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 /* Verify that a pointer has an address that is valid within a slab page */
295 static inline int check_valid_pointer(struct kmem_cache
*s
,
296 struct page
*page
, const void *object
)
303 base
= page_address(page
);
304 if (object
< base
|| object
>= base
+ page
->objects
* s
->size
||
305 (object
- base
) % s
->size
) {
313 * Slow version of get and set free pointer.
315 * This version requires touching the cache lines of kmem_cache which
316 * we avoid to do in the fast alloc free paths. There we obtain the offset
317 * from the page struct.
319 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
321 return *(void **)(object
+ s
->offset
);
324 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
326 *(void **)(object
+ s
->offset
) = fp
;
329 /* Loop over all objects in a slab */
330 #define for_each_object(__p, __s, __addr, __objects) \
331 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
335 #define for_each_free_object(__p, __s, __free) \
336 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
338 /* Determine object index from a given position */
339 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
341 return (p
- addr
) / s
->size
;
344 static inline struct kmem_cache_order_objects
oo_make(int order
,
347 struct kmem_cache_order_objects x
= {
348 (order
<< 16) + (PAGE_SIZE
<< order
) / size
354 static inline int oo_order(struct kmem_cache_order_objects x
)
359 static inline int oo_objects(struct kmem_cache_order_objects x
)
361 return x
.x
& ((1 << 16) - 1);
364 #ifdef CONFIG_SLUB_DEBUG
368 #ifdef CONFIG_SLUB_DEBUG_ON
369 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
371 static int slub_debug
;
374 static char *slub_debug_slabs
;
379 static void print_section(char *text
, u8
*addr
, unsigned int length
)
387 for (i
= 0; i
< length
; i
++) {
389 printk(KERN_ERR
"%8s 0x%p: ", text
, addr
+ i
);
392 printk(KERN_CONT
" %02x", addr
[i
]);
394 ascii
[offset
] = isgraph(addr
[i
]) ? addr
[i
] : '.';
396 printk(KERN_CONT
" %s\n", ascii
);
403 printk(KERN_CONT
" ");
407 printk(KERN_CONT
" %s\n", ascii
);
411 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
412 enum track_item alloc
)
417 p
= object
+ s
->offset
+ sizeof(void *);
419 p
= object
+ s
->inuse
;
424 static void set_track(struct kmem_cache
*s
, void *object
,
425 enum track_item alloc
, void *addr
)
430 p
= object
+ s
->offset
+ sizeof(void *);
432 p
= object
+ s
->inuse
;
437 p
->cpu
= smp_processor_id();
438 p
->pid
= current
? current
->pid
: -1;
441 memset(p
, 0, sizeof(struct track
));
444 static void init_tracking(struct kmem_cache
*s
, void *object
)
446 if (!(s
->flags
& SLAB_STORE_USER
))
449 set_track(s
, object
, TRACK_FREE
, NULL
);
450 set_track(s
, object
, TRACK_ALLOC
, NULL
);
453 static void print_track(const char *s
, struct track
*t
)
458 printk(KERN_ERR
"INFO: %s in ", s
);
459 __print_symbol("%s", (unsigned long)t
->addr
);
460 printk(" age=%lu cpu=%u pid=%d\n", jiffies
- t
->when
, t
->cpu
, t
->pid
);
463 static void print_tracking(struct kmem_cache
*s
, void *object
)
465 if (!(s
->flags
& SLAB_STORE_USER
))
468 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
469 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
472 static void print_page_info(struct page
*page
)
474 printk(KERN_ERR
"INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
475 page
, page
->objects
, page
->inuse
, page
->freelist
, page
->flags
);
479 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
485 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
487 printk(KERN_ERR
"========================================"
488 "=====================================\n");
489 printk(KERN_ERR
"BUG %s: %s\n", s
->name
, buf
);
490 printk(KERN_ERR
"----------------------------------------"
491 "-------------------------------------\n\n");
494 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
500 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
502 printk(KERN_ERR
"FIX %s: %s\n", s
->name
, buf
);
505 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
507 unsigned int off
; /* Offset of last byte */
508 u8
*addr
= page_address(page
);
510 print_tracking(s
, p
);
512 print_page_info(page
);
514 printk(KERN_ERR
"INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
515 p
, p
- addr
, get_freepointer(s
, p
));
518 print_section("Bytes b4", p
- 16, 16);
520 print_section("Object", p
, min(s
->objsize
, 128));
522 if (s
->flags
& SLAB_RED_ZONE
)
523 print_section("Redzone", p
+ s
->objsize
,
524 s
->inuse
- s
->objsize
);
527 off
= s
->offset
+ sizeof(void *);
531 if (s
->flags
& SLAB_STORE_USER
)
532 off
+= 2 * sizeof(struct track
);
535 /* Beginning of the filler is the free pointer */
536 print_section("Padding", p
+ off
, s
->size
- off
);
541 static void object_err(struct kmem_cache
*s
, struct page
*page
,
542 u8
*object
, char *reason
)
544 slab_bug(s
, "%s", reason
);
545 print_trailer(s
, page
, object
);
548 static void slab_err(struct kmem_cache
*s
, struct page
*page
, char *fmt
, ...)
554 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
556 slab_bug(s
, "%s", buf
);
557 print_page_info(page
);
561 static void init_object(struct kmem_cache
*s
, void *object
, int active
)
565 if (s
->flags
& __OBJECT_POISON
) {
566 memset(p
, POISON_FREE
, s
->objsize
- 1);
567 p
[s
->objsize
- 1] = POISON_END
;
570 if (s
->flags
& SLAB_RED_ZONE
)
571 memset(p
+ s
->objsize
,
572 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
,
573 s
->inuse
- s
->objsize
);
576 static u8
*check_bytes(u8
*start
, unsigned int value
, unsigned int bytes
)
579 if (*start
!= (u8
)value
)
587 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
588 void *from
, void *to
)
590 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
591 memset(from
, data
, to
- from
);
594 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
595 u8
*object
, char *what
,
596 u8
*start
, unsigned int value
, unsigned int bytes
)
601 fault
= check_bytes(start
, value
, bytes
);
606 while (end
> fault
&& end
[-1] == value
)
609 slab_bug(s
, "%s overwritten", what
);
610 printk(KERN_ERR
"INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
611 fault
, end
- 1, fault
[0], value
);
612 print_trailer(s
, page
, object
);
614 restore_bytes(s
, what
, value
, fault
, end
);
622 * Bytes of the object to be managed.
623 * If the freepointer may overlay the object then the free
624 * pointer is the first word of the object.
626 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
629 * object + s->objsize
630 * Padding to reach word boundary. This is also used for Redzoning.
631 * Padding is extended by another word if Redzoning is enabled and
634 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
635 * 0xcc (RED_ACTIVE) for objects in use.
638 * Meta data starts here.
640 * A. Free pointer (if we cannot overwrite object on free)
641 * B. Tracking data for SLAB_STORE_USER
642 * C. Padding to reach required alignment boundary or at mininum
643 * one word if debugging is on to be able to detect writes
644 * before the word boundary.
646 * Padding is done using 0x5a (POISON_INUSE)
649 * Nothing is used beyond s->size.
651 * If slabcaches are merged then the objsize and inuse boundaries are mostly
652 * ignored. And therefore no slab options that rely on these boundaries
653 * may be used with merged slabcaches.
656 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
658 unsigned long off
= s
->inuse
; /* The end of info */
661 /* Freepointer is placed after the object. */
662 off
+= sizeof(void *);
664 if (s
->flags
& SLAB_STORE_USER
)
665 /* We also have user information there */
666 off
+= 2 * sizeof(struct track
);
671 return check_bytes_and_report(s
, page
, p
, "Object padding",
672 p
+ off
, POISON_INUSE
, s
->size
- off
);
675 /* Check the pad bytes at the end of a slab page */
676 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
684 if (!(s
->flags
& SLAB_POISON
))
687 start
= page_address(page
);
688 length
= (PAGE_SIZE
<< compound_order(page
));
689 end
= start
+ length
;
690 remainder
= length
% s
->size
;
694 fault
= check_bytes(end
- remainder
, POISON_INUSE
, remainder
);
697 while (end
> fault
&& end
[-1] == POISON_INUSE
)
700 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
701 print_section("Padding", end
- remainder
, remainder
);
703 restore_bytes(s
, "slab padding", POISON_INUSE
, start
, end
);
707 static int check_object(struct kmem_cache
*s
, struct page
*page
,
708 void *object
, int active
)
711 u8
*endobject
= object
+ s
->objsize
;
713 if (s
->flags
& SLAB_RED_ZONE
) {
715 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
;
717 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
718 endobject
, red
, s
->inuse
- s
->objsize
))
721 if ((s
->flags
& SLAB_POISON
) && s
->objsize
< s
->inuse
) {
722 check_bytes_and_report(s
, page
, p
, "Alignment padding",
723 endobject
, POISON_INUSE
, s
->inuse
- s
->objsize
);
727 if (s
->flags
& SLAB_POISON
) {
728 if (!active
&& (s
->flags
& __OBJECT_POISON
) &&
729 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
730 POISON_FREE
, s
->objsize
- 1) ||
731 !check_bytes_and_report(s
, page
, p
, "Poison",
732 p
+ s
->objsize
- 1, POISON_END
, 1)))
735 * check_pad_bytes cleans up on its own.
737 check_pad_bytes(s
, page
, p
);
740 if (!s
->offset
&& active
)
742 * Object and freepointer overlap. Cannot check
743 * freepointer while object is allocated.
747 /* Check free pointer validity */
748 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
749 object_err(s
, page
, p
, "Freepointer corrupt");
751 * No choice but to zap it and thus loose the remainder
752 * of the free objects in this slab. May cause
753 * another error because the object count is now wrong.
755 set_freepointer(s
, p
, NULL
);
761 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
765 VM_BUG_ON(!irqs_disabled());
767 if (!PageSlab(page
)) {
768 slab_err(s
, page
, "Not a valid slab page");
772 maxobj
= (PAGE_SIZE
<< compound_order(page
)) / s
->size
;
773 if (page
->objects
> maxobj
) {
774 slab_err(s
, page
, "objects %u > max %u",
775 s
->name
, page
->objects
, maxobj
);
778 if (page
->inuse
> page
->objects
) {
779 slab_err(s
, page
, "inuse %u > max %u",
780 s
->name
, page
->inuse
, page
->objects
);
783 /* Slab_pad_check fixes things up after itself */
784 slab_pad_check(s
, page
);
789 * Determine if a certain object on a page is on the freelist. Must hold the
790 * slab lock to guarantee that the chains are in a consistent state.
792 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
795 void *fp
= page
->freelist
;
797 unsigned long max_objects
;
799 while (fp
&& nr
<= page
->objects
) {
802 if (!check_valid_pointer(s
, page
, fp
)) {
804 object_err(s
, page
, object
,
805 "Freechain corrupt");
806 set_freepointer(s
, object
, NULL
);
809 slab_err(s
, page
, "Freepointer corrupt");
810 page
->freelist
= NULL
;
811 page
->inuse
= page
->objects
;
812 slab_fix(s
, "Freelist cleared");
818 fp
= get_freepointer(s
, object
);
822 max_objects
= (PAGE_SIZE
<< compound_order(page
)) / s
->size
;
823 if (max_objects
> 65535)
826 if (page
->objects
!= max_objects
) {
827 slab_err(s
, page
, "Wrong number of objects. Found %d but "
828 "should be %d", page
->objects
, max_objects
);
829 page
->objects
= max_objects
;
830 slab_fix(s
, "Number of objects adjusted.");
832 if (page
->inuse
!= page
->objects
- nr
) {
833 slab_err(s
, page
, "Wrong object count. Counter is %d but "
834 "counted were %d", page
->inuse
, page
->objects
- nr
);
835 page
->inuse
= page
->objects
- nr
;
836 slab_fix(s
, "Object count adjusted.");
838 return search
== NULL
;
841 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
, int alloc
)
843 if (s
->flags
& SLAB_TRACE
) {
844 printk(KERN_INFO
"TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
846 alloc
? "alloc" : "free",
851 print_section("Object", (void *)object
, s
->objsize
);
858 * Tracking of fully allocated slabs for debugging purposes.
