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