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 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;
458 static int slub_debug;
461 static char *slub_debug_slabs;
462 static int disable_higher_order_debug;
465 * slub is about to manipulate internal object metadata. This memory lies
466 * outside the range of the allocated object, so accessing it would normally
467 * be reported by kasan as a bounds error. metadata_access_enable() is used
468 * to tell kasan that these accesses are OK.
470 static inline void metadata_access_enable(void)
472 kasan_disable_current();
475 static inline void metadata_access_disable(void)
477 kasan_enable_current();
484 /* Verify that a pointer has an address that is valid within a slab page */
485 static inline int check_valid_pointer(struct kmem_cache *s,
486 struct page *page, void *object)
493 base = page_address(page);
494 object = restore_red_left(s, object);
495 if (object < base || object >= base + page->objects * s->size ||
496 (object - base) % s->size) {
503 static void print_section(char *text, u8 *addr, unsigned int length)
505 metadata_access_enable();
506 print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
508 metadata_access_disable();
511 static struct track *get_track(struct kmem_cache *s, void *object,
512 enum track_item alloc)
517 p = object + s->offset + sizeof(void *);
519 p = object + s->inuse;
524 static void set_track(struct kmem_cache *s, void *object,
525 enum track_item alloc, unsigned long addr)
527 struct track *p = get_track(s, object, alloc);
530 #ifdef CONFIG_STACKTRACE
531 struct stack_trace trace;
534 trace.nr_entries = 0;
535 trace.max_entries = TRACK_ADDRS_COUNT;
536 trace.entries = p->addrs;
538 metadata_access_enable();
539 save_stack_trace(&trace);
540 metadata_access_disable();
542 /* See rant in lockdep.c */
543 if (trace.nr_entries != 0 &&
544 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
547 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
551 p->cpu = smp_processor_id();
552 p->pid = current->pid;
555 memset(p, 0, sizeof(struct track));
558 static void init_tracking(struct kmem_cache *s, void *object)
560 if (!(s->flags & SLAB_STORE_USER))
563 set_track(s, object, TRACK_FREE, 0UL);
564 set_track(s, object, TRACK_ALLOC, 0UL);
567 static void print_track(const char *s, struct track *t)
572 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
573 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
574 #ifdef CONFIG_STACKTRACE
577 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
579 pr_err("\t%pS\n", (void *)t->addrs[i]);
586 static void print_tracking(struct kmem_cache *s, void *object)
588 if (!(s->flags & SLAB_STORE_USER))
591 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
592 print_track("Freed", get_track(s, object, TRACK_FREE));
595 static void print_page_info(struct page *page)
597 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
598 page, page->objects, page->inuse, page->freelist, page->flags);
602 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
604 struct va_format vaf;
610 pr_err("=============================================================================\n");
611 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
612 pr_err("-----------------------------------------------------------------------------\n\n");
614 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
618 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
620 struct va_format vaf;
626 pr_err("FIX %s: %pV\n", s->name, &vaf);
630 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
632 unsigned int off; /* Offset of last byte */
633 u8 *addr = page_address(page);
635 print_tracking(s, p);
637 print_page_info(page);
639 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
640 p, p - addr, get_freepointer(s, p));
642 if (s->flags & SLAB_RED_ZONE)
643 print_section("Redzone ", p - s->red_left_pad, s->red_left_pad);
644 else if (p > addr + 16)
645 print_section("Bytes b4 ", p - 16, 16);
647 print_section("Object ", p, min_t(unsigned long, s->object_size,
649 if (s->flags & SLAB_RED_ZONE)
650 print_section("Redzone ", p + s->object_size,
651 s->inuse - s->object_size);
654 off = s->offset + sizeof(void *);
658 if (s->flags & SLAB_STORE_USER)
659 off += 2 * sizeof(struct track);
661 off += kasan_metadata_size(s);
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 off += kasan_metadata_size(s);
792 if (size_from_object(s) == off)
795 return check_bytes_and_report(s, page, p, "Object padding",
796 p + off, POISON_INUSE, size_from_object(s) - off);
799 /* Check the pad bytes at the end of a slab page */
800 static int slab_pad_check(struct kmem_cache *s, struct page *page)
808 if (!(s->flags & SLAB_POISON))
811 start = page_address(page);
812 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
813 end = start + length;
814 remainder = length % s->size;
818 metadata_access_enable();
819 fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
820 metadata_access_disable();
823 while (end > fault && end[-1] == POISON_INUSE)
826 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
827 print_section("Padding ", end - remainder, remainder);
829 restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
833 static int check_object(struct kmem_cache *s, struct page *page,
834 void *object, u8 val)
837 u8 *endobject = object + s->object_size;
839 if (s->flags & SLAB_RED_ZONE) {
840 if (!check_bytes_and_report(s, page, object, "Redzone",
841 object - s->red_left_pad, val, s->red_left_pad))
844 if (!check_bytes_and_report(s, page, object, "Redzone",
845 endobject, val, s->inuse - s->object_size))
848 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
849 check_bytes_and_report(s, page, p, "Alignment padding",
850 endobject, POISON_INUSE,
851 s->inuse - s->object_size);
855 if (s->flags & SLAB_POISON) {
856 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
857 (!check_bytes_and_report(s, page, p, "Poison", p,
858 POISON_FREE, s->object_size - 1) ||
859 !check_bytes_and_report(s, page, p, "Poison",
860 p + s->object_size - 1, POISON_END, 1)))
863 * check_pad_bytes cleans up on its own.
