1 // SPDX-License-Identifier: GPL-2.0
3 * SLUB: A slab allocator that limits cache line use instead of queuing
4 * objects in per cpu and per node lists.
6 * The allocator synchronizes using per slab locks or atomic operations
7 * and only uses a centralized lock to manage a pool of partial slabs.
9 * (C) 2007 SGI, Christoph Lameter
10 * (C) 2011 Linux Foundation, Christoph Lameter
14 #include <linux/swap.h> /* mm_account_reclaimed_pages() */
15 #include <linux/module.h>
16 #include <linux/bit_spinlock.h>
17 #include <linux/interrupt.h>
18 #include <linux/swab.h>
19 #include <linux/bitops.h>
20 #include <linux/slab.h>
22 #include <linux/proc_fs.h>
23 #include <linux/seq_file.h>
24 #include <linux/kasan.h>
25 #include <linux/kmsan.h>
26 #include <linux/cpu.h>
27 #include <linux/cpuset.h>
28 #include <linux/mempolicy.h>
29 #include <linux/ctype.h>
30 #include <linux/stackdepot.h>
31 #include <linux/debugobjects.h>
32 #include <linux/kallsyms.h>
33 #include <linux/kfence.h>
34 #include <linux/memory.h>
35 #include <linux/math64.h>
36 #include <linux/fault-inject.h>
37 #include <linux/kmemleak.h>
38 #include <linux/stacktrace.h>
39 #include <linux/prefetch.h>
40 #include <linux/memcontrol.h>
41 #include <linux/random.h>
42 #include <kunit/test.h>
43 #include <kunit/test-bug.h>
44 #include <linux/sort.h>
46 #include <linux/debugfs.h>
47 #include <trace/events/kmem.h>
53 * 1. slab_mutex (Global Mutex)
54 * 2. node->list_lock (Spinlock)
55 * 3. kmem_cache->cpu_slab->lock (Local lock)
56 * 4. slab_lock(slab) (Only on some arches)
57 * 5. object_map_lock (Only for debugging)
61 * The role of the slab_mutex is to protect the list of all the slabs
62 * and to synchronize major metadata changes to slab cache structures.
63 * Also synchronizes memory hotplug callbacks.
67 * The slab_lock is a wrapper around the page lock, thus it is a bit
70 * The slab_lock is only used on arches that do not have the ability
71 * to do a cmpxchg_double. It only protects:
73 * A. slab->freelist -> List of free objects in a slab
74 * B. slab->inuse -> Number of objects in use
75 * C. slab->objects -> Number of objects in slab
76 * D. slab->frozen -> frozen state
80 * If a slab is frozen then it is exempt from list management. It is
81 * the cpu slab which is actively allocated from by the processor that
82 * froze it and it is not on any list. The processor that froze the
83 * slab is the one who can perform list operations on the slab. Other
84 * processors may put objects onto the freelist but the processor that
85 * froze the slab is the only one that can retrieve the objects from the
90 * The partially empty slabs cached on the CPU partial list are used
91 * for performance reasons, which speeds up the allocation process.
92 * These slabs are not frozen, but are also exempt from list management,
93 * by clearing the PG_workingset flag when moving out of the node
94 * partial list. Please see __slab_free() for more details.
96 * To sum up, the current scheme is:
97 * - node partial slab: PG_Workingset && !frozen
98 * - cpu partial slab: !PG_Workingset && !frozen
99 * - cpu slab: !PG_Workingset && frozen
100 * - full slab: !PG_Workingset && !frozen
104 * The list_lock protects the partial and full list on each node and
105 * the partial slab counter. If taken then no new slabs may be added or
106 * removed from the lists nor make the number of partial slabs be modified.
107 * (Note that the total number of slabs is an atomic value that may be
108 * modified without taking the list lock).
110 * The list_lock is a centralized lock and thus we avoid taking it as
111 * much as possible. As long as SLUB does not have to handle partial
112 * slabs, operations can continue without any centralized lock. F.e.
113 * allocating a long series of objects that fill up slabs does not require
116 * For debug caches, all allocations are forced to go through a list_lock
117 * protected region to serialize against concurrent validation.
119 * cpu_slab->lock local lock
121 * This locks protect slowpath manipulation of all kmem_cache_cpu fields
122 * except the stat counters. This is a percpu structure manipulated only by
123 * the local cpu, so the lock protects against being preempted or interrupted
124 * by an irq. Fast path operations rely on lockless operations instead.
126 * On PREEMPT_RT, the local lock neither disables interrupts nor preemption
127 * which means the lockless fastpath cannot be used as it might interfere with
128 * an in-progress slow path operations. In this case the local lock is always
129 * taken but it still utilizes the freelist for the common operations.
133 * The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
134 * are fully lockless when satisfied from the percpu slab (and when
135 * cmpxchg_double is possible to use, otherwise slab_lock is taken).
136 * They also don't disable preemption or migration or irqs. They rely on
137 * the transaction id (tid) field to detect being preempted or moved to
140 * irq, preemption, migration considerations
142 * Interrupts are disabled as part of list_lock or local_lock operations, or
143 * around the slab_lock operation, in order to make the slab allocator safe
144 * to use in the context of an irq.
146 * In addition, preemption (or migration on PREEMPT_RT) is disabled in the
147 * allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
148 * local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
149 * doesn't have to be revalidated in each section protected by the local lock.
151 * SLUB assigns one slab for allocation to each processor.
152 * Allocations only occur from these slabs called cpu slabs.
154 * Slabs with free elements are kept on a partial list and during regular
155 * operations no list for full slabs is used. If an object in a full slab is
156 * freed then the slab will show up again on the partial lists.
157 * We track full slabs for debugging purposes though because otherwise we
158 * cannot scan all objects.
160 * Slabs are freed when they become empty. Teardown and setup is
161 * minimal so we rely on the page allocators per cpu caches for
162 * fast frees and allocs.
164 * slab->frozen The slab is frozen and exempt from list processing.
165 * This means that the slab is dedicated to a purpose
166 * such as satisfying allocations for a specific
167 * processor. Objects may be freed in the slab while
168 * it is frozen but slab_free will then skip the usual
169 * list operations. It is up to the processor holding
170 * the slab to integrate the slab into the slab lists
171 * when the slab is no longer needed.
173 * One use of this flag is to mark slabs that are
174 * used for allocations. Then such a slab becomes a cpu
175 * slab. The cpu slab may be equipped with an additional
176 * freelist that allows lockless access to
177 * free objects in addition to the regular freelist
178 * that requires the slab lock.
180 * SLAB_DEBUG_FLAGS Slab requires special handling due to debug
181 * options set. This moves slab handling out of
182 * the fast path and disables lockless freelists.
186 * We could simply use migrate_disable()/enable() but as long as it's a
187 * function call even on !PREEMPT_RT, use inline preempt_disable() there.
189 #ifndef CONFIG_PREEMPT_RT
190 #define slub_get_cpu_ptr(var) get_cpu_ptr(var)
191 #define slub_put_cpu_ptr(var) put_cpu_ptr(var)
192 #define USE_LOCKLESS_FAST_PATH() (true)
194 #define slub_get_cpu_ptr(var) \
199 #define slub_put_cpu_ptr(var) \
204 #define USE_LOCKLESS_FAST_PATH() (false)
207 #ifndef CONFIG_SLUB_TINY
208 #define __fastpath_inline __always_inline
210 #define __fastpath_inline
213 #ifdef CONFIG_SLUB_DEBUG
214 #ifdef CONFIG_SLUB_DEBUG_ON
215 DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
217 DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
219 #endif /* CONFIG_SLUB_DEBUG */
221 /* Structure holding parameters for get_partial() call chain */
222 struct partial_context {
224 unsigned int orig_size;
228 static inline bool kmem_cache_debug(struct kmem_cache *s)
230 return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
233 static inline bool slub_debug_orig_size(struct kmem_cache *s)
235 return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
236 (s->flags & SLAB_KMALLOC));
239 void *fixup_red_left(struct kmem_cache *s, void *p)
241 if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
242 p += s->red_left_pad;
247 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
249 #ifdef CONFIG_SLUB_CPU_PARTIAL
250 return !kmem_cache_debug(s);
257 * Issues still to be resolved:
259 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
261 * - Variable sizing of the per node arrays
264 /* Enable to log cmpxchg failures */
265 #undef SLUB_DEBUG_CMPXCHG
267 #ifndef CONFIG_SLUB_TINY
269 * Minimum number of partial slabs. These will be left on the partial
270 * lists even if they are empty. kmem_cache_shrink may reclaim them.
272 #define MIN_PARTIAL 5
275 * Maximum number of desirable partial slabs.
276 * The existence of more partial slabs makes kmem_cache_shrink
277 * sort the partial list by the number of objects in use.
279 #define MAX_PARTIAL 10
281 #define MIN_PARTIAL 0
282 #define MAX_PARTIAL 0
285 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
286 SLAB_POISON | SLAB_STORE_USER)
289 * These debug flags cannot use CMPXCHG because there might be consistency
290 * issues when checking or reading debug information
292 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
297 * Debugging flags that require metadata to be stored in the slab. These get
298 * disabled when slab_debug=O is used and a cache's min order increases with
301 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
304 #define OO_MASK ((1 << OO_SHIFT) - 1)
305 #define MAX_OBJS_PER_PAGE 32767 /* since slab.objects is u15 */
307 /* Internal SLUB flags */
309 #define __OBJECT_POISON __SLAB_FLAG_BIT(_SLAB_OBJECT_POISON)
310 /* Use cmpxchg_double */
312 #ifdef system_has_freelist_aba
313 #define __CMPXCHG_DOUBLE __SLAB_FLAG_BIT(_SLAB_CMPXCHG_DOUBLE)
315 #define __CMPXCHG_DOUBLE __SLAB_FLAG_UNUSED
319 * Tracking user of a slab.
321 #define TRACK_ADDRS_COUNT 16
323 unsigned long addr; /* Called from address */
324 #ifdef CONFIG_STACKDEPOT
325 depot_stack_handle_t handle;
327 int cpu; /* Was running on cpu */
328 int pid; /* Pid context */
329 unsigned long when; /* When did the operation occur */
332 enum track_item { TRACK_ALLOC, TRACK_FREE };
334 #ifdef SLAB_SUPPORTS_SYSFS
335 static int sysfs_slab_add(struct kmem_cache *);
336 static int sysfs_slab_alias(struct kmem_cache *, const char *);
338 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
339 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
343 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
344 static void debugfs_slab_add(struct kmem_cache *);
346 static inline void debugfs_slab_add(struct kmem_cache *s) { }
350 ALLOC_FASTPATH, /* Allocation from cpu slab */
351 ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */
352 FREE_FASTPATH, /* Free to cpu slab */
353 FREE_SLOWPATH, /* Freeing not to cpu slab */
354 FREE_FROZEN, /* Freeing to frozen slab */
355 FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
356 FREE_REMOVE_PARTIAL, /* Freeing removes last object */
357 ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */
358 ALLOC_SLAB, /* Cpu slab acquired from page allocator */
359 ALLOC_REFILL, /* Refill cpu slab from slab freelist */
360 ALLOC_NODE_MISMATCH, /* Switching cpu slab */
361 FREE_SLAB, /* Slab freed to the page allocator */
362 CPUSLAB_FLUSH, /* Abandoning of the cpu slab */
363 DEACTIVATE_FULL, /* Cpu slab was full when deactivated */
364 DEACTIVATE_EMPTY, /* Cpu slab was empty when deactivated */
365 DEACTIVATE_TO_HEAD, /* Cpu slab was moved to the head of partials */
366 DEACTIVATE_TO_TAIL, /* Cpu slab was moved to the tail of partials */
367 DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
368 DEACTIVATE_BYPASS, /* Implicit deactivation */
369 ORDER_FALLBACK, /* Number of times fallback was necessary */
370 CMPXCHG_DOUBLE_CPU_FAIL,/* Failures of this_cpu_cmpxchg_double */
371 CMPXCHG_DOUBLE_FAIL, /* Failures of slab freelist update */
372 CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
373 CPU_PARTIAL_FREE, /* Refill cpu partial on free */
374 CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */
375 CPU_PARTIAL_DRAIN, /* Drain cpu partial to node partial */
379 #ifndef CONFIG_SLUB_TINY
381 * When changing the layout, make sure freelist and tid are still compatible
382 * with this_cpu_cmpxchg_double() alignment requirements.
384 struct kmem_cache_cpu {
387 void **freelist; /* Pointer to next available object */
388 unsigned long tid; /* Globally unique transaction id */
390 freelist_aba_t freelist_tid;
392 struct slab *slab; /* The slab from which we are allocating */
393 #ifdef CONFIG_SLUB_CPU_PARTIAL
394 struct slab *partial; /* Partially allocated slabs */
396 local_lock_t lock; /* Protects the fields above */
397 #ifdef CONFIG_SLUB_STATS
398 unsigned int stat[NR_SLUB_STAT_ITEMS];
401 #endif /* CONFIG_SLUB_TINY */
403 static inline void stat(const struct kmem_cache *s, enum stat_item si)
405 #ifdef CONFIG_SLUB_STATS
407 * The rmw is racy on a preemptible kernel but this is acceptable, so
408 * avoid this_cpu_add()'s irq-disable overhead.
410 raw_cpu_inc(s->cpu_slab->stat[si]);
415 void stat_add(const struct kmem_cache *s, enum stat_item si, int v)
417 #ifdef CONFIG_SLUB_STATS
418 raw_cpu_add(s->cpu_slab->stat[si], v);
423 * The slab lists for all objects.
425 struct kmem_cache_node {
426 spinlock_t list_lock;
427 unsigned long nr_partial;
428 struct list_head partial;
429 #ifdef CONFIG_SLUB_DEBUG
430 atomic_long_t nr_slabs;
431 atomic_long_t total_objects;
432 struct list_head full;
436 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
438 return s->node[node];
442 * Iterator over all nodes. The body will be executed for each node that has
443 * a kmem_cache_node structure allocated (which is true for all online nodes)
445 #define for_each_kmem_cache_node(__s, __node, __n) \
446 for (__node = 0; __node < nr_node_ids; __node++) \
447 if ((__n = get_node(__s, __node)))
450 * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
451 * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
452 * differ during memory hotplug/hotremove operations.
453 * Protected by slab_mutex.
455 static nodemask_t slab_nodes;
457 #ifndef CONFIG_SLUB_TINY
459 * Workqueue used for flush_cpu_slab().
461 static struct workqueue_struct *flushwq;
464 /********************************************************************
465 * Core slab cache functions
466 *******************************************************************/
469 * freeptr_t represents a SLUB freelist pointer, which might be encoded
470 * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled.
472 typedef struct { unsigned long v; } freeptr_t;
475 * Returns freelist pointer (ptr). With hardening, this is obfuscated
476 * with an XOR of the address where the pointer is held and a per-cache
479 static inline freeptr_t freelist_ptr_encode(const struct kmem_cache *s,
480 void *ptr, unsigned long ptr_addr)
482 unsigned long encoded;
484 #ifdef CONFIG_SLAB_FREELIST_HARDENED
485 encoded = (unsigned long)ptr ^ s->random ^ swab(ptr_addr);
487 encoded = (unsigned long)ptr;
489 return (freeptr_t){.v = encoded};
492 static inline void *freelist_ptr_decode(const struct kmem_cache *s,
493 freeptr_t ptr, unsigned long ptr_addr)
497 #ifdef CONFIG_SLAB_FREELIST_HARDENED
498 decoded = (void *)(ptr.v ^ s->random ^ swab(ptr_addr));
500 decoded = (void *)ptr.v;
505 static inline void *get_freepointer(struct kmem_cache *s, void *object)
507 unsigned long ptr_addr;
510 object = kasan_reset_tag(object);
511 ptr_addr = (unsigned long)object + s->offset;
512 p = *(freeptr_t *)(ptr_addr);
513 return freelist_ptr_decode(s, p, ptr_addr);
516 #ifndef CONFIG_SLUB_TINY
517 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
519 prefetchw(object + s->offset);
524 * When running under KMSAN, get_freepointer_safe() may return an uninitialized
525 * pointer value in the case the current thread loses the race for the next
526 * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
527 * slab_alloc_node() will fail, so the uninitialized value won't be used, but
528 * KMSAN will still check all arguments of cmpxchg because of imperfect
529 * handling of inline assembly.
530 * To work around this problem, we apply __no_kmsan_checks to ensure that
531 * get_freepointer_safe() returns initialized memory.
534 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
536 unsigned long freepointer_addr;
539 if (!debug_pagealloc_enabled_static())
540 return get_freepointer(s, object);
542 object = kasan_reset_tag(object);
543 freepointer_addr = (unsigned long)object + s->offset;
544 copy_from_kernel_nofault(&p, (freeptr_t *)freepointer_addr, sizeof(p));
545 return freelist_ptr_decode(s, p, freepointer_addr);
548 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
550 unsigned long freeptr_addr = (unsigned long)object + s->offset;
552 #ifdef CONFIG_SLAB_FREELIST_HARDENED
553 BUG_ON(object == fp); /* naive detection of double free or corruption */
556 freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
557 *(freeptr_t *)freeptr_addr = freelist_ptr_encode(s, fp, freeptr_addr);
560 /* Loop over all objects in a slab */
561 #define for_each_object(__p, __s, __addr, __objects) \
562 for (__p = fixup_red_left(__s, __addr); \
563 __p < (__addr) + (__objects) * (__s)->size; \
566 static inline unsigned int order_objects(unsigned int order, unsigned int size)
568 return ((unsigned int)PAGE_SIZE << order) / size;
571 static inline struct kmem_cache_order_objects oo_make(unsigned int order,
574 struct kmem_cache_order_objects x = {
575 (order << OO_SHIFT) + order_objects(order, size)
581 static inline unsigned int oo_order(struct kmem_cache_order_objects x)
583 return x.x >> OO_SHIFT;
586 static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
588 return x.x & OO_MASK;
591 #ifdef CONFIG_SLUB_CPU_PARTIAL
592 static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
594 unsigned int nr_slabs;
596 s->cpu_partial = nr_objects;
599 * We take the number of objects but actually limit the number of
600 * slabs on the per cpu partial list, in order to limit excessive
601 * growth of the list. For simplicity we assume that the slabs will
604 nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
605 s->cpu_partial_slabs = nr_slabs;
609 slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
612 #endif /* CONFIG_SLUB_CPU_PARTIAL */
615 * Per slab locking using the pagelock
617 static __always_inline void slab_lock(struct slab *slab)
619 struct page *page = slab_page(slab);
621 VM_BUG_ON_PAGE(PageTail(page), page);
622 bit_spin_lock(PG_locked, &page->flags);
625 static __always_inline void slab_unlock(struct slab *slab)
627 struct page *page = slab_page(slab);
629 VM_BUG_ON_PAGE(PageTail(page), page);
630 bit_spin_unlock(PG_locked, &page->flags);
634 __update_freelist_fast(struct slab *slab,
635 void *freelist_old, unsigned long counters_old,
636 void *freelist_new, unsigned long counters_new)
638 #ifdef system_has_freelist_aba
639 freelist_aba_t old = { .freelist = freelist_old, .counter = counters_old };
640 freelist_aba_t new = { .freelist = freelist_new, .counter = counters_new };
642 return try_cmpxchg_freelist(&slab->freelist_counter.full, &old.full, new.full);
649 __update_freelist_slow(struct slab *slab,
650 void *freelist_old, unsigned long counters_old,
651 void *freelist_new, unsigned long counters_new)
656 if (slab->freelist == freelist_old &&
657 slab->counters == counters_old) {
658 slab->freelist = freelist_new;
659 slab->counters = counters_new;
668 * Interrupts must be disabled (for the fallback code to work right), typically
669 * by an _irqsave() lock variant. On PREEMPT_RT the preempt_disable(), which is
670 * part of bit_spin_lock(), is sufficient because the policy is not to allow any
671 * allocation/ free operation in hardirq context. Therefore nothing can
672 * interrupt the operation.
