2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
5 * The allocator synchronizes using per slab locks or atomic operatios
6 * and only uses a centralized lock to manage a pool of partial slabs.
8 * (C) 2007 SGI, Christoph Lameter
9 * (C) 2011 Linux Foundation, Christoph Lameter
13 #include <linux/swap.h> /* struct reclaim_state */
14 #include <linux/module.h>
15 #include <linux/bit_spinlock.h>
16 #include <linux/interrupt.h>
17 #include <linux/bitops.h>
18 #include <linux/slab.h>
20 #include <linux/proc_fs.h>
21 #include <linux/notifier.h>
22 #include <linux/seq_file.h>
23 #include <linux/kasan.h>
24 #include <linux/kmemcheck.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/memory.h>
32 #include <linux/math64.h>
33 #include <linux/fault-inject.h>
34 #include <linux/stacktrace.h>
35 #include <linux/prefetch.h>
36 #include <linux/memcontrol.h>
38 #include <trace/events/kmem.h>
44 * 1. slab_mutex (Global Mutex)
46 * 3. slab_lock(page) (Only on some arches and for debugging)
50 * The role of the slab_mutex is to protect the list of all the slabs
51 * and to synchronize major metadata changes to slab cache structures.
53 * The slab_lock is only used for debugging and on arches that do not
54 * have the ability to do a cmpxchg_double. It only protects the second
55 * double word in the page struct. Meaning
56 * A. page->freelist -> List of object free in a page
57 * B. page->counters -> Counters of objects
58 * C. page->frozen -> frozen state
60 * If a slab is frozen then it is exempt from list management. It is not
61 * on any list. The processor that froze the slab is the one who can
62 * perform list operations on the page. Other processors may put objects
63 * onto the freelist but the processor that froze the slab is the only
64 * one that can retrieve the objects from the page's freelist.
66 * The list_lock protects the partial and full list on each node and
67 * the partial slab counter. If taken then no new slabs may be added or
68 * removed from the lists nor make the number of partial slabs be modified.
69 * (Note that the total number of slabs is an atomic value that may be
70 * modified without taking the list lock).
72 * The list_lock is a centralized lock and thus we avoid taking it as
73 * much as possible. As long as SLUB does not have to handle partial
74 * slabs, operations can continue without any centralized lock. F.e.
75 * allocating a long series of objects that fill up slabs does not require
77 * Interrupts are disabled during allocation and deallocation in order to
78 * make the slab allocator safe to use in the context of an irq. In addition
79 * interrupts are disabled to ensure that the processor does not change
80 * while handling per_cpu slabs, due to kernel preemption.
82 * SLUB assigns one slab for allocation to each processor.
83 * Allocations only occur from these slabs called cpu slabs.
85 * Slabs with free elements are kept on a partial list and during regular
86 * operations no list for full slabs is used. If an object in a full slab is
87 * freed then the slab will show up again on the partial lists.
88 * We track full slabs for debugging purposes though because otherwise we
89 * cannot scan all objects.
91 * Slabs are freed when they become empty. Teardown and setup is
92 * minimal so we rely on the page allocators per cpu caches for
93 * fast frees and allocs.
95 * Overloading of page flags that are otherwise used for LRU management.
97 * PageActive The slab is frozen and exempt from list processing.
98 * This means that the slab is dedicated to a purpose
99 * such as satisfying allocations for a specific
100 * processor. Objects may be freed in the slab while
101 * it is frozen but slab_free will then skip the usual
102 * list operations. It is up to the processor holding
103 * the slab to integrate the slab into the slab lists
104 * when the slab is no longer needed.
106 * One use of this flag is to mark slabs that are
107 * used for allocations. Then such a slab becomes a cpu
108 * slab. The cpu slab may be equipped with an additional
109 * freelist that allows lockless access to
110 * free objects in addition to the regular freelist
111 * that requires the slab lock.
113 * PageError Slab requires special handling due to debug
114 * options set. This moves slab handling out of
115 * the fast path and disables lockless freelists.
118 static inline int kmem_cache_debug(struct kmem_cache
*s
)
120 #ifdef CONFIG_SLUB_DEBUG
121 return unlikely(s
->flags
& SLAB_DEBUG_FLAGS
);
127 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache
*s
)
129 #ifdef CONFIG_SLUB_CPU_PARTIAL
130 return !kmem_cache_debug(s
);
137 * Issues still to be resolved:
139 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
141 * - Variable sizing of the per node arrays
144 /* Enable to test recovery from slab corruption on boot */
145 #undef SLUB_RESILIENCY_TEST
147 /* Enable to log cmpxchg failures */
148 #undef SLUB_DEBUG_CMPXCHG
151 * Mininum number of partial slabs. These will be left on the partial
152 * lists even if they are empty. kmem_cache_shrink may reclaim them.
154 #define MIN_PARTIAL 5
157 * Maximum number of desirable partial slabs.
158 * The existence of more partial slabs makes kmem_cache_shrink
159 * sort the partial list by the number of objects in use.
161 #define MAX_PARTIAL 10
163 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
164 SLAB_POISON | SLAB_STORE_USER)
167 * Debugging flags that require metadata to be stored in the slab. These get
168 * disabled when slub_debug=O is used and a cache's min order increases with
171 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
174 #define OO_MASK ((1 << OO_SHIFT) - 1)
175 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
177 /* Internal SLUB flags */
178 #define __OBJECT_POISON 0x80000000UL /* Poison object */
179 #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
182 static struct notifier_block slab_notifier
;
186 * Tracking user of a slab.
188 #define TRACK_ADDRS_COUNT 16
190 unsigned long addr
; /* Called from address */
191 #ifdef CONFIG_STACKTRACE
192 unsigned long addrs
[TRACK_ADDRS_COUNT
]; /* Called from address */
194 int cpu
; /* Was running on cpu */
195 int pid
; /* Pid context */
196 unsigned long when
; /* When did the operation occur */
199 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
202 static int sysfs_slab_add(struct kmem_cache
*);
203 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
204 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
);
206 static inline int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
207 static inline int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
)
209 static inline void memcg_propagate_slab_attrs(struct kmem_cache
*s
) { }
212 static inline void stat(const struct kmem_cache
*s
, enum stat_item si
)
214 #ifdef CONFIG_SLUB_STATS
216 * The rmw is racy on a preemptible kernel but this is acceptable, so
217 * avoid this_cpu_add()'s irq-disable overhead.
219 raw_cpu_inc(s
->cpu_slab
->stat
[si
]);
223 /********************************************************************
224 * Core slab cache functions
225 *******************************************************************/
227 /* Verify that a pointer has an address that is valid within a slab page */
228 static inline int check_valid_pointer(struct kmem_cache
*s
,
229 struct page
*page
, const void *object
)
236 base
= page_address(page
);
237 if (object
< base
|| object
>= base
+ page
->objects
* s
->size
||
238 (object
- base
) % s
->size
) {
245 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
247 return *(void **)(object
+ s
->offset
);
250 static void prefetch_freepointer(const struct kmem_cache
*s
, void *object
)
252 prefetch(object
+ s
->offset
);
255 static inline void *get_freepointer_safe(struct kmem_cache
*s
, void *object
)
259 #ifdef CONFIG_DEBUG_PAGEALLOC
260 probe_kernel_read(&p
, (void **)(object
+ s
->offset
), sizeof(p
));
262 p
= get_freepointer(s
, object
);
267 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
269 *(void **)(object
+ s
->offset
) = fp
;
272 /* Loop over all objects in a slab */
273 #define for_each_object(__p, __s, __addr, __objects) \
274 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
277 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
278 for (__p = (__addr), __idx = 1; __idx <= __objects;\
279 __p += (__s)->size, __idx++)
281 /* Determine object index from a given position */
282 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
284 return (p
- addr
) / s
->size
;
287 static inline size_t slab_ksize(const struct kmem_cache
*s
)
289 #ifdef CONFIG_SLUB_DEBUG
291 * Debugging requires use of the padding between object
292 * and whatever may come after it.
294 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
295 return s
->object_size
;
299 * If we have the need to store the freelist pointer
300 * back there or track user information then we can
301 * only use the space before that information.
303 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
306 * Else we can use all the padding etc for the allocation
311 static inline int order_objects(int order
, unsigned long size
, int reserved
)
313 return ((PAGE_SIZE
<< order
) - reserved
) / size
;
316 static inline struct kmem_cache_order_objects
oo_make(int order
,
317 unsigned long size
, int reserved
)
319 struct kmem_cache_order_objects x
= {
320 (order
<< OO_SHIFT
) + order_objects(order
, size
, reserved
)
326 static inline int oo_order(struct kmem_cache_order_objects x
)
328 return x
.x
>> OO_SHIFT
;
331 static inline int oo_objects(struct kmem_cache_order_objects x
)
333 return x
.x
& OO_MASK
;
337 * Per slab locking using the pagelock
339 static __always_inline
void slab_lock(struct page
*page
)
341 bit_spin_lock(PG_locked
, &page
->flags
);
344 static __always_inline
void slab_unlock(struct page
*page
)
346 __bit_spin_unlock(PG_locked
, &page
->flags
);
349 static inline void set_page_slub_counters(struct page
*page
, unsigned long counters_new
)
352 tmp
.counters
= counters_new
;
354 * page->counters can cover frozen/inuse/objects as well
355 * as page->_count. If we assign to ->counters directly
356 * we run the risk of losing updates to page->_count, so
357 * be careful and only assign to the fields we need.
359 page
->frozen
= tmp
.frozen
;
360 page
->inuse
= tmp
.inuse
;
361 page
->objects
= tmp
.objects
;
364 /* Interrupts must be disabled (for the fallback code to work right) */
365 static inline bool __cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
366 void *freelist_old
, unsigned long counters_old
,
367 void *freelist_new
, unsigned long counters_new
,
370 VM_BUG_ON(!irqs_disabled());
371 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
372 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
373 if (s
->flags
& __CMPXCHG_DOUBLE
) {
374 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
375 freelist_old
, counters_old
,
376 freelist_new
, counters_new
))
382 if (page
->freelist
== freelist_old
&&
383 page
->counters
== counters_old
) {
384 page
->freelist
= freelist_new
;
385 set_page_slub_counters(page
, counters_new
);
393 stat(s
, CMPXCHG_DOUBLE_FAIL
);
395 #ifdef SLUB_DEBUG_CMPXCHG
396 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
402 static inline bool cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
403 void *freelist_old
, unsigned long counters_old
,
404 void *freelist_new
, unsigned long counters_new
,
407 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
408 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
409 if (s
->flags
& __CMPXCHG_DOUBLE
) {
410 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
411 freelist_old
, counters_old
,
412 freelist_new
, counters_new
))
419 local_irq_save(flags
);
421 if (page
->freelist
== freelist_old
&&
422 page
->counters
== counters_old
) {
423 page
->freelist
= freelist_new
;
424 set_page_slub_counters(page
, counters_new
);
426 local_irq_restore(flags
);
430 local_irq_restore(flags
);
434 stat(s
, CMPXCHG_DOUBLE_FAIL
);
436 #ifdef SLUB_DEBUG_CMPXCHG
437 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
443 #ifdef CONFIG_SLUB_DEBUG
445 * Determine a map of object in use on a page.
447 * Node listlock must be held to guarantee that the page does
448 * not vanish from under us.
450 static void get_map(struct kmem_cache
*s
, struct page
*page
, unsigned long *map
)
453 void *addr
= page_address(page
);
455 for (p
= page
->freelist
; p
; p
= get_freepointer(s
, p
))
456 set_bit(slab_index(p
, s
, addr
), map
);
462 #if defined(CONFIG_SLUB_DEBUG_ON)
463 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
464 #elif defined(CONFIG_KASAN)
465 static int slub_debug
= SLAB_STORE_USER
;
467 static int slub_debug
;
470 static char *slub_debug_slabs
;
471 static int disable_higher_order_debug
;
474 * slub is about to manipulate internal object metadata. This memory lies
475 * outside the range of the allocated object, so accessing it would normally
476 * be reported by kasan as a bounds error. metadata_access_enable() is used
477 * to tell kasan that these accesses are OK.
479 static inline void metadata_access_enable(void)
481 kasan_disable_current();
484 static inline void metadata_access_disable(void)
486 kasan_enable_current();
492 static void print_section(char *text
, u8
*addr
, unsigned int length
)
494 metadata_access_enable();
495 print_hex_dump(KERN_ERR
, text
, DUMP_PREFIX_ADDRESS
, 16, 1, addr
,
497 metadata_access_disable();
500 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
501 enum track_item alloc
)
506 p
= object
+ s
->offset
+ sizeof(void *);
508 p
= object
+ s
->inuse
;
513 static void set_track(struct kmem_cache
*s
, void *object
,
514 enum track_item alloc
, unsigned long addr
)
516 struct track
*p
= get_track(s
, object
, alloc
);
519 #ifdef CONFIG_STACKTRACE
520 struct stack_trace trace
;
523 trace
.nr_entries
= 0;
524 trace
.max_entries
= TRACK_ADDRS_COUNT
;
525 trace
.entries
= p
->addrs
;
527 metadata_access_enable();
528 save_stack_trace(&trace
);
529 metadata_access_disable();
531 /* See rant in lockdep.c */
532 if (trace
.nr_entries
!= 0 &&
533 trace
.entries
[trace
.nr_entries
- 1] == ULONG_MAX
)
536 for (i
= trace
.nr_entries
; i
< TRACK_ADDRS_COUNT
; i
++)
540 p
->cpu
= smp_processor_id();
541 p
->pid
= current
->pid
;
544 memset(p
, 0, sizeof(struct track
));
547 static void init_tracking(struct kmem_cache
*s
, void *object
)
549 if (!(s
->flags
& SLAB_STORE_USER
))
552 set_track(s
, object
, TRACK_FREE
, 0UL);
553 set_track(s
, object
, TRACK_ALLOC
, 0UL);
556 static void print_track(const char *s
, struct track
*t
)
561 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
562 s
, (void *)t
->addr
, jiffies
- t
->when
, t
->cpu
, t
->pid
);
563 #ifdef CONFIG_STACKTRACE
566 for (i
= 0; i
< TRACK_ADDRS_COUNT
; i
++)
568 pr_err("\t%pS\n", (void *)t
->addrs
[i
]);
575 static void print_tracking(struct kmem_cache
*s
, void *object
)
577 if (!(s
->flags
& SLAB_STORE_USER
))
580 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
581 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
584 static void print_page_info(struct page
*page
)
586 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
587 page
, page
->objects
, page
->inuse
, page
->freelist
, page
->flags
);
591 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
593 struct va_format vaf
;
599 pr_err("=============================================================================\n");
600 pr_err("BUG %s (%s): %pV\n", s
->name
, print_tainted(), &vaf
);
601 pr_err("-----------------------------------------------------------------------------\n\n");
603 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
607 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
609 struct va_format vaf
;
615 pr_err("FIX %s: %pV\n", s
->name
, &vaf
);
619 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
621 unsigned int off
; /* Offset of last byte */
622 u8
*addr
= page_address(page
);
624 print_tracking(s
, p
);
626 print_page_info(page
);
628 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
629 p
, p
- addr
, get_freepointer(s
, p
));
632 print_section("Bytes b4 ", p
- 16, 16);
634 print_section("Object ", p
, min_t(unsigned long, s
->object_size
,
636 if (s
->flags
& SLAB_RED_ZONE
)
637 print_section("Redzone ", p
+ s
->object_size
,
638 s
->inuse
- s
->object_size
);
641 off
= s
->offset
+ sizeof(void *);
645 if (s
->flags
& SLAB_STORE_USER
)
646 off
+= 2 * sizeof(struct track
);
649 /* Beginning of the filler is the free pointer */
650 print_section("Padding ", p
+ off
, s
->size
- off
);
655 void object_err(struct kmem_cache
*s
, struct page
*page
,
656 u8
*object
, char *reason
)
658 slab_bug(s
, "%s", reason
);
659 print_trailer(s
, page
, object
);
662 static void slab_err(struct kmem_cache
*s
, struct page
*page
,
663 const char *fmt
, ...)
