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> /* struct reclaim_state */
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/cpu.h>
26 #include <linux/cpuset.h>
27 #include <linux/mempolicy.h>
28 #include <linux/ctype.h>
29 #include <linux/stackdepot.h>
30 #include <linux/debugobjects.h>
31 #include <linux/kallsyms.h>
32 #include <linux/kfence.h>
33 #include <linux/memory.h>
34 #include <linux/math64.h>
35 #include <linux/fault-inject.h>
36 #include <linux/stacktrace.h>
37 #include <linux/prefetch.h>
38 #include <linux/memcontrol.h>
39 #include <linux/random.h>
40 #include <kunit/test.h>
41 #include <linux/sort.h>
43 #include <linux/debugfs.h>
44 #include <trace/events/kmem.h>
50 * 1. slab_mutex (Global Mutex)
51 * 2. node->list_lock (Spinlock)
52 * 3. kmem_cache->cpu_slab->lock (Local lock)
53 * 4. slab_lock(slab) (Only on some arches or for debugging)
54 * 5. object_map_lock (Only for debugging)
58 * The role of the slab_mutex is to protect the list of all the slabs
59 * and to synchronize major metadata changes to slab cache structures.
60 * Also synchronizes memory hotplug callbacks.
64 * The slab_lock is a wrapper around the page lock, thus it is a bit
67 * The slab_lock is only used for debugging and on arches that do not
68 * have the ability to do a cmpxchg_double. It only protects:
69 * A. slab->freelist -> List of free objects in a slab
70 * B. slab->inuse -> Number of objects in use
71 * C. slab->objects -> Number of objects in slab
72 * D. slab->frozen -> frozen state
76 * If a slab is frozen then it is exempt from list management. It is not
77 * on any list except per cpu partial list. The processor that froze the
78 * slab is the one who can perform list operations on the slab. Other
79 * processors may put objects onto the freelist but the processor that
80 * froze the slab is the only one that can retrieve the objects from the
85 * The list_lock protects the partial and full list on each node and
86 * the partial slab counter. If taken then no new slabs may be added or
87 * removed from the lists nor make the number of partial slabs be modified.
88 * (Note that the total number of slabs is an atomic value that may be
89 * modified without taking the list lock).
91 * The list_lock is a centralized lock and thus we avoid taking it as
92 * much as possible. As long as SLUB does not have to handle partial
93 * slabs, operations can continue without any centralized lock. F.e.
94 * allocating a long series of objects that fill up slabs does not require
97 * cpu_slab->lock local lock
99 * This locks protect slowpath manipulation of all kmem_cache_cpu fields
100 * except the stat counters. This is a percpu structure manipulated only by
101 * the local cpu, so the lock protects against being preempted or interrupted
102 * by an irq. Fast path operations rely on lockless operations instead.
103 * On PREEMPT_RT, the local lock does not actually disable irqs (and thus
104 * prevent the lockless operations), so fastpath operations also need to take
105 * the lock and are no longer lockless.
109 * The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
110 * are fully lockless when satisfied from the percpu slab (and when
111 * cmpxchg_double is possible to use, otherwise slab_lock is taken).
112 * They also don't disable preemption or migration or irqs. They rely on
113 * the transaction id (tid) field to detect being preempted or moved to
116 * irq, preemption, migration considerations
118 * Interrupts are disabled as part of list_lock or local_lock operations, or
119 * around the slab_lock operation, in order to make the slab allocator safe
120 * to use in the context of an irq.
122 * In addition, preemption (or migration on PREEMPT_RT) is disabled in the
123 * allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
124 * local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
125 * doesn't have to be revalidated in each section protected by the local lock.
127 * SLUB assigns one slab for allocation to each processor.
128 * Allocations only occur from these slabs called cpu slabs.
130 * Slabs with free elements are kept on a partial list and during regular
131 * operations no list for full slabs is used. If an object in a full slab is
132 * freed then the slab will show up again on the partial lists.
133 * We track full slabs for debugging purposes though because otherwise we
134 * cannot scan all objects.
136 * Slabs are freed when they become empty. Teardown and setup is
137 * minimal so we rely on the page allocators per cpu caches for
138 * fast frees and allocs.
140 * slab->frozen The slab is frozen and exempt from list processing.
141 * This means that the slab is dedicated to a purpose
142 * such as satisfying allocations for a specific
143 * processor. Objects may be freed in the slab while
144 * it is frozen but slab_free will then skip the usual
145 * list operations. It is up to the processor holding
146 * the slab to integrate the slab into the slab lists
147 * when the slab is no longer needed.
149 * One use of this flag is to mark slabs that are
150 * used for allocations. Then such a slab becomes a cpu
151 * slab. The cpu slab may be equipped with an additional
152 * freelist that allows lockless access to
153 * free objects in addition to the regular freelist
154 * that requires the slab lock.
156 * SLAB_DEBUG_FLAGS Slab requires special handling due to debug
157 * options set. This moves slab handling out of
158 * the fast path and disables lockless freelists.
162 * We could simply use migrate_disable()/enable() but as long as it's a
163 * function call even on !PREEMPT_RT, use inline preempt_disable() there.
165 #ifndef CONFIG_PREEMPT_RT
166 #define slub_get_cpu_ptr(var) get_cpu_ptr(var)
167 #define slub_put_cpu_ptr(var) put_cpu_ptr(var)
169 #define slub_get_cpu_ptr(var) \
174 #define slub_put_cpu_ptr(var) \
181 #ifdef CONFIG_SLUB_DEBUG
182 #ifdef CONFIG_SLUB_DEBUG_ON
183 DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
185 DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
187 #endif /* CONFIG_SLUB_DEBUG */
189 static inline bool kmem_cache_debug(struct kmem_cache *s)
191 return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
194 void *fixup_red_left(struct kmem_cache *s, void *p)
196 if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
197 p += s->red_left_pad;
202 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
204 #ifdef CONFIG_SLUB_CPU_PARTIAL
205 return !kmem_cache_debug(s);
212 * Issues still to be resolved:
214 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
216 * - Variable sizing of the per node arrays
219 /* Enable to log cmpxchg failures */
220 #undef SLUB_DEBUG_CMPXCHG
223 * Minimum number of partial slabs. These will be left on the partial
224 * lists even if they are empty. kmem_cache_shrink may reclaim them.
226 #define MIN_PARTIAL 5
229 * Maximum number of desirable partial slabs.
230 * The existence of more partial slabs makes kmem_cache_shrink
231 * sort the partial list by the number of objects in use.
233 #define MAX_PARTIAL 10
235 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
236 SLAB_POISON | SLAB_STORE_USER)
239 * These debug flags cannot use CMPXCHG because there might be consistency
240 * issues when checking or reading debug information
242 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
247 * Debugging flags that require metadata to be stored in the slab. These get
248 * disabled when slub_debug=O is used and a cache's min order increases with
251 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
254 #define OO_MASK ((1 << OO_SHIFT) - 1)
255 #define MAX_OBJS_PER_PAGE 32767 /* since slab.objects is u15 */
257 /* Internal SLUB flags */
259 #define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
260 /* Use cmpxchg_double */
261 #define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
264 * Tracking user of a slab.
266 #define TRACK_ADDRS_COUNT 16
268 unsigned long addr; /* Called from address */
269 #ifdef CONFIG_STACKDEPOT
270 depot_stack_handle_t handle;
272 int cpu; /* Was running on cpu */
273 int pid; /* Pid context */
274 unsigned long when; /* When did the operation occur */
277 enum track_item { TRACK_ALLOC, TRACK_FREE };
280 static int sysfs_slab_add(struct kmem_cache *);
281 static int sysfs_slab_alias(struct kmem_cache *, const char *);
283 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
284 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
288 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
289 static void debugfs_slab_add(struct kmem_cache *);
291 static inline void debugfs_slab_add(struct kmem_cache *s) { }
294 static inline void stat(const struct kmem_cache *s, enum stat_item si)
296 #ifdef CONFIG_SLUB_STATS
298 * The rmw is racy on a preemptible kernel but this is acceptable, so
299 * avoid this_cpu_add()'s irq-disable overhead.
301 raw_cpu_inc(s->cpu_slab->stat[si]);
306 * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
307 * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
308 * differ during memory hotplug/hotremove operations.
309 * Protected by slab_mutex.
311 static nodemask_t slab_nodes;
313 /********************************************************************
314 * Core slab cache functions
315 *******************************************************************/
318 * Returns freelist pointer (ptr). With hardening, this is obfuscated
319 * with an XOR of the address where the pointer is held and a per-cache
322 static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
323 unsigned long ptr_addr)
325 #ifdef CONFIG_SLAB_FREELIST_HARDENED
327 * When CONFIG_KASAN_SW/HW_TAGS is enabled, ptr_addr might be tagged.
328 * Normally, this doesn't cause any issues, as both set_freepointer()
329 * and get_freepointer() are called with a pointer with the same tag.
330 * However, there are some issues with CONFIG_SLUB_DEBUG code. For
331 * example, when __free_slub() iterates over objects in a cache, it
332 * passes untagged pointers to check_object(). check_object() in turns
333 * calls get_freepointer() with an untagged pointer, which causes the
334 * freepointer to be restored incorrectly.
336 return (void *)((unsigned long)ptr ^ s->random ^
337 swab((unsigned long)kasan_reset_tag((void *)ptr_addr)));
343 /* Returns the freelist pointer recorded at location ptr_addr. */
344 static inline void *freelist_dereference(const struct kmem_cache *s,
347 return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
348 (unsigned long)ptr_addr);
351 static inline void *get_freepointer(struct kmem_cache *s, void *object)
353 object = kasan_reset_tag(object);
354 return freelist_dereference(s, object + s->offset);
357 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
359 prefetchw(object + s->offset);
362 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
364 unsigned long freepointer_addr;
367 if (!debug_pagealloc_enabled_static())
368 return get_freepointer(s, object);
370 object = kasan_reset_tag(object);
371 freepointer_addr = (unsigned long)object + s->offset;
372 copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
373 return freelist_ptr(s, p, freepointer_addr);
376 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
378 unsigned long freeptr_addr = (unsigned long)object + s->offset;
380 #ifdef CONFIG_SLAB_FREELIST_HARDENED
381 BUG_ON(object == fp); /* naive detection of double free or corruption */
384 freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
385 *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
388 /* Loop over all objects in a slab */
389 #define for_each_object(__p, __s, __addr, __objects) \
390 for (__p = fixup_red_left(__s, __addr); \
391 __p < (__addr) + (__objects) * (__s)->size; \
394 static inline unsigned int order_objects(unsigned int order, unsigned int size)
396 return ((unsigned int)PAGE_SIZE << order) / size;
399 static inline struct kmem_cache_order_objects oo_make(unsigned int order,
402 struct kmem_cache_order_objects x = {
403 (order << OO_SHIFT) + order_objects(order, size)
409 static inline unsigned int oo_order(struct kmem_cache_order_objects x)
411 return x.x >> OO_SHIFT;
414 static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
416 return x.x & OO_MASK;
419 #ifdef CONFIG_SLUB_CPU_PARTIAL
420 static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
422 unsigned int nr_slabs;
424 s->cpu_partial = nr_objects;
427 * We take the number of objects but actually limit the number of
428 * slabs on the per cpu partial list, in order to limit excessive
429 * growth of the list. For simplicity we assume that the slabs will
432 nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
433 s->cpu_partial_slabs = nr_slabs;
437 slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
440 #endif /* CONFIG_SLUB_CPU_PARTIAL */
443 * Per slab locking using the pagelock
445 static __always_inline void __slab_lock(struct slab *slab)
447 struct page *page = slab_page(slab);
449 VM_BUG_ON_PAGE(PageTail(page), page);
450 bit_spin_lock(PG_locked, &page->flags);
453 static __always_inline void __slab_unlock(struct slab *slab)
455 struct page *page = slab_page(slab);
457 VM_BUG_ON_PAGE(PageTail(page), page);
458 __bit_spin_unlock(PG_locked, &page->flags);
461 static __always_inline void slab_lock(struct slab *slab, unsigned long *flags)
463 if (IS_ENABLED(CONFIG_PREEMPT_RT))
464 local_irq_save(*flags);
468 static __always_inline void slab_unlock(struct slab *slab, unsigned long *flags)
471 if (IS_ENABLED(CONFIG_PREEMPT_RT))
472 local_irq_restore(*flags);
476 * Interrupts must be disabled (for the fallback code to work right), typically
477 * by an _irqsave() lock variant. Except on PREEMPT_RT where locks are different
478 * so we disable interrupts as part of slab_[un]lock().
480 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
481 void *freelist_old, unsigned long counters_old,
482 void *freelist_new, unsigned long counters_new,
485 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
486 lockdep_assert_irqs_disabled();
487 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
488 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
489 if (s->flags & __CMPXCHG_DOUBLE) {
490 if (cmpxchg_double(&slab->freelist, &slab->counters,
491 freelist_old, counters_old,
492 freelist_new, counters_new))
497 /* init to 0 to prevent spurious warnings */
498 unsigned long flags = 0;
500 slab_lock(slab, &flags);
501 if (slab->freelist == freelist_old &&
502 slab->counters == counters_old) {
503 slab->freelist = freelist_new;
504 slab->counters = counters_new;
505 slab_unlock(slab, &flags);
508 slab_unlock(slab, &flags);
512 stat(s, CMPXCHG_DOUBLE_FAIL);
514 #ifdef SLUB_DEBUG_CMPXCHG
515 pr_info("%s %s: cmpxchg double redo ", n, s->name);
521 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
522 void *freelist_old, unsigned long counters_old,
523 void *freelist_new, unsigned long counters_new,
526 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
527 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
528 if (s->flags & __CMPXCHG_DOUBLE) {
529 if (cmpxchg_double(&slab->freelist, &slab->counters,
530 freelist_old, counters_old,
531 freelist_new, counters_new))
538 local_irq_save(flags);
540 if (slab->freelist == freelist_old &&
541 slab->counters == counters_old) {
542 slab->freelist = freelist_new;
543 slab->counters = counters_new;
545 local_irq_restore(flags);
549 local_irq_restore(flags);
553 stat(s, CMPXCHG_DOUBLE_FAIL);
555 #ifdef SLUB_DEBUG_CMPXCHG
556 pr_info("%s %s: cmpxchg double redo ", n, s->name);
562 #ifdef CONFIG_SLUB_DEBUG
563 static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
564 static DEFINE_RAW_SPINLOCK(object_map_lock);
566 static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
569 void *addr = slab_address(slab);
572 bitmap_zero(obj_map, slab->objects);
574 for (p = slab->freelist; p; p = get_freepointer(s, p))
575 set_bit(__obj_to_index(s, addr, p), obj_map);
578 #if IS_ENABLED(CONFIG_KUNIT)
579 static bool slab_add_kunit_errors(void)
581 struct kunit_resource *resource;
583 if (likely(!current->kunit_test))
586 resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
590 (*(int *)resource->data)++;
591 kunit_put_resource(resource);
595 static inline bool slab_add_kunit_errors(void) { return false; }
599 * Determine a map of objects in use in a slab.
601 * Node listlock must be held to guarantee that the slab does
602 * not vanish from under us.
604 static unsigned long *get_map(struct kmem_cache *s, struct slab *slab)
605 __acquires(&object_map_lock)
607 VM_BUG_ON(!irqs_disabled());
609 raw_spin_lock(&object_map_lock);
611 __fill_map(object_map, s, slab);
616 static void put_map(unsigned long *map) __releases(&object_map_lock)
618 VM_BUG_ON(map != object_map);
619 raw_spin_unlock(&object_map_lock);
622 static inline unsigned int size_from_object(struct kmem_cache *s)
624 if (s->flags & SLAB_RED_ZONE)
625 return s->size - s->red_left_pad;
630 static inline void *restore_red_left(struct kmem_cache *s, void *p)
632 if (s->flags & SLAB_RED_ZONE)
633 p -= s->red_left_pad;
641 #if defined(CONFIG_SLUB_DEBUG_ON)
642 static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
644 static slab_flags_t slub_debug;
647 static char *slub_debug_string;
648 static int disable_higher_order_debug;
651 * slub is about to manipulate internal object metadata. This memory lies
652 * outside the range of the allocated object, so accessing it would normally
653 * be reported by kasan as a bounds error. metadata_access_enable() is used
654 * to tell kasan that these accesses are OK.
656 static inline void metadata_access_enable(void)
658 kasan_disable_current();
661 static inline void metadata_access_disable(void)
663 kasan_enable_current();
670 /* Verify that a pointer has an address that is valid within a slab page */
671 static inline int check_valid_pointer(struct kmem_cache *s,
672 struct slab *slab, void *object)
679 base = slab_address(slab);
680 object = kasan_reset_tag(object);
681 object = restore_red_left(s, object);
682 if (object < base || object >= base + slab->objects * s->size ||
683 (object - base) % s->size) {
690 static void print_section(char *level, char *text, u8 *addr,
693 metadata_access_enable();
694 print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
695 16, 1, kasan_reset_tag((void *)addr), length, 1);
696 metadata_access_disable();
700 * See comment in calculate_sizes().
702 static inline bool freeptr_outside_object(struct kmem_cache *s)
704 return s->offset >= s->inuse;
708 * Return offset of the end of info block which is inuse + free pointer if
709 * not overlapping with object.