674 static inline bool __slab_update_freelist(struct kmem_cache *s, struct slab *slab,
675 void *freelist_old, unsigned long counters_old,
676 void *freelist_new, unsigned long counters_new,
681 if (USE_LOCKLESS_FAST_PATH())
682 lockdep_assert_irqs_disabled();
684 if (s->flags & __CMPXCHG_DOUBLE) {
685 ret = __update_freelist_fast(slab, freelist_old, counters_old,
686 freelist_new, counters_new);
688 ret = __update_freelist_slow(slab, freelist_old, counters_old,
689 freelist_new, counters_new);
695 stat(s, CMPXCHG_DOUBLE_FAIL);
697 #ifdef SLUB_DEBUG_CMPXCHG
698 pr_info("%s %s: cmpxchg double redo ", n, s->name);
704 static inline bool slab_update_freelist(struct kmem_cache *s, struct slab *slab,
705 void *freelist_old, unsigned long counters_old,
706 void *freelist_new, unsigned long counters_new,
711 if (s->flags & __CMPXCHG_DOUBLE) {
712 ret = __update_freelist_fast(slab, freelist_old, counters_old,
713 freelist_new, counters_new);
717 local_irq_save(flags);
718 ret = __update_freelist_slow(slab, freelist_old, counters_old,
719 freelist_new, counters_new);
720 local_irq_restore(flags);
726 stat(s, CMPXCHG_DOUBLE_FAIL);
728 #ifdef SLUB_DEBUG_CMPXCHG
729 pr_info("%s %s: cmpxchg double redo ", n, s->name);
735 #ifdef CONFIG_SLUB_DEBUG
736 static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
737 static DEFINE_SPINLOCK(object_map_lock);
739 static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
742 void *addr = slab_address(slab);
745 bitmap_zero(obj_map, slab->objects);
747 for (p = slab->freelist; p; p = get_freepointer(s, p))
748 set_bit(__obj_to_index(s, addr, p), obj_map);
751 #if IS_ENABLED(CONFIG_KUNIT)
752 static bool slab_add_kunit_errors(void)
754 struct kunit_resource *resource;
756 if (!kunit_get_current_test())
759 resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
763 (*(int *)resource->data)++;
764 kunit_put_resource(resource);
768 static inline bool slab_add_kunit_errors(void) { return false; }
771 static inline unsigned int size_from_object(struct kmem_cache *s)
773 if (s->flags & SLAB_RED_ZONE)
774 return s->size - s->red_left_pad;
779 static inline void *restore_red_left(struct kmem_cache *s, void *p)
781 if (s->flags & SLAB_RED_ZONE)
782 p -= s->red_left_pad;
790 #if defined(CONFIG_SLUB_DEBUG_ON)
791 static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
793 static slab_flags_t slub_debug;
796 static char *slub_debug_string;
797 static int disable_higher_order_debug;
800 * slub is about to manipulate internal object metadata. This memory lies
801 * outside the range of the allocated object, so accessing it would normally
802 * be reported by kasan as a bounds error. metadata_access_enable() is used
803 * to tell kasan that these accesses are OK.
805 static inline void metadata_access_enable(void)
807 kasan_disable_current();
810 static inline void metadata_access_disable(void)
812 kasan_enable_current();
819 /* Verify that a pointer has an address that is valid within a slab page */
820 static inline int check_valid_pointer(struct kmem_cache *s,
821 struct slab *slab, void *object)
828 base = slab_address(slab);
829 object = kasan_reset_tag(object);
830 object = restore_red_left(s, object);
831 if (object < base || object >= base + slab->objects * s->size ||
832 (object - base) % s->size) {
839 static void print_section(char *level, char *text, u8 *addr,
842 metadata_access_enable();
843 print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
844 16, 1, kasan_reset_tag((void *)addr), length, 1);
845 metadata_access_disable();
849 * See comment in calculate_sizes().
851 static inline bool freeptr_outside_object(struct kmem_cache *s)
853 return s->offset >= s->inuse;
857 * Return offset of the end of info block which is inuse + free pointer if
858 * not overlapping with object.
860 static inline unsigned int get_info_end(struct kmem_cache *s)
862 if (freeptr_outside_object(s))
863 return s->inuse + sizeof(void *);
868 static struct track *get_track(struct kmem_cache *s, void *object,
869 enum track_item alloc)
873 p = object + get_info_end(s);
875 return kasan_reset_tag(p + alloc);
878 #ifdef CONFIG_STACKDEPOT
879 static noinline depot_stack_handle_t set_track_prepare(void)
881 depot_stack_handle_t handle;
882 unsigned long entries[TRACK_ADDRS_COUNT];
883 unsigned int nr_entries;
885 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
886 handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
891 static inline depot_stack_handle_t set_track_prepare(void)
897 static void set_track_update(struct kmem_cache *s, void *object,
898 enum track_item alloc, unsigned long addr,
899 depot_stack_handle_t handle)
901 struct track *p = get_track(s, object, alloc);
903 #ifdef CONFIG_STACKDEPOT
907 p->cpu = smp_processor_id();
908 p->pid = current->pid;
912 static __always_inline void set_track(struct kmem_cache *s, void *object,
913 enum track_item alloc, unsigned long addr)
915 depot_stack_handle_t handle = set_track_prepare();
917 set_track_update(s, object, alloc, addr, handle);
920 static void init_tracking(struct kmem_cache *s, void *object)
924 if (!(s->flags & SLAB_STORE_USER))
927 p = get_track(s, object, TRACK_ALLOC);
928 memset(p, 0, 2*sizeof(struct track));
931 static void print_track(const char *s, struct track *t, unsigned long pr_time)
933 depot_stack_handle_t handle __maybe_unused;
938 pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
939 s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
940 #ifdef CONFIG_STACKDEPOT
941 handle = READ_ONCE(t->handle);
943 stack_depot_print(handle);
945 pr_err("object allocation/free stack trace missing\n");
949 void print_tracking(struct kmem_cache *s, void *object)
951 unsigned long pr_time = jiffies;
952 if (!(s->flags & SLAB_STORE_USER))
955 print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
956 print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
959 static void print_slab_info(const struct slab *slab)
961 struct folio *folio = (struct folio *)slab_folio(slab);
963 pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
964 slab, slab->objects, slab->inuse, slab->freelist,
965 folio_flags(folio, 0));
969 * kmalloc caches has fixed sizes (mostly power of 2), and kmalloc() API
970 * family will round up the real request size to these fixed ones, so
971 * there could be an extra area than what is requested. Save the original
972 * request size in the meta data area, for better debug and sanity check.
974 static inline void set_orig_size(struct kmem_cache *s,
975 void *object, unsigned int orig_size)
977 void *p = kasan_reset_tag(object);
978 unsigned int kasan_meta_size;
980 if (!slub_debug_orig_size(s))
984 * KASAN can save its free meta data inside of the object at offset 0.
985 * If this meta data size is larger than 'orig_size', it will overlap
986 * the data redzone in [orig_size+1, object_size]. Thus, we adjust
987 * 'orig_size' to be as at least as big as KASAN's meta data.
989 kasan_meta_size = kasan_metadata_size(s, true);
990 if (kasan_meta_size > orig_size)
991 orig_size = kasan_meta_size;
993 p += get_info_end(s);
994 p += sizeof(struct track) * 2;
996 *(unsigned int *)p = orig_size;
999 static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
1001 void *p = kasan_reset_tag(object);
1003 if (!slub_debug_orig_size(s))
1004 return s->object_size;
1006 p += get_info_end(s);
1007 p += sizeof(struct track) * 2;
1009 return *(unsigned int *)p;
1012 void skip_orig_size_check(struct kmem_cache *s, const void *object)
1014 set_orig_size(s, (void *)object, s->object_size);
1017 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
1019 struct va_format vaf;
1022 va_start(args, fmt);
1025 pr_err("=============================================================================\n");
1026 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
1027 pr_err("-----------------------------------------------------------------------------\n\n");
1032 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
1034 struct va_format vaf;
1037 if (slab_add_kunit_errors())
1040 va_start(args, fmt);
1043 pr_err("FIX %s: %pV\n", s->name, &vaf);
1047 static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
1049 unsigned int off; /* Offset of last byte */
1050 u8 *addr = slab_address(slab);
1052 print_tracking(s, p);
1054 print_slab_info(slab);
1056 pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
1057 p, p - addr, get_freepointer(s, p));
1059 if (s->flags & SLAB_RED_ZONE)
1060 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
1062 else if (p > addr + 16)
1063 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
1065 print_section(KERN_ERR, "Object ", p,
1066 min_t(unsigned int, s->object_size, PAGE_SIZE));
1067 if (s->flags & SLAB_RED_ZONE)
1068 print_section(KERN_ERR, "Redzone ", p + s->object_size,
1069 s->inuse - s->object_size);
1071 off = get_info_end(s);
1073 if (s->flags & SLAB_STORE_USER)
1074 off += 2 * sizeof(struct track);
1076 if (slub_debug_orig_size(s))
1077 off += sizeof(unsigned int);
1079 off += kasan_metadata_size(s, false);
1081 if (off != size_from_object(s))
1082 /* Beginning of the filler is the free pointer */
1083 print_section(KERN_ERR, "Padding ", p + off,
1084 size_from_object(s) - off);
1089 static void object_err(struct kmem_cache *s, struct slab *slab,
1090 u8 *object, char *reason)
1092 if (slab_add_kunit_errors())
1095 slab_bug(s, "%s", reason);
1096 print_trailer(s, slab, object);
1097 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1100 static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1101 void **freelist, void *nextfree)
1103 if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
1104 !check_valid_pointer(s, slab, nextfree) && freelist) {
1105 object_err(s, slab, *freelist, "Freechain corrupt");
1107 slab_fix(s, "Isolate corrupted freechain");
1114 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
1115 const char *fmt, ...)
1120 if (slab_add_kunit_errors())
1123 va_start(args, fmt);
1124 vsnprintf(buf, sizeof(buf), fmt, args);
1126 slab_bug(s, "%s", buf);
1127 print_slab_info(slab);
1129 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1132 static void init_object(struct kmem_cache *s, void *object, u8 val)
1134 u8 *p = kasan_reset_tag(object);
1135 unsigned int poison_size = s->object_size;
1137 if (s->flags & SLAB_RED_ZONE) {
1138 memset(p - s->red_left_pad, val, s->red_left_pad);
1140 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1142 * Redzone the extra allocated space by kmalloc than
1143 * requested, and the poison size will be limited to
1144 * the original request size accordingly.
1146 poison_size = get_orig_size(s, object);
1150 if (s->flags & __OBJECT_POISON) {
1151 memset(p, POISON_FREE, poison_size - 1);
1152 p[poison_size - 1] = POISON_END;
1155 if (s->flags & SLAB_RED_ZONE)
1156 memset(p + poison_size, val, s->inuse - poison_size);
1159 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
1160 void *from, void *to)
1162 slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
1163 memset(from, data, to - from);
1166 static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
1167 u8 *object, char *what,
1168 u8 *start, unsigned int value, unsigned int bytes)
1172 u8 *addr = slab_address(slab);
1174 metadata_access_enable();
1175 fault = memchr_inv(kasan_reset_tag(start), value, bytes);
1176 metadata_access_disable();
1180 end = start + bytes;
1181 while (end > fault && end[-1] == value)
1184 if (slab_add_kunit_errors())
1185 goto skip_bug_print;
1187 slab_bug(s, "%s overwritten", what);
1188 pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
1189 fault, end - 1, fault - addr,
1191 print_trailer(s, slab, object);
1192 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1195 restore_bytes(s, what, value, fault, end);
1203 * Bytes of the object to be managed.
1204 * If the freepointer may overlay the object then the free
1205 * pointer is at the middle of the object.
1207 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
1210 * object + s->object_size
1211 * Padding to reach word boundary. This is also used for Redzoning.
1212 * Padding is extended by another word if Redzoning is enabled and
1213 * object_size == inuse.
1215 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
1216 * 0xcc (RED_ACTIVE) for objects in use.
1219 * Meta data starts here.
1221 * A. Free pointer (if we cannot overwrite object on free)
1222 * B. Tracking data for SLAB_STORE_USER
1223 * C. Original request size for kmalloc object (SLAB_STORE_USER enabled)
1224 * D. Padding to reach required alignment boundary or at minimum
1225 * one word if debugging is on to be able to detect writes
1226 * before the word boundary.
1228 * Padding is done using 0x5a (POISON_INUSE)
1231 * Nothing is used beyond s->size.
1233 * If slabcaches are merged then the object_size and inuse boundaries are mostly
1234 * ignored. And therefore no slab options that rely on these boundaries
1235 * may be used with merged slabcaches.
1238 static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
1240 unsigned long off = get_info_end(s); /* The end of info */
1242 if (s->flags & SLAB_STORE_USER) {
1243 /* We also have user information there */
1244 off += 2 * sizeof(struct track);
1246 if (s->flags & SLAB_KMALLOC)
1247 off += sizeof(unsigned int);
1250 off += kasan_metadata_size(s, false);
1252 if (size_from_object(s) == off)
1255 return check_bytes_and_report(s, slab, p, "Object padding",
1256 p + off, POISON_INUSE, size_from_object(s) - off);
1259 /* Check the pad bytes at the end of a slab page */
1260 static void slab_pad_check(struct kmem_cache *s, struct slab *slab)
1269 if (!(s->flags & SLAB_POISON))
1272 start = slab_address(slab);
1273 length = slab_size(slab);
1274 end = start + length;
1275 remainder = length % s->size;
1279 pad = end - remainder;
1280 metadata_access_enable();
1281 fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
1282 metadata_access_disable();
1285 while (end > fault && end[-1] == POISON_INUSE)
1288 slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
1289 fault, end - 1, fault - start);
1290 print_section(KERN_ERR, "Padding ", pad, remainder);
1292 restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
1295 static int check_object(struct kmem_cache *s, struct slab *slab,
1296 void *object, u8 val)
1299 u8 *endobject = object + s->object_size;
1300 unsigned int orig_size, kasan_meta_size;
1302 if (s->flags & SLAB_RED_ZONE) {
1303 if (!check_bytes_and_report(s, slab, object, "Left Redzone",
1304 object - s->red_left_pad, val, s->red_left_pad))
1307 if (!check_bytes_and_report(s, slab, object, "Right Redzone",
1308 endobject, val, s->inuse - s->object_size))
1311 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1312 orig_size = get_orig_size(s, object);
1314 if (s->object_size > orig_size &&
1315 !check_bytes_and_report(s, slab, object,
1316 "kmalloc Redzone", p + orig_size,
1317 val, s->object_size - orig_size)) {
1322 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
1323 check_bytes_and_report(s, slab, p, "Alignment padding",
1324 endobject, POISON_INUSE,
1325 s->inuse - s->object_size);
1329 if (s->flags & SLAB_POISON) {
1330 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON)) {
1332 * KASAN can save its free meta data inside of the
1333 * object at offset 0. Thus, skip checking the part of
1334 * the redzone that overlaps with the meta data.
1336 kasan_meta_size = kasan_metadata_size(s, true);
1337 if (kasan_meta_size < s->object_size - 1 &&
1338 !check_bytes_and_report(s, slab, p, "Poison",
1339 p + kasan_meta_size, POISON_FREE,
1340 s->object_size - kasan_meta_size - 1))
1342 if (kasan_meta_size < s->object_size &&
1343 !check_bytes_and_report(s, slab, p, "End Poison",
1344 p + s->object_size - 1, POISON_END, 1))
1348 * check_pad_bytes cleans up on its own.
1350 check_pad_bytes(s, slab, p);
1353 if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
1355 * Object and freepointer overlap. Cannot check
1356 * freepointer while object is allocated.
1360 /* Check free pointer validity */
1361 if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
1362 object_err(s, slab, p, "Freepointer corrupt");
1364 * No choice but to zap it and thus lose the remainder
1365 * of the free objects in this slab. May cause
1366 * another error because the object count is now wrong.
1368 set_freepointer(s, p, NULL);
1374 static int check_slab(struct kmem_cache *s, struct slab *slab)
1378 if (!folio_test_slab(slab_folio(slab))) {
1379 slab_err(s, slab, "Not a valid slab page");
1383 maxobj = order_objects(slab_order(slab), s->size);
1384 if (slab->objects > maxobj) {
1385 slab_err(s, slab, "objects %u > max %u",
1386 slab->objects, maxobj);
1389 if (slab->inuse > slab->objects) {
1390 slab_err(s, slab, "inuse %u > max %u",
1391 slab->inuse, slab->objects);
1394 /* Slab_pad_check fixes things up after itself */
1395 slab_pad_check(s, slab);
1400 * Determine if a certain object in a slab is on the freelist. Must hold the
1401 * slab lock to guarantee that the chains are in a consistent state.
1403 static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
1407 void *object = NULL;
1410 fp = slab->freelist;
1411 while (fp && nr <= slab->objects) {
1414 if (!check_valid_pointer(s, slab, fp)) {
1416 object_err(s, slab, object,
1417 "Freechain corrupt");
1418 set_freepointer(s, object, NULL);
1420 slab_err(s, slab, "Freepointer corrupt");
1421 slab->freelist = NULL;
1422 slab->inuse = slab->objects;
1423 slab_fix(s, "Freelist cleared");
1429 fp = get_freepointer(s, object);
1433 max_objects = order_objects(slab_order(slab), s->size);
1434 if (max_objects > MAX_OBJS_PER_PAGE)
1435 max_objects = MAX_OBJS_PER_PAGE;
1437 if (slab->objects != max_objects) {
1438 slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
1439 slab->objects, max_objects);
1440 slab->objects = max_objects;
1441 slab_fix(s, "Number of objects adjusted");
1443 if (slab->inuse != slab->objects - nr) {
1444 slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
1445 slab->inuse, slab->objects - nr);
1446 slab->inuse = slab->objects - nr;
1447 slab_fix(s, "Object count adjusted");
1449 return search == NULL;
1452 static void trace(struct kmem_cache *s, struct slab *slab, void *object,
1455 if (s->flags & SLAB_TRACE) {
1456 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1458 alloc ? "alloc" : "free",
1459 object, slab->inuse,
1463 print_section(KERN_INFO, "Object ", (void *)object,
1471 * Tracking of fully allocated slabs for debugging purposes.
1473 static void add_full(struct kmem_cache *s,
1474 struct kmem_cache_node *n, struct slab *slab)
1476 if (!(s->flags & SLAB_STORE_USER))
1479 lockdep_assert_held(&n->list_lock);
1480 list_add(&slab->slab_list, &n->full);
1483 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
1485 if (!(s->flags & SLAB_STORE_USER))
1488 lockdep_assert_held(&n->list_lock);
1489 list_del(&slab->slab_list);
1492 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1494 return atomic_long_read(&n->nr_slabs);
1497 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1499 struct kmem_cache_node *n = get_node(s, node);
1501 atomic_long_inc(&n->nr_slabs);
1502 atomic_long_add(objects, &n->total_objects);
1504 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1506 struct kmem_cache_node *n = get_node(s, node);
1508 atomic_long_dec(&n->nr_slabs);
1509 atomic_long_sub(objects, &n->total_objects);
1512 /* Object debug checks for alloc/free paths */
1513 static void setup_object_debug(struct kmem_cache *s, void *object)
1515 if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
1518 init_object(s, object, SLUB_RED_INACTIVE);
1519 init_tracking(s, object);
1523 void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
1525 if (!kmem_cache_debug_flags(s, SLAB_POISON))
1528 metadata_access_enable();
1529 memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
1530 metadata_access_disable();
1533 static inline int alloc_consistency_checks(struct kmem_cache *s,
1534 struct slab *slab, void *object)
1536 if (!check_slab(s, slab))
1539 if (!check_valid_pointer(s, slab, object)) {
1540 object_err(s, slab, object, "Freelist Pointer check fails");
1544 if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
1550 static noinline bool alloc_debug_processing(struct kmem_cache *s,
1551 struct slab *slab, void *object, int orig_size)
1553 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1554 if (!alloc_consistency_checks(s, slab, object))
1558 /* Success. Perform special debug activities for allocs */
1559 trace(s, slab, object, 1);
1560 set_orig_size(s, object, orig_size);
1561 init_object(s, object, SLUB_RED_ACTIVE);
1565 if (folio_test_slab(slab_folio(slab))) {
1567 * If this is a slab page then lets do the best we can
1568 * to avoid issues in the future. Marking all objects
1569 * as used avoids touching the remaining objects.
1571 slab_fix(s, "Marking all objects used");
1572 slab->inuse = slab->objects;
1573 slab->freelist = NULL;
1578 static inline int free_consistency_checks(struct kmem_cache *s,
1579 struct slab *slab, void *object, unsigned long addr)
1581 if (!check_valid_pointer(s, slab, object)) {
1582 slab_err(s, slab, "Invalid object pointer 0x%p", object);
1586 if (on_freelist(s, slab, object)) {
1587 object_err(s, slab, object, "Object already free");
1591 if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
1594 if (unlikely(s != slab->slab_cache)) {
1595 if (!folio_test_slab(slab_folio(slab))) {
1596 slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
1598 } else if (!slab->slab_cache) {
1599 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1603 object_err(s, slab, object,
1604 "page slab pointer corrupt.");
1611 * Parse a block of slab_debug options. Blocks are delimited by ';'
1613 * @str: start of block
1614 * @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1615 * @slabs: return start of list of slabs, or NULL when there's no list
1616 * @init: assume this is initial parsing and not per-kmem-create parsing
1618 * returns the start of next block if there's any, or NULL
1621 parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
1623 bool higher_order_disable = false;
1625 /* Skip any completely empty blocks */
1626 while (*str && *str == ';')
1631 * No options but restriction on slabs. This means full
1632 * debugging for slabs matching a pattern.
1634 *flags = DEBUG_DEFAULT_FLAGS;
1639 /* Determine which debug features should be switched on */
1640 for (; *str && *str != ',' && *str != ';'; str++) {
1641 switch (tolower(*str)) {
1646 *flags |= SLAB_CONSISTENCY_CHECKS;
1649 *flags |= SLAB_RED_ZONE;
1652 *flags |= SLAB_POISON;
1655 *flags |= SLAB_STORE_USER;
1658 *flags |= SLAB_TRACE;
1661 *flags |= SLAB_FAILSLAB;
1665 * Avoid enabling debugging on caches if its minimum
1666 * order would increase as a result.
