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         unsigned 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         void (*dtor)(void *, struct kmem_cache *, unsigned long);
  44         int inuse;              /* Offset to metadata */
  45         int align;              /* Alignment */
  46         const char *name;       /* Name (only for display!) */
  47         struct list_head list;  /* List of slab caches */
  48         struct kobject kobj;    /* For sysfs */
  49
  50 #ifdef CONFIG_NUMA
  51         int defrag_ratio;
  52         struct kmem_cache_node *node[MAX_NUMNODES];
  53 #endif
  54         struct page *cpu_slab[NR_CPUS];
  55 };
  56
  57 /*
  58  * Kmalloc subsystem.
  59  */
  60 #define KMALLOC_SHIFT_LOW 3
  61
  62 #ifdef CONFIG_LARGE_ALLOCS
  63 #define KMALLOC_SHIFT_HIGH 25
  64 #else
  65 #if !defined(CONFIG_MMU) || NR_CPUS > 512 || MAX_NUMNODES > 256
  66 #define KMALLOC_SHIFT_HIGH 20
  67 #else
  68 #define KMALLOC_SHIFT_HIGH 18
  69 #endif
  70 #endif
  71
  72 /*
  73  * We keep the general caches in an array of slab caches that are used for
  74  * 2^x bytes of allocations.
  75  */
  76 extern struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
  77
  78 /*
  79  * Sorry that the following has to be that ugly but some versions of GCC
  80  * have trouble with constant propagation and loops.
  81  */
  82 static inline int kmalloc_index(int size)
  83 {
  84         /*
  85          * We should return 0 if size == 0 but we use the smallest object
  86          * here for SLAB legacy reasons.
  87          */
  88         WARN_ON_ONCE(size == 0);
  89
  90         if (size > 64 && size <= 96)
  91                 return 1;
  92         if (size > 128 && size <= 192)
  93                 return 2;
  94         if (size <=          8) return 3;
  95         if (size <=         16) return 4;
  96         if (size <=         32) return 5;
  97         if (size <=         64) return 6;
  98         if (size <=        128) return 7;
  99         if (size <=        256) return 8;
 100         if (size <=        512) return 9;
 101         if (size <=       1024) return 10;
 102         if (size <=   2 * 1024) return 11;
 103         if (size <=   4 * 1024) return 12;
 104         if (size <=   8 * 1024) return 13;
 105         if (size <=  16 * 1024) return 14;
 106         if (size <=  32 * 1024) return 15;
 107         if (size <=  64 * 1024) return 16;
 108         if (size <= 128 * 1024) return 17;
 109         if (size <= 256 * 1024) return 18;
 110 #if KMALLOC_SHIFT_HIGH > 18
 111         if (size <=  512 * 1024) return 19;
 112         if (size <= 1024 * 1024) return 20;
 113 #endif
 114 #if KMALLOC_SHIFT_HIGH > 20
 115         if (size <=  2 * 1024 * 1024) return 21;
 116         if (size <=  4 * 1024 * 1024) return 22;
 117         if (size <=  8 * 1024 * 1024) return 23;
 118         if (size <= 16 * 1024 * 1024) return 24;
 119         if (size <= 32 * 1024 * 1024) return 25;
 120 #endif
 121         return -1;
 122
 123 /*
 124  * What we really wanted to do and cannot do because of compiler issues is:
 125  *      int i;
 126  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 127  *              if (size <= (1 << i))
 128  *                      return i;
 129  */
 130 }
 131
 132 /*
 133  * Find the slab cache for a given combination of allocation flags and size.
 134  *
 135  * This ought to end up with a global pointer to the right cache
 136  * in kmalloc_caches.
 137  */
 138 static inline struct kmem_cache *kmalloc_slab(size_t size)
 139 {
 140         int index = kmalloc_index(size);
 141
 142         if (index == 0)
 143                 return NULL;
 144
 145         if (index < 0) {
 146                 /*
 147                  * Generate a link failure. Would be great if we could
 148                  * do something to stop the compile here.
 149                  */
 150                 extern void __kmalloc_size_too_large(void);
 151                 __kmalloc_size_too_large();
 152         }
 153         return &kmalloc_caches[index];
 154 }
 155
 156 #ifdef CONFIG_ZONE_DMA
 157 #define SLUB_DMA __GFP_DMA
 158 #else
 159 /* Disable DMA functionality */
 160 #define SLUB_DMA 0
 161 #endif
 162
 163 static inline void *kmalloc(size_t size, gfp_t flags)
 164 {
 165         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 166                 struct kmem_cache *s = kmalloc_slab(size);
 167
 168                 if (!s)
 169                         return NULL;
 170
 171                 return kmem_cache_alloc(s, flags);
 172         } else
 173                 return __kmalloc(size, flags);
 174 }
 175
 176 static inline void *kzalloc(size_t size, gfp_t flags)
 177 {
 178         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 179                 struct kmem_cache *s = kmalloc_slab(size);
 180
 181                 if (!s)
 182                         return NULL;
 183
 184                 return kmem_cache_zalloc(s, flags);
 185         } else
 186                 return __kzalloc(size, flags);
 187 }
 188
 189 #ifdef CONFIG_NUMA
 190 extern void *__kmalloc_node(size_t size, gfp_t flags, int node);
 191
 192 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 193 {
 194         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 195                 struct kmem_cache *s = kmalloc_slab(size);
 196
 197                 if (!s)
 198                         return NULL;
 199
 200                 return kmem_cache_alloc_node(s, flags, node);
 201         } else
 202                 return __kmalloc_node(size, flags, node);
 203 }
 204 #endif
 205
 206 #endif /* _LINUX_SLUB_DEF_H */