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/kmemcheck.h>
24 #include <linux/cpu.h>
25 #include <linux/cpuset.h>
26 #include <linux/mempolicy.h>
27 #include <linux/ctype.h>
28 #include <linux/debugobjects.h>
29 #include <linux/kallsyms.h>
30 #include <linux/memory.h>
31 #include <linux/math64.h>
32 #include <linux/fault-inject.h>
33 #include <linux/stacktrace.h>
34 #include <linux/prefetch.h>
35 #include <linux/memcontrol.h>
37 #include <trace/events/kmem.h>
43 * 1. slab_mutex (Global Mutex)
45 * 3. slab_lock(page) (Only on some arches and for debugging)
49 * The role of the slab_mutex is to protect the list of all the slabs
50 * and to synchronize major metadata changes to slab cache structures.
52 * The slab_lock is only used for debugging and on arches that do not
53 * have the ability to do a cmpxchg_double. It only protects the second
54 * double word in the page struct. Meaning
55 * A. page->freelist -> List of object free in a page
56 * B. page->counters -> Counters of objects
57 * C. page->frozen -> frozen state
59 * If a slab is frozen then it is exempt from list management. It is not
60 * on any list. The processor that froze the slab is the one who can
61 * perform list operations on the page. Other processors may put objects
62 * onto the freelist but the processor that froze the slab is the only
63 * one that can retrieve the objects from the page's freelist.
65 * The list_lock protects the partial and full list on each node and
66 * the partial slab counter. If taken then no new slabs may be added or
67 * removed from the lists nor make the number of partial slabs be modified.
68 * (Note that the total number of slabs is an atomic value that may be
69 * modified without taking the list lock).
71 * The list_lock is a centralized lock and thus we avoid taking it as
72 * much as possible. As long as SLUB does not have to handle partial
73 * slabs, operations can continue without any centralized lock. F.e.
74 * allocating a long series of objects that fill up slabs does not require
76 * Interrupts are disabled during allocation and deallocation in order to
77 * make the slab allocator safe to use in the context of an irq. In addition
78 * interrupts are disabled to ensure that the processor does not change
79 * while handling per_cpu slabs, due to kernel preemption.
81 * SLUB assigns one slab for allocation to each processor.
82 * Allocations only occur from these slabs called cpu slabs.
84 * Slabs with free elements are kept on a partial list and during regular
85 * operations no list for full slabs is used. If an object in a full slab is
86 * freed then the slab will show up again on the partial lists.
87 * We track full slabs for debugging purposes though because otherwise we
88 * cannot scan all objects.
90 * Slabs are freed when they become empty. Teardown and setup is
91 * minimal so we rely on the page allocators per cpu caches for
92 * fast frees and allocs.
94 * Overloading of page flags that are otherwise used for LRU management.
96 * PageActive The slab is frozen and exempt from list processing.
97 * This means that the slab is dedicated to a purpose
98 * such as satisfying allocations for a specific
99 * processor. Objects may be freed in the slab while
100 * it is frozen but slab_free will then skip the usual
101 * list operations. It is up to the processor holding
102 * the slab to integrate the slab into the slab lists
103 * when the slab is no longer needed.
105 * One use of this flag is to mark slabs that are
106 * used for allocations. Then such a slab becomes a cpu
107 * slab. The cpu slab may be equipped with an additional
108 * freelist that allows lockless access to
109 * free objects in addition to the regular freelist
110 * that requires the slab lock.
112 * PageError Slab requires special handling due to debug
113 * options set. This moves slab handling out of
114 * the fast path and disables lockless freelists.
117 static inline int kmem_cache_debug(struct kmem_cache
*s
)
119 #ifdef CONFIG_SLUB_DEBUG
120 return unlikely(s
->flags
& SLAB_DEBUG_FLAGS
);
126 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache
*s
)
128 #ifdef CONFIG_SLUB_CPU_PARTIAL
129 return !kmem_cache_debug(s
);
136 * Issues still to be resolved:
138 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
140 * - Variable sizing of the per node arrays
143 /* Enable to test recovery from slab corruption on boot */
144 #undef SLUB_RESILIENCY_TEST
146 /* Enable to log cmpxchg failures */
147 #undef SLUB_DEBUG_CMPXCHG
150 * Mininum number of partial slabs. These will be left on the partial
151 * lists even if they are empty. kmem_cache_shrink may reclaim them.
153 #define MIN_PARTIAL 5
156 * Maximum number of desirable partial slabs.
157 * The existence of more partial slabs makes kmem_cache_shrink
158 * sort the partial list by the number of objects in use.
160 #define MAX_PARTIAL 10
162 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
163 SLAB_POISON | SLAB_STORE_USER)
166 * Debugging flags that require metadata to be stored in the slab. These get
167 * disabled when slub_debug=O is used and a cache's min order increases with
170 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
173 #define OO_MASK ((1 << OO_SHIFT) - 1)
174 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
176 /* Internal SLUB flags */
177 #define __OBJECT_POISON 0x80000000UL /* Poison object */
178 #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
181 static struct notifier_block slab_notifier
;
185 * Tracking user of a slab.
187 #define TRACK_ADDRS_COUNT 16
189 unsigned long addr
; /* Called from address */
190 #ifdef CONFIG_STACKTRACE
191 unsigned long addrs
[TRACK_ADDRS_COUNT
]; /* Called from address */
193 int cpu
; /* Was running on cpu */
194 int pid
; /* Pid context */
195 unsigned long when
; /* When did the operation occur */
198 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
201 static int sysfs_slab_add(struct kmem_cache
*);
202 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
203 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
);
205 static inline int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
206 static inline int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
)
208 static inline void memcg_propagate_slab_attrs(struct kmem_cache
*s
) { }
211 static inline void stat(const struct kmem_cache
*s
, enum stat_item si
)
213 #ifdef CONFIG_SLUB_STATS
215 * The rmw is racy on a preemptible kernel but this is acceptable, so
216 * avoid this_cpu_add()'s irq-disable overhead.
218 raw_cpu_inc(s
->cpu_slab
->stat
[si
]);
222 /********************************************************************
223 * Core slab cache functions
224 *******************************************************************/
226 /* Verify that a pointer has an address that is valid within a slab page */
227 static inline int check_valid_pointer(struct kmem_cache
*s
,
228 struct page
*page
, const void *object
)
235 base
= page_address(page
);
236 if (object
< base
|| object
>= base
+ page
->objects
* s
->size
||
237 (object
- base
) % s
->size
) {
244 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
246 return *(void **)(object
+ s
->offset
);
249 static void prefetch_freepointer(const struct kmem_cache
*s
, void *object
)
251 prefetch(object
+ s
->offset
);
254 static inline void *get_freepointer_safe(struct kmem_cache
*s
, void *object
)
258 #ifdef CONFIG_DEBUG_PAGEALLOC
259 probe_kernel_read(&p
, (void **)(object
+ s
->offset
), sizeof(p
));
261 p
= get_freepointer(s
, object
);
266 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
268 *(void **)(object
+ s
->offset
) = fp
;
271 /* Loop over all objects in a slab */
272 #define for_each_object(__p, __s, __addr, __objects) \
273 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
276 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
277 for (__p = (__addr), __idx = 1; __idx <= __objects;\
278 __p += (__s)->size, __idx++)
280 /* Determine object index from a given position */
281 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
283 return (p
- addr
) / s
->size
;
286 static inline size_t slab_ksize(const struct kmem_cache
*s
)
288 #ifdef CONFIG_SLUB_DEBUG
290 * Debugging requires use of the padding between object
291 * and whatever may come after it.
293 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
294 return s
->object_size
;
298 * If we have the need to store the freelist pointer
299 * back there or track user information then we can
300 * only use the space before that information.
302 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
305 * Else we can use all the padding etc for the allocation
310 static inline int order_objects(int order
, unsigned long size
, int reserved
)
312 return ((PAGE_SIZE
<< order
) - reserved
) / size
;
315 static inline struct kmem_cache_order_objects
oo_make(int order
,
316 unsigned long size
, int reserved
)
318 struct kmem_cache_order_objects x
= {
319 (order
<< OO_SHIFT
) + order_objects(order
, size
, reserved
)
325 static inline int oo_order(struct kmem_cache_order_objects x
)
327 return x
.x
>> OO_SHIFT
;
330 static inline int oo_objects(struct kmem_cache_order_objects x
)
332 return x
.x
& OO_MASK
;
336 * Per slab locking using the pagelock
338 static __always_inline
void slab_lock(struct page
*page
)
340 bit_spin_lock(PG_locked
, &page
->flags
);
343 static __always_inline
void slab_unlock(struct page
*page
)
345 __bit_spin_unlock(PG_locked
, &page
->flags
);
348 static inline void set_page_slub_counters(struct page
*page
, unsigned long counters_new
)
351 tmp
.counters
= counters_new
;
353 * page->counters can cover frozen/inuse/objects as well
354 * as page->_count. If we assign to ->counters directly
355 * we run the risk of losing updates to page->_count, so
356 * be careful and only assign to the fields we need.
358 page
->frozen
= tmp
.frozen
;
359 page
->inuse
= tmp
.inuse
;
360 page
->objects
= tmp
.objects
;
363 /* Interrupts must be disabled (for the fallback code to work right) */
364 static inline bool __cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
365 void *freelist_old
, unsigned long counters_old
,
366 void *freelist_new
, unsigned long counters_new
,
369 VM_BUG_ON(!irqs_disabled());
370 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
371 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
372 if (s
->flags
& __CMPXCHG_DOUBLE
) {
373 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
374 freelist_old
, counters_old
,
375 freelist_new
, counters_new
))
381 if (page
->freelist
== freelist_old
&&
382 page
->counters
== counters_old
) {
383 page
->freelist
= freelist_new
;
384 set_page_slub_counters(page
, counters_new
);
392 stat(s
, CMPXCHG_DOUBLE_FAIL
);
394 #ifdef SLUB_DEBUG_CMPXCHG
395 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
401 static inline bool cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
402 void *freelist_old
, unsigned long counters_old
,
403 void *freelist_new
, unsigned long counters_new
,
406 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
407 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
408 if (s
->flags
& __CMPXCHG_DOUBLE
) {
409 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
410 freelist_old
, counters_old
,
411 freelist_new
, counters_new
))
418 local_irq_save(flags
);
420 if (page
->freelist
== freelist_old
&&
421 page
->counters
== counters_old
) {
422 page
->freelist
= freelist_new
;
423 set_page_slub_counters(page
, counters_new
);
425 local_irq_restore(flags
);
429 local_irq_restore(flags
);
433 stat(s
, CMPXCHG_DOUBLE_FAIL
);
435 #ifdef SLUB_DEBUG_CMPXCHG
436 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
442 #ifdef CONFIG_SLUB_DEBUG
444 * Determine a map of object in use on a page.
446 * Node listlock must be held to guarantee that the page does
447 * not vanish from under us.
449 static void get_map(struct kmem_cache
*s
, struct page
*page
, unsigned long *map
)
452 void *addr
= page_address(page
);
454 for (p
= page
->freelist
; p
; p
= get_freepointer(s
, p
))
455 set_bit(slab_index(p
, s
, addr
), map
);
461 #ifdef CONFIG_SLUB_DEBUG_ON
462 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
464 static int slub_debug
;
467 static char *slub_debug_slabs
;
468 static int disable_higher_order_debug
;
473 static void print_section(char *text
, u8
*addr
, unsigned int length
)
475 print_hex_dump(KERN_ERR
, text
, DUMP_PREFIX_ADDRESS
, 16, 1, addr
,
479 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
480 enum track_item alloc
)
485 p
= object
+ s
->offset
+ sizeof(void *);
487 p
= object
+ s
->inuse
;
492 static void set_track(struct kmem_cache
*s
, void *object
,
493 enum track_item alloc
, unsigned long addr
)
495 struct track
*p
= get_track(s
, object
, alloc
);
498 #ifdef CONFIG_STACKTRACE
499 struct stack_trace trace
;
502 trace
.nr_entries
= 0;
503 trace
.max_entries
= TRACK_ADDRS_COUNT
;
504 trace
.entries
= p
->addrs
;
506 save_stack_trace(&trace
);
508 /* See rant in lockdep.c */
509 if (trace
.nr_entries
!= 0 &&
510 trace
.entries
[trace
.nr_entries
- 1] == ULONG_MAX
)
513 for (i
= trace
.nr_entries
; i
< TRACK_ADDRS_COUNT
; i
++)
517 p
->cpu
= smp_processor_id();
518 p
->pid
= current
->pid
;
521 memset(p
, 0, sizeof(struct track
));
524 static void init_tracking(struct kmem_cache
*s
, void *object
)
526 if (!(s
->flags
& SLAB_STORE_USER
))
529 set_track(s
, object
, TRACK_FREE
, 0UL);
530 set_track(s
, object
, TRACK_ALLOC
, 0UL);
533 static void print_track(const char *s
, struct track
*t
)
538 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
539 s
, (void *)t
->addr
, jiffies
- t
->when
, t
->cpu
, t
->pid
);
540 #ifdef CONFIG_STACKTRACE
543 for (i
= 0; i
< TRACK_ADDRS_COUNT
; i
++)
545 pr_err("\t%pS\n", (void *)t
->addrs
[i
]);
552 static void print_tracking(struct kmem_cache
*s
, void *object
)
554 if (!(s
->flags
& SLAB_STORE_USER
))
557 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
558 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
561 static void print_page_info(struct page
*page
)
563 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
564 page
, page
->objects
, page
->inuse
, page
->freelist
, page
->flags
);
568 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
570 struct va_format vaf
;
576 pr_err("=============================================================================\n");
577 pr_err("BUG %s (%s): %pV\n", s
->name
, print_tainted(), &vaf
);
578 pr_err("-----------------------------------------------------------------------------\n\n");
580 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
584 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
586 struct va_format vaf
;
592 pr_err("FIX %s: %pV\n", s
->name
, &vaf
);
596 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
598 unsigned int off
; /* Offset of last byte */
599 u8
*addr
= page_address(page
);
601 print_tracking(s
, p
);
603 print_page_info(page
);
605 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
606 p
, p
- addr
, get_freepointer(s
, p
));
609 print_section("Bytes b4 ", p
- 16, 16);
611 print_section("Object ", p
, min_t(unsigned long, s
->object_size
,
613 if (s
->flags
& SLAB_RED_ZONE
)
614 print_section("Redzone ", p
+ s
->object_size
,
615 s
->inuse
- s
->object_size
);
618 off
= s
->offset
+ sizeof(void *);
622 if (s
->flags
& SLAB_STORE_USER
)
623 off
+= 2 * sizeof(struct track
);
626 /* Beginning of the filler is the free pointer */
627 print_section("Padding ", p
+ off
, s
->size
- off
);
632 static void object_err(struct kmem_cache
*s
, struct page
*page
,
633 u8
*object
, char *reason
)
635 slab_bug(s
, "%s", reason
);
636 print_trailer(s
, page
, object
);
639 static void slab_err(struct kmem_cache
*s
, struct page
*page
,
640 const char *fmt
, ...)
