2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
5 * The allocator synchronizes using per slab locks and only
6 * uses a centralized lock to manage a pool of partial slabs.
8 * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
12 #include <linux/module.h>
13 #include <linux/bit_spinlock.h>
14 #include <linux/interrupt.h>
15 #include <linux/bitops.h>
16 #include <linux/slab.h>
17 #include <linux/seq_file.h>
18 #include <linux/cpu.h>
19 #include <linux/cpuset.h>
20 #include <linux/mempolicy.h>
21 #include <linux/ctype.h>
22 #include <linux/kallsyms.h>
23 #include <linux/memory.h>
30 * The slab_lock protects operations on the object of a particular
31 * slab and its metadata in the page struct. If the slab lock
32 * has been taken then no allocations nor frees can be performed
33 * on the objects in the slab nor can the slab be added or removed
34 * from the partial or full lists since this would mean modifying
35 * the page_struct of the slab.
37 * The list_lock protects the partial and full list on each node and
38 * the partial slab counter. If taken then no new slabs may be added or
39 * removed from the lists nor make the number of partial slabs be modified.
40 * (Note that the total number of slabs is an atomic value that may be
41 * modified without taking the list lock).
43 * The list_lock is a centralized lock and thus we avoid taking it as
44 * much as possible. As long as SLUB does not have to handle partial
45 * slabs, operations can continue without any centralized lock. F.e.
46 * allocating a long series of objects that fill up slabs does not require
49 * The lock order is sometimes inverted when we are trying to get a slab
50 * off a list. We take the list_lock and then look for a page on the list
51 * to use. While we do that objects in the slabs may be freed. We can
52 * only operate on the slab if we have also taken the slab_lock. So we use
53 * a slab_trylock() on the slab. If trylock was successful then no frees
54 * can occur anymore and we can use the slab for allocations etc. If the
55 * slab_trylock() does not succeed then frees are in progress in the slab and
56 * we must stay away from it for a while since we may cause a bouncing
57 * cacheline if we try to acquire the lock. So go onto the next slab.
58 * If all pages are busy then we may allocate a new slab instead of reusing
59 * a partial slab. A new slab has noone operating on it and thus there is
60 * no danger of cacheline contention.
62 * Interrupts are disabled during allocation and deallocation in order to
63 * make the slab allocator safe to use in the context of an irq. In addition
64 * interrupts are disabled to ensure that the processor does not change
65 * while handling per_cpu slabs, due to kernel preemption.
67 * SLUB assigns one slab for allocation to each processor.
68 * Allocations only occur from these slabs called cpu slabs.
70 * Slabs with free elements are kept on a partial list and during regular
71 * operations no list for full slabs is used. If an object in a full slab is
72 * freed then the slab will show up again on the partial lists.
73 * We track full slabs for debugging purposes though because otherwise we
74 * cannot scan all objects.
76 * Slabs are freed when they become empty. Teardown and setup is
77 * minimal so we rely on the page allocators per cpu caches for
78 * fast frees and allocs.
80 * Overloading of page flags that are otherwise used for LRU management.
82 * PageActive The slab is frozen and exempt from list processing.
83 * This means that the slab is dedicated to a purpose
84 * such as satisfying allocations for a specific
85 * processor. Objects may be freed in the slab while
86 * it is frozen but slab_free will then skip the usual
87 * list operations. It is up to the processor holding
88 * the slab to integrate the slab into the slab lists
89 * when the slab is no longer needed.
91 * One use of this flag is to mark slabs that are
92 * used for allocations. Then such a slab becomes a cpu
93 * slab. The cpu slab may be equipped with an additional
94 * freelist that allows lockless access to
95 * free objects in addition to the regular freelist
96 * that requires the slab lock.
98 * PageError Slab requires special handling due to debug
99 * options set. This moves slab handling out of
100 * the fast path and disables lockless freelists.
103 #define FROZEN (1 << PG_active)
105 #ifdef CONFIG_SLUB_DEBUG
106 #define SLABDEBUG (1 << PG_error)
111 static inline int SlabFrozen(struct page *page)
113 return page->flags & FROZEN;
116 static inline void SetSlabFrozen(struct page *page)
118 page->flags |= FROZEN;
121 static inline void ClearSlabFrozen(struct page *page)
123 page->flags &= ~FROZEN;
126 static inline int SlabDebug(struct page *page)
128 return page->flags & SLABDEBUG;
131 static inline void SetSlabDebug(struct page *page)
133 page->flags |= SLABDEBUG;
136 static inline void ClearSlabDebug(struct page *page)
138 page->flags &= ~SLABDEBUG;
142 * Issues still to be resolved:
144 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
146 * - Variable sizing of the per node arrays
149 /* Enable to test recovery from slab corruption on boot */
150 #undef SLUB_RESILIENCY_TEST
155 * Small page size. Make sure that we do not fragment memory
157 #define DEFAULT_MAX_ORDER 1
158 #define DEFAULT_MIN_OBJECTS 4
163 * Large page machines are customarily able to handle larger
166 #define DEFAULT_MAX_ORDER 2
167 #define DEFAULT_MIN_OBJECTS 8
172 * Mininum number of partial slabs. These will be left on the partial
173 * lists even if they are empty. kmem_cache_shrink may reclaim them.
175 #define MIN_PARTIAL 5
178 * Maximum number of desirable partial slabs.
179 * The existence of more partial slabs makes kmem_cache_shrink
180 * sort the partial list by the number of objects in the.
182 #define MAX_PARTIAL 10
184 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
185 SLAB_POISON | SLAB_STORE_USER)
188 * Set of flags that will prevent slab merging
190 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
191 SLAB_TRACE | SLAB_DESTROY_BY_RCU)
193 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
196 #ifndef ARCH_KMALLOC_MINALIGN
197 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
200 #ifndef ARCH_SLAB_MINALIGN
201 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
204 /* Internal SLUB flags */
205 #define __OBJECT_POISON 0x80000000 /* Poison object */
206 #define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */
207 #define __KMALLOC_CACHE 0x20000000 /* objects freed using kfree */
208 #define __PAGE_ALLOC_FALLBACK 0x10000000 /* Allow fallback to page alloc */
210 /* Not all arches define cache_line_size */
211 #ifndef cache_line_size
212 #define cache_line_size() L1_CACHE_BYTES
215 static int kmem_size = sizeof(struct kmem_cache);
218 static struct notifier_block slab_notifier;
222 DOWN, /* No slab functionality available */
223 PARTIAL, /* kmem_cache_open() works but kmalloc does not */
224 UP, /* Everything works but does not show up in sysfs */
228 /* A list of all slab caches on the system */
229 static DECLARE_RWSEM(slub_lock);
230 static LIST_HEAD(slab_caches);
233 * Tracking user of a slab.
236 void *addr; /* Called from address */
237 int cpu; /* Was running on cpu */
238 int pid; /* Pid context */
239 unsigned long when; /* When did the operation occur */
242 enum track_item { TRACK_ALLOC, TRACK_FREE };
244 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
245 static int sysfs_slab_add(struct kmem_cache *);
246 static int sysfs_slab_alias(struct kmem_cache *, const char *);
247 static void sysfs_slab_remove(struct kmem_cache *);
250 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
251 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
253 static inline void sysfs_slab_remove(struct kmem_cache *s)
260 static inline void stat(struct kmem_cache_cpu *c, enum stat_item si)
262 #ifdef CONFIG_SLUB_STATS
267 /********************************************************************
268 * Core slab cache functions
269 *******************************************************************/
271 int slab_is_available(void)
273 return slab_state >= UP;
276 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
279 return s->node[node];
281 return &s->local_node;
285 static inline struct kmem_cache_cpu *get_cpu_slab(struct kmem_cache *s, int cpu)
288 return s->cpu_slab[cpu];
294 /* Verify that a pointer has an address that is valid within a slab page */
295 static inline int check_valid_pointer(struct kmem_cache *s,
296 struct page *page, const void *object)
303 base = page_address(page);
304 if (object < base || object >= base + page->objects * s->size ||
305 (object - base) % s->size) {
313 * Slow version of get and set free pointer.
315 * This version requires touching the cache lines of kmem_cache which
316 * we avoid to do in the fast alloc free paths. There we obtain the offset
317 * from the page struct.
319 static inline void *get_freepointer(struct kmem_cache *s, void *object)
321 return *(void **)(object + s->offset);
324 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
326 *(void **)(object + s->offset) = fp;
329 /* Loop over all objects in a slab */
330 #define for_each_object(__p, __s, __addr, __objects) \
331 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
335 #define for_each_free_object(__p, __s, __free) \
336 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
338 /* Determine object index from a given position */
339 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
341 return (p - addr) / s->size;
344 #ifdef CONFIG_SLUB_DEBUG
348 #ifdef CONFIG_SLUB_DEBUG_ON
349 static int slub_debug = DEBUG_DEFAULT_FLAGS;
351 static int slub_debug;
354 static char *slub_debug_slabs;
359 static void print_section(char *text, u8 *addr, unsigned int length)
367 for (i = 0; i < length; i++) {
369 printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
372 printk(KERN_CONT " %02x", addr[i]);
374 ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
376 printk(KERN_CONT " %s\n", ascii);
383 printk(KERN_CONT " ");
387 printk(KERN_CONT " %s\n", ascii);
391 static struct track *get_track(struct kmem_cache *s, void *object,
392 enum track_item alloc)
397 p = object + s->offset + sizeof(void *);
399 p = object + s->inuse;
404 static void set_track(struct kmem_cache *s, void *object,
405 enum track_item alloc, void *addr)
410 p = object + s->offset + sizeof(void *);
412 p = object + s->inuse;
417 p->cpu = smp_processor_id();
418 p->pid = current ? current->pid : -1;
421 memset(p, 0, sizeof(struct track));
424 static void init_tracking(struct kmem_cache *s, void *object)
426 if (!(s->flags & SLAB_STORE_USER))
429 set_track(s, object, TRACK_FREE, NULL);
430 set_track(s, object, TRACK_ALLOC, NULL);
433 static void print_track(const char *s, struct track *t)
438 printk(KERN_ERR "INFO: %s in ", s);
439 __print_symbol("%s", (unsigned long)t->addr);
440 printk(" age=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid);
443 static void print_tracking(struct kmem_cache *s, void *object)
445 if (!(s->flags & SLAB_STORE_USER))
448 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
449 print_track("Freed", get_track(s, object, TRACK_FREE));
452 static void print_page_info(struct page *page)
454 printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
455 page, page->objects, page->inuse, page->freelist, page->flags);
459 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
465 vsnprintf(buf, sizeof(buf), fmt, args);
467 printk(KERN_ERR "========================================"
468 "=====================================\n");
469 printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
470 printk(KERN_ERR "----------------------------------------"
471 "-------------------------------------\n\n");
474 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
480 vsnprintf(buf, sizeof(buf), fmt, args);
482 printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
485 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
487 unsigned int off; /* Offset of last byte */
488 u8 *addr = page_address(page);
490 print_tracking(s, p);
492 print_page_info(page);
494 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
495 p, p - addr, get_freepointer(s, p));
498 print_section("Bytes b4", p - 16, 16);
500 print_section("Object", p, min(s->objsize, 128));
502 if (s->flags & SLAB_RED_ZONE)
503 print_section("Redzone", p + s->objsize,
504 s->inuse - s->objsize);
507 off = s->offset + sizeof(void *);
511 if (s->flags & SLAB_STORE_USER)
512 off += 2 * sizeof(struct track);
515 /* Beginning of the filler is the free pointer */
516 print_section("Padding", p + off, s->size - off);
521 static void object_err(struct kmem_cache *s, struct page *page,
522 u8 *object, char *reason)
524 slab_bug(s, "%s", reason);
525 print_trailer(s, page, object);
528 static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
534 vsnprintf(buf, sizeof(buf), fmt, args);
536 slab_bug(s, "%s", buf);
537 print_page_info(page);
541 static void init_object(struct kmem_cache *s, void *object, int active)
545 if (s->flags & __OBJECT_POISON) {
546 memset(p, POISON_FREE, s->objsize - 1);
547 p[s->objsize - 1] = POISON_END;
550 if (s->flags & SLAB_RED_ZONE)
551 memset(p + s->objsize,
552 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE,
553 s->inuse - s->objsize);
556 static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
559 if (*start != (u8)value)
567 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
568 void *from, void *to)
570 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
571 memset(from, data, to - from);
574 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
575 u8 *object, char *what,
576 u8 *start, unsigned int value, unsigned int bytes)
581 fault = check_bytes(start, value, bytes);
586 while (end > fault && end[-1] == value)
589 slab_bug(s, "%s overwritten", what);
590 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
591 fault, end - 1, fault[0], value);
592 print_trailer(s, page, object);
594 restore_bytes(s, what, value, fault, end);
602 * Bytes of the object to be managed.
