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 and only
6 * uses a centralized lock to manage a pool of partial slabs.
8 * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
12 #include <linux/module.h>
13 #include <linux/bit_spinlock.h>
14 #include <linux/interrupt.h>
15 #include <linux/bitops.h>
16 #include <linux/slab.h>
17 #include <linux/seq_file.h>
18 #include <linux/cpu.h>
19 #include <linux/cpuset.h>
20 #include <linux/mempolicy.h>
21 #include <linux/ctype.h>
22 #include <linux/kallsyms.h>
29 * The slab_lock protects operations on the object of a particular
30 * slab and its metadata in the page struct. If the slab lock
31 * has been taken then no allocations nor frees can be performed
32 * on the objects in the slab nor can the slab be added or removed
33 * from the partial or full lists since this would mean modifying
34 * the page_struct of the slab.
36 * The list_lock protects the partial and full list on each node and
37 * the partial slab counter. If taken then no new slabs may be added or
38 * removed from the lists nor make the number of partial slabs be modified.
39 * (Note that the total number of slabs is an atomic value that may be
40 * modified without taking the list lock).
42 * The list_lock is a centralized lock and thus we avoid taking it as
43 * much as possible. As long as SLUB does not have to handle partial
44 * slabs, operations can continue without any centralized lock. F.e.
45 * allocating a long series of objects that fill up slabs does not require
48 * The lock order is sometimes inverted when we are trying to get a slab
49 * off a list. We take the list_lock and then look for a page on the list
50 * to use. While we do that objects in the slabs may be freed. We can
51 * only operate on the slab if we have also taken the slab_lock. So we use
52 * a slab_trylock() on the slab. If trylock was successful then no frees
53 * can occur anymore and we can use the slab for allocations etc. If the
54 * slab_trylock() does not succeed then frees are in progress in the slab and
55 * we must stay away from it for a while since we may cause a bouncing
56 * cacheline if we try to acquire the lock. So go onto the next slab.
57 * If all pages are busy then we may allocate a new slab instead of reusing
58 * a partial slab. A new slab has noone operating on it and thus there is
59 * no danger of cacheline contention.
61 * Interrupts are disabled during allocation and deallocation in order to
62 * make the slab allocator safe to use in the context of an irq. In addition
63 * interrupts are disabled to ensure that the processor does not change
64 * while handling per_cpu slabs, due to kernel preemption.
66 * SLUB assigns one slab for allocation to each processor.
67 * Allocations only occur from these slabs called cpu slabs.
69 * Slabs with free elements are kept on a partial list and during regular
70 * operations no list for full slabs is used. If an object in a full slab is
71 * freed then the slab will show up again on the partial lists.
72 * We track full slabs for debugging purposes though because otherwise we
73 * cannot scan all objects.
75 * Slabs are freed when they become empty. Teardown and setup is
76 * minimal so we rely on the page allocators per cpu caches for
77 * fast frees and allocs.
79 * Overloading of page flags that are otherwise used for LRU management.
81 * PageActive The slab is frozen and exempt from list processing.
82 * This means that the slab is dedicated to a purpose
83 * such as satisfying allocations for a specific
84 * processor. Objects may be freed in the slab while
85 * it is frozen but slab_free will then skip the usual
86 * list operations. It is up to the processor holding
87 * the slab to integrate the slab into the slab lists
88 * when the slab is no longer needed.
90 * One use of this flag is to mark slabs that are
91 * used for allocations. Then such a slab becomes a cpu
92 * slab. The cpu slab may be equipped with an additional
93 * freelist that allows lockless access to
94 * free objects in addition to the regular freelist
95 * that requires the slab lock.
97 * PageError Slab requires special handling due to debug
98 * options set. This moves slab handling out of
99 * the fast path and disables lockless freelists.
102 #define FROZEN (1 << PG_active)
104 #ifdef CONFIG_SLUB_DEBUG
105 #define SLABDEBUG (1 << PG_error)
110 static inline int SlabFrozen(struct page
*page
)
112 return page
->flags
& FROZEN
;
115 static inline void SetSlabFrozen(struct page
*page
)
117 page
->flags
|= FROZEN
;
120 static inline void ClearSlabFrozen(struct page
*page
)
122 page
->flags
&= ~FROZEN
;
125 static inline int SlabDebug(struct page
*page
)
127 return page
->flags
& SLABDEBUG
;
130 static inline void SetSlabDebug(struct page
*page
)
132 page
->flags
|= SLABDEBUG
;
135 static inline void ClearSlabDebug(struct page
*page
)
137 page
->flags
&= ~SLABDEBUG
;
141 * Issues still to be resolved:
143 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
145 * - Variable sizing of the per node arrays
148 /* Enable to test recovery from slab corruption on boot */
149 #undef SLUB_RESILIENCY_TEST
154 * Small page size. Make sure that we do not fragment memory
156 #define DEFAULT_MAX_ORDER 1
157 #define DEFAULT_MIN_OBJECTS 4
162 * Large page machines are customarily able to handle larger
165 #define DEFAULT_MAX_ORDER 2
166 #define DEFAULT_MIN_OBJECTS 8
171 * Mininum number of partial slabs. These will be left on the partial
172 * lists even if they are empty. kmem_cache_shrink may reclaim them.
174 #define MIN_PARTIAL 2
177 * Maximum number of desirable partial slabs.
178 * The existence of more partial slabs makes kmem_cache_shrink
179 * sort the partial list by the number of objects in the.
181 #define MAX_PARTIAL 10
183 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
184 SLAB_POISON | SLAB_STORE_USER)
187 * Set of flags that will prevent slab merging
189 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
190 SLAB_TRACE | SLAB_DESTROY_BY_RCU)
192 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
195 #ifndef ARCH_KMALLOC_MINALIGN
196 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
199 #ifndef ARCH_SLAB_MINALIGN
200 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
204 * The page->inuse field is 16 bit thus we have this limitation
206 #define MAX_OBJECTS_PER_SLAB 65535
208 /* Internal SLUB flags */
209 #define __OBJECT_POISON 0x80000000 /* Poison object */
210 #define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */
212 /* Not all arches define cache_line_size */
213 #ifndef cache_line_size
214 #define cache_line_size() L1_CACHE_BYTES
217 static int kmem_size
= sizeof(struct kmem_cache
);
220 static struct notifier_block slab_notifier
;
224 DOWN
, /* No slab functionality available */
225 PARTIAL
, /* kmem_cache_open() works but kmalloc does not */
226 UP
, /* Everything works but does not show up in sysfs */
230 /* A list of all slab caches on the system */
231 static DECLARE_RWSEM(slub_lock
);
232 static LIST_HEAD(slab_caches
);
235 * Tracking user of a slab.
238 void *addr
; /* Called from address */
239 int cpu
; /* Was running on cpu */
240 int pid
; /* Pid context */
241 unsigned long when
; /* When did the operation occur */
244 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
246 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
247 static int sysfs_slab_add(struct kmem_cache
*);
248 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
249 static void sysfs_slab_remove(struct kmem_cache
*);
251 static inline int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
252 static inline int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
)
254 static inline void sysfs_slab_remove(struct kmem_cache
*s
) {}
257 /********************************************************************
258 * Core slab cache functions
259 *******************************************************************/
261 int slab_is_available(void)
263 return slab_state
>= UP
;
266 static inline struct kmem_cache_node
*get_node(struct kmem_cache
*s
, int node
)
269 return s
->node
[node
];
271 return &s
->local_node
;
275 static inline struct kmem_cache_cpu
*get_cpu_slab(struct kmem_cache
*s
, int cpu
)
277 return &s
->cpu_slab
[cpu
];
280 static inline int check_valid_pointer(struct kmem_cache
*s
,
281 struct page
*page
, const void *object
)
288 base
= page_address(page
);
289 if (object
< base
|| object
>= base
+ s
->objects
* s
->size
||
290 (object
- base
) % s
->size
) {
298 * Slow version of get and set free pointer.
300 * This version requires touching the cache lines of kmem_cache which
301 * we avoid to do in the fast alloc free paths. There we obtain the offset
302 * from the page struct.
304 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
306 return *(void **)(object
+ s
->offset
);
309 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
311 *(void **)(object
+ s
->offset
) = fp
;
314 /* Loop over all objects in a slab */
315 #define for_each_object(__p, __s, __addr) \
316 for (__p = (__addr); __p < (__addr) + (__s)->objects * (__s)->size;\
320 #define for_each_free_object(__p, __s, __free) \
321 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
323 /* Determine object index from a given position */
324 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
326 return (p
- addr
) / s
->size
;
329 #ifdef CONFIG_SLUB_DEBUG
333 #ifdef CONFIG_SLUB_DEBUG_ON
334 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
336 static int slub_debug
;
339 static char *slub_debug_slabs
;
344 static void print_section(char *text
, u8
*addr
, unsigned int length
)
352 for (i
= 0; i
< length
; i
++) {
354 printk(KERN_ERR
"%8s 0x%p: ", text
, addr
+ i
);
357 printk(" %02x", addr
[i
]);
359 ascii
[offset
] = isgraph(addr
[i
]) ? addr
[i
] : '.';
361 printk(" %s\n",ascii
);
372 printk(" %s\n", ascii
);
376 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
377 enum track_item alloc
)
382 p
= object
+ s
->offset
+ sizeof(void *);
384 p
= object
+ s
->inuse
;
389 static void set_track(struct kmem_cache
*s
, void *object
,
390 enum track_item alloc
, void *addr
)
395 p
= object
+ s
->offset
+ sizeof(void *);
397 p
= object
+ s
->inuse
;
402 p
->cpu
= smp_processor_id();
403 p
->pid
= current
? current
->pid
: -1;
406 memset(p
, 0, sizeof(struct track
));
409 static void init_tracking(struct kmem_cache
*s
, void *object
)
411 if (!(s
->flags
& SLAB_STORE_USER
))
414 set_track(s
, object
, TRACK_FREE
, NULL
);
415 set_track(s
, object
, TRACK_ALLOC
, NULL
);
418 static void print_track(const char *s
, struct track
*t
)
423 printk(KERN_ERR
"INFO: %s in ", s
);
424 __print_symbol("%s", (unsigned long)t
->addr
);
425 printk(" age=%lu cpu=%u pid=%d\n", jiffies
- t
->when
, t
->cpu
, t
->pid
);
428 static void print_tracking(struct kmem_cache
*s
, void *object
)
430 if (!(s
->flags
& SLAB_STORE_USER
))
433 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
434 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
437 static void print_page_info(struct page
*page
)
439 printk(KERN_ERR
"INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n",
440 page
, page
->inuse
, page
->freelist
, page
->flags
);
444 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
450 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
452 printk(KERN_ERR
"========================================"
453 "=====================================\n");
454 printk(KERN_ERR
"BUG %s: %s\n", s
->name
, buf
);
455 printk(KERN_ERR
"----------------------------------------"
456 "-------------------------------------\n\n");
459 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
465 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
467 printk(KERN_ERR
"FIX %s: %s\n", s
->name
, buf
);
470 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
472 unsigned int off
; /* Offset of last byte */
473 u8
*addr
= page_address(page
);
475 print_tracking(s
, p
);
477 print_page_info(page
);
479 printk(KERN_ERR
"INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
480 p
, p
- addr
, get_freepointer(s
, p
));
483 print_section("Bytes b4", p
- 16, 16);
485 print_section("Object", p
, min(s
->objsize
, 128));
487 if (s
->flags
& SLAB_RED_ZONE
)
488 print_section("Redzone", p
+ s
->objsize
,
489 s
->inuse
- s
->objsize
);
492 off
= s
->offset
+ sizeof(void *);
496 if (s
->flags
& SLAB_STORE_USER
)
497 off
+= 2 * sizeof(struct track
);
500 /* Beginning of the filler is the free pointer */
501 print_section("Padding", p
+ off
, s
->size
- off
);
506 static void object_err(struct kmem_cache
*s
, struct page
*page
,
507 u8
*object
, char *reason
)
510 print_trailer(s
, page
, object
);
513 static void slab_err(struct kmem_cache
*s
, struct page
*page
, char *fmt
, ...)
