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>
23 #include <linux/memory.h>
30 * The slab_lock protects operations on the object of a particular
31 * slab and its metadata in the page struct. If the slab lock
32 * has been taken then no allocations nor frees can be performed
33 * on the objects in the slab nor can the slab be added or removed
34 * from the partial or full lists since this would mean modifying
35 * the page_struct of the slab.
37 * The list_lock protects the partial and full list on each node and
38 * the partial slab counter. If taken then no new slabs may be added or
39 * removed from the lists nor make the number of partial slabs be modified.
40 * (Note that the total number of slabs is an atomic value that may be
41 * modified without taking the list lock).
43 * The list_lock is a centralized lock and thus we avoid taking it as
44 * much as possible. As long as SLUB does not have to handle partial
45 * slabs, operations can continue without any centralized lock. F.e.
46 * allocating a long series of objects that fill up slabs does not require
49 * The lock order is sometimes inverted when we are trying to get a slab
50 * off a list. We take the list_lock and then look for a page on the list
51 * to use. While we do that objects in the slabs may be freed. We can
52 * only operate on the slab if we have also taken the slab_lock. So we use
53 * a slab_trylock() on the slab. If trylock was successful then no frees
54 * can occur anymore and we can use the slab for allocations etc. If the
55 * slab_trylock() does not succeed then frees are in progress in the slab and
56 * we must stay away from it for a while since we may cause a bouncing
57 * cacheline if we try to acquire the lock. So go onto the next slab.
58 * If all pages are busy then we may allocate a new slab instead of reusing
59 * a partial slab. A new slab has noone operating on it and thus there is
60 * no danger of cacheline contention.
62 * Interrupts are disabled during allocation and deallocation in order to
63 * make the slab allocator safe to use in the context of an irq. In addition
64 * interrupts are disabled to ensure that the processor does not change
65 * while handling per_cpu slabs, due to kernel preemption.
67 * SLUB assigns one slab for allocation to each processor.
68 * Allocations only occur from these slabs called cpu slabs.
70 * Slabs with free elements are kept on a partial list and during regular
71 * operations no list for full slabs is used. If an object in a full slab is
72 * freed then the slab will show up again on the partial lists.
73 * We track full slabs for debugging purposes though because otherwise we
74 * cannot scan all objects.
76 * Slabs are freed when they become empty. Teardown and setup is
77 * minimal so we rely on the page allocators per cpu caches for
78 * fast frees and allocs.
80 * Overloading of page flags that are otherwise used for LRU management.
82 * PageActive The slab is frozen and exempt from list processing.
83 * This means that the slab is dedicated to a purpose
84 * such as satisfying allocations for a specific
85 * processor. Objects may be freed in the slab while
86 * it is frozen but slab_free will then skip the usual
87 * list operations. It is up to the processor holding
88 * the slab to integrate the slab into the slab lists
89 * when the slab is no longer needed.
91 * One use of this flag is to mark slabs that are
92 * used for allocations. Then such a slab becomes a cpu
93 * slab. The cpu slab may be equipped with an additional
94 * freelist that allows lockless access to
95 * free objects in addition to the regular freelist
96 * that requires the slab lock.
98 * PageError Slab requires special handling due to debug
99 * options set. This moves slab handling out of
100 * the fast path and disables lockless freelists.
103 #define FROZEN (1 << PG_active)
105 #ifdef CONFIG_SLUB_DEBUG
106 #define SLABDEBUG (1 << PG_error)
111 static inline int SlabFrozen(struct page
*page
)
113 return page
->flags
& FROZEN
;
116 static inline void SetSlabFrozen(struct page
*page
)
118 page
->flags
|= FROZEN
;
121 static inline void ClearSlabFrozen(struct page
*page
)
123 page
->flags
&= ~FROZEN
;
126 static inline int SlabDebug(struct page
*page
)
128 return page
->flags
& SLABDEBUG
;
131 static inline void SetSlabDebug(struct page
*page
)
133 page
->flags
|= SLABDEBUG
;
136 static inline void ClearSlabDebug(struct page
*page
)
138 page
->flags
&= ~SLABDEBUG
;
142 * Issues still to be resolved:
144 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
146 * - Variable sizing of the per node arrays
149 /* Enable to test recovery from slab corruption on boot */
150 #undef SLUB_RESILIENCY_TEST
155 * Small page size. Make sure that we do not fragment memory
157 #define DEFAULT_MAX_ORDER 1
158 #define DEFAULT_MIN_OBJECTS 4
163 * Large page machines are customarily able to handle larger
166 #define DEFAULT_MAX_ORDER 2
167 #define DEFAULT_MIN_OBJECTS 8
172 * Mininum number of partial slabs. These will be left on the partial
173 * lists even if they are empty. kmem_cache_shrink may reclaim them.
175 #define MIN_PARTIAL 5
178 * Maximum number of desirable partial slabs.
179 * The existence of more partial slabs makes kmem_cache_shrink
180 * sort the partial list by the number of objects in the.
182 #define MAX_PARTIAL 10
184 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
185 SLAB_POISON | SLAB_STORE_USER)
188 * Set of flags that will prevent slab merging
190 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
191 SLAB_TRACE | SLAB_DESTROY_BY_RCU)
193 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
196 #ifndef ARCH_KMALLOC_MINALIGN
197 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
200 #ifndef ARCH_SLAB_MINALIGN
201 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
204 /* Internal SLUB flags */
205 #define __OBJECT_POISON 0x80000000 /* Poison object */
206 #define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */
207 #define __KMALLOC_CACHE 0x20000000 /* objects freed using kfree */
208 #define __PAGE_ALLOC_FALLBACK 0x10000000 /* Allow fallback to page alloc */
210 /* Not all arches define cache_line_size */
211 #ifndef cache_line_size
212 #define cache_line_size() L1_CACHE_BYTES
215 static int kmem_size
= sizeof(struct kmem_cache
);
218 static struct notifier_block slab_notifier
;
222 DOWN
, /* No slab functionality available */
223 PARTIAL
, /* kmem_cache_open() works but kmalloc does not */
224 UP
, /* Everything works but does not show up in sysfs */
228 /* A list of all slab caches on the system */
229 static DECLARE_RWSEM(slub_lock
);
230 static LIST_HEAD(slab_caches
);
233 * Tracking user of a slab.
236 void *addr
; /* Called from address */
237 int cpu
; /* Was running on cpu */
238 int pid
; /* Pid context */
239 unsigned long when
; /* When did the operation occur */
242 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
244 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
245 static int sysfs_slab_add(struct kmem_cache
*);
246 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
247 static void sysfs_slab_remove(struct kmem_cache
*);
250 static inline int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
251 static inline int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
)
253 static inline void sysfs_slab_remove(struct kmem_cache
*s
)
260 static inline void stat(struct kmem_cache_cpu
*c
, enum stat_item si
)
262 #ifdef CONFIG_SLUB_STATS
267 /********************************************************************
268 * Core slab cache functions
269 *******************************************************************/
271 int slab_is_available(void)
273 return slab_state
>= UP
;
276 static inline struct kmem_cache_node
*get_node(struct kmem_cache
*s
, int node
)
279 return s
->node
[node
];
281 return &s
->local_node
;
285 static inline struct kmem_cache_cpu
*get_cpu_slab(struct kmem_cache
*s
, int cpu
)
288 return s
->cpu_slab
[cpu
];
294 static inline int check_valid_pointer(struct kmem_cache
*s
,
295 struct page
*page
, const void *object
)
302 base
= page_address(page
);
303 if (object
< base
|| object
>= base
+ s
->objects
* s
->size
||
304 (object
- base
) % s
->size
) {
312 * Slow version of get and set free pointer.
314 * This version requires touching the cache lines of kmem_cache which
315 * we avoid to do in the fast alloc free paths. There we obtain the offset
316 * from the page struct.
318 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
320 return *(void **)(object
+ s
->offset
);
323 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
325 *(void **)(object
+ s
->offset
) = fp
;
328 /* Loop over all objects in a slab */
329 #define for_each_object(__p, __s, __addr) \
330 for (__p = (__addr); __p < (__addr) + (__s)->objects * (__s)->size;\
334 #define for_each_free_object(__p, __s, __free) \
335 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
337 /* Determine object index from a given position */
338 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
340 return (p
- addr
) / s
->size
;
343 #ifdef CONFIG_SLUB_DEBUG
347 #ifdef CONFIG_SLUB_DEBUG_ON
348 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
350 static int slub_debug
;
353 static char *slub_debug_slabs
;
358 static void print_section(char *text
, u8
*addr
, unsigned int length
)
366 for (i
= 0; i
< length
; i
++) {
368 printk(KERN_ERR
"%8s 0x%p: ", text
, addr
+ i
);
371 printk(KERN_CONT
" %02x", addr
[i
]);
373 ascii
[offset
] = isgraph(addr
[i
]) ? addr
[i
] : '.';
375 printk(KERN_CONT
" %s\n", ascii
);
382 printk(KERN_CONT
" ");
386 printk(KERN_CONT
" %s\n", ascii
);
390 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
391 enum track_item alloc
)
396 p
= object
+ s
->offset
+ sizeof(void *);
398 p
= object
+ s
->inuse
;
403 static void set_track(struct kmem_cache
*s
, void *object
,
404 enum track_item alloc
, void *addr
)
409 p
= object
+ s
->offset
+ sizeof(void *);
411 p
= object
+ s
->inuse
;
416 p
->cpu
= smp_processor_id();
417 p
->pid
= current
? current
->pid
: -1;
420 memset(p
, 0, sizeof(struct track
));
423 static void init_tracking(struct kmem_cache
*s
, void *object
)
425 if (!(s
->flags
& SLAB_STORE_USER
))
428 set_track(s
, object
, TRACK_FREE
, NULL
);
429 set_track(s
, object
, TRACK_ALLOC
, NULL
);
432 static void print_track(const char *s
, struct track
*t
)
437 printk(KERN_ERR
"INFO: %s in ", s
);
438 __print_symbol("%s", (unsigned long)t
->addr
);
439 printk(" age=%lu cpu=%u pid=%d\n", jiffies
- t
->when
, t
->cpu
, t
->pid
);
442 static void print_tracking(struct kmem_cache
*s
, void *object
)
444 if (!(s
->flags
& SLAB_STORE_USER
))
447 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
448 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
451 static void print_page_info(struct page
*page
)
453 printk(KERN_ERR
"INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n",
454 page
, page
->inuse
, page
->freelist
, page
->flags
);
458 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
464 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
466 printk(KERN_ERR
"========================================"
467 "=====================================\n");
468 printk(KERN_ERR
"BUG %s: %s\n", s
->name
, buf
);
469 printk(KERN_ERR
"----------------------------------------"
470 "-------------------------------------\n\n");
473 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
479 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
481 printk(KERN_ERR
"FIX %s: %s\n", s
->name
, buf
);
484 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
486 unsigned int off
; /* Offset of last byte */
487 u8
*addr
= page_address(page
);
489 print_tracking(s
, p
);
491 print_page_info(page
);
493 printk(KERN_ERR
"INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
494 p
, p
- addr
, get_freepointer(s
, p
));
497 print_section("Bytes b4", p
- 16, 16);
499 print_section("Object", p
, min(s
->objsize
, 128));
501 if (s
->flags
& SLAB_RED_ZONE
)
502 print_section("Redzone", p
+ s
->objsize
,
503 s
->inuse
- s
->objsize
);
506 off
= s
->offset
+ sizeof(void *);
510 if (s
->flags
& SLAB_STORE_USER
)
511 off
+= 2 * sizeof(struct track
);
514 /* Beginning of the filler is the free pointer */
515 print_section("Padding", p
+ off
, s
->size
- off
);
520 static void object_err(struct kmem_cache
*s
, struct page
*page
,
521 u8
*object
, char *reason
)
524 print_trailer(s
, page
, object
);
527 static void slab_err(struct kmem_cache
*s
, struct page
*page
, char *fmt
, ...)
533 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
536 print_page_info(page
);
540 static void init_object(struct kmem_cache
*s
, void *object
, int active
)
544 if (s
->flags
& __OBJECT_POISON
) {
545 memset(p
, POISON_FREE
, s
->objsize
- 1);
546 p
[s
->objsize
- 1] = POISON_END
;
549 if (s
->flags
& SLAB_RED_ZONE
)
550 memset(p
+ s
->objsize
,
551 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
,
552 s
->inuse
- s
->objsize
);
555 static u8
*check_bytes(u8
*start
, unsigned int value
, unsigned int bytes
)
558 if (*start
!= (u8
)value
)
566 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
567 void *from
, void *to
)
569 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
570 memset(from
, data
, to
- from
);
573 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
574 u8
*object
, char *what
,
575 u8
*start
, unsigned int value
, unsigned int bytes
)
580 fault
= check_bytes(start
, value
, bytes
);
585 while (end
> fault
&& end
[-1] == value
)
588 slab_bug(s
, "%s overwritten", what
);
589 printk(KERN_ERR
"INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
590 fault
, end
- 1, fault
[0], value
);
591 print_trailer(s
, page
, object
);
593 restore_bytes(s
, what
, value
, fault
, end
);
601 * Bytes of the object to be managed.
