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/notifier.h>
22 #include <linux/seq_file.h>
23 #include <linux/kasan.h>
24 #include <linux/kmemcheck.h>
25 #include <linux/cpu.h>
26 #include <linux/cpuset.h>
27 #include <linux/mempolicy.h>
28 #include <linux/ctype.h>
29 #include <linux/debugobjects.h>
30 #include <linux/kallsyms.h>
31 #include <linux/memory.h>
32 #include <linux/math64.h>
33 #include <linux/fault-inject.h>
34 #include <linux/stacktrace.h>
35 #include <linux/prefetch.h>
36 #include <linux/memcontrol.h>
38 #include <trace/events/kmem.h>
44 * 1. slab_mutex (Global Mutex)
46 * 3. slab_lock(page) (Only on some arches and for debugging)
50 * The role of the slab_mutex is to protect the list of all the slabs
51 * and to synchronize major metadata changes to slab cache structures.
53 * The slab_lock is only used for debugging and on arches that do not
54 * have the ability to do a cmpxchg_double. It only protects the second
55 * double word in the page struct. Meaning
56 * A. page->freelist -> List of object free in a page
57 * B. page->counters -> Counters of objects
58 * C. page->frozen -> frozen state
60 * If a slab is frozen then it is exempt from list management. It is not
61 * on any list. The processor that froze the slab is the one who can
62 * perform list operations on the page. Other processors may put objects
63 * onto the freelist but the processor that froze the slab is the only
64 * one that can retrieve the objects from the page's freelist.
66 * The list_lock protects the partial and full list on each node and
67 * the partial slab counter. If taken then no new slabs may be added or
68 * removed from the lists nor make the number of partial slabs be modified.
69 * (Note that the total number of slabs is an atomic value that may be
70 * modified without taking the list lock).
72 * The list_lock is a centralized lock and thus we avoid taking it as
73 * much as possible. As long as SLUB does not have to handle partial
74 * slabs, operations can continue without any centralized lock. F.e.
75 * allocating a long series of objects that fill up slabs does not require
77 * Interrupts are disabled during allocation and deallocation in order to
78 * make the slab allocator safe to use in the context of an irq. In addition
79 * interrupts are disabled to ensure that the processor does not change
80 * while handling per_cpu slabs, due to kernel preemption.
82 * SLUB assigns one slab for allocation to each processor.
83 * Allocations only occur from these slabs called cpu slabs.
85 * Slabs with free elements are kept on a partial list and during regular
86 * operations no list for full slabs is used. If an object in a full slab is
87 * freed then the slab will show up again on the partial lists.
88 * We track full slabs for debugging purposes though because otherwise we
89 * cannot scan all objects.
91 * Slabs are freed when they become empty. Teardown and setup is
92 * minimal so we rely on the page allocators per cpu caches for
93 * fast frees and allocs.
95 * Overloading of page flags that are otherwise used for LRU management.
97 * PageActive The slab is frozen and exempt from list processing.
98 * This means that the slab is dedicated to a purpose
99 * such as satisfying allocations for a specific
100 * processor. Objects may be freed in the slab while
101 * it is frozen but slab_free will then skip the usual
102 * list operations. It is up to the processor holding
103 * the slab to integrate the slab into the slab lists
104 * when the slab is no longer needed.
106 * One use of this flag is to mark slabs that are
107 * used for allocations. Then such a slab becomes a cpu
108 * slab. The cpu slab may be equipped with an additional
109 * freelist that allows lockless access to
110 * free objects in addition to the regular freelist
111 * that requires the slab lock.
113 * PageError Slab requires special handling due to debug
114 * options set. This moves slab handling out of
115 * the fast path and disables lockless freelists.
118 static inline int kmem_cache_debug(struct kmem_cache *s)
120 #ifdef CONFIG_SLUB_DEBUG
121 return unlikely(s->flags & SLAB_DEBUG_FLAGS);
127 static inline void *fixup_red_left(struct kmem_cache *s, void *p)
129 if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)
130 p += s->red_left_pad;
135 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
137 #ifdef CONFIG_SLUB_CPU_PARTIAL
138 return !kmem_cache_debug(s);
145 * Issues still to be resolved:
147 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
149 * - Variable sizing of the per node arrays
152 /* Enable to test recovery from slab corruption on boot */
153 #undef SLUB_RESILIENCY_TEST
155 /* Enable to log cmpxchg failures */
156 #undef SLUB_DEBUG_CMPXCHG
159 * Mininum number of partial slabs. These will be left on the partial
160 * lists even if they are empty. kmem_cache_shrink may reclaim them.
162 #define MIN_PARTIAL 5
165 * Maximum number of desirable partial slabs.
166 * The existence of more partial slabs makes kmem_cache_shrink
167 * sort the partial list by the number of objects in use.
169 #define MAX_PARTIAL 10
171 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
172 SLAB_POISON | SLAB_STORE_USER)
175 * These debug flags cannot use CMPXCHG because there might be consistency
176 * issues when checking or reading debug information
178 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
183 * Debugging flags that require metadata to be stored in the slab. These get
184 * disabled when slub_debug=O is used and a cache's min order increases with
187 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
190 #define OO_MASK ((1 << OO_SHIFT) - 1)
191 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
193 /* Internal SLUB flags */
194 #define __OBJECT_POISON 0x80000000UL /* Poison object */
195 #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
198 static struct notifier_block slab_notifier;
202 * Tracking user of a slab.
204 #define TRACK_ADDRS_COUNT 16
206 unsigned long addr; /* Called from address */
207 #ifdef CONFIG_STACKTRACE
208 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
210 int cpu; /* Was running on cpu */
211 int pid; /* Pid context */
212 unsigned long when; /* When did the operation occur */
215 enum track_item { TRACK_ALLOC, TRACK_FREE };
218 static int sysfs_slab_add(struct kmem_cache *);
219 static int sysfs_slab_alias(struct kmem_cache *, const char *);
220 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
222 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
223 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
225 static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
228 static inline void stat(const struct kmem_cache *s, enum stat_item si)
230 #ifdef CONFIG_SLUB_STATS
232 * The rmw is racy on a preemptible kernel but this is acceptable, so
233 * avoid this_cpu_add()'s irq-disable overhead.
235 raw_cpu_inc(s->cpu_slab->stat[si]);
239 /********************************************************************
240 * Core slab cache functions
241 *******************************************************************/
243 static inline void *get_freepointer(struct kmem_cache *s, void *object)
245 return *(void **)(object + s->offset);
248 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
250 prefetch(object + s->offset);
253 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
257 if (!debug_pagealloc_enabled())
258 return get_freepointer(s, object);
260 probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
264 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
266 *(void **)(object + s->offset) = fp;
269 /* Loop over all objects in a slab */
270 #define for_each_object(__p, __s, __addr, __objects) \
271 for (__p = fixup_red_left(__s, __addr); \
272 __p < (__addr) + (__objects) * (__s)->size; \
275 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
276 for (__p = fixup_red_left(__s, __addr), __idx = 1; \
277 __idx <= __objects; \
278 __p += (__s)->size, __idx++)
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 int order_objects(int order, unsigned long size, int reserved)
288 return ((PAGE_SIZE << order) - reserved) / size;
291 static inline struct kmem_cache_order_objects oo_make(int order,
292 unsigned long size, int reserved)
294 struct kmem_cache_order_objects x = {
295 (order << OO_SHIFT) + order_objects(order, size, reserved)
301 static inline int oo_order(struct kmem_cache_order_objects x)
303 return x.x >> OO_SHIFT;
306 static inline int oo_objects(struct kmem_cache_order_objects x)
308 return x.x & OO_MASK;
312 * Per slab locking using the pagelock
314 static __always_inline void slab_lock(struct page *page)
316 VM_BUG_ON_PAGE(PageTail(page), page);
317 bit_spin_lock(PG_locked, &page->flags);
320 static __always_inline void slab_unlock(struct page *page)
322 VM_BUG_ON_PAGE(PageTail(page), page);
323 __bit_spin_unlock(PG_locked, &page->flags);
326 static inline void set_page_slub_counters(struct page *page, unsigned long counters_new)
329 tmp.counters = counters_new;
331 * page->counters can cover frozen/inuse/objects as well
332 * as page->_refcount. If we assign to ->counters directly
333 * we run the risk of losing updates to page->_refcount, so
334 * be careful and only assign to the fields we need.
336 page->frozen = tmp.frozen;
337 page->inuse = tmp.inuse;
338 page->objects = tmp.objects;
341 /* Interrupts must be disabled (for the fallback code to work right) */
342 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
343 void *freelist_old, unsigned long counters_old,
344 void *freelist_new, unsigned long counters_new,
347 VM_BUG_ON(!irqs_disabled());
348 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
349 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
350 if (s->flags & __CMPXCHG_DOUBLE) {
351 if (cmpxchg_double(&page->freelist, &page->counters,
352 freelist_old, counters_old,
353 freelist_new, counters_new))
359 if (page->freelist == freelist_old &&
360 page->counters == counters_old) {
361 page->freelist = freelist_new;
362 set_page_slub_counters(page, counters_new);
370 stat(s, CMPXCHG_DOUBLE_FAIL);
372 #ifdef SLUB_DEBUG_CMPXCHG
373 pr_info("%s %s: cmpxchg double redo ", n, s->name);
379 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
380 void *freelist_old, unsigned long counters_old,
381 void *freelist_new, unsigned long counters_new,
384 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
385 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
386 if (s->flags & __CMPXCHG_DOUBLE) {
387 if (cmpxchg_double(&page->freelist, &page->counters,
388 freelist_old, counters_old,
389 freelist_new, counters_new))
396 local_irq_save(flags);
398 if (page->freelist == freelist_old &&
399 page->counters == counters_old) {
400 page->freelist = freelist_new;
401 set_page_slub_counters(page, counters_new);
403 local_irq_restore(flags);
407 local_irq_restore(flags);
411 stat(s, CMPXCHG_DOUBLE_FAIL);
413 #ifdef SLUB_DEBUG_CMPXCHG
414 pr_info("%s %s: cmpxchg double redo ", n, s->name);
420 #ifdef CONFIG_SLUB_DEBUG
422 * Determine a map of object in use on a page.
424 * Node listlock must be held to guarantee that the page does
425 * not vanish from under us.
427 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
430 void *addr = page_address(page);
432 for (p = page->freelist; p; p = get_freepointer(s, p))
433 set_bit(slab_index(p, s, addr), map);
436 static inline int size_from_object(struct kmem_cache *s)
438 if (s->flags & SLAB_RED_ZONE)
439 return s->size - s->red_left_pad;
444 static inline void *restore_red_left(struct kmem_cache *s, void *p)
446 if (s->flags & SLAB_RED_ZONE)
447 p -= s->red_left_pad;
455 #if defined(CONFIG_SLUB_DEBUG_ON)
456 static int slub_debug = DEBUG_DEFAULT_FLAGS;
457 #elif defined(CONFIG_KASAN)
458 static int slub_debug = SLAB_STORE_USER;
460 static int slub_debug;
463 static char *slub_debug_slabs;
464 static int disable_higher_order_debug;
467 * slub is about to manipulate internal object metadata. This memory lies
468 * outside the range of the allocated object, so accessing it would normally
469 * be reported by kasan as a bounds error. metadata_access_enable() is used
470 * to tell kasan that these accesses are OK.
472 static inline void metadata_access_enable(void)
474 kasan_disable_current();
477 static inline void metadata_access_disable(void)
479 kasan_enable_current();
486 /* Verify that a pointer has an address that is valid within a slab page */
487 static inline int check_valid_pointer(struct kmem_cache *s,
488 struct page *page, void *object)
495 base = page_address(page);
496 object = restore_red_left(s, object);
497 if (object < base || object >= base + page->objects * s->size ||
498 (object - base) % s->size) {
505 static void print_section(char *text, u8 *addr, unsigned int length)
507 metadata_access_enable();
508 print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
510 metadata_access_disable();
513 static struct track *get_track(struct kmem_cache *s, void *object,
514 enum track_item alloc)
519 p = object + s->offset + sizeof(void *);
521 p = object + s->inuse;
526 static void set_track(struct kmem_cache *s, void *object,
527 enum track_item alloc, unsigned long addr)
529 struct track *p = get_track(s, object, alloc);
532 #ifdef CONFIG_STACKTRACE
533 struct stack_trace trace;
536 trace.nr_entries = 0;
537 trace.max_entries = TRACK_ADDRS_COUNT;
538 trace.entries = p->addrs;
540 metadata_access_enable();
541 save_stack_trace(&trace);
542 metadata_access_disable();
544 /* See rant in lockdep.c */
545 if (trace.nr_entries != 0 &&
546 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
549 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
553 p->cpu = smp_processor_id();
554 p->pid = current->pid;
557 memset(p, 0, sizeof(struct track));
560 static void init_tracking(struct kmem_cache *s, void *object)
562 if (!(s->flags & SLAB_STORE_USER))
565 set_track(s, object, TRACK_FREE, 0UL);
566 set_track(s, object, TRACK_ALLOC, 0UL);
569 static void print_track(const char *s, struct track *t)
574 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
575 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
576 #ifdef CONFIG_STACKTRACE
579 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
581 pr_err("\t%pS\n", (void *)t->addrs[i]);
588 static void print_tracking(struct kmem_cache *s, void *object)
590 if (!(s->flags & SLAB_STORE_USER))
593 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
594 print_track("Freed", get_track(s, object, TRACK_FREE));
597 static void print_page_info(struct page *page)
599 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
600 page, page->objects, page->inuse, page->freelist, page->flags);
604 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
606 struct va_format vaf;
612 pr_err("=============================================================================\n");
613 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
614 pr_err("-----------------------------------------------------------------------------\n\n");
616 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
620 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
622 struct va_format vaf;
628 pr_err("FIX %s: %pV\n", s->name, &vaf);
632 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
634 unsigned int off; /* Offset of last byte */
635 u8 *addr = page_address(page);
637 print_tracking(s, p);
639 print_page_info(page);
641 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
642 p, p - addr, get_freepointer(s, p));
644 if (s->flags & SLAB_RED_ZONE)
645 print_section("Redzone ", p - s->red_left_pad, s->red_left_pad);
646 else if (p > addr + 16)
647 print_section("Bytes b4 ", p - 16, 16);
649 print_section("Object ", p, min_t(unsigned long, s->object_size,
651 if (s->flags & SLAB_RED_ZONE)
652 print_section("Redzone ", p + s->object_size,
653 s->inuse - s->object_size);
656 off = s->offset + sizeof(void *);
660 if (s->flags & SLAB_STORE_USER)
661 off += 2 * sizeof(struct track);
663 if (off != size_from_object(s))
664 /* Beginning of the filler is the free pointer */
665 print_section("Padding ", p + off, size_from_object(s) - off);
670 void object_err(struct kmem_cache *s, struct page *page,
671 u8 *object, char *reason)
673 slab_bug(s, "%s", reason);
674 print_trailer(s, page, object);
677 static void slab_err(struct kmem_cache *s, struct page *page,
678 const char *fmt, ...)
