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 #ifdef CONFIG_SLUB_DEBUG_ON
463 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
465 static int slub_debug
;
468 static char *slub_debug_slabs
;
469 static int disable_higher_order_debug
;
472 * slub is about to manipulate internal object metadata. This memory lies
473 * outside the range of the allocated object, so accessing it would normally
474 * be reported by kasan as a bounds error. metadata_access_enable() is used
475 * to tell kasan that these accesses are OK.
477 static inline void metadata_access_enable(void)
479 kasan_disable_current();
482 static inline void metadata_access_disable(void)
484 kasan_enable_current();
490 static void print_section(char *text
, u8
*addr
, unsigned int length
)
492 metadata_access_enable();
493 print_hex_dump(KERN_ERR
, text
, DUMP_PREFIX_ADDRESS
, 16, 1, addr
,
495 metadata_access_disable();
498 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
499 enum track_item alloc
)
504 p
= object
+ s
->offset
+ sizeof(void *);
506 p
= object
+ s
->inuse
;
511 static void set_track(struct kmem_cache
*s
, void *object
,
512 enum track_item alloc
, unsigned long addr
)
514 struct track
*p
= get_track(s
, object
, alloc
);
517 #ifdef CONFIG_STACKTRACE
518 struct stack_trace trace
;
521 trace
.nr_entries
= 0;
522 trace
.max_entries
= TRACK_ADDRS_COUNT
;
523 trace
.entries
= p
->addrs
;
525 metadata_access_enable();
526 save_stack_trace(&trace
);
527 metadata_access_disable();
529 /* See rant in lockdep.c */
530 if (trace
.nr_entries
!= 0 &&
531 trace
.entries
[trace
.nr_entries
- 1] == ULONG_MAX
)
534 for (i
= trace
.nr_entries
; i
< TRACK_ADDRS_COUNT
; i
++)
538 p
->cpu
= smp_processor_id();
539 p
->pid
= current
->pid
;
542 memset(p
, 0, sizeof(struct track
));
545 static void init_tracking(struct kmem_cache
*s
, void *object
)
547 if (!(s
->flags
& SLAB_STORE_USER
))
550 set_track(s
, object
, TRACK_FREE
, 0UL);
551 set_track(s
, object
, TRACK_ALLOC
, 0UL);
554 static void print_track(const char *s
, struct track
*t
)
559 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
560 s
, (void *)t
->addr
, jiffies
- t
->when
, t
->cpu
, t
->pid
);
561 #ifdef CONFIG_STACKTRACE
564 for (i
= 0; i
< TRACK_ADDRS_COUNT
; i
++)
566 pr_err("\t%pS\n", (void *)t
->addrs
[i
]);
573 static void print_tracking(struct kmem_cache
*s
, void *object
)
575 if (!(s
->flags
& SLAB_STORE_USER
))
578 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
579 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
582 static void print_page_info(struct page
*page
)
584 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
585 page
, page
->objects
, page
->inuse
, page
->freelist
, page
->flags
);
589 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
591 struct va_format vaf
;
597 pr_err("=============================================================================\n");
598 pr_err("BUG %s (%s): %pV\n", s
->name
, print_tainted(), &vaf
);
599 pr_err("-----------------------------------------------------------------------------\n\n");
601 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
605 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
607 struct va_format vaf
;
613 pr_err("FIX %s: %pV\n", s
->name
, &vaf
);
617 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
619 unsigned int off
; /* Offset of last byte */
620 u8
*addr
= page_address(page
);
622 print_tracking(s
, p
);
624 print_page_info(page
);
626 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
627 p
, p
- addr
, get_freepointer(s
, p
));
630 print_section("Bytes b4 ", p
- 16, 16);
632 print_section("Object ", p
, min_t(unsigned long, s
->object_size
,
634 if (s
->flags
& SLAB_RED_ZONE
)
635 print_section("Redzone ", p
+ s
->object_size
,
636 s
->inuse
- s
->object_size
);
639 off
= s
->offset
+ sizeof(void *);
643 if (s
->flags
& SLAB_STORE_USER
)
644 off
+= 2 * sizeof(struct track
);
647 /* Beginning of the filler is the free pointer */
648 print_section("Padding ", p
+ off
, s
->size
- off
);
653 void object_err(struct kmem_cache
*s
, struct page
*page
,
654 u8
*object
, char *reason
)
656 slab_bug(s
, "%s", reason
);
657 print_trailer(s
, page
, object
);
660 static void slab_err(struct kmem_cache
*s
, struct page
*page
,
661 const char *fmt
, ...)
667 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
669 slab_bug(s
, "%s", buf
);
670 print_page_info(page
);
674 static void init_object(struct kmem_cache
*s
, void *object
, u8 val
)
678 if (s
->flags
& __OBJECT_POISON
) {
679 memset(p
, POISON_FREE
, s
->object_size
- 1);
680 p
[s
->object_size
- 1] = POISON_END
;
683 if (s
->flags
& SLAB_RED_ZONE
)
684 memset(p
+ s
->object_size
, val
, s
->inuse
- s
->object_size
);
687 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
688 void *from
, void *to
)
690 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
691 memset(from
, data
, to
- from
);
694 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
695 u8
*object
, char *what
,
696 u8
*start
, unsigned int value
, unsigned int bytes
)
701 metadata_access_enable();
702 fault
= memchr_inv(start
, value
, bytes
);
703 metadata_access_disable();
708 while (end
> fault
&& end
[-1] == value
)
711 slab_bug(s
, "%s overwritten", what
);
712 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
713 fault
, end
- 1, fault
[0], value
);
714 print_trailer(s
, page
, object
);
716 restore_bytes(s
, what
, value
, fault
, end
);
724 * Bytes of the object to be managed.
725 * If the freepointer may overlay the object then the free
726 * pointer is the first word of the object.
728 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
731 * object + s->object_size
732 * Padding to reach word boundary. This is also used for Redzoning.
733 * Padding is extended by another word if Redzoning is enabled and
734 * object_size == inuse.
736 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
737 * 0xcc (RED_ACTIVE) for objects in use.
740 * Meta data starts here.
742 * A. Free pointer (if we cannot overwrite object on free)
743 * B. Tracking data for SLAB_STORE_USER
744 * C. Padding to reach required alignment boundary or at mininum
745 * one word if debugging is on to be able to detect writes
746 * before the word boundary.
748 * Padding is done using 0x5a (POISON_INUSE)
751 * Nothing is used beyond s->size.
753 * If slabcaches are merged then the object_size and inuse boundaries are mostly
754 * ignored. And therefore no slab options that rely on these boundaries
755 * may be used with merged slabcaches.
758 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
760 unsigned long off
= s
->inuse
; /* The end of info */
763 /* Freepointer is placed after the object. */
764 off
+= sizeof(void *);
766 if (s
->flags
& SLAB_STORE_USER
)
767 /* We also have user information there */
768 off
+= 2 * sizeof(struct track
);
773 return check_bytes_and_report(s
, page
, p
, "Object padding",
774 p
+ off
, POISON_INUSE
, s
->size
- off
);
777 /* Check the pad bytes at the end of a slab page */
778 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
786 if (!(s
->flags
& SLAB_POISON
))
789 start
= page_address(page
);
790 length
= (PAGE_SIZE
<< compound_order(page
)) - s
->reserved
;
791 end
= start
+ length
;
792 remainder
= length
% s
->size
;
796 metadata_access_enable();
797 fault
= memchr_inv(end
- remainder
, POISON_INUSE
, remainder
);
798 metadata_access_disable();
801 while (end
> fault
&& end
[-1] == POISON_INUSE
)
804 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
805 print_section("Padding ", end
- remainder
, remainder
);
807 restore_bytes(s
, "slab padding", POISON_INUSE
, end
- remainder
, end
);
811 static int check_object(struct kmem_cache
*s
, struct page
*page
,
812 void *object
, u8 val
)
815 u8
*endobject
= object
+ s
->object_size
;
817 if (s
->flags
& SLAB_RED_ZONE
) {
818 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
819 endobject
, val
, s
->inuse
- s
->object_size
))
822 if ((s
->flags
& SLAB_POISON
) && s
->object_size
< s
->inuse
) {
823 check_bytes_and_report(s
, page
, p
, "Alignment padding",
824 endobject
, POISON_INUSE
,
825 s
->inuse
- s
->object_size
);
829 if (s
->flags
& SLAB_POISON
) {
830 if (val
!= SLUB_RED_ACTIVE
&& (s
->flags
& __OBJECT_POISON
) &&
831 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
832 POISON_FREE
, s
->object_size
- 1) ||
833 !check_bytes_and_report(s
, page
, p
, "Poison",
834 p
+ s
->object_size
- 1, POISON_END
, 1)))
837 * check_pad_bytes cleans up on its own.
839 check_pad_bytes(s
, page
, p
);
842 if (!s
->offset
&& val
== SLUB_RED_ACTIVE
)
844 * Object and freepointer overlap. Cannot check
845 * freepointer while object is allocated.
849 /* Check free pointer validity */
850 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
851 object_err(s
, page
, p
, "Freepointer corrupt");
853 * No choice but to zap it and thus lose the remainder
854 * of the free objects in this slab. May cause
855 * another error because the object count is now wrong.
857 set_freepointer(s
, p
, NULL
);
863 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
867 VM_BUG_ON(!irqs_disabled());
869 if (!PageSlab(page
)) {
870 slab_err(s
, page
, "Not a valid slab page");
874 maxobj
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
875 if (page
->objects
> maxobj
) {
876 slab_err(s
, page
, "objects %u > max %u",
877 page
->objects
, maxobj
);
880 if (page
->inuse
> page
->objects
) {
881 slab_err(s
, page
, "inuse %u > max %u",
882 page
->inuse
, page
->objects
);
885 /* Slab_pad_check fixes things up after itself */
886 slab_pad_check(s
, page
);
891 * Determine if a certain object on a page is on the freelist. Must hold the
892 * slab lock to guarantee that the chains are in a consistent state.
894 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
902 while (fp
&& nr
<= page
->objects
) {
905 if (!check_valid_pointer(s
, page
, fp
)) {
907 object_err(s
, page
, object
,
908 "Freechain corrupt");
909 set_freepointer(s
, object
, NULL
);
911 slab_err(s
, page
, "Freepointer corrupt");
912 page
->freelist
= NULL
;
913 page
->inuse
= page
->objects
;
914 slab_fix(s
, "Freelist cleared");
920 fp
= get_freepointer(s
, object
);
924 max_objects
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
925 if (max_objects
> MAX_OBJS_PER_PAGE
)
926 max_objects
= MAX_OBJS_PER_PAGE
;
928 if (page
->objects
!= max_objects
) {
929 slab_err(s
, page
, "Wrong number of objects. Found %d but "
930 "should be %d", page
->objects
, max_objects
);
931 page
->objects
= max_objects
;
932 slab_fix(s
, "Number of objects adjusted.");
934 if (page
->inuse
!= page
->objects
- nr
) {
935 slab_err(s
, page
, "Wrong object count. Counter is %d but "
936 "counted were %d", page
->inuse
, page
->objects
- nr
);
937 page
->inuse
= page
->objects
- nr
;
938 slab_fix(s
, "Object count adjusted.");
940 return search
== NULL
;
943 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
,
946 if (s
->flags
& SLAB_TRACE
) {
947 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
949 alloc
? "alloc" : "free",
954 print_section("Object ", (void *)object
,
962 * Tracking of fully allocated slabs for debugging purposes.
964 static void add_full(struct kmem_cache
*s
,
965 struct kmem_cache_node
*n
, struct page
*page
)
967 if (!(s
->flags
& SLAB_STORE_USER
))
970 lockdep_assert_held(&n
->list_lock
);
971 list_add(&page
->lru
, &n
->full
);
974 static void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
, struct page
*page
)
976 if (!(s
->flags
& SLAB_STORE_USER
))
979 lockdep_assert_held(&n
->list_lock
);
980 list_del(&page
->lru
);
983 /* Tracking of the number of slabs for debugging purposes */
984 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
986 struct kmem_cache_node
*n
= get_node(s
, node
);
988 return atomic_long_read(&n
->nr_slabs
);
991 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
993 return atomic_long_read(&n
->nr_slabs
);
996 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
998 struct kmem_cache_node
*n
= get_node(s
, node
);
1001 * May be called early in order to allocate a slab for the
1002 * kmem_cache_node structure. Solve the chicken-egg
1003 * dilemma by deferring the increment of the count during
1004 * bootstrap (see early_kmem_cache_node_alloc).
1007 atomic_long_inc(&n
->nr_slabs
);
1008 atomic_long_add(objects
, &n
->total_objects
);
1011 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1013 struct kmem_cache_node
*n
= get_node(s
, node
);
1015 atomic_long_dec(&n
->nr_slabs
);
1016 atomic_long_sub(objects
, &n
->total_objects
);
1019 /* Object debug checks for alloc/free paths */
1020 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
1023 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
1026 init_object(s
, object
, SLUB_RED_INACTIVE
);
1027 init_tracking(s
, object
);
1030 static noinline
int alloc_debug_processing(struct kmem_cache
*s
,
1032 void *object
, unsigned long addr
)
1034 if (!check_slab(s
, page
))
1037 if (!check_valid_pointer(s
, page
, object
)) {
1038 object_err(s
, page
, object
, "Freelist Pointer check fails");
1042 if (!check_object(s
, page
, object
, SLUB_RED_INACTIVE
))
1045 /* Success perform special debug activities for allocs */
1046 if (s
->flags
& SLAB_STORE_USER
)
1047 set_track(s
, object
, TRACK_ALLOC
, addr
);
1048 trace(s
, page
, object
, 1);
1049 init_object(s
, object
, SLUB_RED_ACTIVE
);
1053 if (PageSlab(page
)) {
1055 * If this is a slab page then lets do the best we can
1056 * to avoid issues in the future. Marking all objects
1057 * as used avoids touching the remaining objects.
