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 #include <linux/kmemleak.h>
  15
  16 enum stat_item {
  17         ALLOC_FASTPATH,         /* Allocation from cpu slab */
  18         ALLOC_SLOWPATH,         /* Allocation by getting a new cpu slab */
  19         FREE_FASTPATH,          /* Free to cpu slub */
  20         FREE_SLOWPATH,          /* Freeing not to cpu slab */
  21         FREE_FROZEN,            /* Freeing to frozen slab */
  22         FREE_ADD_PARTIAL,       /* Freeing moves slab to partial list */
  23         FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
  24         ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from partial list */
  25         ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
  26         ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
  27         FREE_SLAB,              /* Slab freed to the page allocator */
  28         CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
  29         DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
  30         DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
  31         DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
  32         DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
  33         DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
  34         ORDER_FALLBACK,         /* Number of times fallback was necessary */
  35         CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
  36         NR_SLUB_STAT_ITEMS };
  37
  38 struct kmem_cache_cpu {
  39         void **freelist;        /* Pointer to next available object */
  40 #ifdef CONFIG_CMPXCHG_LOCAL
  41         unsigned long tid;      /* Globally unique transaction id */
  42 #endif
  43         struct page *page;      /* The slab from which we are allocating */
  44         int node;               /* The node of the page (or -1 for debug) */
  45 #ifdef CONFIG_SLUB_STATS
  46         unsigned stat[NR_SLUB_STAT_ITEMS];
  47 #endif
  48 };
  49
  50 struct kmem_cache_node {
  51         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  52         unsigned long nr_partial;
  53         struct list_head partial;
  54 #ifdef CONFIG_SLUB_DEBUG
  55         atomic_long_t nr_slabs;
  56         atomic_long_t total_objects;
  57         struct list_head full;
  58 #endif
  59 };
  60
  61 /*
  62  * Word size structure that can be atomically updated or read and that
  63  * contains both the order and the number of objects that a slab of the
  64  * given order would contain.
  65  */
  66 struct kmem_cache_order_objects {
  67         unsigned long x;
  68 };
  69
  70 /*
  71  * Slab cache management.
  72  */
  73 struct kmem_cache {
  74         struct kmem_cache_cpu __percpu *cpu_slab;
  75         /* Used for retriving partial slabs etc */
  76         unsigned long flags;
  77         unsigned long min_partial;
  78         int size;               /* The size of an object including meta data */
  79         int objsize;            /* The size of an object without meta data */
  80         int offset;             /* Free pointer offset. */
  81         struct kmem_cache_order_objects oo;
  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         int reserved;           /* Reserved bytes at the end of slabs */
  92         const char *name;       /* Name (only for display!) */
  93         struct list_head list;  /* List of slab caches */
  94 #ifdef CONFIG_SYSFS
  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 #endif
 104         struct kmem_cache_node *node[MAX_NUMNODES];
 105 };
 106
 107 /*
 108  * Kmalloc subsystem.
 109  */
 110 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 111 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 112 #else
 113 #define KMALLOC_MIN_SIZE 8
 114 #endif
 115
 116 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 117
 118 #ifdef ARCH_DMA_MINALIGN
 119 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
 120 #else
 121 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
 122 #endif
 123
 124 #ifndef ARCH_SLAB_MINALIGN
 125 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 126 #endif
 127
 128 /*
 129  * Maximum kmalloc object size handled by SLUB. Larger object allocations
 130  * are passed through to the page allocator. The page allocator "fastpath"
 131  * is relatively slow so we need this value sufficiently high so that
 132  * performance critical objects are allocated through the SLUB fastpath.
 133  *
 134  * This should be dropped to PAGE_SIZE / 2 once the page allocator
 135  * "fastpath" becomes competitive with the slab allocator fastpaths.
 136  */
 137 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 138
 139 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 140
 141 #ifdef CONFIG_ZONE_DMA
 142 #define SLUB_DMA __GFP_DMA
 143 #else
 144 /* Disable DMA functionality */
 145 #define SLUB_DMA (__force gfp_t)0
 146 #endif
 147
 148 /*
 149  * We keep the general caches in an array of slab caches that are used for
 150  * 2^x bytes of allocations.
 151  */
 152 extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 153
 154 /*
 155  * Sorry that the following has to be that ugly but some versions of GCC
 156  * have trouble with constant propagation and loops.