519 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
522 print_page_info(page
);
526 static void init_object(struct kmem_cache
*s
, void *object
, int active
)
530 if (s
->flags
& __OBJECT_POISON
) {
531 memset(p
, POISON_FREE
, s
->objsize
- 1);
532 p
[s
->objsize
-1] = POISON_END
;
535 if (s
->flags
& SLAB_RED_ZONE
)
536 memset(p
+ s
->objsize
,
537 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
,
538 s
->inuse
- s
->objsize
);
541 static u8
*check_bytes(u8
*start
, unsigned int value
, unsigned int bytes
)
544 if (*start
!= (u8
)value
)
552 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
553 void *from
, void *to
)
555 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
556 memset(from
, data
, to
- from
);
559 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
560 u8
*object
, char *what
,
561 u8
* start
, unsigned int value
, unsigned int bytes
)
566 fault
= check_bytes(start
, value
, bytes
);
571 while (end
> fault
&& end
[-1] == value
)
574 slab_bug(s
, "%s overwritten", what
);
575 printk(KERN_ERR
"INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
576 fault
, end
- 1, fault
[0], value
);
577 print_trailer(s
, page
, object
);
579 restore_bytes(s
, what
, value
, fault
, end
);
587 * Bytes of the object to be managed.
588 * If the freepointer may overlay the object then the free
589 * pointer is the first word of the object.
591 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
594 * object + s->objsize
595 * Padding to reach word boundary. This is also used for Redzoning.
596 * Padding is extended by another word if Redzoning is enabled and
599 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
600 * 0xcc (RED_ACTIVE) for objects in use.
603 * Meta data starts here.
605 * A. Free pointer (if we cannot overwrite object on free)
606 * B. Tracking data for SLAB_STORE_USER
607 * C. Padding to reach required alignment boundary or at mininum
608 * one word if debuggin is on to be able to detect writes
609 * before the word boundary.
611 * Padding is done using 0x5a (POISON_INUSE)
614 * Nothing is used beyond s->size.
616 * If slabcaches are merged then the objsize and inuse boundaries are mostly
617 * ignored. And therefore no slab options that rely on these boundaries
618 * may be used with merged slabcaches.
621 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
623 unsigned long off
= s
->inuse
; /* The end of info */
626 /* Freepointer is placed after the object. */
627 off
+= sizeof(void *);
629 if (s
->flags
& SLAB_STORE_USER
)
630 /* We also have user information there */
631 off
+= 2 * sizeof(struct track
);
636 return check_bytes_and_report(s
, page
, p
, "Object padding",
637 p
+ off
, POISON_INUSE
, s
->size
- off
);
640 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
648 if (!(s
->flags
& SLAB_POISON
))
651 start
= page_address(page
);
652 end
= start
+ (PAGE_SIZE
<< s
->order
);
653 length
= s
->objects
* s
->size
;
654 remainder
= end
- (start
+ length
);
658 fault
= check_bytes(start
+ length
, POISON_INUSE
, remainder
);
661 while (end
> fault
&& end
[-1] == POISON_INUSE
)
664 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
665 print_section("Padding", start
, length
);
667 restore_bytes(s
, "slab padding", POISON_INUSE
, start
, end
);
671 static int check_object(struct kmem_cache
*s
, struct page
*page
,
672 void *object
, int active
)
675 u8
*endobject
= object
+ s
->objsize
;
677 if (s
->flags
& SLAB_RED_ZONE
) {
679 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
;
681 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
682 endobject
, red
, s
->inuse
- s
->objsize
))
685 if ((s
->flags
& SLAB_POISON
) && s
->objsize
< s
->inuse
)
686 check_bytes_and_report(s
, page
, p
, "Alignment padding", endobject
,
687 POISON_INUSE
, s
->inuse
- s
->objsize
);
690 if (s
->flags
& SLAB_POISON
) {
691 if (!active
&& (s
->flags
& __OBJECT_POISON
) &&
692 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
693 POISON_FREE
, s
->objsize
- 1) ||
694 !check_bytes_and_report(s
, page
, p
, "Poison",
695 p
+ s
->objsize
-1, POISON_END
, 1)))
698 * check_pad_bytes cleans up on its own.
700 check_pad_bytes(s
, page
, p
);
703 if (!s
->offset
&& active
)
705 * Object and freepointer overlap. Cannot check
706 * freepointer while object is allocated.
710 /* Check free pointer validity */
711 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
712 object_err(s
, page
, p
, "Freepointer corrupt");
714 * No choice but to zap it and thus loose the remainder
715 * of the free objects in this slab. May cause
716 * another error because the object count is now wrong.
718 set_freepointer(s
, p
, NULL
);
724 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
726 VM_BUG_ON(!irqs_disabled());
728 if (!PageSlab(page
)) {
729 slab_err(s
, page
, "Not a valid slab page");
732 if (page
->offset
* sizeof(void *) != s
->offset
) {
733 slab_err(s
, page
, "Corrupted offset %lu",
734 (unsigned long)(page
->offset
* sizeof(void *)));
737 if (page
->inuse
> s
->objects
) {
738 slab_err(s
, page
, "inuse %u > max %u",
739 s
->name
, page
->inuse
, s
->objects
);
742 /* Slab_pad_check fixes things up after itself */
743 slab_pad_check(s
, page
);
748 * Determine if a certain object on a page is on the freelist. Must hold the
749 * slab lock to guarantee that the chains are in a consistent state.
751 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
754 void *fp
= page
->freelist
;
757 while (fp
&& nr
<= s
->objects
) {
760 if (!check_valid_pointer(s
, page
, fp
)) {
762 object_err(s
, page
, object
,
763 "Freechain corrupt");
764 set_freepointer(s
, object
, NULL
);
767 slab_err(s
, page
, "Freepointer corrupt");
768 page
->freelist
= NULL
;
769 page
->inuse
= s
->objects
;
770 slab_fix(s
, "Freelist cleared");
776 fp
= get_freepointer(s
, object
);
780 if (page
->inuse
!= s
->objects
- nr
) {
781 slab_err(s
, page
, "Wrong object count. Counter is %d but "
782 "counted were %d", page
->inuse
, s
->objects
- nr
);
783 page
->inuse
= s
->objects
- nr
;
784 slab_fix(s
, "Object count adjusted.");
786 return search
== NULL
;
789 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
, int alloc
)
791 if (s
->flags
& SLAB_TRACE
) {
792 printk(KERN_INFO
"TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
794 alloc
? "alloc" : "free",
799 print_section("Object", (void *)object
, s
->objsize
);
806 * Tracking of fully allocated slabs for debugging purposes.
808 static void add_full(struct kmem_cache_node
*n
, struct page
*page
)
810 spin_lock(&n
->list_lock
);
811 list_add(&page
->lru
, &n
->full
);
812 spin_unlock(&n
->list_lock
);
815 static void remove_full(struct kmem_cache
*s
, struct page
*page
)
817 struct kmem_cache_node
*n
;
819 if (!(s
->flags
& SLAB_STORE_USER
))
822 n
= get_node(s
, page_to_nid(page
));
824 spin_lock(&n
->list_lock
);
825 list_del(&page
->lru
);
826 spin_unlock(&n
->list_lock
);
829 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
832 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
835 init_object(s
, object
, 0);
836 init_tracking(s
, object
);
839 static int alloc_debug_processing(struct kmem_cache
*s
, struct page
*page
,
840 void *object
, void *addr
)
842 if (!check_slab(s
, page
))
845 if (object
&& !on_freelist(s
, page
, object
)) {
846 object_err(s
, page
, object
, "Object already allocated");
850 if (!check_valid_pointer(s
, page
, object
)) {
851 object_err(s
, page
, object
, "Freelist Pointer check fails");
855 if (object
&& !check_object(s
, page
, object
, 0))
858 /* Success perform special debug activities for allocs */
859 if (s
->flags
& SLAB_STORE_USER
)
860 set_track(s
, object
, TRACK_ALLOC
, addr
);
861 trace(s
, page
, object
, 1);
862 init_object(s
, object
, 1);
866 if (PageSlab(page
)) {
868 * If this is a slab page then lets do the best we can
869 * to avoid issues in the future. Marking all objects
870 * as used avoids touching the remaining objects.
872 slab_fix(s
, "Marking all objects used");
873 page
->inuse
= s
->objects
;
874 page
->freelist
= NULL
;
875 /* Fix up fields that may be corrupted */
876 page
->offset
= s
->offset
/ sizeof(void *);
881 static int free_debug_processing(struct kmem_cache
*s
, struct page
*page
,
882 void *object
, void *addr
)
884 if (!check_slab(s
, page
))
887 if (!check_valid_pointer(s
, page
, object
)) {
888 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
892 if (on_freelist(s
, page
, object
)) {
893 object_err(s
, page
, object
, "Object already free");
897 if (!check_object(s
, page
, object
, 1))
900 if (unlikely(s
!= page
->slab
)) {
902 slab_err(s
, page
, "Attempt to free object(0x%p) "
903 "outside of slab", object
);
907 "SLUB <none>: no slab for object 0x%p.\n",
912 object_err(s
, page
, object
,
913 "page slab pointer corrupt.");
917 /* Special debug activities for freeing objects */
918 if (!SlabFrozen(page
) && !page
->freelist
)
919 remove_full(s
, page
);
920 if (s
->flags
& SLAB_STORE_USER
)
921 set_track(s
, object
, TRACK_FREE
, addr
);
922 trace(s
, page
, object
, 0);
923 init_object(s
, object
, 0);
927 slab_fix(s
, "Object at 0x%p not freed", object
);
931 static int __init
setup_slub_debug(char *str
)
933 slub_debug
= DEBUG_DEFAULT_FLAGS
;
934 if (*str
++ != '=' || !*str
)
936 * No options specified. Switch on full debugging.
942 * No options but restriction on slabs. This means full
943 * debugging for slabs matching a pattern.
950 * Switch off all debugging measures.
955 * Determine which debug features should be switched on
957 for ( ;*str
&& *str
!= ','; str
++) {
958 switch (tolower(*str
)) {
960 slub_debug
|= SLAB_DEBUG_FREE
;
963 slub_debug
|= SLAB_RED_ZONE
;
966 slub_debug
|= SLAB_POISON
;
969 slub_debug
|= SLAB_STORE_USER
;
972 slub_debug
|= SLAB_TRACE
;
975 printk(KERN_ERR
"slub_debug option '%c' "
976 "unknown. skipped\n",*str
);
982 slub_debug_slabs
= str
+ 1;
987 __setup("slub_debug", setup_slub_debug
);
989 static unsigned long kmem_cache_flags(unsigned long objsize
,
990 unsigned long flags
, const char *name
,
991 void (*ctor
)(void *, struct kmem_cache
*, unsigned long))
994 * The page->offset field is only 16 bit wide. This is an offset
995 * in units of words from the beginning of an object. If the slab
996 * size is bigger then we cannot move the free pointer behind the
999 * On 32 bit platforms the limit is 256k. On 64bit platforms
1000 * the limit is 512k.
