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_hardwall(zone
, flags
) &&
1669 n
->nr_partial
> s
->min_partial
) {
1670 object
= get_partial_node(s
, n
, c
, flags
);
1673 * Don't check read_mems_allowed_retry()
1674 * here - if mems_allowed was updated in
1675 * parallel, that was a harmless race
1676 * between allocation and the cpuset
1683 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1689 * Get a partial page, lock it and return it.
1691 static void *get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
,
1692 struct kmem_cache_cpu
*c
)
1695 int searchnode
= node
;
1697 if (node
== NUMA_NO_NODE
)
1698 searchnode
= numa_mem_id();
1699 else if (!node_present_pages(node
))
1700 searchnode
= node_to_mem_node(node
);
1702 object
= get_partial_node(s
, get_node(s
, searchnode
), c
, flags
);
1703 if (object
|| node
!= NUMA_NO_NODE
)
1706 return get_any_partial(s
, flags
, c
);
1709 #ifdef CONFIG_PREEMPT
1711 * Calculate the next globally unique transaction for disambiguiation
1712 * during cmpxchg. The transactions start with the cpu number and are then
1713 * incremented by CONFIG_NR_CPUS.
1715 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1718 * No preemption supported therefore also no need to check for
1724 static inline unsigned long next_tid(unsigned long tid
)
1726 return tid
+ TID_STEP
;
1729 static inline unsigned int tid_to_cpu(unsigned long tid
)
1731 return tid
% TID_STEP
;
1734 static inline unsigned long tid_to_event(unsigned long tid
)
1736 return tid
/ TID_STEP
;
1739 static inline unsigned int init_tid(int cpu
)
1744 static inline void note_cmpxchg_failure(const char *n
,
1745 const struct kmem_cache
*s
, unsigned long tid
)
1747 #ifdef SLUB_DEBUG_CMPXCHG
1748 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
1750 pr_info("%s %s: cmpxchg redo ", n
, s
->name
);
1752 #ifdef CONFIG_PREEMPT
1753 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
1754 pr_warn("due to cpu change %d -> %d\n",
1755 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
1758 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
1759 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1760 tid_to_event(tid
), tid_to_event(actual_tid
));
1762 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1763 actual_tid
, tid
, next_tid(tid
));
1765 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
1768 static void init_kmem_cache_cpus(struct kmem_cache
*s
)
1772 for_each_possible_cpu(cpu
)
1773 per_cpu_ptr(s
->cpu_slab
, cpu
)->tid
= init_tid(cpu
);
1777 * Remove the cpu slab
1779 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
,
1782 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
1783 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1785 enum slab_modes l
= M_NONE
, m
= M_NONE
;
1787 int tail
= DEACTIVATE_TO_HEAD
;
1791 if (page
->freelist
) {
1792 stat(s
, DEACTIVATE_REMOTE_FREES
);
1793 tail
= DEACTIVATE_TO_TAIL
;
1797 * Stage one: Free all available per cpu objects back
1798 * to the page freelist while it is still frozen. Leave the
1801 * There is no need to take the list->lock because the page
1804 while (freelist
&& (nextfree
= get_freepointer(s
, freelist
))) {
1806 unsigned long counters
;
1809 prior
= page
->freelist
;
1810 counters
= page
->counters
;
1811 set_freepointer(s
, freelist
, prior
);
1812 new.counters
= counters
;
1814 VM_BUG_ON(!new.frozen
);
1816 } while (!__cmpxchg_double_slab(s
, page
,
1818 freelist
, new.counters
,
1819 "drain percpu freelist"));
1821 freelist
= nextfree
;
1825 * Stage two: Ensure that the page is unfrozen while the
1826 * list presence reflects the actual number of objects
1829 * We setup the list membership and then perform a cmpxchg
1830 * with the count. If there is a mismatch then the page
1831 * is not unfrozen but the page is on the wrong list.
1833 * Then we restart the process which may have to remove
1834 * the page from the list that we just put it on again
1835 * because the number of objects in the slab may have
1840 old
.freelist
= page
->freelist
;
1841 old
.counters
= page
->counters
;
1842 VM_BUG_ON(!old
.frozen
);
1844 /* Determine target state of the slab */
1845 new.counters
= old
.counters
;
1848 set_freepointer(s
, freelist
, old
.freelist
);
1849 new.freelist
= freelist
;
1851 new.freelist
= old
.freelist
;
1855 if (!new.inuse
&& n
->nr_partial
>= s
->min_partial
)
1857 else if (new.freelist
) {
1862 * Taking the spinlock removes the possiblity
1863 * that acquire_slab() will see a slab page that
1866 spin_lock(&n
->list_lock
);
1870 if (kmem_cache_debug(s
) && !lock
) {
1873 * This also ensures that the scanning of full
1874 * slabs from diagnostic functions will not see
1877 spin_lock(&n
->list_lock
);
1885 remove_partial(n
, page
);
1887 else if (l
== M_FULL
)
1889 remove_full(s
, n
, page
);
1891 if (m
== M_PARTIAL
) {
1893 add_partial(n
, page
, tail
);
1896 } else if (m
== M_FULL
) {
1898 stat(s
, DEACTIVATE_FULL
);
1899 add_full(s
, n
, page
);
1905 if (!__cmpxchg_double_slab(s
, page
,
1906 old
.freelist
, old
.counters
,
1907 new.freelist
, new.counters
,
1912 spin_unlock(&n
->list_lock
);
1915 stat(s
, DEACTIVATE_EMPTY
);
1916 discard_slab(s
, page
);
1922 * Unfreeze all the cpu partial slabs.
1924 * This function must be called with interrupts disabled
1925 * for the cpu using c (or some other guarantee must be there
1926 * to guarantee no concurrent accesses).
1928 static void unfreeze_partials(struct kmem_cache
*s
,
1929 struct kmem_cache_cpu
*c
)
1931 #ifdef CONFIG_SLUB_CPU_PARTIAL
1932 struct kmem_cache_node
*n
= NULL
, *n2
= NULL
;
1933 struct page
*page
, *discard_page
= NULL
;
1935 while ((page
= c
->partial
)) {
1939 c
->partial
= page
->next
;
1941 n2
= get_node(s
, page_to_nid(page
));
1944 spin_unlock(&n
->list_lock
);
1947 spin_lock(&n
->list_lock
);
1952 old
.freelist
= page
->freelist
;
1953 old
.counters
= page
->counters
;
1954 VM_BUG_ON(!old
.frozen
);
1956 new.counters
= old
.counters
;
1957 new.freelist
= old
.freelist
;
1961 } while (!__cmpxchg_double_slab(s
, page
,
1962 old
.freelist
, old
.counters
,
1963 new.freelist
, new.counters
,
1964 "unfreezing slab"));
1966 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
)) {
1967 page
->next
= discard_page
;
1968 discard_page
= page
;
1970 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
1971 stat(s
, FREE_ADD_PARTIAL
);
1976 spin_unlock(&n
->list_lock
);
1978 while (discard_page
) {
1979 page
= discard_page
;
1980 discard_page
= discard_page
->next
;
1982 stat(s
, DEACTIVATE_EMPTY
);
1983 discard_slab(s
, page
);
1990 * Put a page that was just frozen (in __slab_free) into a partial page
1991 * slot if available. This is done without interrupts disabled and without
1992 * preemption disabled. The cmpxchg is racy and may put the partial page
1993 * onto a random cpus partial slot.
1995 * If we did not find a slot then simply move all the partials to the
1996 * per node partial list.
1998 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
)
2000 #ifdef CONFIG_SLUB_CPU_PARTIAL
2001 struct page
*oldpage
;
2008 oldpage
= this_cpu_read(s
->cpu_slab
->partial
);
2011 pobjects
= oldpage
->pobjects
;
2012 pages
= oldpage
->pages
;
2013 if (drain
&& pobjects
> s
->cpu_partial
) {
2014 unsigned long flags
;
2016 * partial array is full. Move the existing
2017 * set to the per node partial list.
2019 local_irq_save(flags
);
2020 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2021 local_irq_restore(flags
);
2025 stat(s
, CPU_PARTIAL_DRAIN
);
2030 pobjects
+= page
->objects
- page
->inuse
;
2032 page
->pages
= pages
;
2033 page
->pobjects
= pobjects
;
2034 page
->next
= oldpage
;
2036 } while (this_cpu_cmpxchg(s
->cpu_slab
->partial
, oldpage
, page
)
2041 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
2043 stat(s
, CPUSLAB_FLUSH
);
2044 deactivate_slab(s
, c
->page
, c
->freelist
);
2046 c
->tid
= next_tid(c
->tid
);
2054 * Called from IPI handler with interrupts disabled.
2056 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
2058 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2064 unfreeze_partials(s
, c
);
2068 static void flush_cpu_slab(void *d
)
2070 struct kmem_cache
*s
= d
;
2072 __flush_cpu_slab(s
, smp_processor_id());
2075 static bool has_cpu_slab(int cpu
, void *info
)
2077 struct kmem_cache
*s
= info
;
2078 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2080 return c
->page
|| c
->partial
;
2083 static void flush_all(struct kmem_cache
*s
)
2085 on_each_cpu_cond(has_cpu_slab
, flush_cpu_slab
, s
, 1, GFP_ATOMIC
);
2089 * Check if the objects in a per cpu structure fit numa
2090 * locality expectations.