 157  */
 158 static __always_inline int kmalloc_index(size_t size)
 159 {
 160         if (!size)
 161                 return 0;
 162
 163         if (size <= KMALLOC_MIN_SIZE)
 164                 return KMALLOC_SHIFT_LOW;
 165
 166         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 167                 return 1;
 168         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 169                 return 2;
 170         if (size <=          8) return 3;
 171         if (size <=         16) return 4;
 172         if (size <=         32) return 5;
 173         if (size <=         64) return 6;
 174         if (size <=        128) return 7;
 175         if (size <=        256) return 8;
 176         if (size <=        512) return 9;
 177         if (size <=       1024) return 10;
 178         if (size <=   2 * 1024) return 11;
 179         if (size <=   4 * 1024) return 12;
 180 /*
 181  * The following is only needed to support architectures with a larger page
 182  * size than 4k.
 183  */
 184         if (size <=   8 * 1024) return 13;
 185         if (size <=  16 * 1024) return 14;
 186         if (size <=  32 * 1024) return 15;
 187         if (size <=  64 * 1024) return 16;
 188         if (size <= 128 * 1024) return 17;
 189         if (size <= 256 * 1024) return 18;
 190         if (size <= 512 * 1024) return 19;
 191         if (size <= 1024 * 1024) return 20;
 192         if (size <=  2 * 1024 * 1024) return 21;
 193         return -1;
 194
 195 /*
 196  * What we really wanted to do and cannot do because of compiler issues is:
 197  *      int i;
 198  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 199  *              if (size <= (1 << i))
 200  *                      return i;
 201  */
 202 }
 203
 204 /*
 205  * Find the slab cache for a given combination of allocation flags and size.
 206  *
 207  * This ought to end up with a global pointer to the right cache
 208  * in kmalloc_caches.
 209  */
 210 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 211 {
 212         int index = kmalloc_index(size);
 213
 214         if (index == 0)
 215                 return NULL;
 216
 217         return kmalloc_caches[index];
 218 }
 219
 220 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 221 void *__kmalloc(size_t size, gfp_t flags);
 222
 223 static __always_inline void *
 224 kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 225 {
 226         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 227         kmemleak_alloc(ret, size, 1, flags);
 228         return ret;
 229 }
 230
 231 #ifdef CONFIG_TRACING
 232 extern void *
 233 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 234 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 235 #else
 236 static __always_inline void *
 237 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 238 {
 239         return kmem_cache_alloc(s, gfpflags);
 240 }
 241
 242 static __always_inline void *
 243 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 244 {
 245         return kmalloc_order(size, flags, order);
 246 }
 247 #endif
 248
 249 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 250 {
 251         unsigned int order = get_order(size);
 252         return kmalloc_order_trace(size, flags, order);
 253 }
 254
 255 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 256 {
 257         if (__builtin_constant_p(size)) {
 258                 if (size > SLUB_MAX_SIZE)
 259                         return kmalloc_large(size, flags);
 260
 261                 if (!(flags & SLUB_DMA)) {
 262                         struct kmem_cache *s = kmalloc_slab(size);
 263
 264                         if (!s)
 265                                 return ZERO_SIZE_PTR;
 266
 267                         return kmem_cache_alloc_trace(s, flags, size);
 268                 }
 269         }
 270         return __kmalloc(size, flags);
 271 }
 272
 273 #ifdef CONFIG_NUMA
 274 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 275 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 276
 277 #ifdef CONFIG_TRACING
 278 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 279                                            gfp_t gfpflags,
 280                                            int node, size_t size);
 281 #else
 282 static __always_inline void *
 283 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 284                               gfp_t gfpflags,
 285                               int node, size_t size)
 286 {
 287         return kmem_cache_alloc_node(s, gfpflags, node);
 288 }
 289 #endif
 290
 291 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 292 {
 293         if (__builtin_constant_p(size) &&
 294                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 295                         struct kmem_cache *s = kmalloc_slab(size);
 296
 297                 if (!s)
 298                         return ZERO_SIZE_PTR;
 299
 300                 return kmem_cache_alloc_node_trace(s, flags, node, size);
 301         }
 302         return __kmalloc_node(size, flags, node);
 303 }
 304 #endif
 305
 306 #endif /* _LINUX_SLUB_DEF_H */