865 check_pad_bytes(s, page, p);
868 if (!s->offset && val == SLUB_RED_ACTIVE)
870 * Object and freepointer overlap. Cannot check
871 * freepointer while object is allocated.
875 /* Check free pointer validity */
876 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
877 object_err(s, page, p, "Freepointer corrupt");
879 * No choice but to zap it and thus lose the remainder
880 * of the free objects in this slab. May cause
881 * another error because the object count is now wrong.
883 set_freepointer(s, p, NULL);
889 static int check_slab(struct kmem_cache *s, struct page *page)
893 VM_BUG_ON(!irqs_disabled());
895 if (!PageSlab(page)) {
896 slab_err(s, page, "Not a valid slab page");
900 maxobj = order_objects(compound_order(page), s->size, s->reserved);
901 if (page->objects > maxobj) {
902 slab_err(s, page, "objects %u > max %u",
903 page->objects, maxobj);
906 if (page->inuse > page->objects) {
907 slab_err(s, page, "inuse %u > max %u",
908 page->inuse, page->objects);
911 /* Slab_pad_check fixes things up after itself */
912 slab_pad_check(s, page);
917 * Determine if a certain object on a page is on the freelist. Must hold the
918 * slab lock to guarantee that the chains are in a consistent state.
920 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
928 while (fp && nr <= page->objects) {
931 if (!check_valid_pointer(s, page, fp)) {
933 object_err(s, page, object,
934 "Freechain corrupt");
935 set_freepointer(s, object, NULL);
937 slab_err(s, page, "Freepointer corrupt");
938 page->freelist = NULL;
939 page->inuse = page->objects;
940 slab_fix(s, "Freelist cleared");
946 fp = get_freepointer(s, object);
950 max_objects = order_objects(compound_order(page), s->size, s->reserved);
951 if (max_objects > MAX_OBJS_PER_PAGE)
952 max_objects = MAX_OBJS_PER_PAGE;
954 if (page->objects != max_objects) {
955 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
956 page->objects, max_objects);
957 page->objects = max_objects;
958 slab_fix(s, "Number of objects adjusted.");
960 if (page->inuse != page->objects - nr) {
961 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
962 page->inuse, page->objects - nr);
963 page->inuse = page->objects - nr;
964 slab_fix(s, "Object count adjusted.");
966 return search == NULL;
969 static void trace(struct kmem_cache *s, struct page *page, void *object,
972 if (s->flags & SLAB_TRACE) {
973 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
975 alloc ? "alloc" : "free",
980 print_section("Object ", (void *)object,
988 * Tracking of fully allocated slabs for debugging purposes.
990 static void add_full(struct kmem_cache *s,
991 struct kmem_cache_node *n, struct page *page)
993 if (!(s->flags & SLAB_STORE_USER))
996 lockdep_assert_held(&n->list_lock);
997 list_add(&page->lru, &n->full);
1000 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1002 if (!(s->flags & SLAB_STORE_USER))
1005 lockdep_assert_held(&n->list_lock);
1006 list_del(&page->lru);
1009 /* Tracking of the number of slabs for debugging purposes */
1010 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1012 struct kmem_cache_node *n = get_node(s, node);
1014 return atomic_long_read(&n->nr_slabs);
1017 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1019 return atomic_long_read(&n->nr_slabs);
1022 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1024 struct kmem_cache_node *n = get_node(s, node);
1027 * May be called early in order to allocate a slab for the
1028 * kmem_cache_node structure. Solve the chicken-egg
1029 * dilemma by deferring the increment of the count during
1030 * bootstrap (see early_kmem_cache_node_alloc).
