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 * Set of flags that will prevent slab merging
175 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
176 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
179 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
180 SLAB_CACHE_DMA | SLAB_NOTRACK)
183 #define OO_MASK ((1 << OO_SHIFT) - 1)
184 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
186 /* Internal SLUB flags */
187 #define __OBJECT_POISON 0x80000000UL /* Poison object */
188 #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
191 static struct notifier_block slab_notifier
;
195 * Tracking user of a slab.
197 #define TRACK_ADDRS_COUNT 16
199 unsigned long addr
; /* Called from address */
200 #ifdef CONFIG_STACKTRACE
201 unsigned long addrs
[TRACK_ADDRS_COUNT
]; /* Called from address */
203 int cpu
; /* Was running on cpu */
204 int pid
; /* Pid context */
205 unsigned long when
; /* When did the operation occur */
208 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
211 static int sysfs_slab_add(struct kmem_cache
*);
212 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
213 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
);
215 static inline int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
216 static inline int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
)
218 static inline void memcg_propagate_slab_attrs(struct kmem_cache
*s
) { }
221 static inline void stat(const struct kmem_cache
*s
, enum stat_item si
)
223 #ifdef CONFIG_SLUB_STATS
225 * The rmw is racy on a preemptible kernel but this is acceptable, so
226 * avoid this_cpu_add()'s irq-disable overhead.
228 raw_cpu_inc(s
->cpu_slab
->stat
[si
]);
232 /********************************************************************
233 * Core slab cache functions
234 *******************************************************************/
236 /* Verify that a pointer has an address that is valid within a slab page */
237 static inline int check_valid_pointer(struct kmem_cache
*s
,
238 struct page
*page
, const void *object
)
245 base
= page_address(page
);
246 if (object
< base
|| object
>= base
+ page
->objects
* s
->size
||
247 (object
- base
) % s
->size
) {
254 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
256 return *(void **)(object
+ s
->offset
);
259 static void prefetch_freepointer(const struct kmem_cache
*s
, void *object
)
261 prefetch(object
+ s
->offset
);
264 static inline void *get_freepointer_safe(struct kmem_cache
*s
, void *object
)
268 #ifdef CONFIG_DEBUG_PAGEALLOC
269 probe_kernel_read(&p
, (void **)(object
+ s
->offset
), sizeof(p
));
271 p
= get_freepointer(s
, object
);
276 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
278 *(void **)(object
+ s
->offset
) = fp
;
281 /* Loop over all objects in a slab */
282 #define for_each_object(__p, __s, __addr, __objects) \
283 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
286 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
287 for (__p = (__addr), __idx = 1; __idx <= __objects;\
288 __p += (__s)->size, __idx++)
290 /* Determine object index from a given position */
291 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
293 return (p
- addr
) / s
->size
;
296 static inline size_t slab_ksize(const struct kmem_cache
*s
)
298 #ifdef CONFIG_SLUB_DEBUG
300 * Debugging requires use of the padding between object
301 * and whatever may come after it.
303 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
304 return s
->object_size
;
308 * If we have the need to store the freelist pointer
309 * back there or track user information then we can
310 * only use the space before that information.
312 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
315 * Else we can use all the padding etc for the allocation
320 static inline int order_objects(int order
, unsigned long size
, int reserved
)
322 return ((PAGE_SIZE
<< order
) - reserved
) / size
;
325 static inline struct kmem_cache_order_objects
oo_make(int order
,
326 unsigned long size
, int reserved
)
328 struct kmem_cache_order_objects x
= {
329 (order
<< OO_SHIFT
) + order_objects(order
, size
, reserved
)
335 static inline int oo_order(struct kmem_cache_order_objects x
)
337 return x
.x
>> OO_SHIFT
;
340 static inline int oo_objects(struct kmem_cache_order_objects x
)
342 return x
.x
& OO_MASK
;
346 * Per slab locking using the pagelock
348 static __always_inline
void slab_lock(struct page
*page
)
350 bit_spin_lock(PG_locked
, &page
->flags
);
353 static __always_inline
void slab_unlock(struct page
*page
)
355 __bit_spin_unlock(PG_locked
, &page
->flags
);
358 static inline void set_page_slub_counters(struct page
*page
, unsigned long counters_new
)
361 tmp
.counters
= counters_new
;
363 * page->counters can cover frozen/inuse/objects as well
364 * as page->_count. If we assign to ->counters directly
365 * we run the risk of losing updates to page->_count, so
366 * be careful and only assign to the fields we need.
368 page
->frozen
= tmp
.frozen
;
369 page
->inuse
= tmp
.inuse
;
370 page
->objects
= tmp
.objects
;
373 /* Interrupts must be disabled (for the fallback code to work right) */
374 static inline bool __cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
375 void *freelist_old
, unsigned long counters_old
,
376 void *freelist_new
, unsigned long counters_new
,
379 VM_BUG_ON(!irqs_disabled());
380 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
381 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
382 if (s
->flags
& __CMPXCHG_DOUBLE
) {
383 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
384 freelist_old
, counters_old
,
385 freelist_new
, counters_new
))
391 if (page
->freelist
== freelist_old
&&
392 page
->counters
== counters_old
) {
393 page
->freelist
= freelist_new
;
394 set_page_slub_counters(page
, counters_new
);
402 stat(s
, CMPXCHG_DOUBLE_FAIL
);
404 #ifdef SLUB_DEBUG_CMPXCHG
405 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
411 static inline bool cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
412 void *freelist_old
, unsigned long counters_old
,
413 void *freelist_new
, unsigned long counters_new
,
416 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
417 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
418 if (s
->flags
& __CMPXCHG_DOUBLE
) {
419 if (cmpxchg_double(&page
->freelist
, &page
->counters
,
420 freelist_old
, counters_old
,
421 freelist_new
, counters_new
))
428 local_irq_save(flags
);
430 if (page
->freelist
== freelist_old
&&
431 page
->counters
== counters_old
) {
432 page
->freelist
= freelist_new
;
433 set_page_slub_counters(page
, counters_new
);
435 local_irq_restore(flags
);
439 local_irq_restore(flags
);
443 stat(s
, CMPXCHG_DOUBLE_FAIL
);
445 #ifdef SLUB_DEBUG_CMPXCHG
446 pr_info("%s %s: cmpxchg double redo ", n
, s
->name
);
452 #ifdef CONFIG_SLUB_DEBUG
454 * Determine a map of object in use on a page.
456 * Node listlock must be held to guarantee that the page does
457 * not vanish from under us.
459 static void get_map(struct kmem_cache
*s
, struct page
*page
, unsigned long *map
)
462 void *addr
= page_address(page
);
464 for (p
= page
->freelist
; p
; p
= get_freepointer(s
, p
))
465 set_bit(slab_index(p
, s
, addr
), map
);
471 #ifdef CONFIG_SLUB_DEBUG_ON
472 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
474 static int slub_debug
;
477 static char *slub_debug_slabs
;
478 static int disable_higher_order_debug
;
483 static void print_section(char *text
, u8
*addr
, unsigned int length
)
485 print_hex_dump(KERN_ERR
, text
, DUMP_PREFIX_ADDRESS
, 16, 1, addr
,
489 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
490 enum track_item alloc
)
495 p
= object
+ s
->offset
+ sizeof(void *);
497 p
= object
+ s
->inuse
;
502 static void set_track(struct kmem_cache
*s
, void *object
,
503 enum track_item alloc
, unsigned long addr
)
505 struct track
*p
= get_track(s
, object
, alloc
);
508 #ifdef CONFIG_STACKTRACE
509 struct stack_trace trace
;
512 trace
.nr_entries
= 0;
513 trace
.max_entries
= TRACK_ADDRS_COUNT
;
514 trace
.entries
= p
->addrs
;
516 save_stack_trace(&trace
);
518 /* See rant in lockdep.c */
519 if (trace
.nr_entries
!= 0 &&
520 trace
.entries
[trace
.nr_entries
- 1] == ULONG_MAX
)
523 for (i
= trace
.nr_entries
; i
< TRACK_ADDRS_COUNT
; i
++)
527 p
->cpu
= smp_processor_id();
528 p
->pid
= current
->pid
;
531 memset(p
, 0, sizeof(struct track
));
534 static void init_tracking(struct kmem_cache
*s
, void *object
)
536 if (!(s
->flags
& SLAB_STORE_USER
))
539 set_track(s
, object
, TRACK_FREE
, 0UL);
540 set_track(s
, object
, TRACK_ALLOC
, 0UL);
543 static void print_track(const char *s
, struct track
*t
)
548 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
549 s
, (void *)t
->addr
, jiffies
- t
->when
, t
->cpu
, t
->pid
);
550 #ifdef CONFIG_STACKTRACE
553 for (i
= 0; i
< TRACK_ADDRS_COUNT
; i
++)
555 pr_err("\t%pS\n", (void *)t
->addrs
[i
]);
562 static void print_tracking(struct kmem_cache
*s
, void *object
)
564 if (!(s
->flags
& SLAB_STORE_USER
))
567 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
568 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
571 static void print_page_info(struct page
*page
)
573 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
574 page
, page
->objects
, page
->inuse
, page
->freelist
, page
->flags
);
578 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
580 struct va_format vaf
;
586 pr_err("=============================================================================\n");
587 pr_err("BUG %s (%s): %pV\n", s
->name
, print_tainted(), &vaf
);
588 pr_err("-----------------------------------------------------------------------------\n\n");
590 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
594 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
596 struct va_format vaf
;
602 pr_err("FIX %s: %pV\n", s
->name
, &vaf
);
606 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
608 unsigned int off
; /* Offset of last byte */
609 u8
*addr
= page_address(page
);
611 print_tracking(s
, p
);
613 print_page_info(page
);
615 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
616 p
, p
- addr
, get_freepointer(s
, p
));
619 print_section("Bytes b4 ", p
- 16, 16);
621 print_section("Object ", p
, min_t(unsigned long, s
->object_size
,
623 if (s
->flags
& SLAB_RED_ZONE
)
624 print_section("Redzone ", p
+ s
->object_size
,
625 s
->inuse
- s
->object_size
);
628 off
= s
->offset
+ sizeof(void *);
632 if (s
->flags
& SLAB_STORE_USER
)
633 off
+= 2 * sizeof(struct track
);
636 /* Beginning of the filler is the free pointer */
637 print_section("Padding ", p
+ off
, s
->size
- off
);
642 static void object_err(struct kmem_cache
*s
, struct page
*page
,
643 u8
*object
, char *reason
)
645 slab_bug(s
, "%s", reason
);
646 print_trailer(s
, page
, object
);
649 static void slab_err(struct kmem_cache
*s
, struct page
*page
,
650 const char *fmt
, ...)
656 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
658 slab_bug(s
, "%s", buf
);
659 print_page_info(page
);
663 static void init_object(struct kmem_cache
*s
, void *object
, u8 val
)
667 if (s
->flags
& __OBJECT_POISON
) {
668 memset(p
, POISON_FREE
, s
->object_size
- 1);
669 p
[s
->object_size
- 1] = POISON_END
;
672 if (s
->flags
& SLAB_RED_ZONE
)
673 memset(p
+ s
->object_size
, val
, s
->inuse
- s
->object_size
);
676 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
677 void *from
, void *to
)
679 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
680 memset(from
, data
, to
- from
);
683 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
684 u8
*object
, char *what
,
685 u8
*start
, unsigned int value
, unsigned int bytes
)
690 fault
= memchr_inv(start
, value
, bytes
);
695 while (end
> fault
&& end
[-1] == value
)
698 slab_bug(s
, "%s overwritten", what
);
699 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
700 fault
, end
- 1, fault
[0], value
);
701 print_trailer(s
, page
, object
);
703 restore_bytes(s
, what
, value
, fault
, end
);
711 * Bytes of the object to be managed.
712 * If the freepointer may overlay the object then the free
713 * pointer is the first word of the object.
715 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
718 * object + s->object_size
719 * Padding to reach word boundary. This is also used for Redzoning.
720 * Padding is extended by another word if Redzoning is enabled and
721 * object_size == inuse.
723 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
724 * 0xcc (RED_ACTIVE) for objects in use.
727 * Meta data starts here.
729 * A. Free pointer (if we cannot overwrite object on free)
730 * B. Tracking data for SLAB_STORE_USER
731 * C. Padding to reach required alignment boundary or at mininum
732 * one word if debugging is on to be able to detect writes
733 * before the word boundary.
735 * Padding is done using 0x5a (POISON_INUSE)
738 * Nothing is used beyond s->size.
740 * If slabcaches are merged then the object_size and inuse boundaries are mostly
741 * ignored. And therefore no slab options that rely on these boundaries
742 * may be used with merged slabcaches.
745 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
747 unsigned long off
= s
->inuse
; /* The end of info */
750 /* Freepointer is placed after the object. */
751 off
+= sizeof(void *);
753 if (s
->flags
& SLAB_STORE_USER
)
754 /* We also have user information there */
755 off
+= 2 * sizeof(struct track
);
760 return check_bytes_and_report(s
, page
, p
, "Object padding",
761 p
+ off
, POISON_INUSE
, s
->size
- off
);
764 /* Check the pad bytes at the end of a slab page */
765 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
773 if (!(s
->flags
& SLAB_POISON
))
776 start
= page_address(page
);
777 length
= (PAGE_SIZE
<< compound_order(page
)) - s
->reserved
;
778 end
= start
+ length
;
779 remainder
= length
% s
->size
;
783 fault
= memchr_inv(end
- remainder
, POISON_INUSE
, remainder
);
786 while (end
> fault
&& end
[-1] == POISON_INUSE
)
789 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
790 print_section("Padding ", end
- remainder
, remainder
);
792 restore_bytes(s
, "slab padding", POISON_INUSE
, end
- remainder
, end
);
796 static int check_object(struct kmem_cache
*s
, struct page
*page
,
797 void *object
, u8 val
)
800 u8
*endobject
= object
+ s
->object_size
;
802 if (s
->flags
& SLAB_RED_ZONE
) {
803 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
804 endobject
, val
, s
->inuse
- s
->object_size
))
807 if ((s
->flags
& SLAB_POISON
) && s
->object_size
< s
->inuse
) {
808 check_bytes_and_report(s
, page
, p
, "Alignment padding",
809 endobject
, POISON_INUSE
,
810 s
->inuse
- s
->object_size
);
814 if (s
->flags
& SLAB_POISON
) {
815 if (val
!= SLUB_RED_ACTIVE
&& (s
->flags
& __OBJECT_POISON
) &&
816 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
817 POISON_FREE
, s
->object_size
- 1) ||
818 !check_bytes_and_report(s
, page
, p
, "Poison",
819 p
+ s
->object_size
- 1, POISON_END
, 1)))
822 * check_pad_bytes cleans up on its own.