711 static inline unsigned int get_info_end(struct kmem_cache *s)
713 if (freeptr_outside_object(s))
714 return s->inuse + sizeof(void *);
719 static struct track *get_track(struct kmem_cache *s, void *object,
720 enum track_item alloc)
724 p = object + get_info_end(s);
726 return kasan_reset_tag(p + alloc);
729 #ifdef CONFIG_STACKDEPOT
730 static noinline depot_stack_handle_t set_track_prepare(void)
732 depot_stack_handle_t handle;
733 unsigned long entries[TRACK_ADDRS_COUNT];
734 unsigned int nr_entries;
736 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
737 handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
742 static inline depot_stack_handle_t set_track_prepare(void)
748 static void set_track_update(struct kmem_cache *s, void *object,
749 enum track_item alloc, unsigned long addr,
750 depot_stack_handle_t handle)
752 struct track *p = get_track(s, object, alloc);
754 #ifdef CONFIG_STACKDEPOT
758 p->cpu = smp_processor_id();
759 p->pid = current->pid;
763 static __always_inline void set_track(struct kmem_cache *s, void *object,
764 enum track_item alloc, unsigned long addr)
766 depot_stack_handle_t handle = set_track_prepare();
768 set_track_update(s, object, alloc, addr, handle);
771 static void init_tracking(struct kmem_cache *s, void *object)
775 if (!(s->flags & SLAB_STORE_USER))
778 p = get_track(s, object, TRACK_ALLOC);
779 memset(p, 0, 2*sizeof(struct track));
782 static void print_track(const char *s, struct track *t, unsigned long pr_time)
784 depot_stack_handle_t handle __maybe_unused;
789 pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
790 s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
791 #ifdef CONFIG_STACKDEPOT
792 handle = READ_ONCE(t->handle);
794 stack_depot_print(handle);
796 pr_err("object allocation/free stack trace missing\n");
800 void print_tracking(struct kmem_cache *s, void *object)
802 unsigned long pr_time = jiffies;
803 if (!(s->flags & SLAB_STORE_USER))
806 print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
807 print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
810 static void print_slab_info(const struct slab *slab)
812 struct folio *folio = (struct folio *)slab_folio(slab);
814 pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
815 slab, slab->objects, slab->inuse, slab->freelist,
816 folio_flags(folio, 0));
819 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
821 struct va_format vaf;
827 pr_err("=============================================================================\n");
828 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
829 pr_err("-----------------------------------------------------------------------------\n\n");
834 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
836 struct va_format vaf;
839 if (slab_add_kunit_errors())
845 pr_err("FIX %s: %pV\n", s->name, &vaf);
849 static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
851 unsigned int off; /* Offset of last byte */
852 u8 *addr = slab_address(slab);
854 print_tracking(s, p);
856 print_slab_info(slab);
858 pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
859 p, p - addr, get_freepointer(s, p));
861 if (s->flags & SLAB_RED_ZONE)
862 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
864 else if (p > addr + 16)
865 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
867 print_section(KERN_ERR, "Object ", p,
868 min_t(unsigned int, s->object_size, PAGE_SIZE));
869 if (s->flags & SLAB_RED_ZONE)
870 print_section(KERN_ERR, "Redzone ", p + s->object_size,
871 s->inuse - s->object_size);
873 off = get_info_end(s);
875 if (s->flags & SLAB_STORE_USER)
876 off += 2 * sizeof(struct track);
878 off += kasan_metadata_size(s);
880 if (off != size_from_object(s))
881 /* Beginning of the filler is the free pointer */
882 print_section(KERN_ERR, "Padding ", p + off,
883 size_from_object(s) - off);
888 static void object_err(struct kmem_cache *s, struct slab *slab,
889 u8 *object, char *reason)
891 if (slab_add_kunit_errors())
894 slab_bug(s, "%s", reason);
895 print_trailer(s, slab, object);
896 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
899 static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
900 void **freelist, void *nextfree)
902 if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
903 !check_valid_pointer(s, slab, nextfree) && freelist) {
904 object_err(s, slab, *freelist, "Freechain corrupt");
906 slab_fix(s, "Isolate corrupted freechain");
913 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
914 const char *fmt, ...)
919 if (slab_add_kunit_errors())
923 vsnprintf(buf, sizeof(buf), fmt, args);
925 slab_bug(s, "%s", buf);
926 print_slab_info(slab);
928 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
931 static void init_object(struct kmem_cache *s, void *object, u8 val)
933 u8 *p = kasan_reset_tag(object);
935 if (s->flags & SLAB_RED_ZONE)
936 memset(p - s->red_left_pad, val, s->red_left_pad);
938 if (s->flags & __OBJECT_POISON) {
939 memset(p, POISON_FREE, s->object_size - 1);
940 p[s->object_size - 1] = POISON_END;
943 if (s->flags & SLAB_RED_ZONE)
944 memset(p + s->object_size, val, s->inuse - s->object_size);
947 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
948 void *from, void *to)
950 slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
951 memset(from, data, to - from);
954 static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
955 u8 *object, char *what,
956 u8 *start, unsigned int value, unsigned int bytes)
960 u8 *addr = slab_address(slab);
962 metadata_access_enable();
963 fault = memchr_inv(kasan_reset_tag(start), value, bytes);
964 metadata_access_disable();
969 while (end > fault && end[-1] == value)
972 if (slab_add_kunit_errors())
975 slab_bug(s, "%s overwritten", what);
976 pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
977 fault, end - 1, fault - addr,
979 print_trailer(s, slab, object);
980 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
983 restore_bytes(s, what, value, fault, end);
991 * Bytes of the object to be managed.
992 * If the freepointer may overlay the object then the free
993 * pointer is at the middle of the object.
995 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
998 * object + s->object_size
999 * Padding to reach word boundary. This is also used for Redzoning.
1000 * Padding is extended by another word if Redzoning is enabled and
1001 * object_size == inuse.
1003 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
1004 * 0xcc (RED_ACTIVE) for objects in use.
1007 * Meta data starts here.
1009 * A. Free pointer (if we cannot overwrite object on free)
1010 * B. Tracking data for SLAB_STORE_USER
1011 * C. Padding to reach required alignment boundary or at minimum
1012 * one word if debugging is on to be able to detect writes
1013 * before the word boundary.
1015 * Padding is done using 0x5a (POISON_INUSE)
1018 * Nothing is used beyond s->size.
1020 * If slabcaches are merged then the object_size and inuse boundaries are mostly
1021 * ignored. And therefore no slab options that rely on these boundaries
1022 * may be used with merged slabcaches.
1025 static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
1027 unsigned long off = get_info_end(s); /* The end of info */
1029 if (s->flags & SLAB_STORE_USER)
1030 /* We also have user information there */
1031 off += 2 * sizeof(struct track);
1033 off += kasan_metadata_size(s);
1035 if (size_from_object(s) == off)
1038 return check_bytes_and_report(s, slab, p, "Object padding",
1039 p + off, POISON_INUSE, size_from_object(s) - off);
1042 /* Check the pad bytes at the end of a slab page */
1043 static void slab_pad_check(struct kmem_cache *s, struct slab *slab)
1052 if (!(s->flags & SLAB_POISON))
1055 start = slab_address(slab);
1056 length = slab_size(slab);
1057 end = start + length;
1058 remainder = length % s->size;
1062 pad = end - remainder;
1063 metadata_access_enable();
1064 fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
1065 metadata_access_disable();
1068 while (end > fault && end[-1] == POISON_INUSE)
1071 slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
1072 fault, end - 1, fault - start);
1073 print_section(KERN_ERR, "Padding ", pad, remainder);
1075 restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
1078 static int check_object(struct kmem_cache *s, struct slab *slab,
1079 void *object, u8 val)
1082 u8 *endobject = object + s->object_size;
1084 if (s->flags & SLAB_RED_ZONE) {
1085 if (!check_bytes_and_report(s, slab, object, "Left Redzone",
1086 object - s->red_left_pad, val, s->red_left_pad))
1089 if (!check_bytes_and_report(s, slab, object, "Right Redzone",
1090 endobject, val, s->inuse - s->object_size))
1093 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
1094 check_bytes_and_report(s, slab, p, "Alignment padding",
1095 endobject, POISON_INUSE,
1096 s->inuse - s->object_size);
1100 if (s->flags & SLAB_POISON) {
1101 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
1102 (!check_bytes_and_report(s, slab, p, "Poison", p,
1103 POISON_FREE, s->object_size - 1) ||
1104 !check_bytes_and_report(s, slab, p, "End Poison",
1105 p + s->object_size - 1, POISON_END, 1)))
1108 * check_pad_bytes cleans up on its own.
1110 check_pad_bytes(s, slab, p);
1113 if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
1115 * Object and freepointer overlap. Cannot check
1116 * freepointer while object is allocated.
1120 /* Check free pointer validity */
1121 if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
1122 object_err(s, slab, p, "Freepointer corrupt");
1124 * No choice but to zap it and thus lose the remainder
1125 * of the free objects in this slab. May cause
1126 * another error because the object count is now wrong.
1128 set_freepointer(s, p, NULL);
1134 static int check_slab(struct kmem_cache *s, struct slab *slab)
1138 if (!folio_test_slab(slab_folio(slab))) {
1139 slab_err(s, slab, "Not a valid slab page");
1143 maxobj = order_objects(slab_order(slab), s->size);
1144 if (slab->objects > maxobj) {
1145 slab_err(s, slab, "objects %u > max %u",
1146 slab->objects, maxobj);
1149 if (slab->inuse > slab->objects) {
1150 slab_err(s, slab, "inuse %u > max %u",
1151 slab->inuse, slab->objects);
1154 /* Slab_pad_check fixes things up after itself */
1155 slab_pad_check(s, slab);
1160 * Determine if a certain object in a slab is on the freelist. Must hold the
1161 * slab lock to guarantee that the chains are in a consistent state.
1163 static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
1167 void *object = NULL;
1170 fp = slab->freelist;
1171 while (fp && nr <= slab->objects) {
1174 if (!check_valid_pointer(s, slab, fp)) {
1176 object_err(s, slab, object,
1177 "Freechain corrupt");
1178 set_freepointer(s, object, NULL);
1180 slab_err(s, slab, "Freepointer corrupt");
1181 slab->freelist = NULL;
1182 slab->inuse = slab->objects;
1183 slab_fix(s, "Freelist cleared");
1189 fp = get_freepointer(s, object);
1193 max_objects = order_objects(slab_order(slab), s->size);
1194 if (max_objects > MAX_OBJS_PER_PAGE)
1195 max_objects = MAX_OBJS_PER_PAGE;
1197 if (slab->objects != max_objects) {
1198 slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
1199 slab->objects, max_objects);
1200 slab->objects = max_objects;
1201 slab_fix(s, "Number of objects adjusted");
1203 if (slab->inuse != slab->objects - nr) {
1204 slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
1205 slab->inuse, slab->objects - nr);
1206 slab->inuse = slab->objects - nr;
1207 slab_fix(s, "Object count adjusted");
1209 return search == NULL;
1212 static void trace(struct kmem_cache *s, struct slab *slab, void *object,
1215 if (s->flags & SLAB_TRACE) {
1216 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1218 alloc ? "alloc" : "free",
1219 object, slab->inuse,
1223 print_section(KERN_INFO, "Object ", (void *)object,
1231 * Tracking of fully allocated slabs for debugging purposes.
1233 static void add_full(struct kmem_cache *s,
1234 struct kmem_cache_node *n, struct slab *slab)
1236 if (!(s->flags & SLAB_STORE_USER))
1239 lockdep_assert_held(&n->list_lock);
1240 list_add(&slab->slab_list, &n->full);
1243 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
1245 if (!(s->flags & SLAB_STORE_USER))
1248 lockdep_assert_held(&n->list_lock);
1249 list_del(&slab->slab_list);
1252 /* Tracking of the number of slabs for debugging purposes */
1253 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1255 struct kmem_cache_node *n = get_node(s, node);
1257 return atomic_long_read(&n->nr_slabs);
1260 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1262 return atomic_long_read(&n->nr_slabs);
1265 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1267 struct kmem_cache_node *n = get_node(s, node);
1270 * May be called early in order to allocate a slab for the
1271 * kmem_cache_node structure. Solve the chicken-egg
1272 * dilemma by deferring the increment of the count during
1273 * bootstrap (see early_kmem_cache_node_alloc).
1276 atomic_long_inc(&n->nr_slabs);
1277 atomic_long_add(objects, &n->total_objects);
1280 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1282 struct kmem_cache_node *n = get_node(s, node);
1284 atomic_long_dec(&n->nr_slabs);
1285 atomic_long_sub(objects, &n->total_objects);
1288 /* Object debug checks for alloc/free paths */
1289 static void setup_object_debug(struct kmem_cache *s, void *object)
1291 if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
1294 init_object(s, object, SLUB_RED_INACTIVE);
1295 init_tracking(s, object);
1299 void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
1301 if (!kmem_cache_debug_flags(s, SLAB_POISON))
1304 metadata_access_enable();
1305 memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
1306 metadata_access_disable();
1309 static inline int alloc_consistency_checks(struct kmem_cache *s,
1310 struct slab *slab, void *object)
1312 if (!check_slab(s, slab))
1315 if (!check_valid_pointer(s, slab, object)) {
1316 object_err(s, slab, object, "Freelist Pointer check fails");
1320 if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
1326 static noinline int alloc_debug_processing(struct kmem_cache *s,
1328 void *object, unsigned long addr)
1330 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1331 if (!alloc_consistency_checks(s, slab, object))
1335 /* Success perform special debug activities for allocs */
1336 if (s->flags & SLAB_STORE_USER)
1337 set_track(s, object, TRACK_ALLOC, addr);
1338 trace(s, slab, object, 1);
1339 init_object(s, object, SLUB_RED_ACTIVE);
1343 if (folio_test_slab(slab_folio(slab))) {
1345 * If this is a slab page then lets do the best we can
1346 * to avoid issues in the future. Marking all objects
1347 * as used avoids touching the remaining objects.
1349 slab_fix(s, "Marking all objects used");
1350 slab->inuse = slab->objects;
1351 slab->freelist = NULL;
1356 static inline int free_consistency_checks(struct kmem_cache *s,
1357 struct slab *slab, void *object, unsigned long addr)
1359 if (!check_valid_pointer(s, slab, object)) {
1360 slab_err(s, slab, "Invalid object pointer 0x%p", object);
1364 if (on_freelist(s, slab, object)) {
1365 object_err(s, slab, object, "Object already free");
1369 if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
1372 if (unlikely(s != slab->slab_cache)) {
1373 if (!folio_test_slab(slab_folio(slab))) {
1374 slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
1376 } else if (!slab->slab_cache) {
1377 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1381 object_err(s, slab, object,
1382 "page slab pointer corrupt.");
1388 /* Supports checking bulk free of a constructed freelist */
1389 static noinline int free_debug_processing(
1390 struct kmem_cache *s, struct slab *slab,
1391 void *head, void *tail, int bulk_cnt,
1394 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
1395 void *object = head;
1397 unsigned long flags, flags2;
1399 depot_stack_handle_t handle = 0;
1401 if (s->flags & SLAB_STORE_USER)
1402 handle = set_track_prepare();
1404 spin_lock_irqsave(&n->list_lock, flags);
1405 slab_lock(slab, &flags2);
1407 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1408 if (!check_slab(s, slab))
1415 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1416 if (!free_consistency_checks(s, slab, object, addr))
1420 if (s->flags & SLAB_STORE_USER)
1421 set_track_update(s, object, TRACK_FREE, addr, handle);
1422 trace(s, slab, object, 0);
1423 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1424 init_object(s, object, SLUB_RED_INACTIVE);
1426 /* Reached end of constructed freelist yet? */
1427 if (object != tail) {
1428 object = get_freepointer(s, object);
1434 if (cnt != bulk_cnt)
1435 slab_err(s, slab, "Bulk freelist count(%d) invalid(%d)\n",
1438 slab_unlock(slab, &flags2);
1439 spin_unlock_irqrestore(&n->list_lock, flags);
1441 slab_fix(s, "Object at 0x%p not freed", object);
1446 * Parse a block of slub_debug options. Blocks are delimited by ';'
1448 * @str: start of block
1449 * @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1450 * @slabs: return start of list of slabs, or NULL when there's no list
1451 * @init: assume this is initial parsing and not per-kmem-create parsing
1453 * returns the start of next block if there's any, or NULL
1456 parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
1458 bool higher_order_disable = false;
1460 /* Skip any completely empty blocks */
1461 while (*str && *str == ';')
1466 * No options but restriction on slabs. This means full
1467 * debugging for slabs matching a pattern.
1469 *flags = DEBUG_DEFAULT_FLAGS;
1474 /* Determine which debug features should be switched on */
1475 for (; *str && *str != ',' && *str != ';'; str++) {
1476 switch (tolower(*str)) {
1481 *flags |= SLAB_CONSISTENCY_CHECKS;
1484 *flags |= SLAB_RED_ZONE;
1487 *flags |= SLAB_POISON;
1490 *flags |= SLAB_STORE_USER;
1493 *flags |= SLAB_TRACE;
1496 *flags |= SLAB_FAILSLAB;
1500 * Avoid enabling debugging on caches if its minimum
1501 * order would increase as a result.
1503 higher_order_disable = true;
1507 pr_err("slub_debug option '%c' unknown. skipped\n", *str);
1516 /* Skip over the slab list */
1517 while (*str && *str != ';')
1520 /* Skip any completely empty blocks */
1521 while (*str && *str == ';')
1524 if (init && higher_order_disable)
1525 disable_higher_order_debug = 1;
1533 static int __init setup_slub_debug(char *str)
1536 slab_flags_t global_flags;
1539 bool global_slub_debug_changed = false;
1540 bool slab_list_specified = false;
1542 global_flags = DEBUG_DEFAULT_FLAGS;
1543 if (*str++ != '=' || !*str)
1545 * No options specified. Switch on full debugging.
1551 str = parse_slub_debug_flags(str, &flags, &slab_list, true);
1554 global_flags = flags;
1555 global_slub_debug_changed = true;
1557 slab_list_specified = true;
1558 if (flags & SLAB_STORE_USER)
1559 stack_depot_want_early_init();
1564 * For backwards compatibility, a single list of flags with list of
1565 * slabs means debugging is only changed for those slabs, so the global
1566 * slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
1567 * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
1568 * long as there is no option specifying flags without a slab list.