1033 atomic_long_inc(&n->nr_slabs);
1034 atomic_long_add(objects, &n->total_objects);
1037 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1039 struct kmem_cache_node *n = get_node(s, node);
1041 atomic_long_dec(&n->nr_slabs);
1042 atomic_long_sub(objects, &n->total_objects);
1045 /* Object debug checks for alloc/free paths */
1046 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1049 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1052 init_object(s, object, SLUB_RED_INACTIVE);
1053 init_tracking(s, object);
1056 static inline int alloc_consistency_checks(struct kmem_cache *s,
1058 void *object, unsigned long addr)
1060 if (!check_slab(s, page))
1063 if (!check_valid_pointer(s, page, object)) {
1064 object_err(s, page, object, "Freelist Pointer check fails");
1068 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1074 static noinline int alloc_debug_processing(struct kmem_cache *s,
1076 void *object, unsigned long addr)
1078 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1079 if (!alloc_consistency_checks(s, page, object, addr))
1083 /* Success perform special debug activities for allocs */
1084 if (s->flags & SLAB_STORE_USER)
1085 set_track(s, object, TRACK_ALLOC, addr);
1086 trace(s, page, object, 1);
1087 init_object(s, object, SLUB_RED_ACTIVE);
1091 if (PageSlab(page)) {
1093 * If this is a slab page then lets do the best we can
1094 * to avoid issues in the future. Marking all objects
1095 * as used avoids touching the remaining objects.
1097 slab_fix(s, "Marking all objects used");
1098 page->inuse = page->objects;
1099 page->freelist = NULL;
1104 static inline int free_consistency_checks(struct kmem_cache *s,
1105 struct page *page, void *object, unsigned long addr)
1107 if (!check_valid_pointer(s, page, object)) {
1108 slab_err(s, page, "Invalid object pointer 0x%p", object);
1112 if (on_freelist(s, page, object)) {
1113 object_err(s, page, object, "Object already free");
1117 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1120 if (unlikely(s != page->slab_cache)) {
1121 if (!PageSlab(page)) {
1122 slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1124 } else if (!page->slab_cache) {
1125 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1129 object_err(s, page, object,
1130 "page slab pointer corrupt.");
1136 /* Supports checking bulk free of a constructed freelist */
1137 static noinline int free_debug_processing(
1138 struct kmem_cache *s, struct page *page,
1139 void *head, void *tail, int bulk_cnt,
1142 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1143 void *object = head;
1145 unsigned long uninitialized_var(flags);
1148 spin_lock_irqsave(&n->list_lock, flags);
1151 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1152 if (!check_slab(s, page))
1159 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1160 if (!free_consistency_checks(s, page, object, addr))
1164 if (s->flags & SLAB_STORE_USER)
1165 set_track(s, object, TRACK_FREE, addr);
1166 trace(s, page, object, 0);
1167 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1168 init_object(s, object, SLUB_RED_INACTIVE);
1170 /* Reached end of constructed freelist yet? */
1171 if (object != tail) {
1172 object = get_freepointer(s, object);
1178 if (cnt != bulk_cnt)
1179 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1183 spin_unlock_irqrestore(&n->list_lock, flags);
1185 slab_fix(s, "Object at 0x%p not freed", object);
1189 static int __init setup_slub_debug(char *str)
1191 slub_debug = DEBUG_DEFAULT_FLAGS;
1192 if (*str++ != '=' || !*str)
1194 * No options specified. Switch on full debugging.
1200 * No options but restriction on slabs. This means full
1201 * debugging for slabs matching a pattern.
1208 * Switch off all debugging measures.
1213 * Determine which debug features should be switched on
1215 for (; *str && *str != ','; str++) {
1216 switch (tolower(*str)) {
1218 slub_debug |= SLAB_CONSISTENCY_CHECKS;
1221 slub_debug |= SLAB_RED_ZONE;
1224 slub_debug |= SLAB_POISON;
1227 slub_debug |= SLAB_STORE_USER;
1230 slub_debug |= SLAB_TRACE;
1233 slub_debug |= SLAB_FAILSLAB;
1237 * Avoid enabling debugging on caches if its minimum
1238 * order would increase as a result.
1240 disable_higher_order_debug = 1;
1243 pr_err("slub_debug option '%c' unknown. skipped\n",
1250 slub_debug_slabs = str + 1;
1255 __setup("slub_debug", setup_slub_debug);
1257 unsigned long kmem_cache_flags(unsigned long object_size,
1258 unsigned long flags, const char *name,
1259 void (*ctor)(void *))
1262 * Enable debugging if selected on the kernel commandline.