824 check_pad_bytes(s
, page
, p
);
827 if (!s
->offset
&& val
== SLUB_RED_ACTIVE
)
829 * Object and freepointer overlap. Cannot check
830 * freepointer while object is allocated.
834 /* Check free pointer validity */
835 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
836 object_err(s
, page
, p
, "Freepointer corrupt");
838 * No choice but to zap it and thus lose the remainder
839 * of the free objects in this slab. May cause
840 * another error because the object count is now wrong.
842 set_freepointer(s
, p
, NULL
);
848 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
852 VM_BUG_ON(!irqs_disabled());
854 if (!PageSlab(page
)) {
855 slab_err(s
, page
, "Not a valid slab page");
859 maxobj
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
860 if (page
->objects
> maxobj
) {
861 slab_err(s
, page
, "objects %u > max %u",
862 s
->name
, page
->objects
, maxobj
);
865 if (page
->inuse
> page
->objects
) {
866 slab_err(s
, page
, "inuse %u > max %u",
867 s
->name
, page
->inuse
, page
->objects
);
870 /* Slab_pad_check fixes things up after itself */
871 slab_pad_check(s
, page
);
876 * Determine if a certain object on a page is on the freelist. Must hold the
877 * slab lock to guarantee that the chains are in a consistent state.
879 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
884 unsigned long max_objects
;
887 while (fp
&& nr
<= page
->objects
) {
890 if (!check_valid_pointer(s
, page
, fp
)) {
892 object_err(s
, page
, object
,
893 "Freechain corrupt");
894 set_freepointer(s
, object
, NULL
);
896 slab_err(s
, page
, "Freepointer corrupt");
897 page
->freelist
= NULL
;
898 page
->inuse
= page
->objects
;
899 slab_fix(s
, "Freelist cleared");
905 fp
= get_freepointer(s
, object
);
909 max_objects
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
910 if (max_objects
> MAX_OBJS_PER_PAGE
)
911 max_objects
= MAX_OBJS_PER_PAGE
;
913 if (page
->objects
!= max_objects
) {
914 slab_err(s
, page
, "Wrong number of objects. Found %d but "
915 "should be %d", page
->objects
, max_objects
);
916 page
->objects
= max_objects
;
917 slab_fix(s
, "Number of objects adjusted.");
919 if (page
->inuse
!= page
->objects
- nr
) {
920 slab_err(s
, page
, "Wrong object count. Counter is %d but "
921 "counted were %d", page
->inuse
, page
->objects
- nr
);
922 page
->inuse
= page
->objects
- nr
;
923 slab_fix(s
, "Object count adjusted.");
925 return search
== NULL
;
928 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
,
931 if (s
->flags
& SLAB_TRACE
) {
932 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
934 alloc
? "alloc" : "free",
939 print_section("Object ", (void *)object
,
947 * Tracking of fully allocated slabs for debugging purposes.
949 static void add_full(struct kmem_cache
*s
,
950 struct kmem_cache_node
*n
, struct page
*page
)
952 if (!(s
->flags
& SLAB_STORE_USER
))
955 lockdep_assert_held(&n
->list_lock
);
956 list_add(&page
->lru
, &n
->full
);
959 static void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
, struct page
*page
)
961 if (!(s
->flags
& SLAB_STORE_USER
))
964 lockdep_assert_held(&n
->list_lock
);
965 list_del(&page
->lru
);
968 /* Tracking of the number of slabs for debugging purposes */
969 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
971 struct kmem_cache_node
*n
= get_node(s
, node
);
973 return atomic_long_read(&n
->nr_slabs
);
976 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
978 return atomic_long_read(&n
->nr_slabs
);
981 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
983 struct kmem_cache_node
*n
= get_node(s
, node
);
986 * May be called early in order to allocate a slab for the
987 * kmem_cache_node structure. Solve the chicken-egg
988 * dilemma by deferring the increment of the count during
989 * bootstrap (see early_kmem_cache_node_alloc).
992 atomic_long_inc(&n
->nr_slabs
);
993 atomic_long_add(objects
, &n
->total_objects
);
996 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
998 struct kmem_cache_node
*n
= get_node(s
, node
);
1000 atomic_long_dec(&n
->nr_slabs
);
1001 atomic_long_sub(objects
, &n
->total_objects
);
1004 /* Object debug checks for alloc/free paths */
1005 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
1008 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
1011 init_object(s
, object
, SLUB_RED_INACTIVE
);
1012 init_tracking(s
, object
);
1015 static noinline
int alloc_debug_processing(struct kmem_cache
*s
,
1017 void *object
, unsigned long addr
)
1019 if (!check_slab(s
, page
))
1022 if (!check_valid_pointer(s
, page
, object
)) {
1023 object_err(s
, page
, object
, "Freelist Pointer check fails");
1027 if (!check_object(s
, page
, object
, SLUB_RED_INACTIVE
))
1030 /* Success perform special debug activities for allocs */
1031 if (s
->flags
& SLAB_STORE_USER
)
1032 set_track(s
, object
, TRACK_ALLOC
, addr
);
1033 trace(s
, page
, object
, 1);
1034 init_object(s
, object
, SLUB_RED_ACTIVE
);
1038 if (PageSlab(page
)) {
1040 * If this is a slab page then lets do the best we can
1041 * to avoid issues in the future. Marking all objects
1042 * as used avoids touching the remaining objects.
1044 slab_fix(s
, "Marking all objects used");
1045 page
->inuse
= page
->objects
;
1046 page
->freelist
= NULL
;
1051 static noinline
struct kmem_cache_node
*free_debug_processing(
1052 struct kmem_cache
*s
, struct page
*page
, void *object
,
1053 unsigned long addr
, unsigned long *flags
)
1055 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1057 spin_lock_irqsave(&n
->list_lock
, *flags
);
1060 if (!check_slab(s
, page
))
1063 if (!check_valid_pointer(s
, page
, object
)) {
1064 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
1068 if (on_freelist(s
, page
, object
)) {
1069 object_err(s
, page
, object
, "Object already free");
1073 if (!check_object(s
, page
, object
, SLUB_RED_ACTIVE
))
1076 if (unlikely(s
!= page
->slab_cache
)) {
1077 if (!PageSlab(page
)) {
1078 slab_err(s
, page
, "Attempt to free object(0x%p) "
1079 "outside of slab", object
);
1080 } else if (!page
->slab_cache
) {
1081 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1085 object_err(s
, page
, object
,
1086 "page slab pointer corrupt.");
1090 if (s
->flags
& SLAB_STORE_USER
)
1091 set_track(s
, object
, TRACK_FREE
, addr
);
1092 trace(s
, page
, object
, 0);
1093 init_object(s
, object
, SLUB_RED_INACTIVE
);
1097 * Keep node_lock to preserve integrity
1098 * until the object is actually freed
1104 spin_unlock_irqrestore(&n
->list_lock
, *flags
);
1105 slab_fix(s
, "Object at 0x%p not freed", object
);
1109 static int __init
setup_slub_debug(char *str
)
1111 slub_debug
= DEBUG_DEFAULT_FLAGS
;
1112 if (*str
++ != '=' || !*str
)
1114 * No options specified. Switch on full debugging.
1120 * No options but restriction on slabs. This means full
1121 * debugging for slabs matching a pattern.
1125 if (tolower(*str
) == 'o') {
1127 * Avoid enabling debugging on caches if its minimum order
1128 * would increase as a result.
1130 disable_higher_order_debug
= 1;
1137 * Switch off all debugging measures.
1142 * Determine which debug features should be switched on
1144 for (; *str
&& *str
!= ','; str
++) {
1145 switch (tolower(*str
)) {
1147 slub_debug
|= SLAB_DEBUG_FREE
;
1150 slub_debug
|= SLAB_RED_ZONE
;
1153 slub_debug
|= SLAB_POISON
;
1156 slub_debug
|= SLAB_STORE_USER
;
1159 slub_debug
|= SLAB_TRACE
;
1162 slub_debug
|= SLAB_FAILSLAB
;
1165 pr_err("slub_debug option '%c' unknown. skipped\n",
1172 slub_debug_slabs
= str
+ 1;
1177 __setup("slub_debug", setup_slub_debug
);
1179 static unsigned long kmem_cache_flags(unsigned long object_size
,
1180 unsigned long flags
, const char *name
,
1181 void (*ctor
)(void *))
1184 * Enable debugging if selected on the kernel commandline.
1186 if (slub_debug
&& (!slub_debug_slabs
|| (name
&&
1187 !strncmp(slub_debug_slabs
, name
, strlen(slub_debug_slabs
)))))
1188 flags
|= slub_debug
;
1193 static inline void setup_object_debug(struct kmem_cache
*s
,
1194 struct page
*page
, void *object
) {}
1196 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1197 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1199 static inline struct kmem_cache_node
*free_debug_processing(
1200 struct kmem_cache
*s
, struct page
*page
, void *object
,
1201 unsigned long addr
, unsigned long *flags
) { return NULL
; }
1203 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1205 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1206 void *object
, u8 val
) { return 1; }
1207 static inline void add_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1208 struct page
*page
) {}
1209 static inline void remove_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1210 struct page
*page
) {}
1211 static inline unsigned long kmem_cache_flags(unsigned long object_size
,
1212 unsigned long flags
, const char *name
,
1213 void (*ctor
)(void *))
1217 #define slub_debug 0
1219 #define disable_higher_order_debug 0
1221 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1223 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1225 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
,
1227 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
,
1230 #endif /* CONFIG_SLUB_DEBUG */
1233 * Hooks for other subsystems that check memory allocations. In a typical
1234 * production configuration these hooks all should produce no code at all.
1236 static inline void kmalloc_large_node_hook(void *ptr
, size_t size
, gfp_t flags
)
1238 kmemleak_alloc(ptr
, size
, 1, flags
);
1241 static inline void kfree_hook(const void *x
)
1246 static inline int slab_pre_alloc_hook(struct kmem_cache
*s
, gfp_t flags
)
1248 flags
&= gfp_allowed_mask
;
1249 lockdep_trace_alloc(flags
);
1250 might_sleep_if(flags
& __GFP_WAIT
);
1252 return should_failslab(s
->object_size
, flags
, s
->flags
);
1255 static inline void slab_post_alloc_hook(struct kmem_cache
*s
,
1256 gfp_t flags
, void *object
)
1258 flags
&= gfp_allowed_mask
;
1259 kmemcheck_slab_alloc(s
, flags
, object
, slab_ksize(s
));
1260 kmemleak_alloc_recursive(object
, s
->object_size
, 1, s
->flags
, flags
);
1263 static inline void slab_free_hook(struct kmem_cache
*s
, void *x
)
1265 kmemleak_free_recursive(x
, s
->flags
);
1268 * Trouble is that we may no longer disable interrupts in the fast path
1269 * So in order to make the debug calls that expect irqs to be
1270 * disabled we need to disable interrupts temporarily.
1272 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1274 unsigned long flags
;
1276 local_irq_save(flags
);
1277 kmemcheck_slab_free(s
, x
, s
->object_size
);
1278 debug_check_no_locks_freed(x
, s
->object_size
);
1279 local_irq_restore(flags
);
1282 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
1283 debug_check_no_obj_freed(x
, s
->object_size
);
1287 * Slab allocation and freeing
1289 static inline struct page
*alloc_slab_page(struct kmem_cache
*s
,
1290 gfp_t flags
, int node
, struct kmem_cache_order_objects oo
)
1293 int order
= oo_order(oo
);
1295 flags
|= __GFP_NOTRACK
;
1297 if (memcg_charge_slab(s
, flags
, order
))
1300 if (node
== NUMA_NO_NODE
)
1301 page
= alloc_pages(flags
, order
);
1303 page
= alloc_pages_exact_node(node
, flags
, order
);
1306 memcg_uncharge_slab(s
, order
);
1311 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1314 struct kmem_cache_order_objects oo
= s
->oo
;
1317 flags
&= gfp_allowed_mask
;
1319 if (flags
& __GFP_WAIT
)
1322 flags
|= s
->allocflags
;
1325 * Let the initial higher-order allocation fail under memory pressure
1326 * so we fall-back to the minimum order allocation.
1328 alloc_gfp
= (flags
| __GFP_NOWARN
| __GFP_NORETRY
) & ~__GFP_NOFAIL
;
1330 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1331 if (unlikely(!page
)) {
1335 * Allocation may have failed due to fragmentation.
1336 * Try a lower order alloc if possible
1338 page
= alloc_slab_page(s
, alloc_gfp
, node
, oo
);
1341 stat(s
, ORDER_FALLBACK
);
1344 if (kmemcheck_enabled
&& page
1345 && !(s
->flags
& (SLAB_NOTRACK
| DEBUG_DEFAULT_FLAGS
))) {
1346 int pages
= 1 << oo_order(oo
);
1348 kmemcheck_alloc_shadow(page
, oo_order(oo
), alloc_gfp
, node
);
1351 * Objects from caches that have a constructor don't get
1352 * cleared when they're allocated, so we need to do it here.
1355 kmemcheck_mark_uninitialized_pages(page
, pages
);
1357 kmemcheck_mark_unallocated_pages(page
, pages
);
1360 if (flags
& __GFP_WAIT
)
1361 local_irq_disable();
1365 page
->objects
= oo_objects(oo
);
1366 mod_zone_page_state(page_zone(page
),
1367 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1368 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1374 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1377 setup_object_debug(s
, page
, object
);
1378 if (unlikely(s
->ctor
))
1382 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1390 BUG_ON(flags
& GFP_SLAB_BUG_MASK
);
1392 page
= allocate_slab(s
,
1393 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1397 order
= compound_order(page
);
1398 inc_slabs_node(s
, page_to_nid(page
), page
->objects
);
1399 page
->slab_cache
= s
;
1400 __SetPageSlab(page
);
1401 if (page
->pfmemalloc
)
1402 SetPageSlabPfmemalloc(page
);
1404 start
= page_address(page
);
1406 if (unlikely(s
->flags
& SLAB_POISON
))
1407 memset(start
, POISON_INUSE
, PAGE_SIZE
<< order
);
1409 for_each_object_idx(p
, idx
, s
, start
, page
->objects
) {
1410 setup_object(s
, page
, p
);
1411 if (likely(idx
< page
->objects
))
1412 set_freepointer(s
, p
, p
+ s
->size
);
1414 set_freepointer(s
, p
, NULL
);
1417 page
->freelist
= start
;
1418 page
->inuse
= page
->objects
;
1424 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1426 int order
= compound_order(page
);
1427 int pages
= 1 << order
;
1429 if (kmem_cache_debug(s
)) {
1432 slab_pad_check(s
, page
);
1433 for_each_object(p
, s
, page_address(page
),
1435 check_object(s
, page
, p
, SLUB_RED_INACTIVE
);
1438 kmemcheck_free_shadow(page
, compound_order(page
));
1440 mod_zone_page_state(page_zone(page
),
1441 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1442 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1445 __ClearPageSlabPfmemalloc(page
);
1446 __ClearPageSlab(page
);
1448 page_mapcount_reset(page
);
1449 if (current
->reclaim_state
)
1450 current
->reclaim_state
->reclaimed_slab
+= pages
;
1451 __free_pages(page
, order
);
1452 memcg_uncharge_slab(s
, order
);
1455 #define need_reserve_slab_rcu \
1456 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1458 static void rcu_free_slab(struct rcu_head
*h
)
1462 if (need_reserve_slab_rcu
)
1463 page
= virt_to_head_page(h
);
1465 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1467 __free_slab(page
->slab_cache
, page
);
1470 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1472 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1473 struct rcu_head
*head
;
1475 if (need_reserve_slab_rcu
) {
1476 int order
= compound_order(page
);
1477 int offset
= (PAGE_SIZE
<< order
) - s
->reserved
;
1479 VM_BUG_ON(s
->reserved
!= sizeof(*head
));
1480 head
= page_address(page
) + offset
;
1483 * RCU free overloads the RCU head over the LRU
1485 head
= (void *)&page
->lru
;
1488 call_rcu(head
, rcu_free_slab
);
1490 __free_slab(s
, page
);
1493 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1495 dec_slabs_node(s
, page_to_nid(page
), page
->objects
);
1500 * Management of partially allocated slabs.