1570 if (slab_list_specified) {
1571 if (!global_slub_debug_changed)
1572 global_flags = slub_debug;
1573 slub_debug_string = saved_str;
1576 slub_debug = global_flags;
1577 if (slub_debug & SLAB_STORE_USER)
1578 stack_depot_want_early_init();
1579 if (slub_debug != 0 || slub_debug_string)
1580 static_branch_enable(&slub_debug_enabled);
1582 static_branch_disable(&slub_debug_enabled);
1583 if ((static_branch_unlikely(&init_on_alloc) ||
1584 static_branch_unlikely(&init_on_free)) &&
1585 (slub_debug & SLAB_POISON))
1586 pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1590 __setup("slub_debug", setup_slub_debug);
1593 * kmem_cache_flags - apply debugging options to the cache
1594 * @object_size: the size of an object without meta data
1595 * @flags: flags to set
1596 * @name: name of the cache
1598 * Debug option(s) are applied to @flags. In addition to the debug
1599 * option(s), if a slab name (or multiple) is specified i.e.
1600 * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1601 * then only the select slabs will receive the debug option(s).
1603 slab_flags_t kmem_cache_flags(unsigned int object_size,
1604 slab_flags_t flags, const char *name)
1609 slab_flags_t block_flags;
1610 slab_flags_t slub_debug_local = slub_debug;
1612 if (flags & SLAB_NO_USER_FLAGS)
1616 * If the slab cache is for debugging (e.g. kmemleak) then
1617 * don't store user (stack trace) information by default,
1618 * but let the user enable it via the command line below.
1620 if (flags & SLAB_NOLEAKTRACE)
1621 slub_debug_local &= ~SLAB_STORE_USER;
1624 next_block = slub_debug_string;
1625 /* Go through all blocks of debug options, see if any matches our slab's name */
1626 while (next_block) {
1627 next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
1630 /* Found a block that has a slab list, search it */
1635 end = strchrnul(iter, ',');
1636 if (next_block && next_block < end)
1637 end = next_block - 1;
1639 glob = strnchr(iter, end - iter, '*');
1641 cmplen = glob - iter;
1643 cmplen = max_t(size_t, len, (end - iter));
1645 if (!strncmp(name, iter, cmplen)) {
1646 flags |= block_flags;
1650 if (!*end || *end == ';')
1656 return flags | slub_debug_local;
1658 #else /* !CONFIG_SLUB_DEBUG */
1659 static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
1661 void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
1663 static inline int alloc_debug_processing(struct kmem_cache *s,
1664 struct slab *slab, void *object, unsigned long addr) { return 0; }
1666 static inline int free_debug_processing(
1667 struct kmem_cache *s, struct slab *slab,
1668 void *head, void *tail, int bulk_cnt,
1669 unsigned long addr) { return 0; }
1671 static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
1672 static inline int check_object(struct kmem_cache *s, struct slab *slab,
1673 void *object, u8 val) { return 1; }
1674 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1675 struct slab *slab) {}
1676 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1677 struct slab *slab) {}
1678 slab_flags_t kmem_cache_flags(unsigned int object_size,
1679 slab_flags_t flags, const char *name)
1683 #define slub_debug 0
1685 #define disable_higher_order_debug 0
1687 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1689 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1691 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1693 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1696 static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1697 void **freelist, void *nextfree)
1701 #endif /* CONFIG_SLUB_DEBUG */
1704 * Hooks for other subsystems that check memory allocations. In a typical
1705 * production configuration these hooks all should produce no code at all.
1707 static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1709 ptr = kasan_kmalloc_large(ptr, size, flags);
1710 /* As ptr might get tagged, call kmemleak hook after KASAN. */
1711 kmemleak_alloc(ptr, size, 1, flags);
1715 static __always_inline void kfree_hook(void *x)
1718 kasan_kfree_large(x);
1721 static __always_inline bool slab_free_hook(struct kmem_cache *s,
1724 kmemleak_free_recursive(x, s->flags);
1726 debug_check_no_locks_freed(x, s->object_size);
1728 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1729 debug_check_no_obj_freed(x, s->object_size);
1731 /* Use KCSAN to help debug racy use-after-free. */
1732 if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
1733 __kcsan_check_access(x, s->object_size,
1734 KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
1737 * As memory initialization might be integrated into KASAN,
1738 * kasan_slab_free and initialization memset's must be
1739 * kept together to avoid discrepancies in behavior.
1741 * The initialization memset's clear the object and the metadata,
1742 * but don't touch the SLAB redzone.
1747 if (!kasan_has_integrated_init())
1748 memset(kasan_reset_tag(x), 0, s->object_size);
1749 rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
1750 memset((char *)kasan_reset_tag(x) + s->inuse, 0,
1751 s->size - s->inuse - rsize);
1753 /* KASAN might put x into memory quarantine, delaying its reuse. */
1754 return kasan_slab_free(s, x, init);
1757 static inline bool slab_free_freelist_hook(struct kmem_cache *s,
1758 void **head, void **tail,
1764 void *old_tail = *tail ? *tail : *head;
1766 if (is_kfence_address(next)) {
1767 slab_free_hook(s, next, false);
1771 /* Head and tail of the reconstructed freelist */
1777 next = get_freepointer(s, object);
1779 /* If object's reuse doesn't have to be delayed */
1780 if (!slab_free_hook(s, object, slab_want_init_on_free(s))) {
1781 /* Move object to the new freelist */
1782 set_freepointer(s, object, *head);
1788 * Adjust the reconstructed freelist depth
1789 * accordingly if object's reuse is delayed.
1793 } while (object != old_tail);
1798 return *head != NULL;
1801 static void *setup_object(struct kmem_cache *s, void *object)
1803 setup_object_debug(s, object);
1804 object = kasan_init_slab_obj(s, object);
1805 if (unlikely(s->ctor)) {
1806 kasan_unpoison_object_data(s, object);
1808 kasan_poison_object_data(s, object);
1814 * Slab allocation and freeing
1816 static inline struct slab *alloc_slab_page(gfp_t flags, int node,
1817 struct kmem_cache_order_objects oo)
1819 struct folio *folio;
1821 unsigned int order = oo_order(oo);
1823 if (node == NUMA_NO_NODE)
1824 folio = (struct folio *)alloc_pages(flags, order);
1826 folio = (struct folio *)__alloc_pages_node(node, flags, order);
1831 slab = folio_slab(folio);
1832 __folio_set_slab(folio);
1833 if (page_is_pfmemalloc(folio_page(folio, 0)))
1834 slab_set_pfmemalloc(slab);
1839 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1840 /* Pre-initialize the random sequence cache */
1841 static int init_cache_random_seq(struct kmem_cache *s)
1843 unsigned int count = oo_objects(s->oo);
1846 /* Bailout if already initialised */
1850 err = cache_random_seq_create(s, count, GFP_KERNEL);
1852 pr_err("SLUB: Unable to initialize free list for %s\n",
1857 /* Transform to an offset on the set of pages */
1858 if (s->random_seq) {
1861 for (i = 0; i < count; i++)
1862 s->random_seq[i] *= s->size;
1867 /* Initialize each random sequence freelist per cache */
1868 static void __init init_freelist_randomization(void)
1870 struct kmem_cache *s;
1872 mutex_lock(&slab_mutex);
1874 list_for_each_entry(s, &slab_caches, list)
1875 init_cache_random_seq(s);
1877 mutex_unlock(&slab_mutex);
1880 /* Get the next entry on the pre-computed freelist randomized */
1881 static void *next_freelist_entry(struct kmem_cache *s, struct slab *slab,
1882 unsigned long *pos, void *start,
1883 unsigned long page_limit,
1884 unsigned long freelist_count)
1889 * If the target page allocation failed, the number of objects on the
1890 * page might be smaller than the usual size defined by the cache.
1893 idx = s->random_seq[*pos];
1895 if (*pos >= freelist_count)
1897 } while (unlikely(idx >= page_limit));
1899 return (char *)start + idx;
1902 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1903 static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
1908 unsigned long idx, pos, page_limit, freelist_count;
1910 if (slab->objects < 2 || !s->random_seq)
1913 freelist_count = oo_objects(s->oo);
1914 pos = get_random_int() % freelist_count;
1916 page_limit = slab->objects * s->size;
1917 start = fixup_red_left(s, slab_address(slab));
1919 /* First entry is used as the base of the freelist */
1920 cur = next_freelist_entry(s, slab, &pos, start, page_limit,
1922 cur = setup_object(s, cur);
1923 slab->freelist = cur;
1925 for (idx = 1; idx < slab->objects; idx++) {
1926 next = next_freelist_entry(s, slab, &pos, start, page_limit,
1928 next = setup_object(s, next);
1929 set_freepointer(s, cur, next);
1932 set_freepointer(s, cur, NULL);
1937 static inline int init_cache_random_seq(struct kmem_cache *s)
1941 static inline void init_freelist_randomization(void) { }
1942 static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
1946 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1948 static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1951 struct kmem_cache_order_objects oo = s->oo;
1953 void *start, *p, *next;
1957 flags &= gfp_allowed_mask;
1959 flags |= s->allocflags;
1962 * Let the initial higher-order allocation fail under memory pressure
1963 * so we fall-back to the minimum order allocation.
1965 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1966 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1967 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
1969 slab = alloc_slab_page(alloc_gfp, node, oo);
1970 if (unlikely(!slab)) {
1974 * Allocation may have failed due to fragmentation.
1975 * Try a lower order alloc if possible
1977 slab = alloc_slab_page(alloc_gfp, node, oo);
1978 if (unlikely(!slab))
1980 stat(s, ORDER_FALLBACK);
1983 slab->objects = oo_objects(oo);
1985 account_slab(slab, oo_order(oo), s, flags);
1987 slab->slab_cache = s;
1989 kasan_poison_slab(slab);
1991 start = slab_address(slab);
1993 setup_slab_debug(s, slab, start);
1995 shuffle = shuffle_freelist(s, slab);
1998 start = fixup_red_left(s, start);
1999 start = setup_object(s, start);
2000 slab->freelist = start;
2001 for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
2003 next = setup_object(s, next);
2004 set_freepointer(s, p, next);
2007 set_freepointer(s, p, NULL);
2010 slab->inuse = slab->objects;
2017 inc_slabs_node(s, slab_nid(slab), slab->objects);
2022 static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
2024 if (unlikely(flags & GFP_SLAB_BUG_MASK))
2025 flags = kmalloc_fix_flags(flags);
2027 WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2029 return allocate_slab(s,
2030 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
2033 static void __free_slab(struct kmem_cache *s, struct slab *slab)
2035 struct folio *folio = slab_folio(slab);
2036 int order = folio_order(folio);
2037 int pages = 1 << order;
2039 if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
2042 slab_pad_check(s, slab);
2043 for_each_object(p, s, slab_address(slab), slab->objects)
2044 check_object(s, slab, p, SLUB_RED_INACTIVE);
2047 __slab_clear_pfmemalloc(slab);
2048 __folio_clear_slab(folio);
2049 folio->mapping = NULL;
2050 if (current->reclaim_state)
2051 current->reclaim_state->reclaimed_slab += pages;
2052 unaccount_slab(slab, order, s);
2053 __free_pages(folio_page(folio, 0), order);
2056 static void rcu_free_slab(struct rcu_head *h)
2058 struct slab *slab = container_of(h, struct slab, rcu_head);
2060 __free_slab(slab->slab_cache, slab);
2063 static void free_slab(struct kmem_cache *s, struct slab *slab)
2065 if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
2066 call_rcu(&slab->rcu_head, rcu_free_slab);
2068 __free_slab(s, slab);
2071 static void discard_slab(struct kmem_cache *s, struct slab *slab)
2073 dec_slabs_node(s, slab_nid(slab), slab->objects);
2078 * Management of partially allocated slabs.
2081 __add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
2084 if (tail == DEACTIVATE_TO_TAIL)
2085 list_add_tail(&slab->slab_list, &n->partial);
2087 list_add(&slab->slab_list, &n->partial);
2090 static inline void add_partial(struct kmem_cache_node *n,
2091 struct slab *slab, int tail)
2093 lockdep_assert_held(&n->list_lock);
2094 __add_partial(n, slab, tail);
2097 static inline void remove_partial(struct kmem_cache_node *n,
2100 lockdep_assert_held(&n->list_lock);
2101 list_del(&slab->slab_list);
2106 * Remove slab from the partial list, freeze it and
2107 * return the pointer to the freelist.
2109 * Returns a list of objects or NULL if it fails.
2111 static inline void *acquire_slab(struct kmem_cache *s,
2112 struct kmem_cache_node *n, struct slab *slab,
2116 unsigned long counters;
2119 lockdep_assert_held(&n->list_lock);
2122 * Zap the freelist and set the frozen bit.
2123 * The old freelist is the list of objects for the
2124 * per cpu allocation list.
2126 freelist = slab->freelist;
2127 counters = slab->counters;
2128 new.counters = counters;
2130 new.inuse = slab->objects;
2131 new.freelist = NULL;
2133 new.freelist = freelist;
2136 VM_BUG_ON(new.frozen);
2139 if (!__cmpxchg_double_slab(s, slab,
2141 new.freelist, new.counters,
2145 remove_partial(n, slab);
2150 #ifdef CONFIG_SLUB_CPU_PARTIAL
2151 static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
2153 static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
2156 static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
2159 * Try to allocate a partial slab from a specific node.
2161 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
2162 struct slab **ret_slab, gfp_t gfpflags)
2164 struct slab *slab, *slab2;
2165 void *object = NULL;
2166 unsigned long flags;
2167 unsigned int partial_slabs = 0;
2170 * Racy check. If we mistakenly see no partial slabs then we
2171 * just allocate an empty slab. If we mistakenly try to get a
2172 * partial slab and there is none available then get_partial()
2175 if (!n || !n->nr_partial)
2178 spin_lock_irqsave(&n->list_lock, flags);
2179 list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
2182 if (!pfmemalloc_match(slab, gfpflags))
2185 t = acquire_slab(s, n, slab, object == NULL);
2191 stat(s, ALLOC_FROM_PARTIAL);
2194 put_cpu_partial(s, slab, 0);
2195 stat(s, CPU_PARTIAL_NODE);
2198 #ifdef CONFIG_SLUB_CPU_PARTIAL
2199 if (!kmem_cache_has_cpu_partial(s)
2200 || partial_slabs > s->cpu_partial_slabs / 2)
2207 spin_unlock_irqrestore(&n->list_lock, flags);
2212 * Get a slab from somewhere. Search in increasing NUMA distances.
2214 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
2215 struct slab **ret_slab)
2218 struct zonelist *zonelist;
2221 enum zone_type highest_zoneidx = gfp_zone(flags);
2223 unsigned int cpuset_mems_cookie;
2226 * The defrag ratio allows a configuration of the tradeoffs between
2227 * inter node defragmentation and node local allocations. A lower
2228 * defrag_ratio increases the tendency to do local allocations
2229 * instead of attempting to obtain partial slabs from other nodes.
2231 * If the defrag_ratio is set to 0 then kmalloc() always
2232 * returns node local objects. If the ratio is higher then kmalloc()
2233 * may return off node objects because partial slabs are obtained
2234 * from other nodes and filled up.
2236 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2237 * (which makes defrag_ratio = 1000) then every (well almost)
2238 * allocation will first attempt to defrag slab caches on other nodes.
2239 * This means scanning over all nodes to look for partial slabs which
2240 * may be expensive if we do it every time we are trying to find a slab
2241 * with available objects.
2243 if (!s->remote_node_defrag_ratio ||
2244 get_cycles() % 1024 > s->remote_node_defrag_ratio)
2248 cpuset_mems_cookie = read_mems_allowed_begin();
2249 zonelist = node_zonelist(mempolicy_slab_node(), flags);
2250 for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
2251 struct kmem_cache_node *n;
2253 n = get_node(s, zone_to_nid(zone));
2255 if (n && cpuset_zone_allowed(zone, flags) &&
2256 n->nr_partial > s->min_partial) {
2257 object = get_partial_node(s, n, ret_slab, flags);
2260 * Don't check read_mems_allowed_retry()
2261 * here - if mems_allowed was updated in
2262 * parallel, that was a harmless race
2263 * between allocation and the cpuset
2270 } while (read_mems_allowed_retry(cpuset_mems_cookie));
2271 #endif /* CONFIG_NUMA */
2276 * Get a partial slab, lock it and return it.
2278 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
2279 struct slab **ret_slab)
2282 int searchnode = node;
2284 if (node == NUMA_NO_NODE)
2285 searchnode = numa_mem_id();
2287 object = get_partial_node(s, get_node(s, searchnode), ret_slab, flags);
2288 if (object || node != NUMA_NO_NODE)
2291 return get_any_partial(s, flags, ret_slab);
2294 #ifdef CONFIG_PREEMPTION
2296 * Calculate the next globally unique transaction for disambiguation
2297 * during cmpxchg. The transactions start with the cpu number and are then
2298 * incremented by CONFIG_NR_CPUS.
2300 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
2303 * No preemption supported therefore also no need to check for
2309 static inline unsigned long next_tid(unsigned long tid)
2311 return tid + TID_STEP;
2314 #ifdef SLUB_DEBUG_CMPXCHG
2315 static inline unsigned int tid_to_cpu(unsigned long tid)
2317 return tid % TID_STEP;
2320 static inline unsigned long tid_to_event(unsigned long tid)
2322 return tid / TID_STEP;
2326 static inline unsigned int init_tid(int cpu)
2331 static inline void note_cmpxchg_failure(const char *n,
2332 const struct kmem_cache *s, unsigned long tid)
2334 #ifdef SLUB_DEBUG_CMPXCHG
2335 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2337 pr_info("%s %s: cmpxchg redo ", n, s->name);
2339 #ifdef CONFIG_PREEMPTION
2340 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2341 pr_warn("due to cpu change %d -> %d\n",
2342 tid_to_cpu(tid), tid_to_cpu(actual_tid));
2345 if (tid_to_event(tid) != tid_to_event(actual_tid))
2346 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2347 tid_to_event(tid), tid_to_event(actual_tid));
2349 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2350 actual_tid, tid, next_tid(tid));
2352 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2355 static void init_kmem_cache_cpus(struct kmem_cache *s)
2358 struct kmem_cache_cpu *c;
2360 for_each_possible_cpu(cpu) {
2361 c = per_cpu_ptr(s->cpu_slab, cpu);
2362 local_lock_init(&c->lock);
2363 c->tid = init_tid(cpu);
2368 * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
2369 * unfreezes the slabs and puts it on the proper list.