1264 if (slub_debug && (!slub_debug_slabs || (name &&
1265 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))))
1266 flags |= slub_debug;
1270 #else /* !CONFIG_SLUB_DEBUG */
1271 static inline void setup_object_debug(struct kmem_cache *s,
1272 struct page *page, void *object) {}
1274 static inline int alloc_debug_processing(struct kmem_cache *s,
1275 struct page *page, void *object, unsigned long addr) { return 0; }
1277 static inline int free_debug_processing(
1278 struct kmem_cache *s, struct page *page,
1279 void *head, void *tail, int bulk_cnt,
1280 unsigned long addr) { return 0; }
1282 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1284 static inline int check_object(struct kmem_cache *s, struct page *page,
1285 void *object, u8 val) { return 1; }
1286 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1287 struct page *page) {}
1288 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1289 struct page *page) {}
1290 unsigned long kmem_cache_flags(unsigned long object_size,
1291 unsigned long flags, const char *name,
1292 void (*ctor)(void *))
1296 #define slub_debug 0
1298 #define disable_higher_order_debug 0
1300 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1302 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1304 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1306 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1309 #endif /* CONFIG_SLUB_DEBUG */
1312 * Hooks for other subsystems that check memory allocations. In a typical
1313 * production configuration these hooks all should produce no code at all.
1315 static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1317 kmemleak_alloc(ptr, size, 1, flags);
1318 kasan_kmalloc_large(ptr, size, flags);
1321 static inline void kfree_hook(const void *x)
1324 kasan_kfree_large(x);
1327 static inline void *slab_free_hook(struct kmem_cache *s, void *x)
1331 kmemleak_free_recursive(x, s->flags);
1334 * Trouble is that we may no longer disable interrupts in the fast path
1335 * So in order to make the debug calls that expect irqs to be
1336 * disabled we need to disable interrupts temporarily.
1338 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1340 unsigned long flags;
1342 local_irq_save(flags);
1343 kmemcheck_slab_free(s, x, s->object_size);
1344 debug_check_no_locks_freed(x, s->object_size);
1345 local_irq_restore(flags);
1348 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1349 debug_check_no_obj_freed(x, s->object_size);
1351 freeptr = get_freepointer(s, x);
1353 * kasan_slab_free() may put x into memory quarantine, delaying its
1354 * reuse. In this case the object's freelist pointer is changed.
1356 kasan_slab_free(s, x);
1360 static inline void slab_free_freelist_hook(struct kmem_cache *s,
1361 void *head, void *tail)
1364 * Compiler cannot detect this function can be removed if slab_free_hook()
1365 * evaluates to nothing. Thus, catch all relevant config debug options here.
1367 #if defined(CONFIG_KMEMCHECK) || \
1368 defined(CONFIG_LOCKDEP) || \
1369 defined(CONFIG_DEBUG_KMEMLEAK) || \
1370 defined(CONFIG_DEBUG_OBJECTS_FREE) || \
1371 defined(CONFIG_KASAN)
1373 void *object = head;
1374 void *tail_obj = tail ? : head;
1378 freeptr = slab_free_hook(s, object);
1379 } while ((object != tail_obj) && (object = freeptr));
1383 static void setup_object(struct kmem_cache *s, struct page *page,
1386 setup_object_debug(s, page, object);
1387 if (unlikely(s->ctor)) {
1388 kasan_unpoison_object_data(s, object);
1390 kasan_poison_object_data(s, object);
1395 * Slab allocation and freeing
1397 static inline struct page *alloc_slab_page(struct kmem_cache *s,
1398 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1401 int order = oo_order(oo);
1403 flags |= __GFP_NOTRACK;
1405 if (node == NUMA_NO_NODE)
1406 page = alloc_pages(flags, order);
1408 page = __alloc_pages_node(node, flags, order);
1410 if (page && memcg_charge_slab(page, flags, order, s)) {
1411 __free_pages(page, order);
1418 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1419 /* Pre-initialize the random sequence cache */
1420 static int init_cache_random_seq(struct kmem_cache *s)
1423 unsigned long i, count = oo_objects(s->oo);
1425 err = cache_random_seq_create(s, count, GFP_KERNEL);
1427 pr_err("SLUB: Unable to initialize free list for %s\n",
1432 /* Transform to an offset on the set of pages */
1433 if (s->random_seq) {
1434 for (i = 0; i < count; i++)
1435 s->random_seq[i] *= s->size;
1440 /* Initialize each random sequence freelist per cache */
1441 static void __init init_freelist_randomization(void)
1443 struct kmem_cache *s;
1445 mutex_lock(&slab_mutex);
1447 list_for_each_entry(s, &slab_caches, list)
1448 init_cache_random_seq(s);
1450 mutex_unlock(&slab_mutex);
1453 /* Get the next entry on the pre-computed freelist randomized */
1454 static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1455 unsigned long *pos, void *start,
1456 unsigned long page_limit,
1457 unsigned long freelist_count)
1462 * If the target page allocation failed, the number of objects on the
1463 * page might be smaller than the usual size defined by the cache.