684 vsnprintf(buf, sizeof(buf), fmt, args);
686 slab_bug(s, "%s", buf);
687 print_page_info(page);
691 static void init_object(struct kmem_cache *s, void *object, u8 val)
695 if (s->flags & SLAB_RED_ZONE)
696 memset(p - s->red_left_pad, val, s->red_left_pad);
698 if (s->flags & __OBJECT_POISON) {
699 memset(p, POISON_FREE, s->object_size - 1);
700 p[s->object_size - 1] = POISON_END;
703 if (s->flags & SLAB_RED_ZONE)
704 memset(p + s->object_size, val, s->inuse - s->object_size);
707 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
708 void *from, void *to)
710 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
711 memset(from, data, to - from);
714 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
715 u8 *object, char *what,
716 u8 *start, unsigned int value, unsigned int bytes)
721 metadata_access_enable();
722 fault = memchr_inv(start, value, bytes);
723 metadata_access_disable();
728 while (end > fault && end[-1] == value)
731 slab_bug(s, "%s overwritten", what);
732 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
733 fault, end - 1, fault[0], value);
734 print_trailer(s, page, object);
736 restore_bytes(s, what, value, fault, end);
744 * Bytes of the object to be managed.
745 * If the freepointer may overlay the object then the free
746 * pointer is the first word of the object.
748 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
751 * object + s->object_size
752 * Padding to reach word boundary. This is also used for Redzoning.
753 * Padding is extended by another word if Redzoning is enabled and
754 * object_size == inuse.
756 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
757 * 0xcc (RED_ACTIVE) for objects in use.
760 * Meta data starts here.
762 * A. Free pointer (if we cannot overwrite object on free)
763 * B. Tracking data for SLAB_STORE_USER
764 * C. Padding to reach required alignment boundary or at mininum
765 * one word if debugging is on to be able to detect writes
766 * before the word boundary.
768 * Padding is done using 0x5a (POISON_INUSE)
771 * Nothing is used beyond s->size.
773 * If slabcaches are merged then the object_size and inuse boundaries are mostly
774 * ignored. And therefore no slab options that rely on these boundaries
775 * may be used with merged slabcaches.
778 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
780 unsigned long off = s->inuse; /* The end of info */
783 /* Freepointer is placed after the object. */
784 off += sizeof(void *);
786 if (s->flags & SLAB_STORE_USER)
787 /* We also have user information there */
788 off += 2 * sizeof(struct track);
790 if (size_from_object(s) == off)
793 return check_bytes_and_report(s, page, p, "Object padding",
794 p + off, POISON_INUSE, size_from_object(s) - off);
797 /* Check the pad bytes at the end of a slab page */
798 static int slab_pad_check(struct kmem_cache *s, struct page *page)
806 if (!(s->flags & SLAB_POISON))
809 start = page_address(page);
810 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
811 end = start + length;
812 remainder = length % s->size;
816 metadata_access_enable();
817 fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
818 metadata_access_disable();
821 while (end > fault && end[-1] == POISON_INUSE)
824 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
825 print_section("Padding ", end - remainder, remainder);
827 restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
831 static int check_object(struct kmem_cache *s, struct page *page,
832 void *object, u8 val)
835 u8 *endobject = object + s->object_size;
837 if (s->flags & SLAB_RED_ZONE) {
838 if (!check_bytes_and_report(s, page, object, "Redzone",
839 object - s->red_left_pad, val, s->red_left_pad))
842 if (!check_bytes_and_report(s, page, object, "Redzone",
843 endobject, val, s->inuse - s->object_size))
846 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
847 check_bytes_and_report(s, page, p, "Alignment padding",
848 endobject, POISON_INUSE,
849 s->inuse - s->object_size);
853 if (s->flags & SLAB_POISON) {
854 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
855 (!check_bytes_and_report(s, page, p, "Poison", p,
856 POISON_FREE, s->object_size - 1) ||
857 !check_bytes_and_report(s, page, p, "Poison",
858 p + s->object_size - 1, POISON_END, 1)))
861 * check_pad_bytes cleans up on its own.
863 check_pad_bytes(s, page, p);
866 if (!s->offset && val == SLUB_RED_ACTIVE)
868 * Object and freepointer overlap. Cannot check
869 * freepointer while object is allocated.
873 /* Check free pointer validity */
874 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
875 object_err(s, page, p, "Freepointer corrupt");
877 * No choice but to zap it and thus lose the remainder
878 * of the free objects in this slab. May cause
879 * another error because the object count is now wrong.
881 set_freepointer(s, p, NULL);
887 static int check_slab(struct kmem_cache *s, struct page *page)
891 VM_BUG_ON(!irqs_disabled());
893 if (!PageSlab(page)) {
894 slab_err(s, page, "Not a valid slab page");
898 maxobj = order_objects(compound_order(page), s->size, s->reserved);
899 if (page->objects > maxobj) {
900 slab_err(s, page, "objects %u > max %u",
901 page->objects, maxobj);
904 if (page->inuse > page->objects) {
905 slab_err(s, page, "inuse %u > max %u",
906 page->inuse, page->objects);
909 /* Slab_pad_check fixes things up after itself */
910 slab_pad_check(s, page);
915 * Determine if a certain object on a page is on the freelist. Must hold the
916 * slab lock to guarantee that the chains are in a consistent state.
918 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
926 while (fp && nr <= page->objects) {
929 if (!check_valid_pointer(s, page, fp)) {
931 object_err(s, page, object,
932 "Freechain corrupt");
933 set_freepointer(s, object, NULL);
935 slab_err(s, page, "Freepointer corrupt");
936 page->freelist = NULL;
937 page->inuse = page->objects;
938 slab_fix(s, "Freelist cleared");
944 fp = get_freepointer(s, object);
948 max_objects = order_objects(compound_order(page), s->size, s->reserved);
949 if (max_objects > MAX_OBJS_PER_PAGE)
950 max_objects = MAX_OBJS_PER_PAGE;
952 if (page->objects != max_objects) {
953 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
954 page->objects, max_objects);
955 page->objects = max_objects;
956 slab_fix(s, "Number of objects adjusted.");
958 if (page->inuse != page->objects - nr) {
959 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
960 page->inuse, page->objects - nr);
961 page->inuse = page->objects - nr;
962 slab_fix(s, "Object count adjusted.");
964 return search == NULL;
967 static void trace(struct kmem_cache *s, struct page *page, void *object,
970 if (s->flags & SLAB_TRACE) {
971 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
973 alloc ? "alloc" : "free",
978 print_section("Object ", (void *)object,
986 * Tracking of fully allocated slabs for debugging purposes.
988 static void add_full(struct kmem_cache *s,
989 struct kmem_cache_node *n, struct page *page)
991 if (!(s->flags & SLAB_STORE_USER))
994 lockdep_assert_held(&n->list_lock);
995 list_add(&page->lru, &n->full);
998 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1000 if (!(s->flags & SLAB_STORE_USER))
1003 lockdep_assert_held(&n->list_lock);
1004 list_del(&page->lru);
1007 /* Tracking of the number of slabs for debugging purposes */
1008 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1010 struct kmem_cache_node *n = get_node(s, node);
1012 return atomic_long_read(&n->nr_slabs);
1015 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1017 return atomic_long_read(&n->nr_slabs);
1020 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1022 struct kmem_cache_node *n = get_node(s, node);
1025 * May be called early in order to allocate a slab for the
1026 * kmem_cache_node structure. Solve the chicken-egg
1027 * dilemma by deferring the increment of the count during
1028 * bootstrap (see early_kmem_cache_node_alloc).
1031 atomic_long_inc(&n->nr_slabs);
1032 atomic_long_add(objects, &n->total_objects);
1035 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1037 struct kmem_cache_node *n = get_node(s, node);
1039 atomic_long_dec(&n->nr_slabs);
1040 atomic_long_sub(objects, &n->total_objects);
1043 /* Object debug checks for alloc/free paths */
1044 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1047 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1050 init_object(s, object, SLUB_RED_INACTIVE);
1051 init_tracking(s, object);
1054 static inline int alloc_consistency_checks(struct kmem_cache *s,
1056 void *object, unsigned long addr)
1058 if (!check_slab(s, page))
1061 if (!check_valid_pointer(s, page, object)) {
1062 object_err(s, page, object, "Freelist Pointer check fails");
1066 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1072 static noinline int alloc_debug_processing(struct kmem_cache *s,
1074 void *object, unsigned long addr)
1076 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1077 if (!alloc_consistency_checks(s, page, object, addr))
1081 /* Success perform special debug activities for allocs */
1082 if (s->flags & SLAB_STORE_USER)
1083 set_track(s, object, TRACK_ALLOC, addr);
1084 trace(s, page, object, 1);
1085 init_object(s, object, SLUB_RED_ACTIVE);
1089 if (PageSlab(page)) {
1091 * If this is a slab page then lets do the best we can
1092 * to avoid issues in the future. Marking all objects
1093 * as used avoids touching the remaining objects.
1095 slab_fix(s, "Marking all objects used");
1096 page->inuse = page->objects;
1097 page->freelist = NULL;
1102 static inline int free_consistency_checks(struct kmem_cache *s,
1103 struct page *page, void *object, unsigned long addr)
1105 if (!check_valid_pointer(s, page, object)) {
1106 slab_err(s, page, "Invalid object pointer 0x%p", object);
1110 if (on_freelist(s, page, object)) {
1111 object_err(s, page, object, "Object already free");
1115 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1118 if (unlikely(s != page->slab_cache)) {
1119 if (!PageSlab(page)) {
1120 slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1122 } else if (!page->slab_cache) {
1123 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1127 object_err(s, page, object,
1128 "page slab pointer corrupt.");
1134 /* Supports checking bulk free of a constructed freelist */
1135 static noinline int free_debug_processing(
1136 struct kmem_cache *s, struct page *page,
1137 void *head, void *tail, int bulk_cnt,
1140 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1141 void *object = head;
1143 unsigned long uninitialized_var(flags);
1146 spin_lock_irqsave(&n->list_lock, flags);
1149 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1150 if (!check_slab(s, page))
1157 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1158 if (!free_consistency_checks(s, page, object, addr))
1162 if (s->flags & SLAB_STORE_USER)
1163 set_track(s, object, TRACK_FREE, addr);
1164 trace(s, page, object, 0);
1165 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1166 init_object(s, object, SLUB_RED_INACTIVE);
1168 /* Reached end of constructed freelist yet? */
1169 if (object != tail) {
1170 object = get_freepointer(s, object);
1176 if (cnt != bulk_cnt)
1177 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1181 spin_unlock_irqrestore(&n->list_lock, flags);
1183 slab_fix(s, "Object at 0x%p not freed", object);
1187 static int __init setup_slub_debug(char *str)
1189 slub_debug = DEBUG_DEFAULT_FLAGS;
1190 if (*str++ != '=' || !*str)
1192 * No options specified. Switch on full debugging.
1198 * No options but restriction on slabs. This means full
1199 * debugging for slabs matching a pattern.
1206 * Switch off all debugging measures.
1211 * Determine which debug features should be switched on
1213 for (; *str && *str != ','; str++) {
1214 switch (tolower(*str)) {
1216 slub_debug |= SLAB_CONSISTENCY_CHECKS;
1219 slub_debug |= SLAB_RED_ZONE;
1222 slub_debug |= SLAB_POISON;
1225 slub_debug |= SLAB_STORE_USER;
1228 slub_debug |= SLAB_TRACE;
1231 slub_debug |= SLAB_FAILSLAB;
1235 * Avoid enabling debugging on caches if its minimum
1236 * order would increase as a result.
1238 disable_higher_order_debug = 1;
1241 pr_err("slub_debug option '%c' unknown. skipped\n",
1248 slub_debug_slabs = str + 1;
1253 __setup("slub_debug", setup_slub_debug);
1255 unsigned long kmem_cache_flags(unsigned long object_size,
1256 unsigned long flags, const char *name,
1257 void (*ctor)(void *))
1260 * Enable debugging if selected on the kernel commandline.
1262 if (slub_debug && (!slub_debug_slabs || (name &&
1263 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))))
1264 flags |= slub_debug;
1268 #else /* !CONFIG_SLUB_DEBUG */
1269 static inline void setup_object_debug(struct kmem_cache *s,
1270 struct page *page, void *object) {}
1272 static inline int alloc_debug_processing(struct kmem_cache *s,
1273 struct page *page, void *object, unsigned long addr) { return 0; }
1275 static inline int free_debug_processing(
1276 struct kmem_cache *s, struct page *page,
1277 void *head, void *tail, int bulk_cnt,
1278 unsigned long addr) { return 0; }
1280 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1282 static inline int check_object(struct kmem_cache *s, struct page *page,
1283 void *object, u8 val) { return 1; }
1284 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1285 struct page *page) {}
1286 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1287 struct page *page) {}
1288 unsigned long kmem_cache_flags(unsigned long object_size,
1289 unsigned long flags, const char *name,
1290 void (*ctor)(void *))
1294 #define slub_debug 0
1296 #define disable_higher_order_debug 0
1298 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1300 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1302 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1304 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1307 #endif /* CONFIG_SLUB_DEBUG */
1310 * Hooks for other subsystems that check memory allocations. In a typical
1311 * production configuration these hooks all should produce no code at all.
1313 static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1315 kmemleak_alloc(ptr, size, 1, flags);
1316 kasan_kmalloc_large(ptr, size, flags);
1319 static inline void kfree_hook(const void *x)
1322 kasan_kfree_large(x);
1325 static inline void slab_free_hook(struct kmem_cache *s, void *x)
1327 kmemleak_free_recursive(x, s->flags);
1330 * Trouble is that we may no longer disable interrupts in the fast path
1331 * So in order to make the debug calls that expect irqs to be
1332 * disabled we need to disable interrupts temporarily.
1334 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1336 unsigned long flags;
1338 local_irq_save(flags);
1339 kmemcheck_slab_free(s, x, s->object_size);
1340 debug_check_no_locks_freed(x, s->object_size);
1341 local_irq_restore(flags);
1344 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1345 debug_check_no_obj_freed(x, s->object_size);
1347 kasan_slab_free(s, x);
1350 static inline void slab_free_freelist_hook(struct kmem_cache *s,
1351 void *head, void *tail)
1354 * Compiler cannot detect this function can be removed if slab_free_hook()
1355 * evaluates to nothing. Thus, catch all relevant config debug options here.