602 * If the freepointer may overlay the object then the free
603 * pointer is the first word of the object.
605 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
608 * object + s->objsize
609 * Padding to reach word boundary. This is also used for Redzoning.
610 * Padding is extended by another word if Redzoning is enabled and
613 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
614 * 0xcc (RED_ACTIVE) for objects in use.
617 * Meta data starts here.
619 * A. Free pointer (if we cannot overwrite object on free)
620 * B. Tracking data for SLAB_STORE_USER
621 * C. Padding to reach required alignment boundary or at mininum
622 * one word if debuggin is on to be able to detect writes
623 * before the word boundary.
625 * Padding is done using 0x5a (POISON_INUSE)
628 * Nothing is used beyond s->size.
630 * If slabcaches are merged then the objsize and inuse boundaries are mostly
631 * ignored. And therefore no slab options that rely on these boundaries
632 * may be used with merged slabcaches.
635 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
637 unsigned long off
= s
->inuse
; /* The end of info */
640 /* Freepointer is placed after the object. */
641 off
+= sizeof(void *);
643 if (s
->flags
& SLAB_STORE_USER
)
644 /* We also have user information there */
645 off
+= 2 * sizeof(struct track
);
650 return check_bytes_and_report(s
, page
, p
, "Object padding",
651 p
+ off
, POISON_INUSE
, s
->size
- off
);
654 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
662 if (!(s
->flags
& SLAB_POISON
))
665 start
= page_address(page
);
666 end
= start
+ (PAGE_SIZE
<< s
->order
);
667 length
= s
->objects
* s
->size
;
668 remainder
= end
- (start
+ length
);
672 fault
= check_bytes(start
+ length
, POISON_INUSE
, remainder
);
675 while (end
> fault
&& end
[-1] == POISON_INUSE
)
678 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
679 print_section("Padding", start
, length
);
681 restore_bytes(s
, "slab padding", POISON_INUSE
, start
, end
);
685 static int check_object(struct kmem_cache
*s
, struct page
*page
,
686 void *object
, int active
)
689 u8
*endobject
= object
+ s
->objsize
;
691 if (s
->flags
& SLAB_RED_ZONE
) {
693 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
;
695 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
696 endobject
, red
, s
->inuse
- s
->objsize
))
699 if ((s
->flags
& SLAB_POISON
) && s
->objsize
< s
->inuse
) {
700 check_bytes_and_report(s
, page
, p
, "Alignment padding",
701 endobject
, POISON_INUSE
, s
->inuse
- s
->objsize
);
705 if (s
->flags
& SLAB_POISON
) {
706 if (!active
&& (s
->flags
& __OBJECT_POISON
) &&
707 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
708 POISON_FREE
, s
->objsize
- 1) ||
709 !check_bytes_and_report(s
, page
, p
, "Poison",
710 p
+ s
->objsize
- 1, POISON_END
, 1)))
713 * check_pad_bytes cleans up on its own.
715 check_pad_bytes(s
, page
, p
);
718 if (!s
->offset
&& active
)
720 * Object and freepointer overlap. Cannot check
721 * freepointer while object is allocated.
725 /* Check free pointer validity */
726 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
727 object_err(s
, page
, p
, "Freepointer corrupt");
729 * No choice but to zap it and thus loose the remainder
730 * of the free objects in this slab. May cause
731 * another error because the object count is now wrong.
733 set_freepointer(s
, p
, NULL
);
739 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
741 VM_BUG_ON(!irqs_disabled());
743 if (!PageSlab(page
)) {
744 slab_err(s
, page
, "Not a valid slab page");
747 if (page
->inuse
> s
->objects
) {
748 slab_err(s
, page
, "inuse %u > max %u",
749 s
->name
, page
->inuse
, s
->objects
);
752 /* Slab_pad_check fixes things up after itself */
753 slab_pad_check(s
, page
);
758 * Determine if a certain object on a page is on the freelist. Must hold the
759 * slab lock to guarantee that the chains are in a consistent state.
761 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
764 void *fp
= page
->freelist
;
767 while (fp
&& nr
<= s
->objects
) {
770 if (!check_valid_pointer(s
, page
, fp
)) {
772 object_err(s
, page
, object
,
773 "Freechain corrupt");
774 set_freepointer(s
, object
, NULL
);
777 slab_err(s
, page
, "Freepointer corrupt");
778 page
->freelist
= NULL
;
779 page
->inuse
= s
->objects
;
780 slab_fix(s
, "Freelist cleared");
786 fp
= get_freepointer(s
, object
);
790 if (page
->inuse
!= s
->objects
- nr
) {
791 slab_err(s
, page
, "Wrong object count. Counter is %d but "
792 "counted were %d", page
->inuse
, s
->objects
- nr
);
793 page
->inuse
= s
->objects
- nr
;
794 slab_fix(s
, "Object count adjusted.");
796 return search
== NULL
;
799 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
, int alloc
)
801 if (s
->flags
& SLAB_TRACE
) {
802 printk(KERN_INFO
"TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
804 alloc
? "alloc" : "free",
809 print_section("Object", (void *)object
, s
->objsize
);
816 * Tracking of fully allocated slabs for debugging purposes.
818 static void add_full(struct kmem_cache_node
*n
, struct page
*page
)
820 spin_lock(&n
->list_lock
);
821 list_add(&page
->lru
, &n
->full
);
822 spin_unlock(&n
->list_lock
);
825 static void remove_full(struct kmem_cache
*s
, struct page
*page
)
827 struct kmem_cache_node
*n
;
829 if (!(s
->flags
& SLAB_STORE_USER
))
832 n
= get_node(s
, page_to_nid(page
));
834 spin_lock(&n
->list_lock
);
835 list_del(&page
->lru
);
836 spin_unlock(&n
->list_lock
);
839 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
842 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
845 init_object(s
, object
, 0);
846 init_tracking(s
, object
);
849 static int alloc_debug_processing(struct kmem_cache
*s
, struct page
*page
,
850 void *object
, void *addr
)
852 if (!check_slab(s
, page
))
855 if (object
&& !on_freelist(s
, page
, object
)) {
856 object_err(s
, page
, object
, "Object already allocated");
860 if (!check_valid_pointer(s
, page
, object
)) {
861 object_err(s
, page
, object
, "Freelist Pointer check fails");
865 if (object
&& !check_object(s
, page
, object
, 0))
868 /* Success perform special debug activities for allocs */
869 if (s
->flags
& SLAB_STORE_USER
)
870 set_track(s
, object
, TRACK_ALLOC
, addr
);
871 trace(s
, page
, object
, 1);
872 init_object(s
, object
, 1);
876 if (PageSlab(page
)) {
878 * If this is a slab page then lets do the best we can
879 * to avoid issues in the future. Marking all objects
880 * as used avoids touching the remaining objects.
882 slab_fix(s
, "Marking all objects used");
883 page
->inuse
= s
->objects
;
884 page
->freelist
= NULL
;
889 static int free_debug_processing(struct kmem_cache
*s
, struct page
*page
,
890 void *object
, void *addr
)
892 if (!check_slab(s
, page
))
895 if (!check_valid_pointer(s
, page
, object
)) {
896 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
900 if (on_freelist(s
, page
, object
)) {
901 object_err(s
, page
, object
, "Object already free");
905 if (!check_object(s
, page
, object
, 1))
908 if (unlikely(s
!= page
->slab
)) {
909 if (!PageSlab(page
)) {
910 slab_err(s
, page
, "Attempt to free object(0x%p) "
911 "outside of slab", object
);
912 } else if (!page
->slab
) {
914 "SLUB <none>: no slab for object 0x%p.\n",
918 object_err(s
, page
, object
,
919 "page slab pointer corrupt.");
923 /* Special debug activities for freeing objects */
924 if (!SlabFrozen(page
) && !page
->freelist
)
925 remove_full(s
, page
);
926 if (s
->flags
& SLAB_STORE_USER
)
927 set_track(s
, object
, TRACK_FREE
, addr
);
928 trace(s
, page
, object
, 0);
929 init_object(s
, object
, 0);
933 slab_fix(s
, "Object at 0x%p not freed", object
);
937 static int __init
setup_slub_debug(char *str
)
939 slub_debug
= DEBUG_DEFAULT_FLAGS
;
940 if (*str
++ != '=' || !*str
)
942 * No options specified. Switch on full debugging.
948 * No options but restriction on slabs. This means full
949 * debugging for slabs matching a pattern.
956 * Switch off all debugging measures.
961 * Determine which debug features should be switched on
963 for (; *str
&& *str
!= ','; str
++) {
964 switch (tolower(*str
)) {
966 slub_debug
|= SLAB_DEBUG_FREE
;
969 slub_debug
|= SLAB_RED_ZONE
;
972 slub_debug
|= SLAB_POISON
;
975 slub_debug
|= SLAB_STORE_USER
;
978 slub_debug
|= SLAB_TRACE
;
981 printk(KERN_ERR
"slub_debug option '%c' "
982 "unknown. skipped\n", *str
);
988 slub_debug_slabs
= str
+ 1;
993 __setup("slub_debug", setup_slub_debug
);
995 static unsigned long kmem_cache_flags(unsigned long objsize
,
996 unsigned long flags
, const char *name
,
997 void (*ctor
)(struct kmem_cache
*, void *))
1000 * The page->offset field is only 16 bit wide. This is an offset
1001 * in units of words from the beginning of an object. If the slab
1002 * size is bigger then we cannot move the free pointer behind the
1005 * On 32 bit platforms the limit is 256k. On 64bit platforms
1006 * the limit is 512k.
1008 * Debugging or ctor may create a need to move the free
1009 * pointer. Fail if this happens.
1011 if (objsize
>= 65535 * sizeof(void *)) {
1012 BUG_ON(flags
& (SLAB_RED_ZONE
| SLAB_POISON
|
1013 SLAB_STORE_USER
| SLAB_DESTROY_BY_RCU
));
1017 * Enable debugging if selected on the kernel commandline.
1019 if (slub_debug
&& (!slub_debug_slabs
||
1020 strncmp(slub_debug_slabs
, name
,
1021 strlen(slub_debug_slabs
)) == 0))
1022 flags
|= slub_debug
;
1028 static inline void setup_object_debug(struct kmem_cache
*s
,
1029 struct page
*page
, void *object
) {}
1031 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1032 struct page
*page
, void *object
, void *addr
) { return 0; }
1034 static inline int free_debug_processing(struct kmem_cache
*s
,
1035 struct page
*page
, void *object
, void *addr
) { return 0; }
1037 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1039 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1040 void *object
, int active
) { return 1; }
1041 static inline void add_full(struct kmem_cache_node
*n
, struct page
*page
) {}
1042 static inline unsigned long kmem_cache_flags(unsigned long objsize
,
1043 unsigned long flags
, const char *name
,
1044 void (*ctor
)(struct kmem_cache
*, void *))
1048 #define slub_debug 0
1051 * Slab allocation and freeing
1053 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1056 int pages
= 1 << s
->order
;
1058 flags
|= s
->allocflags
;
1061 page
= alloc_pages(flags
, s
->order
);
1063 page
= alloc_pages_node(node
, flags
, s
->order
);
1068 mod_zone_page_state(page_zone(page
),
1069 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1070 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1076 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1079 setup_object_debug(s
, page
, object
);
1080 if (unlikely(s
->ctor
))
1084 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1087 struct kmem_cache_node
*n
;
1092 BUG_ON(flags
& GFP_SLAB_BUG_MASK
);
1094 page
= allocate_slab(s
,
1095 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1099 n
= get_node(s
, page_to_nid(page
));
1101 atomic_long_inc(&n
->nr_slabs
);
1103 page
->flags
|= 1 << PG_slab
;
1104 if (s
->flags
& (SLAB_DEBUG_FREE
| SLAB_RED_ZONE
| SLAB_POISON
|
1105 SLAB_STORE_USER
| SLAB_TRACE
))
1108 start
= page_address(page
);
1110 if (unlikely(s
->flags
& SLAB_POISON
))
1111 memset(start
, POISON_INUSE
, PAGE_SIZE
<< s
->order
);
1114 for_each_object(p
, s
, start
) {
1115 setup_object(s
, page
, last
);
1116 set_freepointer(s
, last
, p
);
1119 setup_object(s
, page
, last
);
1120 set_freepointer(s
, last
, NULL
);
1122 page
->freelist
= start
;
1128 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1130 int pages
= 1 << s
->order
;
1132 if (unlikely(SlabDebug(page
))) {
1135 slab_pad_check(s
, page
);
1136 for_each_object(p
, s
, page_address(page
))
1137 check_object(s
, page
, p
, 0);
1138 ClearSlabDebug(page
);
1141 mod_zone_page_state(page_zone(page
),
1142 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1143 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1146 __free_pages(page
, s
->order
);
1149 static void rcu_free_slab(struct rcu_head
*h
)
1153 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1154 __free_slab(page
->slab
, page
);
1157 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1159 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1161 * RCU free overloads the RCU head over the LRU
1163 struct rcu_head
*head
= (void *)&page
->lru
;
1165 call_rcu(head
, rcu_free_slab
);
1167 __free_slab(s
, page
);
1170 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1172 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1174 atomic_long_dec(&n
->nr_slabs
);
1175 reset_page_mapcount(page
);
1176 __ClearPageSlab(page
);
1181 * Per slab locking using the pagelock
1183 static __always_inline
void slab_lock(struct page
*page
)
1185 bit_spin_lock(PG_locked
, &page
->flags
);
1188 static __always_inline
void slab_unlock(struct page
*page
)
1190 __bit_spin_unlock(PG_locked
, &page
->flags
);
1193 static __always_inline
int slab_trylock(struct page
*page
)
1197 rc
= bit_spin_trylock(PG_locked
, &page
->flags
);
1202 * Management of partially allocated slabs
1204 static void add_partial(struct kmem_cache_node
*n
,
1205 struct page
*page
, int tail
)
1207 spin_lock(&n
->list_lock
);
1210 list_add_tail(&page
->lru
, &n
->partial
);
1212 list_add(&page
->lru
, &n
->partial
);
1213 spin_unlock(&n
->list_lock
);
1216 static void remove_partial(struct kmem_cache
*s
,
1219 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1221 spin_lock(&n
->list_lock
);
1222 list_del(&page
->lru
);
1224 spin_unlock(&n
->list_lock
);
1228 * Lock slab and remove from the partial list.
