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_cpu {
  15         void **freelist;
  16         struct page *page;
  17         int node;
  18         unsigned int offset;
  19         unsigned int objsize;
  20 };
  21
  22 struct kmem_cache_node {
  23         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  24         unsigned long nr_partial;
  25         atomic_long_t nr_slabs;
  26         struct list_head partial;
  27 #ifdef CONFIG_SLUB_DEBUG
  28         struct list_head full;
  29 #endif
  30 };
  31
  32 /*
  33  * Slab cache management.
  34  */
  35 struct kmem_cache {
  36         /* Used for retriving partial slabs etc */
  37         unsigned long flags;
  38         int size;               /* The size of an object including meta data */
  39         int objsize;            /* The size of an object without meta data */
  40         int offset;             /* Free pointer offset. */
  41         int order;
  42
  43         /*
  44          * Avoid an extra cache line for UP, SMP and for the node local to
  45          * struct kmem_cache.
  46          */
  47         struct kmem_cache_node local_node;
  48
  49         /* Allocation and freeing of slabs */
  50         int objects;            /* Number of objects in slab */
  51         int refcount;           /* Refcount for slab cache destroy */
  52         void (*ctor)(struct kmem_cache *, void *);
  53         int inuse;              /* Offset to metadata */
  54         int align;              /* Alignment */
  55         const char *name;       /* Name (only for display!) */
  56         struct list_head list;  /* List of slab caches */
  57 #ifdef CONFIG_SLUB_DEBUG
  58         struct kobject kobj;    /* For sysfs */
  59 #endif
  60
  61 #ifdef CONFIG_NUMA
  62         int defrag_ratio;
  63         struct kmem_cache_node *node[MAX_NUMNODES];
  64 #endif
  65 #ifdef CONFIG_SMP
  66         struct kmem_cache_cpu *cpu_slab[NR_CPUS];
  67 #else
  68         struct kmem_cache_cpu cpu_slab;
  69 #endif
  70 };
  71
  72 /*
  73  * Kmalloc subsystem.
  74  */
  75 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
  76 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
  77 #else
  78 #define KMALLOC_MIN_SIZE 8
  79 #endif
  80
  81 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
  82
  83 /*
  84  * We keep the general caches in an array of slab caches that are used for
  85  * 2^x bytes of allocations.
  86  */
  87 extern struct kmem_cache kmalloc_caches[PAGE_SHIFT];
  88
  89 /*
  90  * Sorry that the following has to be that ugly but some versions of GCC
  91  * have trouble with constant propagation and loops.
  92  */
  93 static __always_inline int kmalloc_index(size_t size)
  94 {
  95         if (!size)
  96                 return 0;
  97
  98         if (size <= KMALLOC_MIN_SIZE)
  99                 return KMALLOC_SHIFT_LOW;
 100
 101         if (size > 64 && size <= 96)
 102                 return 1;
 103         if (size > 128 && size <= 192)
 104                 return 2;
 105         if (size <=          8) return 3;
 106         if (size <=         16) return 4;
 107         if (size <=         32) return 5;
 108         if (size <=         64) return 6;
 109         if (size <=        128) return 7;
 110         if (size <=        256) return 8;
 111         if (size <=        512) return 9;
 112         if (size <=       1024) return 10;
 113         if (size <=   2 * 1024) return 11;
 114 /*
 115  * The following is only needed to support architectures with a larger page
 116  * size than 4k.
 117  */
 118         if (size <=   4 * 1024) return 12;
 119         if (size <=   8 * 1024) return 13;
 120         if (size <=  16 * 1024) return 14;
 121         if (size <=  32 * 1024) return 15;
 122         if (size <=  64 * 1024) return 16;
 123         if (size <= 128 * 1024) return 17;
 124         if (size <= 256 * 1024) return 18;
 125         if (size <= 512 * 1024) return 19;
 126         if (size <= 1024 * 1024) return 20;
 127         if (size <=  2 * 1024 * 1024) return 21;
 128         return -1;
 129
 130 /*
 131  * What we really wanted to do and cannot do because of compiler issues is:
 132  *      int i;
 133  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 134  *              if (size <= (1 << i))
 135  *                      return i;
 136  */
 137 }
 138
 139 /*
 140  * Find the slab cache for a given combination of allocation flags and size.
 141  *
 142  * This ought to end up with a global pointer to the right cache
 143  * in kmalloc_caches.
 144  */
 145 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 146 {
 147         int index = kmalloc_index(size);
 148
 149         if (index == 0)
 150                 return NULL;
 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 (__force gfp_t)0
 160 #endif
 161
 162 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 163 void *__kmalloc(size_t size, gfp_t flags);
 164
 165 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 166 {
 167         if (__builtin_constant_p(size)) {
 168                 if (size > PAGE_SIZE / 2)
 169                         return (void *)__get_free_pages(flags | __GFP_COMP,
 170                                                         get_order(size));
 171
 172                 if (!(flags & SLUB_DMA)) {
 173                         struct kmem_cache *s = kmalloc_slab(size);
 174
 175                         if (!s)
 176                                 return ZERO_SIZE_PTR;
 177
 178                         return kmem_cache_alloc(s, flags);
 179                 }
 180         }
 181         return __kmalloc(size, flags);
 182 }
 183
 184 #ifdef CONFIG_NUMA
 185 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 186 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 187
 188 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 189 {
 190         if (__builtin_constant_p(size) &&
 191                 size <= PAGE_SIZE / 2 && !(flags & SLUB_DMA)) {
 192                         struct kmem_cache *s = kmalloc_slab(size);
 193
 194                 if (!s)
 195                         return ZERO_SIZE_PTR;
 196
 197                 return kmem_cache_alloc_node(s, flags, node);
 198         }
 199         return __kmalloc_node(size, flags, node);
 200 }
 201 #endif
 202
 203 #endif /* _LINUX_SLUB_DEF_H */