669 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
671 slab_bug(s
, "%s", buf
);
672 print_page_info(page
);
676 static void init_object(struct kmem_cache
*s
, void *object
, u8 val
)
680 if (s
->flags
& __OBJECT_POISON
) {
681 memset(p
, POISON_FREE
, s
->object_size
- 1);
682 p
[s
->object_size
- 1] = POISON_END
;
685 if (s
->flags
& SLAB_RED_ZONE
)
686 memset(p
+ s
->object_size
, val
, s
->inuse
- s
->object_size
);
689 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
690 void *from
, void *to
)
692 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
693 memset(from
, data
, to
- from
);
696 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
697 u8
*object
, char *what
,
698 u8
*start
, unsigned int value
, unsigned int bytes
)
703 metadata_access_enable();
704 fault
= memchr_inv(start
, value
, bytes
);
705 metadata_access_disable();
710 while (end
> fault
&& end
[-1] == value
)
713 slab_bug(s
, "%s overwritten", what
);
714 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
715 fault
, end
- 1, fault
[0], value
);
716 print_trailer(s
, page
, object
);
718 restore_bytes(s
, what
, value
, fault
, end
);
726 * Bytes of the object to be managed.
727 * If the freepointer may overlay the object then the free
728 * pointer is the first word of the object.
730 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
733 * object + s->object_size
734 * Padding to reach word boundary. This is also used for Redzoning.
735 * Padding is extended by another word if Redzoning is enabled and
736 * object_size == inuse.
738 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
739 * 0xcc (RED_ACTIVE) for objects in use.
742 * Meta data starts here.
744 * A. Free pointer (if we cannot overwrite object on free)
745 * B. Tracking data for SLAB_STORE_USER
746 * C. Padding to reach required alignment boundary or at mininum
747 * one word if debugging is on to be able to detect writes
748 * before the word boundary.
750 * Padding is done using 0x5a (POISON_INUSE)
753 * Nothing is used beyond s->size.
755 * If slabcaches are merged then the object_size and inuse boundaries are mostly
756 * ignored. And therefore no slab options that rely on these boundaries
757 * may be used with merged slabcaches.
760 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
762 unsigned long off
= s
->inuse
; /* The end of info */
765 /* Freepointer is placed after the object. */
766 off
+= sizeof(void *);
768 if (s
->flags
& SLAB_STORE_USER
)
769 /* We also have user information there */
770 off
+= 2 * sizeof(struct track
);
775 return check_bytes_and_report(s
, page
, p
, "Object padding",
776 p
+ off
, POISON_INUSE
, s
->size
- off
);
779 /* Check the pad bytes at the end of a slab page */
780 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
788 if (!(s
->flags
& SLAB_POISON
))
791 start
= page_address(page
);
792 length
= (PAGE_SIZE
<< compound_order(page
)) - s
->reserved
;
793 end
= start
+ length
;
794 remainder
= length
% s
->size
;
798 metadata_access_enable();
799 fault
= memchr_inv(end
- remainder
, POISON_INUSE
, remainder
);
800 metadata_access_disable();
803 while (end
> fault
&& end
[-1] == POISON_INUSE
)
806 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
807 print_section("Padding ", end
- remainder
, remainder
);
809 restore_bytes(s
, "slab padding", POISON_INUSE
, end
- remainder
, end
);
813 static int check_object(struct kmem_cache
*s
, struct page
*page
,
814 void *object
, u8 val
)
817 u8
*endobject
= object
+ s
->object_size
;
819 if (s
->flags
& SLAB_RED_ZONE
) {
820 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
821 endobject
, val
, s
->inuse
- s
->object_size
))
824 if ((s
->flags
& SLAB_POISON
) && s
->object_size
< s
->inuse
) {
825 check_bytes_and_report(s
, page
, p
, "Alignment padding",
826 endobject
, POISON_INUSE
,
827 s
->inuse
- s
->object_size
);
831 if (s
->flags
& SLAB_POISON
) {
832 if (val
!= SLUB_RED_ACTIVE
&& (s
->flags
& __OBJECT_POISON
) &&
833 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
834 POISON_FREE
, s
->object_size
- 1) ||
835 !check_bytes_and_report(s
, page
, p
, "Poison",
836 p
+ s
->object_size
- 1, POISON_END
, 1)))
839 * check_pad_bytes cleans up on its own.
841 check_pad_bytes(s
, page
, p
);
844 if (!s
->offset
&& val
== SLUB_RED_ACTIVE
)
846 * Object and freepointer overlap. Cannot check
847 * freepointer while object is allocated.
851 /* Check free pointer validity */
852 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
853 object_err(s
, page
, p
, "Freepointer corrupt");
855 * No choice but to zap it and thus lose the remainder
856 * of the free objects in this slab. May cause
857 * another error because the object count is now wrong.
859 set_freepointer(s
, p
, NULL
);
865 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
869 VM_BUG_ON(!irqs_disabled());
871 if (!PageSlab(page
)) {
872 slab_err(s
, page
, "Not a valid slab page");
876 maxobj
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
877 if (page
->objects
> maxobj
) {
878 slab_err(s
, page
, "objects %u > max %u",
879 page
->objects
, maxobj
);
882 if (page
->inuse
> page
->objects
) {
883 slab_err(s
, page
, "inuse %u > max %u",
884 page
->inuse
, page
->objects
);
887 /* Slab_pad_check fixes things up after itself */
888 slab_pad_check(s
, page
);
893 * Determine if a certain object on a page is on the freelist. Must hold the
894 * slab lock to guarantee that the chains are in a consistent state.
896 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
904 while (fp
&& nr
<= page
->objects
) {
907 if (!check_valid_pointer(s
, page
, fp
)) {
909 object_err(s
, page
, object
,
910 "Freechain corrupt");
911 set_freepointer(s
, object
, NULL
);
913 slab_err(s
, page
, "Freepointer corrupt");
914 page
->freelist
= NULL
;
915 page
->inuse
= page
->objects
;
916 slab_fix(s
, "Freelist cleared");
922 fp
= get_freepointer(s
, object
);
926 max_objects
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
927 if (max_objects
> MAX_OBJS_PER_PAGE
)
928 max_objects
= MAX_OBJS_PER_PAGE
;
930 if (page
->objects
!= max_objects
) {
931 slab_err(s
, page
, "Wrong number of objects. Found %d but "
932 "should be %d", page
->objects
, max_objects
);
933 page
->objects
= max_objects
;
934 slab_fix(s
, "Number of objects adjusted.");
936 if (page
->inuse
!= page
->objects
- nr
) {
937 slab_err(s
, page
, "Wrong object count. Counter is %d but "
938 "counted were %d", page
->inuse
, page
->objects
- nr
);
939 page
->inuse
= page
->objects
- nr
;
940 slab_fix(s
, "Object count adjusted.");
942 return search
== NULL
;
945 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
,
948 if (s
->flags
& SLAB_TRACE
) {
949 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
951 alloc
? "alloc" : "free",
956 print_section("Object ", (void *)object
,
964 * Tracking of fully allocated slabs for debugging purposes.
966 static void add_full(struct kmem_cache
*s
,
967 struct kmem_cache_node
*n
, struct page
*page
)
969 if (!(s
->flags
& SLAB_STORE_USER
))
972 lockdep_assert_held(&n
->list_lock
);
973 list_add(&page
->lru
, &n
->full
);
976 static void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
, struct page
*page
)
978 if (!(s
->flags
& SLAB_STORE_USER
))
981 lockdep_assert_held(&n
->list_lock
);
982 list_del(&page
->lru
);
985 /* Tracking of the number of slabs for debugging purposes */
986 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
988 struct kmem_cache_node
*n
= get_node(s
, node
);
990 return atomic_long_read(&n
->nr_slabs
);
993 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
995 return atomic_long_read(&n
->nr_slabs
);
998 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1000 struct kmem_cache_node
*n
= get_node(s
, node
);
1003 * May be called early in order to allocate a slab for the
1004 * kmem_cache_node structure. Solve the chicken-egg
1005 * dilemma by deferring the increment of the count during
1006 * bootstrap (see early_kmem_cache_node_alloc).
1009 atomic_long_inc(&n
->nr_slabs
);
1010 atomic_long_add(objects
, &n
->total_objects
);
1013 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1015 struct kmem_cache_node
*n
= get_node(s
, node
);
1017 atomic_long_dec(&n
->nr_slabs
);
1018 atomic_long_sub(objects
, &n
->total_objects
);
1021 /* Object debug checks for alloc/free paths */
1022 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
1025 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
1028 init_object(s
, object
, SLUB_RED_INACTIVE
);
1029 init_tracking(s
, object
);
1032 static noinline
int alloc_debug_processing(struct kmem_cache
*s
,
1034 void *object
, unsigned long addr
)
1036 if (!check_slab(s
, page
))
1039 if (!check_valid_pointer(s
, page
, object
)) {
1040 object_err(s
, page
, object
, "Freelist Pointer check fails");
1044 if (!check_object(s
, page
, object
, SLUB_RED_INACTIVE
))
1047 /* Success perform special debug activities for allocs */
1048 if (s
->flags
& SLAB_STORE_USER
)
1049 set_track(s
, object
, TRACK_ALLOC
, addr
);
1050 trace(s
, page
, object
, 1);
1051 init_object(s
, object
, SLUB_RED_ACTIVE
);
1055 if (PageSlab(page
)) {
1057 * If this is a slab page then lets do the best we can
1058 * to avoid issues in the future. Marking all objects
1059 * as used avoids touching the remaining objects.
1061 slab_fix(s
, "Marking all objects used");
1062 page
->inuse
= page
->objects
;
1063 page
->freelist
= NULL
;
1068 static noinline
struct kmem_cache_node
*free_debug_processing(
1069 struct kmem_cache
*s
, struct page
*page
, void *object
,
1070 unsigned long addr
, unsigned long *flags
)
1072 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1074 spin_lock_irqsave(&n
->list_lock
, *flags
);
1077 if (!check_slab(s
, page
))
1080 if (!check_valid_pointer(s
, page
, object
)) {
1081 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
1085 if (on_freelist(s
, page
, object
)) {
1086 object_err(s
, page
, object
, "Object already free");
1090 if (!check_object(s
, page
, object
, SLUB_RED_ACTIVE
))
1093 if (unlikely(s
!= page
->slab_cache
)) {
1094 if (!PageSlab(page
)) {
1095 slab_err(s
, page
, "Attempt to free object(0x%p) "
1096 "outside of slab", object
);
1097 } else if (!page
->slab_cache
) {
1098 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1102 object_err(s
, page
, object
,
1103 "page slab pointer corrupt.");
1107 if (s
->flags
& SLAB_STORE_USER
)
1108 set_track(s
, object
, TRACK_FREE
, addr
);
1109 trace(s
, page
, object
, 0);
1110 init_object(s
, object
, SLUB_RED_INACTIVE
);
1114 * Keep node_lock to preserve integrity
1115 * until the object is actually freed
1121 spin_unlock_irqrestore(&n
->list_lock
, *flags
);
1122 slab_fix(s
, "Object at 0x%p not freed", object
);
1126 static int __init
setup_slub_debug(char *str
)
1128 slub_debug
= DEBUG_DEFAULT_FLAGS
;
1129 if (*str
++ != '=' || !*str
)
1131 * No options specified. Switch on full debugging.
1137 * No options but restriction on slabs. This means full
1138 * debugging for slabs matching a pattern.
1145 * Switch off all debugging measures.
1150 * Determine which debug features should be switched on
1152 for (; *str
&& *str
!= ','; str
++) {
1153 switch (tolower(*str
)) {
1155 slub_debug
|= SLAB_DEBUG_FREE
;
1158 slub_debug
|= SLAB_RED_ZONE
;
1161 slub_debug
|= SLAB_POISON
;
1164 slub_debug
|= SLAB_STORE_USER
;
1167 slub_debug
|= SLAB_TRACE
;
1170 slub_debug
|= SLAB_FAILSLAB
;
1174 * Avoid enabling debugging on caches if its minimum
1175 * order would increase as a result.
1177 disable_higher_order_debug
= 1;
1180 pr_err("slub_debug option '%c' unknown. skipped\n",
1187 slub_debug_slabs
= str
+ 1;
1192 __setup("slub_debug", setup_slub_debug
);
1194 unsigned long kmem_cache_flags(unsigned long object_size
,
1195 unsigned long flags
, const char *name
,
1196 void (*ctor
)(void *))
1199 * Enable debugging if selected on the kernel commandline.
1201 if (slub_debug
&& (!slub_debug_slabs
|| (name
&&
1202 !strncmp(slub_debug_slabs
, name
, strlen(slub_debug_slabs
)))))
1203 flags
|= slub_debug
;
1208 static inline void setup_object_debug(struct kmem_cache
*s
,
1209 struct page
*page
, void *object
) {}
1211 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1212 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1214 static inline struct kmem_cache_node
*free_debug_processing(
1215 struct kmem_cache
*s
, struct page
*page
, void *object
,
1216 unsigned long addr
, unsigned long *flags
) { return NULL
; }
1218 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1220 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1221 void *object
, u8 val
) { return 1; }
1222 static inline void add_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1223 struct page
*page
) {}
1224 static inline void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1225 struct page
*page
) {}
1226 unsigned long kmem_cache_flags(unsigned long object_size
,
1227 unsigned long flags
, const char *name
,
1228 void (*ctor
)(void *))
1232 #define slub_debug 0
1234 #define disable_higher_order_debug 0
1236 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1238 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1240 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
,
1242 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
,
1245 #endif /* CONFIG_SLUB_DEBUG */
1248 * Hooks for other subsystems that check memory allocations. In a typical
1249 * production configuration these hooks all should produce no code at all.
1251 static inline void kmalloc_large_node_hook(void *ptr
, size_t size
, gfp_t flags
)
1253 kmemleak_alloc(ptr
, size
, 1, flags
);
1254 kasan_kmalloc_large(ptr
, size
);
1257 static inline void kfree_hook(const void *x
)
1260 kasan_kfree_large(x
);
1263 static inline struct kmem_cache
*slab_pre_alloc_hook(struct kmem_cache
*s
,
1266 flags
&= gfp_allowed_mask
;
1267 lockdep_trace_alloc(flags
);
1268 might_sleep_if(flags
& __GFP_WAIT
);
1270 if (should_failslab(s
->object_size
, flags
, s
->flags
))
1273 return memcg_kmem_get_cache(s
, flags
);
1276 static inline void slab_post_alloc_hook(struct kmem_cache
*s
,
1277 gfp_t flags
, void *object
)
1279 flags
&= gfp_allowed_mask
;
1280 kmemcheck_slab_alloc(s
, flags
, object
, slab_ksize(s
));
1281 kmemleak_alloc_recursive(object
, s
->object_size
, 1, s
->flags
, flags
);
1282 memcg_kmem_put_cache(s
);
1283 kasan_slab_alloc(s
, object
);
1286 static inline void slab_free_hook(struct kmem_cache
*s
, void *x
)
1288 kmemleak_free_recursive(x
, s
->flags
);
1291 * Trouble is that we may no longer disable interrupts in the fast path
1292 * So in order to make the debug calls that expect irqs to be
1293 * disabled we need to disable interrupts temporarily.
