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/bug.h>
  12 #include <linux/workqueue.h>
  13 #include <linux/kobject.h>
  14
  15 #include <linux/kmemleak.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 node partial list */
  26         ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
  27         ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
  28         ALLOC_NODE_MISMATCH,    /* Switching cpu slab */
  29         FREE_SLAB,              /* Slab freed to the page allocator */
  30         CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
  31         DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
  32         DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
  33         DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
  34         DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
  35         DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
  36         DEACTIVATE_BYPASS,      /* Implicit deactivation */
  37         ORDER_FALLBACK,         /* Number of times fallback was necessary */
  38         CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
  39         CMPXCHG_DOUBLE_FAIL,    /* Number of times that cmpxchg double did not match */
  40         CPU_PARTIAL_ALLOC,      /* Used cpu partial on alloc */
  41         CPU_PARTIAL_FREE,       /* Refill cpu partial on free */
  42         CPU_PARTIAL_NODE,       /* Refill cpu partial from node partial */
  43         CPU_PARTIAL_DRAIN,      /* Drain cpu partial to node partial */
  44         NR_SLUB_STAT_ITEMS };
  45
  46 struct kmem_cache_cpu {
  47         void **freelist;        /* Pointer to next available object */
  48         unsigned long tid;      /* Globally unique transaction id */
  49         struct page *page;      /* The slab from which we are allocating */
  50         struct page *partial;   /* Partially allocated frozen slabs */
  51 #ifdef CONFIG_SLUB_STATS
  52         unsigned stat[NR_SLUB_STAT_ITEMS];
  53 #endif
  54 };
  55
  56 struct kmem_cache_node {
  57         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  58         unsigned long nr_partial;
  59         struct list_head partial;
  60 #ifdef CONFIG_SLUB_DEBUG
  61         atomic_long_t nr_slabs;
  62         atomic_long_t total_objects;
  63         struct list_head full;
  64 #endif
  65 };
  66
  67 /*
  68  * Word size structure that can be atomically updated or read and that
  69  * contains both the order and the number of objects that a slab of the
  70  * given order would contain.
  71  */
  72 struct kmem_cache_order_objects {
  73         unsigned long x;
  74 };
  75
  76 /*
  77  * Slab cache management.
  78  */
  79 struct kmem_cache {
  80         struct kmem_cache_cpu __percpu *cpu_slab;
  81         /* Used for retriving partial slabs etc */
  82         unsigned long flags;
  83         unsigned long min_partial;
  84         int size;               /* The size of an object including meta data */
  85         int object_size;        /* The size of an object without meta data */
  86         int offset;             /* Free pointer offset. */
  87         int cpu_partial;        /* Number of per cpu partial objects to keep around */
  88         struct kmem_cache_order_objects oo;
  89
  90         /* Allocation and freeing of slabs */
  91         struct kmem_cache_order_objects max;
  92         struct kmem_cache_order_objects min;
  93         gfp_t allocflags;       /* gfp flags to use on each alloc */
  94         int refcount;           /* Refcount for slab cache destroy */
  95         void (*ctor)(void *);
  96         int inuse;              /* Offset to metadata */
  97         int align;              /* Alignment */
  98         int reserved;           /* Reserved bytes at the end of slabs */
  99         const char *name;       /* Name (only for display!) */
 100         struct list_head list;  /* List of slab caches */
 101 #ifdef CONFIG_SYSFS
 102         struct kobject kobj;    /* For sysfs */
 103 #endif
 104
 105 #ifdef CONFIG_NUMA
 106         /*
 107          * Defragmentation by allocating from a remote node.
 108          */
 109         int remote_node_defrag_ratio;
 110 #endif
 111         struct kmem_cache_node *node[MAX_NUMNODES];
 112 };
 113
 114 /*
 115  * Kmalloc subsystem.
 116  */
 117 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 118 #define KMALLOC_MIN_SIZE ARCH_DMA_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 #ifdef CONFIG_ZONE_DMA
 139 #define SLUB_DMA __GFP_DMA
 140 #else
 141 /* Disable DMA functionality */
 142 #define SLUB_DMA (__force gfp_t)0
 143 #endif
 144
 145 /*
 146  * We keep the general caches in an array of slab caches that are used for
 147  * 2^x bytes of allocations.
 148  */
 149 extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 150
 151 /*
 152  * Sorry that the following has to be that ugly but some versions of GCC
 153  * have trouble with constant propagation and loops.