1059 slab_fix(s
, "Marking all objects used");
1060 page
->inuse
= page
->objects
;
1061 page
->freelist
= NULL
;
1066 static noinline
struct kmem_cache_node
*free_debug_processing(
1067 struct kmem_cache
*s
, struct page
*page
, void *object
,
1068 unsigned long addr
, unsigned long *flags
)
1070 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1072 spin_lock_irqsave(&n
->list_lock
, *flags
);
1075 if (!check_slab(s
, page
))
1078 if (!check_valid_pointer(s
, page
, object
)) {
1079 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
1083 if (on_freelist(s
, page
, object
)) {
1084 object_err(s
, page
, object
, "Object already free");
1088 if (!check_object(s
, page
, object
, SLUB_RED_ACTIVE
))
1091 if (unlikely(s
!= page
->slab_cache
)) {
1092 if (!PageSlab(page
)) {
1093 slab_err(s
, page
, "Attempt to free object(0x%p) "
1094 "outside of slab", object
);
1095 } else if (!page
->slab_cache
) {
1096 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1100 object_err(s
, page
, object
,
1101 "page slab pointer corrupt.");
1105 if (s
->flags
& SLAB_STORE_USER
)
1106 set_track(s
, object
, TRACK_FREE
, addr
);
1107 trace(s
, page
, object
, 0);
1108 init_object(s
, object
, SLUB_RED_INACTIVE
);
1112 * Keep node_lock to preserve integrity
1113 * until the object is actually freed
1119 spin_unlock_irqrestore(&n
->list_lock
, *flags
);
1120 slab_fix(s
, "Object at 0x%p not freed", object
);
1124 static int __init
setup_slub_debug(char *str
)
1126 slub_debug
= DEBUG_DEFAULT_FLAGS
;
1127 if (*str
++ != '=' || !*str
)
1129 * No options specified. Switch on full debugging.
1135 * No options but restriction on slabs. This means full
1136 * debugging for slabs matching a pattern.
1143 * Switch off all debugging measures.
1148 * Determine which debug features should be switched on
1150 for (; *str
&& *str
!= ','; str
++) {
1151 switch (tolower(*str
)) {
1153 slub_debug
|= SLAB_DEBUG_FREE
;
1156 slub_debug
|= SLAB_RED_ZONE
;
1159 slub_debug
|= SLAB_POISON
;
1162 slub_debug
|= SLAB_STORE_USER
;
1165 slub_debug
|= SLAB_TRACE
;
1168 slub_debug
|= SLAB_FAILSLAB
;
1172 * Avoid enabling debugging on caches if its minimum
1173 * order would increase as a result.
1175 disable_higher_order_debug
= 1;
1178 pr_err("slub_debug option '%c' unknown. skipped\n",
1185 slub_debug_slabs
= str
+ 1;
1190 __setup("slub_debug", setup_slub_debug
);
1192 unsigned long kmem_cache_flags(unsigned long object_size
,
1193 unsigned long flags
, const char *name
,
1194 void (*ctor
)(void *))
1197 * Enable debugging if selected on the kernel commandline.
1199 if (slub_debug
&& (!slub_debug_slabs
|| (name
&&
1200 !strncmp(slub_debug_slabs
, name
, strlen(slub_debug_slabs
)))))
1201 flags
|= slub_debug
;
1206 static inline void setup_object_debug(struct kmem_cache
*s
,
1207 struct page
*page
, void *object
) {}
1209 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1210 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1212 static inline struct kmem_cache_node
*free_debug_processing(
1213 struct kmem_cache
*s
, struct page
*page
, void *object
,
1214 unsigned long addr
, unsigned long *flags
) { return NULL
; }
1216 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1218 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1219 void *object
, u8 val
) { return 1; }
1220 static inline void add_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1221 struct page
*page
) {}
1222 static inline void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1223 struct page
*page
) {}
1224 unsigned long kmem_cache_flags(unsigned long object_size
,
1225 unsigned long flags
, const char *name
,
1226 void (*ctor
)(void *))
1230 #define slub_debug 0
1232 #define disable_higher_order_debug 0
1234 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1236 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1238 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
,
1240 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
,
1243 #endif /* CONFIG_SLUB_DEBUG */
1246 * Hooks for other subsystems that check memory allocations. In a typical
1247 * production configuration these hooks all should produce no code at all.
1249 static inline void kmalloc_large_node_hook(void *ptr
, size_t size
, gfp_t flags
)
1251 kmemleak_alloc(ptr
, size
, 1, flags
);
1252 kasan_kmalloc_large(ptr
, size
);
1255 static inline void kfree_hook(const void *x
)
1258 kasan_kfree_large(x
);
1261 static inline struct kmem_cache
*slab_pre_alloc_hook(struct kmem_cache
*s
,
1264 flags
&= gfp_allowed_mask
;
1265 lockdep_trace_alloc(flags
);
1266 might_sleep_if(flags
& __GFP_WAIT
);
1268 if (should_failslab(s
->object_size
, flags
, s
->flags
))
1271 return memcg_kmem_get_cache(s
, flags
);
1274 static inline void slab_post_alloc_hook(struct kmem_cache
*s
,
1275 gfp_t flags
, void *object
)
1277 flags
&= gfp_allowed_mask
;
1278 kmemcheck_slab_alloc(s
, flags
, object
, slab_ksize(s
));
1279 kmemleak_alloc_recursive(object
, s
->object_size
, 1, s
->flags
, flags
);
1280 memcg_kmem_put_cache(s
);
1281 kasan_slab_alloc(s
, object
);
1284 static inline void slab_free_hook(struct kmem_cache
*s
, void *x
)
1286 kmemleak_free_recursive(x
, s
->flags
);
1289 * Trouble is that we may no longer disable interrupts in the fast path
1290 * So in order to make the debug calls that expect irqs to be
1291 * disabled we need to disable interrupts temporarily.
1293 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1295 unsigned long flags
;
1297 local_irq_save(flags
);
1298 kmemcheck_slab_free(s
, x
, s
->object_size
);
1299 debug_check_no_locks_freed(x
, s
->object_size
);
1300 local_irq_restore(flags
);
1303 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
1304 debug_check_no_obj_freed(x
, s
->object_size
);
1306 kasan_slab_free(s
, x
);
1309 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1312 setup_object_debug(s
, page
, object
);
1313 if (unlikely(s
->ctor
)) {
1314 kasan_unpoison_object_data(s
, object
);
1316 kasan_poison_object_data(s
, object
);
1321 * Slab allocation and freeing
1323 static inline struct page
*alloc_slab_page(struct kmem_cache
*s
,
1324 gfp_t flags
, int node
, struct kmem_cache_order_objects oo
)
1327 int order
= oo_order(oo
);
1329 flags
|= __GFP_NOTRACK
;
1331 if (node
== NUMA_NO_NODE
)
1332 page
= alloc_pages(flags
, order
);
1334 page
= __alloc_pages_node(node
, flags
, order
);
1336 if (page
&& memcg_charge_slab(page
, flags
, order
, s
)) {
1337 __free_pages(page
, order
);
1344 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1347 struct kmem_cache_order_objects oo
= s
->oo
;
1352 flags
&= gfp_allowed_mask
;
1354 if (flags
& __GFP_WAIT
)
1357 flags
|= s
->allocflags
;
1360 * Let the initial higher-order allocation fail under memory pressure
1361 * so we fall-back to the minimum order allocation.
1363 alloc_gfp
= (flags
| __GFP_NOWARN
| __GFP_NORETRY
) & ~__GFP_NOFAIL
;
1364 if ((alloc_gfp
& __GFP_WAIT
) && oo_order(oo
) > oo_order(s
->min
))
1365 alloc_gfp
= (alloc_gfp
| __GFP_NOMEMALLOC
) & ~__GFP_WAIT
;
1367 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1368 if (unlikely(!page
)) {
1372 * Allocation may have failed due to fragmentation.
1373 * Try a lower order alloc if possible
1375 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1376 if (unlikely(!page
))
1378 stat(s
, ORDER_FALLBACK
);
1381 if (kmemcheck_enabled
&&
1382 !(s
->flags
& (SLAB_NOTRACK
| DEBUG_DEFAULT_FLAGS
))) {
1383 int pages
= 1 << oo_order(oo
);
1385 kmemcheck_alloc_shadow(page
, oo_order(oo
), alloc_gfp
, node
);
1388 * Objects from caches that have a constructor don't get
1389 * cleared when they're allocated, so we need to do it here.
1392 kmemcheck_mark_uninitialized_pages(page
, pages
);
1394 kmemcheck_mark_unallocated_pages(page
, pages
);
1397 page
->objects
= oo_objects(oo
);
1399 order
= compound_order(page
);
1400 page
->slab_cache
= s
;
1401 __SetPageSlab(page
);
1402 if (page_is_pfmemalloc(page
))
1403 SetPageSlabPfmemalloc(page
);
1405 start
= page_address(page
);
1407 if (unlikely(s
->flags
& SLAB_POISON
))
1408 memset(start
, POISON_INUSE
, PAGE_SIZE
<< order
);
1410 kasan_poison_slab(page
);
1412 for_each_object_idx(p
, idx
, s
, start
, page
->objects
) {
1413 setup_object(s
, page
, p
);
1414 if (likely(idx
< page
->objects
))
1415 set_freepointer(s
, p
, p
+ s
->size
);
1417 set_freepointer(s
, p
, NULL
);
1420 page
->freelist
= start
;
1421 page
->inuse
= page
->objects
;
1425 if (flags
& __GFP_WAIT
)
1426 local_irq_disable();
1430 mod_zone_page_state(page_zone(page
),
1431 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1432 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1435 inc_slabs_node(s
, page_to_nid(page
), page
->objects
);
1440 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1442 if (unlikely(flags
& GFP_SLAB_BUG_MASK
)) {
1443 pr_emerg("gfp: %u\n", flags
& GFP_SLAB_BUG_MASK
);
1447 return allocate_slab(s
,
1448 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1451 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1453 int order
= compound_order(page
);
1454 int pages
= 1 << order
;
1456 if (kmem_cache_debug(s
)) {
1459 slab_pad_check(s
, page
);
1460 for_each_object(p
, s
, page_address(page
),
1462 check_object(s
, page
, p
, SLUB_RED_INACTIVE
);
1465 kmemcheck_free_shadow(page
, compound_order(page
));
1467 mod_zone_page_state(page_zone(page
),
1468 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1469 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1472 __ClearPageSlabPfmemalloc(page
);
1473 __ClearPageSlab(page
);
1475 page_mapcount_reset(page
);
1476 if (current
->reclaim_state
)
1477 current
->reclaim_state
->reclaimed_slab
+= pages
;
1478 __free_kmem_pages(page
, order
);
1481 #define need_reserve_slab_rcu \
1482 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1484 static void rcu_free_slab(struct rcu_head
*h
)
1488 if (need_reserve_slab_rcu
)
1489 page
= virt_to_head_page(h
);
1491 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1493 __free_slab(page
->slab_cache
, page
);
1496 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1498 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1499 struct rcu_head
*head
;
1501 if (need_reserve_slab_rcu
) {
1502 int order
= compound_order(page
);
1503 int offset
= (PAGE_SIZE
<< order
) - s
->reserved
;
1505 VM_BUG_ON(s
->reserved
!= sizeof(*head
));
1506 head
= page_address(page
) + offset
;
1509 * RCU free overloads the RCU head over the LRU
1511 head
= (void *)&page
->lru
;
1514 call_rcu(head
, rcu_free_slab
);
1516 __free_slab(s
, page
);
1519 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1521 dec_slabs_node(s
, page_to_nid(page
), page
->objects
);
1526 * Management of partially allocated slabs.
1529 __add_partial(struct kmem_cache_node
*n
, struct page
*page
, int tail
)
1532 if (tail
== DEACTIVATE_TO_TAIL
)
1533 list_add_tail(&page
->lru
, &n
->partial
);
1535 list_add(&page
->lru
, &n
->partial
);
1538 static inline void add_partial(struct kmem_cache_node
*n
,
1539 struct page
*page
, int tail
)
1541 lockdep_assert_held(&n
->list_lock
);
1542 __add_partial(n
, page
, tail
);
1546 __remove_partial(struct kmem_cache_node
*n
, struct page
*page
)
1548 list_del(&page
->lru
);
1552 static inline void remove_partial(struct kmem_cache_node
*n
,
1555 lockdep_assert_held(&n
->list_lock
);
1556 __remove_partial(n
, page
);
1560 * Remove slab from the partial list, freeze it and
1561 * return the pointer to the freelist.
1563 * Returns a list of objects or NULL if it fails.
1565 static inline void *acquire_slab(struct kmem_cache
*s
,
1566 struct kmem_cache_node
*n
, struct page
*page
,
1567 int mode
, int *objects
)
1570 unsigned long counters
;
1573 lockdep_assert_held(&n
->list_lock
);
1576 * Zap the freelist and set the frozen bit.
1577 * The old freelist is the list of objects for the
1578 * per cpu allocation list.
1580 freelist
= page
->freelist
;
1581 counters
= page
->counters
;
1582 new.counters
= counters
;
1583 *objects
= new.objects
- new.inuse
;
1585 new.inuse
= page
->objects
;
1586 new.freelist
= NULL
;
1588 new.freelist
= freelist
;
1591 VM_BUG_ON(new.frozen
);
1594 if (!__cmpxchg_double_slab(s
, page
,
1596 new.freelist
, new.counters
,
1600 remove_partial(n
, page
);
1605 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
);
1606 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
);
1609 * Try to allocate a partial slab from a specific node.
1611 static void *get_partial_node(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1612 struct kmem_cache_cpu
*c
, gfp_t flags
)
1614 struct page
*page
, *page2
;
1615 void *object
= NULL
;
1620 * Racy check. If we mistakenly see no partial slabs then we
1621 * just allocate an empty slab. If we mistakenly try to get a
1622 * partial slab and there is none available then get_partials()
1625 if (!n
|| !n
->nr_partial
)
1628 spin_lock(&n
->list_lock
);
1629 list_for_each_entry_safe(page
, page2
, &n
->partial
, lru
) {
1632 if (!pfmemalloc_match(page
, flags
))
1635 t
= acquire_slab(s
, n
, page
, object
== NULL
, &objects
);
1639 available
+= objects
;
1642 stat(s
, ALLOC_FROM_PARTIAL
);
1645 put_cpu_partial(s
, page
, 0);
1646 stat(s
, CPU_PARTIAL_NODE
);
1648 if (!kmem_cache_has_cpu_partial(s
)
1649 || available
> s
->cpu_partial
/ 2)
1653 spin_unlock(&n
->list_lock
);
1658 * Get a page from somewhere. Search in increasing NUMA distances.
1660 static void *get_any_partial(struct kmem_cache
*s
, gfp_t flags
,
1661 struct kmem_cache_cpu
*c
)
1664 struct zonelist
*zonelist
;
1667 enum zone_type high_zoneidx
= gfp_zone(flags
);
1669 unsigned int cpuset_mems_cookie
;
1672 * The defrag ratio allows a configuration of the tradeoffs between
1673 * inter node defragmentation and node local allocations. A lower
1674 * defrag_ratio increases the tendency to do local allocations
1675 * instead of attempting to obtain partial slabs from other nodes.