646 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
648 slab_bug(s
, "%s", buf
);
649 print_page_info(page
);
653 static void init_object(struct kmem_cache
*s
, void *object
, u8 val
)
657 if (s
->flags
& __OBJECT_POISON
) {
658 memset(p
, POISON_FREE
, s
->object_size
- 1);
659 p
[s
->object_size
- 1] = POISON_END
;
662 if (s
->flags
& SLAB_RED_ZONE
)
663 memset(p
+ s
->object_size
, val
, s
->inuse
- s
->object_size
);
666 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
667 void *from
, void *to
)
669 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
670 memset(from
, data
, to
- from
);
673 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
674 u8
*object
, char *what
,
675 u8
*start
, unsigned int value
, unsigned int bytes
)
680 fault
= memchr_inv(start
, value
, bytes
);
685 while (end
> fault
&& end
[-1] == value
)
688 slab_bug(s
, "%s overwritten", what
);
689 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
690 fault
, end
- 1, fault
[0], value
);
691 print_trailer(s
, page
, object
);
693 restore_bytes(s
, what
, value
, fault
, end
);
701 * Bytes of the object to be managed.
702 * If the freepointer may overlay the object then the free
703 * pointer is the first word of the object.
705 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
708 * object + s->object_size
709 * Padding to reach word boundary. This is also used for Redzoning.
710 * Padding is extended by another word if Redzoning is enabled and
711 * object_size == inuse.
713 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
714 * 0xcc (RED_ACTIVE) for objects in use.
717 * Meta data starts here.
719 * A. Free pointer (if we cannot overwrite object on free)
720 * B. Tracking data for SLAB_STORE_USER
721 * C. Padding to reach required alignment boundary or at mininum
722 * one word if debugging is on to be able to detect writes
723 * before the word boundary.
725 * Padding is done using 0x5a (POISON_INUSE)
728 * Nothing is used beyond s->size.
730 * If slabcaches are merged then the object_size and inuse boundaries are mostly
731 * ignored. And therefore no slab options that rely on these boundaries
732 * may be used with merged slabcaches.
735 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
737 unsigned long off
= s
->inuse
; /* The end of info */
740 /* Freepointer is placed after the object. */
741 off
+= sizeof(void *);
743 if (s
->flags
& SLAB_STORE_USER
)
744 /* We also have user information there */
745 off
+= 2 * sizeof(struct track
);
750 return check_bytes_and_report(s
, page
, p
, "Object padding",
751 p
+ off
, POISON_INUSE
, s
->size
- off
);
754 /* Check the pad bytes at the end of a slab page */
755 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
763 if (!(s
->flags
& SLAB_POISON
))
766 start
= page_address(page
);
767 length
= (PAGE_SIZE
<< compound_order(page
)) - s
->reserved
;
768 end
= start
+ length
;
769 remainder
= length
% s
->size
;
773 fault
= memchr_inv(end
- remainder
, POISON_INUSE
, remainder
);
776 while (end
> fault
&& end
[-1] == POISON_INUSE
)
779 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
780 print_section("Padding ", end
- remainder
, remainder
);
782 restore_bytes(s
, "slab padding", POISON_INUSE
, end
- remainder
, end
);
786 static int check_object(struct kmem_cache
*s
, struct page
*page
,
787 void *object
, u8 val
)
790 u8
*endobject
= object
+ s
->object_size
;
792 if (s
->flags
& SLAB_RED_ZONE
) {
793 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
794 endobject
, val
, s
->inuse
- s
->object_size
))
797 if ((s
->flags
& SLAB_POISON
) && s
->object_size
< s
->inuse
) {
798 check_bytes_and_report(s
, page
, p
, "Alignment padding",
799 endobject
, POISON_INUSE
,
800 s
->inuse
- s
->object_size
);
804 if (s
->flags
& SLAB_POISON
) {
805 if (val
!= SLUB_RED_ACTIVE
&& (s
->flags
& __OBJECT_POISON
) &&
806 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
807 POISON_FREE
, s
->object_size
- 1) ||
808 !check_bytes_and_report(s
, page
, p
, "Poison",
809 p
+ s
->object_size
- 1, POISON_END
, 1)))
812 * check_pad_bytes cleans up on its own.
814 check_pad_bytes(s
, page
, p
);
817 if (!s
->offset
&& val
== SLUB_RED_ACTIVE
)
819 * Object and freepointer overlap. Cannot check
820 * freepointer while object is allocated.
824 /* Check free pointer validity */
825 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
826 object_err(s
, page
, p
, "Freepointer corrupt");
828 * No choice but to zap it and thus lose the remainder
829 * of the free objects in this slab. May cause
830 * another error because the object count is now wrong.
832 set_freepointer(s
, p
, NULL
);
838 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
842 VM_BUG_ON(!irqs_disabled());
844 if (!PageSlab(page
)) {
845 slab_err(s
, page
, "Not a valid slab page");
849 maxobj
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
850 if (page
->objects
> maxobj
) {
851 slab_err(s
, page
, "objects %u > max %u",
852 page
->objects
, maxobj
);
855 if (page
->inuse
> page
->objects
) {
856 slab_err(s
, page
, "inuse %u > max %u",
857 page
->inuse
, page
->objects
);
860 /* Slab_pad_check fixes things up after itself */
861 slab_pad_check(s
, page
);
866 * Determine if a certain object on a page is on the freelist. Must hold the
867 * slab lock to guarantee that the chains are in a consistent state.
869 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
877 while (fp
&& nr
<= page
->objects
) {
880 if (!check_valid_pointer(s
, page
, fp
)) {
882 object_err(s
, page
, object
,
883 "Freechain corrupt");
884 set_freepointer(s
, object
, NULL
);
886 slab_err(s
, page
, "Freepointer corrupt");
887 page
->freelist
= NULL
;
888 page
->inuse
= page
->objects
;
889 slab_fix(s
, "Freelist cleared");
895 fp
= get_freepointer(s
, object
);
899 max_objects
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
900 if (max_objects
> MAX_OBJS_PER_PAGE
)
901 max_objects
= MAX_OBJS_PER_PAGE
;
903 if (page
->objects
!= max_objects
) {
904 slab_err(s
, page
, "Wrong number of objects. Found %d but "
905 "should be %d", page
->objects
, max_objects
);
906 page
->objects
= max_objects
;
907 slab_fix(s
, "Number of objects adjusted.");
909 if (page
->inuse
!= page
->objects
- nr
) {
910 slab_err(s
, page
, "Wrong object count. Counter is %d but "
911 "counted were %d", page
->inuse
, page
->objects
- nr
);
912 page
->inuse
= page
->objects
- nr
;
913 slab_fix(s
, "Object count adjusted.");
915 return search
== NULL
;
918 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
,
921 if (s
->flags
& SLAB_TRACE
) {
922 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
924 alloc
? "alloc" : "free",
929 print_section("Object ", (void *)object
,
937 * Tracking of fully allocated slabs for debugging purposes.
939 static void add_full(struct kmem_cache
*s
,
940 struct kmem_cache_node
*n
, struct page
*page
)
942 if (!(s
->flags
& SLAB_STORE_USER
))
945 lockdep_assert_held(&n
->list_lock
);
946 list_add(&page
->lru
, &n
->full
);
949 static void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
, struct page
*page
)
951 if (!(s
->flags
& SLAB_STORE_USER
))
954 lockdep_assert_held(&n
->list_lock
);
955 list_del(&page
->lru
);
958 /* Tracking of the number of slabs for debugging purposes */
959 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
961 struct kmem_cache_node
*n
= get_node(s
, node
);
963 return atomic_long_read(&n
->nr_slabs
);
966 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
968 return atomic_long_read(&n
->nr_slabs
);
971 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
973 struct kmem_cache_node
*n
= get_node(s
, node
);
976 * May be called early in order to allocate a slab for the
977 * kmem_cache_node structure. Solve the chicken-egg
978 * dilemma by deferring the increment of the count during
979 * bootstrap (see early_kmem_cache_node_alloc).
982 atomic_long_inc(&n
->nr_slabs
);
983 atomic_long_add(objects
, &n
->total_objects
);
986 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
988 struct kmem_cache_node
*n
= get_node(s
, node
);
990 atomic_long_dec(&n
->nr_slabs
);
991 atomic_long_sub(objects
, &n
->total_objects
);
994 /* Object debug checks for alloc/free paths */
995 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
998 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
1001 init_object(s
, object
, SLUB_RED_INACTIVE
);
1002 init_tracking(s
, object
);
1005 static noinline
int alloc_debug_processing(struct kmem_cache
*s
,
1007 void *object
, unsigned long addr
)
1009 if (!check_slab(s
, page
))
1012 if (!check_valid_pointer(s
, page
, object
)) {
1013 object_err(s
, page
, object
, "Freelist Pointer check fails");
1017 if (!check_object(s
, page
, object
, SLUB_RED_INACTIVE
))
1020 /* Success perform special debug activities for allocs */
1021 if (s
->flags
& SLAB_STORE_USER
)
1022 set_track(s
, object
, TRACK_ALLOC
, addr
);
1023 trace(s
, page
, object
, 1);
1024 init_object(s
, object
, SLUB_RED_ACTIVE
);
1028 if (PageSlab(page
)) {
1030 * If this is a slab page then lets do the best we can
1031 * to avoid issues in the future. Marking all objects
1032 * as used avoids touching the remaining objects.
1034 slab_fix(s
, "Marking all objects used");
1035 page
->inuse
= page
->objects
;
1036 page
->freelist
= NULL
;
1041 static noinline
struct kmem_cache_node
*free_debug_processing(
1042 struct kmem_cache
*s
, struct page
*page
, void *object
,
1043 unsigned long addr
, unsigned long *flags
)
1045 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1047 spin_lock_irqsave(&n
->list_lock
, *flags
);
1050 if (!check_slab(s
, page
))
1053 if (!check_valid_pointer(s
, page
, object
)) {
1054 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
1058 if (on_freelist(s
, page
, object
)) {
1059 object_err(s
, page
, object
, "Object already free");
1063 if (!check_object(s
, page
, object
, SLUB_RED_ACTIVE
))
1066 if (unlikely(s
!= page
->slab_cache
)) {
1067 if (!PageSlab(page
)) {
1068 slab_err(s
, page
, "Attempt to free object(0x%p) "
1069 "outside of slab", object
);
1070 } else if (!page
->slab_cache
) {
1071 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1075 object_err(s
, page
, object
,
1076 "page slab pointer corrupt.");
1080 if (s
->flags
& SLAB_STORE_USER
)
1081 set_track(s
, object
, TRACK_FREE
, addr
);
1082 trace(s
, page
, object
, 0);
1083 init_object(s
, object
, SLUB_RED_INACTIVE
);
1087 * Keep node_lock to preserve integrity
1088 * until the object is actually freed
1094 spin_unlock_irqrestore(&n
->list_lock
, *flags
);
1095 slab_fix(s
, "Object at 0x%p not freed", object
);
1099 static int __init
setup_slub_debug(char *str
)
1101 slub_debug
= DEBUG_DEFAULT_FLAGS
;
1102 if (*str
++ != '=' || !*str
)
1104 * No options specified. Switch on full debugging.
1110 * No options but restriction on slabs. This means full
1111 * debugging for slabs matching a pattern.
1115 if (tolower(*str
) == 'o') {
1117 * Avoid enabling debugging on caches if its minimum order
1118 * would increase as a result.
1120 disable_higher_order_debug
= 1;
1127 * Switch off all debugging measures.
1132 * Determine which debug features should be switched on
1134 for (; *str
&& *str
!= ','; str
++) {
1135 switch (tolower(*str
)) {
1137 slub_debug
|= SLAB_DEBUG_FREE
;
1140 slub_debug
|= SLAB_RED_ZONE
;
1143 slub_debug
|= SLAB_POISON
;
1146 slub_debug
|= SLAB_STORE_USER
;
1149 slub_debug
|= SLAB_TRACE
;
1152 slub_debug
|= SLAB_FAILSLAB
;
1155 pr_err("slub_debug option '%c' unknown. skipped\n",
1162 slub_debug_slabs
= str
+ 1;
1167 __setup("slub_debug", setup_slub_debug
);
1169 unsigned long kmem_cache_flags(unsigned long object_size
,
1170 unsigned long flags
, const char *name
,
1171 void (*ctor
)(void *))
1174 * Enable debugging if selected on the kernel commandline.
1176 if (slub_debug
&& (!slub_debug_slabs
|| (name
&&
1177 !strncmp(slub_debug_slabs
, name
, strlen(slub_debug_slabs
)))))
1178 flags
|= slub_debug
;
1183 static inline void setup_object_debug(struct kmem_cache
*s
,
1184 struct page
*page
, void *object
) {}
1186 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1187 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1189 static inline struct kmem_cache_node
*free_debug_processing(
1190 struct kmem_cache
*s
, struct page
*page
, void *object
,
1191 unsigned long addr
, unsigned long *flags
) { return NULL
; }
1193 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1195 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1196 void *object
, u8 val
) { return 1; }
1197 static inline void add_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1198 struct page
*page
) {}
1199 static inline void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1200 struct page
*page
) {}
1201 unsigned long kmem_cache_flags(unsigned long object_size
,
1202 unsigned long flags
, const char *name
,
1203 void (*ctor
)(void *))
1207 #define slub_debug 0
1209 #define disable_higher_order_debug 0
1211 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1213 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1215 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
,
1217 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
,
1220 #endif /* CONFIG_SLUB_DEBUG */
1223 * Hooks for other subsystems that check memory allocations. In a typical
1224 * production configuration these hooks all should produce no code at all.
1226 static inline void kmalloc_large_node_hook(void *ptr
, size_t size
, gfp_t flags
)
1228 kmemleak_alloc(ptr
, size
, 1, flags
);
1231 static inline void kfree_hook(const void *x
)
1236 static inline int slab_pre_alloc_hook(struct kmem_cache
*s
, gfp_t flags
)
1238 flags
&= gfp_allowed_mask
;
1239 lockdep_trace_alloc(flags
);
1240 might_sleep_if(flags
& __GFP_WAIT
);
1242 return should_failslab(s
->object_size
, flags
, s
->flags
);
1245 static inline void slab_post_alloc_hook(struct kmem_cache
*s
,
1246 gfp_t flags
, void *object
)
1248 flags
&= gfp_allowed_mask
;
1249 kmemcheck_slab_alloc(s
, flags
, object
, slab_ksize(s
));
1250 kmemleak_alloc_recursive(object
, s
->object_size
, 1, s
->flags
, flags
);
1253 static inline void slab_free_hook(struct kmem_cache
*s
, void *x
)
1255 kmemleak_free_recursive(x
, s
->flags
);
1258 * Trouble is that we may no longer disable interrupts in the fast path
1259 * So in order to make the debug calls that expect irqs to be
1260 * disabled we need to disable interrupts temporarily.
