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 VM_BUG_ON_PAGE(PageTail(page
), page
);
342 bit_spin_lock(PG_locked
, &page
->flags
);
345 static __always_inline
void slab_unlock(struct page
*page
)
347 VM_BUG_ON_PAGE(PageTail(page
), page
);
348 __bit_spin_unlock(PG_locked
, &page
->flags
);
351 static inline void set_page_slub_counters(struct page
*page
, unsigned long counters_new
)
354 tmp
.counters
= counters_new
;
356 * page->counters can cover frozen/inuse/objects as well
357 * as page->_count. If we assign to ->counters directly
358 * we run the risk of losing updates to page->_count, so
359 * be careful and only assign to the fields we need.
361 page
->frozen
= tmp
.frozen
;
362 page
->inuse
= tmp
.inuse
;
363 page
->objects
= tmp
.objects
;
366 /* Interrupts must be disabled (for the fallback code to work right) */
367 static inline bool __cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
368 void *freelist_old
, unsigned long counters_old
,
369 void *freelist_new
, unsigned long counters_new
,
372 VM_BUG_ON(!irqs_disabled());
373 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
374 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
375 if (s
->flags
& __CMPXCHG_DOUBLE
) {
376 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
377 freelist_old
, counters_old
,
378 freelist_new
, counters_new
))
384 if (page
->freelist
== freelist_old
&&
385 page
->counters
== counters_old
) {
386 page
->freelist
= freelist_new
;
387 set_page_slub_counters(page
, counters_new
);
395 stat(s
, CMPXCHG_DOUBLE_FAIL
);
397 #ifdef SLUB_DEBUG_CMPXCHG
398 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
404 static inline bool cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
405 void *freelist_old
, unsigned long counters_old
,
406 void *freelist_new
, unsigned long counters_new
,
409 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
410 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
411 if (s
->flags
& __CMPXCHG_DOUBLE
) {
412 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
413 freelist_old
, counters_old
,
414 freelist_new
, counters_new
))
421 local_irq_save(flags
);
423 if (page
->freelist
== freelist_old
&&
424 page
->counters
== counters_old
) {
425 page
->freelist
= freelist_new
;
426 set_page_slub_counters(page
, counters_new
);
428 local_irq_restore(flags
);
432 local_irq_restore(flags
);
436 stat(s
, CMPXCHG_DOUBLE_FAIL
);
438 #ifdef SLUB_DEBUG_CMPXCHG
439 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
445 #ifdef CONFIG_SLUB_DEBUG
447 * Determine a map of object in use on a page.
449 * Node listlock must be held to guarantee that the page does
450 * not vanish from under us.
452 static void get_map(struct kmem_cache
*s
, struct page
*page
, unsigned long *map
)
455 void *addr
= page_address(page
);
457 for (p
= page
->freelist
; p
; p
= get_freepointer(s
, p
))
458 set_bit(slab_index(p
, s
, addr
), map
);
464 #if defined(CONFIG_SLUB_DEBUG_ON)
465 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
466 #elif defined(CONFIG_KASAN)
467 static int slub_debug
= SLAB_STORE_USER
;
469 static int slub_debug
;
472 static char *slub_debug_slabs
;
473 static int disable_higher_order_debug
;
476 * slub is about to manipulate internal object metadata. This memory lies
477 * outside the range of the allocated object, so accessing it would normally
478 * be reported by kasan as a bounds error. metadata_access_enable() is used
479 * to tell kasan that these accesses are OK.
481 static inline void metadata_access_enable(void)
483 kasan_disable_current();
486 static inline void metadata_access_disable(void)
488 kasan_enable_current();
494 static void print_section(char *text
, u8
*addr
, unsigned int length
)
496 metadata_access_enable();
497 print_hex_dump(KERN_ERR
, text
, DUMP_PREFIX_ADDRESS
, 16, 1, addr
,
499 metadata_access_disable();
502 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
503 enum track_item alloc
)
508 p
= object
+ s
->offset
+ sizeof(void *);
510 p
= object
+ s
->inuse
;
515 static void set_track(struct kmem_cache
*s
, void *object
,
516 enum track_item alloc
, unsigned long addr
)
518 struct track
*p
= get_track(s
, object
, alloc
);
521 #ifdef CONFIG_STACKTRACE
522 struct stack_trace trace
;
525 trace
.nr_entries
= 0;
526 trace
.max_entries
= TRACK_ADDRS_COUNT
;
527 trace
.entries
= p
->addrs
;
529 metadata_access_enable();
530 save_stack_trace(&trace
);
531 metadata_access_disable();
533 /* See rant in lockdep.c */
534 if (trace
.nr_entries
!= 0 &&
535 trace
.entries
[trace
.nr_entries
- 1] == ULONG_MAX
)
538 for (i
= trace
.nr_entries
; i
< TRACK_ADDRS_COUNT
; i
++)
542 p
->cpu
= smp_processor_id();
543 p
->pid
= current
->pid
;
546 memset(p
, 0, sizeof(struct track
));
549 static void init_tracking(struct kmem_cache
*s
, void *object
)
551 if (!(s
->flags
& SLAB_STORE_USER
))
554 set_track(s
, object
, TRACK_FREE
, 0UL);
555 set_track(s
, object
, TRACK_ALLOC
, 0UL);
558 static void print_track(const char *s
, struct track
*t
)
563 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
564 s
, (void *)t
->addr
, jiffies
- t
->when
, t
->cpu
, t
->pid
);
565 #ifdef CONFIG_STACKTRACE
568 for (i
= 0; i
< TRACK_ADDRS_COUNT
; i
++)
570 pr_err("\t%pS\n", (void *)t
->addrs
[i
]);
577 static void print_tracking(struct kmem_cache
*s
, void *object
)
579 if (!(s
->flags
& SLAB_STORE_USER
))
582 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
583 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
586 static void print_page_info(struct page
*page
)
588 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
589 page
, page
->objects
, page
->inuse
, page
->freelist
, page
->flags
);
593 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
595 struct va_format vaf
;
601 pr_err("=============================================================================\n");
602 pr_err("BUG %s (%s): %pV\n", s
->name
, print_tainted(), &vaf
);
603 pr_err("-----------------------------------------------------------------------------\n\n");
605 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
609 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
611 struct va_format vaf
;
617 pr_err("FIX %s: %pV\n", s
->name
, &vaf
);
621 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
623 unsigned int off
; /* Offset of last byte */
624 u8
*addr
= page_address(page
);
626 print_tracking(s
, p
);
628 print_page_info(page
);
630 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
631 p
, p
- addr
, get_freepointer(s
, p
));
634 print_section("Bytes b4 ", p
- 16, 16);
636 print_section("Object ", p
, min_t(unsigned long, s
->object_size
,
638 if (s
->flags
& SLAB_RED_ZONE
)
639 print_section("Redzone ", p
+ s
->object_size
,
640 s
->inuse
- s
->object_size
);
643 off
= s
->offset
+ sizeof(void *);
647 if (s
->flags
& SLAB_STORE_USER
)
648 off
+= 2 * sizeof(struct track
);
651 /* Beginning of the filler is the free pointer */
652 print_section("Padding ", p
+ off
, s
->size
- off
);
657 void object_err(struct kmem_cache
*s
, struct page
*page
,
658 u8
*object
, char *reason
)
660 slab_bug(s
, "%s", reason
);
661 print_trailer(s
, page
, object
);
664 static void slab_err(struct kmem_cache
*s
, struct page
*page
,
665 const char *fmt
, ...)
671 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
673 slab_bug(s
, "%s", buf
);
674 print_page_info(page
);
678 static void init_object(struct kmem_cache
*s
, void *object
, u8 val
)
682 if (s
->flags
& __OBJECT_POISON
) {
683 memset(p
, POISON_FREE
, s
->object_size
- 1);
684 p
[s
->object_size
- 1] = POISON_END
;
687 if (s
->flags
& SLAB_RED_ZONE
)
688 memset(p
+ s
->object_size
, val
, s
->inuse
- s
->object_size
);
691 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
692 void *from
, void *to
)
694 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
695 memset(from
, data
, to
- from
);
698 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
699 u8
*object
, char *what
,
700 u8
*start
, unsigned int value
, unsigned int bytes
)
705 metadata_access_enable();
706 fault
= memchr_inv(start
, value
, bytes
);
707 metadata_access_disable();
712 while (end
> fault
&& end
[-1] == value
)
715 slab_bug(s
, "%s overwritten", what
);
716 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
717 fault
, end
- 1, fault
[0], value
);
718 print_trailer(s
, page
, object
);
720 restore_bytes(s
, what
, value
, fault
, end
);
728 * Bytes of the object to be managed.
729 * If the freepointer may overlay the object then the free
730 * pointer is the first word of the object.
732 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
735 * object + s->object_size
736 * Padding to reach word boundary. This is also used for Redzoning.
737 * Padding is extended by another word if Redzoning is enabled and
738 * object_size == inuse.
740 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
741 * 0xcc (RED_ACTIVE) for objects in use.
744 * Meta data starts here.
746 * A. Free pointer (if we cannot overwrite object on free)
747 * B. Tracking data for SLAB_STORE_USER
748 * C. Padding to reach required alignment boundary or at mininum
749 * one word if debugging is on to be able to detect writes
750 * before the word boundary.
752 * Padding is done using 0x5a (POISON_INUSE)
755 * Nothing is used beyond s->size.
757 * If slabcaches are merged then the object_size and inuse boundaries are mostly
758 * ignored. And therefore no slab options that rely on these boundaries
759 * may be used with merged slabcaches.
762 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
764 unsigned long off
= s
->inuse
; /* The end of info */
767 /* Freepointer is placed after the object. */
768 off
+= sizeof(void *);
770 if (s
->flags
& SLAB_STORE_USER
)
771 /* We also have user information there */
772 off
+= 2 * sizeof(struct track
);
777 return check_bytes_and_report(s
, page
, p
, "Object padding",
778 p
+ off
, POISON_INUSE
, s
->size
- off
);
781 /* Check the pad bytes at the end of a slab page */
782 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
790 if (!(s
->flags
& SLAB_POISON
))
793 start
= page_address(page
);
794 length
= (PAGE_SIZE
<< compound_order(page
)) - s
->reserved
;
795 end
= start
+ length
;
796 remainder
= length
% s
->size
;
800 metadata_access_enable();
801 fault
= memchr_inv(end
- remainder
, POISON_INUSE
, remainder
);
802 metadata_access_disable();
805 while (end
> fault
&& end
[-1] == POISON_INUSE
)
808 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
809 print_section("Padding ", end
- remainder
, remainder
);
811 restore_bytes(s
, "slab padding", POISON_INUSE
, end
- remainder
, end
);
815 static int check_object(struct kmem_cache
*s
, struct page
*page
,
816 void *object
, u8 val
)
819 u8
*endobject
= object
+ s
->object_size
;
821 if (s
->flags
& SLAB_RED_ZONE
) {
822 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
823 endobject
, val
, s
->inuse
- s
->object_size
))
826 if ((s
->flags
& SLAB_POISON
) && s
->object_size
< s
->inuse
) {
827 check_bytes_and_report(s
, page
, p
, "Alignment padding",
828 endobject
, POISON_INUSE
,
829 s
->inuse
- s
->object_size
);
833 if (s
->flags
& SLAB_POISON
) {
834 if (val
!= SLUB_RED_ACTIVE
&& (s
->flags
& __OBJECT_POISON
) &&
835 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
836 POISON_FREE
, s
->object_size
- 1) ||
837 !check_bytes_and_report(s
, page
, p
, "Poison",
838 p
+ s
->object_size
- 1, POISON_END
, 1)))
841 * check_pad_bytes cleans up on its own.
843 check_pad_bytes(s
, page
, p
);
846 if (!s
->offset
&& val
== SLUB_RED_ACTIVE
)
848 * Object and freepointer overlap. Cannot check
849 * freepointer while object is allocated.
853 /* Check free pointer validity */
854 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
855 object_err(s
, page
, p
, "Freepointer corrupt");
857 * No choice but to zap it and thus lose the remainder
858 * of the free objects in this slab. May cause
859 * another error because the object count is now wrong.
861 set_freepointer(s
, p
, NULL
);
867 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
871 VM_BUG_ON(!irqs_disabled());
873 if (!PageSlab(page
)) {
874 slab_err(s
, page
, "Not a valid slab page");
878 maxobj
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
879 if (page
->objects
> maxobj
) {
880 slab_err(s
, page
, "objects %u > max %u",
881 page
->objects
, maxobj
);
884 if (page
->inuse
> page
->objects
) {
885 slab_err(s
, page
, "inuse %u > max %u",
886 page
->inuse
, page
->objects
);
889 /* Slab_pad_check fixes things up after itself */
890 slab_pad_check(s
, page
);
895 * Determine if a certain object on a page is on the freelist. Must hold the
896 * slab lock to guarantee that the chains are in a consistent state.
898 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
906 while (fp
&& nr
<= page
->objects
) {
909 if (!check_valid_pointer(s
, page
, fp
)) {
911 object_err(s
, page
, object
,
912 "Freechain corrupt");
913 set_freepointer(s
, object
, NULL
);
915 slab_err(s
, page
, "Freepointer corrupt");
916 page
->freelist
= NULL
;
917 page
->inuse
= page
->objects
;
918 slab_fix(s
, "Freelist cleared");
924 fp
= get_freepointer(s
, object
);
928 max_objects
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
929 if (max_objects
> MAX_OBJS_PER_PAGE
)
930 max_objects
= MAX_OBJS_PER_PAGE
;
932 if (page
->objects
!= max_objects
) {
933 slab_err(s
, page
, "Wrong number of objects. Found %d but "
934 "should be %d", page
->objects
, max_objects
);
935 page
->objects
= max_objects
;
936 slab_fix(s
, "Number of objects adjusted.");
938 if (page
->inuse
!= page
->objects
- nr
) {
939 slab_err(s
, page
, "Wrong object count. Counter is %d but "
940 "counted were %d", page
->inuse
, page
->objects
- nr
);
941 page
->inuse
= page
->objects
- nr
;
942 slab_fix(s
, "Object count adjusted.");
944 return search
== NULL
;
947 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
,
950 if (s
->flags
& SLAB_TRACE
) {
951 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
953 alloc
? "alloc" : "free",
958 print_section("Object ", (void *)object
,
966 * Tracking of fully allocated slabs for debugging purposes.
968 static void add_full(struct kmem_cache
*s
,
969 struct kmem_cache_node
*n
, struct page
*page
)
971 if (!(s
->flags
& SLAB_STORE_USER
))
974 lockdep_assert_held(&n
->list_lock
);
975 list_add(&page
->lru
, &n
->full
);
978 static void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
, struct page
*page
)
980 if (!(s
->flags
& SLAB_STORE_USER
))
983 lockdep_assert_held(&n
->list_lock
);
984 list_del(&page
->lru
);
987 /* Tracking of the number of slabs for debugging purposes */
988 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
990 struct kmem_cache_node
*n
= get_node(s
, node
);
992 return atomic_long_read(&n
->nr_slabs
);
995 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
997 return atomic_long_read(&n
->nr_slabs
);
1000 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1002 struct kmem_cache_node
*n
= get_node(s
, node
);
1005 * May be called early in order to allocate a slab for the
1006 * kmem_cache_node structure. Solve the chicken-egg
1007 * dilemma by deferring the increment of the count during
1008 * bootstrap (see early_kmem_cache_node_alloc).
