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         unsigned int offset;    /* Freepointer offset (in word units) */
  42         unsigned int objsize;   /* Size of an object (from kmem_cache) */
  43 #ifdef CONFIG_SLUB_STATS
  44         unsigned stat[NR_SLUB_STAT_ITEMS];
  45 #endif
  46 };
  47
  48 struct kmem_cache_node {
  49         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  50         unsigned long nr_partial;
  51         struct list_head partial;
  52 #ifdef CONFIG_SLUB_DEBUG
  53         atomic_long_t nr_slabs;
  54         atomic_long_t total_objects;
  55         struct list_head full;
  56 #endif
  57 };
  58
  59 /*
  60  * Word size structure that can be atomically updated or read and that
  61  * contains both the order and the number of objects that a slab of the
  62  * given order would contain.
  63  */
  64 struct kmem_cache_order_objects {
  65         unsigned long x;
  66 };
  67
  68 /*
  69  * Slab cache management.
  70  */
  71 struct kmem_cache {
  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 #ifdef CONFIG_SMP
 108         struct kmem_cache_cpu *cpu_slab[NR_CPUS];
 109 #else
 110         struct kmem_cache_cpu cpu_slab;
 111 #endif
 112 };
 113
 114 /*
 115  * Kmalloc subsystem.
 116  */
 117 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
 118 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
 119 #else
 120 #define KMALLOC_MIN_SIZE 8
 121 #endif
 122
 123 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 124
 125 /*
 126  * Maximum kmalloc object size handled by SLUB. Larger object allocations
 127  * are passed through to the page allocator. The page allocator "fastpath"
 128  * is relatively slow so we need this value sufficiently high so that
 129  * performance critical objects are allocated through the SLUB fastpath.
 130  *
 131  * This should be dropped to PAGE_SIZE / 2 once the page allocator
 132  * "fastpath" becomes competitive with the slab allocator fastpaths.
 133  */
 134 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 135
 136 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 137
 138 /*
 139  * We keep the general caches in an array of slab caches that are used for
 140  * 2^x bytes of allocations.
 141  */
 142 extern struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT];
 143
 144 /*
 145  * Sorry that the following has to be that ugly but some versions of GCC
 146  * have trouble with constant propagation and loops.
 147  */
 148 static __always_inline int kmalloc_index(size_t size)
 149 {
 150         if (!size)
 151                 return 0;
 152
 153         if (size <= KMALLOC_MIN_SIZE)
 154                 return KMALLOC_SHIFT_LOW;
 155
 156 #if KMALLOC_MIN_SIZE <= 64
 157         if (size > 64 && size <= 96)
 158                 return 1;
 159         if (size > 128 && size <= 192)
 160                 return 2;
 161 #endif
 162         if (size <=          8) return 3;
 163         if (size <=         16) return 4;
 164         if (size <=         32) return 5;
 165         if (size <=         64) return 6;
 166         if (size <=        128) return 7;
 167         if (size <=        256) return 8;
 168         if (size <=        512) return 9;
 169         if (size <=       1024) return 10;
 170         if (size <=   2 * 1024) return 11;
 171         if (size <=   4 * 1024) return 12;
 172 /*
 173  * The following is only needed to support architectures with a larger page
 174  * size than 4k.
 175  */
 176         if (size <=   8 * 1024) return 13;
 177         if (size <=  16 * 1024) return 14;
 178         if (size <=  32 * 1024) return 15;
 179         if (size <=  64 * 1024) return 16;
 180         if (size <= 128 * 1024) return 17;
 181         if (size <= 256 * 1024) return 18;
 182         if (size <= 512 * 1024) return 19;
 183         if (size <= 1024 * 1024) return 20;
 184         if (size <=  2 * 1024 * 1024) return 21;
 185         return -1;
 186
 187 /*
 188  * What we really wanted to do and cannot do because of compiler issues is:
 189  *      int i;
 190  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 191  *              if (size <= (1 << i))
 192  *                      return i;
 193  */
 194 }
 195
 196 /*
 197  * Find the slab cache for a given combination of allocation flags and size.
 198  *
 199  * This ought to end up with a global pointer to the right cache
 200  * in kmalloc_caches.
 201  */
 202 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 203 {
 204         int index = kmalloc_index(size);
 205
 206         if (index == 0)
 207                 return NULL;
 208
 209         return &kmalloc_caches[index];
 210 }
 211
 212 #ifdef CONFIG_ZONE_DMA
 213 #define SLUB_DMA __GFP_DMA
 214 #else
 215 /* Disable DMA functionality */
 216 #define SLUB_DMA (__force gfp_t)0
 217 #endif
 218
 219 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 220 void *__kmalloc(size_t size, gfp_t flags);
 221
 222 #ifdef CONFIG_KMEMTRACE
 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_KMEMTRACE
 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 void __init kmem_cache_init_late(void);
 308
 309 #endif /* _LINUX_SLUB_DEF_H */