2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
5 * The allocator synchronizes using per slab locks or atomic operatios
6 * and only uses a centralized lock to manage a pool of partial slabs.
8 * (C) 2007 SGI, Christoph Lameter
9 * (C) 2011 Linux Foundation, Christoph Lameter
13 #include <linux/swap.h> /* struct reclaim_state */
14 #include <linux/module.h>
15 #include <linux/bit_spinlock.h>
16 #include <linux/interrupt.h>
17 #include <linux/bitops.h>
18 #include <linux/slab.h>
19 #include <linux/proc_fs.h>
20 #include <linux/seq_file.h>
21 #include <linux/kmemcheck.h>
22 #include <linux/cpu.h>
23 #include <linux/cpuset.h>
24 #include <linux/mempolicy.h>
25 #include <linux/ctype.h>
26 #include <linux/debugobjects.h>
27 #include <linux/kallsyms.h>
28 #include <linux/memory.h>
29 #include <linux/math64.h>
30 #include <linux/fault-inject.h>
32 #include <trace/events/kmem.h>
36 * 1. slub_lock (Global Semaphore)
38 * 3. slab_lock(page) (Only on some arches and for debugging)
42 * The role of the slub_lock is to protect the list of all the slabs
43 * and to synchronize major metadata changes to slab cache structures.
45 * The slab_lock is only used for debugging and on arches that do not
46 * have the ability to do a cmpxchg_double. It only protects the second
47 * double word in the page struct. Meaning
48 * A. page->freelist -> List of object free in a page
49 * B. page->counters -> Counters of objects
50 * C. page->frozen -> frozen state
52 * If a slab is frozen then it is exempt from list management. It is not
53 * on any list. The processor that froze the slab is the one who can
54 * perform list operations on the page. Other processors may put objects
55 * onto the freelist but the processor that froze the slab is the only
56 * one that can retrieve the objects from the page's freelist.
58 * The list_lock protects the partial and full list on each node and
59 * the partial slab counter. If taken then no new slabs may be added or
60 * removed from the lists nor make the number of partial slabs be modified.
61 * (Note that the total number of slabs is an atomic value that may be
62 * modified without taking the list lock).
64 * The list_lock is a centralized lock and thus we avoid taking it as
65 * much as possible. As long as SLUB does not have to handle partial
66 * slabs, operations can continue without any centralized lock. F.e.
67 * allocating a long series of objects that fill up slabs does not require
69 * Interrupts are disabled during allocation and deallocation in order to
70 * make the slab allocator safe to use in the context of an irq. In addition
71 * interrupts are disabled to ensure that the processor does not change
72 * while handling per_cpu slabs, due to kernel preemption.
74 * SLUB assigns one slab for allocation to each processor.
75 * Allocations only occur from these slabs called cpu slabs.
77 * Slabs with free elements are kept on a partial list and during regular
78 * operations no list for full slabs is used. If an object in a full slab is
79 * freed then the slab will show up again on the partial lists.
80 * We track full slabs for debugging purposes though because otherwise we
81 * cannot scan all objects.
83 * Slabs are freed when they become empty. Teardown and setup is
84 * minimal so we rely on the page allocators per cpu caches for
85 * fast frees and allocs.
87 * Overloading of page flags that are otherwise used for LRU management.
89 * PageActive The slab is frozen and exempt from list processing.
90 * This means that the slab is dedicated to a purpose
91 * such as satisfying allocations for a specific
92 * processor. Objects may be freed in the slab while
93 * it is frozen but slab_free will then skip the usual
94 * list operations. It is up to the processor holding
95 * the slab to integrate the slab into the slab lists
96 * when the slab is no longer needed.
98 * One use of this flag is to mark slabs that are
99 * used for allocations. Then such a slab becomes a cpu
100 * slab. The cpu slab may be equipped with an additional
101 * freelist that allows lockless access to
102 * free objects in addition to the regular freelist
103 * that requires the slab lock.
105 * PageError Slab requires special handling due to debug
106 * options set. This moves slab handling out of
107 * the fast path and disables lockless freelists.
110 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
111 SLAB_TRACE | SLAB_DEBUG_FREE)
113 static inline int kmem_cache_debug(struct kmem_cache
*s
)
115 #ifdef CONFIG_SLUB_DEBUG
116 return unlikely(s
->flags
& SLAB_DEBUG_FLAGS
);
123 * Issues still to be resolved:
125 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
127 * - Variable sizing of the per node arrays
130 /* Enable to test recovery from slab corruption on boot */
131 #undef SLUB_RESILIENCY_TEST
133 /* Enable to log cmpxchg failures */
134 #undef SLUB_DEBUG_CMPXCHG
137 * Mininum number of partial slabs. These will be left on the partial
138 * lists even if they are empty. kmem_cache_shrink may reclaim them.
140 #define MIN_PARTIAL 5
143 * Maximum number of desirable partial slabs.
144 * The existence of more partial slabs makes kmem_cache_shrink
145 * sort the partial list by the number of objects in the.
147 #define MAX_PARTIAL 10
149 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
150 SLAB_POISON | SLAB_STORE_USER)
153 * Debugging flags that require metadata to be stored in the slab. These get
154 * disabled when slub_debug=O is used and a cache's min order increases with
157 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
160 * Set of flags that will prevent slab merging
162 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
163 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
166 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
167 SLAB_CACHE_DMA | SLAB_NOTRACK)
170 #define OO_MASK ((1 << OO_SHIFT) - 1)
171 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
173 /* Internal SLUB flags */
174 #define __OBJECT_POISON 0x80000000UL /* Poison object */
175 #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
177 static int kmem_size
= sizeof(struct kmem_cache
);
180 static struct notifier_block slab_notifier
;
184 DOWN
, /* No slab functionality available */
185 PARTIAL
, /* Kmem_cache_node works */
186 UP
, /* Everything works but does not show up in sysfs */
190 /* A list of all slab caches on the system */
191 static DECLARE_RWSEM(slub_lock
);
192 static LIST_HEAD(slab_caches
);
195 * Tracking user of a slab.
198 unsigned long addr
; /* Called from address */
199 int cpu
; /* Was running on cpu */
200 int pid
; /* Pid context */
201 unsigned long when
; /* When did the operation occur */
204 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
207 static int sysfs_slab_add(struct kmem_cache
*);
208 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
209 static void sysfs_slab_remove(struct kmem_cache
*);
212 static inline int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
213 static inline int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
)
215 static inline void sysfs_slab_remove(struct kmem_cache
*s
)
223 static inline void stat(const struct kmem_cache
*s
, enum stat_item si
)
225 #ifdef CONFIG_SLUB_STATS
226 __this_cpu_inc(s
->cpu_slab
->stat
[si
]);
230 /********************************************************************
231 * Core slab cache functions
232 *******************************************************************/
234 int slab_is_available(void)
236 return slab_state
>= UP
;
239 static inline struct kmem_cache_node
*get_node(struct kmem_cache
*s
, int node
)
241 return s
->node
[node
];
244 /* Verify that a pointer has an address that is valid within a slab page */
245 static inline int check_valid_pointer(struct kmem_cache
*s
,
246 struct page
*page
, const void *object
)
253 base
= page_address(page
);
254 if (object
< base
|| object
>= base
+ page
->objects
* s
->size
||
255 (object
- base
) % s
->size
) {
262 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
264 return *(void **)(object
+ s
->offset
);
267 static inline void *get_freepointer_safe(struct kmem_cache
*s
, void *object
)
271 #ifdef CONFIG_DEBUG_PAGEALLOC
272 probe_kernel_read(&p
, (void **)(object
+ s
->offset
), sizeof(p
));
274 p
= get_freepointer(s
, object
);
279 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
281 *(void **)(object
+ s
->offset
) = fp
;
284 /* Loop over all objects in a slab */
285 #define for_each_object(__p, __s, __addr, __objects) \
286 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
289 /* Determine object index from a given position */
290 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
292 return (p
- addr
) / s
->size
;
295 static inline size_t slab_ksize(const struct kmem_cache
*s
)
297 #ifdef CONFIG_SLUB_DEBUG
299 * Debugging requires use of the padding between object
300 * and whatever may come after it.
302 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
307 * If we have the need to store the freelist pointer
308 * back there or track user information then we can
309 * only use the space before that information.
311 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
314 * Else we can use all the padding etc for the allocation
319 static inline int order_objects(int order
, unsigned long size
, int reserved
)
321 return ((PAGE_SIZE
<< order
) - reserved
) / size
;
324 static inline struct kmem_cache_order_objects
oo_make(int order
,
325 unsigned long size
, int reserved
)
327 struct kmem_cache_order_objects x
= {
328 (order
<< OO_SHIFT
) + order_objects(order
, size
, reserved
)
334 static inline int oo_order(struct kmem_cache_order_objects x
)
336 return x
.x
>> OO_SHIFT
;
339 static inline int oo_objects(struct kmem_cache_order_objects x
)
341 return x
.x
& OO_MASK
;
345 * Per slab locking using the pagelock
347 static __always_inline
void slab_lock(struct page
*page
)
349 bit_spin_lock(PG_locked
, &page
->flags
);
352 static __always_inline
void slab_unlock(struct page
*page
)
354 __bit_spin_unlock(PG_locked
, &page
->flags
);
357 /* Interrupts must be disabled (for the fallback code to work right) */
358 static inline bool __cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
359 void *freelist_old
, unsigned long counters_old
,
360 void *freelist_new
, unsigned long counters_new
,
363 VM_BUG_ON(!irqs_disabled());
364 #ifdef CONFIG_CMPXCHG_DOUBLE
365 if (s
->flags
& __CMPXCHG_DOUBLE
) {
366 if (cmpxchg_double(&page
->freelist
,
367 freelist_old
, counters_old
,
368 freelist_new
, counters_new
))
374 if (page
->freelist
== freelist_old
&& page
->counters
== counters_old
) {
375 page
->freelist
= freelist_new
;
376 page
->counters
= counters_new
;
384 stat(s
, CMPXCHG_DOUBLE_FAIL
);
386 #ifdef SLUB_DEBUG_CMPXCHG
387 printk(KERN_INFO
"%s %s: cmpxchg double redo ", n
, s
->name
);
393 static inline bool cmpxchg_double_slab(struct kmem_cache
*s
, struct page
*page
,
394 void *freelist_old
, unsigned long counters_old
,
395 void *freelist_new
, unsigned long counters_new
,
398 #ifdef CONFIG_CMPXCHG_DOUBLE
399 if (s
->flags
& __CMPXCHG_DOUBLE
) {
400 if (cmpxchg_double(&page
->freelist
,
401 freelist_old
, counters_old
,
402 freelist_new
, counters_new
))
409 local_irq_save(flags
);
411 if (page
->freelist
== freelist_old
&& page
->counters
== counters_old
) {
412 page
->freelist
= freelist_new
;
413 page
->counters
= counters_new
;
415 local_irq_restore(flags
);
419 local_irq_restore(flags
);
423 stat(s
, CMPXCHG_DOUBLE_FAIL
);
425 #ifdef SLUB_DEBUG_CMPXCHG
426 printk(KERN_INFO
"%s %s: cmpxchg double redo ", n
, s
->name
);
432 #ifdef CONFIG_SLUB_DEBUG
434 * Determine a map of object in use on a page.
436 * Node listlock must be held to guarantee that the page does
437 * not vanish from under us.
439 static void get_map(struct kmem_cache
*s
, struct page
*page
, unsigned long *map
)
442 void *addr
= page_address(page
);
444 for (p
= page
->freelist
; p
; p
= get_freepointer(s
, p
))
445 set_bit(slab_index(p
, s
, addr
), map
);
451 #ifdef CONFIG_SLUB_DEBUG_ON
452 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
454 static int slub_debug
;
457 static char *slub_debug_slabs
;
458 static int disable_higher_order_debug
;
463 static void print_section(char *text
, u8
*addr
, unsigned int length
)
471 for (i
= 0; i
< length
; i
++) {
473 printk(KERN_ERR
"%8s 0x%p: ", text
, addr
+ i
);
476 printk(KERN_CONT
" %02x", addr
[i
]);
478 ascii
[offset
] = isgraph(addr
[i
]) ? addr
[i
] : '.';
480 printk(KERN_CONT
" %s\n", ascii
);
487 printk(KERN_CONT
" ");
491 printk(KERN_CONT
" %s\n", ascii
);
495 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
496 enum track_item alloc
)
501 p
= object
+ s
->offset
+ sizeof(void *);
503 p
= object
+ s
->inuse
;
508 static void set_track(struct kmem_cache
*s
, void *object
,
509 enum track_item alloc
, unsigned long addr
)
511 struct track
*p
= get_track(s
, object
, alloc
);
515 p
->cpu
= smp_processor_id();
516 p
->pid
= current
->pid
;
519 memset(p
, 0, sizeof(struct track
));
522 static void init_tracking(struct kmem_cache
*s
, void *object
)
524 if (!(s
->flags
& SLAB_STORE_USER
))
527 set_track(s
, object
, TRACK_FREE
, 0UL);
528 set_track(s
, object
, TRACK_ALLOC
, 0UL);
531 static void print_track(const char *s
, struct track
*t
)
536 printk(KERN_ERR
"INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
537 s
, (void *)t
->addr
, jiffies
- t
->when
, t
->cpu
, t
->pid
);
540 static void print_tracking(struct kmem_cache
*s
, void *object
)
542 if (!(s
->flags
& SLAB_STORE_USER
))
545 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
546 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
549 static void print_page_info(struct page
*page
)
551 printk(KERN_ERR
"INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
552 page
, page
->objects
, page
->inuse
, page
->freelist
, page
->flags
);
556 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
562 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
564 printk(KERN_ERR
"========================================"
565 "=====================================\n");
566 printk(KERN_ERR
"BUG %s: %s\n", s
->name
, buf
);
567 printk(KERN_ERR
"----------------------------------------"
568 "-------------------------------------\n\n");
571 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
577 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
579 printk(KERN_ERR
"FIX %s: %s\n", s
->name
, buf
);
582 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
584 unsigned int off
; /* Offset of last byte */
585 u8
*addr
= page_address(page
);
587 print_tracking(s
, p
);
589 print_page_info(page
);
591 printk(KERN_ERR
"INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
592 p
, p
- addr
, get_freepointer(s
, p
));
595 print_section("Bytes b4", p
- 16, 16);
597 print_section("Object", p
, min_t(unsigned long, s
->objsize
, PAGE_SIZE
));
599 if (s
->flags
& SLAB_RED_ZONE
)
600 print_section("Redzone", p
+ s
->objsize
,
601 s
->inuse
- s
->objsize
);
604 off
= s
->offset
+ sizeof(void *);
608 if (s
->flags
& SLAB_STORE_USER
)
609 off
+= 2 * sizeof(struct track
);
612 /* Beginning of the filler is the free pointer */
613 print_section("Padding", p
+ off
, s
->size
- off
);
618 static void object_err(struct kmem_cache
*s
, struct page
*page
,
619 u8
*object
, char *reason
)
621 slab_bug(s
, "%s", reason
);
622 print_trailer(s
, page
, object
);
625 static void slab_err(struct kmem_cache
*s
, struct page
*page
, char *fmt
, ...)
631 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
633 slab_bug(s
, "%s", buf
);
634 print_page_info(page
);
638 static void init_object(struct kmem_cache
*s
, void *object
, u8 val
)
642 if (s
->flags
& __OBJECT_POISON
) {
643 memset(p
, POISON_FREE
, s
->objsize
- 1);
644 p
[s
->objsize
- 1] = POISON_END
;
647 if (s
->flags
& SLAB_RED_ZONE
)
648 memset(p
+ s
->objsize
, val
, s
->inuse
- s
->objsize
);
651 static u8
*check_bytes(u8
*start
, unsigned int value
, unsigned int bytes
)
654 if (*start
!= (u8
)value
)
662 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
663 void *from
, void *to
)
665 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
666 memset(from
, data
, to
- from
);
669 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
670 u8
*object
, char *what
,
671 u8
*start
, unsigned int value
, unsigned int bytes
)
676 fault
= check_bytes(start
, value
, bytes
);
681 while (end
> fault
&& end
[-1] == value
)
684 slab_bug(s
, "%s overwritten", what
);
685 printk(KERN_ERR
"INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
686 fault
, end
- 1, fault
[0], value
);
687 print_trailer(s
, page
, object
);
689 restore_bytes(s
, what
, value
, fault
, end
);
697 * Bytes of the object to be managed.
