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