2092 static inline int node_match(struct page
*page
, int node
)
2095 if (!page
|| (node
!= NUMA_NO_NODE
&& page_to_nid(page
) != node
))
2101 #ifdef CONFIG_SLUB_DEBUG
2102 static int count_free(struct page
*page
)
2104 return page
->objects
- page
->inuse
;
2107 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
2109 return atomic_long_read(&n
->total_objects
);
2111 #endif /* CONFIG_SLUB_DEBUG */
2113 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2114 static unsigned long count_partial(struct kmem_cache_node
*n
,
2115 int (*get_count
)(struct page
*))
2117 unsigned long flags
;
2118 unsigned long x
= 0;
2121 spin_lock_irqsave(&n
->list_lock
, flags
);
2122 list_for_each_entry(page
, &n
->partial
, lru
)
2123 x
+= get_count(page
);
2124 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2127 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2129 static noinline
void
2130 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
2132 #ifdef CONFIG_SLUB_DEBUG
2133 static DEFINE_RATELIMIT_STATE(slub_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2134 DEFAULT_RATELIMIT_BURST
);
2136 struct kmem_cache_node
*n
;
2138 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slub_oom_rs
))
2141 pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2143 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2144 s
->name
, s
->object_size
, s
->size
, oo_order(s
->oo
),
2147 if (oo_order(s
->min
) > get_order(s
->object_size
))
2148 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2151 for_each_kmem_cache_node(s
, node
, n
) {
2152 unsigned long nr_slabs
;
2153 unsigned long nr_objs
;
2154 unsigned long nr_free
;
2156 nr_free
= count_partial(n
, count_free
);
2157 nr_slabs
= node_nr_slabs(n
);
2158 nr_objs
= node_nr_objs(n
);
2160 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2161 node
, nr_slabs
, nr_objs
, nr_free
);
2166 static inline void *new_slab_objects(struct kmem_cache
*s
, gfp_t flags
,
2167 int node
, struct kmem_cache_cpu
**pc
)
2170 struct kmem_cache_cpu
*c
= *pc
;
2173 freelist
= get_partial(s
, flags
, node
, c
);
2178 page
= new_slab(s
, flags
, node
);
2180 c
= raw_cpu_ptr(s
->cpu_slab
);
2185 * No other reference to the page yet so we can
2186 * muck around with it freely without cmpxchg
2188 freelist
= page
->freelist
;
2189 page
->freelist
= NULL
;
2191 stat(s
, ALLOC_SLAB
);
2200 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
)
2202 if (unlikely(PageSlabPfmemalloc(page
)))
2203 return gfp_pfmemalloc_allowed(gfpflags
);
2209 * Check the page->freelist of a page and either transfer the freelist to the
2210 * per cpu freelist or deactivate the page.
2212 * The page is still frozen if the return value is not NULL.
2214 * If this function returns NULL then the page has been unfrozen.
2216 * This function must be called with interrupt disabled.
2218 static inline void *get_freelist(struct kmem_cache
*s
, struct page
*page
)
2221 unsigned long counters
;
2225 freelist
= page
->freelist
;
2226 counters
= page
->counters
;
2228 new.counters
= counters
;
2229 VM_BUG_ON(!new.frozen
);
2231 new.inuse
= page
->objects
;
2232 new.frozen
= freelist
!= NULL
;
2234 } while (!__cmpxchg_double_slab(s
, page
,
2243 * Slow path. The lockless freelist is empty or we need to perform
2246 * Processing is still very fast if new objects have been freed to the
2247 * regular freelist. In that case we simply take over the regular freelist
2248 * as the lockless freelist and zap the regular freelist.
2250 * If that is not working then we fall back to the partial lists. We take the
2251 * first element of the freelist as the object to allocate now and move the
2252 * rest of the freelist to the lockless freelist.
2254 * And if we were unable to get a new slab from the partial slab lists then
2255 * we need to allocate a new slab. This is the slowest path since it involves
2256 * a call to the page allocator and the setup of a new slab.
2258 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2259 unsigned long addr
, struct kmem_cache_cpu
*c
)
2263 unsigned long flags
;
2265 local_irq_save(flags
);
2266 #ifdef CONFIG_PREEMPT
2268 * We may have been preempted and rescheduled on a different
2269 * cpu before disabling interrupts. Need to reload cpu area
2272 c
= this_cpu_ptr(s
->cpu_slab
);
2280 if (unlikely(!node_match(page
, node
))) {
2281 int searchnode
= node
;
2283 if (node
!= NUMA_NO_NODE
&& !node_present_pages(node
))
2284 searchnode
= node_to_mem_node(node
);
2286 if (unlikely(!node_match(page
, searchnode
))) {
2287 stat(s
, ALLOC_NODE_MISMATCH
);
2288 deactivate_slab(s
, page
, c
->freelist
);
2296 * By rights, we should be searching for a slab page that was
2297 * PFMEMALLOC but right now, we are losing the pfmemalloc
2298 * information when the page leaves the per-cpu allocator
2300 if (unlikely(!pfmemalloc_match(page
, gfpflags
))) {
2301 deactivate_slab(s
, page
, c
->freelist
);
2307 /* must check again c->freelist in case of cpu migration or IRQ */
2308 freelist
= c
->freelist
;
2312 freelist
= get_freelist(s
, page
);
2316 stat(s
, DEACTIVATE_BYPASS
);
2320 stat(s
, ALLOC_REFILL
);
2324 * freelist is pointing to the list of objects to be used.
2325 * page is pointing to the page from which the objects are obtained.
2326 * That page must be frozen for per cpu allocations to work.
2328 VM_BUG_ON(!c
->page
->frozen
);
2329 c
->freelist
= get_freepointer(s
, freelist
);
2330 c
->tid
= next_tid(c
->tid
);
2331 local_irq_restore(flags
);
2337 page
= c
->page
= c
->partial
;
2338 c
->partial
= page
->next
;
2339 stat(s
, CPU_PARTIAL_ALLOC
);
2344 freelist
= new_slab_objects(s
, gfpflags
, node
, &c
);
2346 if (unlikely(!freelist
)) {
2347 slab_out_of_memory(s
, gfpflags
, node
);
2348 local_irq_restore(flags
);
2353 if (likely(!kmem_cache_debug(s
) && pfmemalloc_match(page
, gfpflags
)))
2356 /* Only entered in the debug case */
2357 if (kmem_cache_debug(s
) &&
2358 !alloc_debug_processing(s
, page
, freelist
, addr
))
2359 goto new_slab
; /* Slab failed checks. Next slab needed */
2361 deactivate_slab(s
, page
, get_freepointer(s
, freelist
));
2364 local_irq_restore(flags
);
2369 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2370 * have the fastpath folded into their functions. So no function call
2371 * overhead for requests that can be satisfied on the fastpath.
2373 * The fastpath works by first checking if the lockless freelist can be used.
2374 * If not then __slab_alloc is called for slow processing.
2376 * Otherwise we can simply pick the next object from the lockless free list.
2378 static __always_inline
void *slab_alloc_node(struct kmem_cache
*s
,
2379 gfp_t gfpflags
, int node
, unsigned long addr
)
2382 struct kmem_cache_cpu
*c
;
2386 if (slab_pre_alloc_hook(s
, gfpflags
))
2389 s
= memcg_kmem_get_cache(s
, gfpflags
);
2392 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2393 * enabled. We may switch back and forth between cpus while
2394 * reading from one cpu area. That does not matter as long
2395 * as we end up on the original cpu again when doing the cmpxchg.
2397 * Preemption is disabled for the retrieval of the tid because that
2398 * must occur from the current processor. We cannot allow rescheduling
2399 * on a different processor between the determination of the pointer
2400 * and the retrieval of the tid.
2403 c
= this_cpu_ptr(s
->cpu_slab
);
2406 * The transaction ids are globally unique per cpu and per operation on
2407 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2408 * occurs on the right processor and that there was no operation on the
2409 * linked list in between.
2414 object
= c
->freelist
;
2416 if (unlikely(!object
|| !node_match(page
, node
))) {
2417 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
2418 stat(s
, ALLOC_SLOWPATH
);
2420 void *next_object
= get_freepointer_safe(s
, object
);
2423 * The cmpxchg will only match if there was no additional
2424 * operation and if we are on the right processor.
2426 * The cmpxchg does the following atomically (without lock
2428 * 1. Relocate first pointer to the current per cpu area.
2429 * 2. Verify that tid and freelist have not been changed
2430 * 3. If they were not changed replace tid and freelist
2432 * Since this is without lock semantics the protection is only
2433 * against code executing on this cpu *not* from access by
2436 if (unlikely(!this_cpu_cmpxchg_double(
2437 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2439 next_object
, next_tid(tid
)))) {
2441 note_cmpxchg_failure("slab_alloc", s
, tid
);
2444 prefetch_freepointer(s
, next_object
);
2445 stat(s
, ALLOC_FASTPATH
);
2448 if (unlikely(gfpflags
& __GFP_ZERO
) && object
)
2449 memset(object
, 0, s
->object_size
);
2451 slab_post_alloc_hook(s
, gfpflags
, object
);
2456 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
2457 gfp_t gfpflags
, unsigned long addr
)
2459 return slab_alloc_node(s
, gfpflags
, NUMA_NO_NODE
, addr
);
2462 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
2464 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2466 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->object_size
,
2471 EXPORT_SYMBOL(kmem_cache_alloc
);
2473 #ifdef CONFIG_TRACING
2474 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
2476 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2477 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
2480 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
2484 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
2486 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2488 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
2489 s
->object_size
, s
->size
, gfpflags
, node
);
2493 EXPORT_SYMBOL(kmem_cache_alloc_node
);
2495 #ifdef CONFIG_TRACING
2496 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
2498 int node
, size_t size
)
2500 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2502 trace_kmalloc_node(_RET_IP_
, ret
,
2503 size
, s
->size
, gfpflags
, node
);
2506 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
2511 * Slow patch handling. This may still be called frequently since objects
2512 * have a longer lifetime than the cpu slabs in most processing loads.
2514 * So we still attempt to reduce cache line usage. Just take the slab
2515 * lock and free the item. If there is no additional partial page
2516 * handling required then we can return immediately.
2518 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
2519 void *x
, unsigned long addr
)
2522 void **object
= (void *)x
;
2525 unsigned long counters
;
2526 struct kmem_cache_node
*n
= NULL
;
2527 unsigned long uninitialized_var(flags
);
2529 stat(s
, FREE_SLOWPATH
);
2531 if (kmem_cache_debug(s
) &&
2532 !(n
= free_debug_processing(s
, page
, x
, addr
, &flags
)))
2537 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2540 prior
= page
->freelist
;
2541 counters
= page
->counters
;
2542 set_freepointer(s
, object
, prior
);
2543 new.counters
= counters
;
2544 was_frozen
= new.frozen
;
2546 if ((!new.inuse
|| !prior
) && !was_frozen
) {
2548 if (kmem_cache_has_cpu_partial(s
) && !prior
) {
2551 * Slab was on no list before and will be
2553 * We can defer the list move and instead
2558 } else { /* Needs to be taken off a list */
2560 n
= get_node(s
, page_to_nid(page
));
2562 * Speculatively acquire the list_lock.
