1 /* SPDX-License-Identifier: GPL-2.0 */
5 * Internal slab definitions
10 * Common fields provided in kmem_cache by all slab allocators
11 * This struct is either used directly by the allocator (SLOB)
12 * or the allocator must include definitions for all fields
13 * provided in kmem_cache_common in their definition of kmem_cache.
15 * Once we can do anonymous structs (C11 standard) we could put a
16 * anonymous struct definition in these allocators so that the
17 * separate allocations in the kmem_cache structure of SLAB and
18 * SLUB is no longer needed.
21 unsigned int object_size
;/* The original size of the object */
22 unsigned int size
; /* The aligned/padded/added on size */
23 unsigned int align
; /* Alignment as calculated */
24 slab_flags_t flags
; /* Active flags on the slab */
25 unsigned int useroffset
;/* Usercopy region offset */
26 unsigned int usersize
; /* Usercopy region size */
27 const char *name
; /* Slab name for sysfs */
28 int refcount
; /* Use counter */
29 void (*ctor
)(void *); /* Called on object slot creation */
30 struct list_head list
; /* List of all slab caches on the system */
33 #endif /* CONFIG_SLOB */
36 #include <linux/slab_def.h>
40 #include <linux/slub_def.h>
43 #include <linux/memcontrol.h>
44 #include <linux/fault-inject.h>
45 #include <linux/kasan.h>
46 #include <linux/kmemleak.h>
47 #include <linux/random.h>
48 #include <linux/sched/mm.h>
51 * State of the slab allocator.
53 * This is used to describe the states of the allocator during bootup.
54 * Allocators use this to gradually bootstrap themselves. Most allocators
55 * have the problem that the structures used for managing slab caches are
56 * allocated from slab caches themselves.
59 DOWN
, /* No slab functionality yet */
60 PARTIAL
, /* SLUB: kmem_cache_node available */
61 PARTIAL_NODE
, /* SLAB: kmalloc size for node struct available */
62 UP
, /* Slab caches usable but not all extras yet */
63 FULL
/* Everything is working */
66 extern enum slab_state slab_state
;
68 /* The slab cache mutex protects the management structures during changes */
69 extern struct mutex slab_mutex
;
71 /* The list of all slab caches on the system */
72 extern struct list_head slab_caches
;
74 /* The slab cache that manages slab cache information */
75 extern struct kmem_cache
*kmem_cache
;
77 /* A table of kmalloc cache names and sizes */
78 extern const struct kmalloc_info_struct
{
84 /* Kmalloc array related functions */
85 void setup_kmalloc_cache_index_table(void);
86 void create_kmalloc_caches(slab_flags_t
);
88 /* Find the kmalloc slab corresponding for a certain size */
89 struct kmem_cache
*kmalloc_slab(size_t, gfp_t
);
93 /* Functions provided by the slab allocators */
94 int __kmem_cache_create(struct kmem_cache
*, slab_flags_t flags
);
96 struct kmem_cache
*create_kmalloc_cache(const char *name
, unsigned int size
,
97 slab_flags_t flags
, unsigned int useroffset
,
98 unsigned int usersize
);
99 extern void create_boot_cache(struct kmem_cache
*, const char *name
,
100 unsigned int size
, slab_flags_t flags
,
101 unsigned int useroffset
, unsigned int usersize
);
103 int slab_unmergeable(struct kmem_cache
*s
);
104 struct kmem_cache
*find_mergeable(unsigned size
, unsigned align
,
105 slab_flags_t flags
, const char *name
, void (*ctor
)(void *));
108 __kmem_cache_alias(const char *name
, unsigned int size
, unsigned int align
,
109 slab_flags_t flags
, void (*ctor
)(void *));
111 slab_flags_t
kmem_cache_flags(unsigned int object_size
,
112 slab_flags_t flags
, const char *name
,
113 void (*ctor
)(void *));
115 static inline struct kmem_cache
*
116 __kmem_cache_alias(const char *name
, unsigned int size
, unsigned int align
,
117 slab_flags_t flags
, void (*ctor
)(void *))
120 static inline slab_flags_t
kmem_cache_flags(unsigned int object_size
,
121 slab_flags_t flags
, const char *name
,
122 void (*ctor
)(void *))
