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         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 __percpu *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_SYSFS
  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 #endif
  99         struct kmem_cache_node *node[MAX_NUMNODES];
 100 };
 101
 102 /*
 103  * Kmalloc subsystem.
 104  */
 105 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 106 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 107 #else
 108 #define KMALLOC_MIN_SIZE 8
 109 #endif
 110
 111 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 112
 113 #ifdef ARCH_DMA_MINALIGN
 114 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
 115 #else
 116 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
 117 #endif
 118
 119 #ifndef ARCH_SLAB_MINALIGN
 120 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 121 #endif
 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 #ifdef CONFIG_ZONE_DMA
 137 #define SLUB_DMA __GFP_DMA
 138 #else
 139 /* Disable DMA functionality */
 140 #define SLUB_DMA (__force gfp_t)0
 141 #endif
 142
 143 /*
 144  * We keep the general caches in an array of slab caches that are used for
 145  * 2^x bytes of allocations.
 146  */
 147 extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 148
 149 /*
 150  * Sorry that the following has to be that ugly but some versions of GCC
 151  * have trouble with constant propagation and loops.
 152  */
 153 static __always_inline int kmalloc_index(size_t size)
 154 {
 155         if (!size)
 156                 return 0;
 157
 158         if (size <= KMALLOC_MIN_SIZE)
 159                 return KMALLOC_SHIFT_LOW;
 160
 161         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 162                 return 1;
 163         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 164                 return 2;
 165         if (size <=          8) return 3;
 166         if (size <=         16) return 4;
 167         if (size <=         32) return 5;
 168         if (size <=         64) return 6;
 169         if (size <=        128) return 7;
 170         if (size <=        256) return 8;
 171         if (size <=        512) return 9;
 172         if (size <=       1024) return 10;
 173         if (size <=   2 * 1024) return 11;
 174         if (size <=   4 * 1024) return 12;
 175 /*
 176  * The following is only needed to support architectures with a larger page
 177  * size than 4k.
 178  */
 179         if (size <=   8 * 1024) return 13;
 180         if (size <=  16 * 1024) return 14;
 181         if (size <=  32 * 1024) return 15;
 182         if (size <=  64 * 1024) return 16;
 183         if (size <= 128 * 1024) return 17;
 184         if (size <= 256 * 1024) return 18;
 185         if (size <= 512 * 1024) return 19;
 186         if (size <= 1024 * 1024) return 20;
 187         if (size <=  2 * 1024 * 1024) return 21;
 188         return -1;
 189
 190 /*
 191  * What we really wanted to do and cannot do because of compiler issues is:
 192  *      int i;
 193  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 194  *              if (size <= (1 << i))
 195  *                      return i;
 196  */
 197 }
 198
 199 /*
 200  * Find the slab cache for a given combination of allocation flags and size.
 201  *
 202  * This ought to end up with a global pointer to the right cache
 203  * in kmalloc_caches.
 204  */
 205 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 206 {
 207         int index = kmalloc_index(size);
 208
 209         if (index == 0)
 210                 return NULL;
 211
 212         return kmalloc_caches[index];
 213 }
 214
 215 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 216 void *__kmalloc(size_t size, gfp_t flags);
 217
 218 static __always_inline void *
 219 kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 220 {
 221         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 222         kmemleak_alloc(ret, size, 1, flags);
 223         return ret;
 224 }
 225
 226 #ifdef CONFIG_TRACING
 227 extern void *
 228 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 229 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 230 #else
 231 static __always_inline void *
 232 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 233 {
 234         return kmem_cache_alloc(s, gfpflags);
 235 }
 236
 237 static __always_inline void *
 238 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 239 {
 240         return kmalloc_order(size, flags, order);
 241 }
 242 #endif
 243
 244 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 245 {
 246         unsigned int order = get_order(size);
 247         return kmalloc_order_trace(size, flags, order);
 248 }
 249
 250 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 251 {
 252         if (__builtin_constant_p(size)) {
 253                 if (size > SLUB_MAX_SIZE)
 254                         return kmalloc_large(size, flags);
 255
 256                 if (!(flags & SLUB_DMA)) {
 257                         struct kmem_cache *s = kmalloc_slab(size);
 258
 259                         if (!s)
 260                                 return ZERO_SIZE_PTR;
 261
 262                         return kmem_cache_alloc_trace(s, flags, size);
 263                 }
 264         }
 265         return __kmalloc(size, flags);
 266 }
 267
 268 #ifdef CONFIG_NUMA
 269 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 270 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 271
 272 #ifdef CONFIG_TRACING
 273 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 274                                            gfp_t gfpflags,
 275                                            int node, size_t size);
 276 #else
 277 static __always_inline void *
 278 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 279                               gfp_t gfpflags,
 280                               int node, size_t size)
 281 {
 282         return kmem_cache_alloc_node(s, gfpflags, node);
 283 }
 284 #endif
 285
 286 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 287 {
 288         if (__builtin_constant_p(size) &&
 289                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 290                         struct kmem_cache *s = kmalloc_slab(size);
 291
 292                 if (!s)
 293                         return ZERO_SIZE_PTR;
 294
 295                 return kmem_cache_alloc_node_trace(s, flags, node, size);
 296         }
 297         return __kmalloc_node(size, flags, node);
 298 }
 299 #endif
 300
 301 #endif /* _LINUX_SLUB_DEF_H */