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
12 #include <linux/swap.h> /* struct reclaim_state */
13 #include <linux/module.h>
14 #include <linux/bit_spinlock.h>
15 #include <linux/interrupt.h>
16 #include <linux/bitops.h>
17 #include <linux/slab.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <trace/kmemtrace.h>
21 #include <linux/cpu.h>
22 #include <linux/cpuset.h>
23 #include <linux/mempolicy.h>
24 #include <linux/ctype.h>
25 #include <linux/debugobjects.h>
26 #include <linux/kallsyms.h>
27 #include <linux/memory.h>
28 #include <linux/math64.h>
29 #include <linux/fault-inject.h>
36 * The slab_lock protects operations on the object of a particular
37 * slab and its metadata in the page struct. If the slab lock
38 * has been taken then no allocations nor frees can be performed
39 * on the objects in the slab nor can the slab be added or removed
40 * from the partial or full lists since this would mean modifying
41 * the page_struct of the slab.
43 * The list_lock protects the partial and full list on each node and
44 * the partial slab counter. If taken then no new slabs may be added or
45 * removed from the lists nor make the number of partial slabs be modified.
46 * (Note that the total number of slabs is an atomic value that may be
47 * modified without taking the list lock).
49 * The list_lock is a centralized lock and thus we avoid taking it as
50 * much as possible. As long as SLUB does not have to handle partial
51 * slabs, operations can continue without any centralized lock. F.e.
52 * allocating a long series of objects that fill up slabs does not require
55 * The lock order is sometimes inverted when we are trying to get a slab
56 * off a list. We take the list_lock and then look for a page on the list
57 * to use. While we do that objects in the slabs may be freed. We can
58 * only operate on the slab if we have also taken the slab_lock. So we use
59 * a slab_trylock() on the slab. If trylock was successful then no frees
60 * can occur anymore and we can use the slab for allocations etc. If the
61 * slab_trylock() does not succeed then frees are in progress in the slab and
62 * we must stay away from it for a while since we may cause a bouncing
63 * cacheline if we try to acquire the lock. So go onto the next slab.
64 * If all pages are busy then we may allocate a new slab instead of reusing
65 * a partial slab. A new slab has noone operating on it and thus there is
66 * no danger of cacheline contention.
68 * Interrupts are disabled during allocation and deallocation in order to
69 * make the slab allocator safe to use in the context of an irq. In addition
70 * interrupts are disabled to ensure that the processor does not change
71 * while handling per_cpu slabs, due to kernel preemption.
73 * SLUB assigns one slab for allocation to each processor.
74 * Allocations only occur from these slabs called cpu slabs.
76 * Slabs with free elements are kept on a partial list and during regular
77 * operations no list for full slabs is used. If an object in a full slab is
78 * freed then the slab will show up again on the partial lists.
79 * We track full slabs for debugging purposes though because otherwise we
80 * cannot scan all objects.
82 * Slabs are freed when they become empty. Teardown and setup is
83 * minimal so we rely on the page allocators per cpu caches for
84 * fast frees and allocs.
86 * Overloading of page flags that are otherwise used for LRU management.
88 * PageActive The slab is frozen and exempt from list processing.
89 * This means that the slab is dedicated to a purpose
90 * such as satisfying allocations for a specific
91 * processor. Objects may be freed in the slab while
92 * it is frozen but slab_free will then skip the usual
93 * list operations. It is up to the processor holding
94 * the slab to integrate the slab into the slab lists
95 * when the slab is no longer needed.
97 * One use of this flag is to mark slabs that are
98 * used for allocations. Then such a slab becomes a cpu
99 * slab. The cpu slab may be equipped with an additional
100 * freelist that allows lockless access to
101 * free objects in addition to the regular freelist
102 * that requires the slab lock.
104 * PageError Slab requires special handling due to debug
105 * options set. This moves slab handling out of
106 * the fast path and disables lockless freelists.
109 #ifdef CONFIG_SLUB_DEBUG
116 * Issues still to be resolved:
118 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
120 * - Variable sizing of the per node arrays
123 /* Enable to test recovery from slab corruption on boot */
124 #undef SLUB_RESILIENCY_TEST
127 * Mininum number of partial slabs. These will be left on the partial
128 * lists even if they are empty. kmem_cache_shrink may reclaim them.
130 #define MIN_PARTIAL 5
133 * Maximum number of desirable partial slabs.
134 * The existence of more partial slabs makes kmem_cache_shrink
135 * sort the partial list by the number of objects in the.
137 #define MAX_PARTIAL 10
139 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
140 SLAB_POISON | SLAB_STORE_USER)
143 * Set of flags that will prevent slab merging
145 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
146 SLAB_TRACE | SLAB_DESTROY_BY_RCU)
148 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
151 #ifndef ARCH_KMALLOC_MINALIGN
152 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
155 #ifndef ARCH_SLAB_MINALIGN
156 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
160 #define OO_MASK ((1 << OO_SHIFT) - 1)
161 #define MAX_OBJS_PER_PAGE 65535 /* since page.objects is u16 */
163 /* Internal SLUB flags */
164 #define __OBJECT_POISON 0x80000000 /* Poison object */
165 #define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */
167 static int kmem_size = sizeof(struct kmem_cache);
170 static struct notifier_block slab_notifier;
174 DOWN, /* No slab functionality available */
175 PARTIAL, /* kmem_cache_open() works but kmalloc does not */
176 UP, /* Everything works but does not show up in sysfs */
180 /* A list of all slab caches on the system */
181 static DECLARE_RWSEM(slub_lock);
182 static LIST_HEAD(slab_caches);
185 * Tracking user of a slab.
188 unsigned long addr; /* Called from address */
189 int cpu; /* Was running on cpu */
190 int pid; /* Pid context */
191 unsigned long when; /* When did the operation occur */
194 enum track_item { TRACK_ALLOC, TRACK_FREE };
196 #ifdef CONFIG_SLUB_DEBUG
197 static int sysfs_slab_add(struct kmem_cache *);
198 static int sysfs_slab_alias(struct kmem_cache *, const char *);
199 static void sysfs_slab_remove(struct kmem_cache *);
202 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
203 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
205 static inline void sysfs_slab_remove(struct kmem_cache *s)
212 static inline void stat(struct kmem_cache_cpu *c, enum stat_item si)
214 #ifdef CONFIG_SLUB_STATS
219 /********************************************************************
220 * Core slab cache functions
221 *******************************************************************/
223 int slab_is_available(void)
225 return slab_state >= UP;
228 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
231 return s->node[node];
233 return &s->local_node;
237 static inline struct kmem_cache_cpu *get_cpu_slab(struct kmem_cache *s, int cpu)
240 return s->cpu_slab[cpu];
246 /* Verify that a pointer has an address that is valid within a slab page */
247 static inline int check_valid_pointer(struct kmem_cache *s,
248 struct page *page, const void *object)
255 base = page_address(page);
256 if (object < base || object >= base + page->objects * s->size ||
257 (object - base) % s->size) {
265 * Slow version of get and set free pointer.
267 * This version requires touching the cache lines of kmem_cache which
268 * we avoid to do in the fast alloc free paths. There we obtain the offset
269 * from the page struct.
271 static inline void *get_freepointer(struct kmem_cache *s, void *object)
273 return *(void **)(object + s->offset);
276 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
278 *(void **)(object + s->offset) = fp;
281 /* Loop over all objects in a slab */
282 #define for_each_object(__p, __s, __addr, __objects) \
283 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
287 #define for_each_free_object(__p, __s, __free) \
288 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
290 /* Determine object index from a given position */
291 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
293 return (p - addr) / s->size;
296 static inline struct kmem_cache_order_objects oo_make(int order,
299 struct kmem_cache_order_objects x = {
300 (order << OO_SHIFT) + (PAGE_SIZE << order) / size
306 static inline int oo_order(struct kmem_cache_order_objects x)
308 return x.x >> OO_SHIFT;
311 static inline int oo_objects(struct kmem_cache_order_objects x)
313 return x.x & OO_MASK;
316 #ifdef CONFIG_SLUB_DEBUG
320 #ifdef CONFIG_SLUB_DEBUG_ON
321 static int slub_debug = DEBUG_DEFAULT_FLAGS;
323 static int slub_debug;
326 static char *slub_debug_slabs;
331 static void print_section(char *text, u8 *addr, unsigned int length)
339 for (i = 0; i < length; i++) {
341 printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
344 printk(KERN_CONT " %02x", addr[i]);
346 ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
348 printk(KERN_CONT " %s\n", ascii);
355 printk(KERN_CONT " ");
359 printk(KERN_CONT " %s\n", ascii);
363 static struct track *get_track(struct kmem_cache *s, void *object,
364 enum track_item alloc)
369 p = object + s->offset + sizeof(void *);
371 p = object + s->inuse;
376 static void set_track(struct kmem_cache *s, void *object,
377 enum track_item alloc, unsigned long addr)
379 struct track *p = get_track(s, object, alloc);
383 p->cpu = smp_processor_id();
384 p->pid = current->pid;
387 memset(p, 0, sizeof(struct track));
390 static void init_tracking(struct kmem_cache *s, void *object)
392 if (!(s->flags & SLAB_STORE_USER))
395 set_track(s, object, TRACK_FREE, 0UL);
396 set_track(s, object, TRACK_ALLOC, 0UL);
399 static void print_track(const char *s, struct track *t)
404 printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
405 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
408 static void print_tracking(struct kmem_cache *s, void *object)
410 if (!(s->flags & SLAB_STORE_USER))
413 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
414 print_track("Freed", get_track(s, object, TRACK_FREE));
417 static void print_page_info(struct page *page)
419 printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
420 page, page->objects, page->inuse, page->freelist, page->flags);
424 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
430 vsnprintf(buf, sizeof(buf), fmt, args);
432 printk(KERN_ERR "========================================"
433 "=====================================\n");
434 printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
435 printk(KERN_ERR "----------------------------------------"
436 "-------------------------------------\n\n");
439 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
445 vsnprintf(buf, sizeof(buf), fmt, args);
447 printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
450 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
452 unsigned int off; /* Offset of last byte */
453 u8 *addr = page_address(page);
455 print_tracking(s, p);
457 print_page_info(page);
459 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
460 p, p - addr, get_freepointer(s, p));
463 print_section("Bytes b4", p - 16, 16);
465 print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE));
467 if (s->flags & SLAB_RED_ZONE)
468 print_section("Redzone", p + s->objsize,
469 s->inuse - s->objsize);
472 off = s->offset + sizeof(void *);
476 if (s->flags & SLAB_STORE_USER)
477 off += 2 * sizeof(struct track);
480 /* Beginning of the filler is the free pointer */
481 print_section("Padding", p + off, s->size - off);
486 static void object_err(struct kmem_cache *s, struct page *page,
487 u8 *object, char *reason)
489 slab_bug(s, "%s", reason);
490 print_trailer(s, page, object);
493 static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
499 vsnprintf(buf, sizeof(buf), fmt, args);
501 slab_bug(s, "%s", buf);
502 print_page_info(page);
506 static void init_object(struct kmem_cache *s, void *object, int active)
510 if (s->flags & __OBJECT_POISON) {
511 memset(p, POISON_FREE, s->objsize - 1);
512 p[s->objsize - 1] = POISON_END;
515 if (s->flags & SLAB_RED_ZONE)
516 memset(p + s->objsize,
517 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE,
518 s->inuse - s->objsize);
521 static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
524 if (*start != (u8)value)
532 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
533 void *from, void *to)
535 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
536 memset(from, data, to - from);
539 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
540 u8 *object, char *what,
541 u8 *start, unsigned int value, unsigned int bytes)
546 fault = check_bytes(start, value, bytes);
551 while (end > fault && end[-1] == value)
554 slab_bug(s, "%s overwritten", what);
555 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
556 fault, end - 1, fault[0], value);
557 print_trailer(s, page, object);
559 restore_bytes(s, what, value, fault, end);
567 * Bytes of the object to be managed.
568 * If the freepointer may overlay the object then the free
569 * pointer is the first word of the object.
571 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
574 * object + s->objsize
575 * Padding to reach word boundary. This is also used for Redzoning.
576 * Padding is extended by another word if Redzoning is enabled and
579 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
580 * 0xcc (RED_ACTIVE) for objects in use.
583 * Meta data starts here.
585 * A. Free pointer (if we cannot overwrite object on free)
586 * B. Tracking data for SLAB_STORE_USER
587 * C. Padding to reach required alignment boundary or at mininum
588 * one word if debugging is on to be able to detect writes
589 * before the word boundary.
591 * Padding is done using 0x5a (POISON_INUSE)
594 * Nothing is used beyond s->size.
