2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
5 * The allocator synchronizes using per slab locks or atomic operatios
6 * and only uses a centralized lock to manage a pool of partial slabs.
8 * (C) 2007 SGI, Christoph Lameter
9 * (C) 2011 Linux Foundation, Christoph Lameter
13 #include <linux/swap.h> /* struct reclaim_state */
14 #include <linux/module.h>
15 #include <linux/bit_spinlock.h>
16 #include <linux/interrupt.h>
17 #include <linux/bitops.h>
18 #include <linux/slab.h>
20 #include <linux/proc_fs.h>
21 #include <linux/seq_file.h>
22 #include <linux/kmemcheck.h>
23 #include <linux/cpu.h>
24 #include <linux/cpuset.h>
25 #include <linux/mempolicy.h>
26 #include <linux/ctype.h>
27 #include <linux/debugobjects.h>
28 #include <linux/kallsyms.h>
29 #include <linux/memory.h>
30 #include <linux/math64.h>
31 #include <linux/fault-inject.h>
32 #include <linux/stacktrace.h>
33 #include <linux/prefetch.h>
34 #include <linux/memcontrol.h>
36 #include <trace/events/kmem.h>
42 * 1. slab_mutex (Global Mutex)
44 * 3. slab_lock(page) (Only on some arches and for debugging)
48 * The role of the slab_mutex is to protect the list of all the slabs
49 * and to synchronize major metadata changes to slab cache structures.
51 * The slab_lock is only used for debugging and on arches that do not
52 * have the ability to do a cmpxchg_double. It only protects the second
53 * double word in the page struct. Meaning
54 * A. page->freelist -> List of object free in a page
55 * B. page->counters -> Counters of objects
56 * C. page->frozen -> frozen state
58 * If a slab is frozen then it is exempt from list management. It is not
59 * on any list. The processor that froze the slab is the one who can
60 * perform list operations on the page. Other processors may put objects
61 * onto the freelist but the processor that froze the slab is the only
62 * one that can retrieve the objects from the page's freelist.
64 * The list_lock protects the partial and full list on each node and
65 * the partial slab counter. If taken then no new slabs may be added or
66 * removed from the lists nor make the number of partial slabs be modified.
67 * (Note that the total number of slabs is an atomic value that may be
68 * modified without taking the list lock).
70 * The list_lock is a centralized lock and thus we avoid taking it as
71 * much as possible. As long as SLUB does not have to handle partial
72 * slabs, operations can continue without any centralized lock. F.e.
73 * allocating a long series of objects that fill up slabs does not require
75 * Interrupts are disabled during allocation and deallocation in order to
76 * make the slab allocator safe to use in the context of an irq. In addition
77 * interrupts are disabled to ensure that the processor does not change
78 * while handling per_cpu slabs, due to kernel preemption.
80 * SLUB assigns one slab for allocation to each processor.
81 * Allocations only occur from these slabs called cpu slabs.
83 * Slabs with free elements are kept on a partial list and during regular
84 * operations no list for full slabs is used. If an object in a full slab is
85 * freed then the slab will show up again on the partial lists.
86 * We track full slabs for debugging purposes though because otherwise we
87 * cannot scan all objects.
89 * Slabs are freed when they become empty. Teardown and setup is
90 * minimal so we rely on the page allocators per cpu caches for
91 * fast frees and allocs.
93 * Overloading of page flags that are otherwise used for LRU management.
95 * PageActive The slab is frozen and exempt from list processing.
96 * This means that the slab is dedicated to a purpose
97 * such as satisfying allocations for a specific
98 * processor. Objects may be freed in the slab while
99 * it is frozen but slab_free will then skip the usual
100 * list operations. It is up to the processor holding
101 * the slab to integrate the slab into the slab lists
102 * when the slab is no longer needed.
104 * One use of this flag is to mark slabs that are
105 * used for allocations. Then such a slab becomes a cpu
106 * slab. The cpu slab may be equipped with an additional
107 * freelist that allows lockless access to
108 * free objects in addition to the regular freelist
109 * that requires the slab lock.
111 * PageError Slab requires special handling due to debug
112 * options set. This moves slab handling out of
113 * the fast path and disables lockless freelists.
116 static inline int kmem_cache_debug(struct kmem_cache *s)
118 #ifdef CONFIG_SLUB_DEBUG
119 return unlikely(s->flags & SLAB_DEBUG_FLAGS);
126 * Issues still to be resolved:
128 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
130 * - Variable sizing of the per node arrays
133 /* Enable to test recovery from slab corruption on boot */
134 #undef SLUB_RESILIENCY_TEST
136 /* Enable to log cmpxchg failures */
137 #undef SLUB_DEBUG_CMPXCHG
140 * Mininum number of partial slabs. These will be left on the partial
141 * lists even if they are empty. kmem_cache_shrink may reclaim them.
143 #define MIN_PARTIAL 5
146 * Maximum number of desirable partial slabs.
147 * The existence of more partial slabs makes kmem_cache_shrink
148 * sort the partial list by the number of objects in the.
150 #define MAX_PARTIAL 10
152 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
153 SLAB_POISON | SLAB_STORE_USER)
156 * Debugging flags that require metadata to be stored in the slab. These get
157 * disabled when slub_debug=O is used and a cache's min order increases with
160 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
163 * Set of flags that will prevent slab merging
165 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
166 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
169 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
170 SLAB_CACHE_DMA | SLAB_NOTRACK)
173 #define OO_MASK ((1 << OO_SHIFT) - 1)
174 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
176 /* Internal SLUB flags */
177 #define __OBJECT_POISON 0x80000000UL /* Poison object */
178 #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
181 static struct notifier_block slab_notifier;
185 * Tracking user of a slab.
187 #define TRACK_ADDRS_COUNT 16
189 unsigned long addr; /* Called from address */
190 #ifdef CONFIG_STACKTRACE
191 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
193 int cpu; /* Was running on cpu */
194 int pid; /* Pid context */
195 unsigned long when; /* When did the operation occur */
198 enum track_item { TRACK_ALLOC, TRACK_FREE };
201 static int sysfs_slab_add(struct kmem_cache *);
202 static int sysfs_slab_alias(struct kmem_cache *, const char *);
203 static void sysfs_slab_remove(struct kmem_cache *);
204 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
206 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
207 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
209 static inline void sysfs_slab_remove(struct kmem_cache *s) { }
211 static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
214 static inline void stat(const struct kmem_cache *s, enum stat_item si)
216 #ifdef CONFIG_SLUB_STATS
217 __this_cpu_inc(s->cpu_slab->stat[si]);
221 /********************************************************************
222 * Core slab cache functions
223 *******************************************************************/
225 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
227 return s->node[node];
230 /* Verify that a pointer has an address that is valid within a slab page */
231 static inline int check_valid_pointer(struct kmem_cache *s,
232 struct page *page, const void *object)
239 base = page_address(page);
240 if (object < base || object >= base + page->objects * s->size ||
241 (object - base) % s->size) {
248 static inline void *get_freepointer(struct kmem_cache *s, void *object)
250 return *(void **)(object + s->offset);
253 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
255 prefetch(object + s->offset);
258 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
262 #ifdef CONFIG_DEBUG_PAGEALLOC
263 probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
265 p = get_freepointer(s, object);
270 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
272 *(void **)(object + s->offset) = fp;
275 /* Loop over all objects in a slab */
276 #define for_each_object(__p, __s, __addr, __objects) \
277 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
280 /* Determine object index from a given position */
281 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
283 return (p - addr) / s->size;
286 static inline size_t slab_ksize(const struct kmem_cache *s)
288 #ifdef CONFIG_SLUB_DEBUG
290 * Debugging requires use of the padding between object
291 * and whatever may come after it.
293 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
294 return s->object_size;
298 * If we have the need to store the freelist pointer
299 * back there or track user information then we can
300 * only use the space before that information.
302 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
305 * Else we can use all the padding etc for the allocation
310 static inline int order_objects(int order, unsigned long size, int reserved)
312 return ((PAGE_SIZE << order) - reserved) / size;
315 static inline struct kmem_cache_order_objects oo_make(int order,
316 unsigned long size, int reserved)
318 struct kmem_cache_order_objects x = {
319 (order << OO_SHIFT) + order_objects(order, size, reserved)
325 static inline int oo_order(struct kmem_cache_order_objects x)
327 return x.x >> OO_SHIFT;
330 static inline int oo_objects(struct kmem_cache_order_objects x)
332 return x.x & OO_MASK;
336 * Per slab locking using the pagelock
338 static __always_inline void slab_lock(struct page *page)
340 bit_spin_lock(PG_locked, &page->flags);
343 static __always_inline void slab_unlock(struct page *page)
345 __bit_spin_unlock(PG_locked, &page->flags);
348 /* Interrupts must be disabled (for the fallback code to work right) */
349 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
350 void *freelist_old, unsigned long counters_old,
351 void *freelist_new, unsigned long counters_new,
354 VM_BUG_ON(!irqs_disabled());
355 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
356 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
357 if (s->flags & __CMPXCHG_DOUBLE) {
358 if (cmpxchg_double(&page->freelist, &page->counters,
359 freelist_old, counters_old,
360 freelist_new, counters_new))
366 if (page->freelist == freelist_old && page->counters == counters_old) {
367 page->freelist = freelist_new;
368 page->counters = counters_new;
376 stat(s, CMPXCHG_DOUBLE_FAIL);
378 #ifdef SLUB_DEBUG_CMPXCHG
379 printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
385 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
386 void *freelist_old, unsigned long counters_old,
387 void *freelist_new, unsigned long counters_new,
390 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
391 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
392 if (s->flags & __CMPXCHG_DOUBLE) {
393 if (cmpxchg_double(&page->freelist, &page->counters,
394 freelist_old, counters_old,
395 freelist_new, counters_new))
402 local_irq_save(flags);
404 if (page->freelist == freelist_old && page->counters == counters_old) {
405 page->freelist = freelist_new;
406 page->counters = counters_new;
408 local_irq_restore(flags);
412 local_irq_restore(flags);
416 stat(s, CMPXCHG_DOUBLE_FAIL);
418 #ifdef SLUB_DEBUG_CMPXCHG
419 printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
425 #ifdef CONFIG_SLUB_DEBUG
427 * Determine a map of object in use on a page.
429 * Node listlock must be held to guarantee that the page does
430 * not vanish from under us.
432 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
435 void *addr = page_address(page);
437 for (p = page->freelist; p; p = get_freepointer(s, p))
438 set_bit(slab_index(p, s, addr), map);
444 #ifdef CONFIG_SLUB_DEBUG_ON
445 static int slub_debug = DEBUG_DEFAULT_FLAGS;
447 static int slub_debug;
450 static char *slub_debug_slabs;
451 static int disable_higher_order_debug;
456 static void print_section(char *text, u8 *addr, unsigned int length)
458 print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
462 static struct track *get_track(struct kmem_cache *s, void *object,
463 enum track_item alloc)
468 p = object + s->offset + sizeof(void *);
470 p = object + s->inuse;
475 static void set_track(struct kmem_cache *s, void *object,
476 enum track_item alloc, unsigned long addr)
478 struct track *p = get_track(s, object, alloc);
481 #ifdef CONFIG_STACKTRACE
482 struct stack_trace trace;
485 trace.nr_entries = 0;
486 trace.max_entries = TRACK_ADDRS_COUNT;
487 trace.entries = p->addrs;
489 save_stack_trace(&trace);
491 /* See rant in lockdep.c */
492 if (trace.nr_entries != 0 &&
493 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
496 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
500 p->cpu = smp_processor_id();
501 p->pid = current->pid;
504 memset(p, 0, sizeof(struct track));
507 static void init_tracking(struct kmem_cache *s, void *object)
509 if (!(s->flags & SLAB_STORE_USER))
512 set_track(s, object, TRACK_FREE, 0UL);
513 set_track(s, object, TRACK_ALLOC, 0UL);
516 static void print_track(const char *s, struct track *t)
521 printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
522 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
523 #ifdef CONFIG_STACKTRACE
526 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
528 printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
535 static void print_tracking(struct kmem_cache *s, void *object)
537 if (!(s->flags & SLAB_STORE_USER))
540 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
541 print_track("Freed", get_track(s, object, TRACK_FREE));
544 static void print_page_info(struct page *page)
546 printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
547 page, page->objects, page->inuse, page->freelist, page->flags);
551 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
557 vsnprintf(buf, sizeof(buf), fmt, args);
559 printk(KERN_ERR "========================================"
560 "=====================================\n");
561 printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
562 printk(KERN_ERR "----------------------------------------"
563 "-------------------------------------\n\n");
565 add_taint(TAINT_BAD_PAGE);
568 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
574 vsnprintf(buf, sizeof(buf), fmt, args);
576 printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
579 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
581 unsigned int off; /* Offset of last byte */
582 u8 *addr = page_address(page);
584 print_tracking(s, p);
586 print_page_info(page);
588 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
589 p, p - addr, get_freepointer(s, p));
592 print_section("Bytes b4 ", p - 16, 16);
594 print_section("Object ", p, min_t(unsigned long, s->object_size,
596 if (s->flags & SLAB_RED_ZONE)
597 print_section("Redzone ", p + s->object_size,
598 s->inuse - s->object_size);
601 off = s->offset + sizeof(void *);
605 if (s->flags & SLAB_STORE_USER)
606 off += 2 * sizeof(struct track);
609 /* Beginning of the filler is the free pointer */
610 print_section("Padding ", p + off, s->size - off);
615 static void object_err(struct kmem_cache *s, struct page *page,
616 u8 *object, char *reason)
618 slab_bug(s, "%s", reason);
619 print_trailer(s, page, object);
622 static void slab_err(struct kmem_cache *s, struct page *page, const char *fmt, ...)