1011 atomic_long_inc(&n
->nr_slabs
);
1012 atomic_long_add(objects
, &n
->total_objects
);
1015 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1017 struct kmem_cache_node
*n
= get_node(s
, node
);
1019 atomic_long_dec(&n
->nr_slabs
);
1020 atomic_long_sub(objects
, &n
->total_objects
);
1023 /* Object debug checks for alloc/free paths */
1024 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
1027 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
1030 init_object(s
, object
, SLUB_RED_INACTIVE
);
1031 init_tracking(s
, object
);
1034 static noinline
int alloc_debug_processing(struct kmem_cache
*s
,
1036 void *object
, unsigned long addr
)
1038 if (!check_slab(s
, page
))
1041 if (!check_valid_pointer(s
, page
, object
)) {
1042 object_err(s
, page
, object
, "Freelist Pointer check fails");
1046 if (!check_object(s
, page
, object
, SLUB_RED_INACTIVE
))
1049 /* Success perform special debug activities for allocs */
1050 if (s
->flags
& SLAB_STORE_USER
)
1051 set_track(s
, object
, TRACK_ALLOC
, addr
);
1052 trace(s
, page
, object
, 1);
1053 init_object(s
, object
, SLUB_RED_ACTIVE
);
1057 if (PageSlab(page
)) {
1059 * If this is a slab page then lets do the best we can
1060 * to avoid issues in the future. Marking all objects
1061 * as used avoids touching the remaining objects.
1063 slab_fix(s
, "Marking all objects used");
1064 page
->inuse
= page
->objects
;
1065 page
->freelist
= NULL
;
1070 /* Supports checking bulk free of a constructed freelist */
1071 static noinline
struct kmem_cache_node
*free_debug_processing(
1072 struct kmem_cache
*s
, struct page
*page
,
1073 void *head
, void *tail
, int bulk_cnt
,
1074 unsigned long addr
, unsigned long *flags
)
1076 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1077 void *object
= head
;
1080 spin_lock_irqsave(&n
->list_lock
, *flags
);
1083 if (!check_slab(s
, page
))
1089 if (!check_valid_pointer(s
, page
, object
)) {
1090 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
1094 if (on_freelist(s
, page
, object
)) {
1095 object_err(s
, page
, object
, "Object already free");
1099 if (!check_object(s
, page
, object
, SLUB_RED_ACTIVE
))
1102 if (unlikely(s
!= page
->slab_cache
)) {
1103 if (!PageSlab(page
)) {
1104 slab_err(s
, page
, "Attempt to free object(0x%p) "
1105 "outside of slab", object
);
1106 } else if (!page
->slab_cache
) {
1107 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1111 object_err(s
, page
, object
,
1112 "page slab pointer corrupt.");
1116 if (s
->flags
& SLAB_STORE_USER
)
1117 set_track(s
, object
, TRACK_FREE
, addr
);
1118 trace(s
, page
, object
, 0);
1119 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1120 init_object(s
, object
, SLUB_RED_INACTIVE
);
1122 /* Reached end of constructed freelist yet? */
1123 if (object
!= tail
) {
1124 object
= get_freepointer(s
, object
);
1128 if (cnt
!= bulk_cnt
)
1129 slab_err(s
, page
, "Bulk freelist count(%d) invalid(%d)\n",
1134 * Keep node_lock to preserve integrity
1135 * until the object is actually freed
1141 spin_unlock_irqrestore(&n
->list_lock
, *flags
);
1142 slab_fix(s
, "Object at 0x%p not freed", object
);
1146 static int __init
setup_slub_debug(char *str
)
1148 slub_debug
= DEBUG_DEFAULT_FLAGS
;
1149 if (*str
++ != '=' || !*str
)
1151 * No options specified. Switch on full debugging.
1157 * No options but restriction on slabs. This means full
1158 * debugging for slabs matching a pattern.
1165 * Switch off all debugging measures.
1170 * Determine which debug features should be switched on
1172 for (; *str
&& *str
!= ','; str
++) {
1173 switch (tolower(*str
)) {
1175 slub_debug
|= SLAB_DEBUG_FREE
;
1178 slub_debug
|= SLAB_RED_ZONE
;
1181 slub_debug
|= SLAB_POISON
;
1184 slub_debug
|= SLAB_STORE_USER
;
1187 slub_debug
|= SLAB_TRACE
;
1190 slub_debug
|= SLAB_FAILSLAB
;
1194 * Avoid enabling debugging on caches if its minimum
1195 * order would increase as a result.
1197 disable_higher_order_debug
= 1;
1200 pr_err("slub_debug option '%c' unknown. skipped\n",
1207 slub_debug_slabs
= str
+ 1;
1212 __setup("slub_debug", setup_slub_debug
);
1214 unsigned long kmem_cache_flags(unsigned long object_size
,
1215 unsigned long flags
, const char *name
,
1216 void (*ctor
)(void *))
1219 * Enable debugging if selected on the kernel commandline.
1221 if (slub_debug
&& (!slub_debug_slabs
|| (name
&&
1222 !strncmp(slub_debug_slabs
, name
, strlen(slub_debug_slabs
)))))
1223 flags
|= slub_debug
;
1227 #else /* !CONFIG_SLUB_DEBUG */
1228 static inline void setup_object_debug(struct kmem_cache
*s
,
1229 struct page
*page
, void *object
) {}
1231 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1232 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1234 static inline struct kmem_cache_node
*free_debug_processing(
1235 struct kmem_cache
*s
, struct page
*page
,
1236 void *head
, void *tail
, int bulk_cnt
,
1237 unsigned long addr
, unsigned long *flags
) { return NULL
; }
1239 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1241 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1242 void *object
, u8 val
) { return 1; }
1243 static inline void add_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1244 struct page
*page
) {}
1245 static inline void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1246 struct page
*page
) {}
1247 unsigned long kmem_cache_flags(unsigned long object_size
,
1248 unsigned long flags
, const char *name
,
1249 void (*ctor
)(void *))
1253 #define slub_debug 0
1255 #define disable_higher_order_debug 0
1257 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1259 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1261 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
,
1263 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
,
1266 #endif /* CONFIG_SLUB_DEBUG */
1269 * Hooks for other subsystems that check memory allocations. In a typical
1270 * production configuration these hooks all should produce no code at all.
1272 static inline void kmalloc_large_node_hook(void *ptr
, size_t size
, gfp_t flags
)
1274 kmemleak_alloc(ptr
, size
, 1, flags
);
1275 kasan_kmalloc_large(ptr
, size
);
1278 static inline void kfree_hook(const void *x
)
1281 kasan_kfree_large(x
);
1284 static inline struct kmem_cache
*slab_pre_alloc_hook(struct kmem_cache
*s
,
1287 flags
&= gfp_allowed_mask
;
1288 lockdep_trace_alloc(flags
);
1289 might_sleep_if(gfpflags_allow_blocking(flags
));
1291 if (should_failslab(s
->object_size
, flags
, s
->flags
))
1294 return memcg_kmem_get_cache(s
, flags
);
1297 static inline void slab_post_alloc_hook(struct kmem_cache
*s
, gfp_t flags
,
1298 size_t size
, void **p
)
1302 flags
&= gfp_allowed_mask
;
1303 for (i
= 0; i
< size
; i
++) {
1304 void *object
= p
[i
];
1306 kmemcheck_slab_alloc(s
, flags
, object
, slab_ksize(s
));
1307 kmemleak_alloc_recursive(object
, s
->object_size
, 1,
1309 kasan_slab_alloc(s
, object
);
1311 memcg_kmem_put_cache(s
);
1314 static inline void slab_free_hook(struct kmem_cache
*s
, void *x
)
1316 kmemleak_free_recursive(x
, s
->flags
);
1319 * Trouble is that we may no longer disable interrupts in the fast path
1320 * So in order to make the debug calls that expect irqs to be
1321 * disabled we need to disable interrupts temporarily.
1323 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1325 unsigned long flags
;
1327 local_irq_save(flags
);
1328 kmemcheck_slab_free(s
, x
, s
->object_size
);
1329 debug_check_no_locks_freed(x
, s
->object_size
);
1330 local_irq_restore(flags
);
1333 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
1334 debug_check_no_obj_freed(x
, s
->object_size
);
1336 kasan_slab_free(s
, x
);
1339 static inline void slab_free_freelist_hook(struct kmem_cache
*s
,
1340 void *head
, void *tail
)
1343 * Compiler cannot detect this function can be removed if slab_free_hook()
1344 * evaluates to nothing. Thus, catch all relevant config debug options here.
1346 #if defined(CONFIG_KMEMCHECK) || \
1347 defined(CONFIG_LOCKDEP) || \
1348 defined(CONFIG_DEBUG_KMEMLEAK) || \
1349 defined(CONFIG_DEBUG_OBJECTS_FREE) || \
1350 defined(CONFIG_KASAN)
1352 void *object
= head
;
1353 void *tail_obj
= tail
? : head
;
1356 slab_free_hook(s
, object
);
1357 } while ((object
!= tail_obj
) &&
1358 (object
= get_freepointer(s
, object
)));
1362 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1365 setup_object_debug(s
, page
, object
);
1366 if (unlikely(s
->ctor
)) {
1367 kasan_unpoison_object_data(s
, object
);
1369 kasan_poison_object_data(s
, object
);
1374 * Slab allocation and freeing
1376 static inline struct page
*alloc_slab_page(struct kmem_cache
*s
,
1377 gfp_t flags
, int node
, struct kmem_cache_order_objects oo
)
1380 int order
= oo_order(oo
);
1382 flags
|= __GFP_NOTRACK
;
1384 if (node
== NUMA_NO_NODE
)
1385 page
= alloc_pages(flags
, order
);
1387 page
= __alloc_pages_node(node
, flags
, order
);
1389 if (page
&& memcg_charge_slab(page
, flags
, order
, s
)) {
1390 __free_pages(page
, order
);
1397 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1400 struct kmem_cache_order_objects oo
= s
->oo
;
1405 flags
&= gfp_allowed_mask
;
1407 if (gfpflags_allow_blocking(flags
))
1410 flags
|= s
->allocflags
;
1413 * Let the initial higher-order allocation fail under memory pressure
1414 * so we fall-back to the minimum order allocation.
1416 alloc_gfp
= (flags
| __GFP_NOWARN
| __GFP_NORETRY
) & ~__GFP_NOFAIL
;
1417 if ((alloc_gfp
& __GFP_DIRECT_RECLAIM
) && oo_order(oo
) > oo_order(s
->min
))
1418 alloc_gfp
= (alloc_gfp
| __GFP_NOMEMALLOC
) & ~__GFP_DIRECT_RECLAIM
;
1420 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1421 if (unlikely(!page
)) {
1425 * Allocation may have failed due to fragmentation.
1426 * Try a lower order alloc if possible
1428 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1429 if (unlikely(!page
))
1431 stat(s
, ORDER_FALLBACK
);
1434 if (kmemcheck_enabled
&&
1435 !(s
->flags
& (SLAB_NOTRACK
| DEBUG_DEFAULT_FLAGS
))) {
1436 int pages
= 1 << oo_order(oo
);
1438 kmemcheck_alloc_shadow(page
, oo_order(oo
), alloc_gfp
, node
);
1441 * Objects from caches that have a constructor don't get
1442 * cleared when they're allocated, so we need to do it here.
1445 kmemcheck_mark_uninitialized_pages(page
, pages
);
1447 kmemcheck_mark_unallocated_pages(page
, pages
);
1450 page
->objects
= oo_objects(oo
);
1452 order
= compound_order(page
);
1453 page
->slab_cache
= s
;
1454 __SetPageSlab(page
);
1455 if (page_is_pfmemalloc(page
))
1456 SetPageSlabPfmemalloc(page
);
1458 start
= page_address(page
);
1460 if (unlikely(s
->flags
& SLAB_POISON
))
1461 memset(start
, POISON_INUSE
, PAGE_SIZE
<< order
);
1463 kasan_poison_slab(page
);
1465 for_each_object_idx(p
, idx
, s
, start
, page
->objects
) {
1466 setup_object(s
, page
, p
);
1467 if (likely(idx
< page
->objects
))
1468 set_freepointer(s
, p
, p
+ s
->size
);
1470 set_freepointer(s
, p
, NULL
);
1473 page
->freelist
= start
;
1474 page
->inuse
= page
->objects
;
1478 if (gfpflags_allow_blocking(flags
))
1479 local_irq_disable();
1483 mod_zone_page_state(page_zone(page
),
1484 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1485 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1488 inc_slabs_node(s
, page_to_nid(page
), page
->objects
);
1493 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1495 if (unlikely(flags
& GFP_SLAB_BUG_MASK
)) {
1496 pr_emerg("gfp: %u\n", flags
& GFP_SLAB_BUG_MASK
);
1500 return allocate_slab(s
,
1501 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1504 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1506 int order
= compound_order(page
);
1507 int pages
= 1 << order
;
1509 if (kmem_cache_debug(s
)) {
1512 slab_pad_check(s
, page
);
1513 for_each_object(p
, s
, page_address(page
),
1515 check_object(s
, page
, p
, SLUB_RED_INACTIVE
);
1518 kmemcheck_free_shadow(page
, compound_order(page
));
1520 mod_zone_page_state(page_zone(page
),
1521 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1522 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1525 __ClearPageSlabPfmemalloc(page
);
1526 __ClearPageSlab(page
);
1528 page_mapcount_reset(page
);
1529 if (current
->reclaim_state
)
1530 current
->reclaim_state
->reclaimed_slab
+= pages
;
1531 __free_kmem_pages(page
, order
);
1534 #define need_reserve_slab_rcu \
1535 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1537 static void rcu_free_slab(struct rcu_head
*h
)
1541 if (need_reserve_slab_rcu
)
1542 page
= virt_to_head_page(h
);
1544 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1546 __free_slab(page
->slab_cache
, page
);
1549 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1551 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1552 struct rcu_head
*head
;
1554 if (need_reserve_slab_rcu
) {
1555 int order
= compound_order(page
);
1556 int offset
= (PAGE_SIZE
<< order
) - s
->reserved
;
1558 VM_BUG_ON(s
->reserved
!= sizeof(*head
));
1559 head
= page_address(page
) + offset
;
1561 head
= &page
->rcu_head
;
1564 call_rcu(head
, rcu_free_slab
);
1566 __free_slab(s
, page
);
1569 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1571 dec_slabs_node(s
, page_to_nid(page
), page
->objects
);
1576 * Management of partially allocated slabs.
1579 __add_partial(struct kmem_cache_node
*n
, struct page
*page
, int tail
)
1582 if (tail
== DEACTIVATE_TO_TAIL
)
1583 list_add_tail(&page
->lru
, &n
->partial
);
1585 list_add(&page
->lru
, &n
->partial
);
1588 static inline void add_partial(struct kmem_cache_node
*n
,
1589 struct page
*page
, int tail
)
1591 lockdep_assert_held(&n
->list_lock
);
1592 __add_partial(n
, page
, tail
);
1595 static inline void remove_partial(struct kmem_cache_node
*n
,
1598 lockdep_assert_held(&n
->list_lock
);
1599 list_del(&page
->lru
);
1604 * Remove slab from the partial list, freeze it and
1605 * return the pointer to the freelist.