1668 higher_order_disable = true;
1672 pr_err("slab_debug option '%c' unknown. skipped\n", *str);
1681 /* Skip over the slab list */
1682 while (*str && *str != ';')
1685 /* Skip any completely empty blocks */
1686 while (*str && *str == ';')
1689 if (init && higher_order_disable)
1690 disable_higher_order_debug = 1;
1698 static int __init setup_slub_debug(char *str)
1701 slab_flags_t global_flags;
1704 bool global_slub_debug_changed = false;
1705 bool slab_list_specified = false;
1707 global_flags = DEBUG_DEFAULT_FLAGS;
1708 if (*str++ != '=' || !*str)
1710 * No options specified. Switch on full debugging.
1716 str = parse_slub_debug_flags(str, &flags, &slab_list, true);
1719 global_flags = flags;
1720 global_slub_debug_changed = true;
1722 slab_list_specified = true;
1723 if (flags & SLAB_STORE_USER)
1724 stack_depot_request_early_init();
1729 * For backwards compatibility, a single list of flags with list of
1730 * slabs means debugging is only changed for those slabs, so the global
1731 * slab_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
1732 * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
1733 * long as there is no option specifying flags without a slab list.
1735 if (slab_list_specified) {
1736 if (!global_slub_debug_changed)
1737 global_flags = slub_debug;
1738 slub_debug_string = saved_str;
1741 slub_debug = global_flags;
1742 if (slub_debug & SLAB_STORE_USER)
1743 stack_depot_request_early_init();
1744 if (slub_debug != 0 || slub_debug_string)
1745 static_branch_enable(&slub_debug_enabled);
1747 static_branch_disable(&slub_debug_enabled);
1748 if ((static_branch_unlikely(&init_on_alloc) ||
1749 static_branch_unlikely(&init_on_free)) &&
1750 (slub_debug & SLAB_POISON))
1751 pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1755 __setup("slab_debug", setup_slub_debug);
1756 __setup_param("slub_debug", slub_debug, setup_slub_debug, 0);
1759 * kmem_cache_flags - apply debugging options to the cache
1760 * @flags: flags to set
1761 * @name: name of the cache
1763 * Debug option(s) are applied to @flags. In addition to the debug
1764 * option(s), if a slab name (or multiple) is specified i.e.
1765 * slab_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1766 * then only the select slabs will receive the debug option(s).
1768 slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name)
1773 slab_flags_t block_flags;
1774 slab_flags_t slub_debug_local = slub_debug;
1776 if (flags & SLAB_NO_USER_FLAGS)
1780 * If the slab cache is for debugging (e.g. kmemleak) then
1781 * don't store user (stack trace) information by default,
1782 * but let the user enable it via the command line below.
1784 if (flags & SLAB_NOLEAKTRACE)
1785 slub_debug_local &= ~SLAB_STORE_USER;
1788 next_block = slub_debug_string;
1789 /* Go through all blocks of debug options, see if any matches our slab's name */
1790 while (next_block) {
1791 next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
1794 /* Found a block that has a slab list, search it */
1799 end = strchrnul(iter, ',');
1800 if (next_block && next_block < end)
1801 end = next_block - 1;
1803 glob = strnchr(iter, end - iter, '*');
1805 cmplen = glob - iter;
1807 cmplen = max_t(size_t, len, (end - iter));
1809 if (!strncmp(name, iter, cmplen)) {
1810 flags |= block_flags;
1814 if (!*end || *end == ';')
1820 return flags | slub_debug_local;
1822 #else /* !CONFIG_SLUB_DEBUG */
1823 static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
1825 void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
1827 static inline bool alloc_debug_processing(struct kmem_cache *s,
1828 struct slab *slab, void *object, int orig_size) { return true; }
1830 static inline bool free_debug_processing(struct kmem_cache *s,
1831 struct slab *slab, void *head, void *tail, int *bulk_cnt,
1832 unsigned long addr, depot_stack_handle_t handle) { return true; }
1834 static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
1835 static inline int check_object(struct kmem_cache *s, struct slab *slab,
1836 void *object, u8 val) { return 1; }
1837 static inline depot_stack_handle_t set_track_prepare(void) { return 0; }
1838 static inline void set_track(struct kmem_cache *s, void *object,
1839 enum track_item alloc, unsigned long addr) {}
1840 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1841 struct slab *slab) {}
1842 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1843 struct slab *slab) {}
1844 slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name)
1848 #define slub_debug 0
1850 #define disable_higher_order_debug 0
1852 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1854 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1856 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1859 #ifndef CONFIG_SLUB_TINY
1860 static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1861 void **freelist, void *nextfree)
1866 #endif /* CONFIG_SLUB_DEBUG */
1868 static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
1870 return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1871 NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
1874 #ifdef CONFIG_MEMCG_KMEM
1875 static inline void memcg_free_slab_cgroups(struct slab *slab)
1877 kfree(slab_objcgs(slab));
1878 slab->memcg_data = 0;
1881 static inline size_t obj_full_size(struct kmem_cache *s)
1884 * For each accounted object there is an extra space which is used
1885 * to store obj_cgroup membership. Charge it too.
1887 return s->size + sizeof(struct obj_cgroup *);
1891 * Returns false if the allocation should fail.
1893 static bool __memcg_slab_pre_alloc_hook(struct kmem_cache *s,
1894 struct list_lru *lru,
1895 struct obj_cgroup **objcgp,
1896 size_t objects, gfp_t flags)
1899 * The obtained objcg pointer is safe to use within the current scope,
1900 * defined by current task or set_active_memcg() pair.
1901 * obj_cgroup_get() is used to get a permanent reference.
1903 struct obj_cgroup *objcg = current_obj_cgroup();
1909 struct mem_cgroup *memcg;
1911 memcg = get_mem_cgroup_from_objcg(objcg);
1912 ret = memcg_list_lru_alloc(memcg, lru, flags);
1913 css_put(&memcg->css);
1919 if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s)))
1927 * Returns false if the allocation should fail.
1929 static __fastpath_inline
1930 bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
1931 struct obj_cgroup **objcgp, size_t objects,
1934 if (!memcg_kmem_online())
1937 if (likely(!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT)))
1940 return likely(__memcg_slab_pre_alloc_hook(s, lru, objcgp, objects,
1944 static void __memcg_slab_post_alloc_hook(struct kmem_cache *s,
1945 struct obj_cgroup *objcg,
1946 gfp_t flags, size_t size,
1953 flags &= gfp_allowed_mask;
1955 for (i = 0; i < size; i++) {
1957 slab = virt_to_slab(p[i]);
1959 if (!slab_objcgs(slab) &&
1960 memcg_alloc_slab_cgroups(slab, s, flags, false)) {
1961 obj_cgroup_uncharge(objcg, obj_full_size(s));
1965 off = obj_to_index(s, slab, p[i]);
1966 obj_cgroup_get(objcg);
1967 slab_objcgs(slab)[off] = objcg;
1968 mod_objcg_state(objcg, slab_pgdat(slab),
1969 cache_vmstat_idx(s), obj_full_size(s));
1971 obj_cgroup_uncharge(objcg, obj_full_size(s));
1976 static __fastpath_inline
1977 void memcg_slab_post_alloc_hook(struct kmem_cache *s, struct obj_cgroup *objcg,
1978 gfp_t flags, size_t size, void **p)
1980 if (likely(!memcg_kmem_online() || !objcg))
1983 return __memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
1986 static void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
1987 void **p, int objects,
1988 struct obj_cgroup **objcgs)
1990 for (int i = 0; i < objects; i++) {
1991 struct obj_cgroup *objcg;
1994 off = obj_to_index(s, slab, p[i]);
1995 objcg = objcgs[off];
2000 obj_cgroup_uncharge(objcg, obj_full_size(s));
2001 mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
2003 obj_cgroup_put(objcg);
2007 static __fastpath_inline
2008 void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,
2011 struct obj_cgroup **objcgs;
2013 if (!memcg_kmem_online())
2016 objcgs = slab_objcgs(slab);
2017 if (likely(!objcgs))
2020 __memcg_slab_free_hook(s, slab, p, objects, objcgs);
2024 void memcg_slab_alloc_error_hook(struct kmem_cache *s, int objects,
2025 struct obj_cgroup *objcg)
2028 obj_cgroup_uncharge(objcg, objects * obj_full_size(s));
2030 #else /* CONFIG_MEMCG_KMEM */
2031 static inline void memcg_free_slab_cgroups(struct slab *slab)
2035 static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
2036 struct list_lru *lru,
2037 struct obj_cgroup **objcgp,
2038 size_t objects, gfp_t flags)
2043 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
2044 struct obj_cgroup *objcg,
2045 gfp_t flags, size_t size,
2050 static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
2051 void **p, int objects)
2056 void memcg_slab_alloc_error_hook(struct kmem_cache *s, int objects,
2057 struct obj_cgroup *objcg)
2060 #endif /* CONFIG_MEMCG_KMEM */
2063 * Hooks for other subsystems that check memory allocations. In a typical
2064 * production configuration these hooks all should produce no code at all.
2066 * Returns true if freeing of the object can proceed, false if its reuse
2067 * was delayed by KASAN quarantine, or it was returned to KFENCE.
2069 static __always_inline
2070 bool slab_free_hook(struct kmem_cache *s, void *x, bool init)
2072 kmemleak_free_recursive(x, s->flags);
2073 kmsan_slab_free(s, x);
2075 debug_check_no_locks_freed(x, s->object_size);
2077 if (!(s->flags & SLAB_DEBUG_OBJECTS))
2078 debug_check_no_obj_freed(x, s->object_size);
2080 /* Use KCSAN to help debug racy use-after-free. */
2081 if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
2082 __kcsan_check_access(x, s->object_size,
2083 KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
2089 * As memory initialization might be integrated into KASAN,
2090 * kasan_slab_free and initialization memset's must be
2091 * kept together to avoid discrepancies in behavior.
2093 * The initialization memset's clear the object and the metadata,
2094 * but don't touch the SLAB redzone.
2096 if (unlikely(init)) {
2099 if (!kasan_has_integrated_init())
2100 memset(kasan_reset_tag(x), 0, s->object_size);
2101 rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
2102 memset((char *)kasan_reset_tag(x) + s->inuse, 0,
2103 s->size - s->inuse - rsize);
2105 /* KASAN might put x into memory quarantine, delaying its reuse. */
2106 return !kasan_slab_free(s, x, init);
2109 static inline bool slab_free_freelist_hook(struct kmem_cache *s,
2110 void **head, void **tail,
2116 void *old_tail = *tail;
2119 if (is_kfence_address(next)) {
2120 slab_free_hook(s, next, false);
2124 /* Head and tail of the reconstructed freelist */
2128 init = slab_want_init_on_free(s);
2132 next = get_freepointer(s, object);
2134 /* If object's reuse doesn't have to be delayed */
2135 if (likely(slab_free_hook(s, object, init))) {
2136 /* Move object to the new freelist */
2137 set_freepointer(s, object, *head);
2143 * Adjust the reconstructed freelist depth
2144 * accordingly if object's reuse is delayed.
2148 } while (object != old_tail);
2150 return *head != NULL;
2153 static void *setup_object(struct kmem_cache *s, void *object)
2155 setup_object_debug(s, object);
2156 object = kasan_init_slab_obj(s, object);
2157 if (unlikely(s->ctor)) {
2158 kasan_unpoison_new_object(s, object);
2160 kasan_poison_new_object(s, object);
2166 * Slab allocation and freeing
2168 static inline struct slab *alloc_slab_page(gfp_t flags, int node,
2169 struct kmem_cache_order_objects oo)
2171 struct folio *folio;
2173 unsigned int order = oo_order(oo);
2175 folio = (struct folio *)alloc_pages_node(node, flags, order);
2179 slab = folio_slab(folio);
2180 __folio_set_slab(folio);
2181 /* Make the flag visible before any changes to folio->mapping */
2183 if (folio_is_pfmemalloc(folio))
2184 slab_set_pfmemalloc(slab);
2189 #ifdef CONFIG_SLAB_FREELIST_RANDOM
2190 /* Pre-initialize the random sequence cache */
2191 static int init_cache_random_seq(struct kmem_cache *s)
2193 unsigned int count = oo_objects(s->oo);
2196 /* Bailout if already initialised */
2200 err = cache_random_seq_create(s, count, GFP_KERNEL);
2202 pr_err("SLUB: Unable to initialize free list for %s\n",
2207 /* Transform to an offset on the set of pages */
2208 if (s->random_seq) {
2211 for (i = 0; i < count; i++)
2212 s->random_seq[i] *= s->size;
2217 /* Initialize each random sequence freelist per cache */
2218 static void __init init_freelist_randomization(void)
2220 struct kmem_cache *s;
2222 mutex_lock(&slab_mutex);
2224 list_for_each_entry(s, &slab_caches, list)
2225 init_cache_random_seq(s);
2227 mutex_unlock(&slab_mutex);
2230 /* Get the next entry on the pre-computed freelist randomized */
2231 static void *next_freelist_entry(struct kmem_cache *s,
2232 unsigned long *pos, void *start,
2233 unsigned long page_limit,
2234 unsigned long freelist_count)
2239 * If the target page allocation failed, the number of objects on the
2240 * page might be smaller than the usual size defined by the cache.
2243 idx = s->random_seq[*pos];
2245 if (*pos >= freelist_count)
2247 } while (unlikely(idx >= page_limit));
2249 return (char *)start + idx;
2252 /* Shuffle the single linked freelist based on a random pre-computed sequence */
2253 static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
2258 unsigned long idx, pos, page_limit, freelist_count;
2260 if (slab->objects < 2 || !s->random_seq)
2263 freelist_count = oo_objects(s->oo);
2264 pos = get_random_u32_below(freelist_count);
2266 page_limit = slab->objects * s->size;
2267 start = fixup_red_left(s, slab_address(slab));
2269 /* First entry is used as the base of the freelist */
2270 cur = next_freelist_entry(s, &pos, start, page_limit, freelist_count);
2271 cur = setup_object(s, cur);
2272 slab->freelist = cur;
2274 for (idx = 1; idx < slab->objects; idx++) {
2275 next = next_freelist_entry(s, &pos, start, page_limit,
2277 next = setup_object(s, next);
2278 set_freepointer(s, cur, next);
2281 set_freepointer(s, cur, NULL);
2286 static inline int init_cache_random_seq(struct kmem_cache *s)
2290 static inline void init_freelist_randomization(void) { }
2291 static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
2295 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
2297 static __always_inline void account_slab(struct slab *slab, int order,
2298 struct kmem_cache *s, gfp_t gfp)
2300 if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
2301 memcg_alloc_slab_cgroups(slab, s, gfp, true);
2303 mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
2304 PAGE_SIZE << order);
2307 static __always_inline void unaccount_slab(struct slab *slab, int order,
2308 struct kmem_cache *s)
2310 if (memcg_kmem_online())
2311 memcg_free_slab_cgroups(slab);
2313 mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
2314 -(PAGE_SIZE << order));
2317 static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
2320 struct kmem_cache_order_objects oo = s->oo;
2322 void *start, *p, *next;
2326 flags &= gfp_allowed_mask;
2328 flags |= s->allocflags;
2331 * Let the initial higher-order allocation fail under memory pressure
2332 * so we fall-back to the minimum order allocation.
2334 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
2335 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
2336 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
2338 slab = alloc_slab_page(alloc_gfp, node, oo);
2339 if (unlikely(!slab)) {
2343 * Allocation may have failed due to fragmentation.
2344 * Try a lower order alloc if possible
2346 slab = alloc_slab_page(alloc_gfp, node, oo);
2347 if (unlikely(!slab))
2349 stat(s, ORDER_FALLBACK);
2352 slab->objects = oo_objects(oo);
2356 account_slab(slab, oo_order(oo), s, flags);
2358 slab->slab_cache = s;
2360 kasan_poison_slab(slab);
2362 start = slab_address(slab);
2364 setup_slab_debug(s, slab, start);
2366 shuffle = shuffle_freelist(s, slab);
2369 start = fixup_red_left(s, start);
2370 start = setup_object(s, start);
2371 slab->freelist = start;
2372 for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
2374 next = setup_object(s, next);
2375 set_freepointer(s, p, next);
2378 set_freepointer(s, p, NULL);
2384 static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
2386 if (unlikely(flags & GFP_SLAB_BUG_MASK))
2387 flags = kmalloc_fix_flags(flags);
2389 WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2391 return allocate_slab(s,
2392 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
2395 static void __free_slab(struct kmem_cache *s, struct slab *slab)
2397 struct folio *folio = slab_folio(slab);
2398 int order = folio_order(folio);
2399 int pages = 1 << order;
2401 __slab_clear_pfmemalloc(slab);
2402 folio->mapping = NULL;
2403 /* Make the mapping reset visible before clearing the flag */
2405 __folio_clear_slab(folio);
2406 mm_account_reclaimed_pages(pages);
2407 unaccount_slab(slab, order, s);
2408 __free_pages(&folio->page, order);
2411 static void rcu_free_slab(struct rcu_head *h)
2413 struct slab *slab = container_of(h, struct slab, rcu_head);
2415 __free_slab(slab->slab_cache, slab);
2418 static void free_slab(struct kmem_cache *s, struct slab *slab)
2420 if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
2423 slab_pad_check(s, slab);
2424 for_each_object(p, s, slab_address(slab), slab->objects)
2425 check_object(s, slab, p, SLUB_RED_INACTIVE);
2428 if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU))
2429 call_rcu(&slab->rcu_head, rcu_free_slab);
2431 __free_slab(s, slab);
2434 static void discard_slab(struct kmem_cache *s, struct slab *slab)
2436 dec_slabs_node(s, slab_nid(slab), slab->objects);
2441 * SLUB reuses PG_workingset bit to keep track of whether it's on
2442 * the per-node partial list.
2444 static inline bool slab_test_node_partial(const struct slab *slab)
2446 return folio_test_workingset((struct folio *)slab_folio(slab));
2449 static inline void slab_set_node_partial(struct slab *slab)
2451 set_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
2454 static inline void slab_clear_node_partial(struct slab *slab)
2456 clear_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
2460 * Management of partially allocated slabs.
2463 __add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
2466 if (tail == DEACTIVATE_TO_TAIL)
2467 list_add_tail(&slab->slab_list, &n->partial);
2469 list_add(&slab->slab_list, &n->partial);
2470 slab_set_node_partial(slab);
2473 static inline void add_partial(struct kmem_cache_node *n,
2474 struct slab *slab, int tail)
2476 lockdep_assert_held(&n->list_lock);
2477 __add_partial(n, slab, tail);
2480 static inline void remove_partial(struct kmem_cache_node *n,
2483 lockdep_assert_held(&n->list_lock);
2484 list_del(&slab->slab_list);
2485 slab_clear_node_partial(slab);
2490 * Called only for kmem_cache_debug() caches instead of remove_partial(), with a
2491 * slab from the n->partial list. Remove only a single object from the slab, do
2492 * the alloc_debug_processing() checks and leave the slab on the list, or move
2493 * it to full list if it was the last free object.
2495 static void *alloc_single_from_partial(struct kmem_cache *s,
2496 struct kmem_cache_node *n, struct slab *slab, int orig_size)
2500 lockdep_assert_held(&n->list_lock);
2502 object = slab->freelist;
2503 slab->freelist = get_freepointer(s, object);
2506 if (!alloc_debug_processing(s, slab, object, orig_size)) {
2507 remove_partial(n, slab);
2511 if (slab->inuse == slab->objects) {
2512 remove_partial(n, slab);
2513 add_full(s, n, slab);
2520 * Called only for kmem_cache_debug() caches to allocate from a freshly
2521 * allocated slab. Allocate a single object instead of whole freelist
2522 * and put the slab to the partial (or full) list.
2524 static void *alloc_single_from_new_slab(struct kmem_cache *s,
2525 struct slab *slab, int orig_size)
2527 int nid = slab_nid(slab);
2528 struct kmem_cache_node *n = get_node(s, nid);
2529 unsigned long flags;
2533 object = slab->freelist;
2534 slab->freelist = get_freepointer(s, object);
2537 if (!alloc_debug_processing(s, slab, object, orig_size))
2539 * It's not really expected that this would fail on a
2540 * freshly allocated slab, but a concurrent memory
2541 * corruption in theory could cause that.
2545 spin_lock_irqsave(&n->list_lock, flags);
2547 if (slab->inuse == slab->objects)
2548 add_full(s, n, slab);
2550 add_partial(n, slab, DEACTIVATE_TO_HEAD);
2552 inc_slabs_node(s, nid, slab->objects);
2553 spin_unlock_irqrestore(&n->list_lock, flags);
2558 #ifdef CONFIG_SLUB_CPU_PARTIAL
2559 static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
2561 static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
2564 static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
2567 * Try to allocate a partial slab from a specific node.
