1 // SPDX-License-Identifier: GPL-2.0
3 * Slab allocator functions that are independent of the allocator strategy
5 * (C) 2012 Christoph Lameter <cl@linux.com>
7 #include <linux/slab.h>
10 #include <linux/poison.h>
11 #include <linux/interrupt.h>
12 #include <linux/memory.h>
13 #include <linux/cache.h>
14 #include <linux/compiler.h>
15 #include <linux/module.h>
16 #include <linux/cpu.h>
17 #include <linux/uaccess.h>
18 #include <linux/seq_file.h>
19 #include <linux/proc_fs.h>
20 #include <linux/debugfs.h>
21 #include <asm/cacheflush.h>
22 #include <asm/tlbflush.h>
24 #include <linux/memcontrol.h>
26 #define CREATE_TRACE_POINTS
27 #include <trace/events/kmem.h>
31 enum slab_state slab_state
;
32 LIST_HEAD(slab_caches
);
33 DEFINE_MUTEX(slab_mutex
);
34 struct kmem_cache
*kmem_cache
;
36 #ifdef CONFIG_HARDENED_USERCOPY
37 bool usercopy_fallback __ro_after_init
=
38 IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK
);
39 module_param(usercopy_fallback
, bool, 0400);
40 MODULE_PARM_DESC(usercopy_fallback
,
41 "WARN instead of reject usercopy whitelist violations");
44 static LIST_HEAD(slab_caches_to_rcu_destroy
);
45 static void slab_caches_to_rcu_destroy_workfn(struct work_struct
*work
);
46 static DECLARE_WORK(slab_caches_to_rcu_destroy_work
,
47 slab_caches_to_rcu_destroy_workfn
);
50 * Set of flags that will prevent slab merging
52 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
53 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
54 SLAB_FAILSLAB | SLAB_KASAN)
56 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
57 SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
60 * Merge control. If this is set then no merging of slab caches will occur.
62 static bool slab_nomerge
= !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT
);
64 static int __init
setup_slab_nomerge(char *str
)
71 __setup_param("slub_nomerge", slub_nomerge
, setup_slab_nomerge
, 0);
74 __setup("slab_nomerge", setup_slab_nomerge
);
77 * Determine the size of a slab object
79 unsigned int kmem_cache_size(struct kmem_cache
*s
)
81 return s
->object_size
;
83 EXPORT_SYMBOL(kmem_cache_size
);
85 #ifdef CONFIG_DEBUG_VM
86 static int kmem_cache_sanity_check(const char *name
, unsigned int size
)
88 if (!name
|| in_interrupt() || size
> KMALLOC_MAX_SIZE
) {
89 pr_err("kmem_cache_create(%s) integrity check failed\n", name
);
93 WARN_ON(strchr(name
, ' ')); /* It confuses parsers */
97 static inline int kmem_cache_sanity_check(const char *name
, unsigned int size
)
103 void __kmem_cache_free_bulk(struct kmem_cache
*s
, size_t nr
, void **p
)
107 for (i
= 0; i
< nr
; i
++) {
109 kmem_cache_free(s
, p
[i
]);
115 int __kmem_cache_alloc_bulk(struct kmem_cache
*s
, gfp_t flags
, size_t nr
,
120 for (i
= 0; i
< nr
; i
++) {
121 void *x
= p
[i
] = kmem_cache_alloc(s
, flags
);
123 __kmem_cache_free_bulk(s
, i
, p
);
130 #ifdef CONFIG_MEMCG_KMEM
132 LIST_HEAD(slab_root_caches
);
133 static DEFINE_SPINLOCK(memcg_kmem_wq_lock
);
135 static void kmemcg_cache_shutdown(struct percpu_ref
*percpu_ref
);
137 void slab_init_memcg_params(struct kmem_cache
*s
)
139 s
->memcg_params
.root_cache
= NULL
;
140 RCU_INIT_POINTER(s
->memcg_params
.memcg_caches
, NULL
);
141 INIT_LIST_HEAD(&s
->memcg_params
.children
);
142 s
->memcg_params
.dying
= false;
145 static int init_memcg_params(struct kmem_cache
*s
,
146 struct kmem_cache
*root_cache
)
148 struct memcg_cache_array
*arr
;
151 int ret
= percpu_ref_init(&s
->memcg_params
.refcnt
,
152 kmemcg_cache_shutdown
,
157 s
->memcg_params
.root_cache
= root_cache
;
158 INIT_LIST_HEAD(&s
->memcg_params
.children_node
);
159 INIT_LIST_HEAD(&s
->memcg_params
.kmem_caches_node
);
163 slab_init_memcg_params(s
);
165 if (!memcg_nr_cache_ids
)
168 arr
= kvzalloc(sizeof(struct memcg_cache_array
) +
169 memcg_nr_cache_ids
* sizeof(void *),
174 RCU_INIT_POINTER(s
->memcg_params
.memcg_caches
, arr
);
178 static void destroy_memcg_params(struct kmem_cache
*s
)
180 if (is_root_cache(s
)) {
181 kvfree(rcu_access_pointer(s
->memcg_params
.memcg_caches
));
183 mem_cgroup_put(s
->memcg_params
.memcg
);
184 WRITE_ONCE(s
->memcg_params
.memcg
, NULL
);
185 percpu_ref_exit(&s
->memcg_params
.refcnt
);
189 static void free_memcg_params(struct rcu_head
*rcu
)
191 struct memcg_cache_array
*old
;
193 old
= container_of(rcu
, struct memcg_cache_array
, rcu
);
197 static int update_memcg_params(struct kmem_cache
*s
, int new_array_size
)
199 struct memcg_cache_array
*old
, *new;
201 new = kvzalloc(sizeof(struct memcg_cache_array
) +
202 new_array_size
* sizeof(void *), GFP_KERNEL
);
206 old
= rcu_dereference_protected(s
->memcg_params
.memcg_caches
,
207 lockdep_is_held(&slab_mutex
));
209 memcpy(new->entries
, old
->entries
,
210 memcg_nr_cache_ids
* sizeof(void *));
212 rcu_assign_pointer(s
->memcg_params
.memcg_caches
, new);
214 call_rcu(&old
->rcu
, free_memcg_params
);
218 int memcg_update_all_caches(int num_memcgs
)
220 struct kmem_cache
*s
;
223 mutex_lock(&slab_mutex
);
224 list_for_each_entry(s
, &slab_root_caches
, root_caches_node
) {
225 ret
= update_memcg_params(s
, num_memcgs
);
227 * Instead of freeing the memory, we'll just leave the caches
228 * up to this point in an updated state.