2370 * Assumes the slab has been already safely taken away from kmem_cache_cpu
2373 static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
2376 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE, M_FULL_NOLIST };
2377 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
2379 enum slab_modes mode = M_NONE;
2380 void *nextfree, *freelist_iter, *freelist_tail;
2381 int tail = DEACTIVATE_TO_HEAD;
2382 unsigned long flags = 0;
2386 if (slab->freelist) {
2387 stat(s, DEACTIVATE_REMOTE_FREES);
2388 tail = DEACTIVATE_TO_TAIL;
2392 * Stage one: Count the objects on cpu's freelist as free_delta and
2393 * remember the last object in freelist_tail for later splicing.
2395 freelist_tail = NULL;
2396 freelist_iter = freelist;
2397 while (freelist_iter) {
2398 nextfree = get_freepointer(s, freelist_iter);
2401 * If 'nextfree' is invalid, it is possible that the object at
2402 * 'freelist_iter' is already corrupted. So isolate all objects
2403 * starting at 'freelist_iter' by skipping them.
2405 if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
2408 freelist_tail = freelist_iter;
2411 freelist_iter = nextfree;
2415 * Stage two: Unfreeze the slab while splicing the per-cpu
2416 * freelist to the head of slab's freelist.
2418 * Ensure that the slab is unfrozen while the list presence
2419 * reflects the actual number of objects during unfreeze.
2421 * We first perform cmpxchg holding lock and insert to list
2422 * when it succeed. If there is mismatch then the slab is not
2423 * unfrozen and number of objects in the slab may have changed.
2424 * Then release lock and retry cmpxchg again.
2428 old.freelist = READ_ONCE(slab->freelist);
2429 old.counters = READ_ONCE(slab->counters);
2430 VM_BUG_ON(!old.frozen);
2432 /* Determine target state of the slab */
2433 new.counters = old.counters;
2434 if (freelist_tail) {
2435 new.inuse -= free_delta;
2436 set_freepointer(s, freelist_tail, old.freelist);
2437 new.freelist = freelist;
2439 new.freelist = old.freelist;
2443 if (!new.inuse && n->nr_partial >= s->min_partial) {
2445 } else if (new.freelist) {
2448 * Taking the spinlock removes the possibility that
2449 * acquire_slab() will see a slab that is frozen
2451 spin_lock_irqsave(&n->list_lock, flags);
2452 } else if (kmem_cache_debug_flags(s, SLAB_STORE_USER)) {
2455 * This also ensures that the scanning of full
2456 * slabs from diagnostic functions will not see
2459 spin_lock_irqsave(&n->list_lock, flags);
2461 mode = M_FULL_NOLIST;
2465 if (!cmpxchg_double_slab(s, slab,
2466 old.freelist, old.counters,
2467 new.freelist, new.counters,
2468 "unfreezing slab")) {
2469 if (mode == M_PARTIAL || mode == M_FULL)
2470 spin_unlock_irqrestore(&n->list_lock, flags);
2475 if (mode == M_PARTIAL) {
2476 add_partial(n, slab, tail);
2477 spin_unlock_irqrestore(&n->list_lock, flags);
2479 } else if (mode == M_FREE) {
2480 stat(s, DEACTIVATE_EMPTY);
2481 discard_slab(s, slab);
2483 } else if (mode == M_FULL) {
2484 add_full(s, n, slab);
2485 spin_unlock_irqrestore(&n->list_lock, flags);
2486 stat(s, DEACTIVATE_FULL);
2487 } else if (mode == M_FULL_NOLIST) {
2488 stat(s, DEACTIVATE_FULL);
2492 #ifdef CONFIG_SLUB_CPU_PARTIAL
2493 static void __unfreeze_partials(struct kmem_cache *s, struct slab *partial_slab)
2495 struct kmem_cache_node *n = NULL, *n2 = NULL;
2496 struct slab *slab, *slab_to_discard = NULL;
2497 unsigned long flags = 0;
2499 while (partial_slab) {
2503 slab = partial_slab;
2504 partial_slab = slab->next;
2506 n2 = get_node(s, slab_nid(slab));
2509 spin_unlock_irqrestore(&n->list_lock, flags);
2512 spin_lock_irqsave(&n->list_lock, flags);
2517 old.freelist = slab->freelist;
2518 old.counters = slab->counters;
2519 VM_BUG_ON(!old.frozen);
2521 new.counters = old.counters;
2522 new.freelist = old.freelist;
2526 } while (!__cmpxchg_double_slab(s, slab,
2527 old.freelist, old.counters,
2528 new.freelist, new.counters,
2529 "unfreezing slab"));
2531 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2532 slab->next = slab_to_discard;
2533 slab_to_discard = slab;
2535 add_partial(n, slab, DEACTIVATE_TO_TAIL);
2536 stat(s, FREE_ADD_PARTIAL);
2541 spin_unlock_irqrestore(&n->list_lock, flags);
2543 while (slab_to_discard) {
2544 slab = slab_to_discard;
2545 slab_to_discard = slab_to_discard->next;
2547 stat(s, DEACTIVATE_EMPTY);
2548 discard_slab(s, slab);
2554 * Unfreeze all the cpu partial slabs.
2556 static void unfreeze_partials(struct kmem_cache *s)
2558 struct slab *partial_slab;
2559 unsigned long flags;
2561 local_lock_irqsave(&s->cpu_slab->lock, flags);
2562 partial_slab = this_cpu_read(s->cpu_slab->partial);
2563 this_cpu_write(s->cpu_slab->partial, NULL);
2564 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2567 __unfreeze_partials(s, partial_slab);
2570 static void unfreeze_partials_cpu(struct kmem_cache *s,
2571 struct kmem_cache_cpu *c)
2573 struct slab *partial_slab;
2575 partial_slab = slub_percpu_partial(c);
2579 __unfreeze_partials(s, partial_slab);
2583 * Put a slab that was just frozen (in __slab_free|get_partial_node) into a
2584 * partial slab slot if available.
2586 * If we did not find a slot then simply move all the partials to the
2587 * per node partial list.
2589 static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
2591 struct slab *oldslab;
2592 struct slab *slab_to_unfreeze = NULL;
2593 unsigned long flags;
2596 local_lock_irqsave(&s->cpu_slab->lock, flags);
2598 oldslab = this_cpu_read(s->cpu_slab->partial);
2601 if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
2603 * Partial array is full. Move the existing set to the
2604 * per node partial list. Postpone the actual unfreezing
2605 * outside of the critical section.
2607 slab_to_unfreeze = oldslab;
2610 slabs = oldslab->slabs;
2616 slab->slabs = slabs;
2617 slab->next = oldslab;
2619 this_cpu_write(s->cpu_slab->partial, slab);
2621 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2623 if (slab_to_unfreeze) {
2624 __unfreeze_partials(s, slab_to_unfreeze);
2625 stat(s, CPU_PARTIAL_DRAIN);
2629 #else /* CONFIG_SLUB_CPU_PARTIAL */
2631 static inline void unfreeze_partials(struct kmem_cache *s) { }
2632 static inline void unfreeze_partials_cpu(struct kmem_cache *s,
2633 struct kmem_cache_cpu *c) { }
2635 #endif /* CONFIG_SLUB_CPU_PARTIAL */
2637 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2639 unsigned long flags;
2643 local_lock_irqsave(&s->cpu_slab->lock, flags);
2646 freelist = c->freelist;
2650 c->tid = next_tid(c->tid);
2652 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2655 deactivate_slab(s, slab, freelist);
2656 stat(s, CPUSLAB_FLUSH);
2660 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2662 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2663 void *freelist = c->freelist;
2664 struct slab *slab = c->slab;
2668 c->tid = next_tid(c->tid);
2671 deactivate_slab(s, slab, freelist);
2672 stat(s, CPUSLAB_FLUSH);
2675 unfreeze_partials_cpu(s, c);
2678 struct slub_flush_work {
2679 struct work_struct work;
2680 struct kmem_cache *s;
2687 * Called from CPU work handler with migration disabled.
2689 static void flush_cpu_slab(struct work_struct *w)
2691 struct kmem_cache *s;
2692 struct kmem_cache_cpu *c;
2693 struct slub_flush_work *sfw;
2695 sfw = container_of(w, struct slub_flush_work, work);
2698 c = this_cpu_ptr(s->cpu_slab);
2703 unfreeze_partials(s);
2706 static bool has_cpu_slab(int cpu, struct kmem_cache *s)
2708 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2710 return c->slab || slub_percpu_partial(c);
2713 static DEFINE_MUTEX(flush_lock);
2714 static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
2716 static void flush_all_cpus_locked(struct kmem_cache *s)
2718 struct slub_flush_work *sfw;
2721 lockdep_assert_cpus_held();
2722 mutex_lock(&flush_lock);
2724 for_each_online_cpu(cpu) {
2725 sfw = &per_cpu(slub_flush, cpu);
2726 if (!has_cpu_slab(cpu, s)) {
2730 INIT_WORK(&sfw->work, flush_cpu_slab);
2733 schedule_work_on(cpu, &sfw->work);
2736 for_each_online_cpu(cpu) {
2737 sfw = &per_cpu(slub_flush, cpu);
2740 flush_work(&sfw->work);
2743 mutex_unlock(&flush_lock);
2746 static void flush_all(struct kmem_cache *s)
2749 flush_all_cpus_locked(s);
2754 * Use the cpu notifier to insure that the cpu slabs are flushed when
2757 static int slub_cpu_dead(unsigned int cpu)
2759 struct kmem_cache *s;
2761 mutex_lock(&slab_mutex);
2762 list_for_each_entry(s, &slab_caches, list)
2763 __flush_cpu_slab(s, cpu);
2764 mutex_unlock(&slab_mutex);
2769 * Check if the objects in a per cpu structure fit numa
2770 * locality expectations.
2772 static inline int node_match(struct slab *slab, int node)
2775 if (node != NUMA_NO_NODE && slab_nid(slab) != node)
2781 #ifdef CONFIG_SLUB_DEBUG
2782 static int count_free(struct slab *slab)
2784 return slab->objects - slab->inuse;
2787 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2789 return atomic_long_read(&n->total_objects);
2791 #endif /* CONFIG_SLUB_DEBUG */
2793 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2794 static unsigned long count_partial(struct kmem_cache_node *n,
2795 int (*get_count)(struct slab *))
2797 unsigned long flags;
2798 unsigned long x = 0;
2801 spin_lock_irqsave(&n->list_lock, flags);
2802 list_for_each_entry(slab, &n->partial, slab_list)
2803 x += get_count(slab);
2804 spin_unlock_irqrestore(&n->list_lock, flags);
2807 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2809 static noinline void
2810 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2812 #ifdef CONFIG_SLUB_DEBUG
2813 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2814 DEFAULT_RATELIMIT_BURST);
2816 struct kmem_cache_node *n;
2818 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2821 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2822 nid, gfpflags, &gfpflags);
2823 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2824 s->name, s->object_size, s->size, oo_order(s->oo),
2827 if (oo_order(s->min) > get_order(s->object_size))
2828 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2831 for_each_kmem_cache_node(s, node, n) {
2832 unsigned long nr_slabs;
2833 unsigned long nr_objs;
2834 unsigned long nr_free;
2836 nr_free = count_partial(n, count_free);
2837 nr_slabs = node_nr_slabs(n);
2838 nr_objs = node_nr_objs(n);
2840 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2841 node, nr_slabs, nr_objs, nr_free);
2846 static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
2848 if (unlikely(slab_test_pfmemalloc(slab)))
2849 return gfp_pfmemalloc_allowed(gfpflags);
2855 * Check the slab->freelist and either transfer the freelist to the
2856 * per cpu freelist or deactivate the slab.
2858 * The slab is still frozen if the return value is not NULL.
2860 * If this function returns NULL then the slab has been unfrozen.
2862 static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
2865 unsigned long counters;
2868 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
2871 freelist = slab->freelist;
2872 counters = slab->counters;
2874 new.counters = counters;
2875 VM_BUG_ON(!new.frozen);
2877 new.inuse = slab->objects;
2878 new.frozen = freelist != NULL;
2880 } while (!__cmpxchg_double_slab(s, slab,
2889 * Slow path. The lockless freelist is empty or we need to perform
2892 * Processing is still very fast if new objects have been freed to the
2893 * regular freelist. In that case we simply take over the regular freelist
2894 * as the lockless freelist and zap the regular freelist.
2896 * If that is not working then we fall back to the partial lists. We take the
2897 * first element of the freelist as the object to allocate now and move the
2898 * rest of the freelist to the lockless freelist.
2900 * And if we were unable to get a new slab from the partial slab lists then
2901 * we need to allocate a new slab. This is the slowest path since it involves
2902 * a call to the page allocator and the setup of a new slab.
2904 * Version of __slab_alloc to use when we know that preemption is
2905 * already disabled (which is the case for bulk allocation).
2907 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2908 unsigned long addr, struct kmem_cache_cpu *c)
2912 unsigned long flags;
2914 stat(s, ALLOC_SLOWPATH);
2918 slab = READ_ONCE(c->slab);
2921 * if the node is not online or has no normal memory, just
2922 * ignore the node constraint
2924 if (unlikely(node != NUMA_NO_NODE &&
2925 !node_isset(node, slab_nodes)))
2926 node = NUMA_NO_NODE;
2931 if (unlikely(!node_match(slab, node))) {
2933 * same as above but node_match() being false already
2934 * implies node != NUMA_NO_NODE
2936 if (!node_isset(node, slab_nodes)) {
2937 node = NUMA_NO_NODE;
2939 stat(s, ALLOC_NODE_MISMATCH);
2940 goto deactivate_slab;
2945 * By rights, we should be searching for a slab page that was
2946 * PFMEMALLOC but right now, we are losing the pfmemalloc
2947 * information when the page leaves the per-cpu allocator
2949 if (unlikely(!pfmemalloc_match(slab, gfpflags)))
2950 goto deactivate_slab;
2952 /* must check again c->slab in case we got preempted and it changed */
2953 local_lock_irqsave(&s->cpu_slab->lock, flags);
2954 if (unlikely(slab != c->slab)) {
2955 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2958 freelist = c->freelist;
2962 freelist = get_freelist(s, slab);
2966 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2967 stat(s, DEACTIVATE_BYPASS);
2971 stat(s, ALLOC_REFILL);
2975 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
2978 * freelist is pointing to the list of objects to be used.
2979 * slab is pointing to the slab from which the objects are obtained.
2980 * That slab must be frozen for per cpu allocations to work.
2982 VM_BUG_ON(!c->slab->frozen);
2983 c->freelist = get_freepointer(s, freelist);
2984 c->tid = next_tid(c->tid);
2985 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2990 local_lock_irqsave(&s->cpu_slab->lock, flags);
2991 if (slab != c->slab) {
2992 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2995 freelist = c->freelist;
2998 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2999 deactivate_slab(s, slab, freelist);
3003 if (slub_percpu_partial(c)) {
3004 local_lock_irqsave(&s->cpu_slab->lock, flags);
3005 if (unlikely(c->slab)) {
3006 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3009 if (unlikely(!slub_percpu_partial(c))) {
3010 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3011 /* we were preempted and partial list got empty */
3015 slab = c->slab = slub_percpu_partial(c);
3016 slub_set_percpu_partial(c, slab);
3017 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3018 stat(s, CPU_PARTIAL_ALLOC);
3024 freelist = get_partial(s, gfpflags, node, &slab);
3026 goto check_new_slab;
3028 slub_put_cpu_ptr(s->cpu_slab);
3029 slab = new_slab(s, gfpflags, node);
3030 c = slub_get_cpu_ptr(s->cpu_slab);
3032 if (unlikely(!slab)) {
3033 slab_out_of_memory(s, gfpflags, node);
3038 * No other reference to the slab yet so we can
3039 * muck around with it freely without cmpxchg
3041 freelist = slab->freelist;
3042 slab->freelist = NULL;
3044 stat(s, ALLOC_SLAB);
3048 if (kmem_cache_debug(s)) {
3049 if (!alloc_debug_processing(s, slab, freelist, addr)) {
3050 /* Slab failed checks. Next slab needed */
3054 * For debug case, we don't load freelist so that all
3055 * allocations go through alloc_debug_processing()
3061 if (unlikely(!pfmemalloc_match(slab, gfpflags)))
3063 * For !pfmemalloc_match() case we don't load freelist so that
3064 * we don't make further mismatched allocations easier.
3070 local_lock_irqsave(&s->cpu_slab->lock, flags);
3071 if (unlikely(c->slab)) {
3072 void *flush_freelist = c->freelist;
3073 struct slab *flush_slab = c->slab;
3077 c->tid = next_tid(c->tid);
3079 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3081 deactivate_slab(s, flush_slab, flush_freelist);
3083 stat(s, CPUSLAB_FLUSH);
3085 goto retry_load_slab;
3093 deactivate_slab(s, slab, get_freepointer(s, freelist));
3098 * A wrapper for ___slab_alloc() for contexts where preemption is not yet
3099 * disabled. Compensates for possible cpu changes by refetching the per cpu area
3102 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3103 unsigned long addr, struct kmem_cache_cpu *c)
3107 #ifdef CONFIG_PREEMPT_COUNT
3109 * We may have been preempted and rescheduled on a different
3110 * cpu before disabling preemption. Need to reload cpu area
3113 c = slub_get_cpu_ptr(s->cpu_slab);
3116 p = ___slab_alloc(s, gfpflags, node, addr, c);
3117 #ifdef CONFIG_PREEMPT_COUNT
3118 slub_put_cpu_ptr(s->cpu_slab);
3124 * If the object has been wiped upon free, make sure it's fully initialized by
3125 * zeroing out freelist pointer.
