include/linux/slub_def.h

   1 #ifndef _LINUX_SLUB_DEF_H
   2 #define _LINUX_SLUB_DEF_H
   3
   4 /*
   5  * SLUB : A Slab allocator without object queues.
   6  *
   7  * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
   8  */
   9 #include <linux/types.h>
  10 #include <linux/gfp.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/kobject.h>
  13
  14 struct kmem_cache_node {
  15         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  16         unsigned long nr_partial;
  17         atomic_long_t nr_slabs;
  18         struct list_head partial;
  19         struct list_head full;
  20 };
  21
  22 /*
  23  * Slab cache management.
  24  */
  25 struct kmem_cache {
  26         /* Used for retriving partial slabs etc */
  27         unsigned long flags;
  28         int size;               /* The size of an object including meta data */
  29         int objsize;            /* The size of an object without meta data */
  30         int offset;             /* Free pointer offset. */
  31         int order;
  32
  33         /*
  34          * Avoid an extra cache line for UP, SMP and for the node local to
  35          * struct kmem_cache.
  36          */
  37         struct kmem_cache_node local_node;
  38
  39         /* Allocation and freeing of slabs */
  40         int objects;            /* Number of objects in slab */
  41         int refcount;           /* Refcount for slab cache destroy */
  42         void (*ctor)(void *, struct kmem_cache *, unsigned long);
  43         int inuse;              /* Offset to metadata */
  44         int align;              /* Alignment */
  45         const char *name;       /* Name (only for display!) */
  46         struct list_head list;  /* List of slab caches */
  47         struct kobject kobj;    /* For sysfs */
  48
  49 #ifdef CONFIG_NUMA
  50         int defrag_ratio;
  51         struct kmem_cache_node *node[MAX_NUMNODES];
  52 #endif
  53         struct page *cpu_slab[NR_CPUS];
  54 };
  55
  56 /*
  57  * Kmalloc subsystem.
  58  */
  59 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
  60 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
  61 #else
  62 #define KMALLOC_MIN_SIZE 8
  63 #endif
  64
  65 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
  66
  67 /*
  68  * We keep the general caches in an array of slab caches that are used for
  69  * 2^x bytes of allocations.
  70  */
  71 extern struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
  72
  73 /*
  74  * Sorry that the following has to be that ugly but some versions of GCC
  75  * have trouble with constant propagation and loops.
  76  */
  77 static inline int kmalloc_index(size_t size)
  78 {
  79         if (!size)
  80                 return 0;
  81
  82         if (size > KMALLOC_MAX_SIZE)
  83                 return -1;
  84
  85         if (size <= KMALLOC_MIN_SIZE)
  86                 return KMALLOC_SHIFT_LOW;
  87
  88         if (size > 64 && size <= 96)
  89                 return 1;
  90         if (size > 128 && size <= 192)
  91                 return 2;
  92         if (size <=          8) return 3;
  93         if (size <=         16) return 4;
  94         if (size <=         32) return 5;
  95         if (size <=         64) return 6;
  96         if (size <=        128) return 7;
  97         if (size <=        256) return 8;
  98         if (size <=        512) return 9;
  99         if (size <=       1024) return 10;
 100         if (size <=   2 * 1024) return 11;
 101         if (size <=   4 * 1024) return 12;
 102         if (size <=   8 * 1024) return 13;
 103         if (size <=  16 * 1024) return 14;
 104         if (size <=  32 * 1024) return 15;
 105         if (size <=  64 * 1024) return 16;
 106         if (size <= 128 * 1024) return 17;
 107         if (size <= 256 * 1024) return 18;
 108         if (size <=  512 * 1024) return 19;
 109         if (size <= 1024 * 1024) return 20;
 110         if (size <=  2 * 1024 * 1024) return 21;
 111         if (size <=  4 * 1024 * 1024) return 22;
 112         if (size <=  8 * 1024 * 1024) return 23;
 113         if (size <= 16 * 1024 * 1024) return 24;
 114         if (size <= 32 * 1024 * 1024) return 25;
 115         return -1;
 116
 117 /*
 118  * What we really wanted to do and cannot do because of compiler issues is:
 119  *      int i;
 120  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 121  *              if (size <= (1 << i))
 122  *                      return i;
 123  */
 124 }
 125
 126 /*
 127  * Find the slab cache for a given combination of allocation flags and size.
 128  *
 129  * This ought to end up with a global pointer to the right cache
 130  * in kmalloc_caches.
 131  */
 132 static inline struct kmem_cache *kmalloc_slab(size_t size)
 133 {
 134         int index = kmalloc_index(size);
 135
 136         if (index == 0)
 137                 return NULL;
 138
 139         /*
 140          * This function only gets expanded if __builtin_constant_p(size), so
 141          * testing it here shouldn't be needed.  But some versions of gcc need
 142          * help.
 143          */
 144         if (__builtin_constant_p(size) && index < 0) {
 145                 /*
 146                  * Generate a link failure. Would be great if we could
 147                  * do something to stop the compile here.
 148                  */
 149                 extern void __kmalloc_size_too_large(void);
 150                 __kmalloc_size_too_large();
 151         }
 152         return &kmalloc_caches[index];
 153 }
 154
 155 #ifdef CONFIG_ZONE_DMA
 156 #define SLUB_DMA __GFP_DMA
 157 #else
 158 /* Disable DMA functionality */
 159 #define SLUB_DMA 0
 160 #endif
 161
 162
 163 /*
 164  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
 165  *
 166  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
 167  *
 168  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
 169  * Both make kfree a no-op.
 170  */
 171 #define ZERO_SIZE_PTR ((void *)16)
 172
 173
 174 static inline void *kmalloc(size_t size, gfp_t flags)
 175 {
 176         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 177                 struct kmem_cache *s = kmalloc_slab(size);
 178
 179                 if (!s)
 180                         return ZERO_SIZE_PTR;
 181
 182                 return kmem_cache_alloc(s, flags);
 183         } else
 184                 return __kmalloc(size, flags);
 185 }
 186
 187 static inline void *kzalloc(size_t size, gfp_t flags)
 188 {
 189         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 190                 struct kmem_cache *s = kmalloc_slab(size);
 191
 192                 if (!s)
 193                         return ZERO_SIZE_PTR;
 194
 195                 return kmem_cache_zalloc(s, flags);
 196         } else
 197                 return __kzalloc(size, flags);
 198 }
 199
 200 #ifdef CONFIG_NUMA
 201 extern void *__kmalloc_node(size_t size, gfp_t flags, int node);
 202
 203 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 204 {
 205         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 206                 struct kmem_cache *s = kmalloc_slab(size);
 207
 208                 if (!s)
 209                         return ZERO_SIZE_PTR;
 210
 211                 return kmem_cache_alloc_node(s, flags, node);
 212         } else
 213                 return __kmalloc_node(size, flags, node);
 214 }
 215 #endif
 216
 217 #endif /* _LINUX_SLUB_DEF_H */