2563 * If the cmpxchg does not succeed then we may
2564 * drop the list_lock without any processing.
2566 * Otherwise the list_lock will synchronize with
2567 * other processors updating the list of slabs.
2569 spin_lock_irqsave(&n
->list_lock
, flags
);
2574 } while (!cmpxchg_double_slab(s
, page
,
2576 object
, new.counters
,
2582 * If we just froze the page then put it onto the
2583 * per cpu partial list.
2585 if (new.frozen
&& !was_frozen
) {
2586 put_cpu_partial(s
, page
, 1);
2587 stat(s
, CPU_PARTIAL_FREE
);
2590 * The list lock was not taken therefore no list
2591 * activity can be necessary.
2594 stat(s
, FREE_FROZEN
);
2598 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
))
2602 * Objects left in the slab. If it was not on the partial list before
2605 if (!kmem_cache_has_cpu_partial(s
) && unlikely(!prior
)) {
2606 if (kmem_cache_debug(s
))
2607 remove_full(s
, n
, page
);
2608 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2609 stat(s
, FREE_ADD_PARTIAL
);
2611 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2617 * Slab on the partial list.
2619 remove_partial(n
, page
);
2620 stat(s
, FREE_REMOVE_PARTIAL
);
2622 /* Slab must be on the full list */
2623 remove_full(s
, n
, page
);
2626 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2628 discard_slab(s
, page
);
2632 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2633 * can perform fastpath freeing without additional function calls.
2635 * The fastpath is only possible if we are freeing to the current cpu slab
2636 * of this processor. This typically the case if we have just allocated
2639 * If fastpath is not possible then fall back to __slab_free where we deal
2640 * with all sorts of special processing.
2642 static __always_inline
void slab_free(struct kmem_cache
*s
,
2643 struct page
*page
, void *x
, unsigned long addr
)
2645 void **object
= (void *)x
;
2646 struct kmem_cache_cpu
*c
;
2649 slab_free_hook(s
, x
);
2653 * Determine the currently cpus per cpu slab.
2654 * The cpu may change afterward. However that does not matter since
2655 * data is retrieved via this pointer. If we are on the same cpu
2656 * during the cmpxchg then the free will succedd.
2659 c
= this_cpu_ptr(s
->cpu_slab
);
2664 if (likely(page
== c
->page
)) {
2665 set_freepointer(s
, object
, c
->freelist
);
2667 if (unlikely(!this_cpu_cmpxchg_double(
2668 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2670 object
, next_tid(tid
)))) {
2672 note_cmpxchg_failure("slab_free", s
, tid
);
2675 stat(s
, FREE_FASTPATH
);
2677 __slab_free(s
, page
, x
, addr
);
2681 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
2683 s
= cache_from_obj(s
, x
);
2686 slab_free(s
, virt_to_head_page(x
), x
, _RET_IP_
);
2687 trace_kmem_cache_free(_RET_IP_
, x
);
2689 EXPORT_SYMBOL(kmem_cache_free
);
2692 * Object placement in a slab is made very easy because we always start at
2693 * offset 0. If we tune the size of the object to the alignment then we can
2694 * get the required alignment by putting one properly sized object after
2697 * Notice that the allocation order determines the sizes of the per cpu
2698 * caches. Each processor has always one slab available for allocations.
2699 * Increasing the allocation order reduces the number of times that slabs
2700 * must be moved on and off the partial lists and is therefore a factor in
2705 * Mininum / Maximum order of slab pages. This influences locking overhead
2706 * and slab fragmentation. A higher order reduces the number of partial slabs
2707 * and increases the number of allocations possible without having to
2708 * take the list_lock.
2710 static int slub_min_order
;
2711 static int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
2712 static int slub_min_objects
;
2715 * Calculate the order of allocation given an slab object size.
2717 * The order of allocation has significant impact on performance and other
2718 * system components. Generally order 0 allocations should be preferred since
2719 * order 0 does not cause fragmentation in the page allocator. Larger objects
2720 * be problematic to put into order 0 slabs because there may be too much
2721 * unused space left. We go to a higher order if more than 1/16th of the slab
2724 * In order to reach satisfactory performance we must ensure that a minimum
2725 * number of objects is in one slab. Otherwise we may generate too much
2726 * activity on the partial lists which requires taking the list_lock. This is
2727 * less a concern for large slabs though which are rarely used.
2729 * slub_max_order specifies the order where we begin to stop considering the
2730 * number of objects in a slab as critical. If we reach slub_max_order then
2731 * we try to keep the page order as low as possible. So we accept more waste
2732 * of space in favor of a small page order.
2734 * Higher order allocations also allow the placement of more objects in a
2735 * slab and thereby reduce object handling overhead. If the user has
2736 * requested a higher mininum order then we start with that one instead of
2737 * the smallest order which will fit the object.
2739 static inline int slab_order(int size
, int min_objects
,
2740 int max_order
, int fract_leftover
, int reserved
)
2744 int min_order
= slub_min_order
;
2746 if (order_objects(min_order
, size
, reserved
) > MAX_OBJS_PER_PAGE
)
2747 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
2749 for (order
= max(min_order
,
2750 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
2751 order
<= max_order
; order
++) {
2753 unsigned long slab_size
= PAGE_SIZE
<< order
;
2755 if (slab_size
< min_objects
* size
+ reserved
)
2758 rem
= (slab_size
- reserved
) % size
;
2760 if (rem
<= slab_size
/ fract_leftover
)
2768 static inline int calculate_order(int size
, int reserved
)
2776 * Attempt to find best configuration for a slab. This
2777 * works by first attempting to generate a layout with
2778 * the best configuration and backing off gradually.
2780 * First we reduce the acceptable waste in a slab. Then
2781 * we reduce the minimum objects required in a slab.
2783 min_objects
= slub_min_objects
;
2785 min_objects
= 4 * (fls(nr_cpu_ids
) + 1);
2786 max_objects
= order_objects(slub_max_order
, size
, reserved
);
2787 min_objects
= min(min_objects
, max_objects
);
2789 while (min_objects
> 1) {
2791 while (fraction
>= 4) {
2792 order
= slab_order(size
, min_objects
,
2793 slub_max_order
, fraction
, reserved
);
2794 if (order
<= slub_max_order
)
2802 * We were unable to place multiple objects in a slab. Now
2803 * lets see if we can place a single object there.
2805 order
= slab_order(size
, 1, slub_max_order
, 1, reserved
);
2806 if (order
<= slub_max_order
)
2810 * Doh this slab cannot be placed using slub_max_order.
2812 order
= slab_order(size
, 1, MAX_ORDER
, 1, reserved
);
2813 if (order
< MAX_ORDER
)
2819 init_kmem_cache_node(struct kmem_cache_node
*n
)
2822 spin_lock_init(&n
->list_lock
);
2823 INIT_LIST_HEAD(&n
->partial
);
2824 #ifdef CONFIG_SLUB_DEBUG
2825 atomic_long_set(&n
->nr_slabs
, 0);
2826 atomic_long_set(&n
->total_objects
, 0);
2827 INIT_LIST_HEAD(&n
->full
);
2831 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
2833 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
2834 KMALLOC_SHIFT_HIGH
* sizeof(struct kmem_cache_cpu
));
2837 * Must align to double word boundary for the double cmpxchg
2838 * instructions to work; see __pcpu_double_call_return_bool().
2840 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
2841 2 * sizeof(void *));
2846 init_kmem_cache_cpus(s
);
2851 static struct kmem_cache
*kmem_cache_node
;
2854 * No kmalloc_node yet so do it by hand. We know that this is the first
2855 * slab on the node for this slabcache. There are no concurrent accesses
2858 * Note that this function only works on the kmem_cache_node
2859 * when allocating for the kmem_cache_node. This is used for bootstrapping
2860 * memory on a fresh node that has no slab structures yet.
2862 static void early_kmem_cache_node_alloc(int node
)
2865 struct kmem_cache_node
*n
;
2867 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
2869 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
2872 if (page_to_nid(page
) != node
) {
2873 pr_err("SLUB: Unable to allocate memory from node %d\n", node
);
2874 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
2879 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
2882 kmem_cache_node
->node
[node
] = n
;
2883 #ifdef CONFIG_SLUB_DEBUG
2884 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
2885 init_tracking(kmem_cache_node
, n
);
2887 init_kmem_cache_node(n
);
2888 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
2891 * No locks need to be taken here as it has just been
2892 * initialized and there is no concurrent access.
2894 __add_partial(n
, page
, DEACTIVATE_TO_HEAD
);
2897 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2900 struct kmem_cache_node
*n
;
2902 for_each_kmem_cache_node(s
, node
, n
) {
2903 kmem_cache_free(kmem_cache_node
, n
);
2904 s
->node
[node
] = NULL
;
2908 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
2912 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2913 struct kmem_cache_node
*n
;
2915 if (slab_state
== DOWN
) {
2916 early_kmem_cache_node_alloc(node
);
2919 n
= kmem_cache_alloc_node(kmem_cache_node
,
2923 free_kmem_cache_nodes(s
);
2928 init_kmem_cache_node(n
);
2933 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
2935 if (min
< MIN_PARTIAL
)
2937 else if (min
> MAX_PARTIAL
)
2939 s
->min_partial
= min
;
2943 * calculate_sizes() determines the order and the distribution of data within
2946 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
2948 unsigned long flags
= s
->flags
;
2949 unsigned long size
= s
->object_size
;
2953 * Round up object size to the next word boundary. We can only
2954 * place the free pointer at word boundaries and this determines
2955 * the possible location of the free pointer.
2957 size
= ALIGN(size
, sizeof(void *));
2959 #ifdef CONFIG_SLUB_DEBUG
2961 * Determine if we can poison the object itself. If the user of
2962 * the slab may touch the object after free or before allocation
2963 * then we should never poison the object itself.
2965 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
2967 s
->flags
|= __OBJECT_POISON
;
2969 s
->flags
&= ~__OBJECT_POISON
;
2973 * If we are Redzoning then check if there is some space between the
2974 * end of the object and the free pointer. If not then add an
2975 * additional word to have some bytes to store Redzone information.