603 * If the freepointer may overlay the object then the free
604 * pointer is the first word of the object.
606 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
609 * object + s->objsize
610 * Padding to reach word boundary. This is also used for Redzoning.
611 * Padding is extended by another word if Redzoning is enabled and
614 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
615 * 0xcc (RED_ACTIVE) for objects in use.
618 * Meta data starts here.
620 * A. Free pointer (if we cannot overwrite object on free)
621 * B. Tracking data for SLAB_STORE_USER
622 * C. Padding to reach required alignment boundary or at mininum
623 * one word if debugging is on to be able to detect writes
624 * before the word boundary.
626 * Padding is done using 0x5a (POISON_INUSE)
629 * Nothing is used beyond s->size.
631 * If slabcaches are merged then the objsize and inuse boundaries are mostly
632 * ignored. And therefore no slab options that rely on these boundaries
633 * may be used with merged slabcaches.
636 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
638 unsigned long off = s->inuse; /* The end of info */
641 /* Freepointer is placed after the object. */
642 off += sizeof(void *);
644 if (s->flags & SLAB_STORE_USER)
645 /* We also have user information there */
646 off += 2 * sizeof(struct track);
651 return check_bytes_and_report(s, page, p, "Object padding",
652 p + off, POISON_INUSE, s->size - off);
655 /* Check the pad bytes at the end of a slab page */
656 static int slab_pad_check(struct kmem_cache *s, struct page *page)
664 if (!(s->flags & SLAB_POISON))
667 start = page_address(page);
668 length = (PAGE_SIZE << s->order);
669 end = start + length;
670 remainder = length % s->size;
674 fault = check_bytes(end - remainder, POISON_INUSE, remainder);
677 while (end > fault && end[-1] == POISON_INUSE)
680 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
681 print_section("Padding", end - remainder, remainder);
683 restore_bytes(s, "slab padding", POISON_INUSE, start, end);
687 static int check_object(struct kmem_cache *s, struct page *page,
688 void *object, int active)
691 u8 *endobject = object + s->objsize;
693 if (s->flags & SLAB_RED_ZONE) {
695 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE;
697 if (!check_bytes_and_report(s, page, object, "Redzone",
698 endobject, red, s->inuse - s->objsize))
701 if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
702 check_bytes_and_report(s, page, p, "Alignment padding",
703 endobject, POISON_INUSE, s->inuse - s->objsize);
707 if (s->flags & SLAB_POISON) {
708 if (!active && (s->flags & __OBJECT_POISON) &&
709 (!check_bytes_and_report(s, page, p, "Poison", p,
710 POISON_FREE, s->objsize - 1) ||
711 !check_bytes_and_report(s, page, p, "Poison",
712 p + s->objsize - 1, POISON_END, 1)))
715 * check_pad_bytes cleans up on its own.
717 check_pad_bytes(s, page, p);
720 if (!s->offset && active)
722 * Object and freepointer overlap. Cannot check
723 * freepointer while object is allocated.
727 /* Check free pointer validity */
728 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
729 object_err(s, page, p, "Freepointer corrupt");
731 * No choice but to zap it and thus loose the remainder
732 * of the free objects in this slab. May cause
733 * another error because the object count is now wrong.
735 set_freepointer(s, p, NULL);
741 static int check_slab(struct kmem_cache *s, struct page *page)
745 VM_BUG_ON(!irqs_disabled());
747 if (!PageSlab(page)) {
748 slab_err(s, page, "Not a valid slab page");
752 maxobj = (PAGE_SIZE << compound_order(page)) / s->size;
753 if (page->objects > maxobj) {
754 slab_err(s, page, "objects %u > max %u",
755 s->name, page->objects, maxobj);
758 if (page->inuse > page->objects) {
759 slab_err(s, page, "inuse %u > max %u",
760 s->name, page->inuse, page->objects);
763 /* Slab_pad_check fixes things up after itself */
764 slab_pad_check(s, page);
769 * Determine if a certain object on a page is on the freelist. Must hold the
770 * slab lock to guarantee that the chains are in a consistent state.
772 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
775 void *fp = page->freelist;
777 unsigned long max_objects;
779 while (fp && nr <= page->objects) {
782 if (!check_valid_pointer(s, page, fp)) {
784 object_err(s, page, object,
785 "Freechain corrupt");
786 set_freepointer(s, object, NULL);
789 slab_err(s, page, "Freepointer corrupt");
790 page->freelist = NULL;
791 page->inuse = page->objects;
792 slab_fix(s, "Freelist cleared");
798 fp = get_freepointer(s, object);
802 max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
803 if (max_objects > 65535)
806 if (page->objects != max_objects) {
807 slab_err(s, page, "Wrong number of objects. Found %d but "
808 "should be %d", page->objects, max_objects);
809 page->objects = max_objects;
810 slab_fix(s, "Number of objects adjusted.");
812 if (page->inuse != page->objects - nr) {
813 slab_err(s, page, "Wrong object count. Counter is %d but "
814 "counted were %d", page->inuse, page->objects - nr);
815 page->inuse = page->objects - nr;
816 slab_fix(s, "Object count adjusted.");
818 return search == NULL;
821 static void trace(struct kmem_cache *s, struct page *page, void *object, int alloc)
823 if (s->flags & SLAB_TRACE) {
824 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
826 alloc ? "alloc" : "free",
831 print_section("Object", (void *)object, s->objsize);
838 * Tracking of fully allocated slabs for debugging purposes.
840 static void add_full(struct kmem_cache_node *n, struct page *page)
842 spin_lock(&n->list_lock);
843 list_add(&page->lru, &n->full);
844 spin_unlock(&n->list_lock);
847 static void remove_full(struct kmem_cache *s, struct page *page)
849 struct kmem_cache_node *n;
851 if (!(s->flags & SLAB_STORE_USER))
854 n = get_node(s, page_to_nid(page));
856 spin_lock(&n->list_lock);
857 list_del(&page->lru);
858 spin_unlock(&n->list_lock);
861 /* Tracking of the number of slabs for debugging purposes */
862 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
864 struct kmem_cache_node *n = get_node(s, node);
866 return atomic_long_read(&n->nr_slabs);
869 static inline void inc_slabs_node(struct kmem_cache *s, int node)
871 struct kmem_cache_node *n = get_node(s, node);
874 * May be called early in order to allocate a slab for the
875 * kmem_cache_node structure. Solve the chicken-egg
876 * dilemma by deferring the increment of the count during
877 * bootstrap (see early_kmem_cache_node_alloc).
879 if (!NUMA_BUILD || n)
880 atomic_long_inc(&n->nr_slabs);
882 static inline void dec_slabs_node(struct kmem_cache *s, int node)
884 struct kmem_cache_node *n = get_node(s, node);
886 atomic_long_dec(&n->nr_slabs);
889 /* Object debug checks for alloc/free paths */
890 static void setup_object_debug(struct kmem_cache *s, struct page *page,
893 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
896 init_object(s, object, 0);
897 init_tracking(s, object);
900 static int alloc_debug_processing(struct kmem_cache *s, struct page *page,
901 void *object, void *addr)
903 if (!check_slab(s, page))
906 if (!on_freelist(s, page, object)) {
907 object_err(s, page, object, "Object already allocated");
911 if (!check_valid_pointer(s, page, object)) {
912 object_err(s, page, object, "Freelist Pointer check fails");
916 if (!check_object(s, page, object, 0))
919 /* Success perform special debug activities for allocs */
920 if (s->flags & SLAB_STORE_USER)
921 set_track(s, object, TRACK_ALLOC, addr);
922 trace(s, page, object, 1);
923 init_object(s, object, 1);
927 if (PageSlab(page)) {
929 * If this is a slab page then lets do the best we can
930 * to avoid issues in the future. Marking all objects
931 * as used avoids touching the remaining objects.
933 slab_fix(s, "Marking all objects used");
934 page->inuse = page->objects;
935 page->freelist = NULL;
940 static int free_debug_processing(struct kmem_cache *s, struct page *page,
941 void *object, void *addr)
943 if (!check_slab(s, page))
946 if (!check_valid_pointer(s, page, object)) {
947 slab_err(s, page, "Invalid object pointer 0x%p", object);
951 if (on_freelist(s, page, object)) {
952 object_err(s, page, object, "Object already free");
956 if (!check_object(s, page, object, 1))
959 if (unlikely(s != page->slab)) {
960 if (!PageSlab(page)) {
961 slab_err(s, page, "Attempt to free object(0x%p) "
962 "outside of slab", object);
963 } else if (!page->slab) {
965 "SLUB <none>: no slab for object 0x%p.\n",
969 object_err(s, page, object,
970 "page slab pointer corrupt.");
974 /* Special debug activities for freeing objects */
975 if (!SlabFrozen(page) && !page->freelist)
976 remove_full(s, page);
977 if (s->flags & SLAB_STORE_USER)
978 set_track(s, object, TRACK_FREE, addr);
979 trace(s, page, object, 0);
980 init_object(s, object, 0);
984 slab_fix(s, "Object at 0x%p not freed", object);
988 static int __init setup_slub_debug(char *str)
990 slub_debug = DEBUG_DEFAULT_FLAGS;
991 if (*str++ != '=' || !*str)
993 * No options specified. Switch on full debugging.
999 * No options but restriction on slabs. This means full
1000 * debugging for slabs matching a pattern.
1007 * Switch off all debugging measures.
1012 * Determine which debug features should be switched on
1014 for (; *str && *str != ','; str++) {
1015 switch (tolower(*str)) {
1017 slub_debug |= SLAB_DEBUG_FREE;
1020 slub_debug |= SLAB_RED_ZONE;
1023 slub_debug |= SLAB_POISON;
1026 slub_debug |= SLAB_STORE_USER;
1029 slub_debug |= SLAB_TRACE;
1032 printk(KERN_ERR "slub_debug option '%c' "
1033 "unknown. skipped\n", *str);
1039 slub_debug_slabs = str + 1;
1044 __setup("slub_debug", setup_slub_debug);
1046 static unsigned long kmem_cache_flags(unsigned long objsize,
1047 unsigned long flags, const char *name,
1048 void (*ctor)(struct kmem_cache *, void *))
1051 * Enable debugging if selected on the kernel commandline.