698 * If the freepointer may overlay the object then the free
699 * pointer is the first word of the object.
701 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
704 * object + s->objsize
705 * Padding to reach word boundary. This is also used for Redzoning.
706 * Padding is extended by another word if Redzoning is enabled and
709 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
710 * 0xcc (RED_ACTIVE) for objects in use.
713 * Meta data starts here.
715 * A. Free pointer (if we cannot overwrite object on free)
716 * B. Tracking data for SLAB_STORE_USER
717 * C. Padding to reach required alignment boundary or at mininum
718 * one word if debugging is on to be able to detect writes
719 * before the word boundary.
721 * Padding is done using 0x5a (POISON_INUSE)
724 * Nothing is used beyond s->size.
726 * If slabcaches are merged then the objsize and inuse boundaries are mostly
727 * ignored. And therefore no slab options that rely on these boundaries
728 * may be used with merged slabcaches.
731 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
733 unsigned long off
= s
->inuse
; /* The end of info */
736 /* Freepointer is placed after the object. */
737 off
+= sizeof(void *);
739 if (s
->flags
& SLAB_STORE_USER
)
740 /* We also have user information there */
741 off
+= 2 * sizeof(struct track
);
746 return check_bytes_and_report(s
, page
, p
, "Object padding",
747 p
+ off
, POISON_INUSE
, s
->size
- off
);
750 /* Check the pad bytes at the end of a slab page */
751 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
759 if (!(s
->flags
& SLAB_POISON
))
762 start
= page_address(page
);
763 length
= (PAGE_SIZE
<< compound_order(page
)) - s
->reserved
;
764 end
= start
+ length
;
765 remainder
= length
% s
->size
;
769 fault
= check_bytes(end
- remainder
, POISON_INUSE
, remainder
);
772 while (end
> fault
&& end
[-1] == POISON_INUSE
)
775 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
776 print_section("Padding", end
- remainder
, remainder
);
778 restore_bytes(s
, "slab padding", POISON_INUSE
, end
- remainder
, end
);
782 static int check_object(struct kmem_cache
*s
, struct page
*page
,
783 void *object
, u8 val
)
786 u8
*endobject
= object
+ s
->objsize
;
788 if (s
->flags
& SLAB_RED_ZONE
) {
789 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
790 endobject
, val
, s
->inuse
- s
->objsize
))
793 if ((s
->flags
& SLAB_POISON
) && s
->objsize
< s
->inuse
) {
794 check_bytes_and_report(s
, page
, p
, "Alignment padding",
795 endobject
, POISON_INUSE
, s
->inuse
- s
->objsize
);
799 if (s
->flags
& SLAB_POISON
) {
800 if (val
!= SLUB_RED_ACTIVE
&& (s
->flags
& __OBJECT_POISON
) &&
801 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
802 POISON_FREE
, s
->objsize
- 1) ||
803 !check_bytes_and_report(s
, page
, p
, "Poison",
804 p
+ s
->objsize
- 1, POISON_END
, 1)))
807 * check_pad_bytes cleans up on its own.
809 check_pad_bytes(s
, page
, p
);
812 if (!s
->offset
&& val
== SLUB_RED_ACTIVE
)
814 * Object and freepointer overlap. Cannot check
815 * freepointer while object is allocated.
819 /* Check free pointer validity */
820 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
821 object_err(s
, page
, p
, "Freepointer corrupt");
823 * No choice but to zap it and thus lose the remainder
824 * of the free objects in this slab. May cause
825 * another error because the object count is now wrong.
827 set_freepointer(s
, p
, NULL
);
833 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
837 VM_BUG_ON(!irqs_disabled());
839 if (!PageSlab(page
)) {
840 slab_err(s
, page
, "Not a valid slab page");
844 maxobj
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
845 if (page
->objects
> maxobj
) {
846 slab_err(s
, page
, "objects %u > max %u",
847 s
->name
, page
->objects
, maxobj
);
850 if (page
->inuse
> page
->objects
) {
851 slab_err(s
, page
, "inuse %u > max %u",
852 s
->name
, page
->inuse
, page
->objects
);
855 /* Slab_pad_check fixes things up after itself */
856 slab_pad_check(s
, page
);
861 * Determine if a certain object on a page is on the freelist. Must hold the
862 * slab lock to guarantee that the chains are in a consistent state.
864 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
869 unsigned long max_objects
;
872 while (fp
&& nr
<= page
->objects
) {
875 if (!check_valid_pointer(s
, page
, fp
)) {
877 object_err(s
, page
, object
,
878 "Freechain corrupt");
879 set_freepointer(s
, object
, NULL
);
882 slab_err(s
, page
, "Freepointer corrupt");
883 page
->freelist
= NULL
;
884 page
->inuse
= page
->objects
;
885 slab_fix(s
, "Freelist cleared");
891 fp
= get_freepointer(s
, object
);
895 max_objects
= order_objects(compound_order(page
), s
->size
, s
->reserved
);
896 if (max_objects
> MAX_OBJS_PER_PAGE
)
897 max_objects
= MAX_OBJS_PER_PAGE
;
899 if (page
->objects
!= max_objects
) {
900 slab_err(s
, page
, "Wrong number of objects. Found %d but "
901 "should be %d", page
->objects
, max_objects
);
902 page
->objects
= max_objects
;
903 slab_fix(s
, "Number of objects adjusted.");
905 if (page
->inuse
!= page
->objects
- nr
) {
906 slab_err(s
, page
, "Wrong object count. Counter is %d but "
907 "counted were %d", page
->inuse
, page
->objects
- nr
);
908 page
->inuse
= page
->objects
- nr
;
909 slab_fix(s
, "Object count adjusted.");
911 return search
== NULL
;
914 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
,
917 if (s
->flags
& SLAB_TRACE
) {
918 printk(KERN_INFO
"TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
920 alloc
? "alloc" : "free",
925 print_section("Object", (void *)object
, s
->objsize
);
932 * Hooks for other subsystems that check memory allocations. In a typical
933 * production configuration these hooks all should produce no code at all.
935 static inline int slab_pre_alloc_hook(struct kmem_cache
*s
, gfp_t flags
)
937 flags
&= gfp_allowed_mask
;
938 lockdep_trace_alloc(flags
);
939 might_sleep_if(flags
& __GFP_WAIT
);
941 return should_failslab(s
->objsize
, flags
, s
->flags
);
944 static inline void slab_post_alloc_hook(struct kmem_cache
*s
, gfp_t flags
, void *object
)
946 flags
&= gfp_allowed_mask
;
947 kmemcheck_slab_alloc(s
, flags
, object
, slab_ksize(s
));
948 kmemleak_alloc_recursive(object
, s
->objsize
, 1, s
->flags
, flags
);
951 static inline void slab_free_hook(struct kmem_cache
*s
, void *x
)
953 kmemleak_free_recursive(x
, s
->flags
);
956 * Trouble is that we may no longer disable interupts in the fast path
957 * So in order to make the debug calls that expect irqs to be
958 * disabled we need to disable interrupts temporarily.
960 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
964 local_irq_save(flags
);
965 kmemcheck_slab_free(s
, x
, s
->objsize
);
966 debug_check_no_locks_freed(x
, s
->objsize
);
967 local_irq_restore(flags
);
970 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
971 debug_check_no_obj_freed(x
, s
->objsize
);
975 * Tracking of fully allocated slabs for debugging purposes.
977 * list_lock must be held.
979 static void add_full(struct kmem_cache
*s
,
980 struct kmem_cache_node
*n
, struct page
*page
)
982 if (!(s
->flags
& SLAB_STORE_USER
))
985 list_add(&page
->lru
, &n
->full
);
989 * list_lock must be held.
991 static void remove_full(struct kmem_cache
*s
, struct page
*page
)
993 if (!(s
->flags
& SLAB_STORE_USER
))
996 list_del(&page
->lru
);
999 /* Tracking of the number of slabs for debugging purposes */
1000 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1002 struct kmem_cache_node
*n
= get_node(s
, node
);
1004 return atomic_long_read(&n
->nr_slabs
);
1007 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1009 return atomic_long_read(&n
->nr_slabs
);
1012 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1014 struct kmem_cache_node
*n
= get_node(s
, node
);
1017 * May be called early in order to allocate a slab for the
1018 * kmem_cache_node structure. Solve the chicken-egg
1019 * dilemma by deferring the increment of the count during
1020 * bootstrap (see early_kmem_cache_node_alloc).
1023 atomic_long_inc(&n
->nr_slabs
);
1024 atomic_long_add(objects
, &n
->total_objects
);
1027 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
, int objects
)
1029 struct kmem_cache_node
*n
= get_node(s
, node
);
1031 atomic_long_dec(&n
->nr_slabs
);
1032 atomic_long_sub(objects
, &n
->total_objects
);
1035 /* Object debug checks for alloc/free paths */
1036 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
1039 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
1042 init_object(s
, object
, SLUB_RED_INACTIVE
);
1043 init_tracking(s
, object
);
1046 static noinline
int alloc_debug_processing(struct kmem_cache
*s
, struct page
*page
,
1047 void *object
, unsigned long addr
)
1049 if (!check_slab(s
, page
))
1052 if (!check_valid_pointer(s
, page
, object
)) {
1053 object_err(s
, page
, object
, "Freelist Pointer check fails");
1057 if (!check_object(s
, page
, object
, SLUB_RED_INACTIVE
))
1060 /* Success perform special debug activities for allocs */
1061 if (s
->flags
& SLAB_STORE_USER
)
1062 set_track(s
, object
, TRACK_ALLOC
, addr
);
1063 trace(s
, page
, object
, 1);
1064 init_object(s
, object
, SLUB_RED_ACTIVE
);
1068 if (PageSlab(page
)) {
1070 * If this is a slab page then lets do the best we can
1071 * to avoid issues in the future. Marking all objects
1072 * as used avoids touching the remaining objects.
1074 slab_fix(s
, "Marking all objects used");
1075 page
->inuse
= page
->objects
;
1076 page
->freelist
= NULL
;
1081 static noinline
int free_debug_processing(struct kmem_cache
*s
,
1082 struct page
*page
, void *object
, unsigned long addr
)
1084 unsigned long flags
;
1087 local_irq_save(flags
);
1090 if (!check_slab(s
, page
))
1093 if (!check_valid_pointer(s
, page
, object
)) {
1094 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
1098 if (on_freelist(s
, page
, object
)) {
1099 object_err(s
, page
, object
, "Object already free");
1103 if (!check_object(s
, page
, object
, SLUB_RED_ACTIVE
))
1106 if (unlikely(s
!= page
->slab
)) {
1107 if (!PageSlab(page
)) {
1108 slab_err(s
, page
, "Attempt to free object(0x%p) "
1109 "outside of slab", object
);
1110 } else if (!page
->slab
) {
1112 "SLUB <none>: no slab for object 0x%p.\n",
1116 object_err(s
, page
, object
,
1117 "page slab pointer corrupt.");
1121 if (s
->flags
& SLAB_STORE_USER
)
1122 set_track(s
, object
, TRACK_FREE
, addr
);
1123 trace(s
, page
, object
, 0);
1124 init_object(s
, object
, SLUB_RED_INACTIVE
);
1128 local_irq_restore(flags
);
1132 slab_fix(s
, "Object at 0x%p not freed", object
);
1136 static int __init
setup_slub_debug(char *str
)
1138 slub_debug
= DEBUG_DEFAULT_FLAGS
;
1139 if (*str
++ != '=' || !*str
)
1141 * No options specified. Switch on full debugging.
1147 * No options but restriction on slabs. This means full
1148 * debugging for slabs matching a pattern.
1152 if (tolower(*str
) == 'o') {
1154 * Avoid enabling debugging on caches if its minimum order
1155 * would increase as a result.
1157 disable_higher_order_debug
= 1;
1164 * Switch off all debugging measures.
1169 * Determine which debug features should be switched on
1171 for (; *str
&& *str
!= ','; str
++) {
1172 switch (tolower(*str
)) {
1174 slub_debug
|= SLAB_DEBUG_FREE
;
1177 slub_debug
|= SLAB_RED_ZONE
;
1180 slub_debug
|= SLAB_POISON
;
1183 slub_debug
|= SLAB_STORE_USER
;
1186 slub_debug
|= SLAB_TRACE
;
1189 slub_debug
|= SLAB_FAILSLAB
;
1192 printk(KERN_ERR
"slub_debug option '%c' "
1193 "unknown. skipped\n", *str
);
1199 slub_debug_slabs
= str
+ 1;
1204 __setup("slub_debug", setup_slub_debug
);
1206 static unsigned long kmem_cache_flags(unsigned long objsize
,
1207 unsigned long flags
, const char *name
,
1208 void (*ctor
)(void *))
1211 * Enable debugging if selected on the kernel commandline.
1213 if (slub_debug
&& (!slub_debug_slabs
||
1214 !strncmp(slub_debug_slabs
, name
, strlen(slub_debug_slabs
))))
1215 flags
|= slub_debug
;
1220 static inline void setup_object_debug(struct kmem_cache
*s
,
1221 struct page
*page
, void *object
) {}
1223 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1224 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1226 static inline int free_debug_processing(struct kmem_cache
*s
,
1227 struct page
*page
, void *object
, unsigned long addr
) { return 0; }
1229 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1231 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1232 void *object
, u8 val
) { return 1; }
1233 static inline void add_full(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
1234 struct page
*page
) {}
1235 static inline void remove_full(struct kmem_cache
*s
, struct page
*page
) {}
1236 static inline unsigned long kmem_cache_flags(unsigned long objsize
,
1237 unsigned long flags
, const char *name
,
1238 void (*ctor
)(void *))
1242 #define slub_debug 0
1244 #define disable_higher_order_debug 0
1246 static inline unsigned long slabs_node(struct kmem_cache
*s
, int node
)
1248 static inline unsigned long node_nr_slabs(struct kmem_cache_node
*n
)
1250 static inline void inc_slabs_node(struct kmem_cache
*s
, int node
,
1252 static inline void dec_slabs_node(struct kmem_cache
*s
, int node
,
1255 static inline int slab_pre_alloc_hook(struct kmem_cache
*s
, gfp_t flags
)
1258 static inline void slab_post_alloc_hook(struct kmem_cache
*s
, gfp_t flags
,
1261 static inline void slab_free_hook(struct kmem_cache
*s
, void *x
) {}
1263 #endif /* CONFIG_SLUB_DEBUG */
1266 * Slab allocation and freeing
1268 static inline struct page
*alloc_slab_page(gfp_t flags
, int node
,
1269 struct kmem_cache_order_objects oo
)
1271 int order
= oo_order(oo
);
1273 flags
|= __GFP_NOTRACK
;
1275 if (node
== NUMA_NO_NODE
)
1276 return alloc_pages(flags
, order
);
1278 return alloc_pages_exact_node(node
, flags
, order
);
1281 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1284 struct kmem_cache_order_objects oo
= s
->oo
;
1287 flags
&= gfp_allowed_mask
;
1289 if (flags
& __GFP_WAIT
)
1292 flags
|= s
->allocflags
;
1295 * Let the initial higher-order allocation fail under memory pressure
1296 * so we fall-back to the minimum order allocation.
1298 alloc_gfp
= (flags
| __GFP_NOWARN
| __GFP_NORETRY
) & ~__GFP_NOFAIL
;
1300 page
= alloc_slab_page(alloc_gfp
, node
, oo
);
1301 if (unlikely(!page
)) {
1304 * Allocation may have failed due to fragmentation.