233 mutex_unlock(&slab_mutex
);
237 void memcg_link_cache(struct kmem_cache
*s
, struct mem_cgroup
*memcg
)
239 if (is_root_cache(s
)) {
240 list_add(&s
->root_caches_node
, &slab_root_caches
);
242 css_get(&memcg
->css
);
243 s
->memcg_params
.memcg
= memcg
;
244 list_add(&s
->memcg_params
.children_node
,
245 &s
->memcg_params
.root_cache
->memcg_params
.children
);
246 list_add(&s
->memcg_params
.kmem_caches_node
,
247 &s
->memcg_params
.memcg
->kmem_caches
);
251 static void memcg_unlink_cache(struct kmem_cache
*s
)
253 if (is_root_cache(s
)) {
254 list_del(&s
->root_caches_node
);
256 list_del(&s
->memcg_params
.children_node
);
257 list_del(&s
->memcg_params
.kmem_caches_node
);
261 static inline int init_memcg_params(struct kmem_cache
*s
,
262 struct kmem_cache
*root_cache
)
267 static inline void destroy_memcg_params(struct kmem_cache
*s
)
271 static inline void memcg_unlink_cache(struct kmem_cache
*s
)
274 #endif /* CONFIG_MEMCG_KMEM */
277 * Figure out what the alignment of the objects will be given a set of
278 * flags, a user specified alignment and the size of the objects.
280 static unsigned int calculate_alignment(slab_flags_t flags
,
281 unsigned int align
, unsigned int size
)
284 * If the user wants hardware cache aligned objects then follow that
285 * suggestion if the object is sufficiently large.
287 * The hardware cache alignment cannot override the specified
288 * alignment though. If that is greater then use it.
290 if (flags
& SLAB_HWCACHE_ALIGN
) {
293 ralign
= cache_line_size();
294 while (size
<= ralign
/ 2)
296 align
= max(align
, ralign
);
299 if (align
< ARCH_SLAB_MINALIGN
)
300 align
= ARCH_SLAB_MINALIGN
;
302 return ALIGN(align
, sizeof(void *));
306 * Find a mergeable slab cache
308 int slab_unmergeable(struct kmem_cache
*s
)
310 if (slab_nomerge
|| (s
->flags
& SLAB_NEVER_MERGE
))
313 if (!is_root_cache(s
))
323 * We may have set a slab to be unmergeable during bootstrap.
331 struct kmem_cache
*find_mergeable(unsigned int size
, unsigned int align
,
332 slab_flags_t flags
, const char *name
, void (*ctor
)(void *))
334 struct kmem_cache
*s
;
342 size
= ALIGN(size
, sizeof(void *));
343 align
= calculate_alignment(flags
, align
, size
);
344 size
= ALIGN(size
, align
);
345 flags
= kmem_cache_flags(size
, flags
, name
, NULL
);
347 if (flags
& SLAB_NEVER_MERGE
)
350 list_for_each_entry_reverse(s
, &slab_root_caches
, root_caches_node
) {
351 if (slab_unmergeable(s
))
357 if ((flags
& SLAB_MERGE_SAME
) != (s
->flags
& SLAB_MERGE_SAME
))
360 * Check if alignment is compatible.
361 * Courtesy of Adrian Drzewiecki
363 if ((s
->size
& ~(align
- 1)) != s
->size
)
366 if (s
->size
- size
>= sizeof(void *))
369 if (IS_ENABLED(CONFIG_SLAB
) && align
&&
370 (align
> s
->align
|| s
->align
% align
))
378 static struct kmem_cache
*create_cache(const char *name
,
379 unsigned int object_size
, unsigned int align
,
380 slab_flags_t flags
, unsigned int useroffset
,
381 unsigned int usersize
, void (*ctor
)(void *),
382 struct mem_cgroup
*memcg
, struct kmem_cache
*root_cache
)
384 struct kmem_cache
*s
;
387 if (WARN_ON(useroffset
+ usersize
> object_size
))
388 useroffset
= usersize
= 0;
391 s
= kmem_cache_zalloc(kmem_cache
, GFP_KERNEL
);
396 s
->size
= s
->object_size
= object_size
;
399 s
->useroffset
= useroffset
;
400 s
->usersize
= usersize
;
402 err
= init_memcg_params(s
, root_cache
);
406 err
= __kmem_cache_create(s
, flags
);
411 list_add(&s
->list
, &slab_caches
);
412 memcg_link_cache(s
, memcg
);
419 destroy_memcg_params(s
);
420 kmem_cache_free(kmem_cache
, s
);
425 * kmem_cache_create_usercopy - Create a cache with a region suitable
426 * for copying to userspace
427 * @name: A string which is used in /proc/slabinfo to identify this cache.
428 * @size: The size of objects to be created in this cache.
429 * @align: The required alignment for the objects.
431 * @useroffset: Usercopy region offset
432 * @usersize: Usercopy region size
433 * @ctor: A constructor for the objects.
435 * Cannot be called within a interrupt, but can be interrupted.
436 * The @ctor is run when new pages are allocated by the cache.
440 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
441 * to catch references to uninitialised memory.
443 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
444 * for buffer overruns.
446 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
447 * cacheline. This can be beneficial if you're counting cycles as closely
450 * Return: a pointer to the cache on success, NULL on failure.
453 kmem_cache_create_usercopy(const char *name
,
454 unsigned int size
, unsigned int align
,
456 unsigned int useroffset
, unsigned int usersize
,
457 void (*ctor
)(void *))
459 struct kmem_cache
*s
= NULL
;
460 const char *cache_name
;
465 memcg_get_cache_ids();
467 mutex_lock(&slab_mutex
);
469 err
= kmem_cache_sanity_check(name
, size
);
474 /* Refuse requests with allocator specific flags */
475 if (flags
& ~SLAB_FLAGS_PERMITTED
) {
481 * Some allocators will constraint the set of valid flags to a subset
482 * of all flags. We expect them to define CACHE_CREATE_MASK in this
483 * case, and we'll just provide them with a sanitized version of the
486 flags
&= CACHE_CREATE_MASK
;
488 /* Fail closed on bad usersize of useroffset values. */
489 if (WARN_ON(!usersize
&& useroffset
) ||
490 WARN_ON(size
< usersize
|| size
- usersize
< useroffset
))
491 usersize
= useroffset
= 0;
494 s
= __kmem_cache_alias(name
, size
, align
, flags
, ctor
);
498 cache_name
= kstrdup_const(name
, GFP_KERNEL
);
504 s
= create_cache(cache_name
, size
,
505 calculate_alignment(flags
, align
, size
),
506 flags
, useroffset
, usersize
, ctor
, NULL
, NULL
);
509 kfree_const(cache_name
);
513 mutex_unlock(&slab_mutex
);
515 memcg_put_cache_ids();
520 if (flags
& SLAB_PANIC
)
521 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
524 pr_warn("kmem_cache_create(%s) failed with error %d\n",
532 EXPORT_SYMBOL(kmem_cache_create_usercopy
);
535 * kmem_cache_create - Create a cache.