628 vsnprintf(buf, sizeof(buf), fmt, args);
630 slab_bug(s, "%s", buf);
631 print_page_info(page);
635 static void init_object(struct kmem_cache *s, void *object, u8 val)
639 if (s->flags & __OBJECT_POISON) {
640 memset(p, POISON_FREE, s->object_size - 1);
641 p[s->object_size - 1] = POISON_END;
644 if (s->flags & SLAB_RED_ZONE)
645 memset(p + s->object_size, val, s->inuse - s->object_size);
648 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
649 void *from, void *to)
651 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
652 memset(from, data, to - from);
655 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
656 u8 *object, char *what,
657 u8 *start, unsigned int value, unsigned int bytes)
662 fault = memchr_inv(start, value, bytes);
667 while (end > fault && end[-1] == value)
670 slab_bug(s, "%s overwritten", what);
671 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
672 fault, end - 1, fault[0], value);
673 print_trailer(s, page, object);
675 restore_bytes(s, what, value, fault, end);
683 * Bytes of the object to be managed.
684 * If the freepointer may overlay the object then the free
685 * pointer is the first word of the object.
687 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
690 * object + s->object_size
691 * Padding to reach word boundary. This is also used for Redzoning.
692 * Padding is extended by another word if Redzoning is enabled and
693 * object_size == inuse.
695 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
696 * 0xcc (RED_ACTIVE) for objects in use.
699 * Meta data starts here.
701 * A. Free pointer (if we cannot overwrite object on free)
702 * B. Tracking data for SLAB_STORE_USER
703 * C. Padding to reach required alignment boundary or at mininum
704 * one word if debugging is on to be able to detect writes
705 * before the word boundary.
707 * Padding is done using 0x5a (POISON_INUSE)
710 * Nothing is used beyond s->size.
712 * If slabcaches are merged then the object_size and inuse boundaries are mostly
713 * ignored. And therefore no slab options that rely on these boundaries
714 * may be used with merged slabcaches.
717 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
719 unsigned long off = s->inuse; /* The end of info */
722 /* Freepointer is placed after the object. */
723 off += sizeof(void *);
725 if (s->flags & SLAB_STORE_USER)
726 /* We also have user information there */
727 off += 2 * sizeof(struct track);
732 return check_bytes_and_report(s, page, p, "Object padding",
733 p + off, POISON_INUSE, s->size - off);
736 /* Check the pad bytes at the end of a slab page */
737 static int slab_pad_check(struct kmem_cache *s, struct page *page)
745 if (!(s->flags & SLAB_POISON))
748 start = page_address(page);
749 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
750 end = start + length;
751 remainder = length % s->size;
755 fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
758 while (end > fault && end[-1] == POISON_INUSE)
761 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
762 print_section("Padding ", end - remainder, remainder);
764 restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
768 static int check_object(struct kmem_cache *s, struct page *page,
769 void *object, u8 val)
772 u8 *endobject = object + s->object_size;
774 if (s->flags & SLAB_RED_ZONE) {
775 if (!check_bytes_and_report(s, page, object, "Redzone",
776 endobject, val, s->inuse - s->object_size))
779 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
780 check_bytes_and_report(s, page, p, "Alignment padding",
781 endobject, POISON_INUSE, s->inuse - s->object_size);
785 if (s->flags & SLAB_POISON) {
786 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
787 (!check_bytes_and_report(s, page, p, "Poison", p,
788 POISON_FREE, s->object_size - 1) ||
789 !check_bytes_and_report(s, page, p, "Poison",
790 p + s->object_size - 1, POISON_END, 1)))
793 * check_pad_bytes cleans up on its own.
795 check_pad_bytes(s, page, p);
798 if (!s->offset && val == SLUB_RED_ACTIVE)
800 * Object and freepointer overlap. Cannot check
801 * freepointer while object is allocated.
805 /* Check free pointer validity */
806 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
807 object_err(s, page, p, "Freepointer corrupt");
809 * No choice but to zap it and thus lose the remainder
810 * of the free objects in this slab. May cause
811 * another error because the object count is now wrong.
813 set_freepointer(s, p, NULL);
819 static int check_slab(struct kmem_cache *s, struct page *page)
823 VM_BUG_ON(!irqs_disabled());
825 if (!PageSlab(page)) {
826 slab_err(s, page, "Not a valid slab page");
830 maxobj = order_objects(compound_order(page), s->size, s->reserved);
831 if (page->objects > maxobj) {
832 slab_err(s, page, "objects %u > max %u",
833 s->name, page->objects, maxobj);
836 if (page->inuse > page->objects) {
837 slab_err(s, page, "inuse %u > max %u",
838 s->name, page->inuse, page->objects);
841 /* Slab_pad_check fixes things up after itself */
842 slab_pad_check(s, page);
847 * Determine if a certain object on a page is on the freelist. Must hold the
848 * slab lock to guarantee that the chains are in a consistent state.
850 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
855 unsigned long max_objects;
858 while (fp && nr <= page->objects) {
861 if (!check_valid_pointer(s, page, fp)) {
863 object_err(s, page, object,
864 "Freechain corrupt");
865 set_freepointer(s, object, NULL);
868 slab_err(s, page, "Freepointer corrupt");
869 page->freelist = NULL;
870 page->inuse = page->objects;
871 slab_fix(s, "Freelist cleared");
877 fp = get_freepointer(s, object);
881 max_objects = order_objects(compound_order(page), s->size, s->reserved);
882 if (max_objects > MAX_OBJS_PER_PAGE)
883 max_objects = MAX_OBJS_PER_PAGE;
885 if (page->objects != max_objects) {
886 slab_err(s, page, "Wrong number of objects. Found %d but "
887 "should be %d", page->objects, max_objects);
888 page->objects = max_objects;
889 slab_fix(s, "Number of objects adjusted.");
891 if (page->inuse != page->objects - nr) {
892 slab_err(s, page, "Wrong object count. Counter is %d but "
893 "counted were %d", page->inuse, page->objects - nr);
894 page->inuse = page->objects - nr;
895 slab_fix(s, "Object count adjusted.");
897 return search == NULL;
900 static void trace(struct kmem_cache *s, struct page *page, void *object,
903 if (s->flags & SLAB_TRACE) {
904 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
906 alloc ? "alloc" : "free",
911 print_section("Object ", (void *)object, s->object_size);
918 * Hooks for other subsystems that check memory allocations. In a typical
919 * production configuration these hooks all should produce no code at all.
921 static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
923 flags &= gfp_allowed_mask;
924 lockdep_trace_alloc(flags);
925 might_sleep_if(flags & __GFP_WAIT);
927 return should_failslab(s->object_size, flags, s->flags);
930 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
932 flags &= gfp_allowed_mask;
933 kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
934 kmemleak_alloc_recursive(object, s->object_size, 1, s->flags, flags);
937 static inline void slab_free_hook(struct kmem_cache *s, void *x)
939 kmemleak_free_recursive(x, s->flags);
942 * Trouble is that we may no longer disable interupts in the fast path
943 * So in order to make the debug calls that expect irqs to be
944 * disabled we need to disable interrupts temporarily.
946 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
950 local_irq_save(flags);
951 kmemcheck_slab_free(s, x, s->object_size);
952 debug_check_no_locks_freed(x, s->object_size);
953 local_irq_restore(flags);
956 if (!(s->flags & SLAB_DEBUG_OBJECTS))
957 debug_check_no_obj_freed(x, s->object_size);
961 * Tracking of fully allocated slabs for debugging purposes.
963 * list_lock must be held.
965 static void add_full(struct kmem_cache *s,
966 struct kmem_cache_node *n, struct page *page)
968 if (!(s->flags & SLAB_STORE_USER))
971 list_add(&page->lru, &n->full);
975 * list_lock must be held.
977 static void remove_full(struct kmem_cache *s, struct page *page)
979 if (!(s->flags & SLAB_STORE_USER))
982 list_del(&page->lru);
985 /* Tracking of the number of slabs for debugging purposes */
986 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
988 struct kmem_cache_node *n = get_node(s, node);
990 return atomic_long_read(&n->nr_slabs);
993 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
995 return atomic_long_read(&n->nr_slabs);
998 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1000 struct kmem_cache_node *n = get_node(s, node);
1003 * May be called early in order to allocate a slab for the
1004 * kmem_cache_node structure. Solve the chicken-egg
1005 * dilemma by deferring the increment of the count during
1006 * bootstrap (see early_kmem_cache_node_alloc).
1009 atomic_long_inc(&n->nr_slabs);
1010 atomic_long_add(objects, &n->total_objects);
1013 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1015 struct kmem_cache_node *n = get_node(s, node);
1017 atomic_long_dec(&n->nr_slabs);
1018 atomic_long_sub(objects, &n->total_objects);
1021 /* Object debug checks for alloc/free paths */
1022 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1025 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1028 init_object(s, object, SLUB_RED_INACTIVE);
1029 init_tracking(s, object);
1032 static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1033 void *object, unsigned long addr)
1035 if (!check_slab(s, page))
1038 if (!check_valid_pointer(s, page, object)) {
1039 object_err(s, page, object, "Freelist Pointer check fails");
1043 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1046 /* Success perform special debug activities for allocs */
1047 if (s->flags & SLAB_STORE_USER)
1048 set_track(s, object, TRACK_ALLOC, addr);
1049 trace(s, page, object, 1);
1050 init_object(s, object, SLUB_RED_ACTIVE);
1054 if (PageSlab(page)) {
1056 * If this is a slab page then lets do the best we can
1057 * to avoid issues in the future. Marking all objects
1058 * as used avoids touching the remaining objects.
1060 slab_fix(s, "Marking all objects used");
1061 page->inuse = page->objects;
1062 page->freelist = NULL;
1067 static noinline struct kmem_cache_node *free_debug_processing(
1068 struct kmem_cache *s, struct page *page, void *object,
1069 unsigned long addr, unsigned long *flags)
1071 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1073 spin_lock_irqsave(&n->list_lock, *flags);
1076 if (!check_slab(s, page))
1079 if (!check_valid_pointer(s, page, object)) {
1080 slab_err(s, page, "Invalid object pointer 0x%p", object);
1084 if (on_freelist(s, page, object)) {
1085 object_err(s, page, object, "Object already free");
1089 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1092 if (unlikely(s != page->slab_cache)) {
1093 if (!PageSlab(page)) {
1094 slab_err(s, page, "Attempt to free object(0x%p) "
1095 "outside of slab", object);
1096 } else if (!page->slab_cache) {
1098 "SLUB <none>: no slab for object 0x%p.\n",
1102 object_err(s, page, object,
1103 "page slab pointer corrupt.");
1107 if (s->flags & SLAB_STORE_USER)
1108 set_track(s, object, TRACK_FREE, addr);
1109 trace(s, page, object, 0);
1110 init_object(s, object, SLUB_RED_INACTIVE);
1114 * Keep node_lock to preserve integrity
1115 * until the object is actually freed
1121 spin_unlock_irqrestore(&n->list_lock, *flags);
1122 slab_fix(s, "Object at 0x%p not freed", object);
1126 static int __init setup_slub_debug(char *str)
1128 slub_debug = DEBUG_DEFAULT_FLAGS;
1129 if (*str++ != '=' || !*str)
1131 * No options specified. Switch on full debugging.
1137 * No options but restriction on slabs. This means full
1138 * debugging for slabs matching a pattern.
1142 if (tolower(*str) == 'o') {
1144 * Avoid enabling debugging on caches if its minimum order
1145 * would increase as a result.
1147 disable_higher_order_debug = 1;
1154 * Switch off all debugging measures.
1159 * Determine which debug features should be switched on
1161 for (; *str && *str != ','; str++) {
1162 switch (tolower(*str)) {
1164 slub_debug |= SLAB_DEBUG_FREE;
1167 slub_debug |= SLAB_RED_ZONE;
1170 slub_debug |= SLAB_POISON;
1173 slub_debug |= SLAB_STORE_USER;
1176 slub_debug |= SLAB_TRACE;
1179 slub_debug |= SLAB_FAILSLAB;
1182 printk(KERN_ERR "slub_debug option '%c' "
1183 "unknown. skipped\n", *str);
1189 slub_debug_slabs = str + 1;
1194 __setup("slub_debug", setup_slub_debug);
1196 static unsigned long kmem_cache_flags(unsigned long object_size,
1197 unsigned long flags, const char *name,
1198 void (*ctor)(void *))
1201 * Enable debugging if selected on the kernel commandline.
1203 if (slub_debug && (!slub_debug_slabs ||
1204 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1205 flags |= slub_debug;
1210 static inline void setup_object_debug(struct kmem_cache *s,
1211 struct page *page, void *object) {}
1213 static inline int alloc_debug_processing(struct kmem_cache *s,
1214 struct page *page, void *object, unsigned long addr) { return 0; }
1216 static inline struct kmem_cache_node *free_debug_processing(
1217 struct kmem_cache *s, struct page *page, void *object,
1218 unsigned long addr, unsigned long *flags) { return NULL; }
1220 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1222 static inline int check_object(struct kmem_cache *s, struct page *page,
1223 void *object, u8 val) { return 1; }
1224 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1225 struct page *page) {}
1226 static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1227 static inline unsigned long kmem_cache_flags(unsigned long object_size,
1228 unsigned long flags, const char *name,
1229 void (*ctor)(void *))
1233 #define slub_debug 0
1235 #define disable_higher_order_debug 0
1237 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1239 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1241 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1243 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1246 static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1249 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1252 static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
1254 #endif /* CONFIG_SLUB_DEBUG */
1257 * Slab allocation and freeing
1259 static inline struct page *alloc_slab_page(gfp_t flags, int node,
1260 struct kmem_cache_order_objects oo)
1262 int order = oo_order(oo);
1264 flags |= __GFP_NOTRACK;
1266 if (node == NUMA_NO_NODE)
1267 return alloc_pages(flags, order);
1269 return alloc_pages_exact_node(node, flags, order);
1272 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1275 struct kmem_cache_order_objects oo = s->oo;
1278 flags &= gfp_allowed_mask;
1280 if (flags & __GFP_WAIT)
1283 flags |= s->allocflags;
1286 * Let the initial higher-order allocation fail under memory pressure
1287 * so we fall-back to the minimum order allocation.
1289 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1291 page = alloc_slab_page(alloc_gfp, node, oo);
1292 if (unlikely(!page)) {
1295 * Allocation may have failed due to fragmentation.
