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         CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
  36         NR_SLUB_STAT_ITEMS };
  37
  38 struct kmem_cache_cpu {
  39         void **freelist;        /* Pointer to next available object */
  40         unsigned long tid;      /* Globally unique transaction id */
  41         struct page *page;      /* The slab from which we are allocating */
  42         int node;               /* The node of the page (or -1 for debug) */
  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         struct kmem_cache_cpu __percpu *cpu_slab;
  73         /* Used for retriving partial slabs etc */
  74         unsigned long flags;
  75         unsigned long min_partial;
  76         int size;               /* The size of an object including meta data */
  77         int objsize;            /* The size of an object without meta data */
  78         int offset;             /* Free pointer offset. */
  79         struct kmem_cache_order_objects oo;
  80
  81         /* Allocation and freeing of slabs */
  82         struct kmem_cache_order_objects max;
  83         struct kmem_cache_order_objects min;
  84         gfp_t allocflags;       /* gfp flags to use on each alloc */
  85         int refcount;           /* Refcount for slab cache destroy */
  86         void (*ctor)(void *);
  87         int inuse;              /* Offset to metadata */
  88         int align;              /* Alignment */
  89         int reserved;           /* Reserved bytes at the end of slabs */
  90         const char *name;       /* Name (only for display!) */
  91         struct list_head list;  /* List of slab caches */
  92 #ifdef CONFIG_SYSFS
  93         struct kobject kobj;    /* For sysfs */
  94 #endif
  95
  96 #ifdef CONFIG_NUMA
  97         /*
  98          * Defragmentation by allocating from a remote node.
  99          */
 100         int remote_node_defrag_ratio;
 101 #endif
 102         struct kmem_cache_node *node[MAX_NUMNODES];
 103 };
 104
 105 /*
 106  * Kmalloc subsystem.
 107  */
 108 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 109 #define KMALLOC_MIN_SIZE ARCH_DMA_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 #else
 132 /* Disable DMA functionality */
 133 #define SLUB_DMA (__force gfp_t)0
 134 #endif
 135
 136 /*
 137  * We keep the general caches in an array of slab caches that are used for
 138  * 2^x bytes of allocations.
 139  */
 140 extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 141
 142 /*
 143  * Sorry that the following has to be that ugly but some versions of GCC
 144  * have trouble with constant propagation and loops.
 145  */
 146 static __always_inline int kmalloc_index(size_t size)
 147 {
 148         if (!size)
 149                 return 0;
 150
 151         if (size <= KMALLOC_MIN_SIZE)
 152                 return KMALLOC_SHIFT_LOW;
 153
 154         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 155                 return 1;
 156         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 157                 return 2;
 158         if (size <=          8) return 3;
 159         if (size <=         16) return 4;
 160         if (size <=         32) return 5;
 161         if (size <=         64) return 6;
 162         if (size <=        128) return 7;
 163         if (size <=        256) return 8;
 164         if (size <=        512) return 9;
 165         if (size <=       1024) return 10;
 166         if (size <=   2 * 1024) return 11;
 167         if (size <=   4 * 1024) return 12;
 168 /*
 169  * The following is only needed to support architectures with a larger page
 170  * size than 4k. We need to support 2 * PAGE_SIZE here. So for a 64k page
 171  * size we would have to go up to 128k.
 172  */
 173         if (size <=   8 * 1024) return 13;
 174         if (size <=  16 * 1024) return 14;
 175         if (size <=  32 * 1024) return 15;
 176         if (size <=  64 * 1024) return 16;
 177         if (size <= 128 * 1024) return 17;
 178         if (size <= 256 * 1024) return 18;
 179         if (size <= 512 * 1024) return 19;
 180         if (size <= 1024 * 1024) return 20;
 181         if (size <=  2 * 1024 * 1024) return 21;
 182         BUG();
 183         return -1; /* Will never be reached */
 184
 185 /*
 186  * What we really wanted to do and cannot do because of compiler issues is:
 187  *      int i;
 188  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 189  *              if (size <= (1 << i))
 190  *                      return i;
 191  */
 192 }
 193
 194 /*
 195  * Find the slab cache for a given combination of allocation flags and size.
 196  *
 197  * This ought to end up with a global pointer to the right cache
 198  * in kmalloc_caches.
 199  */
 200 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 201 {
 202         int index = kmalloc_index(size);
 203
 204         if (index == 0)
 205                 return NULL;
 206
 207         return kmalloc_caches[index];
 208 }
 209
 210 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 211 void *__kmalloc(size_t size, gfp_t flags);
 212
 213 static __always_inline void *
 214 kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 215 {
 216         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 217         kmemleak_alloc(ret, size, 1, flags);
 218         return ret;
 219 }
 220
 221 /**
 222  * Calling this on allocated memory will check that the memory
 223  * is expected to be in use, and print warnings if not.
 224  */
 225 #ifdef CONFIG_SLUB_DEBUG
 226 extern bool verify_mem_not_deleted(const void *x);
 227 #else
 228 static inline bool verify_mem_not_deleted(const void *x)
 229 {
 230         return true;
 231 }
 232 #endif
 233
 234 #ifdef CONFIG_TRACING
 235 extern void *
 236 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 237 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 238 #else
 239 static __always_inline void *
 240 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 241 {
 242         return kmem_cache_alloc(s, gfpflags);
 243 }
 244
 245 static __always_inline void *
 246 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 247 {
 248         return kmalloc_order(size, flags, order);
 249 }
 250 #endif
 251
 252 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 253 {
 254         unsigned int order = get_order(size);
 255         return kmalloc_order_trace(size, flags, order);
 256 }
 257
 258 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 259 {
 260         if (__builtin_constant_p(size)) {
 261                 if (size > SLUB_MAX_SIZE)
 262                         return kmalloc_large(size, flags);
 263
 264                 if (!(flags & SLUB_DMA)) {
 265                         struct kmem_cache *s = kmalloc_slab(size);
 266
 267                         if (!s)
 268                                 return ZERO_SIZE_PTR;
 269
 270                         return kmem_cache_alloc_trace(s, flags, size);
 271                 }
 272         }
 273         return __kmalloc(size, flags);
 274 }
 275
 276 #ifdef CONFIG_NUMA
 277 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 278 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 279
 280 #ifdef CONFIG_TRACING
 281 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 282                                            gfp_t gfpflags,
 283                                            int node, size_t size);
 284 #else
 285 static __always_inline void *
 286 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 287                               gfp_t gfpflags,
 288                               int node, size_t size)
 289 {
 290         return kmem_cache_alloc_node(s, gfpflags, node);
 291 }
 292 #endif
 293
 294 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 295 {
 296         if (__builtin_constant_p(size) &&
 297                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 298                         struct kmem_cache *s = kmalloc_slab(size);
 299
 300                 if (!s)
 301                         return ZERO_SIZE_PTR;
 302
 303                 return kmem_cache_alloc_node_trace(s, flags, node, size);
 304         }
 305         return __kmalloc_node(size, flags, node);
 306 }
 307 #endif
 308
 309 #endif /* _LINUX_SLUB_DEF_H */