596 * If slabcaches are merged then the objsize and inuse boundaries are mostly
597 * ignored. And therefore no slab options that rely on these boundaries
598 * may be used with merged slabcaches.
601 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
603 unsigned long off = s->inuse; /* The end of info */
606 /* Freepointer is placed after the object. */
607 off += sizeof(void *);
609 if (s->flags & SLAB_STORE_USER)
610 /* We also have user information there */
611 off += 2 * sizeof(struct track);
616 return check_bytes_and_report(s, page, p, "Object padding",
617 p + off, POISON_INUSE, s->size - off);
620 /* Check the pad bytes at the end of a slab page */
621 static int slab_pad_check(struct kmem_cache *s, struct page *page)
629 if (!(s->flags & SLAB_POISON))
632 start = page_address(page);
633 length = (PAGE_SIZE << compound_order(page));
634 end = start + length;
635 remainder = length % s->size;
639 fault = check_bytes(end - remainder, POISON_INUSE, remainder);
642 while (end > fault && end[-1] == POISON_INUSE)
645 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
646 print_section("Padding", end - remainder, remainder);
648 restore_bytes(s, "slab padding", POISON_INUSE, start, end);
652 static int check_object(struct kmem_cache *s, struct page *page,
653 void *object, int active)
656 u8 *endobject = object + s->objsize;
658 if (s->flags & SLAB_RED_ZONE) {
660 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE;
662 if (!check_bytes_and_report(s, page, object, "Redzone",
663 endobject, red, s->inuse - s->objsize))
666 if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
667 check_bytes_and_report(s, page, p, "Alignment padding",
668 endobject, POISON_INUSE, s->inuse - s->objsize);
672 if (s->flags & SLAB_POISON) {
673 if (!active && (s->flags & __OBJECT_POISON) &&
674 (!check_bytes_and_report(s, page, p, "Poison", p,
675 POISON_FREE, s->objsize - 1) ||
676 !check_bytes_and_report(s, page, p, "Poison",
677 p + s->objsize - 1, POISON_END, 1)))
680 * check_pad_bytes cleans up on its own.
682 check_pad_bytes(s, page, p);
685 if (!s->offset && active)
687 * Object and freepointer overlap. Cannot check
688 * freepointer while object is allocated.
692 /* Check free pointer validity */
693 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
694 object_err(s, page, p, "Freepointer corrupt");
696 * No choice but to zap it and thus lose the remainder
697 * of the free objects in this slab. May cause
698 * another error because the object count is now wrong.
700 set_freepointer(s, p, NULL);
706 static int check_slab(struct kmem_cache *s, struct page *page)
710 VM_BUG_ON(!irqs_disabled());
712 if (!PageSlab(page)) {
713 slab_err(s, page, "Not a valid slab page");
717 maxobj = (PAGE_SIZE << compound_order(page)) / s->size;
718 if (page->objects > maxobj) {
719 slab_err(s, page, "objects %u > max %u",
720 s->name, page->objects, maxobj);
723 if (page->inuse > page->objects) {
724 slab_err(s, page, "inuse %u > max %u",
725 s->name, page->inuse, page->objects);
728 /* Slab_pad_check fixes things up after itself */
729 slab_pad_check(s, page);
734 * Determine if a certain object on a page is on the freelist. Must hold the
735 * slab lock to guarantee that the chains are in a consistent state.
737 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
740 void *fp = page->freelist;
742 unsigned long max_objects;
744 while (fp && nr <= page->objects) {
747 if (!check_valid_pointer(s, page, fp)) {
749 object_err(s, page, object,
750 "Freechain corrupt");
751 set_freepointer(s, object, NULL);
754 slab_err(s, page, "Freepointer corrupt");
755 page->freelist = NULL;
756 page->inuse = page->objects;
757 slab_fix(s, "Freelist cleared");
763 fp = get_freepointer(s, object);
767 max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
768 if (max_objects > MAX_OBJS_PER_PAGE)
769 max_objects = MAX_OBJS_PER_PAGE;
771 if (page->objects != max_objects) {
772 slab_err(s, page, "Wrong number of objects. Found %d but "
773 "should be %d", page->objects, max_objects);
774 page->objects = max_objects;
775 slab_fix(s, "Number of objects adjusted.");
777 if (page->inuse != page->objects - nr) {
778 slab_err(s, page, "Wrong object count. Counter is %d but "
779 "counted were %d", page->inuse, page->objects - nr);
780 page->inuse = page->objects - nr;
781 slab_fix(s, "Object count adjusted.");
783 return search == NULL;
786 static void trace(struct kmem_cache *s, struct page *page, void *object,
789 if (s->flags & SLAB_TRACE) {
790 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
792 alloc ? "alloc" : "free",
797 print_section("Object", (void *)object, s->objsize);
804 * Tracking of fully allocated slabs for debugging purposes.
806 static void add_full(struct kmem_cache_node *n, struct page *page)
808 spin_lock(&n->list_lock);
809 list_add(&page->lru, &n->full);
810 spin_unlock(&n->list_lock);
813 static void remove_full(struct kmem_cache *s, struct page *page)
815 struct kmem_cache_node *n;
817 if (!(s->flags & SLAB_STORE_USER))
820 n = get_node(s, page_to_nid(page));
822 spin_lock(&n->list_lock);
823 list_del(&page->lru);
824 spin_unlock(&n->list_lock);
827 /* Tracking of the number of slabs for debugging purposes */
828 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
830 struct kmem_cache_node *n = get_node(s, node);
832 return atomic_long_read(&n->nr_slabs);
835 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
837 return atomic_long_read(&n->nr_slabs);
840 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
842 struct kmem_cache_node *n = get_node(s, node);
845 * May be called early in order to allocate a slab for the
846 * kmem_cache_node structure. Solve the chicken-egg
847 * dilemma by deferring the increment of the count during
848 * bootstrap (see early_kmem_cache_node_alloc).
850 if (!NUMA_BUILD || n) {
851 atomic_long_inc(&n->nr_slabs);
852 atomic_long_add(objects, &n->total_objects);
855 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
857 struct kmem_cache_node *n = get_node(s, node);
859 atomic_long_dec(&n->nr_slabs);
860 atomic_long_sub(objects, &n->total_objects);
863 /* Object debug checks for alloc/free paths */
864 static void setup_object_debug(struct kmem_cache *s, struct page *page,
867 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
870 init_object(s, object, 0);
871 init_tracking(s, object);
874 static int alloc_debug_processing(struct kmem_cache *s, struct page *page,
875 void *object, unsigned long addr)
877 if (!check_slab(s, page))
880 if (!on_freelist(s, page, object)) {
881 object_err(s, page, object, "Object already allocated");
885 if (!check_valid_pointer(s, page, object)) {
886 object_err(s, page, object, "Freelist Pointer check fails");
890 if (!check_object(s, page, object, 0))
893 /* Success perform special debug activities for allocs */
894 if (s->flags & SLAB_STORE_USER)
895 set_track(s, object, TRACK_ALLOC, addr);
896 trace(s, page, object, 1);
897 init_object(s, object, 1);
901 if (PageSlab(page)) {
903 * If this is a slab page then lets do the best we can
904 * to avoid issues in the future. Marking all objects
905 * as used avoids touching the remaining objects.
907 slab_fix(s, "Marking all objects used");
908 page->inuse = page->objects;
909 page->freelist = NULL;
914 static int free_debug_processing(struct kmem_cache *s, struct page *page,
915 void *object, unsigned long addr)
917 if (!check_slab(s, page))
920 if (!check_valid_pointer(s, page, object)) {
921 slab_err(s, page, "Invalid object pointer 0x%p", object);
925 if (on_freelist(s, page, object)) {
926 object_err(s, page, object, "Object already free");
930 if (!check_object(s, page, object, 1))
933 if (unlikely(s != page->slab)) {
934 if (!PageSlab(page)) {
935 slab_err(s, page, "Attempt to free object(0x%p) "
936 "outside of slab", object);
937 } else if (!page->slab) {
939 "SLUB <none>: no slab for object 0x%p.\n",
943 object_err(s, page, object,
944 "page slab pointer corrupt.");
948 /* Special debug activities for freeing objects */
949 if (!PageSlubFrozen(page) && !page->freelist)
950 remove_full(s, page);
951 if (s->flags & SLAB_STORE_USER)
952 set_track(s, object, TRACK_FREE, addr);
953 trace(s, page, object, 0);
954 init_object(s, object, 0);
958 slab_fix(s, "Object at 0x%p not freed", object);
962 static int __init setup_slub_debug(char *str)
964 slub_debug = DEBUG_DEFAULT_FLAGS;
965 if (*str++ != '=' || !*str)
967 * No options specified. Switch on full debugging.
973 * No options but restriction on slabs. This means full
974 * debugging for slabs matching a pattern.
981 * Switch off all debugging measures.
986 * Determine which debug features should be switched on
988 for (; *str && *str != ','; str++) {
989 switch (tolower(*str)) {
991 slub_debug |= SLAB_DEBUG_FREE;
994 slub_debug |= SLAB_RED_ZONE;
997 slub_debug |= SLAB_POISON;
1000 slub_debug |= SLAB_STORE_USER;
1003 slub_debug |= SLAB_TRACE;
1006 printk(KERN_ERR "slub_debug option '%c' "
1007 "unknown. skipped\n", *str);
1013 slub_debug_slabs = str + 1;
1018 __setup("slub_debug", setup_slub_debug);
1020 static unsigned long kmem_cache_flags(unsigned long objsize,
1021 unsigned long flags, const char *name,
1022 void (*ctor)(void *))
1025 * Enable debugging if selected on the kernel commandline.
1027 if (slub_debug && (!slub_debug_slabs ||
1028 strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)) == 0))
1029 flags |= slub_debug;
1034 static inline void setup_object_debug(struct kmem_cache *s,
1035 struct page *page, void *object) {}
1037 static inline int alloc_debug_processing(struct kmem_cache *s,
1038 struct page *page, void *object, unsigned long addr) { return 0; }
1040 static inline int free_debug_processing(struct kmem_cache *s,
1041 struct page *page, void *object, unsigned long addr) { return 0; }
1043 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1045 static inline int check_object(struct kmem_cache *s, struct page *page,
1046 void *object, int active) { return 1; }
1047 static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
1048 static inline unsigned long kmem_cache_flags(unsigned long objsize,
1049 unsigned long flags, const char *name,
1050 void (*ctor)(void *))
1054 #define slub_debug 0
1056 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1058 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1060 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1062 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1067 * Slab allocation and freeing
1069 static inline struct page *alloc_slab_page(gfp_t flags, int node,
1070 struct kmem_cache_order_objects oo)
1072 int order = oo_order(oo);
1075 return alloc_pages(flags, order);
1077 return alloc_pages_node(node, flags, order);
1080 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1083 struct kmem_cache_order_objects oo = s->oo;
1085 flags |= s->allocflags;
1087 page = alloc_slab_page(flags | __GFP_NOWARN | __GFP_NORETRY, node,
1089 if (unlikely(!page)) {
1092 * Allocation may have failed due to fragmentation.