1230 * Must hold list_lock.
1232 static inline int lock_and_freeze_slab(struct kmem_cache_node
*n
, struct page
*page
)
1234 if (slab_trylock(page
)) {
1235 list_del(&page
->lru
);
1237 SetSlabFrozen(page
);
1244 * Try to allocate a partial slab from a specific node.
1246 static struct page
*get_partial_node(struct kmem_cache_node
*n
)
1251 * Racy check. If we mistakenly see no partial slabs then we
1252 * just allocate an empty slab. If we mistakenly try to get a
1253 * partial slab and there is none available then get_partials()
1256 if (!n
|| !n
->nr_partial
)
1259 spin_lock(&n
->list_lock
);
1260 list_for_each_entry(page
, &n
->partial
, lru
)
1261 if (lock_and_freeze_slab(n
, page
))
1265 spin_unlock(&n
->list_lock
);
1270 * Get a page from somewhere. Search in increasing NUMA distances.
1272 static struct page
*get_any_partial(struct kmem_cache
*s
, gfp_t flags
)
1275 struct zonelist
*zonelist
;
1280 * The defrag ratio allows a configuration of the tradeoffs between
1281 * inter node defragmentation and node local allocations. A lower
1282 * defrag_ratio increases the tendency to do local allocations
1283 * instead of attempting to obtain partial slabs from other nodes.
1285 * If the defrag_ratio is set to 0 then kmalloc() always
1286 * returns node local objects. If the ratio is higher then kmalloc()
1287 * may return off node objects because partial slabs are obtained
1288 * from other nodes and filled up.
1290 * If /sys/slab/xx/defrag_ratio is set to 100 (which makes
1291 * defrag_ratio = 1000) then every (well almost) allocation will
1292 * first attempt to defrag slab caches on other nodes. This means
1293 * scanning over all nodes to look for partial slabs which may be
1294 * expensive if we do it every time we are trying to find a slab
1295 * with available objects.
1297 if (!s
->remote_node_defrag_ratio
||
1298 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1301 zonelist
= &NODE_DATA(
1302 slab_node(current
->mempolicy
))->node_zonelists
[gfp_zone(flags
)];
1303 for (z
= zonelist
->zones
; *z
; z
++) {
1304 struct kmem_cache_node
*n
;
1306 n
= get_node(s
, zone_to_nid(*z
));
1308 if (n
&& cpuset_zone_allowed_hardwall(*z
, flags
) &&
1309 n
->nr_partial
> MIN_PARTIAL
) {
1310 page
= get_partial_node(n
);
1320 * Get a partial page, lock it and return it.
1322 static struct page
*get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
)
1325 int searchnode
= (node
== -1) ? numa_node_id() : node
;
1327 page
= get_partial_node(get_node(s
, searchnode
));
1328 if (page
|| (flags
& __GFP_THISNODE
))
1331 return get_any_partial(s
, flags
);
1335 * Move a page back to the lists.
1337 * Must be called with the slab lock held.
1339 * On exit the slab lock will have been dropped.
1341 static void unfreeze_slab(struct kmem_cache
*s
, struct page
*page
, int tail
)
1343 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1344 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, smp_processor_id());
1346 ClearSlabFrozen(page
);
1349 if (page
->freelist
) {
1350 add_partial(n
, page
, tail
);
1351 stat(c
, tail
? DEACTIVATE_TO_TAIL
: DEACTIVATE_TO_HEAD
);
1353 stat(c
, DEACTIVATE_FULL
);
1354 if (SlabDebug(page
) && (s
->flags
& SLAB_STORE_USER
))
1359 stat(c
, DEACTIVATE_EMPTY
);
1360 if (n
->nr_partial
< MIN_PARTIAL
) {
1362 * Adding an empty slab to the partial slabs in order
1363 * to avoid page allocator overhead. This slab needs
1364 * to come after the other slabs with objects in
1365 * order to fill them up. That way the size of the
1366 * partial list stays small. kmem_cache_shrink can
1367 * reclaim empty slabs from the partial list.
1369 add_partial(n
, page
, 1);
1373 stat(get_cpu_slab(s
, raw_smp_processor_id()), FREE_SLAB
);
1374 discard_slab(s
, page
);
1380 * Remove the cpu slab
1382 static void deactivate_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1384 struct page
*page
= c
->page
;
1388 stat(c
, DEACTIVATE_REMOTE_FREES
);
1390 * Merge cpu freelist into freelist. Typically we get here
1391 * because both freelists are empty. So this is unlikely
1394 while (unlikely(c
->freelist
)) {
1397 tail
= 0; /* Hot objects. Put the slab first */
1399 /* Retrieve object from cpu_freelist */
1400 object
= c
->freelist
;
1401 c
->freelist
= c
->freelist
[c
->offset
];
1403 /* And put onto the regular freelist */
1404 object
[c
->offset
] = page
->freelist
;
1405 page
->freelist
= object
;
1409 unfreeze_slab(s
, page
, tail
);
1412 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1414 stat(c
, CPUSLAB_FLUSH
);
1416 deactivate_slab(s
, c
);
1421 * Called from IPI handler with interrupts disabled.
1423 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
1425 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
1427 if (likely(c
&& c
->page
))
1431 static void flush_cpu_slab(void *d
)
1433 struct kmem_cache
*s
= d
;
1435 __flush_cpu_slab(s
, smp_processor_id());
1438 static void flush_all(struct kmem_cache
*s
)
1441 on_each_cpu(flush_cpu_slab
, s
, 1, 1);
1443 unsigned long flags
;
1445 local_irq_save(flags
);
1447 local_irq_restore(flags
);
1452 * Check if the objects in a per cpu structure fit numa
1453 * locality expectations.
1455 static inline int node_match(struct kmem_cache_cpu
*c
, int node
)
1458 if (node
!= -1 && c
->node
!= node
)
1465 * Slow path. The lockless freelist is empty or we need to perform
1468 * Interrupts are disabled.
1470 * Processing is still very fast if new objects have been freed to the
1471 * regular freelist. In that case we simply take over the regular freelist
1472 * as the lockless freelist and zap the regular freelist.
1474 * If that is not working then we fall back to the partial lists. We take the
1475 * first element of the freelist as the object to allocate now and move the
1476 * rest of the freelist to the lockless freelist.
1478 * And if we were unable to get a new slab from the partial slab lists then
1479 * we need to allocate a new slab. This is slowest path since we may sleep.
1481 static void *__slab_alloc(struct kmem_cache
*s
,
1482 gfp_t gfpflags
, int node
, void *addr
, struct kmem_cache_cpu
*c
)
1491 if (unlikely(!node_match(c
, node
)))
1493 stat(c
, ALLOC_REFILL
);
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
->offset
];
1503 c
->page
->inuse
= s
->objects
;
1504 c
->page
->freelist
= NULL
;
1505 c
->node
= page_to_nid(c
->page
);
1507 slab_unlock(c
->page
);
1508 stat(c
, ALLOC_SLOWPATH
);
1512 deactivate_slab(s
, c
);
1515 new = get_partial(s
, gfpflags
, node
);
1518 stat(c
, ALLOC_FROM_PARTIAL
);
1522 if (gfpflags
& __GFP_WAIT
)
1525 new = new_slab(s
, gfpflags
, node
);
1527 if (gfpflags
& __GFP_WAIT
)
1528 local_irq_disable();
1531 c
= get_cpu_slab(s
, smp_processor_id());
1532 stat(c
, ALLOC_SLAB
);
1542 * No memory available.
1544 * If the slab uses higher order allocs but the object is
1545 * smaller than a page size then we can fallback in emergencies
1546 * to the page allocator via kmalloc_large. The page allocator may
1547 * have failed to obtain a higher order page and we can try to
1548 * allocate a single page if the object fits into a single page.
1549 * That is only possible if certain conditions are met that are being
1550 * checked when a slab is created.
1552 if (!(gfpflags
& __GFP_NORETRY
) && (s
->flags
& __PAGE_ALLOC_FALLBACK
))
1553 return kmalloc_large(s
->objsize
, gfpflags
);
1557 object
= c
->page
->freelist
;
1558 if (!alloc_debug_processing(s
, c
->page
, object
, addr
))
1562 c
->page
->freelist
= object
[c
->offset
];
1568 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1569 * have the fastpath folded into their functions. So no function call
1570 * overhead for requests that can be satisfied on the fastpath.
1572 * The fastpath works by first checking if the lockless freelist can be used.
1573 * If not then __slab_alloc is called for slow processing.
1575 * Otherwise we can simply pick the next object from the lockless free list.
1577 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
1578 gfp_t gfpflags
, int node
, void *addr
)
1581 struct kmem_cache_cpu
*c
;
1582 unsigned long flags
;
1584 local_irq_save(flags
);
1585 c
= get_cpu_slab(s
, smp_processor_id());
1586 if (unlikely(!c
->freelist
|| !node_match(c
, node
)))
1588 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
1591 object
= c
->freelist
;
1592 c
->freelist
= object
[c
->offset
];
1593 stat(c
, ALLOC_FASTPATH
);
1595 local_irq_restore(flags
);
1597 if (unlikely((gfpflags
& __GFP_ZERO
) && object
))
1598 memset(object
, 0, c
->objsize
);
1603 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
1605 return slab_alloc(s
, gfpflags
, -1, __builtin_return_address(0));
1607 EXPORT_SYMBOL(kmem_cache_alloc
);
1610 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
1612 return slab_alloc(s
, gfpflags
, node
, __builtin_return_address(0));
1614 EXPORT_SYMBOL(kmem_cache_alloc_node
);
1618 * Slow patch handling. This may still be called frequently since objects
1619 * have a longer lifetime than the cpu slabs in most processing loads.
1621 * So we still attempt to reduce cache line usage. Just take the slab
1622 * lock and free the item. If there is no additional partial page
1623 * handling required then we can return immediately.
1625 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
1626 void *x
, void *addr
, unsigned int offset
)
1629 void **object
= (void *)x
;
1630 struct kmem_cache_cpu
*c
;
1632 c
= get_cpu_slab(s
, raw_smp_processor_id());
1633 stat(c
, FREE_SLOWPATH
);
1636 if (unlikely(SlabDebug(page
)))
1639 prior
= object
[offset
] = page
->freelist
;
1640 page
->freelist
= object
;
1643 if (unlikely(SlabFrozen(page
))) {
1644 stat(c
, FREE_FROZEN
);
1648 if (unlikely(!page
->inuse
))
1652 * Objects left in the slab. If it
1653 * was not on the partial list before
1656 if (unlikely(!prior
)) {
1657 add_partial(get_node(s
, page_to_nid(page
)), page
, 1);
1658 stat(c
, FREE_ADD_PARTIAL
);
1668 * Slab still on the partial list.