536 * @name: A string which is used in /proc/slabinfo to identify this cache.
537 * @size: The size of objects to be created in this cache.
538 * @align: The required alignment for the objects.
540 * @ctor: A constructor for the objects.
542 * Cannot be called within a interrupt, but can be interrupted.
543 * The @ctor is run when new pages are allocated by the cache.
547 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
548 * to catch references to uninitialised memory.
550 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
551 * for buffer overruns.
553 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
554 * cacheline. This can be beneficial if you're counting cycles as closely
557 * Return: a pointer to the cache on success, NULL on failure.
560 kmem_cache_create(const char *name
, unsigned int size
, unsigned int align
,
561 slab_flags_t flags
, void (*ctor
)(void *))
563 return kmem_cache_create_usercopy(name
, size
, align
, flags
, 0, 0,
566 EXPORT_SYMBOL(kmem_cache_create
);
568 static void slab_caches_to_rcu_destroy_workfn(struct work_struct
*work
)
570 LIST_HEAD(to_destroy
);
571 struct kmem_cache
*s
, *s2
;
574 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
575 * @slab_caches_to_rcu_destroy list. The slab pages are freed
576 * through RCU and and the associated kmem_cache are dereferenced
577 * while freeing the pages, so the kmem_caches should be freed only
578 * after the pending RCU operations are finished. As rcu_barrier()
579 * is a pretty slow operation, we batch all pending destructions
582 mutex_lock(&slab_mutex
);
583 list_splice_init(&slab_caches_to_rcu_destroy
, &to_destroy
);
584 mutex_unlock(&slab_mutex
);
586 if (list_empty(&to_destroy
))
591 list_for_each_entry_safe(s
, s2
, &to_destroy
, list
) {
592 #ifdef SLAB_SUPPORTS_SYSFS
593 sysfs_slab_release(s
);
595 slab_kmem_cache_release(s
);
600 static int shutdown_cache(struct kmem_cache
*s
)
602 /* free asan quarantined objects */
603 kasan_cache_shutdown(s
);
605 if (__kmem_cache_shutdown(s
) != 0)
608 memcg_unlink_cache(s
);
611 if (s
->flags
& SLAB_TYPESAFE_BY_RCU
) {
612 #ifdef SLAB_SUPPORTS_SYSFS
613 sysfs_slab_unlink(s
);
615 list_add_tail(&s
->list
, &slab_caches_to_rcu_destroy
);
616 schedule_work(&slab_caches_to_rcu_destroy_work
);
618 #ifdef SLAB_SUPPORTS_SYSFS
619 sysfs_slab_unlink(s
);
620 sysfs_slab_release(s
);
622 slab_kmem_cache_release(s
);
629 #ifdef CONFIG_MEMCG_KMEM
631 * memcg_create_kmem_cache - Create a cache for a memory cgroup.
632 * @memcg: The memory cgroup the new cache is for.
633 * @root_cache: The parent of the new cache.
635 * This function attempts to create a kmem cache that will serve allocation
636 * requests going from @memcg to @root_cache. The new cache inherits properties
639 void memcg_create_kmem_cache(struct mem_cgroup
*memcg
,
640 struct kmem_cache
*root_cache
)
642 static char memcg_name_buf
[NAME_MAX
+ 1]; /* protected by slab_mutex */
643 struct cgroup_subsys_state
*css
= &memcg
->css
;
644 struct memcg_cache_array
*arr
;
645 struct kmem_cache
*s
= NULL
;
652 mutex_lock(&slab_mutex
);
655 * The memory cgroup could have been offlined while the cache
656 * creation work was pending.
658 if (memcg
->kmem_state
!= KMEM_ONLINE
)
661 idx
= memcg_cache_id(memcg
);
662 arr
= rcu_dereference_protected(root_cache
->memcg_params
.memcg_caches
,
663 lockdep_is_held(&slab_mutex
));
666 * Since per-memcg caches are created asynchronously on first
667 * allocation (see memcg_kmem_get_cache()), several threads can try to
668 * create the same cache, but only one of them may succeed.
670 if (arr
->entries
[idx
])
673 cgroup_name(css
->cgroup
, memcg_name_buf
, sizeof(memcg_name_buf
));
674 cache_name
= kasprintf(GFP_KERNEL
, "%s(%llu:%s)", root_cache
->name
,
675 css
->serial_nr
, memcg_name_buf
);
679 s
= create_cache(cache_name
, root_cache
->object_size
,
681 root_cache
->flags
& CACHE_CREATE_MASK
,
682 root_cache
->useroffset
, root_cache
->usersize
,
683 root_cache
->ctor
, memcg
, root_cache
);
685 * If we could not create a memcg cache, do not complain, because
686 * that's not critical at all as we can always proceed with the root
695 * Since readers won't lock (see memcg_kmem_get_cache()), we need a
696 * barrier here to ensure nobody will see the kmem_cache partially
700 arr
->entries
[idx
] = s
;
703 mutex_unlock(&slab_mutex
);
709 static void kmemcg_workfn(struct work_struct
*work
)
711 struct kmem_cache
*s
= container_of(work
, struct kmem_cache
,
717 mutex_lock(&slab_mutex
);
718 s
->memcg_params
.work_fn(s
);
719 mutex_unlock(&slab_mutex
);
725 static void kmemcg_rcufn(struct rcu_head
*head
)
727 struct kmem_cache
*s
= container_of(head
, struct kmem_cache
,
728 memcg_params
.rcu_head
);
731 * We need to grab blocking locks. Bounce to ->work. The
732 * work item shares the space with the RCU head and can't be
733 * initialized eariler.