1503 __add_partial(struct kmem_cache_node
*n
, struct page
*page
, int tail
)
1506 if (tail
== DEACTIVATE_TO_TAIL
)
1507 list_add_tail(&page
->lru
, &n
->partial
);
1509 list_add(&page
->lru
, &n
->partial
);
1512 static inline void add_partial(struct kmem_cache_node
*n
,
1513 struct page
*page
, int tail
)
1515 lockdep_assert_held(&n
->list_lock
);
1516 __add_partial(n
, page
, tail
);
1520 __remove_partial(struct kmem_cache_node
*n
, struct page
*page
)
1522 list_del(&page
->lru
);
1526 static inline void remove_partial(struct kmem_cache_node
*n
,
1529 lockdep_assert_held(&n
->list_lock
);
1530 __remove_partial(n
, page
);
1534 * Remove slab from the partial list, freeze it and
1535 * return the pointer to the freelist.
1537 * Returns a list of objects or NULL if it fails.
1539 static inline void *acquire_slab(struct kmem_cache
*s
,
1540 struct kmem_cache_node
*n
, struct page
*page
,
1541 int mode
, int *objects
)
1544 unsigned long counters
;
1547 lockdep_assert_held(&n
->list_lock
);
1550 * Zap the freelist and set the frozen bit.
1551 * The old freelist is the list of objects for the
1552 * per cpu allocation list.
1554 freelist
= page
->freelist
;
1555 counters
= page
->counters
;
1556 new.counters
= counters
;
1557 *objects
= new.objects
- new.inuse
;
1559 new.inuse
= page
->objects
;
1560 new.freelist
= NULL
;
1562 new.freelist
= freelist
;
1565 VM_BUG_ON(new.frozen
);
1568 if (!__cmpxchg_double_slab(s
, page
,
1570 new.freelist
, new.counters
,
1574 remove_partial(n
, page
);
1579 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
);
1580 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
);
1583 * Try to allocate a partial slab from a specific node.
1585 static void *get_partial_node(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1586 struct kmem_cache_cpu
*c
, gfp_t flags
)
1588 struct page
*page
, *page2
;
1589 void *object
= NULL
;
1594 * Racy check. If we mistakenly see no partial slabs then we
1595 * just allocate an empty slab. If we mistakenly try to get a
1596 * partial slab and there is none available then get_partials()
1599 if (!n
|| !n
->nr_partial
)
1602 spin_lock(&n
->list_lock
);
1603 list_for_each_entry_safe(page
, page2
, &n
->partial
, lru
) {
1606 if (!pfmemalloc_match(page
, flags
))
1609 t
= acquire_slab(s
, n
, page
, object
== NULL
, &objects
);
1613 available
+= objects
;
1616 stat(s
, ALLOC_FROM_PARTIAL
);
1619 put_cpu_partial(s
, page
, 0);
1620 stat(s
, CPU_PARTIAL_NODE
);
1622 if (!kmem_cache_has_cpu_partial(s
)
1623 || available
> s
->cpu_partial
/ 2)
1627 spin_unlock(&n
->list_lock
);
1632 * Get a page from somewhere. Search in increasing NUMA distances.
1634 static void *get_any_partial(struct kmem_cache
*s
, gfp_t flags
,
1635 struct kmem_cache_cpu
*c
)
1638 struct zonelist
*zonelist
;
1641 enum zone_type high_zoneidx
= gfp_zone(flags
);
1643 unsigned int cpuset_mems_cookie
;
1646 * The defrag ratio allows a configuration of the tradeoffs between
1647 * inter node defragmentation and node local allocations. A lower
1648 * defrag_ratio increases the tendency to do local allocations
1649 * instead of attempting to obtain partial slabs from other nodes.
1651 * If the defrag_ratio is set to 0 then kmalloc() always
1652 * returns node local objects. If the ratio is higher then kmalloc()
1653 * may return off node objects because partial slabs are obtained
1654 * from other nodes and filled up.
1656 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1657 * defrag_ratio = 1000) then every (well almost) allocation will
1658 * first attempt to defrag slab caches on other nodes. This means
1659 * scanning over all nodes to look for partial slabs which may be
1660 * expensive if we do it every time we are trying to find a slab
1661 * with available objects.
1663 if (!s
->remote_node_defrag_ratio
||
1664 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1668 cpuset_mems_cookie
= read_mems_allowed_begin();
1669 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
1670 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
1671 struct kmem_cache_node
*n
;
1673 n
= get_node(s
, zone_to_nid(zone
));
1675 if (n
&& cpuset_zone_allowed_hardwall(zone
, flags
) &&
1676 n
->nr_partial
> s
->min_partial
) {
1677 object
= get_partial_node(s
, n
, c
, flags
);
1680 * Don't check read_mems_allowed_retry()
1681 * here - if mems_allowed was updated in
1682 * parallel, that was a harmless race
1683 * between allocation and the cpuset
1690 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1696 * Get a partial page, lock it and return it.
1698 static void *get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
,
1699 struct kmem_cache_cpu
*c
)
1702 int searchnode
= (node
== NUMA_NO_NODE
) ? numa_mem_id() : node
;
1704 object
= get_partial_node(s
, get_node(s
, searchnode
), c
, flags
);
1705 if (object
|| node
!= NUMA_NO_NODE
)
1708 return get_any_partial(s
, flags
, c
);
1711 #ifdef CONFIG_PREEMPT
1713 * Calculate the next globally unique transaction for disambiguiation
1714 * during cmpxchg. The transactions start with the cpu number and are then
1715 * incremented by CONFIG_NR_CPUS.
1717 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1720 * No preemption supported therefore also no need to check for
1726 static inline unsigned long next_tid(unsigned long tid
)
1728 return tid
+ TID_STEP
;
1731 static inline unsigned int tid_to_cpu(unsigned long tid
)
1733 return tid
% TID_STEP
;
1736 static inline unsigned long tid_to_event(unsigned long tid
)
1738 return tid
/ TID_STEP
;
1741 static inline unsigned int init_tid(int cpu
)
1746 static inline void note_cmpxchg_failure(const char *n
,
1747 const struct kmem_cache
*s
, unsigned long tid
)
1749 #ifdef SLUB_DEBUG_CMPXCHG
1750 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
1752 pr_info("%s %s: cmpxchg redo ", n
, s
->name
);
1754 #ifdef CONFIG_PREEMPT
1755 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
1756 pr_warn("due to cpu change %d -> %d\n",
1757 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
1760 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
1761 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1762 tid_to_event(tid
), tid_to_event(actual_tid
));
1764 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1765 actual_tid
, tid
, next_tid(tid
));
1767 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
1770 static void init_kmem_cache_cpus(struct kmem_cache
*s
)
1774 for_each_possible_cpu(cpu
)
1775 per_cpu_ptr(s
->cpu_slab
, cpu
)->tid
= init_tid(cpu
);
1779 * Remove the cpu slab
1781 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
,
1784 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
1785 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1787 enum slab_modes l
= M_NONE
, m
= M_NONE
;
1789 int tail
= DEACTIVATE_TO_HEAD
;
1793 if (page
->freelist
) {
1794 stat(s
, DEACTIVATE_REMOTE_FREES
);
1795 tail
= DEACTIVATE_TO_TAIL
;
1799 * Stage one: Free all available per cpu objects back
1800 * to the page freelist while it is still frozen. Leave the
1803 * There is no need to take the list->lock because the page
1806 while (freelist
&& (nextfree
= get_freepointer(s
, freelist
))) {
1808 unsigned long counters
;
1811 prior
= page
->freelist
;
1812 counters
= page
->counters
;
1813 set_freepointer(s
, freelist
, prior
);
1814 new.counters
= counters
;
1816 VM_BUG_ON(!new.frozen
);
1818 } while (!__cmpxchg_double_slab(s
, page
,
1820 freelist
, new.counters
,
1821 "drain percpu freelist"));
1823 freelist
= nextfree
;
1827 * Stage two: Ensure that the page is unfrozen while the
1828 * list presence reflects the actual number of objects
1831 * We setup the list membership and then perform a cmpxchg
1832 * with the count. If there is a mismatch then the page
1833 * is not unfrozen but the page is on the wrong list.
1835 * Then we restart the process which may have to remove
1836 * the page from the list that we just put it on again
1837 * because the number of objects in the slab may have
1842 old
.freelist
= page
->freelist
;
1843 old
.counters
= page
->counters
;
1844 VM_BUG_ON(!old
.frozen
);
1846 /* Determine target state of the slab */
1847 new.counters
= old
.counters
;
1850 set_freepointer(s
, freelist
, old
.freelist
);
1851 new.freelist
= freelist
;
1853 new.freelist
= old
.freelist
;
1857 if (!new.inuse
&& n
->nr_partial
>= s
->min_partial
)
1859 else if (new.freelist
) {
1864 * Taking the spinlock removes the possiblity
1865 * that acquire_slab() will see a slab page that
1868 spin_lock(&n
->list_lock
);
1872 if (kmem_cache_debug(s
) && !lock
) {
1875 * This also ensures that the scanning of full
1876 * slabs from diagnostic functions will not see
1879 spin_lock(&n
->list_lock
);
1887 remove_partial(n
, page
);
1889 else if (l
== M_FULL
)
1891 remove_full(s
, n
, page
);
1893 if (m
== M_PARTIAL
) {
1895 add_partial(n
, page
, tail
);
1898 } else if (m
== M_FULL
) {
1900 stat(s
, DEACTIVATE_FULL
);
1901 add_full(s
, n
, page
);
1907 if (!__cmpxchg_double_slab(s
, page
,
1908 old
.freelist
, old
.counters
,
1909 new.freelist
, new.counters
,
1914 spin_unlock(&n
->list_lock
);
1917 stat(s
, DEACTIVATE_EMPTY
);
1918 discard_slab(s
, page
);
1924 * Unfreeze all the cpu partial slabs.
1926 * This function must be called with interrupts disabled
1927 * for the cpu using c (or some other guarantee must be there
1928 * to guarantee no concurrent accesses).
1930 static void unfreeze_partials(struct kmem_cache
*s
,
1931 struct kmem_cache_cpu
*c
)
1933 #ifdef CONFIG_SLUB_CPU_PARTIAL
1934 struct kmem_cache_node
*n
= NULL
, *n2
= NULL
;
1935 struct page
*page
, *discard_page
= NULL
;
1937 while ((page
= c
->partial
)) {
1941 c
->partial
= page
->next
;
1943 n2
= get_node(s
, page_to_nid(page
));
1946 spin_unlock(&n
->list_lock
);
1949 spin_lock(&n
->list_lock
);
1954 old
.freelist
= page
->freelist
;
1955 old
.counters
= page
->counters
;
1956 VM_BUG_ON(!old
.frozen
);
1958 new.counters
= old
.counters
;
1959 new.freelist
= old
.freelist
;
1963 } while (!__cmpxchg_double_slab(s
, page
,
1964 old
.freelist
, old
.counters
,
1965 new.freelist
, new.counters
,
1966 "unfreezing slab"));
1968 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
)) {
1969 page
->next
= discard_page
;
1970 discard_page
= page
;
1972 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
1973 stat(s
, FREE_ADD_PARTIAL
);
1978 spin_unlock(&n
->list_lock
);
1980 while (discard_page
) {
1981 page
= discard_page
;
1982 discard_page
= discard_page
->next
;
1984 stat(s
, DEACTIVATE_EMPTY
);
1985 discard_slab(s
, page
);
1992 * Put a page that was just frozen (in __slab_free) into a partial page
1993 * slot if available. This is done without interrupts disabled and without
1994 * preemption disabled. The cmpxchg is racy and may put the partial page
1995 * onto a random cpus partial slot.
1997 * If we did not find a slot then simply move all the partials to the
1998 * per node partial list.
2000 static void put_cpu_partial(struct kmem_cache
*s
, struct page
*page
, int drain
)
2002 #ifdef CONFIG_SLUB_CPU_PARTIAL
2003 struct page
*oldpage
;
2010 oldpage
= this_cpu_read(s
->cpu_slab
->partial
);
2013 pobjects
= oldpage
->pobjects
;
2014 pages
= oldpage
->pages
;
2015 if (drain
&& pobjects
> s
->cpu_partial
) {
2016 unsigned long flags
;
2018 * partial array is full. Move the existing
2019 * set to the per node partial list.
2021 local_irq_save(flags
);
2022 unfreeze_partials(s
, this_cpu_ptr(s
->cpu_slab
));
2023 local_irq_restore(flags
);
2027 stat(s
, CPU_PARTIAL_DRAIN
);
2032 pobjects
+= page
->objects
- page
->inuse
;
2034 page
->pages
= pages
;
2035 page
->pobjects
= pobjects
;
2036 page
->next
= oldpage
;
2038 } while (this_cpu_cmpxchg(s
->cpu_slab
->partial
, oldpage
, page
)
2043 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
2045 stat(s
, CPUSLAB_FLUSH
);
2046 deactivate_slab(s
, c
->page
, c
->freelist
);
2048 c
->tid
= next_tid(c
->tid
);
2056 * Called from IPI handler with interrupts disabled.
2058 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
2060 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2066 unfreeze_partials(s
, c
);
2070 static void flush_cpu_slab(void *d
)
2072 struct kmem_cache
*s
= d
;
2074 __flush_cpu_slab(s
, smp_processor_id());
2077 static bool has_cpu_slab(int cpu
, void *info
)
2079 struct kmem_cache
*s
= info
;
2080 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
2082 return c
->page
|| c
->partial
;
2085 static void flush_all(struct kmem_cache
*s
)
2087 on_each_cpu_cond(has_cpu_slab
, flush_cpu_slab
, s
, 1, GFP_ATOMIC
);
2091 * Check if the objects in a per cpu structure fit numa
2092 * locality expectations.