1295 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1297 unsigned long flags
;
1299 local_irq_save(flags
);
1300 kmemcheck_slab_free(s
, x
, s
->object_size
);
1301 debug_check_no_locks_freed(x
, s
->object_size
);
1302 local_irq_restore(flags
);
1305 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
1306 debug_check_no_obj_freed(x
, s
->object_size
);
1308 kasan_slab_free(s
, x
);
1311 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1314 setup_object_debug(s
, page
, object
);
1315 if (unlikely(s
->ctor
)) {
1316 kasan_unpoison_object_data(s
, object
);
1318 kasan_poison_object_data(s
, object
);
1323 * Slab allocation and freeing
1325 static inline struct page
*alloc_slab_page(struct kmem_cache
*s
,
1326 gfp_t flags
, int node
, struct kmem_cache_order_objects oo
)
1329 int order
= oo_order(oo
);
1331 flags
|= __GFP_NOTRACK
;
1333 if (node
== NUMA_NO_NODE
)
1334 page
= alloc_pages(flags
, order
);
1336 page
= __alloc_pages_node(node
, flags
, order
);
1338 if (page
&& memcg_charge_slab(page
, flags
, order
, s
)) {
1339 __free_pages(page
, order
);
1346 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1349 struct kmem_cache_order_objects oo
= s
->oo
;
1354 flags
&= gfp_allowed_mask
;
1356 if (flags
& __GFP_WAIT
)
1359 flags
|= s
->allocflags
;
1362 * Let the initial higher-order allocation fail under memory pressure
1363 * so we fall-back to the minimum order allocation.
1365 alloc_gfp
= (flags
| __GFP_NOWARN
| __GFP_NORETRY
) & ~__GFP_NOFAIL
;
1366 if ((alloc_gfp
& __GFP_WAIT
) && oo_order(oo
) > oo_order(s
->min
))
1367 alloc_gfp
= (alloc_gfp
| __GFP_NOMEMALLOC
) & ~__GFP_WAIT
;
1369 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1370 if (unlikely(!page
)) {
1374 * Allocation may have failed due to fragmentation.
1375 * Try a lower order alloc if possible
1377 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1378 if (unlikely(!page
))
1380 stat(s
, ORDER_FALLBACK
);
1383 if (kmemcheck_enabled
&&
1384 !(s
->flags
& (SLAB_NOTRACK
| DEBUG_DEFAULT_FLAGS
))) {
1385 int pages
= 1 << oo_order(oo
);
1387 kmemcheck_alloc_shadow(page
, oo_order(oo
), alloc_gfp
, node
);
1390 * Objects from caches that have a constructor don't get
1391 * cleared when they're allocated, so we need to do it here.
1394 kmemcheck_mark_uninitialized_pages(page
, pages
);
1396 kmemcheck_mark_unallocated_pages(page
, pages
);
1399 page
->objects
= oo_objects(oo
);
1401 order
= compound_order(page
);
1402 page
->slab_cache
= s
;
1403 __SetPageSlab(page
);
1404 if (page_is_pfmemalloc(page
))
1405 SetPageSlabPfmemalloc(page
);
1407 start
= page_address(page
);
1409 if (unlikely(s
->flags
& SLAB_POISON
))
1410 memset(start
, POISON_INUSE
, PAGE_SIZE
<< order
);
1412 kasan_poison_slab(page
);
1414 for_each_object_idx(p
, idx
, s
, start
, page
->objects
) {
1415 setup_object(s
, page
, p
);
1416 if (likely(idx
< page
->objects
))
1417 set_freepointer(s
, p
, p
+ s
->size
);
1419 set_freepointer(s
, p
, NULL
);
1422 page
->freelist
= start
;
1423 page
->inuse
= page
->objects
;
1427 if (flags
& __GFP_WAIT
)
1428 local_irq_disable();
1432 mod_zone_page_state(page_zone(page
),
1433 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1434 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1437 inc_slabs_node(s
, page_to_nid(page
), page
->objects
);
1442 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1444 if (unlikely(flags
& GFP_SLAB_BUG_MASK
)) {
1445 pr_emerg("gfp: %u\n", flags
& GFP_SLAB_BUG_MASK
);
1449 return allocate_slab(s
,
1450 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1453 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1455 int order
= compound_order(page
);
1456 int pages
= 1 << order
;
1458 if (kmem_cache_debug(s
)) {
1461 slab_pad_check(s
, page
);
1462 for_each_object(p
, s
, page_address(page
),
1464 check_object(s
, page
, p
, SLUB_RED_INACTIVE
);
1467 kmemcheck_free_shadow(page
, compound_order(page
));
1469 mod_zone_page_state(page_zone(page
),
1470 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1471 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1474 __ClearPageSlabPfmemalloc(page
);
1475 __ClearPageSlab(page
);
1477 page_mapcount_reset(page
);
1478 if (current
->reclaim_state
)
1479 current
->reclaim_state
->reclaimed_slab
+= pages
;
1480 __free_kmem_pages(page
, order
);
1483 #define need_reserve_slab_rcu \
1484 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1486 static void rcu_free_slab(struct rcu_head
*h
)
1490 if (need_reserve_slab_rcu
)
1491 page
= virt_to_head_page(h
);
1493 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1495 __free_slab(page
->slab_cache
, page
);
1498 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1500 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1501 struct rcu_head
*head
;
1503 if (need_reserve_slab_rcu
) {
1504 int order
= compound_order(page
);
1505 int offset
= (PAGE_SIZE
<< order
) - s
->reserved
;
1507 VM_BUG_ON(s
->reserved
!= sizeof(*head
));
1508 head
= page_address(page
) + offset
;
1511 * RCU free overloads the RCU head over the LRU
1513 head
= (void *)&page
->lru
;
1516 call_rcu(head
, rcu_free_slab
);
1518 __free_slab(s
, page
);
1521 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1523 dec_slabs_node(s
, page_to_nid(page
), page
->objects
);
1528 * Management of partially allocated slabs.
1531 __add_partial(struct kmem_cache_node
*n
, struct page
*page
, int tail
)
1534 if (tail
== DEACTIVATE_TO_TAIL
)
1535 list_add_tail(&page
->lru
, &n
->partial
);
1537 list_add(&page
->lru
, &n
->partial
);
1540 static inline void add_partial(struct kmem_cache_node
*n
,
1541 struct page
*page
, int tail
)
1543 lockdep_assert_held(&n
->list_lock
);
1544 __add_partial(n
, page
, tail
);
1548 __remove_partial(struct kmem_cache_node
*n
, struct page
*page
)
1550 list_del(&page
->lru
);
1554 static inline void remove_partial(struct kmem_cache_node
*n
,
1557 lockdep_assert_held(&n
->list_lock
);
1558 __remove_partial(n
, page
);
1562 * Remove slab from the partial list, freeze it and
1563 * return the pointer to the freelist.
1565 * Returns a list of objects or NULL if it fails.
1567 static inline void *acquire_slab(struct kmem_cache
*s
,
1568 struct kmem_cache_node
*n
, struct page
*page
,
1569 int mode
, int *objects
)
1572 unsigned long counters
;
1575 lockdep_assert_held(&n
->list_lock
);
1578 * Zap the freelist and set the frozen bit.
1579 * The old freelist is the list of objects for the
1580 * per cpu allocation list.
1582 freelist
= page
->freelist
;
1583 counters
= page
->counters
;
1584 new.counters
= counters
;
1585 *objects
= new.objects
- new.inuse
;
1587 new.inuse
= page
->objects
;
1588 new.freelist
= NULL
;
1590 new.freelist
= freelist
;
1593 VM_BUG_ON(new.frozen
);
1596 if (!__cmpxchg_double_slab(s
, page
,
1598 new.freelist
, new.counters
,
1602 remove_partial(n
, page
);
1607 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
);
1608 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
);
1611 * Try to allocate a partial slab from a specific node.
1613 static void *get_partial_node(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1614 struct kmem_cache_cpu
*c
, gfp_t flags
)
1616 struct page
*page
, *page2
;
1617 void *object
= NULL
;
1622 * Racy check. If we mistakenly see no partial slabs then we
1623 * just allocate an empty slab. If we mistakenly try to get a
1624 * partial slab and there is none available then get_partials()
1627 if (!n
|| !n
->nr_partial
)
1630 spin_lock(&n
->list_lock
);
1631 list_for_each_entry_safe(page
, page2
, &n
->partial
, lru
) {
1634 if (!pfmemalloc_match(page
, flags
))
1637 t
= acquire_slab(s
, n
, page
, object
== NULL
, &objects
);
1641 available
+= objects
;
1644 stat(s
, ALLOC_FROM_PARTIAL
);
1647 put_cpu_partial(s
, page
, 0);
1648 stat(s
, CPU_PARTIAL_NODE
);
1650 if (!kmem_cache_has_cpu_partial(s
)
1651 || available
> s
->cpu_partial
/ 2)
1655 spin_unlock(&n
->list_lock
);
1660 * Get a page from somewhere. Search in increasing NUMA distances.
1662 static void *get_any_partial(struct kmem_cache
*s
, gfp_t flags
,
1663 struct kmem_cache_cpu
*c
)
1666 struct zonelist
*zonelist
;
1669 enum zone_type high_zoneidx
= gfp_zone(flags
);
1671 unsigned int cpuset_mems_cookie
;
1674 * The defrag ratio allows a configuration of the tradeoffs between
1675 * inter node defragmentation and node local allocations. A lower
1676 * defrag_ratio increases the tendency to do local allocations
1677 * instead of attempting to obtain partial slabs from other nodes.
1679 * If the defrag_ratio is set to 0 then kmalloc() always
1680 * returns node local objects. If the ratio is higher then kmalloc()
1681 * may return off node objects because partial slabs are obtained
1682 * from other nodes and filled up.
1684 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1685 * defrag_ratio = 1000) then every (well almost) allocation will
1686 * first attempt to defrag slab caches on other nodes. This means
1687 * scanning over all nodes to look for partial slabs which may be
1688 * expensive if we do it every time we are trying to find a slab
1689 * with available objects.
1691 if (!s
->remote_node_defrag_ratio
||
1692 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1696 cpuset_mems_cookie
= read_mems_allowed_begin();
1697 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
1698 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
1699 struct kmem_cache_node
*n
;
1701 n
= get_node(s
, zone_to_nid(zone
));
1703 if (n
&& cpuset_zone_allowed(zone
, flags
) &&
1704 n
->nr_partial
> s
->min_partial
) {
1705 object
= get_partial_node(s
, n
, c
, flags
);
1708 * Don't check read_mems_allowed_retry()
1709 * here - if mems_allowed was updated in
1710 * parallel, that was a harmless race
1711 * between allocation and the cpuset
1718 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1724 * Get a partial page, lock it and return it.
1726 static void *get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
,
1727 struct kmem_cache_cpu
*c
)
1730 int searchnode
= node
;
1732 if (node
== NUMA_NO_NODE
)
1733 searchnode
= numa_mem_id();
1734 else if (!node_present_pages(node
))
1735 searchnode
= node_to_mem_node(node
);
1737 object
= get_partial_node(s
, get_node(s
, searchnode
), c
, flags
);
1738 if (object
|| node
!= NUMA_NO_NODE
)
1741 return get_any_partial(s
, flags
, c
);
1744 #ifdef CONFIG_PREEMPT
1746 * Calculate the next globally unique transaction for disambiguiation
1747 * during cmpxchg. The transactions start with the cpu number and are then
1748 * incremented by CONFIG_NR_CPUS.
1750 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1753 * No preemption supported therefore also no need to check for
1759 static inline unsigned long next_tid(unsigned long tid
)
1761 return tid
+ TID_STEP
;
1764 static inline unsigned int tid_to_cpu(unsigned long tid
)
1766 return tid
% TID_STEP
;
1769 static inline unsigned long tid_to_event(unsigned long tid
)
1771 return tid
/ TID_STEP
;
1774 static inline unsigned int init_tid(int cpu
)
1779 static inline void note_cmpxchg_failure(const char *n
,
1780 const struct kmem_cache
*s
, unsigned long tid
)
1782 #ifdef SLUB_DEBUG_CMPXCHG
1783 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
1785 pr_info("%s %s: cmpxchg redo ", n
, s
->name
);
1787 #ifdef CONFIG_PREEMPT
1788 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
1789 pr_warn("due to cpu change %d -> %d\n",
1790 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
1793 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
1794 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1795 tid_to_event(tid
), tid_to_event(actual_tid
));
1797 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1798 actual_tid
, tid
, next_tid(tid
));
1800 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
1803 static void init_kmem_cache_cpus(struct kmem_cache
*s
)
1807 for_each_possible_cpu(cpu
)
1808 per_cpu_ptr(s
->cpu_slab
, cpu
)->tid
= init_tid(cpu
);
1812 * Remove the cpu slab
1814 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
,
1817 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
1818 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1820 enum slab_modes l
= M_NONE
, m
= M_NONE
;
1822 int tail
= DEACTIVATE_TO_HEAD
;
1826 if (page
->freelist
) {
1827 stat(s
, DEACTIVATE_REMOTE_FREES
);
1828 tail
= DEACTIVATE_TO_TAIL
;
1832 * Stage one: Free all available per cpu objects back
1833 * to the page freelist while it is still frozen. Leave the
1836 * There is no need to take the list->lock because the page
1839 while (freelist
&& (nextfree
= get_freepointer(s
, freelist
))) {
1841 unsigned long counters
;
1844 prior
= page
->freelist
;
1845 counters
= page
->counters
;
1846 set_freepointer(s
, freelist
, prior
);
1847 new.counters
= counters
;
1849 VM_BUG_ON(!new.frozen
);
1851 } while (!__cmpxchg_double_slab(s
, page
,
1853 freelist
, new.counters
,
1854 "drain percpu freelist"));
1856 freelist
= nextfree
;
1860 * Stage two: Ensure that the page is unfrozen while the
1861 * list presence reflects the actual number of objects
1864 * We setup the list membership and then perform a cmpxchg
1865 * with the count. If there is a mismatch then the page
1866 * is not unfrozen but the page is on the wrong list.
1868 * Then we restart the process which may have to remove
1869 * the page from the list that we just put it on again
1870 * because the number of objects in the slab may have
1875 old
.freelist
= page
->freelist
;
1876 old
.counters
= page
->counters
;
1877 VM_BUG_ON(!old
.frozen
);
1879 /* Determine target state of the slab */
1880 new.counters
= old
.counters
;
1883 set_freepointer(s
, freelist
, old
.freelist
);
1884 new.freelist
= freelist
;
1886 new.freelist
= old
.freelist
;
1890 if (!new.inuse
&& n
->nr_partial
>= s
->min_partial
)
1892 else if (new.freelist
) {
1897 * Taking the spinlock removes the possiblity
1898 * that acquire_slab() will see a slab page that
1901 spin_lock(&n
->list_lock
);
1905 if (kmem_cache_debug(s
) && !lock
) {
1908 * This also ensures that the scanning of full
1909 * slabs from diagnostic functions will not see
1912 spin_lock(&n
->list_lock
);
1920 remove_partial(n
, page
);
1922 else if (l
== M_FULL
)
1924 remove_full(s
, n
, page
);
1926 if (m
== M_PARTIAL
) {
1928 add_partial(n
, page
, tail
);
1931 } else if (m
== M_FULL
) {
1933 stat(s
, DEACTIVATE_FULL
);
1934 add_full(s
, n
, page
);
1940 if (!__cmpxchg_double_slab(s
, page
,
1941 old
.freelist
, old
.counters
,
1942 new.freelist
, new.counters
,
1947 spin_unlock(&n
->list_lock
);
1950 stat(s
, DEACTIVATE_EMPTY
);
1951 discard_slab(s
, page
);
1957 * Unfreeze all the cpu partial slabs.
1959 * This function must be called with interrupts disabled
1960 * for the cpu using c (or some other guarantee must be there
1961 * to guarantee no concurrent accesses).