1466 idx = s->random_seq[*pos];
1468 if (*pos >= freelist_count)
1470 } while (unlikely(idx >= page_limit));
1472 return (char *)start + idx;
1475 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1476 static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1481 unsigned long idx, pos, page_limit, freelist_count;
1483 if (page->objects < 2 || !s->random_seq)
1486 freelist_count = oo_objects(s->oo);
1487 pos = get_random_int() % freelist_count;
1489 page_limit = page->objects * s->size;
1490 start = fixup_red_left(s, page_address(page));
1492 /* First entry is used as the base of the freelist */
1493 cur = next_freelist_entry(s, page, &pos, start, page_limit,
1495 page->freelist = cur;
1497 for (idx = 1; idx < page->objects; idx++) {
1498 setup_object(s, page, cur);
1499 next = next_freelist_entry(s, page, &pos, start, page_limit,
1501 set_freepointer(s, cur, next);
1504 setup_object(s, page, cur);
1505 set_freepointer(s, cur, NULL);
1510 static inline int init_cache_random_seq(struct kmem_cache *s)
1514 static inline void init_freelist_randomization(void) { }
1515 static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1519 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1521 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1524 struct kmem_cache_order_objects oo = s->oo;
1530 flags &= gfp_allowed_mask;
1532 if (gfpflags_allow_blocking(flags))
1535 flags |= s->allocflags;
1538 * Let the initial higher-order allocation fail under memory pressure
1539 * so we fall-back to the minimum order allocation.
1541 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1542 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1543 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1545 page = alloc_slab_page(s, alloc_gfp, node, oo);
1546 if (unlikely(!page)) {
1550 * Allocation may have failed due to fragmentation.
1551 * Try a lower order alloc if possible
1553 page = alloc_slab_page(s, alloc_gfp, node, oo);
1554 if (unlikely(!page))
1556 stat(s, ORDER_FALLBACK);
1559 if (kmemcheck_enabled &&
1560 !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1561 int pages = 1 << oo_order(oo);
1563 kmemcheck_alloc_shadow(page, oo_order(oo), alloc_gfp, node);
1566 * Objects from caches that have a constructor don't get
1567 * cleared when they're allocated, so we need to do it here.
1570 kmemcheck_mark_uninitialized_pages(page, pages);
1572 kmemcheck_mark_unallocated_pages(page, pages);
1575 page->objects = oo_objects(oo);
1577 order = compound_order(page);
1578 page->slab_cache = s;
1579 __SetPageSlab(page);
1580 if (page_is_pfmemalloc(page))
1581 SetPageSlabPfmemalloc(page);
1583 start = page_address(page);
1585 if (unlikely(s->flags & SLAB_POISON))
1586 memset(start, POISON_INUSE, PAGE_SIZE << order);
1588 kasan_poison_slab(page);
1590 shuffle = shuffle_freelist(s, page);
1593 for_each_object_idx(p, idx, s, start, page->objects) {
1594 setup_object(s, page, p);
1595 if (likely(idx < page->objects))
1596 set_freepointer(s, p, p + s->size);
1598 set_freepointer(s, p, NULL);
1600 page->freelist = fixup_red_left(s, start);
1603 page->inuse = page->objects;
1607 if (gfpflags_allow_blocking(flags))
1608 local_irq_disable();
1612 mod_zone_page_state(page_zone(page),
1613 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1614 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1617 inc_slabs_node(s, page_to_nid(page), page->objects);
1622 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1624 if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1625 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1626 flags &= ~GFP_SLAB_BUG_MASK;
1627 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1628 invalid_mask, &invalid_mask, flags, &flags);
1631 return allocate_slab(s,
1632 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1635 static void __free_slab(struct kmem_cache *s, struct page *page)
1637 int order = compound_order(page);
1638 int pages = 1 << order;
1640 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1643 slab_pad_check(s, page);
1644 for_each_object(p, s, page_address(page),
1646 check_object(s, page, p, SLUB_RED_INACTIVE);
1649 kmemcheck_free_shadow(page, compound_order(page));
1651 mod_zone_page_state(page_zone(page),
1652 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1653 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1656 __ClearPageSlabPfmemalloc(page);
1657 __ClearPageSlab(page);
1659 page_mapcount_reset(page);
1660 if (current->reclaim_state)
1661 current->reclaim_state->reclaimed_slab += pages;
1662 memcg_uncharge_slab(page, order, s);
1663 __free_pages(page, order);
1666 #define need_reserve_slab_rcu \
1667 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1669 static void rcu_free_slab(struct rcu_head *h)
1673 if (need_reserve_slab_rcu)
1674 page = virt_to_head_page(h);
1676 page = container_of((struct list_head *)h, struct page, lru);
1678 __free_slab(page->slab_cache, page);
1681 static void free_slab(struct kmem_cache *s, struct page *page)
1683 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1684 struct rcu_head *head;
1686 if (need_reserve_slab_rcu) {
1687 int order = compound_order(page);
1688 int offset = (PAGE_SIZE << order) - s->reserved;
1690 VM_BUG_ON(s->reserved != sizeof(*head));
1691 head = page_address(page) + offset;
1693 head = &page->rcu_head;
1696 call_rcu(head, rcu_free_slab);
1698 __free_slab(s, page);
1701 static void discard_slab(struct kmem_cache *s, struct page *page)
1703 dec_slabs_node(s, page_to_nid(page), page->objects);
1708 * Management of partially allocated slabs.