735 INIT_WORK(&s
->memcg_params
.work
, kmemcg_workfn
);
736 queue_work(memcg_kmem_cache_wq
, &s
->memcg_params
.work
);
739 static void kmemcg_cache_shutdown_fn(struct kmem_cache
*s
)
741 WARN_ON(shutdown_cache(s
));
744 static void kmemcg_cache_shutdown(struct percpu_ref
*percpu_ref
)
746 struct kmem_cache
*s
= container_of(percpu_ref
, struct kmem_cache
,
747 memcg_params
.refcnt
);
750 spin_lock_irqsave(&memcg_kmem_wq_lock
, flags
);
751 if (s
->memcg_params
.root_cache
->memcg_params
.dying
)
754 s
->memcg_params
.work_fn
= kmemcg_cache_shutdown_fn
;
755 INIT_WORK(&s
->memcg_params
.work
, kmemcg_workfn
);
756 queue_work(memcg_kmem_cache_wq
, &s
->memcg_params
.work
);
759 spin_unlock_irqrestore(&memcg_kmem_wq_lock
, flags
);
762 static void kmemcg_cache_deactivate_after_rcu(struct kmem_cache
*s
)
764 __kmemcg_cache_deactivate_after_rcu(s
);
765 percpu_ref_kill(&s
->memcg_params
.refcnt
);
768 static void kmemcg_cache_deactivate(struct kmem_cache
*s
)
770 if (WARN_ON_ONCE(is_root_cache(s
)))
773 __kmemcg_cache_deactivate(s
);
774 s
->flags
|= SLAB_DEACTIVATED
;
777 * memcg_kmem_wq_lock is used to synchronize memcg_params.dying
778 * flag and make sure that no new kmem_cache deactivation tasks
779 * are queued (see flush_memcg_workqueue() ).
781 spin_lock_irq(&memcg_kmem_wq_lock
);
782 if (s
->memcg_params
.root_cache
->memcg_params
.dying
)
785 s
->memcg_params
.work_fn
= kmemcg_cache_deactivate_after_rcu
;
786 call_rcu(&s
->memcg_params
.rcu_head
, kmemcg_rcufn
);
788 spin_unlock_irq(&memcg_kmem_wq_lock
);
791 void memcg_deactivate_kmem_caches(struct mem_cgroup
*memcg
,
792 struct mem_cgroup
*parent
)
795 struct memcg_cache_array
*arr
;
796 struct kmem_cache
*s
, *c
;
797 unsigned int nr_reparented
;
799 idx
= memcg_cache_id(memcg
);
804 mutex_lock(&slab_mutex
);
805 list_for_each_entry(s
, &slab_root_caches
, root_caches_node
) {
806 arr
= rcu_dereference_protected(s
->memcg_params
.memcg_caches
,
807 lockdep_is_held(&slab_mutex
));
808 c
= arr
->entries
[idx
];
812 kmemcg_cache_deactivate(c
);
813 arr
->entries
[idx
] = NULL
;
816 list_for_each_entry(s
, &memcg
->kmem_caches
,
817 memcg_params
.kmem_caches_node
) {
818 WRITE_ONCE(s
->memcg_params
.memcg
, parent
);
819 css_put(&memcg
->css
);
823 list_splice_init(&memcg
->kmem_caches
,
824 &parent
->kmem_caches
);
825 css_get_many(&parent
->css
, nr_reparented
);
827 mutex_unlock(&slab_mutex
);
833 static int shutdown_memcg_caches(struct kmem_cache
*s
)
835 struct memcg_cache_array
*arr
;
836 struct kmem_cache
*c
, *c2
;
840 BUG_ON(!is_root_cache(s
));
843 * First, shutdown active caches, i.e. caches that belong to online
846 arr
= rcu_dereference_protected(s
->memcg_params
.memcg_caches
,
847 lockdep_is_held(&slab_mutex
));
848 for_each_memcg_cache_index(i
) {
852 if (shutdown_cache(c
))
854 * The cache still has objects. Move it to a temporary
855 * list so as not to try to destroy it for a second
856 * time while iterating over inactive caches below.
858 list_move(&c
->memcg_params
.children_node
, &busy
);
861 * The cache is empty and will be destroyed soon. Clear
862 * the pointer to it in the memcg_caches array so that
863 * it will never be accessed even if the root cache
866 arr
->entries
[i
] = NULL
;
870 * Second, shutdown all caches left from memory cgroups that are now
873 list_for_each_entry_safe(c
, c2
, &s
->memcg_params
.children
,
874 memcg_params
.children_node
)
877 list_splice(&busy
, &s
->memcg_params
.children
);
880 * A cache being destroyed must be empty. In particular, this means
881 * that all per memcg caches attached to it must be empty too.
883 if (!list_empty(&s
->memcg_params
.children
))
888 static void memcg_set_kmem_cache_dying(struct kmem_cache
*s
)
890 spin_lock_irq(&memcg_kmem_wq_lock
);
891 s
->memcg_params
.dying
= true;
892 spin_unlock_irq(&memcg_kmem_wq_lock
);
895 static void flush_memcg_workqueue(struct kmem_cache
*s
)
898 * SLAB and SLUB deactivate the kmem_caches through call_rcu. Make
899 * sure all registered rcu callbacks have been invoked.
904 * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB
905 * deactivates the memcg kmem_caches through workqueue. Make sure all
906 * previous workitems on workqueue are processed.
908 if (likely(memcg_kmem_cache_wq
))
909 flush_workqueue(memcg_kmem_cache_wq
);
912 * If we're racing with children kmem_cache deactivation, it might
913 * take another rcu grace period to complete their destruction.
914 * At this moment the corresponding percpu_ref_kill() call should be
915 * done, but it might take another rcu grace period to complete
916 * switching to the atomic mode.
917 * Please, note that we check without grabbing the slab_mutex. It's safe
918 * because at this moment the children list can't grow.