1093 * Try a lower order alloc if possible
1095 page = alloc_slab_page(flags, node, oo);
1099 stat(get_cpu_slab(s, raw_smp_processor_id()), ORDER_FALLBACK);
1101 page->objects = oo_objects(oo);
1102 mod_zone_page_state(page_zone(page),
1103 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1104 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1110 static void setup_object(struct kmem_cache *s, struct page *page,
1113 setup_object_debug(s, page, object);
1114 if (unlikely(s->ctor))
1118 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1125 BUG_ON(flags & GFP_SLAB_BUG_MASK);
1127 page = allocate_slab(s,
1128 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1132 inc_slabs_node(s, page_to_nid(page), page->objects);
1134 page->flags |= 1 << PG_slab;
1135 if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
1136 SLAB_STORE_USER | SLAB_TRACE))
1137 __SetPageSlubDebug(page);
1139 start = page_address(page);
1141 if (unlikely(s->flags & SLAB_POISON))
1142 memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
1145 for_each_object(p, s, start, page->objects) {
1146 setup_object(s, page, last);
1147 set_freepointer(s, last, p);
1150 setup_object(s, page, last);
1151 set_freepointer(s, last, NULL);
1153 page->freelist = start;
1159 static void __free_slab(struct kmem_cache *s, struct page *page)
1161 int order = compound_order(page);
1162 int pages = 1 << order;
1164 if (unlikely(SLABDEBUG && PageSlubDebug(page))) {
1167 slab_pad_check(s, page);
1168 for_each_object(p, s, page_address(page),
1170 check_object(s, page, p, 0);
1171 __ClearPageSlubDebug(page);
1174 mod_zone_page_state(page_zone(page),
1175 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1176 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1179 __ClearPageSlab(page);
1180 reset_page_mapcount(page);
1181 if (current->reclaim_state)
1182 current->reclaim_state->reclaimed_slab += pages;
1183 __free_pages(page, order);
1186 static void rcu_free_slab(struct rcu_head *h)
1190 page = container_of((struct list_head *)h, struct page, lru);
1191 __free_slab(page->slab, page);
1194 static void free_slab(struct kmem_cache *s, struct page *page)
1196 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1198 * RCU free overloads the RCU head over the LRU
1200 struct rcu_head *head = (void *)&page->lru;
1202 call_rcu(head, rcu_free_slab);
1204 __free_slab(s, page);
1207 static void discard_slab(struct kmem_cache *s, struct page *page)
1209 dec_slabs_node(s, page_to_nid(page), page->objects);
1214 * Per slab locking using the pagelock
1216 static __always_inline void slab_lock(struct page *page)
1218 bit_spin_lock(PG_locked, &page->flags);
1221 static __always_inline void slab_unlock(struct page *page)
1223 __bit_spin_unlock(PG_locked, &page->flags);
1226 static __always_inline int slab_trylock(struct page *page)
1230 rc = bit_spin_trylock(PG_locked, &page->flags);
1235 * Management of partially allocated slabs
1237 static void add_partial(struct kmem_cache_node *n,
1238 struct page *page, int tail)
1240 spin_lock(&n->list_lock);
1243 list_add_tail(&page->lru, &n->partial);
1245 list_add(&page->lru, &n->partial);
1246 spin_unlock(&n->list_lock);
1249 static void remove_partial(struct kmem_cache *s, struct page *page)
1251 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1253 spin_lock(&n->list_lock);
1254 list_del(&page->lru);
1256 spin_unlock(&n->list_lock);
1260 * Lock slab and remove from the partial list.
1262 * Must hold list_lock.
1264 static inline int lock_and_freeze_slab(struct kmem_cache_node *n,
1267 if (slab_trylock(page)) {
1268 list_del(&page->lru);
1270 __SetPageSlubFrozen(page);
1277 * Try to allocate a partial slab from a specific node.
1279 static struct page *get_partial_node(struct kmem_cache_node *n)
1284 * Racy check. If we mistakenly see no partial slabs then we
1285 * just allocate an empty slab. If we mistakenly try to get a
1286 * partial slab and there is none available then get_partials()
1289 if (!n || !n->nr_partial)
1292 spin_lock(&n->list_lock);
1293 list_for_each_entry(page, &n->partial, lru)
1294 if (lock_and_freeze_slab(n, page))
1298 spin_unlock(&n->list_lock);
1303 * Get a page from somewhere. Search in increasing NUMA distances.
1305 static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
1308 struct zonelist *zonelist;
1311 enum zone_type high_zoneidx = gfp_zone(flags);
1315 * The defrag ratio allows a configuration of the tradeoffs between
1316 * inter node defragmentation and node local allocations. A lower
1317 * defrag_ratio increases the tendency to do local allocations
1318 * instead of attempting to obtain partial slabs from other nodes.
1320 * If the defrag_ratio is set to 0 then kmalloc() always
1321 * returns node local objects. If the ratio is higher then kmalloc()
1322 * may return off node objects because partial slabs are obtained
1323 * from other nodes and filled up.
1325 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1326 * defrag_ratio = 1000) then every (well almost) allocation will
1327 * first attempt to defrag slab caches on other nodes. This means
1328 * scanning over all nodes to look for partial slabs which may be
1329 * expensive if we do it every time we are trying to find a slab
1330 * with available objects.
1332 if (!s->remote_node_defrag_ratio ||
1333 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1336 zonelist = node_zonelist(slab_node(current->mempolicy), flags);
1337 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1338 struct kmem_cache_node *n;
1340 n = get_node(s, zone_to_nid(zone));
1342 if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1343 n->nr_partial > s->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 __ClearPageSlubFrozen(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 && PageSlubDebug(page) &&
1389 (s->flags & SLAB_STORE_USER))
1394 stat(c, DEACTIVATE_EMPTY);
1395 if (n->nr_partial < s->min_partial) {
1397 * Adding an empty slab to the partial slabs in order
1398 * to avoid page allocator overhead. This slab needs
1399 * to come after the other slabs with objects in
1400 * so that the others get filled first. That way the
1401 * size of the partial list stays small.
1403 * kmem_cache_shrink can reclaim any empty slabs from
1406 add_partial(n, page, 1);
1410 stat(get_cpu_slab(s, raw_smp_processor_id()), FREE_SLAB);
1411 discard_slab(s, page);
1417 * Remove the cpu slab
1419 static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1421 struct page *page = c->page;
1425 stat(c, DEACTIVATE_REMOTE_FREES);
1427 * Merge cpu freelist into slab freelist. Typically we get here
1428 * because both freelists are empty. So this is unlikely
1431 while (unlikely(c->freelist)) {
1434 tail = 0; /* Hot objects. Put the slab first */
1436 /* Retrieve object from cpu_freelist */
1437 object = c->freelist;
1438 c->freelist = c->freelist[c->offset];
1440 /* And put onto the regular freelist */
1441 object[c->offset] = page->freelist;
1442 page->freelist = object;
1446 unfreeze_slab(s, page, tail);
1449 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1451 stat(c, CPUSLAB_FLUSH);
1453 deactivate_slab(s, c);
1459 * Called from IPI handler with interrupts disabled.
1461 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
1463 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
1465 if (likely(c && c->page))
1469 static void flush_cpu_slab(void *d)
1471 struct kmem_cache *s = d;
1473 __flush_cpu_slab(s, smp_processor_id());
1476 static void flush_all(struct kmem_cache *s)
1478 on_each_cpu(flush_cpu_slab, s, 1);
1482 * Check if the objects in a per cpu structure fit numa
1483 * locality expectations.
1485 static inline int node_match(struct kmem_cache_cpu *c, int node)
1488 if (node != -1 && c->node != node)
1494 static int count_free(struct page *page)
1496 return page->objects - page->inuse;
1499 static unsigned long count_partial(struct kmem_cache_node *n,
1500 int (*get_count)(struct page *))
1502 unsigned long flags;
1503 unsigned long x = 0;
1506 spin_lock_irqsave(&n->list_lock, flags);
1507 list_for_each_entry(page, &n->partial, lru)
1508 x += get_count(page);
1509 spin_unlock_irqrestore(&n->list_lock, flags);
1513 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
1515 #ifdef CONFIG_SLUB_DEBUG
1516 return atomic_long_read(&n->total_objects);
1522 static noinline void
1523 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
1528 "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1530 printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
1531 "default order: %d, min order: %d\n", s->name, s->objsize,
1532 s->size, oo_order(s->oo), oo_order(s->min));
1534 for_each_online_node(node) {
1535 struct kmem_cache_node *n = get_node(s, node);
1536 unsigned long nr_slabs;
1537 unsigned long nr_objs;
1538 unsigned long nr_free;
1543 nr_free = count_partial(n, count_free);
1544 nr_slabs = node_nr_slabs(n);
1545 nr_objs = node_nr_objs(n);
1548 " node %d: slabs: %ld, objs: %ld, free: %ld\n",
1549 node, nr_slabs, nr_objs, nr_free);
1554 * Slow path. The lockless freelist is empty or we need to perform
1557 * Interrupts are disabled.
1559 * Processing is still very fast if new objects have been freed to the
1560 * regular freelist. In that case we simply take over the regular freelist
1561 * as the lockless freelist and zap the regular freelist.
1563 * If that is not working then we fall back to the partial lists. We take the
1564 * first element of the freelist as the object to allocate now and move the
1565 * rest of the freelist to the lockless freelist.
1567 * And if we were unable to get a new slab from the partial slab lists then
1568 * we need to allocate a new slab. This is the slowest path since it involves
1569 * a call to the page allocator and the setup of a new slab.
1571 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
1572 unsigned long addr, struct kmem_cache_cpu *c)
1577 /* We handle __GFP_ZERO in the caller */
1578 gfpflags &= ~__GFP_ZERO;
1584 if (unlikely(!node_match(c, node)))
1587 stat(c, ALLOC_REFILL);
1590 object = c->page->freelist;
1591 if (unlikely(!object))
1593 if (unlikely(SLABDEBUG && PageSlubDebug(c->page)))
1596 c->freelist = object[c->offset];
1597 c->page->inuse = c->page->objects;
1598 c->page->freelist = NULL;
1599 c->node = page_to_nid(c->page);
1601 slab_unlock(c->page);
1602 stat(c, ALLOC_SLOWPATH);
1606 deactivate_slab(s, c);
1609 new = get_partial(s, gfpflags, node);
1612 stat(c, ALLOC_FROM_PARTIAL);
1616 if (gfpflags & __GFP_WAIT)
1619 new = new_slab(s, gfpflags, node);
1621 if (gfpflags & __GFP_WAIT)
1622 local_irq_disable();
1625 c = get_cpu_slab(s, smp_processor_id());
1626 stat(c, ALLOC_SLAB);
1630 __SetPageSlubFrozen(new);
1634 slab_out_of_memory(s, gfpflags, node);
1637 if (!alloc_debug_processing(s, c->page, object, addr))
1641 c->page->freelist = object[c->offset];
1647 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1648 * have the fastpath folded into their functions. So no function call
1649 * overhead for requests that can be satisfied on the fastpath.
1651 * The fastpath works by first checking if the lockless freelist can be used.
1652 * If not then __slab_alloc is called for slow processing.
1654 * Otherwise we can simply pick the next object from the lockless free list.
1656 static __always_inline void *slab_alloc(struct kmem_cache *s,
1657 gfp_t gfpflags, int node, unsigned long addr)
1660 struct kmem_cache_cpu *c;
1661 unsigned long flags;
1662 unsigned int objsize;
1664 lockdep_trace_alloc(gfpflags);
1665 might_sleep_if(gfpflags & __GFP_WAIT);
1667 if (should_failslab(s->objsize, gfpflags))
1670 local_irq_save(flags);
1671 c = get_cpu_slab(s, smp_processor_id());
1672 objsize = c->objsize;
1673 if (unlikely(!c->freelist || !node_match(c, node)))
1675 object = __slab_alloc(s, gfpflags, node, addr, c);
1678 object = c->freelist;
1679 c->freelist = object[c->offset];
1680 stat(c, ALLOC_FASTPATH);
1682 local_irq_restore(flags);
1684 if (unlikely((gfpflags & __GFP_ZERO) && object))
1685 memset(object, 0, objsize);
1690 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
1692 void *ret = slab_alloc(s, gfpflags, -1, _RET_IP_);
1694 trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
1698 EXPORT_SYMBOL(kmem_cache_alloc);
1700 #ifdef CONFIG_KMEMTRACE
1701 void *kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags)
1703 return slab_alloc(s, gfpflags, -1, _RET_IP_);
1705 EXPORT_SYMBOL(kmem_cache_alloc_notrace);
1709 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
1711 void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
1713 trace_kmem_cache_alloc_node(_RET_IP_, ret,
1714 s->objsize, s->size, gfpflags, node);
1718 EXPORT_SYMBOL(kmem_cache_alloc_node);
1721 #ifdef CONFIG_KMEMTRACE
1722 void *kmem_cache_alloc_node_notrace(struct kmem_cache *s,
1726 return slab_alloc(s, gfpflags, node, _RET_IP_);
1728 EXPORT_SYMBOL(kmem_cache_alloc_node_notrace);
1732 * Slow patch handling. This may still be called frequently since objects
1733 * have a longer lifetime than the cpu slabs in most processing loads.
1735 * So we still attempt to reduce cache line usage. Just take the slab
1736 * lock and free the item. If there is no additional partial page
1737 * handling required then we can return immediately.
1739 static void __slab_free(struct kmem_cache *s, struct page *page,
1740 void *x, unsigned long addr, unsigned int offset)
1743 void **object = (void *)x;
1744 struct kmem_cache_cpu *c;
1746 c = get_cpu_slab(s, raw_smp_processor_id());
1747 stat(c, FREE_SLOWPATH);
1750 if (unlikely(SLABDEBUG && PageSlubDebug(page)))
1754 prior = object[offset] = page->freelist;
1755 page->freelist = object;
1758 if (unlikely(PageSlubFrozen(page))) {
1759 stat(c, FREE_FROZEN);
1763 if (unlikely(!page->inuse))
1767 * Objects left in the slab. If it was not on the partial list before
1770 if (unlikely(!prior)) {
1771 add_partial(get_node(s, page_to_nid(page)), page, 1);
1772 stat(c, FREE_ADD_PARTIAL);
1782 * Slab still on the partial list.
