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 #include <linux/kmemtrace.h>
  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         NR_SLUB_STAT_ITEMS };
  36
  37 struct kmem_cache_cpu {
  38         void **freelist;        /* Pointer to first free per cpu object */
  39         struct page *page;      /* The slab from which we are allocating */
  40         int node;               /* The node of the page (or -1 for debug) */
  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         struct kmem_cache_cpu *cpu_slab;
  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         /* Allocation and freeing of slabs */
  79         struct kmem_cache_order_objects max;
  80         struct kmem_cache_order_objects min;
  81         gfp_t allocflags;       /* gfp flags to use on each alloc */
  82         int refcount;           /* Refcount for slab cache destroy */
  83         void (*ctor)(void *);
  84         int inuse;              /* Offset to metadata */
  85         int align;              /* Alignment */
  86         unsigned long min_partial;
  87         const char *name;       /* Name (only for display!) */
  88         struct list_head list;  /* List of slab caches */
  89 #ifdef CONFIG_SLUB_DEBUG
  90         struct kobject kobj;    /* For sysfs */
  91 #endif
  92
  93 #ifdef CONFIG_NUMA
  94         /*
  95          * Defragmentation by allocating from a remote node.
  96          */
  97         int remote_node_defrag_ratio;
  98         struct kmem_cache_node *node[MAX_NUMNODES];
  99 #else
 100         /* Avoid an extra cache line for UP */
 101         struct kmem_cache_node local_node;
 102 #endif
 103 };
 104
 105 /*
 106  * Kmalloc subsystem.
 107  */
 108 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
 109 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
 110 #else
 111 #define KMALLOC_MIN_SIZE 8
 112 #endif
 113
 114 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 115
 116 #ifndef ARCH_KMALLOC_MINALIGN
 117 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
 118 #endif
 119
 120 #ifndef ARCH_SLAB_MINALIGN
 121 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 122 #endif
 123
 124 /*
 125  * Maximum kmalloc object size handled by SLUB. Larger object allocations
 126  * are passed through to the page allocator. The page allocator "fastpath"
 127  * is relatively slow so we need this value sufficiently high so that
 128  * performance critical objects are allocated through the SLUB fastpath.
 129  *
 130  * This should be dropped to PAGE_SIZE / 2 once the page allocator
 131  * "fastpath" becomes competitive with the slab allocator fastpaths.
 132  */
 133 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 134
 135 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 136
 137 #ifdef CONFIG_ZONE_DMA
 138 #define SLUB_DMA __GFP_DMA
 139 /* Reserve extra caches for potential DMA use */
 140 #define KMALLOC_CACHES (2 * SLUB_PAGE_SHIFT)
 141 #else
 142 /* Disable DMA functionality */
 143 #define SLUB_DMA (__force gfp_t)0
 144 #define KMALLOC_CACHES SLUB_PAGE_SHIFT
 145 #endif
 146
 147 /*
 148  * We keep the general caches in an array of slab caches that are used for
 149  * 2^x bytes of allocations.
 150  */
 151 extern struct kmem_cache kmalloc_caches[KMALLOC_CACHES];
 152
 153 /*
 154  * Sorry that the following has to be that ugly but some versions of GCC
 155  * have trouble with constant propagation and loops.
 156  */
 157 static __always_inline int kmalloc_index(size_t size)
 158 {
 159         if (!size)
 160                 return 0;
 161
 162         if (size <= KMALLOC_MIN_SIZE)
 163                 return KMALLOC_SHIFT_LOW;
 164
 165         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 166                 return 1;
 167         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 168                 return 2;
 169         if (size <=          8) return 3;
 170         if (size <=         16) return 4;
 171         if (size <=         32) return 5;
 172         if (size <=         64) return 6;
 173         if (size <=        128) return 7;
 174         if (size <=        256) return 8;
 175         if (size <=        512) return 9;
 176         if (size <=       1024) return 10;
 177         if (size <=   2 * 1024) return 11;
 178         if (size <=   4 * 1024) return 12;
 179 /*
 180  * The following is only needed to support architectures with a larger page
 181  * size than 4k.