920 if (!list_empty(&s
->memcg_params
.children
))
924 static inline int shutdown_memcg_caches(struct kmem_cache
*s
)
928 #endif /* CONFIG_MEMCG_KMEM */
930 void slab_kmem_cache_release(struct kmem_cache
*s
)
932 __kmem_cache_release(s
);
933 destroy_memcg_params(s
);
934 kfree_const(s
->name
);
935 kmem_cache_free(kmem_cache
, s
);
938 void kmem_cache_destroy(struct kmem_cache
*s
)
948 mutex_lock(&slab_mutex
);
954 #ifdef CONFIG_MEMCG_KMEM
955 memcg_set_kmem_cache_dying(s
);
957 mutex_unlock(&slab_mutex
);
962 flush_memcg_workqueue(s
);
967 mutex_lock(&slab_mutex
);
970 * Another thread referenced it again
972 if (READ_ONCE(s
->refcount
)) {
973 spin_lock_irq(&memcg_kmem_wq_lock
);
974 s
->memcg_params
.dying
= false;
975 spin_unlock_irq(&memcg_kmem_wq_lock
);
980 err
= shutdown_memcg_caches(s
);
982 err
= shutdown_cache(s
);
985 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
990 mutex_unlock(&slab_mutex
);
995 EXPORT_SYMBOL(kmem_cache_destroy
);
998 * kmem_cache_shrink - Shrink a cache.
999 * @cachep: The cache to shrink.
1001 * Releases as many slabs as possible for a cache.
1002 * To help debugging, a zero exit status indicates all slabs were released.
1004 * Return: %0 if all slabs were released, non-zero otherwise
1006 int kmem_cache_shrink(struct kmem_cache
*cachep
)
1012 kasan_cache_shrink(cachep
);
1013 ret
= __kmem_cache_shrink(cachep
);
1018 EXPORT_SYMBOL(kmem_cache_shrink
);
1021 * kmem_cache_shrink_all - shrink a cache and all memcg caches for root cache
1022 * @s: The cache pointer
1024 void kmem_cache_shrink_all(struct kmem_cache
*s
)
1026 struct kmem_cache
*c
;
1028 if (!IS_ENABLED(CONFIG_MEMCG_KMEM
) || !is_root_cache(s
)) {
1029 kmem_cache_shrink(s
);
1035 kasan_cache_shrink(s
);
1036 __kmem_cache_shrink(s
);
1039 * We have to take the slab_mutex to protect from the memcg list
1042 mutex_lock(&slab_mutex
);
1043 for_each_memcg_cache(c
, s
) {
1045 * Don't need to shrink deactivated memcg caches.
1047 if (s
->flags
& SLAB_DEACTIVATED
)
1049 kasan_cache_shrink(c
);
1050 __kmem_cache_shrink(c
);
1052 mutex_unlock(&slab_mutex
);
1057 bool slab_is_available(void)
1059 return slab_state
>= UP
;
1063 /* Create a cache during boot when no slab services are available yet */
1064 void __init
create_boot_cache(struct kmem_cache
*s
, const char *name
,
1065 unsigned int size
, slab_flags_t flags
,
1066 unsigned int useroffset
, unsigned int usersize
)
1069 unsigned int align
= ARCH_KMALLOC_MINALIGN
;
1072 s
->size
= s
->object_size
= size
;
1075 * For power of two sizes, guarantee natural alignment for kmalloc
1076 * caches, regardless of SL*B debugging options.
1078 if (is_power_of_2(size
))
1079 align
= max(align
, size
);
1080 s
->align
= calculate_alignment(flags
, align
, size
);
1082 s
->useroffset
= useroffset
;
1083 s
->usersize
= usersize
;
1085 slab_init_memcg_params(s
);
1087 err
= __kmem_cache_create(s
, flags
);
1090 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
1093 s
->refcount
= -1; /* Exempt from merging for now */
1096 struct kmem_cache
*__init
create_kmalloc_cache(const char *name
,
1097 unsigned int size
, slab_flags_t flags
,
1098 unsigned int useroffset
, unsigned int usersize
)
1100 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
1103 panic("Out of memory when creating slab %s\n", name
);
1105 create_boot_cache(s
, name
, size
, flags
, useroffset
, usersize
);
1106 list_add(&s
->list
, &slab_caches
);
1107 memcg_link_cache(s
, NULL
);
1113 kmalloc_caches
[NR_KMALLOC_TYPES
][KMALLOC_SHIFT_HIGH
+ 1] __ro_after_init
=
1114 { /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
1115 EXPORT_SYMBOL(kmalloc_caches
);
1118 * Conversion table for small slabs sizes / 8 to the index in the
1119 * kmalloc array. This is necessary for slabs < 192 since we have non power
1120 * of two cache sizes there. The size of larger slabs can be determined using
1123 static u8 size_index
[24] __ro_after_init
= {
1150 static inline unsigned int size_index_elem(unsigned int bytes
)
1152 return (bytes
- 1) / 8;
1156 * Find the kmem_cache structure that serves a given size of
1159 struct kmem_cache
*kmalloc_slab(size_t size
, gfp_t flags
)
1165 return ZERO_SIZE_PTR
;
1167 index
= size_index
[size_index_elem(size
)];
1169 if (WARN_ON_ONCE(size
> KMALLOC_MAX_CACHE_SIZE
))
1171 index
= fls(size
- 1);
1174 return kmalloc_caches
[kmalloc_type(flags
)][index
];
1178 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
1179 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
1182 const struct kmalloc_info_struct kmalloc_info
[] __initconst
= {
1183 {NULL
, 0}, {"kmalloc-96", 96},
1184 {"kmalloc-192", 192}, {"kmalloc-8", 8},
1185 {"kmalloc-16", 16}, {"kmalloc-32", 32},
1186 {"kmalloc-64", 64}, {"kmalloc-128", 128},
1187 {"kmalloc-256", 256}, {"kmalloc-512", 512},
1188 {"kmalloc-1k", 1024}, {"kmalloc-2k", 2048},
1189 {"kmalloc-4k", 4096}, {"kmalloc-8k", 8192},
1190 {"kmalloc-16k", 16384}, {"kmalloc-32k", 32768},
1191 {"kmalloc-64k", 65536}, {"kmalloc-128k", 131072},
1192 {"kmalloc-256k", 262144}, {"kmalloc-512k", 524288},
1193 {"kmalloc-1M", 1048576}, {"kmalloc-2M", 2097152},
1194 {"kmalloc-4M", 4194304}, {"kmalloc-8M", 8388608},
1195 {"kmalloc-16M", 16777216}, {"kmalloc-32M", 33554432},
1196 {"kmalloc-64M", 67108864}
1200 * Patch up the size_index table if we have strange large alignment
1201 * requirements for the kmalloc array. This is only the case for
1202 * MIPS it seems. The standard arches will not generate any code here.
1204 * Largest permitted alignment is 256 bytes due to the way we
1205 * handle the index determination for the smaller caches.