1296 * Try a lower order alloc if possible
1298 page = alloc_slab_page(flags, node, oo);
1301 stat(s, ORDER_FALLBACK);
1304 if (kmemcheck_enabled && page
1305 && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1306 int pages = 1 << oo_order(oo);
1308 kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1311 * Objects from caches that have a constructor don't get
1312 * cleared when they're allocated, so we need to do it here.
1315 kmemcheck_mark_uninitialized_pages(page, pages);
1317 kmemcheck_mark_unallocated_pages(page, pages);
1320 if (flags & __GFP_WAIT)
1321 local_irq_disable();
1325 page->objects = oo_objects(oo);
1326 mod_zone_page_state(page_zone(page),
1327 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1328 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1334 static void setup_object(struct kmem_cache *s, struct page *page,
1337 setup_object_debug(s, page, object);
1338 if (unlikely(s->ctor))
1342 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1350 BUG_ON(flags & GFP_SLAB_BUG_MASK);
1352 page = allocate_slab(s,
1353 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1357 order = compound_order(page);
1358 inc_slabs_node(s, page_to_nid(page), page->objects);
1359 memcg_bind_pages(s, order);
1360 page->slab_cache = s;
1361 __SetPageSlab(page);
1362 if (page->pfmemalloc)
1363 SetPageSlabPfmemalloc(page);
1365 start = page_address(page);
1367 if (unlikely(s->flags & SLAB_POISON))
1368 memset(start, POISON_INUSE, PAGE_SIZE << order);
1371 for_each_object(p, s, start, page->objects) {
1372 setup_object(s, page, last);
1373 set_freepointer(s, last, p);
1376 setup_object(s, page, last);
1377 set_freepointer(s, last, NULL);
1379 page->freelist = start;
1380 page->inuse = page->objects;
1386 static void __free_slab(struct kmem_cache *s, struct page *page)
1388 int order = compound_order(page);
1389 int pages = 1 << order;
1391 if (kmem_cache_debug(s)) {
1394 slab_pad_check(s, page);
1395 for_each_object(p, s, page_address(page),
1397 check_object(s, page, p, SLUB_RED_INACTIVE);
1400 kmemcheck_free_shadow(page, compound_order(page));
1402 mod_zone_page_state(page_zone(page),
1403 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1404 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1407 __ClearPageSlabPfmemalloc(page);
1408 __ClearPageSlab(page);
1410 memcg_release_pages(s, order);
1411 reset_page_mapcount(page);
1412 if (current->reclaim_state)
1413 current->reclaim_state->reclaimed_slab += pages;
1414 __free_memcg_kmem_pages(page, order);
1417 #define need_reserve_slab_rcu \
1418 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1420 static void rcu_free_slab(struct rcu_head *h)
1424 if (need_reserve_slab_rcu)
1425 page = virt_to_head_page(h);
1427 page = container_of((struct list_head *)h, struct page, lru);
1429 __free_slab(page->slab_cache, page);
1432 static void free_slab(struct kmem_cache *s, struct page *page)
1434 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1435 struct rcu_head *head;
1437 if (need_reserve_slab_rcu) {
1438 int order = compound_order(page);
1439 int offset = (PAGE_SIZE << order) - s->reserved;
1441 VM_BUG_ON(s->reserved != sizeof(*head));
1442 head = page_address(page) + offset;
1445 * RCU free overloads the RCU head over the LRU
1447 head = (void *)&page->lru;
1450 call_rcu(head, rcu_free_slab);
1452 __free_slab(s, page);
1455 static void discard_slab(struct kmem_cache *s, struct page *page)
1457 dec_slabs_node(s, page_to_nid(page), page->objects);
1462 * Management of partially allocated slabs.
1464 * list_lock must be held.
1466 static inline void add_partial(struct kmem_cache_node *n,
1467 struct page *page, int tail)
1470 if (tail == DEACTIVATE_TO_TAIL)
1471 list_add_tail(&page->lru, &n->partial);
1473 list_add(&page->lru, &n->partial);
1477 * list_lock must be held.
1479 static inline void remove_partial(struct kmem_cache_node *n,
1482 list_del(&page->lru);
1487 * Remove slab from the partial list, freeze it and
1488 * return the pointer to the freelist.
1490 * Returns a list of objects or NULL if it fails.
1492 * Must hold list_lock since we modify the partial list.
1494 static inline void *acquire_slab(struct kmem_cache *s,
1495 struct kmem_cache_node *n, struct page *page,
1496 int mode, int *objects)
1499 unsigned long counters;
1503 * Zap the freelist and set the frozen bit.
1504 * The old freelist is the list of objects for the
1505 * per cpu allocation list.
1507 freelist = page->freelist;
1508 counters = page->counters;
1509 new.counters = counters;
1510 *objects = new.objects - new.inuse;
1512 new.inuse = page->objects;
1513 new.freelist = NULL;
1515 new.freelist = freelist;
1518 VM_BUG_ON(new.frozen);
1521 if (!__cmpxchg_double_slab(s, page,
1523 new.freelist, new.counters,
1527 remove_partial(n, page);
1532 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1533 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1536 * Try to allocate a partial slab from a specific node.
1538 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1539 struct kmem_cache_cpu *c, gfp_t flags)
1541 struct page *page, *page2;
1542 void *object = NULL;
1547 * Racy check. If we mistakenly see no partial slabs then we
1548 * just allocate an empty slab. If we mistakenly try to get a
1549 * partial slab and there is none available then get_partials()
1552 if (!n || !n->nr_partial)
1555 spin_lock(&n->list_lock);
1556 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1559 if (!pfmemalloc_match(page, flags))
1562 t = acquire_slab(s, n, page, object == NULL, &objects);
1566 available += objects;
1569 stat(s, ALLOC_FROM_PARTIAL);
1572 put_cpu_partial(s, page, 0);
1573 stat(s, CPU_PARTIAL_NODE);
1575 if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
1579 spin_unlock(&n->list_lock);
1584 * Get a page from somewhere. Search in increasing NUMA distances.
1586 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1587 struct kmem_cache_cpu *c)
1590 struct zonelist *zonelist;
1593 enum zone_type high_zoneidx = gfp_zone(flags);
1595 unsigned int cpuset_mems_cookie;
1598 * The defrag ratio allows a configuration of the tradeoffs between
1599 * inter node defragmentation and node local allocations. A lower
1600 * defrag_ratio increases the tendency to do local allocations
1601 * instead of attempting to obtain partial slabs from other nodes.
1603 * If the defrag_ratio is set to 0 then kmalloc() always
1604 * returns node local objects. If the ratio is higher then kmalloc()
1605 * may return off node objects because partial slabs are obtained
1606 * from other nodes and filled up.
1608 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1609 * defrag_ratio = 1000) then every (well almost) allocation will
1610 * first attempt to defrag slab caches on other nodes. This means
1611 * scanning over all nodes to look for partial slabs which may be
1612 * expensive if we do it every time we are trying to find a slab
1613 * with available objects.
1615 if (!s->remote_node_defrag_ratio ||
1616 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1620 cpuset_mems_cookie = get_mems_allowed();
1621 zonelist = node_zonelist(slab_node(), flags);
1622 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1623 struct kmem_cache_node *n;
1625 n = get_node(s, zone_to_nid(zone));
1627 if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1628 n->nr_partial > s->min_partial) {
1629 object = get_partial_node(s, n, c, flags);
1632 * Return the object even if
1633 * put_mems_allowed indicated that
1634 * the cpuset mems_allowed was
1635 * updated in parallel. It's a
1636 * harmless race between the alloc
1637 * and the cpuset update.
1639 put_mems_allowed(cpuset_mems_cookie);
1644 } while (!put_mems_allowed(cpuset_mems_cookie));
1650 * Get a partial page, lock it and return it.
1652 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1653 struct kmem_cache_cpu *c)
1656 int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
1658 object = get_partial_node(s, get_node(s, searchnode), c, flags);
1659 if (object || node != NUMA_NO_NODE)
1662 return get_any_partial(s, flags, c);
1665 #ifdef CONFIG_PREEMPT
1667 * Calculate the next globally unique transaction for disambiguiation
1668 * during cmpxchg. The transactions start with the cpu number and are then
1669 * incremented by CONFIG_NR_CPUS.
1671 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1674 * No preemption supported therefore also no need to check for
1680 static inline unsigned long next_tid(unsigned long tid)
1682 return tid + TID_STEP;
1685 static inline unsigned int tid_to_cpu(unsigned long tid)
1687 return tid % TID_STEP;
1690 static inline unsigned long tid_to_event(unsigned long tid)
1692 return tid / TID_STEP;
1695 static inline unsigned int init_tid(int cpu)
1700 static inline void note_cmpxchg_failure(const char *n,
1701 const struct kmem_cache *s, unsigned long tid)
1703 #ifdef SLUB_DEBUG_CMPXCHG
1704 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1706 printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1708 #ifdef CONFIG_PREEMPT
1709 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1710 printk("due to cpu change %d -> %d\n",
1711 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1714 if (tid_to_event(tid) != tid_to_event(actual_tid))
1715 printk("due to cpu running other code. Event %ld->%ld\n",
1716 tid_to_event(tid), tid_to_event(actual_tid));
1718 printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1719 actual_tid, tid, next_tid(tid));
1721 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1724 static void init_kmem_cache_cpus(struct kmem_cache *s)
1728 for_each_possible_cpu(cpu)
1729 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1733 * Remove the cpu slab
1735 static void deactivate_slab(struct kmem_cache *s, struct page *page, void *freelist)
1737 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1738 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1740 enum slab_modes l = M_NONE, m = M_NONE;
1742 int tail = DEACTIVATE_TO_HEAD;
1746 if (page->freelist) {
1747 stat(s, DEACTIVATE_REMOTE_FREES);
1748 tail = DEACTIVATE_TO_TAIL;
1752 * Stage one: Free all available per cpu objects back
1753 * to the page freelist while it is still frozen. Leave the
1756 * There is no need to take the list->lock because the page
1759 while (freelist && (nextfree = get_freepointer(s, freelist))) {
1761 unsigned long counters;
1764 prior = page->freelist;
1765 counters = page->counters;
1766 set_freepointer(s, freelist, prior);
1767 new.counters = counters;
1769 VM_BUG_ON(!new.frozen);
1771 } while (!__cmpxchg_double_slab(s, page,
1773 freelist, new.counters,
1774 "drain percpu freelist"));
1776 freelist = nextfree;
1780 * Stage two: Ensure that the page is unfrozen while the
1781 * list presence reflects the actual number of objects
1784 * We setup the list membership and then perform a cmpxchg
1785 * with the count. If there is a mismatch then the page
1786 * is not unfrozen but the page is on the wrong list.
1788 * Then we restart the process which may have to remove
1789 * the page from the list that we just put it on again
1790 * because the number of objects in the slab may have
1795 old.freelist = page->freelist;
1796 old.counters = page->counters;
1797 VM_BUG_ON(!old.frozen);
1799 /* Determine target state of the slab */
1800 new.counters = old.counters;
1803 set_freepointer(s, freelist, old.freelist);
1804 new.freelist = freelist;
1806 new.freelist = old.freelist;
1810 if (!new.inuse && n->nr_partial > s->min_partial)
1812 else if (new.freelist) {
1817 * Taking the spinlock removes the possiblity
1818 * that acquire_slab() will see a slab page that
1821 spin_lock(&n->list_lock);
1825 if (kmem_cache_debug(s) && !lock) {
1828 * This also ensures that the scanning of full
1829 * slabs from diagnostic functions will not see
1832 spin_lock(&n->list_lock);
1840 remove_partial(n, page);
1842 else if (l == M_FULL)
1844 remove_full(s, page);
1846 if (m == M_PARTIAL) {
1848 add_partial(n, page, tail);
1851 } else if (m == M_FULL) {
1853 stat(s, DEACTIVATE_FULL);
1854 add_full(s, n, page);
1860 if (!__cmpxchg_double_slab(s, page,
1861 old.freelist, old.counters,
1862 new.freelist, new.counters,
1867 spin_unlock(&n->list_lock);
1870 stat(s, DEACTIVATE_EMPTY);
1871 discard_slab(s, page);
1877 * Unfreeze all the cpu partial slabs.
1879 * This function must be called with interrupts disabled
1880 * for the cpu using c (or some other guarantee must be there
1881 * to guarantee no concurrent accesses).
1883 static void unfreeze_partials(struct kmem_cache *s,
1884 struct kmem_cache_cpu *c)
1886 struct kmem_cache_node *n = NULL, *n2 = NULL;
1887 struct page *page, *discard_page = NULL;
1889 while ((page = c->partial)) {
1893 c->partial = page->next;
1895 n2 = get_node(s, page_to_nid(page));
1898 spin_unlock(&n->list_lock);
1901 spin_lock(&n->list_lock);
1906 old.freelist = page->freelist;
1907 old.counters = page->counters;
1908 VM_BUG_ON(!old.frozen);
1910 new.counters = old.counters;
1911 new.freelist = old.freelist;
1915 } while (!__cmpxchg_double_slab(s, page,
1916 old.freelist, old.counters,
1917 new.freelist, new.counters,
1918 "unfreezing slab"));
1920 if (unlikely(!new.inuse && n->nr_partial > s->min_partial)) {
1921 page->next = discard_page;
1922 discard_page = page;
1924 add_partial(n, page, DEACTIVATE_TO_TAIL);
1925 stat(s, FREE_ADD_PARTIAL);
1930 spin_unlock(&n->list_lock);
1932 while (discard_page) {
1933 page = discard_page;
1934 discard_page = discard_page->next;
1936 stat(s, DEACTIVATE_EMPTY);
1937 discard_slab(s, page);
1943 * Put a page that was just frozen (in __slab_free) into a partial page
1944 * slot if available. This is done without interrupts disabled and without
1945 * preemption disabled. The cmpxchg is racy and may put the partial page
1946 * onto a random cpus partial slot.
1948 * If we did not find a slot then simply move all the partials to the
1949 * per node partial list.
