1 /* SPDX-License-Identifier: GPL-2.0 */
5 #include <linux/reciprocal_div.h>
6 #include <linux/list_lru.h>
7 #include <linux/local_lock.h>
8 #include <linux/random.h>
9 #include <linux/kobject.h>
10 #include <linux/sched/mm.h>
11 #include <linux/memcontrol.h>
12 #include <linux/kfence.h>
13 #include <linux/kasan.h>
16 * Internal slab definitions
20 # ifdef system_has_cmpxchg128
21 # define system_has_freelist_aba() system_has_cmpxchg128()
22 # define try_cmpxchg_freelist try_cmpxchg128
24 #define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg128
25 typedef u128 freelist_full_t
;
26 #else /* CONFIG_64BIT */
27 # ifdef system_has_cmpxchg64
28 # define system_has_freelist_aba() system_has_cmpxchg64()
29 # define try_cmpxchg_freelist try_cmpxchg64
31 #define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg64
32 typedef u64 freelist_full_t
;
33 #endif /* CONFIG_64BIT */
35 #if defined(system_has_freelist_aba) && !defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
36 #undef system_has_freelist_aba
40 * Freelist pointer and counter to cmpxchg together, avoids the typical ABA
41 * problems with cmpxchg of just a pointer.
46 unsigned long counter
;
51 /* Reuses the bits in struct page */
53 unsigned long __page_flags
;
55 struct kmem_cache
*slab_cache
;
59 struct list_head slab_list
;
60 #ifdef CONFIG_SLUB_CPU_PARTIAL
63 int slabs
; /* Nr of slabs left */
67 /* Double-word boundary */
70 void *freelist
; /* first free object */
72 unsigned long counters
;
80 #ifdef system_has_freelist_aba
81 freelist_aba_t freelist_counter
;
85 struct rcu_head rcu_head
;
87 unsigned int __unused
;
89 atomic_t __page_refcount
;
91 unsigned long memcg_data
;
95 #define SLAB_MATCH(pg, sl) \
96 static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
97 SLAB_MATCH(flags
, __page_flags
);
98 SLAB_MATCH(compound_head
, slab_cache
); /* Ensure bit 0 is clear */
99 SLAB_MATCH(_refcount
, __page_refcount
);
101 SLAB_MATCH(memcg_data
, memcg_data
);
104 static_assert(sizeof(struct slab
) <= sizeof(struct page
));
105 #if defined(system_has_freelist_aba)
106 static_assert(IS_ALIGNED(offsetof(struct slab
, freelist
), sizeof(freelist_aba_t
)));
110 * folio_slab - Converts from folio to slab.
113 * Currently struct slab is a different representation of a folio where
114 * folio_test_slab() is true.
116 * Return: The slab which contains this folio.
118 #define folio_slab(folio) (_Generic((folio), \
119 const struct folio *: (const struct slab *)(folio), \
120 struct folio *: (struct slab *)(folio)))
123 * slab_folio - The folio allocated for a slab
126 * Slabs are allocated as folios that contain the individual objects and are
127 * using some fields in the first struct page of the folio - those fields are
128 * now accessed by struct slab. It is occasionally necessary to convert back to
129 * a folio in order to communicate with the rest of the mm. Please use this
130 * helper function instead of casting yourself, as the implementation may change
133 #define slab_folio(s) (_Generic((s), \
134 const struct slab *: (const struct folio *)s, \
135 struct slab *: (struct folio *)s))
138 * page_slab - Converts from first struct page to slab.
139 * @p: The first (either head of compound or single) page of slab.
141 * A temporary wrapper to convert struct page to struct slab in situations where
142 * we know the page is the compound head, or single order-0 page.
144 * Long-term ideally everything would work with struct slab directly or go
145 * through folio to struct slab.