1607 * Returns a list of objects or NULL if it fails.
1609 static inline void *acquire_slab(struct kmem_cache
*s
,
1610 struct kmem_cache_node
*n
, struct page
*page
,
1611 int mode
, int *objects
)
1614 unsigned long counters
;
1617 lockdep_assert_held(&n
->list_lock
);
1620 * Zap the freelist and set the frozen bit.
1621 * The old freelist is the list of objects for the
1622 * per cpu allocation list.
1624 freelist
= page
->freelist
;
1625 counters
= page
->counters
;
1626 new.counters
= counters
;
1627 *objects
= new.objects
- new.inuse
;
1629 new.inuse
= page
->objects
;
1630 new.freelist
= NULL
;
1632 new.freelist
= freelist
;
1635 VM_BUG_ON(new.frozen
);
1638 if (!__cmpxchg_double_slab(s
, page
,
1640 new.freelist
, new.counters
,
1644 remove_partial(n
, page
);
1649 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
);
1650 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
);
1653 * Try to allocate a partial slab from a specific node.
1655 static void *get_partial_node(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1656 struct kmem_cache_cpu
*c
, gfp_t flags
)
1658 struct page
*page
, *page2
;
1659 void *object
= NULL
;
1664 * Racy check. If we mistakenly see no partial slabs then we
1665 * just allocate an empty slab. If we mistakenly try to get a
1666 * partial slab and there is none available then get_partials()
1669 if (!n
|| !n
->nr_partial
)
1672 spin_lock(&n
->list_lock
);
1673 list_for_each_entry_safe(page
, page2
, &n
->partial
, lru
) {
1676 if (!pfmemalloc_match(page
, flags
))
1679 t
= acquire_slab(s
, n
, page
, object
== NULL
, &objects
);
1683 available
+= objects
;
1686 stat(s
, ALLOC_FROM_PARTIAL
);
1689 put_cpu_partial(s
, page
, 0);
1690 stat(s
, CPU_PARTIAL_NODE
);
1692 if (!kmem_cache_has_cpu_partial(s
)
1693 || available
> s
->cpu_partial
/ 2)
1697 spin_unlock(&n
->list_lock
);
1702 * Get a page from somewhere. Search in increasing NUMA distances.
1704 static void *get_any_partial(struct kmem_cache
*s
, gfp_t flags
,
1705 struct kmem_cache_cpu
*c
)
1708 struct zonelist
*zonelist
;
1711 enum zone_type high_zoneidx
= gfp_zone(flags
);
1713 unsigned int cpuset_mems_cookie
;
1716 * The defrag ratio allows a configuration of the tradeoffs between
1717 * inter node defragmentation and node local allocations. A lower
1718 * defrag_ratio increases the tendency to do local allocations
1719 * instead of attempting to obtain partial slabs from other nodes.
1721 * If the defrag_ratio is set to 0 then kmalloc() always
1722 * returns node local objects. If the ratio is higher then kmalloc()
1723 * may return off node objects because partial slabs are obtained
1724 * from other nodes and filled up.
1726 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1727 * defrag_ratio = 1000) then every (well almost) allocation will
1728 * first attempt to defrag slab caches on other nodes. This means
1729 * scanning over all nodes to look for partial slabs which may be
1730 * expensive if we do it every time we are trying to find a slab
1731 * with available objects.
1733 if (!s
->remote_node_defrag_ratio
||
1734 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1738 cpuset_mems_cookie
= read_mems_allowed_begin();
1739 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
1740 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
1741 struct kmem_cache_node
*n
;
1743 n
= get_node(s
, zone_to_nid(zone
));
1745 if (n
&& cpuset_zone_allowed(zone
, flags
) &&
1746 n
->nr_partial
> s
->min_partial
) {
1747 object
= get_partial_node(s
, n
, c
, flags
);
1750 * Don't check read_mems_allowed_retry()
1751 * here - if mems_allowed was updated in
1752 * parallel, that was a harmless race
1753 * between allocation and the cpuset
1760 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1766 * Get a partial page, lock it and return it.
1768 static void *get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
,
1769 struct kmem_cache_cpu
*c
)
1772 int searchnode
= node
;
1774 if (node
== NUMA_NO_NODE
)
1775 searchnode
= numa_mem_id();
1776 else if (!node_present_pages(node
))
1777 searchnode
= node_to_mem_node(node
);
1779 object
= get_partial_node(s
, get_node(s
, searchnode
), c
, flags
);
1780 if (object
|| node
!= NUMA_NO_NODE
)
1783 return get_any_partial(s
, flags
, c
);
1786 #ifdef CONFIG_PREEMPT
1788 * Calculate the next globally unique transaction for disambiguiation
1789 * during cmpxchg. The transactions start with the cpu number and are then
1790 * incremented by CONFIG_NR_CPUS.
1792 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1795 * No preemption supported therefore also no need to check for
1801 static inline unsigned long next_tid(unsigned long tid
)
1803 return tid
+ TID_STEP
;
1806 static inline unsigned int tid_to_cpu(unsigned long tid
)
1808 return tid
% TID_STEP
;
1811 static inline unsigned long tid_to_event(unsigned long tid
)
1813 return tid
/ TID_STEP
;
1816 static inline unsigned int init_tid(int cpu
)
1821 static inline void note_cmpxchg_failure(const char *n
,
1822 const struct kmem_cache
*s
, unsigned long tid
)
1824 #ifdef SLUB_DEBUG_CMPXCHG
1825 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
1827 pr_info("%s %s: cmpxchg redo ", n
, s
->name
);
1829 #ifdef CONFIG_PREEMPT
1830 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
1831 pr_warn("due to cpu change %d -> %d\n",
1832 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
1835 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
1836 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1837 tid_to_event(tid
), tid_to_event(actual_tid
));
1839 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1840 actual_tid
, tid
, next_tid(tid
));
1842 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
1845 static void init_kmem_cache_cpus(struct kmem_cache
*s
)
1849 for_each_possible_cpu(cpu
)
1850 per_cpu_ptr(s
->cpu_slab
, cpu
)->tid
= init_tid(cpu
);
1854 * Remove the cpu slab
1856 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
,
1859 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
1860 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1862 enum slab_modes l
= M_NONE
, m
= M_NONE
;
1864 int tail
= DEACTIVATE_TO_HEAD
;
1868 if (page
->freelist
) {
1869 stat(s
, DEACTIVATE_REMOTE_FREES
);
1870 tail
= DEACTIVATE_TO_TAIL
;
1874 * Stage one: Free all available per cpu objects back
1875 * to the page freelist while it is still frozen. Leave the
1878 * There is no need to take the list->lock because the page
1881 while (freelist
&& (nextfree
= get_freepointer(s
, freelist
))) {
1883 unsigned long counters
;
1886 prior
= page
->freelist
;
1887 counters
= page
->counters
;
1888 set_freepointer(s
, freelist
, prior
);
1889 new.counters
= counters
;
1891 VM_BUG_ON(!new.frozen
);
1893 } while (!__cmpxchg_double_slab(s
, page
,
1895 freelist
, new.counters
,
1896 "drain percpu freelist"));
1898 freelist
= nextfree
;
1902 * Stage two: Ensure that the page is unfrozen while the
1903 * list presence reflects the actual number of objects
1906 * We setup the list membership and then perform a cmpxchg
1907 * with the count. If there is a mismatch then the page
1908 * is not unfrozen but the page is on the wrong list.
1910 * Then we restart the process which may have to remove
1911 * the page from the list that we just put it on again
1912 * because the number of objects in the slab may have
1917 old
.freelist
= page
->freelist
;
1918 old
.counters
= page
->counters
;
1919 VM_BUG_ON(!old
.frozen
);
1921 /* Determine target state of the slab */
1922 new.counters
= old
.counters
;
1925 set_freepointer(s
, freelist
, old
.freelist
);
1926 new.freelist
= freelist
;
1928 new.freelist
= old
.freelist
;
1932 if (!new.inuse
&& n
->nr_partial
>= s
->min_partial
)
1934 else if (new.freelist
) {
1939 * Taking the spinlock removes the possiblity
1940 * that acquire_slab() will see a slab page that
1943 spin_lock(&n
->list_lock
);
1947 if (kmem_cache_debug(s
) && !lock
) {
1950 * This also ensures that the scanning of full
1951 * slabs from diagnostic functions will not see
1954 spin_lock(&n
->list_lock
);
1962 remove_partial(n
, page
);
1964 else if (l
== M_FULL
)
1966 remove_full(s
, n
, page
);
1968 if (m
== M_PARTIAL
) {
1970 add_partial(n
, page
, tail
);
1973 } else if (m
== M_FULL
) {
1975 stat(s
, DEACTIVATE_FULL
);
1976 add_full(s
, n
, page
);
1982 if (!__cmpxchg_double_slab(s
, page
,
1983 old
.freelist
, old
.counters
,
1984 new.freelist
, new.counters
,
1989 spin_unlock(&n
->list_lock
);
1992 stat(s
, DEACTIVATE_EMPTY
);
1993 discard_slab(s
, page
);
1999 * Unfreeze all the cpu partial slabs.
2001 * This function must be called with interrupts disabled
2002 * for the cpu using c (or some other guarantee must be there
2003 * to guarantee no concurrent accesses).
2005 static void unfreeze_partials(struct kmem_cache
*s
,
2006 struct kmem_cache_cpu
*c
)
2008 #ifdef CONFIG_SLUB_CPU_PARTIAL
2009 struct kmem_cache_node
*n
= NULL
, *n2
= NULL
;
2010 struct page
*page
, *discard_page
= NULL
;
2012 while ((page
= c
->partial
)) {
2016 c
->partial
= page
->next
;
2018 n2
= get_node(s
, page_to_nid(page
));
2021 spin_unlock(&n
->list_lock
);
2024 spin_lock(&n
->list_lock
);
2029 old
.freelist
= page
->freelist
;
2030 old
.counters
= page
->counters
;
2031 VM_BUG_ON(!old
.frozen
);
2033 new.counters
= old
.counters
;
2034 new.freelist
= old
.freelist
;
2038 } while (!__cmpxchg_double_slab(s
, page
,
2039 old
.freelist
, old
.counters
,
2040 new.freelist
, new.counters
,
2041 "unfreezing slab"));
2043 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
)) {
2044 page
->next
= discard_page
;
2045 discard_page
= page
;
2047 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2048 stat(s
, FREE_ADD_PARTIAL
);
2053 spin_unlock(&n
->list_lock
);
2055 while (discard_page
) {
2056 page
= discard_page
;
2057 discard_page
= discard_page
->next
;
2059 stat(s
, DEACTIVATE_EMPTY
);
2060 discard_slab(s
, page
);
2067 * Put a page that was just frozen (in __slab_free) into a partial page
2068 * slot if available. This is done without interrupts disabled and without
2069 * preemption disabled. The cmpxchg is racy and may put the partial page
2070 * onto a random cpus partial slot.
2072 * If we did not find a slot then simply move all the partials to the
2073 * per node partial list.
2075 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
)
2077 #ifdef CONFIG_SLUB_CPU_PARTIAL
2078 struct page
*oldpage
;
2086 oldpage
= this_cpu_read(s
->cpu_slab
->partial
);
2089 pobjects
= oldpage
->pobjects
;
2090 pages
= oldpage
->pages
;
2091 if (drain
&& pobjects
> s
->cpu_partial
) {
2092 unsigned long flags
;
2094 * partial array is full. Move the existing
2095 * set to the per node partial list.
2097 local_irq_save(flags
);
2098 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2099 local_irq_restore(flags
);
2103 stat(s
, CPU_PARTIAL_DRAIN
);
2108 pobjects
+= page
->objects
- page
->inuse
;
2110 page
->pages
= pages
;
2111 page
->pobjects
= pobjects
;
2112 page
->next
= oldpage
;
2114 } while (this_cpu_cmpxchg(s
->cpu_slab
->partial
, oldpage
, page
)
2116 if (unlikely(!s
->cpu_partial
)) {
2117 unsigned long flags
;
2119 local_irq_save(flags
);
2120 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2121 local_irq_restore(flags
);
2127 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
2129 stat(s
, CPUSLAB_FLUSH
);
2130 deactivate_slab(s
, c
->page
, c
->freelist
);
2132 c
->tid
= next_tid(c
->tid
);
2140 * Called from IPI handler with interrupts disabled.
2142 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
2144 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2150 unfreeze_partials(s
, c
);
2154 static void flush_cpu_slab(void *d
)
2156 struct kmem_cache
*s
= d
;
2158 __flush_cpu_slab(s
, smp_processor_id());
2161 static bool has_cpu_slab(int cpu
, void *info
)
2163 struct kmem_cache
*s
= info
;
2164 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2166 return c
->page
|| c
->partial
;
2169 static void flush_all(struct kmem_cache
*s
)
2171 on_each_cpu_cond(has_cpu_slab
, flush_cpu_slab
, s
, 1, GFP_ATOMIC
);
2175 * Check if the objects in a per cpu structure fit numa
2176 * locality expectations.
2178 static inline int node_match(struct page
*page
, int node
)
2181 if (!page
|| (node
!= NUMA_NO_NODE
&& page_to_nid(page
) != node
))
2187 #ifdef CONFIG_SLUB_DEBUG
2188 static int count_free(struct page
*page
)
2190 return page
->objects
- page
->inuse
;
2193 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
2195 return atomic_long_read(&n
->total_objects
);
2197 #endif /* CONFIG_SLUB_DEBUG */
2199 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2200 static unsigned long count_partial(struct kmem_cache_node
*n
,
2201 int (*get_count
)(struct page
*))
2203 unsigned long flags
;
2204 unsigned long x
= 0;
2207 spin_lock_irqsave(&n
->list_lock
, flags
);
2208 list_for_each_entry(page
, &n
->partial
, lru
)
2209 x
+= get_count(page
);
2210 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2213 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2215 static noinline
void
2216 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
2218 #ifdef CONFIG_SLUB_DEBUG
2219 static DEFINE_RATELIMIT_STATE(slub_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2220 DEFAULT_RATELIMIT_BURST
);
2222 struct kmem_cache_node
*n
;
2224 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slub_oom_rs
))
2227 pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2229 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2230 s
->name
, s
->object_size
, s
->size
, oo_order(s
->oo
),
2233 if (oo_order(s
->min
) > get_order(s
->object_size
))
2234 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2237 for_each_kmem_cache_node(s
, node
, n
) {
2238 unsigned long nr_slabs
;
2239 unsigned long nr_objs
;
2240 unsigned long nr_free
;
2242 nr_free
= count_partial(n
, count_free
);
2243 nr_slabs
= node_nr_slabs(n
);
2244 nr_objs
= node_nr_objs(n
);
2246 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2247 node
, nr_slabs
, nr_objs
, nr_free
);
2252 static inline void *new_slab_objects(struct kmem_cache
*s
, gfp_t flags
,
2253 int node
, struct kmem_cache_cpu
**pc
)
2256 struct kmem_cache_cpu
*c
= *pc
;
2259 freelist
= get_partial(s
, flags
, node
, c
);
2264 page
= new_slab(s
, flags
, node
);
2266 c
= raw_cpu_ptr(s
->cpu_slab
);
2271 * No other reference to the page yet so we can
2272 * muck around with it freely without cmpxchg
2274 freelist
= page
->freelist
;
2275 page
->freelist
= NULL
;
2277 stat(s
, ALLOC_SLAB
);
2286 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
)
2288 if (unlikely(PageSlabPfmemalloc(page
)))
2289 return gfp_pfmemalloc_allowed(gfpflags
);
2295 * Check the page->freelist of a page and either transfer the freelist to the
2296 * per cpu freelist or deactivate the page.