2094 static inline int node_match(struct page
*page
, int node
)
2097 if (!page
|| (node
!= NUMA_NO_NODE
&& page_to_nid(page
) != node
))
2103 #ifdef CONFIG_SLUB_DEBUG
2104 static int count_free(struct page
*page
)
2106 return page
->objects
- page
->inuse
;
2109 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
2111 return atomic_long_read(&n
->total_objects
);
2113 #endif /* CONFIG_SLUB_DEBUG */
2115 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2116 static unsigned long count_partial(struct kmem_cache_node
*n
,
2117 int (*get_count
)(struct page
*))
2119 unsigned long flags
;
2120 unsigned long x
= 0;
2123 spin_lock_irqsave(&n
->list_lock
, flags
);
2124 list_for_each_entry(page
, &n
->partial
, lru
)
2125 x
+= get_count(page
);
2126 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2129 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2131 static noinline
void
2132 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
2134 #ifdef CONFIG_SLUB_DEBUG
2135 static DEFINE_RATELIMIT_STATE(slub_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2136 DEFAULT_RATELIMIT_BURST
);
2138 struct kmem_cache_node
*n
;
2140 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slub_oom_rs
))
2143 pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2145 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2146 s
->name
, s
->object_size
, s
->size
, oo_order(s
->oo
),
2149 if (oo_order(s
->min
) > get_order(s
->object_size
))
2150 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2153 for_each_kmem_cache_node(s
, node
, n
) {
2154 unsigned long nr_slabs
;
2155 unsigned long nr_objs
;
2156 unsigned long nr_free
;
2158 nr_free
= count_partial(n
, count_free
);
2159 nr_slabs
= node_nr_slabs(n
);
2160 nr_objs
= node_nr_objs(n
);
2162 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2163 node
, nr_slabs
, nr_objs
, nr_free
);
2168 static inline void *new_slab_objects(struct kmem_cache
*s
, gfp_t flags
,
2169 int node
, struct kmem_cache_cpu
**pc
)
2172 struct kmem_cache_cpu
*c
= *pc
;
2175 freelist
= get_partial(s
, flags
, node
, c
);
2180 page
= new_slab(s
, flags
, node
);
2182 c
= raw_cpu_ptr(s
->cpu_slab
);
2187 * No other reference to the page yet so we can
2188 * muck around with it freely without cmpxchg
2190 freelist
= page
->freelist
;
2191 page
->freelist
= NULL
;
2193 stat(s
, ALLOC_SLAB
);
2202 static inline bool pfmemalloc_match(struct page
*page
, gfp_t gfpflags
)
2204 if (unlikely(PageSlabPfmemalloc(page
)))
2205 return gfp_pfmemalloc_allowed(gfpflags
);
2211 * Check the page->freelist of a page and either transfer the freelist to the
2212 * per cpu freelist or deactivate the page.
2214 * The page is still frozen if the return value is not NULL.
2216 * If this function returns NULL then the page has been unfrozen.
2218 * This function must be called with interrupt disabled.
2220 static inline void *get_freelist(struct kmem_cache
*s
, struct page
*page
)
2223 unsigned long counters
;
2227 freelist
= page
->freelist
;
2228 counters
= page
->counters
;
2230 new.counters
= counters
;
2231 VM_BUG_ON(!new.frozen
);
2233 new.inuse
= page
->objects
;
2234 new.frozen
= freelist
!= NULL
;
2236 } while (!__cmpxchg_double_slab(s
, page
,
2245 * Slow path. The lockless freelist is empty or we need to perform
2248 * Processing is still very fast if new objects have been freed to the
2249 * regular freelist. In that case we simply take over the regular freelist
2250 * as the lockless freelist and zap the regular freelist.
2252 * If that is not working then we fall back to the partial lists. We take the
2253 * first element of the freelist as the object to allocate now and move the
2254 * rest of the freelist to the lockless freelist.
2256 * And if we were unable to get a new slab from the partial slab lists then
2257 * we need to allocate a new slab. This is the slowest path since it involves
2258 * a call to the page allocator and the setup of a new slab.
2260 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
2261 unsigned long addr
, struct kmem_cache_cpu
*c
)
2265 unsigned long flags
;
2267 local_irq_save(flags
);
2268 #ifdef CONFIG_PREEMPT
2270 * We may have been preempted and rescheduled on a different
2271 * cpu before disabling interrupts. Need to reload cpu area
2274 c
= this_cpu_ptr(s
->cpu_slab
);
2282 if (unlikely(!node_match(page
, node
))) {
2283 stat(s
, ALLOC_NODE_MISMATCH
);
2284 deactivate_slab(s
, page
, c
->freelist
);
2291 * By rights, we should be searching for a slab page that was
2292 * PFMEMALLOC but right now, we are losing the pfmemalloc
2293 * information when the page leaves the per-cpu allocator
2295 if (unlikely(!pfmemalloc_match(page
, gfpflags
))) {
2296 deactivate_slab(s
, page
, c
->freelist
);
2302 /* must check again c->freelist in case of cpu migration or IRQ */
2303 freelist
= c
->freelist
;
2307 freelist
= get_freelist(s
, page
);
2311 stat(s
, DEACTIVATE_BYPASS
);
2315 stat(s
, ALLOC_REFILL
);
2319 * freelist is pointing to the list of objects to be used.
2320 * page is pointing to the page from which the objects are obtained.
2321 * That page must be frozen for per cpu allocations to work.
2323 VM_BUG_ON(!c
->page
->frozen
);
2324 c
->freelist
= get_freepointer(s
, freelist
);
2325 c
->tid
= next_tid(c
->tid
);
2326 local_irq_restore(flags
);
2332 page
= c
->page
= c
->partial
;
2333 c
->partial
= page
->next
;
2334 stat(s
, CPU_PARTIAL_ALLOC
);
2339 freelist
= new_slab_objects(s
, gfpflags
, node
, &c
);
2341 if (unlikely(!freelist
)) {
2342 slab_out_of_memory(s
, gfpflags
, node
);
2343 local_irq_restore(flags
);
2348 if (likely(!kmem_cache_debug(s
) && pfmemalloc_match(page
, gfpflags
)))
2351 /* Only entered in the debug case */
2352 if (kmem_cache_debug(s
) &&
2353 !alloc_debug_processing(s
, page
, freelist
, addr
))
2354 goto new_slab
; /* Slab failed checks. Next slab needed */
2356 deactivate_slab(s
, page
, get_freepointer(s
, freelist
));
2359 local_irq_restore(flags
);
2364 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2365 * have the fastpath folded into their functions. So no function call
2366 * overhead for requests that can be satisfied on the fastpath.
2368 * The fastpath works by first checking if the lockless freelist can be used.
2369 * If not then __slab_alloc is called for slow processing.
2371 * Otherwise we can simply pick the next object from the lockless free list.
2373 static __always_inline
void *slab_alloc_node(struct kmem_cache
*s
,
2374 gfp_t gfpflags
, int node
, unsigned long addr
)
2377 struct kmem_cache_cpu
*c
;
2381 if (slab_pre_alloc_hook(s
, gfpflags
))
2384 s
= memcg_kmem_get_cache(s
, gfpflags
);
2387 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2388 * enabled. We may switch back and forth between cpus while
2389 * reading from one cpu area. That does not matter as long
2390 * as we end up on the original cpu again when doing the cmpxchg.
2392 * Preemption is disabled for the retrieval of the tid because that
2393 * must occur from the current processor. We cannot allow rescheduling
2394 * on a different processor between the determination of the pointer
2395 * and the retrieval of the tid.
2398 c
= this_cpu_ptr(s
->cpu_slab
);
2401 * The transaction ids are globally unique per cpu and per operation on
2402 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2403 * occurs on the right processor and that there was no operation on the
2404 * linked list in between.
2409 object
= c
->freelist
;
2411 if (unlikely(!object
|| !node_match(page
, node
))) {
2412 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
2413 stat(s
, ALLOC_SLOWPATH
);
2415 void *next_object
= get_freepointer_safe(s
, object
);
2418 * The cmpxchg will only match if there was no additional
2419 * operation and if we are on the right processor.
2421 * The cmpxchg does the following atomically (without lock
2423 * 1. Relocate first pointer to the current per cpu area.
2424 * 2. Verify that tid and freelist have not been changed
2425 * 3. If they were not changed replace tid and freelist
2427 * Since this is without lock semantics the protection is only
2428 * against code executing on this cpu *not* from access by
2431 if (unlikely(!this_cpu_cmpxchg_double(
2432 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2434 next_object
, next_tid(tid
)))) {
2436 note_cmpxchg_failure("slab_alloc", s
, tid
);
2439 prefetch_freepointer(s
, next_object
);
2440 stat(s
, ALLOC_FASTPATH
);
2443 if (unlikely(gfpflags
& __GFP_ZERO
) && object
)
2444 memset(object
, 0, s
->object_size
);
2446 slab_post_alloc_hook(s
, gfpflags
, object
);
2451 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
2452 gfp_t gfpflags
, unsigned long addr
)
2454 return slab_alloc_node(s
, gfpflags
, NUMA_NO_NODE
, addr
);
2457 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
2459 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2461 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->object_size
,
2466 EXPORT_SYMBOL(kmem_cache_alloc
);
2468 #ifdef CONFIG_TRACING
2469 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
2471 void *ret
= slab_alloc(s
, gfpflags
, _RET_IP_
);
2472 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
2475 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
2479 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
2481 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2483 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
2484 s
->object_size
, s
->size
, gfpflags
, node
);
2488 EXPORT_SYMBOL(kmem_cache_alloc_node
);
2490 #ifdef CONFIG_TRACING
2491 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
2493 int node
, size_t size
)
2495 void *ret
= slab_alloc_node(s
, gfpflags
, node
, _RET_IP_
);
2497 trace_kmalloc_node(_RET_IP_
, ret
,
2498 size
, s
->size
, gfpflags
, node
);
2501 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
2506 * Slow patch handling. This may still be called frequently since objects
2507 * have a longer lifetime than the cpu slabs in most processing loads.
2509 * So we still attempt to reduce cache line usage. Just take the slab
2510 * lock and free the item. If there is no additional partial page
2511 * handling required then we can return immediately.
2513 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
2514 void *x
, unsigned long addr
)
2517 void **object
= (void *)x
;
2520 unsigned long counters
;
2521 struct kmem_cache_node
*n
= NULL
;
2522 unsigned long uninitialized_var(flags
);
2524 stat(s
, FREE_SLOWPATH
);
2526 if (kmem_cache_debug(s
) &&
2527 !(n
= free_debug_processing(s
, page
, x
, addr
, &flags
)))
2532 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2535 prior
= page
->freelist
;
2536 counters
= page
->counters
;
2537 set_freepointer(s
, object
, prior
);
2538 new.counters
= counters
;
2539 was_frozen
= new.frozen
;
2541 if ((!new.inuse
|| !prior
) && !was_frozen
) {
2543 if (kmem_cache_has_cpu_partial(s
) && !prior
) {
2546 * Slab was on no list before and will be
2548 * We can defer the list move and instead
2553 } else { /* Needs to be taken off a list */
2555 n
= get_node(s
, page_to_nid(page
));
2557 * Speculatively acquire the list_lock.
2558 * If the cmpxchg does not succeed then we may
2559 * drop the list_lock without any processing.
2561 * Otherwise the list_lock will synchronize with
2562 * other processors updating the list of slabs.
2564 spin_lock_irqsave(&n
->list_lock
, flags
);
2569 } while (!cmpxchg_double_slab(s
, page
,
2571 object
, new.counters
,
2577 * If we just froze the page then put it onto the
2578 * per cpu partial list.
2580 if (new.frozen
&& !was_frozen
) {
2581 put_cpu_partial(s
, page
, 1);
2582 stat(s
, CPU_PARTIAL_FREE
);
2585 * The list lock was not taken therefore no list
2586 * activity can be necessary.
2589 stat(s
, FREE_FROZEN
);
2593 if (unlikely(!new.inuse
&& n
->nr_partial
>= s
->min_partial
))
2597 * Objects left in the slab. If it was not on the partial list before
2600 if (!kmem_cache_has_cpu_partial(s
) && unlikely(!prior
)) {
2601 if (kmem_cache_debug(s
))
2602 remove_full(s
, n
, page
);
2603 add_partial(n
, page
, DEACTIVATE_TO_TAIL
);
2604 stat(s
, FREE_ADD_PARTIAL
);
2606 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2612 * Slab on the partial list.
2614 remove_partial(n
, page
);
2615 stat(s
, FREE_REMOVE_PARTIAL
);
2617 /* Slab must be on the full list */
2618 remove_full(s
, n
, page
);
2621 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2623 discard_slab(s
, page
);
2627 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2628 * can perform fastpath freeing without additional function calls.
2630 * The fastpath is only possible if we are freeing to the current cpu slab
2631 * of this processor. This typically the case if we have just allocated
2634 * If fastpath is not possible then fall back to __slab_free where we deal
2635 * with all sorts of special processing.
2637 static __always_inline
void slab_free(struct kmem_cache
*s
,
2638 struct page
*page
, void *x
, unsigned long addr
)
2640 void **object
= (void *)x
;
2641 struct kmem_cache_cpu
*c
;
2644 slab_free_hook(s
, x
);
2648 * Determine the currently cpus per cpu slab.
2649 * The cpu may change afterward. However that does not matter since
2650 * data is retrieved via this pointer. If we are on the same cpu
2651 * during the cmpxchg then the free will succedd.
2654 c
= this_cpu_ptr(s
->cpu_slab
);
2659 if (likely(page
== c
->page
)) {
2660 set_freepointer(s
, object
, c
->freelist
);
2662 if (unlikely(!this_cpu_cmpxchg_double(
2663 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2665 object
, next_tid(tid
)))) {
2667 note_cmpxchg_failure("slab_free", s
, tid
);
2670 stat(s
, FREE_FASTPATH
);
2672 __slab_free(s
, page
, x
, addr
);
2676 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
2678 s
= cache_from_obj(s
, x
);
2681 slab_free(s
, virt_to_head_page(x
), x
, _RET_IP_
);
2682 trace_kmem_cache_free(_RET_IP_
, x
);
2684 EXPORT_SYMBOL(kmem_cache_free
);
2687 * Object placement in a slab is made very easy because we always start at
2688 * offset 0. If we tune the size of the object to the alignment then we can
2689 * get the required alignment by putting one properly sized object after
2692 * Notice that the allocation order determines the sizes of the per cpu
2693 * caches. Each processor has always one slab available for allocations.
