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         int node;               /* The node of the page (or -1 for debug) */
  52 #ifdef CONFIG_SLUB_STATS
  53         unsigned stat[NR_SLUB_STAT_ITEMS];
  54 #endif
  55 };
  56
  57 struct kmem_cache_node {
  58         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  59         unsigned long nr_partial;
  60         struct list_head partial;
  61 #ifdef CONFIG_SLUB_DEBUG
  62         atomic_long_t nr_slabs;
  63         atomic_long_t total_objects;
  64         struct list_head full;
  65 #endif
  66 };
  67
  68 /*
  69  * Word size structure that can be atomically updated or read and that
  70  * contains both the order and the number of objects that a slab of the
  71  * given order would contain.
  72  */
  73 struct kmem_cache_order_objects {
  74         unsigned long x;
  75 };
  76
  77 /*
  78  * Slab cache management.
  79  */
  80 struct kmem_cache {
  81         struct kmem_cache_cpu __percpu *cpu_slab;
  82         /* Used for retriving partial slabs etc */
  83         unsigned long flags;
  84         unsigned long min_partial;
  85         int size;               /* The size of an object including meta data */
  86         int objsize;            /* The size of an object without meta data */
  87         int offset;             /* Free pointer offset. */
  88         int cpu_partial;        /* Number of per cpu partial objects to keep around */
  89         struct kmem_cache_order_objects oo;
  90
  91         /* Allocation and freeing of slabs */
  92         struct kmem_cache_order_objects max;
  93         struct kmem_cache_order_objects min;
  94         gfp_t allocflags;       /* gfp flags to use on each alloc */
  95         int refcount;           /* Refcount for slab cache destroy */
  96         void (*ctor)(void *);
  97         int inuse;              /* Offset to metadata */
  98         int align;              /* Alignment */
  99         int reserved;           /* Reserved bytes at the end of slabs */
 100         const char *name;       /* Name (only for display!) */
 101         struct list_head list;  /* List of slab caches */
 102 #ifdef CONFIG_SYSFS
 103         struct kobject kobj;    /* For sysfs */
 104 #endif
 105
 106 #ifdef CONFIG_NUMA
 107         /*
 108          * Defragmentation by allocating from a remote node.
 109          */
 110         int remote_node_defrag_ratio;
 111 #endif
 112         struct kmem_cache_node *node[MAX_NUMNODES];
 113 };
 114
 115 /*
 116  * Kmalloc subsystem.
 117  */
 118 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 119 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 120 #else
 121 #define KMALLOC_MIN_SIZE 8
 122 #endif
 123
 124 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 125
 126 /*
 127  * Maximum kmalloc object size handled by SLUB. Larger object allocations
 128  * are passed through to the page allocator. The page allocator "fastpath"
 129  * is relatively slow so we need this value sufficiently high so that
 130  * performance critical objects are allocated through the SLUB fastpath.
 131  *
 132  * This should be dropped to PAGE_SIZE / 2 once the page allocator
 133  * "fastpath" becomes competitive with the slab allocator fastpaths.
 134  */
 135 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 136
 137 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 138
 139 #ifdef CONFIG_ZONE_DMA
 140 #define SLUB_DMA __GFP_DMA
 141 #else
 142 /* Disable DMA functionality */
 143 #define SLUB_DMA (__force gfp_t)0
 144 #endif
 145
 146 /*
 147  * We keep the general caches in an array of slab caches that are used for
 148  * 2^x bytes of allocations.
 149  */
 150 extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 151
 152 /*
 153  * Sorry that the following has to be that ugly but some versions of GCC
 154  * have trouble with constant propagation and loops.
 155  */
 156 static __always_inline int kmalloc_index(size_t size)
 157 {
 158         if (!size)
 159                 return 0;
 160
 161         if (size <= KMALLOC_MIN_SIZE)
 162                 return KMALLOC_SHIFT_LOW;
 163
 164         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 165                 return 1;
 166         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 167                 return 2;
 168         if (size <=          8) return 3;
 169         if (size <=         16) return 4;
 170         if (size <=         32) return 5;
 171         if (size <=         64) return 6;
 172         if (size <=        128) return 7;
 173         if (size <=        256) return 8;
 174         if (size <=        512) return 9;
 175         if (size <=       1024) return 10;
 176         if (size <=   2 * 1024) return 11;
 177         if (size <=   4 * 1024) return 12;
 178 /*
 179  * The following is only needed to support architectures with a larger page
 180  * size than 4k. We need to support 2 * PAGE_SIZE here. So for a 64k page
 181  * size we would have to go up to 128k.