2569 static struct slab *get_partial_node(struct kmem_cache *s,
2570 struct kmem_cache_node *n,
2571 struct partial_context *pc)
2573 struct slab *slab, *slab2, *partial = NULL;
2574 unsigned long flags;
2575 unsigned int partial_slabs = 0;
2578 * Racy check. If we mistakenly see no partial slabs then we
2579 * just allocate an empty slab. If we mistakenly try to get a
2580 * partial slab and there is none available then get_partial()
2583 if (!n || !n->nr_partial)
2586 spin_lock_irqsave(&n->list_lock, flags);
2587 list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
2588 if (!pfmemalloc_match(slab, pc->flags))
2591 if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
2592 void *object = alloc_single_from_partial(s, n, slab,
2596 pc->object = object;
2602 remove_partial(n, slab);
2606 stat(s, ALLOC_FROM_PARTIAL);
2608 put_cpu_partial(s, slab, 0);
2609 stat(s, CPU_PARTIAL_NODE);
2612 #ifdef CONFIG_SLUB_CPU_PARTIAL
2613 if (!kmem_cache_has_cpu_partial(s)
2614 || partial_slabs > s->cpu_partial_slabs / 2)
2621 spin_unlock_irqrestore(&n->list_lock, flags);
2626 * Get a slab from somewhere. Search in increasing NUMA distances.
2628 static struct slab *get_any_partial(struct kmem_cache *s,
2629 struct partial_context *pc)
2632 struct zonelist *zonelist;
2635 enum zone_type highest_zoneidx = gfp_zone(pc->flags);
2637 unsigned int cpuset_mems_cookie;
2640 * The defrag ratio allows a configuration of the tradeoffs between
2641 * inter node defragmentation and node local allocations. A lower
2642 * defrag_ratio increases the tendency to do local allocations
2643 * instead of attempting to obtain partial slabs from other nodes.
2645 * If the defrag_ratio is set to 0 then kmalloc() always
2646 * returns node local objects. If the ratio is higher then kmalloc()
2647 * may return off node objects because partial slabs are obtained
2648 * from other nodes and filled up.
2650 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2651 * (which makes defrag_ratio = 1000) then every (well almost)
2652 * allocation will first attempt to defrag slab caches on other nodes.
2653 * This means scanning over all nodes to look for partial slabs which
2654 * may be expensive if we do it every time we are trying to find a slab
2655 * with available objects.
2657 if (!s->remote_node_defrag_ratio ||
2658 get_cycles() % 1024 > s->remote_node_defrag_ratio)
2662 cpuset_mems_cookie = read_mems_allowed_begin();
2663 zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
2664 for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
2665 struct kmem_cache_node *n;
2667 n = get_node(s, zone_to_nid(zone));
2669 if (n && cpuset_zone_allowed(zone, pc->flags) &&
2670 n->nr_partial > s->min_partial) {
2671 slab = get_partial_node(s, n, pc);
2674 * Don't check read_mems_allowed_retry()
2675 * here - if mems_allowed was updated in
2676 * parallel, that was a harmless race
2677 * between allocation and the cpuset
2684 } while (read_mems_allowed_retry(cpuset_mems_cookie));
2685 #endif /* CONFIG_NUMA */
2690 * Get a partial slab, lock it and return it.
2692 static struct slab *get_partial(struct kmem_cache *s, int node,
2693 struct partial_context *pc)
2696 int searchnode = node;
2698 if (node == NUMA_NO_NODE)
2699 searchnode = numa_mem_id();
2701 slab = get_partial_node(s, get_node(s, searchnode), pc);
2702 if (slab || node != NUMA_NO_NODE)
2705 return get_any_partial(s, pc);
2708 #ifndef CONFIG_SLUB_TINY
2710 #ifdef CONFIG_PREEMPTION
2712 * Calculate the next globally unique transaction for disambiguation
2713 * during cmpxchg. The transactions start with the cpu number and are then
2714 * incremented by CONFIG_NR_CPUS.
2716 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
2719 * No preemption supported therefore also no need to check for
2723 #endif /* CONFIG_PREEMPTION */
2725 static inline unsigned long next_tid(unsigned long tid)
2727 return tid + TID_STEP;
2730 #ifdef SLUB_DEBUG_CMPXCHG
2731 static inline unsigned int tid_to_cpu(unsigned long tid)
2733 return tid % TID_STEP;
2736 static inline unsigned long tid_to_event(unsigned long tid)
2738 return tid / TID_STEP;
2742 static inline unsigned int init_tid(int cpu)
2747 static inline void note_cmpxchg_failure(const char *n,
2748 const struct kmem_cache *s, unsigned long tid)
2750 #ifdef SLUB_DEBUG_CMPXCHG
2751 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2753 pr_info("%s %s: cmpxchg redo ", n, s->name);
2755 #ifdef CONFIG_PREEMPTION
2756 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2757 pr_warn("due to cpu change %d -> %d\n",
2758 tid_to_cpu(tid), tid_to_cpu(actual_tid));
2761 if (tid_to_event(tid) != tid_to_event(actual_tid))
2762 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2763 tid_to_event(tid), tid_to_event(actual_tid));
2765 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2766 actual_tid, tid, next_tid(tid));
2768 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2771 static void init_kmem_cache_cpus(struct kmem_cache *s)
2774 struct kmem_cache_cpu *c;
2776 for_each_possible_cpu(cpu) {
2777 c = per_cpu_ptr(s->cpu_slab, cpu);
2778 local_lock_init(&c->lock);
2779 c->tid = init_tid(cpu);
2784 * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
2785 * unfreezes the slabs and puts it on the proper list.
2786 * Assumes the slab has been already safely taken away from kmem_cache_cpu
2789 static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
2792 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
2794 void *nextfree, *freelist_iter, *freelist_tail;
2795 int tail = DEACTIVATE_TO_HEAD;
2796 unsigned long flags = 0;
2800 if (slab->freelist) {
2801 stat(s, DEACTIVATE_REMOTE_FREES);
2802 tail = DEACTIVATE_TO_TAIL;
2806 * Stage one: Count the objects on cpu's freelist as free_delta and
2807 * remember the last object in freelist_tail for later splicing.
2809 freelist_tail = NULL;
2810 freelist_iter = freelist;
2811 while (freelist_iter) {
2812 nextfree = get_freepointer(s, freelist_iter);
2815 * If 'nextfree' is invalid, it is possible that the object at
2816 * 'freelist_iter' is already corrupted. So isolate all objects
2817 * starting at 'freelist_iter' by skipping them.
2819 if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
2822 freelist_tail = freelist_iter;
2825 freelist_iter = nextfree;
2829 * Stage two: Unfreeze the slab while splicing the per-cpu
2830 * freelist to the head of slab's freelist.
2833 old.freelist = READ_ONCE(slab->freelist);
2834 old.counters = READ_ONCE(slab->counters);
2835 VM_BUG_ON(!old.frozen);
2837 /* Determine target state of the slab */
2838 new.counters = old.counters;
2840 if (freelist_tail) {
2841 new.inuse -= free_delta;
2842 set_freepointer(s, freelist_tail, old.freelist);
2843 new.freelist = freelist;
2845 new.freelist = old.freelist;
2847 } while (!slab_update_freelist(s, slab,
2848 old.freelist, old.counters,
2849 new.freelist, new.counters,
2850 "unfreezing slab"));
2853 * Stage three: Manipulate the slab list based on the updated state.
2855 if (!new.inuse && n->nr_partial >= s->min_partial) {
2856 stat(s, DEACTIVATE_EMPTY);
2857 discard_slab(s, slab);
2859 } else if (new.freelist) {
2860 spin_lock_irqsave(&n->list_lock, flags);
2861 add_partial(n, slab, tail);
2862 spin_unlock_irqrestore(&n->list_lock, flags);
2865 stat(s, DEACTIVATE_FULL);
2869 #ifdef CONFIG_SLUB_CPU_PARTIAL
2870 static void __put_partials(struct kmem_cache *s, struct slab *partial_slab)
2872 struct kmem_cache_node *n = NULL, *n2 = NULL;
2873 struct slab *slab, *slab_to_discard = NULL;
2874 unsigned long flags = 0;
2876 while (partial_slab) {
2877 slab = partial_slab;
2878 partial_slab = slab->next;
2880 n2 = get_node(s, slab_nid(slab));
2883 spin_unlock_irqrestore(&n->list_lock, flags);
2886 spin_lock_irqsave(&n->list_lock, flags);
2889 if (unlikely(!slab->inuse && n->nr_partial >= s->min_partial)) {
2890 slab->next = slab_to_discard;
2891 slab_to_discard = slab;
2893 add_partial(n, slab, DEACTIVATE_TO_TAIL);
2894 stat(s, FREE_ADD_PARTIAL);
2899 spin_unlock_irqrestore(&n->list_lock, flags);
2901 while (slab_to_discard) {
2902 slab = slab_to_discard;
2903 slab_to_discard = slab_to_discard->next;
2905 stat(s, DEACTIVATE_EMPTY);
2906 discard_slab(s, slab);
2912 * Put all the cpu partial slabs to the node partial list.
2914 static void put_partials(struct kmem_cache *s)
2916 struct slab *partial_slab;
2917 unsigned long flags;
2919 local_lock_irqsave(&s->cpu_slab->lock, flags);
2920 partial_slab = this_cpu_read(s->cpu_slab->partial);
2921 this_cpu_write(s->cpu_slab->partial, NULL);
2922 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2925 __put_partials(s, partial_slab);
2928 static void put_partials_cpu(struct kmem_cache *s,
2929 struct kmem_cache_cpu *c)
2931 struct slab *partial_slab;
2933 partial_slab = slub_percpu_partial(c);
2937 __put_partials(s, partial_slab);
2941 * Put a slab into a partial slab slot if available.
2943 * If we did not find a slot then simply move all the partials to the
2944 * per node partial list.
2946 static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
2948 struct slab *oldslab;
2949 struct slab *slab_to_put = NULL;
2950 unsigned long flags;
2953 local_lock_irqsave(&s->cpu_slab->lock, flags);
2955 oldslab = this_cpu_read(s->cpu_slab->partial);
2958 if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
2960 * Partial array is full. Move the existing set to the
2961 * per node partial list. Postpone the actual unfreezing
2962 * outside of the critical section.
2964 slab_to_put = oldslab;
2967 slabs = oldslab->slabs;
2973 slab->slabs = slabs;
2974 slab->next = oldslab;
2976 this_cpu_write(s->cpu_slab->partial, slab);
2978 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2981 __put_partials(s, slab_to_put);
2982 stat(s, CPU_PARTIAL_DRAIN);
2986 #else /* CONFIG_SLUB_CPU_PARTIAL */
2988 static inline void put_partials(struct kmem_cache *s) { }
2989 static inline void put_partials_cpu(struct kmem_cache *s,
2990 struct kmem_cache_cpu *c) { }
2992 #endif /* CONFIG_SLUB_CPU_PARTIAL */
2994 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2996 unsigned long flags;
3000 local_lock_irqsave(&s->cpu_slab->lock, flags);
3003 freelist = c->freelist;
3007 c->tid = next_tid(c->tid);
3009 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3012 deactivate_slab(s, slab, freelist);
3013 stat(s, CPUSLAB_FLUSH);
3017 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
3019 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
3020 void *freelist = c->freelist;
3021 struct slab *slab = c->slab;
3025 c->tid = next_tid(c->tid);
3028 deactivate_slab(s, slab, freelist);
3029 stat(s, CPUSLAB_FLUSH);
3032 put_partials_cpu(s, c);
3035 struct slub_flush_work {
3036 struct work_struct work;
3037 struct kmem_cache *s;
3044 * Called from CPU work handler with migration disabled.
3046 static void flush_cpu_slab(struct work_struct *w)
3048 struct kmem_cache *s;
3049 struct kmem_cache_cpu *c;
3050 struct slub_flush_work *sfw;
3052 sfw = container_of(w, struct slub_flush_work, work);
3055 c = this_cpu_ptr(s->cpu_slab);
3063 static bool has_cpu_slab(int cpu, struct kmem_cache *s)
3065 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
3067 return c->slab || slub_percpu_partial(c);
3070 static DEFINE_MUTEX(flush_lock);
3071 static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
3073 static void flush_all_cpus_locked(struct kmem_cache *s)
3075 struct slub_flush_work *sfw;
3078 lockdep_assert_cpus_held();
3079 mutex_lock(&flush_lock);
3081 for_each_online_cpu(cpu) {
3082 sfw = &per_cpu(slub_flush, cpu);
3083 if (!has_cpu_slab(cpu, s)) {
3087 INIT_WORK(&sfw->work, flush_cpu_slab);
3090 queue_work_on(cpu, flushwq, &sfw->work);
3093 for_each_online_cpu(cpu) {
3094 sfw = &per_cpu(slub_flush, cpu);
3097 flush_work(&sfw->work);
3100 mutex_unlock(&flush_lock);
3103 static void flush_all(struct kmem_cache *s)
3106 flush_all_cpus_locked(s);
3111 * Use the cpu notifier to insure that the cpu slabs are flushed when
3114 static int slub_cpu_dead(unsigned int cpu)
3116 struct kmem_cache *s;
3118 mutex_lock(&slab_mutex);
3119 list_for_each_entry(s, &slab_caches, list)
3120 __flush_cpu_slab(s, cpu);
3121 mutex_unlock(&slab_mutex);
3125 #else /* CONFIG_SLUB_TINY */
3126 static inline void flush_all_cpus_locked(struct kmem_cache *s) { }
3127 static inline void flush_all(struct kmem_cache *s) { }
3128 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { }
3129 static inline int slub_cpu_dead(unsigned int cpu) { return 0; }
3130 #endif /* CONFIG_SLUB_TINY */
3133 * Check if the objects in a per cpu structure fit numa
3134 * locality expectations.
3136 static inline int node_match(struct slab *slab, int node)
3139 if (node != NUMA_NO_NODE && slab_nid(slab) != node)
3145 #ifdef CONFIG_SLUB_DEBUG
3146 static int count_free(struct slab *slab)
3148 return slab->objects - slab->inuse;
3151 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
3153 return atomic_long_read(&n->total_objects);
3156 /* Supports checking bulk free of a constructed freelist */
3157 static inline bool free_debug_processing(struct kmem_cache *s,
3158 struct slab *slab, void *head, void *tail, int *bulk_cnt,
3159 unsigned long addr, depot_stack_handle_t handle)
3161 bool checks_ok = false;
3162 void *object = head;
3165 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
3166 if (!check_slab(s, slab))
3170 if (slab->inuse < *bulk_cnt) {
3171 slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n",
3172 slab->inuse, *bulk_cnt);
3178 if (++cnt > *bulk_cnt)
3181 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
3182 if (!free_consistency_checks(s, slab, object, addr))
3186 if (s->flags & SLAB_STORE_USER)
3187 set_track_update(s, object, TRACK_FREE, addr, handle);
3188 trace(s, slab, object, 0);
3189 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
3190 init_object(s, object, SLUB_RED_INACTIVE);
3192 /* Reached end of constructed freelist yet? */
3193 if (object != tail) {
3194 object = get_freepointer(s, object);
3200 if (cnt != *bulk_cnt) {
3201 slab_err(s, slab, "Bulk free expected %d objects but found %d\n",
3209 slab_fix(s, "Object at 0x%p not freed", object);
3213 #endif /* CONFIG_SLUB_DEBUG */
3215 #if defined(CONFIG_SLUB_DEBUG) || defined(SLAB_SUPPORTS_SYSFS)
3216 static unsigned long count_partial(struct kmem_cache_node *n,
3217 int (*get_count)(struct slab *))
3219 unsigned long flags;
3220 unsigned long x = 0;
3223 spin_lock_irqsave(&n->list_lock, flags);
3224 list_for_each_entry(slab, &n->partial, slab_list)
3225 x += get_count(slab);
3226 spin_unlock_irqrestore(&n->list_lock, flags);
3229 #endif /* CONFIG_SLUB_DEBUG || SLAB_SUPPORTS_SYSFS */
3231 #ifdef CONFIG_SLUB_DEBUG
3232 static noinline void
3233 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
3235 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
3236 DEFAULT_RATELIMIT_BURST);
3238 struct kmem_cache_node *n;
3240 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
3243 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
3244 nid, gfpflags, &gfpflags);
3245 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
3246 s->name, s->object_size, s->size, oo_order(s->oo),
3249 if (oo_order(s->min) > get_order(s->object_size))
3250 pr_warn(" %s debugging increased min order, use slab_debug=O to disable.\n",
3253 for_each_kmem_cache_node(s, node, n) {
3254 unsigned long nr_slabs;
3255 unsigned long nr_objs;
3256 unsigned long nr_free;
3258 nr_free = count_partial(n, count_free);
3259 nr_slabs = node_nr_slabs(n);
3260 nr_objs = node_nr_objs(n);
3262 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
3263 node, nr_slabs, nr_objs, nr_free);
3266 #else /* CONFIG_SLUB_DEBUG */
3268 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) { }
3271 static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
3273 if (unlikely(slab_test_pfmemalloc(slab)))
3274 return gfp_pfmemalloc_allowed(gfpflags);
3279 #ifndef CONFIG_SLUB_TINY
3281 __update_cpu_freelist_fast(struct kmem_cache *s,
3282 void *freelist_old, void *freelist_new,
3285 freelist_aba_t old = { .freelist = freelist_old, .counter = tid };
3286 freelist_aba_t new = { .freelist = freelist_new, .counter = next_tid(tid) };
3288 return this_cpu_try_cmpxchg_freelist(s->cpu_slab->freelist_tid.full,
3289 &old.full, new.full);
3293 * Check the slab->freelist and either transfer the freelist to the
3294 * per cpu freelist or deactivate the slab.
3296 * The slab is still frozen if the return value is not NULL.
3298 * If this function returns NULL then the slab has been unfrozen.
3300 static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
3303 unsigned long counters;
3306 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3309 freelist = slab->freelist;
3310 counters = slab->counters;
3312 new.counters = counters;
3314 new.inuse = slab->objects;
3315 new.frozen = freelist != NULL;
3317 } while (!__slab_update_freelist(s, slab,
3326 * Freeze the partial slab and return the pointer to the freelist.
3328 static inline void *freeze_slab(struct kmem_cache *s, struct slab *slab)
3331 unsigned long counters;
3335 freelist = slab->freelist;
3336 counters = slab->counters;
3338 new.counters = counters;
3339 VM_BUG_ON(new.frozen);
3341 new.inuse = slab->objects;
3344 } while (!slab_update_freelist(s, slab,
3353 * Slow path. The lockless freelist is empty or we need to perform
3356 * Processing is still very fast if new objects have been freed to the
3357 * regular freelist. In that case we simply take over the regular freelist
3358 * as the lockless freelist and zap the regular freelist.
3360 * If that is not working then we fall back to the partial lists. We take the
3361 * first element of the freelist as the object to allocate now and move the
3362 * rest of the freelist to the lockless freelist.
3364 * And if we were unable to get a new slab from the partial slab lists then
3365 * we need to allocate a new slab. This is the slowest path since it involves
3366 * a call to the page allocator and the setup of a new slab.
3368 * Version of __slab_alloc to use when we know that preemption is
3369 * already disabled (which is the case for bulk allocation).
3371 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3372 unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3376 unsigned long flags;
3377 struct partial_context pc;
3379 stat(s, ALLOC_SLOWPATH);
3383 slab = READ_ONCE(c->slab);
3386 * if the node is not online or has no normal memory, just
3387 * ignore the node constraint
3389 if (unlikely(node != NUMA_NO_NODE &&
3390 !node_isset(node, slab_nodes)))
3391 node = NUMA_NO_NODE;
3395 if (unlikely(!node_match(slab, node))) {
3397 * same as above but node_match() being false already
3398 * implies node != NUMA_NO_NODE
3400 if (!node_isset(node, slab_nodes)) {
3401 node = NUMA_NO_NODE;
3403 stat(s, ALLOC_NODE_MISMATCH);
3404 goto deactivate_slab;
3409 * By rights, we should be searching for a slab page that was
3410 * PFMEMALLOC but right now, we are losing the pfmemalloc
3411 * information when the page leaves the per-cpu allocator
3413 if (unlikely(!pfmemalloc_match(slab, gfpflags)))
3414 goto deactivate_slab;
3416 /* must check again c->slab in case we got preempted and it changed */
3417 local_lock_irqsave(&s->cpu_slab->lock, flags);
3418 if (unlikely(slab != c->slab)) {
3419 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3422 freelist = c->freelist;
3426 freelist = get_freelist(s, slab);
3430 c->tid = next_tid(c->tid);
3431 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3432 stat(s, DEACTIVATE_BYPASS);
3436 stat(s, ALLOC_REFILL);
3440 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3443 * freelist is pointing to the list of objects to be used.
3444 * slab is pointing to the slab from which the objects are obtained.
3445 * That slab must be frozen for per cpu allocations to work.