2694 * Increasing the allocation order reduces the number of times that slabs
2695 * must be moved on and off the partial lists and is therefore a factor in
2700 * Mininum / Maximum order of slab pages. This influences locking overhead
2701 * and slab fragmentation. A higher order reduces the number of partial slabs
2702 * and increases the number of allocations possible without having to
2703 * take the list_lock.
2705 static int slub_min_order
;
2706 static int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
2707 static int slub_min_objects
;
2710 * Merge control. If this is set then no merging of slab caches will occur.
2711 * (Could be removed. This was introduced to pacify the merge skeptics.)
2713 static int slub_nomerge
;
2716 * Calculate the order of allocation given an slab object size.
2718 * The order of allocation has significant impact on performance and other
2719 * system components. Generally order 0 allocations should be preferred since
2720 * order 0 does not cause fragmentation in the page allocator. Larger objects
2721 * be problematic to put into order 0 slabs because there may be too much
2722 * unused space left. We go to a higher order if more than 1/16th of the slab
2725 * In order to reach satisfactory performance we must ensure that a minimum
2726 * number of objects is in one slab. Otherwise we may generate too much
2727 * activity on the partial lists which requires taking the list_lock. This is
2728 * less a concern for large slabs though which are rarely used.
2730 * slub_max_order specifies the order where we begin to stop considering the
2731 * number of objects in a slab as critical. If we reach slub_max_order then
2732 * we try to keep the page order as low as possible. So we accept more waste
2733 * of space in favor of a small page order.
2735 * Higher order allocations also allow the placement of more objects in a
2736 * slab and thereby reduce object handling overhead. If the user has
2737 * requested a higher mininum order then we start with that one instead of
2738 * the smallest order which will fit the object.
2740 static inline int slab_order(int size
, int min_objects
,
2741 int max_order
, int fract_leftover
, int reserved
)
2745 int min_order
= slub_min_order
;
2747 if (order_objects(min_order
, size
, reserved
) > MAX_OBJS_PER_PAGE
)
2748 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
2750 for (order
= max(min_order
,
2751 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
2752 order
<= max_order
; order
++) {
2754 unsigned long slab_size
= PAGE_SIZE
<< order
;
2756 if (slab_size
< min_objects
* size
+ reserved
)
2759 rem
= (slab_size
- reserved
) % size
;
2761 if (rem
<= slab_size
/ fract_leftover
)
2769 static inline int calculate_order(int size
, int reserved
)
2777 * Attempt to find best configuration for a slab. This
2778 * works by first attempting to generate a layout with
2779 * the best configuration and backing off gradually.
2781 * First we reduce the acceptable waste in a slab. Then
2782 * we reduce the minimum objects required in a slab.
2784 min_objects
= slub_min_objects
;
2786 min_objects
= 4 * (fls(nr_cpu_ids
) + 1);
2787 max_objects
= order_objects(slub_max_order
, size
, reserved
);
2788 min_objects
= min(min_objects
, max_objects
);
2790 while (min_objects
> 1) {
2792 while (fraction
>= 4) {
2793 order
= slab_order(size
, min_objects
,
2794 slub_max_order
, fraction
, reserved
);
2795 if (order
<= slub_max_order
)
2803 * We were unable to place multiple objects in a slab. Now
2804 * lets see if we can place a single object there.
2806 order
= slab_order(size
, 1, slub_max_order
, 1, reserved
);
2807 if (order
<= slub_max_order
)
2811 * Doh this slab cannot be placed using slub_max_order.
2813 order
= slab_order(size
, 1, MAX_ORDER
, 1, reserved
);
2814 if (order
< MAX_ORDER
)
2820 init_kmem_cache_node(struct kmem_cache_node
*n
)
2823 spin_lock_init(&n
->list_lock
);
2824 INIT_LIST_HEAD(&n
->partial
);
2825 #ifdef CONFIG_SLUB_DEBUG
2826 atomic_long_set(&n
->nr_slabs
, 0);
2827 atomic_long_set(&n
->total_objects
, 0);
2828 INIT_LIST_HEAD(&n
->full
);
2832 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
2834 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
2835 KMALLOC_SHIFT_HIGH
* sizeof(struct kmem_cache_cpu
));
2838 * Must align to double word boundary for the double cmpxchg
2839 * instructions to work; see __pcpu_double_call_return_bool().
2841 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
2842 2 * sizeof(void *));
2847 init_kmem_cache_cpus(s
);
2852 static struct kmem_cache
*kmem_cache_node
;
2855 * No kmalloc_node yet so do it by hand. We know that this is the first
2856 * slab on the node for this slabcache. There are no concurrent accesses
2859 * Note that this function only works on the kmem_cache_node
2860 * when allocating for the kmem_cache_node. This is used for bootstrapping
2861 * memory on a fresh node that has no slab structures yet.
2863 static void early_kmem_cache_node_alloc(int node
)
2866 struct kmem_cache_node
*n
;
2868 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
2870 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
2873 if (page_to_nid(page
) != node
) {
2874 pr_err("SLUB: Unable to allocate memory from node %d\n", node
);
2875 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
2880 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
2883 kmem_cache_node
->node
[node
] = n
;
2884 #ifdef CONFIG_SLUB_DEBUG
2885 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
2886 init_tracking(kmem_cache_node
, n
);
2888 init_kmem_cache_node(n
);
2889 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
2892 * No locks need to be taken here as it has just been
2893 * initialized and there is no concurrent access.
2895 __add_partial(n
, page
, DEACTIVATE_TO_HEAD
);
2898 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2901 struct kmem_cache_node
*n
;
2903 for_each_kmem_cache_node(s
, node
, n
) {
2904 kmem_cache_free(kmem_cache_node
, n
);
2905 s
->node
[node
] = NULL
;
2909 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
2913 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2914 struct kmem_cache_node
*n
;
2916 if (slab_state
== DOWN
) {
2917 early_kmem_cache_node_alloc(node
);
2920 n
= kmem_cache_alloc_node(kmem_cache_node
,
2924 free_kmem_cache_nodes(s
);
2929 init_kmem_cache_node(n
);
2934 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
2936 if (min
< MIN_PARTIAL
)
2938 else if (min
> MAX_PARTIAL
)
2940 s
->min_partial
= min
;
2944 * calculate_sizes() determines the order and the distribution of data within
2947 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
2949 unsigned long flags
= s
->flags
;
2950 unsigned long size
= s
->object_size
;
2954 * Round up object size to the next word boundary. We can only
2955 * place the free pointer at word boundaries and this determines
2956 * the possible location of the free pointer.
2958 size
= ALIGN(size
, sizeof(void *));
2960 #ifdef CONFIG_SLUB_DEBUG
2962 * Determine if we can poison the object itself. If the user of
2963 * the slab may touch the object after free or before allocation
2964 * then we should never poison the object itself.
2966 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
2968 s
->flags
|= __OBJECT_POISON
;
2970 s
->flags
&= ~__OBJECT_POISON
;
2974 * If we are Redzoning then check if there is some space between the
2975 * end of the object and the free pointer. If not then add an
2976 * additional word to have some bytes to store Redzone information.
2978 if ((flags
& SLAB_RED_ZONE
) && size
== s
->object_size
)
2979 size
+= sizeof(void *);
2983 * With that we have determined the number of bytes in actual use
2984 * by the object. This is the potential offset to the free pointer.
2988 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
2991 * Relocate free pointer after the object if it is not
2992 * permitted to overwrite the first word of the object on
2995 * This is the case if we do RCU, have a constructor or
2996 * destructor or are poisoning the objects.
2999 size
+= sizeof(void *);
3002 #ifdef CONFIG_SLUB_DEBUG
3003 if (flags
& SLAB_STORE_USER
)
3005 * Need to store information about allocs and frees after
3008 size
+= 2 * sizeof(struct track
);
3010 if (flags
& SLAB_RED_ZONE
)
3012 * Add some empty padding so that we can catch
3013 * overwrites from earlier objects rather than let
3014 * tracking information or the free pointer be
3015 * corrupted if a user writes before the start
3018 size
+= sizeof(void *);
3022 * SLUB stores one object immediately after another beginning from
3023 * offset 0. In order to align the objects we have to simply size
3024 * each object to conform to the alignment.
3026 size
= ALIGN(size
, s
->align
);
3028 if (forced_order
>= 0)
3029 order
= forced_order
;
3031 order
= calculate_order(size
, s
->reserved
);
3038 s
->allocflags
|= __GFP_COMP
;
3040 if (s
->flags
& SLAB_CACHE_DMA
)
3041 s
->allocflags
|= GFP_DMA
;
3043 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3044 s
->allocflags
|= __GFP_RECLAIMABLE
;
3047 * Determine the number of objects per slab
3049 s
->oo
= oo_make(order
, size
, s
->reserved
);
3050 s
->min
= oo_make(get_order(size
), size
, s
->reserved
);
3051 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
3054 return !!oo_objects(s
->oo
);
3057 static int kmem_cache_open(struct kmem_cache
*s
, unsigned long flags
)
3059 s
->flags
= kmem_cache_flags(s
->size
, flags
, s
->name
, s
->ctor
);
3062 if (need_reserve_slab_rcu
&& (s
->flags
& SLAB_DESTROY_BY_RCU
))
3063 s
->reserved
= sizeof(struct rcu_head
);
3065 if (!calculate_sizes(s
, -1))
3067 if (disable_higher_order_debug
) {
3069 * Disable debugging flags that store metadata if the min slab
3072 if (get_order(s
->size
) > get_order(s
->object_size
)) {
3073 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
3075 if (!calculate_sizes(s
, -1))
3080 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3081 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3082 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_DEBUG_FLAGS
) == 0)
3083 /* Enable fast mode */
3084 s
->flags
|= __CMPXCHG_DOUBLE
;
3088 * The larger the object size is, the more pages we want on the partial
3089 * list to avoid pounding the page allocator excessively.
3091 set_min_partial(s
, ilog2(s
->size
) / 2);
3094 * cpu_partial determined the maximum number of objects kept in the
3095 * per cpu partial lists of a processor.
3097 * Per cpu partial lists mainly contain slabs that just have one
3098 * object freed. If they are used for allocation then they can be
3099 * filled up again with minimal effort. The slab will never hit the
3100 * per node partial lists and therefore no locking will be required.
3102 * This setting also determines
3104 * A) The number of objects from per cpu partial slabs dumped to the
3105 * per node list when we reach the limit.
3106 * B) The number of objects in cpu partial slabs to extract from the
3107 * per node list when we run out of per cpu objects. We only fetch
3108 * 50% to keep some capacity around for frees.
3110 if (!kmem_cache_has_cpu_partial(s
))
3112 else if (s
->size
>= PAGE_SIZE
)
3114 else if (s
->size
>= 1024)
3116 else if (s
->size
>= 256)
3117 s
->cpu_partial
= 13;
3119 s
->cpu_partial
= 30;
3122 s
->remote_node_defrag_ratio
= 1000;
3124 if (!init_kmem_cache_nodes(s
))
3127 if (alloc_kmem_cache_cpus(s
))
3130 free_kmem_cache_nodes(s
);
3132 if (flags
& SLAB_PANIC
)
3133 panic("Cannot create slab %s size=%lu realsize=%u "
3134 "order=%u offset=%u flags=%lx\n",
3135 s
->name
, (unsigned long)s
->size
, s
->size
,
3136 oo_order(s
->oo
), s
->offset
, flags
);
3140 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
3143 #ifdef CONFIG_SLUB_DEBUG
3144 void *addr
= page_address(page
);
3146 unsigned long *map
= kzalloc(BITS_TO_LONGS(page
->objects
) *
3147 sizeof(long), GFP_ATOMIC
);
3150 slab_err(s
, page
, text
, s
->name
);
3153 get_map(s
, page
, map
);
3154 for_each_object(p
, s
, addr
, page
->objects
) {
3156 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
3157 pr_err("INFO: Object 0x%p @offset=%tu\n", p
, p
- addr
);
3158 print_tracking(s
, p
);
3167 * Attempt to free all partial slabs on a node.
3168 * This is called from kmem_cache_close(). We must be the last thread
3169 * using the cache and therefore we do not need to lock anymore.
3171 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
3173 struct page
*page
, *h
;
3175 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
3177 __remove_partial(n
, page
);
3178 discard_slab(s
, page
);
3180 list_slab_objects(s
, page
,
3181 "Objects remaining in %s on kmem_cache_close()");
3187 * Release all resources used by a slab cache.
3189 static inline int kmem_cache_close(struct kmem_cache
*s
)
3192 struct kmem_cache_node
*n
;
3195 /* Attempt to free all objects */
3196 for_each_kmem_cache_node(s
, node
, n
) {
3198 if (n
->nr_partial
|| slabs_node(s
, node
))
3201 free_percpu(s
->cpu_slab
);
3202 free_kmem_cache_nodes(s
);
3206 int __kmem_cache_shutdown(struct kmem_cache
*s
)
3208 return kmem_cache_close(s
);
3211 /********************************************************************
3213 *******************************************************************/
3215 static int __init
setup_slub_min_order(char *str
)
3217 get_option(&str
, &slub_min_order
);
3222 __setup("slub_min_order=", setup_slub_min_order
);
3224 static int __init
setup_slub_max_order(char *str
)
3226 get_option(&str
, &slub_max_order
);
3227 slub_max_order
= min(slub_max_order
, MAX_ORDER
- 1);
3232 __setup("slub_max_order=", setup_slub_max_order
);
3234 static int __init
setup_slub_min_objects(char *str
)
3236 get_option(&str
, &slub_min_objects
);
3241 __setup("slub_min_objects=", setup_slub_min_objects
);
3243 static int __init
setup_slub_nomerge(char *str
)
3249 __setup("slub_nomerge", setup_slub_nomerge
);
3251 void *__kmalloc(size_t size
, gfp_t flags
)
3253 struct kmem_cache
*s
;
3256 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3257 return kmalloc_large(size
, flags
);
3259 s
= kmalloc_slab(size
, flags
);
3261 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3264 ret
= slab_alloc(s
, flags
, _RET_IP_
);
3266 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
3270 EXPORT_SYMBOL(__kmalloc
);
3273 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
3278 flags
|= __GFP_COMP
| __GFP_NOTRACK
;
3279 page
= alloc_kmem_pages_node(node
, flags
, get_order(size
));
3281 ptr
= page_address(page
);
3283 kmalloc_large_node_hook(ptr
, size
, flags
);
3287 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3289 struct kmem_cache
*s
;
3292 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3293 ret
= kmalloc_large_node(size
, flags
, node
);
3295 trace_kmalloc_node(_RET_IP_
, ret
,
3296 size
, PAGE_SIZE
<< get_order(size
),
3302 s
= kmalloc_slab(size
, flags
);
3304 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3307 ret
= slab_alloc_node(s
, flags
, node
, _RET_IP_
);
3309 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
3313 EXPORT_SYMBOL(__kmalloc_node
);
3316 size_t ksize(const void *object
)
3320 if (unlikely(object
== ZERO_SIZE_PTR
))
3323 page
= virt_to_head_page(object
);
3325 if (unlikely(!PageSlab(page
))) {
3326 WARN_ON(!PageCompound(page
));
3327 return PAGE_SIZE
<< compound_order(page
);
3330 return slab_ksize(page
->slab_cache
);
3332 EXPORT_SYMBOL(ksize
);
3334 void kfree(const void *x
)
3337 void *object
= (void *)x
;
3339 trace_kfree(_RET_IP_
, x
);
3341 if (unlikely(ZERO_OR_NULL_PTR(x
)))
3344 page
= virt_to_head_page(x
);
3345 if (unlikely(!PageSlab(page
))) {
3346 BUG_ON(!PageCompound(page
));
3348 __free_kmem_pages(page
, compound_order(page
));
3351 slab_free(page
->slab_cache
, page
, object
, _RET_IP_
);
3353 EXPORT_SYMBOL(kfree
);
3356 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3357 * the remaining slabs by the number of items in use. The slabs with the
3358 * most items in use come first. New allocations will then fill those up
3359 * and thus they can be removed from the partial lists.
