linux/include/linux/slub_def.h
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   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
  17enum 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
  46struct 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
  56struct 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 */
  72struct kmem_cache_order_objects {
  73        unsigned long x;
  74};
  75
  76/*
  77 * Slab cache management.
  78 */
  79struct 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 */
 149extern 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 */
 155static __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 */
 209static __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
 219void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 220void *__kmalloc(size_t size, gfp_t flags);
 221
 222static __always_inline void *
 223kmalloc_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
 235extern bool verify_mem_not_deleted(const void *x);
 236#else
 237static inline bool verify_mem_not_deleted(const void *x)
 238{
 239        return true;
 240}
 241#endif
 242
 243#ifdef CONFIG_TRACING
 244extern void *
 245kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 246extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 247#else
 248static __always_inline void *
 249kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 250{
 251        return kmem_cache_alloc(s, gfpflags);
 252}
 253
 254static __always_inline void *
 255kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 256{
 257        return kmalloc_order(size, flags, order);
 258}
 259#endif
 260
 261static __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
 267static __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
 286void *__kmalloc_node(size_t size, gfp_t flags, int node);
 287void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 288
 289#ifdef CONFIG_TRACING
 290extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 291                                           gfp_t gfpflags,
 292                                           int node, size_t size);
 293#else
 294static __always_inline void *
 295kmem_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
 303static __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 */
 319
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