1670 remove_partial(s
, page
);
1671 stat(c
, FREE_REMOVE_PARTIAL
);
1675 discard_slab(s
, page
);
1679 if (!free_debug_processing(s
, page
, x
, addr
))
1685 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1686 * can perform fastpath freeing without additional function calls.
1688 * The fastpath is only possible if we are freeing to the current cpu slab
1689 * of this processor. This typically the case if we have just allocated
1692 * If fastpath is not possible then fall back to __slab_free where we deal
1693 * with all sorts of special processing.
1695 static __always_inline
void slab_free(struct kmem_cache
*s
,
1696 struct page
*page
, void *x
, void *addr
)
1698 void **object
= (void *)x
;
1699 struct kmem_cache_cpu
*c
;
1700 unsigned long flags
;
1702 local_irq_save(flags
);
1703 debug_check_no_locks_freed(object
, s
->objsize
);
1704 c
= get_cpu_slab(s
, smp_processor_id());
1705 if (likely(page
== c
->page
&& c
->node
>= 0)) {
1706 object
[c
->offset
] = c
->freelist
;
1707 c
->freelist
= object
;
1708 stat(c
, FREE_FASTPATH
);
1710 __slab_free(s
, page
, x
, addr
, c
->offset
);
1712 local_irq_restore(flags
);
1715 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
1719 page
= virt_to_head_page(x
);
1721 slab_free(s
, page
, x
, __builtin_return_address(0));
1723 EXPORT_SYMBOL(kmem_cache_free
);
1725 /* Figure out on which slab object the object resides */
1726 static struct page
*get_object_page(const void *x
)
1728 struct page
*page
= virt_to_head_page(x
);
1730 if (!PageSlab(page
))
1737 * Object placement in a slab is made very easy because we always start at
1738 * offset 0. If we tune the size of the object to the alignment then we can
1739 * get the required alignment by putting one properly sized object after
1742 * Notice that the allocation order determines the sizes of the per cpu
1743 * caches. Each processor has always one slab available for allocations.
1744 * Increasing the allocation order reduces the number of times that slabs
1745 * must be moved on and off the partial lists and is therefore a factor in
1750 * Mininum / Maximum order of slab pages. This influences locking overhead
1751 * and slab fragmentation. A higher order reduces the number of partial slabs
1752 * and increases the number of allocations possible without having to
1753 * take the list_lock.
1755 static int slub_min_order
;
1756 static int slub_max_order
= DEFAULT_MAX_ORDER
;
1757 static int slub_min_objects
= DEFAULT_MIN_OBJECTS
;
1760 * Merge control. If this is set then no merging of slab caches will occur.
1761 * (Could be removed. This was introduced to pacify the merge skeptics.)
1763 static int slub_nomerge
;
1766 * Calculate the order of allocation given an slab object size.
1768 * The order of allocation has significant impact on performance and other
1769 * system components. Generally order 0 allocations should be preferred since
1770 * order 0 does not cause fragmentation in the page allocator. Larger objects
1771 * be problematic to put into order 0 slabs because there may be too much
1772 * unused space left. We go to a higher order if more than 1/8th of the slab
1775 * In order to reach satisfactory performance we must ensure that a minimum
1776 * number of objects is in one slab. Otherwise we may generate too much
1777 * activity on the partial lists which requires taking the list_lock. This is
1778 * less a concern for large slabs though which are rarely used.
1780 * slub_max_order specifies the order where we begin to stop considering the
1781 * number of objects in a slab as critical. If we reach slub_max_order then
1782 * we try to keep the page order as low as possible. So we accept more waste
1783 * of space in favor of a small page order.
1785 * Higher order allocations also allow the placement of more objects in a
1786 * slab and thereby reduce object handling overhead. If the user has
1787 * requested a higher mininum order then we start with that one instead of
1788 * the smallest order which will fit the object.
1790 static inline int slab_order(int size
, int min_objects
,
1791 int max_order
, int fract_leftover
)
1795 int min_order
= slub_min_order
;
1797 for (order
= max(min_order
,
1798 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
1799 order
<= max_order
; order
++) {
1801 unsigned long slab_size
= PAGE_SIZE
<< order
;
1803 if (slab_size
< min_objects
* size
)
1806 rem
= slab_size
% size
;
1808 if (rem
<= slab_size
/ fract_leftover
)
1816 static inline int calculate_order(int size
)
1823 * Attempt to find best configuration for a slab. This
1824 * works by first attempting to generate a layout with
1825 * the best configuration and backing off gradually.
1827 * First we reduce the acceptable waste in a slab. Then
1828 * we reduce the minimum objects required in a slab.
1830 min_objects
= slub_min_objects
;
1831 while (min_objects
> 1) {
1833 while (fraction
>= 4) {
1834 order
= slab_order(size
, min_objects
,
1835 slub_max_order
, fraction
);
1836 if (order
<= slub_max_order
)
1844 * We were unable to place multiple objects in a slab. Now
1845 * lets see if we can place a single object there.
1847 order
= slab_order(size
, 1, slub_max_order
, 1);
1848 if (order
<= slub_max_order
)
1852 * Doh this slab cannot be placed using slub_max_order.
1854 order
= slab_order(size
, 1, MAX_ORDER
, 1);
1855 if (order
<= MAX_ORDER
)
1861 * Figure out what the alignment of the objects will be.
1863 static unsigned long calculate_alignment(unsigned long flags
,
1864 unsigned long align
, unsigned long size
)
1867 * If the user wants hardware cache aligned objects then
1868 * follow that suggestion if the object is sufficiently
1871 * The hardware cache alignment cannot override the
1872 * specified alignment though. If that is greater
1875 if ((flags
& SLAB_HWCACHE_ALIGN
) &&
1876 size
> cache_line_size() / 2)
1877 return max_t(unsigned long, align
, cache_line_size());
1879 if (align
< ARCH_SLAB_MINALIGN
)
1880 return ARCH_SLAB_MINALIGN
;
1882 return ALIGN(align
, sizeof(void *));
1885 static void init_kmem_cache_cpu(struct kmem_cache
*s
,
1886 struct kmem_cache_cpu
*c
)
1891 c
->offset
= s
->offset
/ sizeof(void *);
1892 c
->objsize
= s
->objsize
;
1895 static void init_kmem_cache_node(struct kmem_cache_node
*n
)
1898 atomic_long_set(&n
->nr_slabs
, 0);
1899 spin_lock_init(&n
->list_lock
);
1900 INIT_LIST_HEAD(&n
->partial
);
1901 #ifdef CONFIG_SLUB_DEBUG
1902 INIT_LIST_HEAD(&n
->full
);
1908 * Per cpu array for per cpu structures.
1910 * The per cpu array places all kmem_cache_cpu structures from one processor
1911 * close together meaning that it becomes possible that multiple per cpu
1912 * structures are contained in one cacheline. This may be particularly
1913 * beneficial for the kmalloc caches.
1915 * A desktop system typically has around 60-80 slabs. With 100 here we are
1916 * likely able to get per cpu structures for all caches from the array defined
1917 * here. We must be able to cover all kmalloc caches during bootstrap.
1919 * If the per cpu array is exhausted then fall back to kmalloc
1920 * of individual cachelines. No sharing is possible then.
1922 #define NR_KMEM_CACHE_CPU 100
1924 static DEFINE_PER_CPU(struct kmem_cache_cpu
,
1925 kmem_cache_cpu
)[NR_KMEM_CACHE_CPU
];
1927 static DEFINE_PER_CPU(struct kmem_cache_cpu
*, kmem_cache_cpu_free
);
1928 static cpumask_t kmem_cach_cpu_free_init_once
= CPU_MASK_NONE
;
1930 static struct kmem_cache_cpu
*alloc_kmem_cache_cpu(struct kmem_cache
*s
,
1931 int cpu
, gfp_t flags
)
1933 struct kmem_cache_cpu
*c
= per_cpu(kmem_cache_cpu_free
, cpu
);
1936 per_cpu(kmem_cache_cpu_free
, cpu
) =
1937 (void *)c
->freelist
;
1939 /* Table overflow: So allocate ourselves */
1941 ALIGN(sizeof(struct kmem_cache_cpu
), cache_line_size()),
1942 flags
, cpu_to_node(cpu
));
1947 init_kmem_cache_cpu(s
, c
);
1951 static void free_kmem_cache_cpu(struct kmem_cache_cpu
*c
, int cpu
)
1953 if (c
< per_cpu(kmem_cache_cpu
, cpu
) ||
1954 c
> per_cpu(kmem_cache_cpu
, cpu
) + NR_KMEM_CACHE_CPU
) {
1958 c
->freelist
= (void *)per_cpu(kmem_cache_cpu_free
, cpu
);
1959 per_cpu(kmem_cache_cpu_free
, cpu
) = c
;
1962 static void free_kmem_cache_cpus(struct kmem_cache
*s
)
1966 for_each_online_cpu(cpu
) {
1967 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
1970 s
->cpu_slab
[cpu
] = NULL
;
1971 free_kmem_cache_cpu(c
, cpu
);
1976 static int alloc_kmem_cache_cpus(struct kmem_cache
*s
, gfp_t flags
)
1980 for_each_online_cpu(cpu
) {
1981 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
1986 c
= alloc_kmem_cache_cpu(s
, cpu
, flags
);
1988 free_kmem_cache_cpus(s
);
1991 s
->cpu_slab
[cpu
] = c
;
1997 * Initialize the per cpu array.
1999 static void init_alloc_cpu_cpu(int cpu
)
2003 if (cpu_isset(cpu
, kmem_cach_cpu_free_init_once
))
2006 for (i
= NR_KMEM_CACHE_CPU
- 1; i
>= 0; i
--)
2007 free_kmem_cache_cpu(&per_cpu(kmem_cache_cpu
, cpu
)[i
], cpu
);
2009 cpu_set(cpu
, kmem_cach_cpu_free_init_once
);
2012 static void __init
init_alloc_cpu(void)
2016 for_each_online_cpu(cpu
)
2017 init_alloc_cpu_cpu(cpu
);
2021 static inline void free_kmem_cache_cpus(struct kmem_cache
*s
) {}
2022 static inline void init_alloc_cpu(void) {}
2024 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
, gfp_t flags
)
2026 init_kmem_cache_cpu(s
, &s
->cpu_slab
);
2033 * No kmalloc_node yet so do it by hand. We know that this is the first
2034 * slab on the node for this slabcache. There are no concurrent accesses
2037 * Note that this function only works on the kmalloc_node_cache
2038 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2039 * memory on a fresh node that has no slab structures yet.
2041 static struct kmem_cache_node
*early_kmem_cache_node_alloc(gfp_t gfpflags
,
2045 struct kmem_cache_node
*n
;
2046 unsigned long flags
;
2048 BUG_ON(kmalloc_caches
->size
< sizeof(struct kmem_cache_node
));
2050 page
= new_slab(kmalloc_caches
, gfpflags
, node
);
2053 if (page_to_nid(page
) != node
) {
2054 printk(KERN_ERR
"SLUB: Unable to allocate memory from "
2056 printk(KERN_ERR
"SLUB: Allocating a useless per node structure "
2057 "in order to be able to continue\n");
2062 page
->freelist
= get_freepointer(kmalloc_caches
, n
);
2064 kmalloc_caches
->node
[node
] = n
;
2065 #ifdef CONFIG_SLUB_DEBUG
2066 init_object(kmalloc_caches
, n
, 1);
2067 init_tracking(kmalloc_caches
, n
);
2069 init_kmem_cache_node(n
);
2070 atomic_long_inc(&n
->nr_slabs
);
2072 * lockdep requires consistent irq usage for each lock
2073 * so even though there cannot be a race this early in
2074 * the boot sequence, we still disable irqs.
2076 local_irq_save(flags
);
2077 add_partial(n
, page
, 0);
2078 local_irq_restore(flags
);
2082 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2086 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2087 struct kmem_cache_node
*n
= s
->node
[node
];
2088 if (n
&& n
!= &s
->local_node
)
2089 kmem_cache_free(kmalloc_caches
, n
);
2090 s
->node
[node
] = NULL
;
2094 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
2099 if (slab_state
>= UP
)
2100 local_node
= page_to_nid(virt_to_page(s
));
2104 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2105 struct kmem_cache_node
*n
;
2107 if (local_node
== node
)
2110 if (slab_state
== DOWN
) {
2111 n
= early_kmem_cache_node_alloc(gfpflags
,
2115 n
= kmem_cache_alloc_node(kmalloc_caches
,
2119 free_kmem_cache_nodes(s
);
2125 init_kmem_cache_node(n
);
2130 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2134 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
2136 init_kmem_cache_node(&s
->local_node
);
2142 * calculate_sizes() determines the order and the distribution of data within
2145 static int calculate_sizes(struct kmem_cache
*s
)
2147 unsigned long flags
= s
->flags
;
2148 unsigned long size
= s
->objsize
;
2149 unsigned long align
= s
->align
;
2152 * Determine if we can poison the object itself. If the user of
2153 * the slab may touch the object after free or before allocation
2154 * then we should never poison the object itself.