3447 VM_BUG_ON(!c->slab->frozen);
3448 c->freelist = get_freepointer(s, freelist);
3449 c->tid = next_tid(c->tid);
3450 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3455 local_lock_irqsave(&s->cpu_slab->lock, flags);
3456 if (slab != c->slab) {
3457 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3460 freelist = c->freelist;
3463 c->tid = next_tid(c->tid);
3464 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3465 deactivate_slab(s, slab, freelist);
3469 #ifdef CONFIG_SLUB_CPU_PARTIAL
3470 while (slub_percpu_partial(c)) {
3471 local_lock_irqsave(&s->cpu_slab->lock, flags);
3472 if (unlikely(c->slab)) {
3473 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3476 if (unlikely(!slub_percpu_partial(c))) {
3477 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3478 /* we were preempted and partial list got empty */
3482 slab = slub_percpu_partial(c);
3483 slub_set_percpu_partial(c, slab);
3485 if (likely(node_match(slab, node) &&
3486 pfmemalloc_match(slab, gfpflags))) {
3488 freelist = get_freelist(s, slab);
3489 VM_BUG_ON(!freelist);
3490 stat(s, CPU_PARTIAL_ALLOC);
3494 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3497 __put_partials(s, slab);
3503 pc.flags = gfpflags;
3504 pc.orig_size = orig_size;
3505 slab = get_partial(s, node, &pc);
3507 if (kmem_cache_debug(s)) {
3508 freelist = pc.object;
3510 * For debug caches here we had to go through
3511 * alloc_single_from_partial() so just store the
3512 * tracking info and return the object.
3514 if (s->flags & SLAB_STORE_USER)
3515 set_track(s, freelist, TRACK_ALLOC, addr);
3520 freelist = freeze_slab(s, slab);
3521 goto retry_load_slab;
3524 slub_put_cpu_ptr(s->cpu_slab);
3525 slab = new_slab(s, gfpflags, node);
3526 c = slub_get_cpu_ptr(s->cpu_slab);
3528 if (unlikely(!slab)) {
3529 slab_out_of_memory(s, gfpflags, node);
3533 stat(s, ALLOC_SLAB);
3535 if (kmem_cache_debug(s)) {
3536 freelist = alloc_single_from_new_slab(s, slab, orig_size);
3538 if (unlikely(!freelist))
3541 if (s->flags & SLAB_STORE_USER)
3542 set_track(s, freelist, TRACK_ALLOC, addr);
3548 * No other reference to the slab yet so we can
3549 * muck around with it freely without cmpxchg
3551 freelist = slab->freelist;
3552 slab->freelist = NULL;
3553 slab->inuse = slab->objects;
3556 inc_slabs_node(s, slab_nid(slab), slab->objects);
3558 if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
3560 * For !pfmemalloc_match() case we don't load freelist so that
3561 * we don't make further mismatched allocations easier.
3563 deactivate_slab(s, slab, get_freepointer(s, freelist));
3569 local_lock_irqsave(&s->cpu_slab->lock, flags);
3570 if (unlikely(c->slab)) {
3571 void *flush_freelist = c->freelist;
3572 struct slab *flush_slab = c->slab;
3576 c->tid = next_tid(c->tid);
3578 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3580 deactivate_slab(s, flush_slab, flush_freelist);
3582 stat(s, CPUSLAB_FLUSH);
3584 goto retry_load_slab;
3592 * A wrapper for ___slab_alloc() for contexts where preemption is not yet
3593 * disabled. Compensates for possible cpu changes by refetching the per cpu area
3596 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3597 unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3601 #ifdef CONFIG_PREEMPT_COUNT
3603 * We may have been preempted and rescheduled on a different
3604 * cpu before disabling preemption. Need to reload cpu area
3607 c = slub_get_cpu_ptr(s->cpu_slab);
3610 p = ___slab_alloc(s, gfpflags, node, addr, c, orig_size);
3611 #ifdef CONFIG_PREEMPT_COUNT
3612 slub_put_cpu_ptr(s->cpu_slab);
3617 static __always_inline void *__slab_alloc_node(struct kmem_cache *s,
3618 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3620 struct kmem_cache_cpu *c;
3627 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
3628 * enabled. We may switch back and forth between cpus while
3629 * reading from one cpu area. That does not matter as long
3630 * as we end up on the original cpu again when doing the cmpxchg.
3632 * We must guarantee that tid and kmem_cache_cpu are retrieved on the
3633 * same cpu. We read first the kmem_cache_cpu pointer and use it to read
3634 * the tid. If we are preempted and switched to another cpu between the
3635 * two reads, it's OK as the two are still associated with the same cpu
3636 * and cmpxchg later will validate the cpu.
3638 c = raw_cpu_ptr(s->cpu_slab);
3639 tid = READ_ONCE(c->tid);
3642 * Irqless object alloc/free algorithm used here depends on sequence
3643 * of fetching cpu_slab's data. tid should be fetched before anything
3644 * on c to guarantee that object and slab associated with previous tid
3645 * won't be used with current tid. If we fetch tid first, object and
3646 * slab could be one associated with next tid and our alloc/free
3647 * request will be failed. In this case, we will retry. So, no problem.
3652 * The transaction ids are globally unique per cpu and per operation on
3653 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
3654 * occurs on the right processor and that there was no operation on the
3655 * linked list in between.
3658 object = c->freelist;
3661 if (!USE_LOCKLESS_FAST_PATH() ||
3662 unlikely(!object || !slab || !node_match(slab, node))) {
3663 object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
3665 void *next_object = get_freepointer_safe(s, object);
3668 * The cmpxchg will only match if there was no additional
3669 * operation and if we are on the right processor.
3671 * The cmpxchg does the following atomically (without lock
3673 * 1. Relocate first pointer to the current per cpu area.
3674 * 2. Verify that tid and freelist have not been changed
3675 * 3. If they were not changed replace tid and freelist
3677 * Since this is without lock semantics the protection is only
3678 * against code executing on this cpu *not* from access by
3681 if (unlikely(!__update_cpu_freelist_fast(s, object, next_object, tid))) {
3682 note_cmpxchg_failure("slab_alloc", s, tid);
3685 prefetch_freepointer(s, next_object);
3686 stat(s, ALLOC_FASTPATH);
3691 #else /* CONFIG_SLUB_TINY */
3692 static void *__slab_alloc_node(struct kmem_cache *s,
3693 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3695 struct partial_context pc;
3699 pc.flags = gfpflags;
3700 pc.orig_size = orig_size;
3701 slab = get_partial(s, node, &pc);
3706 slab = new_slab(s, gfpflags, node);
3707 if (unlikely(!slab)) {
3708 slab_out_of_memory(s, gfpflags, node);
3712 object = alloc_single_from_new_slab(s, slab, orig_size);
3716 #endif /* CONFIG_SLUB_TINY */
3719 * If the object has been wiped upon free, make sure it's fully initialized by
3720 * zeroing out freelist pointer.
3722 static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
3725 if (unlikely(slab_want_init_on_free(s)) && obj)
3726 memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
3730 noinline int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
3732 if (__should_failslab(s, gfpflags))
3736 ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
3738 static __fastpath_inline
3739 struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
3740 struct list_lru *lru,
3741 struct obj_cgroup **objcgp,
3742 size_t size, gfp_t flags)
3744 flags &= gfp_allowed_mask;
3748 if (unlikely(should_failslab(s, flags)))
3751 if (unlikely(!memcg_slab_pre_alloc_hook(s, lru, objcgp, size, flags)))
3757 static __fastpath_inline
3758 void slab_post_alloc_hook(struct kmem_cache *s, struct obj_cgroup *objcg,
3759 gfp_t flags, size_t size, void **p, bool init,
3760 unsigned int orig_size)
3762 unsigned int zero_size = s->object_size;
3763 bool kasan_init = init;
3765 gfp_t init_flags = flags & gfp_allowed_mask;
3768 * For kmalloc object, the allocated memory size(object_size) is likely
3769 * larger than the requested size(orig_size). If redzone check is
3770 * enabled for the extra space, don't zero it, as it will be redzoned
3771 * soon. The redzone operation for this extra space could be seen as a
3772 * replacement of current poisoning under certain debug option, and
3773 * won't break other sanity checks.
3775 if (kmem_cache_debug_flags(s, SLAB_STORE_USER | SLAB_RED_ZONE) &&
3776 (s->flags & SLAB_KMALLOC))
3777 zero_size = orig_size;
3780 * When slab_debug is enabled, avoid memory initialization integrated
3781 * into KASAN and instead zero out the memory via the memset below with
3782 * the proper size. Otherwise, KASAN might overwrite SLUB redzones and
3783 * cause false-positive reports. This does not lead to a performance
3784 * penalty on production builds, as slab_debug is not intended to be
3787 if (__slub_debug_enabled())
3791 * As memory initialization might be integrated into KASAN,
3792 * kasan_slab_alloc and initialization memset must be
3793 * kept together to avoid discrepancies in behavior.
3795 * As p[i] might get tagged, memset and kmemleak hook come after KASAN.
3797 for (i = 0; i < size; i++) {
3798 p[i] = kasan_slab_alloc(s, p[i], init_flags, kasan_init);
3799 if (p[i] && init && (!kasan_init ||
3800 !kasan_has_integrated_init()))
3801 memset(p[i], 0, zero_size);
3802 kmemleak_alloc_recursive(p[i], s->object_size, 1,
3803 s->flags, init_flags);
3804 kmsan_slab_alloc(s, p[i], init_flags);
3807 memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
3811 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
3812 * have the fastpath folded into their functions. So no function call
3813 * overhead for requests that can be satisfied on the fastpath.
3815 * The fastpath works by first checking if the lockless freelist can be used.
3816 * If not then __slab_alloc is called for slow processing.
3818 * Otherwise we can simply pick the next object from the lockless free list.
3820 static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
3821 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3824 struct obj_cgroup *objcg = NULL;
3827 s = slab_pre_alloc_hook(s, lru, &objcg, 1, gfpflags);
3831 object = kfence_alloc(s, orig_size, gfpflags);
3832 if (unlikely(object))
3835 object = __slab_alloc_node(s, gfpflags, node, addr, orig_size);
3837 maybe_wipe_obj_freeptr(s, object);
3838 init = slab_want_init_on_alloc(gfpflags, s);
3842 * When init equals 'true', like for kzalloc() family, only
3843 * @orig_size bytes might be zeroed instead of s->object_size
3845 slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init, orig_size);
3850 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
3852 void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE, _RET_IP_,
3855 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
3859 EXPORT_SYMBOL(kmem_cache_alloc);
3861 void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
3864 void *ret = slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, _RET_IP_,
3867 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
3871 EXPORT_SYMBOL(kmem_cache_alloc_lru);
3874 * kmem_cache_alloc_node - Allocate an object on the specified node
3875 * @s: The cache to allocate from.
3876 * @gfpflags: See kmalloc().
3877 * @node: node number of the target node.
3879 * Identical to kmem_cache_alloc but it will allocate memory on the given
3880 * node, which can improve the performance for cpu bound structures.
3882 * Fallback to other node is possible if __GFP_THISNODE is not set.
3884 * Return: pointer to the new object or %NULL in case of error
3886 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
3888 void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
3890 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
3894 EXPORT_SYMBOL(kmem_cache_alloc_node);
3897 * To avoid unnecessary overhead, we pass through large allocation requests
3898 * directly to the page allocator. We use __GFP_COMP, because we will need to
3899 * know the allocation order to free the pages properly in kfree.
3901 static void *__kmalloc_large_node(size_t size, gfp_t flags, int node)
3903 struct folio *folio;
3905 unsigned int order = get_order(size);
3907 if (unlikely(flags & GFP_SLAB_BUG_MASK))
3908 flags = kmalloc_fix_flags(flags);
3910 flags |= __GFP_COMP;
3911 folio = (struct folio *)alloc_pages_node(node, flags, order);
3913 ptr = folio_address(folio);
3914 lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
3915 PAGE_SIZE << order);
3918 ptr = kasan_kmalloc_large(ptr, size, flags);
3919 /* As ptr might get tagged, call kmemleak hook after KASAN. */
3920 kmemleak_alloc(ptr, size, 1, flags);
3921 kmsan_kmalloc_large(ptr, size, flags);
3926 void *kmalloc_large(size_t size, gfp_t flags)
3928 void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE);
3930 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
3931 flags, NUMA_NO_NODE);
3934 EXPORT_SYMBOL(kmalloc_large);
3936 void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3938 void *ret = __kmalloc_large_node(size, flags, node);
3940 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
3944 EXPORT_SYMBOL(kmalloc_large_node);
3946 static __always_inline
3947 void *__do_kmalloc_node(size_t size, gfp_t flags, int node,
3948 unsigned long caller)
3950 struct kmem_cache *s;
3953 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3954 ret = __kmalloc_large_node(size, flags, node);
3955 trace_kmalloc(caller, ret, size,
3956 PAGE_SIZE << get_order(size), flags, node);
3960 if (unlikely(!size))
3961 return ZERO_SIZE_PTR;
3963 s = kmalloc_slab(size, flags, caller);
3965 ret = slab_alloc_node(s, NULL, flags, node, caller, size);
3966 ret = kasan_kmalloc(s, ret, size, flags);
3967 trace_kmalloc(caller, ret, size, s->size, flags, node);
3971 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3973 return __do_kmalloc_node(size, flags, node, _RET_IP_);
3975 EXPORT_SYMBOL(__kmalloc_node);
3977 void *__kmalloc(size_t size, gfp_t flags)
3979 return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_);
3981 EXPORT_SYMBOL(__kmalloc);
3983 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3984 int node, unsigned long caller)
3986 return __do_kmalloc_node(size, flags, node, caller);
3988 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3990 void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
3992 void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE,
3995 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);
3997 ret = kasan_kmalloc(s, ret, size, gfpflags);
4000 EXPORT_SYMBOL(kmalloc_trace);
4002 void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
4003 int node, size_t size)
4005 void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, size);
4007 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);
4009 ret = kasan_kmalloc(s, ret, size, gfpflags);
4012 EXPORT_SYMBOL(kmalloc_node_trace);
4014 static noinline void free_to_partial_list(
4015 struct kmem_cache *s, struct slab *slab,
4016 void *head, void *tail, int bulk_cnt,
4019 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
4020 struct slab *slab_free = NULL;
4022 unsigned long flags;
4023 depot_stack_handle_t handle = 0;
4025 if (s->flags & SLAB_STORE_USER)
4026 handle = set_track_prepare();
4028 spin_lock_irqsave(&n->list_lock, flags);
4030 if (free_debug_processing(s, slab, head, tail, &cnt, addr, handle)) {
4031 void *prior = slab->freelist;
4033 /* Perform the actual freeing while we still hold the locks */
4035 set_freepointer(s, tail, prior);
4036 slab->freelist = head;
4039 * If the slab is empty, and node's partial list is full,
4040 * it should be discarded anyway no matter it's on full or
4043 if (slab->inuse == 0 && n->nr_partial >= s->min_partial)
4047 /* was on full list */
4048 remove_full(s, n, slab);
4050 add_partial(n, slab, DEACTIVATE_TO_TAIL);
4051 stat(s, FREE_ADD_PARTIAL);
4053 } else if (slab_free) {
4054 remove_partial(n, slab);
4055 stat(s, FREE_REMOVE_PARTIAL);
4061 * Update the counters while still holding n->list_lock to
4062 * prevent spurious validation warnings
4064 dec_slabs_node(s, slab_nid(slab_free), slab_free->objects);
4067 spin_unlock_irqrestore(&n->list_lock, flags);
4071 free_slab(s, slab_free);
4076 * Slow path handling. This may still be called frequently since objects
4077 * have a longer lifetime than the cpu slabs in most processing loads.
4079 * So we still attempt to reduce cache line usage. Just take the slab
4080 * lock and free the item. If there is no additional partial slab
4081 * handling required then we can return immediately.
4083 static void __slab_free(struct kmem_cache *s, struct slab *slab,
4084 void *head, void *tail, int cnt,
4091 unsigned long counters;
4092 struct kmem_cache_node *n = NULL;
4093 unsigned long flags;
4094 bool on_node_partial;
4096 stat(s, FREE_SLOWPATH);
4098 if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
4099 free_to_partial_list(s, slab, head, tail, cnt, addr);
4105 spin_unlock_irqrestore(&n->list_lock, flags);
4108 prior = slab->freelist;
4109 counters = slab->counters;
4110 set_freepointer(s, tail, prior);
4111 new.counters = counters;
4112 was_frozen = new.frozen;
4114 if ((!new.inuse || !prior) && !was_frozen) {
4115 /* Needs to be taken off a list */
4116 if (!kmem_cache_has_cpu_partial(s) || prior) {
4118 n = get_node(s, slab_nid(slab));
4120 * Speculatively acquire the list_lock.
4121 * If the cmpxchg does not succeed then we may
4122 * drop the list_lock without any processing.
4124 * Otherwise the list_lock will synchronize with
4125 * other processors updating the list of slabs.
4127 spin_lock_irqsave(&n->list_lock, flags);
4129 on_node_partial = slab_test_node_partial(slab);
4133 } while (!slab_update_freelist(s, slab,
4140 if (likely(was_frozen)) {
4142 * The list lock was not taken therefore no list
4143 * activity can be necessary.
4145 stat(s, FREE_FROZEN);
4146 } else if (kmem_cache_has_cpu_partial(s) && !prior) {
4148 * If we started with a full slab then put it onto the
4149 * per cpu partial list.
4151 put_cpu_partial(s, slab, 1);
4152 stat(s, CPU_PARTIAL_FREE);
4159 * This slab was partially empty but not on the per-node partial list,
4160 * in which case we shouldn't manipulate its list, just return.
4162 if (prior && !on_node_partial) {
4163 spin_unlock_irqrestore(&n->list_lock, flags);
4167 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
4171 * Objects left in the slab. If it was not on the partial list before
4174 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
4175 add_partial(n, slab, DEACTIVATE_TO_TAIL);
4176 stat(s, FREE_ADD_PARTIAL);
4178 spin_unlock_irqrestore(&n->list_lock, flags);
4184 * Slab on the partial list.
4186 remove_partial(n, slab);
4187 stat(s, FREE_REMOVE_PARTIAL);
4190 spin_unlock_irqrestore(&n->list_lock, flags);
4192 discard_slab(s, slab);
4195 #ifndef CONFIG_SLUB_TINY
4197 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
4198 * can perform fastpath freeing without additional function calls.
4200 * The fastpath is only possible if we are freeing to the current cpu slab
4201 * of this processor. This typically the case if we have just allocated
4204 * If fastpath is not possible then fall back to __slab_free where we deal
4205 * with all sorts of special processing.
4207 * Bulk free of a freelist with several objects (all pointing to the
4208 * same slab) possible by specifying head and tail ptr, plus objects
4209 * count (cnt). Bulk free indicated by tail pointer being set.
4211 static __always_inline void do_slab_free(struct kmem_cache *s,
4212 struct slab *slab, void *head, void *tail,
4213 int cnt, unsigned long addr)
4215 struct kmem_cache_cpu *c;
4221 * Determine the currently cpus per cpu slab.
4222 * The cpu may change afterward. However that does not matter since
4223 * data is retrieved via this pointer. If we are on the same cpu
4224 * during the cmpxchg then the free will succeed.
4226 c = raw_cpu_ptr(s->cpu_slab);
4227 tid = READ_ONCE(c->tid);
4229 /* Same with comment on barrier() in slab_alloc_node() */
4232 if (unlikely(slab != c->slab)) {
4233 __slab_free(s, slab, head, tail, cnt, addr);
4237 if (USE_LOCKLESS_FAST_PATH()) {
4238 freelist = READ_ONCE(c->freelist);
4240 set_freepointer(s, tail, freelist);
4242 if (unlikely(!__update_cpu_freelist_fast(s, freelist, head, tid))) {
4243 note_cmpxchg_failure("slab_free", s, tid);
4247 /* Update the free list under the local lock */
4248 local_lock(&s->cpu_slab->lock);
4249 c = this_cpu_ptr(s->cpu_slab);
4250 if (unlikely(slab != c->slab)) {
4251 local_unlock(&s->cpu_slab->lock);
4255 freelist = c->freelist;
4257 set_freepointer(s, tail, freelist);
4259 c->tid = next_tid(tid);
4261 local_unlock(&s->cpu_slab->lock);
4263 stat_add(s, FREE_FASTPATH, cnt);
4265 #else /* CONFIG_SLUB_TINY */
4266 static void do_slab_free(struct kmem_cache *s,
4267 struct slab *slab, void *head, void *tail,
4268 int cnt, unsigned long addr)
4270 __slab_free(s, slab, head, tail, cnt, addr);
4272 #endif /* CONFIG_SLUB_TINY */
4274 static __fastpath_inline
4275 void slab_free(struct kmem_cache *s, struct slab *slab, void *object,
4278 memcg_slab_free_hook(s, slab, &object, 1);
4280 if (likely(slab_free_hook(s, object, slab_want_init_on_free(s))))
4281 do_slab_free(s, slab, object, object, 1, addr);
4284 static __fastpath_inline
4285 void slab_free_bulk(struct kmem_cache *s, struct slab *slab, void *head,
4286 void *tail, void **p, int cnt, unsigned long addr)
4288 memcg_slab_free_hook(s, slab, p, cnt);
4290 * With KASAN enabled slab_free_freelist_hook modifies the freelist
4291 * to remove objects, whose reuse must be delayed.