1711 __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1714 if (tail == DEACTIVATE_TO_TAIL)
1715 list_add_tail(&page->lru, &n->partial);
1717 list_add(&page->lru, &n->partial);
1720 static inline void add_partial(struct kmem_cache_node *n,
1721 struct page *page, int tail)
1723 lockdep_assert_held(&n->list_lock);
1724 __add_partial(n, page, tail);
1727 static inline void remove_partial(struct kmem_cache_node *n,
1730 lockdep_assert_held(&n->list_lock);
1731 list_del(&page->lru);
1736 * Remove slab from the partial list, freeze it and
1737 * return the pointer to the freelist.
1739 * Returns a list of objects or NULL if it fails.
1741 static inline void *acquire_slab(struct kmem_cache *s,
1742 struct kmem_cache_node *n, struct page *page,
1743 int mode, int *objects)
1746 unsigned long counters;
1749 lockdep_assert_held(&n->list_lock);
1752 * Zap the freelist and set the frozen bit.
1753 * The old freelist is the list of objects for the
1754 * per cpu allocation list.
1756 freelist = page->freelist;
1757 counters = page->counters;
1758 new.counters = counters;
1759 *objects = new.objects - new.inuse;
1761 new.inuse = page->objects;
1762 new.freelist = NULL;
1764 new.freelist = freelist;
1767 VM_BUG_ON(new.frozen);
1770 if (!__cmpxchg_double_slab(s, page,
1772 new.freelist, new.counters,
1776 remove_partial(n, page);
1781 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1782 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1785 * Try to allocate a partial slab from a specific node.
1787 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1788 struct kmem_cache_cpu *c, gfp_t flags)
1790 struct page *page, *page2;
1791 void *object = NULL;
1796 * Racy check. If we mistakenly see no partial slabs then we
1797 * just allocate an empty slab. If we mistakenly try to get a
1798 * partial slab and there is none available then get_partials()
1801 if (!n || !n->nr_partial)
1804 spin_lock(&n->list_lock);
1805 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1808 if (!pfmemalloc_match(page, flags))
1811 t = acquire_slab(s, n, page, object == NULL, &objects);
1815 available += objects;
1818 stat(s, ALLOC_FROM_PARTIAL);
1821 put_cpu_partial(s, page, 0);
1822 stat(s, CPU_PARTIAL_NODE);
1824 if (!kmem_cache_has_cpu_partial(s)
1825 || available > s->cpu_partial / 2)
1829 spin_unlock(&n->list_lock);
1834 * Get a page from somewhere. Search in increasing NUMA distances.
1836 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1837 struct kmem_cache_cpu *c)
1840 struct zonelist *zonelist;
1843 enum zone_type high_zoneidx = gfp_zone(flags);
1845 unsigned int cpuset_mems_cookie;
1848 * The defrag ratio allows a configuration of the tradeoffs between
1849 * inter node defragmentation and node local allocations. A lower
1850 * defrag_ratio increases the tendency to do local allocations
1851 * instead of attempting to obtain partial slabs from other nodes.
1853 * If the defrag_ratio is set to 0 then kmalloc() always
1854 * returns node local objects. If the ratio is higher then kmalloc()
1855 * may return off node objects because partial slabs are obtained
1856 * from other nodes and filled up.
1858 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
1859 * (which makes defrag_ratio = 1000) then every (well almost)
1860 * allocation will first attempt to defrag slab caches on other nodes.
1861 * This means scanning over all nodes to look for partial slabs which
1862 * may be expensive if we do it every time we are trying to find a slab
1863 * with available objects.