1357 #if defined(CONFIG_KMEMCHECK) || \
1358 defined(CONFIG_LOCKDEP) || \
1359 defined(CONFIG_DEBUG_KMEMLEAK) || \
1360 defined(CONFIG_DEBUG_OBJECTS_FREE) || \
1361 defined(CONFIG_KASAN)
1363 void *object = head;
1364 void *tail_obj = tail ? : head;
1367 slab_free_hook(s, object);
1368 } while ((object != tail_obj) &&
1369 (object = get_freepointer(s, object)));
1373 static void setup_object(struct kmem_cache *s, struct page *page,
1376 setup_object_debug(s, page, object);
1377 if (unlikely(s->ctor)) {
1378 kasan_unpoison_object_data(s, object);
1380 kasan_poison_object_data(s, object);
1385 * Slab allocation and freeing
1387 static inline struct page *alloc_slab_page(struct kmem_cache *s,
1388 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1391 int order = oo_order(oo);
1393 flags |= __GFP_NOTRACK;
1395 if (node == NUMA_NO_NODE)
1396 page = alloc_pages(flags, order);
1398 page = __alloc_pages_node(node, flags, order);
1400 if (page && memcg_charge_slab(page, flags, order, s)) {
1401 __free_pages(page, order);
1408 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1409 /* Pre-initialize the random sequence cache */
1410 static int init_cache_random_seq(struct kmem_cache *s)
1413 unsigned long i, count = oo_objects(s->oo);
1415 err = cache_random_seq_create(s, count, GFP_KERNEL);
1417 pr_err("SLUB: Unable to initialize free list for %s\n",
1422 /* Transform to an offset on the set of pages */
1423 if (s->random_seq) {
1424 for (i = 0; i < count; i++)
1425 s->random_seq[i] *= s->size;
1430 /* Initialize each random sequence freelist per cache */
1431 static void __init init_freelist_randomization(void)
1433 struct kmem_cache *s;
1435 mutex_lock(&slab_mutex);
1437 list_for_each_entry(s, &slab_caches, list)
1438 init_cache_random_seq(s);
1440 mutex_unlock(&slab_mutex);
1443 /* Get the next entry on the pre-computed freelist randomized */
1444 static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1445 unsigned long *pos, void *start,
1446 unsigned long page_limit,
1447 unsigned long freelist_count)
1452 * If the target page allocation failed, the number of objects on the
1453 * page might be smaller than the usual size defined by the cache.
1456 idx = s->random_seq[*pos];
1458 if (*pos >= freelist_count)
1460 } while (unlikely(idx >= page_limit));
1462 return (char *)start + idx;
1465 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1466 static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1471 unsigned long idx, pos, page_limit, freelist_count;
1473 if (page->objects < 2 || !s->random_seq)
1476 freelist_count = oo_objects(s->oo);
1477 pos = get_random_int() % freelist_count;
1479 page_limit = page->objects * s->size;
1480 start = fixup_red_left(s, page_address(page));
1482 /* First entry is used as the base of the freelist */
1483 cur = next_freelist_entry(s, page, &pos, start, page_limit,
1485 page->freelist = cur;
1487 for (idx = 1; idx < page->objects; idx++) {
1488 setup_object(s, page, cur);
1489 next = next_freelist_entry(s, page, &pos, start, page_limit,
1491 set_freepointer(s, cur, next);
1494 setup_object(s, page, cur);
1495 set_freepointer(s, cur, NULL);
1500 static inline int init_cache_random_seq(struct kmem_cache *s)
1504 static inline void init_freelist_randomization(void) { }
1505 static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1509 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1511 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1514 struct kmem_cache_order_objects oo = s->oo;
1520 flags &= gfp_allowed_mask;
1522 if (gfpflags_allow_blocking(flags))
1525 flags |= s->allocflags;
1528 * Let the initial higher-order allocation fail under memory pressure
1529 * so we fall-back to the minimum order allocation.
1531 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1532 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1533 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1535 page = alloc_slab_page(s, alloc_gfp, node, oo);
1536 if (unlikely(!page)) {
1540 * Allocation may have failed due to fragmentation.
1541 * Try a lower order alloc if possible
1543 page = alloc_slab_page(s, alloc_gfp, node, oo);
1544 if (unlikely(!page))
1546 stat(s, ORDER_FALLBACK);
1549 if (kmemcheck_enabled &&
1550 !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1551 int pages = 1 << oo_order(oo);
1553 kmemcheck_alloc_shadow(page, oo_order(oo), alloc_gfp, node);
1556 * Objects from caches that have a constructor don't get
1557 * cleared when they're allocated, so we need to do it here.
1560 kmemcheck_mark_uninitialized_pages(page, pages);
1562 kmemcheck_mark_unallocated_pages(page, pages);
1565 page->objects = oo_objects(oo);
1567 order = compound_order(page);
1568 page->slab_cache = s;
1569 __SetPageSlab(page);
1570 if (page_is_pfmemalloc(page))
1571 SetPageSlabPfmemalloc(page);
1573 start = page_address(page);
1575 if (unlikely(s->flags & SLAB_POISON))
1576 memset(start, POISON_INUSE, PAGE_SIZE << order);
1578 kasan_poison_slab(page);
1580 shuffle = shuffle_freelist(s, page);
1583 for_each_object_idx(p, idx, s, start, page->objects) {
1584 setup_object(s, page, p);
1585 if (likely(idx < page->objects))
1586 set_freepointer(s, p, p + s->size);
1588 set_freepointer(s, p, NULL);
1590 page->freelist = fixup_red_left(s, start);
1593 page->inuse = page->objects;
1597 if (gfpflags_allow_blocking(flags))
1598 local_irq_disable();
1602 mod_zone_page_state(page_zone(page),
1603 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1604 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1607 inc_slabs_node(s, page_to_nid(page), page->objects);
1612 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1614 if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1615 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1616 flags &= ~GFP_SLAB_BUG_MASK;
1617 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1618 invalid_mask, &invalid_mask, flags, &flags);
1621 return allocate_slab(s,
1622 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1625 static void __free_slab(struct kmem_cache *s, struct page *page)
1627 int order = compound_order(page);
1628 int pages = 1 << order;
1630 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1633 slab_pad_check(s, page);
1634 for_each_object(p, s, page_address(page),
1636 check_object(s, page, p, SLUB_RED_INACTIVE);
1639 kmemcheck_free_shadow(page, compound_order(page));
1641 mod_zone_page_state(page_zone(page),
1642 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1643 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1646 __ClearPageSlabPfmemalloc(page);
1647 __ClearPageSlab(page);
1649 page_mapcount_reset(page);
1650 if (current->reclaim_state)
1651 current->reclaim_state->reclaimed_slab += pages;
1652 memcg_uncharge_slab(page, order, s);
1653 __free_pages(page, order);
1656 #define need_reserve_slab_rcu \
1657 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1659 static void rcu_free_slab(struct rcu_head *h)
1663 if (need_reserve_slab_rcu)
1664 page = virt_to_head_page(h);
1666 page = container_of((struct list_head *)h, struct page, lru);
1668 __free_slab(page->slab_cache, page);
1671 static void free_slab(struct kmem_cache *s, struct page *page)
1673 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1674 struct rcu_head *head;
1676 if (need_reserve_slab_rcu) {
1677 int order = compound_order(page);
1678 int offset = (PAGE_SIZE << order) - s->reserved;
1680 VM_BUG_ON(s->reserved != sizeof(*head));
1681 head = page_address(page) + offset;
1683 head = &page->rcu_head;
1686 call_rcu(head, rcu_free_slab);
1688 __free_slab(s, page);
1691 static void discard_slab(struct kmem_cache *s, struct page *page)
1693 dec_slabs_node(s, page_to_nid(page), page->objects);
1698 * Management of partially allocated slabs.
1701 __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1704 if (tail == DEACTIVATE_TO_TAIL)
1705 list_add_tail(&page->lru, &n->partial);
1707 list_add(&page->lru, &n->partial);
1710 static inline void add_partial(struct kmem_cache_node *n,
1711 struct page *page, int tail)
1713 lockdep_assert_held(&n->list_lock);
1714 __add_partial(n, page, tail);
1717 static inline void remove_partial(struct kmem_cache_node *n,
1720 lockdep_assert_held(&n->list_lock);
1721 list_del(&page->lru);
1726 * Remove slab from the partial list, freeze it and
1727 * return the pointer to the freelist.
1729 * Returns a list of objects or NULL if it fails.
1731 static inline void *acquire_slab(struct kmem_cache *s,
1732 struct kmem_cache_node *n, struct page *page,
1733 int mode, int *objects)
1736 unsigned long counters;
1739 lockdep_assert_held(&n->list_lock);
1742 * Zap the freelist and set the frozen bit.
1743 * The old freelist is the list of objects for the
1744 * per cpu allocation list.
1746 freelist = page->freelist;
1747 counters = page->counters;
1748 new.counters = counters;
1749 *objects = new.objects - new.inuse;
1751 new.inuse = page->objects;
1752 new.freelist = NULL;
1754 new.freelist = freelist;
1757 VM_BUG_ON(new.frozen);
1760 if (!__cmpxchg_double_slab(s, page,
1762 new.freelist, new.counters,
1766 remove_partial(n, page);
1771 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1772 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1775 * Try to allocate a partial slab from a specific node.
1777 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1778 struct kmem_cache_cpu *c, gfp_t flags)
1780 struct page *page, *page2;
1781 void *object = NULL;
1786 * Racy check. If we mistakenly see no partial slabs then we
1787 * just allocate an empty slab. If we mistakenly try to get a
1788 * partial slab and there is none available then get_partials()
1791 if (!n || !n->nr_partial)
1794 spin_lock(&n->list_lock);
1795 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1798 if (!pfmemalloc_match(page, flags))
1801 t = acquire_slab(s, n, page, object == NULL, &objects);
1805 available += objects;
1808 stat(s, ALLOC_FROM_PARTIAL);
1811 put_cpu_partial(s, page, 0);
1812 stat(s, CPU_PARTIAL_NODE);
1814 if (!kmem_cache_has_cpu_partial(s)
1815 || available > s->cpu_partial / 2)
1819 spin_unlock(&n->list_lock);
1824 * Get a page from somewhere. Search in increasing NUMA distances.
1826 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1827 struct kmem_cache_cpu *c)
1830 struct zonelist *zonelist;
1833 enum zone_type high_zoneidx = gfp_zone(flags);
1835 unsigned int cpuset_mems_cookie;
1838 * The defrag ratio allows a configuration of the tradeoffs between
1839 * inter node defragmentation and node local allocations. A lower
1840 * defrag_ratio increases the tendency to do local allocations
1841 * instead of attempting to obtain partial slabs from other nodes.
1843 * If the defrag_ratio is set to 0 then kmalloc() always
1844 * returns node local objects. If the ratio is higher then kmalloc()
1845 * may return off node objects because partial slabs are obtained
1846 * from other nodes and filled up.
1848 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
1849 * (which makes defrag_ratio = 1000) then every (well almost)
1850 * allocation will first attempt to defrag slab caches on other nodes.
1851 * This means scanning over all nodes to look for partial slabs which
1852 * may be expensive if we do it every time we are trying to find a slab
1853 * with available objects.
1855 if (!s->remote_node_defrag_ratio ||
1856 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1860 cpuset_mems_cookie = read_mems_allowed_begin();
1861 zonelist = node_zonelist(mempolicy_slab_node(), flags);
1862 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1863 struct kmem_cache_node *n;
1865 n = get_node(s, zone_to_nid(zone));
1867 if (n && cpuset_zone_allowed(zone, flags) &&
1868 n->nr_partial > s->min_partial) {
1869 object = get_partial_node(s, n, c, flags);
1872 * Don't check read_mems_allowed_retry()
1873 * here - if mems_allowed was updated in
1874 * parallel, that was a harmless race
1875 * between allocation and the cpuset
1882 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1888 * Get a partial page, lock it and return it.
1890 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1891 struct kmem_cache_cpu *c)
1894 int searchnode = node;
1896 if (node == NUMA_NO_NODE)
1897 searchnode = numa_mem_id();
1898 else if (!node_present_pages(node))
1899 searchnode = node_to_mem_node(node);
1901 object = get_partial_node(s, get_node(s, searchnode), c, flags);
1902 if (object || node != NUMA_NO_NODE)
1905 return get_any_partial(s, flags, c);
1908 #ifdef CONFIG_PREEMPT
1910 * Calculate the next globally unique transaction for disambiguiation
1911 * during cmpxchg. The transactions start with the cpu number and are then
1912 * incremented by CONFIG_NR_CPUS.
1914 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1917 * No preemption supported therefore also no need to check for
1923 static inline unsigned long next_tid(unsigned long tid)
1925 return tid + TID_STEP;
1928 static inline unsigned int tid_to_cpu(unsigned long tid)
1930 return tid % TID_STEP;
1933 static inline unsigned long tid_to_event(unsigned long tid)
1935 return tid / TID_STEP;
1938 static inline unsigned int init_tid(int cpu)
1943 static inline void note_cmpxchg_failure(const char *n,
1944 const struct kmem_cache *s, unsigned long tid)
1946 #ifdef SLUB_DEBUG_CMPXCHG
1947 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1949 pr_info("%s %s: cmpxchg redo ", n, s->name);
1951 #ifdef CONFIG_PREEMPT
1952 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1953 pr_warn("due to cpu change %d -> %d\n",
1954 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1957 if (tid_to_event(tid) != tid_to_event(actual_tid))
1958 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1959 tid_to_event(tid), tid_to_event(actual_tid));
1961 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1962 actual_tid, tid, next_tid(tid));
1964 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1967 static void init_kmem_cache_cpus(struct kmem_cache *s)
1971 for_each_possible_cpu(cpu)
1972 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1976 * Remove the cpu slab
1978 static void deactivate_slab(struct kmem_cache *s, struct page *page,
1981 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1982 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1984 enum slab_modes l = M_NONE, m = M_NONE;
1986 int tail = DEACTIVATE_TO_HEAD;
1990 if (page->freelist) {
1991 stat(s, DEACTIVATE_REMOTE_FREES);
1992 tail = DEACTIVATE_TO_TAIL;
1996 * Stage one: Free all available per cpu objects back
1997 * to the page freelist while it is still frozen. Leave the
2000 * There is no need to take the list->lock because the page
2003 while (freelist && (nextfree = get_freepointer(s, freelist))) {
2005 unsigned long counters;
2008 prior = page->freelist;
2009 counters = page->counters;
2010 set_freepointer(s, freelist, prior);
2011 new.counters = counters;
2013 VM_BUG_ON(!new.frozen);
2015 } while (!__cmpxchg_double_slab(s, page,
2017 freelist, new.counters,
2018 "drain percpu freelist"));
2020 freelist = nextfree;
2024 * Stage two: Ensure that the page is unfrozen while the
2025 * list presence reflects the actual number of objects
2028 * We setup the list membership and then perform a cmpxchg
2029 * with the count. If there is a mismatch then the page
2030 * is not unfrozen but the page is on the wrong list.
2032 * Then we restart the process which may have to remove
2033 * the page from the list that we just put it on again
2034 * because the number of objects in the slab may have
2039 old.freelist = page->freelist;
2040 old.counters = page->counters;
2041 VM_BUG_ON(!old.frozen);
2043 /* Determine target state of the slab */
2044 new.counters = old.counters;
2047 set_freepointer(s, freelist, old.freelist);
2048 new.freelist = freelist;
2050 new.freelist = old.freelist;
2054 if (!new.inuse && n->nr_partial >= s->min_partial)
2056 else if (new.freelist) {
2061 * Taking the spinlock removes the possiblity
2062 * that acquire_slab() will see a slab page that
2065 spin_lock(&n->list_lock);
2069 if (kmem_cache_debug(s) && !lock) {
2072 * This also ensures that the scanning of full
2073 * slabs from diagnostic functions will not see
2076 spin_lock(&n->list_lock);
2084 remove_partial(n, page);
2086 else if (l == M_FULL)
2088 remove_full(s, n, page);
2090 if (m == M_PARTIAL) {
2092 add_partial(n, page, tail);
2095 } else if (m == M_FULL) {
2097 stat(s, DEACTIVATE_FULL);
2098 add_full(s, n, page);
2104 if (!__cmpxchg_double_slab(s, page,
2105 old.freelist, old.counters,
2106 new.freelist, new.counters,
2111 spin_unlock(&n->list_lock);
2114 stat(s, DEACTIVATE_EMPTY);
2115 discard_slab(s, page);
2121 * Unfreeze all the cpu partial slabs.
