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/debugobjects.h>
30 #include <linux/kallsyms.h>
31 #include <linux/kfence.h>
32 #include <linux/memory.h>
33 #include <linux/math64.h>
34 #include <linux/fault-inject.h>
35 #include <linux/stacktrace.h>
36 #include <linux/prefetch.h>
37 #include <linux/memcontrol.h>
38 #include <linux/random.h>
39 #include <kunit/test.h>
41 #include <linux/debugfs.h>
42 #include <trace/events/kmem.h>
48 * 1. slab_mutex (Global Mutex)
49 * 2. node->list_lock (Spinlock)
50 * 3. kmem_cache->cpu_slab->lock (Local lock)
51 * 4. slab_lock(page) (Only on some arches or for debugging)
52 * 5. object_map_lock (Only for debugging)
56 * The role of the slab_mutex is to protect the list of all the slabs
57 * and to synchronize major metadata changes to slab cache structures.
58 * Also synchronizes memory hotplug callbacks.
62 * The slab_lock is a wrapper around the page lock, thus it is a bit
65 * The slab_lock is only used for debugging and on arches that do not
66 * have the ability to do a cmpxchg_double. It only protects:
67 * A. page->freelist -> List of object free in a page
68 * B. page->inuse -> Number of objects in use
69 * C. page->objects -> Number of objects in page
70 * D. page->frozen -> frozen state
74 * If a slab is frozen then it is exempt from list management. It is not
75 * on any list except per cpu partial list. The processor that froze the
76 * slab is the one who can perform list operations on the page. Other
77 * processors may put objects onto the freelist but the processor that
78 * froze the slab is the only one that can retrieve the objects from the
83 * The list_lock protects the partial and full list on each node and
84 * the partial slab counter. If taken then no new slabs may be added or
85 * removed from the lists nor make the number of partial slabs be modified.
86 * (Note that the total number of slabs is an atomic value that may be
87 * modified without taking the list lock).
89 * The list_lock is a centralized lock and thus we avoid taking it as
90 * much as possible. As long as SLUB does not have to handle partial
91 * slabs, operations can continue without any centralized lock. F.e.
92 * allocating a long series of objects that fill up slabs does not require
95 * cpu_slab->lock local lock
97 * This locks protect slowpath manipulation of all kmem_cache_cpu fields
98 * except the stat counters. This is a percpu structure manipulated only by
99 * the local cpu, so the lock protects against being preempted or interrupted
100 * by an irq. Fast path operations rely on lockless operations instead.
101 * On PREEMPT_RT, the local lock does not actually disable irqs (and thus
102 * prevent the lockless operations), so fastpath operations also need to take
103 * the lock and are no longer lockless.
107 * The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
108 * are fully lockless when satisfied from the percpu slab (and when
109 * cmpxchg_double is possible to use, otherwise slab_lock is taken).
110 * They also don't disable preemption or migration or irqs. They rely on
111 * the transaction id (tid) field to detect being preempted or moved to
114 * irq, preemption, migration considerations
116 * Interrupts are disabled as part of list_lock or local_lock operations, or
117 * around the slab_lock operation, in order to make the slab allocator safe
118 * to use in the context of an irq.
120 * In addition, preemption (or migration on PREEMPT_RT) is disabled in the
121 * allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
122 * local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
123 * doesn't have to be revalidated in each section protected by the local lock.
125 * SLUB assigns one slab for allocation to each processor.
126 * Allocations only occur from these slabs called cpu slabs.
128 * Slabs with free elements are kept on a partial list and during regular
129 * operations no list for full slabs is used. If an object in a full slab is
130 * freed then the slab will show up again on the partial lists.
131 * We track full slabs for debugging purposes though because otherwise we
132 * cannot scan all objects.
134 * Slabs are freed when they become empty. Teardown and setup is
135 * minimal so we rely on the page allocators per cpu caches for
136 * fast frees and allocs.
138 * page->frozen The slab is frozen and exempt from list processing.
139 * This means that the slab is dedicated to a purpose
140 * such as satisfying allocations for a specific
141 * processor. Objects may be freed in the slab while
142 * it is frozen but slab_free will then skip the usual
143 * list operations. It is up to the processor holding
144 * the slab to integrate the slab into the slab lists
145 * when the slab is no longer needed.
147 * One use of this flag is to mark slabs that are
148 * used for allocations. Then such a slab becomes a cpu
149 * slab. The cpu slab may be equipped with an additional
150 * freelist that allows lockless access to
151 * free objects in addition to the regular freelist
152 * that requires the slab lock.
154 * SLAB_DEBUG_FLAGS Slab requires special handling due to debug
155 * options set. This moves slab handling out of
156 * the fast path and disables lockless freelists.
160 * We could simply use migrate_disable()/enable() but as long as it's a
161 * function call even on !PREEMPT_RT, use inline preempt_disable() there.
163 #ifndef CONFIG_PREEMPT_RT
164 #define slub_get_cpu_ptr(var) get_cpu_ptr(var)
165 #define slub_put_cpu_ptr(var) put_cpu_ptr(var)
167 #define slub_get_cpu_ptr(var) \
172 #define slub_put_cpu_ptr(var) \
179 #ifdef CONFIG_SLUB_DEBUG
180 #ifdef CONFIG_SLUB_DEBUG_ON
181 DEFINE_STATIC_KEY_TRUE(slub_debug_enabled
);
183 DEFINE_STATIC_KEY_FALSE(slub_debug_enabled
);
185 #endif /* CONFIG_SLUB_DEBUG */
187 static inline bool kmem_cache_debug(struct kmem_cache
*s
)
189 return kmem_cache_debug_flags(s
, SLAB_DEBUG_FLAGS
);
192 void *fixup_red_left(struct kmem_cache
*s
, void *p
)
194 if (kmem_cache_debug_flags(s
, SLAB_RED_ZONE
))
195 p
+= s
->red_left_pad
;
200 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache
*s
)
202 #ifdef CONFIG_SLUB_CPU_PARTIAL
203 return !kmem_cache_debug(s
);
210 * Issues still to be resolved:
212 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
214 * - Variable sizing of the per node arrays
217 /* Enable to log cmpxchg failures */
218 #undef SLUB_DEBUG_CMPXCHG
221 * Minimum number of partial slabs. These will be left on the partial
222 * lists even if they are empty. kmem_cache_shrink may reclaim them.
224 #define MIN_PARTIAL 5
227 * Maximum number of desirable partial slabs.
228 * The existence of more partial slabs makes kmem_cache_shrink
229 * sort the partial list by the number of objects in use.
231 #define MAX_PARTIAL 10
233 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
234 SLAB_POISON | SLAB_STORE_USER)
237 * These debug flags cannot use CMPXCHG because there might be consistency
238 * issues when checking or reading debug information
240 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
245 * Debugging flags that require metadata to be stored in the slab. These get
246 * disabled when slub_debug=O is used and a cache's min order increases with
249 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
252 #define OO_MASK ((1 << OO_SHIFT) - 1)
253 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
255 /* Internal SLUB flags */
257 #define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
258 /* Use cmpxchg_double */
259 #define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
262 * Tracking user of a slab.
264 #define TRACK_ADDRS_COUNT 16
266 unsigned long addr
; /* Called from address */
267 #ifdef CONFIG_STACKTRACE
268 unsigned long addrs
[TRACK_ADDRS_COUNT
]; /* Called from address */
270 int cpu
; /* Was running on cpu */
271 int pid
; /* Pid context */
272 unsigned long when
; /* When did the operation occur */
275 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
278 static int sysfs_slab_add(struct kmem_cache
*);
279 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
281 static inline int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
282 static inline int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
)
286 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
287 static void debugfs_slab_add(struct kmem_cache
*);
289 static inline void debugfs_slab_add(struct kmem_cache
*s
) { }
292 static inline void stat(const struct kmem_cache
*s
, enum stat_item si
)
294 #ifdef CONFIG_SLUB_STATS
296 * The rmw is racy on a preemptible kernel but this is acceptable, so
297 * avoid this_cpu_add()'s irq-disable overhead.
299 raw_cpu_inc(s
->cpu_slab
->stat
[si
]);
304 * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
305 * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
306 * differ during memory hotplug/hotremove operations.
307 * Protected by slab_mutex.
309 static nodemask_t slab_nodes
;
311 /********************************************************************
312 * Core slab cache functions
313 *******************************************************************/
316 * Returns freelist pointer (ptr). With hardening, this is obfuscated
317 * with an XOR of the address where the pointer is held and a per-cache
320 static inline void *freelist_ptr(const struct kmem_cache
*s
, void *ptr
,
321 unsigned long ptr_addr
)
323 #ifdef CONFIG_SLAB_FREELIST_HARDENED
325 * When CONFIG_KASAN_SW/HW_TAGS is enabled, ptr_addr might be tagged.
326 * Normally, this doesn't cause any issues, as both set_freepointer()
327 * and get_freepointer() are called with a pointer with the same tag.
328 * However, there are some issues with CONFIG_SLUB_DEBUG code. For
329 * example, when __free_slub() iterates over objects in a cache, it
330 * passes untagged pointers to check_object(). check_object() in turns
331 * calls get_freepointer() with an untagged pointer, which causes the
332 * freepointer to be restored incorrectly.
334 return (void *)((unsigned long)ptr
^ s
->random
^
335 swab((unsigned long)kasan_reset_tag((void *)ptr_addr
)));
341 /* Returns the freelist pointer recorded at location ptr_addr. */
342 static inline void *freelist_dereference(const struct kmem_cache
*s
,
345 return freelist_ptr(s
, (void *)*(unsigned long *)(ptr_addr
),
346 (unsigned long)ptr_addr
);
349 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
351 object
= kasan_reset_tag(object
);
352 return freelist_dereference(s
, object
+ s
->offset
);
355 static void prefetch_freepointer(const struct kmem_cache
*s
, void *object
)
357 prefetch(object
+ s
->offset
);
360 static inline void *get_freepointer_safe(struct kmem_cache
*s
, void *object
)
362 unsigned long freepointer_addr
;
365 if (!debug_pagealloc_enabled_static())
366 return get_freepointer(s
, object
);
368 object
= kasan_reset_tag(object
);
369 freepointer_addr
= (unsigned long)object
+ s
->offset
;
370 copy_from_kernel_nofault(&p
, (void **)freepointer_addr
, sizeof(p
));
371 return freelist_ptr(s
, p
, freepointer_addr
);
374 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
376 unsigned long freeptr_addr
= (unsigned long)object
+ s
->offset
;
378 #ifdef CONFIG_SLAB_FREELIST_HARDENED
379 BUG_ON(object
== fp
); /* naive detection of double free or corruption */
382 freeptr_addr
= (unsigned long)kasan_reset_tag((void *)freeptr_addr
);
383 *(void **)freeptr_addr
= freelist_ptr(s
, fp
, freeptr_addr
);
386 /* Loop over all objects in a slab */
387 #define for_each_object(__p, __s, __addr, __objects) \
388 for (__p = fixup_red_left(__s, __addr); \
389 __p < (__addr) + (__objects) * (__s)->size; \
392 static inline unsigned int order_objects(unsigned int order
, unsigned int size
)
394 return ((unsigned int)PAGE_SIZE
<< order
) / size
;
397 static inline struct kmem_cache_order_objects
oo_make(unsigned int order
,
400 struct kmem_cache_order_objects x
= {
401 (order
<< OO_SHIFT
) + order_objects(order
, size
)
407 static inline unsigned int oo_order(struct kmem_cache_order_objects x
)
409 return x
.x
>> OO_SHIFT
;
412 static inline unsigned int oo_objects(struct kmem_cache_order_objects x
)
414 return x
.x
& OO_MASK
;
418 * Per slab locking using the pagelock
420 static __always_inline
void __slab_lock(struct page
*page
)
422 VM_BUG_ON_PAGE(PageTail(page
), page
);
423 bit_spin_lock(PG_locked
, &page
->flags
);
426 static __always_inline
void __slab_unlock(struct page
*page
)
428 VM_BUG_ON_PAGE(PageTail(page
), page
);
429 __bit_spin_unlock(PG_locked
, &page
->flags
);
432 static __always_inline
void slab_lock(struct page
*page
, unsigned long *flags
)
434 if (IS_ENABLED(CONFIG_PREEMPT_RT
))
435 local_irq_save(*flags
);
439 static __always_inline
void slab_unlock(struct page
*page
, unsigned long *flags
)
442 if (IS_ENABLED(CONFIG_PREEMPT_RT
))
443 local_irq_restore(*flags
);
447 * Interrupts must be disabled (for the fallback code to work right), typically
448 * by an _irqsave() lock variant. Except on PREEMPT_RT where locks are different
449 * so we disable interrupts as part of slab_[un]lock().
451 static inline bool __cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
452 void *freelist_old
, unsigned long counters_old
,
453 void *freelist_new
, unsigned long counters_new
,
456 if (!IS_ENABLED(CONFIG_PREEMPT_RT
))
457 lockdep_assert_irqs_disabled();
458 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
459 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
460 if (s
->flags
& __CMPXCHG_DOUBLE
) {
461 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
462 freelist_old
, counters_old
,
463 freelist_new
, counters_new
))
468 /* init to 0 to prevent spurious warnings */
469 unsigned long flags
= 0;
471 slab_lock(page
, &flags
);
472 if (page
->freelist
== freelist_old
&&
473 page
->counters
== counters_old
) {
474 page
->freelist
= freelist_new
;
475 page
->counters
= counters_new
;
476 slab_unlock(page
, &flags
);
479 slab_unlock(page
, &flags
);
483 stat(s
, CMPXCHG_DOUBLE_FAIL
);
485 #ifdef SLUB_DEBUG_CMPXCHG
486 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
492 static inline bool cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
493 void *freelist_old
, unsigned long counters_old
,
494 void *freelist_new
, unsigned long counters_new
,
497 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
498 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
499 if (s
->flags
& __CMPXCHG_DOUBLE
) {
500 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
501 freelist_old
, counters_old
,
502 freelist_new
, counters_new
))
509 local_irq_save(flags
);
511 if (page
->freelist
== freelist_old
&&
512 page
->counters
== counters_old
) {
513 page
->freelist
= freelist_new
;
514 page
->counters
= counters_new
;
516 local_irq_restore(flags
);
520 local_irq_restore(flags
);
524 stat(s
, CMPXCHG_DOUBLE_FAIL
);
526 #ifdef SLUB_DEBUG_CMPXCHG
527 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
533 #ifdef CONFIG_SLUB_DEBUG
534 static unsigned long object_map
[BITS_TO_LONGS(MAX_OBJS_PER_PAGE
)];
535 static DEFINE_RAW_SPINLOCK(object_map_lock
);
537 static void __fill_map(unsigned long *obj_map
, struct kmem_cache
*s
,
540 void *addr
= page_address(page
);
543 bitmap_zero(obj_map
, page
->objects
);
545 for (p
= page
->freelist
; p
; p
= get_freepointer(s
, p
))
546 set_bit(__obj_to_index(s
, addr
, p
), obj_map
);
549 #if IS_ENABLED(CONFIG_KUNIT)
550 static bool slab_add_kunit_errors(void)
552 struct kunit_resource
*resource
;
554 if (likely(!current
->kunit_test
))
557 resource
= kunit_find_named_resource(current
->kunit_test
, "slab_errors");
561 (*(int *)resource
->data
)++;
562 kunit_put_resource(resource
);
566 static inline bool slab_add_kunit_errors(void) { return false; }
570 * Determine a map of object in use on a page.
572 * Node listlock must be held to guarantee that the page does
573 * not vanish from under us.
575 static unsigned long *get_map(struct kmem_cache
*s
, struct page
*page
)
576 __acquires(&object_map_lock
)
578 VM_BUG_ON(!irqs_disabled());
580 raw_spin_lock(&object_map_lock
);
582 __fill_map(object_map
, s
, page
);
587 static void put_map(unsigned long *map
) __releases(&object_map_lock
)
589 VM_BUG_ON(map
!= object_map
);
590 raw_spin_unlock(&object_map_lock
);
593 static inline unsigned int size_from_object(struct kmem_cache
*s
)
595 if (s
->flags
& SLAB_RED_ZONE
)
596 return s
->size
- s
->red_left_pad
;
601 static inline void *restore_red_left(struct kmem_cache
*s
, void *p
)
603 if (s
->flags
& SLAB_RED_ZONE
)
604 p
-= s
->red_left_pad
;
612 #if defined(CONFIG_SLUB_DEBUG_ON)
613 static slab_flags_t slub_debug
= DEBUG_DEFAULT_FLAGS
;
615 static slab_flags_t slub_debug
;
618 static char *slub_debug_string
;
619 static int disable_higher_order_debug
;
622 * slub is about to manipulate internal object metadata. This memory lies
623 * outside the range of the allocated object, so accessing it would normally
624 * be reported by kasan as a bounds error. metadata_access_enable() is used
625 * to tell kasan that these accesses are OK.
627 static inline void metadata_access_enable(void)
629 kasan_disable_current();
632 static inline void metadata_access_disable(void)
634 kasan_enable_current();
641 /* Verify that a pointer has an address that is valid within a slab page */
642 static inline int check_valid_pointer(struct kmem_cache
*s
,
643 struct page
*page
, void *object
)
650 base
= page_address(page
);
651 object
= kasan_reset_tag(object
);
652 object
= restore_red_left(s
, object
);
653 if (object
< base
|| object
>= base
+ page
->objects
* s
->size
||
654 (object
- base
) % s
->size
) {
661 static void print_section(char *level
, char *text
, u8
*addr
,
664 metadata_access_enable();
665 print_hex_dump(level
, text
, DUMP_PREFIX_ADDRESS
,
666 16, 1, kasan_reset_tag((void *)addr
), length
, 1);
667 metadata_access_disable();
671 * See comment in calculate_sizes().
673 static inline bool freeptr_outside_object(struct kmem_cache
*s
)
675 return s
->offset
>= s
->inuse
;
679 * Return offset of the end of info block which is inuse + free pointer if
680 * not overlapping with object.
