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         ALLOC_NODE_MISMATCH,    /* Switching cpu slab */
  28         FREE_SLAB,              /* Slab freed to the page allocator */
  29         CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
  30         DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
  31         DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
  32         DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
  33         DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
  34         DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
  35         DEACTIVATE_BYPASS,      /* Implicit deactivation */
  36         ORDER_FALLBACK,         /* Number of times fallback was necessary */
  37         CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
  38         CMPXCHG_DOUBLE_FAIL,    /* Number of times that cmpxchg double did not match */
  39         CPU_PARTIAL_ALLOC,      /* Used cpu partial on alloc */
  40         CPU_PARTIAL_FREE,       /* USed cpu partial on free */
  41         NR_SLUB_STAT_ITEMS };
  42
  43 struct kmem_cache_cpu {
  44         void **freelist;        /* Pointer to next available object */
  45         unsigned long tid;      /* Globally unique transaction id */
  46         struct page *page;      /* The slab from which we are allocating */
  47         struct page *partial;   /* Partially allocated frozen slabs */
  48         int node;               /* The node of the page (or -1 for debug) */
  49 #ifdef CONFIG_SLUB_STATS
  50         unsigned stat[NR_SLUB_STAT_ITEMS];
  51 #endif
  52 };
  53
  54 struct kmem_cache_node {
  55         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  56         unsigned long nr_partial;
  57         struct list_head partial;
  58 #ifdef CONFIG_SLUB_DEBUG
  59         atomic_long_t nr_slabs;
  60         atomic_long_t total_objects;
  61         struct list_head full;
  62 #endif
  63 };
  64
  65 /*
  66  * Word size structure that can be atomically updated or read and that
  67  * contains both the order and the number of objects that a slab of the
  68  * given order would contain.
  69  */
  70 struct kmem_cache_order_objects {
  71         unsigned long x;
  72 };
  73
  74 /*
  75  * Slab cache management.
  76  */
  77 struct kmem_cache {
  78         struct kmem_cache_cpu __percpu *cpu_slab;
  79         /* Used for retriving partial slabs etc */
  80         unsigned long flags;
  81         unsigned long min_partial;
  82         int size;               /* The size of an object including meta data */
  83         int objsize;            /* The size of an object without meta data */
  84         int offset;             /* Free pointer offset. */
  85         int cpu_partial;        /* Number of per cpu partial objects to keep around */
  86         struct kmem_cache_order_objects oo;
  87
  88         /* Allocation and freeing of slabs */
  89         struct kmem_cache_order_objects max;
  90         struct kmem_cache_order_objects min;
  91         gfp_t allocflags;       /* gfp flags to use on each alloc */
  92         int refcount;           /* Refcount for slab cache destroy */
  93         void (*ctor)(void *);
  94         int inuse;              /* Offset to metadata */
  95         int align;              /* Alignment */
  96         int reserved;           /* Reserved bytes at the end of slabs */
  97         const char *name;       /* Name (only for display!) */
  98         struct list_head list;  /* List of slab caches */
  99 #ifdef CONFIG_SYSFS
 100         struct kobject kobj;    /* For sysfs */
 101 #endif
 102
 103 #ifdef CONFIG_NUMA
 104         /*
 105          * Defragmentation by allocating from a remote node.
 106          */
 107         int remote_node_defrag_ratio;
 108 #endif
 109         struct kmem_cache_node *node[MAX_NUMNODES];
 110 };
 111
 112 /*
 113  * Kmalloc subsystem.
 114  */
 115 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 116 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 117 #else
 118 #define KMALLOC_MIN_SIZE 8
 119 #endif
 120
 121 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 122
 123 /*
 124  * Maximum kmalloc object size handled by SLUB. Larger object allocations
 125  * are passed through to the page allocator. The page allocator "fastpath"
 126  * is relatively slow so we need this value sufficiently high so that
 127  * performance critical objects are allocated through the SLUB fastpath.
 128  *
 129  * This should be dropped to PAGE_SIZE / 2 once the page allocator
 130  * "fastpath" becomes competitive with the slab allocator fastpaths.
 131  */
 132 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 133
 134 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 135
 136 #ifdef CONFIG_ZONE_DMA
 137 #define SLUB_DMA __GFP_DMA
 138 #else
 139 /* Disable DMA functionality */
 140 #define SLUB_DMA (__force gfp_t)0
 141 #endif
 142
 143 /*
 144  * We keep the general caches in an array of slab caches that are used for
 145  * 2^x bytes of allocations.
 146  */
 147 extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 148
 149 /*
 150  * Sorry that the following has to be that ugly but some versions of GCC
 151  * have trouble with constant propagation and loops.