1053 if (slub_debug && (!slub_debug_slabs ||
1054 strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)) == 0))
1055 flags |= slub_debug;
1060 static inline void setup_object_debug(struct kmem_cache *s,
1061 struct page *page, void *object) {}
1063 static inline int alloc_debug_processing(struct kmem_cache *s,
1064 struct page *page, void *object, void *addr) { return 0; }
1066 static inline int free_debug_processing(struct kmem_cache *s,
1067 struct page *page, void *object, void *addr) { return 0; }
1069 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1071 static inline int check_object(struct kmem_cache *s, struct page *page,
1072 void *object, int active) { return 1; }
1073 static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
1074 static inline unsigned long kmem_cache_flags(unsigned long objsize,
1075 unsigned long flags, const char *name,
1076 void (*ctor)(struct kmem_cache *, void *))
1080 #define slub_debug 0
1082 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1084 static inline void inc_slabs_node(struct kmem_cache *s, int node) {}
1085 static inline void dec_slabs_node(struct kmem_cache *s, int node) {}
1088 * Slab allocation and freeing
1090 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1093 int pages = 1 << s->order;
1095 flags |= s->allocflags;
1098 page = alloc_pages(flags, s->order);
1100 page = alloc_pages_node(node, flags, s->order);
1105 page->objects = s->objects;
1106 mod_zone_page_state(page_zone(page),
1107 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1108 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1114 static void setup_object(struct kmem_cache *s, struct page *page,
1117 setup_object_debug(s, page, object);
1118 if (unlikely(s->ctor))
1122 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1129 BUG_ON(flags & GFP_SLAB_BUG_MASK);
1131 page = allocate_slab(s,
1132 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1136 inc_slabs_node(s, page_to_nid(page));
1138 page->flags |= 1 << PG_slab;
1139 if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
1140 SLAB_STORE_USER | SLAB_TRACE))
1143 start = page_address(page);
1145 if (unlikely(s->flags & SLAB_POISON))
1146 memset(start, POISON_INUSE, PAGE_SIZE << s->order);
1149 for_each_object(p, s, start, page->objects) {
1150 setup_object(s, page, last);
1151 set_freepointer(s, last, p);
1154 setup_object(s, page, last);
1155 set_freepointer(s, last, NULL);
1157 page->freelist = start;
1163 static void __free_slab(struct kmem_cache *s, struct page *page)
1165 int pages = 1 << s->order;
1167 if (unlikely(SlabDebug(page))) {
1170 slab_pad_check(s, page);
1171 for_each_object(p, s, page_address(page),
1173 check_object(s, page, p, 0);
1174 ClearSlabDebug(page);
1177 mod_zone_page_state(page_zone(page),
1178 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1179 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1182 __ClearPageSlab(page);
1183 reset_page_mapcount(page);
1184 __free_pages(page, s->order);
1187 static void rcu_free_slab(struct rcu_head *h)
1191 page = container_of((struct list_head *)h, struct page, lru);
1192 __free_slab(page->slab, page);
1195 static void free_slab(struct kmem_cache *s, struct page *page)
1197 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1199 * RCU free overloads the RCU head over the LRU
1201 struct rcu_head *head = (void *)&page->lru;
1203 call_rcu(head, rcu_free_slab);
1205 __free_slab(s, page);
1208 static void discard_slab(struct kmem_cache *s, struct page *page)
1210 dec_slabs_node(s, page_to_nid(page));
1215 * Per slab locking using the pagelock
1217 static __always_inline void slab_lock(struct page *page)
1219 bit_spin_lock(PG_locked, &page->flags);
1222 static __always_inline void slab_unlock(struct page *page)
1224 __bit_spin_unlock(PG_locked, &page->flags);
1227 static __always_inline int slab_trylock(struct page *page)
1231 rc = bit_spin_trylock(PG_locked, &page->flags);
1236 * Management of partially allocated slabs
1238 static void add_partial(struct kmem_cache_node *n,
1239 struct page *page, int tail)
1241 spin_lock(&n->list_lock);
1244 list_add_tail(&page->lru, &n->partial);
1246 list_add(&page->lru, &n->partial);
1247 spin_unlock(&n->list_lock);
1250 static void remove_partial(struct kmem_cache *s,
1253 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1255 spin_lock(&n->list_lock);
1256 list_del(&page->lru);
1258 spin_unlock(&n->list_lock);
1262 * Lock slab and remove from the partial list.
1264 * Must hold list_lock.
1266 static inline int lock_and_freeze_slab(struct kmem_cache_node *n, struct page *page)
1268 if (slab_trylock(page)) {
1269 list_del(&page->lru);
1271 SetSlabFrozen(page);
1278 * Try to allocate a partial slab from a specific node.
1280 static struct page *get_partial_node(struct kmem_cache_node *n)
1285 * Racy check. If we mistakenly see no partial slabs then we
1286 * just allocate an empty slab. If we mistakenly try to get a
1287 * partial slab and there is none available then get_partials()
1290 if (!n || !n->nr_partial)
1293 spin_lock(&n->list_lock);
1294 list_for_each_entry(page, &n->partial, lru)
1295 if (lock_and_freeze_slab(n, page))
1299 spin_unlock(&n->list_lock);
1304 * Get a page from somewhere. Search in increasing NUMA distances.
1306 static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
1309 struct zonelist *zonelist;
1314 * The defrag ratio allows a configuration of the tradeoffs between
1315 * inter node defragmentation and node local allocations. A lower
1316 * defrag_ratio increases the tendency to do local allocations
1317 * instead of attempting to obtain partial slabs from other nodes.
1319 * If the defrag_ratio is set to 0 then kmalloc() always
1320 * returns node local objects. If the ratio is higher then kmalloc()
1321 * may return off node objects because partial slabs are obtained
1322 * from other nodes and filled up.
1324 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1325 * defrag_ratio = 1000) then every (well almost) allocation will
1326 * first attempt to defrag slab caches on other nodes. This means
1327 * scanning over all nodes to look for partial slabs which may be
1328 * expensive if we do it every time we are trying to find a slab
1329 * with available objects.
1331 if (!s->remote_node_defrag_ratio ||
1332 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1335 zonelist = &NODE_DATA(
1336 slab_node(current->mempolicy))->node_zonelists[gfp_zone(flags)];
1337 for (z = zonelist->zones; *z; z++) {
1338 struct kmem_cache_node *n;
1340 n = get_node(s, zone_to_nid(*z));
1342 if (n && cpuset_zone_allowed_hardwall(*z, flags) &&
1343 n->nr_partial > MIN_PARTIAL) {
1344 page = get_partial_node(n);
1354 * Get a partial page, lock it and return it.
1356 static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
1359 int searchnode = (node == -1) ? numa_node_id() : node;
1361 page = get_partial_node(get_node(s, searchnode));
1362 if (page || (flags & __GFP_THISNODE))
1365 return get_any_partial(s, flags);
1369 * Move a page back to the lists.
1371 * Must be called with the slab lock held.
1373 * On exit the slab lock will have been dropped.
1375 static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
1377 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1378 struct kmem_cache_cpu *c = get_cpu_slab(s, smp_processor_id());
1380 ClearSlabFrozen(page);
1383 if (page->freelist) {
1384 add_partial(n, page, tail);
1385 stat(c, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
1387 stat(c, DEACTIVATE_FULL);
1388 if (SlabDebug(page) && (s->flags & SLAB_STORE_USER))
1393 stat(c, DEACTIVATE_EMPTY);
1394 if (n->nr_partial < MIN_PARTIAL) {
1396 * Adding an empty slab to the partial slabs in order
1397 * to avoid page allocator overhead. This slab needs
1398 * to come after the other slabs with objects in
1399 * so that the others get filled first. That way the
1400 * size of the partial list stays small.
1402 * kmem_cache_shrink can reclaim any empty slabs from the
1405 add_partial(n, page, 1);
1409 stat(get_cpu_slab(s, raw_smp_processor_id()), FREE_SLAB);
1410 discard_slab(s, page);
1416 * Remove the cpu slab
1418 static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1420 struct page *page = c->page;
1424 stat(c, DEACTIVATE_REMOTE_FREES);
1426 * Merge cpu freelist into slab freelist. Typically we get here
1427 * because both freelists are empty. So this is unlikely
1430 while (unlikely(c->freelist)) {
1433 tail = 0; /* Hot objects. Put the slab first */
1435 /* Retrieve object from cpu_freelist */
1436 object = c->freelist;
1437 c->freelist = c->freelist[c->offset];
1439 /* And put onto the regular freelist */
1440 object[c->offset] = page->freelist;
1441 page->freelist = object;
1445 unfreeze_slab(s, page, tail);
1448 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1450 stat(c, CPUSLAB_FLUSH);
1452 deactivate_slab(s, c);
1458 * Called from IPI handler with interrupts disabled.
1460 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
1462 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
1464 if (likely(c && c->page))
1468 static void flush_cpu_slab(void *d)
1470 struct kmem_cache *s = d;
1472 __flush_cpu_slab(s, smp_processor_id());
1475 static void flush_all(struct kmem_cache *s)
1478 on_each_cpu(flush_cpu_slab, s, 1, 1);
1480 unsigned long flags;
1482 local_irq_save(flags);
1484 local_irq_restore(flags);
1489 * Check if the objects in a per cpu structure fit numa
1490 * locality expectations.
1492 static inline int node_match(struct kmem_cache_cpu *c, int node)
1495 if (node != -1 && c->node != node)
1502 * Slow path. The lockless freelist is empty or we need to perform
1505 * Interrupts are disabled.
1507 * Processing is still very fast if new objects have been freed to the
1508 * regular freelist. In that case we simply take over the regular freelist
1509 * as the lockless freelist and zap the regular freelist.
1511 * If that is not working then we fall back to the partial lists. We take the
1512 * first element of the freelist as the object to allocate now and move the
1513 * rest of the freelist to the lockless freelist.
1515 * And if we were unable to get a new slab from the partial slab lists then
1516 * we need to allocate a new slab. This is the slowest path since it involves
1517 * a call to the page allocator and the setup of a new slab.
1519 static void *__slab_alloc(struct kmem_cache *s,
1520 gfp_t gfpflags, int node, void *addr, struct kmem_cache_cpu *c)
1525 /* We handle __GFP_ZERO in the caller */
1526 gfpflags &= ~__GFP_ZERO;
1532 if (unlikely(!node_match(c, node)))
1535 stat(c, ALLOC_REFILL);
1538 object = c->page->freelist;
1539 if (unlikely(!object))
1541 if (unlikely(SlabDebug(c->page)))
1544 c->freelist = object[c->offset];
1545 c->page->inuse = c->page->objects;
1546 c->page->freelist = NULL;
1547 c->node = page_to_nid(c->page);
1549 slab_unlock(c->page);
1550 stat(c, ALLOC_SLOWPATH);
1554 deactivate_slab(s, c);
1557 new = get_partial(s, gfpflags, node);
1560 stat(c, ALLOC_FROM_PARTIAL);
1564 if (gfpflags & __GFP_WAIT)
1567 new = new_slab(s, gfpflags, node);
1569 if (gfpflags & __GFP_WAIT)
1570 local_irq_disable();
1573 c = get_cpu_slab(s, smp_processor_id());
1574 stat(c, ALLOC_SLAB);
1584 * No memory available.
1586 * If the slab uses higher order allocs but the object is
1587 * smaller than a page size then we can fallback in emergencies
1588 * to the page allocator via kmalloc_large. The page allocator may
1589 * have failed to obtain a higher order page and we can try to
1590 * allocate a single page if the object fits into a single page.
1591 * That is only possible if certain conditions are met that are being
1592 * checked when a slab is created.
1594 if (!(gfpflags & __GFP_NORETRY) &&
1595 (s->flags & __PAGE_ALLOC_FALLBACK)) {
1596 if (gfpflags & __GFP_WAIT)
1598 object = kmalloc_large(s->objsize, gfpflags);
1599 if (gfpflags & __GFP_WAIT)
1600 local_irq_disable();
1605 if (!alloc_debug_processing(s, c->page, object, addr))
1609 c->page->freelist = object[c->offset];
1615 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1616 * have the fastpath folded into their functions. So no function call
1617 * overhead for requests that can be satisfied on the fastpath.
1619 * The fastpath works by first checking if the lockless freelist can be used.
1620 * If not then __slab_alloc is called for slow processing.
1622 * Otherwise we can simply pick the next object from the lockless free list.
1624 static __always_inline void *slab_alloc(struct kmem_cache *s,
1625 gfp_t gfpflags, int node, void *addr)
1628 struct kmem_cache_cpu *c;
1629 unsigned long flags;
1631 local_irq_save(flags);
1632 c = get_cpu_slab(s, smp_processor_id());
1633 if (unlikely(!c->freelist || !node_match(c, node)))
1635 object = __slab_alloc(s, gfpflags, node, addr, c);
1638 object = c->freelist;
1639 c->freelist = object[c->offset];
1640 stat(c, ALLOC_FASTPATH);
1642 local_irq_restore(flags);
1644 if (unlikely((gfpflags & __GFP_ZERO) && object))
1645 memset(object, 0, c->objsize);
1650 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
1652 return slab_alloc(s, gfpflags, -1, __builtin_return_address(0));
1654 EXPORT_SYMBOL(kmem_cache_alloc);
1657 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
1659 return slab_alloc(s, gfpflags, node, __builtin_return_address(0));
1661 EXPORT_SYMBOL(kmem_cache_alloc_node);
1665 * Slow patch handling. This may still be called frequently since objects
1666 * have a longer lifetime than the cpu slabs in most processing loads.
1668 * So we still attempt to reduce cache line usage. Just take the slab
1669 * lock and free the item. If there is no additional partial page
1670 * handling required then we can return immediately.