682 static inline unsigned int get_info_end(struct kmem_cache
*s
)
684 if (freeptr_outside_object(s
))
685 return s
->inuse
+ sizeof(void *);
690 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
691 enum track_item alloc
)
695 p
= object
+ get_info_end(s
);
697 return kasan_reset_tag(p
+ alloc
);
700 static void set_track(struct kmem_cache
*s
, void *object
,
701 enum track_item alloc
, unsigned long addr
)
703 struct track
*p
= get_track(s
, object
, alloc
);
706 #ifdef CONFIG_STACKTRACE
707 unsigned int nr_entries
;
709 metadata_access_enable();
710 nr_entries
= stack_trace_save(kasan_reset_tag(p
->addrs
),
711 TRACK_ADDRS_COUNT
, 3);
712 metadata_access_disable();
714 if (nr_entries
< TRACK_ADDRS_COUNT
)
715 p
->addrs
[nr_entries
] = 0;
718 p
->cpu
= smp_processor_id();
719 p
->pid
= current
->pid
;
722 memset(p
, 0, sizeof(struct track
));
726 static void init_tracking(struct kmem_cache
*s
, void *object
)
728 if (!(s
->flags
& SLAB_STORE_USER
))
731 set_track(s
, object
, TRACK_FREE
, 0UL);
732 set_track(s
, object
, TRACK_ALLOC
, 0UL);
735 static void print_track(const char *s
, struct track
*t
, unsigned long pr_time
)
740 pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
741 s
, (void *)t
->addr
, pr_time
- t
->when
, t
->cpu
, t
->pid
);
742 #ifdef CONFIG_STACKTRACE
745 for (i
= 0; i
< TRACK_ADDRS_COUNT
; i
++)
747 pr_err("\t%pS\n", (void *)t
->addrs
[i
]);
754 void print_tracking(struct kmem_cache
*s
, void *object
)
756 unsigned long pr_time
= jiffies
;
757 if (!(s
->flags
& SLAB_STORE_USER
))
760 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
), pr_time
);
761 print_track("Freed", get_track(s
, object
, TRACK_FREE
), pr_time
);
764 static void print_page_info(struct page
*page
)
766 pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%#lx(%pGp)\n",
767 page
, page
->objects
, page
->inuse
, page
->freelist
,
768 page
->flags
, &page
->flags
);
772 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
774 struct va_format vaf
;
780 pr_err("=============================================================================\n");
781 pr_err("BUG %s (%s): %pV\n", s
->name
, print_tainted(), &vaf
);
782 pr_err("-----------------------------------------------------------------------------\n\n");
787 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
789 struct va_format vaf
;
792 if (slab_add_kunit_errors())
798 pr_err("FIX %s: %pV\n", s
->name
, &vaf
);
802 static bool freelist_corrupted(struct kmem_cache
*s
, struct page
*page
,
803 void **freelist
, void *nextfree
)
805 if ((s
->flags
& SLAB_CONSISTENCY_CHECKS
) &&
806 !check_valid_pointer(s
, page
, nextfree
) && freelist
) {
807 object_err(s
, page
, *freelist
, "Freechain corrupt");
809 slab_fix(s
, "Isolate corrupted freechain");
816 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
818 unsigned int off
; /* Offset of last byte */
819 u8
*addr
= page_address(page
);
821 print_tracking(s
, p
);
823 print_page_info(page
);
825 pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
826 p
, p
- addr
, get_freepointer(s
, p
));
828 if (s
->flags
& SLAB_RED_ZONE
)
829 print_section(KERN_ERR
, "Redzone ", p
- s
->red_left_pad
,
831 else if (p
> addr
+ 16)
832 print_section(KERN_ERR
, "Bytes b4 ", p
- 16, 16);
834 print_section(KERN_ERR
, "Object ", p
,
835 min_t(unsigned int, s
->object_size
, PAGE_SIZE
));
836 if (s
->flags
& SLAB_RED_ZONE
)
837 print_section(KERN_ERR
, "Redzone ", p
+ s
->object_size
,
838 s
->inuse
- s
->object_size
);
840 off
= get_info_end(s
);
842 if (s
->flags
& SLAB_STORE_USER
)
843 off
+= 2 * sizeof(struct track
);
845 off
+= kasan_metadata_size(s
);
847 if (off
!= size_from_object(s
))
848 /* Beginning of the filler is the free pointer */
849 print_section(KERN_ERR
, "Padding ", p
+ off
,
850 size_from_object(s
) - off
);
855 void object_err(struct kmem_cache
*s
, struct page
*page
,
856 u8
*object
, char *reason
)
858 if (slab_add_kunit_errors())
861 slab_bug(s
, "%s", reason
);
862 print_trailer(s
, page
, object
);
863 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
866 static __printf(3, 4) void slab_err(struct kmem_cache
*s
, struct page
*page
,
867 const char *fmt
, ...)
872 if (slab_add_kunit_errors())
876 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
878 slab_bug(s
, "%s", buf
);
879 print_page_info(page
);
881 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
884 static void init_object(struct kmem_cache
*s
, void *object
, u8 val
)
886 u8
*p
= kasan_reset_tag(object
);
888 if (s
->flags
& SLAB_RED_ZONE
)
889 memset(p
- s
->red_left_pad
, val
, s
->red_left_pad
);
891 if (s
->flags
& __OBJECT_POISON
) {
892 memset(p
, POISON_FREE
, s
->object_size
- 1);
893 p
[s
->object_size
- 1] = POISON_END
;
896 if (s
->flags
& SLAB_RED_ZONE
)
897 memset(p
+ s
->object_size
, val
, s
->inuse
- s
->object_size
);
900 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
901 void *from
, void *to
)
903 slab_fix(s
, "Restoring %s 0x%p-0x%p=0x%x", message
, from
, to
- 1, data
);
904 memset(from
, data
, to
- from
);
907 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
908 u8
*object
, char *what
,
909 u8
*start
, unsigned int value
, unsigned int bytes
)
913 u8
*addr
= page_address(page
);
915 metadata_access_enable();
916 fault
= memchr_inv(kasan_reset_tag(start
), value
, bytes
);
917 metadata_access_disable();
922 while (end
> fault
&& end
[-1] == value
)
925 if (slab_add_kunit_errors())
928 slab_bug(s
, "%s overwritten", what
);
929 pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
930 fault
, end
- 1, fault
- addr
,
932 print_trailer(s
, page
, object
);
933 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
936 restore_bytes(s
, what
, value
, fault
, end
);
944 * Bytes of the object to be managed.
945 * If the freepointer may overlay the object then the free
946 * pointer is at the middle of the object.
948 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
951 * object + s->object_size
952 * Padding to reach word boundary. This is also used for Redzoning.
953 * Padding is extended by another word if Redzoning is enabled and
954 * object_size == inuse.
956 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
957 * 0xcc (RED_ACTIVE) for objects in use.
960 * Meta data starts here.
962 * A. Free pointer (if we cannot overwrite object on free)
963 * B. Tracking data for SLAB_STORE_USER
964 * C. Padding to reach required alignment boundary or at minimum
965 * one word if debugging is on to be able to detect writes
966 * before the word boundary.
968 * Padding is done using 0x5a (POISON_INUSE)
971 * Nothing is used beyond s->size.
973 * If slabcaches are merged then the object_size and inuse boundaries are mostly
974 * ignored. And therefore no slab options that rely on these boundaries
975 * may be used with merged slabcaches.
978 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
980 unsigned long off
= get_info_end(s
); /* The end of info */
982 if (s
->flags
& SLAB_STORE_USER
)
983 /* We also have user information there */
984 off
+= 2 * sizeof(struct track
);
986 off
+= kasan_metadata_size(s
);
988 if (size_from_object(s
) == off
)
991 return check_bytes_and_report(s
, page
, p
, "Object padding",
992 p
+ off
, POISON_INUSE
, size_from_object(s
) - off
);
995 /* Check the pad bytes at the end of a slab page */
996 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1005 if (!(s
->flags
& SLAB_POISON
))
1008 start
= page_address(page
);
1009 length
= page_size(page
);
1010 end
= start
+ length
;
1011 remainder
= length
% s
->size
;
1015 pad
= end
- remainder
;
1016 metadata_access_enable();
1017 fault
= memchr_inv(kasan_reset_tag(pad
), POISON_INUSE
, remainder
);
1018 metadata_access_disable();
1021 while (end
> fault
&& end
[-1] == POISON_INUSE
)
1024 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p @offset=%tu",
1025 fault
, end
- 1, fault
- start
);
1026 print_section(KERN_ERR
, "Padding ", pad
, remainder
);
1028 restore_bytes(s
, "slab padding", POISON_INUSE
, fault
, end
);
1032 static int check_object(struct kmem_cache
*s
, struct page
*page
,
1033 void *object
, u8 val
)
1036 u8
*endobject
= object
+ s
->object_size
;
1038 if (s
->flags
& SLAB_RED_ZONE
) {
1039 if (!check_bytes_and_report(s
, page
, object
, "Left Redzone",
1040 object
- s
->red_left_pad
, val
, s
->red_left_pad
))
1043 if (!check_bytes_and_report(s
, page
, object
, "Right Redzone",
1044 endobject
, val
, s
->inuse
- s
->object_size
))
1047 if ((s
->flags
& SLAB_POISON
) && s
->object_size
< s
->inuse
) {
1048 check_bytes_and_report(s
, page
, p
, "Alignment padding",
1049 endobject
, POISON_INUSE
,
1050 s
->inuse
- s
->object_size
);
1054 if (s
->flags
& SLAB_POISON
) {
1055 if (val
!= SLUB_RED_ACTIVE
&& (s
->flags
& __OBJECT_POISON
) &&
1056 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
1057 POISON_FREE
, s
->object_size
- 1) ||
1058 !check_bytes_and_report(s
, page
, p
, "End Poison",
1059 p
+ s
->object_size
- 1, POISON_END
, 1)))
1062 * check_pad_bytes cleans up on its own.
1064 check_pad_bytes(s
, page
, p
);
1067 if (!freeptr_outside_object(s
) && val
== SLUB_RED_ACTIVE
)
1069 * Object and freepointer overlap. Cannot check
1070 * freepointer while object is allocated.
1074 /* Check free pointer validity */
1075 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
1076 object_err(s
, page
, p
, "Freepointer corrupt");
1078 * No choice but to zap it and thus lose the remainder
1079 * of the free objects in this slab. May cause
1080 * another error because the object count is now wrong.
1082 set_freepointer(s
, p
, NULL
);
1088 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
1092 if (!PageSlab(page
)) {
1093 slab_err(s
, page
, "Not a valid slab page");
1097 maxobj
= order_objects(compound_order(page
), s
->size
);
1098 if (page
->objects
> maxobj
) {
1099 slab_err(s
, page
, "objects %u > max %u",
1100 page
->objects
, maxobj
);
1103 if (page
->inuse
> page
->objects
) {
1104 slab_err(s
, page
, "inuse %u > max %u",
1105 page
->inuse
, page
->objects
);
1108 /* Slab_pad_check fixes things up after itself */
1109 slab_pad_check(s
, page
);
1114 * Determine if a certain object on a page is on the freelist. Must hold the
1115 * slab lock to guarantee that the chains are in a consistent state.
1117 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
1121 void *object
= NULL
;
1124 fp
= page
->freelist
;
1125 while (fp
&& nr
<= page
->objects
) {
1128 if (!check_valid_pointer(s
, page
, fp
)) {
1130 object_err(s
, page
, object
,
1131 "Freechain corrupt");
1132 set_freepointer(s
, object
, NULL
);
1134 slab_err(s
, page
, "Freepointer corrupt");
1135 page
->freelist
= NULL
;
1136 page
->inuse
= page
->objects
;
1137 slab_fix(s
, "Freelist cleared");
1143 fp
= get_freepointer(s
, object
);
1147 max_objects
= order_objects(compound_order(page
), s
->size
);
1148 if (max_objects
> MAX_OBJS_PER_PAGE
)
1149 max_objects
= MAX_OBJS_PER_PAGE
;
1151 if (page
->objects
!= max_objects
) {
1152 slab_err(s
, page
, "Wrong number of objects. Found %d but should be %d",
1153 page
->objects
, max_objects
);
1154 page
->objects
= max_objects
;
1155 slab_fix(s
, "Number of objects adjusted");
1157 if (page
->inuse
!= page
->objects
- nr
) {
1158 slab_err(s
, page
, "Wrong object count. Counter is %d but counted were %d",
1159 page
->inuse
, page
->objects
- nr
);
1160 page
->inuse
= page
->objects
- nr
;
1161 slab_fix(s
, "Object count adjusted");
1163 return search
== NULL
;
1166 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
,
1169 if (s
->flags
& SLAB_TRACE
) {
1170 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1172 alloc
? "alloc" : "free",
1173 object
, page
->inuse
,
1177 print_section(KERN_INFO
, "Object ", (void *)object
,
1185 * Tracking of fully allocated slabs for debugging purposes.
1187 static void add_full(struct kmem_cache
*s
,
1188 struct kmem_cache_node
*n
, struct page
*page
)
1190 if (!(s
->flags
& SLAB_STORE_USER
))
1193 lockdep_assert_held(&n
->list_lock
);
1194 list_add(&page
->slab_list
, &n
->full
);
1197 static void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
, struct page
*page
)
1199 if (!(s
->flags
& SLAB_STORE_USER
))
1202 lockdep_assert_held(&n
->list_lock
);
1203 list_del(&page
->slab_list
);
1206 /* Tracking of the number of slabs for debugging purposes */
1207 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1209 struct kmem_cache_node
*n
= get_node(s
, node
);
1211 return atomic_long_read(&n
->nr_slabs
);
1214 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1216 return atomic_long_read(&n
->nr_slabs
);
1219 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1221 struct kmem_cache_node
*n
= get_node(s
, node
);
1224 * May be called early in order to allocate a slab for the
1225 * kmem_cache_node structure. Solve the chicken-egg
1226 * dilemma by deferring the increment of the count during
1227 * bootstrap (see early_kmem_cache_node_alloc).
1230 atomic_long_inc(&n
->nr_slabs
);
1231 atomic_long_add(objects
, &n
->total_objects
);
1234 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1236 struct kmem_cache_node
*n
= get_node(s
, node
);
1238 atomic_long_dec(&n
->nr_slabs
);
1239 atomic_long_sub(objects
, &n
->total_objects
);
1242 /* Object debug checks for alloc/free paths */
1243 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
1246 if (!kmem_cache_debug_flags(s
, SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
))
1249 init_object(s
, object
, SLUB_RED_INACTIVE
);
1250 init_tracking(s
, object
);
1254 void setup_page_debug(struct kmem_cache
*s
, struct page
*page
, void *addr
)
1256 if (!kmem_cache_debug_flags(s
, SLAB_POISON
))
1259 metadata_access_enable();
1260 memset(kasan_reset_tag(addr
), POISON_INUSE
, page_size(page
));
1261 metadata_access_disable();
1264 static inline int alloc_consistency_checks(struct kmem_cache
*s
,
1265 struct page
*page
, void *object
)
1267 if (!check_slab(s
, page
))
1270 if (!check_valid_pointer(s
, page
, object
)) {
1271 object_err(s
, page
, object
, "Freelist Pointer check fails");
1275 if (!check_object(s
, page
, object
, SLUB_RED_INACTIVE
))
1281 static noinline
int alloc_debug_processing(struct kmem_cache
*s
,
1283 void *object
, unsigned long addr
)
1285 if (s
->flags
& SLAB_CONSISTENCY_CHECKS
) {
1286 if (!alloc_consistency_checks(s
, page
, object
))
1290 /* Success perform special debug activities for allocs */
1291 if (s
->flags
& SLAB_STORE_USER
)
1292 set_track(s
, object
, TRACK_ALLOC
, addr
);
1293 trace(s
, page
, object
, 1);
1294 init_object(s
, object
, SLUB_RED_ACTIVE
);
1298 if (PageSlab(page
)) {
1300 * If this is a slab page then lets do the best we can
1301 * to avoid issues in the future. Marking all objects
1302 * as used avoids touching the remaining objects.
1304 slab_fix(s
, "Marking all objects used");
1305 page
->inuse
= page
->objects
;
1306 page
->freelist
= NULL
;
1311 static inline int free_consistency_checks(struct kmem_cache
*s
,
1312 struct page
*page
, void *object
, unsigned long addr
)
1314 if (!check_valid_pointer(s
, page
, object
)) {
1315 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
1319 if (on_freelist(s
, page
, object
)) {
1320 object_err(s
, page
, object
, "Object already free");
1324 if (!check_object(s
, page
, object
, SLUB_RED_ACTIVE
))
1327 if (unlikely(s
!= page
->slab_cache
)) {
1328 if (!PageSlab(page
)) {
1329 slab_err(s
, page
, "Attempt to free object(0x%p) outside of slab",
1331 } else if (!page
->slab_cache
) {
1332 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1336 object_err(s
, page
, object
,
1337 "page slab pointer corrupt.");
1343 /* Supports checking bulk free of a constructed freelist */
1344 static noinline
int free_debug_processing(
1345 struct kmem_cache
*s
, struct page
*page
,
1346 void *head
, void *tail
, int bulk_cnt
,
1349 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1350 void *object
= head
;
1352 unsigned long flags
, flags2
;
1355 spin_lock_irqsave(&n
->list_lock
, flags
);
1356 slab_lock(page
, &flags2
);
1358 if (s
->flags
& SLAB_CONSISTENCY_CHECKS
) {
1359 if (!check_slab(s
, page
))
1366 if (s
->flags
& SLAB_CONSISTENCY_CHECKS
) {
1367 if (!free_consistency_checks(s
, page
, object
, addr
))
1371 if (s
->flags
& SLAB_STORE_USER
)
1372 set_track(s
, object
, TRACK_FREE
, addr
);
1373 trace(s
, page
, object
, 0);
1374 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1375 init_object(s
, object
, SLUB_RED_INACTIVE
);
1377 /* Reached end of constructed freelist yet? */
1378 if (object
!= tail
) {
1379 object
= get_freepointer(s
, object
);
1385 if (cnt
!= bulk_cnt
)
1386 slab_err(s
, page
, "Bulk freelist count(%d) invalid(%d)\n",
1389 slab_unlock(page
, &flags2
);
1390 spin_unlock_irqrestore(&n
->list_lock
, flags
);
1392 slab_fix(s
, "Object at 0x%p not freed", object
);
1397 * Parse a block of slub_debug options. Blocks are delimited by ';'
1399 * @str: start of block
1400 * @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1401 * @slabs: return start of list of slabs, or NULL when there's no list
1402 * @init: assume this is initial parsing and not per-kmem-create parsing
1404 * returns the start of next block if there's any, or NULL
1407 parse_slub_debug_flags(char *str
, slab_flags_t
*flags
, char **slabs
, bool init
)
1409 bool higher_order_disable
= false;
1411 /* Skip any completely empty blocks */
1412 while (*str
&& *str
== ';')
1417 * No options but restriction on slabs. This means full
1418 * debugging for slabs matching a pattern.
1420 *flags
= DEBUG_DEFAULT_FLAGS
;
1425 /* Determine which debug features should be switched on */
1426 for (; *str
&& *str
!= ',' && *str
!= ';'; str
++) {
1427 switch (tolower(*str
)) {
1432 *flags
|= SLAB_CONSISTENCY_CHECKS
;
1435 *flags
|= SLAB_RED_ZONE
;
1438 *flags
|= SLAB_POISON
;
1441 *flags
|= SLAB_STORE_USER
;
1444 *flags
|= SLAB_TRACE
;
1447 *flags
|= SLAB_FAILSLAB
;
1451 * Avoid enabling debugging on caches if its minimum
1452 * order would increase as a result.
1454 higher_order_disable
= true;
1458 pr_err("slub_debug option '%c' unknown. skipped\n", *str
);
1467 /* Skip over the slab list */
1468 while (*str
&& *str
!= ';')
1471 /* Skip any completely empty blocks */
1472 while (*str
&& *str
== ';')
1475 if (init
&& higher_order_disable
)
1476 disable_higher_order_debug
= 1;
1484 static int __init
setup_slub_debug(char *str
)
1487 slab_flags_t global_flags
;
1490 bool global_slub_debug_changed
= false;
1491 bool slab_list_specified
= false;
1493 global_flags
= DEBUG_DEFAULT_FLAGS
;
1494 if (*str
++ != '=' || !*str
)
1496 * No options specified. Switch on full debugging.
1502 str
= parse_slub_debug_flags(str
, &flags
, &slab_list
, true);
1505 global_flags
= flags
;
1506 global_slub_debug_changed
= true;
1508 slab_list_specified
= true;
1513 * For backwards compatibility, a single list of flags with list of
1514 * slabs means debugging is only changed for those slabs, so the global
1515 * slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
1516 * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
1517 * long as there is no option specifying flags without a slab list.
1519 if (slab_list_specified
) {
1520 if (!global_slub_debug_changed
)
1521 global_flags
= slub_debug
;
1522 slub_debug_string
= saved_str
;
1525 slub_debug
= global_flags
;
1526 if (slub_debug
!= 0 || slub_debug_string
)
1527 static_branch_enable(&slub_debug_enabled
);
1529 static_branch_disable(&slub_debug_enabled
);
1530 if ((static_branch_unlikely(&init_on_alloc
) ||
1531 static_branch_unlikely(&init_on_free
)) &&
1532 (slub_debug
& SLAB_POISON
))
1533 pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1537 __setup("slub_debug", setup_slub_debug
);
1540 * kmem_cache_flags - apply debugging options to the cache
1541 * @object_size: the size of an object without meta data
1542 * @flags: flags to set
1543 * @name: name of the cache
1545 * Debug option(s) are applied to @flags. In addition to the debug
1546 * option(s), if a slab name (or multiple) is specified i.e.