1951 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
1953 struct page *oldpage;
1957 if (!s->cpu_partial)
1963 oldpage = this_cpu_read(s->cpu_slab->partial);
1966 pobjects = oldpage->pobjects;
1967 pages = oldpage->pages;
1968 if (drain && pobjects > s->cpu_partial) {
1969 unsigned long flags;
1971 * partial array is full. Move the existing
1972 * set to the per node partial list.
1974 local_irq_save(flags);
1975 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
1976 local_irq_restore(flags);
1980 stat(s, CPU_PARTIAL_DRAIN);
1985 pobjects += page->objects - page->inuse;
1987 page->pages = pages;
1988 page->pobjects = pobjects;
1989 page->next = oldpage;
1991 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
1994 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1996 stat(s, CPUSLAB_FLUSH);
1997 deactivate_slab(s, c->page, c->freelist);
1999 c->tid = next_tid(c->tid);
2007 * Called from IPI handler with interrupts disabled.
2009 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2011 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2017 unfreeze_partials(s, c);
2021 static void flush_cpu_slab(void *d)
2023 struct kmem_cache *s = d;
2025 __flush_cpu_slab(s, smp_processor_id());
2028 static bool has_cpu_slab(int cpu, void *info)
2030 struct kmem_cache *s = info;
2031 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2033 return c->page || c->partial;
2036 static void flush_all(struct kmem_cache *s)
2038 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2042 * Check if the objects in a per cpu structure fit numa
2043 * locality expectations.
2045 static inline int node_match(struct page *page, int node)
2048 if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2054 static int count_free(struct page *page)
2056 return page->objects - page->inuse;
2059 static unsigned long count_partial(struct kmem_cache_node *n,
2060 int (*get_count)(struct page *))
2062 unsigned long flags;
2063 unsigned long x = 0;
2066 spin_lock_irqsave(&n->list_lock, flags);
2067 list_for_each_entry(page, &n->partial, lru)
2068 x += get_count(page);
2069 spin_unlock_irqrestore(&n->list_lock, flags);
2073 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2075 #ifdef CONFIG_SLUB_DEBUG
2076 return atomic_long_read(&n->total_objects);
2082 static noinline void
2083 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2088 "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2090 printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
2091 "default order: %d, min order: %d\n", s->name, s->object_size,
2092 s->size, oo_order(s->oo), oo_order(s->min));
2094 if (oo_order(s->min) > get_order(s->object_size))
2095 printk(KERN_WARNING " %s debugging increased min order, use "
2096 "slub_debug=O to disable.\n", s->name);
2098 for_each_online_node(node) {
2099 struct kmem_cache_node *n = get_node(s, node);
2100 unsigned long nr_slabs;
2101 unsigned long nr_objs;
2102 unsigned long nr_free;
2107 nr_free = count_partial(n, count_free);
2108 nr_slabs = node_nr_slabs(n);
2109 nr_objs = node_nr_objs(n);
2112 " node %d: slabs: %ld, objs: %ld, free: %ld\n",
2113 node, nr_slabs, nr_objs, nr_free);
2117 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2118 int node, struct kmem_cache_cpu **pc)
2121 struct kmem_cache_cpu *c = *pc;
2124 freelist = get_partial(s, flags, node, c);
2129 page = new_slab(s, flags, node);
2131 c = __this_cpu_ptr(s->cpu_slab);
2136 * No other reference to the page yet so we can
2137 * muck around with it freely without cmpxchg
2139 freelist = page->freelist;
2140 page->freelist = NULL;
2142 stat(s, ALLOC_SLAB);
2151 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2153 if (unlikely(PageSlabPfmemalloc(page)))
2154 return gfp_pfmemalloc_allowed(gfpflags);
2160 * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
2161 * or deactivate the page.
2163 * The page is still frozen if the return value is not NULL.
2165 * If this function returns NULL then the page has been unfrozen.
2167 * This function must be called with interrupt disabled.
2169 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2172 unsigned long counters;
2176 freelist = page->freelist;
2177 counters = page->counters;
2179 new.counters = counters;
2180 VM_BUG_ON(!new.frozen);
2182 new.inuse = page->objects;
2183 new.frozen = freelist != NULL;
2185 } while (!__cmpxchg_double_slab(s, page,
2194 * Slow path. The lockless freelist is empty or we need to perform
2197 * Processing is still very fast if new objects have been freed to the
2198 * regular freelist. In that case we simply take over the regular freelist
2199 * as the lockless freelist and zap the regular freelist.
2201 * If that is not working then we fall back to the partial lists. We take the
2202 * first element of the freelist as the object to allocate now and move the
2203 * rest of the freelist to the lockless freelist.
2205 * And if we were unable to get a new slab from the partial slab lists then
2206 * we need to allocate a new slab. This is the slowest path since it involves
2207 * a call to the page allocator and the setup of a new slab.
2209 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2210 unsigned long addr, struct kmem_cache_cpu *c)
2214 unsigned long flags;
2216 local_irq_save(flags);
2217 #ifdef CONFIG_PREEMPT
2219 * We may have been preempted and rescheduled on a different
2220 * cpu before disabling interrupts. Need to reload cpu area
2223 c = this_cpu_ptr(s->cpu_slab);
2231 if (unlikely(!node_match(page, node))) {
2232 stat(s, ALLOC_NODE_MISMATCH);
2233 deactivate_slab(s, page, c->freelist);
2240 * By rights, we should be searching for a slab page that was
2241 * PFMEMALLOC but right now, we are losing the pfmemalloc
2242 * information when the page leaves the per-cpu allocator
2244 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2245 deactivate_slab(s, page, c->freelist);
2251 /* must check again c->freelist in case of cpu migration or IRQ */
2252 freelist = c->freelist;
2256 stat(s, ALLOC_SLOWPATH);
2258 freelist = get_freelist(s, page);
2262 stat(s, DEACTIVATE_BYPASS);
2266 stat(s, ALLOC_REFILL);
2270 * freelist is pointing to the list of objects to be used.
2271 * page is pointing to the page from which the objects are obtained.
2272 * That page must be frozen for per cpu allocations to work.
2274 VM_BUG_ON(!c->page->frozen);
2275 c->freelist = get_freepointer(s, freelist);
2276 c->tid = next_tid(c->tid);
2277 local_irq_restore(flags);
2283 page = c->page = c->partial;
2284 c->partial = page->next;
2285 stat(s, CPU_PARTIAL_ALLOC);
2290 freelist = new_slab_objects(s, gfpflags, node, &c);
2292 if (unlikely(!freelist)) {
2293 if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2294 slab_out_of_memory(s, gfpflags, node);
2296 local_irq_restore(flags);
2301 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2304 /* Only entered in the debug case */
2305 if (kmem_cache_debug(s) && !alloc_debug_processing(s, page, freelist, addr))
2306 goto new_slab; /* Slab failed checks. Next slab needed */
2308 deactivate_slab(s, page, get_freepointer(s, freelist));
2311 local_irq_restore(flags);
2316 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2317 * have the fastpath folded into their functions. So no function call
2318 * overhead for requests that can be satisfied on the fastpath.
2320 * The fastpath works by first checking if the lockless freelist can be used.
2321 * If not then __slab_alloc is called for slow processing.
2323 * Otherwise we can simply pick the next object from the lockless free list.
2325 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2326 gfp_t gfpflags, int node, unsigned long addr)
2329 struct kmem_cache_cpu *c;
2333 if (slab_pre_alloc_hook(s, gfpflags))
2336 s = memcg_kmem_get_cache(s, gfpflags);
2339 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2340 * enabled. We may switch back and forth between cpus while
2341 * reading from one cpu area. That does not matter as long
2342 * as we end up on the original cpu again when doing the cmpxchg.
2344 * Preemption is disabled for the retrieval of the tid because that
2345 * must occur from the current processor. We cannot allow rescheduling
2346 * on a different processor between the determination of the pointer
2347 * and the retrieval of the tid.
2350 c = __this_cpu_ptr(s->cpu_slab);
2353 * The transaction ids are globally unique per cpu and per operation on
2354 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2355 * occurs on the right processor and that there was no operation on the
2356 * linked list in between.
2361 object = c->freelist;
2363 if (unlikely(!object || !node_match(page, node)))
2364 object = __slab_alloc(s, gfpflags, node, addr, c);
2367 void *next_object = get_freepointer_safe(s, object);
2370 * The cmpxchg will only match if there was no additional
2371 * operation and if we are on the right processor.
2373 * The cmpxchg does the following atomically (without lock semantics!)
2374 * 1. Relocate first pointer to the current per cpu area.
2375 * 2. Verify that tid and freelist have not been changed
2376 * 3. If they were not changed replace tid and freelist
2378 * Since this is without lock semantics the protection is only against
2379 * code executing on this cpu *not* from access by other cpus.
2381 if (unlikely(!this_cpu_cmpxchg_double(
2382 s->cpu_slab->freelist, s->cpu_slab->tid,
2384 next_object, next_tid(tid)))) {
2386 note_cmpxchg_failure("slab_alloc", s, tid);
2389 prefetch_freepointer(s, next_object);
2390 stat(s, ALLOC_FASTPATH);
2393 if (unlikely(gfpflags & __GFP_ZERO) && object)
2394 memset(object, 0, s->object_size);
2396 slab_post_alloc_hook(s, gfpflags, object);
2401 static __always_inline void *slab_alloc(struct kmem_cache *s,
2402 gfp_t gfpflags, unsigned long addr)
2404 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2407 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2409 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2411 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size, s->size, gfpflags);
2415 EXPORT_SYMBOL(kmem_cache_alloc);
2417 #ifdef CONFIG_TRACING
2418 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2420 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2421 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2424 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2426 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
2428 void *ret = kmalloc_order(size, flags, order);
2429 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
2432 EXPORT_SYMBOL(kmalloc_order_trace);
2436 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2438 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2440 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2441 s->object_size, s->size, gfpflags, node);
2445 EXPORT_SYMBOL(kmem_cache_alloc_node);
2447 #ifdef CONFIG_TRACING
2448 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2450 int node, size_t size)
2452 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2454 trace_kmalloc_node(_RET_IP_, ret,
2455 size, s->size, gfpflags, node);
2458 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2463 * Slow patch handling. This may still be called frequently since objects
2464 * have a longer lifetime than the cpu slabs in most processing loads.
2466 * So we still attempt to reduce cache line usage. Just take the slab
2467 * lock and free the item. If there is no additional partial page
2468 * handling required then we can return immediately.
2470 static void __slab_free(struct kmem_cache *s, struct page *page,
2471 void *x, unsigned long addr)
2474 void **object = (void *)x;
2477 unsigned long counters;
2478 struct kmem_cache_node *n = NULL;
2479 unsigned long uninitialized_var(flags);
2481 stat(s, FREE_SLOWPATH);
2483 if (kmem_cache_debug(s) &&
2484 !(n = free_debug_processing(s, page, x, addr, &flags)))
2489 spin_unlock_irqrestore(&n->list_lock, flags);
2492 prior = page->freelist;
2493 counters = page->counters;
2494 set_freepointer(s, object, prior);
2495 new.counters = counters;
2496 was_frozen = new.frozen;
2498 if ((!new.inuse || !prior) && !was_frozen) {
2500 if (!kmem_cache_debug(s) && !prior)
2503 * Slab was on no list before and will be partially empty
2504 * We can defer the list move and instead freeze it.
2508 else { /* Needs to be taken off a list */
2510 n = get_node(s, page_to_nid(page));
2512 * Speculatively acquire the list_lock.
2513 * If the cmpxchg does not succeed then we may
2514 * drop the list_lock without any processing.
2516 * Otherwise the list_lock will synchronize with
2517 * other processors updating the list of slabs.
2519 spin_lock_irqsave(&n->list_lock, flags);
2524 } while (!cmpxchg_double_slab(s, page,
2526 object, new.counters,
2532 * If we just froze the page then put it onto the
2533 * per cpu partial list.
2535 if (new.frozen && !was_frozen) {
2536 put_cpu_partial(s, page, 1);
2537 stat(s, CPU_PARTIAL_FREE);
2540 * The list lock was not taken therefore no list
2541 * activity can be necessary.
2544 stat(s, FREE_FROZEN);
2548 if (unlikely(!new.inuse && n->nr_partial > s->min_partial))
2552 * Objects left in the slab. If it was not on the partial list before
2555 if (kmem_cache_debug(s) && unlikely(!prior)) {
2556 remove_full(s, page);
2557 add_partial(n, page, DEACTIVATE_TO_TAIL);
2558 stat(s, FREE_ADD_PARTIAL);
2560 spin_unlock_irqrestore(&n->list_lock, flags);
2566 * Slab on the partial list.
2568 remove_partial(n, page);
2569 stat(s, FREE_REMOVE_PARTIAL);
2571 /* Slab must be on the full list */
2572 remove_full(s, page);
2574 spin_unlock_irqrestore(&n->list_lock, flags);
2576 discard_slab(s, page);
2580 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2581 * can perform fastpath freeing without additional function calls.
2583 * The fastpath is only possible if we are freeing to the current cpu slab
2584 * of this processor. This typically the case if we have just allocated
2587 * If fastpath is not possible then fall back to __slab_free where we deal
2588 * with all sorts of special processing.
2590 static __always_inline void slab_free(struct kmem_cache *s,
2591 struct page *page, void *x, unsigned long addr)
2593 void **object = (void *)x;
2594 struct kmem_cache_cpu *c;
2597 slab_free_hook(s, x);
2601 * Determine the currently cpus per cpu slab.
2602 * The cpu may change afterward. However that does not matter since
2603 * data is retrieved via this pointer. If we are on the same cpu
2604 * during the cmpxchg then the free will succedd.