1677 * If the defrag_ratio is set to 0 then kmalloc() always
1678 * returns node local objects. If the ratio is higher then kmalloc()
1679 * may return off node objects because partial slabs are obtained
1680 * from other nodes and filled up.
1682 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1683 * defrag_ratio = 1000) then every (well almost) allocation will
1684 * first attempt to defrag slab caches on other nodes. This means
1685 * scanning over all nodes to look for partial slabs which may be
1686 * expensive if we do it every time we are trying to find a slab
1687 * with available objects.
1689 if (!s
->remote_node_defrag_ratio
||
1690 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1694 cpuset_mems_cookie
= read_mems_allowed_begin();
1695 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
1696 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
1697 struct kmem_cache_node
*n
;
1699 n
= get_node(s
, zone_to_nid(zone
));
1701 if (n
&& cpuset_zone_allowed(zone
, flags
) &&
1702 n
->nr_partial
> s
->min_partial
) {
1703 object
= get_partial_node(s
, n
, c
, flags
);
1706 * Don't check read_mems_allowed_retry()
1707 * here - if mems_allowed was updated in
1708 * parallel, that was a harmless race
1709 * between allocation and the cpuset
1716 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1722 * Get a partial page, lock it and return it.
1724 static void *get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
,
1725 struct kmem_cache_cpu
*c
)
1728 int searchnode
= node
;
1730 if (node
== NUMA_NO_NODE
)
1731 searchnode
= numa_mem_id();
1732 else if (!node_present_pages(node
))
1733 searchnode
= node_to_mem_node(node
);
1735 object
= get_partial_node(s
, get_node(s
, searchnode
), c
, flags
);
1736 if (object
|| node
!= NUMA_NO_NODE
)
1739 return get_any_partial(s
, flags
, c
);
1742 #ifdef CONFIG_PREEMPT
1744 * Calculate the next globally unique transaction for disambiguiation
1745 * during cmpxchg. The transactions start with the cpu number and are then
1746 * incremented by CONFIG_NR_CPUS.
1748 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1751 * No preemption supported therefore also no need to check for
1757 static inline unsigned long next_tid(unsigned long tid
)
1759 return tid
+ TID_STEP
;
1762 static inline unsigned int tid_to_cpu(unsigned long tid
)
1764 return tid
% TID_STEP
;
1767 static inline unsigned long tid_to_event(unsigned long tid
)
1769 return tid
/ TID_STEP
;
1772 static inline unsigned int init_tid(int cpu
)
1777 static inline void note_cmpxchg_failure(const char *n
,
1778 const struct kmem_cache
*s
, unsigned long tid
)
1780 #ifdef SLUB_DEBUG_CMPXCHG
1781 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
1783 pr_info("%s %s: cmpxchg redo ", n
, s
->name
);
1785 #ifdef CONFIG_PREEMPT
1786 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
1787 pr_warn("due to cpu change %d -> %d\n",
1788 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
1791 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
1792 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1793 tid_to_event(tid
), tid_to_event(actual_tid
));
1795 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1796 actual_tid
, tid
, next_tid(tid
));
1798 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
1801 static void init_kmem_cache_cpus(struct kmem_cache
*s
)
1805 for_each_possible_cpu(cpu
)
1806 per_cpu_ptr(s
->cpu_slab
, cpu
)->tid
= init_tid(cpu
);
1810 * Remove the cpu slab
1812 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
,
1815 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
1816 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1818 enum slab_modes l
= M_NONE
, m
= M_NONE
;
1820 int tail
= DEACTIVATE_TO_HEAD
;
1824 if (page
->freelist
) {
1825 stat(s
, DEACTIVATE_REMOTE_FREES
);
1826 tail
= DEACTIVATE_TO_TAIL
;
1830 * Stage one: Free all available per cpu objects back
1831 * to the page freelist while it is still frozen. Leave the
1834 * There is no need to take the list->lock because the page
1837 while (freelist
&& (nextfree
= get_freepointer(s
, freelist
))) {
1839 unsigned long counters
;
1842 prior
= page
->freelist
;
1843 counters
= page
->counters
;
1844 set_freepointer(s
, freelist
, prior
);
1845 new.counters
= counters
;
1847 VM_BUG_ON(!new.frozen
);
1849 } while (!__cmpxchg_double_slab(s
, page
,
1851 freelist
, new.counters
,
1852 "drain percpu freelist"));
1854 freelist
= nextfree
;
1858 * Stage two: Ensure that the page is unfrozen while the
1859 * list presence reflects the actual number of objects
1862 * We setup the list membership and then perform a cmpxchg
1863 * with the count. If there is a mismatch then the page
1864 * is not unfrozen but the page is on the wrong list.
1866 * Then we restart the process which may have to remove
1867 * the page from the list that we just put it on again
1868 * because the number of objects in the slab may have
1873 old
.freelist
= page
->freelist
;
1874 old
.counters
= page
->counters
;
1875 VM_BUG_ON(!old
.frozen
);
1877 /* Determine target state of the slab */
1878 new.counters
= old
.counters
;
1881 set_freepointer(s
, freelist
, old
.freelist
);
1882 new.freelist
= freelist
;
1884 new.freelist
= old
.freelist
;
1888 if (!new.inuse
&& n
->nr_partial
>= s
->min_partial
)
1890 else if (new.freelist
) {
1895 * Taking the spinlock removes the possiblity
1896 * that acquire_slab() will see a slab page that
1899 spin_lock(&n
->list_lock
);
1903 if (kmem_cache_debug(s
) && !lock
) {
1906 * This also ensures that the scanning of full
1907 * slabs from diagnostic functions will not see
1910 spin_lock(&n
->list_lock
);
1918 remove_partial(n
, page
);
1920 else if (l
== M_FULL
)
1922 remove_full(s
, n
, page
);
1924 if (m
== M_PARTIAL
) {
1926 add_partial(n
, page
, tail
);
1929 } else if (m
== M_FULL
) {
1931 stat(s
, DEACTIVATE_FULL
);
1932 add_full(s
, n
, page
);
1938 if (!__cmpxchg_double_slab(s
, page
,
1939 old
.freelist
, old
.counters
,
1940 new.freelist
, new.counters
,
1945 spin_unlock(&n
->list_lock
);
1948 stat(s
, DEACTIVATE_EMPTY
);
1949 discard_slab(s
, page
);
1955 * Unfreeze all the cpu partial slabs.
1957 * This function must be called with interrupts disabled
1958 * for the cpu using c (or some other guarantee must be there
1959 * to guarantee no concurrent accesses).
1961 static void unfreeze_partials(struct kmem_cache
*s
,
1962 struct kmem_cache_cpu
*c
)
1964 #ifdef CONFIG_SLUB_CPU_PARTIAL
1965 struct kmem_cache_node
*n
= NULL
, *n2
= NULL
;
1966 struct page
*page
, *discard_page
= NULL
;
1968 while ((page
= c
->partial
)) {
1972 c
->partial
= page
->next
;
1974 n2
= get_node(s
, page_to_nid(page
));
1977 spin_unlock(&n
->list_lock
);
1980 spin_lock(&n
->list_lock
);
1985 old
.freelist
= page
->freelist
;
1986 old
.counters
= page
->counters
;
1987 VM_BUG_ON(!old
.frozen
);
1989 new.counters
= old
.counters
;
1990 new.freelist
= old
.freelist
;
1994 } while (!__cmpxchg_double_slab(s
, page
,
1995 old
.freelist
, old
.counters
,
1996 new.freelist
, new.counters
,
1997 "unfreezing slab"));
1999 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
)) {
2000 page
->next
= discard_page
;
2001 discard_page
= page
;
2003 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2004 stat(s
, FREE_ADD_PARTIAL
);
2009 spin_unlock(&n
->list_lock
);
2011 while (discard_page
) {
2012 page
= discard_page
;
2013 discard_page
= discard_page
->next
;
2015 stat(s
, DEACTIVATE_EMPTY
);
2016 discard_slab(s
, page
);
2023 * Put a page that was just frozen (in __slab_free) into a partial page
2024 * slot if available. This is done without interrupts disabled and without
2025 * preemption disabled. The cmpxchg is racy and may put the partial page
2026 * onto a random cpus partial slot.
2028 * If we did not find a slot then simply move all the partials to the
2029 * per node partial list.
2031 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
)
2033 #ifdef CONFIG_SLUB_CPU_PARTIAL
2034 struct page
*oldpage
;
2042 oldpage
= this_cpu_read(s
->cpu_slab
->partial
);
2045 pobjects
= oldpage
->pobjects
;
2046 pages
= oldpage
->pages
;
2047 if (drain
&& pobjects
> s
->cpu_partial
) {
2048 unsigned long flags
;
2050 * partial array is full. Move the existing
2051 * set to the per node partial list.
2053 local_irq_save(flags
);
2054 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2055 local_irq_restore(flags
);
2059 stat(s
, CPU_PARTIAL_DRAIN
);
2064 pobjects
+= page
->objects
- page
->inuse
;
2066 page
->pages
= pages
;
2067 page
->pobjects
= pobjects
;
2068 page
->next
= oldpage
;
2070 } while (this_cpu_cmpxchg(s
->cpu_slab
->partial
, oldpage
, page
)
2072 if (unlikely(!s
->cpu_partial
)) {
2073 unsigned long flags
;
2075 local_irq_save(flags
);
2076 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2077 local_irq_restore(flags
);
2083 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
2085 stat(s
, CPUSLAB_FLUSH
);
2086 deactivate_slab(s
, c
->page
, c
->freelist
);
2088 c
->tid
= next_tid(c
->tid
);
2096 * Called from IPI handler with interrupts disabled.
2098 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
2100 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2106 unfreeze_partials(s
, c
);
2110 static void flush_cpu_slab(void *d
)
2112 struct kmem_cache
*s
= d
;
2114 __flush_cpu_slab(s
, smp_processor_id());
2117 static bool has_cpu_slab(int cpu
, void *info
)
2119 struct kmem_cache
*s
= info
;
2120 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2122 return c
->page
|| c
->partial
;
2125 static void flush_all(struct kmem_cache
*s
)
2127 on_each_cpu_cond(has_cpu_slab
, flush_cpu_slab
, s
, 1, GFP_ATOMIC
);
2131 * Check if the objects in a per cpu structure fit numa
2132 * locality expectations.
2134 static inline int node_match(struct page
*page
, int node
)
2137 if (!page
|| (node
!= NUMA_NO_NODE
&& page_to_nid(page
) != node
))
2143 #ifdef CONFIG_SLUB_DEBUG
2144 static int count_free(struct page
*page
)
2146 return page
->objects
- page
->inuse
;
2149 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
2151 return atomic_long_read(&n
->total_objects
);
2153 #endif /* CONFIG_SLUB_DEBUG */
2155 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2156 static unsigned long count_partial(struct kmem_cache_node
*n
,
2157 int (*get_count
)(struct page
*))
2159 unsigned long flags
;
2160 unsigned long x
= 0;
2163 spin_lock_irqsave(&n
->list_lock
, flags
);
2164 list_for_each_entry(page
, &n
->partial
, lru
)
2165 x
+= get_count(page
);
2166 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2169 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2171 static noinline
void
2172 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
2174 #ifdef CONFIG_SLUB_DEBUG
2175 static DEFINE_RATELIMIT_STATE(slub_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2176 DEFAULT_RATELIMIT_BURST
);
2178 struct kmem_cache_node
*n
;
2180 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slub_oom_rs
))
2183 pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2185 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2186 s
->name
, s
->object_size
, s
->size
, oo_order(s
->oo
),
2189 if (oo_order(s
->min
) > get_order(s
->object_size
))
2190 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2193 for_each_kmem_cache_node(s
, node
, n
) {
2194 unsigned long nr_slabs
;
2195 unsigned long nr_objs
;
2196 unsigned long nr_free
;
2198 nr_free
= count_partial(n
, count_free
);
2199 nr_slabs
= node_nr_slabs(n
);
2200 nr_objs
= node_nr_objs(n
);
2202 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2203 node
, nr_slabs
, nr_objs
, nr_free
);
2208 static inline void *new_slab_objects(struct kmem_cache
*s
, gfp_t flags
,
2209 int node
, struct kmem_cache_cpu
**pc
)
2212 struct kmem_cache_cpu
*c
= *pc
;
2215 freelist
= get_partial(s
, flags
, node
, c
);
2220 page
= new_slab(s
, flags
, node
);
2222 c
= raw_cpu_ptr(s
->cpu_slab
);
2227 * No other reference to the page yet so we can
2228 * muck around with it freely without cmpxchg
2230 freelist
= page
->freelist
;
2231 page
->freelist
= NULL
;
2233 stat(s
, ALLOC_SLAB
);
2242 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
)
2244 if (unlikely(PageSlabPfmemalloc(page
)))
2245 return gfp_pfmemalloc_allowed(gfpflags
);
2251 * Check the page->freelist of a page and either transfer the freelist to the
2252 * per cpu freelist or deactivate the page.
2254 * The page is still frozen if the return value is not NULL.
2256 * If this function returns NULL then the page has been unfrozen.
2258 * This function must be called with interrupt disabled.
2260 static inline void *get_freelist(struct kmem_cache
*s
, struct page
*page
)
2263 unsigned long counters
;
2267 freelist
= page
->freelist
;
2268 counters
= page
->counters
;
2270 new.counters
= counters
;
2271 VM_BUG_ON(!new.frozen
);
2273 new.inuse
= page
->objects
;
2274 new.frozen
= freelist
!= NULL
;
2276 } while (!__cmpxchg_double_slab(s
, page
,
2285 * Slow path. The lockless freelist is empty or we need to perform
2288 * Processing is still very fast if new objects have been freed to the
2289 * regular freelist. In that case we simply take over the regular freelist
2290 * as the lockless freelist and zap the regular freelist.
2292 * If that is not working then we fall back to the partial lists. We take the
2293 * first element of the freelist as the object to allocate now and move the
2294 * rest of the freelist to the lockless freelist.
2296 * And if we were unable to get a new slab from the partial slab lists then
2297 * we need to allocate a new slab. This is the slowest path since it involves
2298 * a call to the page allocator and the setup of a new slab.
