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