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[PAGE_SHIFT];
  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 __always_inline int kmalloc_index(size_t size)
  82 {
  83         if (!size)
  84                 return 0;
  85
  86         if (size <= KMALLOC_MIN_SIZE)
  87                 return KMALLOC_SHIFT_LOW;
  88
  89         if (size > 64 && size <= 96)
  90                 return 1;
  91         if (size > 128 && size <= 192)
  92                 return 2;
  93         if (size <=          8) return 3;
  94         if (size <=         16) return 4;
  95         if (size <=         32) return 5;
  96         if (size <=         64) return 6;
  97         if (size <=        128) return 7;
  98         if (size <=        256) return 8;
  99         if (size <=        512) return 9;
 100         if (size <=       1024) return 10;
 101         if (size <=   2 * 1024) return 11;
 102 /*
 103  * The following is only needed to support architectures with a larger page
 104  * size than 4k.
 105  */
 106         if (size <=   4 * 1024) return 12;
 107         if (size <=   8 * 1024) return 13;
 108         if (size <=  16 * 1024) return 14;
 109         if (size <=  32 * 1024) return 15;
 110         if (size <=  64 * 1024) return 16;
 111         if (size <= 128 * 1024) return 17;
 112         if (size <= 256 * 1024) return 18;
 113         if (size <= 512 * 1024) return 19;
 114         if (size <= 1024 * 1024) return 20;
 115         if (size <=  2 * 1024 * 1024) return 21;
 116         return -1;
 117
 118 /*
 119  * What we really wanted to do and cannot do because of compiler issues is:
 120  *      int i;
 121  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 122  *              if (size <= (1 << i))
 123  *                      return i;
 124  */
 125 }
 126
 127 /*
 128  * Find the slab cache for a given combination of allocation flags and size.
 129  *
 130  * This ought to end up with a global pointer to the right cache
 131  * in kmalloc_caches.
 132  */
 133 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 134 {
 135         int index = kmalloc_index(size);
 136
 137         if (index == 0)
 138                 return NULL;
 139
 140         return &kmalloc_caches[index];
 141 }
 142
 143 #ifdef CONFIG_ZONE_DMA
 144 #define SLUB_DMA __GFP_DMA
 145 #else
 146 /* Disable DMA functionality */
 147 #define SLUB_DMA (__force gfp_t)0
 148 #endif
 149
 150 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 151 void *__kmalloc(size_t size, gfp_t flags);
 152
 153 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 154 {
 155         if (__builtin_constant_p(size)) {
 156                 if (size > PAGE_SIZE / 2)
 157                         return (void *)__get_free_pages(flags | __GFP_COMP,
 158                                                         get_order(size));
 159
 160                 if (!(flags & SLUB_DMA)) {
 161                         struct kmem_cache *s = kmalloc_slab(size);
 162
 163                         if (!s)
 164                                 return ZERO_SIZE_PTR;
 165
 166                         return kmem_cache_alloc(s, flags);
 167                 }
 168         }
 169         return __kmalloc(size, flags);
 170 }
 171
 172 #ifdef CONFIG_NUMA
 173 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 174 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 175
 176 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 177 {
 178         if (__builtin_constant_p(size) &&
 179                 size <= PAGE_SIZE / 2 && !(flags & SLUB_DMA)) {
 180                         struct kmem_cache *s = kmalloc_slab(size);
 181
 182                 if (!s)
 183                         return ZERO_SIZE_PTR;
 184
 185                 return kmem_cache_alloc_node(s, flags, node);
 186         }
 187         return __kmalloc_node(size, flags, node);
 188 }
 189 #endif
 190
 191 #endif /* _LINUX_SLUB_DEF_H */