 182  */
 183         if (size <=   8 * 1024) return 13;
 184         if (size <=  16 * 1024) return 14;
 185         if (size <=  32 * 1024) return 15;
 186         if (size <=  64 * 1024) return 16;
 187         if (size <= 128 * 1024) return 17;
 188         if (size <= 256 * 1024) return 18;
 189         if (size <= 512 * 1024) return 19;
 190         if (size <= 1024 * 1024) return 20;
 191         if (size <=  2 * 1024 * 1024) return 21;
 192         BUG();
 193         return -1; /* Will never be reached */
 194
 195 /*
 196  * What we really wanted to do and cannot do because of compiler issues is:
 197  *      int i;
 198  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 199  *              if (size <= (1 << i))
 200  *                      return i;
 201  */
 202 }
 203
 204 /*
 205  * Find the slab cache for a given combination of allocation flags and size.
 206  *
 207  * This ought to end up with a global pointer to the right cache
 208  * in kmalloc_caches.
 209  */
 210 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 211 {
 212         int index = kmalloc_index(size);
 213
 214         if (index == 0)
 215                 return NULL;
 216
 217         return kmalloc_caches[index];
 218 }
 219
 220 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 221 void *__kmalloc(size_t size, gfp_t flags);
 222
 223 static __always_inline void *
 224 kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 225 {
 226         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 227         kmemleak_alloc(ret, size, 1, flags);
 228         return ret;
 229 }
 230
 231 /**
 232  * Calling this on allocated memory will check that the memory
 233  * is expected to be in use, and print warnings if not.
 234  */
 235 #ifdef CONFIG_SLUB_DEBUG
 236 extern bool verify_mem_not_deleted(const void *x);
 237 #else
 238 static inline bool verify_mem_not_deleted(const void *x)
 239 {
 240         return true;
 241 }
 242 #endif
 243
 244 #ifdef CONFIG_TRACING
 245 extern void *
 246 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 247 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 248 #else
 249 static __always_inline void *
 250 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 251 {
 252         return kmem_cache_alloc(s, gfpflags);
 253 }
 254
 255 static __always_inline void *
 256 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 257 {
 258         return kmalloc_order(size, flags, order);
 259 }
 260 #endif
 261
 262 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 263 {
 264         unsigned int order = get_order(size);
 265         return kmalloc_order_trace(size, flags, order);
 266 }
 267
 268 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 269 {
 270         if (__builtin_constant_p(size)) {
 271                 if (size > SLUB_MAX_SIZE)
 272                         return kmalloc_large(size, flags);
 273
 274                 if (!(flags & SLUB_DMA)) {
 275                         struct kmem_cache *s = kmalloc_slab(size);
 276
 277                         if (!s)
 278                                 return ZERO_SIZE_PTR;
 279
 280                         return kmem_cache_alloc_trace(s, flags, size);
 281                 }
 282         }
 283         return __kmalloc(size, flags);
 284 }
 285
 286 #ifdef CONFIG_NUMA
 287 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 288 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 289
 290 #ifdef CONFIG_TRACING
 291 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 292                                            gfp_t gfpflags,
 293                                            int node, size_t size);
 294 #else
 295 static __always_inline void *
 296 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 297                               gfp_t gfpflags,
 298                               int node, size_t size)
 299 {
 300         return kmem_cache_alloc_node(s, gfpflags, node);
 301 }
 302 #endif
 303
 304 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 305 {
 306         if (__builtin_constant_p(size) &&
 307                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 308                         struct kmem_cache *s = kmalloc_slab(size);
 309
 310                 if (!s)
 311                         return ZERO_SIZE_PTR;
 312
 313                 return kmem_cache_alloc_node_trace(s, flags, node, size);
 314         }
 315         return __kmalloc_node(size, flags, node);
 316 }
 317 #endif
 318
 319 #endif /* _LINUX_SLUB_DEF_H */