2156 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
2158 s
->flags
|= __OBJECT_POISON
;
2160 s
->flags
&= ~__OBJECT_POISON
;
2163 * Round up object size to the next word boundary. We can only
2164 * place the free pointer at word boundaries and this determines
2165 * the possible location of the free pointer.
2167 size
= ALIGN(size
, sizeof(void *));
2169 #ifdef CONFIG_SLUB_DEBUG
2171 * If we are Redzoning then check if there is some space between the
2172 * end of the object and the free pointer. If not then add an
2173 * additional word to have some bytes to store Redzone information.
2175 if ((flags
& SLAB_RED_ZONE
) && size
== s
->objsize
)
2176 size
+= sizeof(void *);
2180 * With that we have determined the number of bytes in actual use
2181 * by the object. This is the potential offset to the free pointer.
2185 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
2188 * Relocate free pointer after the object if it is not
2189 * permitted to overwrite the first word of the object on
2192 * This is the case if we do RCU, have a constructor or
2193 * destructor or are poisoning the objects.
2196 size
+= sizeof(void *);
2199 #ifdef CONFIG_SLUB_DEBUG
2200 if (flags
& SLAB_STORE_USER
)
2202 * Need to store information about allocs and frees after
2205 size
+= 2 * sizeof(struct track
);
2207 if (flags
& SLAB_RED_ZONE
)
2209 * Add some empty padding so that we can catch
2210 * overwrites from earlier objects rather than let
2211 * tracking information or the free pointer be
2212 * corrupted if an user writes before the start
2215 size
+= sizeof(void *);
2219 * Determine the alignment based on various parameters that the
2220 * user specified and the dynamic determination of cache line size
2223 align
= calculate_alignment(flags
, align
, s
->objsize
);
2226 * SLUB stores one object immediately after another beginning from
2227 * offset 0. In order to align the objects we have to simply size
2228 * each object to conform to the alignment.
2230 size
= ALIGN(size
, align
);
2233 if ((flags
& __KMALLOC_CACHE
) &&
2234 PAGE_SIZE
/ size
< slub_min_objects
) {
2236 * Kmalloc cache that would not have enough objects in
2237 * an order 0 page. Kmalloc slabs can fallback to
2238 * page allocator order 0 allocs so take a reasonably large
2239 * order that will allows us a good number of objects.
2241 s
->order
= max(slub_max_order
, PAGE_ALLOC_COSTLY_ORDER
);
2242 s
->flags
|= __PAGE_ALLOC_FALLBACK
;
2243 s
->allocflags
|= __GFP_NOWARN
;
2245 s
->order
= calculate_order(size
);
2252 s
->allocflags
|= __GFP_COMP
;
2254 if (s
->flags
& SLAB_CACHE_DMA
)
2255 s
->allocflags
|= SLUB_DMA
;
2257 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
2258 s
->allocflags
|= __GFP_RECLAIMABLE
;
2261 * Determine the number of objects per slab
2263 s
->objects
= (PAGE_SIZE
<< s
->order
) / size
;
2265 return !!s
->objects
;
2269 static int kmem_cache_open(struct kmem_cache
*s
, gfp_t gfpflags
,
2270 const char *name
, size_t size
,
2271 size_t align
, unsigned long flags
,
2272 void (*ctor
)(struct kmem_cache
*, void *))
2274 memset(s
, 0, kmem_size
);
2279 s
->flags
= kmem_cache_flags(size
, flags
, name
, ctor
);
2281 if (!calculate_sizes(s
))
2286 s
->remote_node_defrag_ratio
= 100;
2288 if (!init_kmem_cache_nodes(s
, gfpflags
& ~SLUB_DMA
))
2291 if (alloc_kmem_cache_cpus(s
, gfpflags
& ~SLUB_DMA
))
2293 free_kmem_cache_nodes(s
);
2295 if (flags
& SLAB_PANIC
)
2296 panic("Cannot create slab %s size=%lu realsize=%u "
2297 "order=%u offset=%u flags=%lx\n",
2298 s
->name
, (unsigned long)size
, s
->size
, s
->order
,
2304 * Check if a given pointer is valid
2306 int kmem_ptr_validate(struct kmem_cache
*s
, const void *object
)
2310 page
= get_object_page(object
);
2312 if (!page
|| s
!= page
->slab
)
2313 /* No slab or wrong slab */
2316 if (!check_valid_pointer(s
, page
, object
))
2320 * We could also check if the object is on the slabs freelist.
2321 * But this would be too expensive and it seems that the main
2322 * purpose of kmem_ptr_valid is to check if the object belongs
2323 * to a certain slab.
2327 EXPORT_SYMBOL(kmem_ptr_validate
);
2330 * Determine the size of a slab object
2332 unsigned int kmem_cache_size(struct kmem_cache
*s
)
2336 EXPORT_SYMBOL(kmem_cache_size
);
2338 const char *kmem_cache_name(struct kmem_cache
*s
)
2342 EXPORT_SYMBOL(kmem_cache_name
);
2345 * Attempt to free all slabs on a node. Return the number of slabs we
2346 * were unable to free.
2348 static int free_list(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
2349 struct list_head
*list
)
2351 int slabs_inuse
= 0;
2352 unsigned long flags
;
2353 struct page
*page
, *h
;
2355 spin_lock_irqsave(&n
->list_lock
, flags
);
2356 list_for_each_entry_safe(page
, h
, list
, lru
)
2358 list_del(&page
->lru
);
2359 discard_slab(s
, page
);
2362 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2367 * Release all resources used by a slab cache.
2369 static inline int kmem_cache_close(struct kmem_cache
*s
)
2375 /* Attempt to free all objects */
2376 free_kmem_cache_cpus(s
);
2377 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2378 struct kmem_cache_node
*n
= get_node(s
, node
);
2380 n
->nr_partial
-= free_list(s
, n
, &n
->partial
);
2381 if (atomic_long_read(&n
->nr_slabs
))
2384 free_kmem_cache_nodes(s
);
2389 * Close a cache and release the kmem_cache structure
2390 * (must be used for caches created using kmem_cache_create)
2392 void kmem_cache_destroy(struct kmem_cache
*s
)
2394 down_write(&slub_lock
);
2398 up_write(&slub_lock
);
2399 if (kmem_cache_close(s
))
2401 sysfs_slab_remove(s
);
2403 up_write(&slub_lock
);
2405 EXPORT_SYMBOL(kmem_cache_destroy
);
2407 /********************************************************************
2409 *******************************************************************/
2411 struct kmem_cache kmalloc_caches
[PAGE_SHIFT
+ 1] __cacheline_aligned
;
2412 EXPORT_SYMBOL(kmalloc_caches
);
2414 #ifdef CONFIG_ZONE_DMA
2415 static struct kmem_cache
*kmalloc_caches_dma
[PAGE_SHIFT
+ 1];
2418 static int __init
setup_slub_min_order(char *str
)
2420 get_option(&str
, &slub_min_order
);
2425 __setup("slub_min_order=", setup_slub_min_order
);
2427 static int __init
setup_slub_max_order(char *str
)
2429 get_option(&str
, &slub_max_order
);
2434 __setup("slub_max_order=", setup_slub_max_order
);
2436 static int __init
setup_slub_min_objects(char *str
)
2438 get_option(&str
, &slub_min_objects
);
2443 __setup("slub_min_objects=", setup_slub_min_objects
);
2445 static int __init
setup_slub_nomerge(char *str
)
2451 __setup("slub_nomerge", setup_slub_nomerge
);
2453 static struct kmem_cache
*create_kmalloc_cache(struct kmem_cache
*s
,
2454 const char *name
, int size
, gfp_t gfp_flags
)
2456 unsigned int flags
= 0;
2458 if (gfp_flags
& SLUB_DMA
)
2459 flags
= SLAB_CACHE_DMA
;
2461 down_write(&slub_lock
);
2462 if (!kmem_cache_open(s
, gfp_flags
, name
, size
, ARCH_KMALLOC_MINALIGN
,
2463 flags
| __KMALLOC_CACHE
, NULL
))
2466 list_add(&s
->list
, &slab_caches
);
2467 up_write(&slub_lock
);
2468 if (sysfs_slab_add(s
))
2473 panic("Creation of kmalloc slab %s size=%d failed.\n", name
, size
);
2476 #ifdef CONFIG_ZONE_DMA
2478 static void sysfs_add_func(struct work_struct
*w
)
2480 struct kmem_cache
*s
;
2482 down_write(&slub_lock
);
2483 list_for_each_entry(s
, &slab_caches
, list
) {
2484 if (s
->flags
& __SYSFS_ADD_DEFERRED
) {
2485 s
->flags
&= ~__SYSFS_ADD_DEFERRED
;
2489 up_write(&slub_lock
);
2492 static DECLARE_WORK(sysfs_add_work
, sysfs_add_func
);
2494 static noinline
struct kmem_cache
*dma_kmalloc_cache(int index
, gfp_t flags
)
2496 struct kmem_cache
*s
;
2500 s
= kmalloc_caches_dma
[index
];
2504 /* Dynamically create dma cache */
2505 if (flags
& __GFP_WAIT
)
2506 down_write(&slub_lock
);
2508 if (!down_write_trylock(&slub_lock
))
2512 if (kmalloc_caches_dma
[index
])
2515 realsize
= kmalloc_caches
[index
].objsize
;
2516 text
= kasprintf(flags
& ~SLUB_DMA
, "kmalloc_dma-%d",
2517 (unsigned int)realsize
);
2518 s
= kmalloc(kmem_size
, flags
& ~SLUB_DMA
);
2520 if (!s
|| !text
|| !kmem_cache_open(s
, flags
, text
,
2521 realsize
, ARCH_KMALLOC_MINALIGN
,
2522 SLAB_CACHE_DMA
|__SYSFS_ADD_DEFERRED
, NULL
)) {
2528 list_add(&s
->list
, &slab_caches
);
2529 kmalloc_caches_dma
[index
] = s
;
2531 schedule_work(&sysfs_add_work
);
2534 up_write(&slub_lock
);
2536 return kmalloc_caches_dma
[index
];
2541 * Conversion table for small slabs sizes / 8 to the index in the
2542 * kmalloc array. This is necessary for slabs < 192 since we have non power
2543 * of two cache sizes there. The size of larger slabs can be determined using
2546 static s8 size_index
[24] = {
2573 static struct kmem_cache
*get_slab(size_t size
, gfp_t flags
)
2579 return ZERO_SIZE_PTR
;
2581 index
= size_index
[(size
- 1) / 8];
2583 index
= fls(size
- 1);
2585 #ifdef CONFIG_ZONE_DMA
2586 if (unlikely((flags
& SLUB_DMA
)))
2587 return dma_kmalloc_cache(index
, flags
);
2590 return &kmalloc_caches
[index
];
2593 void *__kmalloc(size_t size
, gfp_t flags
)
2595 struct kmem_cache
*s
;
2597 if (unlikely(size
> PAGE_SIZE
))
2598 return kmalloc_large(size
, flags
);
2600 s
= get_slab(size
, flags
);
2602 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2605 return slab_alloc(s
, flags
, -1, __builtin_return_address(0));
2607 EXPORT_SYMBOL(__kmalloc
);
2610 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
2612 struct kmem_cache
*s
;
2614 if (unlikely(size
> PAGE_SIZE
))
2615 return kmalloc_large(size
, flags
);
2617 s
= get_slab(size
, flags
);
2619 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2622 return slab_alloc(s
, flags
, node
, __builtin_return_address(0));
2624 EXPORT_SYMBOL(__kmalloc_node
);
2627 size_t ksize(const void *object
)
2630 struct kmem_cache
*s
;
2633 if (unlikely(object
== ZERO_SIZE_PTR
))
2636 page
= virt_to_head_page(object
);
2639 if (unlikely(!PageSlab(page
)))
2640 return PAGE_SIZE
<< compound_order(page
);
2646 * Debugging requires use of the padding between object
2647 * and whatever may come after it.
2649 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
2653 * If we have the need to store the freelist pointer
2654 * back there or track user information then we can
2655 * only use the space before that information.