1262 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1264 unsigned long flags
;
1266 local_irq_save(flags
);
1267 kmemcheck_slab_free(s
, x
, s
->object_size
);
1268 debug_check_no_locks_freed(x
, s
->object_size
);
1269 local_irq_restore(flags
);
1272 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
1273 debug_check_no_obj_freed(x
, s
->object_size
);
1277 * Slab allocation and freeing
1279 static inline struct page
*alloc_slab_page(struct kmem_cache
*s
,
1280 gfp_t flags
, int node
, struct kmem_cache_order_objects oo
)
1283 int order
= oo_order(oo
);
1285 flags
|= __GFP_NOTRACK
;
1287 if (memcg_charge_slab(s
, flags
, order
))
1290 if (node
== NUMA_NO_NODE
)
1291 page
= alloc_pages(flags
, order
);
1293 page
= alloc_pages_exact_node(node
, flags
, order
);
1296 memcg_uncharge_slab(s
, order
);
1301 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1304 struct kmem_cache_order_objects oo
= s
->oo
;
1307 flags
&= gfp_allowed_mask
;
1309 if (flags
& __GFP_WAIT
)
1312 flags
|= s
->allocflags
;
1315 * Let the initial higher-order allocation fail under memory pressure
1316 * so we fall-back to the minimum order allocation.
1318 alloc_gfp
= (flags
| __GFP_NOWARN
| __GFP_NORETRY
) & ~__GFP_NOFAIL
;
1320 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1321 if (unlikely(!page
)) {
1325 * Allocation may have failed due to fragmentation.
1326 * Try a lower order alloc if possible
1328 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1331 stat(s
, ORDER_FALLBACK
);
1334 if (kmemcheck_enabled
&& page
1335 && !(s
->flags
& (SLAB_NOTRACK
| DEBUG_DEFAULT_FLAGS
))) {
1336 int pages
= 1 << oo_order(oo
);
1338 kmemcheck_alloc_shadow(page
, oo_order(oo
), alloc_gfp
, node
);
1341 * Objects from caches that have a constructor don't get
1342 * cleared when they're allocated, so we need to do it here.
1345 kmemcheck_mark_uninitialized_pages(page
, pages
);
1347 kmemcheck_mark_unallocated_pages(page
, pages
);
1350 if (flags
& __GFP_WAIT
)
1351 local_irq_disable();
1355 page
->objects
= oo_objects(oo
);
1356 mod_zone_page_state(page_zone(page
),
1357 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1358 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1364 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1367 setup_object_debug(s
, page
, object
);
1368 if (unlikely(s
->ctor
))
1372 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1380 if (unlikely(flags
& GFP_SLAB_BUG_MASK
)) {
1381 pr_emerg("gfp: %u\n", flags
& GFP_SLAB_BUG_MASK
);
1385 page
= allocate_slab(s
,
1386 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1390 order
= compound_order(page
);
1391 inc_slabs_node(s
, page_to_nid(page
), page
->objects
);
1392 page
->slab_cache
= s
;
1393 __SetPageSlab(page
);
1394 if (page
->pfmemalloc
)
1395 SetPageSlabPfmemalloc(page
);
1397 start
= page_address(page
);
1399 if (unlikely(s
->flags
& SLAB_POISON
))
1400 memset(start
, POISON_INUSE
, PAGE_SIZE
<< order
);
1402 for_each_object_idx(p
, idx
, s
, start
, page
->objects
) {
1403 setup_object(s
, page
, p
);
1404 if (likely(idx
< page
->objects
))
1405 set_freepointer(s
, p
, p
+ s
->size
);
1407 set_freepointer(s
, p
, NULL
);
1410 page
->freelist
= start
;
1411 page
->inuse
= page
->objects
;
1417 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1419 int order
= compound_order(page
);
1420 int pages
= 1 << order
;
1422 if (kmem_cache_debug(s
)) {
1425 slab_pad_check(s
, page
);
1426 for_each_object(p
, s
, page_address(page
),
1428 check_object(s
, page
, p
, SLUB_RED_INACTIVE
);
1431 kmemcheck_free_shadow(page
, compound_order(page
));
1433 mod_zone_page_state(page_zone(page
),
1434 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1435 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1438 __ClearPageSlabPfmemalloc(page
);
1439 __ClearPageSlab(page
);
1441 page_mapcount_reset(page
);
1442 if (current
->reclaim_state
)
1443 current
->reclaim_state
->reclaimed_slab
+= pages
;
1444 __free_pages(page
, order
);
1445 memcg_uncharge_slab(s
, order
);
1448 #define need_reserve_slab_rcu \
1449 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1451 static void rcu_free_slab(struct rcu_head
*h
)
1455 if (need_reserve_slab_rcu
)
1456 page
= virt_to_head_page(h
);
1458 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1460 __free_slab(page
->slab_cache
, page
);
1463 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1465 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1466 struct rcu_head
*head
;
1468 if (need_reserve_slab_rcu
) {
1469 int order
= compound_order(page
);
1470 int offset
= (PAGE_SIZE
<< order
) - s
->reserved
;
1472 VM_BUG_ON(s
->reserved
!= sizeof(*head
));
1473 head
= page_address(page
) + offset
;
1476 * RCU free overloads the RCU head over the LRU
1478 head
= (void *)&page
->lru
;
1481 call_rcu(head
, rcu_free_slab
);
1483 __free_slab(s
, page
);
1486 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1488 dec_slabs_node(s
, page_to_nid(page
), page
->objects
);
1493 * Management of partially allocated slabs.
1496 __add_partial(struct kmem_cache_node
*n
, struct page
*page
, int tail
)
1499 if (tail
== DEACTIVATE_TO_TAIL
)
1500 list_add_tail(&page
->lru
, &n
->partial
);
1502 list_add(&page
->lru
, &n
->partial
);
1505 static inline void add_partial(struct kmem_cache_node
*n
,
1506 struct page
*page
, int tail
)
1508 lockdep_assert_held(&n
->list_lock
);
1509 __add_partial(n
, page
, tail
);
1513 __remove_partial(struct kmem_cache_node
*n
, struct page
*page
)
1515 list_del(&page
->lru
);
1519 static inline void remove_partial(struct kmem_cache_node
*n
,
1522 lockdep_assert_held(&n
->list_lock
);
1523 __remove_partial(n
, page
);
1527 * Remove slab from the partial list, freeze it and
1528 * return the pointer to the freelist.
1530 * Returns a list of objects or NULL if it fails.
1532 static inline void *acquire_slab(struct kmem_cache
*s
,
1533 struct kmem_cache_node
*n
, struct page
*page
,
1534 int mode
, int *objects
)
1537 unsigned long counters
;
1540 lockdep_assert_held(&n
->list_lock
);
1543 * Zap the freelist and set the frozen bit.
1544 * The old freelist is the list of objects for the
1545 * per cpu allocation list.
1547 freelist
= page
->freelist
;
1548 counters
= page
->counters
;
1549 new.counters
= counters
;
1550 *objects
= new.objects
- new.inuse
;
1552 new.inuse
= page
->objects
;
1553 new.freelist
= NULL
;
1555 new.freelist
= freelist
;
1558 VM_BUG_ON(new.frozen
);
1561 if (!__cmpxchg_double_slab(s
, page
,
1563 new.freelist
, new.counters
,
1567 remove_partial(n
, page
);
1572 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
);
1573 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
);
1576 * Try to allocate a partial slab from a specific node.
1578 static void *get_partial_node(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1579 struct kmem_cache_cpu
*c
, gfp_t flags
)
1581 struct page
*page
, *page2
;
1582 void *object
= NULL
;
1587 * Racy check. If we mistakenly see no partial slabs then we
1588 * just allocate an empty slab. If we mistakenly try to get a
1589 * partial slab and there is none available then get_partials()
1592 if (!n
|| !n
->nr_partial
)
1595 spin_lock(&n
->list_lock
);
1596 list_for_each_entry_safe(page
, page2
, &n
->partial
, lru
) {
1599 if (!pfmemalloc_match(page
, flags
))
1602 t
= acquire_slab(s
, n
, page
, object
== NULL
, &objects
);
1606 available
+= objects
;
1609 stat(s
, ALLOC_FROM_PARTIAL
);
1612 put_cpu_partial(s
, page
, 0);
1613 stat(s
, CPU_PARTIAL_NODE
);
1615 if (!kmem_cache_has_cpu_partial(s
)
1616 || available
> s
->cpu_partial
/ 2)
1620 spin_unlock(&n
->list_lock
);
1625 * Get a page from somewhere. Search in increasing NUMA distances.
1627 static void *get_any_partial(struct kmem_cache
*s
, gfp_t flags
,
1628 struct kmem_cache_cpu
*c
)
1631 struct zonelist
*zonelist
;
1634 enum zone_type high_zoneidx
= gfp_zone(flags
);
1636 unsigned int cpuset_mems_cookie
;
1639 * The defrag ratio allows a configuration of the tradeoffs between
1640 * inter node defragmentation and node local allocations. A lower
1641 * defrag_ratio increases the tendency to do local allocations
1642 * instead of attempting to obtain partial slabs from other nodes.
1644 * If the defrag_ratio is set to 0 then kmalloc() always
1645 * returns node local objects. If the ratio is higher then kmalloc()
1646 * may return off node objects because partial slabs are obtained
1647 * from other nodes and filled up.
1649 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1650 * defrag_ratio = 1000) then every (well almost) allocation will
1651 * first attempt to defrag slab caches on other nodes. This means
1652 * scanning over all nodes to look for partial slabs which may be
1653 * expensive if we do it every time we are trying to find a slab
1654 * with available objects.
1656 if (!s
->remote_node_defrag_ratio
||
1657 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1661 cpuset_mems_cookie
= read_mems_allowed_begin();
1662 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
1663 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
1664 struct kmem_cache_node
*n
;
1666 n
= get_node(s
, zone_to_nid(zone
));
1668 if (n
&& cpuset_zone_allowed(zone
,
1669 flags
| __GFP_HARDWALL
) &&
1670 n
->nr_partial
> s
->min_partial
) {
1671 object
= get_partial_node(s
, n
, c
, flags
);
1674 * Don't check read_mems_allowed_retry()
1675 * here - if mems_allowed was updated in
1676 * parallel, that was a harmless race
1677 * between allocation and the cpuset
1684 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1690 * Get a partial page, lock it and return it.
1692 static void *get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
,
1693 struct kmem_cache_cpu
*c
)
1696 int searchnode
= node
;
1698 if (node
== NUMA_NO_NODE
)
1699 searchnode
= numa_mem_id();
1700 else if (!node_present_pages(node
))
1701 searchnode
= node_to_mem_node(node
);
1703 object
= get_partial_node(s
, get_node(s
, searchnode
), c
, flags
);
1704 if (object
|| node
!= NUMA_NO_NODE
)
1707 return get_any_partial(s
, flags
, c
);
1710 #ifdef CONFIG_PREEMPT
1712 * Calculate the next globally unique transaction for disambiguiation
1713 * during cmpxchg. The transactions start with the cpu number and are then
1714 * incremented by CONFIG_NR_CPUS.
1716 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1719 * No preemption supported therefore also no need to check for
1725 static inline unsigned long next_tid(unsigned long tid
)
1727 return tid
+ TID_STEP
;
1730 static inline unsigned int tid_to_cpu(unsigned long tid
)
1732 return tid
% TID_STEP
;
1735 static inline unsigned long tid_to_event(unsigned long tid
)
1737 return tid
/ TID_STEP
;
1740 static inline unsigned int init_tid(int cpu
)
1745 static inline void note_cmpxchg_failure(const char *n
,
1746 const struct kmem_cache
*s
, unsigned long tid
)
1748 #ifdef SLUB_DEBUG_CMPXCHG
1749 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
1751 pr_info("%s %s: cmpxchg redo ", n
, s
->name
);
1753 #ifdef CONFIG_PREEMPT
1754 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
1755 pr_warn("due to cpu change %d -> %d\n",
1756 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
1759 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
1760 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1761 tid_to_event(tid
), tid_to_event(actual_tid
));
1763 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1764 actual_tid
, tid
, next_tid(tid
));
1766 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
1769 static void init_kmem_cache_cpus(struct kmem_cache
*s
)
1773 for_each_possible_cpu(cpu
)
1774 per_cpu_ptr(s
->cpu_slab
, cpu
)->tid
= init_tid(cpu
);
1778 * Remove the cpu slab
1780 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
,
1783 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
1784 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1786 enum slab_modes l
= M_NONE
, m
= M_NONE
;
1788 int tail
= DEACTIVATE_TO_HEAD
;
1792 if (page
->freelist
) {
1793 stat(s
, DEACTIVATE_REMOTE_FREES
);
1794 tail
= DEACTIVATE_TO_TAIL
;
1798 * Stage one: Free all available per cpu objects back
1799 * to the page freelist while it is still frozen. Leave the
1802 * There is no need to take the list->lock because the page
1805 while (freelist
&& (nextfree
= get_freepointer(s
, freelist
))) {
1807 unsigned long counters
;
1810 prior
= page
->freelist
;
1811 counters
= page
->counters
;
1812 set_freepointer(s
, freelist
, prior
);
1813 new.counters
= counters
;
1815 VM_BUG_ON(!new.frozen
);
1817 } while (!__cmpxchg_double_slab(s
, page
,
1819 freelist
, new.counters
,
1820 "drain percpu freelist"));
1822 freelist
= nextfree
;
1826 * Stage two: Ensure that the page is unfrozen while the
1827 * list presence reflects the actual number of objects
1830 * We setup the list membership and then perform a cmpxchg
1831 * with the count. If there is a mismatch then the page
1832 * is not unfrozen but the page is on the wrong list.
1834 * Then we restart the process which may have to remove
1835 * the page from the list that we just put it on again
1836 * because the number of objects in the slab may have
1841 old
.freelist
= page
->freelist
;
1842 old
.counters
= page
->counters
;
1843 VM_BUG_ON(!old
.frozen
);
1845 /* Determine target state of the slab */
1846 new.counters
= old
.counters
;
1849 set_freepointer(s
, freelist
, old
.freelist
);
1850 new.freelist
= freelist
;
1852 new.freelist
= old
.freelist
;
1856 if (!new.inuse
&& n
->nr_partial
>= s
->min_partial
)
1858 else if (new.freelist
) {
1863 * Taking the spinlock removes the possiblity
1864 * that acquire_slab() will see a slab page that
1867 spin_lock(&n
->list_lock
);
1871 if (kmem_cache_debug(s
) && !lock
) {
1874 * This also ensures that the scanning of full
1875 * slabs from diagnostic functions will not see
1878 spin_lock(&n
->list_lock
);
1886 remove_partial(n
, page
);
1888 else if (l
== M_FULL
)
1890 remove_full(s
, n
, page
);
1892 if (m
== M_PARTIAL
) {
1894 add_partial(n
, page
, tail
);
1897 } else if (m
== M_FULL
) {
1899 stat(s
, DEACTIVATE_FULL
);
1900 add_full(s
, n
, page
);
1906 if (!__cmpxchg_double_slab(s
, page
,
1907 old
.freelist
, old
.counters
,
1908 new.freelist
, new.counters
,
1913 spin_unlock(&n
->list_lock
);
1916 stat(s
, DEACTIVATE_EMPTY
);
1917 discard_slab(s
, page
);
1923 * Unfreeze all the cpu partial slabs.
1925 * This function must be called with interrupts disabled
1926 * for the cpu using c (or some other guarantee must be there
1927 * to guarantee no concurrent accesses).
