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 __percpu *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         /* Allocation and freeing of slabs */
  80         struct kmem_cache_order_objects max;
  81         struct kmem_cache_order_objects min;
  82         gfp_t allocflags;       /* gfp flags to use on each alloc */
  83         int refcount;           /* Refcount for slab cache destroy */
  84         void (*ctor)(void *);
  85         int inuse;              /* Offset to metadata */
  86         int align;              /* Alignment */
  87         unsigned long min_partial;
  88         const char *name;       /* Name (only for display!) */
  89         struct list_head list;  /* List of slab caches */
  90 #ifdef CONFIG_SLUB_DEBUG
  91         struct kobject kobj;    /* For sysfs */
  92 #endif
  93
  94 #ifdef CONFIG_NUMA
  95         /*
  96          * Defragmentation by allocating from a remote node.
  97          */
  98         int remote_node_defrag_ratio;
  99         struct kmem_cache_node *node[MAX_NUMNODES];
 100 #else
 101         /* Avoid an extra cache line for UP */
 102         struct kmem_cache_node local_node;
 103 #endif
 104 };
 105
 106 /*
 107  * Kmalloc subsystem.
 108  */
 109 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 110 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 111 #else
 112 #define KMALLOC_MIN_SIZE 8
 113 #endif
 114
 115 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 116
 117 #ifdef ARCH_DMA_MINALIGN
 118 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
 119 #else
 120 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
 121 #endif
 122
 123 #ifndef ARCH_SLAB_MINALIGN
 124 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 125 #endif
 126
 127 /*
 128  * Maximum kmalloc object size handled by SLUB. Larger object allocations
 129  * are passed through to the page allocator. The page allocator "fastpath"
 130  * is relatively slow so we need this value sufficiently high so that
 131  * performance critical objects are allocated through the SLUB fastpath.
 132  *
 133  * This should be dropped to PAGE_SIZE / 2 once the page allocator
 134  * "fastpath" becomes competitive with the slab allocator fastpaths.
 135  */
 136 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 137
 138 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 139
 140 #ifdef CONFIG_ZONE_DMA
 141 #define SLUB_DMA __GFP_DMA
 142 /* Reserve extra caches for potential DMA use */
 143 #define KMALLOC_CACHES (2 * SLUB_PAGE_SHIFT)
 144 #else
 145 /* Disable DMA functionality */
 146 #define SLUB_DMA (__force gfp_t)0
 147 #define KMALLOC_CACHES SLUB_PAGE_SHIFT
 148 #endif
 149
 150 /*
 151  * We keep the general caches in an array of slab caches that are used for
 152  * 2^x bytes of allocations.
 153  */
 154 extern struct kmem_cache kmalloc_caches[KMALLOC_CACHES];
 155
 156 /*
 157  * Sorry that the following has to be that ugly but some versions of GCC
 158  * have trouble with constant propagation and loops.
 159  */
 160 static __always_inline int kmalloc_index(size_t size)
 161 {
 162         if (!size)
 163                 return 0;
 164
 165         if (size <= KMALLOC_MIN_SIZE)
 166                 return KMALLOC_SHIFT_LOW;
 167
 168         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 169                 return 1;
 170         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 171                 return 2;
 172         if (size <=          8) return 3;
 173         if (size <=         16) return 4;
 174         if (size <=         32) return 5;
 175         if (size <=         64) return 6;
 176         if (size <=        128) return 7;
 177         if (size <=        256) return 8;
 178         if (size <=        512) return 9;
 179         if (size <=       1024) return 10;
 180         if (size <=   2 * 1024) return 11;
 181         if (size <=   4 * 1024) return 12;
 182 /*
 183  * The following is only needed to support architectures with a larger page
 184  * size than 4k.
 185  */
 186         if (size <=   8 * 1024) return 13;
 187         if (size <=  16 * 1024) return 14;
 188         if (size <=  32 * 1024) return 15;
 189         if (size <=  64 * 1024) return 16;
 190         if (size <= 128 * 1024) return 17;
 191         if (size <= 256 * 1024) return 18;
 192         if (size <= 512 * 1024) return 19;
 193         if (size <= 1024 * 1024) return 20;
 194         if (size <=  2 * 1024 * 1024) return 21;
 195         return -1;
 196
 197 /*
 198  * What we really wanted to do and cannot do because of compiler issues is:
 199  *      int i;
 200  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 201  *              if (size <= (1 << i))
 202  *                      return i;
 203  */
 204 }
 205
 206 /*
 207  * Find the slab cache for a given combination of allocation flags and size.
 208  *
 209  * This ought to end up with a global pointer to the right cache
 210  * in kmalloc_caches.
 211  */
 212 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 213 {
 214         int index = kmalloc_index(size);
 215
 216         if (index == 0)
 217                 return NULL;
 218
 219         return &kmalloc_caches[index];
 220 }
 221
 222 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 223 void *__kmalloc(size_t size, gfp_t flags);
 224
 225 #ifdef CONFIG_TRACING
 226 extern void *kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags);
 227 #else
 228 static __always_inline void *
 229 kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags)
 230 {
 231         return kmem_cache_alloc(s, gfpflags);
 232 }
 233 #endif
 234
 235 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 236 {
 237         unsigned int order = get_order(size);
 238         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 239
 240         kmemleak_alloc(ret, size, 1, flags);
 241         trace_kmalloc(_THIS_IP_, ret, size, PAGE_SIZE << order, flags);
 242
 243         return ret;
 244 }
 245
 246 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 247 {
 248         void *ret;
 249
 250         if (__builtin_constant_p(size)) {
 251                 if (size > SLUB_MAX_SIZE)
 252                         return kmalloc_large(size, flags);
 253
 254                 if (!(flags & SLUB_DMA)) {
 255                         struct kmem_cache *s = kmalloc_slab(size);
 256
 257                         if (!s)
 258                                 return ZERO_SIZE_PTR;
 259
 260                         ret = kmem_cache_alloc_notrace(s, flags);
 261
 262                         trace_kmalloc(_THIS_IP_, ret, size, s->size, flags);
 263
 264                         return ret;
 265                 }
 266         }
 267         return __kmalloc(size, flags);
 268 }
 269
 270 #ifdef CONFIG_NUMA
 271 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 272 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 273
 274 #ifdef CONFIG_TRACING
 275 extern void *kmem_cache_alloc_node_notrace(struct kmem_cache *s,
 276                                            gfp_t gfpflags,
 277                                            int node);
 278 #else
 279 static __always_inline void *
 280 kmem_cache_alloc_node_notrace(struct kmem_cache *s,
 281                               gfp_t gfpflags,
 282                               int node)
 283 {
 284         return kmem_cache_alloc_node(s, gfpflags, node);
 285 }
 286 #endif
 287
 288 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 289 {
 290         void *ret;
 291
 292         if (__builtin_constant_p(size) &&
 293                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 294                         struct kmem_cache *s = kmalloc_slab(size);
 295
 296                 if (!s)
 297                         return ZERO_SIZE_PTR;
 298
 299                 ret = kmem_cache_alloc_node_notrace(s, flags, node);
 300
 301                 trace_kmalloc_node(_THIS_IP_, ret,
 302                                    size, s->size, flags, node);
 303
 304                 return ret;
 305         }
 306         return __kmalloc_node(size, flags, node);
 307 }
 308 #endif
 309
 310 #endif /* _LINUX_SLUB_DEF_H */