1002 * Debugging or ctor may create a need to move the free
1003 * pointer. Fail if this happens.
1005 if (objsize
>= 65535 * sizeof(void *)) {
1006 BUG_ON(flags
& (SLAB_RED_ZONE
| SLAB_POISON
|
1007 SLAB_STORE_USER
| SLAB_DESTROY_BY_RCU
));
1011 * Enable debugging if selected on the kernel commandline.
1013 if (slub_debug
&& (!slub_debug_slabs
||
1014 strncmp(slub_debug_slabs
, name
,
1015 strlen(slub_debug_slabs
)) == 0))
1016 flags
|= slub_debug
;
1022 static inline void setup_object_debug(struct kmem_cache
*s
,
1023 struct page
*page
, void *object
) {}
1025 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1026 struct page
*page
, void *object
, void *addr
) { return 0; }
1028 static inline int free_debug_processing(struct kmem_cache
*s
,
1029 struct page
*page
, void *object
, void *addr
) { return 0; }
1031 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1033 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1034 void *object
, int active
) { return 1; }
1035 static inline void add_full(struct kmem_cache_node
*n
, struct page
*page
) {}
1036 static inline unsigned long kmem_cache_flags(unsigned long objsize
,
1037 unsigned long flags
, const char *name
,
1038 void (*ctor
)(void *, struct kmem_cache
*, unsigned long))
1042 #define slub_debug 0
1045 * Slab allocation and freeing
1047 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1050 int pages
= 1 << s
->order
;
1053 flags
|= __GFP_COMP
;
1055 if (s
->flags
& SLAB_CACHE_DMA
)
1058 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
1059 flags
|= __GFP_RECLAIMABLE
;
1062 page
= alloc_pages(flags
, s
->order
);
1064 page
= alloc_pages_node(node
, flags
, s
->order
);
1069 mod_zone_page_state(page_zone(page
),
1070 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1071 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1077 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1080 setup_object_debug(s
, page
, object
);
1081 if (unlikely(s
->ctor
))
1082 s
->ctor(object
, s
, 0);
1085 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1088 struct kmem_cache_node
*n
;
1094 BUG_ON(flags
& GFP_SLAB_BUG_MASK
);
1096 if (flags
& __GFP_WAIT
)
1099 page
= allocate_slab(s
,
1100 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1104 n
= get_node(s
, page_to_nid(page
));
1106 atomic_long_inc(&n
->nr_slabs
);
1107 page
->offset
= s
->offset
/ sizeof(void *);
1109 page
->flags
|= 1 << PG_slab
;
1110 if (s
->flags
& (SLAB_DEBUG_FREE
| SLAB_RED_ZONE
| SLAB_POISON
|
1111 SLAB_STORE_USER
| SLAB_TRACE
))
1114 start
= page_address(page
);
1115 end
= start
+ s
->objects
* s
->size
;
1117 if (unlikely(s
->flags
& SLAB_POISON
))
1118 memset(start
, POISON_INUSE
, PAGE_SIZE
<< s
->order
);
1121 for_each_object(p
, s
, start
) {
1122 setup_object(s
, page
, last
);
1123 set_freepointer(s
, last
, p
);
1126 setup_object(s
, page
, last
);
1127 set_freepointer(s
, last
, NULL
);
1129 page
->freelist
= start
;
1130 page
->lockless_freelist
= NULL
;
1133 if (flags
& __GFP_WAIT
)
1134 local_irq_disable();
1138 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1140 int pages
= 1 << s
->order
;
1142 if (unlikely(SlabDebug(page
))) {
1145 slab_pad_check(s
, page
);
1146 for_each_object(p
, s
, page_address(page
))
1147 check_object(s
, page
, p
, 0);
1148 ClearSlabDebug(page
);
1151 mod_zone_page_state(page_zone(page
),
1152 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1153 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1156 page
->mapping
= NULL
;
1157 __free_pages(page
, s
->order
);
1160 static void rcu_free_slab(struct rcu_head
*h
)
1164 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1165 __free_slab(page
->slab
, page
);
1168 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1170 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1172 * RCU free overloads the RCU head over the LRU
1174 struct rcu_head
*head
= (void *)&page
->lru
;
1176 call_rcu(head
, rcu_free_slab
);
1178 __free_slab(s
, page
);
1181 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1183 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1185 atomic_long_dec(&n
->nr_slabs
);
1186 reset_page_mapcount(page
);
1187 __ClearPageSlab(page
);
1192 * Per slab locking using the pagelock
1194 static __always_inline
void slab_lock(struct page
*page
)
1196 bit_spin_lock(PG_locked
, &page
->flags
);
1199 static __always_inline
void slab_unlock(struct page
*page
)
1201 bit_spin_unlock(PG_locked
, &page
->flags
);
1204 static __always_inline
int slab_trylock(struct page
*page
)
1208 rc
= bit_spin_trylock(PG_locked
, &page
->flags
);
1213 * Management of partially allocated slabs
1215 static void add_partial_tail(struct kmem_cache_node
*n
, struct page
*page
)
1217 spin_lock(&n
->list_lock
);
1219 list_add_tail(&page
->lru
, &n
->partial
);
1220 spin_unlock(&n
->list_lock
);
1223 static void add_partial(struct kmem_cache_node
*n
, struct page
*page
)
1225 spin_lock(&n
->list_lock
);
1227 list_add(&page
->lru
, &n
->partial
);
1228 spin_unlock(&n
->list_lock
);
1231 static void remove_partial(struct kmem_cache
*s
,
1234 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1236 spin_lock(&n
->list_lock
);
1237 list_del(&page
->lru
);
1239 spin_unlock(&n
->list_lock
);
1243 * Lock slab and remove from the partial list.
1245 * Must hold list_lock.
1247 static inline int lock_and_freeze_slab(struct kmem_cache_node
*n
, struct page
*page
)
1249 if (slab_trylock(page
)) {
1250 list_del(&page
->lru
);
1252 SetSlabFrozen(page
);
1259 * Try to allocate a partial slab from a specific node.
1261 static struct page
*get_partial_node(struct kmem_cache_node
*n
)
1266 * Racy check. If we mistakenly see no partial slabs then we
1267 * just allocate an empty slab. If we mistakenly try to get a
1268 * partial slab and there is none available then get_partials()
1271 if (!n
|| !n
->nr_partial
)
1274 spin_lock(&n
->list_lock
);
1275 list_for_each_entry(page
, &n
->partial
, lru
)
1276 if (lock_and_freeze_slab(n
, page
))
1280 spin_unlock(&n
->list_lock
);
1285 * Get a page from somewhere. Search in increasing NUMA distances.
1287 static struct page
*get_any_partial(struct kmem_cache
*s
, gfp_t flags
)
1290 struct zonelist
*zonelist
;
1295 * The defrag ratio allows a configuration of the tradeoffs between
1296 * inter node defragmentation and node local allocations. A lower
1297 * defrag_ratio increases the tendency to do local allocations
1298 * instead of attempting to obtain partial slabs from other nodes.
1300 * If the defrag_ratio is set to 0 then kmalloc() always
1301 * returns node local objects. If the ratio is higher then kmalloc()
1302 * may return off node objects because partial slabs are obtained
1303 * from other nodes and filled up.
1305 * If /sys/slab/xx/defrag_ratio is set to 100 (which makes
1306 * defrag_ratio = 1000) then every (well almost) allocation will
1307 * first attempt to defrag slab caches on other nodes. This means
1308 * scanning over all nodes to look for partial slabs which may be
1309 * expensive if we do it every time we are trying to find a slab
1310 * with available objects.
1312 if (!s
->defrag_ratio
|| get_cycles() % 1024 > s
->defrag_ratio
)
1315 zonelist
= &NODE_DATA(slab_node(current
->mempolicy
))
1316 ->node_zonelists
[gfp_zone(flags
)];
1317 for (z
= zonelist
->zones
; *z
; z
++) {
1318 struct kmem_cache_node
*n
;
1320 n
= get_node(s
, zone_to_nid(*z
));
1322 if (n
&& cpuset_zone_allowed_hardwall(*z
, flags
) &&
1323 n
->nr_partial
> MIN_PARTIAL
) {
1324 page
= get_partial_node(n
);
1334 * Get a partial page, lock it and return it.
1336 static struct page
*get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
)
1339 int searchnode
= (node
== -1) ? numa_node_id() : node
;
1341 page
= get_partial_node(get_node(s
, searchnode
));
1342 if (page
|| (flags
& __GFP_THISNODE
))
1345 return get_any_partial(s
, flags
);
1349 * Move a page back to the lists.
1351 * Must be called with the slab lock held.
1353 * On exit the slab lock will have been dropped.
1355 static void unfreeze_slab(struct kmem_cache
*s
, struct page
*page
)
1357 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1359 ClearSlabFrozen(page
);
1363 add_partial(n
, page
);
1364 else if (SlabDebug(page
) && (s
->flags
& SLAB_STORE_USER
))
1369 if (n
->nr_partial
< MIN_PARTIAL
) {
1371 * Adding an empty slab to the partial slabs in order
1372 * to avoid page allocator overhead. This slab needs
1373 * to come after the other slabs with objects in
1374 * order to fill them up. That way the size of the
1375 * partial list stays small. kmem_cache_shrink can
1376 * reclaim empty slabs from the partial list.
1378 add_partial_tail(n
, page
);
1382 discard_slab(s
, page
);
1388 * Remove the cpu slab
1390 static void deactivate_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1392 struct page
*page
= c
->page
;
1394 * Merge cpu freelist into freelist. Typically we get here
1395 * because both freelists are empty. So this is unlikely
1398 while (unlikely(c
->freelist
)) {
1401 /* Retrieve object from cpu_freelist */
1402 object
= c
->freelist
;
1403 c
->freelist
= c
->freelist
[page
->offset
];
1405 /* And put onto the regular freelist */
1406 object
[page
->offset
] = page
->freelist
;
1407 page
->freelist
= object
;
1411 unfreeze_slab(s
, page
);
1414 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1417 deactivate_slab(s
, c
);
1422 * Called from IPI handler with interrupts disabled.
1424 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
1426 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
1428 if (likely(c
&& c
->page
))
1432 static void flush_cpu_slab(void *d
)
1434 struct kmem_cache
*s
= d
;
1436 __flush_cpu_slab(s
, smp_processor_id());
1439 static void flush_all(struct kmem_cache
*s
)
1442 on_each_cpu(flush_cpu_slab
, s
, 1, 1);
1444 unsigned long flags
;
1446 local_irq_save(flags
);
1448 local_irq_restore(flags
);
1453 * Check if the objects in a per cpu structure fit numa
1454 * locality expectations.
1456 static inline int node_match(struct kmem_cache_cpu
*c
, int node
)
1459 if (node
!= -1 && c
->node
!= node
)
1466 * Slow path. The lockless freelist is empty or we need to perform
1469 * Interrupts are disabled.