2657 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
2661 * Else we can use all the padding etc for the allocation
2665 EXPORT_SYMBOL(ksize
);
2667 void kfree(const void *x
)
2670 void *object
= (void *)x
;
2672 if (unlikely(ZERO_OR_NULL_PTR(x
)))
2675 page
= virt_to_head_page(x
);
2676 if (unlikely(!PageSlab(page
))) {
2680 slab_free(page
->slab
, page
, object
, __builtin_return_address(0));
2682 EXPORT_SYMBOL(kfree
);
2684 static unsigned long count_partial(struct kmem_cache_node
*n
)
2686 unsigned long flags
;
2687 unsigned long x
= 0;
2690 spin_lock_irqsave(&n
->list_lock
, flags
);
2691 list_for_each_entry(page
, &n
->partial
, lru
)
2693 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2698 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2699 * the remaining slabs by the number of items in use. The slabs with the
2700 * most items in use come first. New allocations will then fill those up
2701 * and thus they can be removed from the partial lists.
2703 * The slabs with the least items are placed last. This results in them
2704 * being allocated from last increasing the chance that the last objects
2705 * are freed in them.
2707 int kmem_cache_shrink(struct kmem_cache
*s
)
2711 struct kmem_cache_node
*n
;
2714 struct list_head
*slabs_by_inuse
=
2715 kmalloc(sizeof(struct list_head
) * s
->objects
, GFP_KERNEL
);
2716 unsigned long flags
;
2718 if (!slabs_by_inuse
)
2722 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2723 n
= get_node(s
, node
);
2728 for (i
= 0; i
< s
->objects
; i
++)
2729 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
2731 spin_lock_irqsave(&n
->list_lock
, flags
);
2734 * Build lists indexed by the items in use in each slab.
2736 * Note that concurrent frees may occur while we hold the
2737 * list_lock. page->inuse here is the upper limit.
2739 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
2740 if (!page
->inuse
&& slab_trylock(page
)) {
2742 * Must hold slab lock here because slab_free
2743 * may have freed the last object and be
2744 * waiting to release the slab.
2746 list_del(&page
->lru
);
2749 discard_slab(s
, page
);
2751 list_move(&page
->lru
,
2752 slabs_by_inuse
+ page
->inuse
);
2757 * Rebuild the partial list with the slabs filled up most
2758 * first and the least used slabs at the end.
2760 for (i
= s
->objects
- 1; i
>= 0; i
--)
2761 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
2763 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2766 kfree(slabs_by_inuse
);
2769 EXPORT_SYMBOL(kmem_cache_shrink
);
2771 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
2772 static int slab_mem_going_offline_callback(void *arg
)
2774 struct kmem_cache
*s
;
2776 down_read(&slub_lock
);
2777 list_for_each_entry(s
, &slab_caches
, list
)
2778 kmem_cache_shrink(s
);
2779 up_read(&slub_lock
);
2784 static void slab_mem_offline_callback(void *arg
)
2786 struct kmem_cache_node
*n
;
2787 struct kmem_cache
*s
;
2788 struct memory_notify
*marg
= arg
;
2791 offline_node
= marg
->status_change_nid
;
2794 * If the node still has available memory. we need kmem_cache_node
2797 if (offline_node
< 0)
2800 down_read(&slub_lock
);
2801 list_for_each_entry(s
, &slab_caches
, list
) {
2802 n
= get_node(s
, offline_node
);
2805 * if n->nr_slabs > 0, slabs still exist on the node
2806 * that is going down. We were unable to free them,
2807 * and offline_pages() function shoudn't call this
2808 * callback. So, we must fail.
2810 BUG_ON(atomic_long_read(&n
->nr_slabs
));
2812 s
->node
[offline_node
] = NULL
;
2813 kmem_cache_free(kmalloc_caches
, n
);
2816 up_read(&slub_lock
);
2819 static int slab_mem_going_online_callback(void *arg
)
2821 struct kmem_cache_node
*n
;
2822 struct kmem_cache
*s
;
2823 struct memory_notify
*marg
= arg
;
2824 int nid
= marg
->status_change_nid
;
2828 * If the node's memory is already available, then kmem_cache_node is
2829 * already created. Nothing to do.
2835 * We are bringing a node online. No memory is availabe yet. We must
2836 * allocate a kmem_cache_node structure in order to bring the node
2839 down_read(&slub_lock
);
2840 list_for_each_entry(s
, &slab_caches
, list
) {
2842 * XXX: kmem_cache_alloc_node will fallback to other nodes
2843 * since memory is not yet available from the node that
2846 n
= kmem_cache_alloc(kmalloc_caches
, GFP_KERNEL
);
2851 init_kmem_cache_node(n
);
2855 up_read(&slub_lock
);
2859 static int slab_memory_callback(struct notifier_block
*self
,
2860 unsigned long action
, void *arg
)
2865 case MEM_GOING_ONLINE
:
2866 ret
= slab_mem_going_online_callback(arg
);
2868 case MEM_GOING_OFFLINE
:
2869 ret
= slab_mem_going_offline_callback(arg
);
2872 case MEM_CANCEL_ONLINE
:
2873 slab_mem_offline_callback(arg
);
2876 case MEM_CANCEL_OFFLINE
:
2880 ret
= notifier_from_errno(ret
);
2884 #endif /* CONFIG_MEMORY_HOTPLUG */
2886 /********************************************************************
2887 * Basic setup of slabs
2888 *******************************************************************/
2890 void __init
kmem_cache_init(void)
2899 * Must first have the slab cache available for the allocations of the
2900 * struct kmem_cache_node's. There is special bootstrap code in
2901 * kmem_cache_open for slab_state == DOWN.
2903 create_kmalloc_cache(&kmalloc_caches
[0], "kmem_cache_node",
2904 sizeof(struct kmem_cache_node
), GFP_KERNEL
);
2905 kmalloc_caches
[0].refcount
= -1;
2908 hotplug_memory_notifier(slab_memory_callback
, 1);
2911 /* Able to allocate the per node structures */
2912 slab_state
= PARTIAL
;
2914 /* Caches that are not of the two-to-the-power-of size */
2915 if (KMALLOC_MIN_SIZE
<= 64) {
2916 create_kmalloc_cache(&kmalloc_caches
[1],
2917 "kmalloc-96", 96, GFP_KERNEL
);
2920 if (KMALLOC_MIN_SIZE
<= 128) {
2921 create_kmalloc_cache(&kmalloc_caches
[2],
2922 "kmalloc-192", 192, GFP_KERNEL
);
2926 for (i
= KMALLOC_SHIFT_LOW
; i
<= PAGE_SHIFT
; i
++) {
2927 create_kmalloc_cache(&kmalloc_caches
[i
],
2928 "kmalloc", 1 << i
, GFP_KERNEL
);
2934 * Patch up the size_index table if we have strange large alignment
2935 * requirements for the kmalloc array. This is only the case for
2936 * mips it seems. The standard arches will not generate any code here.
2938 * Largest permitted alignment is 256 bytes due to the way we
2939 * handle the index determination for the smaller caches.
2941 * Make sure that nothing crazy happens if someone starts tinkering
2942 * around with ARCH_KMALLOC_MINALIGN
2944 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 256 ||
2945 (KMALLOC_MIN_SIZE
& (KMALLOC_MIN_SIZE
- 1)));
2947 for (i
= 8; i
< KMALLOC_MIN_SIZE
; i
+= 8)
2948 size_index
[(i
- 1) / 8] = KMALLOC_SHIFT_LOW
;
2952 /* Provide the correct kmalloc names now that the caches are up */
2953 for (i
= KMALLOC_SHIFT_LOW
; i
<= PAGE_SHIFT
; i
++)
2954 kmalloc_caches
[i
]. name
=
2955 kasprintf(GFP_KERNEL
, "kmalloc-%d", 1 << i
);
2958 register_cpu_notifier(&slab_notifier
);
2959 kmem_size
= offsetof(struct kmem_cache
, cpu_slab
) +
2960 nr_cpu_ids
* sizeof(struct kmem_cache_cpu
*);
2962 kmem_size
= sizeof(struct kmem_cache
);
2967 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
2968 " CPUs=%d, Nodes=%d\n",
2969 caches
, cache_line_size(),
2970 slub_min_order
, slub_max_order
, slub_min_objects
,
2971 nr_cpu_ids
, nr_node_ids
);
2975 * Find a mergeable slab cache
2977 static int slab_unmergeable(struct kmem_cache
*s
)
2979 if (slub_nomerge
|| (s
->flags
& SLUB_NEVER_MERGE
))
2982 if ((s
->flags
& __PAGE_ALLOC_FALLBACK
))
2989 * We may have set a slab to be unmergeable during bootstrap.
2991 if (s
->refcount
< 0)
2997 static struct kmem_cache
*find_mergeable(size_t size
,
2998 size_t align
, unsigned long flags
, const char *name
,
2999 void (*ctor
)(struct kmem_cache
*, void *))
3001 struct kmem_cache
*s
;
3003 if (slub_nomerge
|| (flags
& SLUB_NEVER_MERGE
))
3009 size
= ALIGN(size
, sizeof(void *));
3010 align
= calculate_alignment(flags
, align
, size
);
3011 size
= ALIGN(size
, align
);
3012 flags
= kmem_cache_flags(size
, flags
, name
, NULL
);
3014 list_for_each_entry(s
, &slab_caches
, list
) {
3015 if (slab_unmergeable(s
))
3021 if ((flags
& SLUB_MERGE_SAME
) != (s
->flags
& SLUB_MERGE_SAME
))
3024 * Check if alignment is compatible.
3025 * Courtesy of Adrian Drzewiecki
3027 if ((s
->size
& ~(align
- 1)) != s
->size
)
3030 if (s
->size
- size
>= sizeof(void *))
3038 struct kmem_cache
*kmem_cache_create(const char *name
, size_t size
,
3039 size_t align
, unsigned long flags
,
3040 void (*ctor
)(struct kmem_cache
*, void *))
3042 struct kmem_cache
*s
;
3044 down_write(&slub_lock
);
3045 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3051 * Adjust the object sizes so that we clear
3052 * the complete object on kzalloc.