1305 * Try a lower order alloc if possible
1307 page
= alloc_slab_page(flags
, node
, oo
);
1310 stat(s
, ORDER_FALLBACK
);
1313 if (flags
& __GFP_WAIT
)
1314 local_irq_disable();
1319 if (kmemcheck_enabled
1320 && !(s
->flags
& (SLAB_NOTRACK
| DEBUG_DEFAULT_FLAGS
))) {
1321 int pages
= 1 << oo_order(oo
);
1323 kmemcheck_alloc_shadow(page
, oo_order(oo
), flags
, node
);
1326 * Objects from caches that have a constructor don't get
1327 * cleared when they're allocated, so we need to do it here.
1330 kmemcheck_mark_uninitialized_pages(page
, pages
);
1332 kmemcheck_mark_unallocated_pages(page
, pages
);
1335 page
->objects
= oo_objects(oo
);
1336 mod_zone_page_state(page_zone(page
),
1337 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1338 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1344 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1347 setup_object_debug(s
, page
, object
);
1348 if (unlikely(s
->ctor
))
1352 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1359 BUG_ON(flags
& GFP_SLAB_BUG_MASK
);
1361 page
= allocate_slab(s
,
1362 flags
& (GFP_RECLAIM_MASK
| GFP_CONSTRAINT_MASK
), node
);
1366 inc_slabs_node(s
, page_to_nid(page
), page
->objects
);
1368 page
->flags
|= 1 << PG_slab
;
1370 start
= page_address(page
);
1372 if (unlikely(s
->flags
& SLAB_POISON
))
1373 memset(start
, POISON_INUSE
, PAGE_SIZE
<< compound_order(page
));
1376 for_each_object(p
, s
, start
, page
->objects
) {
1377 setup_object(s
, page
, last
);
1378 set_freepointer(s
, last
, p
);
1381 setup_object(s
, page
, last
);
1382 set_freepointer(s
, last
, NULL
);
1384 page
->freelist
= start
;
1391 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1393 int order
= compound_order(page
);
1394 int pages
= 1 << order
;
1396 if (kmem_cache_debug(s
)) {
1399 slab_pad_check(s
, page
);
1400 for_each_object(p
, s
, page_address(page
),
1402 check_object(s
, page
, p
, SLUB_RED_INACTIVE
);
1405 kmemcheck_free_shadow(page
, compound_order(page
));
1407 mod_zone_page_state(page_zone(page
),
1408 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1409 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1412 __ClearPageSlab(page
);
1413 reset_page_mapcount(page
);
1414 if (current
->reclaim_state
)
1415 current
->reclaim_state
->reclaimed_slab
+= pages
;
1416 __free_pages(page
, order
);
1419 #define need_reserve_slab_rcu \
1420 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1422 static void rcu_free_slab(struct rcu_head
*h
)
1426 if (need_reserve_slab_rcu
)
1427 page
= virt_to_head_page(h
);
1429 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1431 __free_slab(page
->slab
, page
);
1434 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1436 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1437 struct rcu_head
*head
;
1439 if (need_reserve_slab_rcu
) {
1440 int order
= compound_order(page
);
1441 int offset
= (PAGE_SIZE
<< order
) - s
->reserved
;
1443 VM_BUG_ON(s
->reserved
!= sizeof(*head
));
1444 head
= page_address(page
) + offset
;
1447 * RCU free overloads the RCU head over the LRU
1449 head
= (void *)&page
->lru
;
1452 call_rcu(head
, rcu_free_slab
);
1454 __free_slab(s
, page
);
1457 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1459 dec_slabs_node(s
, page_to_nid(page
), page
->objects
);
1464 * Management of partially allocated slabs.
1466 * list_lock must be held.
1468 static inline void add_partial(struct kmem_cache_node
*n
,
1469 struct page
*page
, int tail
)
1473 list_add_tail(&page
->lru
, &n
->partial
);
1475 list_add(&page
->lru
, &n
->partial
);
1479 * list_lock must be held.
1481 static inline void remove_partial(struct kmem_cache_node
*n
,
1484 list_del(&page
->lru
);
1489 * Lock slab, remove from the partial list and put the object into the
1492 * Must hold list_lock.
1494 static inline int acquire_slab(struct kmem_cache
*s
,
1495 struct kmem_cache_node
*n
, struct page
*page
)
1498 unsigned long counters
;
1502 * Zap the freelist and set the frozen bit.
1503 * The old freelist is the list of objects for the
1504 * per cpu allocation list.
1507 freelist
= page
->freelist
;
1508 counters
= page
->counters
;
1509 new.counters
= counters
;
1510 new.inuse
= page
->objects
;
1512 VM_BUG_ON(new.frozen
);
1515 } while (!__cmpxchg_double_slab(s
, page
,
1518 "lock and freeze"));
1520 remove_partial(n
, page
);
1523 /* Populate the per cpu freelist */
1524 this_cpu_write(s
->cpu_slab
->freelist
, freelist
);
1525 this_cpu_write(s
->cpu_slab
->page
, page
);
1526 this_cpu_write(s
->cpu_slab
->node
, page_to_nid(page
));
1530 * Slab page came from the wrong list. No object to allocate
1531 * from. Put it onto the correct list and continue partial
1534 printk(KERN_ERR
"SLUB: %s : Page without available objects on"
1535 " partial list\n", s
->name
);
1541 * Try to allocate a partial slab from a specific node.
1543 static struct page
*get_partial_node(struct kmem_cache
*s
,
1544 struct kmem_cache_node
*n
)
1549 * Racy check. If we mistakenly see no partial slabs then we
1550 * just allocate an empty slab. If we mistakenly try to get a
1551 * partial slab and there is none available then get_partials()
1554 if (!n
|| !n
->nr_partial
)
1557 spin_lock(&n
->list_lock
);
1558 list_for_each_entry(page
, &n
->partial
, lru
)
1559 if (acquire_slab(s
, n
, page
))
1563 spin_unlock(&n
->list_lock
);
1568 * Get a page from somewhere. Search in increasing NUMA distances.
1570 static struct page
*get_any_partial(struct kmem_cache
*s
, gfp_t flags
)
1573 struct zonelist
*zonelist
;
1576 enum zone_type high_zoneidx
= gfp_zone(flags
);
1580 * The defrag ratio allows a configuration of the tradeoffs between
1581 * inter node defragmentation and node local allocations. A lower
1582 * defrag_ratio increases the tendency to do local allocations
1583 * instead of attempting to obtain partial slabs from other nodes.
1585 * If the defrag_ratio is set to 0 then kmalloc() always
1586 * returns node local objects. If the ratio is higher then kmalloc()
1587 * may return off node objects because partial slabs are obtained
1588 * from other nodes and filled up.
1590 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1591 * defrag_ratio = 1000) then every (well almost) allocation will
1592 * first attempt to defrag slab caches on other nodes. This means
1593 * scanning over all nodes to look for partial slabs which may be
1594 * expensive if we do it every time we are trying to find a slab
1595 * with available objects.
1597 if (!s
->remote_node_defrag_ratio
||
1598 get_cycles() % 1024 > s
->remote_node_defrag_ratio
)
1602 zonelist
= node_zonelist(slab_node(current
->mempolicy
), flags
);
1603 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
1604 struct kmem_cache_node
*n
;
1606 n
= get_node(s
, zone_to_nid(zone
));
1608 if (n
&& cpuset_zone_allowed_hardwall(zone
, flags
) &&
1609 n
->nr_partial
> s
->min_partial
) {
1610 page
= get_partial_node(s
, n
);
1623 * Get a partial page, lock it and return it.
1625 static struct page
*get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
)
1628 int searchnode
= (node
== NUMA_NO_NODE
) ? numa_node_id() : node
;
1630 page
= get_partial_node(s
, get_node(s
, searchnode
));
1631 if (page
|| node
!= NUMA_NO_NODE
)
1634 return get_any_partial(s
, flags
);
1637 #ifdef CONFIG_PREEMPT
1639 * Calculate the next globally unique transaction for disambiguiation
1640 * during cmpxchg. The transactions start with the cpu number and are then
1641 * incremented by CONFIG_NR_CPUS.
1643 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1646 * No preemption supported therefore also no need to check for
1652 static inline unsigned long next_tid(unsigned long tid
)
1654 return tid
+ TID_STEP
;
1657 static inline unsigned int tid_to_cpu(unsigned long tid
)
1659 return tid
% TID_STEP
;
1662 static inline unsigned long tid_to_event(unsigned long tid
)
1664 return tid
/ TID_STEP
;
1667 static inline unsigned int init_tid(int cpu
)
1672 static inline void note_cmpxchg_failure(const char *n
,
1673 const struct kmem_cache
*s
, unsigned long tid
)
1675 #ifdef SLUB_DEBUG_CMPXCHG
1676 unsigned long actual_tid
= __this_cpu_read(s
->cpu_slab
->tid
);
1678 printk(KERN_INFO
"%s %s: cmpxchg redo ", n
, s
->name
);
1680 #ifdef CONFIG_PREEMPT
1681 if (tid_to_cpu(tid
) != tid_to_cpu(actual_tid
))
1682 printk("due to cpu change %d -> %d\n",
1683 tid_to_cpu(tid
), tid_to_cpu(actual_tid
));
1686 if (tid_to_event(tid
) != tid_to_event(actual_tid
))
1687 printk("due to cpu running other code. Event %ld->%ld\n",
1688 tid_to_event(tid
), tid_to_event(actual_tid
));
1690 printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1691 actual_tid
, tid
, next_tid(tid
));
1693 stat(s
, CMPXCHG_DOUBLE_CPU_FAIL
);
1696 void init_kmem_cache_cpus(struct kmem_cache
*s
)
1700 for_each_possible_cpu(cpu
)
1701 per_cpu_ptr(s
->cpu_slab
, cpu
)->tid
= init_tid(cpu
);
1704 * Remove the cpu slab
1708 * Remove the cpu slab
1710 static void deactivate_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1712 enum slab_modes
{ M_NONE
, M_PARTIAL
, M_FULL
, M_FREE
};
1713 struct page
*page
= c
->page
;
1714 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1716 enum slab_modes l
= M_NONE
, m
= M_NONE
;
1723 if (page
->freelist
) {
1724 stat(s
, DEACTIVATE_REMOTE_FREES
);
1728 c
->tid
= next_tid(c
->tid
);
1730 freelist
= c
->freelist
;
1734 * Stage one: Free all available per cpu objects back
1735 * to the page freelist while it is still frozen. Leave the
1738 * There is no need to take the list->lock because the page
1741 while (freelist
&& (nextfree
= get_freepointer(s
, freelist
))) {
1743 unsigned long counters
;
1746 prior
= page
->freelist
;
1747 counters
= page
->counters
;
1748 set_freepointer(s
, freelist
, prior
);
1749 new.counters
= counters
;
1751 VM_BUG_ON(!new.frozen
);
1753 } while (!__cmpxchg_double_slab(s
, page
,
1755 freelist
, new.counters
,
1756 "drain percpu freelist"));
1758 freelist
= nextfree
;
1762 * Stage two: Ensure that the page is unfrozen while the
1763 * list presence reflects the actual number of objects
1766 * We setup the list membership and then perform a cmpxchg
1767 * with the count. If there is a mismatch then the page
1768 * is not unfrozen but the page is on the wrong list.
1770 * Then we restart the process which may have to remove
1771 * the page from the list that we just put it on again
1772 * because the number of objects in the slab may have
1777 old
.freelist
= page
->freelist
;
1778 old
.counters
= page
->counters
;
1779 VM_BUG_ON(!old
.frozen
);
1781 /* Determine target state of the slab */
1782 new.counters
= old
.counters
;
1785 set_freepointer(s
, freelist
, old
.freelist
);
1786 new.freelist
= freelist
;
1788 new.freelist
= old
.freelist
;
1792 if (!new.inuse
&& n
->nr_partial
< s
->min_partial
)
1794 else if (new.freelist
) {
1799 * Taking the spinlock removes the possiblity
1800 * that acquire_slab() will see a slab page that
1803 spin_lock(&n
->list_lock
);
1807 if (kmem_cache_debug(s
) && !lock
) {
1810 * This also ensures that the scanning of full
1811 * slabs from diagnostic functions will not see
1814 spin_lock(&n
->list_lock
);
1822 remove_partial(n
, page
);
1824 else if (l
== M_FULL
)
1826 remove_full(s
, page
);
1828 if (m
== M_PARTIAL
) {
1830 add_partial(n
, page
, tail
);
1831 stat(s
, tail
? DEACTIVATE_TO_TAIL
: DEACTIVATE_TO_HEAD
);
1833 } else if (m
== M_FULL
) {
1835 stat(s
, DEACTIVATE_FULL
);
1836 add_full(s
, n
, page
);
1842 if (!__cmpxchg_double_slab(s
, page
,
1843 old
.freelist
, old
.counters
,
1844 new.freelist
, new.counters
,
1849 spin_unlock(&n
->list_lock
);
1852 stat(s
, DEACTIVATE_EMPTY
);
1853 discard_slab(s
, page
);
1858 static inline void flush_slab(struct kmem_cache
*s
, struct kmem_cache_cpu
*c
)
1860 stat(s
, CPUSLAB_FLUSH
);
1861 deactivate_slab(s
, c
);
1867 * Called from IPI handler with interrupts disabled.
1869 static inline void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
1871 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
1873 if (likely(c
&& c
->page
))
1877 static void flush_cpu_slab(void *d
)
1879 struct kmem_cache
*s
= d
;
1881 __flush_cpu_slab(s
, smp_processor_id());
1884 static void flush_all(struct kmem_cache
*s
)
1886 on_each_cpu(flush_cpu_slab
, s
, 1);
1890 * Check if the objects in a per cpu structure fit numa
1891 * locality expectations.
1893 static inline int node_match(struct kmem_cache_cpu
*c
, int node
)
1896 if (node
!= NUMA_NO_NODE
&& c
->node
!= node
)
1902 static int count_free(struct page
*page
)
1904 return page
->objects
- page
->inuse
;
1907 static unsigned long count_partial(struct kmem_cache_node
*n
,
1908 int (*get_count
)(struct page
*))
1910 unsigned long flags
;
1911 unsigned long x
= 0;
1914 spin_lock_irqsave(&n
->list_lock
, flags
);
1915 list_for_each_entry(page
, &n
->partial
, lru
)
1916 x
+= get_count(page
);
1917 spin_unlock_irqrestore(&n
->list_lock
, flags
);
1921 static inline unsigned long node_nr_objs(struct kmem_cache_node
*n
)
1923 #ifdef CONFIG_SLUB_DEBUG
1924 return atomic_long_read(&n
->total_objects
);
1930 static noinline
void
1931 slab_out_of_memory(struct kmem_cache
*s
, gfp_t gfpflags
, int nid
)
1936 "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1938 printk(KERN_WARNING
" cache: %s, object size: %d, buffer size: %d, "
1939 "default order: %d, min order: %d\n", s
->name
, s
->objsize
,
1940 s
->size
, oo_order(s
->oo
), oo_order(s
->min
));
1942 if (oo_order(s
->min
) > get_order(s
->objsize
))
1943 printk(KERN_WARNING
" %s debugging increased min order, use "
1944 "slub_debug=O to disable.\n", s
->name
);
1946 for_each_online_node(node
) {
1947 struct kmem_cache_node
*n
= get_node(s
, node
);
1948 unsigned long nr_slabs
;
1949 unsigned long nr_objs
;
1950 unsigned long nr_free
;
1955 nr_free
= count_partial(n
, count_free
);
1956 nr_slabs
= node_nr_slabs(n
);
1957 nr_objs
= node_nr_objs(n
);
1960 " node %d: slabs: %ld, objs: %ld, free: %ld\n",
1961 node
, nr_slabs
, nr_objs
, nr_free
);
1966 * Slow path. The lockless freelist is empty or we need to perform
1969 * Interrupts are disabled.
1971 * Processing is still very fast if new objects have been freed to the
1972 * regular freelist. In that case we simply take over the regular freelist
1973 * as the lockless freelist and zap the regular freelist.
1975 * If that is not working then we fall back to the partial lists. We take the
1976 * first element of the freelist as the object to allocate now and move the
1977 * rest of the freelist to the lockless freelist.
1979 * And if we were unable to get a new slab from the partial slab lists then
1980 * we need to allocate a new slab. This is the slowest path since it involves
1981 * a call to the page allocator and the setup of a new slab.