129 /* Legal flag mask for kmem_cache_create(), for various configurations */
130 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
131 SLAB_CACHE_DMA32 | SLAB_PANIC | \
132 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
134 #if defined(CONFIG_DEBUG_SLAB)
135 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
136 #elif defined(CONFIG_SLUB_DEBUG)
137 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
138 SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
140 #define SLAB_DEBUG_FLAGS (0)
143 #if defined(CONFIG_SLAB)
144 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
145 SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
147 #elif defined(CONFIG_SLUB)
148 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
149 SLAB_TEMPORARY | SLAB_ACCOUNT)
151 #define SLAB_CACHE_FLAGS (0)
154 /* Common flags available with current configuration */
155 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
157 /* Common flags permitted for kmem_cache_create */
158 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
163 SLAB_CONSISTENCY_CHECKS | \
166 SLAB_RECLAIM_ACCOUNT | \
170 bool __kmem_cache_empty(struct kmem_cache
*);
171 int __kmem_cache_shutdown(struct kmem_cache
*);
172 void __kmem_cache_release(struct kmem_cache
*);
173 int __kmem_cache_shrink(struct kmem_cache
*);
174 void __kmemcg_cache_deactivate(struct kmem_cache
*s
);
175 void slab_kmem_cache_release(struct kmem_cache
*);
181 unsigned long active_objs
;
182 unsigned long num_objs
;
183 unsigned long active_slabs
;
184 unsigned long num_slabs
;
185 unsigned long shared_avail
;
187 unsigned int batchcount
;
189 unsigned int objects_per_slab
;
190 unsigned int cache_order
;
193 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
);
194 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
);
195 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
196 size_t count
, loff_t
*ppos
);
199 * Generic implementation of bulk operations
200 * These are useful for situations in which the allocator cannot
201 * perform optimizations. In that case segments of the object listed
202 * may be allocated or freed using these operations.
204 void __kmem_cache_free_bulk(struct kmem_cache
*, size_t, void **);
205 int __kmem_cache_alloc_bulk(struct kmem_cache
*, gfp_t
, size_t, void **);
207 #ifdef CONFIG_MEMCG_KMEM
209 /* List of all root caches. */
210 extern struct list_head slab_root_caches
;
211 #define root_caches_node memcg_params.__root_caches_node
214 * Iterate over all memcg caches of the given root cache. The caller must hold
217 #define for_each_memcg_cache(iter, root) \
218 list_for_each_entry(iter, &(root)->memcg_params.children, \
219 memcg_params.children_node)
221 static inline bool is_root_cache(struct kmem_cache
*s
)
223 return !s
->memcg_params
.root_cache
;
226 static inline bool slab_equal_or_root(struct kmem_cache
*s
,
227 struct kmem_cache
*p
)
229 return p
== s
|| p
== s
->memcg_params
.root_cache
;
233 * We use suffixes to the name in memcg because we can't have caches
234 * created in the system with the same name. But when we print them
235 * locally, better refer to them with the base name
237 static inline const char *cache_name(struct kmem_cache
*s
)
239 if (!is_root_cache(s
))
240 s
= s
->memcg_params
.root_cache
;
245 * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
246 * That said the caller must assure the memcg's cache won't go away by either
247 * taking a css reference to the owner cgroup, or holding the slab_mutex.
249 static inline struct kmem_cache
*
250 cache_from_memcg_idx(struct kmem_cache
*s
, int idx
)
252 struct kmem_cache
*cachep
;
253 struct memcg_cache_array
*arr
;
256 arr
= rcu_dereference(s
->memcg_params
.memcg_caches
);
259 * Make sure we will access the up-to-date value. The code updating
260 * memcg_caches issues a write barrier to match this (see
261 * memcg_create_kmem_cache()).