2123 * This function must be called with interrupts disabled
2124 * for the cpu using c (or some other guarantee must be there
2125 * to guarantee no concurrent accesses).
2127 static void unfreeze_partials(struct kmem_cache *s,
2128 struct kmem_cache_cpu *c)
2130 #ifdef CONFIG_SLUB_CPU_PARTIAL
2131 struct kmem_cache_node *n = NULL, *n2 = NULL;
2132 struct page *page, *discard_page = NULL;
2134 while ((page = c->partial)) {
2138 c->partial = page->next;
2140 n2 = get_node(s, page_to_nid(page));
2143 spin_unlock(&n->list_lock);
2146 spin_lock(&n->list_lock);
2151 old.freelist = page->freelist;
2152 old.counters = page->counters;
2153 VM_BUG_ON(!old.frozen);
2155 new.counters = old.counters;
2156 new.freelist = old.freelist;
2160 } while (!__cmpxchg_double_slab(s, page,
2161 old.freelist, old.counters,
2162 new.freelist, new.counters,
2163 "unfreezing slab"));
2165 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2166 page->next = discard_page;
2167 discard_page = page;
2169 add_partial(n, page, DEACTIVATE_TO_TAIL);
2170 stat(s, FREE_ADD_PARTIAL);
2175 spin_unlock(&n->list_lock);
2177 while (discard_page) {
2178 page = discard_page;
2179 discard_page = discard_page->next;
2181 stat(s, DEACTIVATE_EMPTY);
2182 discard_slab(s, page);
2189 * Put a page that was just frozen (in __slab_free) into a partial page
2190 * slot if available. This is done without interrupts disabled and without
2191 * preemption disabled. The cmpxchg is racy and may put the partial page
2192 * onto a random cpus partial slot.
2194 * If we did not find a slot then simply move all the partials to the
2195 * per node partial list.
2197 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2199 #ifdef CONFIG_SLUB_CPU_PARTIAL
2200 struct page *oldpage;
2208 oldpage = this_cpu_read(s->cpu_slab->partial);
2211 pobjects = oldpage->pobjects;
2212 pages = oldpage->pages;
2213 if (drain && pobjects > s->cpu_partial) {
2214 unsigned long flags;
2216 * partial array is full. Move the existing
2217 * set to the per node partial list.
2219 local_irq_save(flags);
2220 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2221 local_irq_restore(flags);
2225 stat(s, CPU_PARTIAL_DRAIN);
2230 pobjects += page->objects - page->inuse;
2232 page->pages = pages;
2233 page->pobjects = pobjects;
2234 page->next = oldpage;
2236 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2238 if (unlikely(!s->cpu_partial)) {
2239 unsigned long flags;
2241 local_irq_save(flags);
2242 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2243 local_irq_restore(flags);
2249 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2251 stat(s, CPUSLAB_FLUSH);
2252 deactivate_slab(s, c->page, c->freelist);
2254 c->tid = next_tid(c->tid);
2262 * Called from IPI handler with interrupts disabled.
2264 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2266 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2272 unfreeze_partials(s, c);
2276 static void flush_cpu_slab(void *d)
2278 struct kmem_cache *s = d;
2280 __flush_cpu_slab(s, smp_processor_id());
2283 static bool has_cpu_slab(int cpu, void *info)
2285 struct kmem_cache *s = info;
2286 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2288 return c->page || c->partial;
2291 static void flush_all(struct kmem_cache *s)
2293 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2297 * Check if the objects in a per cpu structure fit numa
2298 * locality expectations.
2300 static inline int node_match(struct page *page, int node)
2303 if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2309 #ifdef CONFIG_SLUB_DEBUG
2310 static int count_free(struct page *page)
2312 return page->objects - page->inuse;
2315 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2317 return atomic_long_read(&n->total_objects);
2319 #endif /* CONFIG_SLUB_DEBUG */
2321 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2322 static unsigned long count_partial(struct kmem_cache_node *n,
2323 int (*get_count)(struct page *))
2325 unsigned long flags;
2326 unsigned long x = 0;
2329 spin_lock_irqsave(&n->list_lock, flags);
2330 list_for_each_entry(page, &n->partial, lru)
2331 x += get_count(page);
2332 spin_unlock_irqrestore(&n->list_lock, flags);
2335 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2337 static noinline void
2338 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2340 #ifdef CONFIG_SLUB_DEBUG
2341 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2342 DEFAULT_RATELIMIT_BURST);
2344 struct kmem_cache_node *n;
2346 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2349 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2350 nid, gfpflags, &gfpflags);
2351 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2352 s->name, s->object_size, s->size, oo_order(s->oo),
2355 if (oo_order(s->min) > get_order(s->object_size))
2356 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2359 for_each_kmem_cache_node(s, node, n) {
2360 unsigned long nr_slabs;
2361 unsigned long nr_objs;
2362 unsigned long nr_free;
2364 nr_free = count_partial(n, count_free);
2365 nr_slabs = node_nr_slabs(n);
2366 nr_objs = node_nr_objs(n);
2368 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2369 node, nr_slabs, nr_objs, nr_free);
2374 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2375 int node, struct kmem_cache_cpu **pc)
2378 struct kmem_cache_cpu *c = *pc;
2381 freelist = get_partial(s, flags, node, c);
2386 page = new_slab(s, flags, node);
2388 c = raw_cpu_ptr(s->cpu_slab);
2393 * No other reference to the page yet so we can
2394 * muck around with it freely without cmpxchg
2396 freelist = page->freelist;
2397 page->freelist = NULL;
2399 stat(s, ALLOC_SLAB);
2408 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2410 if (unlikely(PageSlabPfmemalloc(page)))
2411 return gfp_pfmemalloc_allowed(gfpflags);
2417 * Check the page->freelist of a page and either transfer the freelist to the
2418 * per cpu freelist or deactivate the page.
2420 * The page is still frozen if the return value is not NULL.
2422 * If this function returns NULL then the page has been unfrozen.
2424 * This function must be called with interrupt disabled.
2426 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2429 unsigned long counters;
2433 freelist = page->freelist;
2434 counters = page->counters;
2436 new.counters = counters;
2437 VM_BUG_ON(!new.frozen);
2439 new.inuse = page->objects;
2440 new.frozen = freelist != NULL;
2442 } while (!__cmpxchg_double_slab(s, page,
2451 * Slow path. The lockless freelist is empty or we need to perform
2454 * Processing is still very fast if new objects have been freed to the
2455 * regular freelist. In that case we simply take over the regular freelist
2456 * as the lockless freelist and zap the regular freelist.
2458 * If that is not working then we fall back to the partial lists. We take the
2459 * first element of the freelist as the object to allocate now and move the
2460 * rest of the freelist to the lockless freelist.
2462 * And if we were unable to get a new slab from the partial slab lists then
2463 * we need to allocate a new slab. This is the slowest path since it involves
2464 * a call to the page allocator and the setup of a new slab.
2466 * Version of __slab_alloc to use when we know that interrupts are
2467 * already disabled (which is the case for bulk allocation).
2469 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2470 unsigned long addr, struct kmem_cache_cpu *c)
2480 if (unlikely(!node_match(page, node))) {
2481 int searchnode = node;
2483 if (node != NUMA_NO_NODE && !node_present_pages(node))
2484 searchnode = node_to_mem_node(node);
2486 if (unlikely(!node_match(page, searchnode))) {
2487 stat(s, ALLOC_NODE_MISMATCH);
2488 deactivate_slab(s, page, c->freelist);
2496 * By rights, we should be searching for a slab page that was
2497 * PFMEMALLOC but right now, we are losing the pfmemalloc
2498 * information when the page leaves the per-cpu allocator
2500 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2501 deactivate_slab(s, page, c->freelist);
2507 /* must check again c->freelist in case of cpu migration or IRQ */
2508 freelist = c->freelist;
2512 freelist = get_freelist(s, page);
2516 stat(s, DEACTIVATE_BYPASS);
2520 stat(s, ALLOC_REFILL);
2524 * freelist is pointing to the list of objects to be used.
2525 * page is pointing to the page from which the objects are obtained.
2526 * That page must be frozen for per cpu allocations to work.
2528 VM_BUG_ON(!c->page->frozen);
2529 c->freelist = get_freepointer(s, freelist);
2530 c->tid = next_tid(c->tid);
2536 page = c->page = c->partial;
2537 c->partial = page->next;
2538 stat(s, CPU_PARTIAL_ALLOC);
2543 freelist = new_slab_objects(s, gfpflags, node, &c);
2545 if (unlikely(!freelist)) {
2546 slab_out_of_memory(s, gfpflags, node);
2551 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2554 /* Only entered in the debug case */
2555 if (kmem_cache_debug(s) &&
2556 !alloc_debug_processing(s, page, freelist, addr))
2557 goto new_slab; /* Slab failed checks. Next slab needed */
2559 deactivate_slab(s, page, get_freepointer(s, freelist));
2566 * Another one that disabled interrupt and compensates for possible
2567 * cpu changes by refetching the per cpu area pointer.
2569 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2570 unsigned long addr, struct kmem_cache_cpu *c)
2573 unsigned long flags;
2575 local_irq_save(flags);
2576 #ifdef CONFIG_PREEMPT
2578 * We may have been preempted and rescheduled on a different
2579 * cpu before disabling interrupts. Need to reload cpu area
2582 c = this_cpu_ptr(s->cpu_slab);
2585 p = ___slab_alloc(s, gfpflags, node, addr, c);
2586 local_irq_restore(flags);
2591 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2592 * have the fastpath folded into their functions. So no function call
2593 * overhead for requests that can be satisfied on the fastpath.
2595 * The fastpath works by first checking if the lockless freelist can be used.
2596 * If not then __slab_alloc is called for slow processing.
2598 * Otherwise we can simply pick the next object from the lockless free list.
2600 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2601 gfp_t gfpflags, int node, unsigned long addr)
2604 struct kmem_cache_cpu *c;
2608 s = slab_pre_alloc_hook(s, gfpflags);
2613 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2614 * enabled. We may switch back and forth between cpus while
2615 * reading from one cpu area. That does not matter as long
2616 * as we end up on the original cpu again when doing the cmpxchg.
2618 * We should guarantee that tid and kmem_cache are retrieved on
2619 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2620 * to check if it is matched or not.
2623 tid = this_cpu_read(s->cpu_slab->tid);
2624 c = raw_cpu_ptr(s->cpu_slab);
2625 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2626 unlikely(tid != READ_ONCE(c->tid)));
2629 * Irqless object alloc/free algorithm used here depends on sequence
2630 * of fetching cpu_slab's data. tid should be fetched before anything
2631 * on c to guarantee that object and page associated with previous tid
2632 * won't be used with current tid. If we fetch tid first, object and
2633 * page could be one associated with next tid and our alloc/free
2634 * request will be failed. In this case, we will retry. So, no problem.
2639 * The transaction ids are globally unique per cpu and per operation on
2640 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2641 * occurs on the right processor and that there was no operation on the
2642 * linked list in between.
2645 object = c->freelist;
2647 if (unlikely(!object || !node_match(page, node))) {
2648 object = __slab_alloc(s, gfpflags, node, addr, c);
2649 stat(s, ALLOC_SLOWPATH);
2651 void *next_object = get_freepointer_safe(s, object);
2654 * The cmpxchg will only match if there was no additional
2655 * operation and if we are on the right processor.
2657 * The cmpxchg does the following atomically (without lock
2659 * 1. Relocate first pointer to the current per cpu area.
2660 * 2. Verify that tid and freelist have not been changed
2661 * 3. If they were not changed replace tid and freelist
2663 * Since this is without lock semantics the protection is only
2664 * against code executing on this cpu *not* from access by
2667 if (unlikely(!this_cpu_cmpxchg_double(
2668 s->cpu_slab->freelist, s->cpu_slab->tid,
2670 next_object, next_tid(tid)))) {
2672 note_cmpxchg_failure("slab_alloc", s, tid);
2675 prefetch_freepointer(s, next_object);
2676 stat(s, ALLOC_FASTPATH);
2679 if (unlikely(gfpflags & __GFP_ZERO) && object)
2680 memset(object, 0, s->object_size);
2682 slab_post_alloc_hook(s, gfpflags, 1, &object);
2687 static __always_inline void *slab_alloc(struct kmem_cache *s,
2688 gfp_t gfpflags, unsigned long addr)
2690 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2693 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2695 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2697 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2702 EXPORT_SYMBOL(kmem_cache_alloc);
2704 #ifdef CONFIG_TRACING
2705 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2707 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2708 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2709 kasan_kmalloc(s, ret, size, gfpflags);
2712 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2716 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2718 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2720 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2721 s->object_size, s->size, gfpflags, node);
2725 EXPORT_SYMBOL(kmem_cache_alloc_node);
2727 #ifdef CONFIG_TRACING
2728 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2730 int node, size_t size)
2732 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2734 trace_kmalloc_node(_RET_IP_, ret,
2735 size, s->size, gfpflags, node);
2737 kasan_kmalloc(s, ret, size, gfpflags);
2740 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2745 * Slow path handling. This may still be called frequently since objects
2746 * have a longer lifetime than the cpu slabs in most processing loads.
2748 * So we still attempt to reduce cache line usage. Just take the slab
2749 * lock and free the item. If there is no additional partial page
2750 * handling required then we can return immediately.
2752 static void __slab_free(struct kmem_cache *s, struct page *page,
2753 void *head, void *tail, int cnt,
2760 unsigned long counters;
2761 struct kmem_cache_node *n = NULL;
2762 unsigned long uninitialized_var(flags);
2764 stat(s, FREE_SLOWPATH);
2766 if (kmem_cache_debug(s) &&
2767 !free_debug_processing(s, page, head, tail, cnt, addr))
2772 spin_unlock_irqrestore(&n->list_lock, flags);
2775 prior = page->freelist;
2776 counters = page->counters;
2777 set_freepointer(s, tail, prior);
2778 new.counters = counters;
2779 was_frozen = new.frozen;
2781 if ((!new.inuse || !prior) && !was_frozen) {
2783 if (kmem_cache_has_cpu_partial(s) && !prior) {
2786 * Slab was on no list before and will be
2788 * We can defer the list move and instead
2793 } else { /* Needs to be taken off a list */
2795 n = get_node(s, page_to_nid(page));
2797 * Speculatively acquire the list_lock.
2798 * If the cmpxchg does not succeed then we may
2799 * drop the list_lock without any processing.
2801 * Otherwise the list_lock will synchronize with
2802 * other processors updating the list of slabs.