147 * Return: The slab which contains this page
149 #define page_slab(p) (_Generic((p), \
150 const struct page *: (const struct slab *)(p), \
151 struct page *: (struct slab *)(p)))
154 * slab_page - The first struct page allocated for a slab
157 * A convenience wrapper for converting slab to the first struct page of the
158 * underlying folio, to communicate with code not yet converted to folio or
161 #define slab_page(s) folio_page(slab_folio(s), 0)
164 * If network-based swap is enabled, sl*b must keep track of whether pages
165 * were allocated from pfmemalloc reserves.
167 static inline bool slab_test_pfmemalloc(const struct slab
*slab
)
169 return folio_test_active((struct folio
*)slab_folio(slab
));
172 static inline void slab_set_pfmemalloc(struct slab
*slab
)
174 folio_set_active(slab_folio(slab
));
177 static inline void slab_clear_pfmemalloc(struct slab
*slab
)
179 folio_clear_active(slab_folio(slab
));
182 static inline void __slab_clear_pfmemalloc(struct slab
*slab
)
184 __folio_clear_active(slab_folio(slab
));
187 static inline void *slab_address(const struct slab
*slab
)
189 return folio_address(slab_folio(slab
));
192 static inline int slab_nid(const struct slab
*slab
)
194 return folio_nid(slab_folio(slab
));
197 static inline pg_data_t
*slab_pgdat(const struct slab
*slab
)
199 return folio_pgdat(slab_folio(slab
));
202 static inline struct slab
*virt_to_slab(const void *addr
)
204 struct folio
*folio
= virt_to_folio(addr
);
206 if (!folio_test_slab(folio
))
209 return folio_slab(folio
);
212 static inline int slab_order(const struct slab
*slab
)
214 return folio_order((struct folio
*)slab_folio(slab
));
217 static inline size_t slab_size(const struct slab
*slab
)
219 return PAGE_SIZE
<< slab_order(slab
);
222 #ifdef CONFIG_SLUB_CPU_PARTIAL
223 #define slub_percpu_partial(c) ((c)->partial)
225 #define slub_set_percpu_partial(c, p) \
227 slub_percpu_partial(c) = (p)->next; \
230 #define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c))
232 #define slub_percpu_partial(c) NULL
234 #define slub_set_percpu_partial(c, p)
236 #define slub_percpu_partial_read_once(c) NULL
237 #endif // CONFIG_SLUB_CPU_PARTIAL
240 * Word size structure that can be atomically updated or read and that
241 * contains both the order and the number of objects that a slab of the
242 * given order would contain.
244 struct kmem_cache_order_objects
{
249 * Slab cache management.
252 #ifndef CONFIG_SLUB_TINY
253 struct kmem_cache_cpu __percpu
*cpu_slab
;
255 /* Used for retrieving partial slabs, etc. */
257 unsigned long min_partial
;
258 unsigned int size
; /* Object size including metadata */
259 unsigned int object_size
; /* Object size without metadata */
260 struct reciprocal_value reciprocal_size
;
261 unsigned int offset
; /* Free pointer offset */
262 #ifdef CONFIG_SLUB_CPU_PARTIAL
263 /* Number of per cpu partial objects to keep around */
264 unsigned int cpu_partial
;
265 /* Number of per cpu partial slabs to keep around */
266 unsigned int cpu_partial_slabs
;
268 struct kmem_cache_order_objects oo
;
270 /* Allocation and freeing of slabs */
271 struct kmem_cache_order_objects min
;
272 gfp_t allocflags
; /* gfp flags to use on each alloc */
273 int refcount
; /* Refcount for slab cache destroy */
274 void (*ctor
)(void *object
); /* Object constructor */
275 unsigned int inuse
; /* Offset to metadata */
276 unsigned int align
; /* Alignment */
277 unsigned int red_left_pad
; /* Left redzone padding size */
278 const char *name
; /* Name (only for display!) */
279 struct list_head list
; /* List of slab caches */
281 struct kobject kobj
; /* For sysfs */
283 #ifdef CONFIG_SLAB_FREELIST_HARDENED
284 unsigned long random
;
289 * Defragmentation by allocating from a remote node.