1983 static void *__slab_alloc(struct kmem_cache
*s
, gfp_t gfpflags
, int node
,
1984 unsigned long addr
, struct kmem_cache_cpu
*c
)
1988 unsigned long flags
;
1990 unsigned long counters
;
1992 local_irq_save(flags
);
1993 #ifdef CONFIG_PREEMPT
1995 * We may have been preempted and rescheduled on a different
1996 * cpu before disabling interrupts. Need to reload cpu area
1999 c
= this_cpu_ptr(s
->cpu_slab
);
2002 /* We handle __GFP_ZERO in the caller */
2003 gfpflags
&= ~__GFP_ZERO
;
2009 if (unlikely(!node_match(c
, node
))) {
2010 stat(s
, ALLOC_NODE_MISMATCH
);
2011 deactivate_slab(s
, c
);
2015 stat(s
, ALLOC_SLOWPATH
);
2018 object
= page
->freelist
;
2019 counters
= page
->counters
;
2020 new.counters
= counters
;
2021 VM_BUG_ON(!new.frozen
);
2024 * If there is no object left then we use this loop to
2025 * deactivate the slab which is simple since no objects
2026 * are left in the slab and therefore we do not need to
2027 * put the page back onto the partial list.
2029 * If there are objects left then we retrieve them
2030 * and use them to refill the per cpu queue.
2033 new.inuse
= page
->objects
;
2034 new.frozen
= object
!= NULL
;
2036 } while (!__cmpxchg_double_slab(s
, page
,
2041 if (unlikely(!object
)) {
2043 stat(s
, DEACTIVATE_BYPASS
);
2047 stat(s
, ALLOC_REFILL
);
2050 VM_BUG_ON(!page
->frozen
);
2051 c
->freelist
= get_freepointer(s
, object
);
2052 c
->tid
= next_tid(c
->tid
);
2053 local_irq_restore(flags
);
2057 page
= get_partial(s
, gfpflags
, node
);
2059 stat(s
, ALLOC_FROM_PARTIAL
);
2060 object
= c
->freelist
;
2062 if (kmem_cache_debug(s
))
2067 page
= new_slab(s
, gfpflags
, node
);
2070 c
= __this_cpu_ptr(s
->cpu_slab
);
2075 * No other reference to the page yet so we can
2076 * muck around with it freely without cmpxchg
2078 object
= page
->freelist
;
2079 page
->freelist
= NULL
;
2080 page
->inuse
= page
->objects
;
2082 stat(s
, ALLOC_SLAB
);
2083 c
->node
= page_to_nid(page
);
2086 if (kmem_cache_debug(s
))
2090 if (!(gfpflags
& __GFP_NOWARN
) && printk_ratelimit())
2091 slab_out_of_memory(s
, gfpflags
, node
);
2092 local_irq_restore(flags
);
2096 if (!object
|| !alloc_debug_processing(s
, page
, object
, addr
))
2099 c
->freelist
= get_freepointer(s
, object
);
2100 deactivate_slab(s
, c
);
2102 c
->node
= NUMA_NO_NODE
;
2103 local_irq_restore(flags
);
2108 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2109 * have the fastpath folded into their functions. So no function call
2110 * overhead for requests that can be satisfied on the fastpath.
2112 * The fastpath works by first checking if the lockless freelist can be used.
2113 * If not then __slab_alloc is called for slow processing.
2115 * Otherwise we can simply pick the next object from the lockless free list.
2117 static __always_inline
void *slab_alloc(struct kmem_cache
*s
,
2118 gfp_t gfpflags
, int node
, unsigned long addr
)
2121 struct kmem_cache_cpu
*c
;
2124 if (slab_pre_alloc_hook(s
, gfpflags
))
2130 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2131 * enabled. We may switch back and forth between cpus while
2132 * reading from one cpu area. That does not matter as long
2133 * as we end up on the original cpu again when doing the cmpxchg.
2135 c
= __this_cpu_ptr(s
->cpu_slab
);
2138 * The transaction ids are globally unique per cpu and per operation on
2139 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2140 * occurs on the right processor and that there was no operation on the
2141 * linked list in between.
2146 object
= c
->freelist
;
2147 if (unlikely(!object
|| !node_match(c
, node
)))
2149 object
= __slab_alloc(s
, gfpflags
, node
, addr
, c
);
2153 * The cmpxchg will only match if there was no additional
2154 * operation and if we are on the right processor.
2156 * The cmpxchg does the following atomically (without lock semantics!)
2157 * 1. Relocate first pointer to the current per cpu area.
2158 * 2. Verify that tid and freelist have not been changed
2159 * 3. If they were not changed replace tid and freelist
2161 * Since this is without lock semantics the protection is only against
2162 * code executing on this cpu *not* from access by other cpus.
2164 if (unlikely(!irqsafe_cpu_cmpxchg_double(
2165 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2167 get_freepointer_safe(s
, object
), next_tid(tid
)))) {
2169 note_cmpxchg_failure("slab_alloc", s
, tid
);
2172 stat(s
, ALLOC_FASTPATH
);
2175 if (unlikely(gfpflags
& __GFP_ZERO
) && object
)
2176 memset(object
, 0, s
->objsize
);
2178 slab_post_alloc_hook(s
, gfpflags
, object
);
2183 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
2185 void *ret
= slab_alloc(s
, gfpflags
, NUMA_NO_NODE
, _RET_IP_
);
2187 trace_kmem_cache_alloc(_RET_IP_
, ret
, s
->objsize
, s
->size
, gfpflags
);
2191 EXPORT_SYMBOL(kmem_cache_alloc
);
2193 #ifdef CONFIG_TRACING
2194 void *kmem_cache_alloc_trace(struct kmem_cache
*s
, gfp_t gfpflags
, size_t size
)
2196 void *ret
= slab_alloc(s
, gfpflags
, NUMA_NO_NODE
, _RET_IP_
);
2197 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, gfpflags
);
2200 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
2202 void *kmalloc_order_trace(size_t size
, gfp_t flags
, unsigned int order
)
2204 void *ret
= kmalloc_order(size
, flags
, order
);
2205 trace_kmalloc(_RET_IP_
, ret
, size
, PAGE_SIZE
<< order
, flags
);
2208 EXPORT_SYMBOL(kmalloc_order_trace
);
2212 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
2214 void *ret
= slab_alloc(s
, gfpflags
, node
, _RET_IP_
);
2216 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
2217 s
->objsize
, s
->size
, gfpflags
, node
);
2221 EXPORT_SYMBOL(kmem_cache_alloc_node
);
2223 #ifdef CONFIG_TRACING
2224 void *kmem_cache_alloc_node_trace(struct kmem_cache
*s
,
2226 int node
, size_t size
)
2228 void *ret
= slab_alloc(s
, gfpflags
, node
, _RET_IP_
);
2230 trace_kmalloc_node(_RET_IP_
, ret
,
2231 size
, s
->size
, gfpflags
, node
);
2234 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
2239 * Slow patch handling. This may still be called frequently since objects
2240 * have a longer lifetime than the cpu slabs in most processing loads.
2242 * So we still attempt to reduce cache line usage. Just take the slab
2243 * lock and free the item. If there is no additional partial page
2244 * handling required then we can return immediately.
2246 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
2247 void *x
, unsigned long addr
)
2250 void **object
= (void *)x
;
2254 unsigned long counters
;
2255 struct kmem_cache_node
*n
= NULL
;
2256 unsigned long uninitialized_var(flags
);
2258 stat(s
, FREE_SLOWPATH
);
2260 if (kmem_cache_debug(s
) && !free_debug_processing(s
, page
, x
, addr
))
2264 prior
= page
->freelist
;
2265 counters
= page
->counters
;
2266 set_freepointer(s
, object
, prior
);
2267 new.counters
= counters
;
2268 was_frozen
= new.frozen
;
2270 if ((!new.inuse
|| !prior
) && !was_frozen
&& !n
) {
2271 n
= get_node(s
, page_to_nid(page
));
2273 * Speculatively acquire the list_lock.
2274 * If the cmpxchg does not succeed then we may
2275 * drop the list_lock without any processing.
2277 * Otherwise the list_lock will synchronize with
2278 * other processors updating the list of slabs.
2280 spin_lock_irqsave(&n
->list_lock
, flags
);
2284 } while (!cmpxchg_double_slab(s
, page
,
2286 object
, new.counters
,
2291 * The list lock was not taken therefore no list
2292 * activity can be necessary.
2295 stat(s
, FREE_FROZEN
);
2300 * was_frozen may have been set after we acquired the list_lock in
2301 * an earlier loop. So we need to check it here again.
2304 stat(s
, FREE_FROZEN
);
2306 if (unlikely(!inuse
&& n
->nr_partial
> s
->min_partial
))
2310 * Objects left in the slab. If it was not on the partial list before
2313 if (unlikely(!prior
)) {
2314 remove_full(s
, page
);
2315 add_partial(n
, page
, 0);
2316 stat(s
, FREE_ADD_PARTIAL
);
2319 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2325 * Slab still on the partial list.
2327 remove_partial(n
, page
);
2328 stat(s
, FREE_REMOVE_PARTIAL
);
2331 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2333 discard_slab(s
, page
);
2337 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2338 * can perform fastpath freeing without additional function calls.
2340 * The fastpath is only possible if we are freeing to the current cpu slab
2341 * of this processor. This typically the case if we have just allocated
2344 * If fastpath is not possible then fall back to __slab_free where we deal
2345 * with all sorts of special processing.
2347 static __always_inline
void slab_free(struct kmem_cache
*s
,
2348 struct page
*page
, void *x
, unsigned long addr
)
2350 void **object
= (void *)x
;
2351 struct kmem_cache_cpu
*c
;
2354 slab_free_hook(s
, x
);
2359 * Determine the currently cpus per cpu slab.
2360 * The cpu may change afterward. However that does not matter since
2361 * data is retrieved via this pointer. If we are on the same cpu
2362 * during the cmpxchg then the free will succedd.
2364 c
= __this_cpu_ptr(s
->cpu_slab
);
2369 if (likely(page
== c
->page
)) {
2370 set_freepointer(s
, object
, c
->freelist
);
2372 if (unlikely(!irqsafe_cpu_cmpxchg_double(
2373 s
->cpu_slab
->freelist
, s
->cpu_slab
->tid
,
2375 object
, next_tid(tid
)))) {
2377 note_cmpxchg_failure("slab_free", s
, tid
);
2380 stat(s
, FREE_FASTPATH
);
2382 __slab_free(s
, page
, x
, addr
);
2386 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
2390 page
= virt_to_head_page(x
);
2392 slab_free(s
, page
, x
, _RET_IP_
);
2394 trace_kmem_cache_free(_RET_IP_
, x
);
2396 EXPORT_SYMBOL(kmem_cache_free
);
2399 * Object placement in a slab is made very easy because we always start at
2400 * offset 0. If we tune the size of the object to the alignment then we can
2401 * get the required alignment by putting one properly sized object after
2404 * Notice that the allocation order determines the sizes of the per cpu
2405 * caches. Each processor has always one slab available for allocations.
2406 * Increasing the allocation order reduces the number of times that slabs
2407 * must be moved on and off the partial lists and is therefore a factor in
2412 * Mininum / Maximum order of slab pages. This influences locking overhead
2413 * and slab fragmentation. A higher order reduces the number of partial slabs
2414 * and increases the number of allocations possible without having to
2415 * take the list_lock.
2417 static int slub_min_order
;
2418 static int slub_max_order
= PAGE_ALLOC_COSTLY_ORDER
;
2419 static int slub_min_objects
;
2422 * Merge control. If this is set then no merging of slab caches will occur.
2423 * (Could be removed. This was introduced to pacify the merge skeptics.)
2425 static int slub_nomerge
;
2428 * Calculate the order of allocation given an slab object size.
2430 * The order of allocation has significant impact on performance and other
2431 * system components. Generally order 0 allocations should be preferred since
2432 * order 0 does not cause fragmentation in the page allocator. Larger objects
2433 * be problematic to put into order 0 slabs because there may be too much
2434 * unused space left. We go to a higher order if more than 1/16th of the slab
2437 * In order to reach satisfactory performance we must ensure that a minimum
2438 * number of objects is in one slab. Otherwise we may generate too much
2439 * activity on the partial lists which requires taking the list_lock. This is
2440 * less a concern for large slabs though which are rarely used.
2442 * slub_max_order specifies the order where we begin to stop considering the
2443 * number of objects in a slab as critical. If we reach slub_max_order then
2444 * we try to keep the page order as low as possible. So we accept more waste
2445 * of space in favor of a small page order.
2447 * Higher order allocations also allow the placement of more objects in a
2448 * slab and thereby reduce object handling overhead. If the user has
2449 * requested a higher mininum order then we start with that one instead of
2450 * the smallest order which will fit the object.
2452 static inline int slab_order(int size
, int min_objects
,
2453 int max_order
, int fract_leftover
, int reserved
)
2457 int min_order
= slub_min_order
;
2459 if (order_objects(min_order
, size
, reserved
) > MAX_OBJS_PER_PAGE
)
2460 return get_order(size
* MAX_OBJS_PER_PAGE
) - 1;
2462 for (order
= max(min_order
,
2463 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
2464 order
<= max_order
; order
++) {
2466 unsigned long slab_size
= PAGE_SIZE
<< order
;
2468 if (slab_size
< min_objects
* size
+ reserved
)
2471 rem
= (slab_size
- reserved
) % size
;
2473 if (rem
<= slab_size
/ fract_leftover
)
2481 static inline int calculate_order(int size
, int reserved
)
2489 * Attempt to find best configuration for a slab. This
2490 * works by first attempting to generate a layout with
2491 * the best configuration and backing off gradually.
2493 * First we reduce the acceptable waste in a slab. Then
2494 * we reduce the minimum objects required in a slab.
2496 min_objects
= slub_min_objects
;
2498 min_objects
= 4 * (fls(nr_cpu_ids
) + 1);
2499 max_objects
= order_objects(slub_max_order
, size
, reserved
);
2500 min_objects
= min(min_objects
, max_objects
);
2502 while (min_objects
> 1) {
2504 while (fraction
>= 4) {
2505 order
= slab_order(size
, min_objects
,
2506 slub_max_order
, fraction
, reserved
);
2507 if (order
<= slub_max_order
)
2515 * We were unable to place multiple objects in a slab. Now
2516 * lets see if we can place a single object there.
2518 order
= slab_order(size
, 1, slub_max_order
, 1, reserved
);
2519 if (order
<= slub_max_order
)
2523 * Doh this slab cannot be placed using slub_max_order.
2525 order
= slab_order(size
, 1, MAX_ORDER
, 1, reserved
);
2526 if (order
< MAX_ORDER
)
2532 * Figure out what the alignment of the objects will be.
2534 static unsigned long calculate_alignment(unsigned long flags
,
2535 unsigned long align
, unsigned long size
)
2538 * If the user wants hardware cache aligned objects then follow that
2539 * suggestion if the object is sufficiently large.
2541 * The hardware cache alignment cannot override the specified
2542 * alignment though. If that is greater then use it.
2544 if (flags
& SLAB_HWCACHE_ALIGN
) {
2545 unsigned long ralign
= cache_line_size();
2546 while (size
<= ralign
/ 2)
2548 align
= max(align
, ralign
);
2551 if (align
< ARCH_SLAB_MINALIGN
)
2552 align
= ARCH_SLAB_MINALIGN
;
2554 return ALIGN(align
, sizeof(void *));
2558 init_kmem_cache_node(struct kmem_cache_node
*n
, struct kmem_cache
*s
)
2561 spin_lock_init(&n
->list_lock
);
2562 INIT_LIST_HEAD(&n
->partial
);
2563 #ifdef CONFIG_SLUB_DEBUG
2564 atomic_long_set(&n
->nr_slabs
, 0);
2565 atomic_long_set(&n
->total_objects
, 0);
2566 INIT_LIST_HEAD(&n
->full
);
2570 static inline int alloc_kmem_cache_cpus(struct kmem_cache
*s
)
2572 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE
<
2573 SLUB_PAGE_SHIFT
* sizeof(struct kmem_cache_cpu
));
2576 * Must align to double word boundary for the double cmpxchg
2577 * instructions to work; see __pcpu_double_call_return_bool().