 152  */
 153 static __always_inline int kmalloc_index(size_t size)
 154 {
 155         if (!size)
 156                 return 0;
 157
 158         if (size <= KMALLOC_MIN_SIZE)
 159                 return KMALLOC_SHIFT_LOW;
 160
 161         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 162                 return 1;
 163         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 164                 return 2;
 165         if (size <=          8) return 3;
 166         if (size <=         16) return 4;
 167         if (size <=         32) return 5;
 168         if (size <=         64) return 6;
 169         if (size <=        128) return 7;
 170         if (size <=        256) return 8;
 171         if (size <=        512) return 9;
 172         if (size <=       1024) return 10;
 173         if (size <=   2 * 1024) return 11;
 174         if (size <=   4 * 1024) return 12;
 175 /*
 176  * The following is only needed to support architectures with a larger page
 177  * size than 4k. We need to support 2 * PAGE_SIZE here. So for a 64k page
 178  * size we would have to go up to 128k.
 179  */
 180         if (size <=   8 * 1024) return 13;
 181         if (size <=  16 * 1024) return 14;
 182         if (size <=  32 * 1024) return 15;
 183         if (size <=  64 * 1024) return 16;
 184         if (size <= 128 * 1024) return 17;
 185         if (size <= 256 * 1024) return 18;
 186         if (size <= 512 * 1024) return 19;
 187         if (size <= 1024 * 1024) return 20;
 188         if (size <=  2 * 1024 * 1024) return 21;
 189         BUG();
 190         return -1; /* Will never be reached */
 191
 192 /*
 193  * What we really wanted to do and cannot do because of compiler issues is:
 194  *      int i;
 195  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 196  *              if (size <= (1 << i))
 197  *                      return i;
 198  */
 199 }
 200
 201 /*
 202  * Find the slab cache for a given combination of allocation flags and size.
 203  *
 204  * This ought to end up with a global pointer to the right cache
 205  * in kmalloc_caches.
 206  */
 207 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 208 {
 209         int index = kmalloc_index(size);
 210
 211         if (index == 0)
 212                 return NULL;
 213
 214         return kmalloc_caches[index];
 215 }
 216
 217 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 218 void *__kmalloc(size_t size, gfp_t flags);
 219
 220 static __always_inline void *
 221 kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 222 {
 223         void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
 224         kmemleak_alloc(ret, size, 1, flags);
 225         return ret;
 226 }
 227
 228 /**
 229  * Calling this on allocated memory will check that the memory
 230  * is expected to be in use, and print warnings if not.
 231  */
 232 #ifdef CONFIG_SLUB_DEBUG
 233 extern bool verify_mem_not_deleted(const void *x);
 234 #else
 235 static inline bool verify_mem_not_deleted(const void *x)
 236 {
 237         return true;
 238 }
 239 #endif
 240
 241 #ifdef CONFIG_TRACING
 242 extern void *
 243 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 244 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 245 #else
 246 static __always_inline void *
 247 kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 248 {
 249         return kmem_cache_alloc(s, gfpflags);
 250 }
 251
 252 static __always_inline void *
 253 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 254 {
 255         return kmalloc_order(size, flags, order);
 256 }
 257 #endif
 258
 259 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 260 {
 261         unsigned int order = get_order(size);
 262         return kmalloc_order_trace(size, flags, order);
 263 }
 264
 265 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 266 {
 267         if (__builtin_constant_p(size)) {
 268                 if (size > SLUB_MAX_SIZE)
 269                         return kmalloc_large(size, flags);
 270
 271                 if (!(flags & SLUB_DMA)) {
 272                         struct kmem_cache *s = kmalloc_slab(size);
 273
 274                         if (!s)
 275                                 return ZERO_SIZE_PTR;
 276
 277                         return kmem_cache_alloc_trace(s, flags, size);
 278                 }
 279         }
 280         return __kmalloc(size, flags);
 281 }
 282
 283 #ifdef CONFIG_NUMA
 284 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 285 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 286
 287 #ifdef CONFIG_TRACING
 288 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 289                                            gfp_t gfpflags,
 290                                            int node, size_t size);
 291 #else
 292 static __always_inline void *
 293 kmem_cache_alloc_node_trace(struct kmem_cache *s,
 294                               gfp_t gfpflags,
 295                               int node, size_t size)
 296 {
 297         return kmem_cache_alloc_node(s, gfpflags, node);
 298 }
 299 #endif
 300
 301 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 302 {
 303         if (__builtin_constant_p(size) &&
 304                 size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 305                         struct kmem_cache *s = kmalloc_slab(size);
 306
 307                 if (!s)
 308                         return ZERO_SIZE_PTR;
 309
 310                 return kmem_cache_alloc_node_trace(s, flags, node, size);
 311         }
 312         return __kmalloc_node(size, flags, node);
 313 }
 314 #endif
 315
 316 #endif /* _LINUX_SLUB_DEF_H */