1547 * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1548 * then only the select slabs will receive the debug option(s).
1550 slab_flags_t
kmem_cache_flags(unsigned int object_size
,
1551 slab_flags_t flags
, const char *name
)
1556 slab_flags_t block_flags
;
1557 slab_flags_t slub_debug_local
= slub_debug
;
1560 * If the slab cache is for debugging (e.g. kmemleak) then
1561 * don't store user (stack trace) information by default,
1562 * but let the user enable it via the command line below.
1564 if (flags
& SLAB_NOLEAKTRACE
)
1565 slub_debug_local
&= ~SLAB_STORE_USER
;
1568 next_block
= slub_debug_string
;
1569 /* Go through all blocks of debug options, see if any matches our slab's name */
1570 while (next_block
) {
1571 next_block
= parse_slub_debug_flags(next_block
, &block_flags
, &iter
, false);
1574 /* Found a block that has a slab list, search it */
1579 end
= strchrnul(iter
, ',');
1580 if (next_block
&& next_block
< end
)
1581 end
= next_block
- 1;
1583 glob
= strnchr(iter
, end
- iter
, '*');
1585 cmplen
= glob
- iter
;
1587 cmplen
= max_t(size_t, len
, (end
- iter
));
1589 if (!strncmp(name
, iter
, cmplen
)) {
1590 flags
|= block_flags
;
1594 if (!*end
|| *end
== ';')
1600 return flags
| slub_debug_local
;
1602 #else /* !CONFIG_SLUB_DEBUG */
1603 static inline void setup_object_debug(struct kmem_cache
*s
,
1604 struct page
*page
, void *object
) {}
1606 void setup_page_debug(struct kmem_cache
*s
, struct page
*page
, void *addr
) {}
1608 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1609 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1611 static inline int free_debug_processing(
1612 struct kmem_cache
*s
, struct page
*page
,
1613 void *head
, void *tail
, int bulk_cnt
,
1614 unsigned long addr
) { return 0; }
1616 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1618 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1619 void *object
, u8 val
) { return 1; }
1620 static inline void add_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1621 struct page
*page
) {}
1622 static inline void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1623 struct page
*page
) {}
1624 slab_flags_t
kmem_cache_flags(unsigned int object_size
,
1625 slab_flags_t flags
, const char *name
)
1629 #define slub_debug 0
1631 #define disable_higher_order_debug 0
1633 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1635 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1637 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
,
1639 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
,
1642 static bool freelist_corrupted(struct kmem_cache
*s
, struct page
*page
,
1643 void **freelist
, void *nextfree
)
1647 #endif /* CONFIG_SLUB_DEBUG */
1650 * Hooks for other subsystems that check memory allocations. In a typical
1651 * production configuration these hooks all should produce no code at all.
1653 static inline void *kmalloc_large_node_hook(void *ptr
, size_t size
, gfp_t flags
)
1655 ptr
= kasan_kmalloc_large(ptr
, size
, flags
);
1656 /* As ptr might get tagged, call kmemleak hook after KASAN. */
1657 kmemleak_alloc(ptr
, size
, 1, flags
);
1661 static __always_inline
void kfree_hook(void *x
)
1664 kasan_kfree_large(x
);
1667 static __always_inline
bool slab_free_hook(struct kmem_cache
*s
,
1670 kmemleak_free_recursive(x
, s
->flags
);
1672 debug_check_no_locks_freed(x
, s
->object_size
);
1674 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
1675 debug_check_no_obj_freed(x
, s
->object_size
);
1677 /* Use KCSAN to help debug racy use-after-free. */
1678 if (!(s
->flags
& SLAB_TYPESAFE_BY_RCU
))
1679 __kcsan_check_access(x
, s
->object_size
,
1680 KCSAN_ACCESS_WRITE
| KCSAN_ACCESS_ASSERT
);
1683 * As memory initialization might be integrated into KASAN,
1684 * kasan_slab_free and initialization memset's must be
1685 * kept together to avoid discrepancies in behavior.
1687 * The initialization memset's clear the object and the metadata,
1688 * but don't touch the SLAB redzone.
1693 if (!kasan_has_integrated_init())
1694 memset(kasan_reset_tag(x
), 0, s
->object_size
);
1695 rsize
= (s
->flags
& SLAB_RED_ZONE
) ? s
->red_left_pad
: 0;
1696 memset((char *)kasan_reset_tag(x
) + s
->inuse
, 0,
1697 s
->size
- s
->inuse
- rsize
);
1699 /* KASAN might put x into memory quarantine, delaying its reuse. */
1700 return kasan_slab_free(s
, x
, init
);
1703 static inline bool slab_free_freelist_hook(struct kmem_cache
*s
,
1704 void **head
, void **tail
,
1710 void *old_tail
= *tail
? *tail
: *head
;
1712 if (is_kfence_address(next
)) {
1713 slab_free_hook(s
, next
, false);
1717 /* Head and tail of the reconstructed freelist */
1723 next
= get_freepointer(s
, object
);
1725 /* If object's reuse doesn't have to be delayed */
1726 if (!slab_free_hook(s
, object
, slab_want_init_on_free(s
))) {
1727 /* Move object to the new freelist */
1728 set_freepointer(s
, object
, *head
);
1734 * Adjust the reconstructed freelist depth
1735 * accordingly if object's reuse is delayed.
1739 } while (object
!= old_tail
);
1744 return *head
!= NULL
;
1747 static void *setup_object(struct kmem_cache
*s
, struct page
*page
,
1750 setup_object_debug(s
, page
, object
);
1751 object
= kasan_init_slab_obj(s
, object
);
1752 if (unlikely(s
->ctor
)) {
1753 kasan_unpoison_object_data(s
, object
);
1755 kasan_poison_object_data(s
, object
);
1761 * Slab allocation and freeing
1763 static inline struct page
*alloc_slab_page(struct kmem_cache
*s
,
1764 gfp_t flags
, int node
, struct kmem_cache_order_objects oo
)
1767 unsigned int order
= oo_order(oo
);
1769 if (node
== NUMA_NO_NODE
)
1770 page
= alloc_pages(flags
, order
);
1772 page
= __alloc_pages_node(node
, flags
, order
);
1777 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1778 /* Pre-initialize the random sequence cache */
1779 static int init_cache_random_seq(struct kmem_cache
*s
)
1781 unsigned int count
= oo_objects(s
->oo
);
1784 /* Bailout if already initialised */
1788 err
= cache_random_seq_create(s
, count
, GFP_KERNEL
);
1790 pr_err("SLUB: Unable to initialize free list for %s\n",
1795 /* Transform to an offset on the set of pages */
1796 if (s
->random_seq
) {
1799 for (i
= 0; i
< count
; i
++)
1800 s
->random_seq
[i
] *= s
->size
;
1805 /* Initialize each random sequence freelist per cache */
1806 static void __init
init_freelist_randomization(void)
1808 struct kmem_cache
*s
;
1810 mutex_lock(&slab_mutex
);
1812 list_for_each_entry(s
, &slab_caches
, list
)
1813 init_cache_random_seq(s
);
1815 mutex_unlock(&slab_mutex
);
1818 /* Get the next entry on the pre-computed freelist randomized */
1819 static void *next_freelist_entry(struct kmem_cache
*s
, struct page
*page
,
1820 unsigned long *pos
, void *start
,
1821 unsigned long page_limit
,
1822 unsigned long freelist_count
)
1827 * If the target page allocation failed, the number of objects on the
1828 * page might be smaller than the usual size defined by the cache.
1831 idx
= s
->random_seq
[*pos
];
1833 if (*pos
>= freelist_count
)
1835 } while (unlikely(idx
>= page_limit
));
1837 return (char *)start
+ idx
;
1840 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1841 static bool shuffle_freelist(struct kmem_cache
*s
, struct page
*page
)
1846 unsigned long idx
, pos
, page_limit
, freelist_count
;
1848 if (page
->objects
< 2 || !s
->random_seq
)
1851 freelist_count
= oo_objects(s
->oo
);
1852 pos
= get_random_int() % freelist_count
;
1854 page_limit
= page
->objects
* s
->size
;
1855 start
= fixup_red_left(s
, page_address(page
));
1857 /* First entry is used as the base of the freelist */
1858 cur
= next_freelist_entry(s
, page
, &pos
, start
, page_limit
,
1860 cur
= setup_object(s
, page
, cur
);
1861 page
->freelist
= cur
;
1863 for (idx
= 1; idx
< page
->objects
; idx
++) {
1864 next
= next_freelist_entry(s
, page
, &pos
, start
, page_limit
,
1866 next
= setup_object(s
, page
, next
);
1867 set_freepointer(s
, cur
, next
);
1870 set_freepointer(s
, cur
, NULL
);
1875 static inline int init_cache_random_seq(struct kmem_cache
*s
)
1879 static inline void init_freelist_randomization(void) { }
1880 static inline bool shuffle_freelist(struct kmem_cache
*s
, struct page
*page
)
1884 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1886 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1889 struct kmem_cache_order_objects oo
= s
->oo
;
1891 void *start
, *p
, *next
;
1895 flags
&= gfp_allowed_mask
;
1897 flags
|= s
->allocflags
;
1900 * Let the initial higher-order allocation fail under memory pressure
1901 * so we fall-back to the minimum order allocation.
1903 alloc_gfp
= (flags
| __GFP_NOWARN
| __GFP_NORETRY
) & ~__GFP_NOFAIL
;
1904 if ((alloc_gfp
& __GFP_DIRECT_RECLAIM
) && oo_order(oo
) > oo_order(s
->min
))
1905 alloc_gfp
= (alloc_gfp
| __GFP_NOMEMALLOC
) & ~(__GFP_RECLAIM
|__GFP_NOFAIL
);
1907 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1908 if (unlikely(!page
)) {
1912 * Allocation may have failed due to fragmentation.
1913 * Try a lower order alloc if possible
1915 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1916 if (unlikely(!page
))
1918 stat(s
, ORDER_FALLBACK
);
1921 page
->objects
= oo_objects(oo
);
1923 account_slab_page(page
, oo_order(oo
), s
, flags
);
1925 page
->slab_cache
= s
;
1926 __SetPageSlab(page
);
1927 if (page_is_pfmemalloc(page
))
1928 SetPageSlabPfmemalloc(page
);
1930 kasan_poison_slab(page
);
1932 start
= page_address(page
);
1934 setup_page_debug(s
, page
, start
);
1936 shuffle
= shuffle_freelist(s
, page
);
1939 start
= fixup_red_left(s
, start
);
1940 start
= setup_object(s
, page
, start
);
1941 page
->freelist
= start
;
1942 for (idx
= 0, p
= start
; idx
< page
->objects
- 1; idx
++) {
1944 next
= setup_object(s
, page
, next
);
1945 set_freepointer(s
, p
, next
);
1948 set_freepointer(s
, p
, NULL
);
1951 page
->inuse
= page
->objects
;
1958 inc_slabs_node(s
, page_to_nid(page
), page
->objects
);
1963 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1965 if (unlikely(flags
& GFP_SLAB_BUG_MASK
))
1966 flags
= kmalloc_fix_flags(flags
);
1968 WARN_ON_ONCE(s
->ctor
&& (flags
& __GFP_ZERO
));
1970 return allocate_slab(s
,
1971 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1974 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1976 int order
= compound_order(page
);
1977 int pages
= 1 << order
;
1979 if (kmem_cache_debug_flags(s
, SLAB_CONSISTENCY_CHECKS
)) {
1982 slab_pad_check(s
, page
);
1983 for_each_object(p
, s
, page_address(page
),
1985 check_object(s
, page
, p
, SLUB_RED_INACTIVE
);
1988 __ClearPageSlabPfmemalloc(page
);
1989 __ClearPageSlab(page
);
1990 /* In union with page->mapping where page allocator expects NULL */
1991 page
->slab_cache
= NULL
;
1992 if (current
->reclaim_state
)
1993 current
->reclaim_state
->reclaimed_slab
+= pages
;
1994 unaccount_slab_page(page
, order
, s
);
1995 __free_pages(page
, order
);
1998 static void rcu_free_slab(struct rcu_head
*h
)
2000 struct page
*page
= container_of(h
, struct page
, rcu_head
);
2002 __free_slab(page
->slab_cache
, page
);
2005 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
2007 if (unlikely(s
->flags
& SLAB_TYPESAFE_BY_RCU
)) {
2008 call_rcu(&page
->rcu_head
, rcu_free_slab
);
2010 __free_slab(s
, page
);
2013 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
2015 dec_slabs_node(s
, page_to_nid(page
), page
->objects
);
2020 * Management of partially allocated slabs.
2023 __add_partial(struct kmem_cache_node
*n
, struct page
*page
, int tail
)
2026 if (tail
== DEACTIVATE_TO_TAIL
)
2027 list_add_tail(&page
->slab_list
, &n
->partial
);
2029 list_add(&page
->slab_list
, &n
->partial
);
2032 static inline void add_partial(struct kmem_cache_node
*n
,
2033 struct page
*page
, int tail
)
2035 lockdep_assert_held(&n
->list_lock
);
2036 __add_partial(n
, page
, tail
);
2039 static inline void remove_partial(struct kmem_cache_node
*n
,
2042 lockdep_assert_held(&n
->list_lock
);
2043 list_del(&page
->slab_list
);
2048 * Remove slab from the partial list, freeze it and
2049 * return the pointer to the freelist.
2051 * Returns a list of objects or NULL if it fails.
2053 static inline void *acquire_slab(struct kmem_cache
*s
,
2054 struct kmem_cache_node
*n
, struct page
*page
,
2055 int mode
, int *objects
)
2058 unsigned long counters
;
2061 lockdep_assert_held(&n
->list_lock
);
2064 * Zap the freelist and set the frozen bit.
2065 * The old freelist is the list of objects for the
2066 * per cpu allocation list.
2068 freelist
= page
->freelist
;
2069 counters
= page
->counters
;
2070 new.counters
= counters
;
2071 *objects
= new.objects
- new.inuse
;
2073 new.inuse
= page
->objects
;
2074 new.freelist
= NULL
;
2076 new.freelist
= freelist
;
2079 VM_BUG_ON(new.frozen
);
2082 if (!__cmpxchg_double_slab(s
, page
,
2084 new.freelist
, new.counters
,
2088 remove_partial(n
, page
);
2093 #ifdef CONFIG_SLUB_CPU_PARTIAL
2094 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
);
2096 static inline void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
,
2099 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
);
2102 * Try to allocate a partial slab from a specific node.
2104 static void *get_partial_node(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
2105 struct page
**ret_page
, gfp_t gfpflags
)
2107 struct page
*page
, *page2
;
2108 void *object
= NULL
;
2109 unsigned int available
= 0;
2110 unsigned long flags
;
2114 * Racy check. If we mistakenly see no partial slabs then we
2115 * just allocate an empty slab. If we mistakenly try to get a
2116 * partial slab and there is none available then get_partial()
2119 if (!n
|| !n
->nr_partial
)
2122 spin_lock_irqsave(&n
->list_lock
, flags
);
2123 list_for_each_entry_safe(page
, page2
, &n
->partial
, slab_list
) {
2126 if (!pfmemalloc_match(page
, gfpflags
))
2129 t
= acquire_slab(s
, n
, page
, object
== NULL
, &objects
);
2133 available
+= objects
;
2136 stat(s
, ALLOC_FROM_PARTIAL
);
2139 put_cpu_partial(s
, page
, 0);
2140 stat(s
, CPU_PARTIAL_NODE
);
2142 if (!kmem_cache_has_cpu_partial(s
)
2143 || available
> slub_cpu_partial(s
) / 2)
2147 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2152 * Get a page from somewhere. Search in increasing NUMA distances.
2154 static void *get_any_partial(struct kmem_cache
*s
, gfp_t flags
,
2155 struct page
**ret_page
)
2158 struct zonelist
*zonelist
;
2161 enum zone_type highest_zoneidx
= gfp_zone(flags
);
2163 unsigned int cpuset_mems_cookie
;
2166 * The defrag ratio allows a configuration of the tradeoffs between
2167 * inter node defragmentation and node local allocations. A lower
2168 * defrag_ratio increases the tendency to do local allocations
2169 * instead of attempting to obtain partial slabs from other nodes.
2171 * If the defrag_ratio is set to 0 then kmalloc() always
2172 * returns node local objects. If the ratio is higher then kmalloc()
2173 * may return off node objects because partial slabs are obtained
2174 * from other nodes and filled up.
2176 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2177 * (which makes defrag_ratio = 1000) then every (well almost)
2178 * allocation will first attempt to defrag slab caches on other nodes.
2179 * This means scanning over all nodes to look for partial slabs which
2180 * may be expensive if we do it every time we are trying to find a slab
2181 * with available objects.
2183 if (!s
->remote_node_defrag_ratio
||
2184 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
2188 cpuset_mems_cookie
= read_mems_allowed_begin();
2189 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
2190 for_each_zone_zonelist(zone
, z
, zonelist
, highest_zoneidx
) {
2191 struct kmem_cache_node
*n
;
2193 n
= get_node(s
, zone_to_nid(zone
));
2195 if (n
&& cpuset_zone_allowed(zone
, flags
) &&
2196 n
->nr_partial
> s
->min_partial
) {
2197 object
= get_partial_node(s
, n
, ret_page
, flags
);
2200 * Don't check read_mems_allowed_retry()
2201 * here - if mems_allowed was updated in
2202 * parallel, that was a harmless race
2203 * between allocation and the cpuset
2210 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
2211 #endif /* CONFIG_NUMA */
2216 * Get a partial page, lock it and return it.
2218 static void *get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
,
2219 struct page
**ret_page
)
2222 int searchnode
= node
;
2224 if (node
== NUMA_NO_NODE
)
2225 searchnode
= numa_mem_id();
2227 object
= get_partial_node(s
, get_node(s
, searchnode
), ret_page
, flags
);
2228 if (object
|| node
!= NUMA_NO_NODE
)
2231 return get_any_partial(s
, flags
, ret_page
);
2234 #ifdef CONFIG_PREEMPTION
2236 * Calculate the next globally unique transaction for disambiguation
2237 * during cmpxchg. The transactions start with the cpu number and are then
2238 * incremented by CONFIG_NR_CPUS.
2240 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
2243 * No preemption supported therefore also no need to check for
2249 static inline unsigned long next_tid(unsigned long tid
)
2251 return tid
+ TID_STEP
;
2254 #ifdef SLUB_DEBUG_CMPXCHG
2255 static inline unsigned int tid_to_cpu(unsigned long tid
)
2257 return tid
% TID_STEP
;
2260 static inline unsigned long tid_to_event(unsigned long tid
)
2262 return tid
/ TID_STEP
;
2266 static inline unsigned int init_tid(int cpu
)
2271 static inline void note_cmpxchg_failure(const char *n
,
2272 const struct kmem_cache
*s
, unsigned long tid
)
2274 #ifdef SLUB_DEBUG_CMPXCHG
2275 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
2277 pr_info("%s %s: cmpxchg redo ", n
, s
->name
);
2279 #ifdef CONFIG_PREEMPTION
2280 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
2281 pr_warn("due to cpu change %d -> %d\n",
2282 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
2285 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
2286 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2287 tid_to_event(tid
), tid_to_event(actual_tid
));
2289 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2290 actual_tid
, tid
, next_tid(tid
));
2292 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
2295 static void init_kmem_cache_cpus(struct kmem_cache
*s
)
2298 struct kmem_cache_cpu
*c
;
2300 for_each_possible_cpu(cpu
) {
2301 c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2302 local_lock_init(&c
->lock
);
2303 c
->tid
= init_tid(cpu
);
2308 * Finishes removing the cpu slab. Merges cpu's freelist with page's freelist,
2309 * unfreezes the slabs and puts it on the proper list.