1963 static void unfreeze_partials(struct kmem_cache
*s
,
1964 struct kmem_cache_cpu
*c
)
1966 #ifdef CONFIG_SLUB_CPU_PARTIAL
1967 struct kmem_cache_node
*n
= NULL
, *n2
= NULL
;
1968 struct page
*page
, *discard_page
= NULL
;
1970 while ((page
= c
->partial
)) {
1974 c
->partial
= page
->next
;
1976 n2
= get_node(s
, page_to_nid(page
));
1979 spin_unlock(&n
->list_lock
);
1982 spin_lock(&n
->list_lock
);
1987 old
.freelist
= page
->freelist
;
1988 old
.counters
= page
->counters
;
1989 VM_BUG_ON(!old
.frozen
);
1991 new.counters
= old
.counters
;
1992 new.freelist
= old
.freelist
;
1996 } while (!__cmpxchg_double_slab(s
, page
,
1997 old
.freelist
, old
.counters
,
1998 new.freelist
, new.counters
,
1999 "unfreezing slab"));
2001 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
)) {
2002 page
->next
= discard_page
;
2003 discard_page
= page
;
2005 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2006 stat(s
, FREE_ADD_PARTIAL
);
2011 spin_unlock(&n
->list_lock
);
2013 while (discard_page
) {
2014 page
= discard_page
;
2015 discard_page
= discard_page
->next
;
2017 stat(s
, DEACTIVATE_EMPTY
);
2018 discard_slab(s
, page
);
2025 * Put a page that was just frozen (in __slab_free) into a partial page
2026 * slot if available. This is done without interrupts disabled and without
2027 * preemption disabled. The cmpxchg is racy and may put the partial page
2028 * onto a random cpus partial slot.
2030 * If we did not find a slot then simply move all the partials to the
2031 * per node partial list.
2033 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
)
2035 #ifdef CONFIG_SLUB_CPU_PARTIAL
2036 struct page
*oldpage
;
2044 oldpage
= this_cpu_read(s
->cpu_slab
->partial
);
2047 pobjects
= oldpage
->pobjects
;
2048 pages
= oldpage
->pages
;
2049 if (drain
&& pobjects
> s
->cpu_partial
) {
2050 unsigned long flags
;
2052 * partial array is full. Move the existing
2053 * set to the per node partial list.
2055 local_irq_save(flags
);
2056 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2057 local_irq_restore(flags
);
2061 stat(s
, CPU_PARTIAL_DRAIN
);
2066 pobjects
+= page
->objects
- page
->inuse
;
2068 page
->pages
= pages
;
2069 page
->pobjects
= pobjects
;
2070 page
->next
= oldpage
;
2072 } while (this_cpu_cmpxchg(s
->cpu_slab
->partial
, oldpage
, page
)
2074 if (unlikely(!s
->cpu_partial
)) {
2075 unsigned long flags
;
2077 local_irq_save(flags
);
2078 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2079 local_irq_restore(flags
);
2085 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
2087 stat(s
, CPUSLAB_FLUSH
);
2088 deactivate_slab(s
, c
->page
, c
->freelist
);
2090 c
->tid
= next_tid(c
->tid
);
2098 * Called from IPI handler with interrupts disabled.
2100 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
2102 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2108 unfreeze_partials(s
, c
);
2112 static void flush_cpu_slab(void *d
)
2114 struct kmem_cache
*s
= d
;
2116 __flush_cpu_slab(s
, smp_processor_id());
2119 static bool has_cpu_slab(int cpu
, void *info
)
2121 struct kmem_cache
*s
= info
;
2122 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2124 return c
->page
|| c
->partial
;
2127 static void flush_all(struct kmem_cache
*s
)
2129 on_each_cpu_cond(has_cpu_slab
, flush_cpu_slab
, s
, 1, GFP_ATOMIC
);
2133 * Check if the objects in a per cpu structure fit numa
2134 * locality expectations.
2136 static inline int node_match(struct page
*page
, int node
)
2139 if (!page
|| (node
!= NUMA_NO_NODE
&& page_to_nid(page
) != node
))
2145 #ifdef CONFIG_SLUB_DEBUG
2146 static int count_free(struct page
*page
)
2148 return page
->objects
- page
->inuse
;
2151 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
2153 return atomic_long_read(&n
->total_objects
);
2155 #endif /* CONFIG_SLUB_DEBUG */
2157 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2158 static unsigned long count_partial(struct kmem_cache_node
*n
,
2159 int (*get_count
)(struct page
*))
2161 unsigned long flags
;
2162 unsigned long x
= 0;
2165 spin_lock_irqsave(&n
->list_lock
, flags
);
2166 list_for_each_entry(page
, &n
->partial
, lru
)
2167 x
+= get_count(page
);
2168 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2171 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2173 static noinline
void
2174 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
2176 #ifdef CONFIG_SLUB_DEBUG
2177 static DEFINE_RATELIMIT_STATE(slub_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2178 DEFAULT_RATELIMIT_BURST
);
2180 struct kmem_cache_node
*n
;
2182 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slub_oom_rs
))
2185 pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2187 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2188 s
->name
, s
->object_size
, s
->size
, oo_order(s
->oo
),
2191 if (oo_order(s
->min
) > get_order(s
->object_size
))
2192 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2195 for_each_kmem_cache_node(s
, node
, n
) {
2196 unsigned long nr_slabs
;
2197 unsigned long nr_objs
;
2198 unsigned long nr_free
;
2200 nr_free
= count_partial(n
, count_free
);
2201 nr_slabs
= node_nr_slabs(n
);
2202 nr_objs
= node_nr_objs(n
);
2204 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2205 node
, nr_slabs
, nr_objs
, nr_free
);
2210 static inline void *new_slab_objects(struct kmem_cache
*s
, gfp_t flags
,
2211 int node
, struct kmem_cache_cpu
**pc
)
2214 struct kmem_cache_cpu
*c
= *pc
;
2217 freelist
= get_partial(s
, flags
, node
, c
);
2222 page
= new_slab(s
, flags
, node
);
2224 c
= raw_cpu_ptr(s
->cpu_slab
);
2229 * No other reference to the page yet so we can
2230 * muck around with it freely without cmpxchg
2232 freelist
= page
->freelist
;
2233 page
->freelist
= NULL
;
2235 stat(s
, ALLOC_SLAB
);
2244 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
)
2246 if (unlikely(PageSlabPfmemalloc(page
)))
2247 return gfp_pfmemalloc_allowed(gfpflags
);
2253 * Check the page->freelist of a page and either transfer the freelist to the
2254 * per cpu freelist or deactivate the page.
2256 * The page is still frozen if the return value is not NULL.
2258 * If this function returns NULL then the page has been unfrozen.
2260 * This function must be called with interrupt disabled.
2262 static inline void *get_freelist(struct kmem_cache
*s
, struct page
*page
)
2265 unsigned long counters
;
2269 freelist
= page
->freelist
;
2270 counters
= page
->counters
;
2272 new.counters
= counters
;
2273 VM_BUG_ON(!new.frozen
);
2275 new.inuse
= page
->objects
;
2276 new.frozen
= freelist
!= NULL
;
2278 } while (!__cmpxchg_double_slab(s
, page
,
2287 * Slow path. The lockless freelist is empty or we need to perform
2290 * Processing is still very fast if new objects have been freed to the
2291 * regular freelist. In that case we simply take over the regular freelist
2292 * as the lockless freelist and zap the regular freelist.
2294 * If that is not working then we fall back to the partial lists. We take the
2295 * first element of the freelist as the object to allocate now and move the
2296 * rest of the freelist to the lockless freelist.
2298 * And if we were unable to get a new slab from the partial slab lists then
2299 * we need to allocate a new slab. This is the slowest path since it involves
2300 * a call to the page allocator and the setup of a new slab.
2302 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2303 unsigned long addr
, struct kmem_cache_cpu
*c
)
2307 unsigned long flags
;
2309 local_irq_save(flags
);
2310 #ifdef CONFIG_PREEMPT
2312 * We may have been preempted and rescheduled on a different
2313 * cpu before disabling interrupts. Need to reload cpu area
2316 c
= this_cpu_ptr(s
->cpu_slab
);
2324 if (unlikely(!node_match(page
, node
))) {
2325 int searchnode
= node
;
2327 if (node
!= NUMA_NO_NODE
&& !node_present_pages(node
))
2328 searchnode
= node_to_mem_node(node
);
2330 if (unlikely(!node_match(page
, searchnode
))) {
2331 stat(s
, ALLOC_NODE_MISMATCH
);
2332 deactivate_slab(s
, page
, c
->freelist
);
2340 * By rights, we should be searching for a slab page that was
2341 * PFMEMALLOC but right now, we are losing the pfmemalloc
2342 * information when the page leaves the per-cpu allocator
2344 if (unlikely(!pfmemalloc_match(page
, gfpflags
))) {
2345 deactivate_slab(s
, page
, c
->freelist
);
2351 /* must check again c->freelist in case of cpu migration or IRQ */
2352 freelist
= c
->freelist
;
2356 freelist
= get_freelist(s
, page
);
2360 stat(s
, DEACTIVATE_BYPASS
);
2364 stat(s
, ALLOC_REFILL
);
2368 * freelist is pointing to the list of objects to be used.
2369 * page is pointing to the page from which the objects are obtained.
2370 * That page must be frozen for per cpu allocations to work.
2372 VM_BUG_ON(!c
->page
->frozen
);
2373 c
->freelist
= get_freepointer(s
, freelist
);
2374 c
->tid
= next_tid(c
->tid
);
2375 local_irq_restore(flags
);
2381 page
= c
->page
= c
->partial
;
2382 c
->partial
= page
->next
;
2383 stat(s
, CPU_PARTIAL_ALLOC
);
2388 freelist
= new_slab_objects(s
, gfpflags
, node
, &c
);
2390 if (unlikely(!freelist
)) {
2391 slab_out_of_memory(s
, gfpflags
, node
);
2392 local_irq_restore(flags
);
2397 if (likely(!kmem_cache_debug(s
) && pfmemalloc_match(page
, gfpflags
)))
2400 /* Only entered in the debug case */
2401 if (kmem_cache_debug(s
) &&
2402 !alloc_debug_processing(s
, page
, freelist
, addr
))
2403 goto new_slab
; /* Slab failed checks. Next slab needed */
2405 deactivate_slab(s
, page
, get_freepointer(s
, freelist
));
2408 local_irq_restore(flags
);
2413 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2414 * have the fastpath folded into their functions. So no function call
2415 * overhead for requests that can be satisfied on the fastpath.
2417 * The fastpath works by first checking if the lockless freelist can be used.
2418 * If not then __slab_alloc is called for slow processing.
2420 * Otherwise we can simply pick the next object from the lockless free list.
2422 static __always_inline
void *slab_alloc_node(struct kmem_cache
*s
,
2423 gfp_t gfpflags
, int node
, unsigned long addr
)
2426 struct kmem_cache_cpu
*c
;
2430 s
= slab_pre_alloc_hook(s
, gfpflags
);
2435 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2436 * enabled. We may switch back and forth between cpus while
2437 * reading from one cpu area. That does not matter as long
2438 * as we end up on the original cpu again when doing the cmpxchg.
2440 * We should guarantee that tid and kmem_cache are retrieved on
2441 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2442 * to check if it is matched or not.
2445 tid
= this_cpu_read(s
->cpu_slab
->tid
);
2446 c
= raw_cpu_ptr(s
->cpu_slab
);
2447 } while (IS_ENABLED(CONFIG_PREEMPT
) &&
2448 unlikely(tid
!= READ_ONCE(c
->tid
)));
2451 * Irqless object alloc/free algorithm used here depends on sequence
2452 * of fetching cpu_slab's data. tid should be fetched before anything
2453 * on c to guarantee that object and page associated with previous tid
2454 * won't be used with current tid. If we fetch tid first, object and
2455 * page could be one associated with next tid and our alloc/free
2456 * request will be failed. In this case, we will retry. So, no problem.
2461 * The transaction ids are globally unique per cpu and per operation on
2462 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2463 * occurs on the right processor and that there was no operation on the
2464 * linked list in between.
2467 object
= c
->freelist
;
2469 if (unlikely(!object
|| !node_match(page
, node
))) {
2470 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
2471 stat(s
, ALLOC_SLOWPATH
);
2473 void *next_object
= get_freepointer_safe(s
, object
);
2476 * The cmpxchg will only match if there was no additional
2477 * operation and if we are on the right processor.
2479 * The cmpxchg does the following atomically (without lock
2481 * 1. Relocate first pointer to the current per cpu area.
2482 * 2. Verify that tid and freelist have not been changed
2483 * 3. If they were not changed replace tid and freelist
2485 * Since this is without lock semantics the protection is only
2486 * against code executing on this cpu *not* from access by
2489 if (unlikely(!this_cpu_cmpxchg_double(
2490 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2492 next_object
, next_tid(tid
)))) {
2494 note_cmpxchg_failure("slab_alloc", s
, tid
);
2497 prefetch_freepointer(s
, next_object
);
2498 stat(s
, ALLOC_FASTPATH
);
2501 if (unlikely(gfpflags
& __GFP_ZERO
) && object
)
2502 memset(object
, 0, s
->object_size
);
2504 slab_post_alloc_hook(s
, gfpflags
, object
);
2509 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
2510 gfp_t gfpflags
, unsigned long addr
)
2512 return slab_alloc_node(s
, gfpflags
, NUMA_NO_NODE
, addr
);
2515 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
2517 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2519 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->object_size
,
2524 EXPORT_SYMBOL(kmem_cache_alloc
);
2526 #ifdef CONFIG_TRACING
2527 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
2529 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2530 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
2531 kasan_kmalloc(s
, ret
, size
);
2534 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
2538 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
2540 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2542 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
2543 s
->object_size
, s
->size
, gfpflags
, node
);
2547 EXPORT_SYMBOL(kmem_cache_alloc_node
);
2549 #ifdef CONFIG_TRACING
2550 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
2552 int node
, size_t size
)
2554 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2556 trace_kmalloc_node(_RET_IP_
, ret
,
2557 size
, s
->size
, gfpflags
, node
);
2559 kasan_kmalloc(s
, ret
, size
);
2562 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
2567 * Slow path handling. This may still be called frequently since objects
2568 * have a longer lifetime than the cpu slabs in most processing loads.
2570 * So we still attempt to reduce cache line usage. Just take the slab
2571 * lock and free the item. If there is no additional partial page
2572 * handling required then we can return immediately.
2574 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
2575 void *x
, unsigned long addr
)
2578 void **object
= (void *)x
;
2581 unsigned long counters
;
2582 struct kmem_cache_node
*n
= NULL
;
2583 unsigned long uninitialized_var(flags
);
2585 stat(s
, FREE_SLOWPATH
);
2587 if (kmem_cache_debug(s
) &&
2588 !(n
= free_debug_processing(s
, page
, x
, addr
, &flags
)))
2593 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2596 prior
= page
->freelist
;
2597 counters
= page
->counters
;
2598 set_freepointer(s
, object
, prior
);
2599 new.counters
= counters
;
2600 was_frozen
= new.frozen
;
2602 if ((!new.inuse
|| !prior
) && !was_frozen
) {
2604 if (kmem_cache_has_cpu_partial(s
) && !prior
) {
2607 * Slab was on no list before and will be
2609 * We can defer the list move and instead
2614 } else { /* Needs to be taken off a list */
2616 n
= get_node(s
, page_to_nid(page
));
2618 * Speculatively acquire the list_lock.
2619 * If the cmpxchg does not succeed then we may
2620 * drop the list_lock without any processing.
2622 * Otherwise the list_lock will synchronize with
2623 * other processors updating the list of slabs.
2625 spin_lock_irqsave(&n
->list_lock
, flags
);
2630 } while (!cmpxchg_double_slab(s
, page
,
2632 object
, new.counters
,
2638 * If we just froze the page then put it onto the
2639 * per cpu partial list.
2641 if (new.frozen
&& !was_frozen
) {
2642 put_cpu_partial(s
, page
, 1);
2643 stat(s
, CPU_PARTIAL_FREE
);
2646 * The list lock was not taken therefore no list
2647 * activity can be necessary.
2650 stat(s
, FREE_FROZEN
);
2654 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
))
2658 * Objects left in the slab. If it was not on the partial list before
2661 if (!kmem_cache_has_cpu_partial(s
) && unlikely(!prior
)) {
2662 if (kmem_cache_debug(s
))
2663 remove_full(s
, n
, page
);
2664 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2665 stat(s
, FREE_ADD_PARTIAL
);
2667 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2673 * Slab on the partial list.