1471 * Processing is still very fast if new objects have been freed to the
1472 * regular freelist. In that case we simply take over the regular freelist
1473 * as the lockless freelist and zap the regular freelist.
1475 * If that is not working then we fall back to the partial lists. We take the
1476 * first element of the freelist as the object to allocate now and move the
1477 * rest of the freelist to the lockless freelist.
1479 * And if we were unable to get a new slab from the partial slab lists then
1480 * we need to allocate a new slab. This is slowest path since we may sleep.
1482 static void *__slab_alloc(struct kmem_cache
*s
,
1483 gfp_t gfpflags
, int node
, void *addr
, struct kmem_cache_cpu
*c
)
1492 if (unlikely(!node_match(c
, node
)))
1495 object
= c
->page
->freelist
;
1496 if (unlikely(!object
))
1498 if (unlikely(SlabDebug(c
->page
)))
1501 object
= c
->page
->freelist
;
1502 c
->freelist
= object
[c
->page
->offset
];
1503 c
->page
->inuse
= s
->objects
;
1504 c
->page
->freelist
= NULL
;
1505 c
->node
= page_to_nid(c
->page
);
1506 slab_unlock(c
->page
);
1510 deactivate_slab(s
, c
);
1513 new = get_partial(s
, gfpflags
, node
);
1519 new = new_slab(s
, gfpflags
, node
);
1521 c
= get_cpu_slab(s
, smp_processor_id());
1524 * Someone else populated the cpu_slab while we
1525 * enabled interrupts, or we have gotten scheduled
1526 * on another cpu. The page may not be on the
1527 * requested node even if __GFP_THISNODE was
1528 * specified. So we need to recheck.
1530 if (node_match(c
, node
)) {
1532 * Current cpuslab is acceptable and we
1533 * want the current one since its cache hot
1535 discard_slab(s
, new);
1539 /* New slab does not fit our expectations */
1549 object
= c
->page
->freelist
;
1550 if (!alloc_debug_processing(s
, c
->page
, object
, addr
))
1554 c
->page
->freelist
= object
[c
->page
->offset
];
1555 slab_unlock(c
->page
);
1560 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1561 * have the fastpath folded into their functions. So no function call
1562 * overhead for requests that can be satisfied on the fastpath.
1564 * The fastpath works by first checking if the lockless freelist can be used.
1565 * If not then __slab_alloc is called for slow processing.
1567 * Otherwise we can simply pick the next object from the lockless free list.
1569 static void __always_inline
*slab_alloc(struct kmem_cache
*s
,
1570 gfp_t gfpflags
, int node
, void *addr
)
1573 unsigned long flags
;
1574 struct kmem_cache_cpu
*c
;
1576 local_irq_save(flags
);
1577 c
= get_cpu_slab(s
, smp_processor_id());
1578 if (unlikely(!c
->page
|| !c
->freelist
||
1579 !node_match(c
, node
)))
1581 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
1584 object
= c
->freelist
;
1585 c
->freelist
= object
[c
->page
->offset
];
1587 local_irq_restore(flags
);
1589 if (unlikely((gfpflags
& __GFP_ZERO
) && object
))
1590 memset(object
, 0, s
->objsize
);
1595 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
1597 return slab_alloc(s
, gfpflags
, -1, __builtin_return_address(0));
1599 EXPORT_SYMBOL(kmem_cache_alloc
);
1602 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
1604 return slab_alloc(s
, gfpflags
, node
, __builtin_return_address(0));
1606 EXPORT_SYMBOL(kmem_cache_alloc_node
);
1610 * Slow patch handling. This may still be called frequently since objects
1611 * have a longer lifetime than the cpu slabs in most processing loads.
1613 * So we still attempt to reduce cache line usage. Just take the slab
1614 * lock and free the item. If there is no additional partial page
1615 * handling required then we can return immediately.
1617 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
1618 void *x
, void *addr
)
1621 void **object
= (void *)x
;
1625 if (unlikely(SlabDebug(page
)))
1628 prior
= object
[page
->offset
] = page
->freelist
;
1629 page
->freelist
= object
;
1632 if (unlikely(SlabFrozen(page
)))
1635 if (unlikely(!page
->inuse
))
1639 * Objects left in the slab. If it
1640 * was not on the partial list before
1643 if (unlikely(!prior
))
1644 add_partial(get_node(s
, page_to_nid(page
)), page
);
1653 * Slab still on the partial list.
1655 remove_partial(s
, page
);
1658 discard_slab(s
, page
);
1662 if (!free_debug_processing(s
, page
, x
, addr
))
1668 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1669 * can perform fastpath freeing without additional function calls.
1671 * The fastpath is only possible if we are freeing to the current cpu slab
1672 * of this processor. This typically the case if we have just allocated
1675 * If fastpath is not possible then fall back to __slab_free where we deal
1676 * with all sorts of special processing.
1678 static void __always_inline
slab_free(struct kmem_cache
*s
,
1679 struct page
*page
, void *x
, void *addr
)
1681 void **object
= (void *)x
;
1682 unsigned long flags
;
1683 struct kmem_cache_cpu
*c
;
1685 local_irq_save(flags
);
1686 debug_check_no_locks_freed(object
, s
->objsize
);
1687 c
= get_cpu_slab(s
, smp_processor_id());
1688 if (likely(page
== c
->page
&& !SlabDebug(page
))) {
1689 object
[page
->offset
] = c
->freelist
;
1690 c
->freelist
= object
;
1692 __slab_free(s
, page
, x
, addr
);
1694 local_irq_restore(flags
);
1697 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
1701 page
= virt_to_head_page(x
);
1703 slab_free(s
, page
, x
, __builtin_return_address(0));
1705 EXPORT_SYMBOL(kmem_cache_free
);
1707 /* Figure out on which slab object the object resides */
1708 static struct page
*get_object_page(const void *x
)
1710 struct page
*page
= virt_to_head_page(x
);
1712 if (!PageSlab(page
))
1719 * Object placement in a slab is made very easy because we always start at
1720 * offset 0. If we tune the size of the object to the alignment then we can
1721 * get the required alignment by putting one properly sized object after
1724 * Notice that the allocation order determines the sizes of the per cpu
1725 * caches. Each processor has always one slab available for allocations.
1726 * Increasing the allocation order reduces the number of times that slabs
1727 * must be moved on and off the partial lists and is therefore a factor in
1732 * Mininum / Maximum order of slab pages. This influences locking overhead
1733 * and slab fragmentation. A higher order reduces the number of partial slabs
1734 * and increases the number of allocations possible without having to
1735 * take the list_lock.
1737 static int slub_min_order
;
1738 static int slub_max_order
= DEFAULT_MAX_ORDER
;
1739 static int slub_min_objects
= DEFAULT_MIN_OBJECTS
;
1742 * Merge control. If this is set then no merging of slab caches will occur.
1743 * (Could be removed. This was introduced to pacify the merge skeptics.)
1745 static int slub_nomerge
;
1748 * Calculate the order of allocation given an slab object size.
1750 * The order of allocation has significant impact on performance and other
1751 * system components. Generally order 0 allocations should be preferred since
1752 * order 0 does not cause fragmentation in the page allocator. Larger objects
1753 * be problematic to put into order 0 slabs because there may be too much
1754 * unused space left. We go to a higher order if more than 1/8th of the slab
1757 * In order to reach satisfactory performance we must ensure that a minimum
1758 * number of objects is in one slab. Otherwise we may generate too much
1759 * activity on the partial lists which requires taking the list_lock. This is
1760 * less a concern for large slabs though which are rarely used.
1762 * slub_max_order specifies the order where we begin to stop considering the
1763 * number of objects in a slab as critical. If we reach slub_max_order then
1764 * we try to keep the page order as low as possible. So we accept more waste
1765 * of space in favor of a small page order.
1767 * Higher order allocations also allow the placement of more objects in a
1768 * slab and thereby reduce object handling overhead. If the user has
1769 * requested a higher mininum order then we start with that one instead of
1770 * the smallest order which will fit the object.
1772 static inline int slab_order(int size
, int min_objects
,
1773 int max_order
, int fract_leftover
)
1777 int min_order
= slub_min_order
;
1780 * If we would create too many object per slab then reduce
1781 * the slab order even if it goes below slub_min_order.
1783 while (min_order
> 0 &&
1784 (PAGE_SIZE
<< min_order
) >= MAX_OBJECTS_PER_SLAB
* size
)
1787 for (order
= max(min_order
,
1788 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
1789 order
<= max_order
; order
++) {
1791 unsigned long slab_size
= PAGE_SIZE
<< order
;
1793 if (slab_size
< min_objects
* size
)
1796 rem
= slab_size
% size
;
1798 if (rem
<= slab_size
/ fract_leftover
)
1801 /* If the next size is too high then exit now */
1802 if (slab_size
* 2 >= MAX_OBJECTS_PER_SLAB
* size
)
1809 static inline int calculate_order(int size
)
1816 * Attempt to find best configuration for a slab. This
1817 * works by first attempting to generate a layout with
1818 * the best configuration and backing off gradually.
1820 * First we reduce the acceptable waste in a slab. Then
1821 * we reduce the minimum objects required in a slab.
1823 min_objects
= slub_min_objects
;
1824 while (min_objects
> 1) {
1826 while (fraction
>= 4) {
1827 order
= slab_order(size
, min_objects
,
1828 slub_max_order
, fraction
);
1829 if (order
<= slub_max_order
)
1837 * We were unable to place multiple objects in a slab. Now
1838 * lets see if we can place a single object there.
1840 order
= slab_order(size
, 1, slub_max_order
, 1);
1841 if (order
<= slub_max_order
)
1845 * Doh this slab cannot be placed using slub_max_order.
1847 order
= slab_order(size
, 1, MAX_ORDER
, 1);
1848 if (order
<= MAX_ORDER
)
1854 * Figure out what the alignment of the objects will be.
1856 static unsigned long calculate_alignment(unsigned long flags
,
1857 unsigned long align
, unsigned long size
)
1860 * If the user wants hardware cache aligned objects then
1861 * follow that suggestion if the object is sufficiently
1864 * The hardware cache alignment cannot override the
1865 * specified alignment though. If that is greater
1868 if ((flags
& SLAB_HWCACHE_ALIGN
) &&
1869 size
> cache_line_size() / 2)
1870 return max_t(unsigned long, align
, cache_line_size());
1872 if (align
< ARCH_SLAB_MINALIGN
)
1873 return ARCH_SLAB_MINALIGN
;
1875 return ALIGN(align
, sizeof(void *));
1878 static void init_kmem_cache_cpu(struct kmem_cache
*s
,
1879 struct kmem_cache_cpu
*c
)
1886 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
, gfp_t flags
)
1890 for_each_possible_cpu(cpu
)
1891 init_kmem_cache_cpu(s
, get_cpu_slab(s
, cpu
));
1896 static void init_kmem_cache_node(struct kmem_cache_node
*n
)
1899 atomic_long_set(&n
->nr_slabs
, 0);
1900 spin_lock_init(&n
->list_lock
);
1901 INIT_LIST_HEAD(&n
->partial
);
1902 #ifdef CONFIG_SLUB_DEBUG
1903 INIT_LIST_HEAD(&n
->full
);
1909 * No kmalloc_node yet so do it by hand. We know that this is the first
1910 * slab on the node for this slabcache. There are no concurrent accesses
1913 * Note that this function only works on the kmalloc_node_cache
1914 * when allocating for the kmalloc_node_cache.