2310 * Assumes the slab has been already safely taken away from kmem_cache_cpu
2313 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
,
2316 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
2317 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
2318 int lock
= 0, free_delta
= 0;
2319 enum slab_modes l
= M_NONE
, m
= M_NONE
;
2320 void *nextfree
, *freelist_iter
, *freelist_tail
;
2321 int tail
= DEACTIVATE_TO_HEAD
;
2322 unsigned long flags
= 0;
2326 if (page
->freelist
) {
2327 stat(s
, DEACTIVATE_REMOTE_FREES
);
2328 tail
= DEACTIVATE_TO_TAIL
;
2332 * Stage one: Count the objects on cpu's freelist as free_delta and
2333 * remember the last object in freelist_tail for later splicing.
2335 freelist_tail
= NULL
;
2336 freelist_iter
= freelist
;
2337 while (freelist_iter
) {
2338 nextfree
= get_freepointer(s
, freelist_iter
);
2341 * If 'nextfree' is invalid, it is possible that the object at
2342 * 'freelist_iter' is already corrupted. So isolate all objects
2343 * starting at 'freelist_iter' by skipping them.
2345 if (freelist_corrupted(s
, page
, &freelist_iter
, nextfree
))
2348 freelist_tail
= freelist_iter
;
2351 freelist_iter
= nextfree
;
2355 * Stage two: Unfreeze the page while splicing the per-cpu
2356 * freelist to the head of page's freelist.
2358 * Ensure that the page is unfrozen while the list presence
2359 * reflects the actual number of objects during unfreeze.
2361 * We setup the list membership and then perform a cmpxchg
2362 * with the count. If there is a mismatch then the page
2363 * is not unfrozen but the page is on the wrong list.
2365 * Then we restart the process which may have to remove
2366 * the page from the list that we just put it on again
2367 * because the number of objects in the slab may have
2372 old
.freelist
= READ_ONCE(page
->freelist
);
2373 old
.counters
= READ_ONCE(page
->counters
);
2374 VM_BUG_ON(!old
.frozen
);
2376 /* Determine target state of the slab */
2377 new.counters
= old
.counters
;
2378 if (freelist_tail
) {
2379 new.inuse
-= free_delta
;
2380 set_freepointer(s
, freelist_tail
, old
.freelist
);
2381 new.freelist
= freelist
;
2383 new.freelist
= old
.freelist
;
2387 if (!new.inuse
&& n
->nr_partial
>= s
->min_partial
)
2389 else if (new.freelist
) {
2394 * Taking the spinlock removes the possibility
2395 * that acquire_slab() will see a slab page that
2398 spin_lock_irqsave(&n
->list_lock
, flags
);
2402 if (kmem_cache_debug_flags(s
, SLAB_STORE_USER
) && !lock
) {
2405 * This also ensures that the scanning of full
2406 * slabs from diagnostic functions will not see
2409 spin_lock_irqsave(&n
->list_lock
, flags
);
2415 remove_partial(n
, page
);
2416 else if (l
== M_FULL
)
2417 remove_full(s
, n
, page
);
2420 add_partial(n
, page
, tail
);
2421 else if (m
== M_FULL
)
2422 add_full(s
, n
, page
);
2426 if (!cmpxchg_double_slab(s
, page
,
2427 old
.freelist
, old
.counters
,
2428 new.freelist
, new.counters
,
2433 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2437 else if (m
== M_FULL
)
2438 stat(s
, DEACTIVATE_FULL
);
2439 else if (m
== M_FREE
) {
2440 stat(s
, DEACTIVATE_EMPTY
);
2441 discard_slab(s
, page
);
2446 #ifdef CONFIG_SLUB_CPU_PARTIAL
2447 static void __unfreeze_partials(struct kmem_cache
*s
, struct page
*partial_page
)
2449 struct kmem_cache_node
*n
= NULL
, *n2
= NULL
;
2450 struct page
*page
, *discard_page
= NULL
;
2451 unsigned long flags
= 0;
2453 while (partial_page
) {
2457 page
= partial_page
;
2458 partial_page
= page
->next
;
2460 n2
= get_node(s
, page_to_nid(page
));
2463 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2466 spin_lock_irqsave(&n
->list_lock
, flags
);
2471 old
.freelist
= page
->freelist
;
2472 old
.counters
= page
->counters
;
2473 VM_BUG_ON(!old
.frozen
);
2475 new.counters
= old
.counters
;
2476 new.freelist
= old
.freelist
;
2480 } while (!__cmpxchg_double_slab(s
, page
,
2481 old
.freelist
, old
.counters
,
2482 new.freelist
, new.counters
,
2483 "unfreezing slab"));
2485 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
)) {
2486 page
->next
= discard_page
;
2487 discard_page
= page
;
2489 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2490 stat(s
, FREE_ADD_PARTIAL
);
2495 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2497 while (discard_page
) {
2498 page
= discard_page
;
2499 discard_page
= discard_page
->next
;
2501 stat(s
, DEACTIVATE_EMPTY
);
2502 discard_slab(s
, page
);
2508 * Unfreeze all the cpu partial slabs.
2510 static void unfreeze_partials(struct kmem_cache
*s
)
2512 struct page
*partial_page
;
2513 unsigned long flags
;
2515 local_lock_irqsave(&s
->cpu_slab
->lock
, flags
);
2516 partial_page
= this_cpu_read(s
->cpu_slab
->partial
);
2517 this_cpu_write(s
->cpu_slab
->partial
, NULL
);
2518 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2521 __unfreeze_partials(s
, partial_page
);
2524 static void unfreeze_partials_cpu(struct kmem_cache
*s
,
2525 struct kmem_cache_cpu
*c
)
2527 struct page
*partial_page
;
2529 partial_page
= slub_percpu_partial(c
);
2533 __unfreeze_partials(s
, partial_page
);
2537 * Put a page that was just frozen (in __slab_free|get_partial_node) into a
2538 * partial page slot if available.
2540 * If we did not find a slot then simply move all the partials to the
2541 * per node partial list.
2543 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
)
2545 struct page
*oldpage
;
2546 struct page
*page_to_unfreeze
= NULL
;
2547 unsigned long flags
;
2551 local_lock_irqsave(&s
->cpu_slab
->lock
, flags
);
2553 oldpage
= this_cpu_read(s
->cpu_slab
->partial
);
2556 if (drain
&& oldpage
->pobjects
> slub_cpu_partial(s
)) {
2558 * Partial array is full. Move the existing set to the
2559 * per node partial list. Postpone the actual unfreezing
2560 * outside of the critical section.
2562 page_to_unfreeze
= oldpage
;
2565 pobjects
= oldpage
->pobjects
;
2566 pages
= oldpage
->pages
;
2571 pobjects
+= page
->objects
- page
->inuse
;
2573 page
->pages
= pages
;
2574 page
->pobjects
= pobjects
;
2575 page
->next
= oldpage
;
2577 this_cpu_write(s
->cpu_slab
->partial
, page
);
2579 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2581 if (page_to_unfreeze
) {
2582 __unfreeze_partials(s
, page_to_unfreeze
);
2583 stat(s
, CPU_PARTIAL_DRAIN
);
2587 #else /* CONFIG_SLUB_CPU_PARTIAL */
2589 static inline void unfreeze_partials(struct kmem_cache
*s
) { }
2590 static inline void unfreeze_partials_cpu(struct kmem_cache
*s
,
2591 struct kmem_cache_cpu
*c
) { }
2593 #endif /* CONFIG_SLUB_CPU_PARTIAL */
2595 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
2597 unsigned long flags
;
2601 local_lock_irqsave(&s
->cpu_slab
->lock
, flags
);
2604 freelist
= c
->freelist
;
2608 c
->tid
= next_tid(c
->tid
);
2610 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2613 deactivate_slab(s
, page
, freelist
);
2614 stat(s
, CPUSLAB_FLUSH
);
2618 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
2620 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2621 void *freelist
= c
->freelist
;
2622 struct page
*page
= c
->page
;
2626 c
->tid
= next_tid(c
->tid
);
2629 deactivate_slab(s
, page
, freelist
);
2630 stat(s
, CPUSLAB_FLUSH
);
2633 unfreeze_partials_cpu(s
, c
);
2636 struct slub_flush_work
{
2637 struct work_struct work
;
2638 struct kmem_cache
*s
;
2645 * Called from CPU work handler with migration disabled.
2647 static void flush_cpu_slab(struct work_struct
*w
)
2649 struct kmem_cache
*s
;
2650 struct kmem_cache_cpu
*c
;
2651 struct slub_flush_work
*sfw
;
2653 sfw
= container_of(w
, struct slub_flush_work
, work
);
2656 c
= this_cpu_ptr(s
->cpu_slab
);
2661 unfreeze_partials(s
);
2664 static bool has_cpu_slab(int cpu
, struct kmem_cache
*s
)
2666 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2668 return c
->page
|| slub_percpu_partial(c
);
2671 static DEFINE_MUTEX(flush_lock
);
2672 static DEFINE_PER_CPU(struct slub_flush_work
, slub_flush
);
2674 static void flush_all_cpus_locked(struct kmem_cache
*s
)
2676 struct slub_flush_work
*sfw
;
2679 lockdep_assert_cpus_held();
2680 mutex_lock(&flush_lock
);
2682 for_each_online_cpu(cpu
) {
2683 sfw
= &per_cpu(slub_flush
, cpu
);
2684 if (!has_cpu_slab(cpu
, s
)) {
2688 INIT_WORK(&sfw
->work
, flush_cpu_slab
);
2691 schedule_work_on(cpu
, &sfw
->work
);
2694 for_each_online_cpu(cpu
) {
2695 sfw
= &per_cpu(slub_flush
, cpu
);
2698 flush_work(&sfw
->work
);
2701 mutex_unlock(&flush_lock
);
2704 static void flush_all(struct kmem_cache
*s
)
2707 flush_all_cpus_locked(s
);
2712 * Use the cpu notifier to insure that the cpu slabs are flushed when
2715 static int slub_cpu_dead(unsigned int cpu
)
2717 struct kmem_cache
*s
;
2719 mutex_lock(&slab_mutex
);
2720 list_for_each_entry(s
, &slab_caches
, list
)
2721 __flush_cpu_slab(s
, cpu
);
2722 mutex_unlock(&slab_mutex
);
2727 * Check if the objects in a per cpu structure fit numa
2728 * locality expectations.
2730 static inline int node_match(struct page
*page
, int node
)
2733 if (node
!= NUMA_NO_NODE
&& page_to_nid(page
) != node
)
2739 #ifdef CONFIG_SLUB_DEBUG
2740 static int count_free(struct page
*page
)
2742 return page
->objects
- page
->inuse
;
2745 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
2747 return atomic_long_read(&n
->total_objects
);
2749 #endif /* CONFIG_SLUB_DEBUG */
2751 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2752 static unsigned long count_partial(struct kmem_cache_node
*n
,
2753 int (*get_count
)(struct page
*))
2755 unsigned long flags
;
2756 unsigned long x
= 0;
2759 spin_lock_irqsave(&n
->list_lock
, flags
);
2760 list_for_each_entry(page
, &n
->partial
, slab_list
)
2761 x
+= get_count(page
);
2762 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2765 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2767 static noinline
void
2768 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
2770 #ifdef CONFIG_SLUB_DEBUG
2771 static DEFINE_RATELIMIT_STATE(slub_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2772 DEFAULT_RATELIMIT_BURST
);
2774 struct kmem_cache_node
*n
;
2776 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slub_oom_rs
))
2779 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2780 nid
, gfpflags
, &gfpflags
);
2781 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2782 s
->name
, s
->object_size
, s
->size
, oo_order(s
->oo
),
2785 if (oo_order(s
->min
) > get_order(s
->object_size
))
2786 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2789 for_each_kmem_cache_node(s
, node
, n
) {
2790 unsigned long nr_slabs
;
2791 unsigned long nr_objs
;
2792 unsigned long nr_free
;
2794 nr_free
= count_partial(n
, count_free
);
2795 nr_slabs
= node_nr_slabs(n
);
2796 nr_objs
= node_nr_objs(n
);
2798 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2799 node
, nr_slabs
, nr_objs
, nr_free
);
2804 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
)
2806 if (unlikely(PageSlabPfmemalloc(page
)))
2807 return gfp_pfmemalloc_allowed(gfpflags
);
2813 * A variant of pfmemalloc_match() that tests page flags without asserting
2814 * PageSlab. Intended for opportunistic checks before taking a lock and
2815 * rechecking that nobody else freed the page under us.
2817 static inline bool pfmemalloc_match_unsafe(struct page
*page
, gfp_t gfpflags
)
2819 if (unlikely(__PageSlabPfmemalloc(page
)))
2820 return gfp_pfmemalloc_allowed(gfpflags
);
2826 * Check the page->freelist of a page and either transfer the freelist to the
2827 * per cpu freelist or deactivate the page.
2829 * The page is still frozen if the return value is not NULL.
2831 * If this function returns NULL then the page has been unfrozen.
2833 static inline void *get_freelist(struct kmem_cache
*s
, struct page
*page
)
2836 unsigned long counters
;
2839 lockdep_assert_held(this_cpu_ptr(&s
->cpu_slab
->lock
));
2842 freelist
= page
->freelist
;
2843 counters
= page
->counters
;
2845 new.counters
= counters
;
2846 VM_BUG_ON(!new.frozen
);
2848 new.inuse
= page
->objects
;
2849 new.frozen
= freelist
!= NULL
;
2851 } while (!__cmpxchg_double_slab(s
, page
,
2860 * Slow path. The lockless freelist is empty or we need to perform
2863 * Processing is still very fast if new objects have been freed to the
2864 * regular freelist. In that case we simply take over the regular freelist
2865 * as the lockless freelist and zap the regular freelist.
2867 * If that is not working then we fall back to the partial lists. We take the
2868 * first element of the freelist as the object to allocate now and move the
2869 * rest of the freelist to the lockless freelist.
2871 * And if we were unable to get a new slab from the partial slab lists then
2872 * we need to allocate a new slab. This is the slowest path since it involves
2873 * a call to the page allocator and the setup of a new slab.
2875 * Version of __slab_alloc to use when we know that preemption is
2876 * already disabled (which is the case for bulk allocation).
2878 static void *___slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2879 unsigned long addr
, struct kmem_cache_cpu
*c
)
2883 unsigned long flags
;
2885 stat(s
, ALLOC_SLOWPATH
);
2889 page
= READ_ONCE(c
->page
);
2892 * if the node is not online or has no normal memory, just
2893 * ignore the node constraint
2895 if (unlikely(node
!= NUMA_NO_NODE
&&
2896 !node_isset(node
, slab_nodes
)))
2897 node
= NUMA_NO_NODE
;
2902 if (unlikely(!node_match(page
, node
))) {
2904 * same as above but node_match() being false already
2905 * implies node != NUMA_NO_NODE
2907 if (!node_isset(node
, slab_nodes
)) {
2908 node
= NUMA_NO_NODE
;
2911 stat(s
, ALLOC_NODE_MISMATCH
);
2912 goto deactivate_slab
;
2917 * By rights, we should be searching for a slab page that was
2918 * PFMEMALLOC but right now, we are losing the pfmemalloc
2919 * information when the page leaves the per-cpu allocator
2921 if (unlikely(!pfmemalloc_match_unsafe(page
, gfpflags
)))
2922 goto deactivate_slab
;
2924 /* must check again c->page in case we got preempted and it changed */
2925 local_lock_irqsave(&s
->cpu_slab
->lock
, flags
);
2926 if (unlikely(page
!= c
->page
)) {
2927 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2930 freelist
= c
->freelist
;
2934 freelist
= get_freelist(s
, page
);
2938 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2939 stat(s
, DEACTIVATE_BYPASS
);
2943 stat(s
, ALLOC_REFILL
);
2947 lockdep_assert_held(this_cpu_ptr(&s
->cpu_slab
->lock
));
2950 * freelist is pointing to the list of objects to be used.
2951 * page is pointing to the page from which the objects are obtained.
2952 * That page must be frozen for per cpu allocations to work.
2954 VM_BUG_ON(!c
->page
->frozen
);
2955 c
->freelist
= get_freepointer(s
, freelist
);
2956 c
->tid
= next_tid(c
->tid
);
2957 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2962 local_lock_irqsave(&s
->cpu_slab
->lock
, flags
);
2963 if (page
!= c
->page
) {
2964 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2967 freelist
= c
->freelist
;
2970 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2971 deactivate_slab(s
, page
, freelist
);
2975 if (slub_percpu_partial(c
)) {
2976 local_lock_irqsave(&s
->cpu_slab
->lock
, flags
);
2977 if (unlikely(c
->page
)) {
2978 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2981 if (unlikely(!slub_percpu_partial(c
))) {
2982 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2983 /* we were preempted and partial list got empty */
2987 page
= c
->page
= slub_percpu_partial(c
);
2988 slub_set_percpu_partial(c
, page
);
2989 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
2990 stat(s
, CPU_PARTIAL_ALLOC
);
2996 freelist
= get_partial(s
, gfpflags
, node
, &page
);
2998 goto check_new_page
;
3000 slub_put_cpu_ptr(s
->cpu_slab
);
3001 page
= new_slab(s
, gfpflags
, node
);
3002 c
= slub_get_cpu_ptr(s
->cpu_slab
);
3004 if (unlikely(!page
)) {
3005 slab_out_of_memory(s
, gfpflags
, node
);
3010 * No other reference to the page yet so we can
3011 * muck around with it freely without cmpxchg
3013 freelist
= page
->freelist
;
3014 page
->freelist
= NULL
;
3016 stat(s
, ALLOC_SLAB
);
3020 if (kmem_cache_debug(s
)) {
3021 if (!alloc_debug_processing(s
, page
, freelist
, addr
)) {
3022 /* Slab failed checks. Next slab needed */
3026 * For debug case, we don't load freelist so that all
3027 * allocations go through alloc_debug_processing()
3033 if (unlikely(!pfmemalloc_match(page
, gfpflags
)))
3035 * For !pfmemalloc_match() case we don't load freelist so that
3036 * we don't make further mismatched allocations easier.
3042 local_lock_irqsave(&s
->cpu_slab
->lock
, flags
);
3043 if (unlikely(c
->page
)) {
3044 void *flush_freelist
= c
->freelist
;
3045 struct page
*flush_page
= c
->page
;
3049 c
->tid
= next_tid(c
->tid
);
3051 local_unlock_irqrestore(&s
->cpu_slab
->lock
, flags
);
3053 deactivate_slab(s
, flush_page
, flush_freelist
);
3055 stat(s
, CPUSLAB_FLUSH
);
3057 goto retry_load_page
;
3065 deactivate_slab(s
, page
, get_freepointer(s
, freelist
));
3070 * A wrapper for ___slab_alloc() for contexts where preemption is not yet
3071 * disabled. Compensates for possible cpu changes by refetching the per cpu area
3074 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
3075 unsigned long addr
, struct kmem_cache_cpu
*c
)
3079 #ifdef CONFIG_PREEMPT_COUNT
3081 * We may have been preempted and rescheduled on a different
3082 * cpu before disabling preemption. Need to reload cpu area
3085 c
= slub_get_cpu_ptr(s
->cpu_slab
);
3088 p
= ___slab_alloc(s
, gfpflags
, node
, addr
, c
);
3089 #ifdef CONFIG_PREEMPT_COUNT
3090 slub_put_cpu_ptr(s
->cpu_slab
);
3096 * If the object has been wiped upon free, make sure it's fully initialized by
3097 * zeroing out freelist pointer.
3099 static __always_inline
void maybe_wipe_obj_freeptr(struct kmem_cache
*s
,
3102 if (unlikely(slab_want_init_on_free(s
)) && obj
)
3103 memset((void *)((char *)kasan_reset_tag(obj
) + s
->offset
),
3108 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
3109 * have the fastpath folded into their functions. So no function call
3110 * overhead for requests that can be satisfied on the fastpath.