3054 s
->objsize
= max(s
->objsize
, (int)size
);
3057 * And then we need to update the object size in the
3058 * per cpu structures
3060 for_each_online_cpu(cpu
)
3061 get_cpu_slab(s
, cpu
)->objsize
= s
->objsize
;
3062 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3063 up_write(&slub_lock
);
3064 if (sysfs_slab_alias(s
, name
))
3068 s
= kmalloc(kmem_size
, GFP_KERNEL
);
3070 if (kmem_cache_open(s
, GFP_KERNEL
, name
,
3071 size
, align
, flags
, ctor
)) {
3072 list_add(&s
->list
, &slab_caches
);
3073 up_write(&slub_lock
);
3074 if (sysfs_slab_add(s
))
3080 up_write(&slub_lock
);
3083 if (flags
& SLAB_PANIC
)
3084 panic("Cannot create slabcache %s\n", name
);
3089 EXPORT_SYMBOL(kmem_cache_create
);
3093 * Use the cpu notifier to insure that the cpu slabs are flushed when
3096 static int __cpuinit
slab_cpuup_callback(struct notifier_block
*nfb
,
3097 unsigned long action
, void *hcpu
)
3099 long cpu
= (long)hcpu
;
3100 struct kmem_cache
*s
;
3101 unsigned long flags
;
3104 case CPU_UP_PREPARE
:
3105 case CPU_UP_PREPARE_FROZEN
:
3106 init_alloc_cpu_cpu(cpu
);
3107 down_read(&slub_lock
);
3108 list_for_each_entry(s
, &slab_caches
, list
)
3109 s
->cpu_slab
[cpu
] = alloc_kmem_cache_cpu(s
, cpu
,
3111 up_read(&slub_lock
);
3114 case CPU_UP_CANCELED
:
3115 case CPU_UP_CANCELED_FROZEN
:
3117 case CPU_DEAD_FROZEN
:
3118 down_read(&slub_lock
);
3119 list_for_each_entry(s
, &slab_caches
, list
) {
3120 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3122 local_irq_save(flags
);
3123 __flush_cpu_slab(s
, cpu
);
3124 local_irq_restore(flags
);
3125 free_kmem_cache_cpu(c
, cpu
);
3126 s
->cpu_slab
[cpu
] = NULL
;
3128 up_read(&slub_lock
);
3136 static struct notifier_block __cpuinitdata slab_notifier
= {
3137 .notifier_call
= slab_cpuup_callback
3142 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, void *caller
)
3144 struct kmem_cache
*s
;
3146 if (unlikely(size
> PAGE_SIZE
))
3147 return kmalloc_large(size
, gfpflags
);
3149 s
= get_slab(size
, gfpflags
);
3151 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3154 return slab_alloc(s
, gfpflags
, -1, caller
);
3157 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3158 int node
, void *caller
)
3160 struct kmem_cache
*s
;
3162 if (unlikely(size
> PAGE_SIZE
))
3163 return kmalloc_large(size
, gfpflags
);
3165 s
= get_slab(size
, gfpflags
);
3167 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3170 return slab_alloc(s
, gfpflags
, node
, caller
);
3173 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
3174 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3178 void *addr
= page_address(page
);
3180 if (!check_slab(s
, page
) ||
3181 !on_freelist(s
, page
, NULL
))
3184 /* Now we know that a valid freelist exists */
3185 bitmap_zero(map
, s
->objects
);
3187 for_each_free_object(p
, s
, page
->freelist
) {
3188 set_bit(slab_index(p
, s
, addr
), map
);
3189 if (!check_object(s
, page
, p
, 0))
3193 for_each_object(p
, s
, addr
)
3194 if (!test_bit(slab_index(p
, s
, addr
), map
))
3195 if (!check_object(s
, page
, p
, 1))
3200 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
3203 if (slab_trylock(page
)) {
3204 validate_slab(s
, page
, map
);
3207 printk(KERN_INFO
"SLUB %s: Skipped busy slab 0x%p\n",
3210 if (s
->flags
& DEBUG_DEFAULT_FLAGS
) {
3211 if (!SlabDebug(page
))
3212 printk(KERN_ERR
"SLUB %s: SlabDebug not set "
3213 "on slab 0x%p\n", s
->name
, page
);
3215 if (SlabDebug(page
))
3216 printk(KERN_ERR
"SLUB %s: SlabDebug set on "
3217 "slab 0x%p\n", s
->name
, page
);
3221 static int validate_slab_node(struct kmem_cache
*s
,
3222 struct kmem_cache_node
*n
, unsigned long *map
)
3224 unsigned long count
= 0;
3226 unsigned long flags
;
3228 spin_lock_irqsave(&n
->list_lock
, flags
);
3230 list_for_each_entry(page
, &n
->partial
, lru
) {
3231 validate_slab_slab(s
, page
, map
);
3234 if (count
!= n
->nr_partial
)
3235 printk(KERN_ERR
"SLUB %s: %ld partial slabs counted but "
3236 "counter=%ld\n", s
->name
, count
, n
->nr_partial
);
3238 if (!(s
->flags
& SLAB_STORE_USER
))
3241 list_for_each_entry(page
, &n
->full
, lru
) {
3242 validate_slab_slab(s
, page
, map
);
3245 if (count
!= atomic_long_read(&n
->nr_slabs
))
3246 printk(KERN_ERR
"SLUB: %s %ld slabs counted but "
3247 "counter=%ld\n", s
->name
, count
,
3248 atomic_long_read(&n
->nr_slabs
));
3251 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3255 static long validate_slab_cache(struct kmem_cache
*s
)
3258 unsigned long count
= 0;
3259 unsigned long *map
= kmalloc(BITS_TO_LONGS(s
->objects
) *
3260 sizeof(unsigned long), GFP_KERNEL
);
3266 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3267 struct kmem_cache_node
*n
= get_node(s
, node
);
3269 count
+= validate_slab_node(s
, n
, map
);
3275 #ifdef SLUB_RESILIENCY_TEST
3276 static void resiliency_test(void)
3280 printk(KERN_ERR
"SLUB resiliency testing\n");
3281 printk(KERN_ERR
"-----------------------\n");
3282 printk(KERN_ERR
"A. Corruption after allocation\n");
3284 p
= kzalloc(16, GFP_KERNEL
);
3286 printk(KERN_ERR
"\n1. kmalloc-16: Clobber Redzone/next pointer"
3287 " 0x12->0x%p\n\n", p
+ 16);
3289 validate_slab_cache(kmalloc_caches
+ 4);
3291 /* Hmmm... The next two are dangerous */
3292 p
= kzalloc(32, GFP_KERNEL
);
3293 p
[32 + sizeof(void *)] = 0x34;
3294 printk(KERN_ERR
"\n2. kmalloc-32: Clobber next pointer/next slab"
3295 " 0x34 -> -0x%p\n", p
);
3297 "If allocated object is overwritten then not detectable\n\n");
3299 validate_slab_cache(kmalloc_caches
+ 5);
3300 p
= kzalloc(64, GFP_KERNEL
);
3301 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
3303 printk(KERN_ERR
"\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
3306 "If allocated object is overwritten then not detectable\n\n");
3307 validate_slab_cache(kmalloc_caches
+ 6);
3309 printk(KERN_ERR
"\nB. Corruption after free\n");
3310 p
= kzalloc(128, GFP_KERNEL
);
3313 printk(KERN_ERR
"1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
3314 validate_slab_cache(kmalloc_caches
+ 7);
3316 p
= kzalloc(256, GFP_KERNEL
);
3319 printk(KERN_ERR
"\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
3321 validate_slab_cache(kmalloc_caches
+ 8);
3323 p
= kzalloc(512, GFP_KERNEL
);
3326 printk(KERN_ERR
"\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
3327 validate_slab_cache(kmalloc_caches
+ 9);
3330 static void resiliency_test(void) {};
3334 * Generate lists of code addresses where slabcache objects are allocated
3339 unsigned long count
;
3352 unsigned long count
;
3353 struct location
*loc
;
3356 static void free_loc_track(struct loc_track
*t
)
3359 free_pages((unsigned long)t
->loc
,
3360 get_order(sizeof(struct location
) * t
->max
));
3363 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
3368 order
= get_order(sizeof(struct location
) * max
);
3370 l
= (void *)__get_free_pages(flags
, order
);
3375 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
3383 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
3384 const struct track
*track
)
3386 long start
, end
, pos
;
3389 unsigned long age
= jiffies
- track
->when
;
3395 pos
= start
+ (end
- start
+ 1) / 2;
3398 * There is nothing at "end". If we end up there
3399 * we need to add something to before end.
3404 caddr
= t
->loc
[pos
].addr
;
3405 if (track
->addr
== caddr
) {
3411 if (age
< l
->min_time
)
3413 if (age
> l
->max_time
)
3416 if (track
->pid
< l
->min_pid
)
3417 l
->min_pid
= track
->pid
;
3418 if (track
->pid
> l
->max_pid
)
3419 l
->max_pid
= track
->pid
;
3421 cpu_set(track
->cpu
, l
->cpus
);
3423 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3427 if (track
->addr
< caddr
)
3434 * Not found. Insert new tracking element.
3436 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
3442 (t
->count
- pos
) * sizeof(struct location
));
3445 l
->addr
= track
->addr
;
3449 l
->min_pid
= track
->pid
;
3450 l
->max_pid
= track
->pid
;
3451 cpus_clear(l
->cpus
);
3452 cpu_set(track
->cpu
, l
->cpus
);
3453 nodes_clear(l
->nodes
);
3454 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3458 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
3459 struct page
*page
, enum track_item alloc
)
3461 void *addr
= page_address(page
);
3462 DECLARE_BITMAP(map
, s
->objects
);
3465 bitmap_zero(map
, s
->objects
);
3466 for_each_free_object(p
, s
, page
->freelist
)
3467 set_bit(slab_index(p
, s
, addr
), map
);
3469 for_each_object(p
, s
, addr
)
3470 if (!test_bit(slab_index(p
, s
, addr
), map
))
3471 add_location(t
, s
, get_track(s
, p
, alloc
));
3474 static int list_locations(struct kmem_cache
*s
, char *buf
,
3475 enum track_item alloc
)
3479 struct loc_track t
= { 0, 0, NULL
};
3482 if (!alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
3484 return sprintf(buf
, "Out of memory\n");
3486 /* Push back cpu slabs */
3489 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3490 struct kmem_cache_node
*n
= get_node(s
, node
);
3491 unsigned long flags
;
3494 if (!atomic_long_read(&n
->nr_slabs
))
3497 spin_lock_irqsave(&n
->list_lock
, flags
);
3498 list_for_each_entry(page
, &n
->partial
, lru
)
3499 process_slab(&t
, s
, page
, alloc
);
3500 list_for_each_entry(page
, &n
->full
, lru
)
3501 process_slab(&t
, s
, page
, alloc
);
3502 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3505 for (i
= 0; i
< t
.count
; i
++) {
3506 struct location
*l
= &t
.loc
[i
];
3508 if (len
> PAGE_SIZE
- 100)
3510 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
3513 len
+= sprint_symbol(buf
+ len
, (unsigned long)l
->addr
);
3515 len
+= sprintf(buf
+ len
, "<not-available>");
3517 if (l
->sum_time
!= l
->min_time
) {
3518 unsigned long remainder
;
3520 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
3522 div_long_long_rem(l
->sum_time
, l
->count
, &remainder
),
3525 len
+= sprintf(buf
+ len
, " age=%ld",
3528 if (l
->min_pid
!= l
->max_pid
)
3529 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
3530 l
->min_pid
, l
->max_pid
);
3532 len
+= sprintf(buf
+ len
, " pid=%ld",
3535 if (num_online_cpus() > 1 && !cpus_empty(l
->cpus
) &&
3536 len
< PAGE_SIZE
- 60) {
3537 len
+= sprintf(buf
+ len
, " cpus=");
3538 len
+= cpulist_scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
3542 if (num_online_nodes() > 1 && !nodes_empty(l
->nodes
) &&
3543 len
< PAGE_SIZE
- 60) {
3544 len
+= sprintf(buf
+ len
, " nodes=");
3545 len
+= nodelist_scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
3549 len
+= sprintf(buf
+ len
, "\n");
3554 len
+= sprintf(buf
, "No data\n");
3558 enum slab_stat_type
{
3565 #define SO_FULL (1 << SL_FULL)
3566 #define SO_PARTIAL (1 << SL_PARTIAL)
3567 #define SO_CPU (1 << SL_CPU)
3568 #define SO_OBJECTS (1 << SL_OBJECTS)
3570 static unsigned long show_slab_objects(struct kmem_cache
*s
,
3571 char *buf
, unsigned long flags
)
3573 unsigned long total
= 0;
3577 unsigned long *nodes
;
3578 unsigned long *per_cpu
;
3580 nodes
= kzalloc(2 * sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
3581 per_cpu
= nodes
+ nr_node_ids
;
3583 for_each_possible_cpu(cpu
) {
3585 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3595 if (flags
& SO_CPU
) {
3596 if (flags
& SO_OBJECTS
)
3607 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3608 struct kmem_cache_node
*n
= get_node(s
, node
);
3610 if (flags
& SO_PARTIAL
) {
3611 if (flags
& SO_OBJECTS
)
3612 x
= count_partial(n
);
3619 if (flags
& SO_FULL
) {
3620 int full_slabs
= atomic_long_read(&n
->nr_slabs
)
3624 if (flags
& SO_OBJECTS
)
3625 x
= full_slabs
* s
->objects
;
3633 x
= sprintf(buf
, "%lu", total
);
3635 for_each_node_state(node
, N_NORMAL_MEMORY
)
3637 x
+= sprintf(buf
+ x
, " N%d=%lu",
3641 return x
+ sprintf(buf
+ x
, "\n");
3644 static int any_slab_objects(struct kmem_cache
*s
)
3649 for_each_possible_cpu(cpu
) {
3650 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3656 for_each_online_node(node
) {
3657 struct kmem_cache_node
*n
= get_node(s
, node
);
3662 if (n
->nr_partial
|| atomic_long_read(&n
->nr_slabs
))
3668 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3669 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3671 struct slab_attribute
{
3672 struct attribute attr
;
3673 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
3674 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
3677 #define SLAB_ATTR_RO(_name) \
3678 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3680 #define SLAB_ATTR(_name) \
3681 static struct slab_attribute _name##_attr = \
3682 __ATTR(_name, 0644, _name##_show, _name##_store)
3684 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
3686 return sprintf(buf
, "%d\n", s
->size
);
3688 SLAB_ATTR_RO(slab_size
);
3690 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
3692 return sprintf(buf
, "%d\n", s
->align
);
3694 SLAB_ATTR_RO(align
);
3696 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
3698 return sprintf(buf
, "%d\n", s
->objsize
);
3700 SLAB_ATTR_RO(object_size
);
3702 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
3704 return sprintf(buf
, "%d\n", s
->objects
);
3706 SLAB_ATTR_RO(objs_per_slab
);
3708 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
3710 return sprintf(buf
, "%d\n", s
->order
);
3712 SLAB_ATTR_RO(order
);
3714 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
3717 int n
= sprint_symbol(buf
, (unsigned long)s
->ctor