2300 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2301 unsigned long addr
, struct kmem_cache_cpu
*c
)
2305 unsigned long flags
;
2307 local_irq_save(flags
);
2308 #ifdef CONFIG_PREEMPT
2310 * We may have been preempted and rescheduled on a different
2311 * cpu before disabling interrupts. Need to reload cpu area
2314 c
= this_cpu_ptr(s
->cpu_slab
);
2322 if (unlikely(!node_match(page
, node
))) {
2323 int searchnode
= node
;
2325 if (node
!= NUMA_NO_NODE
&& !node_present_pages(node
))
2326 searchnode
= node_to_mem_node(node
);
2328 if (unlikely(!node_match(page
, searchnode
))) {
2329 stat(s
, ALLOC_NODE_MISMATCH
);
2330 deactivate_slab(s
, page
, c
->freelist
);
2338 * By rights, we should be searching for a slab page that was
2339 * PFMEMALLOC but right now, we are losing the pfmemalloc
2340 * information when the page leaves the per-cpu allocator
2342 if (unlikely(!pfmemalloc_match(page
, gfpflags
))) {
2343 deactivate_slab(s
, page
, c
->freelist
);
2349 /* must check again c->freelist in case of cpu migration or IRQ */
2350 freelist
= c
->freelist
;
2354 freelist
= get_freelist(s
, page
);
2358 stat(s
, DEACTIVATE_BYPASS
);
2362 stat(s
, ALLOC_REFILL
);
2366 * freelist is pointing to the list of objects to be used.
2367 * page is pointing to the page from which the objects are obtained.
2368 * That page must be frozen for per cpu allocations to work.
2370 VM_BUG_ON(!c
->page
->frozen
);
2371 c
->freelist
= get_freepointer(s
, freelist
);
2372 c
->tid
= next_tid(c
->tid
);
2373 local_irq_restore(flags
);
2379 page
= c
->page
= c
->partial
;
2380 c
->partial
= page
->next
;
2381 stat(s
, CPU_PARTIAL_ALLOC
);
2386 freelist
= new_slab_objects(s
, gfpflags
, node
, &c
);
2388 if (unlikely(!freelist
)) {
2389 slab_out_of_memory(s
, gfpflags
, node
);
2390 local_irq_restore(flags
);
2395 if (likely(!kmem_cache_debug(s
) && pfmemalloc_match(page
, gfpflags
)))
2398 /* Only entered in the debug case */
2399 if (kmem_cache_debug(s
) &&
2400 !alloc_debug_processing(s
, page
, freelist
, addr
))
2401 goto new_slab
; /* Slab failed checks. Next slab needed */
2403 deactivate_slab(s
, page
, get_freepointer(s
, freelist
));
2406 local_irq_restore(flags
);
2411 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2412 * have the fastpath folded into their functions. So no function call
2413 * overhead for requests that can be satisfied on the fastpath.
2415 * The fastpath works by first checking if the lockless freelist can be used.
2416 * If not then __slab_alloc is called for slow processing.
2418 * Otherwise we can simply pick the next object from the lockless free list.
2420 static __always_inline
void *slab_alloc_node(struct kmem_cache
*s
,
2421 gfp_t gfpflags
, int node
, unsigned long addr
)
2424 struct kmem_cache_cpu
*c
;
2428 s
= slab_pre_alloc_hook(s
, gfpflags
);
2433 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2434 * enabled. We may switch back and forth between cpus while
2435 * reading from one cpu area. That does not matter as long
2436 * as we end up on the original cpu again when doing the cmpxchg.
2438 * We should guarantee that tid and kmem_cache are retrieved on
2439 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2440 * to check if it is matched or not.
2443 tid
= this_cpu_read(s
->cpu_slab
->tid
);
2444 c
= raw_cpu_ptr(s
->cpu_slab
);
2445 } while (IS_ENABLED(CONFIG_PREEMPT
) &&
2446 unlikely(tid
!= READ_ONCE(c
->tid
)));
2449 * Irqless object alloc/free algorithm used here depends on sequence
2450 * of fetching cpu_slab's data. tid should be fetched before anything
2451 * on c to guarantee that object and page associated with previous tid
2452 * won't be used with current tid. If we fetch tid first, object and
2453 * page could be one associated with next tid and our alloc/free
2454 * request will be failed. In this case, we will retry. So, no problem.
2459 * The transaction ids are globally unique per cpu and per operation on
2460 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2461 * occurs on the right processor and that there was no operation on the
2462 * linked list in between.
2465 object
= c
->freelist
;
2467 if (unlikely(!object
|| !node_match(page
, node
))) {
2468 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
2469 stat(s
, ALLOC_SLOWPATH
);
2471 void *next_object
= get_freepointer_safe(s
, object
);
2474 * The cmpxchg will only match if there was no additional
2475 * operation and if we are on the right processor.
2477 * The cmpxchg does the following atomically (without lock
2479 * 1. Relocate first pointer to the current per cpu area.
2480 * 2. Verify that tid and freelist have not been changed
2481 * 3. If they were not changed replace tid and freelist
2483 * Since this is without lock semantics the protection is only
2484 * against code executing on this cpu *not* from access by
2487 if (unlikely(!this_cpu_cmpxchg_double(
2488 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2490 next_object
, next_tid(tid
)))) {
2492 note_cmpxchg_failure("slab_alloc", s
, tid
);
2495 prefetch_freepointer(s
, next_object
);
2496 stat(s
, ALLOC_FASTPATH
);
2499 if (unlikely(gfpflags
& __GFP_ZERO
) && object
)
2500 memset(object
, 0, s
->object_size
);
2502 slab_post_alloc_hook(s
, gfpflags
, object
);
2507 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
2508 gfp_t gfpflags
, unsigned long addr
)
2510 return slab_alloc_node(s
, gfpflags
, NUMA_NO_NODE
, addr
);
2513 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
2515 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2517 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->object_size
,
2522 EXPORT_SYMBOL(kmem_cache_alloc
);
2524 #ifdef CONFIG_TRACING
2525 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
2527 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2528 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
2529 kasan_kmalloc(s
, ret
, size
);
2532 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
2536 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
2538 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2540 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
2541 s
->object_size
, s
->size
, gfpflags
, node
);
2545 EXPORT_SYMBOL(kmem_cache_alloc_node
);
2547 #ifdef CONFIG_TRACING
2548 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
2550 int node
, size_t size
)
2552 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2554 trace_kmalloc_node(_RET_IP_
, ret
,
2555 size
, s
->size
, gfpflags
, node
);
2557 kasan_kmalloc(s
, ret
, size
);
2560 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
2565 * Slow path handling. This may still be called frequently since objects
2566 * have a longer lifetime than the cpu slabs in most processing loads.
2568 * So we still attempt to reduce cache line usage. Just take the slab
2569 * lock and free the item. If there is no additional partial page
2570 * handling required then we can return immediately.
2572 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
2573 void *x
, unsigned long addr
)
2576 void **object
= (void *)x
;
2579 unsigned long counters
;
2580 struct kmem_cache_node
*n
= NULL
;
2581 unsigned long uninitialized_var(flags
);
2583 stat(s
, FREE_SLOWPATH
);
2585 if (kmem_cache_debug(s
) &&
2586 !(n
= free_debug_processing(s
, page
, x
, addr
, &flags
)))
2591 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2594 prior
= page
->freelist
;
2595 counters
= page
->counters
;
2596 set_freepointer(s
, object
, prior
);
2597 new.counters
= counters
;
2598 was_frozen
= new.frozen
;
2600 if ((!new.inuse
|| !prior
) && !was_frozen
) {
2602 if (kmem_cache_has_cpu_partial(s
) && !prior
) {
2605 * Slab was on no list before and will be
2607 * We can defer the list move and instead
2612 } else { /* Needs to be taken off a list */
2614 n
= get_node(s
, page_to_nid(page
));
2616 * Speculatively acquire the list_lock.
2617 * If the cmpxchg does not succeed then we may
2618 * drop the list_lock without any processing.
2620 * Otherwise the list_lock will synchronize with
2621 * other processors updating the list of slabs.
2623 spin_lock_irqsave(&n
->list_lock
, flags
);
2628 } while (!cmpxchg_double_slab(s
, page
,
2630 object
, new.counters
,
2636 * If we just froze the page then put it onto the
2637 * per cpu partial list.
2639 if (new.frozen
&& !was_frozen
) {
2640 put_cpu_partial(s
, page
, 1);
2641 stat(s
, CPU_PARTIAL_FREE
);
2644 * The list lock was not taken therefore no list
2645 * activity can be necessary.
2648 stat(s
, FREE_FROZEN
);
2652 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
))
2656 * Objects left in the slab. If it was not on the partial list before
2659 if (!kmem_cache_has_cpu_partial(s
) && unlikely(!prior
)) {
2660 if (kmem_cache_debug(s
))
2661 remove_full(s
, n
, page
);
2662 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2663 stat(s
, FREE_ADD_PARTIAL
);
2665 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2671 * Slab on the partial list.
2673 remove_partial(n
, page
);
2674 stat(s
, FREE_REMOVE_PARTIAL
);
2676 /* Slab must be on the full list */
2677 remove_full(s
, n
, page
);
2680 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2682 discard_slab(s
, page
);
2686 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2687 * can perform fastpath freeing without additional function calls.
2689 * The fastpath is only possible if we are freeing to the current cpu slab
2690 * of this processor. This typically the case if we have just allocated
2693 * If fastpath is not possible then fall back to __slab_free where we deal
2694 * with all sorts of special processing.
2696 static __always_inline
void slab_free(struct kmem_cache
*s
,
2697 struct page
*page
, void *x
, unsigned long addr
)
2699 void **object
= (void *)x
;
2700 struct kmem_cache_cpu
*c
;
2703 slab_free_hook(s
, x
);
2707 * Determine the currently cpus per cpu slab.
2708 * The cpu may change afterward. However that does not matter since
2709 * data is retrieved via this pointer. If we are on the same cpu
2710 * during the cmpxchg then the free will succeed.
2713 tid
= this_cpu_read(s
->cpu_slab
->tid
);
2714 c
= raw_cpu_ptr(s
->cpu_slab
);
2715 } while (IS_ENABLED(CONFIG_PREEMPT
) &&
2716 unlikely(tid
!= READ_ONCE(c
->tid
)));
2718 /* Same with comment on barrier() in slab_alloc_node() */
2721 if (likely(page
== c
->page
)) {
2722 set_freepointer(s
, object
, c
->freelist
);
2724 if (unlikely(!this_cpu_cmpxchg_double(
2725 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2727 object
, next_tid(tid
)))) {
2729 note_cmpxchg_failure("slab_free", s
, tid
);
2732 stat(s
, FREE_FASTPATH
);
2734 __slab_free(s
, page
, x
, addr
);
2738 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
2740 s
= cache_from_obj(s
, x
);
2743 slab_free(s
, virt_to_head_page(x
), x
, _RET_IP_
);
2744 trace_kmem_cache_free(_RET_IP_
, x
);
2746 EXPORT_SYMBOL(kmem_cache_free
);
2748 /* Note that interrupts must be enabled when calling this function. */
2749 void kmem_cache_free_bulk(struct kmem_cache
*s
, size_t size
, void **p
)
2751 struct kmem_cache_cpu
*c
;
2755 local_irq_disable();
2756 c
= this_cpu_ptr(s
->cpu_slab
);
2758 for (i
= 0; i
< size
; i
++) {
2759 void *object
= p
[i
];
2762 /* kmem cache debug support */
2763 s
= cache_from_obj(s
, object
);
2766 slab_free_hook(s
, object
);
2768 page
= virt_to_head_page(object
);
2770 if (c
->page
== page
) {
2771 /* Fastpath: local CPU free */
2772 set_freepointer(s
, object
, c
->freelist
);
2773 c
->freelist
= object
;
2775 c
->tid
= next_tid(c
->tid
);
2777 /* Slowpath: overhead locked cmpxchg_double_slab */
2778 __slab_free(s
, page
, object
, _RET_IP_
);
2779 local_irq_disable();
2780 c
= this_cpu_ptr(s
->cpu_slab
);
2784 c
->tid
= next_tid(c
->tid
);
2787 EXPORT_SYMBOL(kmem_cache_free_bulk
);
2789 /* Note that interrupts must be enabled when calling this function. */
2790 bool kmem_cache_alloc_bulk(struct kmem_cache
*s
, gfp_t flags
, size_t size
,
2793 struct kmem_cache_cpu
*c
;
2797 * Drain objects in the per cpu slab, while disabling local
2798 * IRQs, which protects against PREEMPT and interrupts
2799 * handlers invoking normal fastpath.
2801 local_irq_disable();
2802 c
= this_cpu_ptr(s
->cpu_slab
);
2804 for (i
= 0; i
< size
; i
++) {
2805 void *object
= c
->freelist
;
2807 if (unlikely(!object
)) {
2810 * Invoking slow path likely have side-effect
2811 * of re-populating per CPU c->freelist
2813 p
[i
] = __slab_alloc(s
, flags
, NUMA_NO_NODE
,
2815 if (unlikely(!p
[i
])) {
2816 __kmem_cache_free_bulk(s
, i
, p
);
2819 local_irq_disable();
2820 c
= this_cpu_ptr(s
->cpu_slab
);
2821 continue; /* goto for-loop */
2824 /* kmem_cache debug support */
2825 s
= slab_pre_alloc_hook(s
, flags
);
2827 __kmem_cache_free_bulk(s
, i
, p
);
2828 c
->tid
= next_tid(c
->tid
);
2833 c
->freelist
= get_freepointer(s
, object
);
2836 /* kmem_cache debug support */
2837 slab_post_alloc_hook(s
, flags
, object
);
2839 c
->tid
= next_tid(c
->tid
);
2842 /* Clear memory outside IRQ disabled fastpath loop */
2843 if (unlikely(flags
& __GFP_ZERO
)) {
2846 for (j
= 0; j
< i
; j
++)
2847 memset(p
[j
], 0, s
->object_size
);
2852 EXPORT_SYMBOL(kmem_cache_alloc_bulk
);
2856 * Object placement in a slab is made very easy because we always start at
2857 * offset 0. If we tune the size of the object to the alignment then we can
2858 * get the required alignment by putting one properly sized object after
2861 * Notice that the allocation order determines the sizes of the per cpu
2862 * caches. Each processor has always one slab available for allocations.
2863 * Increasing the allocation order reduces the number of times that slabs
2864 * must be moved on and off the partial lists and is therefore a factor in
2869 * Mininum / Maximum order of slab pages. This influences locking overhead
2870 * and slab fragmentation. A higher order reduces the number of partial slabs
2871 * and increases the number of allocations possible without having to
2872 * take the list_lock.