2579 s
->cpu_slab
= __alloc_percpu(sizeof(struct kmem_cache_cpu
),
2580 2 * sizeof(void *));
2585 init_kmem_cache_cpus(s
);
2590 static struct kmem_cache
*kmem_cache_node
;
2593 * No kmalloc_node yet so do it by hand. We know that this is the first
2594 * slab on the node for this slabcache. There are no concurrent accesses
2597 * Note that this function only works on the kmalloc_node_cache
2598 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2599 * memory on a fresh node that has no slab structures yet.
2601 static void early_kmem_cache_node_alloc(int node
)
2604 struct kmem_cache_node
*n
;
2606 BUG_ON(kmem_cache_node
->size
< sizeof(struct kmem_cache_node
));
2608 page
= new_slab(kmem_cache_node
, GFP_NOWAIT
, node
);
2611 if (page_to_nid(page
) != node
) {
2612 printk(KERN_ERR
"SLUB: Unable to allocate memory from "
2614 printk(KERN_ERR
"SLUB: Allocating a useless per node structure "
2615 "in order to be able to continue\n");
2620 page
->freelist
= get_freepointer(kmem_cache_node
, n
);
2623 kmem_cache_node
->node
[node
] = n
;
2624 #ifdef CONFIG_SLUB_DEBUG
2625 init_object(kmem_cache_node
, n
, SLUB_RED_ACTIVE
);
2626 init_tracking(kmem_cache_node
, n
);
2628 init_kmem_cache_node(n
, kmem_cache_node
);
2629 inc_slabs_node(kmem_cache_node
, node
, page
->objects
);
2631 add_partial(n
, page
, 0);
2634 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
2638 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2639 struct kmem_cache_node
*n
= s
->node
[node
];
2642 kmem_cache_free(kmem_cache_node
, n
);
2644 s
->node
[node
] = NULL
;
2648 static int init_kmem_cache_nodes(struct kmem_cache
*s
)
2652 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2653 struct kmem_cache_node
*n
;
2655 if (slab_state
== DOWN
) {
2656 early_kmem_cache_node_alloc(node
);
2659 n
= kmem_cache_alloc_node(kmem_cache_node
,
2663 free_kmem_cache_nodes(s
);
2668 init_kmem_cache_node(n
, s
);
2673 static void set_min_partial(struct kmem_cache
*s
, unsigned long min
)
2675 if (min
< MIN_PARTIAL
)
2677 else if (min
> MAX_PARTIAL
)
2679 s
->min_partial
= min
;
2683 * calculate_sizes() determines the order and the distribution of data within
2686 static int calculate_sizes(struct kmem_cache
*s
, int forced_order
)
2688 unsigned long flags
= s
->flags
;
2689 unsigned long size
= s
->objsize
;
2690 unsigned long align
= s
->align
;
2694 * Round up object size to the next word boundary. We can only
2695 * place the free pointer at word boundaries and this determines
2696 * the possible location of the free pointer.
2698 size
= ALIGN(size
, sizeof(void *));
2700 #ifdef CONFIG_SLUB_DEBUG
2702 * Determine if we can poison the object itself. If the user of
2703 * the slab may touch the object after free or before allocation
2704 * then we should never poison the object itself.
2706 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
2708 s
->flags
|= __OBJECT_POISON
;
2710 s
->flags
&= ~__OBJECT_POISON
;
2714 * If we are Redzoning then check if there is some space between the
2715 * end of the object and the free pointer. If not then add an
2716 * additional word to have some bytes to store Redzone information.
2718 if ((flags
& SLAB_RED_ZONE
) && size
== s
->objsize
)
2719 size
+= sizeof(void *);
2723 * With that we have determined the number of bytes in actual use
2724 * by the object. This is the potential offset to the free pointer.
2728 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
2731 * Relocate free pointer after the object if it is not
2732 * permitted to overwrite the first word of the object on
2735 * This is the case if we do RCU, have a constructor or
2736 * destructor or are poisoning the objects.
2739 size
+= sizeof(void *);
2742 #ifdef CONFIG_SLUB_DEBUG
2743 if (flags
& SLAB_STORE_USER
)
2745 * Need to store information about allocs and frees after
2748 size
+= 2 * sizeof(struct track
);
2750 if (flags
& SLAB_RED_ZONE
)
2752 * Add some empty padding so that we can catch
2753 * overwrites from earlier objects rather than let
2754 * tracking information or the free pointer be
2755 * corrupted if a user writes before the start
2758 size
+= sizeof(void *);
2762 * Determine the alignment based on various parameters that the
2763 * user specified and the dynamic determination of cache line size
2766 align
= calculate_alignment(flags
, align
, s
->objsize
);
2770 * SLUB stores one object immediately after another beginning from
2771 * offset 0. In order to align the objects we have to simply size
2772 * each object to conform to the alignment.
2774 size
= ALIGN(size
, align
);
2776 if (forced_order
>= 0)
2777 order
= forced_order
;
2779 order
= calculate_order(size
, s
->reserved
);
2786 s
->allocflags
|= __GFP_COMP
;
2788 if (s
->flags
& SLAB_CACHE_DMA
)
2789 s
->allocflags
|= SLUB_DMA
;
2791 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
2792 s
->allocflags
|= __GFP_RECLAIMABLE
;
2795 * Determine the number of objects per slab
2797 s
->oo
= oo_make(order
, size
, s
->reserved
);
2798 s
->min
= oo_make(get_order(size
), size
, s
->reserved
);
2799 if (oo_objects(s
->oo
) > oo_objects(s
->max
))
2802 return !!oo_objects(s
->oo
);
2806 static int kmem_cache_open(struct kmem_cache
*s
,
2807 const char *name
, size_t size
,
2808 size_t align
, unsigned long flags
,
2809 void (*ctor
)(void *))
2811 memset(s
, 0, kmem_size
);
2816 s
->flags
= kmem_cache_flags(size
, flags
, name
, ctor
);
2819 if (need_reserve_slab_rcu
&& (s
->flags
& SLAB_DESTROY_BY_RCU
))
2820 s
->reserved
= sizeof(struct rcu_head
);
2822 if (!calculate_sizes(s
, -1))
2824 if (disable_higher_order_debug
) {
2826 * Disable debugging flags that store metadata if the min slab
2829 if (get_order(s
->size
) > get_order(s
->objsize
)) {
2830 s
->flags
&= ~DEBUG_METADATA_FLAGS
;
2832 if (!calculate_sizes(s
, -1))
2837 #ifdef CONFIG_CMPXCHG_DOUBLE
2838 if (system_has_cmpxchg_double() && (s
->flags
& SLAB_DEBUG_FLAGS
) == 0)
2839 /* Enable fast mode */
2840 s
->flags
|= __CMPXCHG_DOUBLE
;
2844 * The larger the object size is, the more pages we want on the partial
2845 * list to avoid pounding the page allocator excessively.
2847 set_min_partial(s
, ilog2(s
->size
));
2850 s
->remote_node_defrag_ratio
= 1000;
2852 if (!init_kmem_cache_nodes(s
))
2855 if (alloc_kmem_cache_cpus(s
))
2858 free_kmem_cache_nodes(s
);
2860 if (flags
& SLAB_PANIC
)
2861 panic("Cannot create slab %s size=%lu realsize=%u "
2862 "order=%u offset=%u flags=%lx\n",
2863 s
->name
, (unsigned long)size
, s
->size
, oo_order(s
->oo
),
2869 * Determine the size of a slab object
2871 unsigned int kmem_cache_size(struct kmem_cache
*s
)
2875 EXPORT_SYMBOL(kmem_cache_size
);
2877 static void list_slab_objects(struct kmem_cache
*s
, struct page
*page
,
2880 #ifdef CONFIG_SLUB_DEBUG
2881 void *addr
= page_address(page
);
2883 unsigned long *map
= kzalloc(BITS_TO_LONGS(page
->objects
) *
2884 sizeof(long), GFP_ATOMIC
);
2887 slab_err(s
, page
, "%s", text
);
2890 get_map(s
, page
, map
);
2891 for_each_object(p
, s
, addr
, page
->objects
) {
2893 if (!test_bit(slab_index(p
, s
, addr
), map
)) {
2894 printk(KERN_ERR
"INFO: Object 0x%p @offset=%tu\n",
2896 print_tracking(s
, p
);
2905 * Attempt to free all partial slabs on a node.
2907 static void free_partial(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
2909 unsigned long flags
;
2910 struct page
*page
, *h
;
2912 spin_lock_irqsave(&n
->list_lock
, flags
);
2913 list_for_each_entry_safe(page
, h
, &n
->partial
, lru
) {
2915 remove_partial(n
, page
);
2916 discard_slab(s
, page
);
2918 list_slab_objects(s
, page
,
2919 "Objects remaining on kmem_cache_close()");
2922 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2926 * Release all resources used by a slab cache.
2928 static inline int kmem_cache_close(struct kmem_cache
*s
)
2933 free_percpu(s
->cpu_slab
);
2934 /* Attempt to free all objects */
2935 for_each_node_state(node
, N_NORMAL_MEMORY
) {
2936 struct kmem_cache_node
*n
= get_node(s
, node
);
2939 if (n
->nr_partial
|| slabs_node(s
, node
))
2942 free_kmem_cache_nodes(s
);
2947 * Close a cache and release the kmem_cache structure
2948 * (must be used for caches created using kmem_cache_create)
2950 void kmem_cache_destroy(struct kmem_cache
*s
)
2952 down_write(&slub_lock
);
2956 if (kmem_cache_close(s
)) {
2957 printk(KERN_ERR
"SLUB %s: %s called for cache that "
2958 "still has objects.\n", s
->name
, __func__
);
2961 if (s
->flags
& SLAB_DESTROY_BY_RCU
)
2963 sysfs_slab_remove(s
);
2965 up_write(&slub_lock
);
2967 EXPORT_SYMBOL(kmem_cache_destroy
);
2969 /********************************************************************
2971 *******************************************************************/
2973 struct kmem_cache
*kmalloc_caches
[SLUB_PAGE_SHIFT
];
2974 EXPORT_SYMBOL(kmalloc_caches
);
2976 static struct kmem_cache
*kmem_cache
;
2978 #ifdef CONFIG_ZONE_DMA
2979 static struct kmem_cache
*kmalloc_dma_caches
[SLUB_PAGE_SHIFT
];
2982 static int __init
setup_slub_min_order(char *str
)
2984 get_option(&str
, &slub_min_order
);
2989 __setup("slub_min_order=", setup_slub_min_order
);
2991 static int __init
setup_slub_max_order(char *str
)
2993 get_option(&str
, &slub_max_order
);
2994 slub_max_order
= min(slub_max_order
, MAX_ORDER
- 1);
2999 __setup("slub_max_order=", setup_slub_max_order
);
3001 static int __init
setup_slub_min_objects(char *str
)
3003 get_option(&str
, &slub_min_objects
);
3008 __setup("slub_min_objects=", setup_slub_min_objects
);
3010 static int __init
setup_slub_nomerge(char *str
)
3016 __setup("slub_nomerge", setup_slub_nomerge
);
3018 static struct kmem_cache
*__init
create_kmalloc_cache(const char *name
,
3019 int size
, unsigned int flags
)
3021 struct kmem_cache
*s
;
3023 s
= kmem_cache_alloc(kmem_cache
, GFP_NOWAIT
);
3026 * This function is called with IRQs disabled during early-boot on
3027 * single CPU so there's no need to take slub_lock here.
3029 if (!kmem_cache_open(s
, name
, size
, ARCH_KMALLOC_MINALIGN
,
3033 list_add(&s
->list
, &slab_caches
);
3037 panic("Creation of kmalloc slab %s size=%d failed.\n", name
, size
);
3042 * Conversion table for small slabs sizes / 8 to the index in the
3043 * kmalloc array. This is necessary for slabs < 192 since we have non power
3044 * of two cache sizes there. The size of larger slabs can be determined using
3047 static s8 size_index
[24] = {
3074 static inline int size_index_elem(size_t bytes
)
3076 return (bytes
- 1) / 8;
3079 static struct kmem_cache
*get_slab(size_t size
, gfp_t flags
)
3085 return ZERO_SIZE_PTR
;
3087 index
= size_index
[size_index_elem(size
)];
3089 index
= fls(size
- 1);
3091 #ifdef CONFIG_ZONE_DMA
3092 if (unlikely((flags
& SLUB_DMA
)))
3093 return kmalloc_dma_caches
[index
];
3096 return kmalloc_caches
[index
];
3099 void *__kmalloc(size_t size
, gfp_t flags
)
3101 struct kmem_cache
*s
;
3104 if (unlikely(size
> SLUB_MAX_SIZE
))
3105 return kmalloc_large(size
, flags
);
3107 s
= get_slab(size
, flags
);
3109 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3112 ret
= slab_alloc(s
, flags
, NUMA_NO_NODE
, _RET_IP_
);
3114 trace_kmalloc(_RET_IP_
, ret
, size
, s
->size
, flags
);
3118 EXPORT_SYMBOL(__kmalloc
);
3121 static void *kmalloc_large_node(size_t size
, gfp_t flags
, int node
)
3126 flags
|= __GFP_COMP
| __GFP_NOTRACK
;
3127 page
= alloc_pages_node(node
, flags
, get_order(size
));
3129 ptr
= page_address(page
);
3131 kmemleak_alloc(ptr
, size
, 1, flags
);
3135 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3137 struct kmem_cache
*s
;
3140 if (unlikely(size
> SLUB_MAX_SIZE
)) {
3141 ret
= kmalloc_large_node(size
, flags
, node
);
3143 trace_kmalloc_node(_RET_IP_
, ret
,
3144 size
, PAGE_SIZE
<< get_order(size
),
3150 s
= get_slab(size
, flags
);
3152 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3155 ret
= slab_alloc(s
, flags
, node
, _RET_IP_
);
3157 trace_kmalloc_node(_RET_IP_
, ret
, size
, s
->size
, flags
, node
);
3161 EXPORT_SYMBOL(__kmalloc_node
);
3164 size_t ksize(const void *object
)
3168 if (unlikely(object
== ZERO_SIZE_PTR
))
3171 page
= virt_to_head_page(object
);
3173 if (unlikely(!PageSlab(page
))) {
3174 WARN_ON(!PageCompound(page
));
3175 return PAGE_SIZE
<< compound_order(page
);
3178 return slab_ksize(page
->slab
);
3180 EXPORT_SYMBOL(ksize
);
3182 void kfree(const void *x
)
3185 void *object
= (void *)x
;
3187 trace_kfree(_RET_IP_
, x
);
3189 if (unlikely(ZERO_OR_NULL_PTR(x
)))
3192 page
= virt_to_head_page(x
);
3193 if (unlikely(!PageSlab(page
))) {
3194 BUG_ON(!PageCompound(page
));
3199 slab_free(page
->slab
, page
, object
, _RET_IP_
);
3201 EXPORT_SYMBOL(kfree
);
3204 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3205 * the remaining slabs by the number of items in use. The slabs with the
3206 * most items in use come first. New allocations will then fill those up
3207 * and thus they can be removed from the partial lists.
3209 * The slabs with the least items are placed last. This results in them
3210 * being allocated from last increasing the chance that the last objects
3211 * are freed in them.
3213 int kmem_cache_shrink(struct kmem_cache
*s
)
3217 struct kmem_cache_node
*n
;
3220 int objects
= oo_objects(s
->max
);
3221 struct list_head
*slabs_by_inuse
=
3222 kmalloc(sizeof(struct list_head
) * objects
, GFP_KERNEL
);
3223 unsigned long flags
;
3225 if (!slabs_by_inuse
)
3229 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3230 n
= get_node(s
, node
);
3235 for (i
= 0; i
< objects
; i
++)
3236 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
3238 spin_lock_irqsave(&n
->list_lock
, flags
);
3241 * Build lists indexed by the items in use in each slab.
3243 * Note that concurrent frees may occur while we hold the
3244 * list_lock. page->inuse here is the upper limit.