1784 remove_partial(s, page);
1785 stat(c, FREE_REMOVE_PARTIAL);
1789 discard_slab(s, page);
1793 if (!free_debug_processing(s, page, x, addr))
1799 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1800 * can perform fastpath freeing without additional function calls.
1802 * The fastpath is only possible if we are freeing to the current cpu slab
1803 * of this processor. This typically the case if we have just allocated
1806 * If fastpath is not possible then fall back to __slab_free where we deal
1807 * with all sorts of special processing.
1809 static __always_inline void slab_free(struct kmem_cache *s,
1810 struct page *page, void *x, unsigned long addr)
1812 void **object = (void *)x;
1813 struct kmem_cache_cpu *c;
1814 unsigned long flags;
1816 local_irq_save(flags);
1817 c = get_cpu_slab(s, smp_processor_id());
1818 debug_check_no_locks_freed(object, c->objsize);
1819 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1820 debug_check_no_obj_freed(object, c->objsize);
1821 if (likely(page == c->page && c->node >= 0)) {
1822 object[c->offset] = c->freelist;
1823 c->freelist = object;
1824 stat(c, FREE_FASTPATH);
1826 __slab_free(s, page, x, addr, c->offset);
1828 local_irq_restore(flags);
1831 void kmem_cache_free(struct kmem_cache *s, void *x)
1835 page = virt_to_head_page(x);
1837 slab_free(s, page, x, _RET_IP_);
1839 trace_kmem_cache_free(_RET_IP_, x);
1841 EXPORT_SYMBOL(kmem_cache_free);
1843 /* Figure out on which slab page the object resides */
1844 static struct page *get_object_page(const void *x)
1846 struct page *page = virt_to_head_page(x);
1848 if (!PageSlab(page))
1855 * Object placement in a slab is made very easy because we always start at
1856 * offset 0. If we tune the size of the object to the alignment then we can
1857 * get the required alignment by putting one properly sized object after
1860 * Notice that the allocation order determines the sizes of the per cpu
1861 * caches. Each processor has always one slab available for allocations.
1862 * Increasing the allocation order reduces the number of times that slabs
1863 * must be moved on and off the partial lists and is therefore a factor in
1868 * Mininum / Maximum order of slab pages. This influences locking overhead
1869 * and slab fragmentation. A higher order reduces the number of partial slabs
1870 * and increases the number of allocations possible without having to
1871 * take the list_lock.
1873 static int slub_min_order;
1874 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
1875 static int slub_min_objects;
1878 * Merge control. If this is set then no merging of slab caches will occur.
1879 * (Could be removed. This was introduced to pacify the merge skeptics.)
1881 static int slub_nomerge;
1884 * Calculate the order of allocation given an slab object size.
1886 * The order of allocation has significant impact on performance and other
1887 * system components. Generally order 0 allocations should be preferred since
1888 * order 0 does not cause fragmentation in the page allocator. Larger objects
1889 * be problematic to put into order 0 slabs because there may be too much
1890 * unused space left. We go to a higher order if more than 1/16th of the slab
1893 * In order to reach satisfactory performance we must ensure that a minimum
1894 * number of objects is in one slab. Otherwise we may generate too much
1895 * activity on the partial lists which requires taking the list_lock. This is
1896 * less a concern for large slabs though which are rarely used.
1898 * slub_max_order specifies the order where we begin to stop considering the
1899 * number of objects in a slab as critical. If we reach slub_max_order then
1900 * we try to keep the page order as low as possible. So we accept more waste
1901 * of space in favor of a small page order.
1903 * Higher order allocations also allow the placement of more objects in a
1904 * slab and thereby reduce object handling overhead. If the user has
1905 * requested a higher mininum order then we start with that one instead of
1906 * the smallest order which will fit the object.
1908 static inline int slab_order(int size, int min_objects,
1909 int max_order, int fract_leftover)
1913 int min_order = slub_min_order;
1915 if ((PAGE_SIZE << min_order) / size > MAX_OBJS_PER_PAGE)
1916 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
1918 for (order = max(min_order,
1919 fls(min_objects * size - 1) - PAGE_SHIFT);
1920 order <= max_order; order++) {
1922 unsigned long slab_size = PAGE_SIZE << order;
1924 if (slab_size < min_objects * size)
1927 rem = slab_size % size;
1929 if (rem <= slab_size / fract_leftover)
1937 static inline int calculate_order(int size)
1945 * Attempt to find best configuration for a slab. This
1946 * works by first attempting to generate a layout with
1947 * the best configuration and backing off gradually.
1949 * First we reduce the acceptable waste in a slab. Then
1950 * we reduce the minimum objects required in a slab.
1952 min_objects = slub_min_objects;
1954 min_objects = 4 * (fls(nr_cpu_ids) + 1);
1955 max_objects = (PAGE_SIZE << slub_max_order)/size;
1956 min_objects = min(min_objects, max_objects);
1958 while (min_objects > 1) {
1960 while (fraction >= 4) {
1961 order = slab_order(size, min_objects,
1962 slub_max_order, fraction);
1963 if (order <= slub_max_order)
1971 * We were unable to place multiple objects in a slab. Now
1972 * lets see if we can place a single object there.
1974 order = slab_order(size, 1, slub_max_order, 1);
1975 if (order <= slub_max_order)
1979 * Doh this slab cannot be placed using slub_max_order.
1981 order = slab_order(size, 1, MAX_ORDER, 1);
1982 if (order < MAX_ORDER)
1988 * Figure out what the alignment of the objects will be.
1990 static unsigned long calculate_alignment(unsigned long flags,
1991 unsigned long align, unsigned long size)
1994 * If the user wants hardware cache aligned objects then follow that
1995 * suggestion if the object is sufficiently large.
1997 * The hardware cache alignment cannot override the specified
1998 * alignment though. If that is greater then use it.
2000 if (flags & SLAB_HWCACHE_ALIGN) {
2001 unsigned long ralign = cache_line_size();
2002 while (size <= ralign / 2)
2004 align = max(align, ralign);
2007 if (align < ARCH_SLAB_MINALIGN)
2008 align = ARCH_SLAB_MINALIGN;
2010 return ALIGN(align, sizeof(void *));
2013 static void init_kmem_cache_cpu(struct kmem_cache *s,
2014 struct kmem_cache_cpu *c)
2019 c->offset = s->offset / sizeof(void *);
2020 c->objsize = s->objsize;
2021 #ifdef CONFIG_SLUB_STATS
2022 memset(c->stat, 0, NR_SLUB_STAT_ITEMS * sizeof(unsigned));
2027 init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
2030 spin_lock_init(&n->list_lock);
2031 INIT_LIST_HEAD(&n->partial);
2032 #ifdef CONFIG_SLUB_DEBUG
2033 atomic_long_set(&n->nr_slabs, 0);
2034 atomic_long_set(&n->total_objects, 0);
2035 INIT_LIST_HEAD(&n->full);
2041 * Per cpu array for per cpu structures.
2043 * The per cpu array places all kmem_cache_cpu structures from one processor
2044 * close together meaning that it becomes possible that multiple per cpu
2045 * structures are contained in one cacheline. This may be particularly
2046 * beneficial for the kmalloc caches.
2048 * A desktop system typically has around 60-80 slabs. With 100 here we are
2049 * likely able to get per cpu structures for all caches from the array defined
2050 * here. We must be able to cover all kmalloc caches during bootstrap.
2052 * If the per cpu array is exhausted then fall back to kmalloc
2053 * of individual cachelines. No sharing is possible then.
2055 #define NR_KMEM_CACHE_CPU 100
2057 static DEFINE_PER_CPU(struct kmem_cache_cpu,
2058 kmem_cache_cpu)[NR_KMEM_CACHE_CPU];
2060 static DEFINE_PER_CPU(struct kmem_cache_cpu *, kmem_cache_cpu_free);
2061 static DECLARE_BITMAP(kmem_cach_cpu_free_init_once, CONFIG_NR_CPUS);
2063 static struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s,
2064 int cpu, gfp_t flags)
2066 struct kmem_cache_cpu *c = per_cpu(kmem_cache_cpu_free, cpu);
2069 per_cpu(kmem_cache_cpu_free, cpu) =
2070 (void *)c->freelist;
2072 /* Table overflow: So allocate ourselves */
2074 ALIGN(sizeof(struct kmem_cache_cpu), cache_line_size()),
2075 flags, cpu_to_node(cpu));
2080 init_kmem_cache_cpu(s, c);
2084 static void free_kmem_cache_cpu(struct kmem_cache_cpu *c, int cpu)
2086 if (c < per_cpu(kmem_cache_cpu, cpu) ||
2087 c >= per_cpu(kmem_cache_cpu, cpu) + NR_KMEM_CACHE_CPU) {
2091 c->freelist = (void *)per_cpu(kmem_cache_cpu_free, cpu);
2092 per_cpu(kmem_cache_cpu_free, cpu) = c;
2095 static void free_kmem_cache_cpus(struct kmem_cache *s)
2099 for_each_online_cpu(cpu) {
2100 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
2103 s->cpu_slab[cpu] = NULL;
2104 free_kmem_cache_cpu(c, cpu);
2109 static int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
2113 for_each_online_cpu(cpu) {
2114 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
2119 c = alloc_kmem_cache_cpu(s, cpu, flags);
2121 free_kmem_cache_cpus(s);
2124 s->cpu_slab[cpu] = c;
2130 * Initialize the per cpu array.
2132 static void init_alloc_cpu_cpu(int cpu)
2136 if (cpumask_test_cpu(cpu, to_cpumask(kmem_cach_cpu_free_init_once)))
2139 for (i = NR_KMEM_CACHE_CPU - 1; i >= 0; i--)
2140 free_kmem_cache_cpu(&per_cpu(kmem_cache_cpu, cpu)[i], cpu);
2142 cpumask_set_cpu(cpu, to_cpumask(kmem_cach_cpu_free_init_once));
2145 static void __init init_alloc_cpu(void)
2149 for_each_online_cpu(cpu)
2150 init_alloc_cpu_cpu(cpu);
2154 static inline void free_kmem_cache_cpus(struct kmem_cache *s) {}
2155 static inline void init_alloc_cpu(void) {}
2157 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
2159 init_kmem_cache_cpu(s, &s->cpu_slab);
2166 * No kmalloc_node yet so do it by hand. We know that this is the first
2167 * slab on the node for this slabcache. There are no concurrent accesses
2170 * Note that this function only works on the kmalloc_node_cache
2171 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2172 * memory on a fresh node that has no slab structures yet.
2174 static void early_kmem_cache_node_alloc(gfp_t gfpflags, int node)
2177 struct kmem_cache_node *n;
2178 unsigned long flags;
2180 BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
2182 page = new_slab(kmalloc_caches, gfpflags, node);
2185 if (page_to_nid(page) != node) {
2186 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2188 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2189 "in order to be able to continue\n");
2194 page->freelist = get_freepointer(kmalloc_caches, n);
2196 kmalloc_caches->node[node] = n;
2197 #ifdef CONFIG_SLUB_DEBUG
2198 init_object(kmalloc_caches, n, 1);
2199 init_tracking(kmalloc_caches, n);
2201 init_kmem_cache_node(n, kmalloc_caches);
2202 inc_slabs_node(kmalloc_caches, node, page->objects);
2205 * lockdep requires consistent irq usage for each lock
2206 * so even though there cannot be a race this early in
2207 * the boot sequence, we still disable irqs.
2209 local_irq_save(flags);
2210 add_partial(n, page, 0);
2211 local_irq_restore(flags);
2214 static void free_kmem_cache_nodes(struct kmem_cache *s)
2218 for_each_node_state(node, N_NORMAL_MEMORY) {
2219 struct kmem_cache_node *n = s->node[node];
2220 if (n && n != &s->local_node)
2221 kmem_cache_free(kmalloc_caches, n);
2222 s->node[node] = NULL;
2226 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2231 if (slab_state >= UP)
2232 local_node = page_to_nid(virt_to_page(s));
2236 for_each_node_state(node, N_NORMAL_MEMORY) {
2237 struct kmem_cache_node *n;
2239 if (local_node == node)
2242 if (slab_state == DOWN) {
2243 early_kmem_cache_node_alloc(gfpflags, node);
2246 n = kmem_cache_alloc_node(kmalloc_caches,
2250 free_kmem_cache_nodes(s);
2256 init_kmem_cache_node(n, s);
2261 static void free_kmem_cache_nodes(struct kmem_cache *s)
2265 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2267 init_kmem_cache_node(&s->local_node, s);
2272 static void set_min_partial(struct kmem_cache *s, unsigned long min)
2274 if (min < MIN_PARTIAL)
2276 else if (min > MAX_PARTIAL)
2278 s->min_partial = min;
2282 * calculate_sizes() determines the order and the distribution of data within
2285 static int calculate_sizes(struct kmem_cache *s, int forced_order)
2287 unsigned long flags = s->flags;
2288 unsigned long size = s->objsize;
2289 unsigned long align = s->align;
2293 * Round up object size to the next word boundary. We can only
2294 * place the free pointer at word boundaries and this determines
2295 * the possible location of the free pointer.