860 static void add_full(struct kmem_cache_node
*n
, struct page
*page
)
862 spin_lock(&n
->list_lock
);
863 list_add(&page
->lru
, &n
->full
);
864 spin_unlock(&n
->list_lock
);
867 static void remove_full(struct kmem_cache
*s
, struct page
*page
)
869 struct kmem_cache_node
*n
;
871 if (!(s
->flags
& SLAB_STORE_USER
))
874 n
= get_node(s
, page_to_nid(page
));
876 spin_lock(&n
->list_lock
);
877 list_del(&page
->lru
);
878 spin_unlock(&n
->list_lock
);
881 /* Tracking of the number of slabs for debugging purposes */
882 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
884 struct kmem_cache_node
*n
= get_node(s
, node
);
886 return atomic_long_read(&n
->nr_slabs
);
889 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
)
891 struct kmem_cache_node
*n
= get_node(s
, node
);
894 * May be called early in order to allocate a slab for the
895 * kmem_cache_node structure. Solve the chicken-egg
896 * dilemma by deferring the increment of the count during
897 * bootstrap (see early_kmem_cache_node_alloc).
899 if (!NUMA_BUILD
|| n
)
900 atomic_long_inc(&n
->nr_slabs
);
902 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
)
904 struct kmem_cache_node
*n
= get_node(s
, node
);
906 atomic_long_dec(&n
->nr_slabs
);
909 /* Object debug checks for alloc/free paths */
910 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
913 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
916 init_object(s
, object
, 0);
917 init_tracking(s
, object
);
920 static int alloc_debug_processing(struct kmem_cache
*s
, struct page
*page
,
921 void *object
, void *addr
)
923 if (!check_slab(s
, page
))
926 if (!on_freelist(s
, page
, object
)) {
927 object_err(s
, page
, object
, "Object already allocated");
931 if (!check_valid_pointer(s
, page
, object
)) {
932 object_err(s
, page
, object
, "Freelist Pointer check fails");
936 if (!check_object(s
, page
, object
, 0))
939 /* Success perform special debug activities for allocs */
940 if (s
->flags
& SLAB_STORE_USER
)
941 set_track(s
, object
, TRACK_ALLOC
, addr
);
942 trace(s
, page
, object
, 1);
943 init_object(s
, object
, 1);
947 if (PageSlab(page
)) {
949 * If this is a slab page then lets do the best we can
950 * to avoid issues in the future. Marking all objects
951 * as used avoids touching the remaining objects.
953 slab_fix(s
, "Marking all objects used");
954 page
->inuse
= page
->objects
;
955 page
->freelist
= NULL
;
960 static int free_debug_processing(struct kmem_cache
*s
, struct page
*page
,
961 void *object
, void *addr
)
963 if (!check_slab(s
, page
))
966 if (!check_valid_pointer(s
, page
, object
)) {
967 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
971 if (on_freelist(s
, page
, object
)) {
972 object_err(s
, page
, object
, "Object already free");
976 if (!check_object(s
, page
, object
, 1))
979 if (unlikely(s
!= page
->slab
)) {
980 if (!PageSlab(page
)) {
981 slab_err(s
, page
, "Attempt to free object(0x%p) "
982 "outside of slab", object
);
983 } else if (!page
->slab
) {
985 "SLUB <none>: no slab for object 0x%p.\n",
989 object_err(s
, page
, object
,
990 "page slab pointer corrupt.");
994 /* Special debug activities for freeing objects */
995 if (!SlabFrozen(page
) && !page
->freelist
)
996 remove_full(s
, page
);
997 if (s
->flags
& SLAB_STORE_USER
)
998 set_track(s
, object
, TRACK_FREE
, addr
);
999 trace(s
, page
, object
, 0);
1000 init_object(s
, object
, 0);
1004 slab_fix(s
, "Object at 0x%p not freed", object
);
1008 static int __init
setup_slub_debug(char *str
)
1010 slub_debug
= DEBUG_DEFAULT_FLAGS
;
1011 if (*str
++ != '=' || !*str
)
1013 * No options specified. Switch on full debugging.
1019 * No options but restriction on slabs. This means full
1020 * debugging for slabs matching a pattern.
1027 * Switch off all debugging measures.
1032 * Determine which debug features should be switched on
1034 for (; *str
&& *str
!= ','; str
++) {
1035 switch (tolower(*str
)) {
1037 slub_debug
|= SLAB_DEBUG_FREE
;
1040 slub_debug
|= SLAB_RED_ZONE
;
1043 slub_debug
|= SLAB_POISON
;
1046 slub_debug
|= SLAB_STORE_USER
;
1049 slub_debug
|= SLAB_TRACE
;
1052 printk(KERN_ERR
"slub_debug option '%c' "
1053 "unknown. skipped\n", *str
);
1059 slub_debug_slabs
= str
+ 1;
1064 __setup("slub_debug", setup_slub_debug
);
1066 static unsigned long kmem_cache_flags(unsigned long objsize
,
1067 unsigned long flags
, const char *name
,
1068 void (*ctor
)(struct kmem_cache
*, void *))
1071 * Enable debugging if selected on the kernel commandline.
1073 if (slub_debug
&& (!slub_debug_slabs
||
1074 strncmp(slub_debug_slabs
, name
, strlen(slub_debug_slabs
)) == 0))
1075 flags
|= slub_debug
;
1080 static inline void setup_object_debug(struct kmem_cache
*s
,
1081 struct page
*page
, void *object
) {}
1083 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1084 struct page
*page
, void *object
, void *addr
) { return 0; }
1086 static inline int free_debug_processing(struct kmem_cache
*s
,
1087 struct page
*page
, void *object
, void *addr
) { return 0; }
1089 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1091 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1092 void *object
, int active
) { return 1; }
1093 static inline void add_full(struct kmem_cache_node
*n
, struct page
*page
) {}
1094 static inline unsigned long kmem_cache_flags(unsigned long objsize
,
1095 unsigned long flags
, const char *name
,
1096 void (*ctor
)(struct kmem_cache
*, void *))
1100 #define slub_debug 0
1102 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1104 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
) {}
1105 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
) {}
1108 * Slab allocation and freeing
1110 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1113 struct kmem_cache_order_objects oo
= s
->oo
;
1114 int order
= oo_order(oo
);
1115 int pages
= 1 << order
;
1117 flags
|= s
->allocflags
;
1120 page
= alloc_pages(flags
, order
);
1122 page
= alloc_pages_node(node
, flags
, order
);
1127 page
->objects
= oo_objects(oo
);
1128 mod_zone_page_state(page_zone(page
),
1129 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1130 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1136 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1139 setup_object_debug(s
, page
, object
);
1140 if (unlikely(s
->ctor
))
1144 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1151 BUG_ON(flags
& GFP_SLAB_BUG_MASK
);
1153 page
= allocate_slab(s
,
1154 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1158 inc_slabs_node(s
, page_to_nid(page
));
1160 page
->flags
|= 1 << PG_slab
;
1161 if (s
->flags
& (SLAB_DEBUG_FREE
| SLAB_RED_ZONE
| SLAB_POISON
|
1162 SLAB_STORE_USER
| SLAB_TRACE
))
1165 start
= page_address(page
);
1167 if (unlikely(s
->flags
& SLAB_POISON
))
1168 memset(start
, POISON_INUSE
, PAGE_SIZE
<< compound_order(page
));
1171 for_each_object(p
, s
, start
, page
->objects
) {
1172 setup_object(s
, page
, last
);
1173 set_freepointer(s
, last
, p
);
1176 setup_object(s
, page
, last
);
1177 set_freepointer(s
, last
, NULL
);
1179 page
->freelist
= start
;
1185 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1187 int order
= compound_order(page
);
1188 int pages
= 1 << order
;
1190 if (unlikely(SlabDebug(page
))) {
1193 slab_pad_check(s
, page
);
1194 for_each_object(p
, s
, page_address(page
),
1196 check_object(s
, page
, p
, 0);
1197 ClearSlabDebug(page
);
1200 mod_zone_page_state(page_zone(page
),
1201 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1202 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1205 __ClearPageSlab(page
);
1206 reset_page_mapcount(page
);
1207 __free_pages(page
, order
);
1210 static void rcu_free_slab(struct rcu_head
*h
)
1214 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1215 __free_slab(page
->slab
, page
);
1218 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1220 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1222 * RCU free overloads the RCU head over the LRU
1224 struct rcu_head
*head
= (void *)&page
->lru
;
1226 call_rcu(head
, rcu_free_slab
);
1228 __free_slab(s
, page
);
1231 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1233 dec_slabs_node(s
, page_to_nid(page
));
1238 * Per slab locking using the pagelock
1240 static __always_inline
void slab_lock(struct page
*page
)
1242 bit_spin_lock(PG_locked
, &page
->flags
);
1245 static __always_inline
void slab_unlock(struct page
*page
)
1247 __bit_spin_unlock(PG_locked
, &page
->flags
);
1250 static __always_inline
int slab_trylock(struct page
*page
)
1254 rc
= bit_spin_trylock(PG_locked
, &page
->flags
);
1259 * Management of partially allocated slabs
1261 static void add_partial(struct kmem_cache_node
*n
,
1262 struct page
*page
, int tail
)
1264 spin_lock(&n
->list_lock
);
1267 list_add_tail(&page
->lru
, &n
->partial
);
1269 list_add(&page
->lru
, &n
->partial
);
1270 spin_unlock(&n
->list_lock
);
1273 static void remove_partial(struct kmem_cache
*s
,
1276 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1278 spin_lock(&n
->list_lock
);
1279 list_del(&page
->lru
);
1281 spin_unlock(&n
->list_lock
);
1285 * Lock slab and remove from the partial list.
1287 * Must hold list_lock.
1289 static inline int lock_and_freeze_slab(struct kmem_cache_node
*n
, struct page
*page
)
1291 if (slab_trylock(page
)) {
1292 list_del(&page
->lru
);
1294 SetSlabFrozen(page
);
1301 * Try to allocate a partial slab from a specific node.
1303 static struct page
*get_partial_node(struct kmem_cache_node
*n
)
1308 * Racy check. If we mistakenly see no partial slabs then we
1309 * just allocate an empty slab. If we mistakenly try to get a
1310 * partial slab and there is none available then get_partials()
1313 if (!n
|| !n
->nr_partial
)
1316 spin_lock(&n
->list_lock
);
1317 list_for_each_entry(page
, &n
->partial
, lru
)
1318 if (lock_and_freeze_slab(n
, page
))
1322 spin_unlock(&n
->list_lock
);
1327 * Get a page from somewhere. Search in increasing NUMA distances.
1329 static struct page
*get_any_partial(struct kmem_cache
*s
, gfp_t flags
)
1332 struct zonelist
*zonelist
;
1337 * The defrag ratio allows a configuration of the tradeoffs between
1338 * inter node defragmentation and node local allocations. A lower
1339 * defrag_ratio increases the tendency to do local allocations
1340 * instead of attempting to obtain partial slabs from other nodes.
1342 * If the defrag_ratio is set to 0 then kmalloc() always
1343 * returns node local objects. If the ratio is higher then kmalloc()
1344 * may return off node objects because partial slabs are obtained
1345 * from other nodes and filled up.
1347 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1348 * defrag_ratio = 1000) then every (well almost) allocation will
1349 * first attempt to defrag slab caches on other nodes. This means
1350 * scanning over all nodes to look for partial slabs which may be
1351 * expensive if we do it every time we are trying to find a slab
1352 * with available objects.
1354 if (!s
->remote_node_defrag_ratio
||
1355 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1358 zonelist
= &NODE_DATA(
1359 slab_node(current
->mempolicy
))->node_zonelists
[gfp_zone(flags
)];
1360 for (z
= zonelist
->zones
; *z
; z
++) {
1361 struct kmem_cache_node
*n
;
1363 n
= get_node(s
, zone_to_nid(*z
));
1365 if (n
&& cpuset_zone_allowed_hardwall(*z
, flags
) &&
1366 n
->nr_partial
> MIN_PARTIAL
) {
1367 page
= get_partial_node(n
);
1377 * Get a partial page, lock it and return it.