3112 * The fastpath works by first checking if the lockless freelist can be used.
3113 * If not then __slab_alloc is called for slow processing.
3115 * Otherwise we can simply pick the next object from the lockless free list.
3117 static __always_inline
void *slab_alloc_node(struct kmem_cache
*s
,
3118 gfp_t gfpflags
, int node
, unsigned long addr
, size_t orig_size
)
3121 struct kmem_cache_cpu
*c
;
3124 struct obj_cgroup
*objcg
= NULL
;
3127 s
= slab_pre_alloc_hook(s
, &objcg
, 1, gfpflags
);
3131 object
= kfence_alloc(s
, orig_size
, gfpflags
);
3132 if (unlikely(object
))
3137 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
3138 * enabled. We may switch back and forth between cpus while
3139 * reading from one cpu area. That does not matter as long
3140 * as we end up on the original cpu again when doing the cmpxchg.
3142 * We must guarantee that tid and kmem_cache_cpu are retrieved on the
3143 * same cpu. We read first the kmem_cache_cpu pointer and use it to read
3144 * the tid. If we are preempted and switched to another cpu between the
3145 * two reads, it's OK as the two are still associated with the same cpu
3146 * and cmpxchg later will validate the cpu.
3148 c
= raw_cpu_ptr(s
->cpu_slab
);
3149 tid
= READ_ONCE(c
->tid
);
3152 * Irqless object alloc/free algorithm used here depends on sequence
3153 * of fetching cpu_slab's data. tid should be fetched before anything
3154 * on c to guarantee that object and page associated with previous tid
3155 * won't be used with current tid. If we fetch tid first, object and
3156 * page could be one associated with next tid and our alloc/free
3157 * request will be failed. In this case, we will retry. So, no problem.
3162 * The transaction ids are globally unique per cpu and per operation on
3163 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
3164 * occurs on the right processor and that there was no operation on the
3165 * linked list in between.
3168 object
= c
->freelist
;
3171 * We cannot use the lockless fastpath on PREEMPT_RT because if a
3172 * slowpath has taken the local_lock_irqsave(), it is not protected
3173 * against a fast path operation in an irq handler. So we need to take
3174 * the slow path which uses local_lock. It is still relatively fast if
3175 * there is a suitable cpu freelist.
3177 if (IS_ENABLED(CONFIG_PREEMPT_RT
) ||
3178 unlikely(!object
|| !page
|| !node_match(page
, node
))) {
3179 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
3181 void *next_object
= get_freepointer_safe(s
, object
);
3184 * The cmpxchg will only match if there was no additional
3185 * operation and if we are on the right processor.
3187 * The cmpxchg does the following atomically (without lock
3189 * 1. Relocate first pointer to the current per cpu area.
3190 * 2. Verify that tid and freelist have not been changed
3191 * 3. If they were not changed replace tid and freelist
3193 * Since this is without lock semantics the protection is only
3194 * against code executing on this cpu *not* from access by
3197 if (unlikely(!this_cpu_cmpxchg_double(
3198 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
3200 next_object
, next_tid(tid
)))) {
3202 note_cmpxchg_failure("slab_alloc", s
, tid
);
3205 prefetch_freepointer(s
, next_object
);
3206 stat(s
, ALLOC_FASTPATH
);
3209 maybe_wipe_obj_freeptr(s
, object
);
3210 init
= slab_want_init_on_alloc(gfpflags
, s
);
3213 slab_post_alloc_hook(s
, objcg
, gfpflags
, 1, &object
, init
);
3218 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
3219 gfp_t gfpflags
, unsigned long addr
, size_t orig_size
)
3221 return slab_alloc_node(s
, gfpflags
, NUMA_NO_NODE
, addr
, orig_size
);
3224 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
3226 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
, s
->object_size
);
3228 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->object_size
,
3233 EXPORT_SYMBOL(kmem_cache_alloc
);
3235 #ifdef CONFIG_TRACING
3236 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
3238 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
, size
);
3239 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
3240 ret
= kasan_kmalloc(s
, ret
, size
, gfpflags
);
3243 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
3247 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
3249 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
, s
->object_size
);
3251 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
3252 s
->object_size
, s
->size
, gfpflags
, node
);
3256 EXPORT_SYMBOL(kmem_cache_alloc_node
);
3258 #ifdef CONFIG_TRACING
3259 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
3261 int node
, size_t size
)
3263 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
, size
);
3265 trace_kmalloc_node(_RET_IP_
, ret
,
3266 size
, s
->size
, gfpflags
, node
);
3268 ret
= kasan_kmalloc(s
, ret
, size
, gfpflags
);
3271 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
3273 #endif /* CONFIG_NUMA */
3276 * Slow path handling. This may still be called frequently since objects
3277 * have a longer lifetime than the cpu slabs in most processing loads.
3279 * So we still attempt to reduce cache line usage. Just take the slab
3280 * lock and free the item. If there is no additional partial page
3281 * handling required then we can return immediately.
3283 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
3284 void *head
, void *tail
, int cnt
,
3291 unsigned long counters
;
3292 struct kmem_cache_node
*n
= NULL
;
3293 unsigned long flags
;
3295 stat(s
, FREE_SLOWPATH
);
3297 if (kfence_free(head
))
3300 if (kmem_cache_debug(s
) &&
3301 !free_debug_processing(s
, page
, head
, tail
, cnt
, addr
))
3306 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3309 prior
= page
->freelist
;
3310 counters
= page
->counters
;
3311 set_freepointer(s
, tail
, prior
);
3312 new.counters
= counters
;
3313 was_frozen
= new.frozen
;
3315 if ((!new.inuse
|| !prior
) && !was_frozen
) {
3317 if (kmem_cache_has_cpu_partial(s
) && !prior
) {
3320 * Slab was on no list before and will be
3322 * We can defer the list move and instead
3327 } else { /* Needs to be taken off a list */
3329 n
= get_node(s
, page_to_nid(page
));
3331 * Speculatively acquire the list_lock.
3332 * If the cmpxchg does not succeed then we may
3333 * drop the list_lock without any processing.
3335 * Otherwise the list_lock will synchronize with
3336 * other processors updating the list of slabs.
3338 spin_lock_irqsave(&n
->list_lock
, flags
);
3343 } while (!cmpxchg_double_slab(s
, page
,
3350 if (likely(was_frozen
)) {
3352 * The list lock was not taken therefore no list
3353 * activity can be necessary.
3355 stat(s
, FREE_FROZEN
);
3356 } else if (new.frozen
) {
3358 * If we just froze the page then put it onto the
3359 * per cpu partial list.
3361 put_cpu_partial(s
, page
, 1);
3362 stat(s
, CPU_PARTIAL_FREE
);
3368 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
))
3372 * Objects left in the slab. If it was not on the partial list before
3375 if (!kmem_cache_has_cpu_partial(s
) && unlikely(!prior
)) {
3376 remove_full(s
, n
, page
);
3377 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
3378 stat(s
, FREE_ADD_PARTIAL
);
3380 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3386 * Slab on the partial list.
3388 remove_partial(n
, page
);
3389 stat(s
, FREE_REMOVE_PARTIAL
);
3391 /* Slab must be on the full list */
3392 remove_full(s
, n
, page
);
3395 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3397 discard_slab(s
, page
);
3401 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
3402 * can perform fastpath freeing without additional function calls.
3404 * The fastpath is only possible if we are freeing to the current cpu slab
3405 * of this processor. This typically the case if we have just allocated
3408 * If fastpath is not possible then fall back to __slab_free where we deal
3409 * with all sorts of special processing.
3411 * Bulk free of a freelist with several objects (all pointing to the
3412 * same page) possible by specifying head and tail ptr, plus objects
3413 * count (cnt). Bulk free indicated by tail pointer being set.
3415 static __always_inline
void do_slab_free(struct kmem_cache
*s
,
3416 struct page
*page
, void *head
, void *tail
,
3417 int cnt
, unsigned long addr
)
3419 void *tail_obj
= tail
? : head
;
3420 struct kmem_cache_cpu
*c
;
3423 /* memcg_slab_free_hook() is already called for bulk free. */
3425 memcg_slab_free_hook(s
, &head
, 1);
3428 * Determine the currently cpus per cpu slab.
3429 * The cpu may change afterward. However that does not matter since
3430 * data is retrieved via this pointer. If we are on the same cpu
3431 * during the cmpxchg then the free will succeed.
3433 c
= raw_cpu_ptr(s
->cpu_slab
);
3434 tid
= READ_ONCE(c
->tid
);
3436 /* Same with comment on barrier() in slab_alloc_node() */
3439 if (likely(page
== c
->page
)) {
3440 #ifndef CONFIG_PREEMPT_RT
3441 void **freelist
= READ_ONCE(c
->freelist
);
3443 set_freepointer(s
, tail_obj
, freelist
);
3445 if (unlikely(!this_cpu_cmpxchg_double(
3446 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
3448 head
, next_tid(tid
)))) {
3450 note_cmpxchg_failure("slab_free", s
, tid
);
3453 #else /* CONFIG_PREEMPT_RT */
3455 * We cannot use the lockless fastpath on PREEMPT_RT because if
3456 * a slowpath has taken the local_lock_irqsave(), it is not
3457 * protected against a fast path operation in an irq handler. So
3458 * we need to take the local_lock. We shouldn't simply defer to
3459 * __slab_free() as that wouldn't use the cpu freelist at all.
3463 local_lock(&s
->cpu_slab
->lock
);
3464 c
= this_cpu_ptr(s
->cpu_slab
);
3465 if (unlikely(page
!= c
->page
)) {
3466 local_unlock(&s
->cpu_slab
->lock
);
3470 freelist
= c
->freelist
;
3472 set_freepointer(s
, tail_obj
, freelist
);
3474 c
->tid
= next_tid(tid
);
3476 local_unlock(&s
->cpu_slab
->lock
);
3478 stat(s
, FREE_FASTPATH
);
3480 __slab_free(s
, page
, head
, tail_obj
, cnt
, addr
);
3484 static __always_inline
void slab_free(struct kmem_cache
*s
, struct page
*page
,
3485 void *head
, void *tail
, int cnt
,
3489 * With KASAN enabled slab_free_freelist_hook modifies the freelist
3490 * to remove objects, whose reuse must be delayed.
3492 if (slab_free_freelist_hook(s
, &head
, &tail
, &cnt
))
3493 do_slab_free(s
, page
, head
, tail
, cnt
, addr
);
3496 #ifdef CONFIG_KASAN_GENERIC
3497 void ___cache_free(struct kmem_cache
*cache
, void *x
, unsigned long addr
)
3499 do_slab_free(cache
, virt_to_head_page(x
), x
, NULL
, 1, addr
);
3503 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
3505 s
= cache_from_obj(s
, x
);
3508 slab_free(s
, virt_to_head_page(x
), x
, NULL
, 1, _RET_IP_
);
3509 trace_kmem_cache_free(_RET_IP_
, x
, s
->name
);
3511 EXPORT_SYMBOL(kmem_cache_free
);
3513 struct detached_freelist
{
3518 struct kmem_cache
*s
;
3521 static inline void free_nonslab_page(struct page
*page
, void *object
)
3523 unsigned int order
= compound_order(page
);
3525 VM_BUG_ON_PAGE(!PageCompound(page
), page
);
3527 mod_lruvec_page_state(page
, NR_SLAB_UNRECLAIMABLE_B
, -(PAGE_SIZE
<< order
));
3528 __free_pages(page
, order
);
3532 * This function progressively scans the array with free objects (with
3533 * a limited look ahead) and extract objects belonging to the same
3534 * page. It builds a detached freelist directly within the given
3535 * page/objects. This can happen without any need for
3536 * synchronization, because the objects are owned by running process.
3537 * The freelist is build up as a single linked list in the objects.
3538 * The idea is, that this detached freelist can then be bulk
3539 * transferred to the real freelist(s), but only requiring a single
3540 * synchronization primitive. Look ahead in the array is limited due
3541 * to performance reasons.
3544 int build_detached_freelist(struct kmem_cache
*s
, size_t size
,
3545 void **p
, struct detached_freelist
*df
)
3547 size_t first_skipped_index
= 0;
3552 /* Always re-init detached_freelist */
3557 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3558 } while (!object
&& size
);
3563 page
= virt_to_head_page(object
);
3565 /* Handle kalloc'ed objects */
3566 if (unlikely(!PageSlab(page
))) {
3567 free_nonslab_page(page
, object
);
3568 p
[size
] = NULL
; /* mark object processed */
3571 /* Derive kmem_cache from object */
3572 df
->s
= page
->slab_cache
;
3574 df
->s
= cache_from_obj(s
, object
); /* Support for memcg */
3577 if (is_kfence_address(object
)) {
3578 slab_free_hook(df
->s
, object
, false);
3579 __kfence_free(object
);
3580 p
[size
] = NULL
; /* mark object processed */
3584 /* Start new detached freelist */
3586 set_freepointer(df
->s
, object
, NULL
);
3588 df
->freelist
= object
;
3589 p
[size
] = NULL
; /* mark object processed */
3595 continue; /* Skip processed objects */
3597 /* df->page is always set at this point */
3598 if (df
->page
== virt_to_head_page(object
)) {
3599 /* Opportunity build freelist */
3600 set_freepointer(df
->s
, object
, df
->freelist
);
3601 df
->freelist
= object
;
3603 p
[size
] = NULL
; /* mark object processed */
3608 /* Limit look ahead search */
3612 if (!first_skipped_index
)
3613 first_skipped_index
= size
+ 1;
3616 return first_skipped_index
;
3619 /* Note that interrupts must be enabled when calling this function. */
3620 void kmem_cache_free_bulk(struct kmem_cache
*s
, size_t size
, void **p
)
3625 memcg_slab_free_hook(s
, p
, size
);
3627 struct detached_freelist df
;
3629 size
= build_detached_freelist(s
, size
, p
, &df
);
3633 slab_free(df
.s
, df
.page
, df
.freelist
, df
.tail
, df
.cnt
, _RET_IP_
);
3634 } while (likely(size
));
3636 EXPORT_SYMBOL(kmem_cache_free_bulk
);
3638 /* Note that interrupts must be enabled when calling this function. */
3639 int kmem_cache_alloc_bulk(struct kmem_cache
*s
, gfp_t flags
, size_t size
,
3642 struct kmem_cache_cpu
*c
;
3644 struct obj_cgroup
*objcg
= NULL
;
3646 /* memcg and kmem_cache debug support */
3647 s
= slab_pre_alloc_hook(s
, &objcg
, size
, flags
);
3651 * Drain objects in the per cpu slab, while disabling local
3652 * IRQs, which protects against PREEMPT and interrupts
3653 * handlers invoking normal fastpath.
3655 c
= slub_get_cpu_ptr(s
->cpu_slab
);
3656 local_lock_irq(&s
->cpu_slab
->lock
);
3658 for (i
= 0; i
< size
; i
++) {
3659 void *object
= kfence_alloc(s
, s
->object_size
, flags
);
3661 if (unlikely(object
)) {
3666 object
= c
->freelist
;
3667 if (unlikely(!object
)) {
3669 * We may have removed an object from c->freelist using
3670 * the fastpath in the previous iteration; in that case,
3671 * c->tid has not been bumped yet.
3672 * Since ___slab_alloc() may reenable interrupts while
3673 * allocating memory, we should bump c->tid now.
3675 c
->tid
= next_tid(c
->tid
);
3677 local_unlock_irq(&s
->cpu_slab
->lock
);
3680 * Invoking slow path likely have side-effect
3681 * of re-populating per CPU c->freelist
3683 p
[i
] = ___slab_alloc(s
, flags
, NUMA_NO_NODE
,
3685 if (unlikely(!p
[i
]))
3688 c
= this_cpu_ptr(s
->cpu_slab
);
3689 maybe_wipe_obj_freeptr(s
, p
[i
]);
3691 local_lock_irq(&s
->cpu_slab
->lock
);
3693 continue; /* goto for-loop */
3695 c
->freelist
= get_freepointer(s
, object
);
3697 maybe_wipe_obj_freeptr(s
, p
[i
]);
3699 c
->tid
= next_tid(c
->tid
);
3700 local_unlock_irq(&s
->cpu_slab
->lock
);
3701 slub_put_cpu_ptr(s
->cpu_slab
);
3704 * memcg and kmem_cache debug support and memory initialization.
3705 * Done outside of the IRQ disabled fastpath loop.
3707 slab_post_alloc_hook(s
, objcg
, flags
, size
, p
,
3708 slab_want_init_on_alloc(flags
, s
));
3711 slub_put_cpu_ptr(s
->cpu_slab
);
3712 slab_post_alloc_hook(s
, objcg
, flags
, i
, p
, false);
3713 __kmem_cache_free_bulk(s
, i
, p
);
3716 EXPORT_SYMBOL(kmem_cache_alloc_bulk
);
3720 * Object placement in a slab is made very easy because we always start at
3721 * offset 0. If we tune the size of the object to the alignment then we can
3722 * get the required alignment by putting one properly sized object after
3725 * Notice that the allocation order determines the sizes of the per cpu
3726 * caches. Each processor has always one slab available for allocations.
3727 * Increasing the allocation order reduces the number of times that slabs
3728 * must be moved on and off the partial lists and is therefore a factor in
3733 * Minimum / Maximum order of slab pages. This influences locking overhead
3734 * and slab fragmentation. A higher order reduces the number of partial slabs
3735 * and increases the number of allocations possible without having to
3736 * take the list_lock.
3738 static unsigned int slub_min_order
;
3739 static unsigned int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
3740 static unsigned int slub_min_objects
;
3743 * Calculate the order of allocation given an slab object size.
3745 * The order of allocation has significant impact on performance and other
3746 * system components. Generally order 0 allocations should be preferred since
3747 * order 0 does not cause fragmentation in the page allocator. Larger objects
3748 * be problematic to put into order 0 slabs because there may be too much
3749 * unused space left. We go to a higher order if more than 1/16th of the slab
3752 * In order to reach satisfactory performance we must ensure that a minimum
3753 * number of objects is in one slab. Otherwise we may generate too much
3754 * activity on the partial lists which requires taking the list_lock. This is
3755 * less a concern for large slabs though which are rarely used.
3757 * slub_max_order specifies the order where we begin to stop considering the
3758 * number of objects in a slab as critical. If we reach slub_max_order then
3759 * we try to keep the page order as low as possible. So we accept more waste
3760 * of space in favor of a small page order.
3762 * Higher order allocations also allow the placement of more objects in a
3763 * slab and thereby reduce object handling overhead. If the user has
3764 * requested a higher minimum order then we start with that one instead of
3765 * the smallest order which will fit the object.
3767 static inline unsigned int slab_order(unsigned int size
,
3768 unsigned int min_objects
, unsigned int max_order
,
3769 unsigned int fract_leftover
)
3771 unsigned int min_order
= slub_min_order
;
3774 if (order_objects(min_order
, size
) > MAX_OBJS_PER_PAGE
)
3775 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
3777 for (order
= max(min_order
, (unsigned int)get_order(min_objects
* size
));
3778 order
<= max_order
; order
++) {
3780 unsigned int slab_size
= (unsigned int)PAGE_SIZE
<< order
;
3783 rem
= slab_size
% size
;
3785 if (rem
<= slab_size
/ fract_leftover
)
3792 static inline int calculate_order(unsigned int size
)
3795 unsigned int min_objects
;
3796 unsigned int max_objects
;
3797 unsigned int nr_cpus
;
3800 * Attempt to find best configuration for a slab. This
3801 * works by first attempting to generate a layout with
3802 * the best configuration and backing off gradually.
3804 * First we increase the acceptable waste in a slab. Then
3805 * we reduce the minimum objects required in a slab.