3246 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
3248 remove_partial(n
, page
);
3249 discard_slab(s
, page
);
3251 list_move(&page
->lru
,
3252 slabs_by_inuse
+ page
->inuse
);
3257 * Rebuild the partial list with the slabs filled up most
3258 * first and the least used slabs at the end.
3260 for (i
= objects
- 1; i
>= 0; i
--)
3261 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
3263 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3266 kfree(slabs_by_inuse
);
3269 EXPORT_SYMBOL(kmem_cache_shrink
);
3271 #if defined(CONFIG_MEMORY_HOTPLUG)
3272 static int slab_mem_going_offline_callback(void *arg
)
3274 struct kmem_cache
*s
;
3276 down_read(&slub_lock
);
3277 list_for_each_entry(s
, &slab_caches
, list
)
3278 kmem_cache_shrink(s
);
3279 up_read(&slub_lock
);
3284 static void slab_mem_offline_callback(void *arg
)
3286 struct kmem_cache_node
*n
;
3287 struct kmem_cache
*s
;
3288 struct memory_notify
*marg
= arg
;
3291 offline_node
= marg
->status_change_nid
;
3294 * If the node still has available memory. we need kmem_cache_node
3297 if (offline_node
< 0)
3300 down_read(&slub_lock
);
3301 list_for_each_entry(s
, &slab_caches
, list
) {
3302 n
= get_node(s
, offline_node
);
3305 * if n->nr_slabs > 0, slabs still exist on the node
3306 * that is going down. We were unable to free them,
3307 * and offline_pages() function shouldn't call this
3308 * callback. So, we must fail.
3310 BUG_ON(slabs_node(s
, offline_node
));
3312 s
->node
[offline_node
] = NULL
;
3313 kmem_cache_free(kmem_cache_node
, n
);
3316 up_read(&slub_lock
);
3319 static int slab_mem_going_online_callback(void *arg
)
3321 struct kmem_cache_node
*n
;
3322 struct kmem_cache
*s
;
3323 struct memory_notify
*marg
= arg
;
3324 int nid
= marg
->status_change_nid
;
3328 * If the node's memory is already available, then kmem_cache_node is
3329 * already created. Nothing to do.
3335 * We are bringing a node online. No memory is available yet. We must
3336 * allocate a kmem_cache_node structure in order to bring the node
3339 down_read(&slub_lock
);
3340 list_for_each_entry(s
, &slab_caches
, list
) {
3342 * XXX: kmem_cache_alloc_node will fallback to other nodes
3343 * since memory is not yet available from the node that
3346 n
= kmem_cache_alloc(kmem_cache_node
, GFP_KERNEL
);
3351 init_kmem_cache_node(n
, s
);
3355 up_read(&slub_lock
);
3359 static int slab_memory_callback(struct notifier_block
*self
,
3360 unsigned long action
, void *arg
)
3365 case MEM_GOING_ONLINE
:
3366 ret
= slab_mem_going_online_callback(arg
);
3368 case MEM_GOING_OFFLINE
:
3369 ret
= slab_mem_going_offline_callback(arg
);
3372 case MEM_CANCEL_ONLINE
:
3373 slab_mem_offline_callback(arg
);
3376 case MEM_CANCEL_OFFLINE
:
3380 ret
= notifier_from_errno(ret
);
3386 #endif /* CONFIG_MEMORY_HOTPLUG */
3388 /********************************************************************
3389 * Basic setup of slabs
3390 *******************************************************************/
3393 * Used for early kmem_cache structures that were allocated using
3394 * the page allocator
3397 static void __init
kmem_cache_bootstrap_fixup(struct kmem_cache
*s
)
3401 list_add(&s
->list
, &slab_caches
);
3404 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3405 struct kmem_cache_node
*n
= get_node(s
, node
);
3409 list_for_each_entry(p
, &n
->partial
, lru
)
3412 #ifdef CONFIG_SLUB_DEBUG
3413 list_for_each_entry(p
, &n
->full
, lru
)
3420 void __init
kmem_cache_init(void)
3424 struct kmem_cache
*temp_kmem_cache
;
3426 struct kmem_cache
*temp_kmem_cache_node
;
3427 unsigned long kmalloc_size
;
3429 kmem_size
= offsetof(struct kmem_cache
, node
) +
3430 nr_node_ids
* sizeof(struct kmem_cache_node
*);
3432 /* Allocate two kmem_caches from the page allocator */
3433 kmalloc_size
= ALIGN(kmem_size
, cache_line_size());
3434 order
= get_order(2 * kmalloc_size
);
3435 kmem_cache
= (void *)__get_free_pages(GFP_NOWAIT
, order
);
3438 * Must first have the slab cache available for the allocations of the
3439 * struct kmem_cache_node's. There is special bootstrap code in
3440 * kmem_cache_open for slab_state == DOWN.
3442 kmem_cache_node
= (void *)kmem_cache
+ kmalloc_size
;
3444 kmem_cache_open(kmem_cache_node
, "kmem_cache_node",
3445 sizeof(struct kmem_cache_node
),
3446 0, SLAB_HWCACHE_ALIGN
| SLAB_PANIC
, NULL
);
3448 hotplug_memory_notifier(slab_memory_callback
, SLAB_CALLBACK_PRI
);
3450 /* Able to allocate the per node structures */
3451 slab_state
= PARTIAL
;
3453 temp_kmem_cache
= kmem_cache
;
3454 kmem_cache_open(kmem_cache
, "kmem_cache", kmem_size
,
3455 0, SLAB_HWCACHE_ALIGN
| SLAB_PANIC
, NULL
);
3456 kmem_cache
= kmem_cache_alloc(kmem_cache
, GFP_NOWAIT
);
3457 memcpy(kmem_cache
, temp_kmem_cache
, kmem_size
);
3460 * Allocate kmem_cache_node properly from the kmem_cache slab.
3461 * kmem_cache_node is separately allocated so no need to
3462 * update any list pointers.
3464 temp_kmem_cache_node
= kmem_cache_node
;
3466 kmem_cache_node
= kmem_cache_alloc(kmem_cache
, GFP_NOWAIT
);
3467 memcpy(kmem_cache_node
, temp_kmem_cache_node
, kmem_size
);
3469 kmem_cache_bootstrap_fixup(kmem_cache_node
);
3472 kmem_cache_bootstrap_fixup(kmem_cache
);
3474 /* Free temporary boot structure */
3475 free_pages((unsigned long)temp_kmem_cache
, order
);
3477 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3480 * Patch up the size_index table if we have strange large alignment
3481 * requirements for the kmalloc array. This is only the case for
3482 * MIPS it seems. The standard arches will not generate any code here.
3484 * Largest permitted alignment is 256 bytes due to the way we
3485 * handle the index determination for the smaller caches.
3487 * Make sure that nothing crazy happens if someone starts tinkering
3488 * around with ARCH_KMALLOC_MINALIGN
3490 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 256 ||
3491 (KMALLOC_MIN_SIZE
& (KMALLOC_MIN_SIZE
- 1)));
3493 for (i
= 8; i
< KMALLOC_MIN_SIZE
; i
+= 8) {
3494 int elem
= size_index_elem(i
);
3495 if (elem
>= ARRAY_SIZE(size_index
))
3497 size_index
[elem
] = KMALLOC_SHIFT_LOW
;
3500 if (KMALLOC_MIN_SIZE
== 64) {
3502 * The 96 byte size cache is not used if the alignment
3505 for (i
= 64 + 8; i
<= 96; i
+= 8)
3506 size_index
[size_index_elem(i
)] = 7;
3507 } else if (KMALLOC_MIN_SIZE
== 128) {
3509 * The 192 byte sized cache is not used if the alignment
3510 * is 128 byte. Redirect kmalloc to use the 256 byte cache
3513 for (i
= 128 + 8; i
<= 192; i
+= 8)
3514 size_index
[size_index_elem(i
)] = 8;
3517 /* Caches that are not of the two-to-the-power-of size */
3518 if (KMALLOC_MIN_SIZE
<= 32) {
3519 kmalloc_caches
[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
3523 if (KMALLOC_MIN_SIZE
<= 64) {
3524 kmalloc_caches
[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
3528 for (i
= KMALLOC_SHIFT_LOW
; i
< SLUB_PAGE_SHIFT
; i
++) {
3529 kmalloc_caches
[i
] = create_kmalloc_cache("kmalloc", 1 << i
, 0);
3535 /* Provide the correct kmalloc names now that the caches are up */
3536 if (KMALLOC_MIN_SIZE
<= 32) {
3537 kmalloc_caches
[1]->name
= kstrdup(kmalloc_caches
[1]->name
, GFP_NOWAIT
);
3538 BUG_ON(!kmalloc_caches
[1]->name
);
3541 if (KMALLOC_MIN_SIZE
<= 64) {
3542 kmalloc_caches
[2]->name
= kstrdup(kmalloc_caches
[2]->name
, GFP_NOWAIT
);
3543 BUG_ON(!kmalloc_caches
[2]->name
);
3546 for (i
= KMALLOC_SHIFT_LOW
; i
< SLUB_PAGE_SHIFT
; i
++) {
3547 char *s
= kasprintf(GFP_NOWAIT
, "kmalloc-%d", 1 << i
);
3550 kmalloc_caches
[i
]->name
= s
;
3554 register_cpu_notifier(&slab_notifier
);
3557 #ifdef CONFIG_ZONE_DMA
3558 for (i
= 0; i
< SLUB_PAGE_SHIFT
; i
++) {
3559 struct kmem_cache
*s
= kmalloc_caches
[i
];
3562 char *name
= kasprintf(GFP_NOWAIT
,
3563 "dma-kmalloc-%d", s
->objsize
);
3566 kmalloc_dma_caches
[i
] = create_kmalloc_cache(name
,
3567 s
->objsize
, SLAB_CACHE_DMA
);
3572 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3573 " CPUs=%d, Nodes=%d\n",
3574 caches
, cache_line_size(),
3575 slub_min_order
, slub_max_order
, slub_min_objects
,
3576 nr_cpu_ids
, nr_node_ids
);
3579 void __init
kmem_cache_init_late(void)
3584 * Find a mergeable slab cache
3586 static int slab_unmergeable(struct kmem_cache
*s
)
3588 if (slub_nomerge
|| (s
->flags
& SLUB_NEVER_MERGE
))
3595 * We may have set a slab to be unmergeable during bootstrap.
3597 if (s
->refcount
< 0)
3603 static struct kmem_cache
*find_mergeable(size_t size
,
3604 size_t align
, unsigned long flags
, const char *name
,
3605 void (*ctor
)(void *))
3607 struct kmem_cache
*s
;
3609 if (slub_nomerge
|| (flags
& SLUB_NEVER_MERGE
))
3615 size
= ALIGN(size
, sizeof(void *));
3616 align
= calculate_alignment(flags
, align
, size
);
3617 size
= ALIGN(size
, align
);
3618 flags
= kmem_cache_flags(size
, flags
, name
, NULL
);
3620 list_for_each_entry(s
, &slab_caches
, list
) {
3621 if (slab_unmergeable(s
))
3627 if ((flags
& SLUB_MERGE_SAME
) != (s
->flags
& SLUB_MERGE_SAME
))
3630 * Check if alignment is compatible.
3631 * Courtesy of Adrian Drzewiecki
3633 if ((s
->size
& ~(align
- 1)) != s
->size
)
3636 if (s
->size
- size
>= sizeof(void *))
3644 struct kmem_cache
*kmem_cache_create(const char *name
, size_t size
,
3645 size_t align
, unsigned long flags
, void (*ctor
)(void *))
3647 struct kmem_cache
*s
;
3653 down_write(&slub_lock
);
3654 s
= find_mergeable(size
, align
, flags
, name
, ctor
);
3658 * Adjust the object sizes so that we clear
3659 * the complete object on kzalloc.
3661 s
->objsize
= max(s
->objsize
, (int)size
);
3662 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
3664 if (sysfs_slab_alias(s
, name
)) {
3668 up_write(&slub_lock
);
3672 n
= kstrdup(name
, GFP_KERNEL
);
3676 s
= kmalloc(kmem_size
, GFP_KERNEL
);
3678 if (kmem_cache_open(s
, n
,
3679 size
, align
, flags
, ctor
)) {
3680 list_add(&s
->list
, &slab_caches
);
3681 if (sysfs_slab_add(s
)) {
3687 up_write(&slub_lock
);
3694 up_write(&slub_lock
);
3696 if (flags
& SLAB_PANIC
)
3697 panic("Cannot create slabcache %s\n", name
);
3702 EXPORT_SYMBOL(kmem_cache_create
);
3706 * Use the cpu notifier to insure that the cpu slabs are flushed when
3709 static int __cpuinit
slab_cpuup_callback(struct notifier_block
*nfb
,
3710 unsigned long action
, void *hcpu
)
3712 long cpu
= (long)hcpu
;
3713 struct kmem_cache
*s
;
3714 unsigned long flags
;
3717 case CPU_UP_CANCELED
:
3718 case CPU_UP_CANCELED_FROZEN
:
3720 case CPU_DEAD_FROZEN
:
3721 down_read(&slub_lock
);
3722 list_for_each_entry(s
, &slab_caches
, list
) {
3723 local_irq_save(flags
);
3724 __flush_cpu_slab(s
, cpu
);
3725 local_irq_restore(flags
);
3727 up_read(&slub_lock
);
3735 static struct notifier_block __cpuinitdata slab_notifier
= {
3736 .notifier_call
= slab_cpuup_callback
3741 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, unsigned long caller
)
3743 struct kmem_cache
*s
;
3746 if (unlikely(size
> SLUB_MAX_SIZE
))
3747 return kmalloc_large(size
, gfpflags
);
3749 s
= get_slab(size
, gfpflags
);
3751 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3754 ret
= slab_alloc(s
, gfpflags
, NUMA_NO_NODE
, caller
);
3756 /* Honor the call site pointer we received. */
3757 trace_kmalloc(caller
, ret
, size
, s
->size
, gfpflags
);
3763 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
3764 int node
, unsigned long caller
)
3766 struct kmem_cache
*s
;
3769 if (unlikely(size
> SLUB_MAX_SIZE
)) {
3770 ret
= kmalloc_large_node(size
, gfpflags
, node
);
3772 trace_kmalloc_node(caller
, ret
,
3773 size
, PAGE_SIZE
<< get_order(size
),
3779 s
= get_slab(size
, gfpflags
);
3781 if (unlikely(ZERO_OR_NULL_PTR(s
)))
3784 ret
= slab_alloc(s
, gfpflags
, node
, caller
);
3786 /* Honor the call site pointer we received. */
3787 trace_kmalloc_node(caller
, ret
, size
, s
->size
, gfpflags
, node
);
3794 static int count_inuse(struct page
*page
)
3799 static int count_total(struct page
*page
)
3801 return page
->objects
;
3805 #ifdef CONFIG_SLUB_DEBUG
3806 static int validate_slab(struct kmem_cache
*s
, struct page
*page
,
3810 void *addr
= page_address(page
);
3812 if (!check_slab(s
, page
) ||
3813 !on_freelist(s
, page
, NULL
))
3816 /* Now we know that a valid freelist exists */
3817 bitmap_zero(map
, page
->objects
);
3819 get_map(s
, page
, map
);
3820 for_each_object(p
, s
, addr
, page
->objects
) {
3821 if (test_bit(slab_index(p
, s
, addr
), map
))
3822 if (!check_object(s
, page
, p
, SLUB_RED_INACTIVE
))
3826 for_each_object(p
, s
, addr
, page
->objects
)
3827 if (!test_bit(slab_index(p
, s
, addr
), map
))
3828 if (!check_object(s
, page
, p
, SLUB_RED_ACTIVE
))
3833 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
,
3837 validate_slab(s
, page
, map
);
3841 static int validate_slab_node(struct kmem_cache
*s
,
3842 struct kmem_cache_node
*n
, unsigned long *map
)
3844 unsigned long count
= 0;
3846 unsigned long flags
;
3848 spin_lock_irqsave(&n
->list_lock
, flags
);
3850 list_for_each_entry(page
, &n
->partial
, lru
) {
3851 validate_slab_slab(s
, page
, map
);
3854 if (count
!= n
->nr_partial
)
3855 printk(KERN_ERR
"SLUB %s: %ld partial slabs counted but "
3856 "counter=%ld\n", s
->name
, count
, n
->nr_partial
);
3858 if (!(s
->flags
& SLAB_STORE_USER
))
3861 list_for_each_entry(page
, &n
->full
, lru
) {
3862 validate_slab_slab(s
, page
, map
);
3865 if (count
!= atomic_long_read(&n
->nr_slabs
))
3866 printk(KERN_ERR
"SLUB: %s %ld slabs counted but "
3867 "counter=%ld\n", s
->name
, count
,
3868 atomic_long_read(&n
->nr_slabs
));
3871 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3875 static long validate_slab_cache(struct kmem_cache
*s
)
3878 unsigned long count
= 0;
3879 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
3880 sizeof(unsigned long), GFP_KERNEL
);
3886 for_each_node_state(node
, N_NORMAL_MEMORY
) {
3887 struct kmem_cache_node
*n
= get_node(s
, node
);
3889 count
+= validate_slab_node(s
, n
, map
);
3895 * Generate lists of code addresses where slabcache objects are allocated
3900 unsigned long count
;
3907 DECLARE_BITMAP(cpus
, NR_CPUS
);
3913 unsigned long count
;
3914 struct location
*loc
;
3917 static void free_loc_track(struct loc_track
*t
)
3920 free_pages((unsigned long)t
->loc
,
3921 get_order(sizeof(struct location
) * t
->max
));
3924 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
3929 order
= get_order(sizeof(struct location
) * max
);
3931 l
= (void *)__get_free_pages(flags
, order
);
3936 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
3944 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
3945 const struct track
*track
)
3947 long start
, end
, pos
;
3949 unsigned long caddr
;
3950 unsigned long age
= jiffies
- track
->when
;
3956 pos
= start
+ (end
- start
+ 1) / 2;
3959 * There is nothing at "end". If we end up there
3960 * we need to add something to before end.