1379 static struct page
*get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
)
1382 int searchnode
= (node
== -1) ? numa_node_id() : node
;
1384 page
= get_partial_node(get_node(s
, searchnode
));
1385 if (page
|| (flags
& __GFP_THISNODE
))
1388 return get_any_partial(s
, flags
);
1392 * Move a page back to the lists.
1394 * Must be called with the slab lock held.
1396 * On exit the slab lock will have been dropped.
1398 static void unfreeze_slab(struct kmem_cache
*s
, struct page
*page
, int tail
)
1400 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1401 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, smp_processor_id());
1403 ClearSlabFrozen(page
);
1406 if (page
->freelist
) {
1407 add_partial(n
, page
, tail
);
1408 stat(c
, tail
? DEACTIVATE_TO_TAIL
: DEACTIVATE_TO_HEAD
);
1410 stat(c
, DEACTIVATE_FULL
);
1411 if (SlabDebug(page
) && (s
->flags
& SLAB_STORE_USER
))
1416 stat(c
, DEACTIVATE_EMPTY
);
1417 if (n
->nr_partial
< MIN_PARTIAL
) {
1419 * Adding an empty slab to the partial slabs in order
1420 * to avoid page allocator overhead. This slab needs
1421 * to come after the other slabs with objects in
1422 * so that the others get filled first. That way the
1423 * size of the partial list stays small.
1425 * kmem_cache_shrink can reclaim any empty slabs from the
1428 add_partial(n
, page
, 1);
1432 stat(get_cpu_slab(s
, raw_smp_processor_id()), FREE_SLAB
);
1433 discard_slab(s
, page
);
1439 * Remove the cpu slab
1441 static void deactivate_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1443 struct page
*page
= c
->page
;
1447 stat(c
, DEACTIVATE_REMOTE_FREES
);
1449 * Merge cpu freelist into slab freelist. Typically we get here
1450 * because both freelists are empty. So this is unlikely
1453 while (unlikely(c
->freelist
)) {
1456 tail
= 0; /* Hot objects. Put the slab first */
1458 /* Retrieve object from cpu_freelist */
1459 object
= c
->freelist
;
1460 c
->freelist
= c
->freelist
[c
->offset
];
1462 /* And put onto the regular freelist */
1463 object
[c
->offset
] = page
->freelist
;
1464 page
->freelist
= object
;
1468 unfreeze_slab(s
, page
, tail
);
1471 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1473 stat(c
, CPUSLAB_FLUSH
);
1475 deactivate_slab(s
, c
);
1481 * Called from IPI handler with interrupts disabled.
1483 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
1485 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
1487 if (likely(c
&& c
->page
))
1491 static void flush_cpu_slab(void *d
)
1493 struct kmem_cache
*s
= d
;
1495 __flush_cpu_slab(s
, smp_processor_id());
1498 static void flush_all(struct kmem_cache
*s
)
1501 on_each_cpu(flush_cpu_slab
, s
, 1, 1);
1503 unsigned long flags
;
1505 local_irq_save(flags
);
1507 local_irq_restore(flags
);
1512 * Check if the objects in a per cpu structure fit numa
1513 * locality expectations.
1515 static inline int node_match(struct kmem_cache_cpu
*c
, int node
)
1518 if (node
!= -1 && c
->node
!= node
)
1525 * Slow path. The lockless freelist is empty or we need to perform
1528 * Interrupts are disabled.
1530 * Processing is still very fast if new objects have been freed to the
1531 * regular freelist. In that case we simply take over the regular freelist
1532 * as the lockless freelist and zap the regular freelist.
1534 * If that is not working then we fall back to the partial lists. We take the
1535 * first element of the freelist as the object to allocate now and move the
1536 * rest of the freelist to the lockless freelist.
1538 * And if we were unable to get a new slab from the partial slab lists then
1539 * we need to allocate a new slab. This is the slowest path since it involves
1540 * a call to the page allocator and the setup of a new slab.
1542 static void *__slab_alloc(struct kmem_cache
*s
,
1543 gfp_t gfpflags
, int node
, void *addr
, struct kmem_cache_cpu
*c
)
1548 /* We handle __GFP_ZERO in the caller */
1549 gfpflags
&= ~__GFP_ZERO
;
1555 if (unlikely(!node_match(c
, node
)))
1558 stat(c
, ALLOC_REFILL
);
1561 object
= c
->page
->freelist
;
1562 if (unlikely(!object
))
1564 if (unlikely(SlabDebug(c
->page
)))
1567 c
->freelist
= object
[c
->offset
];
1568 c
->page
->inuse
= c
->page
->objects
;
1569 c
->page
->freelist
= NULL
;
1570 c
->node
= page_to_nid(c
->page
);
1572 slab_unlock(c
->page
);
1573 stat(c
, ALLOC_SLOWPATH
);
1577 deactivate_slab(s
, c
);
1580 new = get_partial(s
, gfpflags
, node
);
1583 stat(c
, ALLOC_FROM_PARTIAL
);
1587 if (gfpflags
& __GFP_WAIT
)
1590 new = new_slab(s
, gfpflags
, node
);
1592 if (gfpflags
& __GFP_WAIT
)
1593 local_irq_disable();
1596 c
= get_cpu_slab(s
, smp_processor_id());
1597 stat(c
, ALLOC_SLAB
);
1607 * No memory available.
1609 * If the slab uses higher order allocs but the object is
1610 * smaller than a page size then we can fallback in emergencies
1611 * to the page allocator via kmalloc_large. The page allocator may
1612 * have failed to obtain a higher order page and we can try to
1613 * allocate a single page if the object fits into a single page.
1614 * That is only possible if certain conditions are met that are being
1615 * checked when a slab is created.
1617 if (!(gfpflags
& __GFP_NORETRY
) &&
1618 (s
->flags
& __PAGE_ALLOC_FALLBACK
)) {
1619 if (gfpflags
& __GFP_WAIT
)
1621 object
= kmalloc_large(s
->objsize
, gfpflags
);
1622 if (gfpflags
& __GFP_WAIT
)
1623 local_irq_disable();
1628 if (!alloc_debug_processing(s
, c
->page
, object
, addr
))
1632 c
->page
->freelist
= object
[c
->offset
];
1638 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1639 * have the fastpath folded into their functions. So no function call
1640 * overhead for requests that can be satisfied on the fastpath.
1642 * The fastpath works by first checking if the lockless freelist can be used.
1643 * If not then __slab_alloc is called for slow processing.
1645 * Otherwise we can simply pick the next object from the lockless free list.
1647 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
1648 gfp_t gfpflags
, int node
, void *addr
)
1651 struct kmem_cache_cpu
*c
;
1652 unsigned long flags
;
1654 local_irq_save(flags
);
1655 c
= get_cpu_slab(s
, smp_processor_id());
1656 if (unlikely(!c
->freelist
|| !node_match(c
, node
)))
1658 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
1661 object
= c
->freelist
;
1662 c
->freelist
= object
[c
->offset
];
1663 stat(c
, ALLOC_FASTPATH
);
1665 local_irq_restore(flags
);
1667 if (unlikely((gfpflags
& __GFP_ZERO
) && object
))
1668 memset(object
, 0, c
->objsize
);
1673 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
1675 return slab_alloc(s
, gfpflags
, -1, __builtin_return_address(0));
1677 EXPORT_SYMBOL(kmem_cache_alloc
);
1680 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
1682 return slab_alloc(s
, gfpflags
, node
, __builtin_return_address(0));
1684 EXPORT_SYMBOL(kmem_cache_alloc_node
);
1688 * Slow patch handling. This may still be called frequently since objects
1689 * have a longer lifetime than the cpu slabs in most processing loads.
1691 * So we still attempt to reduce cache line usage. Just take the slab
1692 * lock and free the item. If there is no additional partial page
1693 * handling required then we can return immediately.
1695 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
1696 void *x
, void *addr
, unsigned int offset
)
1699 void **object
= (void *)x
;
1700 struct kmem_cache_cpu
*c
;
1702 c
= get_cpu_slab(s
, raw_smp_processor_id());
1703 stat(c
, FREE_SLOWPATH
);
1706 if (unlikely(SlabDebug(page
)))
1710 prior
= object
[offset
] = page
->freelist
;
1711 page
->freelist
= object
;
1714 if (unlikely(SlabFrozen(page
))) {
1715 stat(c
, FREE_FROZEN
);
1719 if (unlikely(!page
->inuse
))
1723 * Objects left in the slab. If it was not on the partial list before
1726 if (unlikely(!prior
)) {
1727 add_partial(get_node(s
, page_to_nid(page
)), page
, 1);
1728 stat(c
, FREE_ADD_PARTIAL
);
1738 * Slab still on the partial list.
1740 remove_partial(s
, page
);
1741 stat(c
, FREE_REMOVE_PARTIAL
);
1745 discard_slab(s
, page
);
1749 if (!free_debug_processing(s
, page
, x
, addr
))
1755 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1756 * can perform fastpath freeing without additional function calls.
1758 * The fastpath is only possible if we are freeing to the current cpu slab
1759 * of this processor. This typically the case if we have just allocated
1762 * If fastpath is not possible then fall back to __slab_free where we deal
1763 * with all sorts of special processing.
1765 static __always_inline
void slab_free(struct kmem_cache
*s
,
1766 struct page
*page
, void *x
, void *addr
)
1768 void **object
= (void *)x
;
1769 struct kmem_cache_cpu
*c
;
1770 unsigned long flags
;
1772 local_irq_save(flags
);
1773 c
= get_cpu_slab(s
, smp_processor_id());
1774 debug_check_no_locks_freed(object
, c
->objsize
);
1775 if (likely(page
== c
->page
&& c
->node
>= 0)) {
1776 object
[c
->offset
] = c
->freelist
;
1777 c
->freelist
= object
;
1778 stat(c
, FREE_FASTPATH
);
1780 __slab_free(s
, page
, x
, addr
, c
->offset
);
1782 local_irq_restore(flags
);
1785 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
1789 page
= virt_to_head_page(x
);
1791 slab_free(s
, page
, x
, __builtin_return_address(0));
1793 EXPORT_SYMBOL(kmem_cache_free
);
1795 /* Figure out on which slab object the object resides */
1796 static struct page
*get_object_page(const void *x
)
1798 struct page
*page
= virt_to_head_page(x
);
1800 if (!PageSlab(page
))
1807 * Object placement in a slab is made very easy because we always start at
1808 * offset 0. If we tune the size of the object to the alignment then we can
1809 * get the required alignment by putting one properly sized object after
1812 * Notice that the allocation order determines the sizes of the per cpu
1813 * caches. Each processor has always one slab available for allocations.
1814 * Increasing the allocation order reduces the number of times that slabs
1815 * must be moved on and off the partial lists and is therefore a factor in
1820 * Mininum / Maximum order of slab pages. This influences locking overhead
1821 * and slab fragmentation. A higher order reduces the number of partial slabs
1822 * and increases the number of allocations possible without having to
1823 * take the list_lock.
1825 static int slub_min_order
;
1826 static int slub_max_order
= DEFAULT_MAX_ORDER
;
1827 static int slub_min_objects
= DEFAULT_MIN_OBJECTS
;
1830 * Merge control. If this is set then no merging of slab caches will occur.
1831 * (Could be removed. This was introduced to pacify the merge skeptics.)
1833 static int slub_nomerge
;
1836 * Calculate the order of allocation given an slab object size.
1838 * The order of allocation has significant impact on performance and other
1839 * system components. Generally order 0 allocations should be preferred since
1840 * order 0 does not cause fragmentation in the page allocator. Larger objects
1841 * be problematic to put into order 0 slabs because there may be too much
1842 * unused space left. We go to a higher order if more than 1/8th of the slab
1845 * In order to reach satisfactory performance we must ensure that a minimum
1846 * number of objects is in one slab. Otherwise we may generate too much
1847 * activity on the partial lists which requires taking the list_lock. This is
1848 * less a concern for large slabs though which are rarely used.
1850 * slub_max_order specifies the order where we begin to stop considering the
1851 * number of objects in a slab as critical. If we reach slub_max_order then
1852 * we try to keep the page order as low as possible. So we accept more waste
1853 * of space in favor of a small page order.
1855 * Higher order allocations also allow the placement of more objects in a
1856 * slab and thereby reduce object handling overhead. If the user has
1857 * requested a higher mininum order then we start with that one instead of
1858 * the smallest order which will fit the object.