2804 spin_lock_irqsave(&n->list_lock, flags);
2809 } while (!cmpxchg_double_slab(s, page,
2817 * If we just froze the page then put it onto the
2818 * per cpu partial list.
2820 if (new.frozen && !was_frozen) {
2821 put_cpu_partial(s, page, 1);
2822 stat(s, CPU_PARTIAL_FREE);
2825 * The list lock was not taken therefore no list
2826 * activity can be necessary.
2829 stat(s, FREE_FROZEN);
2833 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2837 * Objects left in the slab. If it was not on the partial list before
2840 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2841 if (kmem_cache_debug(s))
2842 remove_full(s, n, page);
2843 add_partial(n, page, DEACTIVATE_TO_TAIL);
2844 stat(s, FREE_ADD_PARTIAL);
2846 spin_unlock_irqrestore(&n->list_lock, flags);
2852 * Slab on the partial list.
2854 remove_partial(n, page);
2855 stat(s, FREE_REMOVE_PARTIAL);
2857 /* Slab must be on the full list */
2858 remove_full(s, n, page);
2861 spin_unlock_irqrestore(&n->list_lock, flags);
2863 discard_slab(s, page);
2867 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2868 * can perform fastpath freeing without additional function calls.
2870 * The fastpath is only possible if we are freeing to the current cpu slab
2871 * of this processor. This typically the case if we have just allocated
2874 * If fastpath is not possible then fall back to __slab_free where we deal
2875 * with all sorts of special processing.
2877 * Bulk free of a freelist with several objects (all pointing to the
2878 * same page) possible by specifying head and tail ptr, plus objects
2879 * count (cnt). Bulk free indicated by tail pointer being set.
2881 static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2882 void *head, void *tail, int cnt,
2885 void *tail_obj = tail ? : head;
2886 struct kmem_cache_cpu *c;
2889 slab_free_freelist_hook(s, head, tail);
2893 * Determine the currently cpus per cpu slab.
2894 * The cpu may change afterward. However that does not matter since
2895 * data is retrieved via this pointer. If we are on the same cpu
2896 * during the cmpxchg then the free will succeed.
2899 tid = this_cpu_read(s->cpu_slab->tid);
2900 c = raw_cpu_ptr(s->cpu_slab);
2901 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2902 unlikely(tid != READ_ONCE(c->tid)));
2904 /* Same with comment on barrier() in slab_alloc_node() */
2907 if (likely(page == c->page)) {
2908 set_freepointer(s, tail_obj, c->freelist);
2910 if (unlikely(!this_cpu_cmpxchg_double(
2911 s->cpu_slab->freelist, s->cpu_slab->tid,
2913 head, next_tid(tid)))) {
2915 note_cmpxchg_failure("slab_free", s, tid);
2918 stat(s, FREE_FASTPATH);
2920 __slab_free(s, page, head, tail_obj, cnt, addr);
2924 void kmem_cache_free(struct kmem_cache *s, void *x)
2926 s = cache_from_obj(s, x);
2929 slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
2930 trace_kmem_cache_free(_RET_IP_, x);
2932 EXPORT_SYMBOL(kmem_cache_free);
2934 struct detached_freelist {
2939 struct kmem_cache *s;
2943 * This function progressively scans the array with free objects (with
2944 * a limited look ahead) and extract objects belonging to the same
2945 * page. It builds a detached freelist directly within the given
2946 * page/objects. This can happen without any need for
2947 * synchronization, because the objects are owned by running process.
2948 * The freelist is build up as a single linked list in the objects.
2949 * The idea is, that this detached freelist can then be bulk
2950 * transferred to the real freelist(s), but only requiring a single
2951 * synchronization primitive. Look ahead in the array is limited due
2952 * to performance reasons.
2955 int build_detached_freelist(struct kmem_cache *s, size_t size,
2956 void **p, struct detached_freelist *df)
2958 size_t first_skipped_index = 0;
2963 /* Always re-init detached_freelist */
2968 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
2969 } while (!object && size);
2974 page = virt_to_head_page(object);
2976 /* Handle kalloc'ed objects */
2977 if (unlikely(!PageSlab(page))) {
2978 BUG_ON(!PageCompound(page));
2980 __free_pages(page, compound_order(page));
2981 p[size] = NULL; /* mark object processed */
2984 /* Derive kmem_cache from object */
2985 df->s = page->slab_cache;
2987 df->s = cache_from_obj(s, object); /* Support for memcg */
2990 /* Start new detached freelist */
2992 set_freepointer(df->s, object, NULL);
2994 df->freelist = object;
2995 p[size] = NULL; /* mark object processed */
3001 continue; /* Skip processed objects */
3003 /* df->page is always set at this point */
3004 if (df->page == virt_to_head_page(object)) {
3005 /* Opportunity build freelist */
3006 set_freepointer(df->s, object, df->freelist);
3007 df->freelist = object;
3009 p[size] = NULL; /* mark object processed */
3014 /* Limit look ahead search */
3018 if (!first_skipped_index)
3019 first_skipped_index = size + 1;
3022 return first_skipped_index;
3025 /* Note that interrupts must be enabled when calling this function. */
3026 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3032 struct detached_freelist df;
3034 size = build_detached_freelist(s, size, p, &df);
3035 if (unlikely(!df.page))
3038 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3039 } while (likely(size));
3041 EXPORT_SYMBOL(kmem_cache_free_bulk);
3043 /* Note that interrupts must be enabled when calling this function. */
3044 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3047 struct kmem_cache_cpu *c;
3050 /* memcg and kmem_cache debug support */
3051 s = slab_pre_alloc_hook(s, flags);
3055 * Drain objects in the per cpu slab, while disabling local
3056 * IRQs, which protects against PREEMPT and interrupts
3057 * handlers invoking normal fastpath.
3059 local_irq_disable();
3060 c = this_cpu_ptr(s->cpu_slab);
3062 for (i = 0; i < size; i++) {
3063 void *object = c->freelist;
3065 if (unlikely(!object)) {
3067 * Invoking slow path likely have side-effect
3068 * of re-populating per CPU c->freelist
3070 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3072 if (unlikely(!p[i]))
3075 c = this_cpu_ptr(s->cpu_slab);
3076 continue; /* goto for-loop */
3078 c->freelist = get_freepointer(s, object);
3081 c->tid = next_tid(c->tid);
3084 /* Clear memory outside IRQ disabled fastpath loop */
3085 if (unlikely(flags & __GFP_ZERO)) {
3088 for (j = 0; j < i; j++)
3089 memset(p[j], 0, s->object_size);
3092 /* memcg and kmem_cache debug support */
3093 slab_post_alloc_hook(s, flags, size, p);
3097 slab_post_alloc_hook(s, flags, i, p);
3098 __kmem_cache_free_bulk(s, i, p);
3101 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3105 * Object placement in a slab is made very easy because we always start at
3106 * offset 0. If we tune the size of the object to the alignment then we can
3107 * get the required alignment by putting one properly sized object after
3110 * Notice that the allocation order determines the sizes of the per cpu
3111 * caches. Each processor has always one slab available for allocations.
3112 * Increasing the allocation order reduces the number of times that slabs
3113 * must be moved on and off the partial lists and is therefore a factor in
3118 * Mininum / Maximum order of slab pages. This influences locking overhead
3119 * and slab fragmentation. A higher order reduces the number of partial slabs
3120 * and increases the number of allocations possible without having to
3121 * take the list_lock.
3123 static int slub_min_order;
3124 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3125 static int slub_min_objects;
3128 * Calculate the order of allocation given an slab object size.
3130 * The order of allocation has significant impact on performance and other
3131 * system components. Generally order 0 allocations should be preferred since
3132 * order 0 does not cause fragmentation in the page allocator. Larger objects
3133 * be problematic to put into order 0 slabs because there may be too much
3134 * unused space left. We go to a higher order if more than 1/16th of the slab
3137 * In order to reach satisfactory performance we must ensure that a minimum
3138 * number of objects is in one slab. Otherwise we may generate too much
3139 * activity on the partial lists which requires taking the list_lock. This is
3140 * less a concern for large slabs though which are rarely used.
3142 * slub_max_order specifies the order where we begin to stop considering the
3143 * number of objects in a slab as critical. If we reach slub_max_order then
3144 * we try to keep the page order as low as possible. So we accept more waste
3145 * of space in favor of a small page order.
3147 * Higher order allocations also allow the placement of more objects in a
3148 * slab and thereby reduce object handling overhead. If the user has
3149 * requested a higher mininum order then we start with that one instead of
3150 * the smallest order which will fit the object.
3152 static inline int slab_order(int size, int min_objects,
3153 int max_order, int fract_leftover, int reserved)
3157 int min_order = slub_min_order;
3159 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
3160 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3162 for (order = max(min_order, get_order(min_objects * size + reserved));
3163 order <= max_order; order++) {
3165 unsigned long slab_size = PAGE_SIZE << order;
3167 rem = (slab_size - reserved) % size;
3169 if (rem <= slab_size / fract_leftover)
3176 static inline int calculate_order(int size, int reserved)
3184 * Attempt to find best configuration for a slab. This
3185 * works by first attempting to generate a layout with
3186 * the best configuration and backing off gradually.
3188 * First we increase the acceptable waste in a slab. Then
3189 * we reduce the minimum objects required in a slab.
3191 min_objects = slub_min_objects;
3193 min_objects = 4 * (fls(nr_cpu_ids) + 1);
3194 max_objects = order_objects(slub_max_order, size, reserved);
3195 min_objects = min(min_objects, max_objects);
3197 while (min_objects > 1) {
3199 while (fraction >= 4) {
3200 order = slab_order(size, min_objects,
3201 slub_max_order, fraction, reserved);
3202 if (order <= slub_max_order)
3210 * We were unable to place multiple objects in a slab. Now
3211 * lets see if we can place a single object there.
3213 order = slab_order(size, 1, slub_max_order, 1, reserved);
3214 if (order <= slub_max_order)
3218 * Doh this slab cannot be placed using slub_max_order.
3220 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
3221 if (order < MAX_ORDER)
3227 init_kmem_cache_node(struct kmem_cache_node *n)
3230 spin_lock_init(&n->list_lock);
3231 INIT_LIST_HEAD(&n->partial);
3232 #ifdef CONFIG_SLUB_DEBUG
3233 atomic_long_set(&n->nr_slabs, 0);
3234 atomic_long_set(&n->total_objects, 0);
3235 INIT_LIST_HEAD(&n->full);
3239 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3241 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3242 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3245 * Must align to double word boundary for the double cmpxchg
3246 * instructions to work; see __pcpu_double_call_return_bool().
3248 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3249 2 * sizeof(void *));
3254 init_kmem_cache_cpus(s);
3259 static struct kmem_cache *kmem_cache_node;
3262 * No kmalloc_node yet so do it by hand. We know that this is the first
3263 * slab on the node for this slabcache. There are no concurrent accesses
3266 * Note that this function only works on the kmem_cache_node
3267 * when allocating for the kmem_cache_node. This is used for bootstrapping
3268 * memory on a fresh node that has no slab structures yet.
3270 static void early_kmem_cache_node_alloc(int node)
3273 struct kmem_cache_node *n;
3275 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3277 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3280 if (page_to_nid(page) != node) {
3281 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3282 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3287 page->freelist = get_freepointer(kmem_cache_node, n);
3290 kmem_cache_node->node[node] = n;
3291 #ifdef CONFIG_SLUB_DEBUG
3292 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3293 init_tracking(kmem_cache_node, n);
3295 kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3297 init_kmem_cache_node(n);
3298 inc_slabs_node(kmem_cache_node, node, page->objects);
3301 * No locks need to be taken here as it has just been
3302 * initialized and there is no concurrent access.
3304 __add_partial(n, page, DEACTIVATE_TO_HEAD);
3307 static void free_kmem_cache_nodes(struct kmem_cache *s)
3310 struct kmem_cache_node *n;
3312 for_each_kmem_cache_node(s, node, n) {
3313 kmem_cache_free(kmem_cache_node, n);
3314 s->node[node] = NULL;
3318 void __kmem_cache_release(struct kmem_cache *s)
3320 cache_random_seq_destroy(s);
3321 free_percpu(s->cpu_slab);
3322 free_kmem_cache_nodes(s);
3325 static int init_kmem_cache_nodes(struct kmem_cache *s)
3329 for_each_node_state(node, N_NORMAL_MEMORY) {
3330 struct kmem_cache_node *n;
3332 if (slab_state == DOWN) {
3333 early_kmem_cache_node_alloc(node);
3336 n = kmem_cache_alloc_node(kmem_cache_node,
3340 free_kmem_cache_nodes(s);
3345 init_kmem_cache_node(n);
3350 static void set_min_partial(struct kmem_cache *s, unsigned long min)
3352 if (min < MIN_PARTIAL)
3354 else if (min > MAX_PARTIAL)
3356 s->min_partial = min;
3360 * calculate_sizes() determines the order and the distribution of data within
3363 static int calculate_sizes(struct kmem_cache *s, int forced_order)
3365 unsigned long flags = s->flags;
3366 unsigned long size = s->object_size;
3370 * Round up object size to the next word boundary. We can only
3371 * place the free pointer at word boundaries and this determines
3372 * the possible location of the free pointer.
3374 size = ALIGN(size, sizeof(void *));
3376 #ifdef CONFIG_SLUB_DEBUG
3378 * Determine if we can poison the object itself. If the user of
3379 * the slab may touch the object after free or before allocation
3380 * then we should never poison the object itself.
3382 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
3384 s->flags |= __OBJECT_POISON;
3386 s->flags &= ~__OBJECT_POISON;
3390 * If we are Redzoning then check if there is some space between the
3391 * end of the object and the free pointer. If not then add an
3392 * additional word to have some bytes to store Redzone information.
3394 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3395 size += sizeof(void *);
3399 * With that we have determined the number of bytes in actual use
3400 * by the object. This is the potential offset to the free pointer.
3404 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
3407 * Relocate free pointer after the object if it is not
3408 * permitted to overwrite the first word of the object on
3411 * This is the case if we do RCU, have a constructor or
3412 * destructor or are poisoning the objects.
3415 size += sizeof(void *);
3418 #ifdef CONFIG_SLUB_DEBUG
3419 if (flags & SLAB_STORE_USER)
3421 * Need to store information about allocs and frees after
3424 size += 2 * sizeof(struct track);
3426 if (flags & SLAB_RED_ZONE) {
3428 * Add some empty padding so that we can catch
3429 * overwrites from earlier objects rather than let
3430 * tracking information or the free pointer be
3431 * corrupted if a user writes before the start
3434 size += sizeof(void *);
3436 s->red_left_pad = sizeof(void *);
3437 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3438 size += s->red_left_pad;
3443 * SLUB stores one object immediately after another beginning from
3444 * offset 0. In order to align the objects we have to simply size
3445 * each object to conform to the alignment.