1672 static void __slab_free(struct kmem_cache *s, struct page *page,
1673 void *x, void *addr, unsigned int offset)
1676 void **object = (void *)x;
1677 struct kmem_cache_cpu *c;
1679 c = get_cpu_slab(s, raw_smp_processor_id());
1680 stat(c, FREE_SLOWPATH);
1683 if (unlikely(SlabDebug(page)))
1687 prior = object[offset] = page->freelist;
1688 page->freelist = object;
1691 if (unlikely(SlabFrozen(page))) {
1692 stat(c, FREE_FROZEN);
1696 if (unlikely(!page->inuse))
1700 * Objects left in the slab. If it was not on the partial list before
1703 if (unlikely(!prior)) {
1704 add_partial(get_node(s, page_to_nid(page)), page, 1);
1705 stat(c, FREE_ADD_PARTIAL);
1715 * Slab still on the partial list.
1717 remove_partial(s, page);
1718 stat(c, FREE_REMOVE_PARTIAL);
1722 discard_slab(s, page);
1726 if (!free_debug_processing(s, page, x, addr))
1732 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1733 * can perform fastpath freeing without additional function calls.
1735 * The fastpath is only possible if we are freeing to the current cpu slab
1736 * of this processor. This typically the case if we have just allocated
1739 * If fastpath is not possible then fall back to __slab_free where we deal
1740 * with all sorts of special processing.
1742 static __always_inline void slab_free(struct kmem_cache *s,
1743 struct page *page, void *x, void *addr)
1745 void **object = (void *)x;
1746 struct kmem_cache_cpu *c;
1747 unsigned long flags;
1749 local_irq_save(flags);
1750 c = get_cpu_slab(s, smp_processor_id());
1751 debug_check_no_locks_freed(object, c->objsize);
1752 if (likely(page == c->page && c->node >= 0)) {
1753 object[c->offset] = c->freelist;
1754 c->freelist = object;
1755 stat(c, FREE_FASTPATH);
1757 __slab_free(s, page, x, addr, c->offset);
1759 local_irq_restore(flags);
1762 void kmem_cache_free(struct kmem_cache *s, void *x)
1766 page = virt_to_head_page(x);
1768 slab_free(s, page, x, __builtin_return_address(0));
1770 EXPORT_SYMBOL(kmem_cache_free);
1772 /* Figure out on which slab object the object resides */
1773 static struct page *get_object_page(const void *x)
1775 struct page *page = virt_to_head_page(x);
1777 if (!PageSlab(page))
1784 * Object placement in a slab is made very easy because we always start at
1785 * offset 0. If we tune the size of the object to the alignment then we can
1786 * get the required alignment by putting one properly sized object after
1789 * Notice that the allocation order determines the sizes of the per cpu
1790 * caches. Each processor has always one slab available for allocations.
1791 * Increasing the allocation order reduces the number of times that slabs
1792 * must be moved on and off the partial lists and is therefore a factor in
1797 * Mininum / Maximum order of slab pages. This influences locking overhead
1798 * and slab fragmentation. A higher order reduces the number of partial slabs
1799 * and increases the number of allocations possible without having to
1800 * take the list_lock.
1802 static int slub_min_order;
1803 static int slub_max_order = DEFAULT_MAX_ORDER;
1804 static int slub_min_objects = DEFAULT_MIN_OBJECTS;
1807 * Merge control. If this is set then no merging of slab caches will occur.
1808 * (Could be removed. This was introduced to pacify the merge skeptics.)
1810 static int slub_nomerge;
1813 * Calculate the order of allocation given an slab object size.
1815 * The order of allocation has significant impact on performance and other
1816 * system components. Generally order 0 allocations should be preferred since
1817 * order 0 does not cause fragmentation in the page allocator. Larger objects
1818 * be problematic to put into order 0 slabs because there may be too much
1819 * unused space left. We go to a higher order if more than 1/8th of the slab
1822 * In order to reach satisfactory performance we must ensure that a minimum
1823 * number of objects is in one slab. Otherwise we may generate too much
1824 * activity on the partial lists which requires taking the list_lock. This is
1825 * less a concern for large slabs though which are rarely used.
1827 * slub_max_order specifies the order where we begin to stop considering the
1828 * number of objects in a slab as critical. If we reach slub_max_order then
1829 * we try to keep the page order as low as possible. So we accept more waste
1830 * of space in favor of a small page order.
1832 * Higher order allocations also allow the placement of more objects in a
1833 * slab and thereby reduce object handling overhead. If the user has
1834 * requested a higher mininum order then we start with that one instead of
1835 * the smallest order which will fit the object.
1837 static inline int slab_order(int size, int min_objects,
1838 int max_order, int fract_leftover)
1842 int min_order = slub_min_order;
1844 if ((PAGE_SIZE << min_order) / size > 65535)
1845 return get_order(size * 65535) - 1;
1847 for (order = max(min_order,
1848 fls(min_objects * size - 1) - PAGE_SHIFT);
1849 order <= max_order; order++) {
1851 unsigned long slab_size = PAGE_SIZE << order;
1853 if (slab_size < min_objects * size)
1856 rem = slab_size % size;
1858 if (rem <= slab_size / fract_leftover)
1866 static inline int calculate_order(int size)
1873 * Attempt to find best configuration for a slab. This
1874 * works by first attempting to generate a layout with
1875 * the best configuration and backing off gradually.
1877 * First we reduce the acceptable waste in a slab. Then
1878 * we reduce the minimum objects required in a slab.
1880 min_objects = slub_min_objects;
1881 while (min_objects > 1) {
1883 while (fraction >= 4) {
1884 order = slab_order(size, min_objects,
1885 slub_max_order, fraction);
1886 if (order <= slub_max_order)
1894 * We were unable to place multiple objects in a slab. Now
1895 * lets see if we can place a single object there.
1897 order = slab_order(size, 1, slub_max_order, 1);
1898 if (order <= slub_max_order)
1902 * Doh this slab cannot be placed using slub_max_order.
1904 order = slab_order(size, 1, MAX_ORDER, 1);
1905 if (order <= MAX_ORDER)
1911 * Figure out what the alignment of the objects will be.
1913 static unsigned long calculate_alignment(unsigned long flags,
1914 unsigned long align, unsigned long size)
1917 * If the user wants hardware cache aligned objects then follow that
1918 * suggestion if the object is sufficiently large.
1920 * The hardware cache alignment cannot override the specified
1921 * alignment though. If that is greater then use it.
1923 if (flags & SLAB_HWCACHE_ALIGN) {
1924 unsigned long ralign = cache_line_size();
1925 while (size <= ralign / 2)
1927 align = max(align, ralign);
1930 if (align < ARCH_SLAB_MINALIGN)
1931 align = ARCH_SLAB_MINALIGN;
1933 return ALIGN(align, sizeof(void *));
1936 static void init_kmem_cache_cpu(struct kmem_cache *s,
1937 struct kmem_cache_cpu *c)
1942 c->offset = s->offset / sizeof(void *);
1943 c->objsize = s->objsize;
1944 #ifdef CONFIG_SLUB_STATS
1945 memset(c->stat, 0, NR_SLUB_STAT_ITEMS * sizeof(unsigned));
1949 static void init_kmem_cache_node(struct kmem_cache_node *n)
1952 spin_lock_init(&n->list_lock);
1953 INIT_LIST_HEAD(&n->partial);
1954 #ifdef CONFIG_SLUB_DEBUG
1955 atomic_long_set(&n->nr_slabs, 0);
1956 INIT_LIST_HEAD(&n->full);
1962 * Per cpu array for per cpu structures.
1964 * The per cpu array places all kmem_cache_cpu structures from one processor
1965 * close together meaning that it becomes possible that multiple per cpu
1966 * structures are contained in one cacheline. This may be particularly
1967 * beneficial for the kmalloc caches.
1969 * A desktop system typically has around 60-80 slabs. With 100 here we are
1970 * likely able to get per cpu structures for all caches from the array defined
1971 * here. We must be able to cover all kmalloc caches during bootstrap.
1973 * If the per cpu array is exhausted then fall back to kmalloc
1974 * of individual cachelines. No sharing is possible then.
1976 #define NR_KMEM_CACHE_CPU 100
1978 static DEFINE_PER_CPU(struct kmem_cache_cpu,
1979 kmem_cache_cpu)[NR_KMEM_CACHE_CPU];
1981 static DEFINE_PER_CPU(struct kmem_cache_cpu *, kmem_cache_cpu_free);
1982 static cpumask_t kmem_cach_cpu_free_init_once = CPU_MASK_NONE;
1984 static struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s,
1985 int cpu, gfp_t flags)
1987 struct kmem_cache_cpu *c = per_cpu(kmem_cache_cpu_free, cpu);
1990 per_cpu(kmem_cache_cpu_free, cpu) =
1991 (void *)c->freelist;
1993 /* Table overflow: So allocate ourselves */
1995 ALIGN(sizeof(struct kmem_cache_cpu), cache_line_size()),
1996 flags, cpu_to_node(cpu));
2001 init_kmem_cache_cpu(s, c);
2005 static void free_kmem_cache_cpu(struct kmem_cache_cpu *c, int cpu)
2007 if (c < per_cpu(kmem_cache_cpu, cpu) ||
2008 c > per_cpu(kmem_cache_cpu, cpu) + NR_KMEM_CACHE_CPU) {
2012 c->freelist = (void *)per_cpu(kmem_cache_cpu_free, cpu);
2013 per_cpu(kmem_cache_cpu_free, cpu) = c;
2016 static void free_kmem_cache_cpus(struct kmem_cache *s)
2020 for_each_online_cpu(cpu) {
2021 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
2024 s->cpu_slab[cpu] = NULL;
2025 free_kmem_cache_cpu(c, cpu);
2030 static int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
2034 for_each_online_cpu(cpu) {
2035 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
2040 c = alloc_kmem_cache_cpu(s, cpu, flags);
2042 free_kmem_cache_cpus(s);
2045 s->cpu_slab[cpu] = c;
2051 * Initialize the per cpu array.
2053 static void init_alloc_cpu_cpu(int cpu)
2057 if (cpu_isset(cpu, kmem_cach_cpu_free_init_once))
2060 for (i = NR_KMEM_CACHE_CPU - 1; i >= 0; i--)
2061 free_kmem_cache_cpu(&per_cpu(kmem_cache_cpu, cpu)[i], cpu);
2063 cpu_set(cpu, kmem_cach_cpu_free_init_once);
2066 static void __init init_alloc_cpu(void)
2070 for_each_online_cpu(cpu)
2071 init_alloc_cpu_cpu(cpu);
2075 static inline void free_kmem_cache_cpus(struct kmem_cache *s) {}
2076 static inline void init_alloc_cpu(void) {}
2078 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
2080 init_kmem_cache_cpu(s, &s->cpu_slab);
2087 * No kmalloc_node yet so do it by hand. We know that this is the first
2088 * slab on the node for this slabcache. There are no concurrent accesses
2091 * Note that this function only works on the kmalloc_node_cache
2092 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2093 * memory on a fresh node that has no slab structures yet.
2095 static struct kmem_cache_node *early_kmem_cache_node_alloc(gfp_t gfpflags,
2099 struct kmem_cache_node *n;
2100 unsigned long flags;
2102 BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
2104 page = new_slab(kmalloc_caches, gfpflags, node);
2107 if (page_to_nid(page) != node) {
2108 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2110 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2111 "in order to be able to continue\n");
2116 page->freelist = get_freepointer(kmalloc_caches, n);
2118 kmalloc_caches->node[node] = n;
2119 #ifdef CONFIG_SLUB_DEBUG
2120 init_object(kmalloc_caches, n, 1);
2121 init_tracking(kmalloc_caches, n);
2123 init_kmem_cache_node(n);
2124 inc_slabs_node(kmalloc_caches, node);
2127 * lockdep requires consistent irq usage for each lock
2128 * so even though there cannot be a race this early in
2129 * the boot sequence, we still disable irqs.