1860 static inline int slab_order(int size
, int min_objects
,
1861 int max_order
, int fract_leftover
)
1865 int min_order
= slub_min_order
;
1867 if ((PAGE_SIZE
<< min_order
) / size
> 65535)
1868 return get_order(size
* 65535) - 1;
1870 for (order
= max(min_order
,
1871 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
1872 order
<= max_order
; order
++) {
1874 unsigned long slab_size
= PAGE_SIZE
<< order
;
1876 if (slab_size
< min_objects
* size
)
1879 rem
= slab_size
% size
;
1881 if (rem
<= slab_size
/ fract_leftover
)
1889 static inline int calculate_order(int size
)
1896 * Attempt to find best configuration for a slab. This
1897 * works by first attempting to generate a layout with
1898 * the best configuration and backing off gradually.
1900 * First we reduce the acceptable waste in a slab. Then
1901 * we reduce the minimum objects required in a slab.
1903 min_objects
= slub_min_objects
;
1904 while (min_objects
> 1) {
1906 while (fraction
>= 4) {
1907 order
= slab_order(size
, min_objects
,
1908 slub_max_order
, fraction
);
1909 if (order
<= slub_max_order
)
1917 * We were unable to place multiple objects in a slab. Now
1918 * lets see if we can place a single object there.
1920 order
= slab_order(size
, 1, slub_max_order
, 1);
1921 if (order
<= slub_max_order
)
1925 * Doh this slab cannot be placed using slub_max_order.
1927 order
= slab_order(size
, 1, MAX_ORDER
, 1);
1928 if (order
<= MAX_ORDER
)
1934 * Figure out what the alignment of the objects will be.
1936 static unsigned long calculate_alignment(unsigned long flags
,
1937 unsigned long align
, unsigned long size
)
1940 * If the user wants hardware cache aligned objects then follow that
1941 * suggestion if the object is sufficiently large.
1943 * The hardware cache alignment cannot override the specified
1944 * alignment though. If that is greater then use it.
1946 if (flags
& SLAB_HWCACHE_ALIGN
) {
1947 unsigned long ralign
= cache_line_size();
1948 while (size
<= ralign
/ 2)
1950 align
= max(align
, ralign
);
1953 if (align
< ARCH_SLAB_MINALIGN
)
1954 align
= ARCH_SLAB_MINALIGN
;
1956 return ALIGN(align
, sizeof(void *));
1959 static void init_kmem_cache_cpu(struct kmem_cache
*s
,
1960 struct kmem_cache_cpu
*c
)
1965 c
->offset
= s
->offset
/ sizeof(void *);
1966 c
->objsize
= s
->objsize
;
1967 #ifdef CONFIG_SLUB_STATS
1968 memset(c
->stat
, 0, NR_SLUB_STAT_ITEMS
* sizeof(unsigned));
1972 static void init_kmem_cache_node(struct kmem_cache_node
*n
)
1975 spin_lock_init(&n
->list_lock
);
1976 INIT_LIST_HEAD(&n
->partial
);
1977 #ifdef CONFIG_SLUB_DEBUG
1978 atomic_long_set(&n
->nr_slabs
, 0);
1979 INIT_LIST_HEAD(&n
->full
);
1985 * Per cpu array for per cpu structures.
1987 * The per cpu array places all kmem_cache_cpu structures from one processor
1988 * close together meaning that it becomes possible that multiple per cpu
1989 * structures are contained in one cacheline. This may be particularly
1990 * beneficial for the kmalloc caches.
1992 * A desktop system typically has around 60-80 slabs. With 100 here we are
1993 * likely able to get per cpu structures for all caches from the array defined
1994 * here. We must be able to cover all kmalloc caches during bootstrap.
1996 * If the per cpu array is exhausted then fall back to kmalloc
1997 * of individual cachelines. No sharing is possible then.
1999 #define NR_KMEM_CACHE_CPU 100
2001 static DEFINE_PER_CPU(struct kmem_cache_cpu
,
2002 kmem_cache_cpu
)[NR_KMEM_CACHE_CPU
];
2004 static DEFINE_PER_CPU(struct kmem_cache_cpu
*, kmem_cache_cpu_free
);
2005 static cpumask_t kmem_cach_cpu_free_init_once
= CPU_MASK_NONE
;
2007 static struct kmem_cache_cpu
*alloc_kmem_cache_cpu(struct kmem_cache
*s
,
2008 int cpu
, gfp_t flags
)
2010 struct kmem_cache_cpu
*c
= per_cpu(kmem_cache_cpu_free
, cpu
);
2013 per_cpu(kmem_cache_cpu_free
, cpu
) =
2014 (void *)c
->freelist
;
2016 /* Table overflow: So allocate ourselves */
2018 ALIGN(sizeof(struct kmem_cache_cpu
), cache_line_size()),
2019 flags
, cpu_to_node(cpu
));
2024 init_kmem_cache_cpu(s
, c
);
2028 static void free_kmem_cache_cpu(struct kmem_cache_cpu
*c
, int cpu
)
2030 if (c
< per_cpu(kmem_cache_cpu
, cpu
) ||
2031 c
> per_cpu(kmem_cache_cpu
, cpu
) + NR_KMEM_CACHE_CPU
) {
2035 c
->freelist
= (void *)per_cpu(kmem_cache_cpu_free
, cpu
);
2036 per_cpu(kmem_cache_cpu_free
, cpu
) = c
;
2039 static void free_kmem_cache_cpus(struct kmem_cache
*s
)
2043 for_each_online_cpu(cpu
) {
2044 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
2047 s
->cpu_slab
[cpu
] = NULL
;
2048 free_kmem_cache_cpu(c
, cpu
);
2053 static int alloc_kmem_cache_cpus(struct kmem_cache
*s
, gfp_t flags
)
2057 for_each_online_cpu(cpu
) {
2058 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
2063 c
= alloc_kmem_cache_cpu(s
, cpu
, flags
);
2065 free_kmem_cache_cpus(s
);
2068 s
->cpu_slab
[cpu
] = c
;
2074 * Initialize the per cpu array.
2076 static void init_alloc_cpu_cpu(int cpu
)
2080 if (cpu_isset(cpu
, kmem_cach_cpu_free_init_once
))
2083 for (i
= NR_KMEM_CACHE_CPU
- 1; i
>= 0; i
--)
2084 free_kmem_cache_cpu(&per_cpu(kmem_cache_cpu
, cpu
)[i
], cpu
);
2086 cpu_set(cpu
, kmem_cach_cpu_free_init_once
);
2089 static void __init
init_alloc_cpu(void)
2093 for_each_online_cpu(cpu
)
2094 init_alloc_cpu_cpu(cpu
);
2098 static inline void free_kmem_cache_cpus(struct kmem_cache
*s
) {}
2099 static inline void init_alloc_cpu(void) {}
2101 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
, gfp_t flags
)
2103 init_kmem_cache_cpu(s
, &s
->cpu_slab
);
2110 * No kmalloc_node yet so do it by hand. We know that this is the first
2111 * slab on the node for this slabcache. There are no concurrent accesses
2114 * Note that this function only works on the kmalloc_node_cache
2115 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2116 * memory on a fresh node that has no slab structures yet.
2118 static struct kmem_cache_node
*early_kmem_cache_node_alloc(gfp_t gfpflags
,
2122 struct kmem_cache_node
*n
;
2123 unsigned long flags
;
2125 BUG_ON(kmalloc_caches
->size
< sizeof(struct kmem_cache_node
));
2127 page
= new_slab(kmalloc_caches
, gfpflags
, node
);
2130 if (page_to_nid(page
) != node
) {
2131 printk(KERN_ERR
"SLUB: Unable to allocate memory from "
2133 printk(KERN_ERR
"SLUB: Allocating a useless per node structure "
2134 "in order to be able to continue\n");
2139 page
->freelist
= get_freepointer(kmalloc_caches
, n
);
2141 kmalloc_caches
->node
[node
] = n
;
2142 #ifdef CONFIG_SLUB_DEBUG
2143 init_object(kmalloc_caches
, n
, 1);
2144 init_tracking(kmalloc_caches
, n
);
2146 init_kmem_cache_node(n
);
2147 inc_slabs_node(kmalloc_caches
, node
);
2150 * lockdep requires consistent irq usage for each lock
2151 * so even though there cannot be a race this early in
2152 * the boot sequence, we still disable irqs.
2154 local_irq_save(flags
);
2155 add_partial(n
, page
, 0);
2156 local_irq_restore(flags
);
2160 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2164 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2165 struct kmem_cache_node
*n
= s
->node
[node
];
2166 if (n
&& n
!= &s
->local_node
)
2167 kmem_cache_free(kmalloc_caches
, n
);
2168 s
->node
[node
] = NULL
;
2172 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
2177 if (slab_state
>= UP
)
2178 local_node
= page_to_nid(virt_to_page(s
));
2182 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2183 struct kmem_cache_node
*n
;
2185 if (local_node
== node
)
2188 if (slab_state
== DOWN
) {
2189 n
= early_kmem_cache_node_alloc(gfpflags
,
2193 n
= kmem_cache_alloc_node(kmalloc_caches
,
2197 free_kmem_cache_nodes(s
);
2203 init_kmem_cache_node(n
);
2208 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2212 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
2214 init_kmem_cache_node(&s
->local_node
);
2220 * calculate_sizes() determines the order and the distribution of data within
2223 static int calculate_sizes(struct kmem_cache
*s
)
2225 unsigned long flags
= s
->flags
;
2226 unsigned long size
= s
->objsize
;
2227 unsigned long align
= s
->align
;
2231 * Round up object size to the next word boundary. We can only
2232 * place the free pointer at word boundaries and this determines
2233 * the possible location of the free pointer.
2235 size
= ALIGN(size
, sizeof(void *));
2237 #ifdef CONFIG_SLUB_DEBUG
2239 * Determine if we can poison the object itself. If the user of
2240 * the slab may touch the object after free or before allocation
2241 * then we should never poison the object itself.
2243 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
2245 s
->flags
|= __OBJECT_POISON
;
2247 s
->flags
&= ~__OBJECT_POISON
;
2251 * If we are Redzoning then check if there is some space between the
2252 * end of the object and the free pointer. If not then add an
2253 * additional word to have some bytes to store Redzone information.
2255 if ((flags
& SLAB_RED_ZONE
) && size
== s
->objsize
)
2256 size
+= sizeof(void *);
2260 * With that we have determined the number of bytes in actual use
2261 * by the object. This is the potential offset to the free pointer.
2265 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
2268 * Relocate free pointer after the object if it is not
2269 * permitted to overwrite the first word of the object on
2272 * This is the case if we do RCU, have a constructor or
2273 * destructor or are poisoning the objects.
2276 size
+= sizeof(void *);
2279 #ifdef CONFIG_SLUB_DEBUG
2280 if (flags
& SLAB_STORE_USER
)
2282 * Need to store information about allocs and frees after
2285 size
+= 2 * sizeof(struct track
);
2287 if (flags
& SLAB_RED_ZONE
)
2289 * Add some empty padding so that we can catch
2290 * overwrites from earlier objects rather than let
2291 * tracking information or the free pointer be
2292 * corrupted if an user writes before the start
2295 size
+= sizeof(void *);
2299 * Determine the alignment based on various parameters that the
2300 * user specified and the dynamic determination of cache line size
2303 align
= calculate_alignment(flags
, align
, s
->objsize
);
2306 * SLUB stores one object immediately after another beginning from
2307 * offset 0. In order to align the objects we have to simply size
2308 * each object to conform to the alignment.
2310 size
= ALIGN(size
, align
);
2313 if ((flags
& __KMALLOC_CACHE
) &&
2314 PAGE_SIZE
/ size
< slub_min_objects
) {
2316 * Kmalloc cache that would not have enough objects in
2317 * an order 0 page. Kmalloc slabs can fallback to
2318 * page allocator order 0 allocs so take a reasonably large
2319 * order that will allows us a good number of objects.