2977 if ((flags
& SLAB_RED_ZONE
) && size
== s
->object_size
)
2978 size
+= sizeof(void *);
2982 * With that we have determined the number of bytes in actual use
2983 * by the object. This is the potential offset to the free pointer.
2987 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
2990 * Relocate free pointer after the object if it is not
2991 * permitted to overwrite the first word of the object on
2994 * This is the case if we do RCU, have a constructor or
2995 * destructor or are poisoning the objects.
2998 size
+= sizeof(void *);
3001 #ifdef CONFIG_SLUB_DEBUG
3002 if (flags
& SLAB_STORE_USER
)
3004 * Need to store information about allocs and frees after
3007 size
+= 2 * sizeof(struct track
);
3009 if (flags
& SLAB_RED_ZONE
)
3011 * Add some empty padding so that we can catch
3012 * overwrites from earlier objects rather than let
3013 * tracking information or the free pointer be
3014 * corrupted if a user writes before the start
3017 size
+= sizeof(void *);
3021 * SLUB stores one object immediately after another beginning from
3022 * offset 0. In order to align the objects we have to simply size
3023 * each object to conform to the alignment.
3025 size
= ALIGN(size
, s
->align
);
3027 if (forced_order
>= 0)
3028 order
= forced_order
;
3030 order
= calculate_order(size
, s
->reserved
);
3037 s
->allocflags
|= __GFP_COMP
;
3039 if (s
->flags
& SLAB_CACHE_DMA
)
3040 s
->allocflags
|= GFP_DMA
;
3042 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3043 s
->allocflags
|= __GFP_RECLAIMABLE
;
3046 * Determine the number of objects per slab
3048 s
->oo
= oo_make(order
, size
, s
->reserved
);
3049 s
->min
= oo_make(get_order(size
), size
, s
->reserved
);
3050 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
3053 return !!oo_objects(s
->oo
);
3056 static int kmem_cache_open(struct kmem_cache
*s
, unsigned long flags
)
3058 s
->flags
= kmem_cache_flags(s
->size
, flags
, s
->name
, s
->ctor
);
3061 if (need_reserve_slab_rcu
&& (s
->flags
& SLAB_DESTROY_BY_RCU
))
3062 s
->reserved
= sizeof(struct rcu_head
);
3064 if (!calculate_sizes(s
, -1))
3066 if (disable_higher_order_debug
) {
3068 * Disable debugging flags that store metadata if the min slab
3071 if (get_order(s
->size
) > get_order(s
->object_size
)) {
3072 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
3074 if (!calculate_sizes(s
, -1))
3079 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3080 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3081 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_DEBUG_FLAGS
) == 0)
3082 /* Enable fast mode */
3083 s
->flags
|= __CMPXCHG_DOUBLE
;
3087 * The larger the object size is, the more pages we want on the partial
3088 * list to avoid pounding the page allocator excessively.
3090 set_min_partial(s
, ilog2(s
->size
) / 2);
3093 * cpu_partial determined the maximum number of objects kept in the
3094 * per cpu partial lists of a processor.
3096 * Per cpu partial lists mainly contain slabs that just have one
3097 * object freed. If they are used for allocation then they can be
3098 * filled up again with minimal effort. The slab will never hit the
3099 * per node partial lists and therefore no locking will be required.
3101 * This setting also determines
3103 * A) The number of objects from per cpu partial slabs dumped to the
3104 * per node list when we reach the limit.
3105 * B) The number of objects in cpu partial slabs to extract from the
3106 * per node list when we run out of per cpu objects. We only fetch
3107 * 50% to keep some capacity around for frees.
3109 if (!kmem_cache_has_cpu_partial(s
))
3111 else if (s
->size
>= PAGE_SIZE
)
3113 else if (s
->size
>= 1024)
3115 else if (s
->size
>= 256)
3116 s
->cpu_partial
= 13;
3118 s
->cpu_partial
= 30;
3121 s
->remote_node_defrag_ratio
= 1000;
3123 if (!init_kmem_cache_nodes(s
))
3126 if (alloc_kmem_cache_cpus(s
))
3129 free_kmem_cache_nodes(s
);
3131 if (flags
& SLAB_PANIC
)
3132 panic("Cannot create slab %s size=%lu realsize=%u "
3133 "order=%u offset=%u flags=%lx\n",
3134 s
->name
, (unsigned long)s
->size
, s
->size
,
3135 oo_order(s
->oo
), s
->offset
, flags
);
3139 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
3142 #ifdef CONFIG_SLUB_DEBUG
3143 void *addr
= page_address(page
);
3145 unsigned long *map
= kzalloc(BITS_TO_LONGS(page
->objects
) *
3146 sizeof(long), GFP_ATOMIC
);
3149 slab_err(s
, page
, text
, s
->name
);
3152 get_map(s
, page
, map
);
3153 for_each_object(p
, s
, addr
, page
->objects
) {
3155 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
3156 pr_err("INFO: Object 0x%p @offset=%tu\n", p
, p
- addr
);
3157 print_tracking(s
, p
);
3166 * Attempt to free all partial slabs on a node.
3167 * This is called from kmem_cache_close(). We must be the last thread
3168 * using the cache and therefore we do not need to lock anymore.
3170 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
3172 struct page
*page
, *h
;
3174 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
3176 __remove_partial(n
, page
);
3177 discard_slab(s
, page
);
3179 list_slab_objects(s
, page
,
3180 "Objects remaining in %s on kmem_cache_close()");
3186 * Release all resources used by a slab cache.
3188 static inline int kmem_cache_close(struct kmem_cache
*s
)
3191 struct kmem_cache_node
*n
;
3194 /* Attempt to free all objects */
3195 for_each_kmem_cache_node(s
, node
, n
) {
3197 if (n
->nr_partial
|| slabs_node(s
, node
))
3200 free_percpu(s
->cpu_slab
);
3201 free_kmem_cache_nodes(s
);
3205 int __kmem_cache_shutdown(struct kmem_cache
*s
)
3207 return kmem_cache_close(s
);
3210 /********************************************************************
3212 *******************************************************************/
3214 static int __init
setup_slub_min_order(char *str
)
3216 get_option(&str
, &slub_min_order
);
3221 __setup("slub_min_order=", setup_slub_min_order
);
3223 static int __init
setup_slub_max_order(char *str
)
3225 get_option(&str
, &slub_max_order
);
3226 slub_max_order
= min(slub_max_order
, MAX_ORDER
- 1);
3231 __setup("slub_max_order=", setup_slub_max_order
);
3233 static int __init
setup_slub_min_objects(char *str
)
3235 get_option(&str
, &slub_min_objects
);
3240 __setup("slub_min_objects=", setup_slub_min_objects
);
3242 void *__kmalloc(size_t size
, gfp_t flags
)
3244 struct kmem_cache
*s
;
3247 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3248 return kmalloc_large(size
, flags
);
3250 s
= kmalloc_slab(size
, flags
);
3252 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3255 ret
= slab_alloc(s
, flags
, _RET_IP_
);
3257 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
3261 EXPORT_SYMBOL(__kmalloc
);
3264 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
3269 flags
|= __GFP_COMP
| __GFP_NOTRACK
;
3270 page
= alloc_kmem_pages_node(node
, flags
, get_order(size
));
3272 ptr
= page_address(page
);
3274 kmalloc_large_node_hook(ptr
, size
, flags
);
3278 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3280 struct kmem_cache
*s
;
3283 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3284 ret
= kmalloc_large_node(size
, flags
, node
);
3286 trace_kmalloc_node(_RET_IP_
, ret
,
3287 size
, PAGE_SIZE
<< get_order(size
),
3293 s
= kmalloc_slab(size
, flags
);
3295 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3298 ret
= slab_alloc_node(s
, flags
, node
, _RET_IP_
);
3300 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
3304 EXPORT_SYMBOL(__kmalloc_node
);
3307 size_t ksize(const void *object
)
3311 if (unlikely(object
== ZERO_SIZE_PTR
))
3314 page
= virt_to_head_page(object
);
3316 if (unlikely(!PageSlab(page
))) {
3317 WARN_ON(!PageCompound(page
));
3318 return PAGE_SIZE
<< compound_order(page
);
3321 return slab_ksize(page
->slab_cache
);
3323 EXPORT_SYMBOL(ksize
);
3325 void kfree(const void *x
)
3328 void *object
= (void *)x
;
3330 trace_kfree(_RET_IP_
, x
);
3332 if (unlikely(ZERO_OR_NULL_PTR(x
)))
3335 page
= virt_to_head_page(x
);
3336 if (unlikely(!PageSlab(page
))) {
3337 BUG_ON(!PageCompound(page
));
3339 __free_kmem_pages(page
, compound_order(page
));
3342 slab_free(page
->slab_cache
, page
, object
, _RET_IP_
);
3344 EXPORT_SYMBOL(kfree
);
3347 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3348 * the remaining slabs by the number of items in use. The slabs with the
3349 * most items in use come first. New allocations will then fill those up
3350 * and thus they can be removed from the partial lists.
3352 * The slabs with the least items are placed last. This results in them
3353 * being allocated from last increasing the chance that the last objects
3354 * are freed in them.
3356 int __kmem_cache_shrink(struct kmem_cache
*s
)
3360 struct kmem_cache_node
*n
;
3363 int objects
= oo_objects(s
->max
);
3364 struct list_head
*slabs_by_inuse
=
3365 kmalloc(sizeof(struct list_head
) * objects
, GFP_KERNEL
);
3366 unsigned long flags
;
3368 if (!slabs_by_inuse
)
3372 for_each_kmem_cache_node(s
, node
, n
) {
3376 for (i
= 0; i
< objects
; i
++)
3377 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
3379 spin_lock_irqsave(&n
->list_lock
, flags
);
3382 * Build lists indexed by the items in use in each slab.
3384 * Note that concurrent frees may occur while we hold the
3385 * list_lock. page->inuse here is the upper limit.
3387 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
3388 list_move(&page
->lru
, slabs_by_inuse
+ page
->inuse
);
3394 * Rebuild the partial list with the slabs filled up most
3395 * first and the least used slabs at the end.