2675 remove_partial(n
, page
);
2676 stat(s
, FREE_REMOVE_PARTIAL
);
2678 /* Slab must be on the full list */
2679 remove_full(s
, n
, page
);
2682 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2684 discard_slab(s
, page
);
2688 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2689 * can perform fastpath freeing without additional function calls.
2691 * The fastpath is only possible if we are freeing to the current cpu slab
2692 * of this processor. This typically the case if we have just allocated
2695 * If fastpath is not possible then fall back to __slab_free where we deal
2696 * with all sorts of special processing.
2698 static __always_inline
void slab_free(struct kmem_cache
*s
,
2699 struct page
*page
, void *x
, unsigned long addr
)
2701 void **object
= (void *)x
;
2702 struct kmem_cache_cpu
*c
;
2705 slab_free_hook(s
, x
);
2709 * Determine the currently cpus per cpu slab.
2710 * The cpu may change afterward. However that does not matter since
2711 * data is retrieved via this pointer. If we are on the same cpu
2712 * during the cmpxchg then the free will succeed.
2715 tid
= this_cpu_read(s
->cpu_slab
->tid
);
2716 c
= raw_cpu_ptr(s
->cpu_slab
);
2717 } while (IS_ENABLED(CONFIG_PREEMPT
) &&
2718 unlikely(tid
!= READ_ONCE(c
->tid
)));
2720 /* Same with comment on barrier() in slab_alloc_node() */
2723 if (likely(page
== c
->page
)) {
2724 set_freepointer(s
, object
, c
->freelist
);
2726 if (unlikely(!this_cpu_cmpxchg_double(
2727 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2729 object
, next_tid(tid
)))) {
2731 note_cmpxchg_failure("slab_free", s
, tid
);
2734 stat(s
, FREE_FASTPATH
);
2736 __slab_free(s
, page
, x
, addr
);
2740 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
2742 s
= cache_from_obj(s
, x
);
2745 slab_free(s
, virt_to_head_page(x
), x
, _RET_IP_
);
2746 trace_kmem_cache_free(_RET_IP_
, x
);
2748 EXPORT_SYMBOL(kmem_cache_free
);
2750 /* Note that interrupts must be enabled when calling this function. */
2751 void kmem_cache_free_bulk(struct kmem_cache
*s
, size_t size
, void **p
)
2753 struct kmem_cache_cpu
*c
;
2757 local_irq_disable();
2758 c
= this_cpu_ptr(s
->cpu_slab
);
2760 for (i
= 0; i
< size
; i
++) {
2761 void *object
= p
[i
];
2764 /* kmem cache debug support */
2765 s
= cache_from_obj(s
, object
);
2768 slab_free_hook(s
, object
);
2770 page
= virt_to_head_page(object
);
2772 if (c
->page
== page
) {
2773 /* Fastpath: local CPU free */
2774 set_freepointer(s
, object
, c
->freelist
);
2775 c
->freelist
= object
;
2777 c
->tid
= next_tid(c
->tid
);
2779 /* Slowpath: overhead locked cmpxchg_double_slab */
2780 __slab_free(s
, page
, object
, _RET_IP_
);
2781 local_irq_disable();
2782 c
= this_cpu_ptr(s
->cpu_slab
);
2786 c
->tid
= next_tid(c
->tid
);
2789 EXPORT_SYMBOL(kmem_cache_free_bulk
);
2791 /* Note that interrupts must be enabled when calling this function. */
2792 bool kmem_cache_alloc_bulk(struct kmem_cache
*s
, gfp_t flags
, size_t size
,
2795 struct kmem_cache_cpu
*c
;
2799 * Drain objects in the per cpu slab, while disabling local
2800 * IRQs, which protects against PREEMPT and interrupts
2801 * handlers invoking normal fastpath.
2803 local_irq_disable();
2804 c
= this_cpu_ptr(s
->cpu_slab
);
2806 for (i
= 0; i
< size
; i
++) {
2807 void *object
= c
->freelist
;
2809 if (unlikely(!object
)) {
2812 * Invoking slow path likely have side-effect
2813 * of re-populating per CPU c->freelist
2815 p
[i
] = __slab_alloc(s
, flags
, NUMA_NO_NODE
,
2817 if (unlikely(!p
[i
])) {
2818 __kmem_cache_free_bulk(s
, i
, p
);
2821 local_irq_disable();
2822 c
= this_cpu_ptr(s
->cpu_slab
);
2823 continue; /* goto for-loop */
2826 /* kmem_cache debug support */
2827 s
= slab_pre_alloc_hook(s
, flags
);
2829 __kmem_cache_free_bulk(s
, i
, p
);
2830 c
->tid
= next_tid(c
->tid
);
2835 c
->freelist
= get_freepointer(s
, object
);
2838 /* kmem_cache debug support */
2839 slab_post_alloc_hook(s
, flags
, object
);
2841 c
->tid
= next_tid(c
->tid
);
2844 /* Clear memory outside IRQ disabled fastpath loop */
2845 if (unlikely(flags
& __GFP_ZERO
)) {
2848 for (j
= 0; j
< i
; j
++)
2849 memset(p
[j
], 0, s
->object_size
);
2854 EXPORT_SYMBOL(kmem_cache_alloc_bulk
);
2858 * Object placement in a slab is made very easy because we always start at
2859 * offset 0. If we tune the size of the object to the alignment then we can
2860 * get the required alignment by putting one properly sized object after
2863 * Notice that the allocation order determines the sizes of the per cpu
2864 * caches. Each processor has always one slab available for allocations.
2865 * Increasing the allocation order reduces the number of times that slabs
2866 * must be moved on and off the partial lists and is therefore a factor in
2871 * Mininum / Maximum order of slab pages. This influences locking overhead
2872 * and slab fragmentation. A higher order reduces the number of partial slabs
2873 * and increases the number of allocations possible without having to
2874 * take the list_lock.
2876 static int slub_min_order
;
2877 static int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
2878 static int slub_min_objects
;
2881 * Calculate the order of allocation given an slab object size.
2883 * The order of allocation has significant impact on performance and other
2884 * system components. Generally order 0 allocations should be preferred since
2885 * order 0 does not cause fragmentation in the page allocator. Larger objects
2886 * be problematic to put into order 0 slabs because there may be too much
2887 * unused space left. We go to a higher order if more than 1/16th of the slab
2890 * In order to reach satisfactory performance we must ensure that a minimum
2891 * number of objects is in one slab. Otherwise we may generate too much
2892 * activity on the partial lists which requires taking the list_lock. This is
2893 * less a concern for large slabs though which are rarely used.
2895 * slub_max_order specifies the order where we begin to stop considering the
2896 * number of objects in a slab as critical. If we reach slub_max_order then
2897 * we try to keep the page order as low as possible. So we accept more waste
2898 * of space in favor of a small page order.
2900 * Higher order allocations also allow the placement of more objects in a
2901 * slab and thereby reduce object handling overhead. If the user has
2902 * requested a higher mininum order then we start with that one instead of
2903 * the smallest order which will fit the object.
2905 static inline int slab_order(int size
, int min_objects
,
2906 int max_order
, int fract_leftover
, int reserved
)
2910 int min_order
= slub_min_order
;
2912 if (order_objects(min_order
, size
, reserved
) > MAX_OBJS_PER_PAGE
)
2913 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
2915 for (order
= max(min_order
, get_order(min_objects
* size
+ reserved
));
2916 order
<= max_order
; order
++) {
2918 unsigned long slab_size
= PAGE_SIZE
<< order
;
2920 rem
= (slab_size
- reserved
) % size
;
2922 if (rem
<= slab_size
/ fract_leftover
)
2929 static inline int calculate_order(int size
, int reserved
)
2937 * Attempt to find best configuration for a slab. This
2938 * works by first attempting to generate a layout with
2939 * the best configuration and backing off gradually.
2941 * First we increase the acceptable waste in a slab. Then
2942 * we reduce the minimum objects required in a slab.
2944 min_objects
= slub_min_objects
;
2946 min_objects
= 4 * (fls(nr_cpu_ids
) + 1);
2947 max_objects
= order_objects(slub_max_order
, size
, reserved
);
2948 min_objects
= min(min_objects
, max_objects
);
2950 while (min_objects
> 1) {
2952 while (fraction
>= 4) {
2953 order
= slab_order(size
, min_objects
,
2954 slub_max_order
, fraction
, reserved
);
2955 if (order
<= slub_max_order
)
2963 * We were unable to place multiple objects in a slab. Now
2964 * lets see if we can place a single object there.
2966 order
= slab_order(size
, 1, slub_max_order
, 1, reserved
);
2967 if (order
<= slub_max_order
)
2971 * Doh this slab cannot be placed using slub_max_order.
2973 order
= slab_order(size
, 1, MAX_ORDER
, 1, reserved
);
2974 if (order
< MAX_ORDER
)
2980 init_kmem_cache_node(struct kmem_cache_node
*n
)
2983 spin_lock_init(&n
->list_lock
);
2984 INIT_LIST_HEAD(&n
->partial
);
2985 #ifdef CONFIG_SLUB_DEBUG
2986 atomic_long_set(&n
->nr_slabs
, 0);
2987 atomic_long_set(&n
->total_objects
, 0);
2988 INIT_LIST_HEAD(&n
->full
);
2992 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
2994 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
2995 KMALLOC_SHIFT_HIGH
* sizeof(struct kmem_cache_cpu
));
2998 * Must align to double word boundary for the double cmpxchg
2999 * instructions to work; see __pcpu_double_call_return_bool().
3001 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
3002 2 * sizeof(void *));
3007 init_kmem_cache_cpus(s
);
3012 static struct kmem_cache
*kmem_cache_node
;
3015 * No kmalloc_node yet so do it by hand. We know that this is the first
3016 * slab on the node for this slabcache. There are no concurrent accesses
3019 * Note that this function only works on the kmem_cache_node
3020 * when allocating for the kmem_cache_node. This is used for bootstrapping
3021 * memory on a fresh node that has no slab structures yet.
3023 static void early_kmem_cache_node_alloc(int node
)
3026 struct kmem_cache_node
*n
;
3028 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
3030 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
3033 if (page_to_nid(page
) != node
) {
3034 pr_err("SLUB: Unable to allocate memory from node %d\n", node
);
3035 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3040 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
3043 kmem_cache_node
->node
[node
] = n
;
3044 #ifdef CONFIG_SLUB_DEBUG
3045 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
3046 init_tracking(kmem_cache_node
, n
);
3048 kasan_kmalloc(kmem_cache_node
, n
, sizeof(struct kmem_cache_node
));
3049 init_kmem_cache_node(n
);
3050 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
3053 * No locks need to be taken here as it has just been
3054 * initialized and there is no concurrent access.
3056 __add_partial(n
, page
, DEACTIVATE_TO_HEAD
);
3059 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
3062 struct kmem_cache_node
*n
;
3064 for_each_kmem_cache_node(s
, node
, n
) {
3065 kmem_cache_free(kmem_cache_node
, n
);
3066 s
->node
[node
] = NULL
;
3070 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
3074 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3075 struct kmem_cache_node
*n
;
3077 if (slab_state
== DOWN
) {
3078 early_kmem_cache_node_alloc(node
);
3081 n
= kmem_cache_alloc_node(kmem_cache_node
,
3085 free_kmem_cache_nodes(s
);
3090 init_kmem_cache_node(n
);
3095 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
3097 if (min
< MIN_PARTIAL
)
3099 else if (min
> MAX_PARTIAL
)
3101 s
->min_partial
= min
;
3105 * calculate_sizes() determines the order and the distribution of data within
3108 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
3110 unsigned long flags
= s
->flags
;
3111 unsigned long size
= s
->object_size
;
3115 * Round up object size to the next word boundary. We can only
3116 * place the free pointer at word boundaries and this determines
3117 * the possible location of the free pointer.
3119 size
= ALIGN(size
, sizeof(void *));
3121 #ifdef CONFIG_SLUB_DEBUG
3123 * Determine if we can poison the object itself. If the user of
3124 * the slab may touch the object after free or before allocation
3125 * then we should never poison the object itself.
3127 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
3129 s
->flags
|= __OBJECT_POISON
;
3131 s
->flags
&= ~__OBJECT_POISON
;
3135 * If we are Redzoning then check if there is some space between the
3136 * end of the object and the free pointer. If not then add an
3137 * additional word to have some bytes to store Redzone information.
3139 if ((flags
& SLAB_RED_ZONE
) && size
== s
->object_size
)
3140 size
+= sizeof(void *);
3144 * With that we have determined the number of bytes in actual use
3145 * by the object. This is the potential offset to the free pointer.
3149 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
3152 * Relocate free pointer after the object if it is not
3153 * permitted to overwrite the first word of the object on
3156 * This is the case if we do RCU, have a constructor or
3157 * destructor or are poisoning the objects.
3160 size
+= sizeof(void *);
3163 #ifdef CONFIG_SLUB_DEBUG
3164 if (flags
& SLAB_STORE_USER
)
3166 * Need to store information about allocs and frees after
3169 size
+= 2 * sizeof(struct track
);
3171 if (flags
& SLAB_RED_ZONE
)
3173 * Add some empty padding so that we can catch
3174 * overwrites from earlier objects rather than let
3175 * tracking information or the free pointer be
3176 * corrupted if a user writes before the start
3179 size
+= sizeof(void *);
3183 * SLUB stores one object immediately after another beginning from
3184 * offset 0. In order to align the objects we have to simply size
3185 * each object to conform to the alignment.
3187 size
= ALIGN(size
, s
->align
);
3189 if (forced_order
>= 0)
3190 order
= forced_order
;
3192 order
= calculate_order(size
, s
->reserved
);
3199 s
->allocflags
|= __GFP_COMP
;
3201 if (s
->flags
& SLAB_CACHE_DMA
)
3202 s
->allocflags
|= GFP_DMA
;
3204 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3205 s
->allocflags
|= __GFP_RECLAIMABLE
;
3208 * Determine the number of objects per slab
3210 s
->oo
= oo_make(order
, size
, s
->reserved
);
3211 s
->min
= oo_make(get_order(size
), size
, s
->reserved
);
3212 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
3215 return !!oo_objects(s
->oo
);
3218 static int kmem_cache_open(struct kmem_cache
*s
, unsigned long flags
)
3220 s
->flags
= kmem_cache_flags(s
->size
, flags
, s
->name
, s
->ctor
);
3223 if (need_reserve_slab_rcu
&& (s
->flags
& SLAB_DESTROY_BY_RCU
))
3224 s
->reserved
= sizeof(struct rcu_head
);
3226 if (!calculate_sizes(s
, -1))
3228 if (disable_higher_order_debug
) {
3230 * Disable debugging flags that store metadata if the min slab
3233 if (get_order(s
->size
) > get_order(s
->object_size
)) {
3234 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
3236 if (!calculate_sizes(s
, -1))
3241 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3242 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3243 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_DEBUG_FLAGS
) == 0)
3244 /* Enable fast mode */
3245 s
->flags
|= __CMPXCHG_DOUBLE
;
3249 * The larger the object size is, the more pages we want on the partial
3250 * list to avoid pounding the page allocator excessively.
3252 set_min_partial(s
, ilog2(s
->size
) / 2);
3255 * cpu_partial determined the maximum number of objects kept in the
3256 * per cpu partial lists of a processor.
3258 * Per cpu partial lists mainly contain slabs that just have one
3259 * object freed. If they are used for allocation then they can be
3260 * filled up again with minimal effort. The slab will never hit the
3261 * per node partial lists and therefore no locking will be required.
3263 * This setting also determines
3265 * A) The number of objects from per cpu partial slabs dumped to the
3266 * per node list when we reach the limit.
3267 * B) The number of objects in cpu partial slabs to extract from the
3268 * per node list when we run out of per cpu objects. We only fetch
3269 * 50% to keep some capacity around for frees.