4293 if (likely(slab_free_freelist_hook(s, &head, &tail, &cnt)))
4294 do_slab_free(s, slab, head, tail, cnt, addr);
4297 #ifdef CONFIG_KASAN_GENERIC
4298 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
4300 do_slab_free(cache, virt_to_slab(x), x, x, 1, addr);
4304 static inline struct kmem_cache *virt_to_cache(const void *obj)
4308 slab = virt_to_slab(obj);
4309 if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n", __func__))
4311 return slab->slab_cache;
4314 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
4316 struct kmem_cache *cachep;
4318 if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
4319 !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
4322 cachep = virt_to_cache(x);
4323 if (WARN(cachep && cachep != s,
4324 "%s: Wrong slab cache. %s but object is from %s\n",
4325 __func__, s->name, cachep->name))
4326 print_tracking(cachep, x);
4331 * kmem_cache_free - Deallocate an object
4332 * @s: The cache the allocation was from.
4333 * @x: The previously allocated object.
4335 * Free an object which was previously allocated from this
4338 void kmem_cache_free(struct kmem_cache *s, void *x)
4340 s = cache_from_obj(s, x);
4343 trace_kmem_cache_free(_RET_IP_, x, s);
4344 slab_free(s, virt_to_slab(x), x, _RET_IP_);
4346 EXPORT_SYMBOL(kmem_cache_free);
4348 static void free_large_kmalloc(struct folio *folio, void *object)
4350 unsigned int order = folio_order(folio);
4352 if (WARN_ON_ONCE(order == 0))
4353 pr_warn_once("object pointer: 0x%p\n", object);
4355 kmemleak_free(object);
4356 kasan_kfree_large(object);
4357 kmsan_kfree_large(object);
4359 lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
4360 -(PAGE_SIZE << order));
4365 * kfree - free previously allocated memory
4366 * @object: pointer returned by kmalloc() or kmem_cache_alloc()
4368 * If @object is NULL, no operation is performed.
4370 void kfree(const void *object)
4372 struct folio *folio;
4374 struct kmem_cache *s;
4375 void *x = (void *)object;
4377 trace_kfree(_RET_IP_, object);
4379 if (unlikely(ZERO_OR_NULL_PTR(object)))
4382 folio = virt_to_folio(object);
4383 if (unlikely(!folio_test_slab(folio))) {
4384 free_large_kmalloc(folio, (void *)object);
4388 slab = folio_slab(folio);
4389 s = slab->slab_cache;
4390 slab_free(s, slab, x, _RET_IP_);
4392 EXPORT_SYMBOL(kfree);
4394 struct detached_freelist {
4399 struct kmem_cache *s;
4403 * This function progressively scans the array with free objects (with
4404 * a limited look ahead) and extract objects belonging to the same
4405 * slab. It builds a detached freelist directly within the given
4406 * slab/objects. This can happen without any need for
4407 * synchronization, because the objects are owned by running process.
4408 * The freelist is build up as a single linked list in the objects.
4409 * The idea is, that this detached freelist can then be bulk
4410 * transferred to the real freelist(s), but only requiring a single
4411 * synchronization primitive. Look ahead in the array is limited due
4412 * to performance reasons.
4415 int build_detached_freelist(struct kmem_cache *s, size_t size,
4416 void **p, struct detached_freelist *df)
4420 struct folio *folio;
4424 folio = virt_to_folio(object);
4426 /* Handle kalloc'ed objects */
4427 if (unlikely(!folio_test_slab(folio))) {
4428 free_large_kmalloc(folio, object);
4432 /* Derive kmem_cache from object */
4433 df->slab = folio_slab(folio);
4434 df->s = df->slab->slab_cache;
4436 df->slab = folio_slab(folio);
4437 df->s = cache_from_obj(s, object); /* Support for memcg */
4440 /* Start new detached freelist */
4442 df->freelist = object;
4445 if (is_kfence_address(object))
4448 set_freepointer(df->s, object, NULL);
4453 /* df->slab is always set at this point */
4454 if (df->slab == virt_to_slab(object)) {
4455 /* Opportunity build freelist */
4456 set_freepointer(df->s, object, df->freelist);
4457 df->freelist = object;
4461 swap(p[size], p[same]);
4465 /* Limit look ahead search */
4474 * Internal bulk free of objects that were not initialised by the post alloc
4475 * hooks and thus should not be processed by the free hooks
4477 static void __kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
4483 struct detached_freelist df;
4485 size = build_detached_freelist(s, size, p, &df);
4489 do_slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt,
4491 } while (likely(size));
4494 /* Note that interrupts must be enabled when calling this function. */
4495 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
4501 struct detached_freelist df;
4503 size = build_detached_freelist(s, size, p, &df);
4507 slab_free_bulk(df.s, df.slab, df.freelist, df.tail, &p[size],
4509 } while (likely(size));
4511 EXPORT_SYMBOL(kmem_cache_free_bulk);
4513 #ifndef CONFIG_SLUB_TINY
4515 int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
4518 struct kmem_cache_cpu *c;
4519 unsigned long irqflags;
4523 * Drain objects in the per cpu slab, while disabling local
4524 * IRQs, which protects against PREEMPT and interrupts
4525 * handlers invoking normal fastpath.
4527 c = slub_get_cpu_ptr(s->cpu_slab);
4528 local_lock_irqsave(&s->cpu_slab->lock, irqflags);
4530 for (i = 0; i < size; i++) {
4531 void *object = kfence_alloc(s, s->object_size, flags);
4533 if (unlikely(object)) {
4538 object = c->freelist;
4539 if (unlikely(!object)) {
4541 * We may have removed an object from c->freelist using
4542 * the fastpath in the previous iteration; in that case,
4543 * c->tid has not been bumped yet.
4544 * Since ___slab_alloc() may reenable interrupts while
4545 * allocating memory, we should bump c->tid now.
4547 c->tid = next_tid(c->tid);
4549 local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
4552 * Invoking slow path likely have side-effect
4553 * of re-populating per CPU c->freelist
4555 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
4556 _RET_IP_, c, s->object_size);
4557 if (unlikely(!p[i]))
4560 c = this_cpu_ptr(s->cpu_slab);
4561 maybe_wipe_obj_freeptr(s, p[i]);
4563 local_lock_irqsave(&s->cpu_slab->lock, irqflags);
4565 continue; /* goto for-loop */
4567 c->freelist = get_freepointer(s, object);
4569 maybe_wipe_obj_freeptr(s, p[i]);
4570 stat(s, ALLOC_FASTPATH);
4572 c->tid = next_tid(c->tid);
4573 local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
4574 slub_put_cpu_ptr(s->cpu_slab);
4579 slub_put_cpu_ptr(s->cpu_slab);
4580 __kmem_cache_free_bulk(s, i, p);
4584 #else /* CONFIG_SLUB_TINY */
4585 static int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
4586 size_t size, void **p)
4590 for (i = 0; i < size; i++) {
4591 void *object = kfence_alloc(s, s->object_size, flags);
4593 if (unlikely(object)) {
4598 p[i] = __slab_alloc_node(s, flags, NUMA_NO_NODE,
4599 _RET_IP_, s->object_size);
4600 if (unlikely(!p[i]))
4603 maybe_wipe_obj_freeptr(s, p[i]);
4609 __kmem_cache_free_bulk(s, i, p);
4612 #endif /* CONFIG_SLUB_TINY */
4614 /* Note that interrupts must be enabled when calling this function. */
4615 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
4619 struct obj_cgroup *objcg = NULL;
4624 /* memcg and kmem_cache debug support */
4625 s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
4629 i = __kmem_cache_alloc_bulk(s, flags, size, p);
4632 * memcg and kmem_cache debug support and memory initialization.
4633 * Done outside of the IRQ disabled fastpath loop.
4635 if (likely(i != 0)) {
4636 slab_post_alloc_hook(s, objcg, flags, size, p,
4637 slab_want_init_on_alloc(flags, s), s->object_size);
4639 memcg_slab_alloc_error_hook(s, size, objcg);
4644 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
4648 * Object placement in a slab is made very easy because we always start at
4649 * offset 0. If we tune the size of the object to the alignment then we can
4650 * get the required alignment by putting one properly sized object after
4653 * Notice that the allocation order determines the sizes of the per cpu
4654 * caches. Each processor has always one slab available for allocations.
4655 * Increasing the allocation order reduces the number of times that slabs
4656 * must be moved on and off the partial lists and is therefore a factor in
4661 * Minimum / Maximum order of slab pages. This influences locking overhead
4662 * and slab fragmentation. A higher order reduces the number of partial slabs
4663 * and increases the number of allocations possible without having to
4664 * take the list_lock.
4666 static unsigned int slub_min_order;
4667 static unsigned int slub_max_order =
4668 IS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;
4669 static unsigned int slub_min_objects;
4672 * Calculate the order of allocation given an slab object size.
4674 * The order of allocation has significant impact on performance and other
4675 * system components. Generally order 0 allocations should be preferred since
4676 * order 0 does not cause fragmentation in the page allocator. Larger objects
4677 * be problematic to put into order 0 slabs because there may be too much
4678 * unused space left. We go to a higher order if more than 1/16th of the slab
4681 * In order to reach satisfactory performance we must ensure that a minimum
4682 * number of objects is in one slab. Otherwise we may generate too much
4683 * activity on the partial lists which requires taking the list_lock. This is
4684 * less a concern for large slabs though which are rarely used.
4686 * slab_max_order specifies the order where we begin to stop considering the
4687 * number of objects in a slab as critical. If we reach slab_max_order then
4688 * we try to keep the page order as low as possible. So we accept more waste
4689 * of space in favor of a small page order.
4691 * Higher order allocations also allow the placement of more objects in a
4692 * slab and thereby reduce object handling overhead. If the user has
4693 * requested a higher minimum order then we start with that one instead of
4694 * the smallest order which will fit the object.
4696 static inline unsigned int calc_slab_order(unsigned int size,
4697 unsigned int min_order, unsigned int max_order,
4698 unsigned int fract_leftover)
4702 for (order = min_order; order <= max_order; order++) {
4704 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
4707 rem = slab_size % size;
4709 if (rem <= slab_size / fract_leftover)
4716 static inline int calculate_order(unsigned int size)
4719 unsigned int min_objects;
4720 unsigned int max_objects;
4721 unsigned int min_order;
4723 min_objects = slub_min_objects;
4726 * Some architectures will only update present cpus when
4727 * onlining them, so don't trust the number if it's just 1. But
4728 * we also don't want to use nr_cpu_ids always, as on some other
4729 * architectures, there can be many possible cpus, but never
4730 * onlined. Here we compromise between trying to avoid too high
4731 * order on systems that appear larger than they are, and too
4732 * low order on systems that appear smaller than they are.
4734 unsigned int nr_cpus = num_present_cpus();
4736 nr_cpus = nr_cpu_ids;
4737 min_objects = 4 * (fls(nr_cpus) + 1);
4739 /* min_objects can't be 0 because get_order(0) is undefined */
4740 max_objects = max(order_objects(slub_max_order, size), 1U);
4741 min_objects = min(min_objects, max_objects);
4743 min_order = max_t(unsigned int, slub_min_order,
4744 get_order(min_objects * size));
4745 if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
4746 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
4749 * Attempt to find best configuration for a slab. This works by first
4750 * attempting to generate a layout with the best possible configuration
4751 * and backing off gradually.
4753 * We start with accepting at most 1/16 waste and try to find the
4754 * smallest order from min_objects-derived/slab_min_order up to
4755 * slab_max_order that will satisfy the constraint. Note that increasing
4756 * the order can only result in same or less fractional waste, not more.
4758 * If that fails, we increase the acceptable fraction of waste and try
4759 * again. The last iteration with fraction of 1/2 would effectively
4760 * accept any waste and give us the order determined by min_objects, as
4761 * long as at least single object fits within slab_max_order.
4763 for (unsigned int fraction = 16; fraction > 1; fraction /= 2) {
4764 order = calc_slab_order(size, min_order, slub_max_order,
4766 if (order <= slub_max_order)
4771 * Doh this slab cannot be placed using slab_max_order.
4773 order = get_order(size);
4774 if (order <= MAX_PAGE_ORDER)
4780 init_kmem_cache_node(struct kmem_cache_node *n)
4783 spin_lock_init(&n->list_lock);
4784 INIT_LIST_HEAD(&n->partial);
4785 #ifdef CONFIG_SLUB_DEBUG
4786 atomic_long_set(&n->nr_slabs, 0);
4787 atomic_long_set(&n->total_objects, 0);
4788 INIT_LIST_HEAD(&n->full);
4792 #ifndef CONFIG_SLUB_TINY
4793 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4795 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
4796 NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
4797 sizeof(struct kmem_cache_cpu));
4800 * Must align to double word boundary for the double cmpxchg
4801 * instructions to work; see __pcpu_double_call_return_bool().
4803 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
4804 2 * sizeof(void *));
4809 init_kmem_cache_cpus(s);
4814 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4818 #endif /* CONFIG_SLUB_TINY */
4820 static struct kmem_cache *kmem_cache_node;
4823 * No kmalloc_node yet so do it by hand. We know that this is the first
4824 * slab on the node for this slabcache. There are no concurrent accesses
4827 * Note that this function only works on the kmem_cache_node
4828 * when allocating for the kmem_cache_node. This is used for bootstrapping
4829 * memory on a fresh node that has no slab structures yet.
4831 static void early_kmem_cache_node_alloc(int node)
4834 struct kmem_cache_node *n;
4836 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
4838 slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
4841 if (slab_nid(slab) != node) {
4842 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
4843 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
4848 #ifdef CONFIG_SLUB_DEBUG
4849 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
4850 init_tracking(kmem_cache_node, n);
4852 n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
4853 slab->freelist = get_freepointer(kmem_cache_node, n);
4855 kmem_cache_node->node[node] = n;
4856 init_kmem_cache_node(n);
4857 inc_slabs_node(kmem_cache_node, node, slab->objects);
4860 * No locks need to be taken here as it has just been
4861 * initialized and there is no concurrent access.
4863 __add_partial(n, slab, DEACTIVATE_TO_HEAD);
4866 static void free_kmem_cache_nodes(struct kmem_cache *s)
4869 struct kmem_cache_node *n;
4871 for_each_kmem_cache_node(s, node, n) {
4872 s->node[node] = NULL;
4873 kmem_cache_free(kmem_cache_node, n);
4877 void __kmem_cache_release(struct kmem_cache *s)
4879 cache_random_seq_destroy(s);
4880 #ifndef CONFIG_SLUB_TINY
4881 free_percpu(s->cpu_slab);
4883 free_kmem_cache_nodes(s);
4886 static int init_kmem_cache_nodes(struct kmem_cache *s)
4890 for_each_node_mask(node, slab_nodes) {
4891 struct kmem_cache_node *n;
4893 if (slab_state == DOWN) {
4894 early_kmem_cache_node_alloc(node);
4897 n = kmem_cache_alloc_node(kmem_cache_node,
4901 free_kmem_cache_nodes(s);
4905 init_kmem_cache_node(n);
4911 static void set_cpu_partial(struct kmem_cache *s)
4913 #ifdef CONFIG_SLUB_CPU_PARTIAL
4914 unsigned int nr_objects;
4917 * cpu_partial determined the maximum number of objects kept in the
4918 * per cpu partial lists of a processor.
4920 * Per cpu partial lists mainly contain slabs that just have one
4921 * object freed. If they are used for allocation then they can be
4922 * filled up again with minimal effort. The slab will never hit the
4923 * per node partial lists and therefore no locking will be required.
4925 * For backwards compatibility reasons, this is determined as number
4926 * of objects, even though we now limit maximum number of pages, see
4927 * slub_set_cpu_partial()
4929 if (!kmem_cache_has_cpu_partial(s))
4931 else if (s->size >= PAGE_SIZE)
4933 else if (s->size >= 1024)
4935 else if (s->size >= 256)
4940 slub_set_cpu_partial(s, nr_objects);
4945 * calculate_sizes() determines the order and the distribution of data within
4948 static int calculate_sizes(struct kmem_cache *s)
4950 slab_flags_t flags = s->flags;
4951 unsigned int size = s->object_size;
4955 * Round up object size to the next word boundary. We can only
4956 * place the free pointer at word boundaries and this determines
4957 * the possible location of the free pointer.
4959 size = ALIGN(size, sizeof(void *));
4961 #ifdef CONFIG_SLUB_DEBUG
4963 * Determine if we can poison the object itself. If the user of
4964 * the slab may touch the object after free or before allocation
4965 * then we should never poison the object itself.
4967 if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
4969 s->flags |= __OBJECT_POISON;
4971 s->flags &= ~__OBJECT_POISON;
4975 * If we are Redzoning then check if there is some space between the
4976 * end of the object and the free pointer. If not then add an
4977 * additional word to have some bytes to store Redzone information.
4979 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
4980 size += sizeof(void *);
4984 * With that we have determined the number of bytes in actual use
4985 * by the object and redzoning.
4989 if (slub_debug_orig_size(s) ||
4990 (flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
4991 ((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) ||
4994 * Relocate free pointer after the object if it is not
4995 * permitted to overwrite the first word of the object on
4998 * This is the case if we do RCU, have a constructor or
4999 * destructor, are poisoning the objects, or are
5000 * redzoning an object smaller than sizeof(void *).
5002 * The assumption that s->offset >= s->inuse means free
5003 * pointer is outside of the object is used in the
5004 * freeptr_outside_object() function. If that is no
5005 * longer true, the function needs to be modified.
5008 size += sizeof(void *);
5011 * Store freelist pointer near middle of object to keep
5012 * it away from the edges of the object to avoid small
5013 * sized over/underflows from neighboring allocations.
5015 s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
5018 #ifdef CONFIG_SLUB_DEBUG
5019 if (flags & SLAB_STORE_USER) {
5021 * Need to store information about allocs and frees after
5024 size += 2 * sizeof(struct track);
5026 /* Save the original kmalloc request size */
5027 if (flags & SLAB_KMALLOC)
5028 size += sizeof(unsigned int);
5032 kasan_cache_create(s, &size, &s->flags);
5033 #ifdef CONFIG_SLUB_DEBUG
5034 if (flags & SLAB_RED_ZONE) {
5036 * Add some empty padding so that we can catch
5037 * overwrites from earlier objects rather than let
5038 * tracking information or the free pointer be
5039 * corrupted if a user writes before the start
5042 size += sizeof(void *);
5044 s->red_left_pad = sizeof(void *);
5045 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
5046 size += s->red_left_pad;
5051 * SLUB stores one object immediately after another beginning from
5052 * offset 0. In order to align the objects we have to simply size
5053 * each object to conform to the alignment.
5055 size = ALIGN(size, s->align);
5057 s->reciprocal_size = reciprocal_value(size);
5058 order = calculate_order(size);
5065 s->allocflags |= __GFP_COMP;
5067 if (s->flags & SLAB_CACHE_DMA)
5068 s->allocflags |= GFP_DMA;
5070 if (s->flags & SLAB_CACHE_DMA32)
5071 s->allocflags |= GFP_DMA32;
5073 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5074 s->allocflags |= __GFP_RECLAIMABLE;
5077 * Determine the number of objects per slab
5079 s->oo = oo_make(order, size);
5080 s->min = oo_make(get_order(size), size);
5082 return !!oo_objects(s->oo);
5085 static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
5087 s->flags = kmem_cache_flags(flags, s->name);
5088 #ifdef CONFIG_SLAB_FREELIST_HARDENED
5089 s->random = get_random_long();
5092 if (!calculate_sizes(s))
5094 if (disable_higher_order_debug) {
5096 * Disable debugging flags that store metadata if the min slab
5099 if (get_order(s->size) > get_order(s->object_size)) {
5100 s->flags &= ~DEBUG_METADATA_FLAGS;
5102 if (!calculate_sizes(s))
5107 #ifdef system_has_freelist_aba
5108 if (system_has_freelist_aba() && !(s->flags & SLAB_NO_CMPXCHG)) {
5109 /* Enable fast mode */
5110 s->flags |= __CMPXCHG_DOUBLE;
5115 * The larger the object size is, the more slabs we want on the partial
5116 * list to avoid pounding the page allocator excessively.
5118 s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
5119 s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
5124 s->remote_node_defrag_ratio = 1000;
5127 /* Initialize the pre-computed randomized freelist if slab is up */
5128 if (slab_state >= UP) {
5129 if (init_cache_random_seq(s))
5133 if (!init_kmem_cache_nodes(s))
5136 if (alloc_kmem_cache_cpus(s))
5140 __kmem_cache_release(s);
5144 static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
5147 #ifdef CONFIG_SLUB_DEBUG
5148 void *addr = slab_address(slab);
5151 slab_err(s, slab, text, s->name);
5153 spin_lock(&object_map_lock);
5154 __fill_map(object_map, s, slab);
5156 for_each_object(p, s, addr, slab->objects) {
5158 if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
5159 pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
5160 print_tracking(s, p);
5163 spin_unlock(&object_map_lock);
5168 * Attempt to free all partial slabs on a node.