3361 * The slabs with the least items are placed last. This results in them
3362 * being allocated from last increasing the chance that the last objects
3363 * are freed in them.
3365 int __kmem_cache_shrink(struct kmem_cache
*s
)
3369 struct kmem_cache_node
*n
;
3372 int objects
= oo_objects(s
->max
);
3373 struct list_head
*slabs_by_inuse
=
3374 kmalloc(sizeof(struct list_head
) * objects
, GFP_KERNEL
);
3375 unsigned long flags
;
3377 if (!slabs_by_inuse
)
3381 for_each_kmem_cache_node(s
, node
, n
) {
3385 for (i
= 0; i
< objects
; i
++)
3386 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
3388 spin_lock_irqsave(&n
->list_lock
, flags
);
3391 * Build lists indexed by the items in use in each slab.
3393 * Note that concurrent frees may occur while we hold the
3394 * list_lock. page->inuse here is the upper limit.
3396 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
3397 list_move(&page
->lru
, slabs_by_inuse
+ page
->inuse
);
3403 * Rebuild the partial list with the slabs filled up most
3404 * first and the least used slabs at the end.
3406 for (i
= objects
- 1; i
> 0; i
--)
3407 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
3409 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3411 /* Release empty slabs */
3412 list_for_each_entry_safe(page
, t
, slabs_by_inuse
, lru
)
3413 discard_slab(s
, page
);
3416 kfree(slabs_by_inuse
);
3420 static int slab_mem_going_offline_callback(void *arg
)
3422 struct kmem_cache
*s
;
3424 mutex_lock(&slab_mutex
);
3425 list_for_each_entry(s
, &slab_caches
, list
)
3426 __kmem_cache_shrink(s
);
3427 mutex_unlock(&slab_mutex
);
3432 static void slab_mem_offline_callback(void *arg
)
3434 struct kmem_cache_node
*n
;
3435 struct kmem_cache
*s
;
3436 struct memory_notify
*marg
= arg
;
3439 offline_node
= marg
->status_change_nid_normal
;
3442 * If the node still has available memory. we need kmem_cache_node
3445 if (offline_node
< 0)
3448 mutex_lock(&slab_mutex
);
3449 list_for_each_entry(s
, &slab_caches
, list
) {
3450 n
= get_node(s
, offline_node
);
3453 * if n->nr_slabs > 0, slabs still exist on the node
3454 * that is going down. We were unable to free them,
3455 * and offline_pages() function shouldn't call this
3456 * callback. So, we must fail.
3458 BUG_ON(slabs_node(s
, offline_node
));
3460 s
->node
[offline_node
] = NULL
;
3461 kmem_cache_free(kmem_cache_node
, n
);
3464 mutex_unlock(&slab_mutex
);
3467 static int slab_mem_going_online_callback(void *arg
)
3469 struct kmem_cache_node
*n
;
3470 struct kmem_cache
*s
;
3471 struct memory_notify
*marg
= arg
;
3472 int nid
= marg
->status_change_nid_normal
;
3476 * If the node's memory is already available, then kmem_cache_node is
3477 * already created. Nothing to do.
3483 * We are bringing a node online. No memory is available yet. We must
3484 * allocate a kmem_cache_node structure in order to bring the node
3487 mutex_lock(&slab_mutex
);
3488 list_for_each_entry(s
, &slab_caches
, list
) {
3490 * XXX: kmem_cache_alloc_node will fallback to other nodes
3491 * since memory is not yet available from the node that
3494 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
3499 init_kmem_cache_node(n
);
3503 mutex_unlock(&slab_mutex
);
3507 static int slab_memory_callback(struct notifier_block
*self
,
3508 unsigned long action
, void *arg
)
3513 case MEM_GOING_ONLINE
:
3514 ret
= slab_mem_going_online_callback(arg
);
3516 case MEM_GOING_OFFLINE
:
3517 ret
= slab_mem_going_offline_callback(arg
);
3520 case MEM_CANCEL_ONLINE
:
3521 slab_mem_offline_callback(arg
);
3524 case MEM_CANCEL_OFFLINE
:
3528 ret
= notifier_from_errno(ret
);
3534 static struct notifier_block slab_memory_callback_nb
= {
3535 .notifier_call
= slab_memory_callback
,
3536 .priority
= SLAB_CALLBACK_PRI
,
3539 /********************************************************************
3540 * Basic setup of slabs
3541 *******************************************************************/
3544 * Used for early kmem_cache structures that were allocated using
3545 * the page allocator. Allocate them properly then fix up the pointers
3546 * that may be pointing to the wrong kmem_cache structure.
3549 static struct kmem_cache
* __init
bootstrap(struct kmem_cache
*static_cache
)
3552 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
3553 struct kmem_cache_node
*n
;
3555 memcpy(s
, static_cache
, kmem_cache
->object_size
);
3558 * This runs very early, and only the boot processor is supposed to be
3559 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3562 __flush_cpu_slab(s
, smp_processor_id());
3563 for_each_kmem_cache_node(s
, node
, n
) {
3566 list_for_each_entry(p
, &n
->partial
, lru
)
3569 #ifdef CONFIG_SLUB_DEBUG
3570 list_for_each_entry(p
, &n
->full
, lru
)
3574 list_add(&s
->list
, &slab_caches
);
3578 void __init
kmem_cache_init(void)
3580 static __initdata
struct kmem_cache boot_kmem_cache
,
3581 boot_kmem_cache_node
;
3583 if (debug_guardpage_minorder())
3586 kmem_cache_node
= &boot_kmem_cache_node
;
3587 kmem_cache
= &boot_kmem_cache
;
3589 create_boot_cache(kmem_cache_node
, "kmem_cache_node",
3590 sizeof(struct kmem_cache_node
), SLAB_HWCACHE_ALIGN
);
3592 register_hotmemory_notifier(&slab_memory_callback_nb
);
3594 /* Able to allocate the per node structures */
3595 slab_state
= PARTIAL
;
3597 create_boot_cache(kmem_cache
, "kmem_cache",
3598 offsetof(struct kmem_cache
, node
) +
3599 nr_node_ids
* sizeof(struct kmem_cache_node
*),
3600 SLAB_HWCACHE_ALIGN
);
3602 kmem_cache
= bootstrap(&boot_kmem_cache
);
3605 * Allocate kmem_cache_node properly from the kmem_cache slab.
3606 * kmem_cache_node is separately allocated so no need to
3607 * update any list pointers.
3609 kmem_cache_node
= bootstrap(&boot_kmem_cache_node
);
3611 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3612 create_kmalloc_caches(0);
3615 register_cpu_notifier(&slab_notifier
);
3618 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
3620 slub_min_order
, slub_max_order
, slub_min_objects
,
3621 nr_cpu_ids
, nr_node_ids
);
3624 void __init
kmem_cache_init_late(void)
3629 * Find a mergeable slab cache
3631 static int slab_unmergeable(struct kmem_cache
*s
)
3633 if (slub_nomerge
|| (s
->flags
& SLUB_NEVER_MERGE
))
3636 if (!is_root_cache(s
))
3643 * We may have set a slab to be unmergeable during bootstrap.
3645 if (s
->refcount
< 0)
3651 static struct kmem_cache
*find_mergeable(size_t size
, size_t align
,
3652 unsigned long flags
, const char *name
, void (*ctor
)(void *))
3654 struct kmem_cache
*s
;
3656 if (slub_nomerge
|| (flags
& SLUB_NEVER_MERGE
))
3662 size
= ALIGN(size
, sizeof(void *));
3663 align
= calculate_alignment(flags
, align
, size
);
3664 size
= ALIGN(size
, align
);
3665 flags
= kmem_cache_flags(size
, flags
, name
, NULL
);
3667 list_for_each_entry(s
, &slab_caches
, list
) {
3668 if (slab_unmergeable(s
))
3674 if ((flags
& SLUB_MERGE_SAME
) != (s
->flags
& SLUB_MERGE_SAME
))
3677 * Check if alignment is compatible.
3678 * Courtesy of Adrian Drzewiecki
3680 if ((s
->size
& ~(align
- 1)) != s
->size
)
3683 if (s
->size
- size
>= sizeof(void *))
3692 __kmem_cache_alias(const char *name
, size_t size
, size_t align
,
3693 unsigned long flags
, void (*ctor
)(void *))
3695 struct kmem_cache
*s
;
3697 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3700 struct kmem_cache
*c
;
3705 * Adjust the object sizes so that we clear
3706 * the complete object on kzalloc.
3708 s
->object_size
= max(s
->object_size
, (int)size
);
3709 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3711 for_each_memcg_cache_index(i
) {
3712 c
= cache_from_memcg_idx(s
, i
);
3715 c
->object_size
= s
->object_size
;
3716 c
->inuse
= max_t(int, c
->inuse
,
3717 ALIGN(size
, sizeof(void *)));
3720 if (sysfs_slab_alias(s
, name
)) {
3729 int __kmem_cache_create(struct kmem_cache
*s
, unsigned long flags
)
3733 err
= kmem_cache_open(s
, flags
);
3737 /* Mutex is not taken during early boot */
3738 if (slab_state
<= UP
)
3741 memcg_propagate_slab_attrs(s
);
3742 err
= sysfs_slab_add(s
);
3744 kmem_cache_close(s
);
3751 * Use the cpu notifier to insure that the cpu slabs are flushed when
3754 static int slab_cpuup_callback(struct notifier_block
*nfb
,
3755 unsigned long action
, void *hcpu
)
3757 long cpu
= (long)hcpu
;
3758 struct kmem_cache
*s
;
3759 unsigned long flags
;
3762 case CPU_UP_CANCELED
:
3763 case CPU_UP_CANCELED_FROZEN
:
3765 case CPU_DEAD_FROZEN
:
3766 mutex_lock(&slab_mutex
);
3767 list_for_each_entry(s
, &slab_caches
, list
) {
3768 local_irq_save(flags
);
3769 __flush_cpu_slab(s
, cpu
);
3770 local_irq_restore(flags
);
3772 mutex_unlock(&slab_mutex
);
3780 static struct notifier_block slab_notifier
= {
3781 .notifier_call
= slab_cpuup_callback
3786 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
3788 struct kmem_cache
*s
;
3791 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3792 return kmalloc_large(size
, gfpflags
);
3794 s
= kmalloc_slab(size
, gfpflags
);
3796 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3799 ret
= slab_alloc(s
, gfpflags
, caller
);
3801 /* Honor the call site pointer we received. */
3802 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
3808 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3809 int node
, unsigned long caller
)
3811 struct kmem_cache
*s
;
3814 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
)) {
3815 ret
= kmalloc_large_node(size
, gfpflags
, node
);
3817 trace_kmalloc_node(caller
, ret
,
3818 size
, PAGE_SIZE
<< get_order(size
),
3824 s
= kmalloc_slab(size
, gfpflags
);
3826 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3829 ret
= slab_alloc_node(s
, gfpflags
, node
, caller
);
3831 /* Honor the call site pointer we received. */
3832 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
3839 static int count_inuse(struct page
*page
)
3844 static int count_total(struct page
*page
)
3846 return page
->objects
;
3850 #ifdef CONFIG_SLUB_DEBUG
3851 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3855 void *addr
= page_address(page
);
3857 if (!check_slab(s
, page
) ||
3858 !on_freelist(s
, page
, NULL
))
3861 /* Now we know that a valid freelist exists */
3862 bitmap_zero(map
, page
->objects
);
3864 get_map(s
, page
, map
);
3865 for_each_object(p
, s
, addr
, page
->objects
) {
3866 if (test_bit(slab_index(p
, s
, addr
), map
))
3867 if (!check_object(s
, page
, p
, SLUB_RED_INACTIVE
))
3871 for_each_object(p
, s
, addr
, page
->objects
)
3872 if (!test_bit(slab_index(p
, s
, addr
), map
))
3873 if (!check_object(s
, page
, p
, SLUB_RED_ACTIVE
))
3878 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
3882 validate_slab(s
, page
, map
);
3886 static int validate_slab_node(struct kmem_cache
*s
,
3887 struct kmem_cache_node
*n
, unsigned long *map
)
3889 unsigned long count
= 0;
3891 unsigned long flags
;
3893 spin_lock_irqsave(&n
->list_lock
, flags
);
3895 list_for_each_entry(page
, &n
->partial
, lru
) {
3896 validate_slab_slab(s
, page
, map
);
3899 if (count
!= n
->nr_partial
)
3900 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
3901 s
->name
, count
, n
->nr_partial
);
3903 if (!(s
->flags
& SLAB_STORE_USER
))
3906 list_for_each_entry(page
, &n
->full
, lru
) {
3907 validate_slab_slab(s
, page
, map
);
3910 if (count
!= atomic_long_read(&n
->nr_slabs
))
3911 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
3912 s
->name
, count
, atomic_long_read(&n
->nr_slabs
));
3915 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3919 static long validate_slab_cache(struct kmem_cache
*s
)
3922 unsigned long count
= 0;
3923 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
3924 sizeof(unsigned long), GFP_KERNEL
);
3925 struct kmem_cache_node
*n
;
3931 for_each_kmem_cache_node(s
, node
, n
)
3932 count
+= validate_slab_node(s
, n
, map
);
3937 * Generate lists of code addresses where slabcache objects are allocated
3942 unsigned long count
;
3949 DECLARE_BITMAP(cpus
, NR_CPUS
);
3955 unsigned long count
;
3956 struct location
*loc
;
3959 static void free_loc_track(struct loc_track
*t
)
3962 free_pages((unsigned long)t
->loc
,
3963 get_order(sizeof(struct location
) * t
->max
));
3966 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
3971 order
= get_order(sizeof(struct location
) * max
);
3973 l
= (void *)__get_free_pages(flags
, order
);
3978 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
3986 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
3987 const struct track
*track
)
3989 long start
, end
, pos
;
3991 unsigned long caddr
;
3992 unsigned long age
= jiffies
- track
->when
;
3998 pos
= start
+ (end
- start
+ 1) / 2;
4001 * There is nothing at "end". If we end up there
4002 * we need to add something to before end.