2874 static int slub_min_order
;
2875 static int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
2876 static int slub_min_objects
;
2879 * Calculate the order of allocation given an slab object size.
2881 * The order of allocation has significant impact on performance and other
2882 * system components. Generally order 0 allocations should be preferred since
2883 * order 0 does not cause fragmentation in the page allocator. Larger objects
2884 * be problematic to put into order 0 slabs because there may be too much
2885 * unused space left. We go to a higher order if more than 1/16th of the slab
2888 * In order to reach satisfactory performance we must ensure that a minimum
2889 * number of objects is in one slab. Otherwise we may generate too much
2890 * activity on the partial lists which requires taking the list_lock. This is
2891 * less a concern for large slabs though which are rarely used.
2893 * slub_max_order specifies the order where we begin to stop considering the
2894 * number of objects in a slab as critical. If we reach slub_max_order then
2895 * we try to keep the page order as low as possible. So we accept more waste
2896 * of space in favor of a small page order.
2898 * Higher order allocations also allow the placement of more objects in a
2899 * slab and thereby reduce object handling overhead. If the user has
2900 * requested a higher mininum order then we start with that one instead of
2901 * the smallest order which will fit the object.
2903 static inline int slab_order(int size
, int min_objects
,
2904 int max_order
, int fract_leftover
, int reserved
)
2908 int min_order
= slub_min_order
;
2910 if (order_objects(min_order
, size
, reserved
) > MAX_OBJS_PER_PAGE
)
2911 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
2913 for (order
= max(min_order
, get_order(min_objects
* size
+ reserved
));
2914 order
<= max_order
; order
++) {
2916 unsigned long slab_size
= PAGE_SIZE
<< order
;
2918 rem
= (slab_size
- reserved
) % size
;
2920 if (rem
<= slab_size
/ fract_leftover
)
2927 static inline int calculate_order(int size
, int reserved
)
2935 * Attempt to find best configuration for a slab. This
2936 * works by first attempting to generate a layout with
2937 * the best configuration and backing off gradually.
2939 * First we increase the acceptable waste in a slab. Then
2940 * we reduce the minimum objects required in a slab.
2942 min_objects
= slub_min_objects
;
2944 min_objects
= 4 * (fls(nr_cpu_ids
) + 1);
2945 max_objects
= order_objects(slub_max_order
, size
, reserved
);
2946 min_objects
= min(min_objects
, max_objects
);
2948 while (min_objects
> 1) {
2950 while (fraction
>= 4) {
2951 order
= slab_order(size
, min_objects
,
2952 slub_max_order
, fraction
, reserved
);
2953 if (order
<= slub_max_order
)
2961 * We were unable to place multiple objects in a slab. Now
2962 * lets see if we can place a single object there.
2964 order
= slab_order(size
, 1, slub_max_order
, 1, reserved
);
2965 if (order
<= slub_max_order
)
2969 * Doh this slab cannot be placed using slub_max_order.
2971 order
= slab_order(size
, 1, MAX_ORDER
, 1, reserved
);
2972 if (order
< MAX_ORDER
)
2978 init_kmem_cache_node(struct kmem_cache_node
*n
)
2981 spin_lock_init(&n
->list_lock
);
2982 INIT_LIST_HEAD(&n
->partial
);
2983 #ifdef CONFIG_SLUB_DEBUG
2984 atomic_long_set(&n
->nr_slabs
, 0);
2985 atomic_long_set(&n
->total_objects
, 0);
2986 INIT_LIST_HEAD(&n
->full
);
2990 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
2992 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
2993 KMALLOC_SHIFT_HIGH
* sizeof(struct kmem_cache_cpu
));
2996 * Must align to double word boundary for the double cmpxchg
2997 * instructions to work; see __pcpu_double_call_return_bool().
2999 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
3000 2 * sizeof(void *));
3005 init_kmem_cache_cpus(s
);
3010 static struct kmem_cache
*kmem_cache_node
;
3013 * No kmalloc_node yet so do it by hand. We know that this is the first
3014 * slab on the node for this slabcache. There are no concurrent accesses
3017 * Note that this function only works on the kmem_cache_node
3018 * when allocating for the kmem_cache_node. This is used for bootstrapping
3019 * memory on a fresh node that has no slab structures yet.
3021 static void early_kmem_cache_node_alloc(int node
)
3024 struct kmem_cache_node
*n
;
3026 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
3028 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
3031 if (page_to_nid(page
) != node
) {
3032 pr_err("SLUB: Unable to allocate memory from node %d\n", node
);
3033 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3038 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
3041 kmem_cache_node
->node
[node
] = n
;
3042 #ifdef CONFIG_SLUB_DEBUG
3043 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
3044 init_tracking(kmem_cache_node
, n
);
3046 kasan_kmalloc(kmem_cache_node
, n
, sizeof(struct kmem_cache_node
));
3047 init_kmem_cache_node(n
);
3048 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
3051 * No locks need to be taken here as it has just been
3052 * initialized and there is no concurrent access.
3054 __add_partial(n
, page
, DEACTIVATE_TO_HEAD
);
3057 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
3060 struct kmem_cache_node
*n
;
3062 for_each_kmem_cache_node(s
, node
, n
) {
3063 kmem_cache_free(kmem_cache_node
, n
);
3064 s
->node
[node
] = NULL
;
3068 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
3072 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3073 struct kmem_cache_node
*n
;
3075 if (slab_state
== DOWN
) {
3076 early_kmem_cache_node_alloc(node
);
3079 n
= kmem_cache_alloc_node(kmem_cache_node
,
3083 free_kmem_cache_nodes(s
);
3088 init_kmem_cache_node(n
);
3093 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
3095 if (min
< MIN_PARTIAL
)
3097 else if (min
> MAX_PARTIAL
)
3099 s
->min_partial
= min
;
3103 * calculate_sizes() determines the order and the distribution of data within
3106 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
3108 unsigned long flags
= s
->flags
;
3109 unsigned long size
= s
->object_size
;
3113 * Round up object size to the next word boundary. We can only
3114 * place the free pointer at word boundaries and this determines
3115 * the possible location of the free pointer.
3117 size
= ALIGN(size
, sizeof(void *));
3119 #ifdef CONFIG_SLUB_DEBUG
3121 * Determine if we can poison the object itself. If the user of
3122 * the slab may touch the object after free or before allocation
3123 * then we should never poison the object itself.
3125 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
3127 s
->flags
|= __OBJECT_POISON
;
3129 s
->flags
&= ~__OBJECT_POISON
;
3133 * If we are Redzoning then check if there is some space between the
3134 * end of the object and the free pointer. If not then add an
3135 * additional word to have some bytes to store Redzone information.
3137 if ((flags
& SLAB_RED_ZONE
) && size
== s
->object_size
)
3138 size
+= sizeof(void *);
3142 * With that we have determined the number of bytes in actual use
3143 * by the object. This is the potential offset to the free pointer.
3147 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
3150 * Relocate free pointer after the object if it is not
3151 * permitted to overwrite the first word of the object on
3154 * This is the case if we do RCU, have a constructor or
3155 * destructor or are poisoning the objects.
3158 size
+= sizeof(void *);
3161 #ifdef CONFIG_SLUB_DEBUG
3162 if (flags
& SLAB_STORE_USER
)
3164 * Need to store information about allocs and frees after
3167 size
+= 2 * sizeof(struct track
);
3169 if (flags
& SLAB_RED_ZONE
)
3171 * Add some empty padding so that we can catch
3172 * overwrites from earlier objects rather than let
3173 * tracking information or the free pointer be
3174 * corrupted if a user writes before the start
3177 size
+= sizeof(void *);
3181 * SLUB stores one object immediately after another beginning from
3182 * offset 0. In order to align the objects we have to simply size
3183 * each object to conform to the alignment.
3185 size
= ALIGN(size
, s
->align
);
3187 if (forced_order
>= 0)
3188 order
= forced_order
;
3190 order
= calculate_order(size
, s
->reserved
);
3197 s
->allocflags
|= __GFP_COMP
;
3199 if (s
->flags
& SLAB_CACHE_DMA
)
3200 s
->allocflags
|= GFP_DMA
;
3202 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3203 s
->allocflags
|= __GFP_RECLAIMABLE
;
3206 * Determine the number of objects per slab
3208 s
->oo
= oo_make(order
, size
, s
->reserved
);
3209 s
->min
= oo_make(get_order(size
), size
, s
->reserved
);
3210 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
3213 return !!oo_objects(s
->oo
);
3216 static int kmem_cache_open(struct kmem_cache
*s
, unsigned long flags
)
3218 s
->flags
= kmem_cache_flags(s
->size
, flags
, s
->name
, s
->ctor
);
3221 if (need_reserve_slab_rcu
&& (s
->flags
& SLAB_DESTROY_BY_RCU
))
3222 s
->reserved
= sizeof(struct rcu_head
);
3224 if (!calculate_sizes(s
, -1))
3226 if (disable_higher_order_debug
) {
3228 * Disable debugging flags that store metadata if the min slab
3231 if (get_order(s
->size
) > get_order(s
->object_size
)) {
3232 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
3234 if (!calculate_sizes(s
, -1))
3239 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3240 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3241 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_DEBUG_FLAGS
) == 0)
3242 /* Enable fast mode */
3243 s
->flags
|= __CMPXCHG_DOUBLE
;
3247 * The larger the object size is, the more pages we want on the partial
3248 * list to avoid pounding the page allocator excessively.
3250 set_min_partial(s
, ilog2(s
->size
) / 2);
3253 * cpu_partial determined the maximum number of objects kept in the
3254 * per cpu partial lists of a processor.
3256 * Per cpu partial lists mainly contain slabs that just have one
3257 * object freed. If they are used for allocation then they can be
3258 * filled up again with minimal effort. The slab will never hit the
3259 * per node partial lists and therefore no locking will be required.
3261 * This setting also determines
3263 * A) The number of objects from per cpu partial slabs dumped to the
3264 * per node list when we reach the limit.
3265 * B) The number of objects in cpu partial slabs to extract from the
3266 * per node list when we run out of per cpu objects. We only fetch
3267 * 50% to keep some capacity around for frees.
3269 if (!kmem_cache_has_cpu_partial(s
))
3271 else if (s
->size
>= PAGE_SIZE
)
3273 else if (s
->size
>= 1024)
3275 else if (s
->size
>= 256)
3276 s
->cpu_partial
= 13;
3278 s
->cpu_partial
= 30;
3281 s
->remote_node_defrag_ratio
= 1000;
3283 if (!init_kmem_cache_nodes(s
))
3286 if (alloc_kmem_cache_cpus(s
))
3289 free_kmem_cache_nodes(s
);
3291 if (flags
& SLAB_PANIC
)
3292 panic("Cannot create slab %s size=%lu realsize=%u "
3293 "order=%u offset=%u flags=%lx\n",
3294 s
->name
, (unsigned long)s
->size
, s
->size
,
3295 oo_order(s
->oo
), s
->offset
, flags
);
3299 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
3302 #ifdef CONFIG_SLUB_DEBUG
3303 void *addr
= page_address(page
);
3305 unsigned long *map
= kzalloc(BITS_TO_LONGS(page
->objects
) *
3306 sizeof(long), GFP_ATOMIC
);
3309 slab_err(s
, page
, text
, s
->name
);
3312 get_map(s
, page
, map
);
3313 for_each_object(p
, s
, addr
, page
->objects
) {
3315 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
3316 pr_err("INFO: Object 0x%p @offset=%tu\n", p
, p
- addr
);
3317 print_tracking(s
, p
);
3326 * Attempt to free all partial slabs on a node.
3327 * This is called from kmem_cache_close(). We must be the last thread
3328 * using the cache and therefore we do not need to lock anymore.
3330 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
3332 struct page
*page
, *h
;
3334 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
3336 __remove_partial(n
, page
);
3337 discard_slab(s
, page
);
3339 list_slab_objects(s
, page
,
3340 "Objects remaining in %s on kmem_cache_close()");
3346 * Release all resources used by a slab cache.
3348 static inline int kmem_cache_close(struct kmem_cache
*s
)
3351 struct kmem_cache_node
*n
;
3354 /* Attempt to free all objects */
3355 for_each_kmem_cache_node(s
, node
, n
) {
3357 if (n
->nr_partial
|| slabs_node(s
, node
))
3360 free_percpu(s
->cpu_slab
);
3361 free_kmem_cache_nodes(s
);
3365 int __kmem_cache_shutdown(struct kmem_cache
*s
)
3367 return kmem_cache_close(s
);
3370 /********************************************************************
3372 *******************************************************************/
3374 static int __init
setup_slub_min_order(char *str
)
3376 get_option(&str
, &slub_min_order
);
3381 __setup("slub_min_order=", setup_slub_min_order
);
3383 static int __init
setup_slub_max_order(char *str
)
3385 get_option(&str
, &slub_max_order
);
3386 slub_max_order
= min(slub_max_order
, MAX_ORDER
- 1);
3391 __setup("slub_max_order=", setup_slub_max_order
);
3393 static int __init
setup_slub_min_objects(char *str
)
3395 get_option(&str
, &slub_min_objects
);
3400 __setup("slub_min_objects=", setup_slub_min_objects
);
3402 void *__kmalloc(size_t size
, gfp_t flags
)
3404 struct kmem_cache
*s
;
3407 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3408 return kmalloc_large(size
, flags
);
3410 s
= kmalloc_slab(size
, flags
);
3412 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3415 ret
= slab_alloc(s
, flags
, _RET_IP_
);
3417 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
3419 kasan_kmalloc(s
, ret
, size
);
3423 EXPORT_SYMBOL(__kmalloc
);
3426 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
3431 flags
|= __GFP_COMP
| __GFP_NOTRACK
;
3432 page
= alloc_kmem_pages_node(node
, flags
, get_order(size
));
3434 ptr
= page_address(page
);
3436 kmalloc_large_node_hook(ptr
, size
, flags
);
3440 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3442 struct kmem_cache
*s
;
3445 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3446 ret
= kmalloc_large_node(size
, flags
, node
);
3448 trace_kmalloc_node(_RET_IP_
, ret
,
3449 size
, PAGE_SIZE
<< get_order(size
),
3455 s
= kmalloc_slab(size
, flags
);
3457 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3460 ret
= slab_alloc_node(s
, flags
, node
, _RET_IP_
);
3462 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
3464 kasan_kmalloc(s
, ret
, size
);
3468 EXPORT_SYMBOL(__kmalloc_node
);
3471 static size_t __ksize(const void *object
)
3475 if (unlikely(object
== ZERO_SIZE_PTR
))
3478 page
= virt_to_head_page(object
);
3480 if (unlikely(!PageSlab(page
))) {
3481 WARN_ON(!PageCompound(page
));
3482 return PAGE_SIZE
<< compound_order(page
);
3485 return slab_ksize(page
->slab_cache
);
3488 size_t ksize(const void *object
)
3490 size_t size
= __ksize(object
);
3491 /* We assume that ksize callers could use whole allocated area,
3492 so we need unpoison this area. */
3493 kasan_krealloc(object
, size
);
3496 EXPORT_SYMBOL(ksize
);
3498 void kfree(const void *x
)
3501 void *object
= (void *)x
;
3503 trace_kfree(_RET_IP_
, x
);
3505 if (unlikely(ZERO_OR_NULL_PTR(x
)))
3508 page
= virt_to_head_page(x
);
3509 if (unlikely(!PageSlab(page
))) {
3510 BUG_ON(!PageCompound(page
));
3512 __free_kmem_pages(page
, compound_order(page
));
3515 slab_free(page
->slab_cache
, page
, object
, _RET_IP_
);
3517 EXPORT_SYMBOL(kfree
);
3519 #define SHRINK_PROMOTE_MAX 32
3522 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3523 * up most to the head of the partial lists. New allocations will then
3524 * fill those up and thus they can be removed from the partial lists.
