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         struct list_head partial;
  50 #ifdef CONFIG_SLUB_DEBUG
  51         atomic_long_t nr_slabs;
  52         atomic_long_t total_objects;
  53         struct list_head full;
  54 #endif
  55 };
  56
  57 /*
  58  * Word size structure that can be atomically updated or read and that
  59  * contains both the order and the number of objects that a slab of the
  60  * given order would contain.
  61  */
  62 struct kmem_cache_order_objects {
  63         unsigned long x;
  64 };
  65
  66 /*
  67  * Slab cache management.
  68  */
  69 struct kmem_cache {
  70         /* Used for retriving partial slabs etc */
  71         unsigned long flags;
  72         int size;               /* The size of an object including meta data */
  73         int objsize;            /* The size of an object without meta data */
  74         int offset;             /* Free pointer offset. */
  75         struct kmem_cache_order_objects oo;
  76
  77         /*
  78          * Avoid an extra cache line for UP, SMP and for the node local to
  79          * struct kmem_cache.
  80          */
  81         struct kmem_cache_node local_node;
  82
  83         /* Allocation and freeing of slabs */
  84         struct kmem_cache_order_objects max;
  85         struct kmem_cache_order_objects min;
  86         gfp_t allocflags;       /* gfp flags to use on each alloc */
  87         int refcount;           /* Refcount for slab cache destroy */
  88         void (*ctor)(void *);
  89         int inuse;              /* Offset to metadata */
  90         int align;              /* Alignment */
  91         unsigned long min_partial;
  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  * Maximum kmalloc object size handled by SLUB. Larger object allocations
 125  * are passed through to the page allocator. The page allocator "fastpath"
 126  * is relatively slow so we need this value sufficiently high so that
 127  * performance critical objects are allocated through the SLUB fastpath.
 128  *
 129  * This should be dropped to PAGE_SIZE / 2 once the page allocator
 130  * "fastpath" becomes competitive with the slab allocator fastpaths.
 131  */
 132 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 133
 134 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 135
 136 /*
 137  * We keep the general caches in an array of slab caches that are used for
 138  * 2^x bytes of allocations.
 139  */
 140 extern struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT];
 141
 142 /*
 143  * Sorry that the following has to be that ugly but some versions of GCC
 144  * have trouble with constant propagation and loops.
 145  */
 146 static __always_inline int kmalloc_index(size_t size)
 147 {
 148         if (!size)
 149                 return 0;
 150
 151         if (size <= KMALLOC_MIN_SIZE)
 152                 return KMALLOC_SHIFT_LOW;
 153
 154 #if KMALLOC_MIN_SIZE <= 64
 155         if (size > 64 && size <= 96)
 156                 return 1;
 157         if (size > 128 && size <= 192)
 158                 return 2;
 159 #endif
 160         if (size <=          8) return 3;
 161         if (size <=         16) return 4;
 162         if (size <=         32) return 5;
 163         if (size <=         64) return 6;
 164         if (size <=        128) return 7;
 165         if (size <=        256) return 8;
 166         if (size <=        512) return 9;
 167         if (size <=       1024) return 10;
 168         if (size <=   2 * 1024) return 11;
 169         if (size <=   4 * 1024) return 12;
 170 /*
 171  * The following is only needed to support architectures with a larger page
 172  * size than 4k.
 173  */
 174         if (size <=   8 * 1024) return 13;
 175         if (size <=  16 * 1024) return 14;
 176         if (size <=  32 * 1024) return 15;
 177         if (size <=  64 * 1024) return 16;
 178         if (size <= 128 * 1024) return 17;
 179         if (size <= 256 * 1024) return 18;
 180         if (size <= 512 * 1024) return 19;
 181         if (size <= 1024 * 1024) return 20;
 182         if (size <=  2 * 1024 * 1024) return 21;
 183         return -1;
 184
 185 /*
 186  * What we really wanted to do and cannot do because of compiler issues is:
 187  *      int i;
 188  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 189  *              if (size <= (1 << i))
 190  *                      return i;
 191  */
 192 }
 193
 194 /*
 195  * Find the slab cache for a given combination of allocation flags and size.
 196  *
 197  * This ought to end up with a global pointer to the right cache
 198  * in kmalloc_caches.
 199  */
 200 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 201 {
 202         int index = kmalloc_index(size);
 203
 204         if (index == 0)
 205                 return NULL;
 206
 207         return &kmalloc_caches[index];
 208 }
 209
 210 #ifdef CONFIG_ZONE_DMA
 211 #define SLUB_DMA __GFP_DMA
 212 #else
 213 /* Disable DMA functionality */
 214 #define SLUB_DMA (__force gfp_t)0
 215 #endif
 216
 217 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 218 void *__kmalloc(size_t size, gfp_t flags);
 219
 220 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 221 {
 222         return (void *)__get_free_pages(flags | __GFP_COMP, get_order(size));
 223 }
 224
 225 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 226 {
 227         if (__builtin_constant_p(size)) {
 228                 if (size > SLUB_MAX_SIZE)
 229                         return kmalloc_large(size, flags);
 230
 231                 if (!(flags & SLUB_DMA)) {
 232                         struct kmem_cache *s = kmalloc_slab(size);
 233
 234                         if (!s)
 235                                 return ZERO_SIZE_PTR;
 236
 237                         return kmem_cache_alloc(s, flags);
 238                 }
 239         }
 240         return __kmalloc(size, flags);
 241 }
 242
 243 #ifdef CONFIG_NUMA
 244 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 245 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 246
 247 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 248 {
 249         if (__builtin_constant_p(size) &&
 250                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 251                         struct kmem_cache *s = kmalloc_slab(size);
 252
 253                 if (!s)
 254                         return ZERO_SIZE_PTR;
 255
 256                 return kmem_cache_alloc_node(s, flags, node);
 257         }
 258         return __kmalloc_node(size, flags, node);
 259 }
 260 #endif
 261
 262 #endif /* _LINUX_SLUB_DEF_H */