3965 caddr
= t
->loc
[pos
].addr
;
3966 if (track
->addr
== caddr
) {
3972 if (age
< l
->min_time
)
3974 if (age
> l
->max_time
)
3977 if (track
->pid
< l
->min_pid
)
3978 l
->min_pid
= track
->pid
;
3979 if (track
->pid
> l
->max_pid
)
3980 l
->max_pid
= track
->pid
;
3982 cpumask_set_cpu(track
->cpu
,
3983 to_cpumask(l
->cpus
));
3985 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3989 if (track
->addr
< caddr
)
3996 * Not found. Insert new tracking element.
3998 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
4004 (t
->count
- pos
) * sizeof(struct location
));
4007 l
->addr
= track
->addr
;
4011 l
->min_pid
= track
->pid
;
4012 l
->max_pid
= track
->pid
;
4013 cpumask_clear(to_cpumask(l
->cpus
));
4014 cpumask_set_cpu(track
->cpu
, to_cpumask(l
->cpus
));
4015 nodes_clear(l
->nodes
);
4016 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
4020 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
4021 struct page
*page
, enum track_item alloc
,
4024 void *addr
= page_address(page
);
4027 bitmap_zero(map
, page
->objects
);
4028 get_map(s
, page
, map
);
4030 for_each_object(p
, s
, addr
, page
->objects
)
4031 if (!test_bit(slab_index(p
, s
, addr
), map
))
4032 add_location(t
, s
, get_track(s
, p
, alloc
));
4035 static int list_locations(struct kmem_cache
*s
, char *buf
,
4036 enum track_item alloc
)
4040 struct loc_track t
= { 0, 0, NULL
};
4042 unsigned long *map
= kmalloc(BITS_TO_LONGS(oo_objects(s
->max
)) *
4043 sizeof(unsigned long), GFP_KERNEL
);
4045 if (!map
|| !alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
4048 return sprintf(buf
, "Out of memory\n");
4050 /* Push back cpu slabs */
4053 for_each_node_state(node
, N_NORMAL_MEMORY
) {
4054 struct kmem_cache_node
*n
= get_node(s
, node
);
4055 unsigned long flags
;
4058 if (!atomic_long_read(&n
->nr_slabs
))
4061 spin_lock_irqsave(&n
->list_lock
, flags
);
4062 list_for_each_entry(page
, &n
->partial
, lru
)
4063 process_slab(&t
, s
, page
, alloc
, map
);
4064 list_for_each_entry(page
, &n
->full
, lru
)
4065 process_slab(&t
, s
, page
, alloc
, map
);
4066 spin_unlock_irqrestore(&n
->list_lock
, flags
);
4069 for (i
= 0; i
< t
.count
; i
++) {
4070 struct location
*l
= &t
.loc
[i
];
4072 if (len
> PAGE_SIZE
- KSYM_SYMBOL_LEN
- 100)
4074 len
+= sprintf(buf
+ len
, "%7ld ", l
->count
);
4077 len
+= sprintf(buf
+ len
, "%pS", (void *)l
->addr
);
4079 len
+= sprintf(buf
+ len
, "<not-available>");
4081 if (l
->sum_time
!= l
->min_time
) {
4082 len
+= sprintf(buf
+ len
, " age=%ld/%ld/%ld",
4084 (long)div_u64(l
->sum_time
, l
->count
),
4087 len
+= sprintf(buf
+ len
, " age=%ld",
4090 if (l
->min_pid
!= l
->max_pid
)
4091 len
+= sprintf(buf
+ len
, " pid=%ld-%ld",
4092 l
->min_pid
, l
->max_pid
);
4094 len
+= sprintf(buf
+ len
, " pid=%ld",
4097 if (num_online_cpus() > 1 &&
4098 !cpumask_empty(to_cpumask(l
->cpus
)) &&
4099 len
< PAGE_SIZE
- 60) {
4100 len
+= sprintf(buf
+ len
, " cpus=");
4101 len
+= cpulist_scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4102 to_cpumask(l
->cpus
));
4105 if (nr_online_nodes
> 1 && !nodes_empty(l
->nodes
) &&
4106 len
< PAGE_SIZE
- 60) {
4107 len
+= sprintf(buf
+ len
, " nodes=");
4108 len
+= nodelist_scnprintf(buf
+ len
, PAGE_SIZE
- len
- 50,
4112 len
+= sprintf(buf
+ len
, "\n");
4118 len
+= sprintf(buf
, "No data\n");
4123 #ifdef SLUB_RESILIENCY_TEST
4124 static void resiliency_test(void)
4128 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 16 || SLUB_PAGE_SHIFT
< 10);
4130 printk(KERN_ERR
"SLUB resiliency testing\n");
4131 printk(KERN_ERR
"-----------------------\n");
4132 printk(KERN_ERR
"A. Corruption after allocation\n");
4134 p
= kzalloc(16, GFP_KERNEL
);
4136 printk(KERN_ERR
"\n1. kmalloc-16: Clobber Redzone/next pointer"
4137 " 0x12->0x%p\n\n", p
+ 16);
4139 validate_slab_cache(kmalloc_caches
[4]);
4141 /* Hmmm... The next two are dangerous */
4142 p
= kzalloc(32, GFP_KERNEL
);
4143 p
[32 + sizeof(void *)] = 0x34;
4144 printk(KERN_ERR
"\n2. kmalloc-32: Clobber next pointer/next slab"
4145 " 0x34 -> -0x%p\n", p
);
4147 "If allocated object is overwritten then not detectable\n\n");
4149 validate_slab_cache(kmalloc_caches
[5]);
4150 p
= kzalloc(64, GFP_KERNEL
);
4151 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
4153 printk(KERN_ERR
"\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4156 "If allocated object is overwritten then not detectable\n\n");
4157 validate_slab_cache(kmalloc_caches
[6]);
4159 printk(KERN_ERR
"\nB. Corruption after free\n");
4160 p
= kzalloc(128, GFP_KERNEL
);
4163 printk(KERN_ERR
"1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
4164 validate_slab_cache(kmalloc_caches
[7]);
4166 p
= kzalloc(256, GFP_KERNEL
);
4169 printk(KERN_ERR
"\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4171 validate_slab_cache(kmalloc_caches
[8]);
4173 p
= kzalloc(512, GFP_KERNEL
);
4176 printk(KERN_ERR
"\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
4177 validate_slab_cache(kmalloc_caches
[9]);
4181 static void resiliency_test(void) {};
4186 enum slab_stat_type
{
4187 SL_ALL
, /* All slabs */
4188 SL_PARTIAL
, /* Only partially allocated slabs */
4189 SL_CPU
, /* Only slabs used for cpu caches */
4190 SL_OBJECTS
, /* Determine allocated objects not slabs */
4191 SL_TOTAL
/* Determine object capacity not slabs */
4194 #define SO_ALL (1 << SL_ALL)
4195 #define SO_PARTIAL (1 << SL_PARTIAL)
4196 #define SO_CPU (1 << SL_CPU)
4197 #define SO_OBJECTS (1 << SL_OBJECTS)
4198 #define SO_TOTAL (1 << SL_TOTAL)
4200 static ssize_t
show_slab_objects(struct kmem_cache
*s
,
4201 char *buf
, unsigned long flags
)
4203 unsigned long total
= 0;
4206 unsigned long *nodes
;
4207 unsigned long *per_cpu
;
4209 nodes
= kzalloc(2 * sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
4212 per_cpu
= nodes
+ nr_node_ids
;
4214 if (flags
& SO_CPU
) {
4217 for_each_possible_cpu(cpu
) {
4218 struct kmem_cache_cpu
*c
= per_cpu_ptr(s
->cpu_slab
, cpu
);
4220 if (!c
|| c
->node
< 0)
4224 if (flags
& SO_TOTAL
)
4225 x
= c
->page
->objects
;
4226 else if (flags
& SO_OBJECTS
)
4232 nodes
[c
->node
] += x
;
4238 lock_memory_hotplug();
4239 #ifdef CONFIG_SLUB_DEBUG
4240 if (flags
& SO_ALL
) {
4241 for_each_node_state(node
, N_NORMAL_MEMORY
) {
4242 struct kmem_cache_node
*n
= get_node(s
, node
);
4244 if (flags
& SO_TOTAL
)
4245 x
= atomic_long_read(&n
->total_objects
);
4246 else if (flags
& SO_OBJECTS
)
4247 x
= atomic_long_read(&n
->total_objects
) -
4248 count_partial(n
, count_free
);
4251 x
= atomic_long_read(&n
->nr_slabs
);
4258 if (flags
& SO_PARTIAL
) {
4259 for_each_node_state(node
, N_NORMAL_MEMORY
) {
4260 struct kmem_cache_node
*n
= get_node(s
, node
);
4262 if (flags
& SO_TOTAL
)
4263 x
= count_partial(n
, count_total
);
4264 else if (flags
& SO_OBJECTS
)
4265 x
= count_partial(n
, count_inuse
);
4272 x
= sprintf(buf
, "%lu", total
);
4274 for_each_node_state(node
, N_NORMAL_MEMORY
)
4276 x
+= sprintf(buf
+ x
, " N%d=%lu",
4279 unlock_memory_hotplug();
4281 return x
+ sprintf(buf
+ x
, "\n");
4284 #ifdef CONFIG_SLUB_DEBUG
4285 static int any_slab_objects(struct kmem_cache
*s
)
4289 for_each_online_node(node
) {
4290 struct kmem_cache_node
*n
= get_node(s
, node
);
4295 if (atomic_long_read(&n
->total_objects
))
4302 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4303 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
4305 struct slab_attribute
{
4306 struct attribute attr
;
4307 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
4308 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
4311 #define SLAB_ATTR_RO(_name) \
4312 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
4314 #define SLAB_ATTR(_name) \
4315 static struct slab_attribute _name##_attr = \
4316 __ATTR(_name, 0644, _name##_show, _name##_store)
4318 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
4320 return sprintf(buf
, "%d\n", s
->size
);
4322 SLAB_ATTR_RO(slab_size
);
4324 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
4326 return sprintf(buf
, "%d\n", s
->align
);
4328 SLAB_ATTR_RO(align
);
4330 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
4332 return sprintf(buf
, "%d\n", s
->objsize
);
4334 SLAB_ATTR_RO(object_size
);
4336 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
4338 return sprintf(buf
, "%d\n", oo_objects(s
->oo
));
4340 SLAB_ATTR_RO(objs_per_slab
);
4342 static ssize_t
order_store(struct kmem_cache
*s
,
4343 const char *buf
, size_t length
)
4345 unsigned long order
;
4348 err
= strict_strtoul(buf
, 10, &order
);
4352 if (order
> slub_max_order
|| order
< slub_min_order
)
4355 calculate_sizes(s
, order
);
4359 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
4361 return sprintf(buf
, "%d\n", oo_order(s
->oo
));
4365 static ssize_t
min_partial_show(struct kmem_cache
*s
, char *buf
)
4367 return sprintf(buf
, "%lu\n", s
->min_partial
);
4370 static ssize_t
min_partial_store(struct kmem_cache
*s
, const char *buf
,
4376 err
= strict_strtoul(buf
, 10, &min
);
4380 set_min_partial(s
, min
);
4383 SLAB_ATTR(min_partial
);
4385 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
4389 return sprintf(buf
, "%pS\n", s
->ctor
);
4393 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
4395 return sprintf(buf
, "%d\n", s
->refcount
- 1);
4397 SLAB_ATTR_RO(aliases
);
4399 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
4401 return show_slab_objects(s
, buf
, SO_PARTIAL
);
4403 SLAB_ATTR_RO(partial
);
4405 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
4407 return show_slab_objects(s
, buf
, SO_CPU
);
4409 SLAB_ATTR_RO(cpu_slabs
);
4411 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
4413 return show_slab_objects(s
, buf
, SO_ALL
|SO_OBJECTS
);
4415 SLAB_ATTR_RO(objects
);
4417 static ssize_t
objects_partial_show(struct kmem_cache
*s
, char *buf
)
4419 return show_slab_objects(s
, buf
, SO_PARTIAL
|SO_OBJECTS
);
4421 SLAB_ATTR_RO(objects_partial
);
4423 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
4425 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
4428 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
4429 const char *buf
, size_t length
)
4431 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
4433 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
4436 SLAB_ATTR(reclaim_account
);
4438 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
4440 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
4442 SLAB_ATTR_RO(hwcache_align
);
4444 #ifdef CONFIG_ZONE_DMA
4445 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
4447 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
4449 SLAB_ATTR_RO(cache_dma
);
4452 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
4454 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
4456 SLAB_ATTR_RO(destroy_by_rcu
);
4458 static ssize_t
reserved_show(struct kmem_cache
*s
, char *buf
)
4460 return sprintf(buf
, "%d\n", s
->reserved
);
4462 SLAB_ATTR_RO(reserved
);
4464 #ifdef CONFIG_SLUB_DEBUG
4465 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
4467 return show_slab_objects(s
, buf
, SO_ALL
);
4469 SLAB_ATTR_RO(slabs
);
4471 static ssize_t
total_objects_show(struct kmem_cache
*s
, char *buf
)
4473 return show_slab_objects(s
, buf
, SO_ALL
|SO_TOTAL
);
4475 SLAB_ATTR_RO(total_objects
);
4477 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
4479 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
4482 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
4483 const char *buf
, size_t length
)
4485 s
->flags
&= ~SLAB_DEBUG_FREE
;
4486 if (buf
[0] == '1') {
4487 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4488 s
->flags
|= SLAB_DEBUG_FREE
;
4492 SLAB_ATTR(sanity_checks
);
4494 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
4496 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
4499 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
4502 s
->flags
&= ~SLAB_TRACE
;
4503 if (buf
[0] == '1') {
4504 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4505 s
->flags
|= SLAB_TRACE
;
4511 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
4513 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
4516 static ssize_t
red_zone_store(struct kmem_cache
*s
,
4517 const char *buf
, size_t length
)
4519 if (any_slab_objects(s
))
4522 s
->flags
&= ~SLAB_RED_ZONE
;
4523 if (buf
[0] == '1') {
4524 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4525 s
->flags
|= SLAB_RED_ZONE
;
4527 calculate_sizes(s
, -1);
4530 SLAB_ATTR(red_zone
);
4532 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
4534 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
4537 static ssize_t
poison_store(struct kmem_cache
*s
,
4538 const char *buf
, size_t length
)
4540 if (any_slab_objects(s
))
4543 s
->flags
&= ~SLAB_POISON
;
4544 if (buf
[0] == '1') {