2321 order
= max(slub_max_order
, PAGE_ALLOC_COSTLY_ORDER
);
2322 s
->flags
|= __PAGE_ALLOC_FALLBACK
;
2323 s
->allocflags
|= __GFP_NOWARN
;
2325 order
= calculate_order(size
);
2332 s
->allocflags
|= __GFP_COMP
;
2334 if (s
->flags
& SLAB_CACHE_DMA
)
2335 s
->allocflags
|= SLUB_DMA
;
2337 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
2338 s
->allocflags
|= __GFP_RECLAIMABLE
;
2341 * Determine the number of objects per slab
2343 s
->oo
= oo_make(order
, size
);
2345 return !!oo_objects(s
->oo
);
2349 static int kmem_cache_open(struct kmem_cache
*s
, gfp_t gfpflags
,
2350 const char *name
, size_t size
,
2351 size_t align
, unsigned long flags
,
2352 void (*ctor
)(struct kmem_cache
*, void *))
2354 memset(s
, 0, kmem_size
);
2359 s
->flags
= kmem_cache_flags(size
, flags
, name
, ctor
);
2361 if (!calculate_sizes(s
))
2366 s
->remote_node_defrag_ratio
= 100;
2368 if (!init_kmem_cache_nodes(s
, gfpflags
& ~SLUB_DMA
))
2371 if (alloc_kmem_cache_cpus(s
, gfpflags
& ~SLUB_DMA
))
2373 free_kmem_cache_nodes(s
);
2375 if (flags
& SLAB_PANIC
)
2376 panic("Cannot create slab %s size=%lu realsize=%u "
2377 "order=%u offset=%u flags=%lx\n",
2378 s
->name
, (unsigned long)size
, s
->size
, oo_order(s
->oo
),
2384 * Check if a given pointer is valid
2386 int kmem_ptr_validate(struct kmem_cache
*s
, const void *object
)
2390 page
= get_object_page(object
);
2392 if (!page
|| s
!= page
->slab
)
2393 /* No slab or wrong slab */
2396 if (!check_valid_pointer(s
, page
, object
))
2400 * We could also check if the object is on the slabs freelist.
2401 * But this would be too expensive and it seems that the main
2402 * purpose of kmem_ptr_valid() is to check if the object belongs
2403 * to a certain slab.
2407 EXPORT_SYMBOL(kmem_ptr_validate
);
2410 * Determine the size of a slab object
2412 unsigned int kmem_cache_size(struct kmem_cache
*s
)
2416 EXPORT_SYMBOL(kmem_cache_size
);
2418 const char *kmem_cache_name(struct kmem_cache
*s
)
2422 EXPORT_SYMBOL(kmem_cache_name
);
2424 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
2427 #ifdef CONFIG_SLUB_DEBUG
2428 void *addr
= page_address(page
);
2430 DECLARE_BITMAP(map
, page
->objects
);
2432 bitmap_zero(map
, page
->objects
);
2433 slab_err(s
, page
, "%s", text
);
2435 for_each_free_object(p
, s
, page
->freelist
)
2436 set_bit(slab_index(p
, s
, addr
), map
);
2438 for_each_object(p
, s
, addr
, page
->objects
) {
2440 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
2441 printk(KERN_ERR
"INFO: Object 0x%p @offset=%tu\n",
2443 print_tracking(s
, p
);
2451 * Attempt to free all partial slabs on a node.
2453 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
2455 unsigned long flags
;
2456 struct page
*page
, *h
;
2458 spin_lock_irqsave(&n
->list_lock
, flags
);
2459 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
2461 list_del(&page
->lru
);
2462 discard_slab(s
, page
);
2465 list_slab_objects(s
, page
,
2466 "Objects remaining on kmem_cache_close()");
2469 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2473 * Release all resources used by a slab cache.
2475 static inline int kmem_cache_close(struct kmem_cache
*s
)
2481 /* Attempt to free all objects */
2482 free_kmem_cache_cpus(s
);
2483 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2484 struct kmem_cache_node
*n
= get_node(s
, node
);
2487 if (n
->nr_partial
|| slabs_node(s
, node
))
2490 free_kmem_cache_nodes(s
);
2495 * Close a cache and release the kmem_cache structure
2496 * (must be used for caches created using kmem_cache_create)
2498 void kmem_cache_destroy(struct kmem_cache
*s
)
2500 down_write(&slub_lock
);
2504 up_write(&slub_lock
);
2505 if (kmem_cache_close(s
)) {
2506 printk(KERN_ERR
"SLUB %s: %s called for cache that "
2507 "still has objects.\n", s
->name
, __func__
);
2510 sysfs_slab_remove(s
);
2512 up_write(&slub_lock
);
2514 EXPORT_SYMBOL(kmem_cache_destroy
);
2516 /********************************************************************
2518 *******************************************************************/
2520 struct kmem_cache kmalloc_caches
[PAGE_SHIFT
+ 1] __cacheline_aligned
;
2521 EXPORT_SYMBOL(kmalloc_caches
);
2523 static int __init
setup_slub_min_order(char *str
)
2525 get_option(&str
, &slub_min_order
);
2530 __setup("slub_min_order=", setup_slub_min_order
);
2532 static int __init
setup_slub_max_order(char *str
)
2534 get_option(&str
, &slub_max_order
);
2539 __setup("slub_max_order=", setup_slub_max_order
);
2541 static int __init
setup_slub_min_objects(char *str
)
2543 get_option(&str
, &slub_min_objects
);
2548 __setup("slub_min_objects=", setup_slub_min_objects
);
2550 static int __init
setup_slub_nomerge(char *str
)
2556 __setup("slub_nomerge", setup_slub_nomerge
);
2558 static struct kmem_cache
*create_kmalloc_cache(struct kmem_cache
*s
,
2559 const char *name
, int size
, gfp_t gfp_flags
)
2561 unsigned int flags
= 0;
2563 if (gfp_flags
& SLUB_DMA
)
2564 flags
= SLAB_CACHE_DMA
;
2566 down_write(&slub_lock
);
2567 if (!kmem_cache_open(s
, gfp_flags
, name
, size
, ARCH_KMALLOC_MINALIGN
,
2568 flags
| __KMALLOC_CACHE
, NULL
))
2571 list_add(&s
->list
, &slab_caches
);
2572 up_write(&slub_lock
);
2573 if (sysfs_slab_add(s
))
2578 panic("Creation of kmalloc slab %s size=%d failed.\n", name
, size
);
2581 #ifdef CONFIG_ZONE_DMA
2582 static struct kmem_cache
*kmalloc_caches_dma
[PAGE_SHIFT
+ 1];
2584 static void sysfs_add_func(struct work_struct
*w
)
2586 struct kmem_cache
*s
;
2588 down_write(&slub_lock
);
2589 list_for_each_entry(s
, &slab_caches
, list
) {
2590 if (s
->flags
& __SYSFS_ADD_DEFERRED
) {
2591 s
->flags
&= ~__SYSFS_ADD_DEFERRED
;
2595 up_write(&slub_lock
);
2598 static DECLARE_WORK(sysfs_add_work
, sysfs_add_func
);
2600 static noinline
struct kmem_cache
*dma_kmalloc_cache(int index
, gfp_t flags
)
2602 struct kmem_cache
*s
;
2606 s
= kmalloc_caches_dma
[index
];
2610 /* Dynamically create dma cache */
2611 if (flags
& __GFP_WAIT
)
2612 down_write(&slub_lock
);
2614 if (!down_write_trylock(&slub_lock
))
2618 if (kmalloc_caches_dma
[index
])
2621 realsize
= kmalloc_caches
[index
].objsize
;
2622 text
= kasprintf(flags
& ~SLUB_DMA
, "kmalloc_dma-%d",
2623 (unsigned int)realsize
);
2624 s
= kmalloc(kmem_size
, flags
& ~SLUB_DMA
);
2626 if (!s
|| !text
|| !kmem_cache_open(s
, flags
, text
,
2627 realsize
, ARCH_KMALLOC_MINALIGN
,
2628 SLAB_CACHE_DMA
|__SYSFS_ADD_DEFERRED
, NULL
)) {
2634 list_add(&s
->list
, &slab_caches
);
2635 kmalloc_caches_dma
[index
] = s
;
2637 schedule_work(&sysfs_add_work
);
2640 up_write(&slub_lock
);
2642 return kmalloc_caches_dma
[index
];
2647 * Conversion table for small slabs sizes / 8 to the index in the
2648 * kmalloc array. This is necessary for slabs < 192 since we have non power
2649 * of two cache sizes there. The size of larger slabs can be determined using
2652 static s8 size_index
[24] = {
2679 static struct kmem_cache
*get_slab(size_t size
, gfp_t flags
)
2685 return ZERO_SIZE_PTR
;
2687 index
= size_index
[(size
- 1) / 8];
2689 index
= fls(size
- 1);
2691 #ifdef CONFIG_ZONE_DMA
2692 if (unlikely((flags
& SLUB_DMA
)))
2693 return dma_kmalloc_cache(index
, flags
);
2696 return &kmalloc_caches
[index
];
2699 void *__kmalloc(size_t size
, gfp_t flags
)
2701 struct kmem_cache
*s
;
2703 if (unlikely(size
> PAGE_SIZE
))
2704 return kmalloc_large(size
, flags
);
2706 s
= get_slab(size
, flags
);
2708 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2711 return slab_alloc(s
, flags
, -1, __builtin_return_address(0));
2713 EXPORT_SYMBOL(__kmalloc
);
2715 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
2717 struct page
*page
= alloc_pages_node(node
, flags
| __GFP_COMP
,
2721 return page_address(page
);
2727 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
2729 struct kmem_cache
*s
;
2731 if (unlikely(size
> PAGE_SIZE
))
2732 return kmalloc_large_node(size
, flags
, node
);
2734 s
= get_slab(size
, flags
);
2736 if (unlikely(ZERO_OR_NULL_PTR(s
)))
2739 return slab_alloc(s
, flags
, node
, __builtin_return_address(0));
2741 EXPORT_SYMBOL(__kmalloc_node
);
2744 size_t ksize(const void *object
)
2747 struct kmem_cache
*s
;
2749 if (unlikely(object
== ZERO_SIZE_PTR
))
2752 page
= virt_to_head_page(object
);
2754 if (unlikely(!PageSlab(page
)))
2755 return PAGE_SIZE
<< compound_order(page
);
2759 #ifdef CONFIG_SLUB_DEBUG
2761 * Debugging requires use of the padding between object
2762 * and whatever may come after it.
2764 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
2769 * If we have the need to store the freelist pointer
2770 * back there or track user information then we can
2771 * only use the space before that information.
2773 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
2776 * Else we can use all the padding etc for the allocation
2780 EXPORT_SYMBOL(ksize
);
2782 void kfree(const void *x
)
2785 void *object
= (void *)x
;
2787 if (unlikely(ZERO_OR_NULL_PTR(x
)))
2790 page
= virt_to_head_page(x
);
2791 if (unlikely(!PageSlab(page
))) {
2795 slab_free(page
->slab
, page
, object
, __builtin_return_address(0));
2797 EXPORT_SYMBOL(kfree
);
2800 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2801 * the remaining slabs by the number of items in use. The slabs with the
2802 * most items in use come first. New allocations will then fill those up
2803 * and thus they can be removed from the partial lists.
2805 * The slabs with the least items are placed last. This results in them
2806 * being allocated from last increasing the chance that the last objects
2807 * are freed in them.
2809 int kmem_cache_shrink(struct kmem_cache
*s
)
2813 struct kmem_cache_node
*n
;
2816 int objects
= oo_objects(s
->oo
);
2817 struct list_head
*slabs_by_inuse
=
2818 kmalloc(sizeof(struct list_head
) * objects
, GFP_KERNEL
);
2819 unsigned long flags
;
2821 if (!slabs_by_inuse
)
2825 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2826 n
= get_node(s
, node
);
2831 for (i
= 0; i
< objects
; i
++)
2832 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
2834 spin_lock_irqsave(&n
->list_lock
, flags
);
2837 * Build lists indexed by the items in use in each slab.
2839 * Note that concurrent frees may occur while we hold the
2840 * list_lock. page->inuse here is the upper limit.
2842 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
2843 if (!page
->inuse
&& slab_trylock(page
)) {
2845 * Must hold slab lock here because slab_free
2846 * may have freed the last object and be
2847 * waiting to release the slab.
