'ing
 129  * in one or more of the following additional @flags:
 130  *
 131  * %__GFP_COLD - Request cache-cold pages instead of
 132  *   trying to return cache-warm pages.
 133  *
 134  * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
 135  *
 136  * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
 137  *   (think twice before using).
 138  *
 139  * %__GFP_NORETRY - If memory is not immediately available,
 140  *   then give up at once.
 141  *
 142  * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
 143  *
 144  * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
 145  *
 146  * There are other flags available as well, but these are not intended
 147  * for general use, and so are not documented here. For a full list of
 148  * potential flags, always refer to linux/gfp.h.
 149  */
 150 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 151 {
 152         if (n != 0 && size > ULONG_MAX / n)
 153                 return NULL;
 154         return __kzalloc(n * size, flags);
 155 }
 156
 157 /*
 158  * Allocator specific definitions. These are mainly used to establish optimized
 159  * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
 160  * selecting the appropriate general cache at compile time.
 161  *
 162  * Allocators must define at least:
 163  *
 164  *      kmem_cache_alloc()
 165  *      __kmalloc()
 166  *      kmalloc()
 167  *      kzalloc()
 168  *
 169  * Those wishing to support NUMA must also define:
 170  *
 171  *      kmem_cache_alloc_node()
 172  *      kmalloc_node()
 173  *
 174  * See each allocator definition file for additional comments and
 175  * implementation notes.
 176  */
 177 #ifdef CONFIG_SLUB
 178 #include <linux/slub_def.h>
 179 #elif defined(CONFIG_SLOB)
 180 #include <linux/slob_def.h>
 181 #else
 182 #include <linux/slab_def.h>
 183 #endif
 184
 185 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
 186 /**
 187  * kmalloc_node - allocate memory from a specific node
 188  * @size: how many bytes of memory are required.
 189  * @flags: the type of memory to allocate (see kcalloc).
 190  * @node: node to allocate from.
 191  *
 192  * kmalloc() for non-local nodes, used to allocate from a specific node
 193  * if available. Equivalent to kmalloc() in the non-NUMA single-node
 194  * case.
 195  */
 196 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 197 {
 198         return kmalloc(size, flags);
 199 }
 200
 201 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 202 {
 203         return __kmalloc(size, flags);
 204 }
 205
 206 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 207
 208 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
 209                                         gfp_t flags, int node)
 210 {
 211         return kmem_cache_alloc(cachep, flags);
 212 }
 213 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
 214
 215 /*
 216  * kmalloc_track_caller is a special version of kmalloc that records the
 217  * calling function of the routine calling it for slab leak tracking instead
 218  * of just the calling function (confusing, eh?).
 219  * It's useful when the call to kmalloc comes from a widely-used standard
 220  * allocator where we care about the real place the memory allocation
 221  * request comes from.
 222  */
 223 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 224 extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
 225 #define kmalloc_track_caller(size, flags) \
 226         __kmalloc_track_caller(size, flags, __builtin_return_address(0))
 227 #else
 228 #define kmalloc_track_caller(size, flags) \
 229         __kmalloc(size, flags)
 230 #endif /* DEBUG_SLAB */
 231
 232 #ifdef CONFIG_NUMA
 233 /*
 234  * kmalloc_node_track_caller is a special version of kmalloc_node that
 235  * records the calling function of the routine calling it for slab leak
 236  * tracking instead of just the calling function (confusing, eh?).
 237  * It's useful when the call to kmalloc_node comes from a widely-used
 238  * standard allocator where we care about the real place the memory
 239  * allocation request comes from.
 240  */
 241 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 242 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
 243 #define kmalloc_node_track_caller(size, flags, node) \
 244         __kmalloc_node_track_caller(size, flags, node, \
 245                         __builtin_return_address(0))
 246 #else
 247 #define kmalloc_node_track_caller(size, flags, node) \
 248         __kmalloc_node(size, flags, node)
 249 #endif
 250
 251 #else /* CONFIG_NUMA */
 252
 253 #define kmalloc_node_track_caller(size, flags, node) \
 254         kmalloc_track_caller(size, flags)
 255
 256 #endif /* DEBUG_SLAB */
 257
 258 #endif  /* __KERNEL__ */
 259 #endif  /* _LINUX_SLAB_H */