3127 static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
3130 if (unlikely(slab_want_init_on_free(s)) && obj)
3131 memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
3136 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
3137 * have the fastpath folded into their functions. So no function call
3138 * overhead for requests that can be satisfied on the fastpath.
3140 * The fastpath works by first checking if the lockless freelist can be used.
3141 * If not then __slab_alloc is called for slow processing.
3143 * Otherwise we can simply pick the next object from the lockless free list.
3145 static __always_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
3146 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3149 struct kmem_cache_cpu *c;
3152 struct obj_cgroup *objcg = NULL;
3155 s = slab_pre_alloc_hook(s, lru, &objcg, 1, gfpflags);
3159 object = kfence_alloc(s, orig_size, gfpflags);
3160 if (unlikely(object))
3165 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
3166 * enabled. We may switch back and forth between cpus while
3167 * reading from one cpu area. That does not matter as long
3168 * as we end up on the original cpu again when doing the cmpxchg.
3170 * We must guarantee that tid and kmem_cache_cpu are retrieved on the
3171 * same cpu. We read first the kmem_cache_cpu pointer and use it to read
3172 * the tid. If we are preempted and switched to another cpu between the
3173 * two reads, it's OK as the two are still associated with the same cpu
3174 * and cmpxchg later will validate the cpu.
3176 c = raw_cpu_ptr(s->cpu_slab);
3177 tid = READ_ONCE(c->tid);
3180 * Irqless object alloc/free algorithm used here depends on sequence
3181 * of fetching cpu_slab's data. tid should be fetched before anything
3182 * on c to guarantee that object and slab associated with previous tid
3183 * won't be used with current tid. If we fetch tid first, object and
3184 * slab could be one associated with next tid and our alloc/free
3185 * request will be failed. In this case, we will retry. So, no problem.
3190 * The transaction ids are globally unique per cpu and per operation on
3191 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
3192 * occurs on the right processor and that there was no operation on the
3193 * linked list in between.
3196 object = c->freelist;
3199 * We cannot use the lockless fastpath on PREEMPT_RT because if a
3200 * slowpath has taken the local_lock_irqsave(), it is not protected
3201 * against a fast path operation in an irq handler. So we need to take
3202 * the slow path which uses local_lock. It is still relatively fast if
3203 * there is a suitable cpu freelist.
3205 if (IS_ENABLED(CONFIG_PREEMPT_RT) ||
3206 unlikely(!object || !slab || !node_match(slab, node))) {
3207 object = __slab_alloc(s, gfpflags, node, addr, c);
3209 void *next_object = get_freepointer_safe(s, object);
3212 * The cmpxchg will only match if there was no additional
3213 * operation and if we are on the right processor.
3215 * The cmpxchg does the following atomically (without lock
3217 * 1. Relocate first pointer to the current per cpu area.
3218 * 2. Verify that tid and freelist have not been changed
3219 * 3. If they were not changed replace tid and freelist
3221 * Since this is without lock semantics the protection is only
3222 * against code executing on this cpu *not* from access by
3225 if (unlikely(!this_cpu_cmpxchg_double(
3226 s->cpu_slab->freelist, s->cpu_slab->tid,
3228 next_object, next_tid(tid)))) {
3230 note_cmpxchg_failure("slab_alloc", s, tid);
3233 prefetch_freepointer(s, next_object);
3234 stat(s, ALLOC_FASTPATH);
3237 maybe_wipe_obj_freeptr(s, object);
3238 init = slab_want_init_on_alloc(gfpflags, s);
3241 slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init);
3246 static __always_inline void *slab_alloc(struct kmem_cache *s, struct list_lru *lru,
3247 gfp_t gfpflags, unsigned long addr, size_t orig_size)
3249 return slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, addr, orig_size);
3252 static __always_inline
3253 void *__kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
3256 void *ret = slab_alloc(s, lru, gfpflags, _RET_IP_, s->object_size);
3258 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
3264 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
3266 return __kmem_cache_alloc_lru(s, NULL, gfpflags);
3268 EXPORT_SYMBOL(kmem_cache_alloc);
3270 void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
3273 return __kmem_cache_alloc_lru(s, lru, gfpflags);
3275 EXPORT_SYMBOL(kmem_cache_alloc_lru);
3277 #ifdef CONFIG_TRACING
3278 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
3280 void *ret = slab_alloc(s, NULL, gfpflags, _RET_IP_, size);
3281 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
3282 ret = kasan_kmalloc(s, ret, size, gfpflags);
3285 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3289 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
3291 void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
3293 trace_kmem_cache_alloc_node(_RET_IP_, ret,
3294 s->object_size, s->size, gfpflags, node);
3298 EXPORT_SYMBOL(kmem_cache_alloc_node);
3300 #ifdef CONFIG_TRACING
3301 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
3303 int node, size_t size)
3305 void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, size);
3307 trace_kmalloc_node(_RET_IP_, ret,
3308 size, s->size, gfpflags, node);
3310 ret = kasan_kmalloc(s, ret, size, gfpflags);
3313 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3315 #endif /* CONFIG_NUMA */
3318 * Slow path handling. This may still be called frequently since objects
3319 * have a longer lifetime than the cpu slabs in most processing loads.
3321 * So we still attempt to reduce cache line usage. Just take the slab
3322 * lock and free the item. If there is no additional partial slab
3323 * handling required then we can return immediately.
3325 static void __slab_free(struct kmem_cache *s, struct slab *slab,
3326 void *head, void *tail, int cnt,
3333 unsigned long counters;
3334 struct kmem_cache_node *n = NULL;
3335 unsigned long flags;
3337 stat(s, FREE_SLOWPATH);
3339 if (kfence_free(head))
3342 if (kmem_cache_debug(s) &&
3343 !free_debug_processing(s, slab, head, tail, cnt, addr))
3348 spin_unlock_irqrestore(&n->list_lock, flags);
3351 prior = slab->freelist;
3352 counters = slab->counters;
3353 set_freepointer(s, tail, prior);
3354 new.counters = counters;
3355 was_frozen = new.frozen;
3357 if ((!new.inuse || !prior) && !was_frozen) {
3359 if (kmem_cache_has_cpu_partial(s) && !prior) {
3362 * Slab was on no list before and will be
3364 * We can defer the list move and instead
3369 } else { /* Needs to be taken off a list */
3371 n = get_node(s, slab_nid(slab));
3373 * Speculatively acquire the list_lock.
3374 * If the cmpxchg does not succeed then we may
3375 * drop the list_lock without any processing.
3377 * Otherwise the list_lock will synchronize with
3378 * other processors updating the list of slabs.
3380 spin_lock_irqsave(&n->list_lock, flags);
3385 } while (!cmpxchg_double_slab(s, slab,
3392 if (likely(was_frozen)) {
3394 * The list lock was not taken therefore no list
3395 * activity can be necessary.
3397 stat(s, FREE_FROZEN);
3398 } else if (new.frozen) {
3400 * If we just froze the slab then put it onto the
3401 * per cpu partial list.
3403 put_cpu_partial(s, slab, 1);
3404 stat(s, CPU_PARTIAL_FREE);
3410 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
3414 * Objects left in the slab. If it was not on the partial list before
3417 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
3418 remove_full(s, n, slab);
3419 add_partial(n, slab, DEACTIVATE_TO_TAIL);
3420 stat(s, FREE_ADD_PARTIAL);
3422 spin_unlock_irqrestore(&n->list_lock, flags);
3428 * Slab on the partial list.
3430 remove_partial(n, slab);
3431 stat(s, FREE_REMOVE_PARTIAL);
3433 /* Slab must be on the full list */
3434 remove_full(s, n, slab);
3437 spin_unlock_irqrestore(&n->list_lock, flags);
3439 discard_slab(s, slab);
3443 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
3444 * can perform fastpath freeing without additional function calls.
3446 * The fastpath is only possible if we are freeing to the current cpu slab
3447 * of this processor. This typically the case if we have just allocated
3450 * If fastpath is not possible then fall back to __slab_free where we deal
3451 * with all sorts of special processing.
3453 * Bulk free of a freelist with several objects (all pointing to the
3454 * same slab) possible by specifying head and tail ptr, plus objects
3455 * count (cnt). Bulk free indicated by tail pointer being set.
3457 static __always_inline void do_slab_free(struct kmem_cache *s,
3458 struct slab *slab, void *head, void *tail,
3459 int cnt, unsigned long addr)
3461 void *tail_obj = tail ? : head;
3462 struct kmem_cache_cpu *c;
3465 /* memcg_slab_free_hook() is already called for bulk free. */
3467 memcg_slab_free_hook(s, &head, 1);
3470 * Determine the currently cpus per cpu slab.
3471 * The cpu may change afterward. However that does not matter since
3472 * data is retrieved via this pointer. If we are on the same cpu
3473 * during the cmpxchg then the free will succeed.
3475 c = raw_cpu_ptr(s->cpu_slab);
3476 tid = READ_ONCE(c->tid);
3478 /* Same with comment on barrier() in slab_alloc_node() */
3481 if (likely(slab == c->slab)) {
3482 #ifndef CONFIG_PREEMPT_RT
3483 void **freelist = READ_ONCE(c->freelist);
3485 set_freepointer(s, tail_obj, freelist);
3487 if (unlikely(!this_cpu_cmpxchg_double(
3488 s->cpu_slab->freelist, s->cpu_slab->tid,
3490 head, next_tid(tid)))) {
3492 note_cmpxchg_failure("slab_free", s, tid);
3495 #else /* CONFIG_PREEMPT_RT */
3497 * We cannot use the lockless fastpath on PREEMPT_RT because if
3498 * a slowpath has taken the local_lock_irqsave(), it is not
3499 * protected against a fast path operation in an irq handler. So
3500 * we need to take the local_lock. We shouldn't simply defer to
3501 * __slab_free() as that wouldn't use the cpu freelist at all.
3505 local_lock(&s->cpu_slab->lock);
3506 c = this_cpu_ptr(s->cpu_slab);
3507 if (unlikely(slab != c->slab)) {
3508 local_unlock(&s->cpu_slab->lock);
3512 freelist = c->freelist;
3514 set_freepointer(s, tail_obj, freelist);
3516 c->tid = next_tid(tid);
3518 local_unlock(&s->cpu_slab->lock);
3520 stat(s, FREE_FASTPATH);
3522 __slab_free(s, slab, head, tail_obj, cnt, addr);
3526 static __always_inline void slab_free(struct kmem_cache *s, struct slab *slab,
3527 void *head, void *tail, int cnt,
3531 * With KASAN enabled slab_free_freelist_hook modifies the freelist
3532 * to remove objects, whose reuse must be delayed.
3534 if (slab_free_freelist_hook(s, &head, &tail, &cnt))
3535 do_slab_free(s, slab, head, tail, cnt, addr);
3538 #ifdef CONFIG_KASAN_GENERIC
3539 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
3541 do_slab_free(cache, virt_to_slab(x), x, NULL, 1, addr);
3545 void kmem_cache_free(struct kmem_cache *s, void *x)
3547 s = cache_from_obj(s, x);
3550 trace_kmem_cache_free(_RET_IP_, x, s->name);
3551 slab_free(s, virt_to_slab(x), x, NULL, 1, _RET_IP_);
3553 EXPORT_SYMBOL(kmem_cache_free);
3555 struct detached_freelist {
3560 struct kmem_cache *s;
3563 static inline void free_large_kmalloc(struct folio *folio, void *object)
3565 unsigned int order = folio_order(folio);
3567 if (WARN_ON_ONCE(order == 0))
3568 pr_warn_once("object pointer: 0x%p\n", object);
3571 mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B,
3572 -(PAGE_SIZE << order));
3573 __free_pages(folio_page(folio, 0), order);
3577 * This function progressively scans the array with free objects (with
3578 * a limited look ahead) and extract objects belonging to the same
3579 * slab. It builds a detached freelist directly within the given
3580 * slab/objects. This can happen without any need for
3581 * synchronization, because the objects are owned by running process.
3582 * The freelist is build up as a single linked list in the objects.
3583 * The idea is, that this detached freelist can then be bulk
3584 * transferred to the real freelist(s), but only requiring a single
3585 * synchronization primitive. Look ahead in the array is limited due
3586 * to performance reasons.
3589 int build_detached_freelist(struct kmem_cache *s, size_t size,
3590 void **p, struct detached_freelist *df)
3592 size_t first_skipped_index = 0;
3595 struct folio *folio;
3598 /* Always re-init detached_freelist */
3603 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3604 } while (!object && size);
3609 folio = virt_to_folio(object);
3611 /* Handle kalloc'ed objects */
3612 if (unlikely(!folio_test_slab(folio))) {
3613 free_large_kmalloc(folio, object);
3614 p[size] = NULL; /* mark object processed */
3617 /* Derive kmem_cache from object */
3618 slab = folio_slab(folio);
3619 df->s = slab->slab_cache;
3621 slab = folio_slab(folio);
3622 df->s = cache_from_obj(s, object); /* Support for memcg */
3625 if (is_kfence_address(object)) {
3626 slab_free_hook(df->s, object, false);
3627 __kfence_free(object);
3628 p[size] = NULL; /* mark object processed */
3632 /* Start new detached freelist */
3634 set_freepointer(df->s, object, NULL);
3636 df->freelist = object;
3637 p[size] = NULL; /* mark object processed */
3643 continue; /* Skip processed objects */
3645 /* df->slab is always set at this point */
3646 if (df->slab == virt_to_slab(object)) {
3647 /* Opportunity build freelist */
3648 set_freepointer(df->s, object, df->freelist);
3649 df->freelist = object;
3651 p[size] = NULL; /* mark object processed */
3656 /* Limit look ahead search */
3660 if (!first_skipped_index)
3661 first_skipped_index = size + 1;
3664 return first_skipped_index;
3667 /* Note that interrupts must be enabled when calling this function. */
3668 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3673 memcg_slab_free_hook(s, p, size);
3675 struct detached_freelist df;
3677 size = build_detached_freelist(s, size, p, &df);
3681 slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt, _RET_IP_);
3682 } while (likely(size));
3684 EXPORT_SYMBOL(kmem_cache_free_bulk);
3686 /* Note that interrupts must be enabled when calling this function. */
3687 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3690 struct kmem_cache_cpu *c;
3692 struct obj_cgroup *objcg = NULL;
3694 /* memcg and kmem_cache debug support */
3695 s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
3699 * Drain objects in the per cpu slab, while disabling local
3700 * IRQs, which protects against PREEMPT and interrupts
3701 * handlers invoking normal fastpath.
3703 c = slub_get_cpu_ptr(s->cpu_slab);
3704 local_lock_irq(&s->cpu_slab->lock);
3706 for (i = 0; i < size; i++) {
3707 void *object = kfence_alloc(s, s->object_size, flags);
3709 if (unlikely(object)) {
3714 object = c->freelist;
3715 if (unlikely(!object)) {
3717 * We may have removed an object from c->freelist using
3718 * the fastpath in the previous iteration; in that case,
3719 * c->tid has not been bumped yet.
3720 * Since ___slab_alloc() may reenable interrupts while
3721 * allocating memory, we should bump c->tid now.
3723 c->tid = next_tid(c->tid);
3725 local_unlock_irq(&s->cpu_slab->lock);
3728 * Invoking slow path likely have side-effect
3729 * of re-populating per CPU c->freelist
3731 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3733 if (unlikely(!p[i]))
3736 c = this_cpu_ptr(s->cpu_slab);
3737 maybe_wipe_obj_freeptr(s, p[i]);
3739 local_lock_irq(&s->cpu_slab->lock);
3741 continue; /* goto for-loop */
3743 c->freelist = get_freepointer(s, object);
3745 maybe_wipe_obj_freeptr(s, p[i]);
3747 c->tid = next_tid(c->tid);
3748 local_unlock_irq(&s->cpu_slab->lock);
3749 slub_put_cpu_ptr(s->cpu_slab);
3752 * memcg and kmem_cache debug support and memory initialization.
3753 * Done outside of the IRQ disabled fastpath loop.
3755 slab_post_alloc_hook(s, objcg, flags, size, p,
3756 slab_want_init_on_alloc(flags, s));
3759 slub_put_cpu_ptr(s->cpu_slab);
3760 slab_post_alloc_hook(s, objcg, flags, i, p, false);
3761 __kmem_cache_free_bulk(s, i, p);
3764 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3768 * Object placement in a slab is made very easy because we always start at
3769 * offset 0. If we tune the size of the object to the alignment then we can
3770 * get the required alignment by putting one properly sized object after
3773 * Notice that the allocation order determines the sizes of the per cpu
3774 * caches. Each processor has always one slab available for allocations.
3775 * Increasing the allocation order reduces the number of times that slabs
3776 * must be moved on and off the partial lists and is therefore a factor in
3781 * Minimum / Maximum order of slab pages. This influences locking overhead
3782 * and slab fragmentation. A higher order reduces the number of partial slabs
3783 * and increases the number of allocations possible without having to
3784 * take the list_lock.
3786 static unsigned int slub_min_order;
3787 static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3788 static unsigned int slub_min_objects;
3791 * Calculate the order of allocation given an slab object size.
3793 * The order of allocation has significant impact on performance and other
3794 * system components. Generally order 0 allocations should be preferred since
3795 * order 0 does not cause fragmentation in the page allocator. Larger objects
3796 * be problematic to put into order 0 slabs because there may be too much
3797 * unused space left. We go to a higher order if more than 1/16th of the slab
3800 * In order to reach satisfactory performance we must ensure that a minimum
3801 * number of objects is in one slab. Otherwise we may generate too much
3802 * activity on the partial lists which requires taking the list_lock. This is
3803 * less a concern for large slabs though which are rarely used.
3805 * slub_max_order specifies the order where we begin to stop considering the
3806 * number of objects in a slab as critical. If we reach slub_max_order then
3807 * we try to keep the page order as low as possible. So we accept more waste
3808 * of space in favor of a small page order.