291 unsigned int remote_node_defrag_ratio
;
294 #ifdef CONFIG_SLAB_FREELIST_RANDOM
295 unsigned int *random_seq
;
298 #ifdef CONFIG_KASAN_GENERIC
299 struct kasan_cache kasan_info
;
302 #ifdef CONFIG_HARDENED_USERCOPY
303 unsigned int useroffset
; /* Usercopy region offset */
304 unsigned int usersize
; /* Usercopy region size */
307 struct kmem_cache_node
*node
[MAX_NUMNODES
];
310 #if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
311 #define SLAB_SUPPORTS_SYSFS
312 void sysfs_slab_unlink(struct kmem_cache
*s
);
313 void sysfs_slab_release(struct kmem_cache
*s
);
315 static inline void sysfs_slab_unlink(struct kmem_cache
*s
) { }
316 static inline void sysfs_slab_release(struct kmem_cache
*s
) { }
319 void *fixup_red_left(struct kmem_cache
*s
, void *p
);
321 static inline void *nearest_obj(struct kmem_cache
*cache
,
322 const struct slab
*slab
, void *x
)
324 void *object
= x
- (x
- slab_address(slab
)) % cache
->size
;
325 void *last_object
= slab_address(slab
) +
326 (slab
->objects
- 1) * cache
->size
;
327 void *result
= (unlikely(object
> last_object
)) ? last_object
: object
;
329 result
= fixup_red_left(cache
, result
);
333 /* Determine object index from a given position */
334 static inline unsigned int __obj_to_index(const struct kmem_cache
*cache
,
335 void *addr
, void *obj
)
337 return reciprocal_divide(kasan_reset_tag(obj
) - addr
,
338 cache
->reciprocal_size
);
341 static inline unsigned int obj_to_index(const struct kmem_cache
*cache
,
342 const struct slab
*slab
, void *obj
)
344 if (is_kfence_address(obj
))
346 return __obj_to_index(cache
, slab_address(slab
), obj
);
349 static inline int objs_per_slab(const struct kmem_cache
*cache
,
350 const struct slab
*slab
)
352 return slab
->objects
;
356 * State of the slab allocator.
358 * This is used to describe the states of the allocator during bootup.
359 * Allocators use this to gradually bootstrap themselves. Most allocators
360 * have the problem that the structures used for managing slab caches are
361 * allocated from slab caches themselves.
364 DOWN
, /* No slab functionality yet */
365 PARTIAL
, /* SLUB: kmem_cache_node available */
366 UP
, /* Slab caches usable but not all extras yet */
367 FULL
/* Everything is working */
370 extern enum slab_state slab_state
;
372 /* The slab cache mutex protects the management structures during changes */
373 extern struct mutex slab_mutex
;
375 /* The list of all slab caches on the system */
376 extern struct list_head slab_caches
;
378 /* The slab cache that manages slab cache information */
379 extern struct kmem_cache
*kmem_cache
;
381 /* A table of kmalloc cache names and sizes */
382 extern const struct kmalloc_info_struct
{
383 const char *name
[NR_KMALLOC_TYPES
];
387 /* Kmalloc array related functions */
388 void setup_kmalloc_cache_index_table(void);
389 void create_kmalloc_caches(void);
391 extern u8 kmalloc_size_index
[24];
393 static inline unsigned int size_index_elem(unsigned int bytes
)
395 return (bytes
- 1) / 8;
399 * Find the kmem_cache structure that serves a given size of
402 * This assumes size is larger than zero and not larger than
403 * KMALLOC_MAX_CACHE_SIZE and the caller must check that.