263 cachep
= READ_ONCE(arr
->entries
[idx
]);
269 static inline struct kmem_cache
*memcg_root_cache(struct kmem_cache
*s
)
271 if (is_root_cache(s
))
273 return s
->memcg_params
.root_cache
;
276 static __always_inline
int memcg_charge_slab(struct page
*page
,
277 gfp_t gfp
, int order
,
278 struct kmem_cache
*s
)
280 if (is_root_cache(s
))
282 return memcg_kmem_charge_memcg(page
, gfp
, order
, s
->memcg_params
.memcg
);
285 static __always_inline
void memcg_uncharge_slab(struct page
*page
, int order
,
286 struct kmem_cache
*s
)
288 memcg_kmem_uncharge(page
, order
);
291 extern void slab_init_memcg_params(struct kmem_cache
*);
292 extern void memcg_link_cache(struct kmem_cache
*s
);
293 extern void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache
*s
,
294 void (*deact_fn
)(struct kmem_cache
*));
296 #else /* CONFIG_MEMCG_KMEM */
298 /* If !memcg, all caches are root. */
299 #define slab_root_caches slab_caches
300 #define root_caches_node list
302 #define for_each_memcg_cache(iter, root) \
303 for ((void)(iter), (void)(root); 0; )
305 static inline bool is_root_cache(struct kmem_cache
*s
)
310 static inline bool slab_equal_or_root(struct kmem_cache
*s
,
311 struct kmem_cache
*p
)
316 static inline const char *cache_name(struct kmem_cache
*s
)
321 static inline struct kmem_cache
*
322 cache_from_memcg_idx(struct kmem_cache
*s
, int idx
)
327 static inline struct kmem_cache
*memcg_root_cache(struct kmem_cache
*s
)
332 static inline int memcg_charge_slab(struct page
*page
, gfp_t gfp
, int order
,
333 struct kmem_cache
*s
)
338 static inline void memcg_uncharge_slab(struct page
*page
, int order
,
339 struct kmem_cache
*s
)
343 static inline void slab_init_memcg_params(struct kmem_cache
*s
)
347 static inline void memcg_link_cache(struct kmem_cache
*s
)
351 #endif /* CONFIG_MEMCG_KMEM */
353 static inline struct kmem_cache
*cache_from_obj(struct kmem_cache
*s
, void *x
)
355 struct kmem_cache
*cachep
;
359 * When kmemcg is not being used, both assignments should return the
360 * same value. but we don't want to pay the assignment price in that
361 * case. If it is not compiled in, the compiler should be smart enough
362 * to not do even the assignment. In that case, slab_equal_or_root
363 * will also be a constant.
365 if (!memcg_kmem_enabled() &&
366 !unlikely(s
->flags
& SLAB_CONSISTENCY_CHECKS
))
369 page
= virt_to_head_page(x
);
370 cachep
= page
->slab_cache
;
371 if (slab_equal_or_root(cachep
, s
))
374 pr_err("%s: Wrong slab cache. %s but object is from %s\n",
375 __func__
, s
->name
, cachep
->name
);
380 static inline size_t slab_ksize(const struct kmem_cache
*s
)
383 return s
->object_size
;
385 #else /* CONFIG_SLUB */
386 # ifdef CONFIG_SLUB_DEBUG
388 * Debugging requires use of the padding between object
389 * and whatever may come after it.
391 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
392 return s
->object_size
;
394 if (s
->flags
& SLAB_KASAN
)
395 return s
->object_size
;
397 * If we have the need to store the freelist pointer
398 * back there or track user information then we can
399 * only use the space before that information.