3526 * The slabs with the least items are placed last. This results in them
3527 * being allocated from last increasing the chance that the last objects
3528 * are freed in them.
3530 int __kmem_cache_shrink(struct kmem_cache
*s
, bool deactivate
)
3534 struct kmem_cache_node
*n
;
3537 struct list_head discard
;
3538 struct list_head promote
[SHRINK_PROMOTE_MAX
];
3539 unsigned long flags
;
3544 * Disable empty slabs caching. Used to avoid pinning offline
3545 * memory cgroups by kmem pages that can be freed.
3551 * s->cpu_partial is checked locklessly (see put_cpu_partial),
3552 * so we have to make sure the change is visible.
3554 kick_all_cpus_sync();
3558 for_each_kmem_cache_node(s
, node
, n
) {
3559 INIT_LIST_HEAD(&discard
);
3560 for (i
= 0; i
< SHRINK_PROMOTE_MAX
; i
++)
3561 INIT_LIST_HEAD(promote
+ i
);
3563 spin_lock_irqsave(&n
->list_lock
, flags
);
3566 * Build lists of slabs to discard or promote.
3568 * Note that concurrent frees may occur while we hold the
3569 * list_lock. page->inuse here is the upper limit.
3571 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
3572 int free
= page
->objects
- page
->inuse
;
3574 /* Do not reread page->inuse */
3577 /* We do not keep full slabs on the list */
3580 if (free
== page
->objects
) {
3581 list_move(&page
->lru
, &discard
);
3583 } else if (free
<= SHRINK_PROMOTE_MAX
)
3584 list_move(&page
->lru
, promote
+ free
- 1);
3588 * Promote the slabs filled up most to the head of the
3591 for (i
= SHRINK_PROMOTE_MAX
- 1; i
>= 0; i
--)
3592 list_splice(promote
+ i
, &n
->partial
);
3594 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3596 /* Release empty slabs */
3597 list_for_each_entry_safe(page
, t
, &discard
, lru
)
3598 discard_slab(s
, page
);
3600 if (slabs_node(s
, node
))
3607 static int slab_mem_going_offline_callback(void *arg
)
3609 struct kmem_cache
*s
;
3611 mutex_lock(&slab_mutex
);
3612 list_for_each_entry(s
, &slab_caches
, list
)
3613 __kmem_cache_shrink(s
, false);
3614 mutex_unlock(&slab_mutex
);
3619 static void slab_mem_offline_callback(void *arg
)
3621 struct kmem_cache_node
*n
;
3622 struct kmem_cache
*s
;
3623 struct memory_notify
*marg
= arg
;
3626 offline_node
= marg
->status_change_nid_normal
;
3629 * If the node still has available memory. we need kmem_cache_node
3632 if (offline_node
< 0)
3635 mutex_lock(&slab_mutex
);
3636 list_for_each_entry(s
, &slab_caches
, list
) {
3637 n
= get_node(s
, offline_node
);
3640 * if n->nr_slabs > 0, slabs still exist on the node
3641 * that is going down. We were unable to free them,
3642 * and offline_pages() function shouldn't call this
3643 * callback. So, we must fail.
3645 BUG_ON(slabs_node(s
, offline_node
));
3647 s
->node
[offline_node
] = NULL
;
3648 kmem_cache_free(kmem_cache_node
, n
);
3651 mutex_unlock(&slab_mutex
);
3654 static int slab_mem_going_online_callback(void *arg
)
3656 struct kmem_cache_node
*n
;
3657 struct kmem_cache
*s
;
3658 struct memory_notify
*marg
= arg
;
3659 int nid
= marg
->status_change_nid_normal
;
3663 * If the node's memory is already available, then kmem_cache_node is
3664 * already created. Nothing to do.
3670 * We are bringing a node online. No memory is available yet. We must
3671 * allocate a kmem_cache_node structure in order to bring the node
3674 mutex_lock(&slab_mutex
);
3675 list_for_each_entry(s
, &slab_caches
, list
) {
3677 * XXX: kmem_cache_alloc_node will fallback to other nodes
3678 * since memory is not yet available from the node that
3681 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
3686 init_kmem_cache_node(n
);
3690 mutex_unlock(&slab_mutex
);
3694 static int slab_memory_callback(struct notifier_block
*self
,
3695 unsigned long action
, void *arg
)
3700 case MEM_GOING_ONLINE
:
3701 ret
= slab_mem_going_online_callback(arg
);
3703 case MEM_GOING_OFFLINE
:
3704 ret
= slab_mem_going_offline_callback(arg
);
3707 case MEM_CANCEL_ONLINE
:
3708 slab_mem_offline_callback(arg
);
3711 case MEM_CANCEL_OFFLINE
:
3715 ret
= notifier_from_errno(ret
);
3721 static struct notifier_block slab_memory_callback_nb
= {
3722 .notifier_call
= slab_memory_callback
,
3723 .priority
= SLAB_CALLBACK_PRI
,
3726 /********************************************************************
3727 * Basic setup of slabs
3728 *******************************************************************/
3731 * Used for early kmem_cache structures that were allocated using
3732 * the page allocator. Allocate them properly then fix up the pointers
3733 * that may be pointing to the wrong kmem_cache structure.
3736 static struct kmem_cache
* __init
bootstrap(struct kmem_cache
*static_cache
)
3739 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
3740 struct kmem_cache_node
*n
;
3742 memcpy(s
, static_cache
, kmem_cache
->object_size
);
3745 * This runs very early, and only the boot processor is supposed to be
3746 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3749 __flush_cpu_slab(s
, smp_processor_id());
3750 for_each_kmem_cache_node(s
, node
, n
) {
3753 list_for_each_entry(p
, &n
->partial
, lru
)
3756 #ifdef CONFIG_SLUB_DEBUG
3757 list_for_each_entry(p
, &n
->full
, lru
)
3761 slab_init_memcg_params(s
);
3762 list_add(&s
->list
, &slab_caches
);
3766 void __init
kmem_cache_init(void)
3768 static __initdata
struct kmem_cache boot_kmem_cache
,
3769 boot_kmem_cache_node
;
3771 if (debug_guardpage_minorder())
3774 kmem_cache_node
= &boot_kmem_cache_node
;
3775 kmem_cache
= &boot_kmem_cache
;
3777 create_boot_cache(kmem_cache_node
, "kmem_cache_node",
3778 sizeof(struct kmem_cache_node
), SLAB_HWCACHE_ALIGN
);
3780 register_hotmemory_notifier(&slab_memory_callback_nb
);
3782 /* Able to allocate the per node structures */
3783 slab_state
= PARTIAL
;
3785 create_boot_cache(kmem_cache
, "kmem_cache",
3786 offsetof(struct kmem_cache
, node
) +
3787 nr_node_ids
* sizeof(struct kmem_cache_node
*),
3788 SLAB_HWCACHE_ALIGN
);
3790 kmem_cache
= bootstrap(&boot_kmem_cache
);
3793 * Allocate kmem_cache_node properly from the kmem_cache slab.
3794 * kmem_cache_node is separately allocated so no need to
3795 * update any list pointers.
3797 kmem_cache_node
= bootstrap(&boot_kmem_cache_node
);
3799 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3800 setup_kmalloc_cache_index_table();
3801 create_kmalloc_caches(0);
3804 register_cpu_notifier(&slab_notifier
);
3807 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
3809 slub_min_order
, slub_max_order
, slub_min_objects
,
3810 nr_cpu_ids
, nr_node_ids
);
3813 void __init
kmem_cache_init_late(void)
3818 __kmem_cache_alias(const char *name
, size_t size
, size_t align
,
3819 unsigned long flags
, void (*ctor
)(void *))
3821 struct kmem_cache
*s
, *c
;
3823 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3828 * Adjust the object sizes so that we clear
3829 * the complete object on kzalloc.
3831 s
->object_size
= max(s
->object_size
, (int)size
);
3832 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3834 for_each_memcg_cache(c
, s
) {
3835 c
->object_size
= s
->object_size
;
3836 c
->inuse
= max_t(int, c
->inuse
,
3837 ALIGN(size
, sizeof(void *)));
3840 if (sysfs_slab_alias(s
, name
)) {
3849 int __kmem_cache_create(struct kmem_cache
*s
, unsigned long flags
)
3853 err
= kmem_cache_open(s
, flags
);
3857 /* Mutex is not taken during early boot */
3858 if (slab_state
<= UP
)
3861 memcg_propagate_slab_attrs(s
);
3862 err
= sysfs_slab_add(s
);
3864 kmem_cache_close(s
);
3871 * Use the cpu notifier to insure that the cpu slabs are flushed when
3874 static int slab_cpuup_callback(struct notifier_block
*nfb
,
3875 unsigned long action
, void *hcpu
)
3877 long cpu
= (long)hcpu
;
3878 struct kmem_cache
*s
;
3879 unsigned long flags
;
3882 case CPU_UP_CANCELED
:
3883 case CPU_UP_CANCELED_FROZEN
:
3885 case CPU_DEAD_FROZEN
:
3886 mutex_lock(&slab_mutex
);
3887 list_for_each_entry(s
, &slab_caches
, list
) {
3888 local_irq_save(flags
);
3889 __flush_cpu_slab(s
, cpu
);
3890 local_irq_restore(flags
);
3892 mutex_unlock(&slab_mutex
);
3900 static struct notifier_block slab_notifier
= {
3901 .notifier_call
= slab_cpuup_callback
3906 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
3908 struct kmem_cache
*s
;
3911 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3912 return kmalloc_large(size
, gfpflags
);
3914 s
= kmalloc_slab(size
, gfpflags
);
3916 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3919 ret
= slab_alloc(s
, gfpflags
, caller
);
3921 /* Honor the call site pointer we received. */
3922 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
3928 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3929 int node
, unsigned long caller
)
3931 struct kmem_cache
*s
;
3934 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3935 ret
= kmalloc_large_node(size
, gfpflags
, node
);
3937 trace_kmalloc_node(caller
, ret
,
3938 size
, PAGE_SIZE
<< get_order(size
),
3944 s
= kmalloc_slab(size
, gfpflags
);
3946 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3949 ret
= slab_alloc_node(s
, gfpflags
, node
, caller
);
3951 /* Honor the call site pointer we received. */
3952 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
3959 static int count_inuse(struct page
*page
)
3964 static int count_total(struct page
*page
)
3966 return page
->objects
;
3970 #ifdef CONFIG_SLUB_DEBUG
3971 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3975 void *addr
= page_address(page
);
3977 if (!check_slab(s
, page
) ||
3978 !on_freelist(s
, page
, NULL
))
3981 /* Now we know that a valid freelist exists */
3982 bitmap_zero(map
, page
->objects
);
3984 get_map(s
, page
, map
);
3985 for_each_object(p
, s
, addr
, page
->objects
) {
3986 if (test_bit(slab_index(p
, s
, addr
), map
))
3987 if (!check_object(s
, page
, p
, SLUB_RED_INACTIVE
))
3991 for_each_object(p
, s
, addr
, page
->objects
)
3992 if (!test_bit(slab_index(p
, s
, addr
), map
))
3993 if (!check_object(s
, page
, p
, SLUB_RED_ACTIVE
))
3998 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
4002 validate_slab(s
, page
, map
);
4006 static int validate_slab_node(struct kmem_cache
*s
,
4007 struct kmem_cache_node
*n
, unsigned long *map
)
4009 unsigned long count
= 0;
4011 unsigned long flags
;
4013 spin_lock_irqsave(&n
->list_lock
, flags
);
4015 list_for_each_entry(page
, &n
->partial
, lru
) {
4016 validate_slab_slab(s
, page
, map
);
4019 if (count
!= n
->nr_partial
)
4020 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4021 s
->name
, count
, n
->nr_partial
);
4023 if (!(s
->flags
& SLAB_STORE_USER
))
4026 list_for_each_entry(page
, &n
->full
, lru
) {
4027 validate_slab_slab(s
, page
, map
);
4030 if (count
!= atomic_long_read(&n
->nr_slabs
))
4031 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4032 s
->name
, count
, atomic_long_read(&n
->nr_slabs
));
4035 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4039 static long validate_slab_cache(struct kmem_cache
*s
)
4042 unsigned long count
= 0;
4043 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4044 sizeof(unsigned long), GFP_KERNEL
);
4045 struct kmem_cache_node
*n
;
4051 for_each_kmem_cache_node(s
, node
, n
)
4052 count
+= validate_slab_node(s
, n
, map
);
4057 * Generate lists of code addresses where slabcache objects are allocated
4062 unsigned long count
;
4069 DECLARE_BITMAP(cpus
, NR_CPUS
);
4075 unsigned long count
;
4076 struct location
*loc
;
4079 static void free_loc_track(struct loc_track
*t
)
4082 free_pages((unsigned long)t
->loc
,
4083 get_order(sizeof(struct location
) * t
->max
));
4086 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
4091 order
= get_order(sizeof(struct location
) * max
);
4093 l
= (void *)__get_free_pages(flags
, order
);
4098 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
4106 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
4107 const struct track
*track
)
4109 long start
, end
, pos
;
4111 unsigned long caddr
;
4112 unsigned long age
= jiffies
- track
->when
;
4118 pos
= start
+ (end
- start
+ 1) / 2;
4121 * There is nothing at "end". If we end up there
4122 * we need to add something to before end.