2298 * The page is still frozen if the return value is not NULL.
2300 * If this function returns NULL then the page has been unfrozen.
2302 * This function must be called with interrupt disabled.
2304 static inline void *get_freelist(struct kmem_cache
*s
, struct page
*page
)
2307 unsigned long counters
;
2311 freelist
= page
->freelist
;
2312 counters
= page
->counters
;
2314 new.counters
= counters
;
2315 VM_BUG_ON(!new.frozen
);
2317 new.inuse
= page
->objects
;
2318 new.frozen
= freelist
!= NULL
;
2320 } while (!__cmpxchg_double_slab(s
, page
,
2329 * Slow path. The lockless freelist is empty or we need to perform
2332 * Processing is still very fast if new objects have been freed to the
2333 * regular freelist. In that case we simply take over the regular freelist
2334 * as the lockless freelist and zap the regular freelist.
2336 * If that is not working then we fall back to the partial lists. We take the
2337 * first element of the freelist as the object to allocate now and move the
2338 * rest of the freelist to the lockless freelist.
2340 * And if we were unable to get a new slab from the partial slab lists then
2341 * we need to allocate a new slab. This is the slowest path since it involves
2342 * a call to the page allocator and the setup of a new slab.
2344 * Version of __slab_alloc to use when we know that interrupts are
2345 * already disabled (which is the case for bulk allocation).
2347 static void *___slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2348 unsigned long addr
, struct kmem_cache_cpu
*c
)
2358 if (unlikely(!node_match(page
, node
))) {
2359 int searchnode
= node
;
2361 if (node
!= NUMA_NO_NODE
&& !node_present_pages(node
))
2362 searchnode
= node_to_mem_node(node
);
2364 if (unlikely(!node_match(page
, searchnode
))) {
2365 stat(s
, ALLOC_NODE_MISMATCH
);
2366 deactivate_slab(s
, page
, c
->freelist
);
2374 * By rights, we should be searching for a slab page that was
2375 * PFMEMALLOC but right now, we are losing the pfmemalloc
2376 * information when the page leaves the per-cpu allocator
2378 if (unlikely(!pfmemalloc_match(page
, gfpflags
))) {
2379 deactivate_slab(s
, page
, c
->freelist
);
2385 /* must check again c->freelist in case of cpu migration or IRQ */
2386 freelist
= c
->freelist
;
2390 freelist
= get_freelist(s
, page
);
2394 stat(s
, DEACTIVATE_BYPASS
);
2398 stat(s
, ALLOC_REFILL
);
2402 * freelist is pointing to the list of objects to be used.
2403 * page is pointing to the page from which the objects are obtained.
2404 * That page must be frozen for per cpu allocations to work.
2406 VM_BUG_ON(!c
->page
->frozen
);
2407 c
->freelist
= get_freepointer(s
, freelist
);
2408 c
->tid
= next_tid(c
->tid
);
2414 page
= c
->page
= c
->partial
;
2415 c
->partial
= page
->next
;
2416 stat(s
, CPU_PARTIAL_ALLOC
);
2421 freelist
= new_slab_objects(s
, gfpflags
, node
, &c
);
2423 if (unlikely(!freelist
)) {
2424 slab_out_of_memory(s
, gfpflags
, node
);
2429 if (likely(!kmem_cache_debug(s
) && pfmemalloc_match(page
, gfpflags
)))
2432 /* Only entered in the debug case */
2433 if (kmem_cache_debug(s
) &&
2434 !alloc_debug_processing(s
, page
, freelist
, addr
))
2435 goto new_slab
; /* Slab failed checks. Next slab needed */
2437 deactivate_slab(s
, page
, get_freepointer(s
, freelist
));
2444 * Another one that disabled interrupt and compensates for possible
2445 * cpu changes by refetching the per cpu area pointer.
2447 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2448 unsigned long addr
, struct kmem_cache_cpu
*c
)
2451 unsigned long flags
;
2453 local_irq_save(flags
);
2454 #ifdef CONFIG_PREEMPT
2456 * We may have been preempted and rescheduled on a different
2457 * cpu before disabling interrupts. Need to reload cpu area
2460 c
= this_cpu_ptr(s
->cpu_slab
);
2463 p
= ___slab_alloc(s
, gfpflags
, node
, addr
, c
);
2464 local_irq_restore(flags
);
2469 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2470 * have the fastpath folded into their functions. So no function call
2471 * overhead for requests that can be satisfied on the fastpath.
2473 * The fastpath works by first checking if the lockless freelist can be used.
2474 * If not then __slab_alloc is called for slow processing.
2476 * Otherwise we can simply pick the next object from the lockless free list.
2478 static __always_inline
void *slab_alloc_node(struct kmem_cache
*s
,
2479 gfp_t gfpflags
, int node
, unsigned long addr
)
2482 struct kmem_cache_cpu
*c
;
2486 s
= slab_pre_alloc_hook(s
, gfpflags
);
2491 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2492 * enabled. We may switch back and forth between cpus while
2493 * reading from one cpu area. That does not matter as long
2494 * as we end up on the original cpu again when doing the cmpxchg.
2496 * We should guarantee that tid and kmem_cache are retrieved on
2497 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2498 * to check if it is matched or not.
2501 tid
= this_cpu_read(s
->cpu_slab
->tid
);
2502 c
= raw_cpu_ptr(s
->cpu_slab
);
2503 } while (IS_ENABLED(CONFIG_PREEMPT
) &&
2504 unlikely(tid
!= READ_ONCE(c
->tid
)));
2507 * Irqless object alloc/free algorithm used here depends on sequence
2508 * of fetching cpu_slab's data. tid should be fetched before anything
2509 * on c to guarantee that object and page associated with previous tid
2510 * won't be used with current tid. If we fetch tid first, object and
2511 * page could be one associated with next tid and our alloc/free
2512 * request will be failed. In this case, we will retry. So, no problem.
2517 * The transaction ids are globally unique per cpu and per operation on
2518 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2519 * occurs on the right processor and that there was no operation on the
2520 * linked list in between.
2523 object
= c
->freelist
;
2525 if (unlikely(!object
|| !node_match(page
, node
))) {
2526 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
2527 stat(s
, ALLOC_SLOWPATH
);
2529 void *next_object
= get_freepointer_safe(s
, object
);
2532 * The cmpxchg will only match if there was no additional
2533 * operation and if we are on the right processor.
2535 * The cmpxchg does the following atomically (without lock
2537 * 1. Relocate first pointer to the current per cpu area.
2538 * 2. Verify that tid and freelist have not been changed
2539 * 3. If they were not changed replace tid and freelist
2541 * Since this is without lock semantics the protection is only
2542 * against code executing on this cpu *not* from access by
2545 if (unlikely(!this_cpu_cmpxchg_double(
2546 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2548 next_object
, next_tid(tid
)))) {
2550 note_cmpxchg_failure("slab_alloc", s
, tid
);
2553 prefetch_freepointer(s
, next_object
);
2554 stat(s
, ALLOC_FASTPATH
);
2557 if (unlikely(gfpflags
& __GFP_ZERO
) && object
)
2558 memset(object
, 0, s
->object_size
);
2560 slab_post_alloc_hook(s
, gfpflags
, 1, &object
);
2565 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
2566 gfp_t gfpflags
, unsigned long addr
)
2568 return slab_alloc_node(s
, gfpflags
, NUMA_NO_NODE
, addr
);
2571 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
2573 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2575 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->object_size
,
2580 EXPORT_SYMBOL(kmem_cache_alloc
);
2582 #ifdef CONFIG_TRACING
2583 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
2585 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2586 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
2587 kasan_kmalloc(s
, ret
, size
);
2590 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
2594 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
2596 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2598 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
2599 s
->object_size
, s
->size
, gfpflags
, node
);
2603 EXPORT_SYMBOL(kmem_cache_alloc_node
);
2605 #ifdef CONFIG_TRACING
2606 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
2608 int node
, size_t size
)
2610 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2612 trace_kmalloc_node(_RET_IP_
, ret
,
2613 size
, s
->size
, gfpflags
, node
);
2615 kasan_kmalloc(s
, ret
, size
);
2618 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
2623 * Slow path handling. This may still be called frequently since objects
2624 * have a longer lifetime than the cpu slabs in most processing loads.
2626 * So we still attempt to reduce cache line usage. Just take the slab
2627 * lock and free the item. If there is no additional partial page
2628 * handling required then we can return immediately.
2630 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
2631 void *head
, void *tail
, int cnt
,
2638 unsigned long counters
;
2639 struct kmem_cache_node
*n
= NULL
;
2640 unsigned long uninitialized_var(flags
);
2642 stat(s
, FREE_SLOWPATH
);
2644 if (kmem_cache_debug(s
) &&
2645 !(n
= free_debug_processing(s
, page
, head
, tail
, cnt
,
2651 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2654 prior
= page
->freelist
;
2655 counters
= page
->counters
;
2656 set_freepointer(s
, tail
, prior
);
2657 new.counters
= counters
;
2658 was_frozen
= new.frozen
;
2660 if ((!new.inuse
|| !prior
) && !was_frozen
) {
2662 if (kmem_cache_has_cpu_partial(s
) && !prior
) {
2665 * Slab was on no list before and will be
2667 * We can defer the list move and instead
2672 } else { /* Needs to be taken off a list */
2674 n
= get_node(s
, page_to_nid(page
));
2676 * Speculatively acquire the list_lock.
2677 * If the cmpxchg does not succeed then we may
2678 * drop the list_lock without any processing.
2680 * Otherwise the list_lock will synchronize with
2681 * other processors updating the list of slabs.
2683 spin_lock_irqsave(&n
->list_lock
, flags
);
2688 } while (!cmpxchg_double_slab(s
, page
,
2696 * If we just froze the page then put it onto the
2697 * per cpu partial list.
2699 if (new.frozen
&& !was_frozen
) {
2700 put_cpu_partial(s
, page
, 1);
2701 stat(s
, CPU_PARTIAL_FREE
);
2704 * The list lock was not taken therefore no list
2705 * activity can be necessary.
2708 stat(s
, FREE_FROZEN
);
2712 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
))
2716 * Objects left in the slab. If it was not on the partial list before
2719 if (!kmem_cache_has_cpu_partial(s
) && unlikely(!prior
)) {
2720 if (kmem_cache_debug(s
))
2721 remove_full(s
, n
, page
);
2722 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2723 stat(s
, FREE_ADD_PARTIAL
);
2725 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2731 * Slab on the partial list.
2733 remove_partial(n
, page
);
2734 stat(s
, FREE_REMOVE_PARTIAL
);
2736 /* Slab must be on the full list */
2737 remove_full(s
, n
, page
);
2740 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2742 discard_slab(s
, page
);
2746 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2747 * can perform fastpath freeing without additional function calls.
2749 * The fastpath is only possible if we are freeing to the current cpu slab
2750 * of this processor. This typically the case if we have just allocated
2753 * If fastpath is not possible then fall back to __slab_free where we deal
2754 * with all sorts of special processing.
2756 * Bulk free of a freelist with several objects (all pointing to the
2757 * same page) possible by specifying head and tail ptr, plus objects
2758 * count (cnt). Bulk free indicated by tail pointer being set.
2760 static __always_inline
void slab_free(struct kmem_cache
*s
, struct page
*page
,
2761 void *head
, void *tail
, int cnt
,
2764 void *tail_obj
= tail
? : head
;
2765 struct kmem_cache_cpu
*c
;
2768 slab_free_freelist_hook(s
, head
, tail
);
2772 * Determine the currently cpus per cpu slab.
2773 * The cpu may change afterward. However that does not matter since
2774 * data is retrieved via this pointer. If we are on the same cpu
2775 * during the cmpxchg then the free will succeed.
2778 tid
= this_cpu_read(s
->cpu_slab
->tid
);
2779 c
= raw_cpu_ptr(s
->cpu_slab
);
2780 } while (IS_ENABLED(CONFIG_PREEMPT
) &&
2781 unlikely(tid
!= READ_ONCE(c
->tid
)));
2783 /* Same with comment on barrier() in slab_alloc_node() */
2786 if (likely(page
== c
->page
)) {
2787 set_freepointer(s
, tail_obj
, c
->freelist
);
2789 if (unlikely(!this_cpu_cmpxchg_double(
2790 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2792 head
, next_tid(tid
)))) {
2794 note_cmpxchg_failure("slab_free", s
, tid
);
2797 stat(s
, FREE_FASTPATH
);
2799 __slab_free(s
, page
, head
, tail_obj
, cnt
, addr
);
2803 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
2805 s
= cache_from_obj(s
, x
);
2808 slab_free(s
, virt_to_head_page(x
), x
, NULL
, 1, _RET_IP_
);
2809 trace_kmem_cache_free(_RET_IP_
, x
);
2811 EXPORT_SYMBOL(kmem_cache_free
);
2813 struct detached_freelist
{
2821 * This function progressively scans the array with free objects (with
2822 * a limited look ahead) and extract objects belonging to the same
2823 * page. It builds a detached freelist directly within the given
2824 * page/objects. This can happen without any need for
2825 * synchronization, because the objects are owned by running process.
2826 * The freelist is build up as a single linked list in the objects.
2827 * The idea is, that this detached freelist can then be bulk
2828 * transferred to the real freelist(s), but only requiring a single
2829 * synchronization primitive. Look ahead in the array is limited due
2830 * to performance reasons.
2832 static int build_detached_freelist(struct kmem_cache
*s
, size_t size
,
2833 void **p
, struct detached_freelist
*df
)
2835 size_t first_skipped_index
= 0;
2839 /* Always re-init detached_freelist */
2844 } while (!object
&& size
);
2849 /* Start new detached freelist */
2850 set_freepointer(s
, object
, NULL
);
2851 df
->page
= virt_to_head_page(object
);
2853 df
->freelist
= object
;
2854 p
[size
] = NULL
; /* mark object processed */
2860 continue; /* Skip processed objects */
2862 /* df->page is always set at this point */
2863 if (df
->page
== virt_to_head_page(object
)) {
2864 /* Opportunity build freelist */
2865 set_freepointer(s
, object
, df
->freelist
);
2866 df
->freelist
= object
;
2868 p
[size
] = NULL
; /* mark object processed */
2873 /* Limit look ahead search */
2877 if (!first_skipped_index
)
2878 first_skipped_index
= size
+ 1;
2881 return first_skipped_index
;
2885 /* Note that interrupts must be enabled when calling this function. */
2886 void kmem_cache_free_bulk(struct kmem_cache
*orig_s
, size_t size
, void **p
)
2892 struct detached_freelist df
;
2893 struct kmem_cache
*s
;
2895 /* Support for memcg */
2896 s
= cache_from_obj(orig_s
, p
[size
- 1]);
2898 size
= build_detached_freelist(s
, size
, p
, &df
);
2899 if (unlikely(!df
.page
))
2902 slab_free(s
, df
.page
, df
.freelist
, df
.tail
, df
.cnt
, _RET_IP_
);
2903 } while (likely(size
));
2905 EXPORT_SYMBOL(kmem_cache_free_bulk
);
2907 /* Note that interrupts must be enabled when calling this function. */
2908 int kmem_cache_alloc_bulk(struct kmem_cache
*s
, gfp_t flags
, size_t size
,
2911 struct kmem_cache_cpu
*c
;
2914 /* memcg and kmem_cache debug support */
2915 s
= slab_pre_alloc_hook(s
, flags
);
2919 * Drain objects in the per cpu slab, while disabling local
2920 * IRQs, which protects against PREEMPT and interrupts
2921 * handlers invoking normal fastpath.