2849 list_del(&page
->lru
);
2852 discard_slab(s
, page
);
2854 list_move(&page
->lru
,
2855 slabs_by_inuse
+ page
->inuse
);
2860 * Rebuild the partial list with the slabs filled up most
2861 * first and the least used slabs at the end.
2863 for (i
= objects
- 1; i
>= 0; i
--)
2864 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
2866 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2869 kfree(slabs_by_inuse
);
2872 EXPORT_SYMBOL(kmem_cache_shrink
);
2874 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
2875 static int slab_mem_going_offline_callback(void *arg
)
2877 struct kmem_cache
*s
;
2879 down_read(&slub_lock
);
2880 list_for_each_entry(s
, &slab_caches
, list
)
2881 kmem_cache_shrink(s
);
2882 up_read(&slub_lock
);
2887 static void slab_mem_offline_callback(void *arg
)
2889 struct kmem_cache_node
*n
;
2890 struct kmem_cache
*s
;
2891 struct memory_notify
*marg
= arg
;
2894 offline_node
= marg
->status_change_nid
;
2897 * If the node still has available memory. we need kmem_cache_node
2900 if (offline_node
< 0)
2903 down_read(&slub_lock
);
2904 list_for_each_entry(s
, &slab_caches
, list
) {
2905 n
= get_node(s
, offline_node
);
2908 * if n->nr_slabs > 0, slabs still exist on the node
2909 * that is going down. We were unable to free them,
2910 * and offline_pages() function shoudn't call this
2911 * callback. So, we must fail.
2913 BUG_ON(slabs_node(s
, offline_node
));
2915 s
->node
[offline_node
] = NULL
;
2916 kmem_cache_free(kmalloc_caches
, n
);
2919 up_read(&slub_lock
);
2922 static int slab_mem_going_online_callback(void *arg
)
2924 struct kmem_cache_node
*n
;
2925 struct kmem_cache
*s
;
2926 struct memory_notify
*marg
= arg
;
2927 int nid
= marg
->status_change_nid
;
2931 * If the node's memory is already available, then kmem_cache_node is
2932 * already created. Nothing to do.
2938 * We are bringing a node online. No memory is availabe yet. We must
2939 * allocate a kmem_cache_node structure in order to bring the node
2942 down_read(&slub_lock
);
2943 list_for_each_entry(s
, &slab_caches
, list
) {
2945 * XXX: kmem_cache_alloc_node will fallback to other nodes
2946 * since memory is not yet available from the node that
2949 n
= kmem_cache_alloc(kmalloc_caches
, GFP_KERNEL
);
2954 init_kmem_cache_node(n
);
2958 up_read(&slub_lock
);
2962 static int slab_memory_callback(struct notifier_block
*self
,
2963 unsigned long action
, void *arg
)
2968 case MEM_GOING_ONLINE
:
2969 ret
= slab_mem_going_online_callback(arg
);
2971 case MEM_GOING_OFFLINE
:
2972 ret
= slab_mem_going_offline_callback(arg
);
2975 case MEM_CANCEL_ONLINE
:
2976 slab_mem_offline_callback(arg
);
2979 case MEM_CANCEL_OFFLINE
:
2983 ret
= notifier_from_errno(ret
);
2987 #endif /* CONFIG_MEMORY_HOTPLUG */
2989 /********************************************************************
2990 * Basic setup of slabs
2991 *******************************************************************/
2993 void __init
kmem_cache_init(void)
3002 * Must first have the slab cache available for the allocations of the
3003 * struct kmem_cache_node's. There is special bootstrap code in
3004 * kmem_cache_open for slab_state == DOWN.
3006 create_kmalloc_cache(&kmalloc_caches
[0], "kmem_cache_node",
3007 sizeof(struct kmem_cache_node
), GFP_KERNEL
);
3008 kmalloc_caches
[0].refcount
= -1;
3011 hotplug_memory_notifier(slab_memory_callback
, 1);
3014 /* Able to allocate the per node structures */
3015 slab_state
= PARTIAL
;
3017 /* Caches that are not of the two-to-the-power-of size */
3018 if (KMALLOC_MIN_SIZE
<= 64) {
3019 create_kmalloc_cache(&kmalloc_caches
[1],
3020 "kmalloc-96", 96, GFP_KERNEL
);
3023 if (KMALLOC_MIN_SIZE
<= 128) {
3024 create_kmalloc_cache(&kmalloc_caches
[2],
3025 "kmalloc-192", 192, GFP_KERNEL
);
3029 for (i
= KMALLOC_SHIFT_LOW
; i
<= PAGE_SHIFT
; i
++) {
3030 create_kmalloc_cache(&kmalloc_caches
[i
],
3031 "kmalloc", 1 << i
, GFP_KERNEL
);
3037 * Patch up the size_index table if we have strange large alignment
3038 * requirements for the kmalloc array. This is only the case for
3039 * MIPS it seems. The standard arches will not generate any code here.
3041 * Largest permitted alignment is 256 bytes due to the way we
3042 * handle the index determination for the smaller caches.
3044 * Make sure that nothing crazy happens if someone starts tinkering
3045 * around with ARCH_KMALLOC_MINALIGN
3047 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 256 ||
3048 (KMALLOC_MIN_SIZE
& (KMALLOC_MIN_SIZE
- 1)));
3050 for (i
= 8; i
< KMALLOC_MIN_SIZE
; i
+= 8)
3051 size_index
[(i
- 1) / 8] = KMALLOC_SHIFT_LOW
;
3055 /* Provide the correct kmalloc names now that the caches are up */
3056 for (i
= KMALLOC_SHIFT_LOW
; i
<= PAGE_SHIFT
; i
++)
3057 kmalloc_caches
[i
]. name
=
3058 kasprintf(GFP_KERNEL
, "kmalloc-%d", 1 << i
);
3061 register_cpu_notifier(&slab_notifier
);
3062 kmem_size
= offsetof(struct kmem_cache
, cpu_slab
) +
3063 nr_cpu_ids
* sizeof(struct kmem_cache_cpu
*);
3065 kmem_size
= sizeof(struct kmem_cache
);
3069 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3070 " CPUs=%d, Nodes=%d\n",
3071 caches
, cache_line_size(),
3072 slub_min_order
, slub_max_order
, slub_min_objects
,
3073 nr_cpu_ids
, nr_node_ids
);
3077 * Find a mergeable slab cache
3079 static int slab_unmergeable(struct kmem_cache
*s
)
3081 if (slub_nomerge
|| (s
->flags
& SLUB_NEVER_MERGE
))
3084 if ((s
->flags
& __PAGE_ALLOC_FALLBACK
))
3091 * We may have set a slab to be unmergeable during bootstrap.
3093 if (s
->refcount
< 0)
3099 static struct kmem_cache
*find_mergeable(size_t size
,
3100 size_t align
, unsigned long flags
, const char *name
,
3101 void (*ctor
)(struct kmem_cache
*, void *))
3103 struct kmem_cache
*s
;
3105 if (slub_nomerge
|| (flags
& SLUB_NEVER_MERGE
))
3111 size
= ALIGN(size
, sizeof(void *));
3112 align
= calculate_alignment(flags
, align
, size
);
3113 size
= ALIGN(size
, align
);
3114 flags
= kmem_cache_flags(size
, flags
, name
, NULL
);
3116 list_for_each_entry(s
, &slab_caches
, list
) {
3117 if (slab_unmergeable(s
))
3123 if ((flags
& SLUB_MERGE_SAME
) != (s
->flags
& SLUB_MERGE_SAME
))
3126 * Check if alignment is compatible.
3127 * Courtesy of Adrian Drzewiecki
3129 if ((s
->size
& ~(align
- 1)) != s
->size
)
3132 if (s
->size
- size
>= sizeof(void *))
3140 struct kmem_cache
*kmem_cache_create(const char *name
, size_t size
,
3141 size_t align
, unsigned long flags
,
3142 void (*ctor
)(struct kmem_cache
*, void *))
3144 struct kmem_cache
*s
;
3146 down_write(&slub_lock
);
3147 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3153 * Adjust the object sizes so that we clear
3154 * the complete object on kzalloc.
3156 s
->objsize
= max(s
->objsize
, (int)size
);
3159 * And then we need to update the object size in the
3160 * per cpu structures
3162 for_each_online_cpu(cpu
)
3163 get_cpu_slab(s
, cpu
)->objsize
= s
->objsize
;
3165 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3166 up_write(&slub_lock
);
3168 if (sysfs_slab_alias(s
, name
))
3173 s
= kmalloc(kmem_size
, GFP_KERNEL
);
3175 if (kmem_cache_open(s
, GFP_KERNEL
, name
,
3176 size
, align
, flags
, ctor
)) {
3177 list_add(&s
->list
, &slab_caches
);
3178 up_write(&slub_lock
);
3179 if (sysfs_slab_add(s
))
3185 up_write(&slub_lock
);
3188 if (flags
& SLAB_PANIC
)
3189 panic("Cannot create slabcache %s\n", name
);
3194 EXPORT_SYMBOL(kmem_cache_create
);
3198 * Use the cpu notifier to insure that the cpu slabs are flushed when
3201 static int __cpuinit
slab_cpuup_callback(struct notifier_block
*nfb
,
3202 unsigned long action
, void *hcpu
)
3204 long cpu
= (long)hcpu
;
3205 struct kmem_cache
*s
;
3206 unsigned long flags
;
3209 case CPU_UP_PREPARE
:
3210 case CPU_UP_PREPARE_FROZEN
:
3211 init_alloc_cpu_cpu(cpu
);
3212 down_read(&slub_lock
);
3213 list_for_each_entry(s
, &slab_caches
, list
)
3214 s
->cpu_slab
[cpu
] = alloc_kmem_cache_cpu(s
, cpu
,
3216 up_read(&slub_lock
);
3219 case CPU_UP_CANCELED
:
3220 case CPU_UP_CANCELED_FROZEN
:
3222 case CPU_DEAD_FROZEN
:
3223 down_read(&slub_lock
);
3224 list_for_each_entry(s
, &slab_caches
, list
) {
3225 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3227 local_irq_save(flags
);
3228 __flush_cpu_slab(s
, cpu
);
3229 local_irq_restore(flags
);
3230 free_kmem_cache_cpu(c
, cpu
);
3231 s
->cpu_slab
[cpu
] = NULL
;
3233 up_read(&slub_lock
);
3241 static struct notifier_block __cpuinitdata slab_notifier
= {
3242 .notifier_call
= slab_cpuup_callback
3247 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, void *caller
)
3249 struct kmem_cache
*s
;
3251 if (unlikely(size
> PAGE_SIZE
))
3252 return kmalloc_large(size
, gfpflags
);
3254 s
= get_slab(size
, gfpflags
);
3256 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3259 return slab_alloc(s
, gfpflags
, -1, caller
);
3262 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3263 int node
, void *caller
)
3265 struct kmem_cache
*s
;
3267 if (unlikely(size
> PAGE_SIZE
))
3268 return kmalloc_large_node(size
, gfpflags
, node
);
3270 s
= get_slab(size
, gfpflags
);
3272 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3275 return slab_alloc(s
, gfpflags
, node
, caller
);
3278 #if (defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)) || defined(CONFIG_SLABINFO)
3279 static unsigned long count_partial(struct kmem_cache_node
*n
)
3281 unsigned long flags
;
3282 unsigned long x
= 0;
3285 spin_lock_irqsave(&n
->list_lock
, flags
);
3286 list_for_each_entry(page
, &n
->partial
, lru
)
3288 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3293 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
3294 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3298 void *addr
= page_address(page
);
3300 if (!check_slab(s
, page
) ||
3301 !on_freelist(s
, page
, NULL
))
3304 /* Now we know that a valid freelist exists */
3305 bitmap_zero(map
, page
->objects
);
3307 for_each_free_object(p
, s
, page
->freelist
) {
3308 set_bit(slab_index(p
, s
, addr
), map
);
3309 if (!check_object(s
, page
, p
, 0))
3313 for_each_object(p
, s
, addr
, page
->objects
)
3314 if (!test_bit(slab_index(p
, s
, addr
), map
))
3315 if (!check_object(s
, page
, p
, 1))
3320 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
3323 if (slab_trylock(page
)) {
3324 validate_slab(s
, page
, map
);
3327 printk(KERN_INFO
"SLUB %s: Skipped busy slab 0x%p\n",
3330 if (s
->flags
& DEBUG_DEFAULT_FLAGS
) {
3331 if (!SlabDebug(page
))
3332 printk(KERN_ERR
"SLUB %s: SlabDebug not set "
3333 "on slab 0x%p\n", s
->name
, page
);
3335 if (SlabDebug(page
))
3336 printk(KERN_ERR
"SLUB %s: SlabDebug set on "
3337 "slab 0x%p\n", s
->name
, page
);
3341 static int validate_slab_node(struct kmem_cache
*s
,
3342 struct kmem_cache_node
*n
, unsigned long *map
)
3344 unsigned long count
= 0;
3346 unsigned long flags
;
3348 spin_lock_irqsave(&n
->list_lock
, flags
);
3350 list_for_each_entry(page
, &n
->partial
, lru
) {
3351 validate_slab_slab(s
, page
, map
);
3354 if (count
!= n
->nr_partial
)
3355 printk(KERN_ERR
"SLUB %s: %ld partial slabs counted but "
3356 "counter=%ld\n", s
->name
, count
, n
->nr_partial
);
3358 if (!(s
->flags
& SLAB_STORE_USER
))
3361 list_for_each_entry(page
, &n
->full
, lru
) {
3362 validate_slab_slab(s
, page
, map
);
