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_PANIC              0x00040000UL    /* Panic if kmem_cache_create() fails */
  28 #define SLAB_DESTROY_BY_RCU     0x00080000UL    /* Defer freeing slabs to RCU */
  29 #define SLAB_MEM_SPREAD         0x00100000UL    /* Spread some memory over cpuset */
  30 #define SLAB_TRACE              0x00200000UL    /* Trace allocations and frees */
  31
  32 /* The following flags affect the page allocator grouping pages by mobility */
  33 #define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
  34 #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
  35 /*
  36  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
  37  *
  38  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
  39  *
  40  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
  41  * Both make kfree a no-op.
  42  */
  43 #define ZERO_SIZE_PTR ((void *)16)
  44
  45 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
  46                                 (unsigned long)ZERO_SIZE_PTR)
  47
  48 /*
  49  * struct kmem_cache related prototypes
  50  */
  51 void __init kmem_cache_init(void);
  52 int slab_is_available(void);
  53
  54 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
  55                         unsigned long,
  56                         void (*)(struct kmem_cache *, void *));
  57 void kmem_cache_destroy(struct kmem_cache *);
  58 int kmem_cache_shrink(struct kmem_cache *);
  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)
  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 * __must_check krealloc(const void *, size_t, gfp_t);
  95 void kfree(const void *);
  96 size_t ksize(const void *);
  97
  98 /*
  99  * Allocator specific definitions. These are mainly used to establish optimized
 100  * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
 101  * selecting the appropriate general cache at compile time.
 102  *
 103  * Allocators must define at least:
 104  *
 105  *      kmem_cache_alloc()
 106  *      __kmalloc()
 107  *      kmalloc()
 108  *
 109  * Those wishing to support NUMA must also define:
 110  *
 111  *      kmem_cache_alloc_node()
 112  *      kmalloc_node()
 113  *
 114  * See each allocator definition file for additional comments and
 115  * implementation notes.
 116  */
 117 #ifdef CONFIG_SLUB
 118 #include <linux/slub_def.h>
 119 #elif defined(CONFIG_SLOB)
 120 #include <linux/slob_def.h>
 121 #else
 122 #include <linux/slab_def.h>
 123 #endif
 124
 125 /**
 126  * kcalloc - allocate memory for an array. The memory is set to zero.
 127  * @n: number of elements.
 128  * @size: element size.
 129  * @flags: the type of memory to allocate.
 130  *
 131  * The @flags argument may be one of:
 132  *
 133  * %GFP_USER - Allocate memory on behalf of user.  May sleep.
 134  *
 135  * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
 136  *
 137  * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
 138  *   For example, use this inside interrupt handlers.
 139  *
 140  * %GFP_HIGHUSER - Allocate pages from high memory.
 141  *
 142  * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
 143  *
 144  * %GFP_NOFS - Do not make any fs calls while trying to get memory.
 145  *
 146  * %GFP_NOWAIT - Allocation will not sleep.
 147  *
 148  * %GFP_THISNODE - Allocate node-local memory only.
 149  *
 150  * %GFP_DMA - Allocation suitable for DMA.
 151  *   Should only be used for kmalloc() caches. Otherwise, use a
 152  *   slab created with SLAB_DMA.
 153  *
 154  * Also it is possible to set different flags by OR'ing
 155  * in one or more of the following additional @flags:
 156  *
 157  * %__GFP_COLD - Request cache-cold pages instead of
 158  *   trying to return cache-warm pages.
 159  *
 160  * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
 161  *
 162  * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
 163  *   (think twice before using).
 164  *
 165  * %__GFP_NORETRY - If memory is not immediately available,
 166  *   then give up at once.
 167  *
 168  * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
 169  *
 170  * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
 171  *
 172  * There are other flags available as well, but these are not intended
 173  * for general use, and so are not documented here. For a full list of
 174  * potential flags, always refer to linux/gfp.h.
 175  */
 176 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 177 {
 178         if (n != 0 && size > ULONG_MAX / n)
 179                 return NULL;
 180         return __kmalloc(n * size, flags | __GFP_ZERO);
 181 }
 182
 183 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
 184 /**
 185  * kmalloc_node - allocate memory from a specific node
 186  * @size: how many bytes of memory are required.
 187  * @flags: the type of memory to allocate (see kcalloc).
 188  * @node: node to allocate from.
 189  *
 190  * kmalloc() for non-local nodes, used to allocate from a specific node
 191  * if available. Equivalent to kmalloc() in the non-NUMA single-node
 192  * case.
 193  */
 194 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 195 {
 196         return kmalloc(size, flags);
 197 }
 198
 199 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 200 {
 201         return __kmalloc(size, flags);
 202 }
 203
 204 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 205
 206 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
 207                                         gfp_t flags, int node)
 208 {
 209         return kmem_cache_alloc(cachep, flags);
 210 }
 211 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
 212
 213 /*
 214  * kmalloc_track_caller is a special version of kmalloc that records the
 215  * calling function of the routine calling it for slab leak tracking instead
 216  * of just the calling function (confusing, eh?).
 217  * It's useful when the call to kmalloc comes from a widely-used standard
 218  * allocator where we care about the real place the memory allocation
 219  * request comes from.
 220  */
 221 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 222 extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
 223 #define kmalloc_track_caller(size, flags) \
 224         __kmalloc_track_caller(size, flags, __builtin_return_address(0))
 225 #else
 226 #define kmalloc_track_caller(size, flags) \
 227         __kmalloc(size, flags)
 228 #endif /* DEBUG_SLAB */
 229
 230 #ifdef CONFIG_NUMA
 231 /*
 232  * kmalloc_node_track_caller is a special version of kmalloc_node that
 233  * records the calling function of the routine calling it for slab leak
 234  * tracking instead of just the calling function (confusing, eh?).
 235  * It's useful when the call to kmalloc_node comes from a widely-used
 236  * standard allocator where we care about the real place the memory
 237  * allocation request comes from.
 238  */
 239 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 240 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
 241 #define kmalloc_node_track_caller(size, flags, node) \
 242         __kmalloc_node_track_caller(size, flags, node, \
 243                         __builtin_return_address(0))
 244 #else
 245 #define kmalloc_node_track_caller(size, flags, node) \
 246         __kmalloc_node(size, flags, node)
 247 #endif
 248
 249 #else /* CONFIG_NUMA */
 250
 251 #define kmalloc_node_track_caller(size, flags, node) \
 252         kmalloc_track_caller(size, flags)
 253
 254 #endif /* DEBUG_SLAB */
 255
 256 /*
 257  * Shortcuts
 258  */
 259 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
 260 {
 261         return kmem_cache_alloc(k, flags | __GFP_ZERO);
 262 }
 263
 264 /**
 265  * kzalloc - allocate memory. The memory is set to zero.
 266  * @size: how many bytes of memory are required.
 267  * @flags: the type of memory to allocate (see kmalloc).
 268  */
 269 static inline void *kzalloc(size_t size, gfp_t flags)
 270 {
 271         return kmalloc(size, flags | __GFP_ZERO);
 272 }
 273
 274 #ifdef CONFIG_SLABINFO
 275 extern const struct seq_operations slabinfo_op;
 276 ssize_t slabinfo_write(struct file *, const char __user *, size_t, loff_t *);
 277 #endif
 278
 279 #endif  /* __KERNEL__ */
 280 #endif  /* _LINUX_SLAB_H */