1916 static struct kmem_cache_node
*early_kmem_cache_node_alloc(gfp_t gfpflags
,
1920 struct kmem_cache_node
*n
;
1922 BUG_ON(kmalloc_caches
->size
< sizeof(struct kmem_cache_node
));
1924 page
= new_slab(kmalloc_caches
, gfpflags
, node
);
1927 if (page_to_nid(page
) != node
) {
1928 printk(KERN_ERR
"SLUB: Unable to allocate memory from "
1930 printk(KERN_ERR
"SLUB: Allocating a useless per node structure "
1931 "in order to be able to continue\n");
1936 page
->freelist
= get_freepointer(kmalloc_caches
, n
);
1938 kmalloc_caches
->node
[node
] = n
;
1939 #ifdef CONFIG_SLUB_DEBUG
1940 init_object(kmalloc_caches
, n
, 1);
1941 init_tracking(kmalloc_caches
, n
);
1943 init_kmem_cache_node(n
);
1944 atomic_long_inc(&n
->nr_slabs
);
1945 add_partial(n
, page
);
1948 * new_slab() disables interupts. If we do not reenable interrupts here
1949 * then bootup would continue with interrupts disabled.
1955 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
1959 for_each_node_state(node
, N_NORMAL_MEMORY
) {
1960 struct kmem_cache_node
*n
= s
->node
[node
];
1961 if (n
&& n
!= &s
->local_node
)
1962 kmem_cache_free(kmalloc_caches
, n
);
1963 s
->node
[node
] = NULL
;
1967 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
1972 if (slab_state
>= UP
)
1973 local_node
= page_to_nid(virt_to_page(s
));
1977 for_each_node_state(node
, N_NORMAL_MEMORY
) {
1978 struct kmem_cache_node
*n
;
1980 if (local_node
== node
)
1983 if (slab_state
== DOWN
) {
1984 n
= early_kmem_cache_node_alloc(gfpflags
,
1988 n
= kmem_cache_alloc_node(kmalloc_caches
,
1992 free_kmem_cache_nodes(s
);
1998 init_kmem_cache_node(n
);
2003 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2007 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
2009 init_kmem_cache_node(&s
->local_node
);
2015 * calculate_sizes() determines the order and the distribution of data within
2018 static int calculate_sizes(struct kmem_cache
*s
)
2020 unsigned long flags
= s
->flags
;
2021 unsigned long size
= s
->objsize
;
2022 unsigned long align
= s
->align
;
2025 * Determine if we can poison the object itself. If the user of
2026 * the slab may touch the object after free or before allocation
2027 * then we should never poison the object itself.
2029 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
2031 s
->flags
|= __OBJECT_POISON
;
2033 s
->flags
&= ~__OBJECT_POISON
;
2036 * Round up object size to the next word boundary. We can only
2037 * place the free pointer at word boundaries and this determines
2038 * the possible location of the free pointer.
2040 size
= ALIGN(size
, sizeof(void *));
2042 #ifdef CONFIG_SLUB_DEBUG
2044 * If we are Redzoning then check if there is some space between the
2045 * end of the object and the free pointer. If not then add an
2046 * additional word to have some bytes to store Redzone information.
2048 if ((flags
& SLAB_RED_ZONE
) && size
== s
->objsize
)
2049 size
+= sizeof(void *);
2053 * With that we have determined the number of bytes in actual use
2054 * by the object. This is the potential offset to the free pointer.
2058 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
2061 * Relocate free pointer after the object if it is not
2062 * permitted to overwrite the first word of the object on
2065 * This is the case if we do RCU, have a constructor or
2066 * destructor or are poisoning the objects.
2069 size
+= sizeof(void *);
2072 #ifdef CONFIG_SLUB_DEBUG
2073 if (flags
& SLAB_STORE_USER
)
2075 * Need to store information about allocs and frees after
2078 size
+= 2 * sizeof(struct track
);
2080 if (flags
& SLAB_RED_ZONE
)
2082 * Add some empty padding so that we can catch
2083 * overwrites from earlier objects rather than let
2084 * tracking information or the free pointer be
2085 * corrupted if an user writes before the start
2088 size
+= sizeof(void *);
2092 * Determine the alignment based on various parameters that the
2093 * user specified and the dynamic determination of cache line size
2096 align
= calculate_alignment(flags
, align
, s
->objsize
);
2099 * SLUB stores one object immediately after another beginning from
2100 * offset 0. In order to align the objects we have to simply size
2101 * each object to conform to the alignment.
2103 size
= ALIGN(size
, align
);
2106 s
->order
= calculate_order(size
);
2111 * Determine the number of objects per slab
2113 s
->objects
= (PAGE_SIZE
<< s
->order
) / size
;
2116 * Verify that the number of objects is within permitted limits.
2117 * The page->inuse field is only 16 bit wide! So we cannot have
2118 * more than 64k objects per slab.
2120 if (!s
->objects
|| s
->objects
> MAX_OBJECTS_PER_SLAB
)
2126 static int kmem_cache_open(struct kmem_cache
*s
, gfp_t gfpflags
,
2127 const char *name
, size_t size
,
2128 size_t align
, unsigned long flags
,
2129 void (*ctor
)(void *, struct kmem_cache
*, unsigned long))
2131 memset(s
, 0, kmem_size
);
2136 s
->flags
= kmem_cache_flags(size
, flags
, name
, ctor
);
2138 if (!calculate_sizes(s
))
2143 s
->defrag_ratio
= 100;
2145 if (!init_kmem_cache_nodes(s
, gfpflags
& ~SLUB_DMA
))
2148 if (alloc_kmem_cache_cpus(s
, gfpflags
& ~SLUB_DMA
))
2151 if (flags
& SLAB_PANIC
)
2152 panic("Cannot create slab %s size=%lu realsize=%u "
2153 "order=%u offset=%u flags=%lx\n",
2154 s
->name
, (unsigned long)size
, s
->size
, s
->order
,
2160 * Check if a given pointer is valid
2162 int kmem_ptr_validate(struct kmem_cache
*s
, const void *object
)
2166 page
= get_object_page(object
);
2168 if (!page
|| s
!= page
->slab
)
2169 /* No slab or wrong slab */
2172 if (!check_valid_pointer(s
, page
, object
))
2176 * We could also check if the object is on the slabs freelist.
2177 * But this would be too expensive and it seems that the main
2178 * purpose of kmem_ptr_valid is to check if the object belongs
2179 * to a certain slab.
2183 EXPORT_SYMBOL(kmem_ptr_validate
);
2186 * Determine the size of a slab object
2188 unsigned int kmem_cache_size(struct kmem_cache
*s
)
2192 EXPORT_SYMBOL(kmem_cache_size
);
2194 const char *kmem_cache_name(struct kmem_cache
*s
)
2198 EXPORT_SYMBOL(kmem_cache_name
);
2201 * Attempt to free all slabs on a node. Return the number of slabs we
2202 * were unable to free.
2204 static int free_list(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
2205 struct list_head
*list
)
2207 int slabs_inuse
= 0;
2208 unsigned long flags
;
2209 struct page
*page
, *h
;
2211 spin_lock_irqsave(&n
->list_lock
, flags
);
2212 list_for_each_entry_safe(page
, h
, list
, lru
)
2214 list_del(&page
->lru
);
2215 discard_slab(s
, page
);
2218 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2223 * Release all resources used by a slab cache.
2225 static inline int kmem_cache_close(struct kmem_cache
*s
)
2231 /* Attempt to free all objects */
2232 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2233 struct kmem_cache_node
*n
= get_node(s
, node
);
2235 n
->nr_partial
-= free_list(s
, n
, &n
->partial
);
2236 if (atomic_long_read(&n
->nr_slabs
))
2239 free_kmem_cache_nodes(s
);
2244 * Close a cache and release the kmem_cache structure
2245 * (must be used for caches created using kmem_cache_create)
2247 void kmem_cache_destroy(struct kmem_cache
*s
)
2249 down_write(&slub_lock
);
2253 up_write(&slub_lock
);
2254 if (kmem_cache_close(s
))
2256 sysfs_slab_remove(s
);
2259 up_write(&slub_lock
);
2261 EXPORT_SYMBOL(kmem_cache_destroy
);
2263 /********************************************************************
2265 *******************************************************************/
2267 struct kmem_cache kmalloc_caches
[PAGE_SHIFT
] __cacheline_aligned
;
2268 EXPORT_SYMBOL(kmalloc_caches
);
2270 #ifdef CONFIG_ZONE_DMA
2271 static struct kmem_cache
*kmalloc_caches_dma
[PAGE_SHIFT
];
2274 static int __init
setup_slub_min_order(char *str
)
2276 get_option (&str
, &slub_min_order
);
2281 __setup("slub_min_order=", setup_slub_min_order
);
2283 static int __init
setup_slub_max_order(char *str
)
2285 get_option (&str
, &slub_max_order
);
2290 __setup("slub_max_order=", setup_slub_max_order
);
2292 static int __init
setup_slub_min_objects(char *str
)
2294 get_option (&str
, &slub_min_objects
);
2299 __setup("slub_min_objects=", setup_slub_min_objects
);
2301 static int __init
setup_slub_nomerge(char *str
)
2307 __setup("slub_nomerge", setup_slub_nomerge
);
2309 static struct kmem_cache
*create_kmalloc_cache(struct kmem_cache
*s
,
2310 const char *name
, int size
, gfp_t gfp_flags
)
2312 unsigned int flags
= 0;
2314 if (gfp_flags
& SLUB_DMA
)
2315 flags
= SLAB_CACHE_DMA
;
2317 down_write(&slub_lock
);
2318 if (!kmem_cache_open(s
, gfp_flags
, name
, size
, ARCH_KMALLOC_MINALIGN
,
2322 list_add(&s
->list
, &slab_caches
);
2323 up_write(&slub_lock
);
2324 if (sysfs_slab_add(s
))
2329 panic("Creation of kmalloc slab %s size=%d failed.\n", name
, size
);
2332 #ifdef CONFIG_ZONE_DMA
2334 static void sysfs_add_func(struct work_struct
*w
)
2336 struct kmem_cache
*s
;
2338 down_write(&slub_lock
);
2339 list_for_each_entry(s
, &slab_caches
, list
) {
2340 if (s
->flags
& __SYSFS_ADD_DEFERRED
) {
2341 s
->flags
&= ~__SYSFS_ADD_DEFERRED
;
2345 up_write(&slub_lock
);
2348 static DECLARE_WORK(sysfs_add_work
, sysfs_add_func
);
2350 static noinline
struct kmem_cache
*dma_kmalloc_cache(int index
, gfp_t flags
)
2352 struct kmem_cache
*s
;
2356 s
= kmalloc_caches_dma
[index
];
2360 /* Dynamically create dma cache */
2361 if (flags
& __GFP_WAIT
)
2362 down_write(&slub_lock
);
2364 if (!down_write_trylock(&slub_lock
))
2368 if (kmalloc_caches_dma
[index
])
2371 realsize
= kmalloc_caches
[index
].objsize
;
2372 text
= kasprintf(flags
& ~SLUB_DMA
, "kmalloc_dma-%d", (unsigned int)realsize
),
2373 s
= kmalloc(kmem_size
, flags
& ~SLUB_DMA
);
2375 if (!s
|| !text
|| !kmem_cache_open(s
, flags
, text
,
2376 realsize
, ARCH_KMALLOC_MINALIGN
,
2377 SLAB_CACHE_DMA
|__SYSFS_ADD_DEFERRED
, NULL
)) {
2383 list_add(&s
->list
, &slab_caches
);
2384 kmalloc_caches_dma
[index
] = s
;
2386 schedule_work(&sysfs_add_work
);
2389 up_write(&slub_lock
);
2391 return kmalloc_caches_dma
[index
];
2396 * Conversion table for small slabs sizes / 8 to the index in the
2397 * kmalloc array. This is necessary for slabs < 192 since we have non power
2398 * of two cache sizes there. The size of larger slabs can be determined using
2401 static s8 size_index
[24] = {
2428 static struct kmem_cache
*get_slab(size_t size
, gfp_t flags
)
2434 return ZERO_SIZE_PTR
;
2436 index
= size_index
[(size
- 1) / 8];
2438 index
= fls(size
- 1);
2440 #ifdef CONFIG_ZONE_DMA
2441 if (unlikely((flags
& SLUB_DMA
)))
2442 return dma_kmalloc_cache(index
, flags
);
2445 return &kmalloc_caches
[index
];
2448 void *__kmalloc(size_t size
, gfp_t flags
)
2450 struct kmem_cache
*s
;
2452 if (unlikely(size
> PAGE_SIZE
/ 2))
2453 return (void *)__get_free_pages(flags
| __GFP_COMP
,
2456 s
= get_slab(size
, flags
);
2458 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2461 return slab_alloc(s
, flags
, -1, __builtin_return_address(0));
2463 EXPORT_SYMBOL(__kmalloc
);
2466 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
2468 struct kmem_cache
*s
;
2470 if (unlikely(size
> PAGE_SIZE
/ 2))
2471 return (void *)__get_free_pages(flags
| __GFP_COMP
,
2474 s
= get_slab(size
, flags
);
2476 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2479 return slab_alloc(s
, flags
, node
, __builtin_return_address(0));
2481 EXPORT_SYMBOL(__kmalloc_node
);
2484 size_t ksize(const void *object
)
2487 struct kmem_cache
*s
;
2490 if (unlikely(object
== ZERO_SIZE_PTR
))
2493 page
= get_object_page(object
);
2499 * Debugging requires use of the padding between object
2500 * and whatever may come after it.