401 if (s
->flags
& (SLAB_TYPESAFE_BY_RCU
| SLAB_STORE_USER
))
404 * Else we can use all the padding etc for the allocation
410 static inline struct kmem_cache
*slab_pre_alloc_hook(struct kmem_cache
*s
,
413 flags
&= gfp_allowed_mask
;
415 fs_reclaim_acquire(flags
);
416 fs_reclaim_release(flags
);
418 might_sleep_if(gfpflags_allow_blocking(flags
));
420 if (should_failslab(s
, flags
))
423 if (memcg_kmem_enabled() &&
424 ((flags
& __GFP_ACCOUNT
) || (s
->flags
& SLAB_ACCOUNT
)))
425 return memcg_kmem_get_cache(s
);
430 static inline void slab_post_alloc_hook(struct kmem_cache
*s
, gfp_t flags
,
431 size_t size
, void **p
)
435 flags
&= gfp_allowed_mask
;
436 for (i
= 0; i
< size
; i
++) {
437 p
[i
] = kasan_slab_alloc(s
, p
[i
], flags
);
438 /* As p[i] might get tagged, call kmemleak hook after KASAN. */
439 kmemleak_alloc_recursive(p
[i
], s
->object_size
, 1,
443 if (memcg_kmem_enabled())
444 memcg_kmem_put_cache(s
);
449 * The slab lists for all objects.
451 struct kmem_cache_node
{
452 spinlock_t list_lock
;
455 struct list_head slabs_partial
; /* partial list first, better asm code */
456 struct list_head slabs_full
;
457 struct list_head slabs_free
;
458 unsigned long total_slabs
; /* length of all slab lists */
459 unsigned long free_slabs
; /* length of free slab list only */
460 unsigned long free_objects
;
461 unsigned int free_limit
;
462 unsigned int colour_next
; /* Per-node cache coloring */
463 struct array_cache
*shared
; /* shared per node */
464 struct alien_cache
**alien
; /* on other nodes */
465 unsigned long next_reap
; /* updated without locking */
466 int free_touched
; /* updated without locking */
470 unsigned long nr_partial
;
471 struct list_head partial
;
472 #ifdef CONFIG_SLUB_DEBUG
473 atomic_long_t nr_slabs
;
474 atomic_long_t total_objects
;
475 struct list_head full
;
481 static inline struct kmem_cache_node
*get_node(struct kmem_cache
*s
, int node
)
483 return s
->node
[node
];
487 * Iterator over all nodes. The body will be executed for each node that has
488 * a kmem_cache_node structure allocated (which is true for all online nodes)
490 #define for_each_kmem_cache_node(__s, __node, __n) \
491 for (__node = 0; __node < nr_node_ids; __node++) \
492 if ((__n = get_node(__s, __node)))
496 void *slab_start(struct seq_file
*m
, loff_t
*pos
);
497 void *slab_next(struct seq_file
*m
, void *p
, loff_t
*pos
);
498 void slab_stop(struct seq_file
*m
, void *p
);
499 void *memcg_slab_start(struct seq_file
*m
, loff_t
*pos
);
500 void *memcg_slab_next(struct seq_file
*m
, void *p
, loff_t
*pos
);
501 void memcg_slab_stop(struct seq_file
*m
, void *p
);
502 int memcg_slab_show(struct seq_file
*m
, void *p
);
504 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
505 void dump_unreclaimable_slab(void);
507 static inline void dump_unreclaimable_slab(void)
512 void ___cache_free(struct kmem_cache
*cache
, void *x
, unsigned long addr
);
514 #ifdef CONFIG_SLAB_FREELIST_RANDOM
515 int cache_random_seq_create(struct kmem_cache
*cachep
, unsigned int count
,
517 void cache_random_seq_destroy(struct kmem_cache
*cachep
);
519 static inline int cache_random_seq_create(struct kmem_cache
*cachep
,
520 unsigned int count
, gfp_t gfp
)
524 static inline void cache_random_seq_destroy(struct kmem_cache
*cachep
) { }
525 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
527 #endif /* MM_SLAB_H */