LXR linux/include/linux/slub

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_SLUB_DEF_H
   3#define _LINUX_SLUB_DEF_H
   4
   5/*
   6 * SLUB : A Slab allocator without object queues.
   7 *
   8 * (C) 2007 SGI, Christoph Lameter
   9 */
  10#include <linux/kfence.h>
  11#include <linux/kobject.h>
  12#include <linux/reciprocal_div.h>
  13
  14enum stat_item {
  15        ALLOC_FASTPATH,         /* Allocation from cpu slab */
  16        ALLOC_SLOWPATH,         /* Allocation by getting a new cpu slab */
  17        FREE_FASTPATH,          /* Free to cpu slab */
  18        FREE_SLOWPATH,          /* Freeing not to cpu slab */
  19        FREE_FROZEN,            /* Freeing to frozen slab */
  20        FREE_ADD_PARTIAL,       /* Freeing moves slab to partial list */
  21        FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
  22        ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from node partial list */
  23        ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
  24        ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
  25        ALLOC_NODE_MISMATCH,    /* Switching cpu slab */
  26        FREE_SLAB,              /* Slab freed to the page allocator */
  27        CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
  28        DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
  29        DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
  30        DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
  31        DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
  32        DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
  33        DEACTIVATE_BYPASS,      /* Implicit deactivation */
  34        ORDER_FALLBACK,         /* Number of times fallback was necessary */
  35        CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
  36        CMPXCHG_DOUBLE_FAIL,    /* Number of times that cmpxchg double did not match */
  37        CPU_PARTIAL_ALLOC,      /* Used cpu partial on alloc */
  38        CPU_PARTIAL_FREE,       /* Refill cpu partial on free */
  39        CPU_PARTIAL_NODE,       /* Refill cpu partial from node partial */
  40        CPU_PARTIAL_DRAIN,      /* Drain cpu partial to node partial */
  41        NR_SLUB_STAT_ITEMS };
  42
  43struct 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#ifdef CONFIG_SLUB_CPU_PARTIAL
  48        struct page *partial;   /* Partially allocated frozen slabs */
  49#endif
  50#ifdef CONFIG_SLUB_STATS
  51        unsigned stat[NR_SLUB_STAT_ITEMS];
  52#endif
  53};
  54
  55#ifdef CONFIG_SLUB_CPU_PARTIAL
  56#define slub_percpu_partial(c)          ((c)->partial)
  57
  58#define slub_set_percpu_partial(c, p)           \
  59({                                              \
  60        slub_percpu_partial(c) = (p)->next;     \
  61})
  62
  63#define slub_percpu_partial_read_once(c)     READ_ONCE(slub_percpu_partial(c))
  64#else
  65#define slub_percpu_partial(c)                  NULL
  66
  67#define slub_set_percpu_partial(c, p)
  68
  69#define slub_percpu_partial_read_once(c)        NULL
  70#endif // CONFIG_SLUB_CPU_PARTIAL
  71
  72/*
  73 * Word size structure that can be atomically updated or read and that
  74 * contains both the order and the number of objects that a slab of the
  75 * given order would contain.
  76 */
  77struct kmem_cache_order_objects {
  78        unsigned int x;
  79};
  80
  81/*
  82 * Slab cache management.
  83 */
  84struct kmem_cache {
  85        struct kmem_cache_cpu __percpu *cpu_slab;
  86        /* Used for retrieving partial slabs, etc. */
  87        slab_flags_t flags;
  88        unsigned long min_partial;
  89        unsigned int size;      /* The size of an object including metadata */
  90        unsigned int object_size;/* The size of an object without metadata */
  91        struct reciprocal_value reciprocal_size;
  92        unsigned int offset;    /* Free pointer offset */
  93#ifdef CONFIG_SLUB_CPU_PARTIAL
  94        /* Number of per cpu partial objects to keep around */
  95        unsigned int cpu_partial;
  96#endif
  97        struct kmem_cache_order_objects oo;
  98
  99        /* Allocation and freeing of slabs */
 100        struct kmem_cache_order_objects max;
 101        struct kmem_cache_order_objects min;
 102        gfp_t allocflags;       /* gfp flags to use on each alloc */
 103        int refcount;           /* Refcount for slab cache destroy */
 104        void (*ctor)(void *);
 105        unsigned int inuse;             /* Offset to metadata */
 106        unsigned int align;             /* Alignment */
 107        unsigned int red_left_pad;      /* Left redzone padding size */
 108        const char *name;       /* Name (only for display!) */
 109        struct list_head list;  /* List of slab caches */
 110#ifdef CONFIG_SYSFS
 111        struct kobject kobj;    /* For sysfs */
 112#endif
 113#ifdef CONFIG_SLAB_FREELIST_HARDENED
 114        unsigned long random;
 115#endif
 116
 117#ifdef CONFIG_NUMA
 118        /*
 119         * Defragmentation by allocating from a remote node.
 120         */
 121        unsigned int remote_node_defrag_ratio;
 122#endif
 123
 124#ifdef CONFIG_SLAB_FREELIST_RANDOM
 125        unsigned int *random_seq;
 126#endif
 127
 128#ifdef CONFIG_KASAN
 129        struct kasan_cache kasan_info;
 130#endif
 131
 132        unsigned int useroffset;        /* Usercopy region offset */
 133        unsigned int usersize;          /* Usercopy region size */
 134
 135        struct kmem_cache_node *node[MAX_NUMNODES];
 136};
 137
 138#ifdef CONFIG_SLUB_CPU_PARTIAL
 139#define slub_cpu_partial(s)             ((s)->cpu_partial)
 140#define slub_set_cpu_partial(s, n)              \
 141({                                              \
 142        slub_cpu_partial(s) = (n);              \
 143})
 144#else
 145#define slub_cpu_partial(s)             (0)
 146#define slub_set_cpu_partial(s, n)
 147#endif /* CONFIG_SLUB_CPU_PARTIAL */
 148
 149#ifdef CONFIG_SYSFS
 150#define SLAB_SUPPORTS_SYSFS
 151void sysfs_slab_unlink(struct kmem_cache *);
 152void sysfs_slab_release(struct kmem_cache *);
 153#else
 154static inline void sysfs_slab_unlink(struct kmem_cache *s)
 155{
 156}
 157static inline void sysfs_slab_release(struct kmem_cache *s)
 158{
 159}
 160#endif
 161
 162void object_err(struct kmem_cache *s, struct page *page,
 163                u8 *object, char *reason);
 164
 165void *fixup_red_left(struct kmem_cache *s, void *p);
 166
 167static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
 168                                void *x) {
 169        void *object = x - (x - page_address(page)) % cache->size;
 170        void *last_object = page_address(page) +
 171                (page->objects - 1) * cache->size;
 172        void *result = (unlikely(object > last_object)) ? last_object : object;
 173
 174        result = fixup_red_left(cache, result);
 175        return result;
 176}
 177
 178/* Determine object index from a given position */
 179static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
 180                                          void *addr, void *obj)
 181{
 182        return reciprocal_divide(kasan_reset_tag(obj) - addr,
 183                                 cache->reciprocal_size);
 184}
 185
 186static inline unsigned int obj_to_index(const struct kmem_cache *cache,
 187                                        const struct page *page, void *obj)
 188{
 189        if (is_kfence_address(obj))
 190                return 0;
 191        return __obj_to_index(cache, page_address(page), obj);
 192}
 193
 194static inline int objs_per_slab_page(const struct kmem_cache *cache,
 195                                     const struct page *page)
 196{
 197        return page->objects;
 198}
 199#endif /* _LINUX_SLUB_DEF_H */
 200