2502 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
2506 * If we have the need to store the freelist pointer
2507 * back there or track user information then we can
2508 * only use the space before that information.
2510 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
2514 * Else we can use all the padding etc for the allocation
2518 EXPORT_SYMBOL(ksize
);
2520 void kfree(const void *x
)
2524 if (unlikely(ZERO_OR_NULL_PTR(x
)))
2527 page
= virt_to_head_page(x
);
2528 if (unlikely(!PageSlab(page
))) {
2532 slab_free(page
->slab
, page
, (void *)x
, __builtin_return_address(0));
2534 EXPORT_SYMBOL(kfree
);
2537 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2538 * the remaining slabs by the number of items in use. The slabs with the
2539 * most items in use come first. New allocations will then fill those up
2540 * and thus they can be removed from the partial lists.
2542 * The slabs with the least items are placed last. This results in them
2543 * being allocated from last increasing the chance that the last objects
2544 * are freed in them.
2546 int kmem_cache_shrink(struct kmem_cache
*s
)
2550 struct kmem_cache_node
*n
;
2553 struct list_head
*slabs_by_inuse
=
2554 kmalloc(sizeof(struct list_head
) * s
->objects
, GFP_KERNEL
);
2555 unsigned long flags
;
2557 if (!slabs_by_inuse
)
2561 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2562 n
= get_node(s
, node
);
2567 for (i
= 0; i
< s
->objects
; i
++)
2568 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
2570 spin_lock_irqsave(&n
->list_lock
, flags
);
2573 * Build lists indexed by the items in use in each slab.
2575 * Note that concurrent frees may occur while we hold the
2576 * list_lock. page->inuse here is the upper limit.
2578 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
2579 if (!page
->inuse
&& slab_trylock(page
)) {
2581 * Must hold slab lock here because slab_free
2582 * may have freed the last object and be
2583 * waiting to release the slab.
2585 list_del(&page
->lru
);
2588 discard_slab(s
, page
);
2590 list_move(&page
->lru
,
2591 slabs_by_inuse
+ page
->inuse
);
2596 * Rebuild the partial list with the slabs filled up most
2597 * first and the least used slabs at the end.
2599 for (i
= s
->objects
- 1; i
>= 0; i
--)
2600 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
2602 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2605 kfree(slabs_by_inuse
);
2608 EXPORT_SYMBOL(kmem_cache_shrink
);
2610 /********************************************************************
2611 * Basic setup of slabs
2612 *******************************************************************/
2614 void __init
kmem_cache_init(void)
2621 * Must first have the slab cache available for the allocations of the
2622 * struct kmem_cache_node's. There is special bootstrap code in
2623 * kmem_cache_open for slab_state == DOWN.
2625 create_kmalloc_cache(&kmalloc_caches
[0], "kmem_cache_node",
2626 sizeof(struct kmem_cache_node
), GFP_KERNEL
);
2627 kmalloc_caches
[0].refcount
= -1;
2631 /* Able to allocate the per node structures */
2632 slab_state
= PARTIAL
;
2634 /* Caches that are not of the two-to-the-power-of size */
2635 if (KMALLOC_MIN_SIZE
<= 64) {
2636 create_kmalloc_cache(&kmalloc_caches
[1],
2637 "kmalloc-96", 96, GFP_KERNEL
);
2640 if (KMALLOC_MIN_SIZE
<= 128) {
2641 create_kmalloc_cache(&kmalloc_caches
[2],
2642 "kmalloc-192", 192, GFP_KERNEL
);
2646 for (i
= KMALLOC_SHIFT_LOW
; i
< PAGE_SHIFT
; i
++) {
2647 create_kmalloc_cache(&kmalloc_caches
[i
],
2648 "kmalloc", 1 << i
, GFP_KERNEL
);
2654 * Patch up the size_index table if we have strange large alignment
2655 * requirements for the kmalloc array. This is only the case for
2656 * mips it seems. The standard arches will not generate any code here.
2658 * Largest permitted alignment is 256 bytes due to the way we
2659 * handle the index determination for the smaller caches.
2661 * Make sure that nothing crazy happens if someone starts tinkering
2662 * around with ARCH_KMALLOC_MINALIGN
2664 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 256 ||
2665 (KMALLOC_MIN_SIZE
& (KMALLOC_MIN_SIZE
- 1)));
2667 for (i
= 8; i
< KMALLOC_MIN_SIZE
; i
+= 8)
2668 size_index
[(i
- 1) / 8] = KMALLOC_SHIFT_LOW
;
2672 /* Provide the correct kmalloc names now that the caches are up */
2673 for (i
= KMALLOC_SHIFT_LOW
; i
< PAGE_SHIFT
; i
++)
2674 kmalloc_caches
[i
]. name
=
2675 kasprintf(GFP_KERNEL
, "kmalloc-%d", 1 << i
);
2678 register_cpu_notifier(&slab_notifier
);
2681 kmem_size
= offsetof(struct kmem_cache
, cpu_slab
) +
2682 nr_cpu_ids
* sizeof(struct kmem_cache_cpu
);
2684 printk(KERN_INFO
"SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
2685 " CPUs=%d, Nodes=%d\n",
2686 caches
, cache_line_size(),
2687 slub_min_order
, slub_max_order
, slub_min_objects
,
2688 nr_cpu_ids
, nr_node_ids
);
2692 * Find a mergeable slab cache
2694 static int slab_unmergeable(struct kmem_cache
*s
)
2696 if (slub_nomerge
|| (s
->flags
& SLUB_NEVER_MERGE
))
2703 * We may have set a slab to be unmergeable during bootstrap.
2705 if (s
->refcount
< 0)
2711 static struct kmem_cache
*find_mergeable(size_t size
,
2712 size_t align
, unsigned long flags
, const char *name
,
2713 void (*ctor
)(void *, struct kmem_cache
*, unsigned long))
2715 struct kmem_cache
*s
;
2717 if (slub_nomerge
|| (flags
& SLUB_NEVER_MERGE
))
2723 size
= ALIGN(size
, sizeof(void *));
2724 align
= calculate_alignment(flags
, align
, size
);
2725 size
= ALIGN(size
, align
);
2726 flags
= kmem_cache_flags(size
, flags
, name
, NULL
);
2728 list_for_each_entry(s
, &slab_caches
, list
) {
2729 if (slab_unmergeable(s
))
2735 if ((flags
& SLUB_MERGE_SAME
) != (s
->flags
& SLUB_MERGE_SAME
))
2738 * Check if alignment is compatible.
2739 * Courtesy of Adrian Drzewiecki
2741 if ((s
->size
& ~(align
-1)) != s
->size
)
2744 if (s
->size
- size
>= sizeof(void *))
2752 struct kmem_cache
*kmem_cache_create(const char *name
, size_t size
,
2753 size_t align
, unsigned long flags
,
2754 void (*ctor
)(void *, struct kmem_cache
*, unsigned long))
2756 struct kmem_cache
*s
;
2758 down_write(&slub_lock
);
2759 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
2763 * Adjust the object sizes so that we clear
2764 * the complete object on kzalloc.