5169 * This is called from __kmem_cache_shutdown(). We must take list_lock
5170 * because sysfs file might still access partial list after the shutdowning.
5172 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
5175 struct slab *slab, *h;
5177 BUG_ON(irqs_disabled());
5178 spin_lock_irq(&n->list_lock);
5179 list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
5181 remove_partial(n, slab);
5182 list_add(&slab->slab_list, &discard);
5184 list_slab_objects(s, slab,
5185 "Objects remaining in %s on __kmem_cache_shutdown()");
5188 spin_unlock_irq(&n->list_lock);
5190 list_for_each_entry_safe(slab, h, &discard, slab_list)
5191 discard_slab(s, slab);
5194 bool __kmem_cache_empty(struct kmem_cache *s)
5197 struct kmem_cache_node *n;
5199 for_each_kmem_cache_node(s, node, n)
5200 if (n->nr_partial || node_nr_slabs(n))
5206 * Release all resources used by a slab cache.
5208 int __kmem_cache_shutdown(struct kmem_cache *s)
5211 struct kmem_cache_node *n;
5213 flush_all_cpus_locked(s);
5214 /* Attempt to free all objects */
5215 for_each_kmem_cache_node(s, node, n) {
5217 if (n->nr_partial || node_nr_slabs(n))
5223 #ifdef CONFIG_PRINTK
5224 void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
5227 int __maybe_unused i;
5231 struct kmem_cache *s = slab->slab_cache;
5232 struct track __maybe_unused *trackp;
5234 kpp->kp_ptr = object;
5235 kpp->kp_slab = slab;
5236 kpp->kp_slab_cache = s;
5237 base = slab_address(slab);
5238 objp0 = kasan_reset_tag(object);
5239 #ifdef CONFIG_SLUB_DEBUG
5240 objp = restore_red_left(s, objp0);
5244 objnr = obj_to_index(s, slab, objp);
5245 kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
5246 objp = base + s->size * objnr;
5247 kpp->kp_objp = objp;
5248 if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
5249 || (objp - base) % s->size) ||
5250 !(s->flags & SLAB_STORE_USER))
5252 #ifdef CONFIG_SLUB_DEBUG
5253 objp = fixup_red_left(s, objp);
5254 trackp = get_track(s, objp, TRACK_ALLOC);
5255 kpp->kp_ret = (void *)trackp->addr;
5256 #ifdef CONFIG_STACKDEPOT
5258 depot_stack_handle_t handle;
5259 unsigned long *entries;
5260 unsigned int nr_entries;
5262 handle = READ_ONCE(trackp->handle);
5264 nr_entries = stack_depot_fetch(handle, &entries);
5265 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
5266 kpp->kp_stack[i] = (void *)entries[i];
5269 trackp = get_track(s, objp, TRACK_FREE);
5270 handle = READ_ONCE(trackp->handle);
5272 nr_entries = stack_depot_fetch(handle, &entries);
5273 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
5274 kpp->kp_free_stack[i] = (void *)entries[i];
5282 /********************************************************************
5284 *******************************************************************/
5286 static int __init setup_slub_min_order(char *str)
5288 get_option(&str, (int *)&slub_min_order);
5290 if (slub_min_order > slub_max_order)
5291 slub_max_order = slub_min_order;
5296 __setup("slab_min_order=", setup_slub_min_order);
5297 __setup_param("slub_min_order=", slub_min_order, setup_slub_min_order, 0);
5300 static int __init setup_slub_max_order(char *str)
5302 get_option(&str, (int *)&slub_max_order);
5303 slub_max_order = min_t(unsigned int, slub_max_order, MAX_PAGE_ORDER);
5305 if (slub_min_order > slub_max_order)
5306 slub_min_order = slub_max_order;
5311 __setup("slab_max_order=", setup_slub_max_order);
5312 __setup_param("slub_max_order=", slub_max_order, setup_slub_max_order, 0);
5314 static int __init setup_slub_min_objects(char *str)
5316 get_option(&str, (int *)&slub_min_objects);
5321 __setup("slab_min_objects=", setup_slub_min_objects);
5322 __setup_param("slub_min_objects=", slub_min_objects, setup_slub_min_objects, 0);
5324 #ifdef CONFIG_HARDENED_USERCOPY
5326 * Rejects incorrectly sized objects and objects that are to be copied
5327 * to/from userspace but do not fall entirely within the containing slab
5328 * cache's usercopy region.
5330 * Returns NULL if check passes, otherwise const char * to name of cache
5331 * to indicate an error.
5333 void __check_heap_object(const void *ptr, unsigned long n,
5334 const struct slab *slab, bool to_user)
5336 struct kmem_cache *s;
5337 unsigned int offset;
5338 bool is_kfence = is_kfence_address(ptr);
5340 ptr = kasan_reset_tag(ptr);
5342 /* Find object and usable object size. */
5343 s = slab->slab_cache;
5345 /* Reject impossible pointers. */
5346 if (ptr < slab_address(slab))
5347 usercopy_abort("SLUB object not in SLUB page?!", NULL,
5350 /* Find offset within object. */
5352 offset = ptr - kfence_object_start(ptr);
5354 offset = (ptr - slab_address(slab)) % s->size;
5356 /* Adjust for redzone and reject if within the redzone. */
5357 if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
5358 if (offset < s->red_left_pad)
5359 usercopy_abort("SLUB object in left red zone",
5360 s->name, to_user, offset, n);
5361 offset -= s->red_left_pad;
5364 /* Allow address range falling entirely within usercopy region. */
5365 if (offset >= s->useroffset &&
5366 offset - s->useroffset <= s->usersize &&
5367 n <= s->useroffset - offset + s->usersize)
5370 usercopy_abort("SLUB object", s->name, to_user, offset, n);
5372 #endif /* CONFIG_HARDENED_USERCOPY */
5374 #define SHRINK_PROMOTE_MAX 32
5377 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
5378 * up most to the head of the partial lists. New allocations will then
5379 * fill those up and thus they can be removed from the partial lists.
5381 * The slabs with the least items are placed last. This results in them
5382 * being allocated from last increasing the chance that the last objects
5383 * are freed in them.
5385 static int __kmem_cache_do_shrink(struct kmem_cache *s)
5389 struct kmem_cache_node *n;
5392 struct list_head discard;
5393 struct list_head promote[SHRINK_PROMOTE_MAX];
5394 unsigned long flags;
5397 for_each_kmem_cache_node(s, node, n) {
5398 INIT_LIST_HEAD(&discard);
5399 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
5400 INIT_LIST_HEAD(promote + i);
5402 spin_lock_irqsave(&n->list_lock, flags);
5405 * Build lists of slabs to discard or promote.
5407 * Note that concurrent frees may occur while we hold the
5408 * list_lock. slab->inuse here is the upper limit.
5410 list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
5411 int free = slab->objects - slab->inuse;
5413 /* Do not reread slab->inuse */
5416 /* We do not keep full slabs on the list */
5419 if (free == slab->objects) {
5420 list_move(&slab->slab_list, &discard);
5421 slab_clear_node_partial(slab);
5423 dec_slabs_node(s, node, slab->objects);
5424 } else if (free <= SHRINK_PROMOTE_MAX)
5425 list_move(&slab->slab_list, promote + free - 1);
5429 * Promote the slabs filled up most to the head of the
5432 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
5433 list_splice(promote + i, &n->partial);
5435 spin_unlock_irqrestore(&n->list_lock, flags);
5437 /* Release empty slabs */
5438 list_for_each_entry_safe(slab, t, &discard, slab_list)
5441 if (node_nr_slabs(n))
5448 int __kmem_cache_shrink(struct kmem_cache *s)
5451 return __kmem_cache_do_shrink(s);
5454 static int slab_mem_going_offline_callback(void *arg)
5456 struct kmem_cache *s;
5458 mutex_lock(&slab_mutex);
5459 list_for_each_entry(s, &slab_caches, list) {
5460 flush_all_cpus_locked(s);
5461 __kmem_cache_do_shrink(s);
5463 mutex_unlock(&slab_mutex);
5468 static void slab_mem_offline_callback(void *arg)
5470 struct memory_notify *marg = arg;
5473 offline_node = marg->status_change_nid_normal;
5476 * If the node still has available memory. we need kmem_cache_node
5479 if (offline_node < 0)
5482 mutex_lock(&slab_mutex);
5483 node_clear(offline_node, slab_nodes);
5485 * We no longer free kmem_cache_node structures here, as it would be
5486 * racy with all get_node() users, and infeasible to protect them with
5489 mutex_unlock(&slab_mutex);
5492 static int slab_mem_going_online_callback(void *arg)
5494 struct kmem_cache_node *n;
5495 struct kmem_cache *s;
5496 struct memory_notify *marg = arg;
5497 int nid = marg->status_change_nid_normal;
5501 * If the node's memory is already available, then kmem_cache_node is
5502 * already created. Nothing to do.
5508 * We are bringing a node online. No memory is available yet. We must
5509 * allocate a kmem_cache_node structure in order to bring the node
5512 mutex_lock(&slab_mutex);
5513 list_for_each_entry(s, &slab_caches, list) {
5515 * The structure may already exist if the node was previously
5516 * onlined and offlined.
5518 if (get_node(s, nid))
5521 * XXX: kmem_cache_alloc_node will fallback to other nodes
5522 * since memory is not yet available from the node that
5525 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
5530 init_kmem_cache_node(n);
5534 * Any cache created after this point will also have kmem_cache_node
5535 * initialized for the new node.
5537 node_set(nid, slab_nodes);
5539 mutex_unlock(&slab_mutex);
5543 static int slab_memory_callback(struct notifier_block *self,
5544 unsigned long action, void *arg)
5549 case MEM_GOING_ONLINE:
5550 ret = slab_mem_going_online_callback(arg);
5552 case MEM_GOING_OFFLINE:
5553 ret = slab_mem_going_offline_callback(arg);
5556 case MEM_CANCEL_ONLINE:
5557 slab_mem_offline_callback(arg);
5560 case MEM_CANCEL_OFFLINE:
5564 ret = notifier_from_errno(ret);
5570 /********************************************************************
5571 * Basic setup of slabs
5572 *******************************************************************/
5575 * Used for early kmem_cache structures that were allocated using
5576 * the page allocator. Allocate them properly then fix up the pointers
5577 * that may be pointing to the wrong kmem_cache structure.
5580 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
5583 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
5584 struct kmem_cache_node *n;
5586 memcpy(s, static_cache, kmem_cache->object_size);
5589 * This runs very early, and only the boot processor is supposed to be
5590 * up. Even if it weren't true, IRQs are not up so we couldn't fire
5593 __flush_cpu_slab(s, smp_processor_id());
5594 for_each_kmem_cache_node(s, node, n) {
5597 list_for_each_entry(p, &n->partial, slab_list)
5600 #ifdef CONFIG_SLUB_DEBUG
5601 list_for_each_entry(p, &n->full, slab_list)
5605 list_add(&s->list, &slab_caches);
5609 void __init kmem_cache_init(void)
5611 static __initdata struct kmem_cache boot_kmem_cache,
5612 boot_kmem_cache_node;
5615 if (debug_guardpage_minorder())
5618 /* Print slub debugging pointers without hashing */
5619 if (__slub_debug_enabled())
5620 no_hash_pointers_enable(NULL);
5622 kmem_cache_node = &boot_kmem_cache_node;
5623 kmem_cache = &boot_kmem_cache;
5626 * Initialize the nodemask for which we will allocate per node
5627 * structures. Here we don't need taking slab_mutex yet.
5629 for_each_node_state(node, N_NORMAL_MEMORY)
5630 node_set(node, slab_nodes);
5632 create_boot_cache(kmem_cache_node, "kmem_cache_node",
5633 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
5635 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
5637 /* Able to allocate the per node structures */
5638 slab_state = PARTIAL;
5640 create_boot_cache(kmem_cache, "kmem_cache",
5641 offsetof(struct kmem_cache, node) +
5642 nr_node_ids * sizeof(struct kmem_cache_node *),
5643 SLAB_HWCACHE_ALIGN, 0, 0);
5645 kmem_cache = bootstrap(&boot_kmem_cache);
5646 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
5648 /* Now we can use the kmem_cache to allocate kmalloc slabs */
5649 setup_kmalloc_cache_index_table();
5650 create_kmalloc_caches();
5652 /* Setup random freelists for each cache */
5653 init_freelist_randomization();
5655 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
5658 pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
5660 slub_min_order, slub_max_order, slub_min_objects,
5661 nr_cpu_ids, nr_node_ids);
5664 void __init kmem_cache_init_late(void)
5666 #ifndef CONFIG_SLUB_TINY
5667 flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
5673 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
5674 slab_flags_t flags, void (*ctor)(void *))
5676 struct kmem_cache *s;
5678 s = find_mergeable(size, align, flags, name, ctor);
5680 if (sysfs_slab_alias(s, name))
5686 * Adjust the object sizes so that we clear
5687 * the complete object on kzalloc.
5689 s->object_size = max(s->object_size, size);
5690 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
5696 int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
5700 err = kmem_cache_open(s, flags);
5704 /* Mutex is not taken during early boot */
5705 if (slab_state <= UP)
5708 err = sysfs_slab_add(s);
5710 __kmem_cache_release(s);
5714 if (s->flags & SLAB_STORE_USER)
5715 debugfs_slab_add(s);
5720 #ifdef SLAB_SUPPORTS_SYSFS
5721 static int count_inuse(struct slab *slab)
5726 static int count_total(struct slab *slab)
5728 return slab->objects;
5732 #ifdef CONFIG_SLUB_DEBUG
5733 static void validate_slab(struct kmem_cache *s, struct slab *slab,
5734 unsigned long *obj_map)
5737 void *addr = slab_address(slab);
5739 if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
5742 /* Now we know that a valid freelist exists */
5743 __fill_map(obj_map, s, slab);
5744 for_each_object(p, s, addr, slab->objects) {
5745 u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
5746 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
5748 if (!check_object(s, slab, p, val))
5753 static int validate_slab_node(struct kmem_cache *s,
5754 struct kmem_cache_node *n, unsigned long *obj_map)
5756 unsigned long count = 0;
5758 unsigned long flags;
5760 spin_lock_irqsave(&n->list_lock, flags);
5762 list_for_each_entry(slab, &n->partial, slab_list) {
5763 validate_slab(s, slab, obj_map);
5766 if (count != n->nr_partial) {
5767 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
5768 s->name, count, n->nr_partial);
5769 slab_add_kunit_errors();
5772 if (!(s->flags & SLAB_STORE_USER))
5775 list_for_each_entry(slab, &n->full, slab_list) {
5776 validate_slab(s, slab, obj_map);
5779 if (count != node_nr_slabs(n)) {
5780 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
5781 s->name, count, node_nr_slabs(n));
5782 slab_add_kunit_errors();
5786 spin_unlock_irqrestore(&n->list_lock, flags);
5790 long validate_slab_cache(struct kmem_cache *s)
5793 unsigned long count = 0;
5794 struct kmem_cache_node *n;
5795 unsigned long *obj_map;
5797 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
5802 for_each_kmem_cache_node(s, node, n)
5803 count += validate_slab_node(s, n, obj_map);
5805 bitmap_free(obj_map);
5809 EXPORT_SYMBOL(validate_slab_cache);
5811 #ifdef CONFIG_DEBUG_FS
5813 * Generate lists of code addresses where slabcache objects are allocated
5818 depot_stack_handle_t handle;
5819 unsigned long count;
5821 unsigned long waste;
5827 DECLARE_BITMAP(cpus, NR_CPUS);
5833 unsigned long count;
5834 struct location *loc;
5838 static struct dentry *slab_debugfs_root;
5840 static void free_loc_track(struct loc_track *t)
5843 free_pages((unsigned long)t->loc,
5844 get_order(sizeof(struct location) * t->max));
5847 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
5852 order = get_order(sizeof(struct location) * max);
5854 l = (void *)__get_free_pages(flags, order);
5859 memcpy(l, t->loc, sizeof(struct location) * t->count);
5867 static int add_location(struct loc_track *t, struct kmem_cache *s,
5868 const struct track *track,
5869 unsigned int orig_size)
5871 long start, end, pos;
5873 unsigned long caddr, chandle, cwaste;
5874 unsigned long age = jiffies - track->when;
5875 depot_stack_handle_t handle = 0;
5876 unsigned int waste = s->object_size - orig_size;
5878 #ifdef CONFIG_STACKDEPOT
5879 handle = READ_ONCE(track->handle);
5885 pos = start + (end - start + 1) / 2;
5888 * There is nothing at "end". If we end up there
5889 * we need to add something to before end.
5896 chandle = l->handle;
5898 if ((track->addr == caddr) && (handle == chandle) &&
5899 (waste == cwaste)) {
5904 if (age < l->min_time)
5906 if (age > l->max_time)
5909 if (track->pid < l->min_pid)
5910 l->min_pid = track->pid;
5911 if (track->pid > l->max_pid)
5912 l->max_pid = track->pid;
5914 cpumask_set_cpu(track->cpu,
5915 to_cpumask(l->cpus));
5917 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5921 if (track->addr < caddr)
5923 else if (track->addr == caddr && handle < chandle)
5925 else if (track->addr == caddr && handle == chandle &&
5933 * Not found. Insert new tracking element.
5935 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
5941 (t->count - pos) * sizeof(struct location));
5944 l->addr = track->addr;
5948 l->min_pid = track->pid;
5949 l->max_pid = track->pid;
5952 cpumask_clear(to_cpumask(l->cpus));
5953 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
5954 nodes_clear(l->nodes);
5955 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5959 static void process_slab(struct loc_track *t, struct kmem_cache *s,
5960 struct slab *slab, enum track_item alloc,
5961 unsigned long *obj_map)
5963 void *addr = slab_address(slab);
5964 bool is_alloc = (alloc == TRACK_ALLOC);
5967 __fill_map(obj_map, s, slab);
5969 for_each_object(p, s, addr, slab->objects)
5970 if (!test_bit(__obj_to_index(s, addr, p), obj_map))
5971 add_location(t, s, get_track(s, p, alloc),
5972 is_alloc ? get_orig_size(s, p) :
5975 #endif /* CONFIG_DEBUG_FS */
5976 #endif /* CONFIG_SLUB_DEBUG */
5978 #ifdef SLAB_SUPPORTS_SYSFS
5979 enum slab_stat_type {
5980 SL_ALL, /* All slabs */
5981 SL_PARTIAL, /* Only partially allocated slabs */
5982 SL_CPU, /* Only slabs used for cpu caches */
5983 SL_OBJECTS, /* Determine allocated objects not slabs */
5984 SL_TOTAL /* Determine object capacity not slabs */
5987 #define SO_ALL (1 << SL_ALL)
5988 #define SO_PARTIAL (1 << SL_PARTIAL)
5989 #define SO_CPU (1 << SL_CPU)
5990 #define SO_OBJECTS (1 << SL_OBJECTS)
5991 #define SO_TOTAL (1 << SL_TOTAL)
5993 static ssize_t show_slab_objects(struct kmem_cache *s,
5994 char *buf, unsigned long flags)
5996 unsigned long total = 0;
5999 unsigned long *nodes;
6002 nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
6006 if (flags & SO_CPU) {
6009 for_each_possible_cpu(cpu) {
6010 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
6015 slab = READ_ONCE(c->slab);
6019 node = slab_nid(slab);
6020 if (flags & SO_TOTAL)
6022 else if (flags & SO_OBJECTS)
6030 #ifdef CONFIG_SLUB_CPU_PARTIAL
6031 slab = slub_percpu_partial_read_once(c);
6033 node = slab_nid(slab);
6034 if (flags & SO_TOTAL)
6036 else if (flags & SO_OBJECTS)
6048 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
6049 * already held which will conflict with an existing lock order:
6051 * mem_hotplug_lock->slab_mutex->kernfs_mutex
6053 * We don't really need mem_hotplug_lock (to hold off
6054 * slab_mem_going_offline_callback) here because slab's memory hot
6055 * unplug code doesn't destroy the kmem_cache->node[] data.
