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
   8  */
   9 #include <linux/types.h>
  10 #include <linux/gfp.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/kobject.h>
  13
  14 enum stat_item {
  15         ALLOC_FASTPATH,         /* Allocation from cpu slab */
  16         ALLOC_SLOWPATH,         /* Allocation by getting a new cpu slab */
  17         FREE_FASTPATH,          /* Free to cpu slub */
  18         FREE_SLOWPATH,          /* Freeing not to cpu slab */
  19         FREE_FROZEN,            /* Freeing to frozen slab */
  20         FREE_ADD_PARTIAL,       /* Freeing moves slab to partial list */
  21         FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
  22         ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from partial list */
  23         ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
  24         ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
  25         FREE_SLAB,              /* Slab freed to the page allocator */
  26         CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
  27         DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
  28         DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
  29         DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
  30         DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
  31         DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
  32         ORDER_FALLBACK,         /* Number of times fallback was necessary */
  33         NR_SLUB_STAT_ITEMS };
  34
  35 struct kmem_cache_cpu {
  36         void **freelist;        /* Pointer to first free per cpu object */
  37         struct page *page;      /* The slab from which we are allocating */
  38         int node;               /* The node of the page (or -1 for debug) */
  39         unsigned int offset;    /* Freepointer offset (in word units) */
  40         unsigned int objsize;   /* Size of an object (from kmem_cache) */
  41 #ifdef CONFIG_SLUB_STATS
  42         unsigned stat[NR_SLUB_STAT_ITEMS];
  43 #endif
  44 };
  45
  46 struct kmem_cache_node {
  47         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  48         unsigned long nr_partial;
  49         unsigned long min_partial;
  50         struct list_head partial;
  51 #ifdef CONFIG_SLUB_DEBUG
  52         atomic_long_t nr_slabs;
  53         atomic_long_t total_objects;
  54         struct list_head full;
  55 #endif
  56 };
  57
  58 /*
  59  * Word size structure that can be atomically updated or read and that
  60  * contains both the order and the number of objects that a slab of the
  61  * given order would contain.
  62  */
  63 struct kmem_cache_order_objects {
  64         unsigned long x;
  65 };
  66
  67 /*
  68  * Slab cache management.
  69  */
  70 struct kmem_cache {
  71         /* Used for retriving partial slabs etc */
  72         unsigned long flags;
  73         int size;               /* The size of an object including meta data */
  74         int objsize;            /* The size of an object without meta data */
  75         int offset;             /* Free pointer offset. */
  76         struct kmem_cache_order_objects oo;
  77
  78         /*
  79          * Avoid an extra cache line for UP, SMP and for the node local to
  80          * struct kmem_cache.
  81          */
  82         struct kmem_cache_node local_node;
  83
  84         /* Allocation and freeing of slabs */
  85         struct kmem_cache_order_objects max;
  86         struct kmem_cache_order_objects min;
  87         gfp_t allocflags;       /* gfp flags to use on each alloc */
  88         int refcount;           /* Refcount for slab cache destroy */
  89         void (*ctor)(void *);
  90         int inuse;              /* Offset to metadata */
  91         int align;              /* Alignment */
  92         const char *name;       /* Name (only for display!) */
  93         struct list_head list;  /* List of slab caches */
  94 #ifdef CONFIG_SLUB_DEBUG
  95         struct kobject kobj;    /* For sysfs */
  96 #endif
  97
  98 #ifdef CONFIG_NUMA
  99         /*
 100          * Defragmentation by allocating from a remote node.
 101          */
 102         int remote_node_defrag_ratio;
 103         struct kmem_cache_node *node[MAX_NUMNODES];
 104 #endif
 105 #ifdef CONFIG_SMP
 106         struct kmem_cache_cpu *cpu_slab[NR_CPUS];
 107 #else
 108         struct kmem_cache_cpu cpu_slab;
 109 #endif
 110 };
 111
 112 /*
 113  * Kmalloc subsystem.
 114  */
 115 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
 116 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
 117 #else
 118 #define KMALLOC_MIN_SIZE 8
 119 #endif
 120
 121 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 122
 123 /*
 124  * We keep the general caches in an array of slab caches that are used for
 125  * 2^x bytes of allocations.