2131 local_irq_save(flags);
2132 add_partial(n, page, 0);
2133 local_irq_restore(flags);
2137 static void free_kmem_cache_nodes(struct kmem_cache *s)
2141 for_each_node_state(node, N_NORMAL_MEMORY) {
2142 struct kmem_cache_node *n = s->node[node];
2143 if (n && n != &s->local_node)
2144 kmem_cache_free(kmalloc_caches, n);
2145 s->node[node] = NULL;
2149 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2154 if (slab_state >= UP)
2155 local_node = page_to_nid(virt_to_page(s));
2159 for_each_node_state(node, N_NORMAL_MEMORY) {
2160 struct kmem_cache_node *n;
2162 if (local_node == node)
2165 if (slab_state == DOWN) {
2166 n = early_kmem_cache_node_alloc(gfpflags,
2170 n = kmem_cache_alloc_node(kmalloc_caches,
2174 free_kmem_cache_nodes(s);
2180 init_kmem_cache_node(n);
2185 static void free_kmem_cache_nodes(struct kmem_cache *s)
2189 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2191 init_kmem_cache_node(&s->local_node);
2197 * calculate_sizes() determines the order and the distribution of data within
2200 static int calculate_sizes(struct kmem_cache *s)
2202 unsigned long flags = s->flags;
2203 unsigned long size = s->objsize;
2204 unsigned long align = s->align;
2207 * Round up object size to the next word boundary. We can only
2208 * place the free pointer at word boundaries and this determines
2209 * the possible location of the free pointer.
2211 size = ALIGN(size, sizeof(void *));
2213 #ifdef CONFIG_SLUB_DEBUG
2215 * Determine if we can poison the object itself. If the user of
2216 * the slab may touch the object after free or before allocation
2217 * then we should never poison the object itself.
2219 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2221 s->flags |= __OBJECT_POISON;
2223 s->flags &= ~__OBJECT_POISON;
2227 * If we are Redzoning then check if there is some space between the
2228 * end of the object and the free pointer. If not then add an
2229 * additional word to have some bytes to store Redzone information.
2231 if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2232 size += sizeof(void *);
2236 * With that we have determined the number of bytes in actual use
2237 * by the object. This is the potential offset to the free pointer.
2241 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2244 * Relocate free pointer after the object if it is not
2245 * permitted to overwrite the first word of the object on
2248 * This is the case if we do RCU, have a constructor or
2249 * destructor or are poisoning the objects.
2252 size += sizeof(void *);
2255 #ifdef CONFIG_SLUB_DEBUG
2256 if (flags & SLAB_STORE_USER)
2258 * Need to store information about allocs and frees after
2261 size += 2 * sizeof(struct track);
2263 if (flags & SLAB_RED_ZONE)
2265 * Add some empty padding so that we can catch
2266 * overwrites from earlier objects rather than let
2267 * tracking information or the free pointer be
2268 * corrupted if an user writes before the start
2271 size += sizeof(void *);
2275 * Determine the alignment based on various parameters that the
2276 * user specified and the dynamic determination of cache line size
2279 align = calculate_alignment(flags, align, s->objsize);
2282 * SLUB stores one object immediately after another beginning from
2283 * offset 0. In order to align the objects we have to simply size
2284 * each object to conform to the alignment.
2286 size = ALIGN(size, align);
2289 if ((flags & __KMALLOC_CACHE) &&
2290 PAGE_SIZE / size < slub_min_objects) {
2292 * Kmalloc cache that would not have enough objects in
2293 * an order 0 page. Kmalloc slabs can fallback to
2294 * page allocator order 0 allocs so take a reasonably large
2295 * order that will allows us a good number of objects.
2297 s->order = max(slub_max_order, PAGE_ALLOC_COSTLY_ORDER);
2298 s->flags |= __PAGE_ALLOC_FALLBACK;
2299 s->allocflags |= __GFP_NOWARN;
2301 s->order = calculate_order(size);
2308 s->allocflags |= __GFP_COMP;
2310 if (s->flags & SLAB_CACHE_DMA)
2311 s->allocflags |= SLUB_DMA;
2313 if (s->flags & SLAB_RECLAIM_ACCOUNT)
2314 s->allocflags |= __GFP_RECLAIMABLE;
2317 * Determine the number of objects per slab
2319 s->objects = (PAGE_SIZE << s->order) / size;
2321 return !!s->objects;
2325 static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
2326 const char *name, size_t size,
2327 size_t align, unsigned long flags,
2328 void (*ctor)(struct kmem_cache *, void *))
2330 memset(s, 0, kmem_size);
2335 s->flags = kmem_cache_flags(size, flags, name, ctor);
2337 if (!calculate_sizes(s))
2342 s->remote_node_defrag_ratio = 100;
2344 if (!init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
2347 if (alloc_kmem_cache_cpus(s, gfpflags & ~SLUB_DMA))
2349 free_kmem_cache_nodes(s);
2351 if (flags & SLAB_PANIC)
2352 panic("Cannot create slab %s size=%lu realsize=%u "
2353 "order=%u offset=%u flags=%lx\n",
2354 s->name, (unsigned long)size, s->size, s->order,
2360 * Check if a given pointer is valid
2362 int kmem_ptr_validate(struct kmem_cache *s, const void *object)
2366 page = get_object_page(object);
2368 if (!page || s != page->slab)
2369 /* No slab or wrong slab */
2372 if (!check_valid_pointer(s, page, object))
2376 * We could also check if the object is on the slabs freelist.
2377 * But this would be too expensive and it seems that the main
2378 * purpose of kmem_ptr_valid() is to check if the object belongs
2379 * to a certain slab.
2383 EXPORT_SYMBOL(kmem_ptr_validate);
2386 * Determine the size of a slab object
2388 unsigned int kmem_cache_size(struct kmem_cache *s)
2392 EXPORT_SYMBOL(kmem_cache_size);
2394 const char *kmem_cache_name(struct kmem_cache *s)
2398 EXPORT_SYMBOL(kmem_cache_name);
2400 static void list_slab_objects(struct kmem_cache *s, struct page *page,
2403 #ifdef CONFIG_SLUB_DEBUG
2404 void *addr = page_address(page);
2406 DECLARE_BITMAP(map, page->objects);
2408 bitmap_zero(map, page->objects);
2409 slab_err(s, page, "%s", text);
2411 for_each_free_object(p, s, page->freelist)
2412 set_bit(slab_index(p, s, addr), map);
2414 for_each_object(p, s, addr, page->objects) {
2416 if (!test_bit(slab_index(p, s, addr), map)) {
2417 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
2419 print_tracking(s, p);
2427 * Attempt to free all partial slabs on a node.
2429 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
2431 unsigned long flags;
2432 struct page *page, *h;
2434 spin_lock_irqsave(&n->list_lock, flags);
2435 list_for_each_entry_safe(page, h, &n->partial, lru) {
2437 list_del(&page->lru);
2438 discard_slab(s, page);
2441 list_slab_objects(s, page,
2442 "Objects remaining on kmem_cache_close()");
2445 spin_unlock_irqrestore(&n->list_lock, flags);
2449 * Release all resources used by a slab cache.
2451 static inline int kmem_cache_close(struct kmem_cache *s)
2457 /* Attempt to free all objects */
2458 free_kmem_cache_cpus(s);
2459 for_each_node_state(node, N_NORMAL_MEMORY) {
2460 struct kmem_cache_node *n = get_node(s, node);
2463 if (n->nr_partial || slabs_node(s, node))
2466 free_kmem_cache_nodes(s);
2471 * Close a cache and release the kmem_cache structure
2472 * (must be used for caches created using kmem_cache_create)
2474 void kmem_cache_destroy(struct kmem_cache *s)
2476 down_write(&slub_lock);
2480 up_write(&slub_lock);
2481 if (kmem_cache_close(s)) {
2482 printk(KERN_ERR "SLUB %s: %s called for cache that "
2483 "still has objects.\n", s->name, __func__);
2486 sysfs_slab_remove(s);
2488 up_write(&slub_lock);
2490 EXPORT_SYMBOL(kmem_cache_destroy);
2492 /********************************************************************
2494 *******************************************************************/
2496 struct kmem_cache kmalloc_caches[PAGE_SHIFT + 1] __cacheline_aligned;
2497 EXPORT_SYMBOL(kmalloc_caches);
2499 static int __init setup_slub_min_order(char *str)
2501 get_option(&str, &slub_min_order);
2506 __setup("slub_min_order=", setup_slub_min_order);
2508 static int __init setup_slub_max_order(char *str)
2510 get_option(&str, &slub_max_order);
2515 __setup("slub_max_order=", setup_slub_max_order);
2517 static int __init setup_slub_min_objects(char *str)
2519 get_option(&str, &slub_min_objects);
2524 __setup("slub_min_objects=", setup_slub_min_objects);
2526 static int __init setup_slub_nomerge(char *str)
2532 __setup("slub_nomerge", setup_slub_nomerge);
2534 static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
2535 const char *name, int size, gfp_t gfp_flags)
2537 unsigned int flags = 0;
2539 if (gfp_flags & SLUB_DMA)
2540 flags = SLAB_CACHE_DMA;
2542 down_write(&slub_lock);
2543 if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
2544 flags | __KMALLOC_CACHE, NULL))
2547 list_add(&s->list, &slab_caches);
2548 up_write(&slub_lock);
2549 if (sysfs_slab_add(s))
2554 panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
2557 #ifdef CONFIG_ZONE_DMA
2558 static struct kmem_cache *kmalloc_caches_dma[PAGE_SHIFT + 1];
2560 static void sysfs_add_func(struct work_struct *w)
2562 struct kmem_cache *s;
2564 down_write(&slub_lock);
2565 list_for_each_entry(s, &slab_caches, list) {
2566 if (s->flags & __SYSFS_ADD_DEFERRED) {
2567 s->flags &= ~__SYSFS_ADD_DEFERRED;
2571 up_write(&slub_lock);
2574 static DECLARE_WORK(sysfs_add_work, sysfs_add_func);
2576 static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
2578 struct kmem_cache *s;
2582 s = kmalloc_caches_dma[index];
2586 /* Dynamically create dma cache */
2587 if (flags & __GFP_WAIT)
2588 down_write(&slub_lock);
2590 if (!down_write_trylock(&slub_lock))
2594 if (kmalloc_caches_dma[index])
2597 realsize = kmalloc_caches[index].objsize;
2598 text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
2599 (unsigned int)realsize);
2600 s = kmalloc(kmem_size, flags & ~SLUB_DMA);
2602 if (!s || !text || !kmem_cache_open(s, flags, text,
2603 realsize, ARCH_KMALLOC_MINALIGN,
2604 SLAB_CACHE_DMA|__SYSFS_ADD_DEFERRED, NULL)) {
2610 list_add(&s->list, &slab_caches);
2611 kmalloc_caches_dma[index] = s;
2613 schedule_work(&sysfs_add_work);
2616 up_write(&slub_lock);
2618 return kmalloc_caches_dma[index];
2623 * Conversion table for small slabs sizes / 8 to the index in the
2624 * kmalloc array. This is necessary for slabs < 192 since we have non power
2625 * of two cache sizes there. The size of larger slabs can be determined using
2628 static s8 size_index[24] = {
2655 static struct kmem_cache *get_slab(size_t size, gfp_t flags)
2661 return ZERO_SIZE_PTR;
2663 index = size_index[(size - 1) / 8];
2665 index = fls(size - 1);
2667 #ifdef CONFIG_ZONE_DMA
2668 if (unlikely((flags & SLUB_DMA)))
2669 return dma_kmalloc_cache(index, flags);
2672 return &kmalloc_caches[index];
2675 void *__kmalloc(size_t size, gfp_t flags)
2677 struct kmem_cache *s;
2679 if (unlikely(size > PAGE_SIZE))
2680 return kmalloc_large(size, flags);
2682 s = get_slab(size, flags);
2684 if (unlikely(ZERO_OR_NULL_PTR(s)))
2687 return slab_alloc(s, flags, -1, __builtin_return_address(0));
2689 EXPORT_SYMBOL(__kmalloc);
2691 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
2693 struct page *page = alloc_pages_node(node, flags | __GFP_COMP,
2697 return page_address(page);
2703 void *__kmalloc_node(size_t size, gfp_t flags, int node)
2705 struct kmem_cache *s;
2707 if (unlikely(size > PAGE_SIZE))
2708 return kmalloc_large_node(size, flags, node);
2710 s = get_slab(size, flags);
2712 if (unlikely(ZERO_OR_NULL_PTR(s)))
2715 return slab_alloc(s, flags, node, __builtin_return_address(0));
2717 EXPORT_SYMBOL(__kmalloc_node);
2720 size_t ksize(const void *object)
2723 struct kmem_cache *s;
2725 if (unlikely(object == ZERO_SIZE_PTR))
2728 page = virt_to_head_page(object);
2730 if (unlikely(!PageSlab(page)))
2731 return PAGE_SIZE << compound_order(page);
2735 #ifdef CONFIG_SLUB_DEBUG
2737 * Debugging requires use of the padding between object
2738 * and whatever may come after it.