3365 if (count
!= atomic_long_read(&n
->nr_slabs
))
3366 printk(KERN_ERR
"SLUB: %s %ld slabs counted but "
3367 "counter=%ld\n", s
->name
, count
,
3368 atomic_long_read(&n
->nr_slabs
));
3371 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3375 static long validate_slab_cache(struct kmem_cache
*s
)
3378 unsigned long count
= 0;
3379 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->oo
)) *
3380 sizeof(unsigned long), GFP_KERNEL
);
3386 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3387 struct kmem_cache_node
*n
= get_node(s
, node
);
3389 count
+= validate_slab_node(s
, n
, map
);
3395 #ifdef SLUB_RESILIENCY_TEST
3396 static void resiliency_test(void)
3400 printk(KERN_ERR
"SLUB resiliency testing\n");
3401 printk(KERN_ERR
"-----------------------\n");
3402 printk(KERN_ERR
"A. Corruption after allocation\n");
3404 p
= kzalloc(16, GFP_KERNEL
);
3406 printk(KERN_ERR
"\n1. kmalloc-16: Clobber Redzone/next pointer"
3407 " 0x12->0x%p\n\n", p
+ 16);
3409 validate_slab_cache(kmalloc_caches
+ 4);
3411 /* Hmmm... The next two are dangerous */
3412 p
= kzalloc(32, GFP_KERNEL
);
3413 p
[32 + sizeof(void *)] = 0x34;
3414 printk(KERN_ERR
"\n2. kmalloc-32: Clobber next pointer/next slab"
3415 " 0x34 -> -0x%p\n", p
);
3417 "If allocated object is overwritten then not detectable\n\n");
3419 validate_slab_cache(kmalloc_caches
+ 5);
3420 p
= kzalloc(64, GFP_KERNEL
);
3421 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
3423 printk(KERN_ERR
"\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
3426 "If allocated object is overwritten then not detectable\n\n");
3427 validate_slab_cache(kmalloc_caches
+ 6);
3429 printk(KERN_ERR
"\nB. Corruption after free\n");
3430 p
= kzalloc(128, GFP_KERNEL
);
3433 printk(KERN_ERR
"1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
3434 validate_slab_cache(kmalloc_caches
+ 7);
3436 p
= kzalloc(256, GFP_KERNEL
);
3439 printk(KERN_ERR
"\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
3441 validate_slab_cache(kmalloc_caches
+ 8);
3443 p
= kzalloc(512, GFP_KERNEL
);
3446 printk(KERN_ERR
"\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
3447 validate_slab_cache(kmalloc_caches
+ 9);
3450 static void resiliency_test(void) {};
3454 * Generate lists of code addresses where slabcache objects are allocated
3459 unsigned long count
;
3472 unsigned long count
;
3473 struct location
*loc
;
3476 static void free_loc_track(struct loc_track
*t
)
3479 free_pages((unsigned long)t
->loc
,
3480 get_order(sizeof(struct location
) * t
->max
));
3483 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
3488 order
= get_order(sizeof(struct location
) * max
);
3490 l
= (void *)__get_free_pages(flags
, order
);
3495 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
3503 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
3504 const struct track
*track
)
3506 long start
, end
, pos
;
3509 unsigned long age
= jiffies
- track
->when
;
3515 pos
= start
+ (end
- start
+ 1) / 2;
3518 * There is nothing at "end". If we end up there
3519 * we need to add something to before end.
3524 caddr
= t
->loc
[pos
].addr
;
3525 if (track
->addr
== caddr
) {
3531 if (age
< l
->min_time
)
3533 if (age
> l
->max_time
)
3536 if (track
->pid
< l
->min_pid
)
3537 l
->min_pid
= track
->pid
;
3538 if (track
->pid
> l
->max_pid
)
3539 l
->max_pid
= track
->pid
;
3541 cpu_set(track
->cpu
, l
->cpus
);
3543 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3547 if (track
->addr
< caddr
)
3554 * Not found. Insert new tracking element.
3556 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
3562 (t
->count
- pos
) * sizeof(struct location
));
3565 l
->addr
= track
->addr
;
3569 l
->min_pid
= track
->pid
;
3570 l
->max_pid
= track
->pid
;
3571 cpus_clear(l
->cpus
);
3572 cpu_set(track
->cpu
, l
->cpus
);
3573 nodes_clear(l
->nodes
);
3574 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3578 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
3579 struct page
*page
, enum track_item alloc
)
3581 void *addr
= page_address(page
);
3582 DECLARE_BITMAP(map
, page
->objects
);
3585 bitmap_zero(map
, page
->objects
);
3586 for_each_free_object(p
, s
, page
->freelist
)
3587 set_bit(slab_index(p
, s
, addr
), map
);
3589 for_each_object(p
, s
, addr
, page
->objects
)
3590 if (!test_bit(slab_index(p
, s
, addr
), map
))
3591 add_location(t
, s
, get_track(s
, p
, alloc
));
3594 static int list_locations(struct kmem_cache
*s
, char *buf
,
3595 enum track_item alloc
)
3599 struct loc_track t
= { 0, 0, NULL
};
3602 if (!alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
3604 return sprintf(buf
, "Out of memory\n");
3606 /* Push back cpu slabs */
3609 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3610 struct kmem_cache_node
*n
= get_node(s
, node
);
3611 unsigned long flags
;
3614 if (!atomic_long_read(&n
->nr_slabs
))
3617 spin_lock_irqsave(&n
->list_lock
, flags
);
3618 list_for_each_entry(page
, &n
->partial
, lru
)
3619 process_slab(&t
, s
, page
, alloc
);
3620 list_for_each_entry(page
, &n
->full
, lru
)
3621 process_slab(&t
, s
, page
, alloc
);
3622 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3625 for (i
= 0; i
< t
.count
; i
++) {
3626 struct location
*l
= &t
.loc
[i
];
3628 if (len
> PAGE_SIZE
- 100)
3630 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
3633 len
+= sprint_symbol(buf
+ len
, (unsigned long)l
->addr
);
3635 len
+= sprintf(buf
+ len
, "<not-available>");
3637 if (l
->sum_time
!= l
->min_time
) {
3638 unsigned long remainder
;
3640 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
3642 div_long_long_rem(l
->sum_time
, l
->count
, &remainder
),
3645 len
+= sprintf(buf
+ len
, " age=%ld",
3648 if (l
->min_pid
!= l
->max_pid
)
3649 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
3650 l
->min_pid
, l
->max_pid
);
3652 len
+= sprintf(buf
+ len
, " pid=%ld",
3655 if (num_online_cpus() > 1 && !cpus_empty(l
->cpus
) &&
3656 len
< PAGE_SIZE
- 60) {
3657 len
+= sprintf(buf
+ len
, " cpus=");
3658 len
+= cpulist_scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
3662 if (num_online_nodes() > 1 && !nodes_empty(l
->nodes
) &&
3663 len
< PAGE_SIZE
- 60) {
3664 len
+= sprintf(buf
+ len
, " nodes=");
3665 len
+= nodelist_scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
3669 len
+= sprintf(buf
+ len
, "\n");
3674 len
+= sprintf(buf
, "No data\n");
3678 enum slab_stat_type
{
3685 #define SO_FULL (1 << SL_FULL)
3686 #define SO_PARTIAL (1 << SL_PARTIAL)
3687 #define SO_CPU (1 << SL_CPU)
3688 #define SO_OBJECTS (1 << SL_OBJECTS)
3690 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
3691 char *buf
, unsigned long flags
)
3693 unsigned long total
= 0;
3697 unsigned long *nodes
;
3698 unsigned long *per_cpu
;
3700 nodes
= kzalloc(2 * sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
3703 per_cpu
= nodes
+ nr_node_ids
;
3705 for_each_possible_cpu(cpu
) {
3707 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3717 if (flags
& SO_CPU
) {
3718 if (flags
& SO_OBJECTS
)
3729 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3730 struct kmem_cache_node
*n
= get_node(s
, node
);
3732 if (flags
& SO_PARTIAL
) {
3733 if (flags
& SO_OBJECTS
)
3734 x
= count_partial(n
);
3741 if (flags
& SO_FULL
) {
3742 int full_slabs
= atomic_long_read(&n
->nr_slabs
)
3746 if (flags
& SO_OBJECTS
)
3747 x
= full_slabs
* oo_objects(s
->oo
);
3755 x
= sprintf(buf
, "%lu", total
);
3757 for_each_node_state(node
, N_NORMAL_MEMORY
)
3759 x
+= sprintf(buf
+ x
, " N%d=%lu",
3763 return x
+ sprintf(buf
+ x
, "\n");
3766 static int any_slab_objects(struct kmem_cache
*s
)
3771 for_each_possible_cpu(cpu
) {
3772 struct kmem_cache_cpu
*c
= get_cpu_slab(s
, cpu
);
3778 for_each_online_node(node
) {
3779 struct kmem_cache_node
*n
= get_node(s
, node
);
3784 if (n
->nr_partial
|| atomic_long_read(&n
->nr_slabs
))
3790 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3791 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3793 struct slab_attribute
{
3794 struct attribute attr
;
3795 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
3796 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
3799 #define SLAB_ATTR_RO(_name) \
3800 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3802 #define SLAB_ATTR(_name) \
3803 static struct slab_attribute _name##_attr = \
3804 __ATTR(_name, 0644, _name##_show, _name##_store)
3806 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
3808 return sprintf(buf
, "%d\n", s
->size
);
3810 SLAB_ATTR_RO(slab_size
);
3812 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
3814 return sprintf(buf
, "%d\n", s
->align
);
3816 SLAB_ATTR_RO(align
);
3818 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
3820 return sprintf(buf
, "%d\n", s
->objsize
);
3822 SLAB_ATTR_RO(object_size
);
3824 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
3826 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
3828 SLAB_ATTR_RO(objs_per_slab
);
3830 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
3832 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
3834 SLAB_ATTR_RO(order
);
3836 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
3839 int n
= sprint_symbol(buf
, (unsigned long)s
->ctor
);
3841 return n
+ sprintf(buf
+ n
, "\n");
3847 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
3849 return sprintf(buf
, "%d\n", s
->refcount
- 1);
3851 SLAB_ATTR_RO(aliases
);
3853 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
3855 return show_slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
);
3857 SLAB_ATTR_RO(slabs
);
3859 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
3861 return show_slab_objects(s
, buf
, SO_PARTIAL
);
3863 SLAB_ATTR_RO(partial
);
3865 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
3867 return show_slab_objects(s
, buf
, SO_CPU
);
3869 SLAB_ATTR_RO(cpu_slabs
);
3871 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
3873 return show_slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
|SO_OBJECTS
);
3875 SLAB_ATTR_RO(objects
);
3877 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
3879 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
3882 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
3883 const char *buf
, size_t length
)
3885 s
->flags
&= ~SLAB_DEBUG_FREE
;
3887 s
->flags
|= SLAB_DEBUG_FREE
;
3890 SLAB_ATTR(sanity_checks
);
3892 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
3894 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
3897 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
3900 s
->flags
&= ~SLAB_TRACE
;
3902 s
->flags
|= SLAB_TRACE
;
3907 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
3909 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
3912 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
3913 const char *buf
, size_t length
)
3915 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
3917 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
3920 SLAB_ATTR(reclaim_account
);
3922 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
3924 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
3926 SLAB_ATTR_RO(hwcache_align
);
3928 #ifdef CONFIG_ZONE_DMA
3929 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
3931 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
