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#ifdef CONFIG_MEMCG_KMEM
 105        struct memcg_cache_params *memcg_params;
 106        int max_attr_size; /* for propagation, maximum size of a stored attr */
 107#endif
 108
 109#ifdef CONFIG_NUMA
 110        /*
 111         * Defragmentation by allocating from a remote node.
 112         */
 113        int remote_node_defrag_ratio;
 114#endif
 115        struct kmem_cache_node *node[MAX_NUMNODES];
 116};
 117
 118/*
 119 * Kmalloc subsystem.
 120 */
 121#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 122#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 123#else
 124#define KMALLOC_MIN_SIZE 8
 125#endif
 126
 127#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 128
 129/*
 130 * Maximum kmalloc object size handled by SLUB. Larger object allocations
 131 * are passed through to the page allocator. The page allocator "fastpath"
 132 * is relatively slow so we need this value sufficiently high so that
 133 * performance critical objects are allocated through the SLUB fastpath.
 134 *
 135 * This should be dropped to PAGE_SIZE / 2 once the page allocator
 136 * "fastpath" becomes competitive with the slab allocator fastpaths.
 137 */
 138#define SLUB_MAX_SIZE (2 * PAGE_SIZE)
 139
 140#define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 141
 142#ifdef CONFIG_ZONE_DMA
 143#define SLUB_DMA __GFP_DMA
 144#else
 145/* Disable DMA functionality */
 146#define SLUB_DMA (__force gfp_t)0
 147#endif
 148
 149/*
 150 * We keep the general caches in an array of slab caches that are used for
 151 * 2^x bytes of allocations.
 152 */
 153extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 154
 155/*
 156 * Sorry that the following has to be that ugly but some versions of GCC
 157 * have trouble with constant propagation and loops.
 158 */
 159static __always_inline int kmalloc_index(size_t size)
 160{
 161        if (!size)
 162                return 0;
 163
 164        if (size <= KMALLOC_MIN_SIZE)
 165                return KMALLOC_SHIFT_LOW;
 166
 167        if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 168                return 1;
 169        if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 170                return 2;
 171        if (size <=          8) return 3;
 172        if (size <=         16) return 4;
 173        if (size <=         32) return 5;
 174        if (size <=         64) return 6;
 175        if (size <=        128) return 7;
 176        if (size <=        256) return 8;
 177        if (size <=        512) return 9;
 178        if (size <=       1024) return 10;
 179        if (size <=   2 * 1024) return 11;
 180        if (size <=   4 * 1024) return 12;
 181/*
 182 * The following is only needed to support architectures with a larger page
 183 * size than 4k. We need to support 2 * PAGE_SIZE here. So for a 64k page
 184 * size we would have to go up to 128k.
 185 */
 186        if (size <=   8 * 1024) return 13;
 187        if (size <=  16 * 1024) return 14;
 188        if (size <=  32 * 1024) return 15;
 189        if (size <=  64 * 1024) return 16;
 190        if (size <= 128 * 1024) return 17;
 191        if (size <= 256 * 1024) return 18;
 192        if (size <= 512 * 1024) return 19;
 193        if (size <= 1024 * 1024) return 20;
 194        if (size <=  2 * 1024 * 1024) return 21;
 195        BUG();
 196        return -1; /* Will never be reached */
 197
 198/*
 199 * What we really wanted to do and cannot do because of compiler issues is:
 200 *      int i;
 201 *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 202 *              if (size <= (1 << i))
 203 *                      return i;
 204 */
 205}
 206
 207/*
 208 * Find the slab cache for a given combination of allocation flags and size.
 209 *
 210 * This ought to end up with a global pointer to the right cache
 211 * in kmalloc_caches.
 212 */
 213static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 214{
 215        int index = kmalloc_index(size);
 216
 217        if (index == 0)
 218                return NULL;
 219
 220        return kmalloc_caches[index];
 221}
 222
 223void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 224void *__kmalloc(size_t size, gfp_t flags);
 225
 226static __always_inline void *
 227kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 228{
 229        void *ret;
 230
 231        flags |= (__GFP_COMP | __GFP_KMEMCG);
 232        ret = (void *) __get_free_pages(flags, order);
 233        kmemleak_alloc(ret, size, 1, flags);
 234        return ret;
 235}
 236
 237/**
 238 * Calling this on allocated memory will check that the memory
 239 * is expected to be in use, and print warnings if not.
 240 */
 241#ifdef CONFIG_SLUB_DEBUG
 242extern bool verify_mem_not_deleted(const void *x);
 243#else
 244static inline bool verify_mem_not_deleted(const void *x)
 245{
 246        return true;
 247}
 248#endif
 249
 250#ifdef CONFIG_TRACING
 251extern void *
 252kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size);
 253extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order);
 254#else
 255static __always_inline void *
 256kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 257{
 258        return kmem_cache_alloc(s, gfpflags);
 259}
 260
 261static __always_inline void *
 262kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 263{
 264        return kmalloc_order(size, flags, order);
 265}
 266#endif
 267
 268static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 269{
 270        unsigned int order = get_order(size);
 271        return kmalloc_order_trace(size, flags, order);
 272}
 273
 274static __always_inline void *kmalloc(size_t size, gfp_t flags)
 275{
 276        if (__builtin_constant_p(size)) {
 277                if (size > SLUB_MAX_SIZE)
 278                        return kmalloc_large(size, flags);
 279
 280                if (!(flags & SLUB_DMA)) {
 281                        struct kmem_cache *s = kmalloc_slab(size);
 282
 283                        if (!s)
 284                                return ZERO_SIZE_PTR;
 285
 286                        return kmem_cache_alloc_trace(s, flags, size);
 287                }
 288        }
 289        return __kmalloc(size, flags);
 290}
 291
 292#ifdef CONFIG_NUMA
 293void *__kmalloc_node(size_t size, gfp_t flags, int node);
 294void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 295
 296#ifdef CONFIG_TRACING
 297extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 298                                           gfp_t gfpflags,
 299                                           int node, size_t size);
 300#else
 301static __always_inline void *
 302kmem_cache_alloc_node_trace(struct kmem_cache *s,
 303                              gfp_t gfpflags,
 304                              int node, size_t size)
 305{
 306        return kmem_cache_alloc_node(s, gfpflags, node);
 307}
 308#endif
 309
 310static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 311{
 312        if (__builtin_constant_p(size) &&
 313                size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
 314                        struct kmem_cache *s = kmalloc_slab(size);
 315
 316                if (!s)
 317                        return ZERO_SIZE_PTR;
 318
 319                return kmem_cache_alloc_node_trace(s, flags, node, size);
 320        }
 321        return __kmalloc_node(size, flags, node);
 322}
 323#endif
 324
 325#endif /* _LINUX_SLUB_DEF_H */
 326
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