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 #ifdef CONFIG_SLUB_DEBUG
  20         struct list_head full;
  21 #endif
  22 };
  23
  24 /*
  25  * Slab cache management.
  26  */
  27 struct kmem_cache {
  28         /* Used for retriving partial slabs etc */
  29         unsigned long flags;
  30         int size;               /* The size of an object including meta data */
  31         int objsize;            /* The size of an object without meta data */
  32         int offset;             /* Free pointer offset. */
  33         int order;
  34
  35         /*
  36          * Avoid an extra cache line for UP, SMP and for the node local to
  37          * struct kmem_cache.
  38          */
  39         struct kmem_cache_node local_node;
  40
  41         /* Allocation and freeing of slabs */
  42         int objects;            /* Number of objects in slab */
  43         int refcount;           /* Refcount for slab cache destroy */
  44         void (*ctor)(void *, struct kmem_cache *, unsigned long);
  45         int inuse;              /* Offset to metadata */
  46         int align;              /* Alignment */
  47         const char *name;       /* Name (only for display!) */
  48         struct list_head list;  /* List of slab caches */
  49 #ifdef CONFIG_SLUB_DEBUG
  50         struct kobject kobj;    /* For sysfs */
  51 #endif
  52
  53 #ifdef CONFIG_NUMA
  54         int defrag_ratio;
  55         struct kmem_cache_node *node[MAX_NUMNODES];
  56 #endif
  57         struct page *cpu_slab[NR_CPUS];
  58 };
  59
  60 /*
  61  * Kmalloc subsystem.
  62  */
  63 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
  64 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
  65 #else
  66 #define KMALLOC_MIN_SIZE 8
  67 #endif
  68
  69 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
  70
  71 /*
  72  * We keep the general caches in an array of slab caches that are used for
  73  * 2^x bytes of allocations.
  74  */
  75 extern struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
  76
  77 /*
  78  * Sorry that the following has to be that ugly but some versions of GCC
  79  * have trouble with constant propagation and loops.
  80  */
  81 static inline int kmalloc_index(size_t size)
  82 {
  83         if (!size)
  84                 return 0;
  85
  86         if (size > KMALLOC_MAX_SIZE)
  87                 return -1;
  88
  89         if (size <= KMALLOC_MIN_SIZE)
  90                 return KMALLOC_SHIFT_LOW;
  91
  92         if (size > 64 && size <= 96)
  93                 return 1;
  94         if (size > 128 && size <= 192)
  95                 return 2;
  96         if (size <=          8) return 3;
  97         if (size <=         16) return 4;
  98         if (size <=         32) return 5;
  99         if (size <=         64) return 6;
 100         if (size <=        128) return 7;
 101         if (size <=        256) return 8;
 102         if (size <=        512) return 9;
 103         if (size <=       1024) return 10;
 104         if (size <=   2 * 1024) return 11;
 105         if (size <=   4 * 1024) return 12;
 106         if (size <=   8 * 1024) return 13;
 107         if (size <=  16 * 1024) return 14;
 108         if (size <=  32 * 1024) return 15;
 109         if (size <=  64 * 1024) return 16;
 110         if (size <= 128 * 1024) return 17;
 111         if (size <= 256 * 1024) return 18;
 112         if (size <=  512 * 1024) return 19;
 113         if (size <= 1024 * 1024) return 20;
 114         if (size <=  2 * 1024 * 1024) return 21;
 115         if (size <=  4 * 1024 * 1024) return 22;
 116         if (size <=  8 * 1024 * 1024) return 23;
 117         if (size <= 16 * 1024 * 1024) return 24;
 118         if (size <= 32 * 1024 * 1024) return 25;
 119         return -1;
 120
 121 /*
 122  * What we really wanted to do and cannot do because of compiler issues is:
 123  *      int i;
 124  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 125  *              if (size <= (1 << i))
 126  *                      return i;
 127  */
 128 }
 129
 130 /*
 131  * Find the slab cache for a given combination of allocation flags and size.
 132  *
 133  * This ought to end up with a global pointer to the right cache
 134  * in kmalloc_caches.
 135  */
 136 static inline struct kmem_cache *kmalloc_slab(size_t size)
 137 {
 138         int index = kmalloc_index(size);
 139
 140         if (index == 0)
 141                 return NULL;
 142
 143         /*
 144          * This function only gets expanded if __builtin_constant_p(size), so
 145          * testing it here shouldn't be needed.  But some versions of gcc need
 146          * help.
 147          */
 148         if (__builtin_constant_p(size) && index < 0) {
 149                 /*
 150                  * Generate a link failure. Would be great if we could
 151                  * do something to stop the compile here.
 152                  */
 153                 extern void __kmalloc_size_too_large(void);
 154                 __kmalloc_size_too_large();
 155         }
 156         return &kmalloc_caches[index];
 157 }
 158
 159 #ifdef CONFIG_ZONE_DMA
 160 #define SLUB_DMA __GFP_DMA
 161 #else
 162 /* Disable DMA functionality */
 163 #define SLUB_DMA (__force gfp_t)0
 164 #endif
 165
 166 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 167 void *__kmalloc(size_t size, gfp_t flags);
 168
 169 static inline void *kmalloc(size_t size, gfp_t flags)
 170 {
 171         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 172                 struct kmem_cache *s = kmalloc_slab(size);
 173
 174                 if (!s)
 175                         return ZERO_SIZE_PTR;
 176
 177                 return kmem_cache_alloc(s, flags);
 178         } else
 179                 return __kmalloc(size, flags);
 180 }
 181
 182 #ifdef CONFIG_NUMA
 183 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 184 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 185
 186 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 187 {
 188         if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
 189                 struct kmem_cache *s = kmalloc_slab(size);
 190
 191                 if (!s)
 192                         return ZERO_SIZE_PTR;
 193
 194                 return kmem_cache_alloc_node(s, flags, node);
 195         } else
 196                 return __kmalloc_node(size, flags, node);
 197 }
 198 #endif
 199
 200 #endif /* _LINUX_SLUB_DEF_H */