3810 * Higher order allocations also allow the placement of more objects in a
3811 * slab and thereby reduce object handling overhead. If the user has
3812 * requested a higher minimum order then we start with that one instead of
3813 * the smallest order which will fit the object.
3815 static inline unsigned int calc_slab_order(unsigned int size,
3816 unsigned int min_objects, unsigned int max_order,
3817 unsigned int fract_leftover)
3819 unsigned int min_order = slub_min_order;
3822 if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
3823 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3825 for (order = max(min_order, (unsigned int)get_order(min_objects * size));
3826 order <= max_order; order++) {
3828 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
3831 rem = slab_size % size;
3833 if (rem <= slab_size / fract_leftover)
3840 static inline int calculate_order(unsigned int size)
3843 unsigned int min_objects;
3844 unsigned int max_objects;
3845 unsigned int nr_cpus;
3848 * Attempt to find best configuration for a slab. This
3849 * works by first attempting to generate a layout with
3850 * the best configuration and backing off gradually.
3852 * First we increase the acceptable waste in a slab. Then
3853 * we reduce the minimum objects required in a slab.
3855 min_objects = slub_min_objects;
3858 * Some architectures will only update present cpus when
3859 * onlining them, so don't trust the number if it's just 1. But
3860 * we also don't want to use nr_cpu_ids always, as on some other
3861 * architectures, there can be many possible cpus, but never
3862 * onlined. Here we compromise between trying to avoid too high
3863 * order on systems that appear larger than they are, and too
3864 * low order on systems that appear smaller than they are.
3866 nr_cpus = num_present_cpus();
3868 nr_cpus = nr_cpu_ids;
3869 min_objects = 4 * (fls(nr_cpus) + 1);
3871 max_objects = order_objects(slub_max_order, size);
3872 min_objects = min(min_objects, max_objects);
3874 while (min_objects > 1) {
3875 unsigned int fraction;
3878 while (fraction >= 4) {
3879 order = calc_slab_order(size, min_objects,
3880 slub_max_order, fraction);
3881 if (order <= slub_max_order)
3889 * We were unable to place multiple objects in a slab. Now
3890 * lets see if we can place a single object there.
3892 order = calc_slab_order(size, 1, slub_max_order, 1);
3893 if (order <= slub_max_order)
3897 * Doh this slab cannot be placed using slub_max_order.
3899 order = calc_slab_order(size, 1, MAX_ORDER, 1);
3900 if (order < MAX_ORDER)
3906 init_kmem_cache_node(struct kmem_cache_node *n)
3909 spin_lock_init(&n->list_lock);
3910 INIT_LIST_HEAD(&n->partial);
3911 #ifdef CONFIG_SLUB_DEBUG
3912 atomic_long_set(&n->nr_slabs, 0);
3913 atomic_long_set(&n->total_objects, 0);
3914 INIT_LIST_HEAD(&n->full);
3918 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3920 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3921 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3924 * Must align to double word boundary for the double cmpxchg
3925 * instructions to work; see __pcpu_double_call_return_bool().
3927 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3928 2 * sizeof(void *));
3933 init_kmem_cache_cpus(s);
3938 static struct kmem_cache *kmem_cache_node;
3941 * No kmalloc_node yet so do it by hand. We know that this is the first
3942 * slab on the node for this slabcache. There are no concurrent accesses
3945 * Note that this function only works on the kmem_cache_node
3946 * when allocating for the kmem_cache_node. This is used for bootstrapping
3947 * memory on a fresh node that has no slab structures yet.
3949 static void early_kmem_cache_node_alloc(int node)
3952 struct kmem_cache_node *n;
3954 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3956 slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3959 if (slab_nid(slab) != node) {
3960 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3961 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3966 #ifdef CONFIG_SLUB_DEBUG
3967 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3968 init_tracking(kmem_cache_node, n);
3970 n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
3971 slab->freelist = get_freepointer(kmem_cache_node, n);
3974 kmem_cache_node->node[node] = n;
3975 init_kmem_cache_node(n);
3976 inc_slabs_node(kmem_cache_node, node, slab->objects);
3979 * No locks need to be taken here as it has just been
3980 * initialized and there is no concurrent access.
3982 __add_partial(n, slab, DEACTIVATE_TO_HEAD);
3985 static void free_kmem_cache_nodes(struct kmem_cache *s)
3988 struct kmem_cache_node *n;
3990 for_each_kmem_cache_node(s, node, n) {
3991 s->node[node] = NULL;
3992 kmem_cache_free(kmem_cache_node, n);
3996 void __kmem_cache_release(struct kmem_cache *s)
3998 cache_random_seq_destroy(s);
3999 free_percpu(s->cpu_slab);
4000 free_kmem_cache_nodes(s);
4003 static int init_kmem_cache_nodes(struct kmem_cache *s)
4007 for_each_node_mask(node, slab_nodes) {
4008 struct kmem_cache_node *n;
4010 if (slab_state == DOWN) {
4011 early_kmem_cache_node_alloc(node);
4014 n = kmem_cache_alloc_node(kmem_cache_node,
4018 free_kmem_cache_nodes(s);
4022 init_kmem_cache_node(n);
4028 static void set_cpu_partial(struct kmem_cache *s)
4030 #ifdef CONFIG_SLUB_CPU_PARTIAL
4031 unsigned int nr_objects;
4034 * cpu_partial determined the maximum number of objects kept in the
4035 * per cpu partial lists of a processor.
4037 * Per cpu partial lists mainly contain slabs that just have one
4038 * object freed. If they are used for allocation then they can be
4039 * filled up again with minimal effort. The slab will never hit the
4040 * per node partial lists and therefore no locking will be required.
4042 * For backwards compatibility reasons, this is determined as number
4043 * of objects, even though we now limit maximum number of pages, see
4044 * slub_set_cpu_partial()
4046 if (!kmem_cache_has_cpu_partial(s))
4048 else if (s->size >= PAGE_SIZE)
4050 else if (s->size >= 1024)
4052 else if (s->size >= 256)
4057 slub_set_cpu_partial(s, nr_objects);
4062 * calculate_sizes() determines the order and the distribution of data within
4065 static int calculate_sizes(struct kmem_cache *s)
4067 slab_flags_t flags = s->flags;
4068 unsigned int size = s->object_size;
4072 * Round up object size to the next word boundary. We can only
4073 * place the free pointer at word boundaries and this determines
4074 * the possible location of the free pointer.
4076 size = ALIGN(size, sizeof(void *));
4078 #ifdef CONFIG_SLUB_DEBUG
4080 * Determine if we can poison the object itself. If the user of
4081 * the slab may touch the object after free or before allocation
4082 * then we should never poison the object itself.
4084 if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
4086 s->flags |= __OBJECT_POISON;
4088 s->flags &= ~__OBJECT_POISON;
4092 * If we are Redzoning then check if there is some space between the
4093 * end of the object and the free pointer. If not then add an
4094 * additional word to have some bytes to store Redzone information.
4096 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
4097 size += sizeof(void *);
4101 * With that we have determined the number of bytes in actual use
4102 * by the object and redzoning.
4106 if ((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
4107 ((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) ||
4110 * Relocate free pointer after the object if it is not
4111 * permitted to overwrite the first word of the object on
4114 * This is the case if we do RCU, have a constructor or
4115 * destructor, are poisoning the objects, or are
4116 * redzoning an object smaller than sizeof(void *).
4118 * The assumption that s->offset >= s->inuse means free
4119 * pointer is outside of the object is used in the
4120 * freeptr_outside_object() function. If that is no
4121 * longer true, the function needs to be modified.
4124 size += sizeof(void *);
4127 * Store freelist pointer near middle of object to keep
4128 * it away from the edges of the object to avoid small
4129 * sized over/underflows from neighboring allocations.
4131 s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
4134 #ifdef CONFIG_SLUB_DEBUG
4135 if (flags & SLAB_STORE_USER)
4137 * Need to store information about allocs and frees after
4140 size += 2 * sizeof(struct track);
4143 kasan_cache_create(s, &size, &s->flags);
4144 #ifdef CONFIG_SLUB_DEBUG
4145 if (flags & SLAB_RED_ZONE) {
4147 * Add some empty padding so that we can catch
4148 * overwrites from earlier objects rather than let
4149 * tracking information or the free pointer be
4150 * corrupted if a user writes before the start
4153 size += sizeof(void *);
4155 s->red_left_pad = sizeof(void *);
4156 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
4157 size += s->red_left_pad;
4162 * SLUB stores one object immediately after another beginning from
4163 * offset 0. In order to align the objects we have to simply size
4164 * each object to conform to the alignment.
4166 size = ALIGN(size, s->align);
4168 s->reciprocal_size = reciprocal_value(size);
4169 order = calculate_order(size);
4176 s->allocflags |= __GFP_COMP;
4178 if (s->flags & SLAB_CACHE_DMA)
4179 s->allocflags |= GFP_DMA;
4181 if (s->flags & SLAB_CACHE_DMA32)
4182 s->allocflags |= GFP_DMA32;
4184 if (s->flags & SLAB_RECLAIM_ACCOUNT)
4185 s->allocflags |= __GFP_RECLAIMABLE;
4188 * Determine the number of objects per slab
4190 s->oo = oo_make(order, size);
4191 s->min = oo_make(get_order(size), size);
4193 return !!oo_objects(s->oo);
4196 static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
4198 s->flags = kmem_cache_flags(s->size, flags, s->name);
4199 #ifdef CONFIG_SLAB_FREELIST_HARDENED
4200 s->random = get_random_long();
4203 if (!calculate_sizes(s))
4205 if (disable_higher_order_debug) {
4207 * Disable debugging flags that store metadata if the min slab
4210 if (get_order(s->size) > get_order(s->object_size)) {
4211 s->flags &= ~DEBUG_METADATA_FLAGS;
4213 if (!calculate_sizes(s))
4218 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
4219 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
4220 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
4221 /* Enable fast mode */
4222 s->flags |= __CMPXCHG_DOUBLE;
4226 * The larger the object size is, the more slabs we want on the partial
4227 * list to avoid pounding the page allocator excessively.
4229 s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
4230 s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
4235 s->remote_node_defrag_ratio = 1000;
4238 /* Initialize the pre-computed randomized freelist if slab is up */
4239 if (slab_state >= UP) {
4240 if (init_cache_random_seq(s))
4244 if (!init_kmem_cache_nodes(s))
4247 if (alloc_kmem_cache_cpus(s))
4251 __kmem_cache_release(s);
4255 static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
4258 #ifdef CONFIG_SLUB_DEBUG
4259 void *addr = slab_address(slab);
4260 unsigned long flags;
4264 slab_err(s, slab, text, s->name);
4265 slab_lock(slab, &flags);
4267 map = get_map(s, slab);
4268 for_each_object(p, s, addr, slab->objects) {
4270 if (!test_bit(__obj_to_index(s, addr, p), map)) {
4271 pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
4272 print_tracking(s, p);
4276 slab_unlock(slab, &flags);
4281 * Attempt to free all partial slabs on a node.
4282 * This is called from __kmem_cache_shutdown(). We must take list_lock
4283 * because sysfs file might still access partial list after the shutdowning.
4285 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
4288 struct slab *slab, *h;
4290 BUG_ON(irqs_disabled());
4291 spin_lock_irq(&n->list_lock);
4292 list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
4294 remove_partial(n, slab);
4295 list_add(&slab->slab_list, &discard);
4297 list_slab_objects(s, slab,
4298 "Objects remaining in %s on __kmem_cache_shutdown()");
4301 spin_unlock_irq(&n->list_lock);
4303 list_for_each_entry_safe(slab, h, &discard, slab_list)
4304 discard_slab(s, slab);
4307 bool __kmem_cache_empty(struct kmem_cache *s)
4310 struct kmem_cache_node *n;
4312 for_each_kmem_cache_node(s, node, n)
4313 if (n->nr_partial || slabs_node(s, node))
4319 * Release all resources used by a slab cache.
4321 int __kmem_cache_shutdown(struct kmem_cache *s)
4324 struct kmem_cache_node *n;
4326 flush_all_cpus_locked(s);
4327 /* Attempt to free all objects */
4328 for_each_kmem_cache_node(s, node, n) {
4330 if (n->nr_partial || slabs_node(s, node))
4336 #ifdef CONFIG_PRINTK
4337 void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
4340 int __maybe_unused i;
4344 struct kmem_cache *s = slab->slab_cache;
4345 struct track __maybe_unused *trackp;
4347 kpp->kp_ptr = object;
4348 kpp->kp_slab = slab;
4349 kpp->kp_slab_cache = s;
4350 base = slab_address(slab);
4351 objp0 = kasan_reset_tag(object);
4352 #ifdef CONFIG_SLUB_DEBUG
4353 objp = restore_red_left(s, objp0);
4357 objnr = obj_to_index(s, slab, objp);
4358 kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
4359 objp = base + s->size * objnr;
4360 kpp->kp_objp = objp;
4361 if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
4362 || (objp - base) % s->size) ||
4363 !(s->flags & SLAB_STORE_USER))
4365 #ifdef CONFIG_SLUB_DEBUG
4366 objp = fixup_red_left(s, objp);
4367 trackp = get_track(s, objp, TRACK_ALLOC);
4368 kpp->kp_ret = (void *)trackp->addr;
4369 #ifdef CONFIG_STACKDEPOT
4371 depot_stack_handle_t handle;
4372 unsigned long *entries;
4373 unsigned int nr_entries;
4375 handle = READ_ONCE(trackp->handle);
4377 nr_entries = stack_depot_fetch(handle, &entries);
4378 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
4379 kpp->kp_stack[i] = (void *)entries[i];
4382 trackp = get_track(s, objp, TRACK_FREE);
4383 handle = READ_ONCE(trackp->handle);
4385 nr_entries = stack_depot_fetch(handle, &entries);
4386 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
4387 kpp->kp_free_stack[i] = (void *)entries[i];
4395 /********************************************************************
4397 *******************************************************************/
4399 static int __init setup_slub_min_order(char *str)
4401 get_option(&str, (int *)&slub_min_order);
4406 __setup("slub_min_order=", setup_slub_min_order);
4408 static int __init setup_slub_max_order(char *str)
4410 get_option(&str, (int *)&slub_max_order);
4411 slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
4416 __setup("slub_max_order=", setup_slub_max_order);
4418 static int __init setup_slub_min_objects(char *str)
4420 get_option(&str, (int *)&slub_min_objects);
4425 __setup("slub_min_objects=", setup_slub_min_objects);
4427 void *__kmalloc(size_t size, gfp_t flags)
4429 struct kmem_cache *s;
4432 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4433 return kmalloc_large(size, flags);
4435 s = kmalloc_slab(size, flags);
4437 if (unlikely(ZERO_OR_NULL_PTR(s)))
4440 ret = slab_alloc(s, NULL, flags, _RET_IP_, size);
4442 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
4444 ret = kasan_kmalloc(s, ret, size, flags);
4448 EXPORT_SYMBOL(__kmalloc);
4451 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
4455 unsigned int order = get_order(size);
4457 flags |= __GFP_COMP;
4458 page = alloc_pages_node(node, flags, order);
4460 ptr = page_address(page);
4461 mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
4462 PAGE_SIZE << order);
4465 return kmalloc_large_node_hook(ptr, size, flags);
4468 void *__kmalloc_node(size_t size, gfp_t flags, int node)
4470 struct kmem_cache *s;
4473 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4474 ret = kmalloc_large_node(size, flags, node);
4476 trace_kmalloc_node(_RET_IP_, ret,
4477 size, PAGE_SIZE << get_order(size),
4483 s = kmalloc_slab(size, flags);
4485 if (unlikely(ZERO_OR_NULL_PTR(s)))
4488 ret = slab_alloc_node(s, NULL, flags, node, _RET_IP_, size);
4490 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
4492 ret = kasan_kmalloc(s, ret, size, flags);
4496 EXPORT_SYMBOL(__kmalloc_node);
4497 #endif /* CONFIG_NUMA */
4499 #ifdef CONFIG_HARDENED_USERCOPY
4501 * Rejects incorrectly sized objects and objects that are to be copied
4502 * to/from userspace but do not fall entirely within the containing slab
4503 * cache's usercopy region.
4505 * Returns NULL if check passes, otherwise const char * to name of cache
4506 * to indicate an error.
4508 void __check_heap_object(const void *ptr, unsigned long n,
4509 const struct slab *slab, bool to_user)
4511 struct kmem_cache *s;
4512 unsigned int offset;
4513 bool is_kfence = is_kfence_address(ptr);
4515 ptr = kasan_reset_tag(ptr);
4517 /* Find object and usable object size. */
4518 s = slab->slab_cache;
4520 /* Reject impossible pointers. */
4521 if (ptr < slab_address(slab))
4522 usercopy_abort("SLUB object not in SLUB page?!", NULL,
4525 /* Find offset within object. */
4527 offset = ptr - kfence_object_start(ptr);
4529 offset = (ptr - slab_address(slab)) % s->size;
4531 /* Adjust for redzone and reject if within the redzone. */
4532 if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
4533 if (offset < s->red_left_pad)
4534 usercopy_abort("SLUB object in left red zone",
4535 s->name, to_user, offset, n);
4536 offset -= s->red_left_pad;
4539 /* Allow address range falling entirely within usercopy region. */
4540 if (offset >= s->useroffset &&
4541 offset - s->useroffset <= s->usersize &&
4542 n <= s->useroffset - offset + s->usersize)
4545 usercopy_abort("SLUB object", s->name, to_user, offset, n);
4547 #endif /* CONFIG_HARDENED_USERCOPY */
4549 size_t __ksize(const void *object)
4551 struct folio *folio;
4553 if (unlikely(object == ZERO_SIZE_PTR))
4556 folio = virt_to_folio(object);
4558 if (unlikely(!folio_test_slab(folio)))
4559 return folio_size(folio);
4561 return slab_ksize(folio_slab(folio)->slab_cache);
4563 EXPORT_SYMBOL(__ksize);
4565 void kfree(const void *x)
4567 struct folio *folio;
4569 void *object = (void *)x;
4571 trace_kfree(_RET_IP_, x);
4573 if (unlikely(ZERO_OR_NULL_PTR(x)))
4576 folio = virt_to_folio(x);
4577 if (unlikely(!folio_test_slab(folio))) {
4578 free_large_kmalloc(folio, object);
4581 slab = folio_slab(folio);
4582 slab_free(slab->slab_cache, slab, object, NULL, 1, _RET_IP_);
4584 EXPORT_SYMBOL(kfree);
4586 #define SHRINK_PROMOTE_MAX 32
4589 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
4590 * up most to the head of the partial lists. New allocations will then
4591 * fill those up and thus they can be removed from the partial lists.