6058 #ifdef CONFIG_SLUB_DEBUG
6059 if (flags & SO_ALL) {
6060 struct kmem_cache_node *n;
6062 for_each_kmem_cache_node(s, node, n) {
6064 if (flags & SO_TOTAL)
6065 x = node_nr_objs(n);
6066 else if (flags & SO_OBJECTS)
6067 x = node_nr_objs(n) - count_partial(n, count_free);
6069 x = node_nr_slabs(n);
6076 if (flags & SO_PARTIAL) {
6077 struct kmem_cache_node *n;
6079 for_each_kmem_cache_node(s, node, n) {
6080 if (flags & SO_TOTAL)
6081 x = count_partial(n, count_total);
6082 else if (flags & SO_OBJECTS)
6083 x = count_partial(n, count_inuse);
6091 len += sysfs_emit_at(buf, len, "%lu", total);
6093 for (node = 0; node < nr_node_ids; node++) {
6095 len += sysfs_emit_at(buf, len, " N%d=%lu",
6099 len += sysfs_emit_at(buf, len, "\n");
6105 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
6106 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
6108 struct slab_attribute {
6109 struct attribute attr;
6110 ssize_t (*show)(struct kmem_cache *s, char *buf);
6111 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
6114 #define SLAB_ATTR_RO(_name) \
6115 static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
6117 #define SLAB_ATTR(_name) \
6118 static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
6120 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
6122 return sysfs_emit(buf, "%u\n", s->size);
6124 SLAB_ATTR_RO(slab_size);
6126 static ssize_t align_show(struct kmem_cache *s, char *buf)
6128 return sysfs_emit(buf, "%u\n", s->align);
6130 SLAB_ATTR_RO(align);
6132 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
6134 return sysfs_emit(buf, "%u\n", s->object_size);
6136 SLAB_ATTR_RO(object_size);
6138 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
6140 return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
6142 SLAB_ATTR_RO(objs_per_slab);
6144 static ssize_t order_show(struct kmem_cache *s, char *buf)
6146 return sysfs_emit(buf, "%u\n", oo_order(s->oo));
6148 SLAB_ATTR_RO(order);
6150 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
6152 return sysfs_emit(buf, "%lu\n", s->min_partial);
6155 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
6161 err = kstrtoul(buf, 10, &min);
6165 s->min_partial = min;
6168 SLAB_ATTR(min_partial);
6170 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
6172 unsigned int nr_partial = 0;
6173 #ifdef CONFIG_SLUB_CPU_PARTIAL
6174 nr_partial = s->cpu_partial;
6177 return sysfs_emit(buf, "%u\n", nr_partial);
6180 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
6183 unsigned int objects;
6186 err = kstrtouint(buf, 10, &objects);
6189 if (objects && !kmem_cache_has_cpu_partial(s))
6192 slub_set_cpu_partial(s, objects);
6196 SLAB_ATTR(cpu_partial);
6198 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
6202 return sysfs_emit(buf, "%pS\n", s->ctor);
6206 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
6208 return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
6210 SLAB_ATTR_RO(aliases);
6212 static ssize_t partial_show(struct kmem_cache *s, char *buf)
6214 return show_slab_objects(s, buf, SO_PARTIAL);
6216 SLAB_ATTR_RO(partial);
6218 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
6220 return show_slab_objects(s, buf, SO_CPU);
6222 SLAB_ATTR_RO(cpu_slabs);
6224 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
6226 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
6228 SLAB_ATTR_RO(objects_partial);
6230 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
6234 int cpu __maybe_unused;
6237 #ifdef CONFIG_SLUB_CPU_PARTIAL
6238 for_each_online_cpu(cpu) {
6241 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
6244 slabs += slab->slabs;
6248 /* Approximate half-full slabs, see slub_set_cpu_partial() */
6249 objects = (slabs * oo_objects(s->oo)) / 2;
6250 len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
6252 #ifdef CONFIG_SLUB_CPU_PARTIAL
6253 for_each_online_cpu(cpu) {
6256 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
6258 slabs = READ_ONCE(slab->slabs);
6259 objects = (slabs * oo_objects(s->oo)) / 2;
6260 len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
6261 cpu, objects, slabs);
6265 len += sysfs_emit_at(buf, len, "\n");
6269 SLAB_ATTR_RO(slabs_cpu_partial);
6271 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
6273 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
6275 SLAB_ATTR_RO(reclaim_account);
6277 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
6279 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
6281 SLAB_ATTR_RO(hwcache_align);
6283 #ifdef CONFIG_ZONE_DMA
6284 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
6286 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
6288 SLAB_ATTR_RO(cache_dma);
6291 #ifdef CONFIG_HARDENED_USERCOPY
6292 static ssize_t usersize_show(struct kmem_cache *s, char *buf)
6294 return sysfs_emit(buf, "%u\n", s->usersize);
6296 SLAB_ATTR_RO(usersize);
6299 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
6301 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
6303 SLAB_ATTR_RO(destroy_by_rcu);
6305 #ifdef CONFIG_SLUB_DEBUG
6306 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
6308 return show_slab_objects(s, buf, SO_ALL);
6310 SLAB_ATTR_RO(slabs);
6312 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
6314 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
6316 SLAB_ATTR_RO(total_objects);
6318 static ssize_t objects_show(struct kmem_cache *s, char *buf)
6320 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
6322 SLAB_ATTR_RO(objects);
6324 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
6326 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
6328 SLAB_ATTR_RO(sanity_checks);
6330 static ssize_t trace_show(struct kmem_cache *s, char *buf)
6332 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
6334 SLAB_ATTR_RO(trace);
6336 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
6338 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
6341 SLAB_ATTR_RO(red_zone);
6343 static ssize_t poison_show(struct kmem_cache *s, char *buf)
6345 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
6348 SLAB_ATTR_RO(poison);
6350 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
6352 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
6355 SLAB_ATTR_RO(store_user);
6357 static ssize_t validate_show(struct kmem_cache *s, char *buf)
6362 static ssize_t validate_store(struct kmem_cache *s,
6363 const char *buf, size_t length)
6367 if (buf[0] == '1' && kmem_cache_debug(s)) {
6368 ret = validate_slab_cache(s);
6374 SLAB_ATTR(validate);
6376 #endif /* CONFIG_SLUB_DEBUG */
6378 #ifdef CONFIG_FAILSLAB
6379 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
6381 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
6384 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
6387 if (s->refcount > 1)
6391 WRITE_ONCE(s->flags, s->flags | SLAB_FAILSLAB);
6393 WRITE_ONCE(s->flags, s->flags & ~SLAB_FAILSLAB);
6397 SLAB_ATTR(failslab);
6400 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
6405 static ssize_t shrink_store(struct kmem_cache *s,
6406 const char *buf, size_t length)
6409 kmem_cache_shrink(s);
6417 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
6419 return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
6422 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
6423 const char *buf, size_t length)
6428 err = kstrtouint(buf, 10, &ratio);
6434 s->remote_node_defrag_ratio = ratio * 10;
6438 SLAB_ATTR(remote_node_defrag_ratio);
6441 #ifdef CONFIG_SLUB_STATS
6442 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
6444 unsigned long sum = 0;
6447 int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
6452 for_each_online_cpu(cpu) {
6453 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
6459 len += sysfs_emit_at(buf, len, "%lu", sum);
6462 for_each_online_cpu(cpu) {
6464 len += sysfs_emit_at(buf, len, " C%d=%u",
6469 len += sysfs_emit_at(buf, len, "\n");
6474 static void clear_stat(struct kmem_cache *s, enum stat_item si)
6478 for_each_online_cpu(cpu)
6479 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
6482 #define STAT_ATTR(si, text) \
6483 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
6485 return show_stat(s, buf, si); \
6487 static ssize_t text##_store(struct kmem_cache *s, \
6488 const char *buf, size_t length) \
6490 if (buf[0] != '0') \
6492 clear_stat(s, si); \
6497 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
6498 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
6499 STAT_ATTR(FREE_FASTPATH, free_fastpath);
6500 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
6501 STAT_ATTR(FREE_FROZEN, free_frozen);
6502 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
6503 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
6504 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
6505 STAT_ATTR(ALLOC_SLAB, alloc_slab);
6506 STAT_ATTR(ALLOC_REFILL, alloc_refill);
6507 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
6508 STAT_ATTR(FREE_SLAB, free_slab);
6509 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
6510 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
6511 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
6512 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
6513 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
6514 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
6515 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
6516 STAT_ATTR(ORDER_FALLBACK, order_fallback);
6517 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
6518 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
6519 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
6520 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
6521 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
6522 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
6523 #endif /* CONFIG_SLUB_STATS */
6525 #ifdef CONFIG_KFENCE
6526 static ssize_t skip_kfence_show(struct kmem_cache *s, char *buf)
6528 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_SKIP_KFENCE));
6531 static ssize_t skip_kfence_store(struct kmem_cache *s,
6532 const char *buf, size_t length)
6537 s->flags &= ~SLAB_SKIP_KFENCE;
6538 else if (buf[0] == '1')
6539 s->flags |= SLAB_SKIP_KFENCE;
6545 SLAB_ATTR(skip_kfence);
6548 static struct attribute *slab_attrs[] = {
6549 &slab_size_attr.attr,
6550 &object_size_attr.attr,
6551 &objs_per_slab_attr.attr,
6553 &min_partial_attr.attr,
6554 &cpu_partial_attr.attr,
6555 &objects_partial_attr.attr,
6557 &cpu_slabs_attr.attr,
6561 &hwcache_align_attr.attr,
6562 &reclaim_account_attr.attr,
6563 &destroy_by_rcu_attr.attr,
6565 &slabs_cpu_partial_attr.attr,
6566 #ifdef CONFIG_SLUB_DEBUG
6567 &total_objects_attr.attr,
6570 &sanity_checks_attr.attr,
6572 &red_zone_attr.attr,
6574 &store_user_attr.attr,
6575 &validate_attr.attr,
6577 #ifdef CONFIG_ZONE_DMA
6578 &cache_dma_attr.attr,
6581 &remote_node_defrag_ratio_attr.attr,
6583 #ifdef CONFIG_SLUB_STATS
6584 &alloc_fastpath_attr.attr,
6585 &alloc_slowpath_attr.attr,
6586 &free_fastpath_attr.attr,
6587 &free_slowpath_attr.attr,
6588 &free_frozen_attr.attr,
6589 &free_add_partial_attr.attr,
6590 &free_remove_partial_attr.attr,
6591 &alloc_from_partial_attr.attr,
6592 &alloc_slab_attr.attr,
6593 &alloc_refill_attr.attr,
6594 &alloc_node_mismatch_attr.attr,
6595 &free_slab_attr.attr,
6596 &cpuslab_flush_attr.attr,
6597 &deactivate_full_attr.attr,
6598 &deactivate_empty_attr.attr,
6599 &deactivate_to_head_attr.attr,
6600 &deactivate_to_tail_attr.attr,
6601 &deactivate_remote_frees_attr.attr,
6602 &deactivate_bypass_attr.attr,
6603 &order_fallback_attr.attr,
6604 &cmpxchg_double_fail_attr.attr,
6605 &cmpxchg_double_cpu_fail_attr.attr,
6606 &cpu_partial_alloc_attr.attr,
6607 &cpu_partial_free_attr.attr,
6608 &cpu_partial_node_attr.attr,
6609 &cpu_partial_drain_attr.attr,
6611 #ifdef CONFIG_FAILSLAB
6612 &failslab_attr.attr,
6614 #ifdef CONFIG_HARDENED_USERCOPY
6615 &usersize_attr.attr,
6617 #ifdef CONFIG_KFENCE
6618 &skip_kfence_attr.attr,
6624 static const struct attribute_group slab_attr_group = {
6625 .attrs = slab_attrs,
6628 static ssize_t slab_attr_show(struct kobject *kobj,
6629 struct attribute *attr,
6632 struct slab_attribute *attribute;
6633 struct kmem_cache *s;
6635 attribute = to_slab_attr(attr);
6638 if (!attribute->show)
6641 return attribute->show(s, buf);
6644 static ssize_t slab_attr_store(struct kobject *kobj,
6645 struct attribute *attr,
6646 const char *buf, size_t len)
6648 struct slab_attribute *attribute;
6649 struct kmem_cache *s;
6651 attribute = to_slab_attr(attr);
6654 if (!attribute->store)
6657 return attribute->store(s, buf, len);
6660 static void kmem_cache_release(struct kobject *k)
6662 slab_kmem_cache_release(to_slab(k));
6665 static const struct sysfs_ops slab_sysfs_ops = {
6666 .show = slab_attr_show,
6667 .store = slab_attr_store,
6670 static const struct kobj_type slab_ktype = {
6671 .sysfs_ops = &slab_sysfs_ops,
6672 .release = kmem_cache_release,
6675 static struct kset *slab_kset;
6677 static inline struct kset *cache_kset(struct kmem_cache *s)
6682 #define ID_STR_LENGTH 32
6684 /* Create a unique string id for a slab cache:
6686 * Format :[flags-]size
6688 static char *create_unique_id(struct kmem_cache *s)
6690 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
6694 return ERR_PTR(-ENOMEM);
6698 * First flags affecting slabcache operations. We will only
6699 * get here for aliasable slabs so we do not need to support
6700 * too many flags. The flags here must cover all flags that
6701 * are matched during merging to guarantee that the id is
6704 if (s->flags & SLAB_CACHE_DMA)
6706 if (s->flags & SLAB_CACHE_DMA32)
6708 if (s->flags & SLAB_RECLAIM_ACCOUNT)
6710 if (s->flags & SLAB_CONSISTENCY_CHECKS)
6712 if (s->flags & SLAB_ACCOUNT)
6716 p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
6718 if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
6720 return ERR_PTR(-EINVAL);
6722 kmsan_unpoison_memory(name, p - name);
6726 static int sysfs_slab_add(struct kmem_cache *s)
6730 struct kset *kset = cache_kset(s);
6731 int unmergeable = slab_unmergeable(s);
6733 if (!unmergeable && disable_higher_order_debug &&
6734 (slub_debug & DEBUG_METADATA_FLAGS))
6739 * Slabcache can never be merged so we can use the name proper.
6740 * This is typically the case for debug situations. In that
6741 * case we can catch duplicate names easily.
6743 sysfs_remove_link(&slab_kset->kobj, s->name);
6747 * Create a unique name for the slab as a target
6750 name = create_unique_id(s);
6752 return PTR_ERR(name);
6755 s->kobj.kset = kset;
6756 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
6760 err = sysfs_create_group(&s->kobj, &slab_attr_group);
6765 /* Setup first alias */
6766 sysfs_slab_alias(s, s->name);
6773 kobject_del(&s->kobj);
6777 void sysfs_slab_unlink(struct kmem_cache *s)
6779 kobject_del(&s->kobj);
6782 void sysfs_slab_release(struct kmem_cache *s)
6784 kobject_put(&s->kobj);
6788 * Need to buffer aliases during bootup until sysfs becomes
6789 * available lest we lose that information.
6791 struct saved_alias {
6792 struct kmem_cache *s;
6794 struct saved_alias *next;
6797 static struct saved_alias *alias_list;
6799 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
6801 struct saved_alias *al;
6803 if (slab_state == FULL) {
6805 * If we have a leftover link then remove it.
6807 sysfs_remove_link(&slab_kset->kobj, name);
6808 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
6811 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
6817 al->next = alias_list;
6819 kmsan_unpoison_memory(al, sizeof(*al));
6823 static int __init slab_sysfs_init(void)
6825 struct kmem_cache *s;
6828 mutex_lock(&slab_mutex);
6830 slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
6832 mutex_unlock(&slab_mutex);
6833 pr_err("Cannot register slab subsystem.\n");
6839 list_for_each_entry(s, &slab_caches, list) {
6840 err = sysfs_slab_add(s);
6842 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
6846 while (alias_list) {
6847 struct saved_alias *al = alias_list;
6849 alias_list = alias_list->next;
6850 err = sysfs_slab_alias(al->s, al->name);
6852 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
6857 mutex_unlock(&slab_mutex);
6860 late_initcall(slab_sysfs_init);
6861 #endif /* SLAB_SUPPORTS_SYSFS */
6863 #if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
6864 static int slab_debugfs_show(struct seq_file *seq, void *v)
6866 struct loc_track *t = seq->private;
6870 idx = (unsigned long) t->idx;
6871 if (idx < t->count) {
6874 seq_printf(seq, "%7ld ", l->count);
6877 seq_printf(seq, "%pS", (void *)l->addr);
6879 seq_puts(seq, "<not-available>");
6882 seq_printf(seq, " waste=%lu/%lu",
6883 l->count * l->waste, l->waste);
6885 if (l->sum_time != l->min_time) {
6886 seq_printf(seq, " age=%ld/%llu/%ld",
6887 l->min_time, div_u64(l->sum_time, l->count),
6890 seq_printf(seq, " age=%ld", l->min_time);
6892 if (l->min_pid != l->max_pid)
6893 seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
6895 seq_printf(seq, " pid=%ld",
6898 if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
6899 seq_printf(seq, " cpus=%*pbl",
6900 cpumask_pr_args(to_cpumask(l->cpus)));
6902 if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
6903 seq_printf(seq, " nodes=%*pbl",
6904 nodemask_pr_args(&l->nodes));
6906 #ifdef CONFIG_STACKDEPOT
6908 depot_stack_handle_t handle;
6909 unsigned long *entries;
6910 unsigned int nr_entries, j;
6912 handle = READ_ONCE(l->handle);
6914 nr_entries = stack_depot_fetch(handle, &entries);
6915 seq_puts(seq, "\n");
6916 for (j = 0; j < nr_entries; j++)
6917 seq_printf(seq, " %pS\n", (void *)entries[j]);
6921 seq_puts(seq, "\n");
6924 if (!idx && !t->count)
6925 seq_puts(seq, "No data\n");
6930 static void slab_debugfs_stop(struct seq_file *seq, void *v)
6934 static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
6936 struct loc_track *t = seq->private;
6939 if (*ppos <= t->count)
6945 static int cmp_loc_by_count(const void *a, const void *b, const void *data)
6947 struct location *loc1 = (struct location *)a;
6948 struct location *loc2 = (struct location *)b;
6950 if (loc1->count > loc2->count)
6956 static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
6958 struct loc_track *t = seq->private;
6964 static const struct seq_operations slab_debugfs_sops = {
6965 .start = slab_debugfs_start,
6966 .next = slab_debugfs_next,
6967 .stop = slab_debugfs_stop,
6968 .show = slab_debugfs_show,
6971 static int slab_debug_trace_open(struct inode *inode, struct file *filep)
6974 struct kmem_cache_node *n;
6975 enum track_item alloc;
6977 struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
6978 sizeof(struct loc_track));
6979 struct kmem_cache *s = file_inode(filep)->i_private;
6980 unsigned long *obj_map;
6985 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
6987 seq_release_private(inode, filep);
6991 if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
6992 alloc = TRACK_ALLOC;
6996 if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
6997 bitmap_free(obj_map);
6998 seq_release_private(inode, filep);
7002 for_each_kmem_cache_node(s, node, n) {
7003 unsigned long flags;
7006 if (!node_nr_slabs(n))
7009 spin_lock_irqsave(&n->list_lock, flags);
7010 list_for_each_entry(slab, &n->partial, slab_list)
7011 process_slab(t, s, slab, alloc, obj_map);
7012 list_for_each_entry(slab, &n->full, slab_list)
7013 process_slab(t, s, slab, alloc, obj_map);
7014 spin_unlock_irqrestore(&n->list_lock, flags);
7017 /* Sort locations by count */
7018 sort_r(t->loc, t->count, sizeof(struct location),
7019 cmp_loc_by_count, NULL, NULL);
7021 bitmap_free(obj_map);
7025 static int slab_debug_trace_release(struct inode *inode, struct file *file)
7027 struct seq_file *seq = file->private_data;
7028 struct loc_track *t = seq->private;
7031 return seq_release_private(inode, file);
7034 static const struct file_operations slab_debugfs_fops = {
7035 .open = slab_debug_trace_open,
7037 .llseek = seq_lseek,
7038 .release = slab_debug_trace_release,
7041 static void debugfs_slab_add(struct kmem_cache *s)
7043 struct dentry *slab_cache_dir;
7045 if (unlikely(!slab_debugfs_root))
7048 slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
7050 debugfs_create_file("alloc_traces", 0400,
7051 slab_cache_dir, s, &slab_debugfs_fops);
7053 debugfs_create_file("free_traces", 0400,
7054 slab_cache_dir, s, &slab_debugfs_fops);
7057 void debugfs_slab_release(struct kmem_cache *s)
7059 debugfs_lookup_and_remove(s->name, slab_debugfs_root);
7062 static int __init slab_debugfs_init(void)
7064 struct kmem_cache *s;
7066 slab_debugfs_root = debugfs_create_dir("slab", NULL);
7068 list_for_each_entry(s, &slab_caches, list)
7069 if (s->flags & SLAB_STORE_USER)
7070 debugfs_slab_add(s);
7075 __initcall(slab_debugfs_init);
7078 * The /proc/slabinfo ABI
7080 #ifdef CONFIG_SLUB_DEBUG
7081 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
7083 unsigned long nr_slabs = 0;
7084 unsigned long nr_objs = 0;
7085 unsigned long nr_free = 0;
7087 struct kmem_cache_node *n;
7089 for_each_kmem_cache_node(s, node, n) {
7090 nr_slabs += node_nr_slabs(n);
7091 nr_objs += node_nr_objs(n);
7092 nr_free += count_partial(n, count_free);
7095 sinfo->active_objs = nr_objs - nr_free;
7096 sinfo->num_objs = nr_objs;
7097 sinfo->active_slabs = nr_slabs;
7098 sinfo->num_slabs = nr_slabs;
7099 sinfo->objects_per_slab = oo_objects(s->oo);
7100 sinfo->cache_order = oo_order(s->oo);
7103 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
7107 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
7108 size_t count, loff_t *ppos)
7112 #endif /* CONFIG_SLUB_DEBUG */