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 #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 #define SLAB_DESTROY_BY_RCU     0x00080000UL    /* Defer freeing slabs to RCU */
  27 #define SLAB_MEM_SPREAD         0x00100000UL    /* Spread some memory over cpuset */
  28 #define SLAB_TRACE              0x00200000UL    /* Trace allocations and frees */
  29
  30 /* Flag to prevent checks on free */
  31 #ifdef CONFIG_DEBUG_OBJECTS
  32 # define SLAB_DEBUG_OBJECTS     0x00400000UL
  33 #else
  34 # define SLAB_DEBUG_OBJECTS     0x00000000UL
  35 #endif
  36
  37 /* The following flags affect the page allocator grouping pages by mobility */
  38 #define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
  39 #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
  40 /*
  41  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
  42  *
  43  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
  44  *
  45  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
  46  * Both make kfree a no-op.
  47  */
  48 #define ZERO_SIZE_PTR ((void *)16)
  49
  50 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
  51                                 (unsigned long)ZERO_SIZE_PTR)
  52
  53 /*
  54  * struct kmem_cache related prototypes
  55  */
  56 void __init kmem_cache_init(void);
  57 int slab_is_available(void);
  58
  59 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
  60                         unsigned long,
  61                         void (*)(struct kmem_cache *, void *));
  62 void kmem_cache_destroy(struct kmem_cache *);
  63 int kmem_cache_shrink(struct kmem_cache *);
  64 void kmem_cache_free(struct kmem_cache *, void *);
  65 unsigned int kmem_cache_size(struct kmem_cache *);
  66 const char *kmem_cache_name(struct kmem_cache *);
  67 int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
  68
  69 /*
  70  * Please use this macro to create slab caches. Simply specify the
  71  * name of the structure and maybe some flags that are listed above.
  72  *
  73  * The alignment of the struct determines object alignment. If you
  74  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
  75  * then the objects will be properly aligned in SMP configurations.
  76  */
  77 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
  78                 sizeof(struct __struct), __alignof__(struct __struct),\
  79                 (__flags), NULL)
  80
  81 /*
  82  * The largest kmalloc size supported by the slab allocators is
  83  * 32 megabyte (2^25) or the maximum allocatable page order if that is
  84  * less than 32 MB.
  85  *
  86  * WARNING: Its not easy to increase this value since the allocators have
  87  * to do various tricks to work around compiler limitations in order to
  88  * ensure proper constant folding.
  89  */
  90 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
  91                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
  92
  93 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_HIGH)
  94 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
  95
  96 /*
  97  * Common kmalloc functions provided by all allocators
  98  */
  99 void * __must_check krealloc(const void *, size_t, gfp_t);
 100 void kfree(const void *);
 101 size_t ksize(const void *);
 102
 103 /*
 104  * Allocator specific definitions. These are mainly used to establish optimized
 105  * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
 106  * selecting the appropriate general cache at compile time.
 107  *
 108  * Allocators must define at least:
 109  *
 110  *      kmem_cache_alloc()
 111  *      __kmalloc()
 112  *      kmalloc()
 113  *
 114  * Those wishing to support NUMA must also define:
 115  *
 116  *      kmem_cache_alloc_node()
 117  *      kmalloc_node()
 118  *
 119  * See each allocator definition file for additional comments and
 120  * implementation notes.
 121  */
 122 #ifdef CONFIG_SLUB
 123 #include <linux/slub_def.h>
 124 #elif defined(CONFIG_SLOB)
 125 #include <linux/slob_def.h>
 126 #else
 127 #include <linux/slab_def.h>
 128 #endif
 129
 130 /**
 131  * kcalloc - allocate memory for an array. The memory is set to zero.
 132  * @n: number of elements.
 133  * @size: element size.
 134  * @flags: the type of memory to allocate.
 135  *
 136  * The @flags argument may be one of:
 137  *
 138  * %GFP_USER - Allocate memory on behalf of user.  May sleep.
 139  *
 140  * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
 141  *
 142  * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
 143  *   For example, use this inside interrupt handlers.
 144  *
 145  * %GFP_HIGHUSER - Allocate pages from high memory.
 146  *
 147  * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
 148  *
 149  * %GFP_NOFS - Do not make any fs calls while trying to get memory.
 150  *
 151  * %GFP_NOWAIT - Allocation will not sleep.
 152  *
 153  * %GFP_THISNODE - Allocate node-local memory only.