4007 caddr
= t
->loc
[pos
].addr
;
4008 if (track
->addr
== caddr
) {
4014 if (age
< l
->min_time
)
4016 if (age
> l
->max_time
)
4019 if (track
->pid
< l
->min_pid
)
4020 l
->min_pid
= track
->pid
;
4021 if (track
->pid
> l
->max_pid
)
4022 l
->max_pid
= track
->pid
;
4024 cpumask_set_cpu(track
->cpu
,
4025 to_cpumask(l
->cpus
));
4027 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4031 if (track
->addr
< caddr
)
4038 * Not found. Insert new tracking element.
4040 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
4046 (t
->count
- pos
) * sizeof(struct location
));
4049 l
->addr
= track
->addr
;
4053 l
->min_pid
= track
->pid
;
4054 l
->max_pid
= track
->pid
;
4055 cpumask_clear(to_cpumask(l
->cpus
));
4056 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
4057 nodes_clear(l
->nodes
);
4058 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4062 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
4063 struct page
*page
, enum track_item alloc
,
4066 void *addr
= page_address(page
);
4069 bitmap_zero(map
, page
->objects
);
4070 get_map(s
, page
, map
);
4072 for_each_object(p
, s
, addr
, page
->objects
)
4073 if (!test_bit(slab_index(p
, s
, addr
), map
))
4074 add_location(t
, s
, get_track(s
, p
, alloc
));
4077 static int list_locations(struct kmem_cache
*s
, char *buf
,
4078 enum track_item alloc
)
4082 struct loc_track t
= { 0, 0, NULL
};
4084 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4085 sizeof(unsigned long), GFP_KERNEL
);
4086 struct kmem_cache_node
*n
;
4088 if (!map
|| !alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
4091 return sprintf(buf
, "Out of memory\n");
4093 /* Push back cpu slabs */
4096 for_each_kmem_cache_node(s
, node
, n
) {
4097 unsigned long flags
;
4100 if (!atomic_long_read(&n
->nr_slabs
))
4103 spin_lock_irqsave(&n
->list_lock
, flags
);
4104 list_for_each_entry(page
, &n
->partial
, lru
)
4105 process_slab(&t
, s
, page
, alloc
, map
);
4106 list_for_each_entry(page
, &n
->full
, lru
)
4107 process_slab(&t
, s
, page
, alloc
, map
);
4108 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4111 for (i
= 0; i
< t
.count
; i
++) {
4112 struct location
*l
= &t
.loc
[i
];
4114 if (len
> PAGE_SIZE
- KSYM_SYMBOL_LEN
- 100)
4116 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
4119 len
+= sprintf(buf
+ len
, "%pS", (void *)l
->addr
);
4121 len
+= sprintf(buf
+ len
, "<not-available>");
4123 if (l
->sum_time
!= l
->min_time
) {
4124 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
4126 (long)div_u64(l
->sum_time
, l
->count
),
4129 len
+= sprintf(buf
+ len
, " age=%ld",
4132 if (l
->min_pid
!= l
->max_pid
)
4133 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
4134 l
->min_pid
, l
->max_pid
);
4136 len
+= sprintf(buf
+ len
, " pid=%ld",
4139 if (num_online_cpus() > 1 &&
4140 !cpumask_empty(to_cpumask(l
->cpus
)) &&
4141 len
< PAGE_SIZE
- 60) {
4142 len
+= sprintf(buf
+ len
, " cpus=");
4143 len
+= cpulist_scnprintf(buf
+ len
,
4144 PAGE_SIZE
- len
- 50,
4145 to_cpumask(l
->cpus
));
4148 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
) &&
4149 len
< PAGE_SIZE
- 60) {
4150 len
+= sprintf(buf
+ len
, " nodes=");
4151 len
+= nodelist_scnprintf(buf
+ len
,
4152 PAGE_SIZE
- len
- 50,
4156 len
+= sprintf(buf
+ len
, "\n");
4162 len
+= sprintf(buf
, "No data\n");
4167 #ifdef SLUB_RESILIENCY_TEST
4168 static void __init
resiliency_test(void)
4172 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 16 || KMALLOC_SHIFT_HIGH
< 10);
4174 pr_err("SLUB resiliency testing\n");
4175 pr_err("-----------------------\n");
4176 pr_err("A. Corruption after allocation\n");
4178 p
= kzalloc(16, GFP_KERNEL
);
4180 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4183 validate_slab_cache(kmalloc_caches
[4]);
4185 /* Hmmm... The next two are dangerous */
4186 p
= kzalloc(32, GFP_KERNEL
);
4187 p
[32 + sizeof(void *)] = 0x34;
4188 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4190 pr_err("If allocated object is overwritten then not detectable\n\n");
4192 validate_slab_cache(kmalloc_caches
[5]);
4193 p
= kzalloc(64, GFP_KERNEL
);
4194 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
4196 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4198 pr_err("If allocated object is overwritten then not detectable\n\n");
4199 validate_slab_cache(kmalloc_caches
[6]);
4201 pr_err("\nB. Corruption after free\n");
4202 p
= kzalloc(128, GFP_KERNEL
);
4205 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
4206 validate_slab_cache(kmalloc_caches
[7]);
4208 p
= kzalloc(256, GFP_KERNEL
);
4211 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
4212 validate_slab_cache(kmalloc_caches
[8]);
4214 p
= kzalloc(512, GFP_KERNEL
);
4217 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
4218 validate_slab_cache(kmalloc_caches
[9]);
4222 static void resiliency_test(void) {};
4227 enum slab_stat_type
{
4228 SL_ALL
, /* All slabs */
4229 SL_PARTIAL
, /* Only partially allocated slabs */
4230 SL_CPU
, /* Only slabs used for cpu caches */
4231 SL_OBJECTS
, /* Determine allocated objects not slabs */
4232 SL_TOTAL
/* Determine object capacity not slabs */
4235 #define SO_ALL (1 << SL_ALL)
4236 #define SO_PARTIAL (1 << SL_PARTIAL)
4237 #define SO_CPU (1 << SL_CPU)
4238 #define SO_OBJECTS (1 << SL_OBJECTS)
4239 #define SO_TOTAL (1 << SL_TOTAL)
4241 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
4242 char *buf
, unsigned long flags
)
4244 unsigned long total
= 0;
4247 unsigned long *nodes
;
4249 nodes
= kzalloc(sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
4253 if (flags
& SO_CPU
) {
4256 for_each_possible_cpu(cpu
) {
4257 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
,
4262 page
= ACCESS_ONCE(c
->page
);
4266 node
= page_to_nid(page
);
4267 if (flags
& SO_TOTAL
)
4269 else if (flags
& SO_OBJECTS
)
4277 page
= ACCESS_ONCE(c
->partial
);
4279 node
= page_to_nid(page
);
4280 if (flags
& SO_TOTAL
)
4282 else if (flags
& SO_OBJECTS
)
4293 #ifdef CONFIG_SLUB_DEBUG
4294 if (flags
& SO_ALL
) {
4295 struct kmem_cache_node
*n
;
4297 for_each_kmem_cache_node(s
, node
, n
) {
4299 if (flags
& SO_TOTAL
)
4300 x
= atomic_long_read(&n
->total_objects
);
4301 else if (flags
& SO_OBJECTS
)
4302 x
= atomic_long_read(&n
->total_objects
) -
4303 count_partial(n
, count_free
);
4305 x
= atomic_long_read(&n
->nr_slabs
);
4312 if (flags
& SO_PARTIAL
) {
4313 struct kmem_cache_node
*n
;
4315 for_each_kmem_cache_node(s
, node
, n
) {
4316 if (flags
& SO_TOTAL
)
4317 x
= count_partial(n
, count_total
);
4318 else if (flags
& SO_OBJECTS
)
4319 x
= count_partial(n
, count_inuse
);
4326 x
= sprintf(buf
, "%lu", total
);
4328 for (node
= 0; node
< nr_node_ids
; node
++)
4330 x
+= sprintf(buf
+ x
, " N%d=%lu",
4335 return x
+ sprintf(buf
+ x
, "\n");
4338 #ifdef CONFIG_SLUB_DEBUG
4339 static int any_slab_objects(struct kmem_cache
*s
)
4342 struct kmem_cache_node
*n
;
4344 for_each_kmem_cache_node(s
, node
, n
)
4345 if (atomic_long_read(&n
->total_objects
))
4352 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4353 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4355 struct slab_attribute
{
4356 struct attribute attr
;
4357 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
4358 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
4361 #define SLAB_ATTR_RO(_name) \
4362 static struct slab_attribute _name##_attr = \
4363 __ATTR(_name, 0400, _name##_show, NULL)
4365 #define SLAB_ATTR(_name) \
4366 static struct slab_attribute _name##_attr = \
4367 __ATTR(_name, 0600, _name##_show, _name##_store)
4369 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
4371 return sprintf(buf
, "%d\n", s
->size
);
4373 SLAB_ATTR_RO(slab_size
);
4375 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
4377 return sprintf(buf
, "%d\n", s
->align
);
4379 SLAB_ATTR_RO(align
);
4381 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
4383 return sprintf(buf
, "%d\n", s
->object_size
);
4385 SLAB_ATTR_RO(object_size
);
4387 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
4389 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
4391 SLAB_ATTR_RO(objs_per_slab
);
4393 static ssize_t
order_store(struct kmem_cache
*s
,
4394 const char *buf
, size_t length
)
4396 unsigned long order
;
4399 err
= kstrtoul(buf
, 10, &order
);
4403 if (order
> slub_max_order
|| order
< slub_min_order
)
4406 calculate_sizes(s
, order
);
4410 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
4412 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
4416 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
4418 return sprintf(buf
, "%lu\n", s
->min_partial
);
4421 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
4427 err
= kstrtoul(buf
, 10, &min
);
4431 set_min_partial(s
, min
);
4434 SLAB_ATTR(min_partial
);
4436 static ssize_t
cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4438 return sprintf(buf
, "%u\n", s
->cpu_partial
);
4441 static ssize_t
cpu_partial_store(struct kmem_cache
*s
, const char *buf
,
4444 unsigned long objects
;
4447 err
= kstrtoul(buf
, 10, &objects
);
4450 if (objects
&& !kmem_cache_has_cpu_partial(s
))
4453 s
->cpu_partial
= objects
;
4457 SLAB_ATTR(cpu_partial
);
4459 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
4463 return sprintf(buf
, "%pS\n", s
->ctor
);
4467 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
4469 return sprintf(buf
, "%d\n", s
->refcount
< 0 ? 0 : s
->refcount
- 1);
4471 SLAB_ATTR_RO(aliases
);
4473 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
4475 return show_slab_objects(s
, buf
, SO_PARTIAL
);
4477 SLAB_ATTR_RO(partial
);
4479 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
4481 return show_slab_objects(s
, buf
, SO_CPU
);
4483 SLAB_ATTR_RO(cpu_slabs
);
4485 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
4487 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
4489 SLAB_ATTR_RO(objects
);
4491 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
4493 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
4495 SLAB_ATTR_RO(objects_partial
);
4497 static ssize_t
slabs_cpu_partial_show(struct kmem_cache
*s
, char *buf
)
4504 for_each_online_cpu(cpu
) {
4505 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
)->partial
;
4508 pages
+= page
->pages
;
4509 objects
+= page
->pobjects
;
4513 len
= sprintf(buf
, "%d(%d)", objects
, pages
);
4516 for_each_online_cpu(cpu
) {
4517 struct page
*page
= per_cpu_ptr(s
->cpu_slab
, cpu
) ->partial
;
4519 if (page
&& len
< PAGE_SIZE
- 20)
4520 len
+= sprintf(buf
+ len
, " C%d=%d(%d)", cpu
,
4521 page
->pobjects
, page
->pages
);
4524 return len
+ sprintf(buf
+ len
, "\n");
4526 SLAB_ATTR_RO(slabs_cpu_partial
);
4528 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
4530 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
4533 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
4534 const char *buf
, size_t length
)
4536 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
4538 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
4541 SLAB_ATTR(reclaim_account
);
4543 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
4545 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
4547 SLAB_ATTR_RO(hwcache_align
);
4549 #ifdef CONFIG_ZONE_DMA
4550 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
4552 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
4554 SLAB_ATTR_RO(cache_dma
);
4557 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
4559 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
4561 SLAB_ATTR_RO(destroy_by_rcu
);
4563 static ssize_t
reserved_show(struct kmem_cache
*s
, char *buf
)
4565 return sprintf(buf
, "%d\n", s
->reserved
);
4567 SLAB_ATTR_RO(reserved
);
4569 #ifdef CONFIG_SLUB_DEBUG
4570 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
4572 return show_slab_objects(s
, buf
, SO_ALL
);
4574 SLAB_ATTR_RO(slabs
);
4576 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
4578 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
4580 SLAB_ATTR_RO(total_objects
);
4582 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
4584 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
4587 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
4588 const char *buf
, size_t length
)
4590 s
->flags
&= ~SLAB_DEBUG_FREE
;
4591 if (buf
[0] == '1') {
4592 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4593 s
->flags
|= SLAB_DEBUG_FREE
;
4597 SLAB_ATTR(sanity_checks
);
4599 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
4601 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
4604 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
4607 s
->flags
&= ~SLAB_TRACE
;
4608 if (buf
[0] == '1') {
4609 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4610 s
->flags
|= SLAB_TRACE
;
4616 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
4618 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
4621 static ssize_t
red_zone_store(struct kmem_cache
*s
,
4622 const char *buf
, size_t length
)
4624 if (any_slab_objects(s
))
4627 s
->flags
&= ~SLAB_RED_ZONE
;
4628 if (buf
[0] == '1') {
4629 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4630 s
->flags
|= SLAB_RED_ZONE
;
4632 calculate_sizes(s
, -1);
4635 SLAB_ATTR(red_zone
);
4637 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
4639 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
4642 static ssize_t
poison_store(struct kmem_cache
*s
,
4643 const char *buf
, size_t length
)
4645 if (any_slab_objects(s
))
4648 s
->flags
&= ~SLAB_POISON
;
4649 if (buf
[0] == '1') {
4650 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4651 s
->flags
|= SLAB_POISON
;
4653 calculate_sizes(s
, -1);
4658 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
4660 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
4663 static ssize_t
store_user_store(struct kmem_cache
*s
,
4664 const char *buf
, size_t length
)
4666 if (any_slab_objects(s
))
4669 s
->flags
&= ~SLAB_STORE_USER
;
4670 if (buf
[0] == '1') {