2297 size = ALIGN(size, sizeof(void *));
2299 #ifdef CONFIG_SLUB_DEBUG
2301 * Determine if we can poison the object itself. If the user of
2302 * the slab may touch the object after free or before allocation
2303 * then we should never poison the object itself.
2305 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2307 s->flags |= __OBJECT_POISON;
2309 s->flags &= ~__OBJECT_POISON;
2313 * If we are Redzoning then check if there is some space between the
2314 * end of the object and the free pointer. If not then add an
2315 * additional word to have some bytes to store Redzone information.
2317 if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2318 size += sizeof(void *);
2322 * With that we have determined the number of bytes in actual use
2323 * by the object. This is the potential offset to the free pointer.
2327 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2330 * Relocate free pointer after the object if it is not
2331 * permitted to overwrite the first word of the object on
2334 * This is the case if we do RCU, have a constructor or
2335 * destructor or are poisoning the objects.
2338 size += sizeof(void *);
2341 #ifdef CONFIG_SLUB_DEBUG
2342 if (flags & SLAB_STORE_USER)
2344 * Need to store information about allocs and frees after
2347 size += 2 * sizeof(struct track);
2349 if (flags & SLAB_RED_ZONE)
2351 * Add some empty padding so that we can catch
2352 * overwrites from earlier objects rather than let
2353 * tracking information or the free pointer be
2354 * corrupted if a user writes before the start
2357 size += sizeof(void *);
2361 * Determine the alignment based on various parameters that the
2362 * user specified and the dynamic determination of cache line size
2365 align = calculate_alignment(flags, align, s->objsize);
2368 * SLUB stores one object immediately after another beginning from
2369 * offset 0. In order to align the objects we have to simply size
2370 * each object to conform to the alignment.
2372 size = ALIGN(size, align);
2374 if (forced_order >= 0)
2375 order = forced_order;
2377 order = calculate_order(size);
2384 s->allocflags |= __GFP_COMP;
2386 if (s->flags & SLAB_CACHE_DMA)
2387 s->allocflags |= SLUB_DMA;
2389 if (s->flags & SLAB_RECLAIM_ACCOUNT)
2390 s->allocflags |= __GFP_RECLAIMABLE;
2393 * Determine the number of objects per slab
2395 s->oo = oo_make(order, size);
2396 s->min = oo_make(get_order(size), size);
2397 if (oo_objects(s->oo) > oo_objects(s->max))
2400 return !!oo_objects(s->oo);
2404 static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
2405 const char *name, size_t size,
2406 size_t align, unsigned long flags,
2407 void (*ctor)(void *))
2409 memset(s, 0, kmem_size);
2414 s->flags = kmem_cache_flags(size, flags, name, ctor);
2416 if (!calculate_sizes(s, -1))
2420 * The larger the object size is, the more pages we want on the partial
2421 * list to avoid pounding the page allocator excessively.
2423 set_min_partial(s, ilog2(s->size));
2426 s->remote_node_defrag_ratio = 1000;
2428 if (!init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
2431 if (alloc_kmem_cache_cpus(s, gfpflags & ~SLUB_DMA))
2433 free_kmem_cache_nodes(s);
2435 if (flags & SLAB_PANIC)
2436 panic("Cannot create slab %s size=%lu realsize=%u "
2437 "order=%u offset=%u flags=%lx\n",
2438 s->name, (unsigned long)size, s->size, oo_order(s->oo),
2444 * Check if a given pointer is valid
2446 int kmem_ptr_validate(struct kmem_cache *s, const void *object)
2450 page = get_object_page(object);
2452 if (!page || s != page->slab)
2453 /* No slab or wrong slab */
2456 if (!check_valid_pointer(s, page, object))
2460 * We could also check if the object is on the slabs freelist.
2461 * But this would be too expensive and it seems that the main
2462 * purpose of kmem_ptr_valid() is to check if the object belongs
2463 * to a certain slab.
2467 EXPORT_SYMBOL(kmem_ptr_validate);
2470 * Determine the size of a slab object
2472 unsigned int kmem_cache_size(struct kmem_cache *s)
2476 EXPORT_SYMBOL(kmem_cache_size);
2478 const char *kmem_cache_name(struct kmem_cache *s)
2482 EXPORT_SYMBOL(kmem_cache_name);
2484 static void list_slab_objects(struct kmem_cache *s, struct page *page,
2487 #ifdef CONFIG_SLUB_DEBUG
2488 void *addr = page_address(page);
2490 DECLARE_BITMAP(map, page->objects);
2492 bitmap_zero(map, page->objects);
2493 slab_err(s, page, "%s", text);
2495 for_each_free_object(p, s, page->freelist)
2496 set_bit(slab_index(p, s, addr), map);
2498 for_each_object(p, s, addr, page->objects) {
2500 if (!test_bit(slab_index(p, s, addr), map)) {
2501 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
2503 print_tracking(s, p);
2511 * Attempt to free all partial slabs on a node.
2513 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
2515 unsigned long flags;
2516 struct page *page, *h;
2518 spin_lock_irqsave(&n->list_lock, flags);
2519 list_for_each_entry_safe(page, h, &n->partial, lru) {
2521 list_del(&page->lru);
2522 discard_slab(s, page);
2525 list_slab_objects(s, page,
2526 "Objects remaining on kmem_cache_close()");
2529 spin_unlock_irqrestore(&n->list_lock, flags);
2533 * Release all resources used by a slab cache.
2535 static inline int kmem_cache_close(struct kmem_cache *s)
2541 /* Attempt to free all objects */
2542 free_kmem_cache_cpus(s);
2543 for_each_node_state(node, N_NORMAL_MEMORY) {
2544 struct kmem_cache_node *n = get_node(s, node);
2547 if (n->nr_partial || slabs_node(s, node))
2550 free_kmem_cache_nodes(s);
2555 * Close a cache and release the kmem_cache structure
2556 * (must be used for caches created using kmem_cache_create)
2558 void kmem_cache_destroy(struct kmem_cache *s)
2560 down_write(&slub_lock);
2564 up_write(&slub_lock);
2565 if (kmem_cache_close(s)) {
2566 printk(KERN_ERR "SLUB %s: %s called for cache that "
2567 "still has objects.\n", s->name, __func__);
2570 sysfs_slab_remove(s);
2572 up_write(&slub_lock);
2574 EXPORT_SYMBOL(kmem_cache_destroy);
2576 /********************************************************************
2578 *******************************************************************/
2580 struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT] __cacheline_aligned;
2581 EXPORT_SYMBOL(kmalloc_caches);
2583 static int __init setup_slub_min_order(char *str)
2585 get_option(&str, &slub_min_order);
2590 __setup("slub_min_order=", setup_slub_min_order);
2592 static int __init setup_slub_max_order(char *str)
2594 get_option(&str, &slub_max_order);
2595 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
2600 __setup("slub_max_order=", setup_slub_max_order);
2602 static int __init setup_slub_min_objects(char *str)
2604 get_option(&str, &slub_min_objects);
2609 __setup("slub_min_objects=", setup_slub_min_objects);
2611 static int __init setup_slub_nomerge(char *str)
2617 __setup("slub_nomerge", setup_slub_nomerge);
2619 static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
2620 const char *name, int size, gfp_t gfp_flags)
2622 unsigned int flags = 0;
2624 if (gfp_flags & SLUB_DMA)
2625 flags = SLAB_CACHE_DMA;
2627 down_write(&slub_lock);
2628 if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
2632 list_add(&s->list, &slab_caches);
2633 up_write(&slub_lock);
2634 if (sysfs_slab_add(s))
2639 panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
2642 #ifdef CONFIG_ZONE_DMA
2643 static struct kmem_cache *kmalloc_caches_dma[SLUB_PAGE_SHIFT];
2645 static void sysfs_add_func(struct work_struct *w)
2647 struct kmem_cache *s;
2649 down_write(&slub_lock);
2650 list_for_each_entry(s, &slab_caches, list) {
2651 if (s->flags & __SYSFS_ADD_DEFERRED) {
2652 s->flags &= ~__SYSFS_ADD_DEFERRED;
2656 up_write(&slub_lock);
2659 static DECLARE_WORK(sysfs_add_work, sysfs_add_func);
2661 static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
2663 struct kmem_cache *s;
2667 s = kmalloc_caches_dma[index];
2671 /* Dynamically create dma cache */
2672 if (flags & __GFP_WAIT)
2673 down_write(&slub_lock);
2675 if (!down_write_trylock(&slub_lock))
2679 if (kmalloc_caches_dma[index])
2682 realsize = kmalloc_caches[index].objsize;
2683 text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
2684 (unsigned int)realsize);
2685 s = kmalloc(kmem_size, flags & ~SLUB_DMA);
2687 if (!s || !text || !kmem_cache_open(s, flags, text,
2688 realsize, ARCH_KMALLOC_MINALIGN,
2689 SLAB_CACHE_DMA|__SYSFS_ADD_DEFERRED, NULL)) {
2695 list_add(&s->list, &slab_caches);
2696 kmalloc_caches_dma[index] = s;
2698 schedule_work(&sysfs_add_work);
2701 up_write(&slub_lock);
2703 return kmalloc_caches_dma[index];
2708 * Conversion table for small slabs sizes / 8 to the index in the
2709 * kmalloc array. This is necessary for slabs < 192 since we have non power
2710 * of two cache sizes there. The size of larger slabs can be determined using
2713 static s8 size_index[24] = {
2740 static struct kmem_cache *get_slab(size_t size, gfp_t flags)
2746 return ZERO_SIZE_PTR;
2748 index = size_index[(size - 1) / 8];
2750 index = fls(size - 1);
2752 #ifdef CONFIG_ZONE_DMA
2753 if (unlikely((flags & SLUB_DMA)))
2754 return dma_kmalloc_cache(index, flags);
2757 return &kmalloc_caches[index];
2760 void *__kmalloc(size_t size, gfp_t flags)
2762 struct kmem_cache *s;
2765 if (unlikely(size > SLUB_MAX_SIZE))
2766 return kmalloc_large(size, flags);
2768 s = get_slab(size, flags);
2770 if (unlikely(ZERO_OR_NULL_PTR(s)))
2773 ret = slab_alloc(s, flags, -1, _RET_IP_);
2775 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
2779 EXPORT_SYMBOL(__kmalloc);
2781 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
2783 struct page *page = alloc_pages_node(node, flags | __GFP_COMP,
2787 return page_address(page);
2793 void *__kmalloc_node(size_t size, gfp_t flags, int node)
2795 struct kmem_cache *s;
2798 if (unlikely(size > SLUB_MAX_SIZE)) {
2799 ret = kmalloc_large_node(size, flags, node);
2801 trace_kmalloc_node(_RET_IP_, ret,
2802 size, PAGE_SIZE << get_order(size),
2808 s = get_slab(size, flags);
2810 if (unlikely(ZERO_OR_NULL_PTR(s)))
2813 ret = slab_alloc(s, flags, node, _RET_IP_);
2815 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
2819 EXPORT_SYMBOL(__kmalloc_node);
2822 size_t ksize(const void *object)
2825 struct kmem_cache *s;
2827 if (unlikely(object == ZERO_SIZE_PTR))
2830 page = virt_to_head_page(object);
2832 if (unlikely(!PageSlab(page))) {
2833 WARN_ON(!PageCompound(page));
2834 return PAGE_SIZE << compound_order(page);
2838 #ifdef CONFIG_SLUB_DEBUG
2840 * Debugging requires use of the padding between object
2841 * and whatever may come after it.
2843 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
2848 * If we have the need to store the freelist pointer
2849 * back there or track user information then we can
2850 * only use the space before that information.
2852 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
2855 * Else we can use all the padding etc for the allocation
2859 EXPORT_SYMBOL(ksize);
2861 void kfree(const void *x)
2864 void *object = (void *)x;
2866 trace_kfree(_RET_IP_, x);
2868 if (unlikely(ZERO_OR_NULL_PTR(x)))
2871 page = virt_to_head_page(x);
2872 if (unlikely(!PageSlab(page))) {
2873 BUG_ON(!PageCompound(page));
2877 slab_free(page->slab, page, object, _RET_IP_);
2879 EXPORT_SYMBOL(kfree);
2882 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2883 * the remaining slabs by the number of items in use. The slabs with the
2884 * most items in use come first. New allocations will then fill those up
2885 * and thus they can be removed from the partial lists.