1929 static void unfreeze_partials(struct kmem_cache
*s
,
1930 struct kmem_cache_cpu
*c
)
1932 #ifdef CONFIG_SLUB_CPU_PARTIAL
1933 struct kmem_cache_node
*n
= NULL
, *n2
= NULL
;
1934 struct page
*page
, *discard_page
= NULL
;
1936 while ((page
= c
->partial
)) {
1940 c
->partial
= page
->next
;
1942 n2
= get_node(s
, page_to_nid(page
));
1945 spin_unlock(&n
->list_lock
);
1948 spin_lock(&n
->list_lock
);
1953 old
.freelist
= page
->freelist
;
1954 old
.counters
= page
->counters
;
1955 VM_BUG_ON(!old
.frozen
);
1957 new.counters
= old
.counters
;
1958 new.freelist
= old
.freelist
;
1962 } while (!__cmpxchg_double_slab(s
, page
,
1963 old
.freelist
, old
.counters
,
1964 new.freelist
, new.counters
,
1965 "unfreezing slab"));
1967 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
)) {
1968 page
->next
= discard_page
;
1969 discard_page
= page
;
1971 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
1972 stat(s
, FREE_ADD_PARTIAL
);
1977 spin_unlock(&n
->list_lock
);
1979 while (discard_page
) {
1980 page
= discard_page
;
1981 discard_page
= discard_page
->next
;
1983 stat(s
, DEACTIVATE_EMPTY
);
1984 discard_slab(s
, page
);
1991 * Put a page that was just frozen (in __slab_free) into a partial page
1992 * slot if available. This is done without interrupts disabled and without
1993 * preemption disabled. The cmpxchg is racy and may put the partial page
1994 * onto a random cpus partial slot.
1996 * If we did not find a slot then simply move all the partials to the
1997 * per node partial list.
1999 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
)
2001 #ifdef CONFIG_SLUB_CPU_PARTIAL
2002 struct page
*oldpage
;
2009 oldpage
= this_cpu_read(s
->cpu_slab
->partial
);
2012 pobjects
= oldpage
->pobjects
;
2013 pages
= oldpage
->pages
;
2014 if (drain
&& pobjects
> s
->cpu_partial
) {
2015 unsigned long flags
;
2017 * partial array is full. Move the existing
2018 * set to the per node partial list.
2020 local_irq_save(flags
);
2021 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2022 local_irq_restore(flags
);
2026 stat(s
, CPU_PARTIAL_DRAIN
);
2031 pobjects
+= page
->objects
- page
->inuse
;
2033 page
->pages
= pages
;
2034 page
->pobjects
= pobjects
;
2035 page
->next
= oldpage
;
2037 } while (this_cpu_cmpxchg(s
->cpu_slab
->partial
, oldpage
, page
)
2042 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
2044 stat(s
, CPUSLAB_FLUSH
);
2045 deactivate_slab(s
, c
->page
, c
->freelist
);
2047 c
->tid
= next_tid(c
->tid
);
2055 * Called from IPI handler with interrupts disabled.
2057 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
2059 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2065 unfreeze_partials(s
, c
);
2069 static void flush_cpu_slab(void *d
)
2071 struct kmem_cache
*s
= d
;
2073 __flush_cpu_slab(s
, smp_processor_id());
2076 static bool has_cpu_slab(int cpu
, void *info
)
2078 struct kmem_cache
*s
= info
;
2079 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2081 return c
->page
|| c
->partial
;
2084 static void flush_all(struct kmem_cache
*s
)
2086 on_each_cpu_cond(has_cpu_slab
, flush_cpu_slab
, s
, 1, GFP_ATOMIC
);
2090 * Check if the objects in a per cpu structure fit numa
2091 * locality expectations.
2093 static inline int node_match(struct page
*page
, int node
)
2096 if (!page
|| (node
!= NUMA_NO_NODE
&& page_to_nid(page
) != node
))
2102 #ifdef CONFIG_SLUB_DEBUG
2103 static int count_free(struct page
*page
)
2105 return page
->objects
- page
->inuse
;
2108 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
2110 return atomic_long_read(&n
->total_objects
);
2112 #endif /* CONFIG_SLUB_DEBUG */
2114 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2115 static unsigned long count_partial(struct kmem_cache_node
*n
,
2116 int (*get_count
)(struct page
*))
2118 unsigned long flags
;
2119 unsigned long x
= 0;
2122 spin_lock_irqsave(&n
->list_lock
, flags
);
2123 list_for_each_entry(page
, &n
->partial
, lru
)
2124 x
+= get_count(page
);
2125 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2128 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2130 static noinline
void
2131 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
2133 #ifdef CONFIG_SLUB_DEBUG
2134 static DEFINE_RATELIMIT_STATE(slub_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2135 DEFAULT_RATELIMIT_BURST
);
2137 struct kmem_cache_node
*n
;
2139 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slub_oom_rs
))
2142 pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2144 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2145 s
->name
, s
->object_size
, s
->size
, oo_order(s
->oo
),
2148 if (oo_order(s
->min
) > get_order(s
->object_size
))
2149 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2152 for_each_kmem_cache_node(s
, node
, n
) {
2153 unsigned long nr_slabs
;
2154 unsigned long nr_objs
;
2155 unsigned long nr_free
;
2157 nr_free
= count_partial(n
, count_free
);
2158 nr_slabs
= node_nr_slabs(n
);
2159 nr_objs
= node_nr_objs(n
);
2161 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2162 node
, nr_slabs
, nr_objs
, nr_free
);
2167 static inline void *new_slab_objects(struct kmem_cache
*s
, gfp_t flags
,
2168 int node
, struct kmem_cache_cpu
**pc
)
2171 struct kmem_cache_cpu
*c
= *pc
;
2174 freelist
= get_partial(s
, flags
, node
, c
);
2179 page
= new_slab(s
, flags
, node
);
2181 c
= raw_cpu_ptr(s
->cpu_slab
);
2186 * No other reference to the page yet so we can
2187 * muck around with it freely without cmpxchg
2189 freelist
= page
->freelist
;
2190 page
->freelist
= NULL
;
2192 stat(s
, ALLOC_SLAB
);
2201 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
)
2203 if (unlikely(PageSlabPfmemalloc(page
)))
2204 return gfp_pfmemalloc_allowed(gfpflags
);
2210 * Check the page->freelist of a page and either transfer the freelist to the
2211 * per cpu freelist or deactivate the page.
2213 * The page is still frozen if the return value is not NULL.
2215 * If this function returns NULL then the page has been unfrozen.
2217 * This function must be called with interrupt disabled.
2219 static inline void *get_freelist(struct kmem_cache
*s
, struct page
*page
)
2222 unsigned long counters
;
2226 freelist
= page
->freelist
;
2227 counters
= page
->counters
;
2229 new.counters
= counters
;
2230 VM_BUG_ON(!new.frozen
);
2232 new.inuse
= page
->objects
;
2233 new.frozen
= freelist
!= NULL
;
2235 } while (!__cmpxchg_double_slab(s
, page
,
2244 * Slow path. The lockless freelist is empty or we need to perform
2247 * Processing is still very fast if new objects have been freed to the
2248 * regular freelist. In that case we simply take over the regular freelist
2249 * as the lockless freelist and zap the regular freelist.
2251 * If that is not working then we fall back to the partial lists. We take the
2252 * first element of the freelist as the object to allocate now and move the
2253 * rest of the freelist to the lockless freelist.
2255 * And if we were unable to get a new slab from the partial slab lists then
2256 * we need to allocate a new slab. This is the slowest path since it involves
2257 * a call to the page allocator and the setup of a new slab.
2259 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2260 unsigned long addr
, struct kmem_cache_cpu
*c
)
2264 unsigned long flags
;
2266 local_irq_save(flags
);
2267 #ifdef CONFIG_PREEMPT
2269 * We may have been preempted and rescheduled on a different
2270 * cpu before disabling interrupts. Need to reload cpu area
2273 c
= this_cpu_ptr(s
->cpu_slab
);
2281 if (unlikely(!node_match(page
, node
))) {
2282 int searchnode
= node
;
2284 if (node
!= NUMA_NO_NODE
&& !node_present_pages(node
))
2285 searchnode
= node_to_mem_node(node
);
2287 if (unlikely(!node_match(page
, searchnode
))) {
2288 stat(s
, ALLOC_NODE_MISMATCH
);
2289 deactivate_slab(s
, page
, c
->freelist
);
2297 * By rights, we should be searching for a slab page that was
2298 * PFMEMALLOC but right now, we are losing the pfmemalloc
2299 * information when the page leaves the per-cpu allocator
2301 if (unlikely(!pfmemalloc_match(page
, gfpflags
))) {
2302 deactivate_slab(s
, page
, c
->freelist
);
2308 /* must check again c->freelist in case of cpu migration or IRQ */
2309 freelist
= c
->freelist
;
2313 freelist
= get_freelist(s
, page
);
2317 stat(s
, DEACTIVATE_BYPASS
);
2321 stat(s
, ALLOC_REFILL
);
2325 * freelist is pointing to the list of objects to be used.
2326 * page is pointing to the page from which the objects are obtained.
2327 * That page must be frozen for per cpu allocations to work.
2329 VM_BUG_ON(!c
->page
->frozen
);
2330 c
->freelist
= get_freepointer(s
, freelist
);
2331 c
->tid
= next_tid(c
->tid
);
2332 local_irq_restore(flags
);
2338 page
= c
->page
= c
->partial
;
2339 c
->partial
= page
->next
;
2340 stat(s
, CPU_PARTIAL_ALLOC
);
2345 freelist
= new_slab_objects(s
, gfpflags
, node
, &c
);
2347 if (unlikely(!freelist
)) {
2348 slab_out_of_memory(s
, gfpflags
, node
);
2349 local_irq_restore(flags
);
2354 if (likely(!kmem_cache_debug(s
) && pfmemalloc_match(page
, gfpflags
)))
2357 /* Only entered in the debug case */
2358 if (kmem_cache_debug(s
) &&
2359 !alloc_debug_processing(s
, page
, freelist
, addr
))
2360 goto new_slab
; /* Slab failed checks. Next slab needed */
2362 deactivate_slab(s
, page
, get_freepointer(s
, freelist
));
2365 local_irq_restore(flags
);
2370 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2371 * have the fastpath folded into their functions. So no function call
2372 * overhead for requests that can be satisfied on the fastpath.
2374 * The fastpath works by first checking if the lockless freelist can be used.
2375 * If not then __slab_alloc is called for slow processing.
2377 * Otherwise we can simply pick the next object from the lockless free list.
2379 static __always_inline
void *slab_alloc_node(struct kmem_cache
*s
,
2380 gfp_t gfpflags
, int node
, unsigned long addr
)
2383 struct kmem_cache_cpu
*c
;
2387 if (slab_pre_alloc_hook(s
, gfpflags
))
2390 s
= memcg_kmem_get_cache(s
, gfpflags
);
2393 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2394 * enabled. We may switch back and forth between cpus while
2395 * reading from one cpu area. That does not matter as long
2396 * as we end up on the original cpu again when doing the cmpxchg.
2398 * Preemption is disabled for the retrieval of the tid because that
2399 * must occur from the current processor. We cannot allow rescheduling
2400 * on a different processor between the determination of the pointer
2401 * and the retrieval of the tid.
2404 c
= this_cpu_ptr(s
->cpu_slab
);
2407 * The transaction ids are globally unique per cpu and per operation on
2408 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2409 * occurs on the right processor and that there was no operation on the
2410 * linked list in between.
2415 object
= c
->freelist
;
2417 if (unlikely(!object
|| !node_match(page
, node
))) {
2418 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
2419 stat(s
, ALLOC_SLOWPATH
);
2421 void *next_object
= get_freepointer_safe(s
, object
);
2424 * The cmpxchg will only match if there was no additional
2425 * operation and if we are on the right processor.
2427 * The cmpxchg does the following atomically (without lock
2429 * 1. Relocate first pointer to the current per cpu area.
2430 * 2. Verify that tid and freelist have not been changed
2431 * 3. If they were not changed replace tid and freelist
2433 * Since this is without lock semantics the protection is only
2434 * against code executing on this cpu *not* from access by
2437 if (unlikely(!this_cpu_cmpxchg_double(
2438 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2440 next_object
, next_tid(tid
)))) {
2442 note_cmpxchg_failure("slab_alloc", s
, tid
);
2445 prefetch_freepointer(s
, next_object
);
2446 stat(s
, ALLOC_FASTPATH
);
2449 if (unlikely(gfpflags
& __GFP_ZERO
) && object
)
2450 memset(object
, 0, s
->object_size
);
2452 slab_post_alloc_hook(s
, gfpflags
, object
);
2457 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
2458 gfp_t gfpflags
, unsigned long addr
)
2460 return slab_alloc_node(s
, gfpflags
, NUMA_NO_NODE
, addr
);
2463 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
2465 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2467 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->object_size
,
2472 EXPORT_SYMBOL(kmem_cache_alloc
);
2474 #ifdef CONFIG_TRACING
2475 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
2477 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2478 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
2481 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
2485 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
2487 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2489 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
2490 s
->object_size
, s
->size
, gfpflags
, node
);
2494 EXPORT_SYMBOL(kmem_cache_alloc_node
);
2496 #ifdef CONFIG_TRACING
2497 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
2499 int node
, size_t size
)
2501 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2503 trace_kmalloc_node(_RET_IP_
, ret
,
2504 size
, s
->size
, gfpflags
, node
);
2507 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
2512 * Slow patch handling. This may still be called frequently since objects
2513 * have a longer lifetime than the cpu slabs in most processing loads.
2515 * So we still attempt to reduce cache line usage. Just take the slab
2516 * lock and free the item. If there is no additional partial page
2517 * handling required then we can return immediately.
2519 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
2520 void *x
, unsigned long addr
)
2523 void **object
= (void *)x
;
2526 unsigned long counters
;
2527 struct kmem_cache_node
*n
= NULL
;
2528 unsigned long uninitialized_var(flags
);
2530 stat(s
, FREE_SLOWPATH
);
2532 if (kmem_cache_debug(s
) &&
2533 !(n
= free_debug_processing(s
, page
, x
, addr
, &flags
)))
2538 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2541 prior
= page
->freelist
;
2542 counters
= page
->counters
;
2543 set_freepointer(s
, object
, prior
);
2544 new.counters
= counters
;
2545 was_frozen
= new.frozen
;
2547 if ((!new.inuse
|| !prior
) && !was_frozen
) {
2549 if (kmem_cache_has_cpu_partial(s
) && !prior
) {
2552 * Slab was on no list before and will be
2554 * We can defer the list move and instead
2559 } else { /* Needs to be taken off a list */
2561 n
= get_node(s
, page_to_nid(page
));
2563 * Speculatively acquire the list_lock.
2564 * If the cmpxchg does not succeed then we may
2565 * drop the list_lock without any processing.
2567 * Otherwise the list_lock will synchronize with
2568 * other processors updating the list of slabs.
2570 spin_lock_irqsave(&n
->list_lock
, flags
);
2575 } while (!cmpxchg_double_slab(s
, page
,
2577 object
, new.counters
,
2583 * If we just froze the page then put it onto the
2584 * per cpu partial list.