3271 if (!kmem_cache_has_cpu_partial(s
))
3273 else if (s
->size
>= PAGE_SIZE
)
3275 else if (s
->size
>= 1024)
3277 else if (s
->size
>= 256)
3278 s
->cpu_partial
= 13;
3280 s
->cpu_partial
= 30;
3283 s
->remote_node_defrag_ratio
= 1000;
3285 if (!init_kmem_cache_nodes(s
))
3288 if (alloc_kmem_cache_cpus(s
))
3291 free_kmem_cache_nodes(s
);
3293 if (flags
& SLAB_PANIC
)
3294 panic("Cannot create slab %s size=%lu realsize=%u "
3295 "order=%u offset=%u flags=%lx\n",
3296 s
->name
, (unsigned long)s
->size
, s
->size
,
3297 oo_order(s
->oo
), s
->offset
, flags
);
3301 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
3304 #ifdef CONFIG_SLUB_DEBUG
3305 void *addr
= page_address(page
);
3307 unsigned long *map
= kzalloc(BITS_TO_LONGS(page
->objects
) *
3308 sizeof(long), GFP_ATOMIC
);
3311 slab_err(s
, page
, text
, s
->name
);
3314 get_map(s
, page
, map
);
3315 for_each_object(p
, s
, addr
, page
->objects
) {
3317 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
3318 pr_err("INFO: Object 0x%p @offset=%tu\n", p
, p
- addr
);
3319 print_tracking(s
, p
);
3328 * Attempt to free all partial slabs on a node.
3329 * This is called from kmem_cache_close(). We must be the last thread
3330 * using the cache and therefore we do not need to lock anymore.
3332 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
3334 struct page
*page
, *h
;
3336 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
3338 __remove_partial(n
, page
);
3339 discard_slab(s
, page
);
3341 list_slab_objects(s
, page
,
3342 "Objects remaining in %s on kmem_cache_close()");
3348 * Release all resources used by a slab cache.
3350 static inline int kmem_cache_close(struct kmem_cache
*s
)
3353 struct kmem_cache_node
*n
;
3356 /* Attempt to free all objects */
3357 for_each_kmem_cache_node(s
, node
, n
) {
3359 if (n
->nr_partial
|| slabs_node(s
, node
))
3362 free_percpu(s
->cpu_slab
);
3363 free_kmem_cache_nodes(s
);
3367 int __kmem_cache_shutdown(struct kmem_cache
*s
)
3369 return kmem_cache_close(s
);
3372 /********************************************************************
3374 *******************************************************************/
3376 static int __init
setup_slub_min_order(char *str
)
3378 get_option(&str
, &slub_min_order
);
3383 __setup("slub_min_order=", setup_slub_min_order
);
3385 static int __init
setup_slub_max_order(char *str
)
3387 get_option(&str
, &slub_max_order
);
3388 slub_max_order
= min(slub_max_order
, MAX_ORDER
- 1);
3393 __setup("slub_max_order=", setup_slub_max_order
);
3395 static int __init
setup_slub_min_objects(char *str
)
3397 get_option(&str
, &slub_min_objects
);
3402 __setup("slub_min_objects=", setup_slub_min_objects
);
3404 void *__kmalloc(size_t size
, gfp_t flags
)
3406 struct kmem_cache
*s
;
3409 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3410 return kmalloc_large(size
, flags
);
3412 s
= kmalloc_slab(size
, flags
);
3414 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3417 ret
= slab_alloc(s
, flags
, _RET_IP_
);
3419 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
3421 kasan_kmalloc(s
, ret
, size
);
3425 EXPORT_SYMBOL(__kmalloc
);
3428 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
3433 flags
|= __GFP_COMP
| __GFP_NOTRACK
;
3434 page
= alloc_kmem_pages_node(node
, flags
, get_order(size
));
3436 ptr
= page_address(page
);
3438 kmalloc_large_node_hook(ptr
, size
, flags
);
3442 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3444 struct kmem_cache
*s
;
3447 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3448 ret
= kmalloc_large_node(size
, flags
, node
);
3450 trace_kmalloc_node(_RET_IP_
, ret
,
3451 size
, PAGE_SIZE
<< get_order(size
),
3457 s
= kmalloc_slab(size
, flags
);
3459 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3462 ret
= slab_alloc_node(s
, flags
, node
, _RET_IP_
);
3464 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
3466 kasan_kmalloc(s
, ret
, size
);
3470 EXPORT_SYMBOL(__kmalloc_node
);
3473 static size_t __ksize(const void *object
)
3477 if (unlikely(object
== ZERO_SIZE_PTR
))
3480 page
= virt_to_head_page(object
);
3482 if (unlikely(!PageSlab(page
))) {
3483 WARN_ON(!PageCompound(page
));
3484 return PAGE_SIZE
<< compound_order(page
);
3487 return slab_ksize(page
->slab_cache
);
3490 size_t ksize(const void *object
)
3492 size_t size
= __ksize(object
);
3493 /* We assume that ksize callers could use whole allocated area,
3494 so we need unpoison this area. */
3495 kasan_krealloc(object
, size
);
3498 EXPORT_SYMBOL(ksize
);
3500 void kfree(const void *x
)
3503 void *object
= (void *)x
;
3505 trace_kfree(_RET_IP_
, x
);
3507 if (unlikely(ZERO_OR_NULL_PTR(x
)))
3510 page
= virt_to_head_page(x
);
3511 if (unlikely(!PageSlab(page
))) {
3512 BUG_ON(!PageCompound(page
));
3514 __free_kmem_pages(page
, compound_order(page
));
3517 slab_free(page
->slab_cache
, page
, object
, _RET_IP_
);
3519 EXPORT_SYMBOL(kfree
);
3521 #define SHRINK_PROMOTE_MAX 32
3524 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3525 * up most to the head of the partial lists. New allocations will then
3526 * fill those up and thus they can be removed from the partial lists.
3528 * The slabs with the least items are placed last. This results in them
3529 * being allocated from last increasing the chance that the last objects
3530 * are freed in them.
3532 int __kmem_cache_shrink(struct kmem_cache
*s
, bool deactivate
)
3536 struct kmem_cache_node
*n
;
3539 struct list_head discard
;
3540 struct list_head promote
[SHRINK_PROMOTE_MAX
];
3541 unsigned long flags
;
3546 * Disable empty slabs caching. Used to avoid pinning offline
3547 * memory cgroups by kmem pages that can be freed.
3553 * s->cpu_partial is checked locklessly (see put_cpu_partial),
3554 * so we have to make sure the change is visible.
3556 kick_all_cpus_sync();
3560 for_each_kmem_cache_node(s
, node
, n
) {
3561 INIT_LIST_HEAD(&discard
);
3562 for (i
= 0; i
< SHRINK_PROMOTE_MAX
; i
++)
3563 INIT_LIST_HEAD(promote
+ i
);
3565 spin_lock_irqsave(&n
->list_lock
, flags
);
3568 * Build lists of slabs to discard or promote.
3570 * Note that concurrent frees may occur while we hold the
3571 * list_lock. page->inuse here is the upper limit.
3573 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
3574 int free
= page
->objects
- page
->inuse
;
3576 /* Do not reread page->inuse */
3579 /* We do not keep full slabs on the list */
3582 if (free
== page
->objects
) {
3583 list_move(&page
->lru
, &discard
);
3585 } else if (free
<= SHRINK_PROMOTE_MAX
)
3586 list_move(&page
->lru
, promote
+ free
- 1);
3590 * Promote the slabs filled up most to the head of the
3593 for (i
= SHRINK_PROMOTE_MAX
- 1; i
>= 0; i
--)
3594 list_splice(promote
+ i
, &n
->partial
);
3596 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3598 /* Release empty slabs */
3599 list_for_each_entry_safe(page
, t
, &discard
, lru
)
3600 discard_slab(s
, page
);
3602 if (slabs_node(s
, node
))
3609 static int slab_mem_going_offline_callback(void *arg
)
3611 struct kmem_cache
*s
;
3613 mutex_lock(&slab_mutex
);
3614 list_for_each_entry(s
, &slab_caches
, list
)
3615 __kmem_cache_shrink(s
, false);
3616 mutex_unlock(&slab_mutex
);
3621 static void slab_mem_offline_callback(void *arg
)
3623 struct kmem_cache_node
*n
;
3624 struct kmem_cache
*s
;
3625 struct memory_notify
*marg
= arg
;
3628 offline_node
= marg
->status_change_nid_normal
;
3631 * If the node still has available memory. we need kmem_cache_node
3634 if (offline_node
< 0)
3637 mutex_lock(&slab_mutex
);
3638 list_for_each_entry(s
, &slab_caches
, list
) {
3639 n
= get_node(s
, offline_node
);
3642 * if n->nr_slabs > 0, slabs still exist on the node
3643 * that is going down. We were unable to free them,
3644 * and offline_pages() function shouldn't call this
3645 * callback. So, we must fail.
3647 BUG_ON(slabs_node(s
, offline_node
));
3649 s
->node
[offline_node
] = NULL
;
3650 kmem_cache_free(kmem_cache_node
, n
);
3653 mutex_unlock(&slab_mutex
);
3656 static int slab_mem_going_online_callback(void *arg
)
3658 struct kmem_cache_node
*n
;
3659 struct kmem_cache
*s
;
3660 struct memory_notify
*marg
= arg
;
3661 int nid
= marg
->status_change_nid_normal
;
3665 * If the node's memory is already available, then kmem_cache_node is
3666 * already created. Nothing to do.
3672 * We are bringing a node online. No memory is available yet. We must
3673 * allocate a kmem_cache_node structure in order to bring the node
3676 mutex_lock(&slab_mutex
);
3677 list_for_each_entry(s
, &slab_caches
, list
) {
3679 * XXX: kmem_cache_alloc_node will fallback to other nodes
3680 * since memory is not yet available from the node that
3683 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
3688 init_kmem_cache_node(n
);
3692 mutex_unlock(&slab_mutex
);
3696 static int slab_memory_callback(struct notifier_block
*self
,
3697 unsigned long action
, void *arg
)
3702 case MEM_GOING_ONLINE
:
3703 ret
= slab_mem_going_online_callback(arg
);
3705 case MEM_GOING_OFFLINE
:
3706 ret
= slab_mem_going_offline_callback(arg
);
3709 case MEM_CANCEL_ONLINE
:
3710 slab_mem_offline_callback(arg
);
3713 case MEM_CANCEL_OFFLINE
:
3717 ret
= notifier_from_errno(ret
);
3723 static struct notifier_block slab_memory_callback_nb
= {
3724 .notifier_call
= slab_memory_callback
,
3725 .priority
= SLAB_CALLBACK_PRI
,
3728 /********************************************************************
3729 * Basic setup of slabs
3730 *******************************************************************/
3733 * Used for early kmem_cache structures that were allocated using
3734 * the page allocator. Allocate them properly then fix up the pointers
3735 * that may be pointing to the wrong kmem_cache structure.
3738 static struct kmem_cache
* __init
bootstrap(struct kmem_cache
*static_cache
)
3741 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
3742 struct kmem_cache_node
*n
;
3744 memcpy(s
, static_cache
, kmem_cache
->object_size
);
3747 * This runs very early, and only the boot processor is supposed to be
3748 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3751 __flush_cpu_slab(s
, smp_processor_id());
3752 for_each_kmem_cache_node(s
, node
, n
) {
3755 list_for_each_entry(p
, &n
->partial
, lru
)
3758 #ifdef CONFIG_SLUB_DEBUG
3759 list_for_each_entry(p
, &n
->full
, lru
)
3763 slab_init_memcg_params(s
);
3764 list_add(&s
->list
, &slab_caches
);
3768 void __init
kmem_cache_init(void)
3770 static __initdata
struct kmem_cache boot_kmem_cache
,
3771 boot_kmem_cache_node
;
3773 if (debug_guardpage_minorder())
3776 kmem_cache_node
= &boot_kmem_cache_node
;
3777 kmem_cache
= &boot_kmem_cache
;
3779 create_boot_cache(kmem_cache_node
, "kmem_cache_node",
3780 sizeof(struct kmem_cache_node
), SLAB_HWCACHE_ALIGN
);
3782 register_hotmemory_notifier(&slab_memory_callback_nb
);
3784 /* Able to allocate the per node structures */
3785 slab_state
= PARTIAL
;
3787 create_boot_cache(kmem_cache
, "kmem_cache",
3788 offsetof(struct kmem_cache
, node
) +
3789 nr_node_ids
* sizeof(struct kmem_cache_node
*),
3790 SLAB_HWCACHE_ALIGN
);
3792 kmem_cache
= bootstrap(&boot_kmem_cache
);
3795 * Allocate kmem_cache_node properly from the kmem_cache slab.
3796 * kmem_cache_node is separately allocated so no need to
3797 * update any list pointers.
3799 kmem_cache_node
= bootstrap(&boot_kmem_cache_node
);
3801 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3802 setup_kmalloc_cache_index_table();
3803 create_kmalloc_caches(0);
3806 register_cpu_notifier(&slab_notifier
);
3809 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
3811 slub_min_order
, slub_max_order
, slub_min_objects
,
3812 nr_cpu_ids
, nr_node_ids
);
3815 void __init
kmem_cache_init_late(void)
3820 __kmem_cache_alias(const char *name
, size_t size
, size_t align
,
3821 unsigned long flags
, void (*ctor
)(void *))
3823 struct kmem_cache
*s
, *c
;
3825 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3830 * Adjust the object sizes so that we clear
3831 * the complete object on kzalloc.