3447 size = ALIGN(size, s->align);
3449 if (forced_order >= 0)
3450 order = forced_order;
3452 order = calculate_order(size, s->reserved);
3459 s->allocflags |= __GFP_COMP;
3461 if (s->flags & SLAB_CACHE_DMA)
3462 s->allocflags |= GFP_DMA;
3464 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3465 s->allocflags |= __GFP_RECLAIMABLE;
3468 * Determine the number of objects per slab
3470 s->oo = oo_make(order, size, s->reserved);
3471 s->min = oo_make(get_order(size), size, s->reserved);
3472 if (oo_objects(s->oo) > oo_objects(s->max))
3475 return !!oo_objects(s->oo);
3478 static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3480 s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3483 if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3484 s->reserved = sizeof(struct rcu_head);
3486 if (!calculate_sizes(s, -1))
3488 if (disable_higher_order_debug) {
3490 * Disable debugging flags that store metadata if the min slab
3493 if (get_order(s->size) > get_order(s->object_size)) {
3494 s->flags &= ~DEBUG_METADATA_FLAGS;
3496 if (!calculate_sizes(s, -1))
3501 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3502 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3503 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3504 /* Enable fast mode */
3505 s->flags |= __CMPXCHG_DOUBLE;
3509 * The larger the object size is, the more pages we want on the partial
3510 * list to avoid pounding the page allocator excessively.
3512 set_min_partial(s, ilog2(s->size) / 2);
3515 * cpu_partial determined the maximum number of objects kept in the
3516 * per cpu partial lists of a processor.
3518 * Per cpu partial lists mainly contain slabs that just have one
3519 * object freed. If they are used for allocation then they can be
3520 * filled up again with minimal effort. The slab will never hit the
3521 * per node partial lists and therefore no locking will be required.
3523 * This setting also determines
3525 * A) The number of objects from per cpu partial slabs dumped to the
3526 * per node list when we reach the limit.
3527 * B) The number of objects in cpu partial slabs to extract from the
3528 * per node list when we run out of per cpu objects. We only fetch
3529 * 50% to keep some capacity around for frees.
3531 if (!kmem_cache_has_cpu_partial(s))
3533 else if (s->size >= PAGE_SIZE)
3535 else if (s->size >= 1024)
3537 else if (s->size >= 256)
3538 s->cpu_partial = 13;
3540 s->cpu_partial = 30;
3543 s->remote_node_defrag_ratio = 1000;
3546 /* Initialize the pre-computed randomized freelist if slab is up */
3547 if (slab_state >= UP) {
3548 if (init_cache_random_seq(s))
3552 if (!init_kmem_cache_nodes(s))
3555 if (alloc_kmem_cache_cpus(s))
3558 free_kmem_cache_nodes(s);
3560 if (flags & SLAB_PANIC)
3561 panic("Cannot create slab %s size=%lu realsize=%u order=%u offset=%u flags=%lx\n",
3562 s->name, (unsigned long)s->size, s->size,
3563 oo_order(s->oo), s->offset, flags);
3567 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3570 #ifdef CONFIG_SLUB_DEBUG
3571 void *addr = page_address(page);
3573 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3574 sizeof(long), GFP_ATOMIC);
3577 slab_err(s, page, text, s->name);
3580 get_map(s, page, map);
3581 for_each_object(p, s, addr, page->objects) {
3583 if (!test_bit(slab_index(p, s, addr), map)) {
3584 pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3585 print_tracking(s, p);
3594 * Attempt to free all partial slabs on a node.
3595 * This is called from __kmem_cache_shutdown(). We must take list_lock
3596 * because sysfs file might still access partial list after the shutdowning.
3598 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3600 struct page *page, *h;
3602 BUG_ON(irqs_disabled());
3603 spin_lock_irq(&n->list_lock);
3604 list_for_each_entry_safe(page, h, &n->partial, lru) {
3606 remove_partial(n, page);
3607 discard_slab(s, page);
3609 list_slab_objects(s, page,
3610 "Objects remaining in %s on __kmem_cache_shutdown()");
3613 spin_unlock_irq(&n->list_lock);
3617 * Release all resources used by a slab cache.
3619 int __kmem_cache_shutdown(struct kmem_cache *s)
3622 struct kmem_cache_node *n;
3625 /* Attempt to free all objects */
3626 for_each_kmem_cache_node(s, node, n) {
3628 if (n->nr_partial || slabs_node(s, node))
3634 /********************************************************************
3636 *******************************************************************/
3638 static int __init setup_slub_min_order(char *str)
3640 get_option(&str, &slub_min_order);
3645 __setup("slub_min_order=", setup_slub_min_order);
3647 static int __init setup_slub_max_order(char *str)
3649 get_option(&str, &slub_max_order);
3650 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3655 __setup("slub_max_order=", setup_slub_max_order);
3657 static int __init setup_slub_min_objects(char *str)
3659 get_option(&str, &slub_min_objects);
3664 __setup("slub_min_objects=", setup_slub_min_objects);
3666 void *__kmalloc(size_t size, gfp_t flags)
3668 struct kmem_cache *s;
3671 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3672 return kmalloc_large(size, flags);
3674 s = kmalloc_slab(size, flags);
3676 if (unlikely(ZERO_OR_NULL_PTR(s)))
3679 ret = slab_alloc(s, flags, _RET_IP_);
3681 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3683 kasan_kmalloc(s, ret, size, flags);
3687 EXPORT_SYMBOL(__kmalloc);
3690 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3695 flags |= __GFP_COMP | __GFP_NOTRACK;
3696 page = alloc_pages_node(node, flags, get_order(size));
3698 ptr = page_address(page);
3700 kmalloc_large_node_hook(ptr, size, flags);
3704 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3706 struct kmem_cache *s;
3709 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3710 ret = kmalloc_large_node(size, flags, node);
3712 trace_kmalloc_node(_RET_IP_, ret,
3713 size, PAGE_SIZE << get_order(size),
3719 s = kmalloc_slab(size, flags);
3721 if (unlikely(ZERO_OR_NULL_PTR(s)))
3724 ret = slab_alloc_node(s, flags, node, _RET_IP_);
3726 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3728 kasan_kmalloc(s, ret, size, flags);
3732 EXPORT_SYMBOL(__kmalloc_node);
3735 static size_t __ksize(const void *object)
3739 if (unlikely(object == ZERO_SIZE_PTR))
3742 page = virt_to_head_page(object);
3744 if (unlikely(!PageSlab(page))) {
3745 WARN_ON(!PageCompound(page));
3746 return PAGE_SIZE << compound_order(page);
3749 return slab_ksize(page->slab_cache);
3752 size_t ksize(const void *object)
3754 size_t size = __ksize(object);
3755 /* We assume that ksize callers could use whole allocated area,
3756 * so we need to unpoison this area.
3758 kasan_unpoison_shadow(object, size);
3761 EXPORT_SYMBOL(ksize);
3763 void kfree(const void *x)
3766 void *object = (void *)x;
3768 trace_kfree(_RET_IP_, x);
3770 if (unlikely(ZERO_OR_NULL_PTR(x)))
3773 page = virt_to_head_page(x);
3774 if (unlikely(!PageSlab(page))) {
3775 BUG_ON(!PageCompound(page));
3777 __free_pages(page, compound_order(page));
3780 slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3782 EXPORT_SYMBOL(kfree);
3784 #define SHRINK_PROMOTE_MAX 32
3787 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3788 * up most to the head of the partial lists. New allocations will then
3789 * fill those up and thus they can be removed from the partial lists.
3791 * The slabs with the least items are placed last. This results in them
3792 * being allocated from last increasing the chance that the last objects
3793 * are freed in them.
3795 int __kmem_cache_shrink(struct kmem_cache *s, bool deactivate)
3799 struct kmem_cache_node *n;
3802 struct list_head discard;
3803 struct list_head promote[SHRINK_PROMOTE_MAX];
3804 unsigned long flags;
3809 * Disable empty slabs caching. Used to avoid pinning offline
3810 * memory cgroups by kmem pages that can be freed.
3816 * s->cpu_partial is checked locklessly (see put_cpu_partial),
3817 * so we have to make sure the change is visible.
3819 synchronize_sched();
3823 for_each_kmem_cache_node(s, node, n) {
3824 INIT_LIST_HEAD(&discard);
3825 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3826 INIT_LIST_HEAD(promote + i);
3828 spin_lock_irqsave(&n->list_lock, flags);
3831 * Build lists of slabs to discard or promote.
3833 * Note that concurrent frees may occur while we hold the
3834 * list_lock. page->inuse here is the upper limit.
3836 list_for_each_entry_safe(page, t, &n->partial, lru) {
3837 int free = page->objects - page->inuse;
3839 /* Do not reread page->inuse */
3842 /* We do not keep full slabs on the list */
3845 if (free == page->objects) {
3846 list_move(&page->lru, &discard);
3848 } else if (free <= SHRINK_PROMOTE_MAX)
3849 list_move(&page->lru, promote + free - 1);
3853 * Promote the slabs filled up most to the head of the
3856 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
3857 list_splice(promote + i, &n->partial);
3859 spin_unlock_irqrestore(&n->list_lock, flags);
3861 /* Release empty slabs */
3862 list_for_each_entry_safe(page, t, &discard, lru)
3863 discard_slab(s, page);
3865 if (slabs_node(s, node))
3872 static int slab_mem_going_offline_callback(void *arg)
3874 struct kmem_cache *s;
3876 mutex_lock(&slab_mutex);
3877 list_for_each_entry(s, &slab_caches, list)
3878 __kmem_cache_shrink(s, false);
3879 mutex_unlock(&slab_mutex);
3884 static void slab_mem_offline_callback(void *arg)
3886 struct kmem_cache_node *n;
3887 struct kmem_cache *s;
3888 struct memory_notify *marg = arg;
3891 offline_node = marg->status_change_nid_normal;
3894 * If the node still has available memory. we need kmem_cache_node
3897 if (offline_node < 0)
3900 mutex_lock(&slab_mutex);
3901 list_for_each_entry(s, &slab_caches, list) {
3902 n = get_node(s, offline_node);
3905 * if n->nr_slabs > 0, slabs still exist on the node
3906 * that is going down. We were unable to free them,
3907 * and offline_pages() function shouldn't call this
3908 * callback. So, we must fail.
3910 BUG_ON(slabs_node(s, offline_node));
3912 s->node[offline_node] = NULL;
3913 kmem_cache_free(kmem_cache_node, n);
3916 mutex_unlock(&slab_mutex);
3919 static int slab_mem_going_online_callback(void *arg)
3921 struct kmem_cache_node *n;
3922 struct kmem_cache *s;
3923 struct memory_notify *marg = arg;
3924 int nid = marg->status_change_nid_normal;
3928 * If the node's memory is already available, then kmem_cache_node is
3929 * already created. Nothing to do.
3935 * We are bringing a node online. No memory is available yet. We must
3936 * allocate a kmem_cache_node structure in order to bring the node
3939 mutex_lock(&slab_mutex);
3940 list_for_each_entry(s, &slab_caches, list) {
3942 * XXX: kmem_cache_alloc_node will fallback to other nodes
3943 * since memory is not yet available from the node that
3946 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3951 init_kmem_cache_node(n);
3955 mutex_unlock(&slab_mutex);
3959 static int slab_memory_callback(struct notifier_block *self,
3960 unsigned long action, void *arg)
3965 case MEM_GOING_ONLINE:
3966 ret = slab_mem_going_online_callback(arg);
3968 case MEM_GOING_OFFLINE:
3969 ret = slab_mem_going_offline_callback(arg);
3972 case MEM_CANCEL_ONLINE:
3973 slab_mem_offline_callback(arg);
3976 case MEM_CANCEL_OFFLINE:
3980 ret = notifier_from_errno(ret);
3986 static struct notifier_block slab_memory_callback_nb = {
3987 .notifier_call = slab_memory_callback,
3988 .priority = SLAB_CALLBACK_PRI,
3991 /********************************************************************
3992 * Basic setup of slabs
3993 *******************************************************************/
3996 * Used for early kmem_cache structures that were allocated using
3997 * the page allocator. Allocate them properly then fix up the pointers
3998 * that may be pointing to the wrong kmem_cache structure.
4001 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4004 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4005 struct kmem_cache_node *n;
4007 memcpy(s, static_cache, kmem_cache->object_size);
4010 * This runs very early, and only the boot processor is supposed to be
4011 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4014 __flush_cpu_slab(s, smp_processor_id());
4015 for_each_kmem_cache_node(s, node, n) {
4018 list_for_each_entry(p, &n->partial, lru)
4021 #ifdef CONFIG_SLUB_DEBUG
4022 list_for_each_entry(p, &n->full, lru)
4026 slab_init_memcg_params(s);
4027 list_add(&s->list, &slab_caches);
4031 void __init kmem_cache_init(void)
4033 static __initdata struct kmem_cache boot_kmem_cache,
4034 boot_kmem_cache_node;
4036 if (debug_guardpage_minorder())
4039 kmem_cache_node = &boot_kmem_cache_node;
4040 kmem_cache = &boot_kmem_cache;
4042 create_boot_cache(kmem_cache_node, "kmem_cache_node",
4043 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
4045 register_hotmemory_notifier(&slab_memory_callback_nb);
4047 /* Able to allocate the per node structures */
4048 slab_state = PARTIAL;
4050 create_boot_cache(kmem_cache, "kmem_cache",
4051 offsetof(struct kmem_cache, node) +
4052 nr_node_ids * sizeof(struct kmem_cache_node *),
4053 SLAB_HWCACHE_ALIGN);
4055 kmem_cache = bootstrap(&boot_kmem_cache);
4058 * Allocate kmem_cache_node properly from the kmem_cache slab.
4059 * kmem_cache_node is separately allocated so no need to
4060 * update any list pointers.
4062 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4064 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4065 setup_kmalloc_cache_index_table();
4066 create_kmalloc_caches(0);
4068 /* Setup random freelists for each cache */
4069 init_freelist_randomization();
4072 register_cpu_notifier(&slab_notifier);
4075 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
4077 slub_min_order, slub_max_order, slub_min_objects,
4078 nr_cpu_ids, nr_node_ids);
4081 void __init kmem_cache_init_late(void)
4086 __kmem_cache_alias(const char *name, size_t size, size_t align,
4087 unsigned long flags, void (*ctor)(void *))
4089 struct kmem_cache *s, *c;
4091 s = find_mergeable(size, align, flags, name, ctor);
4096 * Adjust the object sizes so that we clear
4097 * the complete object on kzalloc.