2586 if (new.frozen
&& !was_frozen
) {
2587 put_cpu_partial(s
, page
, 1);
2588 stat(s
, CPU_PARTIAL_FREE
);
2591 * The list lock was not taken therefore no list
2592 * activity can be necessary.
2595 stat(s
, FREE_FROZEN
);
2599 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
))
2603 * Objects left in the slab. If it was not on the partial list before
2606 if (!kmem_cache_has_cpu_partial(s
) && unlikely(!prior
)) {
2607 if (kmem_cache_debug(s
))
2608 remove_full(s
, n
, page
);
2609 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2610 stat(s
, FREE_ADD_PARTIAL
);
2612 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2618 * Slab on the partial list.
2620 remove_partial(n
, page
);
2621 stat(s
, FREE_REMOVE_PARTIAL
);
2623 /* Slab must be on the full list */
2624 remove_full(s
, n
, page
);
2627 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2629 discard_slab(s
, page
);
2633 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2634 * can perform fastpath freeing without additional function calls.
2636 * The fastpath is only possible if we are freeing to the current cpu slab
2637 * of this processor. This typically the case if we have just allocated
2640 * If fastpath is not possible then fall back to __slab_free where we deal
2641 * with all sorts of special processing.
2643 static __always_inline
void slab_free(struct kmem_cache
*s
,
2644 struct page
*page
, void *x
, unsigned long addr
)
2646 void **object
= (void *)x
;
2647 struct kmem_cache_cpu
*c
;
2650 slab_free_hook(s
, x
);
2654 * Determine the currently cpus per cpu slab.
2655 * The cpu may change afterward. However that does not matter since
2656 * data is retrieved via this pointer. If we are on the same cpu
2657 * during the cmpxchg then the free will succedd.
2660 c
= this_cpu_ptr(s
->cpu_slab
);
2665 if (likely(page
== c
->page
)) {
2666 set_freepointer(s
, object
, c
->freelist
);
2668 if (unlikely(!this_cpu_cmpxchg_double(
2669 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2671 object
, next_tid(tid
)))) {
2673 note_cmpxchg_failure("slab_free", s
, tid
);
2676 stat(s
, FREE_FASTPATH
);
2678 __slab_free(s
, page
, x
, addr
);
2682 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
2684 s
= cache_from_obj(s
, x
);
2687 slab_free(s
, virt_to_head_page(x
), x
, _RET_IP_
);
2688 trace_kmem_cache_free(_RET_IP_
, x
);
2690 EXPORT_SYMBOL(kmem_cache_free
);
2693 * Object placement in a slab is made very easy because we always start at
2694 * offset 0. If we tune the size of the object to the alignment then we can
2695 * get the required alignment by putting one properly sized object after
2698 * Notice that the allocation order determines the sizes of the per cpu
2699 * caches. Each processor has always one slab available for allocations.
2700 * Increasing the allocation order reduces the number of times that slabs
2701 * must be moved on and off the partial lists and is therefore a factor in
2706 * Mininum / Maximum order of slab pages. This influences locking overhead
2707 * and slab fragmentation. A higher order reduces the number of partial slabs
2708 * and increases the number of allocations possible without having to
2709 * take the list_lock.
2711 static int slub_min_order
;
2712 static int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
2713 static int slub_min_objects
;
2716 * Calculate the order of allocation given an slab object size.
2718 * The order of allocation has significant impact on performance and other
2719 * system components. Generally order 0 allocations should be preferred since
2720 * order 0 does not cause fragmentation in the page allocator. Larger objects
2721 * be problematic to put into order 0 slabs because there may be too much
2722 * unused space left. We go to a higher order if more than 1/16th of the slab
2725 * In order to reach satisfactory performance we must ensure that a minimum
2726 * number of objects is in one slab. Otherwise we may generate too much
2727 * activity on the partial lists which requires taking the list_lock. This is
2728 * less a concern for large slabs though which are rarely used.
2730 * slub_max_order specifies the order where we begin to stop considering the
2731 * number of objects in a slab as critical. If we reach slub_max_order then
2732 * we try to keep the page order as low as possible. So we accept more waste
2733 * of space in favor of a small page order.
2735 * Higher order allocations also allow the placement of more objects in a
2736 * slab and thereby reduce object handling overhead. If the user has
2737 * requested a higher mininum order then we start with that one instead of
2738 * the smallest order which will fit the object.
2740 static inline int slab_order(int size
, int min_objects
,
2741 int max_order
, int fract_leftover
, int reserved
)
2745 int min_order
= slub_min_order
;
2747 if (order_objects(min_order
, size
, reserved
) > MAX_OBJS_PER_PAGE
)
2748 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
2750 for (order
= max(min_order
,
2751 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
2752 order
<= max_order
; order
++) {
2754 unsigned long slab_size
= PAGE_SIZE
<< order
;
2756 if (slab_size
< min_objects
* size
+ reserved
)
2759 rem
= (slab_size
- reserved
) % size
;
2761 if (rem
<= slab_size
/ fract_leftover
)
2769 static inline int calculate_order(int size
, int reserved
)
2777 * Attempt to find best configuration for a slab. This
2778 * works by first attempting to generate a layout with
2779 * the best configuration and backing off gradually.
2781 * First we reduce the acceptable waste in a slab. Then
2782 * we reduce the minimum objects required in a slab.
2784 min_objects
= slub_min_objects
;
2786 min_objects
= 4 * (fls(nr_cpu_ids
) + 1);
2787 max_objects
= order_objects(slub_max_order
, size
, reserved
);
2788 min_objects
= min(min_objects
, max_objects
);
2790 while (min_objects
> 1) {
2792 while (fraction
>= 4) {
2793 order
= slab_order(size
, min_objects
,
2794 slub_max_order
, fraction
, reserved
);
2795 if (order
<= slub_max_order
)
2803 * We were unable to place multiple objects in a slab. Now
2804 * lets see if we can place a single object there.
2806 order
= slab_order(size
, 1, slub_max_order
, 1, reserved
);
2807 if (order
<= slub_max_order
)
2811 * Doh this slab cannot be placed using slub_max_order.
2813 order
= slab_order(size
, 1, MAX_ORDER
, 1, reserved
);
2814 if (order
< MAX_ORDER
)
2820 init_kmem_cache_node(struct kmem_cache_node
*n
)
2823 spin_lock_init(&n
->list_lock
);
2824 INIT_LIST_HEAD(&n
->partial
);
2825 #ifdef CONFIG_SLUB_DEBUG
2826 atomic_long_set(&n
->nr_slabs
, 0);
2827 atomic_long_set(&n
->total_objects
, 0);
2828 INIT_LIST_HEAD(&n
->full
);
2832 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
2834 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
2835 KMALLOC_SHIFT_HIGH
* sizeof(struct kmem_cache_cpu
));
2838 * Must align to double word boundary for the double cmpxchg
2839 * instructions to work; see __pcpu_double_call_return_bool().
2841 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
2842 2 * sizeof(void *));
2847 init_kmem_cache_cpus(s
);
2852 static struct kmem_cache
*kmem_cache_node
;
2855 * No kmalloc_node yet so do it by hand. We know that this is the first
2856 * slab on the node for this slabcache. There are no concurrent accesses
2859 * Note that this function only works on the kmem_cache_node
2860 * when allocating for the kmem_cache_node. This is used for bootstrapping
2861 * memory on a fresh node that has no slab structures yet.
2863 static void early_kmem_cache_node_alloc(int node
)
2866 struct kmem_cache_node
*n
;
2868 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
2870 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
2873 if (page_to_nid(page
) != node
) {
2874 pr_err("SLUB: Unable to allocate memory from node %d\n", node
);
2875 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
2880 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
2883 kmem_cache_node
->node
[node
] = n
;
2884 #ifdef CONFIG_SLUB_DEBUG
2885 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
2886 init_tracking(kmem_cache_node
, n
);
2888 init_kmem_cache_node(n
);
2889 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
2892 * No locks need to be taken here as it has just been
2893 * initialized and there is no concurrent access.
2895 __add_partial(n
, page
, DEACTIVATE_TO_HEAD
);
2898 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2901 struct kmem_cache_node
*n
;
2903 for_each_kmem_cache_node(s
, node
, n
) {
2904 kmem_cache_free(kmem_cache_node
, n
);
2905 s
->node
[node
] = NULL
;
2909 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
2913 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2914 struct kmem_cache_node
*n
;
2916 if (slab_state
== DOWN
) {
2917 early_kmem_cache_node_alloc(node
);
2920 n
= kmem_cache_alloc_node(kmem_cache_node
,
2924 free_kmem_cache_nodes(s
);
2929 init_kmem_cache_node(n
);
2934 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
2936 if (min
< MIN_PARTIAL
)
2938 else if (min
> MAX_PARTIAL
)
2940 s
->min_partial
= min
;
2944 * calculate_sizes() determines the order and the distribution of data within
2947 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
2949 unsigned long flags
= s
->flags
;
2950 unsigned long size
= s
->object_size
;
2954 * Round up object size to the next word boundary. We can only
2955 * place the free pointer at word boundaries and this determines
2956 * the possible location of the free pointer.
2958 size
= ALIGN(size
, sizeof(void *));
2960 #ifdef CONFIG_SLUB_DEBUG
2962 * Determine if we can poison the object itself. If the user of
2963 * the slab may touch the object after free or before allocation
2964 * then we should never poison the object itself.
2966 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
2968 s
->flags
|= __OBJECT_POISON
;
2970 s
->flags
&= ~__OBJECT_POISON
;
2974 * If we are Redzoning then check if there is some space between the
2975 * end of the object and the free pointer. If not then add an
2976 * additional word to have some bytes to store Redzone information.
2978 if ((flags
& SLAB_RED_ZONE
) && size
== s
->object_size
)
2979 size
+= sizeof(void *);
2983 * With that we have determined the number of bytes in actual use
2984 * by the object. This is the potential offset to the free pointer.
2988 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
2991 * Relocate free pointer after the object if it is not
2992 * permitted to overwrite the first word of the object on
2995 * This is the case if we do RCU, have a constructor or
2996 * destructor or are poisoning the objects.
2999 size
+= sizeof(void *);
3002 #ifdef CONFIG_SLUB_DEBUG
3003 if (flags
& SLAB_STORE_USER
)
3005 * Need to store information about allocs and frees after
3008 size
+= 2 * sizeof(struct track
);
3010 if (flags
& SLAB_RED_ZONE
)
3012 * Add some empty padding so that we can catch
3013 * overwrites from earlier objects rather than let
3014 * tracking information or the free pointer be
3015 * corrupted if a user writes before the start
3018 size
+= sizeof(void *);
3022 * SLUB stores one object immediately after another beginning from
3023 * offset 0. In order to align the objects we have to simply size
3024 * each object to conform to the alignment.
3026 size
= ALIGN(size
, s
->align
);
3028 if (forced_order
>= 0)
3029 order
= forced_order
;
3031 order
= calculate_order(size
, s
->reserved
);
3038 s
->allocflags
|= __GFP_COMP
;
3040 if (s
->flags
& SLAB_CACHE_DMA
)
3041 s
->allocflags
|= GFP_DMA
;
3043 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3044 s
->allocflags
|= __GFP_RECLAIMABLE
;
3047 * Determine the number of objects per slab
3049 s
->oo
= oo_make(order
, size
, s
->reserved
);
3050 s
->min
= oo_make(get_order(size
), size
, s
->reserved
);
3051 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
3054 return !!oo_objects(s
->oo
);
3057 static int kmem_cache_open(struct kmem_cache
*s
, unsigned long flags
)
3059 s
->flags
= kmem_cache_flags(s
->size
, flags
, s
->name
, s
->ctor
);
3062 if (need_reserve_slab_rcu
&& (s
->flags
& SLAB_DESTROY_BY_RCU
))
3063 s
->reserved
= sizeof(struct rcu_head
);
3065 if (!calculate_sizes(s
, -1))
3067 if (disable_higher_order_debug
) {
3069 * Disable debugging flags that store metadata if the min slab
3072 if (get_order(s
->size
) > get_order(s
->object_size
)) {
3073 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
3075 if (!calculate_sizes(s
, -1))
3080 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3081 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3082 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_DEBUG_FLAGS
) == 0)
3083 /* Enable fast mode */
3084 s
->flags
|= __CMPXCHG_DOUBLE
;
3088 * The larger the object size is, the more pages we want on the partial
3089 * list to avoid pounding the page allocator excessively.
3091 set_min_partial(s
, ilog2(s
->size
) / 2);
3094 * cpu_partial determined the maximum number of objects kept in the
3095 * per cpu partial lists of a processor.
3097 * Per cpu partial lists mainly contain slabs that just have one
3098 * object freed. If they are used for allocation then they can be
3099 * filled up again with minimal effort. The slab will never hit the
3100 * per node partial lists and therefore no locking will be required.
3102 * This setting also determines
3104 * A) The number of objects from per cpu partial slabs dumped to the
3105 * per node list when we reach the limit.
3106 * B) The number of objects in cpu partial slabs to extract from the
3107 * per node list when we run out of per cpu objects. We only fetch
3108 * 50% to keep some capacity around for frees.
3110 if (!kmem_cache_has_cpu_partial(s
))
3112 else if (s
->size
>= PAGE_SIZE
)
3114 else if (s
->size
>= 1024)
3116 else if (s
->size
>= 256)
3117 s
->cpu_partial
= 13;
3119 s
->cpu_partial
= 30;
3122 s
->remote_node_defrag_ratio
= 1000;
3124 if (!init_kmem_cache_nodes(s
))
3127 if (alloc_kmem_cache_cpus(s
))
3130 free_kmem_cache_nodes(s
);
3132 if (flags
& SLAB_PANIC
)
3133 panic("Cannot create slab %s size=%lu realsize=%u "
3134 "order=%u offset=%u flags=%lx\n",
3135 s
->name
, (unsigned long)s
->size
, s
->size
,
3136 oo_order(s
->oo
), s
->offset
, flags
);
3140 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
3143 #ifdef CONFIG_SLUB_DEBUG
3144 void *addr
= page_address(page
);
3146 unsigned long *map
= kzalloc(BITS_TO_LONGS(page
->objects
) *
3147 sizeof(long), GFP_ATOMIC
);
3150 slab_err(s
, page
, text
, s
->name
);
3153 get_map(s
, page
, map
);
3154 for_each_object(p
, s
, addr
, page
->objects
) {
3156 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
3157 pr_err("INFO: Object 0x%p @offset=%tu\n", p
, p
- addr
);
3158 print_tracking(s
, p
);
3167 * Attempt to free all partial slabs on a node.
3168 * This is called from kmem_cache_close(). We must be the last thread
3169 * using the cache and therefore we do not need to lock anymore.
3171 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
3173 struct page
*page
, *h
;
3175 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
3177 __remove_partial(n
, page
);
3178 discard_slab(s
, page
);
3180 list_slab_objects(s
, page
,
3181 "Objects remaining in %s on kmem_cache_close()");
3187 * Release all resources used by a slab cache.