3397 for (i
= objects
- 1; i
> 0; i
--)
3398 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
3400 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3402 /* Release empty slabs */
3403 list_for_each_entry_safe(page
, t
, slabs_by_inuse
, lru
)
3404 discard_slab(s
, page
);
3407 kfree(slabs_by_inuse
);
3411 static int slab_mem_going_offline_callback(void *arg
)
3413 struct kmem_cache
*s
;
3415 mutex_lock(&slab_mutex
);
3416 list_for_each_entry(s
, &slab_caches
, list
)
3417 __kmem_cache_shrink(s
);
3418 mutex_unlock(&slab_mutex
);
3423 static void slab_mem_offline_callback(void *arg
)
3425 struct kmem_cache_node
*n
;
3426 struct kmem_cache
*s
;
3427 struct memory_notify
*marg
= arg
;
3430 offline_node
= marg
->status_change_nid_normal
;
3433 * If the node still has available memory. we need kmem_cache_node
3436 if (offline_node
< 0)
3439 mutex_lock(&slab_mutex
);
3440 list_for_each_entry(s
, &slab_caches
, list
) {
3441 n
= get_node(s
, offline_node
);
3444 * if n->nr_slabs > 0, slabs still exist on the node
3445 * that is going down. We were unable to free them,
3446 * and offline_pages() function shouldn't call this
3447 * callback. So, we must fail.
3449 BUG_ON(slabs_node(s
, offline_node
));
3451 s
->node
[offline_node
] = NULL
;
3452 kmem_cache_free(kmem_cache_node
, n
);
3455 mutex_unlock(&slab_mutex
);
3458 static int slab_mem_going_online_callback(void *arg
)
3460 struct kmem_cache_node
*n
;
3461 struct kmem_cache
*s
;
3462 struct memory_notify
*marg
= arg
;
3463 int nid
= marg
->status_change_nid_normal
;
3467 * If the node's memory is already available, then kmem_cache_node is
3468 * already created. Nothing to do.
3474 * We are bringing a node online. No memory is available yet. We must
3475 * allocate a kmem_cache_node structure in order to bring the node
3478 mutex_lock(&slab_mutex
);
3479 list_for_each_entry(s
, &slab_caches
, list
) {
3481 * XXX: kmem_cache_alloc_node will fallback to other nodes
3482 * since memory is not yet available from the node that
3485 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
3490 init_kmem_cache_node(n
);
3494 mutex_unlock(&slab_mutex
);
3498 static int slab_memory_callback(struct notifier_block
*self
,
3499 unsigned long action
, void *arg
)
3504 case MEM_GOING_ONLINE
:
3505 ret
= slab_mem_going_online_callback(arg
);
3507 case MEM_GOING_OFFLINE
:
3508 ret
= slab_mem_going_offline_callback(arg
);
3511 case MEM_CANCEL_ONLINE
:
3512 slab_mem_offline_callback(arg
);
3515 case MEM_CANCEL_OFFLINE
:
3519 ret
= notifier_from_errno(ret
);
3525 static struct notifier_block slab_memory_callback_nb
= {
3526 .notifier_call
= slab_memory_callback
,
3527 .priority
= SLAB_CALLBACK_PRI
,
3530 /********************************************************************
3531 * Basic setup of slabs
3532 *******************************************************************/
3535 * Used for early kmem_cache structures that were allocated using
3536 * the page allocator. Allocate them properly then fix up the pointers
3537 * that may be pointing to the wrong kmem_cache structure.
3540 static struct kmem_cache
* __init
bootstrap(struct kmem_cache
*static_cache
)
3543 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
3544 struct kmem_cache_node
*n
;
3546 memcpy(s
, static_cache
, kmem_cache
->object_size
);
3549 * This runs very early, and only the boot processor is supposed to be
3550 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3553 __flush_cpu_slab(s
, smp_processor_id());
3554 for_each_kmem_cache_node(s
, node
, n
) {
3557 list_for_each_entry(p
, &n
->partial
, lru
)
3560 #ifdef CONFIG_SLUB_DEBUG
3561 list_for_each_entry(p
, &n
->full
, lru
)
3565 list_add(&s
->list
, &slab_caches
);
3569 void __init
kmem_cache_init(void)
3571 static __initdata
struct kmem_cache boot_kmem_cache
,
3572 boot_kmem_cache_node
;
3574 if (debug_guardpage_minorder())
3577 kmem_cache_node
= &boot_kmem_cache_node
;
3578 kmem_cache
= &boot_kmem_cache
;
3580 create_boot_cache(kmem_cache_node
, "kmem_cache_node",
3581 sizeof(struct kmem_cache_node
), SLAB_HWCACHE_ALIGN
);
3583 register_hotmemory_notifier(&slab_memory_callback_nb
);
3585 /* Able to allocate the per node structures */
3586 slab_state
= PARTIAL
;
3588 create_boot_cache(kmem_cache
, "kmem_cache",
3589 offsetof(struct kmem_cache
, node
) +
3590 nr_node_ids
* sizeof(struct kmem_cache_node
*),
3591 SLAB_HWCACHE_ALIGN
);
3593 kmem_cache
= bootstrap(&boot_kmem_cache
);
3596 * Allocate kmem_cache_node properly from the kmem_cache slab.
3597 * kmem_cache_node is separately allocated so no need to
3598 * update any list pointers.
3600 kmem_cache_node
= bootstrap(&boot_kmem_cache_node
);
3602 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3603 create_kmalloc_caches(0);
3606 register_cpu_notifier(&slab_notifier
);
3609 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
3611 slub_min_order
, slub_max_order
, slub_min_objects
,
3612 nr_cpu_ids
, nr_node_ids
);
3615 void __init
kmem_cache_init_late(void)
3620 __kmem_cache_alias(const char *name
, size_t size
, size_t align
,
3621 unsigned long flags
, void (*ctor
)(void *))
3623 struct kmem_cache
*s
;
3625 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3628 struct kmem_cache
*c
;
3633 * Adjust the object sizes so that we clear
3634 * the complete object on kzalloc.
3636 s
->object_size
= max(s
->object_size
, (int)size
);
3637 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3639 for_each_memcg_cache_index(i
) {
3640 c
= cache_from_memcg_idx(s
, i
);
3643 c
->object_size
= s
->object_size
;
3644 c
->inuse
= max_t(int, c
->inuse
,
3645 ALIGN(size
, sizeof(void *)));
3648 if (sysfs_slab_alias(s
, name
)) {
3657 int __kmem_cache_create(struct kmem_cache
*s
, unsigned long flags
)
3661 err
= kmem_cache_open(s
, flags
);
3665 /* Mutex is not taken during early boot */
3666 if (slab_state
<= UP
)
3669 memcg_propagate_slab_attrs(s
);
3670 err
= sysfs_slab_add(s
);
3672 kmem_cache_close(s
);
3679 * Use the cpu notifier to insure that the cpu slabs are flushed when
3682 static int slab_cpuup_callback(struct notifier_block
*nfb
,
3683 unsigned long action
, void *hcpu
)
3685 long cpu
= (long)hcpu
;
3686 struct kmem_cache
*s
;
3687 unsigned long flags
;
3690 case CPU_UP_CANCELED
:
3691 case CPU_UP_CANCELED_FROZEN
:
3693 case CPU_DEAD_FROZEN
:
3694 mutex_lock(&slab_mutex
);
3695 list_for_each_entry(s
, &slab_caches
, list
) {
3696 local_irq_save(flags
);
3697 __flush_cpu_slab(s
, cpu
);
3698 local_irq_restore(flags
);
3700 mutex_unlock(&slab_mutex
);
3708 static struct notifier_block slab_notifier
= {
3709 .notifier_call
= slab_cpuup_callback
3714 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
3716 struct kmem_cache
*s
;
3719 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3720 return kmalloc_large(size
, gfpflags
);
3722 s
= kmalloc_slab(size
, gfpflags
);
3724 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3727 ret
= slab_alloc(s
, gfpflags
, caller
);
3729 /* Honor the call site pointer we received. */
3730 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
3736 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3737 int node
, unsigned long caller
)
3739 struct kmem_cache
*s
;
3742 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3743 ret
= kmalloc_large_node(size
, gfpflags
, node
);
3745 trace_kmalloc_node(caller
, ret
,
3746 size
, PAGE_SIZE
<< get_order(size
),
3752 s
= kmalloc_slab(size
, gfpflags
);
3754 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3757 ret
= slab_alloc_node(s
, gfpflags
, node
, caller
);
3759 /* Honor the call site pointer we received. */
3760 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
3767 static int count_inuse(struct page
*page
)
3772 static int count_total(struct page
*page
)
3774 return page
->objects
;
3778 #ifdef CONFIG_SLUB_DEBUG
3779 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3783 void *addr
= page_address(page
);
3785 if (!check_slab(s
, page
) ||
3786 !on_freelist(s
, page
, NULL
))
3789 /* Now we know that a valid freelist exists */
3790 bitmap_zero(map
, page
->objects
);
3792 get_map(s
, page
, map
);
3793 for_each_object(p
, s
, addr
, page
->objects
) {
3794 if (test_bit(slab_index(p
, s
, addr
), map
))
3795 if (!check_object(s
, page
, p
, SLUB_RED_INACTIVE
))
3799 for_each_object(p
, s
, addr
, page
->objects
)
3800 if (!test_bit(slab_index(p
, s
, addr
), map
))
3801 if (!check_object(s
, page
, p
, SLUB_RED_ACTIVE
))
3806 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
3810 validate_slab(s
, page
, map
);
3814 static int validate_slab_node(struct kmem_cache
*s
,
3815 struct kmem_cache_node
*n
, unsigned long *map
)
3817 unsigned long count
= 0;
3819 unsigned long flags
;
3821 spin_lock_irqsave(&n
->list_lock
, flags
);
3823 list_for_each_entry(page
, &n
->partial
, lru
) {
3824 validate_slab_slab(s
, page
, map
);
3827 if (count
!= n
->nr_partial
)
3828 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
3829 s
->name
, count
, n
->nr_partial
);
3831 if (!(s
->flags
& SLAB_STORE_USER
))
3834 list_for_each_entry(page
, &n
->full
, lru
) {
3835 validate_slab_slab(s
, page
, map
);
3838 if (count
!= atomic_long_read(&n
->nr_slabs
))
3839 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
3840 s
->name
, count
, atomic_long_read(&n
->nr_slabs
));
3843 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3847 static long validate_slab_cache(struct kmem_cache
*s
)
3850 unsigned long count
= 0;
3851 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
3852 sizeof(unsigned long), GFP_KERNEL
);
3853 struct kmem_cache_node
*n
;
3859 for_each_kmem_cache_node(s
, node
, n
)
3860 count
+= validate_slab_node(s
, n
, map
);
3865 * Generate lists of code addresses where slabcache objects are allocated
3870 unsigned long count
;
3877 DECLARE_BITMAP(cpus
, NR_CPUS
);
3883 unsigned long count
;
3884 struct location
*loc
;
3887 static void free_loc_track(struct loc_track
*t
)
3890 free_pages((unsigned long)t
->loc
,
3891 get_order(sizeof(struct location
) * t
->max
));
3894 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
3899 order
= get_order(sizeof(struct location
) * max
);
3901 l
= (void *)__get_free_pages(flags
, order
);
3906 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
3914 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
3915 const struct track
*track
)
3917 long start
, end
, pos
;
3919 unsigned long caddr
;
3920 unsigned long age
= jiffies
- track
->when
;
3926 pos
= start
+ (end
- start
+ 1) / 2;
3929 * There is nothing at "end". If we end up there
3930 * we need to add something to before end.