2740 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
2745 * If we have the need to store the freelist pointer
2746 * back there or track user information then we can
2747 * only use the space before that information.
2749 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
2752 * Else we can use all the padding etc for the allocation
2756 EXPORT_SYMBOL(ksize);
2758 void kfree(const void *x)
2761 void *object = (void *)x;
2763 if (unlikely(ZERO_OR_NULL_PTR(x)))
2766 page = virt_to_head_page(x);
2767 if (unlikely(!PageSlab(page))) {
2771 slab_free(page->slab, page, object, __builtin_return_address(0));
2773 EXPORT_SYMBOL(kfree);
2776 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2777 * the remaining slabs by the number of items in use. The slabs with the
2778 * most items in use come first. New allocations will then fill those up
2779 * and thus they can be removed from the partial lists.
2781 * The slabs with the least items are placed last. This results in them
2782 * being allocated from last increasing the chance that the last objects
2783 * are freed in them.
2785 int kmem_cache_shrink(struct kmem_cache *s)
2789 struct kmem_cache_node *n;
2792 struct list_head *slabs_by_inuse =
2793 kmalloc(sizeof(struct list_head) * s->objects, GFP_KERNEL);
2794 unsigned long flags;
2796 if (!slabs_by_inuse)
2800 for_each_node_state(node, N_NORMAL_MEMORY) {
2801 n = get_node(s, node);
2806 for (i = 0; i < s->objects; i++)
2807 INIT_LIST_HEAD(slabs_by_inuse + i);
2809 spin_lock_irqsave(&n->list_lock, flags);
2812 * Build lists indexed by the items in use in each slab.
2814 * Note that concurrent frees may occur while we hold the
2815 * list_lock. page->inuse here is the upper limit.
2817 list_for_each_entry_safe(page, t, &n->partial, lru) {
2818 if (!page->inuse && slab_trylock(page)) {
2820 * Must hold slab lock here because slab_free
2821 * may have freed the last object and be
2822 * waiting to release the slab.
2824 list_del(&page->lru);
2827 discard_slab(s, page);
2829 list_move(&page->lru,
2830 slabs_by_inuse + page->inuse);
2835 * Rebuild the partial list with the slabs filled up most
2836 * first and the least used slabs at the end.
2838 for (i = s->objects - 1; i >= 0; i--)
2839 list_splice(slabs_by_inuse + i, n->partial.prev);
2841 spin_unlock_irqrestore(&n->list_lock, flags);
2844 kfree(slabs_by_inuse);
2847 EXPORT_SYMBOL(kmem_cache_shrink);
2849 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
2850 static int slab_mem_going_offline_callback(void *arg)
2852 struct kmem_cache *s;
2854 down_read(&slub_lock);
2855 list_for_each_entry(s, &slab_caches, list)
2856 kmem_cache_shrink(s);
2857 up_read(&slub_lock);
2862 static void slab_mem_offline_callback(void *arg)
2864 struct kmem_cache_node *n;
2865 struct kmem_cache *s;
2866 struct memory_notify *marg = arg;
2869 offline_node = marg->status_change_nid;
2872 * If the node still has available memory. we need kmem_cache_node
2875 if (offline_node < 0)
2878 down_read(&slub_lock);
2879 list_for_each_entry(s, &slab_caches, list) {
2880 n = get_node(s, offline_node);
2883 * if n->nr_slabs > 0, slabs still exist on the node
2884 * that is going down. We were unable to free them,
2885 * and offline_pages() function shoudn't call this
2886 * callback. So, we must fail.
2888 BUG_ON(slabs_node(s, offline_node));
2890 s->node[offline_node] = NULL;
2891 kmem_cache_free(kmalloc_caches, n);
2894 up_read(&slub_lock);
2897 static int slab_mem_going_online_callback(void *arg)
2899 struct kmem_cache_node *n;
2900 struct kmem_cache *s;
2901 struct memory_notify *marg = arg;
2902 int nid = marg->status_change_nid;
2906 * If the node's memory is already available, then kmem_cache_node is
2907 * already created. Nothing to do.
2913 * We are bringing a node online. No memory is availabe yet. We must
2914 * allocate a kmem_cache_node structure in order to bring the node
2917 down_read(&slub_lock);
2918 list_for_each_entry(s, &slab_caches, list) {
2920 * XXX: kmem_cache_alloc_node will fallback to other nodes
2921 * since memory is not yet available from the node that
2924 n = kmem_cache_alloc(kmalloc_caches, GFP_KERNEL);
2929 init_kmem_cache_node(n);
2933 up_read(&slub_lock);
2937 static int slab_memory_callback(struct notifier_block *self,
2938 unsigned long action, void *arg)
2943 case MEM_GOING_ONLINE:
2944 ret = slab_mem_going_online_callback(arg);
2946 case MEM_GOING_OFFLINE:
2947 ret = slab_mem_going_offline_callback(arg);
2950 case MEM_CANCEL_ONLINE:
2951 slab_mem_offline_callback(arg);
2954 case MEM_CANCEL_OFFLINE:
2958 ret = notifier_from_errno(ret);
2962 #endif /* CONFIG_MEMORY_HOTPLUG */
2964 /********************************************************************
2965 * Basic setup of slabs
2966 *******************************************************************/
2968 void __init kmem_cache_init(void)
2977 * Must first have the slab cache available for the allocations of the
2978 * struct kmem_cache_node's. There is special bootstrap code in
2979 * kmem_cache_open for slab_state == DOWN.
2981 create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node",
2982 sizeof(struct kmem_cache_node), GFP_KERNEL);
2983 kmalloc_caches[0].refcount = -1;
2986 hotplug_memory_notifier(slab_memory_callback, 1);
2989 /* Able to allocate the per node structures */
2990 slab_state = PARTIAL;
2992 /* Caches that are not of the two-to-the-power-of size */
2993 if (KMALLOC_MIN_SIZE <= 64) {
2994 create_kmalloc_cache(&kmalloc_caches[1],
2995 "kmalloc-96", 96, GFP_KERNEL);
2998 if (KMALLOC_MIN_SIZE <= 128) {
2999 create_kmalloc_cache(&kmalloc_caches[2],
3000 "kmalloc-192", 192, GFP_KERNEL);
3004 for (i = KMALLOC_SHIFT_LOW; i <= PAGE_SHIFT; i++) {
3005 create_kmalloc_cache(&kmalloc_caches[i],
3006 "kmalloc", 1 << i, GFP_KERNEL);
3012 * Patch up the size_index table if we have strange large alignment
3013 * requirements for the kmalloc array. This is only the case for
3014 * MIPS it seems. The standard arches will not generate any code here.
3016 * Largest permitted alignment is 256 bytes due to the way we
3017 * handle the index determination for the smaller caches.
3019 * Make sure that nothing crazy happens if someone starts tinkering
3020 * around with ARCH_KMALLOC_MINALIGN
3022 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3023 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3025 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8)
3026 size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW;
3030 /* Provide the correct kmalloc names now that the caches are up */
3031 for (i = KMALLOC_SHIFT_LOW; i <= PAGE_SHIFT; i++)
3032 kmalloc_caches[i]. name =
3033 kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i);
3036 register_cpu_notifier(&slab_notifier);
3037 kmem_size = offsetof(struct kmem_cache, cpu_slab) +
3038 nr_cpu_ids * sizeof(struct kmem_cache_cpu *);
3040 kmem_size = sizeof(struct kmem_cache);
3044 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3045 " CPUs=%d, Nodes=%d\n",
3046 caches, cache_line_size(),
3047 slub_min_order, slub_max_order, slub_min_objects,
3048 nr_cpu_ids, nr_node_ids);
3052 * Find a mergeable slab cache
3054 static int slab_unmergeable(struct kmem_cache *s)
3056 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3059 if ((s->flags & __PAGE_ALLOC_FALLBACK))
3066 * We may have set a slab to be unmergeable during bootstrap.
3068 if (s->refcount < 0)
3074 static struct kmem_cache *find_mergeable(size_t size,
3075 size_t align, unsigned long flags, const char *name,
3076 void (*ctor)(struct kmem_cache *, void *))
3078 struct kmem_cache *s;
3080 if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3086 size = ALIGN(size, sizeof(void *));
3087 align = calculate_alignment(flags, align, size);
3088 size = ALIGN(size, align);
3089 flags = kmem_cache_flags(size, flags, name, NULL);
3091 list_for_each_entry(s, &slab_caches, list) {
3092 if (slab_unmergeable(s))
3098 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3101 * Check if alignment is compatible.
3102 * Courtesy of Adrian Drzewiecki
3104 if ((s->size & ~(align - 1)) != s->size)
3107 if (s->size - size >= sizeof(void *))
3115 struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3116 size_t align, unsigned long flags,
3117 void (*ctor)(struct kmem_cache *, void *))
3119 struct kmem_cache *s;
3121 down_write(&slub_lock);
3122 s = find_mergeable(size, align, flags, name, ctor);
3128 * Adjust the object sizes so that we clear
3129 * the complete object on kzalloc.