1865 if (!s->remote_node_defrag_ratio ||
1866 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1870 cpuset_mems_cookie = read_mems_allowed_begin();
1871 zonelist = node_zonelist(mempolicy_slab_node(), flags);
1872 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1873 struct kmem_cache_node *n;
1875 n = get_node(s, zone_to_nid(zone));
1877 if (n && cpuset_zone_allowed(zone, flags) &&
1878 n->nr_partial > s->min_partial) {
1879 object = get_partial_node(s, n, c, flags);
1882 * Don't check read_mems_allowed_retry()
1883 * here - if mems_allowed was updated in
1884 * parallel, that was a harmless race
1885 * between allocation and the cpuset
1892 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1898 * Get a partial page, lock it and return it.
1900 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1901 struct kmem_cache_cpu *c)
1904 int searchnode = node;
1906 if (node == NUMA_NO_NODE)
1907 searchnode = numa_mem_id();
1908 else if (!node_present_pages(node))
1909 searchnode = node_to_mem_node(node);
1911 object = get_partial_node(s, get_node(s, searchnode), c, flags);
1912 if (object || node != NUMA_NO_NODE)
1915 return get_any_partial(s, flags, c);
1918 #ifdef CONFIG_PREEMPT
1920 * Calculate the next globally unique transaction for disambiguiation
1921 * during cmpxchg. The transactions start with the cpu number and are then
1922 * incremented by CONFIG_NR_CPUS.
1924 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1927 * No preemption supported therefore also no need to check for
1933 static inline unsigned long next_tid(unsigned long tid)
1935 return tid + TID_STEP;
1938 static inline unsigned int tid_to_cpu(unsigned long tid)
1940 return tid % TID_STEP;
1943 static inline unsigned long tid_to_event(unsigned long tid)
1945 return tid / TID_STEP;
1948 static inline unsigned int init_tid(int cpu)
1953 static inline void note_cmpxchg_failure(const char *n,
1954 const struct kmem_cache *s, unsigned long tid)
1956 #ifdef SLUB_DEBUG_CMPXCHG
1957 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1959 pr_info("%s %s: cmpxchg redo ", n, s->name);
1961 #ifdef CONFIG_PREEMPT
1962 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1963 pr_warn("due to cpu change %d -> %d\n",
1964 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1967 if (tid_to_event(tid) != tid_to_event(actual_tid))
1968 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1969 tid_to_event(tid), tid_to_event(actual_tid));
1971 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1972 actual_tid, tid, next_tid(tid));
1974 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1977 static void init_kmem_cache_cpus(struct kmem_cache *s)
1981 for_each_possible_cpu(cpu)
1982 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1986 * Remove the cpu slab
1988 static void deactivate_slab(struct kmem_cache *s, struct page *page,
1991 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1992 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1994 enum slab_modes l = M_NONE, m = M_NONE;
1996 int tail = DEACTIVATE_TO_HEAD;
2000 if (page->freelist) {
2001 stat(s, DEACTIVATE_REMOTE_FREES);
2002 tail = DEACTIVATE_TO_TAIL;
2006 * Stage one: Free all available per cpu objects back
2007 * to the page freelist while it is still frozen. Leave the
2010 * There is no need to take the list->lock because the page
2013 while (freelist && (nextfree = get_freepointer(s, freelist))) {
2015 unsigned long counters;
2018 prior = page->freelist;
2019 counters = page->counters;
2020 set_freepointer(s, freelist, prior);
2021 new.counters = counters;
2023 VM_BUG_ON(!new.frozen);
2025 } while (!__cmpxchg_double_slab(s, page,
2027 freelist, new.counters,
2028 "drain percpu freelist"));
2030 freelist = nextfree;
2034 * Stage two: Ensure that the page is unfrozen while the
2035 * list presence reflects the actual number of objects
2038 * We setup the list membership and then perform a cmpxchg
2039 * with the count. If there is a mismatch then the page
2040 * is not unfrozen but the page is on the wrong list.
2042 * Then we restart the process which may have to remove
2043 * the page from the list that we just put it on again
2044 * because the number of objects in the slab may have
2049 old.freelist = page->freelist;
2050 old.counters = page->counters;
2051 VM_BUG_ON(!old.frozen);
2053 /* Determine target state of the slab */
2054 new.counters = old.counters;
2057 set_freepointer(s, freelist, old.freelist);
2058 new.freelist = freelist;
2060 new.freelist = old.freelist;
2064 if (!new.inuse && n->nr_partial >= s->min_partial)
2066 else if (new.freelist) {
2071 * Taking the spinlock removes the possiblity
2072 * that acquire_slab() will see a slab page that
2075 spin_lock(&n->list_lock);
2079 if (kmem_cache_debug(s) && !lock) {
2082 * This also ensures that the scanning of full
2083 * slabs from diagnostic functions will not see
2086 spin_lock(&n->list_lock);
2094 remove_partial(n, page);
2096 else if (l == M_FULL)
2098 remove_full(s, n, page);
2100 if (m == M_PARTIAL) {
2102 add_partial(n, page, tail);
2105 } else if (m == M_FULL) {
2107 stat(s, DEACTIVATE_FULL);
2108 add_full(s, n, page);
2114 if (!__cmpxchg_double_slab(s, page,
2115 old.freelist, old.counters,
2116 new.freelist, new.counters,
2121 spin_unlock(&n->list_lock);
2124 stat(s, DEACTIVATE_EMPTY);
2125 discard_slab(s, page);
2131 * Unfreeze all the cpu partial slabs.
