LXR linux/include/linux/slub

   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
  14struct kmem_cache_cpu {
  15        void **freelist;
  16        struct page *page;
  17        int node;
  18        unsigned int offset;
  19        unsigned int objsize;
  20};
  21
  22struct 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 */
  35struct 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 */
  87extern 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 */
  93static __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 */
 145static __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
 162void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 163void *__kmalloc(size_t size, gfp_t flags);
 164
 165static __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
 185void *__kmalloc_node(size_t size, gfp_t flags, int node);
 186void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 187
 188static __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 */
 204