4593 * The slabs with the least items are placed last. This results in them
4594 * being allocated from last increasing the chance that the last objects
4595 * are freed in them.
4597 static int __kmem_cache_do_shrink(struct kmem_cache *s)
4601 struct kmem_cache_node *n;
4604 struct list_head discard;
4605 struct list_head promote[SHRINK_PROMOTE_MAX];
4606 unsigned long flags;
4609 for_each_kmem_cache_node(s, node, n) {
4610 INIT_LIST_HEAD(&discard);
4611 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
4612 INIT_LIST_HEAD(promote + i);
4614 spin_lock_irqsave(&n->list_lock, flags);
4617 * Build lists of slabs to discard or promote.
4619 * Note that concurrent frees may occur while we hold the
4620 * list_lock. slab->inuse here is the upper limit.
4622 list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
4623 int free = slab->objects - slab->inuse;
4625 /* Do not reread slab->inuse */
4628 /* We do not keep full slabs on the list */
4631 if (free == slab->objects) {
4632 list_move(&slab->slab_list, &discard);
4634 } else if (free <= SHRINK_PROMOTE_MAX)
4635 list_move(&slab->slab_list, promote + free - 1);
4639 * Promote the slabs filled up most to the head of the
4642 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
4643 list_splice(promote + i, &n->partial);
4645 spin_unlock_irqrestore(&n->list_lock, flags);
4647 /* Release empty slabs */
4648 list_for_each_entry_safe(slab, t, &discard, slab_list)
4649 discard_slab(s, slab);
4651 if (slabs_node(s, node))
4658 int __kmem_cache_shrink(struct kmem_cache *s)
4661 return __kmem_cache_do_shrink(s);
4664 static int slab_mem_going_offline_callback(void *arg)
4666 struct kmem_cache *s;
4668 mutex_lock(&slab_mutex);
4669 list_for_each_entry(s, &slab_caches, list) {
4670 flush_all_cpus_locked(s);
4671 __kmem_cache_do_shrink(s);
4673 mutex_unlock(&slab_mutex);
4678 static void slab_mem_offline_callback(void *arg)
4680 struct memory_notify *marg = arg;
4683 offline_node = marg->status_change_nid_normal;
4686 * If the node still has available memory. we need kmem_cache_node
4689 if (offline_node < 0)
4692 mutex_lock(&slab_mutex);
4693 node_clear(offline_node, slab_nodes);
4695 * We no longer free kmem_cache_node structures here, as it would be
4696 * racy with all get_node() users, and infeasible to protect them with
4699 mutex_unlock(&slab_mutex);
4702 static int slab_mem_going_online_callback(void *arg)
4704 struct kmem_cache_node *n;
4705 struct kmem_cache *s;
4706 struct memory_notify *marg = arg;
4707 int nid = marg->status_change_nid_normal;
4711 * If the node's memory is already available, then kmem_cache_node is
4712 * already created. Nothing to do.
4718 * We are bringing a node online. No memory is available yet. We must
4719 * allocate a kmem_cache_node structure in order to bring the node
4722 mutex_lock(&slab_mutex);
4723 list_for_each_entry(s, &slab_caches, list) {
4725 * The structure may already exist if the node was previously
4726 * onlined and offlined.
4728 if (get_node(s, nid))
4731 * XXX: kmem_cache_alloc_node will fallback to other nodes
4732 * since memory is not yet available from the node that
4735 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4740 init_kmem_cache_node(n);
4744 * Any cache created after this point will also have kmem_cache_node
4745 * initialized for the new node.
4747 node_set(nid, slab_nodes);
4749 mutex_unlock(&slab_mutex);
4753 static int slab_memory_callback(struct notifier_block *self,
4754 unsigned long action, void *arg)
4759 case MEM_GOING_ONLINE:
4760 ret = slab_mem_going_online_callback(arg);
4762 case MEM_GOING_OFFLINE:
4763 ret = slab_mem_going_offline_callback(arg);
4766 case MEM_CANCEL_ONLINE:
4767 slab_mem_offline_callback(arg);
4770 case MEM_CANCEL_OFFLINE:
4774 ret = notifier_from_errno(ret);
4780 static struct notifier_block slab_memory_callback_nb = {
4781 .notifier_call = slab_memory_callback,
4782 .priority = SLAB_CALLBACK_PRI,
4785 /********************************************************************
4786 * Basic setup of slabs
4787 *******************************************************************/
4790 * Used for early kmem_cache structures that were allocated using
4791 * the page allocator. Allocate them properly then fix up the pointers
4792 * that may be pointing to the wrong kmem_cache structure.
4795 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4798 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4799 struct kmem_cache_node *n;
4801 memcpy(s, static_cache, kmem_cache->object_size);
4804 * This runs very early, and only the boot processor is supposed to be
4805 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4808 __flush_cpu_slab(s, smp_processor_id());
4809 for_each_kmem_cache_node(s, node, n) {
4812 list_for_each_entry(p, &n->partial, slab_list)
4815 #ifdef CONFIG_SLUB_DEBUG
4816 list_for_each_entry(p, &n->full, slab_list)
4820 list_add(&s->list, &slab_caches);
4824 void __init kmem_cache_init(void)
4826 static __initdata struct kmem_cache boot_kmem_cache,
4827 boot_kmem_cache_node;
4830 if (debug_guardpage_minorder())
4833 /* Print slub debugging pointers without hashing */
4834 if (__slub_debug_enabled())
4835 no_hash_pointers_enable(NULL);
4837 kmem_cache_node = &boot_kmem_cache_node;
4838 kmem_cache = &boot_kmem_cache;
4841 * Initialize the nodemask for which we will allocate per node
4842 * structures. Here we don't need taking slab_mutex yet.
4844 for_each_node_state(node, N_NORMAL_MEMORY)
4845 node_set(node, slab_nodes);
4847 create_boot_cache(kmem_cache_node, "kmem_cache_node",
4848 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
4850 register_hotmemory_notifier(&slab_memory_callback_nb);
4852 /* Able to allocate the per node structures */
4853 slab_state = PARTIAL;
4855 create_boot_cache(kmem_cache, "kmem_cache",
4856 offsetof(struct kmem_cache, node) +
4857 nr_node_ids * sizeof(struct kmem_cache_node *),
4858 SLAB_HWCACHE_ALIGN, 0, 0);
4860 kmem_cache = bootstrap(&boot_kmem_cache);
4861 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4863 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4864 setup_kmalloc_cache_index_table();
4865 create_kmalloc_caches(0);
4867 /* Setup random freelists for each cache */
4868 init_freelist_randomization();
4870 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4873 pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
4875 slub_min_order, slub_max_order, slub_min_objects,
4876 nr_cpu_ids, nr_node_ids);
4879 void __init kmem_cache_init_late(void)
4884 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
4885 slab_flags_t flags, void (*ctor)(void *))
4887 struct kmem_cache *s;
4889 s = find_mergeable(size, align, flags, name, ctor);
4894 * Adjust the object sizes so that we clear
4895 * the complete object on kzalloc.
4897 s->object_size = max(s->object_size, size);
4898 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
4900 if (sysfs_slab_alias(s, name)) {
4909 int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
4913 err = kmem_cache_open(s, flags);
4917 /* Mutex is not taken during early boot */
4918 if (slab_state <= UP)
4921 err = sysfs_slab_add(s);
4923 __kmem_cache_release(s);
4927 if (s->flags & SLAB_STORE_USER)
4928 debugfs_slab_add(s);
4933 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4935 struct kmem_cache *s;
4938 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4939 return kmalloc_large(size, gfpflags);
4941 s = kmalloc_slab(size, gfpflags);
4943 if (unlikely(ZERO_OR_NULL_PTR(s)))
4946 ret = slab_alloc(s, NULL, gfpflags, caller, size);
4948 /* Honor the call site pointer we received. */
4949 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4953 EXPORT_SYMBOL(__kmalloc_track_caller);
4956 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4957 int node, unsigned long caller)
4959 struct kmem_cache *s;
4962 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4963 ret = kmalloc_large_node(size, gfpflags, node);
4965 trace_kmalloc_node(caller, ret,
4966 size, PAGE_SIZE << get_order(size),
4972 s = kmalloc_slab(size, gfpflags);
4974 if (unlikely(ZERO_OR_NULL_PTR(s)))
4977 ret = slab_alloc_node(s, NULL, gfpflags, node, caller, size);
4979 /* Honor the call site pointer we received. */
4980 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4984 EXPORT_SYMBOL(__kmalloc_node_track_caller);
4988 static int count_inuse(struct slab *slab)
4993 static int count_total(struct slab *slab)
4995 return slab->objects;
4999 #ifdef CONFIG_SLUB_DEBUG
5000 static void validate_slab(struct kmem_cache *s, struct slab *slab,
5001 unsigned long *obj_map)
5004 void *addr = slab_address(slab);
5005 unsigned long flags;
5007 slab_lock(slab, &flags);
5009 if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
5012 /* Now we know that a valid freelist exists */
5013 __fill_map(obj_map, s, slab);
5014 for_each_object(p, s, addr, slab->objects) {
5015 u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
5016 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
5018 if (!check_object(s, slab, p, val))
5022 slab_unlock(slab, &flags);
5025 static int validate_slab_node(struct kmem_cache *s,
5026 struct kmem_cache_node *n, unsigned long *obj_map)
5028 unsigned long count = 0;
5030 unsigned long flags;
5032 spin_lock_irqsave(&n->list_lock, flags);
5034 list_for_each_entry(slab, &n->partial, slab_list) {
5035 validate_slab(s, slab, obj_map);
5038 if (count != n->nr_partial) {
5039 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
5040 s->name, count, n->nr_partial);
5041 slab_add_kunit_errors();
5044 if (!(s->flags & SLAB_STORE_USER))
5047 list_for_each_entry(slab, &n->full, slab_list) {
5048 validate_slab(s, slab, obj_map);
5051 if (count != atomic_long_read(&n->nr_slabs)) {
5052 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
5053 s->name, count, atomic_long_read(&n->nr_slabs));
5054 slab_add_kunit_errors();
5058 spin_unlock_irqrestore(&n->list_lock, flags);
5062 long validate_slab_cache(struct kmem_cache *s)
5065 unsigned long count = 0;
5066 struct kmem_cache_node *n;
5067 unsigned long *obj_map;
5069 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
5074 for_each_kmem_cache_node(s, node, n)
5075 count += validate_slab_node(s, n, obj_map);
5077 bitmap_free(obj_map);
5081 EXPORT_SYMBOL(validate_slab_cache);
5083 #ifdef CONFIG_DEBUG_FS
5085 * Generate lists of code addresses where slabcache objects are allocated
5090 depot_stack_handle_t handle;
5091 unsigned long count;
5098 DECLARE_BITMAP(cpus, NR_CPUS);
5104 unsigned long count;
5105 struct location *loc;
5109 static struct dentry *slab_debugfs_root;
5111 static void free_loc_track(struct loc_track *t)
5114 free_pages((unsigned long)t->loc,
5115 get_order(sizeof(struct location) * t->max));
5118 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
5123 order = get_order(sizeof(struct location) * max);
5125 l = (void *)__get_free_pages(flags, order);
5130 memcpy(l, t->loc, sizeof(struct location) * t->count);
5138 static int add_location(struct loc_track *t, struct kmem_cache *s,
5139 const struct track *track)
5141 long start, end, pos;
5143 unsigned long caddr, chandle;
5144 unsigned long age = jiffies - track->when;
5145 depot_stack_handle_t handle = 0;
5147 #ifdef CONFIG_STACKDEPOT
5148 handle = READ_ONCE(track->handle);
5154 pos = start + (end - start + 1) / 2;
5157 * There is nothing at "end". If we end up there
5158 * we need to add something to before end.
5163 caddr = t->loc[pos].addr;
5164 chandle = t->loc[pos].handle;
5165 if ((track->addr == caddr) && (handle == chandle)) {
5171 if (age < l->min_time)
5173 if (age > l->max_time)
5176 if (track->pid < l->min_pid)
5177 l->min_pid = track->pid;
5178 if (track->pid > l->max_pid)
5179 l->max_pid = track->pid;
5181 cpumask_set_cpu(track->cpu,
5182 to_cpumask(l->cpus));
5184 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5188 if (track->addr < caddr)
5190 else if (track->addr == caddr && handle < chandle)
5197 * Not found. Insert new tracking element.
5199 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
5205 (t->count - pos) * sizeof(struct location));
5208 l->addr = track->addr;
5212 l->min_pid = track->pid;
5213 l->max_pid = track->pid;
5215 cpumask_clear(to_cpumask(l->cpus));
5216 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
5217 nodes_clear(l->nodes);
5218 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5222 static void process_slab(struct loc_track *t, struct kmem_cache *s,
5223 struct slab *slab, enum track_item alloc,
5224 unsigned long *obj_map)
5226 void *addr = slab_address(slab);
5229 __fill_map(obj_map, s, slab);
5231 for_each_object(p, s, addr, slab->objects)
5232 if (!test_bit(__obj_to_index(s, addr, p), obj_map))
5233 add_location(t, s, get_track(s, p, alloc));
5235 #endif /* CONFIG_DEBUG_FS */
5236 #endif /* CONFIG_SLUB_DEBUG */
5239 enum slab_stat_type {
5240 SL_ALL, /* All slabs */
5241 SL_PARTIAL, /* Only partially allocated slabs */
5242 SL_CPU, /* Only slabs used for cpu caches */
5243 SL_OBJECTS, /* Determine allocated objects not slabs */
5244 SL_TOTAL /* Determine object capacity not slabs */
5247 #define SO_ALL (1 << SL_ALL)
5248 #define SO_PARTIAL (1 << SL_PARTIAL)
5249 #define SO_CPU (1 << SL_CPU)
5250 #define SO_OBJECTS (1 << SL_OBJECTS)
5251 #define SO_TOTAL (1 << SL_TOTAL)
5253 static ssize_t show_slab_objects(struct kmem_cache *s,
5254 char *buf, unsigned long flags)
5256 unsigned long total = 0;
5259 unsigned long *nodes;
5262 nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
5266 if (flags & SO_CPU) {
5269 for_each_possible_cpu(cpu) {
5270 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
5275 slab = READ_ONCE(c->slab);
5279 node = slab_nid(slab);
5280 if (flags & SO_TOTAL)
5282 else if (flags & SO_OBJECTS)
5290 #ifdef CONFIG_SLUB_CPU_PARTIAL
5291 slab = slub_percpu_partial_read_once(c);
5293 node = slab_nid(slab);
5294 if (flags & SO_TOTAL)
5296 else if (flags & SO_OBJECTS)
5308 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
5309 * already held which will conflict with an existing lock order:
5311 * mem_hotplug_lock->slab_mutex->kernfs_mutex
5313 * We don't really need mem_hotplug_lock (to hold off
5314 * slab_mem_going_offline_callback) here because slab's memory hot
5315 * unplug code doesn't destroy the kmem_cache->node[] data.