3807 min_objects
= slub_min_objects
;
3810 * Some architectures will only update present cpus when
3811 * onlining them, so don't trust the number if it's just 1. But
3812 * we also don't want to use nr_cpu_ids always, as on some other
3813 * architectures, there can be many possible cpus, but never
3814 * onlined. Here we compromise between trying to avoid too high
3815 * order on systems that appear larger than they are, and too
3816 * low order on systems that appear smaller than they are.
3818 nr_cpus
= num_present_cpus();
3820 nr_cpus
= nr_cpu_ids
;
3821 min_objects
= 4 * (fls(nr_cpus
) + 1);
3823 max_objects
= order_objects(slub_max_order
, size
);
3824 min_objects
= min(min_objects
, max_objects
);
3826 while (min_objects
> 1) {
3827 unsigned int fraction
;
3830 while (fraction
>= 4) {
3831 order
= slab_order(size
, min_objects
,
3832 slub_max_order
, fraction
);
3833 if (order
<= slub_max_order
)
3841 * We were unable to place multiple objects in a slab. Now
3842 * lets see if we can place a single object there.
3844 order
= slab_order(size
, 1, slub_max_order
, 1);
3845 if (order
<= slub_max_order
)
3849 * Doh this slab cannot be placed using slub_max_order.
3851 order
= slab_order(size
, 1, MAX_ORDER
, 1);
3852 if (order
< MAX_ORDER
)
3858 init_kmem_cache_node(struct kmem_cache_node
*n
)
3861 spin_lock_init(&n
->list_lock
);
3862 INIT_LIST_HEAD(&n
->partial
);
3863 #ifdef CONFIG_SLUB_DEBUG
3864 atomic_long_set(&n
->nr_slabs
, 0);
3865 atomic_long_set(&n
->total_objects
, 0);
3866 INIT_LIST_HEAD(&n
->full
);
3870 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
3872 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
3873 KMALLOC_SHIFT_HIGH
* sizeof(struct kmem_cache_cpu
));
3876 * Must align to double word boundary for the double cmpxchg
3877 * instructions to work; see __pcpu_double_call_return_bool().
3879 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
3880 2 * sizeof(void *));
3885 init_kmem_cache_cpus(s
);
3890 static struct kmem_cache
*kmem_cache_node
;
3893 * No kmalloc_node yet so do it by hand. We know that this is the first
3894 * slab on the node for this slabcache. There are no concurrent accesses
3897 * Note that this function only works on the kmem_cache_node
3898 * when allocating for the kmem_cache_node. This is used for bootstrapping
3899 * memory on a fresh node that has no slab structures yet.
3901 static void early_kmem_cache_node_alloc(int node
)
3904 struct kmem_cache_node
*n
;
3906 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
3908 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
3911 if (page_to_nid(page
) != node
) {
3912 pr_err("SLUB: Unable to allocate memory from node %d\n", node
);
3913 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3918 #ifdef CONFIG_SLUB_DEBUG
3919 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
3920 init_tracking(kmem_cache_node
, n
);
3922 n
= kasan_slab_alloc(kmem_cache_node
, n
, GFP_KERNEL
, false);
3923 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
3926 kmem_cache_node
->node
[node
] = n
;
3927 init_kmem_cache_node(n
);
3928 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
3931 * No locks need to be taken here as it has just been
3932 * initialized and there is no concurrent access.
3934 __add_partial(n
, page
, DEACTIVATE_TO_HEAD
);
3937 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
3940 struct kmem_cache_node
*n
;
3942 for_each_kmem_cache_node(s
, node
, n
) {
3943 s
->node
[node
] = NULL
;
3944 kmem_cache_free(kmem_cache_node
, n
);
3948 void __kmem_cache_release(struct kmem_cache
*s
)
3950 cache_random_seq_destroy(s
);
3951 free_percpu(s
->cpu_slab
);
3952 free_kmem_cache_nodes(s
);
3955 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
3959 for_each_node_mask(node
, slab_nodes
) {
3960 struct kmem_cache_node
*n
;
3962 if (slab_state
== DOWN
) {
3963 early_kmem_cache_node_alloc(node
);
3966 n
= kmem_cache_alloc_node(kmem_cache_node
,
3970 free_kmem_cache_nodes(s
);
3974 init_kmem_cache_node(n
);
3980 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
3982 if (min
< MIN_PARTIAL
)
3984 else if (min
> MAX_PARTIAL
)
3986 s
->min_partial
= min
;
3989 static void set_cpu_partial(struct kmem_cache
*s
)
3991 #ifdef CONFIG_SLUB_CPU_PARTIAL
3993 * cpu_partial determined the maximum number of objects kept in the
3994 * per cpu partial lists of a processor.
3996 * Per cpu partial lists mainly contain slabs that just have one
3997 * object freed. If they are used for allocation then they can be
3998 * filled up again with minimal effort. The slab will never hit the
3999 * per node partial lists and therefore no locking will be required.
4001 * This setting also determines
4003 * A) The number of objects from per cpu partial slabs dumped to the
4004 * per node list when we reach the limit.
4005 * B) The number of objects in cpu partial slabs to extract from the
4006 * per node list when we run out of per cpu objects. We only fetch
4007 * 50% to keep some capacity around for frees.
4009 if (!kmem_cache_has_cpu_partial(s
))
4010 slub_set_cpu_partial(s
, 0);
4011 else if (s
->size
>= PAGE_SIZE
)
4012 slub_set_cpu_partial(s
, 2);
4013 else if (s
->size
>= 1024)
4014 slub_set_cpu_partial(s
, 6);
4015 else if (s
->size
>= 256)
4016 slub_set_cpu_partial(s
, 13);
4018 slub_set_cpu_partial(s
, 30);
4023 * calculate_sizes() determines the order and the distribution of data within
4026 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
4028 slab_flags_t flags
= s
->flags
;
4029 unsigned int size
= s
->object_size
;
4033 * Round up object size to the next word boundary. We can only
4034 * place the free pointer at word boundaries and this determines
4035 * the possible location of the free pointer.
4037 size
= ALIGN(size
, sizeof(void *));
4039 #ifdef CONFIG_SLUB_DEBUG
4041 * Determine if we can poison the object itself. If the user of
4042 * the slab may touch the object after free or before allocation
4043 * then we should never poison the object itself.
4045 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_TYPESAFE_BY_RCU
) &&
4047 s
->flags
|= __OBJECT_POISON
;
4049 s
->flags
&= ~__OBJECT_POISON
;
4053 * If we are Redzoning then check if there is some space between the
4054 * end of the object and the free pointer. If not then add an
4055 * additional word to have some bytes to store Redzone information.
4057 if ((flags
& SLAB_RED_ZONE
) && size
== s
->object_size
)
4058 size
+= sizeof(void *);
4062 * With that we have determined the number of bytes in actual use
4063 * by the object and redzoning.
4067 if ((flags
& (SLAB_TYPESAFE_BY_RCU
| SLAB_POISON
)) ||
4068 ((flags
& SLAB_RED_ZONE
) && s
->object_size
< sizeof(void *)) ||
4071 * Relocate free pointer after the object if it is not
4072 * permitted to overwrite the first word of the object on
4075 * This is the case if we do RCU, have a constructor or
4076 * destructor, are poisoning the objects, or are
4077 * redzoning an object smaller than sizeof(void *).
4079 * The assumption that s->offset >= s->inuse means free
4080 * pointer is outside of the object is used in the
4081 * freeptr_outside_object() function. If that is no
4082 * longer true, the function needs to be modified.
4085 size
+= sizeof(void *);
4088 * Store freelist pointer near middle of object to keep
4089 * it away from the edges of the object to avoid small
4090 * sized over/underflows from neighboring allocations.
4092 s
->offset
= ALIGN_DOWN(s
->object_size
/ 2, sizeof(void *));
4095 #ifdef CONFIG_SLUB_DEBUG
4096 if (flags
& SLAB_STORE_USER
)
4098 * Need to store information about allocs and frees after
4101 size
+= 2 * sizeof(struct track
);
4104 kasan_cache_create(s
, &size
, &s
->flags
);
4105 #ifdef CONFIG_SLUB_DEBUG
4106 if (flags
& SLAB_RED_ZONE
) {
4108 * Add some empty padding so that we can catch
4109 * overwrites from earlier objects rather than let
4110 * tracking information or the free pointer be
4111 * corrupted if a user writes before the start
4114 size
+= sizeof(void *);
4116 s
->red_left_pad
= sizeof(void *);
4117 s
->red_left_pad
= ALIGN(s
->red_left_pad
, s
->align
);
4118 size
+= s
->red_left_pad
;
4123 * SLUB stores one object immediately after another beginning from
4124 * offset 0. In order to align the objects we have to simply size
4125 * each object to conform to the alignment.
4127 size
= ALIGN(size
, s
->align
);
4129 s
->reciprocal_size
= reciprocal_value(size
);
4130 if (forced_order
>= 0)
4131 order
= forced_order
;
4133 order
= calculate_order(size
);
4140 s
->allocflags
|= __GFP_COMP
;
4142 if (s
->flags
& SLAB_CACHE_DMA
)
4143 s
->allocflags
|= GFP_DMA
;
4145 if (s
->flags
& SLAB_CACHE_DMA32
)
4146 s
->allocflags
|= GFP_DMA32
;
4148 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
4149 s
->allocflags
|= __GFP_RECLAIMABLE
;
4152 * Determine the number of objects per slab
4154 s
->oo
= oo_make(order
, size
);
4155 s
->min
= oo_make(get_order(size
), size
);
4156 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
4159 return !!oo_objects(s
->oo
);
4162 static int kmem_cache_open(struct kmem_cache
*s
, slab_flags_t flags
)
4164 s
->flags
= kmem_cache_flags(s
->size
, flags
, s
->name
);
4165 #ifdef CONFIG_SLAB_FREELIST_HARDENED
4166 s
->random
= get_random_long();
4169 if (!calculate_sizes(s
, -1))
4171 if (disable_higher_order_debug
) {
4173 * Disable debugging flags that store metadata if the min slab
4176 if (get_order(s
->size
) > get_order(s
->object_size
)) {
4177 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
4179 if (!calculate_sizes(s
, -1))
4184 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
4185 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
4186 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_NO_CMPXCHG
) == 0)
4187 /* Enable fast mode */
4188 s
->flags
|= __CMPXCHG_DOUBLE
;
4192 * The larger the object size is, the more pages we want on the partial
4193 * list to avoid pounding the page allocator excessively.
4195 set_min_partial(s
, ilog2(s
->size
) / 2);
4200 s
->remote_node_defrag_ratio
= 1000;
4203 /* Initialize the pre-computed randomized freelist if slab is up */
4204 if (slab_state
>= UP
) {
4205 if (init_cache_random_seq(s
))
4209 if (!init_kmem_cache_nodes(s
))
4212 if (alloc_kmem_cache_cpus(s
))
4216 __kmem_cache_release(s
);
4220 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
4223 #ifdef CONFIG_SLUB_DEBUG
4224 void *addr
= page_address(page
);
4225 unsigned long flags
;
4229 slab_err(s
, page
, text
, s
->name
);
4230 slab_lock(page
, &flags
);
4232 map
= get_map(s
, page
);
4233 for_each_object(p
, s
, addr
, page
->objects
) {
4235 if (!test_bit(__obj_to_index(s
, addr
, p
), map
)) {
4236 pr_err("Object 0x%p @offset=%tu\n", p
, p
- addr
);
4237 print_tracking(s
, p
);
4241 slab_unlock(page
, &flags
);
4246 * Attempt to free all partial slabs on a node.
4247 * This is called from __kmem_cache_shutdown(). We must take list_lock
4248 * because sysfs file might still access partial list after the shutdowning.
4250 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
4253 struct page
*page
, *h
;
4255 BUG_ON(irqs_disabled());
4256 spin_lock_irq(&n
->list_lock
);
4257 list_for_each_entry_safe(page
, h
, &n
->partial
, slab_list
) {
4259 remove_partial(n
, page
);
4260 list_add(&page
->slab_list
, &discard
);
4262 list_slab_objects(s
, page
,
4263 "Objects remaining in %s on __kmem_cache_shutdown()");
4266 spin_unlock_irq(&n
->list_lock
);
4268 list_for_each_entry_safe(page
, h
, &discard
, slab_list
)
4269 discard_slab(s
, page
);
4272 bool __kmem_cache_empty(struct kmem_cache
*s
)
4275 struct kmem_cache_node
*n
;
4277 for_each_kmem_cache_node(s
, node
, n
)
4278 if (n
->nr_partial
|| slabs_node(s
, node
))
4284 * Release all resources used by a slab cache.
4286 int __kmem_cache_shutdown(struct kmem_cache
*s
)
4289 struct kmem_cache_node
*n
;
4291 flush_all_cpus_locked(s
);
4292 /* Attempt to free all objects */
4293 for_each_kmem_cache_node(s
, node
, n
) {
4295 if (n
->nr_partial
|| slabs_node(s
, node
))
4301 #ifdef CONFIG_PRINTK
4302 void kmem_obj_info(struct kmem_obj_info
*kpp
, void *object
, struct page
*page
)
4305 int __maybe_unused i
;
4309 struct kmem_cache
*s
= page
->slab_cache
;
4310 struct track __maybe_unused
*trackp
;
4312 kpp
->kp_ptr
= object
;
4313 kpp
->kp_page
= page
;
4314 kpp
->kp_slab_cache
= s
;
4315 base
= page_address(page
);
4316 objp0
= kasan_reset_tag(object
);
4317 #ifdef CONFIG_SLUB_DEBUG
4318 objp
= restore_red_left(s
, objp0
);
4322 objnr
= obj_to_index(s
, page
, objp
);
4323 kpp
->kp_data_offset
= (unsigned long)((char *)objp0
- (char *)objp
);
4324 objp
= base
+ s
->size
* objnr
;
4325 kpp
->kp_objp
= objp
;
4326 if (WARN_ON_ONCE(objp
< base
|| objp
>= base
+ page
->objects
* s
->size
|| (objp
- base
) % s
->size
) ||
4327 !(s
->flags
& SLAB_STORE_USER
))
4329 #ifdef CONFIG_SLUB_DEBUG
4330 objp
= fixup_red_left(s
, objp
);
4331 trackp
= get_track(s
, objp
, TRACK_ALLOC
);
4332 kpp
->kp_ret
= (void *)trackp
->addr
;
4333 #ifdef CONFIG_STACKTRACE
4334 for (i
= 0; i
< KS_ADDRS_COUNT
&& i
< TRACK_ADDRS_COUNT
; i
++) {
4335 kpp
->kp_stack
[i
] = (void *)trackp
->addrs
[i
];
4336 if (!kpp
->kp_stack
[i
])
4340 trackp
= get_track(s
, objp
, TRACK_FREE
);
4341 for (i
= 0; i
< KS_ADDRS_COUNT
&& i
< TRACK_ADDRS_COUNT
; i
++) {
4342 kpp
->kp_free_stack
[i
] = (void *)trackp
->addrs
[i
];
4343 if (!kpp
->kp_free_stack
[i
])
4351 /********************************************************************
4353 *******************************************************************/
4355 static int __init
setup_slub_min_order(char *str
)
4357 get_option(&str
, (int *)&slub_min_order
);
4362 __setup("slub_min_order=", setup_slub_min_order
);
4364 static int __init
setup_slub_max_order(char *str
)
4366 get_option(&str
, (int *)&slub_max_order
);
4367 slub_max_order
= min(slub_max_order
, (unsigned int)MAX_ORDER
- 1);
4372 __setup("slub_max_order=", setup_slub_max_order
);
4374 static int __init
setup_slub_min_objects(char *str
)
4376 get_option(&str
, (int *)&slub_min_objects
);
4381 __setup("slub_min_objects=", setup_slub_min_objects
);
4383 void *__kmalloc(size_t size
, gfp_t flags
)
4385 struct kmem_cache
*s
;
4388 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
4389 return kmalloc_large(size
, flags
);
4391 s
= kmalloc_slab(size
, flags
);
4393 if (unlikely(ZERO_OR_NULL_PTR(s
)))
4396 ret
= slab_alloc(s
, flags
, _RET_IP_
, size
);
4398 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
4400 ret
= kasan_kmalloc(s
, ret
, size
, flags
);
4404 EXPORT_SYMBOL(__kmalloc
);
4407 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
4411 unsigned int order
= get_order(size
);
4413 flags
|= __GFP_COMP
;
4414 page
= alloc_pages_node(node
, flags
, order
);
4416 ptr
= page_address(page
);
4417 mod_lruvec_page_state(page
, NR_SLAB_UNRECLAIMABLE_B
,
4418 PAGE_SIZE
<< order
);
4421 return kmalloc_large_node_hook(ptr
, size
, flags
);
4424 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
4426 struct kmem_cache
*s
;
4429 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
4430 ret
= kmalloc_large_node(size
, flags
, node
);
4432 trace_kmalloc_node(_RET_IP_
, ret
,
4433 size
, PAGE_SIZE
<< get_order(size
),
4439 s
= kmalloc_slab(size
, flags
);
4441 if (unlikely(ZERO_OR_NULL_PTR(s
)))
4444 ret
= slab_alloc_node(s
, flags
, node
, _RET_IP_
, size
);
4446 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
4448 ret
= kasan_kmalloc(s
, ret
, size
, flags
);
4452 EXPORT_SYMBOL(__kmalloc_node
);
4453 #endif /* CONFIG_NUMA */
4455 #ifdef CONFIG_HARDENED_USERCOPY
4457 * Rejects incorrectly sized objects and objects that are to be copied
4458 * to/from userspace but do not fall entirely within the containing slab
4459 * cache's usercopy region.
4461 * Returns NULL if check passes, otherwise const char * to name of cache
4462 * to indicate an error.
4464 void __check_heap_object(const void *ptr
, unsigned long n
, struct page
*page
,
4467 struct kmem_cache
*s
;
4468 unsigned int offset
;
4470 bool is_kfence
= is_kfence_address(ptr
);
4472 ptr
= kasan_reset_tag(ptr
);
4474 /* Find object and usable object size. */
4475 s
= page
->slab_cache
;
4477 /* Reject impossible pointers. */
4478 if (ptr
< page_address(page
))
4479 usercopy_abort("SLUB object not in SLUB page?!", NULL
,
4482 /* Find offset within object. */
4484 offset
= ptr
- kfence_object_start(ptr
);
4486 offset
= (ptr
- page_address(page
)) % s
->size
;
4488 /* Adjust for redzone and reject if within the redzone. */
4489 if (!is_kfence
&& kmem_cache_debug_flags(s
, SLAB_RED_ZONE
)) {
4490 if (offset
< s
->red_left_pad
)
4491 usercopy_abort("SLUB object in left red zone",
4492 s
->name
, to_user
, offset
, n
);
4493 offset
-= s
->red_left_pad
;
4496 /* Allow address range falling entirely within usercopy region. */
4497 if (offset
>= s
->useroffset
&&
4498 offset
- s
->useroffset
<= s
->usersize
&&
4499 n
<= s
->useroffset
- offset
+ s
->usersize
)
4503 * If the copy is still within the allocated object, produce
4504 * a warning instead of rejecting the copy. This is intended
4505 * to be a temporary method to find any missing usercopy
4508 object_size
= slab_ksize(s
);
4509 if (usercopy_fallback
&&
4510 offset
<= object_size
&& n
<= object_size
- offset
) {
4511 usercopy_warn("SLUB object", s
->name
, to_user
, offset
, n
);
4515 usercopy_abort("SLUB object", s
->name
, to_user
, offset
, n
);
4517 #endif /* CONFIG_HARDENED_USERCOPY */
4519 size_t __ksize(const void *object
)
4523 if (unlikely(object
== ZERO_SIZE_PTR
))
4526 page
= virt_to_head_page(object
);
4528 if (unlikely(!PageSlab(page
))) {
4529 WARN_ON(!PageCompound(page
));
4530 return page_size(page
);
4533 return slab_ksize(page
->slab_cache
);
4535 EXPORT_SYMBOL(__ksize
);
4537 void kfree(const void *x
)
4540 void *object
= (void *)x
;
4542 trace_kfree(_RET_IP_
, x
);
4544 if (unlikely(ZERO_OR_NULL_PTR(x
)))
4547 page
= virt_to_head_page(x
);
4548 if (unlikely(!PageSlab(page
))) {
4549 free_nonslab_page(page
, object
);
4552 slab_free(page
->slab_cache
, page
, object
, NULL
, 1, _RET_IP_
);
4554 EXPORT_SYMBOL(kfree
);
4556 #define SHRINK_PROMOTE_MAX 32
4559 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
4560 * up most to the head of the partial lists. New allocations will then
4561 * fill those up and thus they can be removed from the partial lists.
