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/kmemleak.h>
  14
  15 #include <trace/events/kmem.h>
  16
  17 enum stat_item {
  18         ALLOC_FASTPATH,         /* Allocation from cpu slab */
  19         ALLOC_SLOWPATH,         /* Allocation by getting a new cpu slab */
  20         FREE_FASTPATH,          /* Free to cpu slub */
  21         FREE_SLOWPATH,          /* Freeing not to cpu slab */
  22         FREE_FROZEN,            /* Freeing to frozen slab */
  23         FREE_ADD_PARTIAL,       /* Freeing moves slab to partial list */
  24         FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
  25         ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from partial list */
  26         ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
  27         ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
  28         FREE_SLAB,              /* Slab freed to the page allocator */
  29         CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
  30         DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
  31         DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
  32         DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
  33         DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
  34         DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
  35         ORDER_FALLBACK,         /* Number of times fallback was necessary */
  36         NR_SLUB_STAT_ITEMS };
  37
  38 struct kmem_cache_cpu {
  39         void **freelist;        /* Pointer to first free per cpu object */
  40         struct page *page;      /* The slab from which we are allocating */
  41         int node;               /* The node of the page (or -1 for debug) */
  42 #ifdef CONFIG_SLUB_STATS
  43         unsigned stat[NR_SLUB_STAT_ITEMS];
  44 #endif
  45 };
  46
  47 struct kmem_cache_node {
  48         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  49         unsigned long nr_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         struct kmem_cache_cpu *cpu_slab;
  72         /* Used for retriving partial slabs etc */
  73         unsigned long flags;
  74         int size;               /* The size of an object including meta data */
  75         int objsize;            /* The size of an object without meta data */
  76         int offset;             /* Free pointer offset. */
  77         struct kmem_cache_order_objects oo;
  78
  79         /*
  80          * Avoid an extra cache line for UP, SMP and for the node local to
  81          * struct kmem_cache.
  82          */
  83         struct kmem_cache_node local_node;
  84
  85         /* Allocation and freeing of slabs */
  86         struct kmem_cache_order_objects max;
  87         struct kmem_cache_order_objects min;
  88         gfp_t allocflags;       /* gfp flags to use on each alloc */
  89         int refcount;           /* Refcount for slab cache destroy */
  90         void (*ctor)(void *);
  91         int inuse;              /* Offset to metadata */
  92         int align;              /* Alignment */
  93         unsigned long min_partial;
  94         const char *name;       /* Name (only for display!) */
  95         struct list_head list;  /* List of slab caches */
  96 #ifdef CONFIG_SLUB_DEBUG
  97         struct kobject kobj;    /* For sysfs */
  98 #endif
  99
 100 #ifdef CONFIG_NUMA
 101         /*
 102          * Defragmentation by allocating from a remote node.
 103          */
 104         int remote_node_defrag_ratio;
 105         struct kmem_cache_node *node[MAX_NUMNODES];
 106 #endif
 107 };
 108
 109 /*
 110  * Kmalloc subsystem.
 111  */
 112 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
 113 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
 114 #else
 115 #define KMALLOC_MIN_SIZE 8
 116 #endif
 117
 118 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 119
 120 #ifndef ARCH_KMALLOC_MINALIGN
 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 /* Reserve extra caches for potential DMA use */
 144 #define KMALLOC_CACHES (2 * SLUB_PAGE_SHIFT - 6)
 145 #else
 146 /* Disable DMA functionality */
 147 #define SLUB_DMA (__force gfp_t)0
 148 #define KMALLOC_CACHES SLUB_PAGE_SHIFT
 149 #endif
 150
 151 /*
 152  * We keep the general caches in an array of slab caches that are used for
 153  * 2^x bytes of allocations.
 154  */
 155 extern struct kmem_cache kmalloc_caches[KMALLOC_CACHES];
 156
 157 /*
 158  * Sorry that the following has to be that ugly but some versions of GCC
 159  * have trouble with constant propagation and loops.