1207 * Make sure that nothing crazy happens if someone starts tinkering
1208 * around with ARCH_KMALLOC_MINALIGN
1210 void __init
setup_kmalloc_cache_index_table(void)
1214 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 256 ||
1215 (KMALLOC_MIN_SIZE
& (KMALLOC_MIN_SIZE
- 1)));
1217 for (i
= 8; i
< KMALLOC_MIN_SIZE
; i
+= 8) {
1218 unsigned int elem
= size_index_elem(i
);
1220 if (elem
>= ARRAY_SIZE(size_index
))
1222 size_index
[elem
] = KMALLOC_SHIFT_LOW
;
1225 if (KMALLOC_MIN_SIZE
>= 64) {
1227 * The 96 byte size cache is not used if the alignment
1230 for (i
= 64 + 8; i
<= 96; i
+= 8)
1231 size_index
[size_index_elem(i
)] = 7;
1235 if (KMALLOC_MIN_SIZE
>= 128) {
1237 * The 192 byte sized cache is not used if the alignment
1238 * is 128 byte. Redirect kmalloc to use the 256 byte cache
1241 for (i
= 128 + 8; i
<= 192; i
+= 8)
1242 size_index
[size_index_elem(i
)] = 8;
1247 kmalloc_cache_name(const char *prefix
, unsigned int size
)
1250 static const char units
[3] = "\0kM";
1253 while (size
>= 1024 && (size
% 1024 == 0)) {
1258 return kasprintf(GFP_NOWAIT
, "%s-%u%c", prefix
, size
, units
[idx
]);
1262 new_kmalloc_cache(int idx
, int type
, slab_flags_t flags
)
1266 if (type
== KMALLOC_RECLAIM
) {
1267 flags
|= SLAB_RECLAIM_ACCOUNT
;
1268 name
= kmalloc_cache_name("kmalloc-rcl",
1269 kmalloc_info
[idx
].size
);
1272 name
= kmalloc_info
[idx
].name
;
1275 kmalloc_caches
[type
][idx
] = create_kmalloc_cache(name
,
1276 kmalloc_info
[idx
].size
, flags
, 0,
1277 kmalloc_info
[idx
].size
);
1281 * Create the kmalloc array. Some of the regular kmalloc arrays
1282 * may already have been created because they were needed to
1283 * enable allocations for slab creation.
1285 void __init
create_kmalloc_caches(slab_flags_t flags
)
1289 for (type
= KMALLOC_NORMAL
; type
<= KMALLOC_RECLAIM
; type
++) {
1290 for (i
= KMALLOC_SHIFT_LOW
; i
<= KMALLOC_SHIFT_HIGH
; i
++) {
1291 if (!kmalloc_caches
[type
][i
])
1292 new_kmalloc_cache(i
, type
, flags
);
1295 * Caches that are not of the two-to-the-power-of size.
1296 * These have to be created immediately after the
1297 * earlier power of two caches
1299 if (KMALLOC_MIN_SIZE
<= 32 && i
== 6 &&
1300 !kmalloc_caches
[type
][1])
1301 new_kmalloc_cache(1, type
, flags
);
1302 if (KMALLOC_MIN_SIZE
<= 64 && i
== 7 &&
1303 !kmalloc_caches
[type
][2])
1304 new_kmalloc_cache(2, type
, flags
);
1308 /* Kmalloc array is now usable */
1311 #ifdef CONFIG_ZONE_DMA
1312 for (i
= 0; i
<= KMALLOC_SHIFT_HIGH
; i
++) {
1313 struct kmem_cache
*s
= kmalloc_caches
[KMALLOC_NORMAL
][i
];
1316 unsigned int size
= kmalloc_size(i
);
1317 const char *n
= kmalloc_cache_name("dma-kmalloc", size
);
1320 kmalloc_caches
[KMALLOC_DMA
][i
] = create_kmalloc_cache(
1321 n
, size
, SLAB_CACHE_DMA
| flags
, 0, kmalloc_info
[i
].size
);
1326 #endif /* !CONFIG_SLOB */
1329 * To avoid unnecessary overhead, we pass through large allocation requests
1330 * directly to the page allocator. We use __GFP_COMP, because we will need to
1331 * know the allocation order to free the pages properly in kfree.
1333 void *kmalloc_order(size_t size
, gfp_t flags
, unsigned int order
)
1338 flags
|= __GFP_COMP
;
1339 page
= alloc_pages(flags
, order
);
1341 ret
= page_address(page
);
1342 mod_node_page_state(page_pgdat(page
), NR_SLAB_UNRECLAIMABLE
,
1345 ret
= kasan_kmalloc_large(ret
, size
, flags
);
1346 /* As ret might get tagged, call kmemleak hook after KASAN. */
1347 kmemleak_alloc(ret
, size
, 1, flags
);
1350 EXPORT_SYMBOL(kmalloc_order
);
1352 #ifdef CONFIG_TRACING
1353 void *kmalloc_order_trace(size_t size
, gfp_t flags
, unsigned int order
)
1355 void *ret
= kmalloc_order(size
, flags
, order
);
1356 trace_kmalloc(_RET_IP_
, ret
, size
, PAGE_SIZE
<< order
, flags
);
1359 EXPORT_SYMBOL(kmalloc_order_trace
);
1362 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1363 /* Randomize a generic freelist */
1364 static void freelist_randomize(struct rnd_state
*state
, unsigned int *list
,
1370 for (i
= 0; i
< count
; i
++)
1373 /* Fisher-Yates shuffle */
1374 for (i
= count
- 1; i
> 0; i
--) {
1375 rand
= prandom_u32_state(state
);
1377 swap(list
[i
], list
[rand
]);
1381 /* Create a random sequence per cache */
1382 int cache_random_seq_create(struct kmem_cache
*cachep
, unsigned int count
,
1385 struct rnd_state state
;
1387 if (count
< 2 || cachep
->random_seq
)
1390 cachep
->random_seq
= kcalloc(count
, sizeof(unsigned int), gfp
);
1391 if (!cachep
->random_seq
)
1394 /* Get best entropy at this stage of boot */
1395 prandom_seed_state(&state
, get_random_long());
1397 freelist_randomize(&state
, cachep
->random_seq
, count
);
1401 /* Destroy the per-cache random freelist sequence */
1402 void cache_random_seq_destroy(struct kmem_cache
*cachep
)
1404 kfree(cachep
->random_seq
);
1405 cachep
->random_seq
= NULL
;
1407 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1409 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
1411 #define SLABINFO_RIGHTS (0600)
1413 #define SLABINFO_RIGHTS (0400)
1416 static void print_slabinfo_header(struct seq_file
*m
)
1419 * Output format version, so at least we can change it
1420 * without _too_ many complaints.