4545 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4546 s
->flags
|= SLAB_POISON
;
4548 calculate_sizes(s
, -1);
4553 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
4555 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
4558 static ssize_t
store_user_store(struct kmem_cache
*s
,
4559 const char *buf
, size_t length
)
4561 if (any_slab_objects(s
))
4564 s
->flags
&= ~SLAB_STORE_USER
;
4565 if (buf
[0] == '1') {
4566 s
->flags
&= ~__CMPXCHG_DOUBLE
;
4567 s
->flags
|= SLAB_STORE_USER
;
4569 calculate_sizes(s
, -1);
4572 SLAB_ATTR(store_user
);
4574 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
4579 static ssize_t
validate_store(struct kmem_cache
*s
,
4580 const char *buf
, size_t length
)
4584 if (buf
[0] == '1') {
4585 ret
= validate_slab_cache(s
);
4591 SLAB_ATTR(validate
);
4593 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
4595 if (!(s
->flags
& SLAB_STORE_USER
))
4597 return list_locations(s
, buf
, TRACK_ALLOC
);
4599 SLAB_ATTR_RO(alloc_calls
);
4601 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
4603 if (!(s
->flags
& SLAB_STORE_USER
))
4605 return list_locations(s
, buf
, TRACK_FREE
);
4607 SLAB_ATTR_RO(free_calls
);
4608 #endif /* CONFIG_SLUB_DEBUG */
4610 #ifdef CONFIG_FAILSLAB
4611 static ssize_t
failslab_show(struct kmem_cache
*s
, char *buf
)
4613 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_FAILSLAB
));
4616 static ssize_t
failslab_store(struct kmem_cache
*s
, const char *buf
,
4619 s
->flags
&= ~SLAB_FAILSLAB
;
4621 s
->flags
|= SLAB_FAILSLAB
;
4624 SLAB_ATTR(failslab
);
4627 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
4632 static ssize_t
shrink_store(struct kmem_cache
*s
,
4633 const char *buf
, size_t length
)
4635 if (buf
[0] == '1') {
4636 int rc
= kmem_cache_shrink(s
);
4647 static ssize_t
remote_node_defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
4649 return sprintf(buf
, "%d\n", s
->remote_node_defrag_ratio
/ 10);
4652 static ssize_t
remote_node_defrag_ratio_store(struct kmem_cache
*s
,
4653 const char *buf
, size_t length
)
4655 unsigned long ratio
;
4658 err
= strict_strtoul(buf
, 10, &ratio
);
4663 s
->remote_node_defrag_ratio
= ratio
* 10;
4667 SLAB_ATTR(remote_node_defrag_ratio
);
4670 #ifdef CONFIG_SLUB_STATS
4671 static int show_stat(struct kmem_cache
*s
, char *buf
, enum stat_item si
)
4673 unsigned long sum
= 0;
4676 int *data
= kmalloc(nr_cpu_ids
* sizeof(int), GFP_KERNEL
);
4681 for_each_online_cpu(cpu
) {
4682 unsigned x
= per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
];
4688 len
= sprintf(buf
, "%lu", sum
);
4691 for_each_online_cpu(cpu
) {
4692 if (data
[cpu
] && len
< PAGE_SIZE
- 20)
4693 len
+= sprintf(buf
+ len
, " C%d=%u", cpu
, data
[cpu
]);
4697 return len
+ sprintf(buf
+ len
, "\n");
4700 static void clear_stat(struct kmem_cache
*s
, enum stat_item si
)
4704 for_each_online_cpu(cpu
)
4705 per_cpu_ptr(s
->cpu_slab
, cpu
)->stat
[si
] = 0;
4708 #define STAT_ATTR(si, text) \
4709 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4711 return show_stat(s, buf, si); \
4713 static ssize_t text##_store(struct kmem_cache *s, \
4714 const char *buf, size_t length) \
4716 if (buf[0] != '0') \
4718 clear_stat(s, si); \
4723 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4724 STAT_ATTR(ALLOC_SLOWPATH
, alloc_slowpath
);
4725 STAT_ATTR(FREE_FASTPATH
, free_fastpath
);
4726 STAT_ATTR(FREE_SLOWPATH
, free_slowpath
);
4727 STAT_ATTR(FREE_FROZEN
, free_frozen
);
4728 STAT_ATTR(FREE_ADD_PARTIAL
, free_add_partial
);
4729 STAT_ATTR(FREE_REMOVE_PARTIAL
, free_remove_partial
);
4730 STAT_ATTR(ALLOC_FROM_PARTIAL
, alloc_from_partial
);
4731 STAT_ATTR(ALLOC_SLAB
, alloc_slab
);
4732 STAT_ATTR(ALLOC_REFILL
, alloc_refill
);
4733 STAT_ATTR(ALLOC_NODE_MISMATCH
, alloc_node_mismatch
);
4734 STAT_ATTR(FREE_SLAB
, free_slab
);
4735 STAT_ATTR(CPUSLAB_FLUSH
, cpuslab_flush
);
4736 STAT_ATTR(DEACTIVATE_FULL
, deactivate_full
);
4737 STAT_ATTR(DEACTIVATE_EMPTY
, deactivate_empty
);
4738 STAT_ATTR(DEACTIVATE_TO_HEAD
, deactivate_to_head
);
4739 STAT_ATTR(DEACTIVATE_TO_TAIL
, deactivate_to_tail
);
4740 STAT_ATTR(DEACTIVATE_REMOTE_FREES
, deactivate_remote_frees
);
4741 STAT_ATTR(DEACTIVATE_BYPASS
, deactivate_bypass
);
4742 STAT_ATTR(ORDER_FALLBACK
, order_fallback
);
4743 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL
, cmpxchg_double_cpu_fail
);
4744 STAT_ATTR(CMPXCHG_DOUBLE_FAIL
, cmpxchg_double_fail
);
4747 static struct attribute
*slab_attrs
[] = {
4748 &slab_size_attr
.attr
,
4749 &object_size_attr
.attr
,
4750 &objs_per_slab_attr
.attr
,
4752 &min_partial_attr
.attr
,
4754 &objects_partial_attr
.attr
,
4756 &cpu_slabs_attr
.attr
,
4760 &hwcache_align_attr
.attr
,
4761 &reclaim_account_attr
.attr
,
4762 &destroy_by_rcu_attr
.attr
,
4764 &reserved_attr
.attr
,
4765 #ifdef CONFIG_SLUB_DEBUG
4766 &total_objects_attr
.attr
,
4768 &sanity_checks_attr
.attr
,
4770 &red_zone_attr
.attr
,
4772 &store_user_attr
.attr
,
4773 &validate_attr
.attr
,
4774 &alloc_calls_attr
.attr
,
4775 &free_calls_attr
.attr
,
4777 #ifdef CONFIG_ZONE_DMA
4778 &cache_dma_attr
.attr
,
4781 &remote_node_defrag_ratio_attr
.attr
,
4783 #ifdef CONFIG_SLUB_STATS
4784 &alloc_fastpath_attr
.attr
,
4785 &alloc_slowpath_attr
.attr
,
4786 &free_fastpath_attr
.attr
,
4787 &free_slowpath_attr
.attr
,
4788 &free_frozen_attr
.attr
,
4789 &free_add_partial_attr
.attr
,
4790 &free_remove_partial_attr
.attr
,
4791 &alloc_from_partial_attr
.attr
,
4792 &alloc_slab_attr
.attr
,
4793 &alloc_refill_attr
.attr
,
4794 &alloc_node_mismatch_attr
.attr
,
4795 &free_slab_attr
.attr
,
4796 &cpuslab_flush_attr
.attr
,
4797 &deactivate_full_attr
.attr
,
4798 &deactivate_empty_attr
.attr
,
4799 &deactivate_to_head_attr
.attr
,
4800 &deactivate_to_tail_attr
.attr
,
4801 &deactivate_remote_frees_attr
.attr
,
4802 &deactivate_bypass_attr
.attr
,
4803 &order_fallback_attr
.attr
,
4804 &cmpxchg_double_fail_attr
.attr
,
4805 &cmpxchg_double_cpu_fail_attr
.attr
,
4807 #ifdef CONFIG_FAILSLAB
4808 &failslab_attr
.attr
,
4814 static struct attribute_group slab_attr_group
= {
4815 .attrs
= slab_attrs
,
4818 static ssize_t
slab_attr_show(struct kobject
*kobj
,
4819 struct attribute
*attr
,
4822 struct slab_attribute
*attribute
;
4823 struct kmem_cache
*s
;
4826 attribute
= to_slab_attr(attr
);
4829 if (!attribute
->show
)
4832 err
= attribute
->show(s
, buf
);
4837 static ssize_t
slab_attr_store(struct kobject
*kobj
,
4838 struct attribute
*attr
,
4839 const char *buf
, size_t len
)
4841 struct slab_attribute
*attribute
;
4842 struct kmem_cache
*s
;
4845 attribute
= to_slab_attr(attr
);
4848 if (!attribute
->store
)
4851 err
= attribute
->store(s
, buf
, len
);
4856 static void kmem_cache_release(struct kobject
*kobj
)
4858 struct kmem_cache
*s
= to_slab(kobj
);
4864 static const struct sysfs_ops slab_sysfs_ops
= {
4865 .show
= slab_attr_show
,
4866 .store
= slab_attr_store
,
4869 static struct kobj_type slab_ktype
= {
4870 .sysfs_ops
= &slab_sysfs_ops
,
4871 .release
= kmem_cache_release
4874 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
4876 struct kobj_type
*ktype
= get_ktype(kobj
);
4878 if (ktype
== &slab_ktype
)
4883 static const struct kset_uevent_ops slab_uevent_ops
= {
4884 .filter
= uevent_filter
,
4887 static struct kset
*slab_kset
;
4889 #define ID_STR_LENGTH 64
4891 /* Create a unique string id for a slab cache:
4893 * Format :[flags-]size
4895 static char *create_unique_id(struct kmem_cache
*s
)
4897 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
4904 * First flags affecting slabcache operations. We will only
4905 * get here for aliasable slabs so we do not need to support
4906 * too many flags. The flags here must cover all flags that
4907 * are matched during merging to guarantee that the id is
4910 if (s
->flags
& SLAB_CACHE_DMA
)
4912 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
4914 if (s
->flags
& SLAB_DEBUG_FREE
)
4916 if (!(s
->flags
& SLAB_NOTRACK
))
4920 p
+= sprintf(p
, "%07d", s
->size
);
4921 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
4925 static int sysfs_slab_add(struct kmem_cache
*s
)
4931 if (slab_state
< SYSFS
)
4932 /* Defer until later */
4935 unmergeable
= slab_unmergeable(s
);
4938 * Slabcache can never be merged so we can use the name proper.
4939 * This is typically the case for debug situations. In that
4940 * case we can catch duplicate names easily.
4942 sysfs_remove_link(&slab_kset
->kobj
, s
->name
);
4946 * Create a unique name for the slab as a target
4949 name
= create_unique_id(s
);
4952 s
->kobj
.kset
= slab_kset
;
4953 err
= kobject_init_and_add(&s
->kobj
, &slab_ktype
, NULL
, name
);
4955 kobject_put(&s
->kobj
);
4959 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
4961 kobject_del(&s
->kobj
);
4962 kobject_put(&s
->kobj
);
4965 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
4967 /* Setup first alias */
4968 sysfs_slab_alias(s
, s
->name
);
4974 static void sysfs_slab_remove(struct kmem_cache
*s
)
4976 if (slab_state
< SYSFS
)
4978 * Sysfs has not been setup yet so no need to remove the
4983 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
4984 kobject_del(&s
->kobj
);
4985 kobject_put(&s
->kobj
);
4989 * Need to buffer aliases during bootup until sysfs becomes
4990 * available lest we lose that information.
4992 struct saved_alias
{
4993 struct kmem_cache
*s
;
4995 struct saved_alias
*next
;
4998 static struct saved_alias
*alias_list
;
5000 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
5002 struct saved_alias
*al
;
5004 if (slab_state
== SYSFS
) {
5006 * If we have a leftover link then remove it.
5008 sysfs_remove_link(&slab_kset
->kobj
, name
);
5009 return sysfs_create_link(&slab_kset
->kobj
, &s
->kobj
, name
);
5012 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
5018 al
->next
= alias_list
;
5023 static int __init
slab_sysfs_init(void)
5025 struct kmem_cache
*s
;
5028 down_write(&slub_lock
);
5030 slab_kset
= kset_create_and_add("slab", &slab_uevent_ops
, kernel_kobj
);
5032 up_write(&slub_lock
);
5033 printk(KERN_ERR
"Cannot register slab subsystem.\n");
5039 list_for_each_entry(s
, &slab_caches
, list
) {
5040 err
= sysfs_slab_add(s
);
5042 printk(KERN_ERR
"SLUB: Unable to add boot slab %s"
5043 " to sysfs\n", s
->name
);
5046 while (alias_list
) {
5047 struct saved_alias
*al
= alias_list
;
5049 alias_list
= alias_list
->next
;
5050 err
= sysfs_slab_alias(al
->s
, al
->name
);
5052 printk(KERN_ERR
"SLUB: Unable to add boot slab alias"
5053 " %s to sysfs\n", s
->name
);
5057 up_write(&slub_lock
);
5062 __initcall(slab_sysfs_init
);
5063 #endif /* CONFIG_SYSFS */
5066 * The /proc/slabinfo ABI
5068 #ifdef CONFIG_SLABINFO
5069 static void print_slabinfo_header(struct seq_file
*m
)
5071 seq_puts(m
, "slabinfo - version: 2.1\n");
5072 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
5073 "<objperslab> <pagesperslab>");
5074 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
5075 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
5079 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
5083 down_read(&slub_lock
);
5085 print_slabinfo_header(m
);
5087 return seq_list_start(&slab_caches
, *pos
);
5090 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
5092 return seq_list_next(p
, &slab_caches
, pos
);
5095 static void s_stop(struct seq_file
*m
, void *p
)
5097 up_read(&slub_lock
);
5100 static int s_show(struct seq_file
*m
, void *p
)
5102 unsigned long nr_partials
= 0;
5103 unsigned long nr_slabs
= 0;
5104 unsigned long nr_inuse
= 0;
5105 unsigned long nr_objs
= 0;
5106 unsigned long nr_free
= 0;
5107 struct kmem_cache
*s
;
5110 s
= list_entry(p
, struct kmem_cache
, list
);
5112 for_each_online_node(node
) {
5113 struct kmem_cache_node
*n
= get_node(s
, node
);
5118 nr_partials
+= n
->nr_partial
;
5119 nr_slabs
+= atomic_long_read(&n
->nr_slabs
);
5120 nr_objs
+= atomic_long_read(&n
->total_objects
);
5121 nr_free
+= count_partial(n
, count_free
);
5124 nr_inuse
= nr_objs
- nr_free
;
5126 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d", s
->name
, nr_inuse
,
5127 nr_objs
, s
->size
, oo_objects(s
->oo
),
5128 (1 << oo_order(s
->oo
)));
5129 seq_printf(m
, " : tunables %4u %4u %4u", 0, 0, 0);
5130 seq_printf(m
, " : slabdata %6lu %6lu %6lu", nr_slabs
, nr_slabs
,
5136 static const struct seq_operations slabinfo_op
= {
5143 static int slabinfo_open(struct inode
*inode
, struct file
*file
)
5145 return seq_open(file
, &slabinfo_op
);
5148 static const struct file_operations proc_slabinfo_operations
= {
5149 .open
= slabinfo_open
,
5151 .llseek
= seq_lseek
,
5152 .release
= seq_release
,
5155 static int __init
slab_proc_init(void)
5157 proc_create("slabinfo", S_IRUGO
, NULL
, &proc_slabinfo_operations
);
5160 module_init(slab_proc_init
);
5161 #endif /* CONFIG_SLABINFO */