3131 s->objsize = max(s->objsize, (int)size);
3134 * And then we need to update the object size in the
3135 * per cpu structures
3137 for_each_online_cpu(cpu)
3138 get_cpu_slab(s, cpu)->objsize = s->objsize;
3140 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3141 up_write(&slub_lock);
3143 if (sysfs_slab_alias(s, name))
3148 s = kmalloc(kmem_size, GFP_KERNEL);
3150 if (kmem_cache_open(s, GFP_KERNEL, name,
3151 size, align, flags, ctor)) {
3152 list_add(&s->list, &slab_caches);
3153 up_write(&slub_lock);
3154 if (sysfs_slab_add(s))
3160 up_write(&slub_lock);
3163 if (flags & SLAB_PANIC)
3164 panic("Cannot create slabcache %s\n", name);
3169 EXPORT_SYMBOL(kmem_cache_create);
3173 * Use the cpu notifier to insure that the cpu slabs are flushed when
3176 static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3177 unsigned long action, void *hcpu)
3179 long cpu = (long)hcpu;
3180 struct kmem_cache *s;
3181 unsigned long flags;
3184 case CPU_UP_PREPARE:
3185 case CPU_UP_PREPARE_FROZEN:
3186 init_alloc_cpu_cpu(cpu);
3187 down_read(&slub_lock);
3188 list_for_each_entry(s, &slab_caches, list)
3189 s->cpu_slab[cpu] = alloc_kmem_cache_cpu(s, cpu,
3191 up_read(&slub_lock);
3194 case CPU_UP_CANCELED:
3195 case CPU_UP_CANCELED_FROZEN:
3197 case CPU_DEAD_FROZEN:
3198 down_read(&slub_lock);
3199 list_for_each_entry(s, &slab_caches, list) {
3200 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3202 local_irq_save(flags);
3203 __flush_cpu_slab(s, cpu);
3204 local_irq_restore(flags);
3205 free_kmem_cache_cpu(c, cpu);
3206 s->cpu_slab[cpu] = NULL;
3208 up_read(&slub_lock);
3216 static struct notifier_block __cpuinitdata slab_notifier = {
3217 .notifier_call = slab_cpuup_callback
3222 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller)
3224 struct kmem_cache *s;
3226 if (unlikely(size > PAGE_SIZE))
3227 return kmalloc_large(size, gfpflags);
3229 s = get_slab(size, gfpflags);
3231 if (unlikely(ZERO_OR_NULL_PTR(s)))
3234 return slab_alloc(s, gfpflags, -1, caller);
3237 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3238 int node, void *caller)
3240 struct kmem_cache *s;
3242 if (unlikely(size > PAGE_SIZE))
3243 return kmalloc_large_node(size, gfpflags, node);
3245 s = get_slab(size, gfpflags);
3247 if (unlikely(ZERO_OR_NULL_PTR(s)))
3250 return slab_alloc(s, gfpflags, node, caller);
3253 #if (defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)) || defined(CONFIG_SLABINFO)
3254 static unsigned long count_partial(struct kmem_cache_node *n)
3256 unsigned long flags;
3257 unsigned long x = 0;
3260 spin_lock_irqsave(&n->list_lock, flags);
3261 list_for_each_entry(page, &n->partial, lru)
3263 spin_unlock_irqrestore(&n->list_lock, flags);
3268 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
3269 static int validate_slab(struct kmem_cache *s, struct page *page,
3273 void *addr = page_address(page);
3275 if (!check_slab(s, page) ||
3276 !on_freelist(s, page, NULL))
3279 /* Now we know that a valid freelist exists */
3280 bitmap_zero(map, page->objects);
3282 for_each_free_object(p, s, page->freelist) {
3283 set_bit(slab_index(p, s, addr), map);
3284 if (!check_object(s, page, p, 0))
3288 for_each_object(p, s, addr, page->objects)
3289 if (!test_bit(slab_index(p, s, addr), map))
3290 if (!check_object(s, page, p, 1))
3295 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3298 if (slab_trylock(page)) {
3299 validate_slab(s, page, map);
3302 printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
3305 if (s->flags & DEBUG_DEFAULT_FLAGS) {
3306 if (!SlabDebug(page))
3307 printk(KERN_ERR "SLUB %s: SlabDebug not set "
3308 "on slab 0x%p\n", s->name, page);
3310 if (SlabDebug(page))
3311 printk(KERN_ERR "SLUB %s: SlabDebug set on "
3312 "slab 0x%p\n", s->name, page);
3316 static int validate_slab_node(struct kmem_cache *s,
3317 struct kmem_cache_node *n, unsigned long *map)
3319 unsigned long count = 0;
3321 unsigned long flags;
3323 spin_lock_irqsave(&n->list_lock, flags);
3325 list_for_each_entry(page, &n->partial, lru) {
3326 validate_slab_slab(s, page, map);
3329 if (count != n->nr_partial)
3330 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3331 "counter=%ld\n", s->name, count, n->nr_partial);
3333 if (!(s->flags & SLAB_STORE_USER))
3336 list_for_each_entry(page, &n->full, lru) {
3337 validate_slab_slab(s, page, map);
3340 if (count != atomic_long_read(&n->nr_slabs))
3341 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3342 "counter=%ld\n", s->name, count,
3343 atomic_long_read(&n->nr_slabs));
3346 spin_unlock_irqrestore(&n->list_lock, flags);
3350 static long validate_slab_cache(struct kmem_cache *s)
3353 unsigned long count = 0;
3354 unsigned long *map = kmalloc(BITS_TO_LONGS(s->objects) *
3355 sizeof(unsigned long), GFP_KERNEL);
3361 for_each_node_state(node, N_NORMAL_MEMORY) {
3362 struct kmem_cache_node *n = get_node(s, node);
3364 count += validate_slab_node(s, n, map);
3370 #ifdef SLUB_RESILIENCY_TEST
3371 static void resiliency_test(void)
3375 printk(KERN_ERR "SLUB resiliency testing\n");
3376 printk(KERN_ERR "-----------------------\n");
3377 printk(KERN_ERR "A. Corruption after allocation\n");
3379 p = kzalloc(16, GFP_KERNEL);
3381 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
3382 " 0x12->0x%p\n\n", p + 16);
3384 validate_slab_cache(kmalloc_caches + 4);
3386 /* Hmmm... The next two are dangerous */
3387 p = kzalloc(32, GFP_KERNEL);
3388 p[32 + sizeof(void *)] = 0x34;
3389 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
3390 " 0x34 -> -0x%p\n", p);
3392 "If allocated object is overwritten then not detectable\n\n");
3394 validate_slab_cache(kmalloc_caches + 5);
3395 p = kzalloc(64, GFP_KERNEL);
3396 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
3398 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
3401 "If allocated object is overwritten then not detectable\n\n");
3402 validate_slab_cache(kmalloc_caches + 6);
3404 printk(KERN_ERR "\nB. Corruption after free\n");
3405 p = kzalloc(128, GFP_KERNEL);
3408 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
3409 validate_slab_cache(kmalloc_caches + 7);
3411 p = kzalloc(256, GFP_KERNEL);
3414 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
3416 validate_slab_cache(kmalloc_caches + 8);
3418 p = kzalloc(512, GFP_KERNEL);
3421 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
3422 validate_slab_cache(kmalloc_caches + 9);
3425 static void resiliency_test(void) {};
3429 * Generate lists of code addresses where slabcache objects are allocated
3434 unsigned long count;
3447 unsigned long count;
3448 struct location *loc;
3451 static void free_loc_track(struct loc_track *t)
3454 free_pages((unsigned long)t->loc,
3455 get_order(sizeof(struct location) * t->max));
3458 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
3463 order = get_order(sizeof(struct location) * max);
3465 l = (void *)__get_free_pages(flags, order);
3470 memcpy(l, t->loc, sizeof(struct location) * t->count);
3478 static int add_location(struct loc_track *t, struct kmem_cache *s,
3479 const struct track *track)
3481 long start, end, pos;
3484 unsigned long age = jiffies - track->when;
3490 pos = start + (end - start + 1) / 2;
3493 * There is nothing at "end". If we end up there
3494 * we need to add something to before end.
3499 caddr = t->loc[pos].addr;
3500 if (track->addr == caddr) {
3506 if (age < l->min_time)
3508 if (age > l->max_time)
3511 if (track->pid < l->min_pid)
3512 l->min_pid = track->pid;
3513 if (track->pid > l->max_pid)
3514 l->max_pid = track->pid;
3516 cpu_set(track->cpu, l->cpus);
3518 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3522 if (track->addr < caddr)
3529 * Not found. Insert new tracking element.
3531 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
3537 (t->count - pos) * sizeof(struct location));
3540 l->addr = track->addr;
3544 l->min_pid = track->pid;
3545 l->max_pid = track->pid;
3546 cpus_clear(l->cpus);
3547 cpu_set(track->cpu, l->cpus);
3548 nodes_clear(l->nodes);
3549 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3553 static void process_slab(struct loc_track *t, struct kmem_cache *s,
3554 struct page *page, enum track_item alloc)
3556 void *addr = page_address(page);
3557 DECLARE_BITMAP(map, page->objects);
3560 bitmap_zero(map, page->objects);
3561 for_each_free_object(p, s, page->freelist)
3562 set_bit(slab_index(p, s, addr), map);
3564 for_each_object(p, s, addr, page->objects)
3565 if (!test_bit(slab_index(p, s, addr), map))
3566 add_location(t, s, get_track(s, p, alloc));
3569 static int list_locations(struct kmem_cache *s, char *buf,
3570 enum track_item alloc)
3574 struct loc_track t = { 0, 0, NULL };
3577 if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
3579 return sprintf(buf, "Out of memory\n");
3581 /* Push back cpu slabs */
3584 for_each_node_state(node, N_NORMAL_MEMORY) {
3585 struct kmem_cache_node *n = get_node(s, node);
3586 unsigned long flags;
3589 if (!atomic_long_read(&n->nr_slabs))
3592 spin_lock_irqsave(&n->list_lock, flags);
3593 list_for_each_entry(page, &n->partial, lru)
3594 process_slab(&t, s, page, alloc);
3595 list_for_each_entry(page, &n->full, lru)
3596 process_slab(&t, s, page, alloc);
3597 spin_unlock_irqrestore(&n->list_lock, flags);
3600 for (i = 0; i < t.count; i++) {
3601 struct location *l = &t.loc[i];
3603 if (len > PAGE_SIZE - 100)
3605 len += sprintf(buf + len, "%7ld ", l->count);
3608 len += sprint_symbol(buf + len, (unsigned long)l->addr);
3610 len += sprintf(buf + len, "<not-available>");
3612 if (l->sum_time != l->min_time) {
3613 unsigned long remainder;
3615 len += sprintf(buf + len, " age=%ld/%ld/%ld",
3617 div_long_long_rem(l->sum_time, l->count, &remainder),
3620 len += sprintf(buf + len, " age=%ld",
3623 if (l->min_pid != l->max_pid)
3624 len += sprintf(buf + len, " pid=%ld-%ld",
3625 l->min_pid, l->max_pid);
3627 len += sprintf(buf + len, " pid=%ld",
3630 if (num_online_cpus() > 1 && !cpus_empty(l->cpus) &&
3631 len < PAGE_SIZE - 60) {
3632 len += sprintf(buf + len, " cpus=");
3633 len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3637 if (num_online_nodes() > 1 && !nodes_empty(l->nodes) &&
3638 len < PAGE_SIZE - 60) {
3639 len += sprintf(buf + len, " nodes=");
3640 len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3644 len += sprintf(buf + len, "\n");
3649 len += sprintf(buf, "No data\n");
3653 enum slab_stat_type {
3660 #define SO_FULL (1 << SL_FULL)
3661 #define SO_PARTIAL (1 << SL_PARTIAL)
3662 #define SO_CPU (1 << SL_CPU)
3663 #define SO_OBJECTS (1 << SL_OBJECTS)
3665 static ssize_t show_slab_objects(struct kmem_cache *s,
3666 char *buf, unsigned long flags)
3668 unsigned long total = 0;
3672 unsigned long *nodes;
3673 unsigned long *per_cpu;
3675 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
3678 per_cpu = nodes + nr_node_ids;
3680 for_each_possible_cpu(cpu) {
3682 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3692 if (flags & SO_CPU) {
3693 if (flags & SO_OBJECTS)
3704 for_each_node_state(node, N_NORMAL_MEMORY) {
3705 struct kmem_cache_node *n = get_node(s, node);
3707 if (flags & SO_PARTIAL) {
3708 if (flags & SO_OBJECTS)
3709 x = count_partial(n);
3716 if (flags & SO_FULL) {
3717 int full_slabs = atomic_long_read(&n->nr_slabs)
3721 if (flags & SO_OBJECTS)
3722 x = full_slabs * s->objects;
3730 x = sprintf(buf, "%lu", total);
3732 for_each_node_state(node, N_NORMAL_MEMORY)
3734 x += sprintf(buf + x, " N%d=%lu",
3738 return x + sprintf(buf + x, "\n");
3741 static int any_slab_objects(struct kmem_cache *s)
3746 for_each_possible_cpu(cpu) {
3747 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3753 for_each_online_node(node) {
3754 struct kmem_cache_node *n = get_node(s, node);
3759 if (n->nr_partial || atomic_long_read(&n->nr_slabs))
3765 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3766 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3768 struct slab_attribute {
3769 struct attribute attr;
3770 ssize_t (*show)(struct kmem_cache *s, char *buf);
3771 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
3774 #define SLAB_ATTR_RO(_name) \
3775 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3777 #define SLAB_ATTR(_name) \
3778 static struct slab_attribute _name##_attr = \
3779 __ATTR(_name, 0644, _name##_show, _name##_store)
3781 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
3783 return sprintf(buf, "%d\n", s->size);
3785 SLAB_ATTR_RO(slab_size);
3787 static ssize_t align_show(struct kmem_cache *s, char *buf)
3789 return sprintf(buf, "%d\n", s->align);
3791 SLAB_ATTR_RO(align);
3793 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
3795 return sprintf(buf, "%d\n", s->objsize);
3797 SLAB_ATTR_RO(object_size);
3799 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
3801 return sprintf(buf, "%d\n", s->objects);
3803 SLAB_ATTR_RO(objs_per_slab);
3805 static ssize_t order_show(struct kmem_cache *s, char *buf)
3807 return sprintf(buf, "%d\n", s->order);