2923 local_irq_disable();
2924 c
= this_cpu_ptr(s
->cpu_slab
);
2926 for (i
= 0; i
< size
; i
++) {
2927 void *object
= c
->freelist
;
2929 if (unlikely(!object
)) {
2931 * Invoking slow path likely have side-effect
2932 * of re-populating per CPU c->freelist
2934 p
[i
] = ___slab_alloc(s
, flags
, NUMA_NO_NODE
,
2936 if (unlikely(!p
[i
]))
2939 c
= this_cpu_ptr(s
->cpu_slab
);
2940 continue; /* goto for-loop */
2942 c
->freelist
= get_freepointer(s
, object
);
2945 c
->tid
= next_tid(c
->tid
);
2948 /* Clear memory outside IRQ disabled fastpath loop */
2949 if (unlikely(flags
& __GFP_ZERO
)) {
2952 for (j
= 0; j
< i
; j
++)
2953 memset(p
[j
], 0, s
->object_size
);
2956 /* memcg and kmem_cache debug support */
2957 slab_post_alloc_hook(s
, flags
, size
, p
);
2961 slab_post_alloc_hook(s
, flags
, i
, p
);
2962 __kmem_cache_free_bulk(s
, i
, p
);
2965 EXPORT_SYMBOL(kmem_cache_alloc_bulk
);
2969 * Object placement in a slab is made very easy because we always start at
2970 * offset 0. If we tune the size of the object to the alignment then we can
2971 * get the required alignment by putting one properly sized object after
2974 * Notice that the allocation order determines the sizes of the per cpu
2975 * caches. Each processor has always one slab available for allocations.
2976 * Increasing the allocation order reduces the number of times that slabs
2977 * must be moved on and off the partial lists and is therefore a factor in
2982 * Mininum / Maximum order of slab pages. This influences locking overhead
2983 * and slab fragmentation. A higher order reduces the number of partial slabs
2984 * and increases the number of allocations possible without having to
2985 * take the list_lock.
2987 static int slub_min_order
;
2988 static int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
2989 static int slub_min_objects
;
2992 * Calculate the order of allocation given an slab object size.
2994 * The order of allocation has significant impact on performance and other
2995 * system components. Generally order 0 allocations should be preferred since
2996 * order 0 does not cause fragmentation in the page allocator. Larger objects
2997 * be problematic to put into order 0 slabs because there may be too much
2998 * unused space left. We go to a higher order if more than 1/16th of the slab
3001 * In order to reach satisfactory performance we must ensure that a minimum
3002 * number of objects is in one slab. Otherwise we may generate too much
3003 * activity on the partial lists which requires taking the list_lock. This is
3004 * less a concern for large slabs though which are rarely used.
3006 * slub_max_order specifies the order where we begin to stop considering the
3007 * number of objects in a slab as critical. If we reach slub_max_order then
3008 * we try to keep the page order as low as possible. So we accept more waste
3009 * of space in favor of a small page order.
3011 * Higher order allocations also allow the placement of more objects in a
3012 * slab and thereby reduce object handling overhead. If the user has
3013 * requested a higher mininum order then we start with that one instead of
3014 * the smallest order which will fit the object.
3016 static inline int slab_order(int size
, int min_objects
,
3017 int max_order
, int fract_leftover
, int reserved
)
3021 int min_order
= slub_min_order
;
3023 if (order_objects(min_order
, size
, reserved
) > MAX_OBJS_PER_PAGE
)
3024 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
3026 for (order
= max(min_order
, get_order(min_objects
* size
+ reserved
));
3027 order
<= max_order
; order
++) {
3029 unsigned long slab_size
= PAGE_SIZE
<< order
;
3031 rem
= (slab_size
- reserved
) % size
;
3033 if (rem
<= slab_size
/ fract_leftover
)
3040 static inline int calculate_order(int size
, int reserved
)
3048 * Attempt to find best configuration for a slab. This
3049 * works by first attempting to generate a layout with
3050 * the best configuration and backing off gradually.
3052 * First we increase the acceptable waste in a slab. Then
3053 * we reduce the minimum objects required in a slab.
3055 min_objects
= slub_min_objects
;
3057 min_objects
= 4 * (fls(nr_cpu_ids
) + 1);
3058 max_objects
= order_objects(slub_max_order
, size
, reserved
);
3059 min_objects
= min(min_objects
, max_objects
);
3061 while (min_objects
> 1) {
3063 while (fraction
>= 4) {
3064 order
= slab_order(size
, min_objects
,
3065 slub_max_order
, fraction
, reserved
);
3066 if (order
<= slub_max_order
)
3074 * We were unable to place multiple objects in a slab. Now
3075 * lets see if we can place a single object there.
3077 order
= slab_order(size
, 1, slub_max_order
, 1, reserved
);
3078 if (order
<= slub_max_order
)
3082 * Doh this slab cannot be placed using slub_max_order.
3084 order
= slab_order(size
, 1, MAX_ORDER
, 1, reserved
);
3085 if (order
< MAX_ORDER
)
3091 init_kmem_cache_node(struct kmem_cache_node
*n
)
3094 spin_lock_init(&n
->list_lock
);
3095 INIT_LIST_HEAD(&n
->partial
);
3096 #ifdef CONFIG_SLUB_DEBUG
3097 atomic_long_set(&n
->nr_slabs
, 0);
3098 atomic_long_set(&n
->total_objects
, 0);
3099 INIT_LIST_HEAD(&n
->full
);
3103 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
3105 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
3106 KMALLOC_SHIFT_HIGH
* sizeof(struct kmem_cache_cpu
));
3109 * Must align to double word boundary for the double cmpxchg
3110 * instructions to work; see __pcpu_double_call_return_bool().
3112 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
3113 2 * sizeof(void *));
3118 init_kmem_cache_cpus(s
);
3123 static struct kmem_cache
*kmem_cache_node
;
3126 * No kmalloc_node yet so do it by hand. We know that this is the first
3127 * slab on the node for this slabcache. There are no concurrent accesses
3130 * Note that this function only works on the kmem_cache_node
3131 * when allocating for the kmem_cache_node. This is used for bootstrapping
3132 * memory on a fresh node that has no slab structures yet.
3134 static void early_kmem_cache_node_alloc(int node
)
3137 struct kmem_cache_node
*n
;
3139 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
3141 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
3144 if (page_to_nid(page
) != node
) {
3145 pr_err("SLUB: Unable to allocate memory from node %d\n", node
);
3146 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3151 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
3154 kmem_cache_node
->node
[node
] = n
;
3155 #ifdef CONFIG_SLUB_DEBUG
3156 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
3157 init_tracking(kmem_cache_node
, n
);
3159 kasan_kmalloc(kmem_cache_node
, n
, sizeof(struct kmem_cache_node
));
3160 init_kmem_cache_node(n
);
3161 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
3164 * No locks need to be taken here as it has just been
3165 * initialized and there is no concurrent access.
3167 __add_partial(n
, page
, DEACTIVATE_TO_HEAD
);
3170 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
3173 struct kmem_cache_node
*n
;
3175 for_each_kmem_cache_node(s
, node
, n
) {
3176 kmem_cache_free(kmem_cache_node
, n
);
3177 s
->node
[node
] = NULL
;
3181 void __kmem_cache_release(struct kmem_cache
*s
)
3183 free_percpu(s
->cpu_slab
);
3184 free_kmem_cache_nodes(s
);
3187 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
3191 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3192 struct kmem_cache_node
*n
;
3194 if (slab_state
== DOWN
) {
3195 early_kmem_cache_node_alloc(node
);
3198 n
= kmem_cache_alloc_node(kmem_cache_node
,
3202 free_kmem_cache_nodes(s
);
3207 init_kmem_cache_node(n
);
3212 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
3214 if (min
< MIN_PARTIAL
)
3216 else if (min
> MAX_PARTIAL
)
3218 s
->min_partial
= min
;
3222 * calculate_sizes() determines the order and the distribution of data within
3225 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
3227 unsigned long flags
= s
->flags
;
3228 unsigned long size
= s
->object_size
;
3232 * Round up object size to the next word boundary. We can only
3233 * place the free pointer at word boundaries and this determines
3234 * the possible location of the free pointer.
3236 size
= ALIGN(size
, sizeof(void *));
3238 #ifdef CONFIG_SLUB_DEBUG
3240 * Determine if we can poison the object itself. If the user of
3241 * the slab may touch the object after free or before allocation
3242 * then we should never poison the object itself.
3244 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
3246 s
->flags
|= __OBJECT_POISON
;
3248 s
->flags
&= ~__OBJECT_POISON
;
3252 * If we are Redzoning then check if there is some space between the
3253 * end of the object and the free pointer. If not then add an
3254 * additional word to have some bytes to store Redzone information.
3256 if ((flags
& SLAB_RED_ZONE
) && size
== s
->object_size
)
3257 size
+= sizeof(void *);
3261 * With that we have determined the number of bytes in actual use
3262 * by the object. This is the potential offset to the free pointer.
3266 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
3269 * Relocate free pointer after the object if it is not
3270 * permitted to overwrite the first word of the object on
3273 * This is the case if we do RCU, have a constructor or
3274 * destructor or are poisoning the objects.
3277 size
+= sizeof(void *);
3280 #ifdef CONFIG_SLUB_DEBUG
3281 if (flags
& SLAB_STORE_USER
)
3283 * Need to store information about allocs and frees after
3286 size
+= 2 * sizeof(struct track
);
3288 if (flags
& SLAB_RED_ZONE
)
3290 * Add some empty padding so that we can catch
3291 * overwrites from earlier objects rather than let
3292 * tracking information or the free pointer be
3293 * corrupted if a user writes before the start
3296 size
+= sizeof(void *);
3300 * SLUB stores one object immediately after another beginning from
3301 * offset 0. In order to align the objects we have to simply size
3302 * each object to conform to the alignment.
3304 size
= ALIGN(size
, s
->align
);
3306 if (forced_order
>= 0)
3307 order
= forced_order
;
3309 order
= calculate_order(size
, s
->reserved
);
3316 s
->allocflags
|= __GFP_COMP
;
3318 if (s
->flags
& SLAB_CACHE_DMA
)
3319 s
->allocflags
|= GFP_DMA
;
3321 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3322 s
->allocflags
|= __GFP_RECLAIMABLE
;
3325 * Determine the number of objects per slab
3327 s
->oo
= oo_make(order
, size
, s
->reserved
);
3328 s
->min
= oo_make(get_order(size
), size
, s
->reserved
);
3329 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
3332 return !!oo_objects(s
->oo
);
3335 static int kmem_cache_open(struct kmem_cache
*s
, unsigned long flags
)
3337 s
->flags
= kmem_cache_flags(s
->size
, flags
, s
->name
, s
->ctor
);
3340 if (need_reserve_slab_rcu
&& (s
->flags
& SLAB_DESTROY_BY_RCU
))
3341 s
->reserved
= sizeof(struct rcu_head
);
3343 if (!calculate_sizes(s
, -1))
3345 if (disable_higher_order_debug
) {
3347 * Disable debugging flags that store metadata if the min slab
3350 if (get_order(s
->size
) > get_order(s
->object_size
)) {
3351 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
3353 if (!calculate_sizes(s
, -1))
3358 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3359 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3360 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_DEBUG_FLAGS
) == 0)
3361 /* Enable fast mode */
3362 s
->flags
|= __CMPXCHG_DOUBLE
;
3366 * The larger the object size is, the more pages we want on the partial
3367 * list to avoid pounding the page allocator excessively.
3369 set_min_partial(s
, ilog2(s
->size
) / 2);
3372 * cpu_partial determined the maximum number of objects kept in the
3373 * per cpu partial lists of a processor.
3375 * Per cpu partial lists mainly contain slabs that just have one
3376 * object freed. If they are used for allocation then they can be
3377 * filled up again with minimal effort. The slab will never hit the
3378 * per node partial lists and therefore no locking will be required.
3380 * This setting also determines
3382 * A) The number of objects from per cpu partial slabs dumped to the
3383 * per node list when we reach the limit.
3384 * B) The number of objects in cpu partial slabs to extract from the
3385 * per node list when we run out of per cpu objects. We only fetch
3386 * 50% to keep some capacity around for frees.
3388 if (!kmem_cache_has_cpu_partial(s
))
3390 else if (s
->size
>= PAGE_SIZE
)
3392 else if (s
->size
>= 1024)
3394 else if (s
->size
>= 256)
3395 s
->cpu_partial
= 13;
3397 s
->cpu_partial
= 30;
3400 s
->remote_node_defrag_ratio
= 1000;
3402 if (!init_kmem_cache_nodes(s
))
3405 if (alloc_kmem_cache_cpus(s
))
3408 free_kmem_cache_nodes(s
);
3410 if (flags
& SLAB_PANIC
)
3411 panic("Cannot create slab %s size=%lu realsize=%u "
3412 "order=%u offset=%u flags=%lx\n",
3413 s
->name
, (unsigned long)s
->size
, s
->size
,
3414 oo_order(s
->oo
), s
->offset
, flags
);
3418 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
3421 #ifdef CONFIG_SLUB_DEBUG
3422 void *addr
= page_address(page
);
3424 unsigned long *map
= kzalloc(BITS_TO_LONGS(page
->objects
) *
3425 sizeof(long), GFP_ATOMIC
);
3428 slab_err(s
, page
, text
, s
->name
);
3431 get_map(s
, page
, map
);
3432 for_each_object(p
, s
, addr
, page
->objects
) {
3434 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
3435 pr_err("INFO: Object 0x%p @offset=%tu\n", p
, p
- addr
);
3436 print_tracking(s
, p
);
3445 * Attempt to free all partial slabs on a node.
3446 * This is called from __kmem_cache_shutdown(). We must take list_lock
3447 * because sysfs file might still access partial list after the shutdowning.
3449 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
3451 struct page
*page
, *h
;
3453 BUG_ON(irqs_disabled());
3454 spin_lock_irq(&n
->list_lock
);
3455 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
3457 remove_partial(n
, page
);
3458 discard_slab(s
, page
);
3460 list_slab_objects(s
, page
,
3461 "Objects remaining in %s on __kmem_cache_shutdown()");
3464 spin_unlock_irq(&n
->list_lock
);
3468 * Release all resources used by a slab cache.