2607 c = __this_cpu_ptr(s->cpu_slab);
2612 if (likely(page == c->page)) {
2613 set_freepointer(s, object, c->freelist);
2615 if (unlikely(!this_cpu_cmpxchg_double(
2616 s->cpu_slab->freelist, s->cpu_slab->tid,
2618 object, next_tid(tid)))) {
2620 note_cmpxchg_failure("slab_free", s, tid);
2623 stat(s, FREE_FASTPATH);
2625 __slab_free(s, page, x, addr);
2629 void kmem_cache_free(struct kmem_cache *s, void *x)
2631 s = cache_from_obj(s, x);
2634 slab_free(s, virt_to_head_page(x), x, _RET_IP_);
2635 trace_kmem_cache_free(_RET_IP_, x);
2637 EXPORT_SYMBOL(kmem_cache_free);
2640 * Object placement in a slab is made very easy because we always start at
2641 * offset 0. If we tune the size of the object to the alignment then we can
2642 * get the required alignment by putting one properly sized object after
2645 * Notice that the allocation order determines the sizes of the per cpu
2646 * caches. Each processor has always one slab available for allocations.
2647 * Increasing the allocation order reduces the number of times that slabs
2648 * must be moved on and off the partial lists and is therefore a factor in
2653 * Mininum / Maximum order of slab pages. This influences locking overhead
2654 * and slab fragmentation. A higher order reduces the number of partial slabs
2655 * and increases the number of allocations possible without having to
2656 * take the list_lock.
2658 static int slub_min_order;
2659 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2660 static int slub_min_objects;
2663 * Merge control. If this is set then no merging of slab caches will occur.
2664 * (Could be removed. This was introduced to pacify the merge skeptics.)
2666 static int slub_nomerge;
2669 * Calculate the order of allocation given an slab object size.
2671 * The order of allocation has significant impact on performance and other
2672 * system components. Generally order 0 allocations should be preferred since
2673 * order 0 does not cause fragmentation in the page allocator. Larger objects
2674 * be problematic to put into order 0 slabs because there may be too much
2675 * unused space left. We go to a higher order if more than 1/16th of the slab
2678 * In order to reach satisfactory performance we must ensure that a minimum
2679 * number of objects is in one slab. Otherwise we may generate too much
2680 * activity on the partial lists which requires taking the list_lock. This is
2681 * less a concern for large slabs though which are rarely used.
2683 * slub_max_order specifies the order where we begin to stop considering the
2684 * number of objects in a slab as critical. If we reach slub_max_order then
2685 * we try to keep the page order as low as possible. So we accept more waste
2686 * of space in favor of a small page order.
2688 * Higher order allocations also allow the placement of more objects in a
2689 * slab and thereby reduce object handling overhead. If the user has
2690 * requested a higher mininum order then we start with that one instead of
2691 * the smallest order which will fit the object.
2693 static inline int slab_order(int size, int min_objects,
2694 int max_order, int fract_leftover, int reserved)
2698 int min_order = slub_min_order;
2700 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2701 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2703 for (order = max(min_order,
2704 fls(min_objects * size - 1) - PAGE_SHIFT);
2705 order <= max_order; order++) {
2707 unsigned long slab_size = PAGE_SIZE << order;
2709 if (slab_size < min_objects * size + reserved)
2712 rem = (slab_size - reserved) % size;
2714 if (rem <= slab_size / fract_leftover)
2722 static inline int calculate_order(int size, int reserved)
2730 * Attempt to find best configuration for a slab. This
2731 * works by first attempting to generate a layout with
2732 * the best configuration and backing off gradually.
2734 * First we reduce the acceptable waste in a slab. Then
2735 * we reduce the minimum objects required in a slab.
2737 min_objects = slub_min_objects;
2739 min_objects = 4 * (fls(nr_cpu_ids) + 1);
2740 max_objects = order_objects(slub_max_order, size, reserved);
2741 min_objects = min(min_objects, max_objects);
2743 while (min_objects > 1) {
2745 while (fraction >= 4) {
2746 order = slab_order(size, min_objects,
2747 slub_max_order, fraction, reserved);
2748 if (order <= slub_max_order)
2756 * We were unable to place multiple objects in a slab. Now
2757 * lets see if we can place a single object there.
2759 order = slab_order(size, 1, slub_max_order, 1, reserved);
2760 if (order <= slub_max_order)
2764 * Doh this slab cannot be placed using slub_max_order.
2766 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2767 if (order < MAX_ORDER)
2773 init_kmem_cache_node(struct kmem_cache_node *n)
2776 spin_lock_init(&n->list_lock);
2777 INIT_LIST_HEAD(&n->partial);
2778 #ifdef CONFIG_SLUB_DEBUG
2779 atomic_long_set(&n->nr_slabs, 0);
2780 atomic_long_set(&n->total_objects, 0);
2781 INIT_LIST_HEAD(&n->full);
2785 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2787 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2788 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
2791 * Must align to double word boundary for the double cmpxchg
2792 * instructions to work; see __pcpu_double_call_return_bool().
2794 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2795 2 * sizeof(void *));
2800 init_kmem_cache_cpus(s);
2805 static struct kmem_cache *kmem_cache_node;
2808 * No kmalloc_node yet so do it by hand. We know that this is the first
2809 * slab on the node for this slabcache. There are no concurrent accesses
2812 * Note that this function only works on the kmalloc_node_cache
2813 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2814 * memory on a fresh node that has no slab structures yet.
2816 static void early_kmem_cache_node_alloc(int node)
2819 struct kmem_cache_node *n;
2821 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2823 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2826 if (page_to_nid(page) != node) {
2827 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2829 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2830 "in order to be able to continue\n");
2835 page->freelist = get_freepointer(kmem_cache_node, n);
2838 kmem_cache_node->node[node] = n;
2839 #ifdef CONFIG_SLUB_DEBUG
2840 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2841 init_tracking(kmem_cache_node, n);
2843 init_kmem_cache_node(n);
2844 inc_slabs_node(kmem_cache_node, node, page->objects);
2846 add_partial(n, page, DEACTIVATE_TO_HEAD);
2849 static void free_kmem_cache_nodes(struct kmem_cache *s)
2853 for_each_node_state(node, N_NORMAL_MEMORY) {
2854 struct kmem_cache_node *n = s->node[node];
2857 kmem_cache_free(kmem_cache_node, n);
2859 s->node[node] = NULL;
2863 static int init_kmem_cache_nodes(struct kmem_cache *s)
2867 for_each_node_state(node, N_NORMAL_MEMORY) {
2868 struct kmem_cache_node *n;
2870 if (slab_state == DOWN) {
2871 early_kmem_cache_node_alloc(node);
2874 n = kmem_cache_alloc_node(kmem_cache_node,
2878 free_kmem_cache_nodes(s);
2883 init_kmem_cache_node(n);
2888 static void set_min_partial(struct kmem_cache *s, unsigned long min)
2890 if (min < MIN_PARTIAL)
2892 else if (min > MAX_PARTIAL)
2894 s->min_partial = min;
2898 * calculate_sizes() determines the order and the distribution of data within
2901 static int calculate_sizes(struct kmem_cache *s, int forced_order)
2903 unsigned long flags = s->flags;
2904 unsigned long size = s->object_size;
2908 * Round up object size to the next word boundary. We can only
2909 * place the free pointer at word boundaries and this determines
2910 * the possible location of the free pointer.
2912 size = ALIGN(size, sizeof(void *));
2914 #ifdef CONFIG_SLUB_DEBUG
2916 * Determine if we can poison the object itself. If the user of
2917 * the slab may touch the object after free or before allocation
2918 * then we should never poison the object itself.
2920 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2922 s->flags |= __OBJECT_POISON;
2924 s->flags &= ~__OBJECT_POISON;
2928 * If we are Redzoning then check if there is some space between the
2929 * end of the object and the free pointer. If not then add an
2930 * additional word to have some bytes to store Redzone information.
2932 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
2933 size += sizeof(void *);
2937 * With that we have determined the number of bytes in actual use
2938 * by the object. This is the potential offset to the free pointer.
2942 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2945 * Relocate free pointer after the object if it is not
2946 * permitted to overwrite the first word of the object on
2949 * This is the case if we do RCU, have a constructor or
2950 * destructor or are poisoning the objects.
2953 size += sizeof(void *);
2956 #ifdef CONFIG_SLUB_DEBUG
2957 if (flags & SLAB_STORE_USER)
2959 * Need to store information about allocs and frees after
2962 size += 2 * sizeof(struct track);
2964 if (flags & SLAB_RED_ZONE)
2966 * Add some empty padding so that we can catch
2967 * overwrites from earlier objects rather than let
2968 * tracking information or the free pointer be
2969 * corrupted if a user writes before the start
2972 size += sizeof(void *);
2976 * SLUB stores one object immediately after another beginning from
2977 * offset 0. In order to align the objects we have to simply size
2978 * each object to conform to the alignment.
2980 size = ALIGN(size, s->align);
2982 if (forced_order >= 0)
2983 order = forced_order;
2985 order = calculate_order(size, s->reserved);
2992 s->allocflags |= __GFP_COMP;
2994 if (s->flags & SLAB_CACHE_DMA)
2995 s->allocflags |= GFP_DMA;
2997 if (s->flags & SLAB_RECLAIM_ACCOUNT)
2998 s->allocflags |= __GFP_RECLAIMABLE;
3001 * Determine the number of objects per slab
3003 s->oo = oo_make(order, size, s->reserved);
3004 s->min = oo_make(get_order(size), size, s->reserved);
3005 if (oo_objects(s->oo) > oo_objects(s->max))
3008 return !!oo_objects(s->oo);
3011 static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3013 s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3016 if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3017 s->reserved = sizeof(struct rcu_head);
3019 if (!calculate_sizes(s, -1))
3021 if (disable_higher_order_debug) {
3023 * Disable debugging flags that store metadata if the min slab
3026 if (get_order(s->size) > get_order(s->object_size)) {
3027 s->flags &= ~DEBUG_METADATA_FLAGS;
3029 if (!calculate_sizes(s, -1))
3034 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3035 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3036 if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
3037 /* Enable fast mode */
3038 s->flags |= __CMPXCHG_DOUBLE;
3042 * The larger the object size is, the more pages we want on the partial
3043 * list to avoid pounding the page allocator excessively.
3045 set_min_partial(s, ilog2(s->size) / 2);
3048 * cpu_partial determined the maximum number of objects kept in the
3049 * per cpu partial lists of a processor.
3051 * Per cpu partial lists mainly contain slabs that just have one
3052 * object freed. If they are used for allocation then they can be
3053 * filled up again with minimal effort. The slab will never hit the
3054 * per node partial lists and therefore no locking will be required.
3056 * This setting also determines
3058 * A) The number of objects from per cpu partial slabs dumped to the
3059 * per node list when we reach the limit.
3060 * B) The number of objects in cpu partial slabs to extract from the
3061 * per node list when we run out of per cpu objects. We only fetch 50%
3062 * to keep some capacity around for frees.
3064 if (kmem_cache_debug(s))
3066 else if (s->size >= PAGE_SIZE)
3068 else if (s->size >= 1024)
3070 else if (s->size >= 256)
3071 s->cpu_partial = 13;
3073 s->cpu_partial = 30;
3076 s->remote_node_defrag_ratio = 1000;
3078 if (!init_kmem_cache_nodes(s))
3081 if (alloc_kmem_cache_cpus(s))
3084 free_kmem_cache_nodes(s);
3086 if (flags & SLAB_PANIC)
3087 panic("Cannot create slab %s size=%lu realsize=%u "
3088 "order=%u offset=%u flags=%lx\n",
3089 s->name, (unsigned long)s->size, s->size, oo_order(s->oo),
3094 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3097 #ifdef CONFIG_SLUB_DEBUG
3098 void *addr = page_address(page);
3100 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3101 sizeof(long), GFP_ATOMIC);
3104 slab_err(s, page, text, s->name);
3107 get_map(s, page, map);
3108 for_each_object(p, s, addr, page->objects) {
3110 if (!test_bit(slab_index(p, s, addr), map)) {
3111 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
3113 print_tracking(s, p);
3122 * Attempt to free all partial slabs on a node.
3123 * This is called from kmem_cache_close(). We must be the last thread
3124 * using the cache and therefore we do not need to lock anymore.
3126 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3128 struct page *page, *h;
3130 list_for_each_entry_safe(page, h, &n->partial, lru) {
3132 remove_partial(n, page);
3133 discard_slab(s, page);
3135 list_slab_objects(s, page,
3136 "Objects remaining in %s on kmem_cache_close()");
3142 * Release all resources used by a slab cache.
3144 static inline int kmem_cache_close(struct kmem_cache *s)
3149 /* Attempt to free all objects */
3150 for_each_node_state(node, N_NORMAL_MEMORY) {
3151 struct kmem_cache_node *n = get_node(s, node);
3154 if (n->nr_partial || slabs_node(s, node))
3157 free_percpu(s->cpu_slab);
3158 free_kmem_cache_nodes(s);
3162 int __kmem_cache_shutdown(struct kmem_cache *s)
3164 int rc = kmem_cache_close(s);
3168 * We do the same lock strategy around sysfs_slab_add, see
3169 * __kmem_cache_create. Because this is pretty much the last
3170 * operation we do and the lock will be released shortly after
3171 * that in slab_common.c, we could just move sysfs_slab_remove
3172 * to a later point in common code. We should do that when we
3173 * have a common sysfs framework for all allocators.