3935 caddr
= t
->loc
[pos
].addr
;
3936 if (track
->addr
== caddr
) {
3942 if (age
< l
->min_time
)
3944 if (age
> l
->max_time
)
3947 if (track
->pid
< l
->min_pid
)
3948 l
->min_pid
= track
->pid
;
3949 if (track
->pid
> l
->max_pid
)
3950 l
->max_pid
= track
->pid
;
3952 cpumask_set_cpu(track
->cpu
,
3953 to_cpumask(l
->cpus
));
3955 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3959 if (track
->addr
< caddr
)
3966 * Not found. Insert new tracking element.
3968 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
3974 (t
->count
- pos
) * sizeof(struct location
));
3977 l
->addr
= track
->addr
;
3981 l
->min_pid
= track
->pid
;
3982 l
->max_pid
= track
->pid
;
3983 cpumask_clear(to_cpumask(l
->cpus
));
3984 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
3985 nodes_clear(l
->nodes
);
3986 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3990 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
3991 struct page
*page
, enum track_item alloc
,
3994 void *addr
= page_address(page
);
3997 bitmap_zero(map
, page
->objects
);
3998 get_map(s
, page
, map
);
4000 for_each_object(p
, s
, addr
, page
->objects
)
4001 if (!test_bit(slab_index(p
, s
, addr
), map
))
4002 add_location(t
, s
, get_track(s
, p
, alloc
));
4005 static int list_locations(struct kmem_cache
*s
, char *buf
,
4006 enum track_item alloc
)
4010 struct loc_track t
= { 0, 0, NULL
};
4012 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4013 sizeof(unsigned long), GFP_KERNEL
);
4014 struct kmem_cache_node
*n
;
4016 if (!map
|| !alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
4019 return sprintf(buf
, "Out of memory\n");
4021 /* Push back cpu slabs */
4024 for_each_kmem_cache_node(s
, node
, n
) {
4025 unsigned long flags
;
4028 if (!atomic_long_read(&n
->nr_slabs
))
4031 spin_lock_irqsave(&n
->list_lock
, flags
);
4032 list_for_each_entry(page
, &n
->partial
, lru
)
4033 process_slab(&t
, s
, page
, alloc
, map
);
4034 list_for_each_entry(page
, &n
->full
, lru
)
4035 process_slab(&t
, s
, page
, alloc
, map
);
4036 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4039 for (i
= 0; i
< t
.count
; i
++) {
4040 struct location
*l
= &t
.loc
[i
];
4042 if (len
> PAGE_SIZE
- KSYM_SYMBOL_LEN
- 100)
4044 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
4047 len
+= sprintf(buf
+ len
, "%pS", (void *)l
->addr
);
4049 len
+= sprintf(buf
+ len
, "<not-available>");
4051 if (l
->sum_time
!= l
->min_time
) {
4052 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
4054 (long)div_u64(l
->sum_time
, l
->count
),
4057 len
+= sprintf(buf
+ len
, " age=%ld",
4060 if (l
->min_pid
!= l
->max_pid
)
4061 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
4062 l
->min_pid
, l
->max_pid
);
4064 len
+= sprintf(buf
+ len
, " pid=%ld",
4067 if (num_online_cpus() > 1 &&
4068 !cpumask_empty(to_cpumask(l
->cpus
)) &&
4069 len
< PAGE_SIZE
- 60) {
4070 len
+= sprintf(buf
+ len
, " cpus=");
4071 len
+= cpulist_scnprintf(buf
+ len
,
4072 PAGE_SIZE
- len
- 50,
4073 to_cpumask(l
->cpus
));
4076 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
) &&
4077 len
< PAGE_SIZE
- 60) {
4078 len
+= sprintf(buf
+ len
, " nodes=");
4079 len
+= nodelist_scnprintf(buf
+ len
,
4080 PAGE_SIZE
- len
- 50,
4084 len
+= sprintf(buf
+ len
, "\n");
4090 len
+= sprintf(buf
, "No data\n");
4095 #ifdef SLUB_RESILIENCY_TEST
4096 static void __init
resiliency_test(void)
4100 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 16 || KMALLOC_SHIFT_HIGH
< 10);
4102 pr_err("SLUB resiliency testing\n");
4103 pr_err("-----------------------\n");
4104 pr_err("A. Corruption after allocation\n");
4106 p
= kzalloc(16, GFP_KERNEL
);
4108 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4111 validate_slab_cache(kmalloc_caches
[4]);
4113 /* Hmmm... The next two are dangerous */
4114 p
= kzalloc(32, GFP_KERNEL
);
4115 p
[32 + sizeof(void *)] = 0x34;
4116 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4118 pr_err("If allocated object is overwritten then not detectable\n\n");
4120 validate_slab_cache(kmalloc_caches
[5]);
4121 p
= kzalloc(64, GFP_KERNEL
);
4122 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
4124 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4126 pr_err("If allocated object is overwritten then not detectable\n\n");
4127 validate_slab_cache(kmalloc_caches
[6]);
4129 pr_err("\nB. Corruption after free\n");
4130 p
= kzalloc(128, GFP_KERNEL
);
4133 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
4134 validate_slab_cache(kmalloc_caches
[7]);
4136 p
= kzalloc(256, GFP_KERNEL
);
4139 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
4140 validate_slab_cache(kmalloc_caches
[8]);
4142 p
= kzalloc(512, GFP_KERNEL
);
4145 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
4146 validate_slab_cache(kmalloc_caches
[9]);
4150 static void resiliency_test(void) {};
4155 enum slab_stat_type
{
4156 SL_ALL
, /* All slabs */
4157 SL_PARTIAL
, /* Only partially allocated slabs */
4158 SL_CPU
, /* Only slabs used for cpu caches */
4159 SL_OBJECTS
, /* Determine allocated objects not slabs */
4160 SL_TOTAL
/* Determine object capacity not slabs */
4163 #define SO_ALL (1 << SL_ALL)
4164 #define SO_PARTIAL (1 << SL_PARTIAL)
4165 #define SO_CPU (1 << SL_CPU)
4166 #define SO_OBJECTS (1 << SL_OBJECTS)
4167 #define SO_TOTAL (1 << SL_TOTAL)
4169 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
4170 char *buf
, unsigned long flags
)
4172 unsigned long total
= 0;
4175 unsigned long *nodes
;
4177 nodes
= kzalloc(sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
4181 if (flags
& SO_CPU
) {
4184 for_each_possible_cpu(cpu
) {
4185 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
,
4190 page
= ACCESS_ONCE(c
->page
);
4194 node
= page_to_nid(page
);
4195 if (flags
& SO_TOTAL
)
4197 else if (flags
& SO_OBJECTS
)
4205 page
= ACCESS_ONCE(c
->partial
);
4207 node
= page_to_nid(page
);
4208 if (flags
& SO_TOTAL
)
4210 else if (flags
& SO_OBJECTS
)
4221 #ifdef CONFIG_SLUB_DEBUG
4222 if (flags
& SO_ALL
) {
4223 struct kmem_cache_node
*n
;
4225 for_each_kmem_cache_node(s
, node
, n
) {
4227 if (flags
& SO_TOTAL
)
4228 x
= atomic_long_read(&n
->total_objects
);
4229 else if (flags
& SO_OBJECTS
)
4230 x
= atomic_long_read(&n
->total_objects
) -
4231 count_partial(n
, count_free
);
4233 x
= atomic_long_read(&n
->nr_slabs
);
4240 if (flags
& SO_PARTIAL
) {
4241 struct kmem_cache_node
*n
;
4243 for_each_kmem_cache_node(s
, node
, n
) {
4244 if (flags
& SO_TOTAL
)
4245 x
= count_partial(n
, count_total
);
4246 else if (flags
& SO_OBJECTS
)
4247 x
= count_partial(n
, count_inuse
);
4254 x
= sprintf(buf
, "%lu", total
);
4256 for (node
= 0; node
< nr_node_ids
; node
++)
4258 x
+= sprintf(buf
+ x
, " N%d=%lu",
4263 return x
+ sprintf(buf
+ x
, "\n");
4266 #ifdef CONFIG_SLUB_DEBUG
4267 static int any_slab_objects(struct kmem_cache
*s
)
4270 struct kmem_cache_node
*n
;
4272 for_each_kmem_cache_node(s
, node
, n
)
4273 if (atomic_long_read(&n
->total_objects
))
4280 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4281 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4283 struct slab_attribute
{
4284 struct attribute attr
;
4285 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
4286 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
4289 #define SLAB_ATTR_RO(_name) \
4290 static struct slab_attribute _name##_attr = \
4291 __ATTR(_name, 0400, _name##_show, NULL)
4293 #define SLAB_ATTR(_name) \
4294 static struct slab_attribute _name##_attr = \
4295 __ATTR(_name, 0600, _name##_show, _name##_store)
4297 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
4299 return sprintf(buf
, "%d\n", s
->size
);
4301 SLAB_ATTR_RO(slab_size
);
4303 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
4305 return sprintf(buf
, "%d\n", s
->align
);
4307 SLAB_ATTR_RO(align
);
4309 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
4311 return sprintf(buf
, "%d\n", s
->object_size
);
4313 SLAB_ATTR_RO(object_size
);
4315 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
4317 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
4319 SLAB_ATTR_RO(objs_per_slab
);
4321 static ssize_t
order_store(struct kmem_cache
*s
,
4322 const char *buf
, size_t length
)
4324 unsigned long order
;
4327 err
= kstrtoul(buf
, 10, &order
);
4331 if (order
> slub_max_order
|| order
< slub_min_order
)
4334 calculate_sizes(s
, order
);
4338 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
4340 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
4344 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
4346 return sprintf(buf
, "%lu\n", s
->min_partial
);
4349 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
4355 err
= kstrtoul(buf
, 10, &min
);
4359 set_min_partial(s
, min
);
4362 SLAB_ATTR(min_partial
);
4364 static ssize_t
cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4366 return sprintf(buf
, "%u\n", s
->cpu_partial
);
4369 static ssize_t
cpu_partial_store(struct kmem_cache
*s
, const char *buf
,
4372 unsigned long objects
;
4375 err
= kstrtoul(buf
, 10, &objects
);
4378 if (objects
&& !kmem_cache_has_cpu_partial(s
))
4381 s
->cpu_partial
= objects
;
4385 SLAB_ATTR(cpu_partial
);
4387 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
4391 return sprintf(buf
, "%pS\n", s
->ctor
);
4395 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
4397 return sprintf(buf
, "%d\n", s
->refcount
< 0 ? 0 : s
->refcount
- 1);
4399 SLAB_ATTR_RO(aliases
);
4401 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
4403 return show_slab_objects(s
, buf
, SO_PARTIAL
);
4405 SLAB_ATTR_RO(partial
);
4407 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
4409 return show_slab_objects(s
, buf
, SO_CPU
);
4411 SLAB_ATTR_RO(cpu_slabs
);
4413 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
4415 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
4417 SLAB_ATTR_RO(objects
);
4419 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
4421 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
4423 SLAB_ATTR_RO(objects_partial
);
4425 static ssize_t
slabs_cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4432 for_each_online_cpu(cpu
) {
4433 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
)->partial
;
4436 pages
+= page
->pages
;
4437 objects
+= page
->pobjects
;
4441 len
= sprintf(buf
, "%d(%d)", objects
, pages
);
4444 for_each_online_cpu(cpu
) {
4445 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
) ->partial
;
4447 if (page
&& len
< PAGE_SIZE
- 20)
4448 len
+= sprintf(buf
+ len
, " C%d=%d(%d)", cpu
,
4449 page
->pobjects
, page
->pages
);
4452 return len
+ sprintf(buf
+ len
, "\n");