3833 s
->object_size
= max(s
->object_size
, (int)size
);
3834 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3836 for_each_memcg_cache(c
, s
) {
3837 c
->object_size
= s
->object_size
;
3838 c
->inuse
= max_t(int, c
->inuse
,
3839 ALIGN(size
, sizeof(void *)));
3842 if (sysfs_slab_alias(s
, name
)) {
3851 int __kmem_cache_create(struct kmem_cache
*s
, unsigned long flags
)
3855 err
= kmem_cache_open(s
, flags
);
3859 /* Mutex is not taken during early boot */
3860 if (slab_state
<= UP
)
3863 memcg_propagate_slab_attrs(s
);
3864 err
= sysfs_slab_add(s
);
3866 kmem_cache_close(s
);
3873 * Use the cpu notifier to insure that the cpu slabs are flushed when
3876 static int slab_cpuup_callback(struct notifier_block
*nfb
,
3877 unsigned long action
, void *hcpu
)
3879 long cpu
= (long)hcpu
;
3880 struct kmem_cache
*s
;
3881 unsigned long flags
;
3884 case CPU_UP_CANCELED
:
3885 case CPU_UP_CANCELED_FROZEN
:
3887 case CPU_DEAD_FROZEN
:
3888 mutex_lock(&slab_mutex
);
3889 list_for_each_entry(s
, &slab_caches
, list
) {
3890 local_irq_save(flags
);
3891 __flush_cpu_slab(s
, cpu
);
3892 local_irq_restore(flags
);
3894 mutex_unlock(&slab_mutex
);
3902 static struct notifier_block slab_notifier
= {
3903 .notifier_call
= slab_cpuup_callback
3908 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
3910 struct kmem_cache
*s
;
3913 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3914 return kmalloc_large(size
, gfpflags
);
3916 s
= kmalloc_slab(size
, gfpflags
);
3918 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3921 ret
= slab_alloc(s
, gfpflags
, caller
);
3923 /* Honor the call site pointer we received. */
3924 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
3930 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3931 int node
, unsigned long caller
)
3933 struct kmem_cache
*s
;
3936 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3937 ret
= kmalloc_large_node(size
, gfpflags
, node
);
3939 trace_kmalloc_node(caller
, ret
,
3940 size
, PAGE_SIZE
<< get_order(size
),
3946 s
= kmalloc_slab(size
, gfpflags
);
3948 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3951 ret
= slab_alloc_node(s
, gfpflags
, node
, caller
);
3953 /* Honor the call site pointer we received. */
3954 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
3961 static int count_inuse(struct page
*page
)
3966 static int count_total(struct page
*page
)
3968 return page
->objects
;
3972 #ifdef CONFIG_SLUB_DEBUG
3973 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3977 void *addr
= page_address(page
);
3979 if (!check_slab(s
, page
) ||
3980 !on_freelist(s
, page
, NULL
))
3983 /* Now we know that a valid freelist exists */
3984 bitmap_zero(map
, page
->objects
);
3986 get_map(s
, page
, map
);
3987 for_each_object(p
, s
, addr
, page
->objects
) {
3988 if (test_bit(slab_index(p
, s
, addr
), map
))
3989 if (!check_object(s
, page
, p
, SLUB_RED_INACTIVE
))
3993 for_each_object(p
, s
, addr
, page
->objects
)
3994 if (!test_bit(slab_index(p
, s
, addr
), map
))
3995 if (!check_object(s
, page
, p
, SLUB_RED_ACTIVE
))
4000 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
4004 validate_slab(s
, page
, map
);
4008 static int validate_slab_node(struct kmem_cache
*s
,
4009 struct kmem_cache_node
*n
, unsigned long *map
)
4011 unsigned long count
= 0;
4013 unsigned long flags
;
4015 spin_lock_irqsave(&n
->list_lock
, flags
);
4017 list_for_each_entry(page
, &n
->partial
, lru
) {
4018 validate_slab_slab(s
, page
, map
);
4021 if (count
!= n
->nr_partial
)
4022 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4023 s
->name
, count
, n
->nr_partial
);
4025 if (!(s
->flags
& SLAB_STORE_USER
))
4028 list_for_each_entry(page
, &n
->full
, lru
) {
4029 validate_slab_slab(s
, page
, map
);
4032 if (count
!= atomic_long_read(&n
->nr_slabs
))
4033 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4034 s
->name
, count
, atomic_long_read(&n
->nr_slabs
));
4037 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4041 static long validate_slab_cache(struct kmem_cache
*s
)
4044 unsigned long count
= 0;
4045 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4046 sizeof(unsigned long), GFP_KERNEL
);
4047 struct kmem_cache_node
*n
;
4053 for_each_kmem_cache_node(s
, node
, n
)
4054 count
+= validate_slab_node(s
, n
, map
);
4059 * Generate lists of code addresses where slabcache objects are allocated
4064 unsigned long count
;
4071 DECLARE_BITMAP(cpus
, NR_CPUS
);
4077 unsigned long count
;
4078 struct location
*loc
;
4081 static void free_loc_track(struct loc_track
*t
)
4084 free_pages((unsigned long)t
->loc
,
4085 get_order(sizeof(struct location
) * t
->max
));
4088 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
4093 order
= get_order(sizeof(struct location
) * max
);
4095 l
= (void *)__get_free_pages(flags
, order
);
4100 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
4108 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
4109 const struct track
*track
)
4111 long start
, end
, pos
;
4113 unsigned long caddr
;
4114 unsigned long age
= jiffies
- track
->when
;
4120 pos
= start
+ (end
- start
+ 1) / 2;
4123 * There is nothing at "end". If we end up there
4124 * we need to add something to before end.
4129 caddr
= t
->loc
[pos
].addr
;
4130 if (track
->addr
== caddr
) {
4136 if (age
< l
->min_time
)
4138 if (age
> l
->max_time
)
4141 if (track
->pid
< l
->min_pid
)
4142 l
->min_pid
= track
->pid
;
4143 if (track
->pid
> l
->max_pid
)
4144 l
->max_pid
= track
->pid
;
4146 cpumask_set_cpu(track
->cpu
,
4147 to_cpumask(l
->cpus
));
4149 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4153 if (track
->addr
< caddr
)
4160 * Not found. Insert new tracking element.
4162 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
4168 (t
->count
- pos
) * sizeof(struct location
));
4171 l
->addr
= track
->addr
;
4175 l
->min_pid
= track
->pid
;
4176 l
->max_pid
= track
->pid
;
4177 cpumask_clear(to_cpumask(l
->cpus
));
4178 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
4179 nodes_clear(l
->nodes
);
4180 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4184 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
4185 struct page
*page
, enum track_item alloc
,
4188 void *addr
= page_address(page
);
4191 bitmap_zero(map
, page
->objects
);
4192 get_map(s
, page
, map
);
4194 for_each_object(p
, s
, addr
, page
->objects
)
4195 if (!test_bit(slab_index(p
, s
, addr
), map
))
4196 add_location(t
, s
, get_track(s
, p
, alloc
));
4199 static int list_locations(struct kmem_cache
*s
, char *buf
,
4200 enum track_item alloc
)
4204 struct loc_track t
= { 0, 0, NULL
};
4206 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4207 sizeof(unsigned long), GFP_KERNEL
);
4208 struct kmem_cache_node
*n
;
4210 if (!map
|| !alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
4213 return sprintf(buf
, "Out of memory\n");
4215 /* Push back cpu slabs */
4218 for_each_kmem_cache_node(s
, node
, n
) {
4219 unsigned long flags
;
4222 if (!atomic_long_read(&n
->nr_slabs
))
4225 spin_lock_irqsave(&n
->list_lock
, flags
);
4226 list_for_each_entry(page
, &n
->partial
, lru
)
4227 process_slab(&t
, s
, page
, alloc
, map
);
4228 list_for_each_entry(page
, &n
->full
, lru
)
4229 process_slab(&t
, s
, page
, alloc
, map
);
4230 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4233 for (i
= 0; i
< t
.count
; i
++) {
4234 struct location
*l
= &t
.loc
[i
];
4236 if (len
> PAGE_SIZE
- KSYM_SYMBOL_LEN
- 100)
4238 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
4241 len
+= sprintf(buf
+ len
, "%pS", (void *)l
->addr
);
4243 len
+= sprintf(buf
+ len
, "<not-available>");
4245 if (l
->sum_time
!= l
->min_time
) {
4246 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
4248 (long)div_u64(l
->sum_time
, l
->count
),
4251 len
+= sprintf(buf
+ len
, " age=%ld",
4254 if (l
->min_pid
!= l
->max_pid
)
4255 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
4256 l
->min_pid
, l
->max_pid
);
4258 len
+= sprintf(buf
+ len
, " pid=%ld",
4261 if (num_online_cpus() > 1 &&
4262 !cpumask_empty(to_cpumask(l
->cpus
)) &&
4263 len
< PAGE_SIZE
- 60)
4264 len
+= scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4266 cpumask_pr_args(to_cpumask(l
->cpus
)));
4268 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
) &&
4269 len
< PAGE_SIZE
- 60)
4270 len
+= scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4272 nodemask_pr_args(&l
->nodes
));
4274 len
+= sprintf(buf
+ len
, "\n");
4280 len
+= sprintf(buf
, "No data\n");
4285 #ifdef SLUB_RESILIENCY_TEST
4286 static void __init
resiliency_test(void)
4290 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 16 || KMALLOC_SHIFT_HIGH
< 10);
4292 pr_err("SLUB resiliency testing\n");
4293 pr_err("-----------------------\n");
4294 pr_err("A. Corruption after allocation\n");
4296 p
= kzalloc(16, GFP_KERNEL
);
4298 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4301 validate_slab_cache(kmalloc_caches
[4]);
4303 /* Hmmm... The next two are dangerous */
4304 p
= kzalloc(32, GFP_KERNEL
);
4305 p
[32 + sizeof(void *)] = 0x34;
4306 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4308 pr_err("If allocated object is overwritten then not detectable\n\n");
4310 validate_slab_cache(kmalloc_caches
[5]);
4311 p
= kzalloc(64, GFP_KERNEL
);
4312 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
4314 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4316 pr_err("If allocated object is overwritten then not detectable\n\n");
4317 validate_slab_cache(kmalloc_caches
[6]);
4319 pr_err("\nB. Corruption after free\n");
4320 p
= kzalloc(128, GFP_KERNEL
);
4323 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
4324 validate_slab_cache(kmalloc_caches
[7]);
4326 p
= kzalloc(256, GFP_KERNEL
);
4329 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
4330 validate_slab_cache(kmalloc_caches
[8]);
4332 p
= kzalloc(512, GFP_KERNEL
);
4335 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
4336 validate_slab_cache(kmalloc_caches
[9]);
4340 static void resiliency_test(void) {};
4345 enum slab_stat_type
{
4346 SL_ALL
, /* All slabs */
4347 SL_PARTIAL
, /* Only partially allocated slabs */
4348 SL_CPU
, /* Only slabs used for cpu caches */
4349 SL_OBJECTS
, /* Determine allocated objects not slabs */
4350 SL_TOTAL
/* Determine object capacity not slabs */
4353 #define SO_ALL (1 << SL_ALL)
4354 #define SO_PARTIAL (1 << SL_PARTIAL)
4355 #define SO_CPU (1 << SL_CPU)
4356 #define SO_OBJECTS (1 << SL_OBJECTS)
4357 #define SO_TOTAL (1 << SL_TOTAL)
4359 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
4360 char *buf
, unsigned long flags
)
4362 unsigned long total
= 0;
4365 unsigned long *nodes
;
4367 nodes
= kzalloc(sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
4371 if (flags
& SO_CPU
) {
4374 for_each_possible_cpu(cpu
) {
4375 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
,
4380 page
= READ_ONCE(c
->page
);
4384 node
= page_to_nid(page
);
4385 if (flags
& SO_TOTAL
)
4387 else if (flags
& SO_OBJECTS
)
4395 page
= READ_ONCE(c
->partial
);
4397 node
= page_to_nid(page
);
4398 if (flags
& SO_TOTAL
)
4400 else if (flags
& SO_OBJECTS
)
4411 #ifdef CONFIG_SLUB_DEBUG
4412 if (flags
& SO_ALL
) {
4413 struct kmem_cache_node
*n
;
4415 for_each_kmem_cache_node(s
, node
, n
) {
4417 if (flags
& SO_TOTAL
)
4418 x
= atomic_long_read(&n
->total_objects
);
4419 else if (flags
& SO_OBJECTS
)
4420 x
= atomic_long_read(&n
->total_objects
) -
4421 count_partial(n
, count_free
);
4423 x
= atomic_long_read(&n
->nr_slabs
);
4430 if (flags
& SO_PARTIAL
) {
4431 struct kmem_cache_node
*n
;
4433 for_each_kmem_cache_node(s
, node
, n
) {
4434 if (flags
& SO_TOTAL
)
4435 x
= count_partial(n
, count_total
);
4436 else if (flags
& SO_OBJECTS
)
4437 x
= count_partial(n
, count_inuse
);
4444 x
= sprintf(buf
, "%lu", total
);
4446 for (node
= 0; node
< nr_node_ids
; node
++)
4448 x
+= sprintf(buf
+ x
, " N%d=%lu",
4453 return x
+ sprintf(buf
+ x
, "\n");
4456 #ifdef CONFIG_SLUB_DEBUG
4457 static int any_slab_objects(struct kmem_cache
*s
)
4460 struct kmem_cache_node
*n
;
4462 for_each_kmem_cache_node(s
, node
, n
)
4463 if (atomic_long_read(&n
->total_objects
))
4470 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4471 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4473 struct slab_attribute
{
4474 struct attribute attr
;
4475 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
4476 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
4479 #define SLAB_ATTR_RO(_name) \
4480 static struct slab_attribute _name##_attr = \
4481 __ATTR(_name, 0400, _name##_show, NULL)
4483 #define SLAB_ATTR(_name) \
4484 static struct slab_attribute _name##_attr = \
4485 __ATTR(_name, 0600, _name##_show, _name##_store)
4487 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
4489 return sprintf(buf
, "%d\n", s
->size
);
4491 SLAB_ATTR_RO(slab_size
);
4493 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
4495 return sprintf(buf
, "%d\n", s
->align
);
4497 SLAB_ATTR_RO(align
);
4499 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
4501 return sprintf(buf
, "%d\n", s
->object_size
);
4503 SLAB_ATTR_RO(object_size
);
4505 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
4507 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
4509 SLAB_ATTR_RO(objs_per_slab
);
4511 static ssize_t
order_store(struct kmem_cache
*s
,
4512 const char *buf
, size_t length
)
4514 unsigned long order
;
4517 err
= kstrtoul(buf
, 10, &order
);
4521 if (order
> slub_max_order
|| order
< slub_min_order
)
4524 calculate_sizes(s
, order
);
4528 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
4530 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
4534 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
4536 return sprintf(buf
, "%lu\n", s
->min_partial
);
4539 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
4545 err
= kstrtoul(buf
, 10, &min
);
4549 set_min_partial(s
, min
);
4552 SLAB_ATTR(min_partial
);
4554 static ssize_t
cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4556 return sprintf(buf
, "%u\n", s
->cpu_partial
);
4559 static ssize_t
cpu_partial_store(struct kmem_cache
*s
, const char *buf
,
4562 unsigned long objects
;
4565 err
= kstrtoul(buf
, 10, &objects
);
4568 if (objects
&& !kmem_cache_has_cpu_partial(s
))
4571 s
->cpu_partial
= objects
;
4575 SLAB_ATTR(cpu_partial
);
4577 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
4581 return sprintf(buf
, "%pS\n", s
->ctor
);
4585 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
4587 return sprintf(buf
, "%d\n", s
->refcount
< 0 ? 0 : s
->refcount
- 1);
4589 SLAB_ATTR_RO(aliases
);
4591 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
4593 return show_slab_objects(s
, buf
, SO_PARTIAL
);
4595 SLAB_ATTR_RO(partial
);
4597 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
4599 return show_slab_objects(s
, buf
, SO_CPU
);
4601 SLAB_ATTR_RO(cpu_slabs
);
4603 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
4605 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
4607 SLAB_ATTR_RO(objects
);
4609 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
4611 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
4613 SLAB_ATTR_RO(objects_partial
);
4615 static ssize_t
slabs_cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4622 for_each_online_cpu(cpu
) {
4623 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
)->partial
;
4626 pages
+= page
->pages
;
4627 objects
+= page
->pobjects
;
4631 len
= sprintf(buf
, "%d(%d)", objects
, pages
);
4634 for_each_online_cpu(cpu
) {
4635 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
) ->partial
;
4637 if (page
&& len
< PAGE_SIZE
- 20)
4638 len
+= sprintf(buf
+ len
, " C%d=%d(%d)", cpu
,
4639 page
->pobjects
, page
->pages
);
4642 return len
+ sprintf(buf
+ len
, "\n");
4644 SLAB_ATTR_RO(slabs_cpu_partial
);
4646 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
4648 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
4651 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
4652 const char *buf
, size_t length
)
4654 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
4656 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
4659 SLAB_ATTR(reclaim_account
);
4661 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
4663 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
4665 SLAB_ATTR_RO(hwcache_align
);
4667 #ifdef CONFIG_ZONE_DMA
4668 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
4670 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
4672 SLAB_ATTR_RO(cache_dma
);
4675 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
4677 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
4679 SLAB_ATTR_RO(destroy_by_rcu
);
4681 static ssize_t
reserved_show(struct kmem_cache
*s
, char *buf
)
4683 return sprintf(buf
, "%d\n", s
->reserved
);
4685 SLAB_ATTR_RO(reserved
);
4687 #ifdef CONFIG_SLUB_DEBUG
4688 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
4690 return show_slab_objects(s
, buf
, SO_ALL
);
4692 SLAB_ATTR_RO(slabs
);
4694 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
4696 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
4698 SLAB_ATTR_RO(total_objects
);
4700 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
4702 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
4705 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
4706 const char *buf
, size_t length
)
4708 s
->flags
&= ~SLAB_DEBUG_FREE
;
4709 if (buf
[0] == '1') {
4710 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4711 s
->flags
|= SLAB_DEBUG_FREE
;
4715 SLAB_ATTR(sanity_checks
);
4717 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
4719 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
4722 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
4726 * Tracing a merged cache is going to give confusing results
4727 * as well as cause other issues like converting a mergeable
4728 * cache into an umergeable one.