2766 s
->objsize
= max(s
->objsize
, (int)size
);
2767 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
2768 up_write(&slub_lock
);
2769 if (sysfs_slab_alias(s
, name
))
2773 s
= kmalloc(kmem_size
, GFP_KERNEL
);
2775 if (kmem_cache_open(s
, GFP_KERNEL
, name
,
2776 size
, align
, flags
, ctor
)) {
2777 list_add(&s
->list
, &slab_caches
);
2778 up_write(&slub_lock
);
2779 if (sysfs_slab_add(s
))
2785 up_write(&slub_lock
);
2788 if (flags
& SLAB_PANIC
)
2789 panic("Cannot create slabcache %s\n", name
);
2794 EXPORT_SYMBOL(kmem_cache_create
);
2798 * Use the cpu notifier to insure that the cpu slabs are flushed when
2801 static int __cpuinit
slab_cpuup_callback(struct notifier_block
*nfb
,
2802 unsigned long action
, void *hcpu
)
2804 long cpu
= (long)hcpu
;
2805 struct kmem_cache
*s
;
2806 unsigned long flags
;
2809 case CPU_UP_CANCELED
:
2810 case CPU_UP_CANCELED_FROZEN
:
2812 case CPU_DEAD_FROZEN
:
2813 down_read(&slub_lock
);
2814 list_for_each_entry(s
, &slab_caches
, list
) {
2815 local_irq_save(flags
);
2816 __flush_cpu_slab(s
, cpu
);
2817 local_irq_restore(flags
);
2819 up_read(&slub_lock
);
2827 static struct notifier_block __cpuinitdata slab_notifier
=
2828 { &slab_cpuup_callback
, NULL
, 0 };
2832 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, void *caller
)
2834 struct kmem_cache
*s
;
2836 if (unlikely(size
> PAGE_SIZE
/ 2))
2837 return (void *)__get_free_pages(gfpflags
| __GFP_COMP
,
2839 s
= get_slab(size
, gfpflags
);
2841 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2844 return slab_alloc(s
, gfpflags
, -1, caller
);
2847 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
2848 int node
, void *caller
)
2850 struct kmem_cache
*s
;
2852 if (unlikely(size
> PAGE_SIZE
/ 2))
2853 return (void *)__get_free_pages(gfpflags
| __GFP_COMP
,
2855 s
= get_slab(size
, gfpflags
);
2857 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2860 return slab_alloc(s
, gfpflags
, node
, caller
);
2863 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
2864 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
2868 void *addr
= page_address(page
);
2870 if (!check_slab(s
, page
) ||
2871 !on_freelist(s
, page
, NULL
))
2874 /* Now we know that a valid freelist exists */
2875 bitmap_zero(map
, s
->objects
);
2877 for_each_free_object(p
, s
, page
->freelist
) {
2878 set_bit(slab_index(p
, s
, addr
), map
);
2879 if (!check_object(s
, page
, p
, 0))
2883 for_each_object(p
, s
, addr
)
2884 if (!test_bit(slab_index(p
, s
, addr
), map
))
2885 if (!check_object(s
, page
, p
, 1))
2890 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
2893 if (slab_trylock(page
)) {
2894 validate_slab(s
, page
, map
);
2897 printk(KERN_INFO
"SLUB %s: Skipped busy slab 0x%p\n",
2900 if (s
->flags
& DEBUG_DEFAULT_FLAGS
) {
2901 if (!SlabDebug(page
))
2902 printk(KERN_ERR
"SLUB %s: SlabDebug not set "
2903 "on slab 0x%p\n", s
->name
, page
);
2905 if (SlabDebug(page
))
2906 printk(KERN_ERR
"SLUB %s: SlabDebug set on "
2907 "slab 0x%p\n", s
->name
, page
);
2911 static int validate_slab_node(struct kmem_cache
*s
,
2912 struct kmem_cache_node
*n
, unsigned long *map
)
2914 unsigned long count
= 0;
2916 unsigned long flags
;
2918 spin_lock_irqsave(&n
->list_lock
, flags
);
2920 list_for_each_entry(page
, &n
->partial
, lru
) {
2921 validate_slab_slab(s
, page
, map
);
2924 if (count
!= n
->nr_partial
)
2925 printk(KERN_ERR
"SLUB %s: %ld partial slabs counted but "
2926 "counter=%ld\n", s
->name
, count
, n
->nr_partial
);
2928 if (!(s
->flags
& SLAB_STORE_USER
))
2931 list_for_each_entry(page
, &n
->full
, lru
) {
2932 validate_slab_slab(s
, page
, map
);
2935 if (count
!= atomic_long_read(&n
->nr_slabs
))
2936 printk(KERN_ERR
"SLUB: %s %ld slabs counted but "
2937 "counter=%ld\n", s
->name
, count
,
2938 atomic_long_read(&n
->nr_slabs
));
2941 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2945 static long validate_slab_cache(struct kmem_cache
*s
)
2948 unsigned long count
= 0;
2949 unsigned long *map
= kmalloc(BITS_TO_LONGS(s
->objects
) *
2950 sizeof(unsigned long), GFP_KERNEL
);
2956 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2957 struct kmem_cache_node
*n
= get_node(s
, node
);
2959 count
+= validate_slab_node(s
, n
, map
);
2965 #ifdef SLUB_RESILIENCY_TEST
2966 static void resiliency_test(void)
2970 printk(KERN_ERR
"SLUB resiliency testing\n");
2971 printk(KERN_ERR
"-----------------------\n");
2972 printk(KERN_ERR
"A. Corruption after allocation\n");
2974 p
= kzalloc(16, GFP_KERNEL
);
2976 printk(KERN_ERR
"\n1. kmalloc-16: Clobber Redzone/next pointer"
2977 " 0x12->0x%p\n\n", p
+ 16);
2979 validate_slab_cache(kmalloc_caches
+ 4);
2981 /* Hmmm... The next two are dangerous */
2982 p
= kzalloc(32, GFP_KERNEL
);
2983 p
[32 + sizeof(void *)] = 0x34;
2984 printk(KERN_ERR
"\n2. kmalloc-32: Clobber next pointer/next slab"
2985 " 0x34 -> -0x%p\n", p
);
2986 printk(KERN_ERR
"If allocated object is overwritten then not detectable\n\n");
2988 validate_slab_cache(kmalloc_caches
+ 5);
2989 p
= kzalloc(64, GFP_KERNEL
);
2990 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
2992 printk(KERN_ERR
"\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
2994 printk(KERN_ERR
"If allocated object is overwritten then not detectable\n\n");
2995 validate_slab_cache(kmalloc_caches
+ 6);
2997 printk(KERN_ERR
"\nB. Corruption after free\n");
2998 p
= kzalloc(128, GFP_KERNEL
);
3001 printk(KERN_ERR
"1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
3002 validate_slab_cache(kmalloc_caches
+ 7);
3004 p
= kzalloc(256, GFP_KERNEL
);
3007 printk(KERN_ERR
"\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
3008 validate_slab_cache(kmalloc_caches
+ 8);
3010 p
= kzalloc(512, GFP_KERNEL
);
3013 printk(KERN_ERR
"\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
3014 validate_slab_cache(kmalloc_caches
+ 9);
3017 static void resiliency_test(void) {};
3021 * Generate lists of code addresses where slabcache objects are allocated
3026 unsigned long count
;
3039 unsigned long count
;
3040 struct location
*loc
;
3043 static void free_loc_track(struct loc_track
*t
)
3046 free_pages((unsigned long)t
->loc
,
3047 get_order(sizeof(struct location
) * t
->max
));
3050 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
3055 order
= get_order(sizeof(struct location
) * max
);
3057 l
= (void *)__get_free_pages(flags
, order
);
3062 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
3070 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
3071 const struct track
*track
)
3073 long start
, end
, pos
;
3076 unsigned long age
= jiffies
- track
->when
;
3082 pos
= start
+ (end
- start
+ 1) / 2;
3085 * There is nothing at "end". If we end up there
3086 * we need to add something to before end.
3091 caddr
= t
->loc
[pos
].addr
;
3092 if (track
->addr
== caddr
) {
3098 if (age
< l
->min_time
)
3100 if (age
> l
->max_time
)
3103 if (track
->pid
< l
->min_pid
)
3104 l
->min_pid
= track
->pid
;
3105 if (track
->pid
> l
->max_pid
)
3106 l
->max_pid
= track
->pid
;
3108 cpu_set(track
->cpu
, l
->cpus
);
3110 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3114 if (track
->addr
< caddr
)
3121 * Not found. Insert new tracking element.
3123 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
3129 (t
->count
- pos
) * sizeof(struct location
));
3132 l
->addr
= track
->addr
;
3136 l
->min_pid
= track
->pid
;
3137 l
->max_pid
= track
->pid
;
3138 cpus_clear(l
->cpus
);
3139 cpu_set(track
->cpu
, l
->cpus
);
3140 nodes_clear(l
->nodes
);
3141 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3145 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
3146 struct page
*page
, enum track_item alloc
)
3148 void *addr
= page_address(page
);
3149 DECLARE_BITMAP(map
, s
->objects
);
3152 bitmap_zero(map
, s
->objects
);
3153 for_each_free_object(p
, s
, page
->freelist
)
3154 set_bit(slab_index(p
, s
, addr
), map
);
3156 for_each_object(p
, s
, addr
)
3157 if (!test_bit(slab_index(p
, s
, addr
), map
))
3158 add_location(t
, s
, get_track(s
, p
, alloc
));
3161 static int list_locations(struct kmem_cache
*s
, char *buf
,
3162 enum track_item alloc
)
3166 struct loc_track t
= { 0, 0, NULL
};
3169 if (!alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
3171 return sprintf(buf
, "Out of memory\n");
3173 /* Push back cpu slabs */
3176 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3177 struct kmem_cache_node
*n
= get_node(s
, node
);
3178 unsigned long flags
;
3181 if (!atomic_long_read(&n
->nr_slabs
))
3184 spin_lock_irqsave(&n
->list_lock
, flags
);
3185 list_for_each_entry(page
, &n
->partial
, lru
)
3186 process_slab(&t
, s
, page
, alloc
);
3187 list_for_each_entry(page
, &n
->full
, lru
)
3188 process_slab(&t
, s
, page
, alloc
);
3189 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3192 for (i
= 0; i
< t
.count
; i
++) {
3193 struct location
*l
= &t
.loc
[i
];
3195 if (n
> PAGE_SIZE
- 100)
3197 n
+= sprintf(buf
+ n
, "%7ld ", l
->count
);
3200 n
+= sprint_symbol(buf
+ n
, (unsigned long)l
->addr
);
3202 n
+= sprintf(buf
+ n
, "<not-available>");
3204 if (l
->sum_time
!= l
->min_time
) {
3205 unsigned long remainder
;
3207 n
+= sprintf(buf
+ n
, " age=%ld/%ld/%ld",
3209 div_long_long_rem(l
->sum_time
, l
->count
, &remainder
),
3212 n
+= sprintf(buf
+ n
, " age=%ld",
3215 if (l
->min_pid
!= l
->max_pid
)
3216 n
+= sprintf(buf
+ n
, " pid=%ld-%ld",
3217 l
->min_pid
, l
->max_pid
);
3219 n
+= sprintf(buf
+ n
, " pid=%ld",
3222 if (num_online_cpus() > 1 && !cpus_empty(l
->cpus
) &&
3223 n
< PAGE_SIZE
- 60) {
3224 n
+= sprintf(buf
+ n
, " cpus=");
3225 n
+= cpulist_scnprintf(buf
+ n
, PAGE_SIZE
- n
- 50,
3229 if (num_online_nodes() > 1 && !nodes_empty(l
->nodes
) &&
3230 n
< PAGE_SIZE
- 60) {
3231 n
+= sprintf(buf
+ n
, " nodes=");
3232 n
+= nodelist_scnprintf(buf
+ n
, PAGE_SIZE
- n
- 50,
3236 n
+= sprintf(buf
+ n
, "\n");
3241 n
+= sprintf(buf
, "No data\n");
3245 static unsigned long count_partial(struct kmem_cache_node
*n
)
3247 unsigned long flags
;
3248 unsigned long x
= 0;
3251 spin_lock_irqsave(&n
->list_lock
, flags
);
3252 list_for_each_entry(page
, &n
->partial
, lru
)
3254 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3258 enum slab_stat_type
{
3265 #define SO_FULL (1 << SL_FULL)
3266 #define SO_PARTIAL (1 << SL_PARTIAL)
3267 #define SO_CPU (1 << SL_CPU)
3268 #define SO_OBJECTS (1 << SL_OBJECTS)
3270 static unsigned long slab_objects(struct kmem_cache
*s
,
3271 char *buf
, unsigned long flags
)
3273 unsigned long total
= 0;
3277 unsigned long *nodes
;
3278 unsigned long *per_cpu
;
3280 nodes
= kzalloc(2 * sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
3281 per_cpu
= nodes
+ nr_node_ids
;
3283 for_each_possible_cpu(cpu
) {
3285 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3292 if (flags
& SO_CPU
) {
3295 if (flags
& SO_OBJECTS
)
3300 nodes
[c
->node
] += x
;
3306 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3307 struct kmem_cache_node
*n
= get_node(s
, node
);
3309 if (flags
& SO_PARTIAL
) {
3310 if (flags
& SO_OBJECTS
)