3470 int __kmem_cache_shutdown(struct kmem_cache
*s
)
3473 struct kmem_cache_node
*n
;
3476 /* Attempt to free all objects */
3477 for_each_kmem_cache_node(s
, node
, n
) {
3479 if (n
->nr_partial
|| slabs_node(s
, node
))
3485 /********************************************************************
3487 *******************************************************************/
3489 static int __init
setup_slub_min_order(char *str
)
3491 get_option(&str
, &slub_min_order
);
3496 __setup("slub_min_order=", setup_slub_min_order
);
3498 static int __init
setup_slub_max_order(char *str
)
3500 get_option(&str
, &slub_max_order
);
3501 slub_max_order
= min(slub_max_order
, MAX_ORDER
- 1);
3506 __setup("slub_max_order=", setup_slub_max_order
);
3508 static int __init
setup_slub_min_objects(char *str
)
3510 get_option(&str
, &slub_min_objects
);
3515 __setup("slub_min_objects=", setup_slub_min_objects
);
3517 void *__kmalloc(size_t size
, gfp_t flags
)
3519 struct kmem_cache
*s
;
3522 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3523 return kmalloc_large(size
, flags
);
3525 s
= kmalloc_slab(size
, flags
);
3527 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3530 ret
= slab_alloc(s
, flags
, _RET_IP_
);
3532 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
3534 kasan_kmalloc(s
, ret
, size
);
3538 EXPORT_SYMBOL(__kmalloc
);
3541 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
3546 flags
|= __GFP_COMP
| __GFP_NOTRACK
;
3547 page
= alloc_kmem_pages_node(node
, flags
, get_order(size
));
3549 ptr
= page_address(page
);
3551 kmalloc_large_node_hook(ptr
, size
, flags
);
3555 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3557 struct kmem_cache
*s
;
3560 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3561 ret
= kmalloc_large_node(size
, flags
, node
);
3563 trace_kmalloc_node(_RET_IP_
, ret
,
3564 size
, PAGE_SIZE
<< get_order(size
),
3570 s
= kmalloc_slab(size
, flags
);
3572 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3575 ret
= slab_alloc_node(s
, flags
, node
, _RET_IP_
);
3577 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
3579 kasan_kmalloc(s
, ret
, size
);
3583 EXPORT_SYMBOL(__kmalloc_node
);
3586 static size_t __ksize(const void *object
)
3590 if (unlikely(object
== ZERO_SIZE_PTR
))
3593 page
= virt_to_head_page(object
);
3595 if (unlikely(!PageSlab(page
))) {
3596 WARN_ON(!PageCompound(page
));
3597 return PAGE_SIZE
<< compound_order(page
);
3600 return slab_ksize(page
->slab_cache
);
3603 size_t ksize(const void *object
)
3605 size_t size
= __ksize(object
);
3606 /* We assume that ksize callers could use whole allocated area,
3607 so we need unpoison this area. */
3608 kasan_krealloc(object
, size
);
3611 EXPORT_SYMBOL(ksize
);
3613 void kfree(const void *x
)
3616 void *object
= (void *)x
;
3618 trace_kfree(_RET_IP_
, x
);
3620 if (unlikely(ZERO_OR_NULL_PTR(x
)))
3623 page
= virt_to_head_page(x
);
3624 if (unlikely(!PageSlab(page
))) {
3625 BUG_ON(!PageCompound(page
));
3627 __free_kmem_pages(page
, compound_order(page
));
3630 slab_free(page
->slab_cache
, page
, object
, NULL
, 1, _RET_IP_
);
3632 EXPORT_SYMBOL(kfree
);
3634 #define SHRINK_PROMOTE_MAX 32
3637 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3638 * up most to the head of the partial lists. New allocations will then
3639 * fill those up and thus they can be removed from the partial lists.
3641 * The slabs with the least items are placed last. This results in them
3642 * being allocated from last increasing the chance that the last objects
3643 * are freed in them.
3645 int __kmem_cache_shrink(struct kmem_cache
*s
, bool deactivate
)
3649 struct kmem_cache_node
*n
;
3652 struct list_head discard
;
3653 struct list_head promote
[SHRINK_PROMOTE_MAX
];
3654 unsigned long flags
;
3659 * Disable empty slabs caching. Used to avoid pinning offline
3660 * memory cgroups by kmem pages that can be freed.
3666 * s->cpu_partial is checked locklessly (see put_cpu_partial),
3667 * so we have to make sure the change is visible.
3669 kick_all_cpus_sync();
3673 for_each_kmem_cache_node(s
, node
, n
) {
3674 INIT_LIST_HEAD(&discard
);
3675 for (i
= 0; i
< SHRINK_PROMOTE_MAX
; i
++)
3676 INIT_LIST_HEAD(promote
+ i
);
3678 spin_lock_irqsave(&n
->list_lock
, flags
);
3681 * Build lists of slabs to discard or promote.
3683 * Note that concurrent frees may occur while we hold the
3684 * list_lock. page->inuse here is the upper limit.
3686 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
3687 int free
= page
->objects
- page
->inuse
;
3689 /* Do not reread page->inuse */
3692 /* We do not keep full slabs on the list */
3695 if (free
== page
->objects
) {
3696 list_move(&page
->lru
, &discard
);
3698 } else if (free
<= SHRINK_PROMOTE_MAX
)
3699 list_move(&page
->lru
, promote
+ free
- 1);
3703 * Promote the slabs filled up most to the head of the
3706 for (i
= SHRINK_PROMOTE_MAX
- 1; i
>= 0; i
--)
3707 list_splice(promote
+ i
, &n
->partial
);
3709 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3711 /* Release empty slabs */
3712 list_for_each_entry_safe(page
, t
, &discard
, lru
)
3713 discard_slab(s
, page
);
3715 if (slabs_node(s
, node
))
3722 static int slab_mem_going_offline_callback(void *arg
)
3724 struct kmem_cache
*s
;
3726 mutex_lock(&slab_mutex
);
3727 list_for_each_entry(s
, &slab_caches
, list
)
3728 __kmem_cache_shrink(s
, false);
3729 mutex_unlock(&slab_mutex
);
3734 static void slab_mem_offline_callback(void *arg
)
3736 struct kmem_cache_node
*n
;
3737 struct kmem_cache
*s
;
3738 struct memory_notify
*marg
= arg
;
3741 offline_node
= marg
->status_change_nid_normal
;
3744 * If the node still has available memory. we need kmem_cache_node
3747 if (offline_node
< 0)
3750 mutex_lock(&slab_mutex
);
3751 list_for_each_entry(s
, &slab_caches
, list
) {
3752 n
= get_node(s
, offline_node
);
3755 * if n->nr_slabs > 0, slabs still exist on the node
3756 * that is going down. We were unable to free them,
3757 * and offline_pages() function shouldn't call this
3758 * callback. So, we must fail.
3760 BUG_ON(slabs_node(s
, offline_node
));
3762 s
->node
[offline_node
] = NULL
;
3763 kmem_cache_free(kmem_cache_node
, n
);
3766 mutex_unlock(&slab_mutex
);
3769 static int slab_mem_going_online_callback(void *arg
)
3771 struct kmem_cache_node
*n
;
3772 struct kmem_cache
*s
;
3773 struct memory_notify
*marg
= arg
;
3774 int nid
= marg
->status_change_nid_normal
;
3778 * If the node's memory is already available, then kmem_cache_node is
3779 * already created. Nothing to do.
3785 * We are bringing a node online. No memory is available yet. We must
3786 * allocate a kmem_cache_node structure in order to bring the node
3789 mutex_lock(&slab_mutex
);
3790 list_for_each_entry(s
, &slab_caches
, list
) {
3792 * XXX: kmem_cache_alloc_node will fallback to other nodes
3793 * since memory is not yet available from the node that
3796 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
3801 init_kmem_cache_node(n
);
3805 mutex_unlock(&slab_mutex
);
3809 static int slab_memory_callback(struct notifier_block
*self
,
3810 unsigned long action
, void *arg
)
3815 case MEM_GOING_ONLINE
:
3816 ret
= slab_mem_going_online_callback(arg
);
3818 case MEM_GOING_OFFLINE
:
3819 ret
= slab_mem_going_offline_callback(arg
);
3822 case MEM_CANCEL_ONLINE
:
3823 slab_mem_offline_callback(arg
);
3826 case MEM_CANCEL_OFFLINE
:
3830 ret
= notifier_from_errno(ret
);
3836 static struct notifier_block slab_memory_callback_nb
= {
3837 .notifier_call
= slab_memory_callback
,
3838 .priority
= SLAB_CALLBACK_PRI
,
3841 /********************************************************************
3842 * Basic setup of slabs
3843 *******************************************************************/
3846 * Used for early kmem_cache structures that were allocated using
3847 * the page allocator. Allocate them properly then fix up the pointers
3848 * that may be pointing to the wrong kmem_cache structure.
3851 static struct kmem_cache
* __init
bootstrap(struct kmem_cache
*static_cache
)
3854 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
3855 struct kmem_cache_node
*n
;
3857 memcpy(s
, static_cache
, kmem_cache
->object_size
);
3860 * This runs very early, and only the boot processor is supposed to be
3861 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3864 __flush_cpu_slab(s
, smp_processor_id());
3865 for_each_kmem_cache_node(s
, node
, n
) {
3868 list_for_each_entry(p
, &n
->partial
, lru
)
3871 #ifdef CONFIG_SLUB_DEBUG
3872 list_for_each_entry(p
, &n
->full
, lru
)
3876 slab_init_memcg_params(s
);
3877 list_add(&s
->list
, &slab_caches
);
3881 void __init
kmem_cache_init(void)
3883 static __initdata
struct kmem_cache boot_kmem_cache
,
3884 boot_kmem_cache_node
;
3886 if (debug_guardpage_minorder())
3889 kmem_cache_node
= &boot_kmem_cache_node
;
3890 kmem_cache
= &boot_kmem_cache
;
3892 create_boot_cache(kmem_cache_node
, "kmem_cache_node",
3893 sizeof(struct kmem_cache_node
), SLAB_HWCACHE_ALIGN
);
3895 register_hotmemory_notifier(&slab_memory_callback_nb
);
3897 /* Able to allocate the per node structures */
3898 slab_state
= PARTIAL
;
3900 create_boot_cache(kmem_cache
, "kmem_cache",
3901 offsetof(struct kmem_cache
, node
) +
3902 nr_node_ids
* sizeof(struct kmem_cache_node
*),
3903 SLAB_HWCACHE_ALIGN
);
3905 kmem_cache
= bootstrap(&boot_kmem_cache
);
3908 * Allocate kmem_cache_node properly from the kmem_cache slab.
3909 * kmem_cache_node is separately allocated so no need to
3910 * update any list pointers.
3912 kmem_cache_node
= bootstrap(&boot_kmem_cache_node
);
3914 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3915 setup_kmalloc_cache_index_table();
3916 create_kmalloc_caches(0);
3919 register_cpu_notifier(&slab_notifier
);
3922 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
3924 slub_min_order
, slub_max_order
, slub_min_objects
,
3925 nr_cpu_ids
, nr_node_ids
);
3928 void __init
kmem_cache_init_late(void)
3933 __kmem_cache_alias(const char *name
, size_t size
, size_t align
,
3934 unsigned long flags
, void (*ctor
)(void *))
3936 struct kmem_cache
*s
, *c
;
3938 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3943 * Adjust the object sizes so that we clear
3944 * the complete object on kzalloc.
3946 s
->object_size
= max(s
->object_size
, (int)size
);
3947 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3949 for_each_memcg_cache(c
, s
) {
3950 c
->object_size
= s
->object_size
;
3951 c
->inuse
= max_t(int, c
->inuse
,
3952 ALIGN(size
, sizeof(void *)));
3955 if (sysfs_slab_alias(s
, name
)) {
3964 int __kmem_cache_create(struct kmem_cache
*s
, unsigned long flags
)
3968 err
= kmem_cache_open(s
, flags
);
3972 /* Mutex is not taken during early boot */
3973 if (slab_state
<= UP
)
3976 memcg_propagate_slab_attrs(s
);
3977 err
= sysfs_slab_add(s
);
3979 __kmem_cache_release(s
);
3986 * Use the cpu notifier to insure that the cpu slabs are flushed when
3989 static int slab_cpuup_callback(struct notifier_block
*nfb
,
3990 unsigned long action
, void *hcpu
)
3992 long cpu
= (long)hcpu
;
3993 struct kmem_cache
*s
;
3994 unsigned long flags
;
3997 case CPU_UP_CANCELED
:
3998 case CPU_UP_CANCELED_FROZEN
:
4000 case CPU_DEAD_FROZEN
:
4001 mutex_lock(&slab_mutex
);
4002 list_for_each_entry(s
, &slab_caches
, list
) {
4003 local_irq_save(flags
);
4004 __flush_cpu_slab(s
, cpu
);
4005 local_irq_restore(flags
);
4007 mutex_unlock(&slab_mutex
);
4015 static struct notifier_block slab_notifier
= {
4016 .notifier_call
= slab_cpuup_callback
4021 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
4023 struct kmem_cache
*s
;
4026 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
4027 return kmalloc_large(size
, gfpflags
);
4029 s
= kmalloc_slab(size
, gfpflags
);
4031 if (unlikely(ZERO_OR_NULL_PTR(s
)))
4034 ret
= slab_alloc(s
, gfpflags
, caller
);
4036 /* Honor the call site pointer we received. */
4037 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
4043 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
4044 int node
, unsigned long caller
)
4046 struct kmem_cache
*s
;
4049 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
4050 ret
= kmalloc_large_node(size
, gfpflags
, node
);
4052 trace_kmalloc_node(caller
, ret
,
4053 size
, PAGE_SIZE
<< get_order(size
),
4059 s
= kmalloc_slab(size
, gfpflags
);
4061 if (unlikely(ZERO_OR_NULL_PTR(s
)))
4064 ret
= slab_alloc_node(s
, gfpflags
, node
, caller
);
4066 /* Honor the call site pointer we received. */
4067 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
4074 static int count_inuse(struct page
*page
)
4079 static int count_total(struct page
*page
)
4081 return page
->objects
;
4085 #ifdef CONFIG_SLUB_DEBUG
4086 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
4090 void *addr
= page_address(page
);
4092 if (!check_slab(s
, page
) ||
4093 !on_freelist(s
, page
, NULL
))
4096 /* Now we know that a valid freelist exists */
4097 bitmap_zero(map
, page
->objects
);
4099 get_map(s
, page
, map
);
4100 for_each_object(p
, s
, addr
, page
->objects
) {
4101 if (test_bit(slab_index(p
, s
, addr
), map
))
4102 if (!check_object(s
, page
, p
, SLUB_RED_INACTIVE
))
4106 for_each_object(p
, s
, addr
, page
->objects
)
4107 if (!test_bit(slab_index(p
, s
, addr
), map
))
4108 if (!check_object(s
, page
, p
, SLUB_RED_ACTIVE
))
4113 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
4117 validate_slab(s
, page
, map
);
4121 static int validate_slab_node(struct kmem_cache
*s
,
4122 struct kmem_cache_node
*n
, unsigned long *map
)
4124 unsigned long count
= 0;
4126 unsigned long flags
;
4128 spin_lock_irqsave(&n
->list_lock
, flags
);
4130 list_for_each_entry(page
, &n
->partial
, lru
) {
4131 validate_slab_slab(s
, page
, map
);
4134 if (count
!= n
->nr_partial
)
4135 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4136 s
->name
, count
, n
->nr_partial
);
4138 if (!(s
->flags
& SLAB_STORE_USER
))
4141 list_for_each_entry(page
, &n
->full
, lru
) {
4142 validate_slab_slab(s
, page
, map
);
4145 if (count
!= atomic_long_read(&n
->nr_slabs
))
4146 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4147 s
->name
, count
, atomic_long_read(&n
->nr_slabs
));
4150 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4154 static long validate_slab_cache(struct kmem_cache
*s
)
4157 unsigned long count
= 0;
4158 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4159 sizeof(unsigned long), GFP_KERNEL
);
4160 struct kmem_cache_node
*n
;
4166 for_each_kmem_cache_node(s
, node
, n
)
4167 count
+= validate_slab_node(s
, n
, map
);
4172 * Generate lists of code addresses where slabcache objects are allocated
4177 unsigned long count
;
4184 DECLARE_BITMAP(cpus
, NR_CPUS
);
4190 unsigned long count
;
4191 struct location
*loc
;
4194 static void free_loc_track(struct loc_track
*t
)
4197 free_pages((unsigned long)t
->loc
,
4198 get_order(sizeof(struct location
) * t
->max
));
4201 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
4206 order
= get_order(sizeof(struct location
) * max
);
4208 l
= (void *)__get_free_pages(flags
, order
);
4213 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
4221 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
4222 const struct track
*track
)
4224 long start
, end
, pos
;
4226 unsigned long caddr
;
4227 unsigned long age
= jiffies
- track
->when
;
4233 pos
= start
+ (end
- start
+ 1) / 2;
4236 * There is nothing at "end". If we end up there
4237 * we need to add something to before end.