4730 if (s
->refcount
> 1)
4733 s
->flags
&= ~SLAB_TRACE
;
4734 if (buf
[0] == '1') {
4735 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4736 s
->flags
|= SLAB_TRACE
;
4742 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
4744 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
4747 static ssize_t
red_zone_store(struct kmem_cache
*s
,
4748 const char *buf
, size_t length
)
4750 if (any_slab_objects(s
))
4753 s
->flags
&= ~SLAB_RED_ZONE
;
4754 if (buf
[0] == '1') {
4755 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4756 s
->flags
|= SLAB_RED_ZONE
;
4758 calculate_sizes(s
, -1);
4761 SLAB_ATTR(red_zone
);
4763 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
4765 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
4768 static ssize_t
poison_store(struct kmem_cache
*s
,
4769 const char *buf
, size_t length
)
4771 if (any_slab_objects(s
))
4774 s
->flags
&= ~SLAB_POISON
;
4775 if (buf
[0] == '1') {
4776 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4777 s
->flags
|= SLAB_POISON
;
4779 calculate_sizes(s
, -1);
4784 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
4786 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
4789 static ssize_t
store_user_store(struct kmem_cache
*s
,
4790 const char *buf
, size_t length
)
4792 if (any_slab_objects(s
))
4795 s
->flags
&= ~SLAB_STORE_USER
;
4796 if (buf
[0] == '1') {
4797 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4798 s
->flags
|= SLAB_STORE_USER
;
4800 calculate_sizes(s
, -1);
4803 SLAB_ATTR(store_user
);
4805 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4810 static ssize_t
validate_store(struct kmem_cache
*s
,
4811 const char *buf
, size_t length
)
4815 if (buf
[0] == '1') {
4816 ret
= validate_slab_cache(s
);
4822 SLAB_ATTR(validate
);
4824 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4826 if (!(s
->flags
& SLAB_STORE_USER
))
4828 return list_locations(s
, buf
, TRACK_ALLOC
);
4830 SLAB_ATTR_RO(alloc_calls
);
4832 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4834 if (!(s
->flags
& SLAB_STORE_USER
))
4836 return list_locations(s
, buf
, TRACK_FREE
);
4838 SLAB_ATTR_RO(free_calls
);
4839 #endif /* CONFIG_SLUB_DEBUG */
4841 #ifdef CONFIG_FAILSLAB
4842 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
4844 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
4847 static ssize_t
failslab_store(struct kmem_cache
*s
, const char *buf
,
4850 if (s
->refcount
> 1)
4853 s
->flags
&= ~SLAB_FAILSLAB
;
4855 s
->flags
|= SLAB_FAILSLAB
;
4858 SLAB_ATTR(failslab
);
4861 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4866 static ssize_t
shrink_store(struct kmem_cache
*s
,
4867 const char *buf
, size_t length
)
4870 kmem_cache_shrink(s
);
4878 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4880 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4883 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4884 const char *buf
, size_t length
)
4886 unsigned long ratio
;
4889 err
= kstrtoul(buf
, 10, &ratio
);
4894 s
->remote_node_defrag_ratio
= ratio
* 10;
4898 SLAB_ATTR(remote_node_defrag_ratio
);
4901 #ifdef CONFIG_SLUB_STATS
4902 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
4904 unsigned long sum
= 0;
4907 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
4912 for_each_online_cpu(cpu
) {
4913 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
4919 len
= sprintf(buf
, "%lu", sum
);
4922 for_each_online_cpu(cpu
) {
4923 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
4924 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
4928 return len
+ sprintf(buf
+ len
, "\n");
4931 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
4935 for_each_online_cpu(cpu
)
4936 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
4939 #define STAT_ATTR(si, text) \
4940 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4942 return show_stat(s, buf, si); \
4944 static ssize_t text##_store(struct kmem_cache *s, \
4945 const char *buf, size_t length) \
4947 if (buf[0] != '0') \
4949 clear_stat(s, si); \
4954 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4955 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
4956 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
4957 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
4958 STAT_ATTR(FREE_FROZEN
, free_frozen
);
4959 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
4960 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
4961 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
4962 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
4963 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
4964 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
4965 STAT_ATTR(FREE_SLAB
, free_slab
);
4966 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
4967 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
4968 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
4969 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4970 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4971 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4972 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
4973 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
4974 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
4975 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
4976 STAT_ATTR(CPU_PARTIAL_ALLOC
, cpu_partial_alloc
);
4977 STAT_ATTR(CPU_PARTIAL_FREE
, cpu_partial_free
);
4978 STAT_ATTR(CPU_PARTIAL_NODE
, cpu_partial_node
);
4979 STAT_ATTR(CPU_PARTIAL_DRAIN
, cpu_partial_drain
);
4982 static struct attribute
*slab_attrs
[] = {
4983 &slab_size_attr
.attr
,
4984 &object_size_attr
.attr
,
4985 &objs_per_slab_attr
.attr
,
4987 &min_partial_attr
.attr
,
4988 &cpu_partial_attr
.attr
,
4990 &objects_partial_attr
.attr
,
4992 &cpu_slabs_attr
.attr
,
4996 &hwcache_align_attr
.attr
,
4997 &reclaim_account_attr
.attr
,
4998 &destroy_by_rcu_attr
.attr
,
5000 &reserved_attr
.attr
,
5001 &slabs_cpu_partial_attr
.attr
,
5002 #ifdef CONFIG_SLUB_DEBUG
5003 &total_objects_attr
.attr
,
5005 &sanity_checks_attr
.attr
,
5007 &red_zone_attr
.attr
,
5009 &store_user_attr
.attr
,
5010 &validate_attr
.attr
,
5011 &alloc_calls_attr
.attr
,
5012 &free_calls_attr
.attr
,
5014 #ifdef CONFIG_ZONE_DMA
5015 &cache_dma_attr
.attr
,
5018 &remote_node_defrag_ratio_attr
.attr
,
5020 #ifdef CONFIG_SLUB_STATS
5021 &alloc_fastpath_attr
.attr
,
5022 &alloc_slowpath_attr
.attr
,
5023 &free_fastpath_attr
.attr
,
5024 &free_slowpath_attr
.attr
,
5025 &free_frozen_attr
.attr
,
5026 &free_add_partial_attr
.attr
,
5027 &free_remove_partial_attr
.attr
,
5028 &alloc_from_partial_attr
.attr
,
5029 &alloc_slab_attr
.attr
,
5030 &alloc_refill_attr
.attr
,
5031 &alloc_node_mismatch_attr
.attr
,
5032 &free_slab_attr
.attr
,
5033 &cpuslab_flush_attr
.attr
,
5034 &deactivate_full_attr
.attr
,
5035 &deactivate_empty_attr
.attr
,
5036 &deactivate_to_head_attr
.attr
,
5037 &deactivate_to_tail_attr
.attr
,
5038 &deactivate_remote_frees_attr
.attr
,
5039 &deactivate_bypass_attr
.attr
,
5040 &order_fallback_attr
.attr
,
5041 &cmpxchg_double_fail_attr
.attr
,
5042 &cmpxchg_double_cpu_fail_attr
.attr
,
5043 &cpu_partial_alloc_attr
.attr
,
5044 &cpu_partial_free_attr
.attr
,
5045 &cpu_partial_node_attr
.attr
,
5046 &cpu_partial_drain_attr
.attr
,
5048 #ifdef CONFIG_FAILSLAB
5049 &failslab_attr
.attr
,
5055 static struct attribute_group slab_attr_group
= {
5056 .attrs
= slab_attrs
,
5059 static ssize_t
slab_attr_show(struct kobject
*kobj
,
5060 struct attribute
*attr
,
5063 struct slab_attribute
*attribute
;
5064 struct kmem_cache
*s
;
5067 attribute
= to_slab_attr(attr
);
5070 if (!attribute
->show
)
5073 err
= attribute
->show(s
, buf
);
5078 static ssize_t
slab_attr_store(struct kobject
*kobj
,
5079 struct attribute
*attr
,
5080 const char *buf
, size_t len
)
5082 struct slab_attribute
*attribute
;
5083 struct kmem_cache
*s
;
5086 attribute
= to_slab_attr(attr
);
5089 if (!attribute
->store
)
5092 err
= attribute
->store(s
, buf
, len
);
5093 #ifdef CONFIG_MEMCG_KMEM
5094 if (slab_state
>= FULL
&& err
>= 0 && is_root_cache(s
)) {
5095 struct kmem_cache
*c
;
5097 mutex_lock(&slab_mutex
);
5098 if (s
->max_attr_size
< len
)
5099 s
->max_attr_size
= len
;
5102 * This is a best effort propagation, so this function's return
5103 * value will be determined by the parent cache only. This is
5104 * basically because not all attributes will have a well
5105 * defined semantics for rollbacks - most of the actions will
5106 * have permanent effects.
5108 * Returning the error value of any of the children that fail
5109 * is not 100 % defined, in the sense that users seeing the
5110 * error code won't be able to know anything about the state of
5113 * Only returning the error code for the parent cache at least
5114 * has well defined semantics. The cache being written to
5115 * directly either failed or succeeded, in which case we loop
5116 * through the descendants with best-effort propagation.
5118 for_each_memcg_cache(c
, s
)
5119 attribute
->store(c
, buf
, len
);
5120 mutex_unlock(&slab_mutex
);
5126 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
)
5128 #ifdef CONFIG_MEMCG_KMEM
5130 char *buffer
= NULL
;
5131 struct kmem_cache
*root_cache
;
5133 if (is_root_cache(s
))
5136 root_cache
= s
->memcg_params
.root_cache
;
5139 * This mean this cache had no attribute written. Therefore, no point
5140 * in copying default values around
5142 if (!root_cache
->max_attr_size
)
5145 for (i
= 0; i
< ARRAY_SIZE(slab_attrs
); i
++) {
5148 struct slab_attribute
*attr
= to_slab_attr(slab_attrs
[i
]);
5150 if (!attr
|| !attr
->store
|| !attr
->show
)
5154 * It is really bad that we have to allocate here, so we will
5155 * do it only as a fallback. If we actually allocate, though,
5156 * we can just use the allocated buffer until the end.
5158 * Most of the slub attributes will tend to be very small in
5159 * size, but sysfs allows buffers up to a page, so they can
5160 * theoretically happen.
5164 else if (root_cache
->max_attr_size
< ARRAY_SIZE(mbuf
))
5167 buffer
= (char *) get_zeroed_page(GFP_KERNEL
);
5168 if (WARN_ON(!buffer
))
5173 attr
->show(root_cache
, buf
);
5174 attr
->store(s
, buf
, strlen(buf
));
5178 free_page((unsigned long)buffer
);
5182 static void kmem_cache_release(struct kobject
*k
)
5184 slab_kmem_cache_release(to_slab(k
));
5187 static const struct sysfs_ops slab_sysfs_ops
= {
5188 .show
= slab_attr_show
,
5189 .store
= slab_attr_store
,
5192 static struct kobj_type slab_ktype
= {
5193 .sysfs_ops
= &slab_sysfs_ops
,
5194 .release
= kmem_cache_release
,
5197 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
5199 struct kobj_type
*ktype
= get_ktype(kobj
);
5201 if (ktype
== &slab_ktype
)
5206 static const struct kset_uevent_ops slab_uevent_ops
= {
5207 .filter
= uevent_filter
,
5210 static struct kset
*slab_kset
;
5212 static inline struct kset
*cache_kset(struct kmem_cache
*s
)
5214 #ifdef CONFIG_MEMCG_KMEM
5215 if (!is_root_cache(s
))
5216 return s
->memcg_params
.root_cache
->memcg_kset
;
5221 #define ID_STR_LENGTH 64
5223 /* Create a unique string id for a slab cache:
5225 * Format :[flags-]size
5227 static char *create_unique_id(struct kmem_cache
*s
)
5229 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
5236 * First flags affecting slabcache operations. We will only
5237 * get here for aliasable slabs so we do not need to support
5238 * too many flags. The flags here must cover all flags that
5239 * are matched during merging to guarantee that the id is
5242 if (s
->flags
& SLAB_CACHE_DMA
)
5244 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
5246 if (s
->flags
& SLAB_DEBUG_FREE
)
5248 if (!(s
->flags
& SLAB_NOTRACK
))
5252 p
+= sprintf(p
, "%07d", s
->size
);
5254 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
5258 static int sysfs_slab_add(struct kmem_cache
*s
)
5262 int unmergeable
= slab_unmergeable(s
);
5266 * Slabcache can never be merged so we can use the name proper.
5267 * This is typically the case for debug situations. In that
5268 * case we can catch duplicate names easily.
5270 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
5274 * Create a unique name for the slab as a target
5277 name
= create_unique_id(s
);
5280 s
->kobj
.kset
= cache_kset(s
);
5281 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, "%s", name
);
5285 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
5289 #ifdef CONFIG_MEMCG_KMEM
5290 if (is_root_cache(s
)) {
5291 s
->memcg_kset
= kset_create_and_add("cgroup", NULL
, &s
->kobj
);
5292 if (!s
->memcg_kset
) {
5299 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
5301 /* Setup first alias */
5302 sysfs_slab_alias(s
, s
->name
);
5309 kobject_del(&s
->kobj
);
5313 void sysfs_slab_remove(struct kmem_cache
*s
)
5315 if (slab_state
< FULL
)
5317 * Sysfs has not been setup yet so no need to remove the
5322 #ifdef CONFIG_MEMCG_KMEM
5323 kset_unregister(s
->memcg_kset
);
5325 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
5326 kobject_del(&s
->kobj
);
5327 kobject_put(&s
->kobj
);
5331 * Need to buffer aliases during bootup until sysfs becomes
5332 * available lest we lose that information.
5334 struct saved_alias
{
5335 struct kmem_cache
*s
;
5337 struct saved_alias
*next
;
5340 static struct saved_alias
*alias_list
;
5342 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5344 struct saved_alias
*al
;
5346 if (slab_state
== FULL
) {
5348 * If we have a leftover link then remove it.
5350 sysfs_remove_link(&slab_kset
->kobj
, name
);
5351 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5354 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5360 al
->next
= alias_list
;
5365 static int __init
slab_sysfs_init(void)
5367 struct kmem_cache
*s
;
5370 mutex_lock(&slab_mutex
);
5372 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
5374 mutex_unlock(&slab_mutex
);
5375 pr_err("Cannot register slab subsystem.\n");
5381 list_for_each_entry(s
, &slab_caches
, list
) {
5382 err
= sysfs_slab_add(s
);
5384 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5388 while (alias_list
) {
5389 struct saved_alias
*al
= alias_list
;
5391 alias_list
= alias_list
->next
;
5392 err
= sysfs_slab_alias(al
->s
, al
->name
);
5394 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5399 mutex_unlock(&slab_mutex
);
5404 __initcall(slab_sysfs_init
);
5405 #endif /* CONFIG_SYSFS */
5408 * The /proc/slabinfo ABI
5410 #ifdef CONFIG_SLABINFO
5411 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
)
5413 unsigned long nr_slabs
= 0;
5414 unsigned long nr_objs
= 0;
5415 unsigned long nr_free
= 0;
5417 struct kmem_cache_node
*n
;
5419 for_each_kmem_cache_node(s
, node
, n
) {
5420 nr_slabs
+= node_nr_slabs(n
);
5421 nr_objs
+= node_nr_objs(n
);
5422 nr_free
+= count_partial(n
, count_free
);
5425 sinfo
->active_objs
= nr_objs
- nr_free
;
5426 sinfo
->num_objs
= nr_objs
;
5427 sinfo
->active_slabs
= nr_slabs
;
5428 sinfo
->num_slabs
= nr_slabs
;
5429 sinfo
->objects_per_slab
= oo_objects(s
->oo
);
5430 sinfo
->cache_order
= oo_order(s
->oo
);
5433 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
)
5437 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
5438 size_t count
, loff_t
*ppos
)
5442 #endif /* CONFIG_SLABINFO */