405 static inline struct kmem_cache
*
406 kmalloc_slab(size_t size
, gfp_t flags
, unsigned long caller
)
411 index
= kmalloc_size_index
[size_index_elem(size
)];
413 index
= fls(size
- 1);
415 return kmalloc_caches
[kmalloc_type(flags
, caller
)][index
];
418 gfp_t
kmalloc_fix_flags(gfp_t flags
);
420 /* Functions provided by the slab allocators */
421 int __kmem_cache_create(struct kmem_cache
*, slab_flags_t flags
);
423 void __init
kmem_cache_init(void);
424 extern void create_boot_cache(struct kmem_cache
*, const char *name
,
425 unsigned int size
, slab_flags_t flags
,
426 unsigned int useroffset
, unsigned int usersize
);
428 int slab_unmergeable(struct kmem_cache
*s
);
429 struct kmem_cache
*find_mergeable(unsigned size
, unsigned align
,
430 slab_flags_t flags
, const char *name
, void (*ctor
)(void *));
432 __kmem_cache_alias(const char *name
, unsigned int size
, unsigned int align
,
433 slab_flags_t flags
, void (*ctor
)(void *));
435 slab_flags_t
kmem_cache_flags(slab_flags_t flags
, const char *name
);
437 static inline bool is_kmalloc_cache(struct kmem_cache
*s
)
439 return (s
->flags
& SLAB_KMALLOC
);
442 /* Legal flag mask for kmem_cache_create(), for various configurations */
443 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
444 SLAB_CACHE_DMA32 | SLAB_PANIC | \
445 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
447 #ifdef CONFIG_SLUB_DEBUG
448 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
449 SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
451 #define SLAB_DEBUG_FLAGS (0)
454 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
455 SLAB_TEMPORARY | SLAB_ACCOUNT | \
456 SLAB_NO_USER_FLAGS | SLAB_KMALLOC | SLAB_NO_MERGE)
458 /* Common flags available with current configuration */
459 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
461 /* Common flags permitted for kmem_cache_create */
462 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
467 SLAB_CONSISTENCY_CHECKS | \
469 SLAB_RECLAIM_ACCOUNT | \
476 bool __kmem_cache_empty(struct kmem_cache
*);
477 int __kmem_cache_shutdown(struct kmem_cache
*);
478 void __kmem_cache_release(struct kmem_cache
*);
479 int __kmem_cache_shrink(struct kmem_cache
*);
480 void slab_kmem_cache_release(struct kmem_cache
*);
486 unsigned long active_objs
;
487 unsigned long num_objs
;
488 unsigned long active_slabs
;
489 unsigned long num_slabs
;
490 unsigned long shared_avail
;
492 unsigned int batchcount
;
494 unsigned int objects_per_slab
;
495 unsigned int cache_order
;
498 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
);
499 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
);
500 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
501 size_t count
, loff_t
*ppos
);
503 #ifdef CONFIG_SLUB_DEBUG
504 #ifdef CONFIG_SLUB_DEBUG_ON
505 DECLARE_STATIC_KEY_TRUE(slub_debug_enabled
);
507 DECLARE_STATIC_KEY_FALSE(slub_debug_enabled
);
509 extern void print_tracking(struct kmem_cache
*s
, void *object
);
510 long validate_slab_cache(struct kmem_cache
*s
);
511 static inline bool __slub_debug_enabled(void)
513 return static_branch_unlikely(&slub_debug_enabled
);
516 static inline void print_tracking(struct kmem_cache
*s
, void *object
)
519 static inline bool __slub_debug_enabled(void)
526 * Returns true if any of the specified slab_debug flags is enabled for the
527 * cache. Use only for flags parsed by setup_slub_debug() as it also enables
530 static inline bool kmem_cache_debug_flags(struct kmem_cache
*s
, slab_flags_t flags
)
532 if (IS_ENABLED(CONFIG_SLUB_DEBUG
))
533 VM_WARN_ON_ONCE(!(flags
& SLAB_DEBUG_FLAGS
));
534 if (__slub_debug_enabled())
535 return s
->flags
& flags
;
539 #ifdef CONFIG_MEMCG_KMEM
541 * slab_objcgs - get the object cgroups vector associated with a slab
542 * @slab: a pointer to the slab struct
544 * Returns a pointer to the object cgroups vector associated with the slab,
545 * or NULL if no such vector has been associated yet.