4563 * The slabs with the least items are placed last. This results in them
4564 * being allocated from last increasing the chance that the last objects
4565 * are freed in them.
4567 static int __kmem_cache_do_shrink(struct kmem_cache
*s
)
4571 struct kmem_cache_node
*n
;
4574 struct list_head discard
;
4575 struct list_head promote
[SHRINK_PROMOTE_MAX
];
4576 unsigned long flags
;
4579 for_each_kmem_cache_node(s
, node
, n
) {
4580 INIT_LIST_HEAD(&discard
);
4581 for (i
= 0; i
< SHRINK_PROMOTE_MAX
; i
++)
4582 INIT_LIST_HEAD(promote
+ i
);
4584 spin_lock_irqsave(&n
->list_lock
, flags
);
4587 * Build lists of slabs to discard or promote.
4589 * Note that concurrent frees may occur while we hold the
4590 * list_lock. page->inuse here is the upper limit.
4592 list_for_each_entry_safe(page
, t
, &n
->partial
, slab_list
) {
4593 int free
= page
->objects
- page
->inuse
;
4595 /* Do not reread page->inuse */
4598 /* We do not keep full slabs on the list */
4601 if (free
== page
->objects
) {
4602 list_move(&page
->slab_list
, &discard
);
4604 } else if (free
<= SHRINK_PROMOTE_MAX
)
4605 list_move(&page
->slab_list
, promote
+ free
- 1);
4609 * Promote the slabs filled up most to the head of the
4612 for (i
= SHRINK_PROMOTE_MAX
- 1; i
>= 0; i
--)
4613 list_splice(promote
+ i
, &n
->partial
);
4615 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4617 /* Release empty slabs */
4618 list_for_each_entry_safe(page
, t
, &discard
, slab_list
)
4619 discard_slab(s
, page
);
4621 if (slabs_node(s
, node
))
4628 int __kmem_cache_shrink(struct kmem_cache
*s
)
4631 return __kmem_cache_do_shrink(s
);
4634 static int slab_mem_going_offline_callback(void *arg
)
4636 struct kmem_cache
*s
;
4638 mutex_lock(&slab_mutex
);
4639 list_for_each_entry(s
, &slab_caches
, list
) {
4640 flush_all_cpus_locked(s
);
4641 __kmem_cache_do_shrink(s
);
4643 mutex_unlock(&slab_mutex
);
4648 static void slab_mem_offline_callback(void *arg
)
4650 struct memory_notify
*marg
= arg
;
4653 offline_node
= marg
->status_change_nid_normal
;
4656 * If the node still has available memory. we need kmem_cache_node
4659 if (offline_node
< 0)
4662 mutex_lock(&slab_mutex
);
4663 node_clear(offline_node
, slab_nodes
);
4665 * We no longer free kmem_cache_node structures here, as it would be
4666 * racy with all get_node() users, and infeasible to protect them with
4669 mutex_unlock(&slab_mutex
);
4672 static int slab_mem_going_online_callback(void *arg
)
4674 struct kmem_cache_node
*n
;
4675 struct kmem_cache
*s
;
4676 struct memory_notify
*marg
= arg
;
4677 int nid
= marg
->status_change_nid_normal
;
4681 * If the node's memory is already available, then kmem_cache_node is
4682 * already created. Nothing to do.
4688 * We are bringing a node online. No memory is available yet. We must
4689 * allocate a kmem_cache_node structure in order to bring the node
4692 mutex_lock(&slab_mutex
);
4693 list_for_each_entry(s
, &slab_caches
, list
) {
4695 * The structure may already exist if the node was previously
4696 * onlined and offlined.
4698 if (get_node(s
, nid
))
4701 * XXX: kmem_cache_alloc_node will fallback to other nodes
4702 * since memory is not yet available from the node that
4705 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
4710 init_kmem_cache_node(n
);
4714 * Any cache created after this point will also have kmem_cache_node
4715 * initialized for the new node.
4717 node_set(nid
, slab_nodes
);
4719 mutex_unlock(&slab_mutex
);
4723 static int slab_memory_callback(struct notifier_block
*self
,
4724 unsigned long action
, void *arg
)
4729 case MEM_GOING_ONLINE
:
4730 ret
= slab_mem_going_online_callback(arg
);
4732 case MEM_GOING_OFFLINE
:
4733 ret
= slab_mem_going_offline_callback(arg
);
4736 case MEM_CANCEL_ONLINE
:
4737 slab_mem_offline_callback(arg
);
4740 case MEM_CANCEL_OFFLINE
:
4744 ret
= notifier_from_errno(ret
);
4750 static struct notifier_block slab_memory_callback_nb
= {
4751 .notifier_call
= slab_memory_callback
,
4752 .priority
= SLAB_CALLBACK_PRI
,
4755 /********************************************************************
4756 * Basic setup of slabs
4757 *******************************************************************/
4760 * Used for early kmem_cache structures that were allocated using
4761 * the page allocator. Allocate them properly then fix up the pointers
4762 * that may be pointing to the wrong kmem_cache structure.
4765 static struct kmem_cache
* __init
bootstrap(struct kmem_cache
*static_cache
)
4768 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
4769 struct kmem_cache_node
*n
;
4771 memcpy(s
, static_cache
, kmem_cache
->object_size
);
4774 * This runs very early, and only the boot processor is supposed to be
4775 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4778 __flush_cpu_slab(s
, smp_processor_id());
4779 for_each_kmem_cache_node(s
, node
, n
) {
4782 list_for_each_entry(p
, &n
->partial
, slab_list
)
4785 #ifdef CONFIG_SLUB_DEBUG
4786 list_for_each_entry(p
, &n
->full
, slab_list
)
4790 list_add(&s
->list
, &slab_caches
);
4794 void __init
kmem_cache_init(void)
4796 static __initdata
struct kmem_cache boot_kmem_cache
,
4797 boot_kmem_cache_node
;
4800 if (debug_guardpage_minorder())
4803 /* Print slub debugging pointers without hashing */
4804 if (__slub_debug_enabled())
4805 no_hash_pointers_enable(NULL
);
4807 kmem_cache_node
= &boot_kmem_cache_node
;
4808 kmem_cache
= &boot_kmem_cache
;
4811 * Initialize the nodemask for which we will allocate per node
4812 * structures. Here we don't need taking slab_mutex yet.
4814 for_each_node_state(node
, N_NORMAL_MEMORY
)
4815 node_set(node
, slab_nodes
);
4817 create_boot_cache(kmem_cache_node
, "kmem_cache_node",
4818 sizeof(struct kmem_cache_node
), SLAB_HWCACHE_ALIGN
, 0, 0);
4820 register_hotmemory_notifier(&slab_memory_callback_nb
);
4822 /* Able to allocate the per node structures */
4823 slab_state
= PARTIAL
;
4825 create_boot_cache(kmem_cache
, "kmem_cache",
4826 offsetof(struct kmem_cache
, node
) +
4827 nr_node_ids
* sizeof(struct kmem_cache_node
*),
4828 SLAB_HWCACHE_ALIGN
, 0, 0);
4830 kmem_cache
= bootstrap(&boot_kmem_cache
);
4831 kmem_cache_node
= bootstrap(&boot_kmem_cache_node
);
4833 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4834 setup_kmalloc_cache_index_table();
4835 create_kmalloc_caches(0);
4837 /* Setup random freelists for each cache */
4838 init_freelist_randomization();
4840 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD
, "slub:dead", NULL
,
4843 pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
4845 slub_min_order
, slub_max_order
, slub_min_objects
,
4846 nr_cpu_ids
, nr_node_ids
);
4849 void __init
kmem_cache_init_late(void)
4854 __kmem_cache_alias(const char *name
, unsigned int size
, unsigned int align
,
4855 slab_flags_t flags
, void (*ctor
)(void *))
4857 struct kmem_cache
*s
;
4859 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
4864 * Adjust the object sizes so that we clear
4865 * the complete object on kzalloc.
4867 s
->object_size
= max(s
->object_size
, size
);
4868 s
->inuse
= max(s
->inuse
, ALIGN(size
, sizeof(void *)));
4870 if (sysfs_slab_alias(s
, name
)) {
4879 int __kmem_cache_create(struct kmem_cache
*s
, slab_flags_t flags
)
4883 err
= kmem_cache_open(s
, flags
);
4887 /* Mutex is not taken during early boot */
4888 if (slab_state
<= UP
)
4891 err
= sysfs_slab_add(s
);
4893 __kmem_cache_release(s
);
4897 if (s
->flags
& SLAB_STORE_USER
)
4898 debugfs_slab_add(s
);
4903 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
4905 struct kmem_cache
*s
;
4908 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
4909 return kmalloc_large(size
, gfpflags
);
4911 s
= kmalloc_slab(size
, gfpflags
);
4913 if (unlikely(ZERO_OR_NULL_PTR(s
)))
4916 ret
= slab_alloc(s
, gfpflags
, caller
, size
);
4918 /* Honor the call site pointer we received. */
4919 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
4923 EXPORT_SYMBOL(__kmalloc_track_caller
);
4926 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
4927 int node
, unsigned long caller
)
4929 struct kmem_cache
*s
;
4932 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
4933 ret
= kmalloc_large_node(size
, gfpflags
, node
);
4935 trace_kmalloc_node(caller
, ret
,
4936 size
, PAGE_SIZE
<< get_order(size
),
4942 s
= kmalloc_slab(size
, gfpflags
);
4944 if (unlikely(ZERO_OR_NULL_PTR(s
)))
4947 ret
= slab_alloc_node(s
, gfpflags
, node
, caller
, size
);
4949 /* Honor the call site pointer we received. */
4950 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
4954 EXPORT_SYMBOL(__kmalloc_node_track_caller
);
4958 static int count_inuse(struct page
*page
)
4963 static int count_total(struct page
*page
)
4965 return page
->objects
;
4969 #ifdef CONFIG_SLUB_DEBUG
4970 static void validate_slab(struct kmem_cache
*s
, struct page
*page
,
4971 unsigned long *obj_map
)
4974 void *addr
= page_address(page
);
4975 unsigned long flags
;
4977 slab_lock(page
, &flags
);
4979 if (!check_slab(s
, page
) || !on_freelist(s
, page
, NULL
))
4982 /* Now we know that a valid freelist exists */
4983 __fill_map(obj_map
, s
, page
);
4984 for_each_object(p
, s
, addr
, page
->objects
) {
4985 u8 val
= test_bit(__obj_to_index(s
, addr
, p
), obj_map
) ?
4986 SLUB_RED_INACTIVE
: SLUB_RED_ACTIVE
;
4988 if (!check_object(s
, page
, p
, val
))
4992 slab_unlock(page
, &flags
);
4995 static int validate_slab_node(struct kmem_cache
*s
,
4996 struct kmem_cache_node
*n
, unsigned long *obj_map
)
4998 unsigned long count
= 0;
5000 unsigned long flags
;
5002 spin_lock_irqsave(&n
->list_lock
, flags
);
5004 list_for_each_entry(page
, &n
->partial
, slab_list
) {
5005 validate_slab(s
, page
, obj_map
);
5008 if (count
!= n
->nr_partial
) {
5009 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
5010 s
->name
, count
, n
->nr_partial
);
5011 slab_add_kunit_errors();
5014 if (!(s
->flags
& SLAB_STORE_USER
))
5017 list_for_each_entry(page
, &n
->full
, slab_list
) {
5018 validate_slab(s
, page
, obj_map
);
5021 if (count
!= atomic_long_read(&n
->nr_slabs
)) {
5022 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
5023 s
->name
, count
, atomic_long_read(&n
->nr_slabs
));
5024 slab_add_kunit_errors();
5028 spin_unlock_irqrestore(&n
->list_lock
, flags
);
5032 long validate_slab_cache(struct kmem_cache
*s
)
5035 unsigned long count
= 0;
5036 struct kmem_cache_node
*n
;
5037 unsigned long *obj_map
;
5039 obj_map
= bitmap_alloc(oo_objects(s
->oo
), GFP_KERNEL
);
5044 for_each_kmem_cache_node(s
, node
, n
)
5045 count
+= validate_slab_node(s
, n
, obj_map
);
5047 bitmap_free(obj_map
);
5051 EXPORT_SYMBOL(validate_slab_cache
);
5053 #ifdef CONFIG_DEBUG_FS
5055 * Generate lists of code addresses where slabcache objects are allocated
5060 unsigned long count
;
5067 DECLARE_BITMAP(cpus
, NR_CPUS
);
5073 unsigned long count
;
5074 struct location
*loc
;
5077 static struct dentry
*slab_debugfs_root
;
5079 static void free_loc_track(struct loc_track
*t
)
5082 free_pages((unsigned long)t
->loc
,
5083 get_order(sizeof(struct location
) * t
->max
));
5086 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
5091 order
= get_order(sizeof(struct location
) * max
);
5093 l
= (void *)__get_free_pages(flags
, order
);
5098 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
5106 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
5107 const struct track
*track
)
5109 long start
, end
, pos
;
5111 unsigned long caddr
;
5112 unsigned long age
= jiffies
- track
->when
;
5118 pos
= start
+ (end
- start
+ 1) / 2;
5121 * There is nothing at "end". If we end up there
5122 * we need to add something to before end.
5127 caddr
= t
->loc
[pos
].addr
;
5128 if (track
->addr
== caddr
) {
5134 if (age
< l
->min_time
)
5136 if (age
> l
->max_time
)
5139 if (track
->pid
< l
->min_pid
)
5140 l
->min_pid
= track
->pid
;
5141 if (track
->pid
> l
->max_pid
)
5142 l
->max_pid
= track
->pid
;
5144 cpumask_set_cpu(track
->cpu
,
5145 to_cpumask(l
->cpus
));
5147 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
5151 if (track
->addr
< caddr
)
5158 * Not found. Insert new tracking element.
5160 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
5166 (t
->count
- pos
) * sizeof(struct location
));
5169 l
->addr
= track
->addr
;
5173 l
->min_pid
= track
->pid
;
5174 l
->max_pid
= track
->pid
;
5175 cpumask_clear(to_cpumask(l
->cpus
));
5176 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
5177 nodes_clear(l
->nodes
);
5178 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
5182 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
5183 struct page
*page
, enum track_item alloc
,
5184 unsigned long *obj_map
)
5186 void *addr
= page_address(page
);
5189 __fill_map(obj_map
, s
, page
);
5191 for_each_object(p
, s
, addr
, page
->objects
)
5192 if (!test_bit(__obj_to_index(s
, addr
, p
), obj_map
))
5193 add_location(t
, s
, get_track(s
, p
, alloc
));
5195 #endif /* CONFIG_DEBUG_FS */
5196 #endif /* CONFIG_SLUB_DEBUG */
5199 enum slab_stat_type
{
5200 SL_ALL
, /* All slabs */
5201 SL_PARTIAL
, /* Only partially allocated slabs */
5202 SL_CPU
, /* Only slabs used for cpu caches */
5203 SL_OBJECTS
, /* Determine allocated objects not slabs */
5204 SL_TOTAL
/* Determine object capacity not slabs */
5207 #define SO_ALL (1 << SL_ALL)
5208 #define SO_PARTIAL (1 << SL_PARTIAL)
5209 #define SO_CPU (1 << SL_CPU)
5210 #define SO_OBJECTS (1 << SL_OBJECTS)
5211 #define SO_TOTAL (1 << SL_TOTAL)
5213 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
5214 char *buf
, unsigned long flags
)
5216 unsigned long total
= 0;
5219 unsigned long *nodes
;
5222 nodes
= kcalloc(nr_node_ids
, sizeof(unsigned long), GFP_KERNEL
);
5226 if (flags
& SO_CPU
) {
5229 for_each_possible_cpu(cpu
) {
5230 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
,
5235 page
= READ_ONCE(c
->page
);
5239 node
= page_to_nid(page
);
5240 if (flags
& SO_TOTAL
)
5242 else if (flags
& SO_OBJECTS
)
5250 page
= slub_percpu_partial_read_once(c
);
5252 node
= page_to_nid(page
);
5253 if (flags
& SO_TOTAL
)
5255 else if (flags
& SO_OBJECTS
)
5266 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
5267 * already held which will conflict with an existing lock order:
5269 * mem_hotplug_lock->slab_mutex->kernfs_mutex
5271 * We don't really need mem_hotplug_lock (to hold off
5272 * slab_mem_going_offline_callback) here because slab's memory hot
5273 * unplug code doesn't destroy the kmem_cache->node[] data.