4454 SLAB_ATTR_RO(slabs_cpu_partial
);
4456 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
4458 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
4461 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
4462 const char *buf
, size_t length
)
4464 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
4466 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
4469 SLAB_ATTR(reclaim_account
);
4471 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
4473 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
4475 SLAB_ATTR_RO(hwcache_align
);
4477 #ifdef CONFIG_ZONE_DMA
4478 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
4480 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
4482 SLAB_ATTR_RO(cache_dma
);
4485 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
4487 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
4489 SLAB_ATTR_RO(destroy_by_rcu
);
4491 static ssize_t
reserved_show(struct kmem_cache
*s
, char *buf
)
4493 return sprintf(buf
, "%d\n", s
->reserved
);
4495 SLAB_ATTR_RO(reserved
);
4497 #ifdef CONFIG_SLUB_DEBUG
4498 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
4500 return show_slab_objects(s
, buf
, SO_ALL
);
4502 SLAB_ATTR_RO(slabs
);
4504 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
4506 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
4508 SLAB_ATTR_RO(total_objects
);
4510 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
4512 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
4515 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
4516 const char *buf
, size_t length
)
4518 s
->flags
&= ~SLAB_DEBUG_FREE
;
4519 if (buf
[0] == '1') {
4520 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4521 s
->flags
|= SLAB_DEBUG_FREE
;
4525 SLAB_ATTR(sanity_checks
);
4527 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
4529 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
4532 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
4536 * Tracing a merged cache is going to give confusing results
4537 * as well as cause other issues like converting a mergeable
4538 * cache into an umergeable one.
4540 if (s
->refcount
> 1)
4543 s
->flags
&= ~SLAB_TRACE
;
4544 if (buf
[0] == '1') {
4545 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4546 s
->flags
|= SLAB_TRACE
;
4552 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
4554 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
4557 static ssize_t
red_zone_store(struct kmem_cache
*s
,
4558 const char *buf
, size_t length
)
4560 if (any_slab_objects(s
))
4563 s
->flags
&= ~SLAB_RED_ZONE
;
4564 if (buf
[0] == '1') {
4565 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4566 s
->flags
|= SLAB_RED_ZONE
;
4568 calculate_sizes(s
, -1);
4571 SLAB_ATTR(red_zone
);
4573 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
4575 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
4578 static ssize_t
poison_store(struct kmem_cache
*s
,
4579 const char *buf
, size_t length
)
4581 if (any_slab_objects(s
))
4584 s
->flags
&= ~SLAB_POISON
;
4585 if (buf
[0] == '1') {
4586 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4587 s
->flags
|= SLAB_POISON
;
4589 calculate_sizes(s
, -1);
4594 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
4596 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
4599 static ssize_t
store_user_store(struct kmem_cache
*s
,
4600 const char *buf
, size_t length
)
4602 if (any_slab_objects(s
))
4605 s
->flags
&= ~SLAB_STORE_USER
;
4606 if (buf
[0] == '1') {
4607 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4608 s
->flags
|= SLAB_STORE_USER
;
4610 calculate_sizes(s
, -1);
4613 SLAB_ATTR(store_user
);
4615 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4620 static ssize_t
validate_store(struct kmem_cache
*s
,
4621 const char *buf
, size_t length
)
4625 if (buf
[0] == '1') {
4626 ret
= validate_slab_cache(s
);
4632 SLAB_ATTR(validate
);
4634 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4636 if (!(s
->flags
& SLAB_STORE_USER
))
4638 return list_locations(s
, buf
, TRACK_ALLOC
);
4640 SLAB_ATTR_RO(alloc_calls
);
4642 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4644 if (!(s
->flags
& SLAB_STORE_USER
))
4646 return list_locations(s
, buf
, TRACK_FREE
);
4648 SLAB_ATTR_RO(free_calls
);
4649 #endif /* CONFIG_SLUB_DEBUG */
4651 #ifdef CONFIG_FAILSLAB
4652 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
4654 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
4657 static ssize_t
failslab_store(struct kmem_cache
*s
, const char *buf
,
4660 if (s
->refcount
> 1)
4663 s
->flags
&= ~SLAB_FAILSLAB
;
4665 s
->flags
|= SLAB_FAILSLAB
;
4668 SLAB_ATTR(failslab
);
4671 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4676 static ssize_t
shrink_store(struct kmem_cache
*s
,
4677 const char *buf
, size_t length
)
4679 if (buf
[0] == '1') {
4680 int rc
= kmem_cache_shrink(s
);
4691 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4693 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4696 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4697 const char *buf
, size_t length
)
4699 unsigned long ratio
;
4702 err
= kstrtoul(buf
, 10, &ratio
);
4707 s
->remote_node_defrag_ratio
= ratio
* 10;
4711 SLAB_ATTR(remote_node_defrag_ratio
);
4714 #ifdef CONFIG_SLUB_STATS
4715 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
4717 unsigned long sum
= 0;
4720 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
4725 for_each_online_cpu(cpu
) {
4726 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
4732 len
= sprintf(buf
, "%lu", sum
);
4735 for_each_online_cpu(cpu
) {
4736 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
4737 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
4741 return len
+ sprintf(buf
+ len
, "\n");
4744 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
4748 for_each_online_cpu(cpu
)
4749 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
4752 #define STAT_ATTR(si, text) \
4753 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4755 return show_stat(s, buf, si); \
4757 static ssize_t text##_store(struct kmem_cache *s, \
4758 const char *buf, size_t length) \
4760 if (buf[0] != '0') \
4762 clear_stat(s, si); \
4767 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4768 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
4769 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
4770 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
4771 STAT_ATTR(FREE_FROZEN
, free_frozen
);
4772 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
4773 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
4774 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
4775 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
4776 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
4777 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
4778 STAT_ATTR(FREE_SLAB
, free_slab
);
4779 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
4780 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
4781 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
4782 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4783 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4784 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4785 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
4786 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
4787 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
4788 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
4789 STAT_ATTR(CPU_PARTIAL_ALLOC
, cpu_partial_alloc
);
4790 STAT_ATTR(CPU_PARTIAL_FREE
, cpu_partial_free
);
4791 STAT_ATTR(CPU_PARTIAL_NODE
, cpu_partial_node
);
4792 STAT_ATTR(CPU_PARTIAL_DRAIN
, cpu_partial_drain
);
4795 static struct attribute
*slab_attrs
[] = {
4796 &slab_size_attr
.attr
,
4797 &object_size_attr
.attr
,
4798 &objs_per_slab_attr
.attr
,
4800 &min_partial_attr
.attr
,
4801 &cpu_partial_attr
.attr
,
4803 &objects_partial_attr
.attr
,
4805 &cpu_slabs_attr
.attr
,
4809 &hwcache_align_attr
.attr
,
4810 &reclaim_account_attr
.attr
,
4811 &destroy_by_rcu_attr
.attr
,
4813 &reserved_attr
.attr
,
4814 &slabs_cpu_partial_attr
.attr
,
4815 #ifdef CONFIG_SLUB_DEBUG
4816 &total_objects_attr
.attr
,
4818 &sanity_checks_attr
.attr
,
4820 &red_zone_attr
.attr
,
4822 &store_user_attr
.attr
,
4823 &validate_attr
.attr
,
4824 &alloc_calls_attr
.attr
,
4825 &free_calls_attr
.attr
,
4827 #ifdef CONFIG_ZONE_DMA
4828 &cache_dma_attr
.attr
,
4831 &remote_node_defrag_ratio_attr
.attr
,
4833 #ifdef CONFIG_SLUB_STATS
4834 &alloc_fastpath_attr
.attr
,
4835 &alloc_slowpath_attr
.attr
,
4836 &free_fastpath_attr
.attr
,
4837 &free_slowpath_attr
.attr
,
4838 &free_frozen_attr
.attr
,
4839 &free_add_partial_attr
.attr
,
4840 &free_remove_partial_attr
.attr
,
4841 &alloc_from_partial_attr
.attr
,
4842 &alloc_slab_attr
.attr
,
4843 &alloc_refill_attr
.attr
,
4844 &alloc_node_mismatch_attr
.attr
,
4845 &free_slab_attr
.attr
,
4846 &cpuslab_flush_attr
.attr
,
4847 &deactivate_full_attr
.attr
,
4848 &deactivate_empty_attr
.attr
,
4849 &deactivate_to_head_attr
.attr
,
4850 &deactivate_to_tail_attr
.attr
,
4851 &deactivate_remote_frees_attr
.attr
,
4852 &deactivate_bypass_attr
.attr
,
4853 &order_fallback_attr
.attr
,
4854 &cmpxchg_double_fail_attr
.attr
,
4855 &cmpxchg_double_cpu_fail_attr
.attr
,
4856 &cpu_partial_alloc_attr
.attr
,
4857 &cpu_partial_free_attr
.attr
,
4858 &cpu_partial_node_attr
.attr
,
4859 &cpu_partial_drain_attr
.attr
,
4861 #ifdef CONFIG_FAILSLAB
4862 &failslab_attr
.attr
,
4868 static struct attribute_group slab_attr_group
= {
4869 .attrs
= slab_attrs
,
4872 static ssize_t
slab_attr_show(struct kobject
*kobj
,
4873 struct attribute
*attr
,
4876 struct slab_attribute
*attribute
;
4877 struct kmem_cache
*s
;
4880 attribute
= to_slab_attr(attr
);
4883 if (!attribute
->show
)
4886 err
= attribute
->show(s
, buf
);
4891 static ssize_t
slab_attr_store(struct kobject
*kobj
,
4892 struct attribute
*attr
,
4893 const char *buf
, size_t len
)
4895 struct slab_attribute
*attribute
;
4896 struct kmem_cache
*s
;
4899 attribute
= to_slab_attr(attr
);
4902 if (!attribute
->store
)
4905 err
= attribute
->store(s
, buf
, len
);
4906 #ifdef CONFIG_MEMCG_KMEM
4907 if (slab_state
>= FULL
&& err
>= 0 && is_root_cache(s
)) {
4910 mutex_lock(&slab_mutex
);
4911 if (s
->max_attr_size
< len
)
4912 s
->max_attr_size
= len
;
4915 * This is a best effort propagation, so this function's return
4916 * value will be determined by the parent cache only. This is
4917 * basically because not all attributes will have a well
4918 * defined semantics for rollbacks - most of the actions will
4919 * have permanent effects.