2887 * The slabs with the least items are placed last. This results in them
2888 * being allocated from last increasing the chance that the last objects
2889 * are freed in them.
2891 int kmem_cache_shrink(struct kmem_cache *s)
2895 struct kmem_cache_node *n;
2898 int objects = oo_objects(s->max);
2899 struct list_head *slabs_by_inuse =
2900 kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
2901 unsigned long flags;
2903 if (!slabs_by_inuse)
2907 for_each_node_state(node, N_NORMAL_MEMORY) {
2908 n = get_node(s, node);
2913 for (i = 0; i < objects; i++)
2914 INIT_LIST_HEAD(slabs_by_inuse + i);
2916 spin_lock_irqsave(&n->list_lock, flags);
2919 * Build lists indexed by the items in use in each slab.
2921 * Note that concurrent frees may occur while we hold the
2922 * list_lock. page->inuse here is the upper limit.
2924 list_for_each_entry_safe(page, t, &n->partial, lru) {
2925 if (!page->inuse && slab_trylock(page)) {
2927 * Must hold slab lock here because slab_free
2928 * may have freed the last object and be
2929 * waiting to release the slab.
2931 list_del(&page->lru);
2934 discard_slab(s, page);
2936 list_move(&page->lru,
2937 slabs_by_inuse + page->inuse);
2942 * Rebuild the partial list with the slabs filled up most
2943 * first and the least used slabs at the end.
2945 for (i = objects - 1; i >= 0; i--)
2946 list_splice(slabs_by_inuse + i, n->partial.prev);
2948 spin_unlock_irqrestore(&n->list_lock, flags);
2951 kfree(slabs_by_inuse);
2954 EXPORT_SYMBOL(kmem_cache_shrink);
2956 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
2957 static int slab_mem_going_offline_callback(void *arg)
2959 struct kmem_cache *s;
2961 down_read(&slub_lock);
2962 list_for_each_entry(s, &slab_caches, list)
2963 kmem_cache_shrink(s);
2964 up_read(&slub_lock);
2969 static void slab_mem_offline_callback(void *arg)
2971 struct kmem_cache_node *n;
2972 struct kmem_cache *s;
2973 struct memory_notify *marg = arg;
2976 offline_node = marg->status_change_nid;
2979 * If the node still has available memory. we need kmem_cache_node
2982 if (offline_node < 0)
2985 down_read(&slub_lock);
2986 list_for_each_entry(s, &slab_caches, list) {
2987 n = get_node(s, offline_node);
2990 * if n->nr_slabs > 0, slabs still exist on the node
2991 * that is going down. We were unable to free them,
2992 * and offline_pages() function shoudn't call this
2993 * callback. So, we must fail.
2995 BUG_ON(slabs_node(s, offline_node));
2997 s->node[offline_node] = NULL;
2998 kmem_cache_free(kmalloc_caches, n);
3001 up_read(&slub_lock);
3004 static int slab_mem_going_online_callback(void *arg)
3006 struct kmem_cache_node *n;
3007 struct kmem_cache *s;
3008 struct memory_notify *marg = arg;
3009 int nid = marg->status_change_nid;
3013 * If the node's memory is already available, then kmem_cache_node is
3014 * already created. Nothing to do.
3020 * We are bringing a node online. No memory is available yet. We must
3021 * allocate a kmem_cache_node structure in order to bring the node
3024 down_read(&slub_lock);
3025 list_for_each_entry(s, &slab_caches, list) {
3027 * XXX: kmem_cache_alloc_node will fallback to other nodes
3028 * since memory is not yet available from the node that
3031 n = kmem_cache_alloc(kmalloc_caches, GFP_KERNEL);
3036 init_kmem_cache_node(n, s);
3040 up_read(&slub_lock);
3044 static int slab_memory_callback(struct notifier_block *self,
3045 unsigned long action, void *arg)
3050 case MEM_GOING_ONLINE:
3051 ret = slab_mem_going_online_callback(arg);
3053 case MEM_GOING_OFFLINE:
3054 ret = slab_mem_going_offline_callback(arg);
3057 case MEM_CANCEL_ONLINE:
3058 slab_mem_offline_callback(arg);
3061 case MEM_CANCEL_OFFLINE:
3065 ret = notifier_from_errno(ret);
3071 #endif /* CONFIG_MEMORY_HOTPLUG */
3073 /********************************************************************
3074 * Basic setup of slabs
3075 *******************************************************************/
3077 void __init kmem_cache_init(void)
3086 * Must first have the slab cache available for the allocations of the
3087 * struct kmem_cache_node's. There is special bootstrap code in
3088 * kmem_cache_open for slab_state == DOWN.
3090 create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node",
3091 sizeof(struct kmem_cache_node), GFP_KERNEL);
3092 kmalloc_caches[0].refcount = -1;
3095 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3098 /* Able to allocate the per node structures */
3099 slab_state = PARTIAL;
3101 /* Caches that are not of the two-to-the-power-of size */
3102 if (KMALLOC_MIN_SIZE <= 64) {
3103 create_kmalloc_cache(&kmalloc_caches[1],
3104 "kmalloc-96", 96, GFP_KERNEL);
3106 create_kmalloc_cache(&kmalloc_caches[2],
3107 "kmalloc-192", 192, GFP_KERNEL);
3111 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3112 create_kmalloc_cache(&kmalloc_caches[i],
3113 "kmalloc", 1 << i, GFP_KERNEL);
3119 * Patch up the size_index table if we have strange large alignment
3120 * requirements for the kmalloc array. This is only the case for
3121 * MIPS it seems. The standard arches will not generate any code here.
3123 * Largest permitted alignment is 256 bytes due to the way we
3124 * handle the index determination for the smaller caches.
3126 * Make sure that nothing crazy happens if someone starts tinkering
3127 * around with ARCH_KMALLOC_MINALIGN
3129 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3130 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3132 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8)
3133 size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW;
3135 if (KMALLOC_MIN_SIZE == 128) {
3137 * The 192 byte sized cache is not used if the alignment
3138 * is 128 byte. Redirect kmalloc to use the 256 byte cache
3141 for (i = 128 + 8; i <= 192; i += 8)
3142 size_index[(i - 1) / 8] = 8;
3147 /* Provide the correct kmalloc names now that the caches are up */
3148 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++)
3149 kmalloc_caches[i]. name =
3150 kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i);
3153 register_cpu_notifier(&slab_notifier);
3154 kmem_size = offsetof(struct kmem_cache, cpu_slab) +
3155 nr_cpu_ids * sizeof(struct kmem_cache_cpu *);
3157 kmem_size = sizeof(struct kmem_cache);
3161 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3162 " CPUs=%d, Nodes=%d\n",
3163 caches, cache_line_size(),
3164 slub_min_order, slub_max_order, slub_min_objects,
3165 nr_cpu_ids, nr_node_ids);
3169 * Find a mergeable slab cache
3171 static int slab_unmergeable(struct kmem_cache *s)
3173 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3180 * We may have set a slab to be unmergeable during bootstrap.
3182 if (s->refcount < 0)
3188 static struct kmem_cache *find_mergeable(size_t size,
3189 size_t align, unsigned long flags, const char *name,
3190 void (*ctor)(void *))
3192 struct kmem_cache *s;
3194 if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3200 size = ALIGN(size, sizeof(void *));
3201 align = calculate_alignment(flags, align, size);
3202 size = ALIGN(size, align);
3203 flags = kmem_cache_flags(size, flags, name, NULL);
3205 list_for_each_entry(s, &slab_caches, list) {
3206 if (slab_unmergeable(s))
3212 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3215 * Check if alignment is compatible.
3216 * Courtesy of Adrian Drzewiecki
3218 if ((s->size & ~(align - 1)) != s->size)
3221 if (s->size - size >= sizeof(void *))
3229 struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3230 size_t align, unsigned long flags, void (*ctor)(void *))
3232 struct kmem_cache *s;
3234 down_write(&slub_lock);
3235 s = find_mergeable(size, align, flags, name, ctor);
3241 * Adjust the object sizes so that we clear
3242 * the complete object on kzalloc.
3244 s->objsize = max(s->objsize, (int)size);
3247 * And then we need to update the object size in the
3248 * per cpu structures
3250 for_each_online_cpu(cpu)
3251 get_cpu_slab(s, cpu)->objsize = s->objsize;
3253 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3254 up_write(&slub_lock);
3256 if (sysfs_slab_alias(s, name)) {
3257 down_write(&slub_lock);
3259 up_write(&slub_lock);
3265 s = kmalloc(kmem_size, GFP_KERNEL);
3267 if (kmem_cache_open(s, GFP_KERNEL, name,
3268 size, align, flags, ctor)) {
3269 list_add(&s->list, &slab_caches);
3270 up_write(&slub_lock);
3271 if (sysfs_slab_add(s)) {
3272 down_write(&slub_lock);
3274 up_write(&slub_lock);
3282 up_write(&slub_lock);
3285 if (flags & SLAB_PANIC)
3286 panic("Cannot create slabcache %s\n", name);
3291 EXPORT_SYMBOL(kmem_cache_create);
3295 * Use the cpu notifier to insure that the cpu slabs are flushed when
3298 static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3299 unsigned long action, void *hcpu)
3301 long cpu = (long)hcpu;
3302 struct kmem_cache *s;
3303 unsigned long flags;
3306 case CPU_UP_PREPARE:
3307 case CPU_UP_PREPARE_FROZEN:
3308 init_alloc_cpu_cpu(cpu);
3309 down_read(&slub_lock);
3310 list_for_each_entry(s, &slab_caches, list)
3311 s->cpu_slab[cpu] = alloc_kmem_cache_cpu(s, cpu,
3313 up_read(&slub_lock);
3316 case CPU_UP_CANCELED:
3317 case CPU_UP_CANCELED_FROZEN:
3319 case CPU_DEAD_FROZEN:
3320 down_read(&slub_lock);
3321 list_for_each_entry(s, &slab_caches, list) {
3322 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3324 local_irq_save(flags);
3325 __flush_cpu_slab(s, cpu);
3326 local_irq_restore(flags);
3327 free_kmem_cache_cpu(c, cpu);
3328 s->cpu_slab[cpu] = NULL;
3330 up_read(&slub_lock);
3338 static struct notifier_block __cpuinitdata slab_notifier = {
3339 .notifier_call = slab_cpuup_callback
3344 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
3346 struct kmem_cache *s;
3349 if (unlikely(size > SLUB_MAX_SIZE))
3350 return kmalloc_large(size, gfpflags);
3352 s = get_slab(size, gfpflags);
3354 if (unlikely(ZERO_OR_NULL_PTR(s)))
3357 ret = slab_alloc(s, gfpflags, -1, caller);
3359 /* Honor the call site pointer we recieved. */
3360 trace_kmalloc(caller, ret, size, s->size, gfpflags);
3365 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3366 int node, unsigned long caller)
3368 struct kmem_cache *s;
3371 if (unlikely(size > SLUB_MAX_SIZE))
3372 return kmalloc_large_node(size, gfpflags, node);
3374 s = get_slab(size, gfpflags);
3376 if (unlikely(ZERO_OR_NULL_PTR(s)))
3379 ret = slab_alloc(s, gfpflags, node, caller);
3381 /* Honor the call site pointer we recieved. */
3382 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
3387 #ifdef CONFIG_SLUB_DEBUG
3388 static int count_inuse(struct page *page)
3393 static int count_total(struct page *page)
3395 return page->objects;
3398 static int validate_slab(struct kmem_cache *s, struct page *page,
3402 void *addr = page_address(page);
3404 if (!check_slab(s, page) ||
3405 !on_freelist(s, page, NULL))
3408 /* Now we know that a valid freelist exists */
3409 bitmap_zero(map, page->objects);
3411 for_each_free_object(p, s, page->freelist) {
3412 set_bit(slab_index(p, s, addr), map);
3413 if (!check_object(s, page, p, 0))
3417 for_each_object(p, s, addr, page->objects)
3418 if (!test_bit(slab_index(p, s, addr), map))
3419 if (!check_object(s, page, p, 1))
3424 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3427 if (slab_trylock(page)) {
3428 validate_slab(s, page, map);
3431 printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
3434 if (s->flags & DEBUG_DEFAULT_FLAGS) {
3435 if (!PageSlubDebug(page))
3436 printk(KERN_ERR "SLUB %s: SlubDebug not set "
3437 "on slab 0x%p\n", s->name, page);
3439 if (PageSlubDebug(page))
3440 printk(KERN_ERR "SLUB %s: SlubDebug set on "
3441 "slab 0x%p\n", s->name, page);
3445 static int validate_slab_node(struct kmem_cache *s,
3446 struct kmem_cache_node *n, unsigned long *map)
3448 unsigned long count = 0;
3450 unsigned long flags;
3452 spin_lock_irqsave(&n->list_lock, flags);
3454 list_for_each_entry(page, &n->partial, lru) {
3455 validate_slab_slab(s, page, map);
3458 if (count != n->nr_partial)
3459 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3460 "counter=%ld\n", s->name, count, n->nr_partial);
3462 if (!(s->flags & SLAB_STORE_USER))
3465 list_for_each_entry(page, &n->full, lru) {
3466 validate_slab_slab(s, page, map);
3469 if (count != atomic_long_read(&n->nr_slabs))
3470 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3471 "counter=%ld\n", s->name, count,
3472 atomic_long_read(&n->nr_slabs));
3475 spin_unlock_irqrestore(&n->list_lock, flags);
3479 static long validate_slab_cache(struct kmem_cache *s)
3482 unsigned long count = 0;
3483 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
3484 sizeof(unsigned long), GFP_KERNEL);
3490 for_each_node_state(node, N_NORMAL_MEMORY) {
3491 struct kmem_cache_node *n = get_node(s, node);
3493 count += validate_slab_node(s, n, map);
3499 #ifdef SLUB_RESILIENCY_TEST
3500 static void resiliency_test(void)
3504 printk(KERN_ERR "SLUB resiliency testing\n");
3505 printk(KERN_ERR "-----------------------\n");
3506 printk(KERN_ERR "A. Corruption after allocation\n");
3508 p = kzalloc(16, GFP_KERNEL);
3510 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
3511 " 0x12->0x%p\n\n", p + 16);
3513 validate_slab_cache(kmalloc_caches + 4);
3515 /* Hmmm... The next two are dangerous */
3516 p = kzalloc(32, GFP_KERNEL);
3517 p[32 + sizeof(void *)] = 0x34;
3518 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
3519 " 0x34 -> -0x%p\n", p);
3521 "If allocated object is overwritten then not detectable\n\n");
3523 validate_slab_cache(kmalloc_caches + 5);
3524 p = kzalloc(64, GFP_KERNEL);
3525 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
3527 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
3530 "If allocated object is overwritten then not detectable\n\n");
3531 validate_slab_cache(kmalloc_caches + 6);
3533 printk(KERN_ERR "\nB. Corruption after free\n");
3534 p = kzalloc(128, GFP_KERNEL);
3537 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
3538 validate_slab_cache(kmalloc_caches + 7);
3540 p = kzalloc(256, GFP_KERNEL);
3543 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
3545 validate_slab_cache(kmalloc_caches + 8);
3547 p = kzalloc(512, GFP_KERNEL);
3550 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
3551 validate_slab_cache(kmalloc_caches + 9);
3554 static void resiliency_test(void) {};
3558 * Generate lists of code addresses where slabcache objects are allocated
3563 unsigned long count;
3570 DECLARE_BITMAP(cpus, NR_CPUS);
3576 unsigned long count;
3577 struct location *loc;
3580 static void free_loc_track(struct loc_track *t)
3583 free_pages((unsigned long)t->loc,
3584 get_order(sizeof(struct location) * t->max));
3587 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
3592 order = get_order(sizeof(struct location) * max);
3594 l = (void *)__get_free_pages(flags, order);
3599 memcpy(l, t->loc, sizeof(struct location) * t->count);
3607 static int add_location(struct loc_track *t, struct kmem_cache *s,
3608 const struct track *track)
3610 long start, end, pos;
3612 unsigned long caddr;
3613 unsigned long age = jiffies - track->when;
3619 pos = start + (end - start + 1) / 2;
3622 * There is nothing at "end". If we end up there
3623 * we need to add something to before end.