4099 s->object_size = max(s->object_size, (int)size);
4100 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
4102 for_each_memcg_cache(c, s) {
4103 c->object_size = s->object_size;
4104 c->inuse = max_t(int, c->inuse,
4105 ALIGN(size, sizeof(void *)));
4108 if (sysfs_slab_alias(s, name)) {
4117 int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
4121 err = kmem_cache_open(s, flags);
4125 /* Mutex is not taken during early boot */
4126 if (slab_state <= UP)
4129 memcg_propagate_slab_attrs(s);
4130 err = sysfs_slab_add(s);
4132 __kmem_cache_release(s);
4139 * Use the cpu notifier to insure that the cpu slabs are flushed when
4142 static int slab_cpuup_callback(struct notifier_block *nfb,
4143 unsigned long action, void *hcpu)
4145 long cpu = (long)hcpu;
4146 struct kmem_cache *s;
4147 unsigned long flags;
4150 case CPU_UP_CANCELED:
4151 case CPU_UP_CANCELED_FROZEN:
4153 case CPU_DEAD_FROZEN:
4154 mutex_lock(&slab_mutex);
4155 list_for_each_entry(s, &slab_caches, list) {
4156 local_irq_save(flags);
4157 __flush_cpu_slab(s, cpu);
4158 local_irq_restore(flags);
4160 mutex_unlock(&slab_mutex);
4168 static struct notifier_block slab_notifier = {
4169 .notifier_call = slab_cpuup_callback
4174 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4176 struct kmem_cache *s;
4179 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4180 return kmalloc_large(size, gfpflags);
4182 s = kmalloc_slab(size, gfpflags);
4184 if (unlikely(ZERO_OR_NULL_PTR(s)))
4187 ret = slab_alloc(s, gfpflags, caller);
4189 /* Honor the call site pointer we received. */
4190 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4196 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4197 int node, unsigned long caller)
4199 struct kmem_cache *s;
4202 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4203 ret = kmalloc_large_node(size, gfpflags, node);
4205 trace_kmalloc_node(caller, ret,
4206 size, PAGE_SIZE << get_order(size),
4212 s = kmalloc_slab(size, gfpflags);
4214 if (unlikely(ZERO_OR_NULL_PTR(s)))
4217 ret = slab_alloc_node(s, gfpflags, node, caller);
4219 /* Honor the call site pointer we received. */
4220 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4227 static int count_inuse(struct page *page)
4232 static int count_total(struct page *page)
4234 return page->objects;
4238 #ifdef CONFIG_SLUB_DEBUG
4239 static int validate_slab(struct kmem_cache *s, struct page *page,
4243 void *addr = page_address(page);
4245 if (!check_slab(s, page) ||
4246 !on_freelist(s, page, NULL))
4249 /* Now we know that a valid freelist exists */
4250 bitmap_zero(map, page->objects);
4252 get_map(s, page, map);
4253 for_each_object(p, s, addr, page->objects) {
4254 if (test_bit(slab_index(p, s, addr), map))
4255 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4259 for_each_object(p, s, addr, page->objects)
4260 if (!test_bit(slab_index(p, s, addr), map))
4261 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4266 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4270 validate_slab(s, page, map);
4274 static int validate_slab_node(struct kmem_cache *s,
4275 struct kmem_cache_node *n, unsigned long *map)
4277 unsigned long count = 0;
4279 unsigned long flags;
4281 spin_lock_irqsave(&n->list_lock, flags);
4283 list_for_each_entry(page, &n->partial, lru) {
4284 validate_slab_slab(s, page, map);
4287 if (count != n->nr_partial)
4288 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4289 s->name, count, n->nr_partial);
4291 if (!(s->flags & SLAB_STORE_USER))
4294 list_for_each_entry(page, &n->full, lru) {
4295 validate_slab_slab(s, page, map);
4298 if (count != atomic_long_read(&n->nr_slabs))
4299 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4300 s->name, count, atomic_long_read(&n->nr_slabs));
4303 spin_unlock_irqrestore(&n->list_lock, flags);
4307 static long validate_slab_cache(struct kmem_cache *s)
4310 unsigned long count = 0;
4311 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4312 sizeof(unsigned long), GFP_KERNEL);
4313 struct kmem_cache_node *n;
4319 for_each_kmem_cache_node(s, node, n)
4320 count += validate_slab_node(s, n, map);
4325 * Generate lists of code addresses where slabcache objects are allocated
4330 unsigned long count;
4337 DECLARE_BITMAP(cpus, NR_CPUS);
4343 unsigned long count;
4344 struct location *loc;
4347 static void free_loc_track(struct loc_track *t)
4350 free_pages((unsigned long)t->loc,
4351 get_order(sizeof(struct location) * t->max));
4354 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4359 order = get_order(sizeof(struct location) * max);
4361 l = (void *)__get_free_pages(flags, order);
4366 memcpy(l, t->loc, sizeof(struct location) * t->count);
4374 static int add_location(struct loc_track *t, struct kmem_cache *s,
4375 const struct track *track)
4377 long start, end, pos;
4379 unsigned long caddr;
4380 unsigned long age = jiffies - track->when;
4386 pos = start + (end - start + 1) / 2;
4389 * There is nothing at "end". If we end up there
4390 * we need to add something to before end.
4395 caddr = t->loc[pos].addr;
4396 if (track->addr == caddr) {
4402 if (age < l->min_time)
4404 if (age > l->max_time)
4407 if (track->pid < l->min_pid)
4408 l->min_pid = track->pid;
4409 if (track->pid > l->max_pid)
4410 l->max_pid = track->pid;
4412 cpumask_set_cpu(track->cpu,
4413 to_cpumask(l->cpus));
4415 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4419 if (track->addr < caddr)
4426 * Not found. Insert new tracking element.
4428 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4434 (t->count - pos) * sizeof(struct location));
4437 l->addr = track->addr;
4441 l->min_pid = track->pid;
4442 l->max_pid = track->pid;
4443 cpumask_clear(to_cpumask(l->cpus));
4444 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4445 nodes_clear(l->nodes);
4446 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4450 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4451 struct page *page, enum track_item alloc,
4454 void *addr = page_address(page);
4457 bitmap_zero(map, page->objects);
4458 get_map(s, page, map);
4460 for_each_object(p, s, addr, page->objects)
4461 if (!test_bit(slab_index(p, s, addr), map))
4462 add_location(t, s, get_track(s, p, alloc));
4465 static int list_locations(struct kmem_cache *s, char *buf,
4466 enum track_item alloc)
4470 struct loc_track t = { 0, 0, NULL };
4472 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4473 sizeof(unsigned long), GFP_KERNEL);
4474 struct kmem_cache_node *n;
4476 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4479 return sprintf(buf, "Out of memory\n");
4481 /* Push back cpu slabs */
4484 for_each_kmem_cache_node(s, node, n) {
4485 unsigned long flags;
4488 if (!atomic_long_read(&n->nr_slabs))
4491 spin_lock_irqsave(&n->list_lock, flags);
4492 list_for_each_entry(page, &n->partial, lru)
4493 process_slab(&t, s, page, alloc, map);
4494 list_for_each_entry(page, &n->full, lru)
4495 process_slab(&t, s, page, alloc, map);
4496 spin_unlock_irqrestore(&n->list_lock, flags);
4499 for (i = 0; i < t.count; i++) {
4500 struct location *l = &t.loc[i];
4502 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4504 len += sprintf(buf + len, "%7ld ", l->count);
4507 len += sprintf(buf + len, "%pS", (void *)l->addr);
4509 len += sprintf(buf + len, "<not-available>");
4511 if (l->sum_time != l->min_time) {
4512 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4514 (long)div_u64(l->sum_time, l->count),
4517 len += sprintf(buf + len, " age=%ld",
4520 if (l->min_pid != l->max_pid)
4521 len += sprintf(buf + len, " pid=%ld-%ld",
4522 l->min_pid, l->max_pid);
4524 len += sprintf(buf + len, " pid=%ld",
4527 if (num_online_cpus() > 1 &&
4528 !cpumask_empty(to_cpumask(l->cpus)) &&
4529 len < PAGE_SIZE - 60)
4530 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4532 cpumask_pr_args(to_cpumask(l->cpus)));
4534 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4535 len < PAGE_SIZE - 60)
4536 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4538 nodemask_pr_args(&l->nodes));
4540 len += sprintf(buf + len, "\n");
4546 len += sprintf(buf, "No data\n");
4551 #ifdef SLUB_RESILIENCY_TEST
4552 static void __init resiliency_test(void)
4556 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4558 pr_err("SLUB resiliency testing\n");
4559 pr_err("-----------------------\n");
4560 pr_err("A. Corruption after allocation\n");
4562 p = kzalloc(16, GFP_KERNEL);
4564 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4567 validate_slab_cache(kmalloc_caches[4]);
4569 /* Hmmm... The next two are dangerous */
4570 p = kzalloc(32, GFP_KERNEL);
4571 p[32 + sizeof(void *)] = 0x34;
4572 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4574 pr_err("If allocated object is overwritten then not detectable\n\n");
4576 validate_slab_cache(kmalloc_caches[5]);
4577 p = kzalloc(64, GFP_KERNEL);
4578 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4580 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4582 pr_err("If allocated object is overwritten then not detectable\n\n");
4583 validate_slab_cache(kmalloc_caches[6]);
4585 pr_err("\nB. Corruption after free\n");
4586 p = kzalloc(128, GFP_KERNEL);
4589 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4590 validate_slab_cache(kmalloc_caches[7]);
4592 p = kzalloc(256, GFP_KERNEL);
4595 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4596 validate_slab_cache(kmalloc_caches[8]);
4598 p = kzalloc(512, GFP_KERNEL);
4601 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4602 validate_slab_cache(kmalloc_caches[9]);
4606 static void resiliency_test(void) {};
4611 enum slab_stat_type {
4612 SL_ALL, /* All slabs */
4613 SL_PARTIAL, /* Only partially allocated slabs */
4614 SL_CPU, /* Only slabs used for cpu caches */
4615 SL_OBJECTS, /* Determine allocated objects not slabs */
4616 SL_TOTAL /* Determine object capacity not slabs */
4619 #define SO_ALL (1 << SL_ALL)
4620 #define SO_PARTIAL (1 << SL_PARTIAL)
4621 #define SO_CPU (1 << SL_CPU)
4622 #define SO_OBJECTS (1 << SL_OBJECTS)
4623 #define SO_TOTAL (1 << SL_TOTAL)
4625 static ssize_t show_slab_objects(struct kmem_cache *s,
4626 char *buf, unsigned long flags)
4628 unsigned long total = 0;
4631 unsigned long *nodes;
4633 nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4637 if (flags & SO_CPU) {
4640 for_each_possible_cpu(cpu) {
4641 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4646 page = READ_ONCE(c->page);
4650 node = page_to_nid(page);
4651 if (flags & SO_TOTAL)
4653 else if (flags & SO_OBJECTS)
4661 page = READ_ONCE(c->partial);
4663 node = page_to_nid(page);
4664 if (flags & SO_TOTAL)
4666 else if (flags & SO_OBJECTS)
4677 #ifdef CONFIG_SLUB_DEBUG
4678 if (flags & SO_ALL) {
4679 struct kmem_cache_node *n;
4681 for_each_kmem_cache_node(s, node, n) {
4683 if (flags & SO_TOTAL)
4684 x = atomic_long_read(&n->total_objects);
4685 else if (flags & SO_OBJECTS)
4686 x = atomic_long_read(&n->total_objects) -
4687 count_partial(n, count_free);
4689 x = atomic_long_read(&n->nr_slabs);
4696 if (flags & SO_PARTIAL) {
4697 struct kmem_cache_node *n;
4699 for_each_kmem_cache_node(s, node, n) {
4700 if (flags & SO_TOTAL)
4701 x = count_partial(n, count_total);
4702 else if (flags & SO_OBJECTS)
4703 x = count_partial(n, count_inuse);
4710 x = sprintf(buf, "%lu", total);
4712 for (node = 0; node < nr_node_ids; node++)
4714 x += sprintf(buf + x, " N%d=%lu",
4719 return x + sprintf(buf + x, "\n");
4722 #ifdef CONFIG_SLUB_DEBUG
4723 static int any_slab_objects(struct kmem_cache *s)
4726 struct kmem_cache_node *n;
4728 for_each_kmem_cache_node(s, node, n)
4729 if (atomic_long_read(&n->total_objects))
4736 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4737 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4739 struct slab_attribute {
4740 struct attribute attr;
4741 ssize_t (*show)(struct kmem_cache *s, char *buf);
4742 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4745 #define SLAB_ATTR_RO(_name) \
4746 static struct slab_attribute _name##_attr = \
4747 __ATTR(_name, 0400, _name##_show, NULL)
4749 #define SLAB_ATTR(_name) \
4750 static struct slab_attribute _name##_attr = \
4751 __ATTR(_name, 0600, _name##_show, _name##_store)
4753 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4755 return sprintf(buf, "%d\n", s->size);
4757 SLAB_ATTR_RO(slab_size);
4759 static ssize_t align_show(struct kmem_cache *s, char *buf)
4761 return sprintf(buf, "%d\n", s->align);
4763 SLAB_ATTR_RO(align);
4765 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4767 return sprintf(buf, "%d\n", s->object_size);
4769 SLAB_ATTR_RO(object_size);
4771 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4773 return sprintf(buf, "%d\n", oo_objects(s->oo));
4775 SLAB_ATTR_RO(objs_per_slab);
4777 static ssize_t order_store(struct kmem_cache *s,
4778 const char *buf, size_t length)
4780 unsigned long order;
4783 err = kstrtoul(buf, 10, &order);
4787 if (order > slub_max_order || order < slub_min_order)
4790 calculate_sizes(s, order);
4794 static ssize_t order_show(struct kmem_cache *s, char *buf)
4796 return sprintf(buf, "%d\n", oo_order(s->oo));
4800 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4802 return sprintf(buf, "%lu\n", s->min_partial);
4805 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4811 err = kstrtoul(buf, 10, &min);
4815 set_min_partial(s, min);
4818 SLAB_ATTR(min_partial);
4820 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4822 return sprintf(buf, "%u\n", s->cpu_partial);
4825 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4828 unsigned long objects;
4831 err = kstrtoul(buf, 10, &objects);
4834 if (objects && !kmem_cache_has_cpu_partial(s))
4837 s->cpu_partial = objects;
4841 SLAB_ATTR(cpu_partial);
4843 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4847 return sprintf(buf, "%pS\n", s->ctor);
4851 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4853 return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
4855 SLAB_ATTR_RO(aliases);
4857 static ssize_t partial_show(struct kmem_cache *s, char *buf)
4859 return show_slab_objects(s, buf, SO_PARTIAL);
4861 SLAB_ATTR_RO(partial);
4863 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4865 return show_slab_objects(s, buf, SO_CPU);
4867 SLAB_ATTR_RO(cpu_slabs);
4869 static ssize_t objects_show(struct kmem_cache *s, char *buf)
4871 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4873 SLAB_ATTR_RO(objects);
4875 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4877 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4879 SLAB_ATTR_RO(objects_partial);
4881 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4888 for_each_online_cpu(cpu) {
4889 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4892 pages += page->pages;
4893 objects += page->pobjects;
4897 len = sprintf(buf, "%d(%d)", objects, pages);
4900 for_each_online_cpu(cpu) {
4901 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4903 if (page && len < PAGE_SIZE - 20)
4904 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4905 page->pobjects, page->pages);
4908 return len + sprintf(buf + len, "\n");
4910 SLAB_ATTR_RO(slabs_cpu_partial);
4912 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4914 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4917 static ssize_t reclaim_account_store(struct kmem_cache *s,
4918 const char *buf, size_t length)
4920 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4922 s->flags |= SLAB_RECLAIM_ACCOUNT;
4925 SLAB_ATTR(reclaim_account);
4927 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4929 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4931 SLAB_ATTR_RO(hwcache_align);
4933 #ifdef CONFIG_ZONE_DMA
4934 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4936 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4938 SLAB_ATTR_RO(cache_dma);
4941 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4943 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4945 SLAB_ATTR_RO(destroy_by_rcu);
4947 static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4949 return sprintf(buf, "%d\n", s->reserved);
4951 SLAB_ATTR_RO(reserved);
4953 #ifdef CONFIG_SLUB_DEBUG
4954 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4956 return show_slab_objects(s, buf, SO_ALL);
4958 SLAB_ATTR_RO(slabs);
4960 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4962 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4964 SLAB_ATTR_RO(total_objects);
4966 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4968 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
4971 static ssize_t sanity_checks_store(struct kmem_cache *s,
4972 const char *buf, size_t length)
4974 s->flags &= ~SLAB_CONSISTENCY_CHECKS;
4975 if (buf[0] == '1') {
4976 s->flags &= ~__CMPXCHG_DOUBLE;
4977 s->flags |= SLAB_CONSISTENCY_CHECKS;
4981 SLAB_ATTR(sanity_checks);
4983 static ssize_t trace_show(struct kmem_cache *s, char *buf)
4985 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4988 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4992 * Tracing a merged cache is going to give confusing results
4993 * as well as cause other issues like converting a mergeable
4994 * cache into an umergeable one.