4127 caddr
= t
->loc
[pos
].addr
;
4128 if (track
->addr
== caddr
) {
4134 if (age
< l
->min_time
)
4136 if (age
> l
->max_time
)
4139 if (track
->pid
< l
->min_pid
)
4140 l
->min_pid
= track
->pid
;
4141 if (track
->pid
> l
->max_pid
)
4142 l
->max_pid
= track
->pid
;
4144 cpumask_set_cpu(track
->cpu
,
4145 to_cpumask(l
->cpus
));
4147 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4151 if (track
->addr
< caddr
)
4158 * Not found. Insert new tracking element.
4160 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
4166 (t
->count
- pos
) * sizeof(struct location
));
4169 l
->addr
= track
->addr
;
4173 l
->min_pid
= track
->pid
;
4174 l
->max_pid
= track
->pid
;
4175 cpumask_clear(to_cpumask(l
->cpus
));
4176 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
4177 nodes_clear(l
->nodes
);
4178 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4182 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
4183 struct page
*page
, enum track_item alloc
,
4186 void *addr
= page_address(page
);
4189 bitmap_zero(map
, page
->objects
);
4190 get_map(s
, page
, map
);
4192 for_each_object(p
, s
, addr
, page
->objects
)
4193 if (!test_bit(slab_index(p
, s
, addr
), map
))
4194 add_location(t
, s
, get_track(s
, p
, alloc
));
4197 static int list_locations(struct kmem_cache
*s
, char *buf
,
4198 enum track_item alloc
)
4202 struct loc_track t
= { 0, 0, NULL
};
4204 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4205 sizeof(unsigned long), GFP_KERNEL
);
4206 struct kmem_cache_node
*n
;
4208 if (!map
|| !alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
4211 return sprintf(buf
, "Out of memory\n");
4213 /* Push back cpu slabs */
4216 for_each_kmem_cache_node(s
, node
, n
) {
4217 unsigned long flags
;
4220 if (!atomic_long_read(&n
->nr_slabs
))
4223 spin_lock_irqsave(&n
->list_lock
, flags
);
4224 list_for_each_entry(page
, &n
->partial
, lru
)
4225 process_slab(&t
, s
, page
, alloc
, map
);
4226 list_for_each_entry(page
, &n
->full
, lru
)
4227 process_slab(&t
, s
, page
, alloc
, map
);
4228 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4231 for (i
= 0; i
< t
.count
; i
++) {
4232 struct location
*l
= &t
.loc
[i
];
4234 if (len
> PAGE_SIZE
- KSYM_SYMBOL_LEN
- 100)
4236 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
4239 len
+= sprintf(buf
+ len
, "%pS", (void *)l
->addr
);
4241 len
+= sprintf(buf
+ len
, "<not-available>");
4243 if (l
->sum_time
!= l
->min_time
) {
4244 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
4246 (long)div_u64(l
->sum_time
, l
->count
),
4249 len
+= sprintf(buf
+ len
, " age=%ld",
4252 if (l
->min_pid
!= l
->max_pid
)
4253 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
4254 l
->min_pid
, l
->max_pid
);
4256 len
+= sprintf(buf
+ len
, " pid=%ld",
4259 if (num_online_cpus() > 1 &&
4260 !cpumask_empty(to_cpumask(l
->cpus
)) &&
4261 len
< PAGE_SIZE
- 60)
4262 len
+= scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4264 cpumask_pr_args(to_cpumask(l
->cpus
)));
4266 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
) &&
4267 len
< PAGE_SIZE
- 60)
4268 len
+= scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4270 nodemask_pr_args(&l
->nodes
));
4272 len
+= sprintf(buf
+ len
, "\n");
4278 len
+= sprintf(buf
, "No data\n");
4283 #ifdef SLUB_RESILIENCY_TEST
4284 static void __init
resiliency_test(void)
4288 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 16 || KMALLOC_SHIFT_HIGH
< 10);
4290 pr_err("SLUB resiliency testing\n");
4291 pr_err("-----------------------\n");
4292 pr_err("A. Corruption after allocation\n");
4294 p
= kzalloc(16, GFP_KERNEL
);
4296 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4299 validate_slab_cache(kmalloc_caches
[4]);
4301 /* Hmmm... The next two are dangerous */
4302 p
= kzalloc(32, GFP_KERNEL
);
4303 p
[32 + sizeof(void *)] = 0x34;
4304 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4306 pr_err("If allocated object is overwritten then not detectable\n\n");
4308 validate_slab_cache(kmalloc_caches
[5]);
4309 p
= kzalloc(64, GFP_KERNEL
);
4310 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
4312 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4314 pr_err("If allocated object is overwritten then not detectable\n\n");
4315 validate_slab_cache(kmalloc_caches
[6]);
4317 pr_err("\nB. Corruption after free\n");
4318 p
= kzalloc(128, GFP_KERNEL
);
4321 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
4322 validate_slab_cache(kmalloc_caches
[7]);
4324 p
= kzalloc(256, GFP_KERNEL
);
4327 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
4328 validate_slab_cache(kmalloc_caches
[8]);
4330 p
= kzalloc(512, GFP_KERNEL
);
4333 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
4334 validate_slab_cache(kmalloc_caches
[9]);
4338 static void resiliency_test(void) {};
4343 enum slab_stat_type
{
4344 SL_ALL
, /* All slabs */
4345 SL_PARTIAL
, /* Only partially allocated slabs */
4346 SL_CPU
, /* Only slabs used for cpu caches */
4347 SL_OBJECTS
, /* Determine allocated objects not slabs */
4348 SL_TOTAL
/* Determine object capacity not slabs */
4351 #define SO_ALL (1 << SL_ALL)
4352 #define SO_PARTIAL (1 << SL_PARTIAL)
4353 #define SO_CPU (1 << SL_CPU)
4354 #define SO_OBJECTS (1 << SL_OBJECTS)
4355 #define SO_TOTAL (1 << SL_TOTAL)
4357 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
4358 char *buf
, unsigned long flags
)
4360 unsigned long total
= 0;
4363 unsigned long *nodes
;
4365 nodes
= kzalloc(sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
4369 if (flags
& SO_CPU
) {
4372 for_each_possible_cpu(cpu
) {
4373 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
,
4378 page
= READ_ONCE(c
->page
);
4382 node
= page_to_nid(page
);
4383 if (flags
& SO_TOTAL
)
4385 else if (flags
& SO_OBJECTS
)
4393 page
= READ_ONCE(c
->partial
);
4395 node
= page_to_nid(page
);
4396 if (flags
& SO_TOTAL
)
4398 else if (flags
& SO_OBJECTS
)
4409 #ifdef CONFIG_SLUB_DEBUG
4410 if (flags
& SO_ALL
) {
4411 struct kmem_cache_node
*n
;
4413 for_each_kmem_cache_node(s
, node
, n
) {
4415 if (flags
& SO_TOTAL
)
4416 x
= atomic_long_read(&n
->total_objects
);
4417 else if (flags
& SO_OBJECTS
)
4418 x
= atomic_long_read(&n
->total_objects
) -
4419 count_partial(n
, count_free
);
4421 x
= atomic_long_read(&n
->nr_slabs
);
4428 if (flags
& SO_PARTIAL
) {
4429 struct kmem_cache_node
*n
;
4431 for_each_kmem_cache_node(s
, node
, n
) {
4432 if (flags
& SO_TOTAL
)
4433 x
= count_partial(n
, count_total
);
4434 else if (flags
& SO_OBJECTS
)
4435 x
= count_partial(n
, count_inuse
);
4442 x
= sprintf(buf
, "%lu", total
);
4444 for (node
= 0; node
< nr_node_ids
; node
++)
4446 x
+= sprintf(buf
+ x
, " N%d=%lu",
4451 return x
+ sprintf(buf
+ x
, "\n");
4454 #ifdef CONFIG_SLUB_DEBUG
4455 static int any_slab_objects(struct kmem_cache
*s
)
4458 struct kmem_cache_node
*n
;
4460 for_each_kmem_cache_node(s
, node
, n
)
4461 if (atomic_long_read(&n
->total_objects
))
4468 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4469 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4471 struct slab_attribute
{
4472 struct attribute attr
;
4473 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
4474 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
4477 #define SLAB_ATTR_RO(_name) \
4478 static struct slab_attribute _name##_attr = \
4479 __ATTR(_name, 0400, _name##_show, NULL)
4481 #define SLAB_ATTR(_name) \
4482 static struct slab_attribute _name##_attr = \
4483 __ATTR(_name, 0600, _name##_show, _name##_store)
4485 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
4487 return sprintf(buf
, "%d\n", s
->size
);
4489 SLAB_ATTR_RO(slab_size
);
4491 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
4493 return sprintf(buf
, "%d\n", s
->align
);
4495 SLAB_ATTR_RO(align
);
4497 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
4499 return sprintf(buf
, "%d\n", s
->object_size
);
4501 SLAB_ATTR_RO(object_size
);
4503 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
4505 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
4507 SLAB_ATTR_RO(objs_per_slab
);
4509 static ssize_t
order_store(struct kmem_cache
*s
,
4510 const char *buf
, size_t length
)
4512 unsigned long order
;
4515 err
= kstrtoul(buf
, 10, &order
);
4519 if (order
> slub_max_order
|| order
< slub_min_order
)
4522 calculate_sizes(s
, order
);
4526 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
4528 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
4532 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
4534 return sprintf(buf
, "%lu\n", s
->min_partial
);
4537 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
4543 err
= kstrtoul(buf
, 10, &min
);
4547 set_min_partial(s
, min
);
4550 SLAB_ATTR(min_partial
);
4552 static ssize_t
cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4554 return sprintf(buf
, "%u\n", s
->cpu_partial
);
4557 static ssize_t
cpu_partial_store(struct kmem_cache
*s
, const char *buf
,
4560 unsigned long objects
;
4563 err
= kstrtoul(buf
, 10, &objects
);
4566 if (objects
&& !kmem_cache_has_cpu_partial(s
))
4569 s
->cpu_partial
= objects
;
4573 SLAB_ATTR(cpu_partial
);
4575 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
4579 return sprintf(buf
, "%pS\n", s
->ctor
);
4583 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
4585 return sprintf(buf
, "%d\n", s
->refcount
< 0 ? 0 : s
->refcount
- 1);
4587 SLAB_ATTR_RO(aliases
);
4589 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
4591 return show_slab_objects(s
, buf
, SO_PARTIAL
);
4593 SLAB_ATTR_RO(partial
);
4595 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
4597 return show_slab_objects(s
, buf
, SO_CPU
);
4599 SLAB_ATTR_RO(cpu_slabs
);
4601 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
4603 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
4605 SLAB_ATTR_RO(objects
);
4607 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
4609 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
4611 SLAB_ATTR_RO(objects_partial
);
4613 static ssize_t
slabs_cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4620 for_each_online_cpu(cpu
) {
4621 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
)->partial
;
4624 pages
+= page
->pages
;
4625 objects
+= page
->pobjects
;
4629 len
= sprintf(buf
, "%d(%d)", objects
, pages
);
4632 for_each_online_cpu(cpu
) {
4633 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
) ->partial
;
4635 if (page
&& len
< PAGE_SIZE
- 20)
4636 len
+= sprintf(buf
+ len
, " C%d=%d(%d)", cpu
,
4637 page
->pobjects
, page
->pages
);
4640 return len
+ sprintf(buf
+ len
, "\n");
4642 SLAB_ATTR_RO(slabs_cpu_partial
);
4644 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
4646 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
4649 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
4650 const char *buf
, size_t length
)
4652 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
4654 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
4657 SLAB_ATTR(reclaim_account
);
4659 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
4661 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
4663 SLAB_ATTR_RO(hwcache_align
);
4665 #ifdef CONFIG_ZONE_DMA
4666 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
4668 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
4670 SLAB_ATTR_RO(cache_dma
);
4673 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
4675 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
4677 SLAB_ATTR_RO(destroy_by_rcu
);
4679 static ssize_t
reserved_show(struct kmem_cache
*s
, char *buf
)
4681 return sprintf(buf
, "%d\n", s
->reserved
);
4683 SLAB_ATTR_RO(reserved
);
4685 #ifdef CONFIG_SLUB_DEBUG
4686 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
4688 return show_slab_objects(s
, buf
, SO_ALL
);
4690 SLAB_ATTR_RO(slabs
);
4692 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
4694 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
4696 SLAB_ATTR_RO(total_objects
);
4698 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
4700 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
4703 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
4704 const char *buf
, size_t length
)
4706 s
->flags
&= ~SLAB_DEBUG_FREE
;
4707 if (buf
[0] == '1') {
4708 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4709 s
->flags
|= SLAB_DEBUG_FREE
;
4713 SLAB_ATTR(sanity_checks
);
4715 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
4717 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
4720 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
4724 * Tracing a merged cache is going to give confusing results
4725 * as well as cause other issues like converting a mergeable
4726 * cache into an umergeable one.