3189 static inline int kmem_cache_close(struct kmem_cache
*s
)
3192 struct kmem_cache_node
*n
;
3195 /* Attempt to free all objects */
3196 for_each_kmem_cache_node(s
, node
, n
) {
3198 if (n
->nr_partial
|| slabs_node(s
, node
))
3201 free_percpu(s
->cpu_slab
);
3202 free_kmem_cache_nodes(s
);
3206 int __kmem_cache_shutdown(struct kmem_cache
*s
)
3208 return kmem_cache_close(s
);
3211 /********************************************************************
3213 *******************************************************************/
3215 static int __init
setup_slub_min_order(char *str
)
3217 get_option(&str
, &slub_min_order
);
3222 __setup("slub_min_order=", setup_slub_min_order
);
3224 static int __init
setup_slub_max_order(char *str
)
3226 get_option(&str
, &slub_max_order
);
3227 slub_max_order
= min(slub_max_order
, MAX_ORDER
- 1);
3232 __setup("slub_max_order=", setup_slub_max_order
);
3234 static int __init
setup_slub_min_objects(char *str
)
3236 get_option(&str
, &slub_min_objects
);
3241 __setup("slub_min_objects=", setup_slub_min_objects
);
3243 void *__kmalloc(size_t size
, gfp_t flags
)
3245 struct kmem_cache
*s
;
3248 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3249 return kmalloc_large(size
, flags
);
3251 s
= kmalloc_slab(size
, flags
);
3253 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3256 ret
= slab_alloc(s
, flags
, _RET_IP_
);
3258 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
3262 EXPORT_SYMBOL(__kmalloc
);
3265 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
3270 flags
|= __GFP_COMP
| __GFP_NOTRACK
;
3271 page
= alloc_kmem_pages_node(node
, flags
, get_order(size
));
3273 ptr
= page_address(page
);
3275 kmalloc_large_node_hook(ptr
, size
, flags
);
3279 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3281 struct kmem_cache
*s
;
3284 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3285 ret
= kmalloc_large_node(size
, flags
, node
);
3287 trace_kmalloc_node(_RET_IP_
, ret
,
3288 size
, PAGE_SIZE
<< get_order(size
),
3294 s
= kmalloc_slab(size
, flags
);
3296 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3299 ret
= slab_alloc_node(s
, flags
, node
, _RET_IP_
);
3301 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
3305 EXPORT_SYMBOL(__kmalloc_node
);
3308 size_t ksize(const void *object
)
3312 if (unlikely(object
== ZERO_SIZE_PTR
))
3315 page
= virt_to_head_page(object
);
3317 if (unlikely(!PageSlab(page
))) {
3318 WARN_ON(!PageCompound(page
));
3319 return PAGE_SIZE
<< compound_order(page
);
3322 return slab_ksize(page
->slab_cache
);
3324 EXPORT_SYMBOL(ksize
);
3326 void kfree(const void *x
)
3329 void *object
= (void *)x
;
3331 trace_kfree(_RET_IP_
, x
);
3333 if (unlikely(ZERO_OR_NULL_PTR(x
)))
3336 page
= virt_to_head_page(x
);
3337 if (unlikely(!PageSlab(page
))) {
3338 BUG_ON(!PageCompound(page
));
3340 __free_kmem_pages(page
, compound_order(page
));
3343 slab_free(page
->slab_cache
, page
, object
, _RET_IP_
);
3345 EXPORT_SYMBOL(kfree
);
3348 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3349 * the remaining slabs by the number of items in use. The slabs with the
3350 * most items in use come first. New allocations will then fill those up
3351 * and thus they can be removed from the partial lists.
3353 * The slabs with the least items are placed last. This results in them
3354 * being allocated from last increasing the chance that the last objects
3355 * are freed in them.
3357 int __kmem_cache_shrink(struct kmem_cache
*s
)
3361 struct kmem_cache_node
*n
;
3364 int objects
= oo_objects(s
->max
);
3365 struct list_head
*slabs_by_inuse
=
3366 kmalloc(sizeof(struct list_head
) * objects
, GFP_KERNEL
);
3367 unsigned long flags
;
3369 if (!slabs_by_inuse
)
3373 for_each_kmem_cache_node(s
, node
, n
) {
3377 for (i
= 0; i
< objects
; i
++)
3378 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
3380 spin_lock_irqsave(&n
->list_lock
, flags
);
3383 * Build lists indexed by the items in use in each slab.
3385 * Note that concurrent frees may occur while we hold the
3386 * list_lock. page->inuse here is the upper limit.
3388 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
3389 list_move(&page
->lru
, slabs_by_inuse
+ page
->inuse
);
3395 * Rebuild the partial list with the slabs filled up most
3396 * first and the least used slabs at the end.
3398 for (i
= objects
- 1; i
> 0; i
--)
3399 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
3401 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3403 /* Release empty slabs */
3404 list_for_each_entry_safe(page
, t
, slabs_by_inuse
, lru
)
3405 discard_slab(s
, page
);
3408 kfree(slabs_by_inuse
);
3412 static int slab_mem_going_offline_callback(void *arg
)
3414 struct kmem_cache
*s
;
3416 mutex_lock(&slab_mutex
);
3417 list_for_each_entry(s
, &slab_caches
, list
)
3418 __kmem_cache_shrink(s
);
3419 mutex_unlock(&slab_mutex
);
3424 static void slab_mem_offline_callback(void *arg
)
3426 struct kmem_cache_node
*n
;
3427 struct kmem_cache
*s
;
3428 struct memory_notify
*marg
= arg
;
3431 offline_node
= marg
->status_change_nid_normal
;
3434 * If the node still has available memory. we need kmem_cache_node
3437 if (offline_node
< 0)
3440 mutex_lock(&slab_mutex
);
3441 list_for_each_entry(s
, &slab_caches
, list
) {
3442 n
= get_node(s
, offline_node
);
3445 * if n->nr_slabs > 0, slabs still exist on the node
3446 * that is going down. We were unable to free them,
3447 * and offline_pages() function shouldn't call this
3448 * callback. So, we must fail.
3450 BUG_ON(slabs_node(s
, offline_node
));
3452 s
->node
[offline_node
] = NULL
;
3453 kmem_cache_free(kmem_cache_node
, n
);
3456 mutex_unlock(&slab_mutex
);
3459 static int slab_mem_going_online_callback(void *arg
)
3461 struct kmem_cache_node
*n
;
3462 struct kmem_cache
*s
;
3463 struct memory_notify
*marg
= arg
;
3464 int nid
= marg
->status_change_nid_normal
;
3468 * If the node's memory is already available, then kmem_cache_node is
3469 * already created. Nothing to do.
3475 * We are bringing a node online. No memory is available yet. We must
3476 * allocate a kmem_cache_node structure in order to bring the node
3479 mutex_lock(&slab_mutex
);
3480 list_for_each_entry(s
, &slab_caches
, list
) {
3482 * XXX: kmem_cache_alloc_node will fallback to other nodes
3483 * since memory is not yet available from the node that
3486 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
3491 init_kmem_cache_node(n
);
3495 mutex_unlock(&slab_mutex
);
3499 static int slab_memory_callback(struct notifier_block
*self
,
3500 unsigned long action
, void *arg
)
3505 case MEM_GOING_ONLINE
:
3506 ret
= slab_mem_going_online_callback(arg
);
3508 case MEM_GOING_OFFLINE
:
3509 ret
= slab_mem_going_offline_callback(arg
);
3512 case MEM_CANCEL_ONLINE
:
3513 slab_mem_offline_callback(arg
);
3516 case MEM_CANCEL_OFFLINE
:
3520 ret
= notifier_from_errno(ret
);
3526 static struct notifier_block slab_memory_callback_nb
= {
3527 .notifier_call
= slab_memory_callback
,
3528 .priority
= SLAB_CALLBACK_PRI
,
3531 /********************************************************************
3532 * Basic setup of slabs
3533 *******************************************************************/
3536 * Used for early kmem_cache structures that were allocated using
3537 * the page allocator. Allocate them properly then fix up the pointers
3538 * that may be pointing to the wrong kmem_cache structure.
3541 static struct kmem_cache
* __init
bootstrap(struct kmem_cache
*static_cache
)
3544 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
3545 struct kmem_cache_node
*n
;
3547 memcpy(s
, static_cache
, kmem_cache
->object_size
);
3550 * This runs very early, and only the boot processor is supposed to be
3551 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3554 __flush_cpu_slab(s
, smp_processor_id());
3555 for_each_kmem_cache_node(s
, node
, n
) {
3558 list_for_each_entry(p
, &n
->partial
, lru
)
3561 #ifdef CONFIG_SLUB_DEBUG
3562 list_for_each_entry(p
, &n
->full
, lru
)
3566 list_add(&s
->list
, &slab_caches
);
3570 void __init
kmem_cache_init(void)
3572 static __initdata
struct kmem_cache boot_kmem_cache
,
3573 boot_kmem_cache_node
;
3575 if (debug_guardpage_minorder())
3578 kmem_cache_node
= &boot_kmem_cache_node
;
3579 kmem_cache
= &boot_kmem_cache
;
3581 create_boot_cache(kmem_cache_node
, "kmem_cache_node",
3582 sizeof(struct kmem_cache_node
), SLAB_HWCACHE_ALIGN
);
3584 register_hotmemory_notifier(&slab_memory_callback_nb
);
3586 /* Able to allocate the per node structures */
3587 slab_state
= PARTIAL
;
3589 create_boot_cache(kmem_cache
, "kmem_cache",
3590 offsetof(struct kmem_cache
, node
) +
3591 nr_node_ids
* sizeof(struct kmem_cache_node
*),
3592 SLAB_HWCACHE_ALIGN
);
3594 kmem_cache
= bootstrap(&boot_kmem_cache
);
3597 * Allocate kmem_cache_node properly from the kmem_cache slab.
3598 * kmem_cache_node is separately allocated so no need to
3599 * update any list pointers.
3601 kmem_cache_node
= bootstrap(&boot_kmem_cache_node
);
3603 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3604 create_kmalloc_caches(0);
3607 register_cpu_notifier(&slab_notifier
);
3610 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
3612 slub_min_order
, slub_max_order
, slub_min_objects
,
3613 nr_cpu_ids
, nr_node_ids
);
3616 void __init
kmem_cache_init_late(void)
3621 __kmem_cache_alias(const char *name
, size_t size
, size_t align
,
3622 unsigned long flags
, void (*ctor
)(void *))
3624 struct kmem_cache
*s
;
3626 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3629 struct kmem_cache
*c
;
3634 * Adjust the object sizes so that we clear
3635 * the complete object on kzalloc.
3637 s
->object_size
= max(s
->object_size
, (int)size
);
3638 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3640 for_each_memcg_cache_index(i
) {
3641 c
= cache_from_memcg_idx(s
, i
);
3644 c
->object_size
= s
->object_size
;
3645 c
->inuse
= max_t(int, c
->inuse
,
3646 ALIGN(size
, sizeof(void *)));
3649 if (sysfs_slab_alias(s
, name
)) {
3658 int __kmem_cache_create(struct kmem_cache
*s
, unsigned long flags
)
3662 err
= kmem_cache_open(s
, flags
);
3666 /* Mutex is not taken during early boot */
3667 if (slab_state
<= UP
)
3670 memcg_propagate_slab_attrs(s
);
3671 err
= sysfs_slab_add(s
);
3673 kmem_cache_close(s
);
3680 * Use the cpu notifier to insure that the cpu slabs are flushed when
3683 static int slab_cpuup_callback(struct notifier_block
*nfb
,
3684 unsigned long action
, void *hcpu
)
3686 long cpu
= (long)hcpu
;
3687 struct kmem_cache
*s
;
3688 unsigned long flags
;
3691 case CPU_UP_CANCELED
:
3692 case CPU_UP_CANCELED_FROZEN
:
3694 case CPU_DEAD_FROZEN
:
3695 mutex_lock(&slab_mutex
);
3696 list_for_each_entry(s
, &slab_caches
, list
) {
3697 local_irq_save(flags
);
3698 __flush_cpu_slab(s
, cpu
);
3699 local_irq_restore(flags
);
3701 mutex_unlock(&slab_mutex
);
3709 static struct notifier_block slab_notifier
= {
3710 .notifier_call
= slab_cpuup_callback
3715 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
3717 struct kmem_cache
*s
;
3720 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3721 return kmalloc_large(size
, gfpflags
);
3723 s
= kmalloc_slab(size
, gfpflags
);
3725 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3728 ret
= slab_alloc(s
, gfpflags
, caller
);
3730 /* Honor the call site pointer we received. */
3731 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
3737 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3738 int node
, unsigned long caller
)
3740 struct kmem_cache
*s
;
3743 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3744 ret
= kmalloc_large_node(size
, gfpflags
, node
);
3746 trace_kmalloc_node(caller
, ret
,
3747 size
, PAGE_SIZE
<< get_order(size
),
3753 s
= kmalloc_slab(size
, gfpflags
);
3755 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3758 ret
= slab_alloc_node(s
, gfpflags
, node
, caller
);
3760 /* Honor the call site pointer we received. */
3761 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
3768 static int count_inuse(struct page
*page
)
3773 static int count_total(struct page
*page
)
3775 return page
->objects
;
3779 #ifdef CONFIG_SLUB_DEBUG
3780 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3784 void *addr
= page_address(page
);
3786 if (!check_slab(s
, page
) ||
3787 !on_freelist(s
, page
, NULL
))
3790 /* Now we know that a valid freelist exists */
3791 bitmap_zero(map
, page
->objects
);
3793 get_map(s
, page
, map
);
3794 for_each_object(p
, s
, addr
, page
->objects
) {
3795 if (test_bit(slab_index(p
, s
, addr
), map
))
3796 if (!check_object(s
, page
, p
, SLUB_RED_INACTIVE
))
3800 for_each_object(p
, s
, addr
, page
->objects
)
3801 if (!test_bit(slab_index(p
, s
, addr
), map
))
3802 if (!check_object(s
, page
, p
, SLUB_RED_ACTIVE
))
3807 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
3811 validate_slab(s
, page
, map
);
3815 static int validate_slab_node(struct kmem_cache
*s
,
3816 struct kmem_cache_node
*n
, unsigned long *map
)
3818 unsigned long count
= 0;
3820 unsigned long flags
;
3822 spin_lock_irqsave(&n
->list_lock
, flags
);
3824 list_for_each_entry(page
, &n
->partial
, lru
) {
3825 validate_slab_slab(s
, page
, map
);
3828 if (count
!= n
->nr_partial
)
3829 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
3830 s
->name
, count
, n
->nr_partial
);
3832 if (!(s
->flags
& SLAB_STORE_USER
))
3835 list_for_each_entry(page
, &n
->full
, lru
) {
3836 validate_slab_slab(s
, page
, map
);
3839 if (count
!= atomic_long_read(&n
->nr_slabs
))
3840 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
3841 s
->name
, count
, atomic_long_read(&n
->nr_slabs
));
3844 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3848 static long validate_slab_cache(struct kmem_cache
*s
)
3851 unsigned long count
= 0;
3852 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
3853 sizeof(unsigned long), GFP_KERNEL
);
3854 struct kmem_cache_node
*n
;
3860 for_each_kmem_cache_node(s
, node
, n
)
3861 count
+= validate_slab_node(s
, n
, map
);
3866 * Generate lists of code addresses where slabcache objects are allocated
3871 unsigned long count
;
3878 DECLARE_BITMAP(cpus
, NR_CPUS
);
3884 unsigned long count
;
3885 struct location
*loc
;
3888 static void free_loc_track(struct loc_track
*t
)
3891 free_pages((unsigned long)t
->loc
,
3892 get_order(sizeof(struct location
) * t
->max
));
3895 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
3900 order
= get_order(sizeof(struct location
) * max
);
3902 l
= (void *)__get_free_pages(flags
, order
);
3907 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
3915 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
3916 const struct track
*track
)
3918 long start
, end
, pos
;
3920 unsigned long caddr
;
3921 unsigned long age
= jiffies
- track
->when
;
3927 pos
= start
+ (end
- start
+ 1) / 2;
3930 * There is nothing at "end". If we end up there
3931 * we need to add something to before end.