5318 #ifdef CONFIG_SLUB_DEBUG
5319 if (flags & SO_ALL) {
5320 struct kmem_cache_node *n;
5322 for_each_kmem_cache_node(s, node, n) {
5324 if (flags & SO_TOTAL)
5325 x = atomic_long_read(&n->total_objects);
5326 else if (flags & SO_OBJECTS)
5327 x = atomic_long_read(&n->total_objects) -
5328 count_partial(n, count_free);
5330 x = atomic_long_read(&n->nr_slabs);
5337 if (flags & SO_PARTIAL) {
5338 struct kmem_cache_node *n;
5340 for_each_kmem_cache_node(s, node, n) {
5341 if (flags & SO_TOTAL)
5342 x = count_partial(n, count_total);
5343 else if (flags & SO_OBJECTS)
5344 x = count_partial(n, count_inuse);
5352 len += sysfs_emit_at(buf, len, "%lu", total);
5354 for (node = 0; node < nr_node_ids; node++) {
5356 len += sysfs_emit_at(buf, len, " N%d=%lu",
5360 len += sysfs_emit_at(buf, len, "\n");
5366 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
5367 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
5369 struct slab_attribute {
5370 struct attribute attr;
5371 ssize_t (*show)(struct kmem_cache *s, char *buf);
5372 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
5375 #define SLAB_ATTR_RO(_name) \
5376 static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
5378 #define SLAB_ATTR(_name) \
5379 static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
5381 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
5383 return sysfs_emit(buf, "%u\n", s->size);
5385 SLAB_ATTR_RO(slab_size);
5387 static ssize_t align_show(struct kmem_cache *s, char *buf)
5389 return sysfs_emit(buf, "%u\n", s->align);
5391 SLAB_ATTR_RO(align);
5393 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
5395 return sysfs_emit(buf, "%u\n", s->object_size);
5397 SLAB_ATTR_RO(object_size);
5399 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
5401 return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
5403 SLAB_ATTR_RO(objs_per_slab);
5405 static ssize_t order_show(struct kmem_cache *s, char *buf)
5407 return sysfs_emit(buf, "%u\n", oo_order(s->oo));
5409 SLAB_ATTR_RO(order);
5411 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
5413 return sysfs_emit(buf, "%lu\n", s->min_partial);
5416 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
5422 err = kstrtoul(buf, 10, &min);
5426 s->min_partial = min;
5429 SLAB_ATTR(min_partial);
5431 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
5433 unsigned int nr_partial = 0;
5434 #ifdef CONFIG_SLUB_CPU_PARTIAL
5435 nr_partial = s->cpu_partial;
5438 return sysfs_emit(buf, "%u\n", nr_partial);
5441 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
5444 unsigned int objects;
5447 err = kstrtouint(buf, 10, &objects);
5450 if (objects && !kmem_cache_has_cpu_partial(s))
5453 slub_set_cpu_partial(s, objects);
5457 SLAB_ATTR(cpu_partial);
5459 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
5463 return sysfs_emit(buf, "%pS\n", s->ctor);
5467 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
5469 return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
5471 SLAB_ATTR_RO(aliases);
5473 static ssize_t partial_show(struct kmem_cache *s, char *buf)
5475 return show_slab_objects(s, buf, SO_PARTIAL);
5477 SLAB_ATTR_RO(partial);
5479 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5481 return show_slab_objects(s, buf, SO_CPU);
5483 SLAB_ATTR_RO(cpu_slabs);
5485 static ssize_t objects_show(struct kmem_cache *s, char *buf)
5487 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5489 SLAB_ATTR_RO(objects);
5491 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5493 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5495 SLAB_ATTR_RO(objects_partial);
5497 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5501 int cpu __maybe_unused;
5504 #ifdef CONFIG_SLUB_CPU_PARTIAL
5505 for_each_online_cpu(cpu) {
5508 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5511 slabs += slab->slabs;
5515 /* Approximate half-full slabs, see slub_set_cpu_partial() */
5516 objects = (slabs * oo_objects(s->oo)) / 2;
5517 len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
5519 #if defined(CONFIG_SLUB_CPU_PARTIAL) && defined(CONFIG_SMP)
5520 for_each_online_cpu(cpu) {
5523 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5525 slabs = READ_ONCE(slab->slabs);
5526 objects = (slabs * oo_objects(s->oo)) / 2;
5527 len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
5528 cpu, objects, slabs);
5532 len += sysfs_emit_at(buf, len, "\n");
5536 SLAB_ATTR_RO(slabs_cpu_partial);
5538 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5540 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5542 SLAB_ATTR_RO(reclaim_account);
5544 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5546 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5548 SLAB_ATTR_RO(hwcache_align);
5550 #ifdef CONFIG_ZONE_DMA
5551 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5553 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5555 SLAB_ATTR_RO(cache_dma);
5558 static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5560 return sysfs_emit(buf, "%u\n", s->usersize);
5562 SLAB_ATTR_RO(usersize);
5564 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5566 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5568 SLAB_ATTR_RO(destroy_by_rcu);
5570 #ifdef CONFIG_SLUB_DEBUG
5571 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5573 return show_slab_objects(s, buf, SO_ALL);
5575 SLAB_ATTR_RO(slabs);
5577 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5579 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5581 SLAB_ATTR_RO(total_objects);
5583 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5585 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5587 SLAB_ATTR_RO(sanity_checks);
5589 static ssize_t trace_show(struct kmem_cache *s, char *buf)
5591 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5593 SLAB_ATTR_RO(trace);
5595 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5597 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5600 SLAB_ATTR_RO(red_zone);
5602 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5604 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
5607 SLAB_ATTR_RO(poison);
5609 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5611 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5614 SLAB_ATTR_RO(store_user);
5616 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5621 static ssize_t validate_store(struct kmem_cache *s,
5622 const char *buf, size_t length)
5626 if (buf[0] == '1') {
5627 ret = validate_slab_cache(s);
5633 SLAB_ATTR(validate);
5635 #endif /* CONFIG_SLUB_DEBUG */
5637 #ifdef CONFIG_FAILSLAB
5638 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5640 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5642 SLAB_ATTR_RO(failslab);
5645 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5650 static ssize_t shrink_store(struct kmem_cache *s,
5651 const char *buf, size_t length)
5654 kmem_cache_shrink(s);
5662 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5664 return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5667 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5668 const char *buf, size_t length)
5673 err = kstrtouint(buf, 10, &ratio);
5679 s->remote_node_defrag_ratio = ratio * 10;
5683 SLAB_ATTR(remote_node_defrag_ratio);
5686 #ifdef CONFIG_SLUB_STATS
5687 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5689 unsigned long sum = 0;
5692 int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
5697 for_each_online_cpu(cpu) {
5698 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5704 len += sysfs_emit_at(buf, len, "%lu", sum);
5707 for_each_online_cpu(cpu) {
5709 len += sysfs_emit_at(buf, len, " C%d=%u",
5714 len += sysfs_emit_at(buf, len, "\n");
5719 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5723 for_each_online_cpu(cpu)
5724 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5727 #define STAT_ATTR(si, text) \
5728 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5730 return show_stat(s, buf, si); \
5732 static ssize_t text##_store(struct kmem_cache *s, \
5733 const char *buf, size_t length) \
5735 if (buf[0] != '0') \
5737 clear_stat(s, si); \
5742 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5743 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5744 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5745 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5746 STAT_ATTR(FREE_FROZEN, free_frozen);
5747 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5748 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5749 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5750 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5751 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5752 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5753 STAT_ATTR(FREE_SLAB, free_slab);
5754 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5755 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5756 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5757 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5758 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5759 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5760 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5761 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5762 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5763 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5764 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5765 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5766 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5767 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5768 #endif /* CONFIG_SLUB_STATS */
5770 static struct attribute *slab_attrs[] = {
5771 &slab_size_attr.attr,
5772 &object_size_attr.attr,
5773 &objs_per_slab_attr.attr,
5775 &min_partial_attr.attr,
5776 &cpu_partial_attr.attr,
5778 &objects_partial_attr.attr,
5780 &cpu_slabs_attr.attr,
5784 &hwcache_align_attr.attr,
5785 &reclaim_account_attr.attr,
5786 &destroy_by_rcu_attr.attr,
5788 &slabs_cpu_partial_attr.attr,
5789 #ifdef CONFIG_SLUB_DEBUG
5790 &total_objects_attr.attr,
5792 &sanity_checks_attr.attr,
5794 &red_zone_attr.attr,
5796 &store_user_attr.attr,
5797 &validate_attr.attr,
5799 #ifdef CONFIG_ZONE_DMA
5800 &cache_dma_attr.attr,
5803 &remote_node_defrag_ratio_attr.attr,
5805 #ifdef CONFIG_SLUB_STATS
5806 &alloc_fastpath_attr.attr,
5807 &alloc_slowpath_attr.attr,
5808 &free_fastpath_attr.attr,
5809 &free_slowpath_attr.attr,
5810 &free_frozen_attr.attr,
5811 &free_add_partial_attr.attr,
5812 &free_remove_partial_attr.attr,
5813 &alloc_from_partial_attr.attr,
5814 &alloc_slab_attr.attr,
5815 &alloc_refill_attr.attr,
5816 &alloc_node_mismatch_attr.attr,
5817 &free_slab_attr.attr,
5818 &cpuslab_flush_attr.attr,
5819 &deactivate_full_attr.attr,
5820 &deactivate_empty_attr.attr,
5821 &deactivate_to_head_attr.attr,
5822 &deactivate_to_tail_attr.attr,
5823 &deactivate_remote_frees_attr.attr,
5824 &deactivate_bypass_attr.attr,
5825 &order_fallback_attr.attr,
5826 &cmpxchg_double_fail_attr.attr,
5827 &cmpxchg_double_cpu_fail_attr.attr,
5828 &cpu_partial_alloc_attr.attr,
5829 &cpu_partial_free_attr.attr,
5830 &cpu_partial_node_attr.attr,
5831 &cpu_partial_drain_attr.attr,
5833 #ifdef CONFIG_FAILSLAB
5834 &failslab_attr.attr,
5836 &usersize_attr.attr,
5841 static const struct attribute_group slab_attr_group = {
5842 .attrs = slab_attrs,
5845 static ssize_t slab_attr_show(struct kobject *kobj,
5846 struct attribute *attr,
5849 struct slab_attribute *attribute;
5850 struct kmem_cache *s;
5853 attribute = to_slab_attr(attr);
5856 if (!attribute->show)
5859 err = attribute->show(s, buf);
5864 static ssize_t slab_attr_store(struct kobject *kobj,
5865 struct attribute *attr,
5866 const char *buf, size_t len)
5868 struct slab_attribute *attribute;
5869 struct kmem_cache *s;
5872 attribute = to_slab_attr(attr);
5875 if (!attribute->store)
5878 err = attribute->store(s, buf, len);
5882 static void kmem_cache_release(struct kobject *k)
5884 slab_kmem_cache_release(to_slab(k));
5887 static const struct sysfs_ops slab_sysfs_ops = {
5888 .show = slab_attr_show,
5889 .store = slab_attr_store,
5892 static struct kobj_type slab_ktype = {
5893 .sysfs_ops = &slab_sysfs_ops,
5894 .release = kmem_cache_release,
5897 static struct kset *slab_kset;
5899 static inline struct kset *cache_kset(struct kmem_cache *s)
5904 #define ID_STR_LENGTH 64
5906 /* Create a unique string id for a slab cache:
5908 * Format :[flags-]size
5910 static char *create_unique_id(struct kmem_cache *s)
5912 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5919 * First flags affecting slabcache operations. We will only
5920 * get here for aliasable slabs so we do not need to support
5921 * too many flags. The flags here must cover all flags that
5922 * are matched during merging to guarantee that the id is
5925 if (s->flags & SLAB_CACHE_DMA)
5927 if (s->flags & SLAB_CACHE_DMA32)
5929 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5931 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5933 if (s->flags & SLAB_ACCOUNT)
5937 p += sprintf(p, "%07u", s->size);
5939 BUG_ON(p > name + ID_STR_LENGTH - 1);
5943 static int sysfs_slab_add(struct kmem_cache *s)
5947 struct kset *kset = cache_kset(s);
5948 int unmergeable = slab_unmergeable(s);
5951 kobject_init(&s->kobj, &slab_ktype);
5955 if (!unmergeable && disable_higher_order_debug &&
5956 (slub_debug & DEBUG_METADATA_FLAGS))
5961 * Slabcache can never be merged so we can use the name proper.
5962 * This is typically the case for debug situations. In that
5963 * case we can catch duplicate names easily.
5965 sysfs_remove_link(&slab_kset->kobj, s->name);
5969 * Create a unique name for the slab as a target
5972 name = create_unique_id(s);
5975 s->kobj.kset = kset;
5976 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5980 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5985 /* Setup first alias */
5986 sysfs_slab_alias(s, s->name);
5993 kobject_del(&s->kobj);
5997 void sysfs_slab_unlink(struct kmem_cache *s)
5999 if (slab_state >= FULL)
6000 kobject_del(&s->kobj);
6003 void sysfs_slab_release(struct kmem_cache *s)
6005 if (slab_state >= FULL)
6006 kobject_put(&s->kobj);
6010 * Need to buffer aliases during bootup until sysfs becomes
6011 * available lest we lose that information.
6013 struct saved_alias {
6014 struct kmem_cache *s;
6016 struct saved_alias *next;
6019 static struct saved_alias *alias_list;
6021 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
6023 struct saved_alias *al;
6025 if (slab_state == FULL) {
6027 * If we have a leftover link then remove it.
6029 sysfs_remove_link(&slab_kset->kobj, name);
6030 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
6033 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
6039 al->next = alias_list;
6044 static int __init slab_sysfs_init(void)
6046 struct kmem_cache *s;
6049 mutex_lock(&slab_mutex);
6051 slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
6053 mutex_unlock(&slab_mutex);
6054 pr_err("Cannot register slab subsystem.\n");
6060 list_for_each_entry(s, &slab_caches, list) {
6061 err = sysfs_slab_add(s);
6063 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
6067 while (alias_list) {
6068 struct saved_alias *al = alias_list;
6070 alias_list = alias_list->next;
6071 err = sysfs_slab_alias(al->s, al->name);
6073 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
6078 mutex_unlock(&slab_mutex);
6082 __initcall(slab_sysfs_init);
6083 #endif /* CONFIG_SYSFS */
6085 #if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
6086 static int slab_debugfs_show(struct seq_file *seq, void *v)
6088 struct loc_track *t = seq->private;
6092 idx = (unsigned long) t->idx;
6093 if (idx < t->count) {
6096 seq_printf(seq, "%7ld ", l->count);
6099 seq_printf(seq, "%pS", (void *)l->addr);
6101 seq_puts(seq, "<not-available>");
6103 if (l->sum_time != l->min_time) {
6104 seq_printf(seq, " age=%ld/%llu/%ld",
6105 l->min_time, div_u64(l->sum_time, l->count),
6108 seq_printf(seq, " age=%ld", l->min_time);
6110 if (l->min_pid != l->max_pid)
6111 seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
6113 seq_printf(seq, " pid=%ld",
6116 if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
6117 seq_printf(seq, " cpus=%*pbl",
6118 cpumask_pr_args(to_cpumask(l->cpus)));
6120 if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
6121 seq_printf(seq, " nodes=%*pbl",
6122 nodemask_pr_args(&l->nodes));
6124 #ifdef CONFIG_STACKDEPOT
6126 depot_stack_handle_t handle;
6127 unsigned long *entries;
6128 unsigned int nr_entries, j;
6130 handle = READ_ONCE(l->handle);
6132 nr_entries = stack_depot_fetch(handle, &entries);
6133 seq_puts(seq, "\n");
6134 for (j = 0; j < nr_entries; j++)
6135 seq_printf(seq, " %pS\n", (void *)entries[j]);
6139 seq_puts(seq, "\n");
6142 if (!idx && !t->count)
6143 seq_puts(seq, "No data\n");
6148 static void slab_debugfs_stop(struct seq_file *seq, void *v)
6152 static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
6154 struct loc_track *t = seq->private;
6157 if (*ppos <= t->count)
6163 static int cmp_loc_by_count(const void *a, const void *b, const void *data)
6165 struct location *loc1 = (struct location *)a;
6166 struct location *loc2 = (struct location *)b;
6168 if (loc1->count > loc2->count)
6174 static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
6176 struct loc_track *t = seq->private;
6182 static const struct seq_operations slab_debugfs_sops = {
6183 .start = slab_debugfs_start,
6184 .next = slab_debugfs_next,
6185 .stop = slab_debugfs_stop,
6186 .show = slab_debugfs_show,
6189 static int slab_debug_trace_open(struct inode *inode, struct file *filep)
6192 struct kmem_cache_node *n;
6193 enum track_item alloc;
6195 struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
6196 sizeof(struct loc_track));
6197 struct kmem_cache *s = file_inode(filep)->i_private;
6198 unsigned long *obj_map;
6203 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
6205 seq_release_private(inode, filep);
6209 if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
6210 alloc = TRACK_ALLOC;
6214 if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
6215 bitmap_free(obj_map);
6216 seq_release_private(inode, filep);
6220 for_each_kmem_cache_node(s, node, n) {
6221 unsigned long flags;
6224 if (!atomic_long_read(&n->nr_slabs))
6227 spin_lock_irqsave(&n->list_lock, flags);
6228 list_for_each_entry(slab, &n->partial, slab_list)
6229 process_slab(t, s, slab, alloc, obj_map);
6230 list_for_each_entry(slab, &n->full, slab_list)
6231 process_slab(t, s, slab, alloc, obj_map);
6232 spin_unlock_irqrestore(&n->list_lock, flags);
6235 /* Sort locations by count */
6236 sort_r(t->loc, t->count, sizeof(struct location),
6237 cmp_loc_by_count, NULL, NULL);
6239 bitmap_free(obj_map);
6243 static int slab_debug_trace_release(struct inode *inode, struct file *file)
6245 struct seq_file *seq = file->private_data;
6246 struct loc_track *t = seq->private;
6249 return seq_release_private(inode, file);
6252 static const struct file_operations slab_debugfs_fops = {
6253 .open = slab_debug_trace_open,
6255 .llseek = seq_lseek,
6256 .release = slab_debug_trace_release,
6259 static void debugfs_slab_add(struct kmem_cache *s)
6261 struct dentry *slab_cache_dir;
6263 if (unlikely(!slab_debugfs_root))
6266 slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
6268 debugfs_create_file("alloc_traces", 0400,
6269 slab_cache_dir, s, &slab_debugfs_fops);
6271 debugfs_create_file("free_traces", 0400,
6272 slab_cache_dir, s, &slab_debugfs_fops);
6275 void debugfs_slab_release(struct kmem_cache *s)
6277 debugfs_remove_recursive(debugfs_lookup(s->name, slab_debugfs_root));
6280 static int __init slab_debugfs_init(void)
6282 struct kmem_cache *s;
6284 slab_debugfs_root = debugfs_create_dir("slab", NULL);
6286 list_for_each_entry(s, &slab_caches, list)
6287 if (s->flags & SLAB_STORE_USER)
6288 debugfs_slab_add(s);
6293 __initcall(slab_debugfs_init);
6296 * The /proc/slabinfo ABI
6298 #ifdef CONFIG_SLUB_DEBUG
6299 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
6301 unsigned long nr_slabs = 0;
6302 unsigned long nr_objs = 0;
6303 unsigned long nr_free = 0;
6305 struct kmem_cache_node *n;
6307 for_each_kmem_cache_node(s, node, n) {
6308 nr_slabs += node_nr_slabs(n);
6309 nr_objs += node_nr_objs(n);
6310 nr_free += count_partial(n, count_free);
6313 sinfo->active_objs = nr_objs - nr_free;
6314 sinfo->num_objs = nr_objs;
6315 sinfo->active_slabs = nr_slabs;
6316 sinfo->num_slabs = nr_slabs;
6317 sinfo->objects_per_slab = oo_objects(s->oo);
6318 sinfo->cache_order = oo_order(s->oo);
6321 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
6325 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
6326 size_t count, loff_t *ppos)
6330 #endif /* CONFIG_SLUB_DEBUG */