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