3628 caddr = t->loc[pos].addr;
3629 if (track->addr == caddr) {
3635 if (age < l->min_time)
3637 if (age > l->max_time)
3640 if (track->pid < l->min_pid)
3641 l->min_pid = track->pid;
3642 if (track->pid > l->max_pid)
3643 l->max_pid = track->pid;
3645 cpumask_set_cpu(track->cpu,
3646 to_cpumask(l->cpus));
3648 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3652 if (track->addr < caddr)
3659 * Not found. Insert new tracking element.
3661 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
3667 (t->count - pos) * sizeof(struct location));
3670 l->addr = track->addr;
3674 l->min_pid = track->pid;
3675 l->max_pid = track->pid;
3676 cpumask_clear(to_cpumask(l->cpus));
3677 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
3678 nodes_clear(l->nodes);
3679 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3683 static void process_slab(struct loc_track *t, struct kmem_cache *s,
3684 struct page *page, enum track_item alloc)
3686 void *addr = page_address(page);
3687 DECLARE_BITMAP(map, page->objects);
3690 bitmap_zero(map, page->objects);
3691 for_each_free_object(p, s, page->freelist)
3692 set_bit(slab_index(p, s, addr), map);
3694 for_each_object(p, s, addr, page->objects)
3695 if (!test_bit(slab_index(p, s, addr), map))
3696 add_location(t, s, get_track(s, p, alloc));
3699 static int list_locations(struct kmem_cache *s, char *buf,
3700 enum track_item alloc)
3704 struct loc_track t = { 0, 0, NULL };
3707 if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
3709 return sprintf(buf, "Out of memory\n");
3711 /* Push back cpu slabs */
3714 for_each_node_state(node, N_NORMAL_MEMORY) {
3715 struct kmem_cache_node *n = get_node(s, node);
3716 unsigned long flags;
3719 if (!atomic_long_read(&n->nr_slabs))
3722 spin_lock_irqsave(&n->list_lock, flags);
3723 list_for_each_entry(page, &n->partial, lru)
3724 process_slab(&t, s, page, alloc);
3725 list_for_each_entry(page, &n->full, lru)
3726 process_slab(&t, s, page, alloc);
3727 spin_unlock_irqrestore(&n->list_lock, flags);
3730 for (i = 0; i < t.count; i++) {
3731 struct location *l = &t.loc[i];
3733 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
3735 len += sprintf(buf + len, "%7ld ", l->count);
3738 len += sprint_symbol(buf + len, (unsigned long)l->addr);
3740 len += sprintf(buf + len, "<not-available>");
3742 if (l->sum_time != l->min_time) {
3743 len += sprintf(buf + len, " age=%ld/%ld/%ld",
3745 (long)div_u64(l->sum_time, l->count),
3748 len += sprintf(buf + len, " age=%ld",
3751 if (l->min_pid != l->max_pid)
3752 len += sprintf(buf + len, " pid=%ld-%ld",
3753 l->min_pid, l->max_pid);
3755 len += sprintf(buf + len, " pid=%ld",
3758 if (num_online_cpus() > 1 &&
3759 !cpumask_empty(to_cpumask(l->cpus)) &&
3760 len < PAGE_SIZE - 60) {
3761 len += sprintf(buf + len, " cpus=");
3762 len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3763 to_cpumask(l->cpus));
3766 if (num_online_nodes() > 1 && !nodes_empty(l->nodes) &&
3767 len < PAGE_SIZE - 60) {
3768 len += sprintf(buf + len, " nodes=");
3769 len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3773 len += sprintf(buf + len, "\n");
3778 len += sprintf(buf, "No data\n");
3782 enum slab_stat_type {
3783 SL_ALL, /* All slabs */
3784 SL_PARTIAL, /* Only partially allocated slabs */
3785 SL_CPU, /* Only slabs used for cpu caches */
3786 SL_OBJECTS, /* Determine allocated objects not slabs */
3787 SL_TOTAL /* Determine object capacity not slabs */
3790 #define SO_ALL (1 << SL_ALL)
3791 #define SO_PARTIAL (1 << SL_PARTIAL)
3792 #define SO_CPU (1 << SL_CPU)
3793 #define SO_OBJECTS (1 << SL_OBJECTS)
3794 #define SO_TOTAL (1 << SL_TOTAL)
3796 static ssize_t show_slab_objects(struct kmem_cache *s,
3797 char *buf, unsigned long flags)
3799 unsigned long total = 0;
3802 unsigned long *nodes;
3803 unsigned long *per_cpu;
3805 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
3808 per_cpu = nodes + nr_node_ids;
3810 if (flags & SO_CPU) {
3813 for_each_possible_cpu(cpu) {
3814 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3816 if (!c || c->node < 0)
3820 if (flags & SO_TOTAL)
3821 x = c->page->objects;
3822 else if (flags & SO_OBJECTS)
3828 nodes[c->node] += x;
3834 if (flags & SO_ALL) {
3835 for_each_node_state(node, N_NORMAL_MEMORY) {
3836 struct kmem_cache_node *n = get_node(s, node);
3838 if (flags & SO_TOTAL)
3839 x = atomic_long_read(&n->total_objects);
3840 else if (flags & SO_OBJECTS)
3841 x = atomic_long_read(&n->total_objects) -
3842 count_partial(n, count_free);
3845 x = atomic_long_read(&n->nr_slabs);
3850 } else if (flags & SO_PARTIAL) {
3851 for_each_node_state(node, N_NORMAL_MEMORY) {
3852 struct kmem_cache_node *n = get_node(s, node);
3854 if (flags & SO_TOTAL)
3855 x = count_partial(n, count_total);
3856 else if (flags & SO_OBJECTS)
3857 x = count_partial(n, count_inuse);
3864 x = sprintf(buf, "%lu", total);
3866 for_each_node_state(node, N_NORMAL_MEMORY)
3868 x += sprintf(buf + x, " N%d=%lu",
3872 return x + sprintf(buf + x, "\n");
3875 static int any_slab_objects(struct kmem_cache *s)
3879 for_each_online_node(node) {
3880 struct kmem_cache_node *n = get_node(s, node);
3885 if (atomic_long_read(&n->total_objects))
3891 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3892 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3894 struct slab_attribute {
3895 struct attribute attr;
3896 ssize_t (*show)(struct kmem_cache *s, char *buf);
3897 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
3900 #define SLAB_ATTR_RO(_name) \
3901 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3903 #define SLAB_ATTR(_name) \
3904 static struct slab_attribute _name##_attr = \
3905 __ATTR(_name, 0644, _name##_show, _name##_store)
3907 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
3909 return sprintf(buf, "%d\n", s->size);
3911 SLAB_ATTR_RO(slab_size);
3913 static ssize_t align_show(struct kmem_cache *s, char *buf)
3915 return sprintf(buf, "%d\n", s->align);
3917 SLAB_ATTR_RO(align);
3919 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
3921 return sprintf(buf, "%d\n", s->objsize);
3923 SLAB_ATTR_RO(object_size);
3925 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
3927 return sprintf(buf, "%d\n", oo_objects(s->oo));
3929 SLAB_ATTR_RO(objs_per_slab);
3931 static ssize_t order_store(struct kmem_cache *s,
3932 const char *buf, size_t length)
3934 unsigned long order;
3937 err = strict_strtoul(buf, 10, &order);
3941 if (order > slub_max_order || order < slub_min_order)
3944 calculate_sizes(s, order);
3948 static ssize_t order_show(struct kmem_cache *s, char *buf)
3950 return sprintf(buf, "%d\n", oo_order(s->oo));
3954 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
3956 return sprintf(buf, "%lu\n", s->min_partial);
3959 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
3965 err = strict_strtoul(buf, 10, &min);
3969 set_min_partial(s, min);
3972 SLAB_ATTR(min_partial);
3974 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
3977 int n = sprint_symbol(buf, (unsigned long)s->ctor);
3979 return n + sprintf(buf + n, "\n");
3985 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
3987 return sprintf(buf, "%d\n", s->refcount - 1);
3989 SLAB_ATTR_RO(aliases);
3991 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
3993 return show_slab_objects(s, buf, SO_ALL);
3995 SLAB_ATTR_RO(slabs);
3997 static ssize_t partial_show(struct kmem_cache *s, char *buf)
3999 return show_slab_objects(s, buf, SO_PARTIAL);
4001 SLAB_ATTR_RO(partial);
4003 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4005 return show_slab_objects(s, buf, SO_CPU);
4007 SLAB_ATTR_RO(cpu_slabs);
4009 static ssize_t objects_show(struct kmem_cache *s, char *buf)
4011 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4013 SLAB_ATTR_RO(objects);
4015 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4017 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4019 SLAB_ATTR_RO(objects_partial);
4021 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4023 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4025 SLAB_ATTR_RO(total_objects);
4027 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4029 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4032 static ssize_t sanity_checks_store(struct kmem_cache *s,
4033 const char *buf, size_t length)
4035 s->flags &= ~SLAB_DEBUG_FREE;
4037 s->flags |= SLAB_DEBUG_FREE;
4040 SLAB_ATTR(sanity_checks);
4042 static ssize_t trace_show(struct kmem_cache *s, char *buf)
4044 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4047 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4050 s->flags &= ~SLAB_TRACE;
4052 s->flags |= SLAB_TRACE;
4057 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4059 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4062 static ssize_t reclaim_account_store(struct kmem_cache *s,
4063 const char *buf, size_t length)
4065 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4067 s->flags |= SLAB_RECLAIM_ACCOUNT;
4070 SLAB_ATTR(reclaim_account);
4072 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4074 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4076 SLAB_ATTR_RO(hwcache_align);
4078 #ifdef CONFIG_ZONE_DMA
4079 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4081 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4083 SLAB_ATTR_RO(cache_dma);
4086 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4088 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4090 SLAB_ATTR_RO(destroy_by_rcu);
4092 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4094 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4097 static ssize_t red_zone_store(struct kmem_cache *s,
4098 const char *buf, size_t length)
4100 if (any_slab_objects(s))
4103 s->flags &= ~SLAB_RED_ZONE;
4105 s->flags |= SLAB_RED_ZONE;
4106 calculate_sizes(s, -1);
4109 SLAB_ATTR(red_zone);
4111 static ssize_t poison_show(struct kmem_cache *s, char *buf)
4113 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4116 static ssize_t poison_store(struct kmem_cache *s,
4117 const char *buf, size_t length)
4119 if (any_slab_objects(s))
4122 s->flags &= ~SLAB_POISON;
4124 s->flags |= SLAB_POISON;
4125 calculate_sizes(s, -1);
4130 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4132 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4135 static ssize_t store_user_store(struct kmem_cache *s,
4136 const char *buf, size_t length)