3936 caddr
= t
->loc
[pos
].addr
;
3937 if (track
->addr
== caddr
) {
3943 if (age
< l
->min_time
)
3945 if (age
> l
->max_time
)
3948 if (track
->pid
< l
->min_pid
)
3949 l
->min_pid
= track
->pid
;
3950 if (track
->pid
> l
->max_pid
)
3951 l
->max_pid
= track
->pid
;
3953 cpumask_set_cpu(track
->cpu
,
3954 to_cpumask(l
->cpus
));
3956 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3960 if (track
->addr
< caddr
)
3967 * Not found. Insert new tracking element.
3969 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
3975 (t
->count
- pos
) * sizeof(struct location
));
3978 l
->addr
= track
->addr
;
3982 l
->min_pid
= track
->pid
;
3983 l
->max_pid
= track
->pid
;
3984 cpumask_clear(to_cpumask(l
->cpus
));
3985 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
3986 nodes_clear(l
->nodes
);
3987 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3991 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
3992 struct page
*page
, enum track_item alloc
,
3995 void *addr
= page_address(page
);
3998 bitmap_zero(map
, page
->objects
);
3999 get_map(s
, page
, map
);
4001 for_each_object(p
, s
, addr
, page
->objects
)
4002 if (!test_bit(slab_index(p
, s
, addr
), map
))
4003 add_location(t
, s
, get_track(s
, p
, alloc
));
4006 static int list_locations(struct kmem_cache
*s
, char *buf
,
4007 enum track_item alloc
)
4011 struct loc_track t
= { 0, 0, NULL
};
4013 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4014 sizeof(unsigned long), GFP_KERNEL
);
4015 struct kmem_cache_node
*n
;
4017 if (!map
|| !alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
4020 return sprintf(buf
, "Out of memory\n");
4022 /* Push back cpu slabs */
4025 for_each_kmem_cache_node(s
, node
, n
) {
4026 unsigned long flags
;
4029 if (!atomic_long_read(&n
->nr_slabs
))
4032 spin_lock_irqsave(&n
->list_lock
, flags
);
4033 list_for_each_entry(page
, &n
->partial
, lru
)
4034 process_slab(&t
, s
, page
, alloc
, map
);
4035 list_for_each_entry(page
, &n
->full
, lru
)
4036 process_slab(&t
, s
, page
, alloc
, map
);
4037 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4040 for (i
= 0; i
< t
.count
; i
++) {
4041 struct location
*l
= &t
.loc
[i
];
4043 if (len
> PAGE_SIZE
- KSYM_SYMBOL_LEN
- 100)
4045 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
4048 len
+= sprintf(buf
+ len
, "%pS", (void *)l
->addr
);
4050 len
+= sprintf(buf
+ len
, "<not-available>");
4052 if (l
->sum_time
!= l
->min_time
) {
4053 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
4055 (long)div_u64(l
->sum_time
, l
->count
),
4058 len
+= sprintf(buf
+ len
, " age=%ld",
4061 if (l
->min_pid
!= l
->max_pid
)
4062 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
4063 l
->min_pid
, l
->max_pid
);
4065 len
+= sprintf(buf
+ len
, " pid=%ld",
4068 if (num_online_cpus() > 1 &&
4069 !cpumask_empty(to_cpumask(l
->cpus
)) &&
4070 len
< PAGE_SIZE
- 60) {
4071 len
+= sprintf(buf
+ len
, " cpus=");
4072 len
+= cpulist_scnprintf(buf
+ len
,
4073 PAGE_SIZE
- len
- 50,
4074 to_cpumask(l
->cpus
));
4077 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
) &&
4078 len
< PAGE_SIZE
- 60) {
4079 len
+= sprintf(buf
+ len
, " nodes=");
4080 len
+= nodelist_scnprintf(buf
+ len
,
4081 PAGE_SIZE
- len
- 50,
4085 len
+= sprintf(buf
+ len
, "\n");
4091 len
+= sprintf(buf
, "No data\n");
4096 #ifdef SLUB_RESILIENCY_TEST
4097 static void __init
resiliency_test(void)
4101 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 16 || KMALLOC_SHIFT_HIGH
< 10);
4103 pr_err("SLUB resiliency testing\n");
4104 pr_err("-----------------------\n");
4105 pr_err("A. Corruption after allocation\n");
4107 p
= kzalloc(16, GFP_KERNEL
);
4109 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4112 validate_slab_cache(kmalloc_caches
[4]);
4114 /* Hmmm... The next two are dangerous */
4115 p
= kzalloc(32, GFP_KERNEL
);
4116 p
[32 + sizeof(void *)] = 0x34;
4117 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4119 pr_err("If allocated object is overwritten then not detectable\n\n");
4121 validate_slab_cache(kmalloc_caches
[5]);
4122 p
= kzalloc(64, GFP_KERNEL
);
4123 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
4125 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4127 pr_err("If allocated object is overwritten then not detectable\n\n");
4128 validate_slab_cache(kmalloc_caches
[6]);
4130 pr_err("\nB. Corruption after free\n");
4131 p
= kzalloc(128, GFP_KERNEL
);
4134 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
4135 validate_slab_cache(kmalloc_caches
[7]);
4137 p
= kzalloc(256, GFP_KERNEL
);
4140 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
4141 validate_slab_cache(kmalloc_caches
[8]);
4143 p
= kzalloc(512, GFP_KERNEL
);
4146 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
4147 validate_slab_cache(kmalloc_caches
[9]);
4151 static void resiliency_test(void) {};
4156 enum slab_stat_type
{
4157 SL_ALL
, /* All slabs */
4158 SL_PARTIAL
, /* Only partially allocated slabs */
4159 SL_CPU
, /* Only slabs used for cpu caches */
4160 SL_OBJECTS
, /* Determine allocated objects not slabs */
4161 SL_TOTAL
/* Determine object capacity not slabs */
4164 #define SO_ALL (1 << SL_ALL)
4165 #define SO_PARTIAL (1 << SL_PARTIAL)
4166 #define SO_CPU (1 << SL_CPU)
4167 #define SO_OBJECTS (1 << SL_OBJECTS)
4168 #define SO_TOTAL (1 << SL_TOTAL)
4170 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
4171 char *buf
, unsigned long flags
)
4173 unsigned long total
= 0;
4176 unsigned long *nodes
;
4178 nodes
= kzalloc(sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
4182 if (flags
& SO_CPU
) {
4185 for_each_possible_cpu(cpu
) {
4186 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
,
4191 page
= ACCESS_ONCE(c
->page
);
4195 node
= page_to_nid(page
);
4196 if (flags
& SO_TOTAL
)
4198 else if (flags
& SO_OBJECTS
)
4206 page
= ACCESS_ONCE(c
->partial
);
4208 node
= page_to_nid(page
);
4209 if (flags
& SO_TOTAL
)
4211 else if (flags
& SO_OBJECTS
)
4222 #ifdef CONFIG_SLUB_DEBUG
4223 if (flags
& SO_ALL
) {
4224 struct kmem_cache_node
*n
;
4226 for_each_kmem_cache_node(s
, node
, n
) {
4228 if (flags
& SO_TOTAL
)
4229 x
= atomic_long_read(&n
->total_objects
);
4230 else if (flags
& SO_OBJECTS
)
4231 x
= atomic_long_read(&n
->total_objects
) -
4232 count_partial(n
, count_free
);
4234 x
= atomic_long_read(&n
->nr_slabs
);
4241 if (flags
& SO_PARTIAL
) {
4242 struct kmem_cache_node
*n
;
4244 for_each_kmem_cache_node(s
, node
, n
) {
4245 if (flags
& SO_TOTAL
)
4246 x
= count_partial(n
, count_total
);
4247 else if (flags
& SO_OBJECTS
)
4248 x
= count_partial(n
, count_inuse
);
4255 x
= sprintf(buf
, "%lu", total
);
4257 for (node
= 0; node
< nr_node_ids
; node
++)
4259 x
+= sprintf(buf
+ x
, " N%d=%lu",
4264 return x
+ sprintf(buf
+ x
, "\n");
4267 #ifdef CONFIG_SLUB_DEBUG
4268 static int any_slab_objects(struct kmem_cache
*s
)
4271 struct kmem_cache_node
*n
;
4273 for_each_kmem_cache_node(s
, node
, n
)
4274 if (atomic_long_read(&n
->total_objects
))
4281 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4282 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4284 struct slab_attribute
{
4285 struct attribute attr
;
4286 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
4287 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
4290 #define SLAB_ATTR_RO(_name) \
4291 static struct slab_attribute _name##_attr = \
4292 __ATTR(_name, 0400, _name##_show, NULL)
4294 #define SLAB_ATTR(_name) \
4295 static struct slab_attribute _name##_attr = \
4296 __ATTR(_name, 0600, _name##_show, _name##_store)
4298 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
4300 return sprintf(buf
, "%d\n", s
->size
);
4302 SLAB_ATTR_RO(slab_size
);
4304 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
4306 return sprintf(buf
, "%d\n", s
->align
);
4308 SLAB_ATTR_RO(align
);
4310 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
4312 return sprintf(buf
, "%d\n", s
->object_size
);
4314 SLAB_ATTR_RO(object_size
);
4316 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
4318 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
4320 SLAB_ATTR_RO(objs_per_slab
);
4322 static ssize_t
order_store(struct kmem_cache
*s
,
4323 const char *buf
, size_t length
)
4325 unsigned long order
;
4328 err
= kstrtoul(buf
, 10, &order
);
4332 if (order
> slub_max_order
|| order
< slub_min_order
)
4335 calculate_sizes(s
, order
);
4339 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
4341 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
4345 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
4347 return sprintf(buf
, "%lu\n", s
->min_partial
);
4350 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
4356 err
= kstrtoul(buf
, 10, &min
);
4360 set_min_partial(s
, min
);
4363 SLAB_ATTR(min_partial
);
4365 static ssize_t
cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4367 return sprintf(buf
, "%u\n", s
->cpu_partial
);
4370 static ssize_t
cpu_partial_store(struct kmem_cache
*s
, const char *buf
,
4373 unsigned long objects
;
4376 err
= kstrtoul(buf
, 10, &objects
);
4379 if (objects
&& !kmem_cache_has_cpu_partial(s
))
4382 s
->cpu_partial
= objects
;
4386 SLAB_ATTR(cpu_partial
);
4388 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
4392 return sprintf(buf
, "%pS\n", s
->ctor
);
4396 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
4398 return sprintf(buf
, "%d\n", s
->refcount
< 0 ? 0 : s
->refcount
- 1);
4400 SLAB_ATTR_RO(aliases
);
4402 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
4404 return show_slab_objects(s
, buf
, SO_PARTIAL
);
4406 SLAB_ATTR_RO(partial
);
4408 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
4410 return show_slab_objects(s
, buf
, SO_CPU
);
4412 SLAB_ATTR_RO(cpu_slabs
);
4414 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
4416 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
4418 SLAB_ATTR_RO(objects
);
4420 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
4422 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
4424 SLAB_ATTR_RO(objects_partial
);
4426 static ssize_t
slabs_cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4433 for_each_online_cpu(cpu
) {
4434 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
)->partial
;
4437 pages
+= page
->pages
;
4438 objects
+= page
->pobjects
;
4442 len
= sprintf(buf
, "%d(%d)", objects
, pages
);
4445 for_each_online_cpu(cpu
) {
4446 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
) ->partial
;
4448 if (page
&& len
< PAGE_SIZE
- 20)
4449 len
+= sprintf(buf
+ len
, " C%d=%d(%d)", cpu
,
4450 page
->pobjects
, page
->pages
);
4453 return len
+ sprintf(buf
+ len
, "\n");
4455 SLAB_ATTR_RO(slabs_cpu_partial
);
4457 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
4459 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
4462 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
4463 const char *buf
, size_t length
)
4465 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
4467 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
4470 SLAB_ATTR(reclaim_account
);
4472 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
4474 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
4476 SLAB_ATTR_RO(hwcache_align
);
4478 #ifdef CONFIG_ZONE_DMA
4479 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
4481 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
4483 SLAB_ATTR_RO(cache_dma
);
4486 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
4488 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
4490 SLAB_ATTR_RO(destroy_by_rcu
);
4492 static ssize_t
reserved_show(struct kmem_cache
*s
, char *buf
)
4494 return sprintf(buf
, "%d\n", s
->reserved
);
4496 SLAB_ATTR_RO(reserved
);
4498 #ifdef CONFIG_SLUB_DEBUG
4499 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
4501 return show_slab_objects(s
, buf
, SO_ALL
);
4503 SLAB_ATTR_RO(slabs
);
4505 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
4507 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
4509 SLAB_ATTR_RO(total_objects
);
4511 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
4513 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
4516 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
4517 const char *buf
, size_t length
)
4519 s
->flags
&= ~SLAB_DEBUG_FREE
;
4520 if (buf
[0] == '1') {
4521 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4522 s
->flags
|= SLAB_DEBUG_FREE
;
4526 SLAB_ATTR(sanity_checks
);
4528 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
4530 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
4533 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
4537 * Tracing a merged cache is going to give confusing results
4538 * as well as cause other issues like converting a mergeable
4539 * cache into an umergeable one.