3175 mutex_unlock(&slab_mutex);
3176 sysfs_slab_remove(s);
3177 mutex_lock(&slab_mutex);
3183 /********************************************************************
3185 *******************************************************************/
3187 static int __init setup_slub_min_order(char *str)
3189 get_option(&str, &slub_min_order);
3194 __setup("slub_min_order=", setup_slub_min_order);
3196 static int __init setup_slub_max_order(char *str)
3198 get_option(&str, &slub_max_order);
3199 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3204 __setup("slub_max_order=", setup_slub_max_order);
3206 static int __init setup_slub_min_objects(char *str)
3208 get_option(&str, &slub_min_objects);
3213 __setup("slub_min_objects=", setup_slub_min_objects);
3215 static int __init setup_slub_nomerge(char *str)
3221 __setup("slub_nomerge", setup_slub_nomerge);
3223 void *__kmalloc(size_t size, gfp_t flags)
3225 struct kmem_cache *s;
3228 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3229 return kmalloc_large(size, flags);
3231 s = kmalloc_slab(size, flags);
3233 if (unlikely(ZERO_OR_NULL_PTR(s)))
3236 ret = slab_alloc(s, flags, _RET_IP_);
3238 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3242 EXPORT_SYMBOL(__kmalloc);
3245 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3250 flags |= __GFP_COMP | __GFP_NOTRACK | __GFP_KMEMCG;
3251 page = alloc_pages_node(node, flags, get_order(size));
3253 ptr = page_address(page);
3255 kmemleak_alloc(ptr, size, 1, flags);
3259 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3261 struct kmem_cache *s;
3264 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3265 ret = kmalloc_large_node(size, flags, node);
3267 trace_kmalloc_node(_RET_IP_, ret,
3268 size, PAGE_SIZE << get_order(size),
3274 s = kmalloc_slab(size, flags);
3276 if (unlikely(ZERO_OR_NULL_PTR(s)))
3279 ret = slab_alloc_node(s, flags, node, _RET_IP_);
3281 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3285 EXPORT_SYMBOL(__kmalloc_node);
3288 size_t ksize(const void *object)
3292 if (unlikely(object == ZERO_SIZE_PTR))
3295 page = virt_to_head_page(object);
3297 if (unlikely(!PageSlab(page))) {
3298 WARN_ON(!PageCompound(page));
3299 return PAGE_SIZE << compound_order(page);
3302 return slab_ksize(page->slab_cache);
3304 EXPORT_SYMBOL(ksize);
3306 #ifdef CONFIG_SLUB_DEBUG
3307 bool verify_mem_not_deleted(const void *x)
3310 void *object = (void *)x;
3311 unsigned long flags;
3314 if (unlikely(ZERO_OR_NULL_PTR(x)))
3317 local_irq_save(flags);
3319 page = virt_to_head_page(x);
3320 if (unlikely(!PageSlab(page))) {
3321 /* maybe it was from stack? */
3327 if (on_freelist(page->slab_cache, page, object)) {
3328 object_err(page->slab_cache, page, object, "Object is on free-list");
3336 local_irq_restore(flags);
3339 EXPORT_SYMBOL(verify_mem_not_deleted);
3342 void kfree(const void *x)
3345 void *object = (void *)x;
3347 trace_kfree(_RET_IP_, x);
3349 if (unlikely(ZERO_OR_NULL_PTR(x)))
3352 page = virt_to_head_page(x);
3353 if (unlikely(!PageSlab(page))) {
3354 BUG_ON(!PageCompound(page));
3356 __free_memcg_kmem_pages(page, compound_order(page));
3359 slab_free(page->slab_cache, page, object, _RET_IP_);
3361 EXPORT_SYMBOL(kfree);
3364 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3365 * the remaining slabs by the number of items in use. The slabs with the
3366 * most items in use come first. New allocations will then fill those up
3367 * and thus they can be removed from the partial lists.
3369 * The slabs with the least items are placed last. This results in them
3370 * being allocated from last increasing the chance that the last objects
3371 * are freed in them.
3373 int kmem_cache_shrink(struct kmem_cache *s)
3377 struct kmem_cache_node *n;
3380 int objects = oo_objects(s->max);
3381 struct list_head *slabs_by_inuse =
3382 kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3383 unsigned long flags;
3385 if (!slabs_by_inuse)
3389 for_each_node_state(node, N_NORMAL_MEMORY) {
3390 n = get_node(s, node);
3395 for (i = 0; i < objects; i++)
3396 INIT_LIST_HEAD(slabs_by_inuse + i);
3398 spin_lock_irqsave(&n->list_lock, flags);
3401 * Build lists indexed by the items in use in each slab.
3403 * Note that concurrent frees may occur while we hold the
3404 * list_lock. page->inuse here is the upper limit.
3406 list_for_each_entry_safe(page, t, &n->partial, lru) {
3407 list_move(&page->lru, slabs_by_inuse + page->inuse);
3413 * Rebuild the partial list with the slabs filled up most
3414 * first and the least used slabs at the end.
3416 for (i = objects - 1; i > 0; i--)
3417 list_splice(slabs_by_inuse + i, n->partial.prev);
3419 spin_unlock_irqrestore(&n->list_lock, flags);
3421 /* Release empty slabs */
3422 list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
3423 discard_slab(s, page);
3426 kfree(slabs_by_inuse);
3429 EXPORT_SYMBOL(kmem_cache_shrink);
3431 #if defined(CONFIG_MEMORY_HOTPLUG)
3432 static int slab_mem_going_offline_callback(void *arg)
3434 struct kmem_cache *s;
3436 mutex_lock(&slab_mutex);
3437 list_for_each_entry(s, &slab_caches, list)
3438 kmem_cache_shrink(s);
3439 mutex_unlock(&slab_mutex);
3444 static void slab_mem_offline_callback(void *arg)
3446 struct kmem_cache_node *n;
3447 struct kmem_cache *s;
3448 struct memory_notify *marg = arg;
3451 offline_node = marg->status_change_nid_normal;
3454 * If the node still has available memory. we need kmem_cache_node
3457 if (offline_node < 0)
3460 mutex_lock(&slab_mutex);
3461 list_for_each_entry(s, &slab_caches, list) {
3462 n = get_node(s, offline_node);
3465 * if n->nr_slabs > 0, slabs still exist on the node
3466 * that is going down. We were unable to free them,
3467 * and offline_pages() function shouldn't call this
3468 * callback. So, we must fail.
3470 BUG_ON(slabs_node(s, offline_node));
3472 s->node[offline_node] = NULL;
3473 kmem_cache_free(kmem_cache_node, n);
3476 mutex_unlock(&slab_mutex);
3479 static int slab_mem_going_online_callback(void *arg)
3481 struct kmem_cache_node *n;
3482 struct kmem_cache *s;
3483 struct memory_notify *marg = arg;
3484 int nid = marg->status_change_nid_normal;
3488 * If the node's memory is already available, then kmem_cache_node is
3489 * already created. Nothing to do.
3495 * We are bringing a node online. No memory is available yet. We must
3496 * allocate a kmem_cache_node structure in order to bring the node
3499 mutex_lock(&slab_mutex);
3500 list_for_each_entry(s, &slab_caches, list) {
3502 * XXX: kmem_cache_alloc_node will fallback to other nodes
3503 * since memory is not yet available from the node that
3506 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3511 init_kmem_cache_node(n);
3515 mutex_unlock(&slab_mutex);
3519 static int slab_memory_callback(struct notifier_block *self,
3520 unsigned long action, void *arg)
3525 case MEM_GOING_ONLINE:
3526 ret = slab_mem_going_online_callback(arg);
3528 case MEM_GOING_OFFLINE:
3529 ret = slab_mem_going_offline_callback(arg);
3532 case MEM_CANCEL_ONLINE:
3533 slab_mem_offline_callback(arg);
3536 case MEM_CANCEL_OFFLINE:
3540 ret = notifier_from_errno(ret);
3546 #endif /* CONFIG_MEMORY_HOTPLUG */
3548 /********************************************************************
3549 * Basic setup of slabs
3550 *******************************************************************/
3553 * Used for early kmem_cache structures that were allocated using
3554 * the page allocator. Allocate them properly then fix up the pointers
3555 * that may be pointing to the wrong kmem_cache structure.
3558 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
3561 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
3563 memcpy(s, static_cache, kmem_cache->object_size);
3566 * This runs very early, and only the boot processor is supposed to be
3567 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3570 __flush_cpu_slab(s, smp_processor_id());
3571 for_each_node_state(node, N_NORMAL_MEMORY) {
3572 struct kmem_cache_node *n = get_node(s, node);
3576 list_for_each_entry(p, &n->partial, lru)
3579 #ifdef CONFIG_SLUB_DEBUG
3580 list_for_each_entry(p, &n->full, lru)
3585 list_add(&s->list, &slab_caches);
3589 void __init kmem_cache_init(void)
3591 static __initdata struct kmem_cache boot_kmem_cache,
3592 boot_kmem_cache_node;
3594 if (debug_guardpage_minorder())
3597 kmem_cache_node = &boot_kmem_cache_node;
3598 kmem_cache = &boot_kmem_cache;
3600 create_boot_cache(kmem_cache_node, "kmem_cache_node",
3601 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
3603 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3605 /* Able to allocate the per node structures */
3606 slab_state = PARTIAL;
3608 create_boot_cache(kmem_cache, "kmem_cache",
3609 offsetof(struct kmem_cache, node) +
3610 nr_node_ids * sizeof(struct kmem_cache_node *),
3611 SLAB_HWCACHE_ALIGN);
3613 kmem_cache = bootstrap(&boot_kmem_cache);
3616 * Allocate kmem_cache_node properly from the kmem_cache slab.
3617 * kmem_cache_node is separately allocated so no need to
3618 * update any list pointers.
3620 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
3622 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3623 create_kmalloc_caches(0);
3626 register_cpu_notifier(&slab_notifier);
3630 "SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d,"
3631 " CPUs=%d, Nodes=%d\n",
3633 slub_min_order, slub_max_order, slub_min_objects,
3634 nr_cpu_ids, nr_node_ids);
3637 void __init kmem_cache_init_late(void)
3642 * Find a mergeable slab cache
3644 static int slab_unmergeable(struct kmem_cache *s)
3646 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3653 * We may have set a slab to be unmergeable during bootstrap.
3655 if (s->refcount < 0)
3661 static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
3662 size_t align, unsigned long flags, const char *name,
3663 void (*ctor)(void *))
3665 struct kmem_cache *s;
3667 if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3673 size = ALIGN(size, sizeof(void *));
3674 align = calculate_alignment(flags, align, size);
3675 size = ALIGN(size, align);
3676 flags = kmem_cache_flags(size, flags, name, NULL);
3678 list_for_each_entry(s, &slab_caches, list) {
3679 if (slab_unmergeable(s))
3685 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3688 * Check if alignment is compatible.
3689 * Courtesy of Adrian Drzewiecki
3691 if ((s->size & ~(align - 1)) != s->size)
3694 if (s->size - size >= sizeof(void *))
3697 if (!cache_match_memcg(s, memcg))
3706 __kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
3707 size_t align, unsigned long flags, void (*ctor)(void *))
3709 struct kmem_cache *s;
3711 s = find_mergeable(memcg, size, align, flags, name, ctor);
3715 * Adjust the object sizes so that we clear
3716 * the complete object on kzalloc.
3718 s->object_size = max(s->object_size, (int)size);
3719 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3721 if (sysfs_slab_alias(s, name)) {
3730 int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
3734 err = kmem_cache_open(s, flags);
3738 /* Mutex is not taken during early boot */
3739 if (slab_state <= UP)
3742 memcg_propagate_slab_attrs(s);
3743 mutex_unlock(&slab_mutex);
3744 err = sysfs_slab_add(s);
3745 mutex_lock(&slab_mutex);
3748 kmem_cache_close(s);
3755 * Use the cpu notifier to insure that the cpu slabs are flushed when
3758 static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3759 unsigned long action, void *hcpu)
3761 long cpu = (long)hcpu;
3762 struct kmem_cache *s;
3763 unsigned long flags;
3766 case CPU_UP_CANCELED:
3767 case CPU_UP_CANCELED_FROZEN:
3769 case CPU_DEAD_FROZEN:
3770 mutex_lock(&slab_mutex);
3771 list_for_each_entry(s, &slab_caches, list) {
3772 local_irq_save(flags);
3773 __flush_cpu_slab(s, cpu);
3774 local_irq_restore(flags);
3776 mutex_unlock(&slab_mutex);
3784 static struct notifier_block __cpuinitdata slab_notifier = {
3785 .notifier_call = slab_cpuup_callback
3790 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
3792 struct kmem_cache *s;
3795 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3796 return kmalloc_large(size, gfpflags);
3798 s = kmalloc_slab(size, gfpflags);
3800 if (unlikely(ZERO_OR_NULL_PTR(s)))
3803 ret = slab_alloc(s, gfpflags, caller);
3805 /* Honor the call site pointer we received. */
3806 trace_kmalloc(caller, ret, size, s->size, gfpflags);
3812 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3813 int node, unsigned long caller)
3815 struct kmem_cache *s;
3818 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3819 ret = kmalloc_large_node(size, gfpflags, node);
3821 trace_kmalloc_node(caller, ret,
3822 size, PAGE_SIZE << get_order(size),
3828 s = kmalloc_slab(size, gfpflags);
3830 if (unlikely(ZERO_OR_NULL_PTR(s)))
3833 ret = slab_alloc_node(s, gfpflags, node, caller);
3835 /* Honor the call site pointer we received. */
3836 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
3843 static int count_inuse(struct page *page)
3848 static int count_total(struct page *page)
3850 return page->objects;
3854 #ifdef CONFIG_SLUB_DEBUG
3855 static int validate_slab(struct kmem_cache *s, struct page *page,
3859 void *addr = page_address(page);
3861 if (!check_slab(s, page) ||
3862 !on_freelist(s, page, NULL))
3865 /* Now we know that a valid freelist exists */
3866 bitmap_zero(map, page->objects);
3868 get_map(s, page, map);
3869 for_each_object(p, s, addr, page->objects) {
3870 if (test_bit(slab_index(p, s, addr), map))
3871 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
3875 for_each_object(p, s, addr, page->objects)
3876 if (!test_bit(slab_index(p, s, addr), map))
3877 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
3882 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3886 validate_slab(s, page, map);
3890 static int validate_slab_node(struct kmem_cache *s,
3891 struct kmem_cache_node *n, unsigned long *map)
3893 unsigned long count = 0;
3895 unsigned long flags;
3897 spin_lock_irqsave(&n->list_lock, flags);
3899 list_for_each_entry(page, &n->partial, lru) {
3900 validate_slab_slab(s, page, map);
3903 if (count != n->nr_partial)
3904 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3905 "counter=%ld\n", s->name, count, n->nr_partial);
3907 if (!(s->flags & SLAB_STORE_USER))
3910 list_for_each_entry(page, &n->full, lru) {
3911 validate_slab_slab(s, page, map);
3914 if (count != atomic_long_read(&n->nr_slabs))
3915 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3916 "counter=%ld\n", s->name, count,
3917 atomic_long_read(&n->nr_slabs));
3920 spin_unlock_irqrestore(&n->list_lock, flags);
3924 static long validate_slab_cache(struct kmem_cache *s)
3927 unsigned long count = 0;
3928 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
3929 sizeof(unsigned long), GFP_KERNEL);
3935 for_each_node_state(node, N_NORMAL_MEMORY) {
3936 struct kmem_cache_node *n = get_node(s, node);
3938 count += validate_slab_node(s, n, map);
3944 * Generate lists of code addresses where slabcache objects are allocated
3949 unsigned long count;
3956 DECLARE_BITMAP(cpus, NR_CPUS);
3962 unsigned long count;
3963 struct location *loc;
3966 static void free_loc_track(struct loc_track *t)
3969 free_pages((unsigned long)t->loc,
3970 get_order(sizeof(struct location) * t->max));
3973 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
3978 order = get_order(sizeof(struct location) * max);
3980 l = (void *)__get_free_pages(flags, order);
3985 memcpy(l, t->loc, sizeof(struct location) * t->count);
3993 static int add_location(struct loc_track *t, struct kmem_cache *s,
3994 const struct track *track)
3996 long start, end, pos;
3998 unsigned long caddr;
3999 unsigned long age = jiffies - track->when;
4005 pos = start + (end - start + 1) / 2;
4008 * There is nothing at "end". If we end up there
4009 * we need to add something to before end.
