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