 182  */
 183         if (size <=   8 * 1024) return 13;
 184         if (size <=  16 * 1024) return 14;
 185         if (size <=  32 * 1024) return 15;
 186         if (size <=  64 * 1024) return 16;
 187         if (size <= 128 * 1024) return 17;
 188         if (size <= 256 * 1024) return 18;
 189         if (size <= 512 * 1024) return 19;
 190         if (size <= 1024 * 1024) return 20;
 191         if (size <=  2 * 1024 * 1024) return 21;
 192         return -1;
 193
 194 /*
 195  * What we really wanted to do and cannot do because of compiler issues is:
 196  *      int i;
 197  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 198  *              if (size <= (1 << i))
 199  *                      return i;
 200  */
 201 }
 202
 203 /*
 204  * Find the slab cache for a given combination of allocation flags and size.
 205  *
 206  * This ought to end up with a global pointer to the right cache
 207  * in kmalloc_caches.
 208  */
 209 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 210 {
 211         int index = kmalloc_index(size);
 212
 213         if (index == 0)
 214                 return NULL;
 215
 216         return &kmalloc_caches[index];
 217 }
 218
 219 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 220 void *__kmalloc(size_t size, gfp_t flags);
 221
 222 #ifdef CONFIG_TRACING
 223 extern void *kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags);
 224 #else
 225 static __always_inline void *
 226 kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags)
 227 {
 228         return kmem_cache_alloc(s, gfpflags);
 229 }
 230 #endif
 231
 232 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 233 {
 234         unsigned int order = get_order(size);
 235         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 236
 237         kmemleak_alloc(ret, size, 1, flags);
 238         trace_kmalloc(_THIS_IP_, ret, size, PAGE_SIZE << order, flags);
 239
 240         return ret;
 241 }
 242
 243 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 244 {
 245         void *ret;
 246
 247         if (__builtin_constant_p(size)) {
 248                 if (size > SLUB_MAX_SIZE)
 249                         return kmalloc_large(size, flags);
 250
 251                 if (!(flags & SLUB_DMA)) {
 252                         struct kmem_cache *s = kmalloc_slab(size);
 253
 254                         if (!s)
 255                                 return ZERO_SIZE_PTR;
 256
 257                         ret = kmem_cache_alloc_notrace(s, flags);
 258
 259                         trace_kmalloc(_THIS_IP_, ret, size, s->size, flags);
 260
 261                         return ret;
 262                 }
 263         }
 264         return __kmalloc(size, flags);
 265 }
 266
 267 #ifdef CONFIG_NUMA
 268 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 269 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 270
 271 #ifdef CONFIG_TRACING
 272 extern void *kmem_cache_alloc_node_notrace(struct kmem_cache *s,
 273                                            gfp_t gfpflags,
 274                                            int node);
 275 #else
 276 static __always_inline void *
 277 kmem_cache_alloc_node_notrace(struct kmem_cache *s,
 278                               gfp_t gfpflags,
 279                               int node)
 280 {
 281         return kmem_cache_alloc_node(s, gfpflags, node);
 282 }
 283 #endif
 284
 285 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 286 {
 287         void *ret;
 288
 289         if (__builtin_constant_p(size) &&
 290                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 291                         struct kmem_cache *s = kmalloc_slab(size);
 292
 293                 if (!s)
 294                         return ZERO_SIZE_PTR;
 295
 296                 ret = kmem_cache_alloc_node_notrace(s, flags, node);
 297
 298                 trace_kmalloc_node(_THIS_IP_, ret,
 299                                    size, s->size, flags, node);
 300
 301                 return ret;
 302         }
 303         return __kmalloc_node(size, flags, node);
 304 }
 305 #endif
 306
 307 #endif /* _LINUX_SLUB_DEF_H */