4728 if (s
->refcount
> 1)
4731 s
->flags
&= ~SLAB_TRACE
;
4732 if (buf
[0] == '1') {
4733 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4734 s
->flags
|= SLAB_TRACE
;
4740 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
4742 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
4745 static ssize_t
red_zone_store(struct kmem_cache
*s
,
4746 const char *buf
, size_t length
)
4748 if (any_slab_objects(s
))
4751 s
->flags
&= ~SLAB_RED_ZONE
;
4752 if (buf
[0] == '1') {
4753 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4754 s
->flags
|= SLAB_RED_ZONE
;
4756 calculate_sizes(s
, -1);
4759 SLAB_ATTR(red_zone
);
4761 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
4763 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
4766 static ssize_t
poison_store(struct kmem_cache
*s
,
4767 const char *buf
, size_t length
)
4769 if (any_slab_objects(s
))
4772 s
->flags
&= ~SLAB_POISON
;
4773 if (buf
[0] == '1') {
4774 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4775 s
->flags
|= SLAB_POISON
;
4777 calculate_sizes(s
, -1);
4782 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
4784 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
4787 static ssize_t
store_user_store(struct kmem_cache
*s
,
4788 const char *buf
, size_t length
)
4790 if (any_slab_objects(s
))
4793 s
->flags
&= ~SLAB_STORE_USER
;
4794 if (buf
[0] == '1') {
4795 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4796 s
->flags
|= SLAB_STORE_USER
;
4798 calculate_sizes(s
, -1);
4801 SLAB_ATTR(store_user
);
4803 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4808 static ssize_t
validate_store(struct kmem_cache
*s
,
4809 const char *buf
, size_t length
)
4813 if (buf
[0] == '1') {
4814 ret
= validate_slab_cache(s
);
4820 SLAB_ATTR(validate
);
4822 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4824 if (!(s
->flags
& SLAB_STORE_USER
))
4826 return list_locations(s
, buf
, TRACK_ALLOC
);
4828 SLAB_ATTR_RO(alloc_calls
);
4830 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4832 if (!(s
->flags
& SLAB_STORE_USER
))
4834 return list_locations(s
, buf
, TRACK_FREE
);
4836 SLAB_ATTR_RO(free_calls
);
4837 #endif /* CONFIG_SLUB_DEBUG */
4839 #ifdef CONFIG_FAILSLAB
4840 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
4842 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
4845 static ssize_t
failslab_store(struct kmem_cache
*s
, const char *buf
,
4848 if (s
->refcount
> 1)
4851 s
->flags
&= ~SLAB_FAILSLAB
;
4853 s
->flags
|= SLAB_FAILSLAB
;
4856 SLAB_ATTR(failslab
);
4859 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4864 static ssize_t
shrink_store(struct kmem_cache
*s
,
4865 const char *buf
, size_t length
)
4868 kmem_cache_shrink(s
);
4876 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4878 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4881 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4882 const char *buf
, size_t length
)
4884 unsigned long ratio
;
4887 err
= kstrtoul(buf
, 10, &ratio
);
4892 s
->remote_node_defrag_ratio
= ratio
* 10;
4896 SLAB_ATTR(remote_node_defrag_ratio
);
4899 #ifdef CONFIG_SLUB_STATS
4900 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
4902 unsigned long sum
= 0;
4905 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
4910 for_each_online_cpu(cpu
) {
4911 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
4917 len
= sprintf(buf
, "%lu", sum
);
4920 for_each_online_cpu(cpu
) {
4921 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
4922 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
4926 return len
+ sprintf(buf
+ len
, "\n");
4929 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
4933 for_each_online_cpu(cpu
)
4934 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
4937 #define STAT_ATTR(si, text) \
4938 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4940 return show_stat(s, buf, si); \
4942 static ssize_t text##_store(struct kmem_cache *s, \
4943 const char *buf, size_t length) \
4945 if (buf[0] != '0') \
4947 clear_stat(s, si); \
4952 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4953 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
4954 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
4955 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
4956 STAT_ATTR(FREE_FROZEN
, free_frozen
);
4957 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
4958 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
4959 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
4960 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
4961 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
4962 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
4963 STAT_ATTR(FREE_SLAB
, free_slab
);
4964 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
4965 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
4966 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
4967 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4968 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4969 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4970 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
4971 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
4972 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
4973 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
4974 STAT_ATTR(CPU_PARTIAL_ALLOC
, cpu_partial_alloc
);
4975 STAT_ATTR(CPU_PARTIAL_FREE
, cpu_partial_free
);
4976 STAT_ATTR(CPU_PARTIAL_NODE
, cpu_partial_node
);
4977 STAT_ATTR(CPU_PARTIAL_DRAIN
, cpu_partial_drain
);
4980 static struct attribute
*slab_attrs
[] = {
4981 &slab_size_attr
.attr
,
4982 &object_size_attr
.attr
,
4983 &objs_per_slab_attr
.attr
,
4985 &min_partial_attr
.attr
,
4986 &cpu_partial_attr
.attr
,
4988 &objects_partial_attr
.attr
,
4990 &cpu_slabs_attr
.attr
,
4994 &hwcache_align_attr
.attr
,
4995 &reclaim_account_attr
.attr
,
4996 &destroy_by_rcu_attr
.attr
,
4998 &reserved_attr
.attr
,
4999 &slabs_cpu_partial_attr
.attr
,
5000 #ifdef CONFIG_SLUB_DEBUG
5001 &total_objects_attr
.attr
,
5003 &sanity_checks_attr
.attr
,
5005 &red_zone_attr
.attr
,
5007 &store_user_attr
.attr
,
5008 &validate_attr
.attr
,
5009 &alloc_calls_attr
.attr
,
5010 &free_calls_attr
.attr
,
5012 #ifdef CONFIG_ZONE_DMA
5013 &cache_dma_attr
.attr
,
5016 &remote_node_defrag_ratio_attr
.attr
,
5018 #ifdef CONFIG_SLUB_STATS
5019 &alloc_fastpath_attr
.attr
,
5020 &alloc_slowpath_attr
.attr
,
5021 &free_fastpath_attr
.attr
,
5022 &free_slowpath_attr
.attr
,
5023 &free_frozen_attr
.attr
,
5024 &free_add_partial_attr
.attr
,
5025 &free_remove_partial_attr
.attr
,
5026 &alloc_from_partial_attr
.attr
,
5027 &alloc_slab_attr
.attr
,
5028 &alloc_refill_attr
.attr
,
5029 &alloc_node_mismatch_attr
.attr
,
5030 &free_slab_attr
.attr
,
5031 &cpuslab_flush_attr
.attr
,
5032 &deactivate_full_attr
.attr
,
5033 &deactivate_empty_attr
.attr
,
5034 &deactivate_to_head_attr
.attr
,
5035 &deactivate_to_tail_attr
.attr
,
5036 &deactivate_remote_frees_attr
.attr
,
5037 &deactivate_bypass_attr
.attr
,
5038 &order_fallback_attr
.attr
,
5039 &cmpxchg_double_fail_attr
.attr
,
5040 &cmpxchg_double_cpu_fail_attr
.attr
,
5041 &cpu_partial_alloc_attr
.attr
,
5042 &cpu_partial_free_attr
.attr
,
5043 &cpu_partial_node_attr
.attr
,
5044 &cpu_partial_drain_attr
.attr
,
5046 #ifdef CONFIG_FAILSLAB
5047 &failslab_attr
.attr
,
5053 static struct attribute_group slab_attr_group
= {
5054 .attrs
= slab_attrs
,
5057 static ssize_t
slab_attr_show(struct kobject
*kobj
,
5058 struct attribute
*attr
,
5061 struct slab_attribute
*attribute
;
5062 struct kmem_cache
*s
;
5065 attribute
= to_slab_attr(attr
);
5068 if (!attribute
->show
)
5071 err
= attribute
->show(s
, buf
);
5076 static ssize_t
slab_attr_store(struct kobject
*kobj
,
5077 struct attribute
*attr
,
5078 const char *buf
, size_t len
)
5080 struct slab_attribute
*attribute
;
5081 struct kmem_cache
*s
;
5084 attribute
= to_slab_attr(attr
);
5087 if (!attribute
->store
)
5090 err
= attribute
->store(s
, buf
, len
);
5091 #ifdef CONFIG_MEMCG_KMEM
5092 if (slab_state
>= FULL
&& err
>= 0 && is_root_cache(s
)) {
5093 struct kmem_cache
*c
;
5095 mutex_lock(&slab_mutex
);
5096 if (s
->max_attr_size
< len
)
5097 s
->max_attr_size
= len
;
5100 * This is a best effort propagation, so this function's return
5101 * value will be determined by the parent cache only. This is
5102 * basically because not all attributes will have a well
5103 * defined semantics for rollbacks - most of the actions will
5104 * have permanent effects.
5106 * Returning the error value of any of the children that fail
5107 * is not 100 % defined, in the sense that users seeing the
5108 * error code won't be able to know anything about the state of
5111 * Only returning the error code for the parent cache at least
5112 * has well defined semantics. The cache being written to
5113 * directly either failed or succeeded, in which case we loop
5114 * through the descendants with best-effort propagation.
5116 for_each_memcg_cache(c
, s
)
5117 attribute
->store(c
, buf
, len
);
5118 mutex_unlock(&slab_mutex
);
5124 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
)
5126 #ifdef CONFIG_MEMCG_KMEM
5128 char *buffer
= NULL
;
5129 struct kmem_cache
*root_cache
;
5131 if (is_root_cache(s
))
5134 root_cache
= s
->memcg_params
.root_cache
;
5137 * This mean this cache had no attribute written. Therefore, no point
5138 * in copying default values around
5140 if (!root_cache
->max_attr_size
)
5143 for (i
= 0; i
< ARRAY_SIZE(slab_attrs
); i
++) {
5146 struct slab_attribute
*attr
= to_slab_attr(slab_attrs
[i
]);
5148 if (!attr
|| !attr
->store
|| !attr
->show
)
5152 * It is really bad that we have to allocate here, so we will
5153 * do it only as a fallback. If we actually allocate, though,
5154 * we can just use the allocated buffer until the end.
5156 * Most of the slub attributes will tend to be very small in
5157 * size, but sysfs allows buffers up to a page, so they can
5158 * theoretically happen.
5162 else if (root_cache
->max_attr_size
< ARRAY_SIZE(mbuf
))
5165 buffer
= (char *) get_zeroed_page(GFP_KERNEL
);
5166 if (WARN_ON(!buffer
))
5171 attr
->show(root_cache
, buf
);
5172 attr
->store(s
, buf
, strlen(buf
));
5176 free_page((unsigned long)buffer
);
5180 static void kmem_cache_release(struct kobject
*k
)
5182 slab_kmem_cache_release(to_slab(k
));
5185 static const struct sysfs_ops slab_sysfs_ops
= {
5186 .show
= slab_attr_show
,
5187 .store
= slab_attr_store
,
5190 static struct kobj_type slab_ktype
= {
5191 .sysfs_ops
= &slab_sysfs_ops
,
5192 .release
= kmem_cache_release
,
5195 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
5197 struct kobj_type
*ktype
= get_ktype(kobj
);
5199 if (ktype
== &slab_ktype
)
5204 static const struct kset_uevent_ops slab_uevent_ops
= {
5205 .filter
= uevent_filter
,
5208 static struct kset
*slab_kset
;
5210 static inline struct kset
*cache_kset(struct kmem_cache
*s
)
5212 #ifdef CONFIG_MEMCG_KMEM
5213 if (!is_root_cache(s
))
5214 return s
->memcg_params
.root_cache
->memcg_kset
;
5219 #define ID_STR_LENGTH 64
5221 /* Create a unique string id for a slab cache:
5223 * Format :[flags-]size
5225 static char *create_unique_id(struct kmem_cache
*s
)
5227 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
5234 * First flags affecting slabcache operations. We will only
5235 * get here for aliasable slabs so we do not need to support
5236 * too many flags. The flags here must cover all flags that
5237 * are matched during merging to guarantee that the id is
5240 if (s
->flags
& SLAB_CACHE_DMA
)
5242 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
5244 if (s
->flags
& SLAB_DEBUG_FREE
)
5246 if (!(s
->flags
& SLAB_NOTRACK
))
5250 p
+= sprintf(p
, "%07d", s
->size
);
5252 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
5256 static int sysfs_slab_add(struct kmem_cache
*s
)
5260 int unmergeable
= slab_unmergeable(s
);
5264 * Slabcache can never be merged so we can use the name proper.
5265 * This is typically the case for debug situations. In that
5266 * case we can catch duplicate names easily.
5268 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
5272 * Create a unique name for the slab as a target
5275 name
= create_unique_id(s
);
5278 s
->kobj
.kset
= cache_kset(s
);
5279 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, "%s", name
);
5283 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
5287 #ifdef CONFIG_MEMCG_KMEM
5288 if (is_root_cache(s
)) {
5289 s
->memcg_kset
= kset_create_and_add("cgroup", NULL
, &s
->kobj
);
5290 if (!s
->memcg_kset
) {
5297 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
5299 /* Setup first alias */
5300 sysfs_slab_alias(s
, s
->name
);
5307 kobject_del(&s
->kobj
);
5311 void sysfs_slab_remove(struct kmem_cache
*s
)
5313 if (slab_state
< FULL
)
5315 * Sysfs has not been setup yet so no need to remove the
5320 #ifdef CONFIG_MEMCG_KMEM
5321 kset_unregister(s
->memcg_kset
);
5323 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
5324 kobject_del(&s
->kobj
);
5325 kobject_put(&s
->kobj
);
5329 * Need to buffer aliases during bootup until sysfs becomes
5330 * available lest we lose that information.
5332 struct saved_alias
{
5333 struct kmem_cache
*s
;
5335 struct saved_alias
*next
;
5338 static struct saved_alias
*alias_list
;
5340 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5342 struct saved_alias
*al
;
5344 if (slab_state
== FULL
) {
5346 * If we have a leftover link then remove it.
5348 sysfs_remove_link(&slab_kset
->kobj
, name
);
5349 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5352 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5358 al
->next
= alias_list
;
5363 static int __init
slab_sysfs_init(void)
5365 struct kmem_cache
*s
;
5368 mutex_lock(&slab_mutex
);
5370 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
5372 mutex_unlock(&slab_mutex
);
5373 pr_err("Cannot register slab subsystem.\n");
5379 list_for_each_entry(s
, &slab_caches
, list
) {
5380 err
= sysfs_slab_add(s
);
5382 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5386 while (alias_list
) {
5387 struct saved_alias
*al
= alias_list
;
5389 alias_list
= alias_list
->next
;
5390 err
= sysfs_slab_alias(al
->s
, al
->name
);
5392 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5397 mutex_unlock(&slab_mutex
);
5402 __initcall(slab_sysfs_init
);
5403 #endif /* CONFIG_SYSFS */
5406 * The /proc/slabinfo ABI
5408 #ifdef CONFIG_SLABINFO
5409 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
)
5411 unsigned long nr_slabs
= 0;
5412 unsigned long nr_objs
= 0;
5413 unsigned long nr_free
= 0;
5415 struct kmem_cache_node
*n
;
5417 for_each_kmem_cache_node(s
, node
, n
) {
5418 nr_slabs
+= node_nr_slabs(n
);
5419 nr_objs
+= node_nr_objs(n
);
5420 nr_free
+= count_partial(n
, count_free
);
5423 sinfo
->active_objs
= nr_objs
- nr_free
;
5424 sinfo
->num_objs
= nr_objs
;
5425 sinfo
->active_slabs
= nr_slabs
;
5426 sinfo
->num_slabs
= nr_slabs
;
5427 sinfo
->objects_per_slab
= oo_objects(s
->oo
);
5428 sinfo
->cache_order
= oo_order(s
->oo
);
5431 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
)
5435 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
5436 size_t count
, loff_t
*ppos
)
5440 #endif /* CONFIG_SLABINFO */