4138 if (any_slab_objects(s))
4141 s->flags &= ~SLAB_STORE_USER;
4143 s->flags |= SLAB_STORE_USER;
4144 calculate_sizes(s, -1);
4147 SLAB_ATTR(store_user);
4149 static ssize_t validate_show(struct kmem_cache *s, char *buf)
4154 static ssize_t validate_store(struct kmem_cache *s,
4155 const char *buf, size_t length)
4159 if (buf[0] == '1') {
4160 ret = validate_slab_cache(s);
4166 SLAB_ATTR(validate);
4168 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4173 static ssize_t shrink_store(struct kmem_cache *s,
4174 const char *buf, size_t length)
4176 if (buf[0] == '1') {
4177 int rc = kmem_cache_shrink(s);
4187 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4189 if (!(s->flags & SLAB_STORE_USER))
4191 return list_locations(s, buf, TRACK_ALLOC);
4193 SLAB_ATTR_RO(alloc_calls);
4195 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4197 if (!(s->flags & SLAB_STORE_USER))
4199 return list_locations(s, buf, TRACK_FREE);
4201 SLAB_ATTR_RO(free_calls);
4204 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4206 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4209 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4210 const char *buf, size_t length)
4212 unsigned long ratio;
4215 err = strict_strtoul(buf, 10, &ratio);
4220 s->remote_node_defrag_ratio = ratio * 10;
4224 SLAB_ATTR(remote_node_defrag_ratio);
4227 #ifdef CONFIG_SLUB_STATS
4228 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4230 unsigned long sum = 0;
4233 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4238 for_each_online_cpu(cpu) {
4239 unsigned x = get_cpu_slab(s, cpu)->stat[si];
4245 len = sprintf(buf, "%lu", sum);
4248 for_each_online_cpu(cpu) {
4249 if (data[cpu] && len < PAGE_SIZE - 20)
4250 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4254 return len + sprintf(buf + len, "\n");
4257 #define STAT_ATTR(si, text) \
4258 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4260 return show_stat(s, buf, si); \
4262 SLAB_ATTR_RO(text); \
4264 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4265 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4266 STAT_ATTR(FREE_FASTPATH, free_fastpath);
4267 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4268 STAT_ATTR(FREE_FROZEN, free_frozen);
4269 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4270 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4271 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4272 STAT_ATTR(ALLOC_SLAB, alloc_slab);
4273 STAT_ATTR(ALLOC_REFILL, alloc_refill);
4274 STAT_ATTR(FREE_SLAB, free_slab);
4275 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4276 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4277 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4278 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4279 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4280 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4281 STAT_ATTR(ORDER_FALLBACK, order_fallback);
4284 static struct attribute *slab_attrs[] = {
4285 &slab_size_attr.attr,
4286 &object_size_attr.attr,
4287 &objs_per_slab_attr.attr,
4289 &min_partial_attr.attr,
4291 &objects_partial_attr.attr,
4292 &total_objects_attr.attr,
4295 &cpu_slabs_attr.attr,
4299 &sanity_checks_attr.attr,
4301 &hwcache_align_attr.attr,
4302 &reclaim_account_attr.attr,
4303 &destroy_by_rcu_attr.attr,
4304 &red_zone_attr.attr,
4306 &store_user_attr.attr,
4307 &validate_attr.attr,
4309 &alloc_calls_attr.attr,
4310 &free_calls_attr.attr,
4311 #ifdef CONFIG_ZONE_DMA
4312 &cache_dma_attr.attr,
4315 &remote_node_defrag_ratio_attr.attr,
4317 #ifdef CONFIG_SLUB_STATS
4318 &alloc_fastpath_attr.attr,
4319 &alloc_slowpath_attr.attr,
4320 &free_fastpath_attr.attr,
4321 &free_slowpath_attr.attr,
4322 &free_frozen_attr.attr,
4323 &free_add_partial_attr.attr,
4324 &free_remove_partial_attr.attr,
4325 &alloc_from_partial_attr.attr,
4326 &alloc_slab_attr.attr,
4327 &alloc_refill_attr.attr,
4328 &free_slab_attr.attr,
4329 &cpuslab_flush_attr.attr,
4330 &deactivate_full_attr.attr,
4331 &deactivate_empty_attr.attr,
4332 &deactivate_to_head_attr.attr,
4333 &deactivate_to_tail_attr.attr,
4334 &deactivate_remote_frees_attr.attr,
4335 &order_fallback_attr.attr,
4340 static struct attribute_group slab_attr_group = {
4341 .attrs = slab_attrs,
4344 static ssize_t slab_attr_show(struct kobject *kobj,
4345 struct attribute *attr,
4348 struct slab_attribute *attribute;
4349 struct kmem_cache *s;
4352 attribute = to_slab_attr(attr);
4355 if (!attribute->show)
4358 err = attribute->show(s, buf);
4363 static ssize_t slab_attr_store(struct kobject *kobj,
4364 struct attribute *attr,
4365 const char *buf, size_t len)
4367 struct slab_attribute *attribute;
4368 struct kmem_cache *s;
4371 attribute = to_slab_attr(attr);
4374 if (!attribute->store)
4377 err = attribute->store(s, buf, len);
4382 static void kmem_cache_release(struct kobject *kobj)
4384 struct kmem_cache *s = to_slab(kobj);
4389 static struct sysfs_ops slab_sysfs_ops = {
4390 .show = slab_attr_show,
4391 .store = slab_attr_store,
4394 static struct kobj_type slab_ktype = {
4395 .sysfs_ops = &slab_sysfs_ops,
4396 .release = kmem_cache_release
4399 static int uevent_filter(struct kset *kset, struct kobject *kobj)
4401 struct kobj_type *ktype = get_ktype(kobj);
4403 if (ktype == &slab_ktype)
4408 static struct kset_uevent_ops slab_uevent_ops = {
4409 .filter = uevent_filter,
4412 static struct kset *slab_kset;
4414 #define ID_STR_LENGTH 64
4416 /* Create a unique string id for a slab cache:
4418 * Format :[flags-]size
4420 static char *create_unique_id(struct kmem_cache *s)
4422 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
4429 * First flags affecting slabcache operations. We will only
4430 * get here for aliasable slabs so we do not need to support
4431 * too many flags. The flags here must cover all flags that
4432 * are matched during merging to guarantee that the id is
4435 if (s->flags & SLAB_CACHE_DMA)
4437 if (s->flags & SLAB_RECLAIM_ACCOUNT)
4439 if (s->flags & SLAB_DEBUG_FREE)
4443 p += sprintf(p, "%07d", s->size);
4444 BUG_ON(p > name + ID_STR_LENGTH - 1);
4448 static int sysfs_slab_add(struct kmem_cache *s)
4454 if (slab_state < SYSFS)
4455 /* Defer until later */
4458 unmergeable = slab_unmergeable(s);
4461 * Slabcache can never be merged so we can use the name proper.
4462 * This is typically the case for debug situations. In that
4463 * case we can catch duplicate names easily.
4465 sysfs_remove_link(&slab_kset->kobj, s->name);
4469 * Create a unique name for the slab as a target
4472 name = create_unique_id(s);
4475 s->kobj.kset = slab_kset;
4476 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
4478 kobject_put(&s->kobj);
4482 err = sysfs_create_group(&s->kobj, &slab_attr_group);
4485 kobject_uevent(&s->kobj, KOBJ_ADD);
4487 /* Setup first alias */
4488 sysfs_slab_alias(s, s->name);
4494 static void sysfs_slab_remove(struct kmem_cache *s)
4496 kobject_uevent(&s->kobj, KOBJ_REMOVE);
4497 kobject_del(&s->kobj);
4498 kobject_put(&s->kobj);
4502 * Need to buffer aliases during bootup until sysfs becomes
4503 * available lest we lose that information.
4505 struct saved_alias {
4506 struct kmem_cache *s;
4508 struct saved_alias *next;
4511 static struct saved_alias *alias_list;
4513 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
4515 struct saved_alias *al;
4517 if (slab_state == SYSFS) {
4519 * If we have a leftover link then remove it.
4521 sysfs_remove_link(&slab_kset->kobj, name);
4522 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
4525 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
4531 al->next = alias_list;
4536 static int __init slab_sysfs_init(void)
4538 struct kmem_cache *s;
4541 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
4543 printk(KERN_ERR "Cannot register slab subsystem.\n");
4549 list_for_each_entry(s, &slab_caches, list) {
4550 err = sysfs_slab_add(s);
4552 printk(KERN_ERR "SLUB: Unable to add boot slab %s"
4553 " to sysfs\n", s->name);
4556 while (alias_list) {
4557 struct saved_alias *al = alias_list;
4559 alias_list = alias_list->next;
4560 err = sysfs_slab_alias(al->s, al->name);
4562 printk(KERN_ERR "SLUB: Unable to add boot slab alias"
4563 " %s to sysfs\n", s->name);
4571 __initcall(slab_sysfs_init);
4575 * The /proc/slabinfo ABI
4577 #ifdef CONFIG_SLABINFO
4578 static void print_slabinfo_header(struct seq_file *m)
4580 seq_puts(m, "slabinfo - version: 2.1\n");
4581 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
4582 "<objperslab> <pagesperslab>");
4583 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
4584 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4588 static void *s_start(struct seq_file *m, loff_t *pos)
4592 down_read(&slub_lock);
4594 print_slabinfo_header(m);
4596 return seq_list_start(&slab_caches, *pos);
4599 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4601 return seq_list_next(p, &slab_caches, pos);
4604 static void s_stop(struct seq_file *m, void *p)
4606 up_read(&slub_lock);
4609 static int s_show(struct seq_file *m, void *p)
4611 unsigned long nr_partials = 0;
4612 unsigned long nr_slabs = 0;
4613 unsigned long nr_inuse = 0;
4614 unsigned long nr_objs = 0;
4615 unsigned long nr_free = 0;
4616 struct kmem_cache *s;
4619 s = list_entry(p, struct kmem_cache, list);
4621 for_each_online_node(node) {
4622 struct kmem_cache_node *n = get_node(s, node);
4627 nr_partials += n->nr_partial;
4628 nr_slabs += atomic_long_read(&n->nr_slabs);
4629 nr_objs += atomic_long_read(&n->total_objects);
4630 nr_free += count_partial(n, count_free);
4633 nr_inuse = nr_objs - nr_free;
4635 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
4636 nr_objs, s->size, oo_objects(s->oo),
4637 (1 << oo_order(s->oo)));
4638 seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
4639 seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
4645 static const struct seq_operations slabinfo_op = {
4652 static int slabinfo_open(struct inode *inode, struct file *file)
4654 return seq_open(file, &slabinfo_op);
4657 static const struct file_operations proc_slabinfo_operations = {
4658 .open = slabinfo_open,
4660 .llseek = seq_lseek,
4661 .release = seq_release,
4664 static int __init slab_proc_init(void)
4666 proc_create("slabinfo",S_IWUSR|S_IRUGO,NULL,&proc_slabinfo_operations);
4669 module_init(slab_proc_init);
4670 #endif /* CONFIG_SLABINFO */