547 static inline struct obj_cgroup
**slab_objcgs(struct slab
*slab
)
549 unsigned long memcg_data
= READ_ONCE(slab
->memcg_data
);
551 VM_BUG_ON_PAGE(memcg_data
&& !(memcg_data
& MEMCG_DATA_OBJCGS
),
553 VM_BUG_ON_PAGE(memcg_data
& MEMCG_DATA_KMEM
, slab_page(slab
));
555 return (struct obj_cgroup
**)(memcg_data
& ~MEMCG_DATA_FLAGS_MASK
);
558 int memcg_alloc_slab_cgroups(struct slab
*slab
, struct kmem_cache
*s
,
559 gfp_t gfp
, bool new_slab
);
560 void mod_objcg_state(struct obj_cgroup
*objcg
, struct pglist_data
*pgdat
,
561 enum node_stat_item idx
, int nr
);
562 #else /* CONFIG_MEMCG_KMEM */
563 static inline struct obj_cgroup
**slab_objcgs(struct slab
*slab
)
568 static inline int memcg_alloc_slab_cgroups(struct slab
*slab
,
569 struct kmem_cache
*s
, gfp_t gfp
,
574 #endif /* CONFIG_MEMCG_KMEM */
576 size_t __ksize(const void *objp
);
578 static inline size_t slab_ksize(const struct kmem_cache
*s
)
580 #ifdef CONFIG_SLUB_DEBUG
582 * Debugging requires use of the padding between object
583 * and whatever may come after it.
585 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
586 return s
->object_size
;
588 if (s
->flags
& SLAB_KASAN
)
589 return s
->object_size
;
591 * If we have the need to store the freelist pointer
592 * back there or track user information then we can
593 * only use the space before that information.
595 if (s
->flags
& (SLAB_TYPESAFE_BY_RCU
| SLAB_STORE_USER
))
598 * Else we can use all the padding etc for the allocation
603 #ifdef CONFIG_SLUB_DEBUG
604 void dump_unreclaimable_slab(void);
606 static inline void dump_unreclaimable_slab(void)
611 void ___cache_free(struct kmem_cache
*cache
, void *x
, unsigned long addr
);
613 #ifdef CONFIG_SLAB_FREELIST_RANDOM
614 int cache_random_seq_create(struct kmem_cache
*cachep
, unsigned int count
,
616 void cache_random_seq_destroy(struct kmem_cache
*cachep
);
618 static inline int cache_random_seq_create(struct kmem_cache
*cachep
,
619 unsigned int count
, gfp_t gfp
)
623 static inline void cache_random_seq_destroy(struct kmem_cache
*cachep
) { }
624 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
626 static inline bool slab_want_init_on_alloc(gfp_t flags
, struct kmem_cache
*c
)
628 if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON
,
632 if (c
->flags
& (SLAB_TYPESAFE_BY_RCU
| SLAB_POISON
))
633 return flags
& __GFP_ZERO
;
636 return flags
& __GFP_ZERO
;
639 static inline bool slab_want_init_on_free(struct kmem_cache
*c
)
641 if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON
,
644 (c
->flags
& (SLAB_TYPESAFE_BY_RCU
| SLAB_POISON
)));
648 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
649 void debugfs_slab_release(struct kmem_cache
*);
651 static inline void debugfs_slab_release(struct kmem_cache
*s
) { }
655 #define KS_ADDRS_COUNT 16
656 struct kmem_obj_info
{
658 struct slab
*kp_slab
;
660 unsigned long kp_data_offset
;
661 struct kmem_cache
*kp_slab_cache
;
663 void *kp_stack
[KS_ADDRS_COUNT
];
664 void *kp_free_stack
[KS_ADDRS_COUNT
];
666 void __kmem_obj_info(struct kmem_obj_info
*kpp
, void *object
, struct slab
*slab
);
669 void __check_heap_object(const void *ptr
, unsigned long n
,
670 const struct slab
*slab
, bool to_user
);
672 #ifdef CONFIG_SLUB_DEBUG
673 void skip_orig_size_check(struct kmem_cache
*s
, const void *object
);
676 #endif /* MM_SLAB_H */