3933 SLAB_ATTR_RO(cache_dma
);
3936 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
3938 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
3940 SLAB_ATTR_RO(destroy_by_rcu
);
3942 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
3944 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
3947 static ssize_t
red_zone_store(struct kmem_cache
*s
,
3948 const char *buf
, size_t length
)
3950 if (any_slab_objects(s
))
3953 s
->flags
&= ~SLAB_RED_ZONE
;
3955 s
->flags
|= SLAB_RED_ZONE
;
3959 SLAB_ATTR(red_zone
);
3961 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
3963 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
3966 static ssize_t
poison_store(struct kmem_cache
*s
,
3967 const char *buf
, size_t length
)
3969 if (any_slab_objects(s
))
3972 s
->flags
&= ~SLAB_POISON
;
3974 s
->flags
|= SLAB_POISON
;
3980 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
3982 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
3985 static ssize_t
store_user_store(struct kmem_cache
*s
,
3986 const char *buf
, size_t length
)
3988 if (any_slab_objects(s
))
3991 s
->flags
&= ~SLAB_STORE_USER
;
3993 s
->flags
|= SLAB_STORE_USER
;
3997 SLAB_ATTR(store_user
);
3999 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4004 static ssize_t
validate_store(struct kmem_cache
*s
,
4005 const char *buf
, size_t length
)
4009 if (buf
[0] == '1') {
4010 ret
= validate_slab_cache(s
);
4016 SLAB_ATTR(validate
);
4018 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4023 static ssize_t
shrink_store(struct kmem_cache
*s
,
4024 const char *buf
, size_t length
)
4026 if (buf
[0] == '1') {
4027 int rc
= kmem_cache_shrink(s
);
4037 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4039 if (!(s
->flags
& SLAB_STORE_USER
))
4041 return list_locations(s
, buf
, TRACK_ALLOC
);
4043 SLAB_ATTR_RO(alloc_calls
);
4045 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4047 if (!(s
->flags
& SLAB_STORE_USER
))
4049 return list_locations(s
, buf
, TRACK_FREE
);
4051 SLAB_ATTR_RO(free_calls
);
4054 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4056 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4059 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4060 const char *buf
, size_t length
)
4062 int n
= simple_strtoul(buf
, NULL
, 10);
4065 s
->remote_node_defrag_ratio
= n
* 10;
4068 SLAB_ATTR(remote_node_defrag_ratio
);
4071 #ifdef CONFIG_SLUB_STATS
4072 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
4074 unsigned long sum
= 0;
4077 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
4082 for_each_online_cpu(cpu
) {
4083 unsigned x
= get_cpu_slab(s
, cpu
)->stat
[si
];
4089 len
= sprintf(buf
, "%lu", sum
);
4092 for_each_online_cpu(cpu
) {
4093 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
4094 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
4098 return len
+ sprintf(buf
+ len
, "\n");
4101 #define STAT_ATTR(si, text) \
4102 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4104 return show_stat(s, buf, si); \
4106 SLAB_ATTR_RO(text); \
4108 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4109 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
4110 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
4111 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
4112 STAT_ATTR(FREE_FROZEN
, free_frozen
);
4113 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
4114 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
4115 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
4116 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
4117 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
4118 STAT_ATTR(FREE_SLAB
, free_slab
);
4119 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
4120 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
4121 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
4122 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4123 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4124 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4128 static struct attribute
*slab_attrs
[] = {
4129 &slab_size_attr
.attr
,
4130 &object_size_attr
.attr
,
4131 &objs_per_slab_attr
.attr
,
4136 &cpu_slabs_attr
.attr
,
4140 &sanity_checks_attr
.attr
,
4142 &hwcache_align_attr
.attr
,
4143 &reclaim_account_attr
.attr
,
4144 &destroy_by_rcu_attr
.attr
,
4145 &red_zone_attr
.attr
,
4147 &store_user_attr
.attr
,
4148 &validate_attr
.attr
,
4150 &alloc_calls_attr
.attr
,
4151 &free_calls_attr
.attr
,
4152 #ifdef CONFIG_ZONE_DMA
4153 &cache_dma_attr
.attr
,
4156 &remote_node_defrag_ratio_attr
.attr
,
4158 #ifdef CONFIG_SLUB_STATS
4159 &alloc_fastpath_attr
.attr
,
4160 &alloc_slowpath_attr
.attr
,
4161 &free_fastpath_attr
.attr
,
4162 &free_slowpath_attr
.attr
,
4163 &free_frozen_attr
.attr
,
4164 &free_add_partial_attr
.attr
,
4165 &free_remove_partial_attr
.attr
,
4166 &alloc_from_partial_attr
.attr
,
4167 &alloc_slab_attr
.attr
,
4168 &alloc_refill_attr
.attr
,
4169 &free_slab_attr
.attr
,
4170 &cpuslab_flush_attr
.attr
,
4171 &deactivate_full_attr
.attr
,
4172 &deactivate_empty_attr
.attr
,
4173 &deactivate_to_head_attr
.attr
,
4174 &deactivate_to_tail_attr
.attr
,
4175 &deactivate_remote_frees_attr
.attr
,
4180 static struct attribute_group slab_attr_group
= {
4181 .attrs
= slab_attrs
,
4184 static ssize_t
slab_attr_show(struct kobject
*kobj
,
4185 struct attribute
*attr
,
4188 struct slab_attribute
*attribute
;
4189 struct kmem_cache
*s
;
4192 attribute
= to_slab_attr(attr
);
4195 if (!attribute
->show
)
4198 err
= attribute
->show(s
, buf
);
4203 static ssize_t
slab_attr_store(struct kobject
*kobj
,
4204 struct attribute
*attr
,
4205 const char *buf
, size_t len
)
4207 struct slab_attribute
*attribute
;
4208 struct kmem_cache
*s
;
4211 attribute
= to_slab_attr(attr
);
4214 if (!attribute
->store
)
4217 err
= attribute
->store(s
, buf
, len
);
4222 static void kmem_cache_release(struct kobject
*kobj
)
4224 struct kmem_cache
*s
= to_slab(kobj
);
4229 static struct sysfs_ops slab_sysfs_ops
= {
4230 .show
= slab_attr_show
,
4231 .store
= slab_attr_store
,
4234 static struct kobj_type slab_ktype
= {
4235 .sysfs_ops
= &slab_sysfs_ops
,
4236 .release
= kmem_cache_release
4239 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
4241 struct kobj_type
*ktype
= get_ktype(kobj
);
4243 if (ktype
== &slab_ktype
)
4248 static struct kset_uevent_ops slab_uevent_ops
= {
4249 .filter
= uevent_filter
,
4252 static struct kset
*slab_kset
;
4254 #define ID_STR_LENGTH 64
4256 /* Create a unique string id for a slab cache:
4258 * Format :[flags-]size
4260 static char *create_unique_id(struct kmem_cache
*s
)
4262 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
4269 * First flags affecting slabcache operations. We will only
4270 * get here for aliasable slabs so we do not need to support
4271 * too many flags. The flags here must cover all flags that
4272 * are matched during merging to guarantee that the id is
4275 if (s
->flags
& SLAB_CACHE_DMA
)
4277 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
4279 if (s
->flags
& SLAB_DEBUG_FREE
)
4283 p
+= sprintf(p
, "%07d", s
->size
);
4284 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
4288 static int sysfs_slab_add(struct kmem_cache
*s
)
4294 if (slab_state
< SYSFS
)
4295 /* Defer until later */
4298 unmergeable
= slab_unmergeable(s
);
4301 * Slabcache can never be merged so we can use the name proper.
4302 * This is typically the case for debug situations. In that
4303 * case we can catch duplicate names easily.
4305 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
4309 * Create a unique name for the slab as a target
4312 name
= create_unique_id(s
);
4315 s
->kobj
.kset
= slab_kset
;
4316 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, name
);
4318 kobject_put(&s
->kobj
);
4322 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
4325 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
4327 /* Setup first alias */
4328 sysfs_slab_alias(s
, s
->name
);
4334 static void sysfs_slab_remove(struct kmem_cache
*s
)
4336 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
4337 kobject_del(&s
->kobj
);
4338 kobject_put(&s
->kobj
);
4342 * Need to buffer aliases during bootup until sysfs becomes
4343 * available lest we loose that information.
4345 struct saved_alias
{
4346 struct kmem_cache
*s
;
4348 struct saved_alias
*next
;
4351 static struct saved_alias
*alias_list
;
4353 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
4355 struct saved_alias
*al
;
4357 if (slab_state
== SYSFS
) {
4359 * If we have a leftover link then remove it.
4361 sysfs_remove_link(&slab_kset
->kobj
, name
);
4362 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
4365 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
4371 al
->next
= alias_list
;
4376 static int __init
slab_sysfs_init(void)
4378 struct kmem_cache
*s
;
4381 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
4383 printk(KERN_ERR
"Cannot register slab subsystem.\n");
4389 list_for_each_entry(s
, &slab_caches
, list
) {
4390 err
= sysfs_slab_add(s
);
4392 printk(KERN_ERR
"SLUB: Unable to add boot slab %s"
4393 " to sysfs\n", s
->name
);
4396 while (alias_list
) {
4397 struct saved_alias
*al
= alias_list
;
4399 alias_list
= alias_list
->next
;
4400 err
= sysfs_slab_alias(al
->s
, al
->name
);
4402 printk(KERN_ERR
"SLUB: Unable to add boot slab alias"
4403 " %s to sysfs\n", s
->name
);
4411 __initcall(slab_sysfs_init
);
4415 * The /proc/slabinfo ABI
4417 #ifdef CONFIG_SLABINFO
4419 ssize_t
slabinfo_write(struct file
*file
, const char __user
* buffer
,
4420 size_t count
, loff_t
*ppos
)
4426 static void print_slabinfo_header(struct seq_file
*m
)
4428 seq_puts(m
, "slabinfo - version: 2.1\n");
4429 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
4430 "<objperslab> <pagesperslab>");
4431 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
4432 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4436 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
4440 down_read(&slub_lock
);
4442 print_slabinfo_header(m
);
4444 return seq_list_start(&slab_caches
, *pos
);
4447 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
4449 return seq_list_next(p
, &slab_caches
, pos
);
4452 static void s_stop(struct seq_file
*m
, void *p
)
4454 up_read(&slub_lock
);
4457 static int s_show(struct seq_file
*m
, void *p
)
4459 unsigned long nr_partials
= 0;
4460 unsigned long nr_slabs
= 0;
4461 unsigned long nr_inuse
= 0;
4462 unsigned long nr_objs
;
4463 struct kmem_cache
*s
;
4466 s
= list_entry(p
, struct kmem_cache
, list
);
4468 for_each_online_node(node
) {
4469 struct kmem_cache_node
*n
= get_node(s
, node
);
4474 nr_partials
+= n
->nr_partial
;
4475 nr_slabs
+= atomic_long_read(&n
->nr_slabs
);
4476 nr_inuse
+= count_partial(n
);
4479 nr_objs
= nr_slabs
* oo_objects(s
->oo
);
4480 nr_inuse
+= (nr_slabs
- nr_partials
) * oo_objects(s
->oo
);
4482 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d", s
->name
, nr_inuse
,
4483 nr_objs
, s
->size
, oo_objects(s
->oo
),
4484 (1 << oo_order(s
->oo
)));
4485 seq_printf(m
, " : tunables %4u %4u %4u", 0, 0, 0);
4486 seq_printf(m
, " : slabdata %6lu %6lu %6lu", nr_slabs
, nr_slabs
,
4492 const struct seq_operations slabinfo_op
= {
4499 #endif /* CONFIG_SLABINFO */