4014 caddr = t->loc[pos].addr;
4015 if (track->addr == caddr) {
4021 if (age < l->min_time)
4023 if (age > l->max_time)
4026 if (track->pid < l->min_pid)
4027 l->min_pid = track->pid;
4028 if (track->pid > l->max_pid)
4029 l->max_pid = track->pid;
4031 cpumask_set_cpu(track->cpu,
4032 to_cpumask(l->cpus));
4034 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4038 if (track->addr < caddr)
4045 * Not found. Insert new tracking element.
4047 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4053 (t->count - pos) * sizeof(struct location));
4056 l->addr = track->addr;
4060 l->min_pid = track->pid;
4061 l->max_pid = track->pid;
4062 cpumask_clear(to_cpumask(l->cpus));
4063 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4064 nodes_clear(l->nodes);
4065 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4069 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4070 struct page *page, enum track_item alloc,
4073 void *addr = page_address(page);
4076 bitmap_zero(map, page->objects);
4077 get_map(s, page, map);
4079 for_each_object(p, s, addr, page->objects)
4080 if (!test_bit(slab_index(p, s, addr), map))
4081 add_location(t, s, get_track(s, p, alloc));
4084 static int list_locations(struct kmem_cache *s, char *buf,
4085 enum track_item alloc)
4089 struct loc_track t = { 0, 0, NULL };
4091 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4092 sizeof(unsigned long), GFP_KERNEL);
4094 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4097 return sprintf(buf, "Out of memory\n");
4099 /* Push back cpu slabs */
4102 for_each_node_state(node, N_NORMAL_MEMORY) {
4103 struct kmem_cache_node *n = get_node(s, node);
4104 unsigned long flags;
4107 if (!atomic_long_read(&n->nr_slabs))
4110 spin_lock_irqsave(&n->list_lock, flags);
4111 list_for_each_entry(page, &n->partial, lru)
4112 process_slab(&t, s, page, alloc, map);
4113 list_for_each_entry(page, &n->full, lru)
4114 process_slab(&t, s, page, alloc, map);
4115 spin_unlock_irqrestore(&n->list_lock, flags);
4118 for (i = 0; i < t.count; i++) {
4119 struct location *l = &t.loc[i];
4121 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4123 len += sprintf(buf + len, "%7ld ", l->count);
4126 len += sprintf(buf + len, "%pS", (void *)l->addr);
4128 len += sprintf(buf + len, "<not-available>");
4130 if (l->sum_time != l->min_time) {
4131 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4133 (long)div_u64(l->sum_time, l->count),
4136 len += sprintf(buf + len, " age=%ld",
4139 if (l->min_pid != l->max_pid)
4140 len += sprintf(buf + len, " pid=%ld-%ld",
4141 l->min_pid, l->max_pid);
4143 len += sprintf(buf + len, " pid=%ld",
4146 if (num_online_cpus() > 1 &&
4147 !cpumask_empty(to_cpumask(l->cpus)) &&
4148 len < PAGE_SIZE - 60) {
4149 len += sprintf(buf + len, " cpus=");
4150 len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4151 to_cpumask(l->cpus));
4154 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4155 len < PAGE_SIZE - 60) {
4156 len += sprintf(buf + len, " nodes=");
4157 len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4161 len += sprintf(buf + len, "\n");
4167 len += sprintf(buf, "No data\n");
4172 #ifdef SLUB_RESILIENCY_TEST
4173 static void resiliency_test(void)
4177 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4179 printk(KERN_ERR "SLUB resiliency testing\n");
4180 printk(KERN_ERR "-----------------------\n");
4181 printk(KERN_ERR "A. Corruption after allocation\n");
4183 p = kzalloc(16, GFP_KERNEL);
4185 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4186 " 0x12->0x%p\n\n", p + 16);
4188 validate_slab_cache(kmalloc_caches[4]);
4190 /* Hmmm... The next two are dangerous */
4191 p = kzalloc(32, GFP_KERNEL);
4192 p[32 + sizeof(void *)] = 0x34;
4193 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4194 " 0x34 -> -0x%p\n", p);
4196 "If allocated object is overwritten then not detectable\n\n");
4198 validate_slab_cache(kmalloc_caches[5]);
4199 p = kzalloc(64, GFP_KERNEL);
4200 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4202 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4205 "If allocated object is overwritten then not detectable\n\n");
4206 validate_slab_cache(kmalloc_caches[6]);
4208 printk(KERN_ERR "\nB. Corruption after free\n");
4209 p = kzalloc(128, GFP_KERNEL);
4212 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4213 validate_slab_cache(kmalloc_caches[7]);
4215 p = kzalloc(256, GFP_KERNEL);
4218 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4220 validate_slab_cache(kmalloc_caches[8]);
4222 p = kzalloc(512, GFP_KERNEL);
4225 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4226 validate_slab_cache(kmalloc_caches[9]);
4230 static void resiliency_test(void) {};
4235 enum slab_stat_type {
4236 SL_ALL, /* All slabs */
4237 SL_PARTIAL, /* Only partially allocated slabs */
4238 SL_CPU, /* Only slabs used for cpu caches */
4239 SL_OBJECTS, /* Determine allocated objects not slabs */
4240 SL_TOTAL /* Determine object capacity not slabs */
4243 #define SO_ALL (1 << SL_ALL)
4244 #define SO_PARTIAL (1 << SL_PARTIAL)
4245 #define SO_CPU (1 << SL_CPU)
4246 #define SO_OBJECTS (1 << SL_OBJECTS)
4247 #define SO_TOTAL (1 << SL_TOTAL)
4249 static ssize_t show_slab_objects(struct kmem_cache *s,
4250 char *buf, unsigned long flags)
4252 unsigned long total = 0;
4255 unsigned long *nodes;
4256 unsigned long *per_cpu;
4258 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4261 per_cpu = nodes + nr_node_ids;
4263 if (flags & SO_CPU) {
4266 for_each_possible_cpu(cpu) {
4267 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
4271 page = ACCESS_ONCE(c->page);
4275 node = page_to_nid(page);
4276 if (flags & SO_TOTAL)
4278 else if (flags & SO_OBJECTS)
4286 page = ACCESS_ONCE(c->partial);
4297 lock_memory_hotplug();
4298 #ifdef CONFIG_SLUB_DEBUG
4299 if (flags & SO_ALL) {
4300 for_each_node_state(node, N_NORMAL_MEMORY) {
4301 struct kmem_cache_node *n = get_node(s, node);
4303 if (flags & SO_TOTAL)
4304 x = atomic_long_read(&n->total_objects);
4305 else if (flags & SO_OBJECTS)
4306 x = atomic_long_read(&n->total_objects) -
4307 count_partial(n, count_free);
4310 x = atomic_long_read(&n->nr_slabs);
4317 if (flags & SO_PARTIAL) {
4318 for_each_node_state(node, N_NORMAL_MEMORY) {
4319 struct kmem_cache_node *n = get_node(s, node);
4321 if (flags & SO_TOTAL)
4322 x = count_partial(n, count_total);
4323 else if (flags & SO_OBJECTS)
4324 x = count_partial(n, count_inuse);
4331 x = sprintf(buf, "%lu", total);
4333 for_each_node_state(node, N_NORMAL_MEMORY)
4335 x += sprintf(buf + x, " N%d=%lu",
4338 unlock_memory_hotplug();
4340 return x + sprintf(buf + x, "\n");
4343 #ifdef CONFIG_SLUB_DEBUG
4344 static int any_slab_objects(struct kmem_cache *s)
4348 for_each_online_node(node) {
4349 struct kmem_cache_node *n = get_node(s, node);
4354 if (atomic_long_read(&n->total_objects))
4361 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4362 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4364 struct slab_attribute {
4365 struct attribute attr;
4366 ssize_t (*show)(struct kmem_cache *s, char *buf);
4367 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4370 #define SLAB_ATTR_RO(_name) \
4371 static struct slab_attribute _name##_attr = \
4372 __ATTR(_name, 0400, _name##_show, NULL)
4374 #define SLAB_ATTR(_name) \
4375 static struct slab_attribute _name##_attr = \
4376 __ATTR(_name, 0600, _name##_show, _name##_store)
4378 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4380 return sprintf(buf, "%d\n", s->size);
4382 SLAB_ATTR_RO(slab_size);
4384 static ssize_t align_show(struct kmem_cache *s, char *buf)
4386 return sprintf(buf, "%d\n", s->align);
4388 SLAB_ATTR_RO(align);
4390 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4392 return sprintf(buf, "%d\n", s->object_size);
4394 SLAB_ATTR_RO(object_size);
4396 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4398 return sprintf(buf, "%d\n", oo_objects(s->oo));
4400 SLAB_ATTR_RO(objs_per_slab);
4402 static ssize_t order_store(struct kmem_cache *s,
4403 const char *buf, size_t length)
4405 unsigned long order;
4408 err = strict_strtoul(buf, 10, &order);
4412 if (order > slub_max_order || order < slub_min_order)
4415 calculate_sizes(s, order);
4419 static ssize_t order_show(struct kmem_cache *s, char *buf)
4421 return sprintf(buf, "%d\n", oo_order(s->oo));
4425 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4427 return sprintf(buf, "%lu\n", s->min_partial);
4430 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4436 err = strict_strtoul(buf, 10, &min);
4440 set_min_partial(s, min);
4443 SLAB_ATTR(min_partial);
4445 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4447 return sprintf(buf, "%u\n", s->cpu_partial);
4450 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4453 unsigned long objects;
4456 err = strict_strtoul(buf, 10, &objects);
4459 if (objects && kmem_cache_debug(s))
4462 s->cpu_partial = objects;
4466 SLAB_ATTR(cpu_partial);
4468 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4472 return sprintf(buf, "%pS\n", s->ctor);
4476 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4478 return sprintf(buf, "%d\n", s->refcount - 1);
4480 SLAB_ATTR_RO(aliases);
4482 static ssize_t partial_show(struct kmem_cache *s, char *buf)
4484 return show_slab_objects(s, buf, SO_PARTIAL);
4486 SLAB_ATTR_RO(partial);
4488 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4490 return show_slab_objects(s, buf, SO_CPU);
4492 SLAB_ATTR_RO(cpu_slabs);
4494 static ssize_t objects_show(struct kmem_cache *s, char *buf)
4496 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4498 SLAB_ATTR_RO(objects);
4500 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4502 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4504 SLAB_ATTR_RO(objects_partial);
4506 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4513 for_each_online_cpu(cpu) {
4514 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4517 pages += page->pages;
4518 objects += page->pobjects;
4522 len = sprintf(buf, "%d(%d)", objects, pages);
4525 for_each_online_cpu(cpu) {
4526 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4528 if (page && len < PAGE_SIZE - 20)
4529 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4530 page->pobjects, page->pages);
4533 return len + sprintf(buf + len, "\n");
4535 SLAB_ATTR_RO(slabs_cpu_partial);
4537 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4539 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4542 static ssize_t reclaim_account_store(struct kmem_cache *s,
4543 const char *buf, size_t length)
4545 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4547 s->flags |= SLAB_RECLAIM_ACCOUNT;
4550 SLAB_ATTR(reclaim_account);
4552 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4554 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4556 SLAB_ATTR_RO(hwcache_align);
4558 #ifdef CONFIG_ZONE_DMA
4559 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4561 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4563 SLAB_ATTR_RO(cache_dma);
4566 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4568 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4570 SLAB_ATTR_RO(destroy_by_rcu);
4572 static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4574 return sprintf(buf, "%d\n", s->reserved);
4576 SLAB_ATTR_RO(reserved);
4578 #ifdef CONFIG_SLUB_DEBUG
4579 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4581 return show_slab_objects(s, buf, SO_ALL);
4583 SLAB_ATTR_RO(slabs);
4585 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4587 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4589 SLAB_ATTR_RO(total_objects);
4591 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4593 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4596 static ssize_t sanity_checks_store(struct kmem_cache *s,
4597 const char *buf, size_t length)
4599 s->flags &= ~SLAB_DEBUG_FREE;
4600 if (buf[0] == '1') {
4601 s->flags &= ~__CMPXCHG_DOUBLE;
4602 s->flags |= SLAB_DEBUG_FREE;
4606 SLAB_ATTR(sanity_checks);
4608 static ssize_t trace_show(struct kmem_cache *s, char *buf)
4610 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4613 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4616 s->flags &= ~SLAB_TRACE;
4617 if (buf[0] == '1') {
4618 s->flags &= ~__CMPXCHG_DOUBLE;
4619 s->flags |= SLAB_TRACE;
4625 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4627 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4630 static ssize_t red_zone_store(struct kmem_cache *s,
4631 const char *buf, size_t length)
4633 if (any_slab_objects(s))
4636 s->flags &= ~SLAB_RED_ZONE;
4637 if (buf[0] == '1') {
4638 s->flags &= ~__CMPXCHG_DOUBLE;
4639 s->flags |= SLAB_RED_ZONE;
4641 calculate_sizes(s, -1);
4644 SLAB_ATTR(red_zone);
4646 static ssize_t poison_show(struct kmem_cache *s, char *buf)
4648 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4651 static ssize_t poison_store(struct kmem_cache *s,
4652 const char *buf, size_t length)
4654 if (any_slab_objects(s))
4657 s->flags &= ~SLAB_POISON;
4658 if (buf[0] == '1') {
4659 s->flags &= ~__CMPXCHG_DOUBLE;
4660 s->flags |= SLAB_POISON;
4662 calculate_sizes(s, -1);
4667 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4669 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4672 static ssize_t store_user_store(struct kmem_cache *s,