4996 if (s->refcount > 1)
4999 s->flags &= ~SLAB_TRACE;
5000 if (buf[0] == '1') {
5001 s->flags &= ~__CMPXCHG_DOUBLE;
5002 s->flags |= SLAB_TRACE;
5008 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5010 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5013 static ssize_t red_zone_store(struct kmem_cache *s,
5014 const char *buf, size_t length)
5016 if (any_slab_objects(s))
5019 s->flags &= ~SLAB_RED_ZONE;
5020 if (buf[0] == '1') {
5021 s->flags |= SLAB_RED_ZONE;
5023 calculate_sizes(s, -1);
5026 SLAB_ATTR(red_zone);
5028 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5030 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5033 static ssize_t poison_store(struct kmem_cache *s,
5034 const char *buf, size_t length)
5036 if (any_slab_objects(s))
5039 s->flags &= ~SLAB_POISON;
5040 if (buf[0] == '1') {
5041 s->flags |= SLAB_POISON;
5043 calculate_sizes(s, -1);
5048 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5050 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5053 static ssize_t store_user_store(struct kmem_cache *s,
5054 const char *buf, size_t length)
5056 if (any_slab_objects(s))
5059 s->flags &= ~SLAB_STORE_USER;
5060 if (buf[0] == '1') {
5061 s->flags &= ~__CMPXCHG_DOUBLE;
5062 s->flags |= SLAB_STORE_USER;
5064 calculate_sizes(s, -1);
5067 SLAB_ATTR(store_user);
5069 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5074 static ssize_t validate_store(struct kmem_cache *s,
5075 const char *buf, size_t length)
5079 if (buf[0] == '1') {
5080 ret = validate_slab_cache(s);
5086 SLAB_ATTR(validate);
5088 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5090 if (!(s->flags & SLAB_STORE_USER))
5092 return list_locations(s, buf, TRACK_ALLOC);
5094 SLAB_ATTR_RO(alloc_calls);
5096 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5098 if (!(s->flags & SLAB_STORE_USER))
5100 return list_locations(s, buf, TRACK_FREE);
5102 SLAB_ATTR_RO(free_calls);
5103 #endif /* CONFIG_SLUB_DEBUG */
5105 #ifdef CONFIG_FAILSLAB
5106 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5108 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5111 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5114 if (s->refcount > 1)
5117 s->flags &= ~SLAB_FAILSLAB;
5119 s->flags |= SLAB_FAILSLAB;
5122 SLAB_ATTR(failslab);
5125 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5130 static ssize_t shrink_store(struct kmem_cache *s,
5131 const char *buf, size_t length)
5134 kmem_cache_shrink(s);
5142 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5144 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
5147 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5148 const char *buf, size_t length)
5150 unsigned long ratio;
5153 err = kstrtoul(buf, 10, &ratio);
5158 s->remote_node_defrag_ratio = ratio * 10;
5162 SLAB_ATTR(remote_node_defrag_ratio);
5165 #ifdef CONFIG_SLUB_STATS
5166 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5168 unsigned long sum = 0;
5171 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5176 for_each_online_cpu(cpu) {
5177 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5183 len = sprintf(buf, "%lu", sum);
5186 for_each_online_cpu(cpu) {
5187 if (data[cpu] && len < PAGE_SIZE - 20)
5188 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5192 return len + sprintf(buf + len, "\n");
5195 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5199 for_each_online_cpu(cpu)
5200 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5203 #define STAT_ATTR(si, text) \
5204 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5206 return show_stat(s, buf, si); \
5208 static ssize_t text##_store(struct kmem_cache *s, \
5209 const char *buf, size_t length) \
5211 if (buf[0] != '0') \
5213 clear_stat(s, si); \
5218 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5219 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5220 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5221 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5222 STAT_ATTR(FREE_FROZEN, free_frozen);
5223 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5224 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5225 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5226 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5227 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5228 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5229 STAT_ATTR(FREE_SLAB, free_slab);
5230 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5231 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5232 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5233 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5234 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5235 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5236 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5237 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5238 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5239 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5240 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5241 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5242 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5243 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5246 static struct attribute *slab_attrs[] = {
5247 &slab_size_attr.attr,
5248 &object_size_attr.attr,
5249 &objs_per_slab_attr.attr,
5251 &min_partial_attr.attr,
5252 &cpu_partial_attr.attr,
5254 &objects_partial_attr.attr,
5256 &cpu_slabs_attr.attr,
5260 &hwcache_align_attr.attr,
5261 &reclaim_account_attr.attr,
5262 &destroy_by_rcu_attr.attr,
5264 &reserved_attr.attr,
5265 &slabs_cpu_partial_attr.attr,
5266 #ifdef CONFIG_SLUB_DEBUG
5267 &total_objects_attr.attr,
5269 &sanity_checks_attr.attr,
5271 &red_zone_attr.attr,
5273 &store_user_attr.attr,
5274 &validate_attr.attr,
5275 &alloc_calls_attr.attr,
5276 &free_calls_attr.attr,
5278 #ifdef CONFIG_ZONE_DMA
5279 &cache_dma_attr.attr,
5282 &remote_node_defrag_ratio_attr.attr,
5284 #ifdef CONFIG_SLUB_STATS
5285 &alloc_fastpath_attr.attr,
5286 &alloc_slowpath_attr.attr,
5287 &free_fastpath_attr.attr,
5288 &free_slowpath_attr.attr,
5289 &free_frozen_attr.attr,
5290 &free_add_partial_attr.attr,
5291 &free_remove_partial_attr.attr,
5292 &alloc_from_partial_attr.attr,
5293 &alloc_slab_attr.attr,
5294 &alloc_refill_attr.attr,
5295 &alloc_node_mismatch_attr.attr,
5296 &free_slab_attr.attr,
5297 &cpuslab_flush_attr.attr,
5298 &deactivate_full_attr.attr,
5299 &deactivate_empty_attr.attr,
5300 &deactivate_to_head_attr.attr,
5301 &deactivate_to_tail_attr.attr,
5302 &deactivate_remote_frees_attr.attr,
5303 &deactivate_bypass_attr.attr,
5304 &order_fallback_attr.attr,
5305 &cmpxchg_double_fail_attr.attr,
5306 &cmpxchg_double_cpu_fail_attr.attr,
5307 &cpu_partial_alloc_attr.attr,
5308 &cpu_partial_free_attr.attr,
5309 &cpu_partial_node_attr.attr,
5310 &cpu_partial_drain_attr.attr,
5312 #ifdef CONFIG_FAILSLAB
5313 &failslab_attr.attr,
5319 static struct attribute_group slab_attr_group = {
5320 .attrs = slab_attrs,
5323 static ssize_t slab_attr_show(struct kobject *kobj,
5324 struct attribute *attr,
5327 struct slab_attribute *attribute;
5328 struct kmem_cache *s;
5331 attribute = to_slab_attr(attr);
5334 if (!attribute->show)
5337 err = attribute->show(s, buf);
5342 static ssize_t slab_attr_store(struct kobject *kobj,
5343 struct attribute *attr,
5344 const char *buf, size_t len)
5346 struct slab_attribute *attribute;
5347 struct kmem_cache *s;
5350 attribute = to_slab_attr(attr);
5353 if (!attribute->store)
5356 err = attribute->store(s, buf, len);
5358 if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5359 struct kmem_cache *c;
5361 mutex_lock(&slab_mutex);
5362 if (s->max_attr_size < len)
5363 s->max_attr_size = len;
5366 * This is a best effort propagation, so this function's return
5367 * value will be determined by the parent cache only. This is
5368 * basically because not all attributes will have a well
5369 * defined semantics for rollbacks - most of the actions will
5370 * have permanent effects.
5372 * Returning the error value of any of the children that fail
5373 * is not 100 % defined, in the sense that users seeing the
5374 * error code won't be able to know anything about the state of
5377 * Only returning the error code for the parent cache at least
5378 * has well defined semantics. The cache being written to
5379 * directly either failed or succeeded, in which case we loop
5380 * through the descendants with best-effort propagation.
5382 for_each_memcg_cache(c, s)
5383 attribute->store(c, buf, len);
5384 mutex_unlock(&slab_mutex);
5390 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5394 char *buffer = NULL;
5395 struct kmem_cache *root_cache;
5397 if (is_root_cache(s))
5400 root_cache = s->memcg_params.root_cache;
5403 * This mean this cache had no attribute written. Therefore, no point
5404 * in copying default values around
5406 if (!root_cache->max_attr_size)
5409 for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5412 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5414 if (!attr || !attr->store || !attr->show)
5418 * It is really bad that we have to allocate here, so we will
5419 * do it only as a fallback. If we actually allocate, though,
5420 * we can just use the allocated buffer until the end.
5422 * Most of the slub attributes will tend to be very small in
5423 * size, but sysfs allows buffers up to a page, so they can
5424 * theoretically happen.
5428 else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5431 buffer = (char *) get_zeroed_page(GFP_KERNEL);
5432 if (WARN_ON(!buffer))
5437 attr->show(root_cache, buf);
5438 attr->store(s, buf, strlen(buf));
5442 free_page((unsigned long)buffer);
5446 static void kmem_cache_release(struct kobject *k)
5448 slab_kmem_cache_release(to_slab(k));
5451 static const struct sysfs_ops slab_sysfs_ops = {
5452 .show = slab_attr_show,
5453 .store = slab_attr_store,
5456 static struct kobj_type slab_ktype = {
5457 .sysfs_ops = &slab_sysfs_ops,
5458 .release = kmem_cache_release,
5461 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5463 struct kobj_type *ktype = get_ktype(kobj);
5465 if (ktype == &slab_ktype)
5470 static const struct kset_uevent_ops slab_uevent_ops = {
5471 .filter = uevent_filter,
5474 static struct kset *slab_kset;
5476 static inline struct kset *cache_kset(struct kmem_cache *s)
5479 if (!is_root_cache(s))
5480 return s->memcg_params.root_cache->memcg_kset;
5485 #define ID_STR_LENGTH 64
5487 /* Create a unique string id for a slab cache:
5489 * Format :[flags-]size
5491 static char *create_unique_id(struct kmem_cache *s)
5493 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5500 * First flags affecting slabcache operations. We will only
5501 * get here for aliasable slabs so we do not need to support
5502 * too many flags. The flags here must cover all flags that
5503 * are matched during merging to guarantee that the id is
5506 if (s->flags & SLAB_CACHE_DMA)
5508 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5510 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5512 if (!(s->flags & SLAB_NOTRACK))
5514 if (s->flags & SLAB_ACCOUNT)
5518 p += sprintf(p, "%07d", s->size);
5520 BUG_ON(p > name + ID_STR_LENGTH - 1);
5524 static int sysfs_slab_add(struct kmem_cache *s)
5528 int unmergeable = slab_unmergeable(s);
5532 * Slabcache can never be merged so we can use the name proper.
5533 * This is typically the case for debug situations. In that
5534 * case we can catch duplicate names easily.
5536 sysfs_remove_link(&slab_kset->kobj, s->name);
5540 * Create a unique name for the slab as a target
5543 name = create_unique_id(s);
5546 s->kobj.kset = cache_kset(s);
5547 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5551 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5556 if (is_root_cache(s)) {
5557 s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5558 if (!s->memcg_kset) {
5565 kobject_uevent(&s->kobj, KOBJ_ADD);
5567 /* Setup first alias */
5568 sysfs_slab_alias(s, s->name);
5575 kobject_del(&s->kobj);
5579 void sysfs_slab_remove(struct kmem_cache *s)
5581 if (slab_state < FULL)
5583 * Sysfs has not been setup yet so no need to remove the
5589 kset_unregister(s->memcg_kset);
5591 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5592 kobject_del(&s->kobj);
5593 kobject_put(&s->kobj);
5597 * Need to buffer aliases during bootup until sysfs becomes
5598 * available lest we lose that information.
5600 struct saved_alias {
5601 struct kmem_cache *s;
5603 struct saved_alias *next;
5606 static struct saved_alias *alias_list;
5608 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5610 struct saved_alias *al;
5612 if (slab_state == FULL) {
5614 * If we have a leftover link then remove it.
5616 sysfs_remove_link(&slab_kset->kobj, name);
5617 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5620 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5626 al->next = alias_list;
5631 static int __init slab_sysfs_init(void)
5633 struct kmem_cache *s;
5636 mutex_lock(&slab_mutex);
5638 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5640 mutex_unlock(&slab_mutex);
5641 pr_err("Cannot register slab subsystem.\n");
5647 list_for_each_entry(s, &slab_caches, list) {
5648 err = sysfs_slab_add(s);
5650 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5654 while (alias_list) {
5655 struct saved_alias *al = alias_list;
5657 alias_list = alias_list->next;
5658 err = sysfs_slab_alias(al->s, al->name);
5660 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5665 mutex_unlock(&slab_mutex);
5670 __initcall(slab_sysfs_init);
5671 #endif /* CONFIG_SYSFS */
5674 * The /proc/slabinfo ABI
5676 #ifdef CONFIG_SLABINFO
5677 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5679 unsigned long nr_slabs = 0;
5680 unsigned long nr_objs = 0;
5681 unsigned long nr_free = 0;
5683 struct kmem_cache_node *n;
5685 for_each_kmem_cache_node(s, node, n) {
5686 nr_slabs += node_nr_slabs(n);
5687 nr_objs += node_nr_objs(n);
5688 nr_free += count_partial(n, count_free);
5691 sinfo->active_objs = nr_objs - nr_free;
5692 sinfo->num_objs = nr_objs;
5693 sinfo->active_slabs = nr_slabs;
5694 sinfo->num_slabs = nr_slabs;
5695 sinfo->objects_per_slab = oo_objects(s->oo);
5696 sinfo->cache_order = oo_order(s->oo);
5699 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5703 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5704 size_t count, loff_t *ppos)
5708 #endif /* CONFIG_SLABINFO */