5276 #ifdef CONFIG_SLUB_DEBUG
5277 if (flags
& SO_ALL
) {
5278 struct kmem_cache_node
*n
;
5280 for_each_kmem_cache_node(s
, node
, n
) {
5282 if (flags
& SO_TOTAL
)
5283 x
= atomic_long_read(&n
->total_objects
);
5284 else if (flags
& SO_OBJECTS
)
5285 x
= atomic_long_read(&n
->total_objects
) -
5286 count_partial(n
, count_free
);
5288 x
= atomic_long_read(&n
->nr_slabs
);
5295 if (flags
& SO_PARTIAL
) {
5296 struct kmem_cache_node
*n
;
5298 for_each_kmem_cache_node(s
, node
, n
) {
5299 if (flags
& SO_TOTAL
)
5300 x
= count_partial(n
, count_total
);
5301 else if (flags
& SO_OBJECTS
)
5302 x
= count_partial(n
, count_inuse
);
5310 len
+= sysfs_emit_at(buf
, len
, "%lu", total
);
5312 for (node
= 0; node
< nr_node_ids
; node
++) {
5314 len
+= sysfs_emit_at(buf
, len
, " N%d=%lu",
5318 len
+= sysfs_emit_at(buf
, len
, "\n");
5324 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
5325 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
5327 struct slab_attribute
{
5328 struct attribute attr
;
5329 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
5330 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
5333 #define SLAB_ATTR_RO(_name) \
5334 static struct slab_attribute _name##_attr = \
5335 __ATTR(_name, 0400, _name##_show, NULL)
5337 #define SLAB_ATTR(_name) \
5338 static struct slab_attribute _name##_attr = \
5339 __ATTR(_name, 0600, _name##_show, _name##_store)
5341 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
5343 return sysfs_emit(buf
, "%u\n", s
->size
);
5345 SLAB_ATTR_RO(slab_size
);
5347 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
5349 return sysfs_emit(buf
, "%u\n", s
->align
);
5351 SLAB_ATTR_RO(align
);
5353 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
5355 return sysfs_emit(buf
, "%u\n", s
->object_size
);
5357 SLAB_ATTR_RO(object_size
);
5359 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
5361 return sysfs_emit(buf
, "%u\n", oo_objects(s
->oo
));
5363 SLAB_ATTR_RO(objs_per_slab
);
5365 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
5367 return sysfs_emit(buf
, "%u\n", oo_order(s
->oo
));
5369 SLAB_ATTR_RO(order
);
5371 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
5373 return sysfs_emit(buf
, "%lu\n", s
->min_partial
);
5376 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
5382 err
= kstrtoul(buf
, 10, &min
);
5386 set_min_partial(s
, min
);
5389 SLAB_ATTR(min_partial
);
5391 static ssize_t
cpu_partial_show(struct kmem_cache
*s
, char *buf
)
5393 return sysfs_emit(buf
, "%u\n", slub_cpu_partial(s
));
5396 static ssize_t
cpu_partial_store(struct kmem_cache
*s
, const char *buf
,
5399 unsigned int objects
;
5402 err
= kstrtouint(buf
, 10, &objects
);
5405 if (objects
&& !kmem_cache_has_cpu_partial(s
))
5408 slub_set_cpu_partial(s
, objects
);
5412 SLAB_ATTR(cpu_partial
);
5414 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
5418 return sysfs_emit(buf
, "%pS\n", s
->ctor
);
5422 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
5424 return sysfs_emit(buf
, "%d\n", s
->refcount
< 0 ? 0 : s
->refcount
- 1);
5426 SLAB_ATTR_RO(aliases
);
5428 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
5430 return show_slab_objects(s
, buf
, SO_PARTIAL
);
5432 SLAB_ATTR_RO(partial
);
5434 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
5436 return show_slab_objects(s
, buf
, SO_CPU
);
5438 SLAB_ATTR_RO(cpu_slabs
);
5440 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
5442 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
5444 SLAB_ATTR_RO(objects
);
5446 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
5448 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
5450 SLAB_ATTR_RO(objects_partial
);
5452 static ssize_t
slabs_cpu_partial_show(struct kmem_cache
*s
, char *buf
)
5459 for_each_online_cpu(cpu
) {
5462 page
= slub_percpu_partial(per_cpu_ptr(s
->cpu_slab
, cpu
));
5465 pages
+= page
->pages
;
5466 objects
+= page
->pobjects
;
5470 len
+= sysfs_emit_at(buf
, len
, "%d(%d)", objects
, pages
);
5473 for_each_online_cpu(cpu
) {
5476 page
= slub_percpu_partial(per_cpu_ptr(s
->cpu_slab
, cpu
));
5478 len
+= sysfs_emit_at(buf
, len
, " C%d=%d(%d)",
5479 cpu
, page
->pobjects
, page
->pages
);
5482 len
+= sysfs_emit_at(buf
, len
, "\n");
5486 SLAB_ATTR_RO(slabs_cpu_partial
);
5488 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
5490 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
5492 SLAB_ATTR_RO(reclaim_account
);
5494 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
5496 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
5498 SLAB_ATTR_RO(hwcache_align
);
5500 #ifdef CONFIG_ZONE_DMA
5501 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
5503 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
5505 SLAB_ATTR_RO(cache_dma
);
5508 static ssize_t
usersize_show(struct kmem_cache
*s
, char *buf
)
5510 return sysfs_emit(buf
, "%u\n", s
->usersize
);
5512 SLAB_ATTR_RO(usersize
);
5514 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
5516 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_TYPESAFE_BY_RCU
));
5518 SLAB_ATTR_RO(destroy_by_rcu
);
5520 #ifdef CONFIG_SLUB_DEBUG
5521 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
5523 return show_slab_objects(s
, buf
, SO_ALL
);
5525 SLAB_ATTR_RO(slabs
);
5527 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
5529 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
5531 SLAB_ATTR_RO(total_objects
);
5533 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
5535 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_CONSISTENCY_CHECKS
));
5537 SLAB_ATTR_RO(sanity_checks
);
5539 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
5541 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
5543 SLAB_ATTR_RO(trace
);
5545 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
5547 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
5550 SLAB_ATTR_RO(red_zone
);
5552 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
5554 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
5557 SLAB_ATTR_RO(poison
);
5559 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
5561 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
5564 SLAB_ATTR_RO(store_user
);
5566 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
5571 static ssize_t
validate_store(struct kmem_cache
*s
,
5572 const char *buf
, size_t length
)
5576 if (buf
[0] == '1') {
5577 ret
= validate_slab_cache(s
);
5583 SLAB_ATTR(validate
);
5585 #endif /* CONFIG_SLUB_DEBUG */
5587 #ifdef CONFIG_FAILSLAB
5588 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
5590 return sysfs_emit(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
5592 SLAB_ATTR_RO(failslab
);
5595 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
5600 static ssize_t
shrink_store(struct kmem_cache
*s
,
5601 const char *buf
, size_t length
)
5604 kmem_cache_shrink(s
);
5612 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
5614 return sysfs_emit(buf
, "%u\n", s
->remote_node_defrag_ratio
/ 10);
5617 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
5618 const char *buf
, size_t length
)
5623 err
= kstrtouint(buf
, 10, &ratio
);
5629 s
->remote_node_defrag_ratio
= ratio
* 10;
5633 SLAB_ATTR(remote_node_defrag_ratio
);
5636 #ifdef CONFIG_SLUB_STATS
5637 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
5639 unsigned long sum
= 0;
5642 int *data
= kmalloc_array(nr_cpu_ids
, sizeof(int), GFP_KERNEL
);
5647 for_each_online_cpu(cpu
) {
5648 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
5654 len
+= sysfs_emit_at(buf
, len
, "%lu", sum
);
5657 for_each_online_cpu(cpu
) {
5659 len
+= sysfs_emit_at(buf
, len
, " C%d=%u",
5664 len
+= sysfs_emit_at(buf
, len
, "\n");
5669 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
5673 for_each_online_cpu(cpu
)
5674 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
5677 #define STAT_ATTR(si, text) \
5678 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5680 return show_stat(s, buf, si); \
5682 static ssize_t text##_store(struct kmem_cache *s, \
5683 const char *buf, size_t length) \
5685 if (buf[0] != '0') \
5687 clear_stat(s, si); \
5692 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5693 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
5694 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
5695 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
5696 STAT_ATTR(FREE_FROZEN
, free_frozen
);
5697 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
5698 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
5699 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
5700 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
5701 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
5702 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
5703 STAT_ATTR(FREE_SLAB
, free_slab
);
5704 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
5705 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
5706 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
5707 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
5708 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
5709 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
5710 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
5711 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
5712 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
5713 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
5714 STAT_ATTR(CPU_PARTIAL_ALLOC
, cpu_partial_alloc
);
5715 STAT_ATTR(CPU_PARTIAL_FREE
, cpu_partial_free
);
5716 STAT_ATTR(CPU_PARTIAL_NODE
, cpu_partial_node
);
5717 STAT_ATTR(CPU_PARTIAL_DRAIN
, cpu_partial_drain
);
5718 #endif /* CONFIG_SLUB_STATS */
5720 static struct attribute
*slab_attrs
[] = {
5721 &slab_size_attr
.attr
,
5722 &object_size_attr
.attr
,
5723 &objs_per_slab_attr
.attr
,
5725 &min_partial_attr
.attr
,
5726 &cpu_partial_attr
.attr
,
5728 &objects_partial_attr
.attr
,
5730 &cpu_slabs_attr
.attr
,
5734 &hwcache_align_attr
.attr
,
5735 &reclaim_account_attr
.attr
,
5736 &destroy_by_rcu_attr
.attr
,
5738 &slabs_cpu_partial_attr
.attr
,
5739 #ifdef CONFIG_SLUB_DEBUG
5740 &total_objects_attr
.attr
,
5742 &sanity_checks_attr
.attr
,
5744 &red_zone_attr
.attr
,
5746 &store_user_attr
.attr
,
5747 &validate_attr
.attr
,
5749 #ifdef CONFIG_ZONE_DMA
5750 &cache_dma_attr
.attr
,
5753 &remote_node_defrag_ratio_attr
.attr
,
5755 #ifdef CONFIG_SLUB_STATS
5756 &alloc_fastpath_attr
.attr
,
5757 &alloc_slowpath_attr
.attr
,
5758 &free_fastpath_attr
.attr
,
5759 &free_slowpath_attr
.attr
,
5760 &free_frozen_attr
.attr
,
5761 &free_add_partial_attr
.attr
,
5762 &free_remove_partial_attr
.attr
,
5763 &alloc_from_partial_attr
.attr
,
5764 &alloc_slab_attr
.attr
,
5765 &alloc_refill_attr
.attr
,
5766 &alloc_node_mismatch_attr
.attr
,
5767 &free_slab_attr
.attr
,
5768 &cpuslab_flush_attr
.attr
,
5769 &deactivate_full_attr
.attr
,
5770 &deactivate_empty_attr
.attr
,
5771 &deactivate_to_head_attr
.attr
,
5772 &deactivate_to_tail_attr
.attr
,
5773 &deactivate_remote_frees_attr
.attr
,
5774 &deactivate_bypass_attr
.attr
,
5775 &order_fallback_attr
.attr
,
5776 &cmpxchg_double_fail_attr
.attr
,
5777 &cmpxchg_double_cpu_fail_attr
.attr
,
5778 &cpu_partial_alloc_attr
.attr
,
5779 &cpu_partial_free_attr
.attr
,
5780 &cpu_partial_node_attr
.attr
,
5781 &cpu_partial_drain_attr
.attr
,
5783 #ifdef CONFIG_FAILSLAB
5784 &failslab_attr
.attr
,
5786 &usersize_attr
.attr
,
5791 static const struct attribute_group slab_attr_group
= {
5792 .attrs
= slab_attrs
,
5795 static ssize_t
slab_attr_show(struct kobject
*kobj
,
5796 struct attribute
*attr
,
5799 struct slab_attribute
*attribute
;
5800 struct kmem_cache
*s
;
5803 attribute
= to_slab_attr(attr
);
5806 if (!attribute
->show
)
5809 err
= attribute
->show(s
, buf
);
5814 static ssize_t
slab_attr_store(struct kobject
*kobj
,
5815 struct attribute
*attr
,
5816 const char *buf
, size_t len
)
5818 struct slab_attribute
*attribute
;
5819 struct kmem_cache
*s
;
5822 attribute
= to_slab_attr(attr
);
5825 if (!attribute
->store
)
5828 err
= attribute
->store(s
, buf
, len
);
5832 static void kmem_cache_release(struct kobject
*k
)
5834 slab_kmem_cache_release(to_slab(k
));
5837 static const struct sysfs_ops slab_sysfs_ops
= {
5838 .show
= slab_attr_show
,
5839 .store
= slab_attr_store
,
5842 static struct kobj_type slab_ktype
= {
5843 .sysfs_ops
= &slab_sysfs_ops
,
5844 .release
= kmem_cache_release
,
5847 static struct kset
*slab_kset
;
5849 static inline struct kset
*cache_kset(struct kmem_cache
*s
)
5854 #define ID_STR_LENGTH 64
5856 /* Create a unique string id for a slab cache:
5858 * Format :[flags-]size
5860 static char *create_unique_id(struct kmem_cache
*s
)
5862 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
5869 * First flags affecting slabcache operations. We will only
5870 * get here for aliasable slabs so we do not need to support
5871 * too many flags. The flags here must cover all flags that
5872 * are matched during merging to guarantee that the id is
5875 if (s
->flags
& SLAB_CACHE_DMA
)
5877 if (s
->flags
& SLAB_CACHE_DMA32
)
5879 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
5881 if (s
->flags
& SLAB_CONSISTENCY_CHECKS
)
5883 if (s
->flags
& SLAB_ACCOUNT
)
5887 p
+= sprintf(p
, "%07u", s
->size
);
5889 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
5893 static int sysfs_slab_add(struct kmem_cache
*s
)
5897 struct kset
*kset
= cache_kset(s
);
5898 int unmergeable
= slab_unmergeable(s
);
5901 kobject_init(&s
->kobj
, &slab_ktype
);
5905 if (!unmergeable
&& disable_higher_order_debug
&&
5906 (slub_debug
& DEBUG_METADATA_FLAGS
))
5911 * Slabcache can never be merged so we can use the name proper.
5912 * This is typically the case for debug situations. In that
5913 * case we can catch duplicate names easily.
5915 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
5919 * Create a unique name for the slab as a target
5922 name
= create_unique_id(s
);
5925 s
->kobj
.kset
= kset
;
5926 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, "%s", name
);
5930 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
5935 /* Setup first alias */
5936 sysfs_slab_alias(s
, s
->name
);
5943 kobject_del(&s
->kobj
);
5947 void sysfs_slab_unlink(struct kmem_cache
*s
)
5949 if (slab_state
>= FULL
)
5950 kobject_del(&s
->kobj
);
5953 void sysfs_slab_release(struct kmem_cache
*s
)
5955 if (slab_state
>= FULL
)
5956 kobject_put(&s
->kobj
);
5960 * Need to buffer aliases during bootup until sysfs becomes
5961 * available lest we lose that information.
5963 struct saved_alias
{
5964 struct kmem_cache
*s
;
5966 struct saved_alias
*next
;
5969 static struct saved_alias
*alias_list
;
5971 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5973 struct saved_alias
*al
;
5975 if (slab_state
== FULL
) {
5977 * If we have a leftover link then remove it.
5979 sysfs_remove_link(&slab_kset
->kobj
, name
);
5980 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5983 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5989 al
->next
= alias_list
;
5994 static int __init
slab_sysfs_init(void)
5996 struct kmem_cache
*s
;
5999 mutex_lock(&slab_mutex
);
6001 slab_kset
= kset_create_and_add("slab", NULL
, kernel_kobj
);
6003 mutex_unlock(&slab_mutex
);
6004 pr_err("Cannot register slab subsystem.\n");
6010 list_for_each_entry(s
, &slab_caches
, list
) {
6011 err
= sysfs_slab_add(s
);
6013 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
6017 while (alias_list
) {
6018 struct saved_alias
*al
= alias_list
;
6020 alias_list
= alias_list
->next
;
6021 err
= sysfs_slab_alias(al
->s
, al
->name
);
6023 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
6028 mutex_unlock(&slab_mutex
);
6032 __initcall(slab_sysfs_init
);
6033 #endif /* CONFIG_SYSFS */
6035 #if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
6036 static int slab_debugfs_show(struct seq_file
*seq
, void *v
)
6040 unsigned int idx
= *(unsigned int *)v
;
6041 struct loc_track
*t
= seq
->private;
6043 if (idx
< t
->count
) {
6046 seq_printf(seq
, "%7ld ", l
->count
);
6049 seq_printf(seq
, "%pS", (void *)l
->addr
);
6051 seq_puts(seq
, "<not-available>");
6053 if (l
->sum_time
!= l
->min_time
) {
6054 seq_printf(seq
, " age=%ld/%llu/%ld",
6055 l
->min_time
, div_u64(l
->sum_time
, l
->count
),
6058 seq_printf(seq
, " age=%ld", l
->min_time
);
6060 if (l
->min_pid
!= l
->max_pid
)
6061 seq_printf(seq
, " pid=%ld-%ld", l
->min_pid
, l
->max_pid
);
6063 seq_printf(seq
, " pid=%ld",
6066 if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l
->cpus
)))
6067 seq_printf(seq
, " cpus=%*pbl",
6068 cpumask_pr_args(to_cpumask(l
->cpus
)));
6070 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
))
6071 seq_printf(seq
, " nodes=%*pbl",
6072 nodemask_pr_args(&l
->nodes
));
6074 seq_puts(seq
, "\n");
6077 if (!idx
&& !t
->count
)
6078 seq_puts(seq
, "No data\n");
6083 static void slab_debugfs_stop(struct seq_file
*seq
, void *v
)
6087 static void *slab_debugfs_next(struct seq_file
*seq
, void *v
, loff_t
*ppos
)
6089 struct loc_track
*t
= seq
->private;
6093 if (*ppos
<= t
->count
)
6099 static void *slab_debugfs_start(struct seq_file
*seq
, loff_t
*ppos
)
6104 static const struct seq_operations slab_debugfs_sops
= {
6105 .start
= slab_debugfs_start
,
6106 .next
= slab_debugfs_next
,
6107 .stop
= slab_debugfs_stop
,
6108 .show
= slab_debugfs_show
,
6111 static int slab_debug_trace_open(struct inode
*inode
, struct file
*filep
)
6114 struct kmem_cache_node
*n
;
6115 enum track_item alloc
;
6117 struct loc_track
*t
= __seq_open_private(filep
, &slab_debugfs_sops
,
6118 sizeof(struct loc_track
));
6119 struct kmem_cache
*s
= file_inode(filep
)->i_private
;
6120 unsigned long *obj_map
;
6125 obj_map
= bitmap_alloc(oo_objects(s
->oo
), GFP_KERNEL
);
6127 seq_release_private(inode
, filep
);
6131 if (strcmp(filep
->f_path
.dentry
->d_name
.name
, "alloc_traces") == 0)
6132 alloc
= TRACK_ALLOC
;
6136 if (!alloc_loc_track(t
, PAGE_SIZE
/ sizeof(struct location
), GFP_KERNEL
)) {
6137 bitmap_free(obj_map
);
6138 seq_release_private(inode
, filep
);
6142 for_each_kmem_cache_node(s
, node
, n
) {
6143 unsigned long flags
;
6146 if (!atomic_long_read(&n
->nr_slabs
))
6149 spin_lock_irqsave(&n
->list_lock
, flags
);
6150 list_for_each_entry(page
, &n
->partial
, slab_list
)
6151 process_slab(t
, s
, page
, alloc
, obj_map
);
6152 list_for_each_entry(page
, &n
->full
, slab_list
)
6153 process_slab(t
, s
, page
, alloc
, obj_map
);
6154 spin_unlock_irqrestore(&n
->list_lock
, flags
);
6157 bitmap_free(obj_map
);
6161 static int slab_debug_trace_release(struct inode
*inode
, struct file
*file
)
6163 struct seq_file
*seq
= file
->private_data
;
6164 struct loc_track
*t
= seq
->private;
6167 return seq_release_private(inode
, file
);
6170 static const struct file_operations slab_debugfs_fops
= {
6171 .open
= slab_debug_trace_open
,
6173 .llseek
= seq_lseek
,
6174 .release
= slab_debug_trace_release
,
6177 static void debugfs_slab_add(struct kmem_cache
*s
)
6179 struct dentry
*slab_cache_dir
;
6181 if (unlikely(!slab_debugfs_root
))
6184 slab_cache_dir
= debugfs_create_dir(s
->name
, slab_debugfs_root
);
6186 debugfs_create_file("alloc_traces", 0400,
6187 slab_cache_dir
, s
, &slab_debugfs_fops
);
6189 debugfs_create_file("free_traces", 0400,
6190 slab_cache_dir
, s
, &slab_debugfs_fops
);
6193 void debugfs_slab_release(struct kmem_cache
*s
)
6195 debugfs_remove_recursive(debugfs_lookup(s
->name
, slab_debugfs_root
));
6198 static int __init
slab_debugfs_init(void)
6200 struct kmem_cache
*s
;
6202 slab_debugfs_root
= debugfs_create_dir("slab", NULL
);
6204 list_for_each_entry(s
, &slab_caches
, list
)
6205 if (s
->flags
& SLAB_STORE_USER
)
6206 debugfs_slab_add(s
);
6211 __initcall(slab_debugfs_init
);
6214 * The /proc/slabinfo ABI
6216 #ifdef CONFIG_SLUB_DEBUG
6217 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
)
6219 unsigned long nr_slabs
= 0;
6220 unsigned long nr_objs
= 0;
6221 unsigned long nr_free
= 0;
6223 struct kmem_cache_node
*n
;
6225 for_each_kmem_cache_node(s
, node
, n
) {
6226 nr_slabs
+= node_nr_slabs(n
);
6227 nr_objs
+= node_nr_objs(n
);
6228 nr_free
+= count_partial(n
, count_free
);
6231 sinfo
->active_objs
= nr_objs
- nr_free
;
6232 sinfo
->num_objs
= nr_objs
;
6233 sinfo
->active_slabs
= nr_slabs
;
6234 sinfo
->num_slabs
= nr_slabs
;
6235 sinfo
->objects_per_slab
= oo_objects(s
->oo
);
6236 sinfo
->cache_order
= oo_order(s
->oo
);
6239 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
)
6243 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
6244 size_t count
, loff_t
*ppos
)
6248 #endif /* CONFIG_SLUB_DEBUG */