 126  */
 127 extern struct kmem_cache kmalloc_caches[PAGE_SHIFT + 1];
 128
 129 /*
 130  * Sorry that the following has to be that ugly but some versions of GCC
 131  * have trouble with constant propagation and loops.
 132  */
 133 static __always_inline int kmalloc_index(size_t size)
 134 {
 135         if (!size)
 136                 return 0;
 137
 138         if (size <= KMALLOC_MIN_SIZE)
 139                 return KMALLOC_SHIFT_LOW;
 140
 141 #if KMALLOC_MIN_SIZE <= 64
 142         if (size > 64 && size <= 96)
 143                 return 1;
 144         if (size > 128 && size <= 192)
 145                 return 2;
 146 #endif
 147         if (size <=          8) return 3;
 148         if (size <=         16) return 4;
 149         if (size <=         32) return 5;
 150         if (size <=         64) return 6;
 151         if (size <=        128) return 7;
 152         if (size <=        256) return 8;
 153         if (size <=        512) return 9;
 154         if (size <=       1024) return 10;
 155         if (size <=   2 * 1024) return 11;
 156         if (size <=   4 * 1024) return 12;
 157 /*
 158  * The following is only needed to support architectures with a larger page
 159  * size than 4k.
 160  */
 161         if (size <=   8 * 1024) return 13;
 162         if (size <=  16 * 1024) return 14;
 163         if (size <=  32 * 1024) return 15;
 164         if (size <=  64 * 1024) return 16;
 165         if (size <= 128 * 1024) return 17;
 166         if (size <= 256 * 1024) return 18;
 167         if (size <= 512 * 1024) return 19;
 168         if (size <= 1024 * 1024) return 20;
 169         if (size <=  2 * 1024 * 1024) return 21;
 170         return -1;
 171
 172 /*
 173  * What we really wanted to do and cannot do because of compiler issues is:
 174  *      int i;
 175  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 176  *              if (size <= (1 << i))
 177  *                      return i;
 178  */
 179 }
 180
 181 /*
 182  * Find the slab cache for a given combination of allocation flags and size.
 183  *
 184  * This ought to end up with a global pointer to the right cache
 185  * in kmalloc_caches.
 186  */
 187 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 188 {
 189         int index = kmalloc_index(size);
 190
 191         if (index == 0)
 192                 return NULL;
 193
 194         return &kmalloc_caches[index];
 195 }
 196
 197 #ifdef CONFIG_ZONE_DMA
 198 #define SLUB_DMA __GFP_DMA
 199 #else
 200 /* Disable DMA functionality */
 201 #define SLUB_DMA (__force gfp_t)0
 202 #endif
 203
 204 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 205 void *__kmalloc(size_t size, gfp_t flags);
 206
 207 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 208 {
 209         return (void *)__get_free_pages(flags | __GFP_COMP, get_order(size));
 210 }
 211
 212 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 213 {
 214         if (__builtin_constant_p(size)) {
 215                 if (size > PAGE_SIZE)
 216                         return kmalloc_large(size, flags);
 217
 218                 if (!(flags & SLUB_DMA)) {
 219                         struct kmem_cache *s = kmalloc_slab(size);
 220
 221                         if (!s)
 222                                 return ZERO_SIZE_PTR;
 223
 224                         return kmem_cache_alloc(s, flags);
 225                 }
 226         }
 227         return __kmalloc(size, flags);
 228 }
 229
 230 #ifdef CONFIG_NUMA
 231 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 232 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 233
 234 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 235 {
 236         if (__builtin_constant_p(size) &&
 237                 size <= PAGE_SIZE && !(flags & SLUB_DMA)) {
 238                         struct kmem_cache *s = kmalloc_slab(size);
 239
 240                 if (!s)
 241                         return ZERO_SIZE_PTR;
 242
 243                 return kmem_cache_alloc_node(s, flags, node);
 244         }
 245         return __kmalloc_node(size, flags, node);
 246 }
 247 #endif
 248
 249 #endif /* _LINUX_SLUB_DEF_H */