4242 caddr
= t
->loc
[pos
].addr
;
4243 if (track
->addr
== caddr
) {
4249 if (age
< l
->min_time
)
4251 if (age
> l
->max_time
)
4254 if (track
->pid
< l
->min_pid
)
4255 l
->min_pid
= track
->pid
;
4256 if (track
->pid
> l
->max_pid
)
4257 l
->max_pid
= track
->pid
;
4259 cpumask_set_cpu(track
->cpu
,
4260 to_cpumask(l
->cpus
));
4262 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4266 if (track
->addr
< caddr
)
4273 * Not found. Insert new tracking element.
4275 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
4281 (t
->count
- pos
) * sizeof(struct location
));
4284 l
->addr
= track
->addr
;
4288 l
->min_pid
= track
->pid
;
4289 l
->max_pid
= track
->pid
;
4290 cpumask_clear(to_cpumask(l
->cpus
));
4291 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
4292 nodes_clear(l
->nodes
);
4293 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4297 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
4298 struct page
*page
, enum track_item alloc
,
4301 void *addr
= page_address(page
);
4304 bitmap_zero(map
, page
->objects
);
4305 get_map(s
, page
, map
);
4307 for_each_object(p
, s
, addr
, page
->objects
)
4308 if (!test_bit(slab_index(p
, s
, addr
), map
))
4309 add_location(t
, s
, get_track(s
, p
, alloc
));
4312 static int list_locations(struct kmem_cache
*s
, char *buf
,
4313 enum track_item alloc
)
4317 struct loc_track t
= { 0, 0, NULL
};
4319 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4320 sizeof(unsigned long), GFP_KERNEL
);
4321 struct kmem_cache_node
*n
;
4323 if (!map
|| !alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
4326 return sprintf(buf
, "Out of memory\n");
4328 /* Push back cpu slabs */
4331 for_each_kmem_cache_node(s
, node
, n
) {
4332 unsigned long flags
;
4335 if (!atomic_long_read(&n
->nr_slabs
))
4338 spin_lock_irqsave(&n
->list_lock
, flags
);
4339 list_for_each_entry(page
, &n
->partial
, lru
)
4340 process_slab(&t
, s
, page
, alloc
, map
);
4341 list_for_each_entry(page
, &n
->full
, lru
)
4342 process_slab(&t
, s
, page
, alloc
, map
);
4343 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4346 for (i
= 0; i
< t
.count
; i
++) {
4347 struct location
*l
= &t
.loc
[i
];
4349 if (len
> PAGE_SIZE
- KSYM_SYMBOL_LEN
- 100)
4351 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
4354 len
+= sprintf(buf
+ len
, "%pS", (void *)l
->addr
);
4356 len
+= sprintf(buf
+ len
, "<not-available>");
4358 if (l
->sum_time
!= l
->min_time
) {
4359 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
4361 (long)div_u64(l
->sum_time
, l
->count
),
4364 len
+= sprintf(buf
+ len
, " age=%ld",
4367 if (l
->min_pid
!= l
->max_pid
)
4368 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
4369 l
->min_pid
, l
->max_pid
);
4371 len
+= sprintf(buf
+ len
, " pid=%ld",
4374 if (num_online_cpus() > 1 &&
4375 !cpumask_empty(to_cpumask(l
->cpus
)) &&
4376 len
< PAGE_SIZE
- 60)
4377 len
+= scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4379 cpumask_pr_args(to_cpumask(l
->cpus
)));
4381 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
) &&
4382 len
< PAGE_SIZE
- 60)
4383 len
+= scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4385 nodemask_pr_args(&l
->nodes
));
4387 len
+= sprintf(buf
+ len
, "\n");
4393 len
+= sprintf(buf
, "No data\n");
4398 #ifdef SLUB_RESILIENCY_TEST
4399 static void __init
resiliency_test(void)
4403 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 16 || KMALLOC_SHIFT_HIGH
< 10);
4405 pr_err("SLUB resiliency testing\n");
4406 pr_err("-----------------------\n");
4407 pr_err("A. Corruption after allocation\n");
4409 p
= kzalloc(16, GFP_KERNEL
);
4411 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4414 validate_slab_cache(kmalloc_caches
[4]);
4416 /* Hmmm... The next two are dangerous */
4417 p
= kzalloc(32, GFP_KERNEL
);
4418 p
[32 + sizeof(void *)] = 0x34;
4419 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4421 pr_err("If allocated object is overwritten then not detectable\n\n");
4423 validate_slab_cache(kmalloc_caches
[5]);
4424 p
= kzalloc(64, GFP_KERNEL
);
4425 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
4427 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4429 pr_err("If allocated object is overwritten then not detectable\n\n");
4430 validate_slab_cache(kmalloc_caches
[6]);
4432 pr_err("\nB. Corruption after free\n");
4433 p
= kzalloc(128, GFP_KERNEL
);
4436 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
4437 validate_slab_cache(kmalloc_caches
[7]);
4439 p
= kzalloc(256, GFP_KERNEL
);
4442 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
4443 validate_slab_cache(kmalloc_caches
[8]);
4445 p
= kzalloc(512, GFP_KERNEL
);
4448 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
4449 validate_slab_cache(kmalloc_caches
[9]);
4453 static void resiliency_test(void) {};
4458 enum slab_stat_type
{
4459 SL_ALL
, /* All slabs */
4460 SL_PARTIAL
, /* Only partially allocated slabs */
4461 SL_CPU
, /* Only slabs used for cpu caches */
4462 SL_OBJECTS
, /* Determine allocated objects not slabs */
4463 SL_TOTAL
/* Determine object capacity not slabs */
4466 #define SO_ALL (1 << SL_ALL)
4467 #define SO_PARTIAL (1 << SL_PARTIAL)
4468 #define SO_CPU (1 << SL_CPU)
4469 #define SO_OBJECTS (1 << SL_OBJECTS)
4470 #define SO_TOTAL (1 << SL_TOTAL)
4472 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
4473 char *buf
, unsigned long flags
)
4475 unsigned long total
= 0;
4478 unsigned long *nodes
;
4480 nodes
= kzalloc(sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
4484 if (flags
& SO_CPU
) {
4487 for_each_possible_cpu(cpu
) {
4488 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
,
4493 page
= READ_ONCE(c
->page
);
4497 node
= page_to_nid(page
);
4498 if (flags
& SO_TOTAL
)
4500 else if (flags
& SO_OBJECTS
)
4508 page
= READ_ONCE(c
->partial
);
4510 node
= page_to_nid(page
);
4511 if (flags
& SO_TOTAL
)
4513 else if (flags
& SO_OBJECTS
)
4524 #ifdef CONFIG_SLUB_DEBUG
4525 if (flags
& SO_ALL
) {
4526 struct kmem_cache_node
*n
;
4528 for_each_kmem_cache_node(s
, node
, n
) {
4530 if (flags
& SO_TOTAL
)
4531 x
= atomic_long_read(&n
->total_objects
);
4532 else if (flags
& SO_OBJECTS
)
4533 x
= atomic_long_read(&n
->total_objects
) -
4534 count_partial(n
, count_free
);
4536 x
= atomic_long_read(&n
->nr_slabs
);
4543 if (flags
& SO_PARTIAL
) {
4544 struct kmem_cache_node
*n
;
4546 for_each_kmem_cache_node(s
, node
, n
) {
4547 if (flags
& SO_TOTAL
)
4548 x
= count_partial(n
, count_total
);
4549 else if (flags
& SO_OBJECTS
)
4550 x
= count_partial(n
, count_inuse
);
4557 x
= sprintf(buf
, "%lu", total
);
4559 for (node
= 0; node
< nr_node_ids
; node
++)
4561 x
+= sprintf(buf
+ x
, " N%d=%lu",
4566 return x
+ sprintf(buf
+ x
, "\n");
4569 #ifdef CONFIG_SLUB_DEBUG
4570 static int any_slab_objects(struct kmem_cache
*s
)
4573 struct kmem_cache_node
*n
;
4575 for_each_kmem_cache_node(s
, node
, n
)
4576 if (atomic_long_read(&n
->total_objects
))
4583 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4584 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4586 struct slab_attribute
{
4587 struct attribute attr
;
4588 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
4589 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
4592 #define SLAB_ATTR_RO(_name) \
4593 static struct slab_attribute _name##_attr = \
4594 __ATTR(_name, 0400, _name##_show, NULL)
4596 #define SLAB_ATTR(_name) \
4597 static struct slab_attribute _name##_attr = \
4598 __ATTR(_name, 0600, _name##_show, _name##_store)
4600 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
4602 return sprintf(buf
, "%d\n", s
->size
);
4604 SLAB_ATTR_RO(slab_size
);
4606 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
4608 return sprintf(buf
, "%d\n", s
->align
);
4610 SLAB_ATTR_RO(align
);
4612 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
4614 return sprintf(buf
, "%d\n", s
->object_size
);
4616 SLAB_ATTR_RO(object_size
);
4618 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
4620 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
4622 SLAB_ATTR_RO(objs_per_slab
);
4624 static ssize_t
order_store(struct kmem_cache
*s
,
4625 const char *buf
, size_t length
)
4627 unsigned long order
;
4630 err
= kstrtoul(buf
, 10, &order
);
4634 if (order
> slub_max_order
|| order
< slub_min_order
)
4637 calculate_sizes(s
, order
);
4641 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
4643 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
4647 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
4649 return sprintf(buf
, "%lu\n", s
->min_partial
);
4652 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
4658 err
= kstrtoul(buf
, 10, &min
);
4662 set_min_partial(s
, min
);
4665 SLAB_ATTR(min_partial
);
4667 static ssize_t
cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4669 return sprintf(buf
, "%u\n", s
->cpu_partial
);
4672 static ssize_t
cpu_partial_store(struct kmem_cache
*s
, const char *buf
,
4675 unsigned long objects
;
4678 err
= kstrtoul(buf
, 10, &objects
);
4681 if (objects
&& !kmem_cache_has_cpu_partial(s
))
4684 s
->cpu_partial
= objects
;
4688 SLAB_ATTR(cpu_partial
);
4690 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
4694 return sprintf(buf
, "%pS\n", s
->ctor
);
4698 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
4700 return sprintf(buf
, "%d\n", s
->refcount
< 0 ? 0 : s
->refcount
- 1);
4702 SLAB_ATTR_RO(aliases
);
4704 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
4706 return show_slab_objects(s
, buf
, SO_PARTIAL
);
4708 SLAB_ATTR_RO(partial
);
4710 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
4712 return show_slab_objects(s
, buf
, SO_CPU
);
4714 SLAB_ATTR_RO(cpu_slabs
);
4716 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
4718 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
4720 SLAB_ATTR_RO(objects
);
4722 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
4724 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
4726 SLAB_ATTR_RO(objects_partial
);
4728 static ssize_t
slabs_cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4735 for_each_online_cpu(cpu
) {
4736 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
)->partial
;
4739 pages
+= page
->pages
;
4740 objects
+= page
->pobjects
;
4744 len
= sprintf(buf
, "%d(%d)", objects
, pages
);
4747 for_each_online_cpu(cpu
) {
4748 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
) ->partial
;
4750 if (page
&& len
< PAGE_SIZE
- 20)
4751 len
+= sprintf(buf
+ len
, " C%d=%d(%d)", cpu
,
4752 page
->pobjects
, page
->pages
);
4755 return len
+ sprintf(buf
+ len
, "\n");
4757 SLAB_ATTR_RO(slabs_cpu_partial
);
4759 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
4761 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
4764 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
4765 const char *buf
, size_t length
)
4767 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
4769 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
4772 SLAB_ATTR(reclaim_account
);
4774 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
4776 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
4778 SLAB_ATTR_RO(hwcache_align
);
4780 #ifdef CONFIG_ZONE_DMA
4781 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
4783 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
4785 SLAB_ATTR_RO(cache_dma
);
4788 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
4790 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
4792 SLAB_ATTR_RO(destroy_by_rcu
);
4794 static ssize_t
reserved_show(struct kmem_cache
*s
, char *buf
)
4796 return sprintf(buf
, "%d\n", s
->reserved
);
4798 SLAB_ATTR_RO(reserved
);
4800 #ifdef CONFIG_SLUB_DEBUG
4801 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
4803 return show_slab_objects(s
, buf
, SO_ALL
);
4805 SLAB_ATTR_RO(slabs
);
4807 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
4809 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
4811 SLAB_ATTR_RO(total_objects
);
4813 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
4815 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
4818 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
4819 const char *buf
, size_t length
)
4821 s
->flags
&= ~SLAB_DEBUG_FREE
;
4822 if (buf
[0] == '1') {
4823 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4824 s
->flags
|= SLAB_DEBUG_FREE
;
4828 SLAB_ATTR(sanity_checks
);
4830 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
4832 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
4835 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
4839 * Tracing a merged cache is going to give confusing results
4840 * as well as cause other issues like converting a mergeable
4841 * cache into an umergeable one.