4921 * Returning the error value of any of the children that fail
4922 * is not 100 % defined, in the sense that users seeing the
4923 * error code won't be able to know anything about the state of
4926 * Only returning the error code for the parent cache at least
4927 * has well defined semantics. The cache being written to
4928 * directly either failed or succeeded, in which case we loop
4929 * through the descendants with best-effort propagation.
4931 for_each_memcg_cache_index(i
) {
4932 struct kmem_cache
*c
= cache_from_memcg_idx(s
, i
);
4934 attribute
->store(c
, buf
, len
);
4936 mutex_unlock(&slab_mutex
);
4942 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
)
4944 #ifdef CONFIG_MEMCG_KMEM
4946 char *buffer
= NULL
;
4947 struct kmem_cache
*root_cache
;
4949 if (is_root_cache(s
))
4952 root_cache
= s
->memcg_params
->root_cache
;
4955 * This mean this cache had no attribute written. Therefore, no point
4956 * in copying default values around
4958 if (!root_cache
->max_attr_size
)
4961 for (i
= 0; i
< ARRAY_SIZE(slab_attrs
); i
++) {
4964 struct slab_attribute
*attr
= to_slab_attr(slab_attrs
[i
]);
4966 if (!attr
|| !attr
->store
|| !attr
->show
)
4970 * It is really bad that we have to allocate here, so we will
4971 * do it only as a fallback. If we actually allocate, though,
4972 * we can just use the allocated buffer until the end.
4974 * Most of the slub attributes will tend to be very small in
4975 * size, but sysfs allows buffers up to a page, so they can
4976 * theoretically happen.
4980 else if (root_cache
->max_attr_size
< ARRAY_SIZE(mbuf
))
4983 buffer
= (char *) get_zeroed_page(GFP_KERNEL
);
4984 if (WARN_ON(!buffer
))
4989 attr
->show(root_cache
, buf
);
4990 attr
->store(s
, buf
, strlen(buf
));
4994 free_page((unsigned long)buffer
);
4998 static void kmem_cache_release(struct kobject
*k
)
5000 slab_kmem_cache_release(to_slab(k
));
5003 static const struct sysfs_ops slab_sysfs_ops
= {
5004 .show
= slab_attr_show
,
5005 .store
= slab_attr_store
,
5008 static struct kobj_type slab_ktype
= {
5009 .sysfs_ops
= &slab_sysfs_ops
,
5010 .release
= kmem_cache_release
,
5013 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
5015 struct kobj_type
*ktype
= get_ktype(kobj
);
5017 if (ktype
== &slab_ktype
)
5022 static const struct kset_uevent_ops slab_uevent_ops
= {
5023 .filter
= uevent_filter
,
5026 static struct kset
*slab_kset
;
5028 static inline struct kset
*cache_kset(struct kmem_cache
*s
)
5030 #ifdef CONFIG_MEMCG_KMEM
5031 if (!is_root_cache(s
))
5032 return s
->memcg_params
->root_cache
->memcg_kset
;
5037 #define ID_STR_LENGTH 64
5039 /* Create a unique string id for a slab cache:
5041 * Format :[flags-]size
5043 static char *create_unique_id(struct kmem_cache
*s
)
5045 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
5052 * First flags affecting slabcache operations. We will only
5053 * get here for aliasable slabs so we do not need to support
5054 * too many flags. The flags here must cover all flags that
5055 * are matched during merging to guarantee that the id is
5058 if (s
->flags
& SLAB_CACHE_DMA
)
5060 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
5062 if (s
->flags
& SLAB_DEBUG_FREE
)
5064 if (!(s
->flags
& SLAB_NOTRACK
))
5068 p
+= sprintf(p
, "%07d", s
->size
);
5070 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
5074 static int sysfs_slab_add(struct kmem_cache
*s
)
5078 int unmergeable
= slab_unmergeable(s
);
5082 * Slabcache can never be merged so we can use the name proper.
5083 * This is typically the case for debug situations. In that
5084 * case we can catch duplicate names easily.
5086 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
5090 * Create a unique name for the slab as a target
5093 name
= create_unique_id(s
);
5096 s
->kobj
.kset
= cache_kset(s
);
5097 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, "%s", name
);
5101 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
5105 #ifdef CONFIG_MEMCG_KMEM
5106 if (is_root_cache(s
)) {
5107 s
->memcg_kset
= kset_create_and_add("cgroup", NULL
, &s
->kobj
);
5108 if (!s
->memcg_kset
) {
5115 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
5117 /* Setup first alias */
5118 sysfs_slab_alias(s
, s
->name
);
5125 kobject_del(&s
->kobj
);
5127 kobject_put(&s
->kobj
);
5131 void sysfs_slab_remove(struct kmem_cache
*s
)
5133 if (slab_state
< FULL
)
5135 * Sysfs has not been setup yet so no need to remove the
5140 #ifdef CONFIG_MEMCG_KMEM
5141 kset_unregister(s
->memcg_kset
);
5143 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
5144 kobject_del(&s
->kobj
);
5145 kobject_put(&s
->kobj
);
5149 * Need to buffer aliases during bootup until sysfs becomes
5150 * available lest we lose that information.
5152 struct saved_alias
{
5153 struct kmem_cache
*s
;
5155 struct saved_alias
*next
;
5158 static struct saved_alias
*alias_list
;
5160 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5162 struct saved_alias
*al
;
5164 if (slab_state
== FULL
) {
5166 * If we have a leftover link then remove it.
5168 sysfs_remove_link(&slab_kset
->kobj
, name
);
5169 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5172 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5178 al
->next
= alias_list
;
5183 static int __init
slab_sysfs_init(void)
5185 struct kmem_cache
*s
;
5188 mutex_lock(&slab_mutex
);
5190 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
5192 mutex_unlock(&slab_mutex
);
5193 pr_err("Cannot register slab subsystem.\n");
5199 list_for_each_entry(s
, &slab_caches
, list
) {
5200 err
= sysfs_slab_add(s
);
5202 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5206 while (alias_list
) {
5207 struct saved_alias
*al
= alias_list
;
5209 alias_list
= alias_list
->next
;
5210 err
= sysfs_slab_alias(al
->s
, al
->name
);
5212 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5217 mutex_unlock(&slab_mutex
);
5222 __initcall(slab_sysfs_init
);
5223 #endif /* CONFIG_SYSFS */
5226 * The /proc/slabinfo ABI
5228 #ifdef CONFIG_SLABINFO
5229 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
)
5231 unsigned long nr_slabs
= 0;
5232 unsigned long nr_objs
= 0;
5233 unsigned long nr_free
= 0;
5235 struct kmem_cache_node
*n
;
5237 for_each_kmem_cache_node(s
, node
, n
) {
5238 nr_slabs
+= node_nr_slabs(n
);
5239 nr_objs
+= node_nr_objs(n
);
5240 nr_free
+= count_partial(n
, count_free
);
5243 sinfo
->active_objs
= nr_objs
- nr_free
;
5244 sinfo
->num_objs
= nr_objs
;
5245 sinfo
->active_slabs
= nr_slabs
;
5246 sinfo
->num_slabs
= nr_slabs
;
5247 sinfo
->objects_per_slab
= oo_objects(s
->oo
);
5248 sinfo
->cache_order
= oo_order(s
->oo
);
5251 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
)
5255 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
5256 size_t count
, loff_t
*ppos
)
5260 #endif /* CONFIG_SLABINFO */