3809 SLAB_ATTR_RO(order);
3811 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
3814 int n = sprint_symbol(buf, (unsigned long)s->ctor);
3816 return n + sprintf(buf + n, "\n");
3822 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
3824 return sprintf(buf, "%d\n", s->refcount - 1);
3826 SLAB_ATTR_RO(aliases);
3828 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
3830 return show_slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU);
3832 SLAB_ATTR_RO(slabs);
3834 static ssize_t partial_show(struct kmem_cache *s, char *buf)
3836 return show_slab_objects(s, buf, SO_PARTIAL);
3838 SLAB_ATTR_RO(partial);
3840 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
3842 return show_slab_objects(s, buf, SO_CPU);
3844 SLAB_ATTR_RO(cpu_slabs);
3846 static ssize_t objects_show(struct kmem_cache *s, char *buf)
3848 return show_slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU|SO_OBJECTS);
3850 SLAB_ATTR_RO(objects);
3852 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
3854 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
3857 static ssize_t sanity_checks_store(struct kmem_cache *s,
3858 const char *buf, size_t length)
3860 s->flags &= ~SLAB_DEBUG_FREE;
3862 s->flags |= SLAB_DEBUG_FREE;
3865 SLAB_ATTR(sanity_checks);
3867 static ssize_t trace_show(struct kmem_cache *s, char *buf)
3869 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
3872 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
3875 s->flags &= ~SLAB_TRACE;
3877 s->flags |= SLAB_TRACE;
3882 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
3884 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
3887 static ssize_t reclaim_account_store(struct kmem_cache *s,
3888 const char *buf, size_t length)
3890 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
3892 s->flags |= SLAB_RECLAIM_ACCOUNT;
3895 SLAB_ATTR(reclaim_account);
3897 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
3899 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
3901 SLAB_ATTR_RO(hwcache_align);
3903 #ifdef CONFIG_ZONE_DMA
3904 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
3906 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
3908 SLAB_ATTR_RO(cache_dma);
3911 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
3913 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
3915 SLAB_ATTR_RO(destroy_by_rcu);
3917 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
3919 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
3922 static ssize_t red_zone_store(struct kmem_cache *s,
3923 const char *buf, size_t length)
3925 if (any_slab_objects(s))
3928 s->flags &= ~SLAB_RED_ZONE;
3930 s->flags |= SLAB_RED_ZONE;
3934 SLAB_ATTR(red_zone);
3936 static ssize_t poison_show(struct kmem_cache *s, char *buf)
3938 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
3941 static ssize_t poison_store(struct kmem_cache *s,
3942 const char *buf, size_t length)
3944 if (any_slab_objects(s))
3947 s->flags &= ~SLAB_POISON;
3949 s->flags |= SLAB_POISON;
3955 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
3957 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
3960 static ssize_t store_user_store(struct kmem_cache *s,
3961 const char *buf, size_t length)
3963 if (any_slab_objects(s))
3966 s->flags &= ~SLAB_STORE_USER;
3968 s->flags |= SLAB_STORE_USER;
3972 SLAB_ATTR(store_user);
3974 static ssize_t validate_show(struct kmem_cache *s, char *buf)
3979 static ssize_t validate_store(struct kmem_cache *s,
3980 const char *buf, size_t length)
3984 if (buf[0] == '1') {
3985 ret = validate_slab_cache(s);
3991 SLAB_ATTR(validate);
3993 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
3998 static ssize_t shrink_store(struct kmem_cache *s,
3999 const char *buf, size_t length)
4001 if (buf[0] == '1') {
4002 int rc = kmem_cache_shrink(s);
4012 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4014 if (!(s->flags & SLAB_STORE_USER))
4016 return list_locations(s, buf, TRACK_ALLOC);
4018 SLAB_ATTR_RO(alloc_calls);
4020 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4022 if (!(s->flags & SLAB_STORE_USER))
4024 return list_locations(s, buf, TRACK_FREE);
4026 SLAB_ATTR_RO(free_calls);
4029 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4031 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4034 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4035 const char *buf, size_t length)
4037 int n = simple_strtoul(buf, NULL, 10);
4040 s->remote_node_defrag_ratio = n * 10;
4043 SLAB_ATTR(remote_node_defrag_ratio);
4046 #ifdef CONFIG_SLUB_STATS
4047 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4049 unsigned long sum = 0;
4052 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4057 for_each_online_cpu(cpu) {
4058 unsigned x = get_cpu_slab(s, cpu)->stat[si];
4064 len = sprintf(buf, "%lu", sum);
4067 for_each_online_cpu(cpu) {
4068 if (data[cpu] && len < PAGE_SIZE - 20)
4069 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4073 return len + sprintf(buf + len, "\n");
4076 #define STAT_ATTR(si, text) \
4077 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4079 return show_stat(s, buf, si); \
4081 SLAB_ATTR_RO(text); \
4083 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4084 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4085 STAT_ATTR(FREE_FASTPATH, free_fastpath);
4086 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4087 STAT_ATTR(FREE_FROZEN, free_frozen);
4088 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4089 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4090 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4091 STAT_ATTR(ALLOC_SLAB, alloc_slab);
4092 STAT_ATTR(ALLOC_REFILL, alloc_refill);
4093 STAT_ATTR(FREE_SLAB, free_slab);
4094 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4095 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4096 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4097 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4098 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4099 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4103 static struct attribute *slab_attrs[] = {
4104 &slab_size_attr.attr,
4105 &object_size_attr.attr,
4106 &objs_per_slab_attr.attr,
4111 &cpu_slabs_attr.attr,
4115 &sanity_checks_attr.attr,
4117 &hwcache_align_attr.attr,
4118 &reclaim_account_attr.attr,
4119 &destroy_by_rcu_attr.attr,
4120 &red_zone_attr.attr,
4122 &store_user_attr.attr,
4123 &validate_attr.attr,
4125 &alloc_calls_attr.attr,
4126 &free_calls_attr.attr,
4127 #ifdef CONFIG_ZONE_DMA
4128 &cache_dma_attr.attr,
4131 &remote_node_defrag_ratio_attr.attr,
4133 #ifdef CONFIG_SLUB_STATS
4134 &alloc_fastpath_attr.attr,
4135 &alloc_slowpath_attr.attr,
4136 &free_fastpath_attr.attr,
4137 &free_slowpath_attr.attr,
4138 &free_frozen_attr.attr,
4139 &free_add_partial_attr.attr,
4140 &free_remove_partial_attr.attr,
4141 &alloc_from_partial_attr.attr,
4142 &alloc_slab_attr.attr,
4143 &alloc_refill_attr.attr,
4144 &free_slab_attr.attr,
4145 &cpuslab_flush_attr.attr,
4146 &deactivate_full_attr.attr,
4147 &deactivate_empty_attr.attr,
4148 &deactivate_to_head_attr.attr,
4149 &deactivate_to_tail_attr.attr,
4150 &deactivate_remote_frees_attr.attr,
4155 static struct attribute_group slab_attr_group = {
4156 .attrs = slab_attrs,
4159 static ssize_t slab_attr_show(struct kobject *kobj,
4160 struct attribute *attr,
4163 struct slab_attribute *attribute;
4164 struct kmem_cache *s;
4167 attribute = to_slab_attr(attr);
4170 if (!attribute->show)
4173 err = attribute->show(s, buf);
4178 static ssize_t slab_attr_store(struct kobject *kobj,
4179 struct attribute *attr,
4180 const char *buf, size_t len)
4182 struct slab_attribute *attribute;
4183 struct kmem_cache *s;
4186 attribute = to_slab_attr(attr);
4189 if (!attribute->store)
4192 err = attribute->store(s, buf, len);
4197 static void kmem_cache_release(struct kobject *kobj)
4199 struct kmem_cache *s = to_slab(kobj);
4204 static struct sysfs_ops slab_sysfs_ops = {
4205 .show = slab_attr_show,
4206 .store = slab_attr_store,
4209 static struct kobj_type slab_ktype = {
4210 .sysfs_ops = &slab_sysfs_ops,
4211 .release = kmem_cache_release
4214 static int uevent_filter(struct kset *kset, struct kobject *kobj)
4216 struct kobj_type *ktype = get_ktype(kobj);
4218 if (ktype == &slab_ktype)
4223 static struct kset_uevent_ops slab_uevent_ops = {
4224 .filter = uevent_filter,
4227 static struct kset *slab_kset;
4229 #define ID_STR_LENGTH 64
4231 /* Create a unique string id for a slab cache:
4233 * Format :[flags-]size
4235 static char *create_unique_id(struct kmem_cache *s)
4237 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
4244 * First flags affecting slabcache operations. We will only
4245 * get here for aliasable slabs so we do not need to support
4246 * too many flags. The flags here must cover all flags that
4247 * are matched during merging to guarantee that the id is
4250 if (s->flags & SLAB_CACHE_DMA)
4252 if (s->flags & SLAB_RECLAIM_ACCOUNT)
4254 if (s->flags & SLAB_DEBUG_FREE)
4258 p += sprintf(p, "%07d", s->size);
4259 BUG_ON(p > name + ID_STR_LENGTH - 1);
4263 static int sysfs_slab_add(struct kmem_cache *s)
4269 if (slab_state < SYSFS)
4270 /* Defer until later */
4273 unmergeable = slab_unmergeable(s);
4276 * Slabcache can never be merged so we can use the name proper.
4277 * This is typically the case for debug situations. In that
4278 * case we can catch duplicate names easily.
4280 sysfs_remove_link(&slab_kset->kobj, s->name);
4284 * Create a unique name for the slab as a target
4287 name = create_unique_id(s);
4290 s->kobj.kset = slab_kset;
4291 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
4293 kobject_put(&s->kobj);
4297 err = sysfs_create_group(&s->kobj, &slab_attr_group);
4300 kobject_uevent(&s->kobj, KOBJ_ADD);
4302 /* Setup first alias */
4303 sysfs_slab_alias(s, s->name);
4309 static void sysfs_slab_remove(struct kmem_cache *s)
4311 kobject_uevent(&s->kobj, KOBJ_REMOVE);
4312 kobject_del(&s->kobj);
4313 kobject_put(&s->kobj);
4317 * Need to buffer aliases during bootup until sysfs becomes
4318 * available lest we loose that information.
4320 struct saved_alias {
4321 struct kmem_cache *s;
4323 struct saved_alias *next;
4326 static struct saved_alias *alias_list;
4328 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
4330 struct saved_alias *al;
4332 if (slab_state == SYSFS) {
4334 * If we have a leftover link then remove it.
4336 sysfs_remove_link(&slab_kset->kobj, name);
4337 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
4340 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
4346 al->next = alias_list;
4351 static int __init slab_sysfs_init(void)
4353 struct kmem_cache *s;
4356 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
4358 printk(KERN_ERR "Cannot register slab subsystem.\n");
4364 list_for_each_entry(s, &slab_caches, list) {
4365 err = sysfs_slab_add(s);
4367 printk(KERN_ERR "SLUB: Unable to add boot slab %s"
4368 " to sysfs\n", s->name);
4371 while (alias_list) {
4372 struct saved_alias *al = alias_list;
4374 alias_list = alias_list->next;
4375 err = sysfs_slab_alias(al->s, al->name);
4377 printk(KERN_ERR "SLUB: Unable to add boot slab alias"
4378 " %s to sysfs\n", s->name);
4386 __initcall(slab_sysfs_init);
4390 * The /proc/slabinfo ABI
4392 #ifdef CONFIG_SLABINFO
4394 ssize_t slabinfo_write(struct file *file, const char __user * buffer,
4395 size_t count, loff_t *ppos)
4401 static void print_slabinfo_header(struct seq_file *m)
4403 seq_puts(m, "slabinfo - version: 2.1\n");
4404 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
4405 "<objperslab> <pagesperslab>");
4406 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
4407 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4411 static void *s_start(struct seq_file *m, loff_t *pos)
4415 down_read(&slub_lock);
4417 print_slabinfo_header(m);
4419 return seq_list_start(&slab_caches, *pos);
4422 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4424 return seq_list_next(p, &slab_caches, pos);
4427 static void s_stop(struct seq_file *m, void *p)
4429 up_read(&slub_lock);
4432 static int s_show(struct seq_file *m, void *p)
4434 unsigned long nr_partials = 0;
4435 unsigned long nr_slabs = 0;
4436 unsigned long nr_inuse = 0;
4437 unsigned long nr_objs;
4438 struct kmem_cache *s;
4441 s = list_entry(p, struct kmem_cache, list);
4443 for_each_online_node(node) {
4444 struct kmem_cache_node *n = get_node(s, node);
4449 nr_partials += n->nr_partial;
4450 nr_slabs += atomic_long_read(&n->nr_slabs);
4451 nr_inuse += count_partial(n);
4454 nr_objs = nr_slabs * s->objects;
4455 nr_inuse += (nr_slabs - nr_partials) * s->objects;
4457 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
4458 nr_objs, s->size, s->objects, (1 << s->order));
4459 seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
4460 seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
4466 const struct seq_operations slabinfo_op = {
4473 #endif /* CONFIG_SLABINFO */