4671 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4672 s
->flags
|= SLAB_STORE_USER
;
4674 calculate_sizes(s
, -1);
4677 SLAB_ATTR(store_user
);
4679 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4684 static ssize_t
validate_store(struct kmem_cache
*s
,
4685 const char *buf
, size_t length
)
4689 if (buf
[0] == '1') {
4690 ret
= validate_slab_cache(s
);
4696 SLAB_ATTR(validate
);
4698 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4700 if (!(s
->flags
& SLAB_STORE_USER
))
4702 return list_locations(s
, buf
, TRACK_ALLOC
);
4704 SLAB_ATTR_RO(alloc_calls
);
4706 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4708 if (!(s
->flags
& SLAB_STORE_USER
))
4710 return list_locations(s
, buf
, TRACK_FREE
);
4712 SLAB_ATTR_RO(free_calls
);
4713 #endif /* CONFIG_SLUB_DEBUG */
4715 #ifdef CONFIG_FAILSLAB
4716 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
4718 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
4721 static ssize_t
failslab_store(struct kmem_cache
*s
, const char *buf
,
4724 s
->flags
&= ~SLAB_FAILSLAB
;
4726 s
->flags
|= SLAB_FAILSLAB
;
4729 SLAB_ATTR(failslab
);
4732 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4737 static ssize_t
shrink_store(struct kmem_cache
*s
,
4738 const char *buf
, size_t length
)
4740 if (buf
[0] == '1') {
4741 int rc
= kmem_cache_shrink(s
);
4752 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4754 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4757 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4758 const char *buf
, size_t length
)
4760 unsigned long ratio
;
4763 err
= kstrtoul(buf
, 10, &ratio
);
4768 s
->remote_node_defrag_ratio
= ratio
* 10;
4772 SLAB_ATTR(remote_node_defrag_ratio
);
4775 #ifdef CONFIG_SLUB_STATS
4776 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
4778 unsigned long sum
= 0;
4781 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
4786 for_each_online_cpu(cpu
) {
4787 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
4793 len
= sprintf(buf
, "%lu", sum
);
4796 for_each_online_cpu(cpu
) {
4797 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
4798 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
4802 return len
+ sprintf(buf
+ len
, "\n");
4805 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
4809 for_each_online_cpu(cpu
)
4810 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
4813 #define STAT_ATTR(si, text) \
4814 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4816 return show_stat(s, buf, si); \
4818 static ssize_t text##_store(struct kmem_cache *s, \
4819 const char *buf, size_t length) \
4821 if (buf[0] != '0') \
4823 clear_stat(s, si); \
4828 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4829 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
4830 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
4831 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
4832 STAT_ATTR(FREE_FROZEN
, free_frozen
);
4833 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
4834 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
4835 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
4836 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
4837 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
4838 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
4839 STAT_ATTR(FREE_SLAB
, free_slab
);
4840 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
4841 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
4842 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
4843 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4844 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4845 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4846 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
4847 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
4848 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
4849 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
4850 STAT_ATTR(CPU_PARTIAL_ALLOC
, cpu_partial_alloc
);
4851 STAT_ATTR(CPU_PARTIAL_FREE
, cpu_partial_free
);
4852 STAT_ATTR(CPU_PARTIAL_NODE
, cpu_partial_node
);
4853 STAT_ATTR(CPU_PARTIAL_DRAIN
, cpu_partial_drain
);
4856 static struct attribute
*slab_attrs
[] = {
4857 &slab_size_attr
.attr
,
4858 &object_size_attr
.attr
,
4859 &objs_per_slab_attr
.attr
,
4861 &min_partial_attr
.attr
,
4862 &cpu_partial_attr
.attr
,
4864 &objects_partial_attr
.attr
,
4866 &cpu_slabs_attr
.attr
,
4870 &hwcache_align_attr
.attr
,
4871 &reclaim_account_attr
.attr
,
4872 &destroy_by_rcu_attr
.attr
,
4874 &reserved_attr
.attr
,
4875 &slabs_cpu_partial_attr
.attr
,
4876 #ifdef CONFIG_SLUB_DEBUG
4877 &total_objects_attr
.attr
,
4879 &sanity_checks_attr
.attr
,
4881 &red_zone_attr
.attr
,
4883 &store_user_attr
.attr
,
4884 &validate_attr
.attr
,
4885 &alloc_calls_attr
.attr
,
4886 &free_calls_attr
.attr
,
4888 #ifdef CONFIG_ZONE_DMA
4889 &cache_dma_attr
.attr
,
4892 &remote_node_defrag_ratio_attr
.attr
,
4894 #ifdef CONFIG_SLUB_STATS
4895 &alloc_fastpath_attr
.attr
,
4896 &alloc_slowpath_attr
.attr
,
4897 &free_fastpath_attr
.attr
,
4898 &free_slowpath_attr
.attr
,
4899 &free_frozen_attr
.attr
,
4900 &free_add_partial_attr
.attr
,
4901 &free_remove_partial_attr
.attr
,
4902 &alloc_from_partial_attr
.attr
,
4903 &alloc_slab_attr
.attr
,
4904 &alloc_refill_attr
.attr
,
4905 &alloc_node_mismatch_attr
.attr
,
4906 &free_slab_attr
.attr
,
4907 &cpuslab_flush_attr
.attr
,
4908 &deactivate_full_attr
.attr
,
4909 &deactivate_empty_attr
.attr
,
4910 &deactivate_to_head_attr
.attr
,
4911 &deactivate_to_tail_attr
.attr
,
4912 &deactivate_remote_frees_attr
.attr
,
4913 &deactivate_bypass_attr
.attr
,
4914 &order_fallback_attr
.attr
,
4915 &cmpxchg_double_fail_attr
.attr
,
4916 &cmpxchg_double_cpu_fail_attr
.attr
,
4917 &cpu_partial_alloc_attr
.attr
,
4918 &cpu_partial_free_attr
.attr
,
4919 &cpu_partial_node_attr
.attr
,
4920 &cpu_partial_drain_attr
.attr
,
4922 #ifdef CONFIG_FAILSLAB
4923 &failslab_attr
.attr
,
4929 static struct attribute_group slab_attr_group
= {
4930 .attrs
= slab_attrs
,
4933 static ssize_t
slab_attr_show(struct kobject
*kobj
,
4934 struct attribute
*attr
,
4937 struct slab_attribute
*attribute
;
4938 struct kmem_cache
*s
;
4941 attribute
= to_slab_attr(attr
);
4944 if (!attribute
->show
)
4947 err
= attribute
->show(s
, buf
);
4952 static ssize_t
slab_attr_store(struct kobject
*kobj
,
4953 struct attribute
*attr
,
4954 const char *buf
, size_t len
)
4956 struct slab_attribute
*attribute
;
4957 struct kmem_cache
*s
;
4960 attribute
= to_slab_attr(attr
);
4963 if (!attribute
->store
)
4966 err
= attribute
->store(s
, buf
, len
);
4967 #ifdef CONFIG_MEMCG_KMEM
4968 if (slab_state
>= FULL
&& err
>= 0 && is_root_cache(s
)) {
4971 mutex_lock(&slab_mutex
);
4972 if (s
->max_attr_size
< len
)
4973 s
->max_attr_size
= len
;
4976 * This is a best effort propagation, so this function's return
4977 * value will be determined by the parent cache only. This is
4978 * basically because not all attributes will have a well
4979 * defined semantics for rollbacks - most of the actions will
4980 * have permanent effects.
4982 * Returning the error value of any of the children that fail
4983 * is not 100 % defined, in the sense that users seeing the
4984 * error code won't be able to know anything about the state of
4987 * Only returning the error code for the parent cache at least
4988 * has well defined semantics. The cache being written to
4989 * directly either failed or succeeded, in which case we loop
4990 * through the descendants with best-effort propagation.
4992 for_each_memcg_cache_index(i
) {
4993 struct kmem_cache
*c
= cache_from_memcg_idx(s
, i
);
4995 attribute
->store(c
, buf
, len
);
4997 mutex_unlock(&slab_mutex
);
5003 static void memcg_propagate_slab_attrs(struct kmem_cache
*s
)
5005 #ifdef CONFIG_MEMCG_KMEM
5007 char *buffer
= NULL
;
5008 struct kmem_cache
*root_cache
;
5010 if (is_root_cache(s
))
5013 root_cache
= s
->memcg_params
->root_cache
;
5016 * This mean this cache had no attribute written. Therefore, no point
5017 * in copying default values around
5019 if (!root_cache
->max_attr_size
)
5022 for (i
= 0; i
< ARRAY_SIZE(slab_attrs
); i
++) {
5025 struct slab_attribute
*attr
= to_slab_attr(slab_attrs
[i
]);
5027 if (!attr
|| !attr
->store
|| !attr
->show
)
5031 * It is really bad that we have to allocate here, so we will
5032 * do it only as a fallback. If we actually allocate, though,
5033 * we can just use the allocated buffer until the end.
5035 * Most of the slub attributes will tend to be very small in
5036 * size, but sysfs allows buffers up to a page, so they can
5037 * theoretically happen.
5041 else if (root_cache
->max_attr_size
< ARRAY_SIZE(mbuf
))
5044 buffer
= (char *) get_zeroed_page(GFP_KERNEL
);
5045 if (WARN_ON(!buffer
))
5050 attr
->show(root_cache
, buf
);
5051 attr
->store(s
, buf
, strlen(buf
));
5055 free_page((unsigned long)buffer
);
5059 static void kmem_cache_release(struct kobject
*k
)
5061 slab_kmem_cache_release(to_slab(k
));
5064 static const struct sysfs_ops slab_sysfs_ops
= {
5065 .show
= slab_attr_show
,
5066 .store
= slab_attr_store
,
5069 static struct kobj_type slab_ktype
= {
5070 .sysfs_ops
= &slab_sysfs_ops
,
5071 .release
= kmem_cache_release
,
5074 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
5076 struct kobj_type
*ktype
= get_ktype(kobj
);
5078 if (ktype
== &slab_ktype
)
5083 static const struct kset_uevent_ops slab_uevent_ops
= {
5084 .filter
= uevent_filter
,
5087 static struct kset
*slab_kset
;
5089 static inline struct kset
*cache_kset(struct kmem_cache
*s
)
5091 #ifdef CONFIG_MEMCG_KMEM
5092 if (!is_root_cache(s
))
5093 return s
->memcg_params
->root_cache
->memcg_kset
;
5098 #define ID_STR_LENGTH 64
5100 /* Create a unique string id for a slab cache:
5102 * Format :[flags-]size
5104 static char *create_unique_id(struct kmem_cache
*s
)
5106 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
5113 * First flags affecting slabcache operations. We will only
5114 * get here for aliasable slabs so we do not need to support
5115 * too many flags. The flags here must cover all flags that
5116 * are matched during merging to guarantee that the id is
5119 if (s
->flags
& SLAB_CACHE_DMA
)
5121 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
5123 if (s
->flags
& SLAB_DEBUG_FREE
)
5125 if (!(s
->flags
& SLAB_NOTRACK
))
5129 p
+= sprintf(p
, "%07d", s
->size
);
5131 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
5135 static int sysfs_slab_add(struct kmem_cache
*s
)
5139 int unmergeable
= slab_unmergeable(s
);
5143 * Slabcache can never be merged so we can use the name proper.
5144 * This is typically the case for debug situations. In that
5145 * case we can catch duplicate names easily.
5147 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
5151 * Create a unique name for the slab as a target
5154 name
= create_unique_id(s
);
5157 s
->kobj
.kset
= cache_kset(s
);
5158 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, "%s", name
);
5162 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
5166 #ifdef CONFIG_MEMCG_KMEM
5167 if (is_root_cache(s
)) {
5168 s
->memcg_kset
= kset_create_and_add("cgroup", NULL
, &s
->kobj
);
5169 if (!s
->memcg_kset
) {
5176 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
5178 /* Setup first alias */
5179 sysfs_slab_alias(s
, s
->name
);
5186 kobject_del(&s
->kobj
);
5188 kobject_put(&s
->kobj
);
5192 void sysfs_slab_remove(struct kmem_cache
*s
)
5194 if (slab_state
< FULL
)
5196 * Sysfs has not been setup yet so no need to remove the
5201 #ifdef CONFIG_MEMCG_KMEM
5202 kset_unregister(s
->memcg_kset
);
5204 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
5205 kobject_del(&s
->kobj
);
5206 kobject_put(&s
->kobj
);
5210 * Need to buffer aliases during bootup until sysfs becomes
5211 * available lest we lose that information.
5213 struct saved_alias
{
5214 struct kmem_cache
*s
;
5216 struct saved_alias
*next
;
5219 static struct saved_alias
*alias_list
;
5221 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5223 struct saved_alias
*al
;
5225 if (slab_state
== FULL
) {
5227 * If we have a leftover link then remove it.
5229 sysfs_remove_link(&slab_kset
->kobj
, name
);
5230 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5233 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5239 al
->next
= alias_list
;
5244 static int __init
slab_sysfs_init(void)
5246 struct kmem_cache
*s
;
5249 mutex_lock(&slab_mutex
);
5251 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
5253 mutex_unlock(&slab_mutex
);
5254 pr_err("Cannot register slab subsystem.\n");
5260 list_for_each_entry(s
, &slab_caches
, list
) {
5261 err
= sysfs_slab_add(s
);
5263 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5267 while (alias_list
) {
5268 struct saved_alias
*al
= alias_list
;
5270 alias_list
= alias_list
->next
;
5271 err
= sysfs_slab_alias(al
->s
, al
->name
);
5273 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5278 mutex_unlock(&slab_mutex
);
5283 __initcall(slab_sysfs_init
);
5284 #endif /* CONFIG_SYSFS */
5287 * The /proc/slabinfo ABI
5289 #ifdef CONFIG_SLABINFO
5290 void get_slabinfo(struct kmem_cache
*s
, struct slabinfo
*sinfo
)
5292 unsigned long nr_slabs
= 0;
5293 unsigned long nr_objs
= 0;
5294 unsigned long nr_free
= 0;
5296 struct kmem_cache_node
*n
;
5298 for_each_kmem_cache_node(s
, node
, n
) {
5299 nr_slabs
+= node_nr_slabs(n
);
5300 nr_objs
+= node_nr_objs(n
);
5301 nr_free
+= count_partial(n
, count_free
);
5304 sinfo
->active_objs
= nr_objs
- nr_free
;
5305 sinfo
->num_objs
= nr_objs
;
5306 sinfo
->active_slabs
= nr_slabs
;
5307 sinfo
->num_slabs
= nr_slabs
;
5308 sinfo
->objects_per_slab
= oo_objects(s
->oo
);
5309 sinfo
->cache_order
= oo_order(s
->oo
);
5312 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*s
)
5316 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
5317 size_t count
, loff_t
*ppos
)
5321 #endif /* CONFIG_SLABINFO */