 154  *
 155  * %GFP_DMA - Allocation suitable for DMA.
 156  *   Should only be used for kmalloc() caches. Otherwise, use a
 157  *   slab created with SLAB_DMA.
 158  *
 159  * Also it is possible to set different flags by OR'ing
 160  * in one or more of the following additional @flags:
 161  *
 162  * %__GFP_COLD - Request cache-cold pages instead of
 163  *   trying to return cache-warm pages.
 164  *
 165  * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
 166  *
 167  * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
 168  *   (think twice before using).
 169  *
 170  * %__GFP_NORETRY - If memory is not immediately available,
 171  *   then give up at once.
 172  *
 173  * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
 174  *
 175  * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
 176  *
 177  * There are other flags available as well, but these are not intended
 178  * for general use, and so are not documented here. For a full list of
 179  * potential flags, always refer to linux/gfp.h.
 180  */
 181 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 182 {
 183         if (n != 0 && size > ULONG_MAX / n)
 184                 return NULL;
 185         return __kmalloc(n * size, flags | __GFP_ZERO);
 186 }
 187
 188 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
 189 /**
 190  * kmalloc_node - allocate memory from a specific node
 191  * @size: how many bytes of memory are required.
 192  * @flags: the type of memory to allocate (see kcalloc).
 193  * @node: node to allocate from.
 194  *
 195  * kmalloc() for non-local nodes, used to allocate from a specific node
 196  * if available. Equivalent to kmalloc() in the non-NUMA single-node
 197  * case.
 198  */
 199 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 200 {
 201         return kmalloc(size, flags);
 202 }
 203
 204 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 205 {
 206         return __kmalloc(size, flags);
 207 }
 208
 209 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 210
 211 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
 212                                         gfp_t flags, int node)
 213 {
 214         return kmem_cache_alloc(cachep, flags);
 215 }
 216 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
 217
 218 /*
 219  * kmalloc_track_caller is a special version of kmalloc that records the
 220  * calling function of the routine calling it for slab leak tracking instead
 221  * of just the calling function (confusing, eh?).
 222  * It's useful when the call to kmalloc comes from a widely-used standard
 223  * allocator where we care about the real place the memory allocation
 224  * request comes from.
 225  */
 226 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 227 extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
 228 #define kmalloc_track_caller(size, flags) \
 229         __kmalloc_track_caller(size, flags, __builtin_return_address(0))
 230 #else
 231 #define kmalloc_track_caller(size, flags) \
 232         __kmalloc(size, flags)
 233 #endif /* DEBUG_SLAB */
 234
 235 #ifdef CONFIG_NUMA
 236 /*
 237  * kmalloc_node_track_caller is a special version of kmalloc_node that
 238  * records the calling function of the routine calling it for slab leak
 239  * tracking instead of just the calling function (confusing, eh?).
 240  * It's useful when the call to kmalloc_node comes from a widely-used
 241  * standard allocator where we care about the real place the memory
 242  * allocation request comes from.
 243  */
 244 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
 245 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
 246 #define kmalloc_node_track_caller(size, flags, node) \
 247         __kmalloc_node_track_caller(size, flags, node, \
 248                         __builtin_return_address(0))
 249 #else
 250 #define kmalloc_node_track_caller(size, flags, node) \
 251         __kmalloc_node(size, flags, node)
 252 #endif
 253
 254 #else /* CONFIG_NUMA */
 255
 256 #define kmalloc_node_track_caller(size, flags, node) \
 257         kmalloc_track_caller(size, flags)
 258
 259 #endif /* DEBUG_SLAB */
 260
 261 /*
 262  * Shortcuts
 263  */
 264 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
 265 {
 266         return kmem_cache_alloc(k, flags | __GFP_ZERO);
 267 }
 268
 269 /**
 270  * kzalloc - allocate memory. The memory is set to zero.
 271  * @size: how many bytes of memory are required.
 272  * @flags: the type of memory to allocate (see kmalloc).
 273  */
 274 static inline void *kzalloc(size_t size, gfp_t flags)
 275 {
 276         return kmalloc(size, flags | __GFP_ZERO);
 277 }
 278
 279 #ifdef CONFIG_SLABINFO
 280 extern const struct seq_operations slabinfo_op;
 281 ssize_t slabinfo_write(struct file *, const char __user *, size_t, loff_t *);
 282 #endif
 283
 284 #endif  /* _LINUX_SLAB_H */