4541 if (s
->refcount
> 1)
4544 s
->flags
&= ~SLAB_TRACE
;
4545 if (buf
[0] == '1') {
4546 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4547 s
->flags
|= SLAB_TRACE
;
4553 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
4555 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
4558 static ssize_t
red_zone_store(struct kmem_cache
*s
,
4559 const char *buf
, size_t length
)
4561 if (any_slab_objects(s
))
4564 s
->flags
&= ~SLAB_RED_ZONE
;
4565 if (buf
[0] == '1') {
4566 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4567 s
->flags
|= SLAB_RED_ZONE
;
4569 calculate_sizes(s
, -1);
4572 SLAB_ATTR(red_zone
);
4574 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
4576 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
4579 static ssize_t
poison_store(struct kmem_cache
*s
,
4580 const char *buf
, size_t length
)
4582 if (any_slab_objects(s
))
4585 s
->flags
&= ~SLAB_POISON
;
4586 if (buf
[0] == '1') {
4587 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4588 s
->flags
|= SLAB_POISON
;
4590 calculate_sizes(s
, -1);
4595 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
4597 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
4600 static ssize_t
store_user_store(struct kmem_cache
*s
,
4601 const char *buf
, size_t length
)
4603 if (any_slab_objects(s
))
4606 s
->flags
&= ~SLAB_STORE_USER
;
4607 if (buf
[0] == '1') {
4608 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4609 s
->flags
|= SLAB_STORE_USER
;
4611 calculate_sizes(s
, -1);
4614 SLAB_ATTR(store_user
);
4616 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4621 static ssize_t
validate_store(struct kmem_cache
*s
,
4622 const char *buf
, size_t length
)
4626 if (buf
[0] == '1') {
4627 ret
= validate_slab_cache(s
);
4633 SLAB_ATTR(validate
);
4635 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4637 if (!(s
->flags
& SLAB_STORE_USER
))
4639 return list_locations(s
, buf
, TRACK_ALLOC
);
4641 SLAB_ATTR_RO(alloc_calls
);
4643 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4645 if (!(s
->flags
& SLAB_STORE_USER
))
4647 return list_locations(s
, buf
, TRACK_FREE
);
4649 SLAB_ATTR_RO(free_calls
);
4650 #endif /* CONFIG_SLUB_DEBUG */
4652 #ifdef CONFIG_FAILSLAB
4653 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
4655 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
4658 static ssize_t
failslab_store(struct kmem_cache
*s
, const char *buf
,
4661 if (s
->refcount
> 1)
4664 s
->flags
&= ~SLAB_FAILSLAB
;
4666 s
->flags
|= SLAB_FAILSLAB
;
4669 SLAB_ATTR(failslab
);
4672 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4677 static ssize_t
shrink_store(struct kmem_cache
*s
,
4678 const char *buf
, size_t length
)
4680 if (buf
[0] == '1') {
4681 int rc
= kmem_cache_shrink(s
);
4692 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4694 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4697 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4698 const char *buf
, size_t length
)
4700 unsigned long ratio
;
4703 err
= kstrtoul(buf
, 10, &ratio
);
4708 s
->remote_node_defrag_ratio
= ratio
* 10;
4712 SLAB_ATTR(remote_node_defrag_ratio
);
4715 #ifdef CONFIG_SLUB_STATS
4716 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
4718 unsigned long sum
= 0;
4721 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
4726 for_each_online_cpu(cpu
) {
4727 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
4733 len
= sprintf(buf
, "%lu", sum
);
4736 for_each_online_cpu(cpu
) {
4737 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
4738 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
4742 return len
+ sprintf(buf
+ len
, "\n");
4745 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
4749 for_each_online_cpu(cpu
)
4750 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
4753 #define STAT_ATTR(si, text) \
4754 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4756 return show_stat(s, buf, si); \
4758 static ssize_t text##_store(struct kmem_cache *s, \
4759 const char *buf, size_t length) \
4761 if (buf[0] != '0') \
4763 clear_stat(s, si); \
4768 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4769 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
4770 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
4771 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
4772 STAT_ATTR(FREE_FROZEN
, free_frozen
);
4773 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
4774 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
4775 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
4776 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
4777 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
4778 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
4779 STAT_ATTR(FREE_SLAB
, free_slab
);
4780 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
4781 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
4782 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
4783 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4784 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4785 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4786 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
4787 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
4788 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
4789 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
4790 STAT_ATTR(CPU_PARTIAL_ALLOC
, cpu_partial_alloc
);
4791 STAT_ATTR(CPU_PARTIAL_FREE
, cpu_partial_free
);
4792 STAT_ATTR(CPU_PARTIAL_NODE
, cpu_partial_node
);
4793 STAT_ATTR(CPU_PARTIAL_DRAIN
, cpu_partial_drain
);
4796 static struct attribute
*slab_attrs
[] = {
4797 &slab_size_attr
.attr
,
4798 &object_size_attr
.attr
,
4799 &objs_per_slab_attr
.attr
,
4801 &min_partial_attr
.attr
,
4802 &cpu_partial_attr
.attr
,
4804 &objects_partial_attr
.attr
,
4806 &cpu_slabs_attr
.attr
,
4810 &hwcache_align_attr
.attr
,
4811 &reclaim_account_attr
.attr
,
4812 &destroy_by_rcu_attr
.attr
,
4814 &reserved_attr
.attr
,
4815 &slabs_cpu_partial_attr
.attr
,
4816 #ifdef CONFIG_SLUB_DEBUG
4817 &total_objects_attr
.attr
,
4819 &sanity_checks_attr
.attr
,
4821 &red_zone_attr
.attr
,
4823 &store_user_attr
.attr
,
4824 &validate_attr
.attr
,
4825 &alloc_calls_attr
.attr
,
4826 &free_calls_attr
.attr
,
4828 #ifdef CONFIG_ZONE_DMA
4829 &cache_dma_attr
.attr
,
4832 &remote_node_defrag_ratio_attr
.attr
,
4834 #ifdef CONFIG_SLUB_STATS
4835 &alloc_fastpath_attr
.attr
,
4836 &alloc_slowpath_attr
.attr
,
4837 &free_fastpath_attr
.attr
,
4838 &free_slowpath_attr
.attr
,
4839 &free_frozen_attr
.attr
,
4840 &free_add_partial_attr
.attr
,
4841 &free_remove_partial_attr
.attr
,
4842 &alloc_from_partial_attr
.attr
,
4843 &alloc_slab_attr
.attr
,
4844 &alloc_refill_attr
.attr
,
4845 &alloc_node_mismatch_attr
.attr
,
4846 &free_slab_attr
.attr
,
4847 &cpuslab_flush_attr
.attr
,
4848 &deactivate_full_attr
.attr
,
4849 &deactivate_empty_attr
.attr
,
4850 &deactivate_to_head_attr
.attr
,
4851 &deactivate_to_tail_attr
.attr
,
4852 &deactivate_remote_frees_attr
.attr
,
4853 &deactivate_bypass_attr
.attr
,
4854 &order_fallback_attr
.attr
,
4855 &cmpxchg_double_fail_attr
.attr
,
4856 &cmpxchg_double_cpu_fail_attr
.attr
,
4857 &cpu_partial_alloc_attr
.attr
,
4858 &cpu_partial_free_attr
.attr
,
4859 &cpu_partial_node_attr
.attr
,
4860 &cpu_partial_drain_attr
.attr
,
4862 #ifdef CONFIG_FAILSLAB
4863 &failslab_attr
.attr
,
4869 static struct attribute_group slab_attr_group
= {
4870 .attrs
= slab_attrs
,
4873 static ssize_t
slab_attr_show(struct kobject
*kobj
,
4874 struct attribute
*attr
,
4877 struct slab_attribute
*attribute
;
4878 struct kmem_cache
*s
;
4881 attribute
= to_slab_attr(attr
);
4884 if (!attribute
->show
)
4887 err
= attribute
->show(s
, buf
);
4892 static ssize_t
slab_attr_store(struct kobject
*kobj
,
4893 struct attribute
*attr
,
4894 const char *buf
, size_t len
)
4896 struct slab_attribute
*attribute
;
4897 struct kmem_cache
*s
;
4900 attribute
= to_slab_attr(attr
);
4903 if (!attribute
->store
)
4906 err
= attribute
->store(s
, buf
, len
);
4907 #ifdef CONFIG_MEMCG_KMEM
4908 if (slab_state
>= FULL
&& err
>= 0 && is_root_cache(s
)) {
4911 mutex_lock(&slab_mutex
);
4912 if (s
->max_attr_size
< len
)
4913 s
->max_attr_size
= len
;
4916 * This is a best effort propagation, so this function's return
4917 * value will be determined by the parent cache only. This is
4918 * basically because not all attributes will have a well
4919 * defined semantics for rollbacks - most of the actions will
4920 * have permanent effects.
4922 * Returning the error value of any of the children that fail
4923 * is not 100 % defined, in the sense that users seeing the
4924 * error code won't be able to know anything about the state of
4927 * Only returning the error code for the parent cache at least
4928 * has well defined semantics. The cache being written to
4929 * directly either failed or succeeded, in which case we loop
4930 * through the descendants with best-effort propagation.
4932 for_each_memcg_cache_index(i
) {
4933 struct kmem_cache
*c
= cache_from_memcg_idx(s
, i
);
4935 attribute
->store(c
, buf
, len
);
4937 mutex_unlock(&slab_mutex
);
4943 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
)
4945 #ifdef CONFIG_MEMCG_KMEM
4947 char *buffer
= NULL
;
4948 struct kmem_cache
*root_cache
;
4950 if (is_root_cache(s
))
4953 root_cache
= s
->memcg_params
->root_cache
;
4956 * This mean this cache had no attribute written. Therefore, no point
4957 * in copying default values around
4959 if (!root_cache
->max_attr_size
)
4962 for (i
= 0; i
< ARRAY_SIZE(slab_attrs
); i
++) {
4965 struct slab_attribute
*attr
= to_slab_attr(slab_attrs
[i
]);
4967 if (!attr
|| !attr
->store
|| !attr
->show
)
4971 * It is really bad that we have to allocate here, so we will
4972 * do it only as a fallback. If we actually allocate, though,
4973 * we can just use the allocated buffer until the end.
4975 * Most of the slub attributes will tend to be very small in
4976 * size, but sysfs allows buffers up to a page, so they can
4977 * theoretically happen.
4981 else if (root_cache
->max_attr_size
< ARRAY_SIZE(mbuf
))
4984 buffer
= (char *) get_zeroed_page(GFP_KERNEL
);
4985 if (WARN_ON(!buffer
))
4990 attr
->show(root_cache
, buf
);
4991 attr
->store(s
, buf
, strlen(buf
));
4995 free_page((unsigned long)buffer
);
4999 static void kmem_cache_release(struct kobject
*k
)
5001 slab_kmem_cache_release(to_slab(k
));
5004 static const struct sysfs_ops slab_sysfs_ops
= {
5005 .show
= slab_attr_show
,
5006 .store
= slab_attr_store
,
5009 static struct kobj_type slab_ktype
= {
5010 .sysfs_ops
= &slab_sysfs_ops
,
5011 .release
= kmem_cache_release
,
5014 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
5016 struct kobj_type
*ktype
= get_ktype(kobj
);
5018 if (ktype
== &slab_ktype
)
5023 static const struct kset_uevent_ops slab_uevent_ops
= {
5024 .filter
= uevent_filter
,
5027 static struct kset
*slab_kset
;
5029 static inline struct kset
*cache_kset(struct kmem_cache
*s
)
5031 #ifdef CONFIG_MEMCG_KMEM
5032 if (!is_root_cache(s
))
5033 return s
->memcg_params
->root_cache
->memcg_kset
;
5038 #define ID_STR_LENGTH 64
5040 /* Create a unique string id for a slab cache:
5042 * Format :[flags-]size
5044 static char *create_unique_id(struct kmem_cache
*s
)
5046 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
5053 * First flags affecting slabcache operations. We will only
5054 * get here for aliasable slabs so we do not need to support
5055 * too many flags. The flags here must cover all flags that
5056 * are matched during merging to guarantee that the id is
5059 if (s
->flags
& SLAB_CACHE_DMA
)
5061 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
5063 if (s
->flags
& SLAB_DEBUG_FREE
)
5065 if (!(s
->flags
& SLAB_NOTRACK
))
5069 p
+= sprintf(p
, "%07d", s
->size
);
5071 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
5075 static int sysfs_slab_add(struct kmem_cache
*s
)
5079 int unmergeable
= slab_unmergeable(s
);
5083 * Slabcache can never be merged so we can use the name proper.
5084 * This is typically the case for debug situations. In that
5085 * case we can catch duplicate names easily.
5087 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
5091 * Create a unique name for the slab as a target
5094 name
= create_unique_id(s
);
5097 s
->kobj
.kset
= cache_kset(s
);
5098 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, "%s", name
);
5102 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
5106 #ifdef CONFIG_MEMCG_KMEM
5107 if (is_root_cache(s
)) {
5108 s
->memcg_kset
= kset_create_and_add("cgroup", NULL
, &s
->kobj
);
5109 if (!s
->memcg_kset
) {
5116 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
5118 /* Setup first alias */
5119 sysfs_slab_alias(s
, s
->name
);
5126 kobject_del(&s
->kobj
);
5128 kobject_put(&s
->kobj
);
5132 void sysfs_slab_remove(struct kmem_cache
*s
)
5134 if (slab_state
< FULL
)
5136 * Sysfs has not been setup yet so no need to remove the
5141 #ifdef CONFIG_MEMCG_KMEM
5142 kset_unregister(s
->memcg_kset
);
5144 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
5145 kobject_del(&s
->kobj
);
5146 kobject_put(&s
->kobj
);
5150 * Need to buffer aliases during bootup until sysfs becomes
5151 * available lest we lose that information.
5153 struct saved_alias
{
5154 struct kmem_cache
*s
;
5156 struct saved_alias
*next
;
5159 static struct saved_alias
*alias_list
;
5161 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5163 struct saved_alias
*al
;
5165 if (slab_state
== FULL
) {
5167 * If we have a leftover link then remove it.
5169 sysfs_remove_link(&slab_kset
->kobj
, name
);
5170 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5173 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5179 al
->next
= alias_list
;
5184 static int __init
slab_sysfs_init(void)
5186 struct kmem_cache
*s
;
5189 mutex_lock(&slab_mutex
);
5191 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
5193 mutex_unlock(&slab_mutex
);
5194 pr_err("Cannot register slab subsystem.\n");
5200 list_for_each_entry(s
, &slab_caches
, list
) {
5201 err
= sysfs_slab_add(s
);
5203 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5207 while (alias_list
) {
5208 struct saved_alias
*al
= alias_list
;
5210 alias_list
= alias_list
->next
;
5211 err
= sysfs_slab_alias(al
->s
, al
->name
);
5213 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5218 mutex_unlock(&slab_mutex
);
5223 __initcall(slab_sysfs_init
);
5224 #endif /* CONFIG_SYSFS */
5227 * The /proc/slabinfo ABI
5229 #ifdef CONFIG_SLABINFO
5230 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
)
5232 unsigned long nr_slabs
= 0;
5233 unsigned long nr_objs
= 0;
5234 unsigned long nr_free
= 0;
5236 struct kmem_cache_node
*n
;
5238 for_each_kmem_cache_node(s
, node
, n
) {
5239 nr_slabs
+= node_nr_slabs(n
);
5240 nr_objs
+= node_nr_objs(n
);
5241 nr_free
+= count_partial(n
, count_free
);
5244 sinfo
->active_objs
= nr_objs
- nr_free
;
5245 sinfo
->num_objs
= nr_objs
;
5246 sinfo
->active_slabs
= nr_slabs
;
5247 sinfo
->num_slabs
= nr_slabs
;
5248 sinfo
->objects_per_slab
= oo_objects(s
->oo
);
5249 sinfo
->cache_order
= oo_order(s
->oo
);
5252 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
)
5256 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
5257 size_t count
, loff_t
*ppos
)
5261 #endif /* CONFIG_SLABINFO */