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         /* Lots of wasted space */
  20 } ____cacheline_aligned_in_smp;
  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)(void *, struct kmem_cache *, unsigned long);
  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         struct kmem_cache_cpu cpu_slab[NR_CPUS];
  66 };
  67
  68 /*
  69  * Kmalloc subsystem.
  70  */
  71 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
  72 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
  73 #else
  74 #define KMALLOC_MIN_SIZE 8
  75 #endif
  76
  77 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
  78
  79 /*
  80  * We keep the general caches in an array of slab caches that are used for
  81  * 2^x bytes of allocations.
  82  */
  83 extern struct kmem_cache kmalloc_caches[PAGE_SHIFT];
  84
  85 /*
  86  * Sorry that the following has to be that ugly but some versions of GCC
  87  * have trouble with constant propagation and loops.
  88  */
  89 static __always_inline int kmalloc_index(size_t size)
  90 {
  91         if (!size)
  92                 return 0;
  93
  94         if (size <= KMALLOC_MIN_SIZE)
  95                 return KMALLOC_SHIFT_LOW;
  96
  97         if (size > 64 && size <= 96)
  98                 return 1;
  99         if (size > 128 && size <= 192)
 100                 return 2;
 101         if (size <=          8) return 3;
 102         if (size <=         16) return 4;
 103         if (size <=         32) return 5;
 104         if (size <=         64) return 6;
 105         if (size <=        128) return 7;
 106         if (size <=        256) return 8;
 107         if (size <=        512) return 9;
 108         if (size <=       1024) return 10;
 109         if (size <=   2 * 1024) return 11;
 110 /*
 111  * The following is only needed to support architectures with a larger page
 112  * size than 4k.
 113  */
 114         if (size <=   4 * 1024) return 12;
 115         if (size <=   8 * 1024) return 13;
 116         if (size <=  16 * 1024) return 14;
 117         if (size <=  32 * 1024) return 15;
 118         if (size <=  64 * 1024) return 16;
 119         if (size <= 128 * 1024) return 17;
 120         if (size <= 256 * 1024) return 18;
 121         if (size <= 512 * 1024) return 19;
 122         if (size <= 1024 * 1024) return 20;
 123         if (size <=  2 * 1024 * 1024) return 21;
 124         return -1;
 125
 126 /*
 127  * What we really wanted to do and cannot do because of compiler issues is:
 128  *      int i;
 129  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 130  *              if (size <= (1 << i))
 131  *                      return i;
 132  */
 133 }
 134
 135 /*
 136  * Find the slab cache for a given combination of allocation flags and size.
 137  *
 138  * This ought to end up with a global pointer to the right cache
 139  * in kmalloc_caches.
 140  */
 141 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 142 {
 143         int index = kmalloc_index(size);
 144
 145         if (index == 0)
 146                 return NULL;
 147
 148         return &kmalloc_caches[index];
 149 }
 150
 151 #ifdef CONFIG_ZONE_DMA
 152 #define SLUB_DMA __GFP_DMA
 153 #else
 154 /* Disable DMA functionality */
 155 #define SLUB_DMA (__force gfp_t)0
 156 #endif
 157
 158 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 159 void *__kmalloc(size_t size, gfp_t flags);
 160
 161 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 162 {
 163         if (__builtin_constant_p(size)) {
 164                 if (size > PAGE_SIZE / 2)
 165                         return (void *)__get_free_pages(flags | __GFP_COMP,
 166                                                         get_order(size));
 167
 168                 if (!(flags & SLUB_DMA)) {
 169                         struct kmem_cache *s = kmalloc_slab(size);
 170
 171                         if (!s)
 172                                 return ZERO_SIZE_PTR;
 173
 174                         return kmem_cache_alloc(s, flags);
 175                 }
 176         }
 177         return __kmalloc(size, flags);
 178 }
 179
 180 #ifdef CONFIG_NUMA
 181 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 182 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 183
 184 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 185 {
 186         if (__builtin_constant_p(size) &&
 187                 size <= PAGE_SIZE / 2 && !(flags & SLUB_DMA)) {
 188                         struct kmem_cache *s = kmalloc_slab(size);
 189
 190                 if (!s)
 191                         return ZERO_SIZE_PTR;
 192
 193                 return kmem_cache_alloc_node(s, flags, node);
 194         }
 195         return __kmalloc_node(size, flags, node);
 196 }
 197 #endif
 198
 199 #endif /* _LINUX_SLUB_DEF_H */