3311 x
= count_partial(n
);
3318 if (flags
& SO_FULL
) {
3319 int full_slabs
= atomic_long_read(&n
->nr_slabs
)
3323 if (flags
& SO_OBJECTS
)
3324 x
= full_slabs
* s
->objects
;
3332 x
= sprintf(buf
, "%lu", total
);
3334 for_each_node_state(node
, N_NORMAL_MEMORY
)
3336 x
+= sprintf(buf
+ x
, " N%d=%lu",
3340 return x
+ sprintf(buf
+ x
, "\n");
3343 static int any_slab_objects(struct kmem_cache
*s
)
3348 for_each_possible_cpu(cpu
) {
3349 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3355 for_each_online_node(node
) {
3356 struct kmem_cache_node
*n
= get_node(s
, node
);
3361 if (n
->nr_partial
|| atomic_long_read(&n
->nr_slabs
))
3367 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3368 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3370 struct slab_attribute
{
3371 struct attribute attr
;
3372 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
3373 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
3376 #define SLAB_ATTR_RO(_name) \
3377 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3379 #define SLAB_ATTR(_name) \
3380 static struct slab_attribute _name##_attr = \
3381 __ATTR(_name, 0644, _name##_show, _name##_store)
3383 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
3385 return sprintf(buf
, "%d\n", s
->size
);
3387 SLAB_ATTR_RO(slab_size
);
3389 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
3391 return sprintf(buf
, "%d\n", s
->align
);
3393 SLAB_ATTR_RO(align
);
3395 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
3397 return sprintf(buf
, "%d\n", s
->objsize
);
3399 SLAB_ATTR_RO(object_size
);
3401 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
3403 return sprintf(buf
, "%d\n", s
->objects
);
3405 SLAB_ATTR_RO(objs_per_slab
);
3407 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
3409 return sprintf(buf
, "%d\n", s
->order
);
3411 SLAB_ATTR_RO(order
);
3413 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
3416 int n
= sprint_symbol(buf
, (unsigned long)s
->ctor
);
3418 return n
+ sprintf(buf
+ n
, "\n");
3424 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
3426 return sprintf(buf
, "%d\n", s
->refcount
- 1);
3428 SLAB_ATTR_RO(aliases
);
3430 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
3432 return slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
);
3434 SLAB_ATTR_RO(slabs
);
3436 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
3438 return slab_objects(s
, buf
, SO_PARTIAL
);
3440 SLAB_ATTR_RO(partial
);
3442 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
3444 return slab_objects(s
, buf
, SO_CPU
);
3446 SLAB_ATTR_RO(cpu_slabs
);
3448 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
3450 return slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
|SO_OBJECTS
);
3452 SLAB_ATTR_RO(objects
);
3454 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
3456 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
3459 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
3460 const char *buf
, size_t length
)
3462 s
->flags
&= ~SLAB_DEBUG_FREE
;
3464 s
->flags
|= SLAB_DEBUG_FREE
;
3467 SLAB_ATTR(sanity_checks
);
3469 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
3471 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
3474 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
3477 s
->flags
&= ~SLAB_TRACE
;
3479 s
->flags
|= SLAB_TRACE
;
3484 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
3486 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
3489 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
3490 const char *buf
, size_t length
)
3492 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
3494 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
3497 SLAB_ATTR(reclaim_account
);
3499 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
3501 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
3503 SLAB_ATTR_RO(hwcache_align
);
3505 #ifdef CONFIG_ZONE_DMA
3506 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
3508 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
3510 SLAB_ATTR_RO(cache_dma
);
3513 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
3515 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
3517 SLAB_ATTR_RO(destroy_by_rcu
);
3519 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
3521 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
3524 static ssize_t
red_zone_store(struct kmem_cache
*s
,
3525 const char *buf
, size_t length
)
3527 if (any_slab_objects(s
))
3530 s
->flags
&= ~SLAB_RED_ZONE
;
3532 s
->flags
|= SLAB_RED_ZONE
;
3536 SLAB_ATTR(red_zone
);
3538 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
3540 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
3543 static ssize_t
poison_store(struct kmem_cache
*s
,
3544 const char *buf
, size_t length
)
3546 if (any_slab_objects(s
))
3549 s
->flags
&= ~SLAB_POISON
;
3551 s
->flags
|= SLAB_POISON
;
3557 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
3559 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
3562 static ssize_t
store_user_store(struct kmem_cache
*s
,
3563 const char *buf
, size_t length
)
3565 if (any_slab_objects(s
))
3568 s
->flags
&= ~SLAB_STORE_USER
;
3570 s
->flags
|= SLAB_STORE_USER
;
3574 SLAB_ATTR(store_user
);
3576 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
3581 static ssize_t
validate_store(struct kmem_cache
*s
,
3582 const char *buf
, size_t length
)
3586 if (buf
[0] == '1') {
3587 ret
= validate_slab_cache(s
);
3593 SLAB_ATTR(validate
);
3595 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
3600 static ssize_t
shrink_store(struct kmem_cache
*s
,
3601 const char *buf
, size_t length
)
3603 if (buf
[0] == '1') {
3604 int rc
= kmem_cache_shrink(s
);
3614 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
3616 if (!(s
->flags
& SLAB_STORE_USER
))
3618 return list_locations(s
, buf
, TRACK_ALLOC
);
3620 SLAB_ATTR_RO(alloc_calls
);
3622 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
3624 if (!(s
->flags
& SLAB_STORE_USER
))
3626 return list_locations(s
, buf
, TRACK_FREE
);
3628 SLAB_ATTR_RO(free_calls
);
3631 static ssize_t
defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
3633 return sprintf(buf
, "%d\n", s
->defrag_ratio
/ 10);
3636 static ssize_t
defrag_ratio_store(struct kmem_cache
*s
,
3637 const char *buf
, size_t length
)
3639 int n
= simple_strtoul(buf
, NULL
, 10);
3642 s
->defrag_ratio
= n
* 10;
3645 SLAB_ATTR(defrag_ratio
);
3648 static struct attribute
* slab_attrs
[] = {
3649 &slab_size_attr
.attr
,
3650 &object_size_attr
.attr
,
3651 &objs_per_slab_attr
.attr
,
3656 &cpu_slabs_attr
.attr
,
3660 &sanity_checks_attr
.attr
,
3662 &hwcache_align_attr
.attr
,
3663 &reclaim_account_attr
.attr
,
3664 &destroy_by_rcu_attr
.attr
,
3665 &red_zone_attr
.attr
,
3667 &store_user_attr
.attr
,
3668 &validate_attr
.attr
,
3670 &alloc_calls_attr
.attr
,
3671 &free_calls_attr
.attr
,
3672 #ifdef CONFIG_ZONE_DMA
3673 &cache_dma_attr
.attr
,
3676 &defrag_ratio_attr
.attr
,
3681 static struct attribute_group slab_attr_group
= {
3682 .attrs
= slab_attrs
,
3685 static ssize_t
slab_attr_show(struct kobject
*kobj
,
3686 struct attribute
*attr
,
3689 struct slab_attribute
*attribute
;
3690 struct kmem_cache
*s
;
3693 attribute
= to_slab_attr(attr
);
3696 if (!attribute
->show
)
3699 err
= attribute
->show(s
, buf
);
3704 static ssize_t
slab_attr_store(struct kobject
*kobj
,
3705 struct attribute
*attr
,
3706 const char *buf
, size_t len
)
3708 struct slab_attribute
*attribute
;
3709 struct kmem_cache
*s
;
3712 attribute
= to_slab_attr(attr
);
3715 if (!attribute
->store
)
3718 err
= attribute
->store(s
, buf
, len
);
3723 static struct sysfs_ops slab_sysfs_ops
= {
3724 .show
= slab_attr_show
,
3725 .store
= slab_attr_store
,
3728 static struct kobj_type slab_ktype
= {
3729 .sysfs_ops
= &slab_sysfs_ops
,
3732 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
3734 struct kobj_type
*ktype
= get_ktype(kobj
);
3736 if (ktype
== &slab_ktype
)
3741 static struct kset_uevent_ops slab_uevent_ops
= {
3742 .filter
= uevent_filter
,
3745 static decl_subsys(slab
, &slab_ktype
, &slab_uevent_ops
);
3747 #define ID_STR_LENGTH 64
3749 /* Create a unique string id for a slab cache:
3751 * :[flags-]size:[memory address of kmemcache]
3753 static char *create_unique_id(struct kmem_cache
*s
)
3755 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
3762 * First flags affecting slabcache operations. We will only
3763 * get here for aliasable slabs so we do not need to support
3764 * too many flags. The flags here must cover all flags that
3765 * are matched during merging to guarantee that the id is
3768 if (s
->flags
& SLAB_CACHE_DMA
)
3770 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3772 if (s
->flags
& SLAB_DEBUG_FREE
)
3776 p
+= sprintf(p
, "%07d", s
->size
);
3777 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
3781 static int sysfs_slab_add(struct kmem_cache
*s
)
3787 if (slab_state
< SYSFS
)
3788 /* Defer until later */
3791 unmergeable
= slab_unmergeable(s
);
3794 * Slabcache can never be merged so we can use the name proper.
3795 * This is typically the case for debug situations. In that
3796 * case we can catch duplicate names easily.
3798 sysfs_remove_link(&slab_subsys
.kobj
, s
->name
);
3802 * Create a unique name for the slab as a target
3805 name
= create_unique_id(s
);
3808 kobj_set_kset_s(s
, slab_subsys
);
3809 kobject_set_name(&s
->kobj
, name
);
3810 kobject_init(&s
->kobj
);
3811 err
= kobject_add(&s
->kobj
);
3815 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
3818 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
3820 /* Setup first alias */
3821 sysfs_slab_alias(s
, s
->name
);
3827 static void sysfs_slab_remove(struct kmem_cache
*s
)
3829 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
3830 kobject_del(&s
->kobj
);
3834 * Need to buffer aliases during bootup until sysfs becomes
3835 * available lest we loose that information.
3837 struct saved_alias
{
3838 struct kmem_cache
*s
;
3840 struct saved_alias
*next
;
3843 static struct saved_alias
*alias_list
;
3845 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
3847 struct saved_alias
*al
;
3849 if (slab_state
== SYSFS
) {
3851 * If we have a leftover link then remove it.
3853 sysfs_remove_link(&slab_subsys
.kobj
, name
);
3854 return sysfs_create_link(&slab_subsys
.kobj
,
3858 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
3864 al
->next
= alias_list
;
3869 static int __init
slab_sysfs_init(void)
3871 struct kmem_cache
*s
;
3874 err
= subsystem_register(&slab_subsys
);
3876 printk(KERN_ERR
"Cannot register slab subsystem.\n");
3882 list_for_each_entry(s
, &slab_caches
, list
) {
3883 err
= sysfs_slab_add(s
);
3885 printk(KERN_ERR
"SLUB: Unable to add boot slab %s"
3886 " to sysfs\n", s
->name
);
3889 while (alias_list
) {
3890 struct saved_alias
*al
= alias_list
;
3892 alias_list
= alias_list
->next
;
3893 err
= sysfs_slab_alias(al
->s
, al
->name
);
3895 printk(KERN_ERR
"SLUB: Unable to add boot slab alias"
3896 " %s to sysfs\n", s
->name
);
3904 __initcall(slab_sysfs_init
);