4843 if (s
->refcount
> 1)
4846 s
->flags
&= ~SLAB_TRACE
;
4847 if (buf
[0] == '1') {
4848 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4849 s
->flags
|= SLAB_TRACE
;
4855 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
4857 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
4860 static ssize_t
red_zone_store(struct kmem_cache
*s
,
4861 const char *buf
, size_t length
)
4863 if (any_slab_objects(s
))
4866 s
->flags
&= ~SLAB_RED_ZONE
;
4867 if (buf
[0] == '1') {
4868 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4869 s
->flags
|= SLAB_RED_ZONE
;
4871 calculate_sizes(s
, -1);
4874 SLAB_ATTR(red_zone
);
4876 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
4878 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
4881 static ssize_t
poison_store(struct kmem_cache
*s
,
4882 const char *buf
, size_t length
)
4884 if (any_slab_objects(s
))
4887 s
->flags
&= ~SLAB_POISON
;
4888 if (buf
[0] == '1') {
4889 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4890 s
->flags
|= SLAB_POISON
;
4892 calculate_sizes(s
, -1);
4897 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
4899 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
4902 static ssize_t
store_user_store(struct kmem_cache
*s
,
4903 const char *buf
, size_t length
)
4905 if (any_slab_objects(s
))
4908 s
->flags
&= ~SLAB_STORE_USER
;
4909 if (buf
[0] == '1') {
4910 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4911 s
->flags
|= SLAB_STORE_USER
;
4913 calculate_sizes(s
, -1);
4916 SLAB_ATTR(store_user
);
4918 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4923 static ssize_t
validate_store(struct kmem_cache
*s
,
4924 const char *buf
, size_t length
)
4928 if (buf
[0] == '1') {
4929 ret
= validate_slab_cache(s
);
4935 SLAB_ATTR(validate
);
4937 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4939 if (!(s
->flags
& SLAB_STORE_USER
))
4941 return list_locations(s
, buf
, TRACK_ALLOC
);
4943 SLAB_ATTR_RO(alloc_calls
);
4945 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4947 if (!(s
->flags
& SLAB_STORE_USER
))
4949 return list_locations(s
, buf
, TRACK_FREE
);
4951 SLAB_ATTR_RO(free_calls
);
4952 #endif /* CONFIG_SLUB_DEBUG */
4954 #ifdef CONFIG_FAILSLAB
4955 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
4957 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
4960 static ssize_t
failslab_store(struct kmem_cache
*s
, const char *buf
,
4963 if (s
->refcount
> 1)
4966 s
->flags
&= ~SLAB_FAILSLAB
;
4968 s
->flags
|= SLAB_FAILSLAB
;
4971 SLAB_ATTR(failslab
);
4974 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4979 static ssize_t
shrink_store(struct kmem_cache
*s
,
4980 const char *buf
, size_t length
)
4983 kmem_cache_shrink(s
);
4991 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4993 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4996 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4997 const char *buf
, size_t length
)
4999 unsigned long ratio
;
5002 err
= kstrtoul(buf
, 10, &ratio
);
5007 s
->remote_node_defrag_ratio
= ratio
* 10;
5011 SLAB_ATTR(remote_node_defrag_ratio
);
5014 #ifdef CONFIG_SLUB_STATS
5015 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
5017 unsigned long sum
= 0;
5020 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
5025 for_each_online_cpu(cpu
) {
5026 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
5032 len
= sprintf(buf
, "%lu", sum
);
5035 for_each_online_cpu(cpu
) {
5036 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
5037 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
5041 return len
+ sprintf(buf
+ len
, "\n");
5044 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
5048 for_each_online_cpu(cpu
)
5049 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
5052 #define STAT_ATTR(si, text) \
5053 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5055 return show_stat(s, buf, si); \
5057 static ssize_t text##_store(struct kmem_cache *s, \
5058 const char *buf, size_t length) \
5060 if (buf[0] != '0') \
5062 clear_stat(s, si); \
5067 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5068 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
5069 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
5070 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
5071 STAT_ATTR(FREE_FROZEN
, free_frozen
);
5072 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
5073 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
5074 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
5075 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
5076 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
5077 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
5078 STAT_ATTR(FREE_SLAB
, free_slab
);
5079 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
5080 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
5081 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
5082 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
5083 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
5084 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
5085 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
5086 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
5087 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
5088 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
5089 STAT_ATTR(CPU_PARTIAL_ALLOC
, cpu_partial_alloc
);
5090 STAT_ATTR(CPU_PARTIAL_FREE
, cpu_partial_free
);
5091 STAT_ATTR(CPU_PARTIAL_NODE
, cpu_partial_node
);
5092 STAT_ATTR(CPU_PARTIAL_DRAIN
, cpu_partial_drain
);
5095 static struct attribute
*slab_attrs
[] = {
5096 &slab_size_attr
.attr
,
5097 &object_size_attr
.attr
,
5098 &objs_per_slab_attr
.attr
,
5100 &min_partial_attr
.attr
,
5101 &cpu_partial_attr
.attr
,
5103 &objects_partial_attr
.attr
,
5105 &cpu_slabs_attr
.attr
,
5109 &hwcache_align_attr
.attr
,
5110 &reclaim_account_attr
.attr
,
5111 &destroy_by_rcu_attr
.attr
,
5113 &reserved_attr
.attr
,
5114 &slabs_cpu_partial_attr
.attr
,
5115 #ifdef CONFIG_SLUB_DEBUG
5116 &total_objects_attr
.attr
,
5118 &sanity_checks_attr
.attr
,
5120 &red_zone_attr
.attr
,
5122 &store_user_attr
.attr
,
5123 &validate_attr
.attr
,
5124 &alloc_calls_attr
.attr
,
5125 &free_calls_attr
.attr
,
5127 #ifdef CONFIG_ZONE_DMA
5128 &cache_dma_attr
.attr
,
5131 &remote_node_defrag_ratio_attr
.attr
,
5133 #ifdef CONFIG_SLUB_STATS
5134 &alloc_fastpath_attr
.attr
,
5135 &alloc_slowpath_attr
.attr
,
5136 &free_fastpath_attr
.attr
,
5137 &free_slowpath_attr
.attr
,
5138 &free_frozen_attr
.attr
,
5139 &free_add_partial_attr
.attr
,
5140 &free_remove_partial_attr
.attr
,
5141 &alloc_from_partial_attr
.attr
,
5142 &alloc_slab_attr
.attr
,
5143 &alloc_refill_attr
.attr
,
5144 &alloc_node_mismatch_attr
.attr
,
5145 &free_slab_attr
.attr
,
5146 &cpuslab_flush_attr
.attr
,
5147 &deactivate_full_attr
.attr
,
5148 &deactivate_empty_attr
.attr
,
5149 &deactivate_to_head_attr
.attr
,
5150 &deactivate_to_tail_attr
.attr
,
5151 &deactivate_remote_frees_attr
.attr
,
5152 &deactivate_bypass_attr
.attr
,
5153 &order_fallback_attr
.attr
,
5154 &cmpxchg_double_fail_attr
.attr
,
5155 &cmpxchg_double_cpu_fail_attr
.attr
,
5156 &cpu_partial_alloc_attr
.attr
,
5157 &cpu_partial_free_attr
.attr
,
5158 &cpu_partial_node_attr
.attr
,
5159 &cpu_partial_drain_attr
.attr
,
5161 #ifdef CONFIG_FAILSLAB
5162 &failslab_attr
.attr
,
5168 static struct attribute_group slab_attr_group
= {
5169 .attrs
= slab_attrs
,
5172 static ssize_t
slab_attr_show(struct kobject
*kobj
,
5173 struct attribute
*attr
,
5176 struct slab_attribute
*attribute
;
5177 struct kmem_cache
*s
;
5180 attribute
= to_slab_attr(attr
);
5183 if (!attribute
->show
)
5186 err
= attribute
->show(s
, buf
);
5191 static ssize_t
slab_attr_store(struct kobject
*kobj
,
5192 struct attribute
*attr
,
5193 const char *buf
, size_t len
)
5195 struct slab_attribute
*attribute
;
5196 struct kmem_cache
*s
;
5199 attribute
= to_slab_attr(attr
);
5202 if (!attribute
->store
)
5205 err
= attribute
->store(s
, buf
, len
);
5207 if (slab_state
>= FULL
&& err
>= 0 && is_root_cache(s
)) {
5208 struct kmem_cache
*c
;
5210 mutex_lock(&slab_mutex
);
5211 if (s
->max_attr_size
< len
)
5212 s
->max_attr_size
= len
;
5215 * This is a best effort propagation, so this function's return
5216 * value will be determined by the parent cache only. This is
5217 * basically because not all attributes will have a well
5218 * defined semantics for rollbacks - most of the actions will
5219 * have permanent effects.
5221 * Returning the error value of any of the children that fail
5222 * is not 100 % defined, in the sense that users seeing the
5223 * error code won't be able to know anything about the state of
5226 * Only returning the error code for the parent cache at least
5227 * has well defined semantics. The cache being written to
5228 * directly either failed or succeeded, in which case we loop
5229 * through the descendants with best-effort propagation.
5231 for_each_memcg_cache(c
, s
)
5232 attribute
->store(c
, buf
, len
);
5233 mutex_unlock(&slab_mutex
);
5239 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
)
5243 char *buffer
= NULL
;
5244 struct kmem_cache
*root_cache
;
5246 if (is_root_cache(s
))
5249 root_cache
= s
->memcg_params
.root_cache
;
5252 * This mean this cache had no attribute written. Therefore, no point
5253 * in copying default values around
5255 if (!root_cache
->max_attr_size
)
5258 for (i
= 0; i
< ARRAY_SIZE(slab_attrs
); i
++) {
5261 struct slab_attribute
*attr
= to_slab_attr(slab_attrs
[i
]);
5263 if (!attr
|| !attr
->store
|| !attr
->show
)
5267 * It is really bad that we have to allocate here, so we will
5268 * do it only as a fallback. If we actually allocate, though,
5269 * we can just use the allocated buffer until the end.
5271 * Most of the slub attributes will tend to be very small in
5272 * size, but sysfs allows buffers up to a page, so they can
5273 * theoretically happen.
5277 else if (root_cache
->max_attr_size
< ARRAY_SIZE(mbuf
))
5280 buffer
= (char *) get_zeroed_page(GFP_KERNEL
);
5281 if (WARN_ON(!buffer
))
5286 attr
->show(root_cache
, buf
);
5287 attr
->store(s
, buf
, strlen(buf
));
5291 free_page((unsigned long)buffer
);
5295 static void kmem_cache_release(struct kobject
*k
)
5297 slab_kmem_cache_release(to_slab(k
));
5300 static const struct sysfs_ops slab_sysfs_ops
= {
5301 .show
= slab_attr_show
,
5302 .store
= slab_attr_store
,
5305 static struct kobj_type slab_ktype
= {
5306 .sysfs_ops
= &slab_sysfs_ops
,
5307 .release
= kmem_cache_release
,
5310 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
5312 struct kobj_type
*ktype
= get_ktype(kobj
);
5314 if (ktype
== &slab_ktype
)
5319 static const struct kset_uevent_ops slab_uevent_ops
= {
5320 .filter
= uevent_filter
,
5323 static struct kset
*slab_kset
;
5325 static inline struct kset
*cache_kset(struct kmem_cache
*s
)
5328 if (!is_root_cache(s
))
5329 return s
->memcg_params
.root_cache
->memcg_kset
;
5334 #define ID_STR_LENGTH 64
5336 /* Create a unique string id for a slab cache:
5338 * Format :[flags-]size
5340 static char *create_unique_id(struct kmem_cache
*s
)
5342 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
5349 * First flags affecting slabcache operations. We will only
5350 * get here for aliasable slabs so we do not need to support
5351 * too many flags. The flags here must cover all flags that
5352 * are matched during merging to guarantee that the id is
5355 if (s
->flags
& SLAB_CACHE_DMA
)
5357 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
5359 if (s
->flags
& SLAB_DEBUG_FREE
)
5361 if (!(s
->flags
& SLAB_NOTRACK
))
5363 if (s
->flags
& SLAB_ACCOUNT
)
5367 p
+= sprintf(p
, "%07d", s
->size
);
5369 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
5373 static int sysfs_slab_add(struct kmem_cache
*s
)
5377 int unmergeable
= slab_unmergeable(s
);
5381 * Slabcache can never be merged so we can use the name proper.
5382 * This is typically the case for debug situations. In that
5383 * case we can catch duplicate names easily.
5385 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
5389 * Create a unique name for the slab as a target
5392 name
= create_unique_id(s
);
5395 s
->kobj
.kset
= cache_kset(s
);
5396 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, "%s", name
);
5400 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
5405 if (is_root_cache(s
)) {
5406 s
->memcg_kset
= kset_create_and_add("cgroup", NULL
, &s
->kobj
);
5407 if (!s
->memcg_kset
) {
5414 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
5416 /* Setup first alias */
5417 sysfs_slab_alias(s
, s
->name
);
5424 kobject_del(&s
->kobj
);
5428 void sysfs_slab_remove(struct kmem_cache
*s
)
5430 if (slab_state
< FULL
)
5432 * Sysfs has not been setup yet so no need to remove the
5438 kset_unregister(s
->memcg_kset
);
5440 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
5441 kobject_del(&s
->kobj
);
5442 kobject_put(&s
->kobj
);
5446 * Need to buffer aliases during bootup until sysfs becomes
5447 * available lest we lose that information.
5449 struct saved_alias
{
5450 struct kmem_cache
*s
;
5452 struct saved_alias
*next
;
5455 static struct saved_alias
*alias_list
;
5457 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5459 struct saved_alias
*al
;
5461 if (slab_state
== FULL
) {
5463 * If we have a leftover link then remove it.
5465 sysfs_remove_link(&slab_kset
->kobj
, name
);
5466 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5469 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5475 al
->next
= alias_list
;
5480 static int __init
slab_sysfs_init(void)
5482 struct kmem_cache
*s
;
5485 mutex_lock(&slab_mutex
);
5487 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
5489 mutex_unlock(&slab_mutex
);
5490 pr_err("Cannot register slab subsystem.\n");
5496 list_for_each_entry(s
, &slab_caches
, list
) {
5497 err
= sysfs_slab_add(s
);
5499 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5503 while (alias_list
) {
5504 struct saved_alias
*al
= alias_list
;
5506 alias_list
= alias_list
->next
;
5507 err
= sysfs_slab_alias(al
->s
, al
->name
);
5509 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5514 mutex_unlock(&slab_mutex
);
5519 __initcall(slab_sysfs_init
);
5520 #endif /* CONFIG_SYSFS */
5523 * The /proc/slabinfo ABI
5525 #ifdef CONFIG_SLABINFO
5526 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
)
5528 unsigned long nr_slabs
= 0;
5529 unsigned long nr_objs
= 0;
5530 unsigned long nr_free
= 0;
5532 struct kmem_cache_node
*n
;
5534 for_each_kmem_cache_node(s
, node
, n
) {
5535 nr_slabs
+= node_nr_slabs(n
);
5536 nr_objs
+= node_nr_objs(n
);
5537 nr_free
+= count_partial(n
, count_free
);
5540 sinfo
->active_objs
= nr_objs
- nr_free
;
5541 sinfo
->num_objs
= nr_objs
;
5542 sinfo
->active_slabs
= nr_slabs
;
5543 sinfo
->num_slabs
= nr_slabs
;
5544 sinfo
->objects_per_slab
= oo_objects(s
->oo
);
5545 sinfo
->cache_order
= oo_order(s
->oo
);
5548 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
)
5552 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
5553 size_t count
, loff_t
*ppos
)
5557 #endif /* CONFIG_SLABINFO */