);
3719 return n
+ sprintf(buf
+ n
, "\n");
3725 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
3727 return sprintf(buf
, "%d\n", s
->refcount
- 1);
3729 SLAB_ATTR_RO(aliases
);
3731 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
3733 return show_slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
);
3735 SLAB_ATTR_RO(slabs
);
3737 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
3739 return show_slab_objects(s
, buf
, SO_PARTIAL
);
3741 SLAB_ATTR_RO(partial
);
3743 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
3745 return show_slab_objects(s
, buf
, SO_CPU
);
3747 SLAB_ATTR_RO(cpu_slabs
);
3749 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
3751 return show_slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
|SO_OBJECTS
);
3753 SLAB_ATTR_RO(objects
);
3755 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
3757 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
3760 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
3761 const char *buf
, size_t length
)
3763 s
->flags
&= ~SLAB_DEBUG_FREE
;
3765 s
->flags
|= SLAB_DEBUG_FREE
;
3768 SLAB_ATTR(sanity_checks
);
3770 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
3772 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
3775 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
3778 s
->flags
&= ~SLAB_TRACE
;
3780 s
->flags
|= SLAB_TRACE
;
3785 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
3787 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
3790 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
3791 const char *buf
, size_t length
)
3793 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
3795 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
3798 SLAB_ATTR(reclaim_account
);
3800 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
3802 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
3804 SLAB_ATTR_RO(hwcache_align
);
3806 #ifdef CONFIG_ZONE_DMA
3807 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
3809 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
3811 SLAB_ATTR_RO(cache_dma
);
3814 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
3816 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
3818 SLAB_ATTR_RO(destroy_by_rcu
);
3820 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
3822 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
3825 static ssize_t
red_zone_store(struct kmem_cache
*s
,
3826 const char *buf
, size_t length
)
3828 if (any_slab_objects(s
))
3831 s
->flags
&= ~SLAB_RED_ZONE
;
3833 s
->flags
|= SLAB_RED_ZONE
;
3837 SLAB_ATTR(red_zone
);
3839 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
3841 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
3844 static ssize_t
poison_store(struct kmem_cache
*s
,
3845 const char *buf
, size_t length
)
3847 if (any_slab_objects(s
))
3850 s
->flags
&= ~SLAB_POISON
;
3852 s
->flags
|= SLAB_POISON
;
3858 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
3860 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
3863 static ssize_t
store_user_store(struct kmem_cache
*s
,
3864 const char *buf
, size_t length
)
3866 if (any_slab_objects(s
))
3869 s
->flags
&= ~SLAB_STORE_USER
;
3871 s
->flags
|= SLAB_STORE_USER
;
3875 SLAB_ATTR(store_user
);
3877 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
3882 static ssize_t
validate_store(struct kmem_cache
*s
,
3883 const char *buf
, size_t length
)
3887 if (buf
[0] == '1') {
3888 ret
= validate_slab_cache(s
);
3894 SLAB_ATTR(validate
);
3896 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
3901 static ssize_t
shrink_store(struct kmem_cache
*s
,
3902 const char *buf
, size_t length
)
3904 if (buf
[0] == '1') {
3905 int rc
= kmem_cache_shrink(s
);
3915 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
3917 if (!(s
->flags
& SLAB_STORE_USER
))
3919 return list_locations(s
, buf
, TRACK_ALLOC
);
3921 SLAB_ATTR_RO(alloc_calls
);
3923 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
3925 if (!(s
->flags
& SLAB_STORE_USER
))
3927 return list_locations(s
, buf
, TRACK_FREE
);
3929 SLAB_ATTR_RO(free_calls
);
3932 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
3934 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
3937 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
3938 const char *buf
, size_t length
)
3940 int n
= simple_strtoul(buf
, NULL
, 10);
3943 s
->remote_node_defrag_ratio
= n
* 10;
3946 SLAB_ATTR(remote_node_defrag_ratio
);
3949 #ifdef CONFIG_SLUB_STATS
3951 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
3953 unsigned long sum
= 0;
3956 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
3961 for_each_online_cpu(cpu
) {
3962 unsigned x
= get_cpu_slab(s
, cpu
)->stat
[si
];
3968 len
= sprintf(buf
, "%lu", sum
);
3970 for_each_online_cpu(cpu
) {
3971 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
3972 len
+= sprintf(buf
+ len
, " c%d=%u", cpu
, data
[cpu
]);
3975 return len
+ sprintf(buf
+ len
, "\n");
3978 #define STAT_ATTR(si, text) \
3979 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
3981 return show_stat(s, buf, si); \
3983 SLAB_ATTR_RO(text); \
3985 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
3986 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
3987 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
3988 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
3989 STAT_ATTR(FREE_FROZEN
, free_frozen
);
3990 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
3991 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
3992 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
3993 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
3994 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
3995 STAT_ATTR(FREE_SLAB
, free_slab
);
3996 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
3997 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
3998 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
3999 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4000 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4001 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4005 static struct attribute
*slab_attrs
[] = {
4006 &slab_size_attr
.attr
,
4007 &object_size_attr
.attr
,
4008 &objs_per_slab_attr
.attr
,
4013 &cpu_slabs_attr
.attr
,
4017 &sanity_checks_attr
.attr
,
4019 &hwcache_align_attr
.attr
,
4020 &reclaim_account_attr
.attr
,
4021 &destroy_by_rcu_attr
.attr
,
4022 &red_zone_attr
.attr
,
4024 &store_user_attr
.attr
,
4025 &validate_attr
.attr
,
4027 &alloc_calls_attr
.attr
,
4028 &free_calls_attr
.attr
,
4029 #ifdef CONFIG_ZONE_DMA
4030 &cache_dma_attr
.attr
,
4033 &remote_node_defrag_ratio_attr
.attr
,
4035 #ifdef CONFIG_SLUB_STATS
4036 &alloc_fastpath_attr
.attr
,
4037 &alloc_slowpath_attr
.attr
,
4038 &free_fastpath_attr
.attr
,
4039 &free_slowpath_attr
.attr
,
4040 &free_frozen_attr
.attr
,
4041 &free_add_partial_attr
.attr
,
4042 &free_remove_partial_attr
.attr
,
4043 &alloc_from_partial_attr
.attr
,
4044 &alloc_slab_attr
.attr
,
4045 &alloc_refill_attr
.attr
,
4046 &free_slab_attr
.attr
,
4047 &cpuslab_flush_attr
.attr
,
4048 &deactivate_full_attr
.attr
,
4049 &deactivate_empty_attr
.attr
,
4050 &deactivate_to_head_attr
.attr
,
4051 &deactivate_to_tail_attr
.attr
,
4052 &deactivate_remote_frees_attr
.attr
,
4057 static struct attribute_group slab_attr_group
= {
4058 .attrs
= slab_attrs
,
4061 static ssize_t
slab_attr_show(struct kobject
*kobj
,
4062 struct attribute
*attr
,
4065 struct slab_attribute
*attribute
;
4066 struct kmem_cache
*s
;
4069 attribute
= to_slab_attr(attr
);
4072 if (!attribute
->show
)
4075 err
= attribute
->show(s
, buf
);
4080 static ssize_t
slab_attr_store(struct kobject
*kobj
,
4081 struct attribute
*attr
,
4082 const char *buf
, size_t len
)
4084 struct slab_attribute
*attribute
;
4085 struct kmem_cache
*s
;
4088 attribute
= to_slab_attr(attr
);
4091 if (!attribute
->store
)
4094 err
= attribute
->store(s
, buf
, len
);
4099 static void kmem_cache_release(struct kobject
*kobj
)
4101 struct kmem_cache
*s
= to_slab(kobj
);
4106 static struct sysfs_ops slab_sysfs_ops
= {
4107 .show
= slab_attr_show
,
4108 .store
= slab_attr_store
,
4111 static struct kobj_type slab_ktype
= {
4112 .sysfs_ops
= &slab_sysfs_ops
,
4113 .release
= kmem_cache_release
4116 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
4118 struct kobj_type
*ktype
= get_ktype(kobj
);
4120 if (ktype
== &slab_ktype
)
4125 static struct kset_uevent_ops slab_uevent_ops
= {
4126 .filter
= uevent_filter
,
4129 static struct kset
*slab_kset
;
4131 #define ID_STR_LENGTH 64
4133 /* Create a unique string id for a slab cache:
4135 * :[flags-]size:[memory address of kmemcache]
4137 static char *create_unique_id(struct kmem_cache
*s
)
4139 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
4146 * First flags affecting slabcache operations. We will only
4147 * get here for aliasable slabs so we do not need to support
4148 * too many flags. The flags here must cover all flags that
4149 * are matched during merging to guarantee that the id is
4152 if (s
->flags
& SLAB_CACHE_DMA
)
4154 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
4156 if (s
->flags
& SLAB_DEBUG_FREE
)
4160 p
+= sprintf(p
, "%07d", s
->size
);
4161 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
4165 static int sysfs_slab_add(struct kmem_cache
*s
)
4171 if (slab_state
< SYSFS
)
4172 /* Defer until later */
4175 unmergeable
= slab_unmergeable(s
);
4178 * Slabcache can never be merged so we can use the name proper.
4179 * This is typically the case for debug situations. In that
4180 * case we can catch duplicate names easily.
4182 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
4186 * Create a unique name for the slab as a target
4189 name
= create_unique_id(s
);
4192 s
->kobj
.kset
= slab_kset
;
4193 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, name
);
4195 kobject_put(&s
->kobj
);
4199 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
4202 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
4204 /* Setup first alias */
4205 sysfs_slab_alias(s
, s
->name
);
4211 static void sysfs_slab_remove(struct kmem_cache
*s
)
4213 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
4214 kobject_del(&s
->kobj
);
4215 kobject_put(&s
->kobj
);
4219 * Need to buffer aliases during bootup until sysfs becomes
4220 * available lest we loose that information.
4222 struct saved_alias
{
4223 struct kmem_cache
*s
;
4225 struct saved_alias
*next
;
4228 static struct saved_alias
*alias_list
;
4230 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
4232 struct saved_alias
*al
;
4234 if (slab_state
== SYSFS
) {
4236 * If we have a leftover link then remove it.
4238 sysfs_remove_link(&slab_kset
->kobj
, name
);
4239 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
4242 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
4248 al
->next
= alias_list
;
4253 static int __init
slab_sysfs_init(void)
4255 struct kmem_cache
*s
;
4258 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
4260 printk(KERN_ERR
"Cannot register slab subsystem.\n");
4266 list_for_each_entry(s
, &slab_caches
, list
) {
4267 err
= sysfs_slab_add(s
);
4269 printk(KERN_ERR
"SLUB: Unable to add boot slab %s"
4270 " to sysfs\n", s
->name
);
4273 while (alias_list
) {
4274 struct saved_alias
*al
= alias_list
;
4276 alias_list
= alias_list
->next
;
4277 err
= sysfs_slab_alias(al
->s
, al
->name
);
4279 printk(KERN_ERR
"SLUB: Unable to add boot slab alias"
4280 " %s to sysfs\n", s
->name
);
4288 __initcall(slab_sysfs_init
);
4292 * The /proc/slabinfo ABI
4294 #ifdef CONFIG_SLABINFO
4296 ssize_t
slabinfo_write(struct file
*file
, const char __user
* buffer
,
4297 size_t count
, loff_t
*ppos
)
4303 static void print_slabinfo_header(struct seq_file
*m
)
4305 seq_puts(m
, "slabinfo - version: 2.1\n");
4306 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
4307 "<objperslab> <pagesperslab>");
4308 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
4309 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4313 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
4317 down_read(&slub_lock
);
4319 print_slabinfo_header(m
);
4321 return seq_list_start(&slab_caches
, *pos
);
4324 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
4326 return seq_list_next(p
, &slab_caches
, pos
);
4329 static void s_stop(struct seq_file
*m
, void *p
)
4331 up_read(&slub_lock
);
4334 static int s_show(struct seq_file
*m
, void *p
)
4336 unsigned long nr_partials
= 0;
4337 unsigned long nr_slabs
= 0;
4338 unsigned long nr_inuse
= 0;
4339 unsigned long nr_objs
;
4340 struct kmem_cache
*s
;
4343 s
= list_entry(p
, struct kmem_cache
, list
);
4345 for_each_online_node(node
) {
4346 struct kmem_cache_node
*n
= get_node(s
, node
);
4351 nr_partials
+= n
->nr_partial
;
4352 nr_slabs
+= atomic_long_read(&n
->nr_slabs
);
4353 nr_inuse
+= count_partial(n
);
4356 nr_objs
= nr_slabs
* s
->objects
;
4357 nr_inuse
+= (nr_slabs
- nr_partials
) * s
->objects
;
4359 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d", s
->name
, nr_inuse
,
4360 nr_objs
, s
->size
, s
->objects
, (1 << s
->order
));
4361 seq_printf(m
, " : tunables %4u %4u %4u", 0, 0, 0);
4362 seq_printf(m
, " : slabdata %6lu %6lu %6lu", nr_slabs
, nr_slabs
,
4368 const struct seq_operations slabinfo_op
= {
4375 #endif /* CONFIG_SLABINFO */