1422 #ifdef CONFIG_DEBUG_SLAB
1423 seq_puts(m
, "slabinfo - version: 2.1 (statistics)\n");
1425 seq_puts(m
, "slabinfo - version: 2.1\n");
1427 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
1428 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
1429 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
1430 #ifdef CONFIG_DEBUG_SLAB
1431 seq_puts(m
, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
1432 seq_puts(m
, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
1437 void *slab_start(struct seq_file
*m
, loff_t
*pos
)
1439 mutex_lock(&slab_mutex
);
1440 return seq_list_start(&slab_root_caches
, *pos
);
1443 void *slab_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
1445 return seq_list_next(p
, &slab_root_caches
, pos
);
1448 void slab_stop(struct seq_file
*m
, void *p
)
1450 mutex_unlock(&slab_mutex
);
1454 memcg_accumulate_slabinfo(struct kmem_cache
*s
, struct slabinfo
*info
)
1456 struct kmem_cache
*c
;
1457 struct slabinfo sinfo
;
1459 if (!is_root_cache(s
))
1462 for_each_memcg_cache(c
, s
) {
1463 memset(&sinfo
, 0, sizeof(sinfo
));
1464 get_slabinfo(c
, &sinfo
);
1466 info
->active_slabs
+= sinfo
.active_slabs
;
1467 info
->num_slabs
+= sinfo
.num_slabs
;
1468 info
->shared_avail
+= sinfo
.shared_avail
;
1469 info
->active_objs
+= sinfo
.active_objs
;
1470 info
->num_objs
+= sinfo
.num_objs
;
1474 static void cache_show(struct kmem_cache
*s
, struct seq_file
*m
)
1476 struct slabinfo sinfo
;
1478 memset(&sinfo
, 0, sizeof(sinfo
));
1479 get_slabinfo(s
, &sinfo
);
1481 memcg_accumulate_slabinfo(s
, &sinfo
);
1483 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d",
1484 cache_name(s
), sinfo
.active_objs
, sinfo
.num_objs
, s
->size
,
1485 sinfo
.objects_per_slab
, (1 << sinfo
.cache_order
));
1487 seq_printf(m
, " : tunables %4u %4u %4u",
1488 sinfo
.limit
, sinfo
.batchcount
, sinfo
.shared
);
1489 seq_printf(m
, " : slabdata %6lu %6lu %6lu",
1490 sinfo
.active_slabs
, sinfo
.num_slabs
, sinfo
.shared_avail
);
1491 slabinfo_show_stats(m
, s
);
1495 static int slab_show(struct seq_file
*m
, void *p
)
1497 struct kmem_cache
*s
= list_entry(p
, struct kmem_cache
, root_caches_node
);
1499 if (p
== slab_root_caches
.next
)
1500 print_slabinfo_header(m
);
1505 void dump_unreclaimable_slab(void)
1507 struct kmem_cache
*s
, *s2
;
1508 struct slabinfo sinfo
;
1511 * Here acquiring slab_mutex is risky since we don't prefer to get
1512 * sleep in oom path. But, without mutex hold, it may introduce a
1514 * Use mutex_trylock to protect the list traverse, dump nothing
1515 * without acquiring the mutex.
1517 if (!mutex_trylock(&slab_mutex
)) {
1518 pr_warn("excessive unreclaimable slab but cannot dump stats\n");
1522 pr_info("Unreclaimable slab info:\n");
1523 pr_info("Name Used Total\n");
1525 list_for_each_entry_safe(s
, s2
, &slab_caches
, list
) {
1526 if (!is_root_cache(s
) || (s
->flags
& SLAB_RECLAIM_ACCOUNT
))
1529 get_slabinfo(s
, &sinfo
);
1531 if (sinfo
.num_objs
> 0)
1532 pr_info("%-17s %10luKB %10luKB\n", cache_name(s
),
1533 (sinfo
.active_objs
* s
->size
) / 1024,
1534 (sinfo
.num_objs
* s
->size
) / 1024);
1536 mutex_unlock(&slab_mutex
);
1539 #if defined(CONFIG_MEMCG)
1540 void *memcg_slab_start(struct seq_file
*m
, loff_t
*pos
)
1542 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
1544 mutex_lock(&slab_mutex
);
1545 return seq_list_start(&memcg
->kmem_caches
, *pos
);
1548 void *memcg_slab_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
1550 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
1552 return seq_list_next(p
, &memcg
->kmem_caches
, pos
);
1555 void memcg_slab_stop(struct seq_file
*m
, void *p
)
1557 mutex_unlock(&slab_mutex
);
1560 int memcg_slab_show(struct seq_file
*m
, void *p
)
1562 struct kmem_cache
*s
= list_entry(p
, struct kmem_cache
,
1563 memcg_params
.kmem_caches_node
);
1564 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
1566 if (p
== memcg
->kmem_caches
.next
)
1567 print_slabinfo_header(m
);
1574 * slabinfo_op - iterator that generates /proc/slabinfo
1583 * num-pages-per-slab
1584 * + further values on SMP and with statistics enabled
1586 static const struct seq_operations slabinfo_op
= {
1587 .start
= slab_start
,
1593 static int slabinfo_open(struct inode
*inode
, struct file
*file
)
1595 return seq_open(file
, &slabinfo_op
);
1598 static const struct file_operations proc_slabinfo_operations
= {
1599 .open
= slabinfo_open
,
1601 .write
= slabinfo_write
,
1602 .llseek
= seq_lseek
,
1603 .release
= seq_release
,
1606 static int __init
slab_proc_init(void)
1608 proc_create("slabinfo", SLABINFO_RIGHTS
, NULL
,
1609 &proc_slabinfo_operations
);
1612 module_init(slab_proc_init
);
1614 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_MEMCG_KMEM)
1616 * Display information about kmem caches that have child memcg caches.
1618 static int memcg_slabinfo_show(struct seq_file
*m
, void *unused
)
1620 struct kmem_cache
*s
, *c
;
1621 struct slabinfo sinfo
;
1623 mutex_lock(&slab_mutex
);
1624 seq_puts(m
, "# <name> <css_id[:dead|deact]> <active_objs> <num_objs>");
1625 seq_puts(m
, " <active_slabs> <num_slabs>\n");
1626 list_for_each_entry(s
, &slab_root_caches
, root_caches_node
) {
1628 * Skip kmem caches that don't have any memcg children.