 154  */
 155 static __always_inline int kmalloc_index(size_t size)
 156 {
 157         if (!size)
 158                 return 0;
 159
 160         if (size <= KMALLOC_MIN_SIZE)
 161                 return KMALLOC_SHIFT_LOW;
 162
 163         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 164                 return 1;
 165         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 166                 return 2;
 167         if (size <=          8) return 3;
 168         if (size <=         16) return 4;
 169         if (size <=         32) return 5;
 170         if (size <=         64) return 6;
 171         if (size <=        128) return 7;
 172         if (size <=        256) return 8;
 173         if (size <=        512) return 9;
 174         if (size <=       1024) return 10;
 175         if (size <=   2 * 1024) return 11;
 176         if (size <=   4 * 1024) return 12;
 177 /*
 178  * The following is only needed to support architectures with a larger page
 179  * size than 4k. We need to support 2 * PAGE_SIZE here. So for a 64k page
 180  * size we would have to go up to 128k.
 181  */
 182         if (size <=   8 * 1024) return 13;
 183         if (size <=  16 * 1024) return 14;
 184         if (size <=  32 * 1024) return 15;
 185         if (size <=  64 * 1024) return 16;
 186         if (size <= 128 * 1024) return 17;
 187         if (size <= 256 * 1024) return 18;
 188         if (size <= 512 * 1024) return 19;
 189         if (size <= 1024 * 1024) return 20;
 190         if (size <=  2 * 1024 * 1024) return 21;
 191         BUG();
 192         return -1; /* Will never be reached */
 193
 194 /*
 195  * What we really wanted to do and cannot do because of compiler issues is:
 196  *      int i;
 197  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 198  *              if (size <= (1 << i))
 199  *                      return i;
 200  */
 201 }
 202
 203 /*
 204  * Find the slab cache for a given combination of allocation flags and size.
 205  *
 206  * This ought to end up with a global pointer to the right cache
 207  * in kmalloc_caches.
 208  */
 209 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 210 {
 211         int index = kmalloc_index(size);
 212
 213         if (index == 0)
 214                 return NULL;
 215
 216         return kmalloc_caches[index];
 217 }
 218
 219 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 220 void *__kmalloc(size_t size, gfp_t flags);
 221
 222 static __always_inline void *
 223 kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 224 {
 225         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 226         kmemleak_alloc(ret, size, 1, flags);
 227         return ret;
 228 }
 229
 230 /**
 231  * Calling this on allocated memory will check that the memory
 232  * is expected to be in use, and print warnings if not.
 233  */
 234 #ifdef CONFIG_SLUB_DEBUG
 235 extern bool verify_mem_not_deleted(const void *x);
 236 #else
 237 static inline bool verify_mem_not_deleted(const void *x)
 238 {
 239         return true;
 240 }
 241 #endif
 242
 243 #ifdef CONFIG_TRACING
 244 extern void *
 245 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 246 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 247 #else
 248 static __always_inline void *
 249 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 250 {
 251         return kmem_cache_alloc(s, gfpflags);
 252 }
 253
 254 static __always_inline void *
 255 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 256 {
 257         return kmalloc_order(size, flags, order);
 258 }
 259 #endif
 260
 261 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 262 {
 263         unsigned int order = get_order(size);
 264         return kmalloc_order_trace(size, flags, order);
 265 }
 266
 267 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 268 {
 269         if (__builtin_constant_p(size)) {
 270                 if (size > SLUB_MAX_SIZE)
 271                         return kmalloc_large(size, flags);
 272
 273                 if (!(flags & SLUB_DMA)) {
 274                         struct kmem_cache *s = kmalloc_slab(size);
 275
 276                         if (!s)
 277                                 return ZERO_SIZE_PTR;
 278
 279                         return kmem_cache_alloc_trace(s, flags, size);
 280                 }
 281         }
 282         return __kmalloc(size, flags);
 283 }
 284
 285 #ifdef CONFIG_NUMA
 286 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 287 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 288
 289 #ifdef CONFIG_TRACING
 290 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 291                                            gfp_t gfpflags,
 292                                            int node, size_t size);
 293 #else
 294 static __always_inline void *
 295 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 296                               gfp_t gfpflags,
 297                               int node, size_t size)
 298 {
 299         return kmem_cache_alloc_node(s, gfpflags, node);
 300 }
 301 #endif
 302
 303 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 304 {
 305         if (__builtin_constant_p(size) &&
 306                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 307                         struct kmem_cache *s = kmalloc_slab(size);
 308
 309                 if (!s)
 310                         return ZERO_SIZE_PTR;
 311
 312                 return kmem_cache_alloc_node_trace(s, flags, node, size);
 313         }
 314         return __kmalloc_node(size, flags, node);
 315 }
 316 #endif
 317
 318 #endif /* _LINUX_SLUB_DEF_H */