4673 const char *buf, size_t length)
4675 if (any_slab_objects(s))
4678 s->flags &= ~SLAB_STORE_USER;
4679 if (buf[0] == '1') {
4680 s->flags &= ~__CMPXCHG_DOUBLE;
4681 s->flags |= SLAB_STORE_USER;
4683 calculate_sizes(s, -1);
4686 SLAB_ATTR(store_user);
4688 static ssize_t validate_show(struct kmem_cache *s, char *buf)
4693 static ssize_t validate_store(struct kmem_cache *s,
4694 const char *buf, size_t length)
4698 if (buf[0] == '1') {
4699 ret = validate_slab_cache(s);
4705 SLAB_ATTR(validate);
4707 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4709 if (!(s->flags & SLAB_STORE_USER))
4711 return list_locations(s, buf, TRACK_ALLOC);
4713 SLAB_ATTR_RO(alloc_calls);
4715 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4717 if (!(s->flags & SLAB_STORE_USER))
4719 return list_locations(s, buf, TRACK_FREE);
4721 SLAB_ATTR_RO(free_calls);
4722 #endif /* CONFIG_SLUB_DEBUG */
4724 #ifdef CONFIG_FAILSLAB
4725 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4727 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4730 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4733 s->flags &= ~SLAB_FAILSLAB;
4735 s->flags |= SLAB_FAILSLAB;
4738 SLAB_ATTR(failslab);
4741 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4746 static ssize_t shrink_store(struct kmem_cache *s,
4747 const char *buf, size_t length)
4749 if (buf[0] == '1') {
4750 int rc = kmem_cache_shrink(s);
4761 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4763 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4766 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4767 const char *buf, size_t length)
4769 unsigned long ratio;
4772 err = strict_strtoul(buf, 10, &ratio);
4777 s->remote_node_defrag_ratio = ratio * 10;
4781 SLAB_ATTR(remote_node_defrag_ratio);
4784 #ifdef CONFIG_SLUB_STATS
4785 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4787 unsigned long sum = 0;
4790 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4795 for_each_online_cpu(cpu) {
4796 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
4802 len = sprintf(buf, "%lu", sum);
4805 for_each_online_cpu(cpu) {
4806 if (data[cpu] && len < PAGE_SIZE - 20)
4807 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4811 return len + sprintf(buf + len, "\n");
4814 static void clear_stat(struct kmem_cache *s, enum stat_item si)
4818 for_each_online_cpu(cpu)
4819 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
4822 #define STAT_ATTR(si, text) \
4823 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4825 return show_stat(s, buf, si); \
4827 static ssize_t text##_store(struct kmem_cache *s, \
4828 const char *buf, size_t length) \
4830 if (buf[0] != '0') \
4832 clear_stat(s, si); \
4837 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4838 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4839 STAT_ATTR(FREE_FASTPATH, free_fastpath);
4840 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4841 STAT_ATTR(FREE_FROZEN, free_frozen);
4842 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4843 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4844 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4845 STAT_ATTR(ALLOC_SLAB, alloc_slab);
4846 STAT_ATTR(ALLOC_REFILL, alloc_refill);
4847 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
4848 STAT_ATTR(FREE_SLAB, free_slab);
4849 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4850 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4851 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4852 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4853 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4854 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4855 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
4856 STAT_ATTR(ORDER_FALLBACK, order_fallback);
4857 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
4858 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
4859 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
4860 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
4861 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
4862 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
4865 static struct attribute *slab_attrs[] = {
4866 &slab_size_attr.attr,
4867 &object_size_attr.attr,
4868 &objs_per_slab_attr.attr,
4870 &min_partial_attr.attr,
4871 &cpu_partial_attr.attr,
4873 &objects_partial_attr.attr,
4875 &cpu_slabs_attr.attr,
4879 &hwcache_align_attr.attr,
4880 &reclaim_account_attr.attr,
4881 &destroy_by_rcu_attr.attr,
4883 &reserved_attr.attr,
4884 &slabs_cpu_partial_attr.attr,
4885 #ifdef CONFIG_SLUB_DEBUG
4886 &total_objects_attr.attr,
4888 &sanity_checks_attr.attr,
4890 &red_zone_attr.attr,
4892 &store_user_attr.attr,
4893 &validate_attr.attr,
4894 &alloc_calls_attr.attr,
4895 &free_calls_attr.attr,
4897 #ifdef CONFIG_ZONE_DMA
4898 &cache_dma_attr.attr,
4901 &remote_node_defrag_ratio_attr.attr,
4903 #ifdef CONFIG_SLUB_STATS
4904 &alloc_fastpath_attr.attr,
4905 &alloc_slowpath_attr.attr,
4906 &free_fastpath_attr.attr,
4907 &free_slowpath_attr.attr,
4908 &free_frozen_attr.attr,
4909 &free_add_partial_attr.attr,
4910 &free_remove_partial_attr.attr,
4911 &alloc_from_partial_attr.attr,
4912 &alloc_slab_attr.attr,
4913 &alloc_refill_attr.attr,
4914 &alloc_node_mismatch_attr.attr,
4915 &free_slab_attr.attr,
4916 &cpuslab_flush_attr.attr,
4917 &deactivate_full_attr.attr,
4918 &deactivate_empty_attr.attr,
4919 &deactivate_to_head_attr.attr,
4920 &deactivate_to_tail_attr.attr,
4921 &deactivate_remote_frees_attr.attr,
4922 &deactivate_bypass_attr.attr,
4923 &order_fallback_attr.attr,
4924 &cmpxchg_double_fail_attr.attr,
4925 &cmpxchg_double_cpu_fail_attr.attr,
4926 &cpu_partial_alloc_attr.attr,
4927 &cpu_partial_free_attr.attr,
4928 &cpu_partial_node_attr.attr,
4929 &cpu_partial_drain_attr.attr,
4931 #ifdef CONFIG_FAILSLAB
4932 &failslab_attr.attr,
4938 static struct attribute_group slab_attr_group = {
4939 .attrs = slab_attrs,
4942 static ssize_t slab_attr_show(struct kobject *kobj,
4943 struct attribute *attr,
4946 struct slab_attribute *attribute;
4947 struct kmem_cache *s;
4950 attribute = to_slab_attr(attr);
4953 if (!attribute->show)
4956 err = attribute->show(s, buf);
4961 static ssize_t slab_attr_store(struct kobject *kobj,
4962 struct attribute *attr,
4963 const char *buf, size_t len)
4965 struct slab_attribute *attribute;
4966 struct kmem_cache *s;
4969 attribute = to_slab_attr(attr);
4972 if (!attribute->store)
4975 err = attribute->store(s, buf, len);
4976 #ifdef CONFIG_MEMCG_KMEM
4977 if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
4980 mutex_lock(&slab_mutex);
4981 if (s->max_attr_size < len)
4982 s->max_attr_size = len;
4985 * This is a best effort propagation, so this function's return
4986 * value will be determined by the parent cache only. This is
4987 * basically because not all attributes will have a well
4988 * defined semantics for rollbacks - most of the actions will
4989 * have permanent effects.
4991 * Returning the error value of any of the children that fail
4992 * is not 100 % defined, in the sense that users seeing the
4993 * error code won't be able to know anything about the state of
4996 * Only returning the error code for the parent cache at least
4997 * has well defined semantics. The cache being written to
4998 * directly either failed or succeeded, in which case we loop
4999 * through the descendants with best-effort propagation.
5001 for_each_memcg_cache_index(i) {
5002 struct kmem_cache *c = cache_from_memcg(s, i);
5004 attribute->store(c, buf, len);
5006 mutex_unlock(&slab_mutex);
5012 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5014 #ifdef CONFIG_MEMCG_KMEM
5016 char *buffer = NULL;
5018 if (!is_root_cache(s))
5022 * This mean this cache had no attribute written. Therefore, no point
5023 * in copying default values around
5025 if (!s->max_attr_size)
5028 for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5031 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5033 if (!attr || !attr->store || !attr->show)
5037 * It is really bad that we have to allocate here, so we will
5038 * do it only as a fallback. If we actually allocate, though,
5039 * we can just use the allocated buffer until the end.
5041 * Most of the slub attributes will tend to be very small in
5042 * size, but sysfs allows buffers up to a page, so they can
5043 * theoretically happen.
5047 else if (s->max_attr_size < ARRAY_SIZE(mbuf))
5050 buffer = (char *) get_zeroed_page(GFP_KERNEL);
5051 if (WARN_ON(!buffer))
5056 attr->show(s->memcg_params->root_cache, buf);
5057 attr->store(s, buf, strlen(buf));
5061 free_page((unsigned long)buffer);
5065 static const struct sysfs_ops slab_sysfs_ops = {
5066 .show = slab_attr_show,
5067 .store = slab_attr_store,
5070 static struct kobj_type slab_ktype = {
5071 .sysfs_ops = &slab_sysfs_ops,
5074 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5076 struct kobj_type *ktype = get_ktype(kobj);
5078 if (ktype == &slab_ktype)
5083 static const struct kset_uevent_ops slab_uevent_ops = {
5084 .filter = uevent_filter,
5087 static struct kset *slab_kset;
5089 #define ID_STR_LENGTH 64
5091 /* Create a unique string id for a slab cache:
5093 * Format :[flags-]size
5095 static char *create_unique_id(struct kmem_cache *s)
5097 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5104 * First flags affecting slabcache operations. We will only
5105 * get here for aliasable slabs so we do not need to support
5106 * too many flags. The flags here must cover all flags that
5107 * are matched during merging to guarantee that the id is
5110 if (s->flags & SLAB_CACHE_DMA)
5112 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5114 if (s->flags & SLAB_DEBUG_FREE)
5116 if (!(s->flags & SLAB_NOTRACK))
5120 p += sprintf(p, "%07d", s->size);
5122 #ifdef CONFIG_MEMCG_KMEM
5123 if (!is_root_cache(s))
5124 p += sprintf(p, "-%08d", memcg_cache_id(s->memcg_params->memcg));
5127 BUG_ON(p > name + ID_STR_LENGTH - 1);
5131 static int sysfs_slab_add(struct kmem_cache *s)
5135 int unmergeable = slab_unmergeable(s);
5139 * Slabcache can never be merged so we can use the name proper.
5140 * This is typically the case for debug situations. In that
5141 * case we can catch duplicate names easily.
5143 sysfs_remove_link(&slab_kset->kobj, s->name);
5147 * Create a unique name for the slab as a target
5150 name = create_unique_id(s);
5153 s->kobj.kset = slab_kset;
5154 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5156 kobject_put(&s->kobj);
5160 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5162 kobject_del(&s->kobj);
5163 kobject_put(&s->kobj);
5166 kobject_uevent(&s->kobj, KOBJ_ADD);
5168 /* Setup first alias */
5169 sysfs_slab_alias(s, s->name);
5175 static void sysfs_slab_remove(struct kmem_cache *s)
5177 if (slab_state < FULL)
5179 * Sysfs has not been setup yet so no need to remove the
5184 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5185 kobject_del(&s->kobj);
5186 kobject_put(&s->kobj);
5190 * Need to buffer aliases during bootup until sysfs becomes
5191 * available lest we lose that information.
5193 struct saved_alias {
5194 struct kmem_cache *s;
5196 struct saved_alias *next;
5199 static struct saved_alias *alias_list;
5201 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5203 struct saved_alias *al;
5205 if (slab_state == FULL) {
5207 * If we have a leftover link then remove it.
5209 sysfs_remove_link(&slab_kset->kobj, name);
5210 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5213 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5219 al->next = alias_list;
5224 static int __init slab_sysfs_init(void)
5226 struct kmem_cache *s;
5229 mutex_lock(&slab_mutex);
5231 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5233 mutex_unlock(&slab_mutex);
5234 printk(KERN_ERR "Cannot register slab subsystem.\n");
5240 list_for_each_entry(s, &slab_caches, list) {
5241 err = sysfs_slab_add(s);
5243 printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5244 " to sysfs\n", s->name);
5247 while (alias_list) {
5248 struct saved_alias *al = alias_list;
5250 alias_list = alias_list->next;
5251 err = sysfs_slab_alias(al->s, al->name);
5253 printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5254 " %s to sysfs\n", al->name);
5258 mutex_unlock(&slab_mutex);
5263 __initcall(slab_sysfs_init);
5264 #endif /* CONFIG_SYSFS */
5267 * The /proc/slabinfo ABI
5269 #ifdef CONFIG_SLABINFO
5270 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5272 unsigned long nr_slabs = 0;
5273 unsigned long nr_objs = 0;
5274 unsigned long nr_free = 0;
5277 for_each_online_node(node) {
5278 struct kmem_cache_node *n = get_node(s, node);
5283 nr_slabs += node_nr_slabs(n);
5284 nr_objs += node_nr_objs(n);
5285 nr_free += count_partial(n, count_free);
5288 sinfo->active_objs = nr_objs - nr_free;
5289 sinfo->num_objs = nr_objs;
5290 sinfo->active_slabs = nr_slabs;
5291 sinfo->num_slabs = nr_slabs;
5292 sinfo->objects_per_slab = oo_objects(s->oo);
5293 sinfo->cache_order = oo_order(s->oo);
5296 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5300 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5301 size_t count, loff_t *ppos)
5305 #endif /* CONFIG_SLABINFO */