1630 if (list_empty(&s
->memcg_params
.children
))
1633 memset(&sinfo
, 0, sizeof(sinfo
));
1634 get_slabinfo(s
, &sinfo
);
1635 seq_printf(m
, "%-17s root %6lu %6lu %6lu %6lu\n",
1636 cache_name(s
), sinfo
.active_objs
, sinfo
.num_objs
,
1637 sinfo
.active_slabs
, sinfo
.num_slabs
);
1639 for_each_memcg_cache(c
, s
) {
1640 struct cgroup_subsys_state
*css
;
1643 css
= &c
->memcg_params
.memcg
->css
;
1644 if (!(css
->flags
& CSS_ONLINE
))
1646 else if (c
->flags
& SLAB_DEACTIVATED
)
1649 memset(&sinfo
, 0, sizeof(sinfo
));
1650 get_slabinfo(c
, &sinfo
);
1651 seq_printf(m
, "%-17s %4d%-6s %6lu %6lu %6lu %6lu\n",
1652 cache_name(c
), css
->id
, status
,
1653 sinfo
.active_objs
, sinfo
.num_objs
,
1654 sinfo
.active_slabs
, sinfo
.num_slabs
);
1657 mutex_unlock(&slab_mutex
);
1660 DEFINE_SHOW_ATTRIBUTE(memcg_slabinfo
);
1662 static int __init
memcg_slabinfo_init(void)
1664 debugfs_create_file("memcg_slabinfo", S_IFREG
| S_IRUGO
,
1665 NULL
, NULL
, &memcg_slabinfo_fops
);
1669 late_initcall(memcg_slabinfo_init
);
1670 #endif /* CONFIG_DEBUG_FS && CONFIG_MEMCG_KMEM */
1671 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
1673 static __always_inline
void *__do_krealloc(const void *p
, size_t new_size
,
1682 if (ks
>= new_size
) {
1683 p
= kasan_krealloc((void *)p
, new_size
, flags
);
1687 ret
= kmalloc_track_caller(new_size
, flags
);
1695 * __krealloc - like krealloc() but don't free @p.
1696 * @p: object to reallocate memory for.
1697 * @new_size: how many bytes of memory are required.
1698 * @flags: the type of memory to allocate.
1700 * This function is like krealloc() except it never frees the originally
1701 * allocated buffer. Use this if you don't want to free the buffer immediately
1702 * like, for example, with RCU.
1704 * Return: pointer to the allocated memory or %NULL in case of error
1706 void *__krealloc(const void *p
, size_t new_size
, gfp_t flags
)
1708 if (unlikely(!new_size
))
1709 return ZERO_SIZE_PTR
;
1711 return __do_krealloc(p
, new_size
, flags
);
1714 EXPORT_SYMBOL(__krealloc
);
1717 * krealloc - reallocate memory. The contents will remain unchanged.
1718 * @p: object to reallocate memory for.
1719 * @new_size: how many bytes of memory are required.
1720 * @flags: the type of memory to allocate.
1722 * The contents of the object pointed to are preserved up to the
1723 * lesser of the new and old sizes. If @p is %NULL, krealloc()
1724 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
1725 * %NULL pointer, the object pointed to is freed.
1727 * Return: pointer to the allocated memory or %NULL in case of error
1729 void *krealloc(const void *p
, size_t new_size
, gfp_t flags
)
1733 if (unlikely(!new_size
)) {
1735 return ZERO_SIZE_PTR
;
1738 ret
= __do_krealloc(p
, new_size
, flags
);
1739 if (ret
&& kasan_reset_tag(p
) != kasan_reset_tag(ret
))
1744 EXPORT_SYMBOL(krealloc
);
1747 * kzfree - like kfree but zero memory
1748 * @p: object to free memory of
1750 * The memory of the object @p points to is zeroed before freed.
1751 * If @p is %NULL, kzfree() does nothing.
1753 * Note: this function zeroes the whole allocated buffer which can be a good
1754 * deal bigger than the requested buffer size passed to kmalloc(). So be
1755 * careful when using this function in performance sensitive code.
1757 void kzfree(const void *p
)
1760 void *mem
= (void *)p
;
1762 if (unlikely(ZERO_OR_NULL_PTR(mem
)))
1765 memzero_explicit(mem
, ks
);
1768 EXPORT_SYMBOL(kzfree
);
1771 * ksize - get the actual amount of memory allocated for a given object
1772 * @objp: Pointer to the object
1774 * kmalloc may internally round up allocations and return more memory
1775 * than requested. ksize() can be used to determine the actual amount of
1776 * memory allocated. The caller may use this additional memory, even though
1777 * a smaller amount of memory was initially specified with the kmalloc call.
1778 * The caller must guarantee that objp points to a valid object previously
1779 * allocated with either kmalloc() or kmem_cache_alloc(). The object
1780 * must not be freed during the duration of the call.
1782 * Return: size of the actual memory used by @objp in bytes
1784 size_t ksize(const void *objp
)
1788 if (WARN_ON_ONCE(!objp
))
1791 * We need to check that the pointed to object is valid, and only then
1792 * unpoison the shadow memory below. We use __kasan_check_read(), to
1793 * generate a more useful report at the time ksize() is called (rather
1794 * than later where behaviour is undefined due to potential
1795 * use-after-free or double-free).
1797 * If the pointed to memory is invalid we return 0, to avoid users of
1798 * ksize() writing to and potentially corrupting the memory region.
1800 * We want to perform the check before __ksize(), to avoid potentially
1801 * crashing in __ksize() due to accessing invalid metadata.
1803 if (unlikely(objp
== ZERO_SIZE_PTR
) || !__kasan_check_read(objp
, 1))
1806 size
= __ksize(objp
);
1808 * We assume that ksize callers could use whole allocated area,
1809 * so we need to unpoison this area.
1811 kasan_unpoison_shadow(objp
, size
);
1814 EXPORT_SYMBOL(ksize
);
1816 /* Tracepoints definitions. */
1817 EXPORT_TRACEPOINT_SYMBOL(kmalloc
);
1818 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc
);
1819 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node
);
1820 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node
);
1821 EXPORT_TRACEPOINT_SYMBOL(kfree
);
1822 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free
);
1824 int should_failslab(struct kmem_cache
*s
, gfp_t gfpflags
)
1826 if (__should_failslab(s
, gfpflags
))
1830 ALLOW_ERROR_INJECTION(should_failslab
, ERRNO
);