 160  */
 161 static __always_inline int kmalloc_index(size_t size)
 162 {
 163         if (!size)
 164                 return 0;
 165
 166         if (size <= KMALLOC_MIN_SIZE)
 167                 return KMALLOC_SHIFT_LOW;
 168
 169         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 170                 return 1;
 171         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 172                 return 2;
 173         if (size <=          8) return 3;
 174         if (size <=         16) return 4;
 175         if (size <=         32) return 5;
 176         if (size <=         64) return 6;
 177         if (size <=        128) return 7;
 178         if (size <=        256) return 8;
 179         if (size <=        512) return 9;
 180         if (size <=       1024) return 10;
 181         if (size <=   2 * 1024) return 11;
 182         if (size <=   4 * 1024) return 12;
 183 /*
 184  * The following is only needed to support architectures with a larger page
 185  * size than 4k.
 186  */
 187         if (size <=   8 * 1024) return 13;
 188         if (size <=  16 * 1024) return 14;
 189         if (size <=  32 * 1024) return 15;
 190         if (size <=  64 * 1024) return 16;
 191         if (size <= 128 * 1024) return 17;
 192         if (size <= 256 * 1024) return 18;
 193         if (size <= 512 * 1024) return 19;
 194         if (size <= 1024 * 1024) return 20;
 195         if (size <=  2 * 1024 * 1024) return 21;
 196         return -1;
 197
 198 /*
 199  * What we really wanted to do and cannot do because of compiler issues is:
 200  *      int i;
 201  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 202  *              if (size <= (1 << i))
 203  *                      return i;
 204  */
 205 }
 206
 207 /*
 208  * Find the slab cache for a given combination of allocation flags and size.
 209  *
 210  * This ought to end up with a global pointer to the right cache
 211  * in kmalloc_caches.
 212  */
 213 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 214 {
 215         int index = kmalloc_index(size);
 216
 217         if (index == 0)
 218                 return NULL;
 219
 220         return &kmalloc_caches[index];
 221 }
 222
 223 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 224 void *__kmalloc(size_t size, gfp_t flags);
 225
 226 #ifdef CONFIG_TRACING
 227 extern void *kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags);
 228 #else
 229 static __always_inline void *
 230 kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags)
 231 {
 232         return kmem_cache_alloc(s, gfpflags);
 233 }
 234 #endif
 235
 236 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 237 {
 238         unsigned int order = get_order(size);
 239         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 240
 241         kmemleak_alloc(ret, size, 1, flags);
 242         trace_kmalloc(_THIS_IP_, ret, size, PAGE_SIZE << order, flags);
 243
 244         return ret;
 245 }
 246
 247 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 248 {
 249         void *ret;
 250
 251         if (__builtin_constant_p(size)) {
 252                 if (size > SLUB_MAX_SIZE)
 253                         return kmalloc_large(size, flags);
 254
 255                 if (!(flags & SLUB_DMA)) {
 256                         struct kmem_cache *s = kmalloc_slab(size);
 257
 258                         if (!s)
 259                                 return ZERO_SIZE_PTR;
 260
 261                         ret = kmem_cache_alloc_notrace(s, flags);
 262
 263                         trace_kmalloc(_THIS_IP_, ret, size, s->size, flags);
 264
 265                         return ret;
 266                 }
 267         }
 268         return __kmalloc(size, flags);
 269 }
 270
 271 #ifdef CONFIG_NUMA
 272 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 273 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 274
 275 #ifdef CONFIG_TRACING
 276 extern void *kmem_cache_alloc_node_notrace(struct kmem_cache *s,
 277                                            gfp_t gfpflags,
 278                                            int node);
 279 #else
 280 static __always_inline void *
 281 kmem_cache_alloc_node_notrace(struct kmem_cache *s,
 282                               gfp_t gfpflags,
 283                               int node)
 284 {
 285         return kmem_cache_alloc_node(s, gfpflags, node);
 286 }
 287 #endif
 288
 289 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 290 {
 291         void *ret;
 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                 ret = kmem_cache_alloc_node_notrace(s, flags, node);
 301
 302                 trace_kmalloc_node(_THIS_IP_, ret,
 303                                    size, s->size, flags, node);
 304
 305                 return ret;
 306         }
 307         return __kmalloc_node(size, flags, node);
 308 }
 309 #endif
 310
 311 #endif /* _LINUX_SLUB_DEF_H */