2133 * This function must be called with interrupts disabled
2134 * for the cpu using c (or some other guarantee must be there
2135 * to guarantee no concurrent accesses).
2137 static void unfreeze_partials(struct kmem_cache *s,
2138 struct kmem_cache_cpu *c)
2140 #ifdef CONFIG_SLUB_CPU_PARTIAL
2141 struct kmem_cache_node *n = NULL, *n2 = NULL;
2142 struct page *page, *discard_page = NULL;
2144 while ((page = c->partial)) {
2148 c->partial = page->next;
2150 n2 = get_node(s, page_to_nid(page));
2153 spin_unlock(&n->list_lock);
2156 spin_lock(&n->list_lock);
2161 old.freelist = page->freelist;
2162 old.counters = page->counters;
2163 VM_BUG_ON(!old.frozen);
2165 new.counters = old.counters;
2166 new.freelist = old.freelist;
2170 } while (!__cmpxchg_double_slab(s, page,
2171 old.freelist, old.counters,
2172 new.freelist, new.counters,
2173 "unfreezing slab"));
2175 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2176 page->next = discard_page;
2177 discard_page = page;
2179 add_partial(n, page, DEACTIVATE_TO_TAIL);
2180 stat(s, FREE_ADD_PARTIAL);
2185 spin_unlock(&n->list_lock);
2187 while (discard_page) {
2188 page = discard_page;
2189 discard_page = discard_page->next;
2191 stat(s, DEACTIVATE_EMPTY);
2192 discard_slab(s, page);
2199 * Put a page that was just frozen (in __slab_free) into a partial page
2200 * slot if available. This is done without interrupts disabled and without
2201 * preemption disabled. The cmpxchg is racy and may put the partial page
2202 * onto a random cpus partial slot.
2204 * If we did not find a slot then simply move all the partials to the
2205 * per node partial list.
2207 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2209 #ifdef CONFIG_SLUB_CPU_PARTIAL
2210 struct page *oldpage;
2218 oldpage = this_cpu_read(s->cpu_slab->partial);
2221 pobjects = oldpage->pobjects;
2222 pages = oldpage->pages;
2223 if (drain && pobjects > s->cpu_partial) {
2224 unsigned long flags;
2226 * partial array is full. Move the existing
2227 * set to the per node partial list.
2229 local_irq_save(flags);
2230 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2231 local_irq_restore(flags);
2235 stat(s, CPU_PARTIAL_DRAIN);
2240 pobjects += page->objects - page->inuse;
2242 page->pages = pages;
2243 page->pobjects = pobjects;
2244 page->next = oldpage;
2246 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2248 if (unlikely(!s->cpu_partial)) {
2249 unsigned long flags;
2251 local_irq_save(flags);
2252 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2253 local_irq_restore(flags);
2259 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2261 stat(s, CPUSLAB_FLUSH);
2262 deactivate_slab(s, c->page, c->freelist);
2264 c->tid = next_tid(c->tid);
2272 * Called from IPI handler with interrupts disabled.
2274 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2276 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2282 unfreeze_partials(s, c);
2286 static void flush_cpu_slab(void *d)
2288 struct kmem_cache *s = d;
2290 __flush_cpu_slab(s, smp_processor_id());
2293 static bool has_cpu_slab(int cpu, void *info)
2295 struct kmem_cache *s = info;
2296 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2298 return c->page || c->partial;
2301 static void flush_all(struct kmem_cache *s)
2303 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2307 * Check if the objects in a per cpu structure fit numa
2308 * locality expectations.
2310 static inline int node_match(struct page *page, int node)
2313 if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2319 #ifdef CONFIG_SLUB_DEBUG
2320 static int count_free(struct page *page)
2322 return page->objects - page->inuse;
2325 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2327 return atomic_long_read(&n->total_objects);
2329 #endif /* CONFIG_SLUB_DEBUG */
2331 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2332 static unsigned long count_partial(struct kmem_cache_node *n,
2333 int (*get_count)(struct page *))
2335 unsigned long flags;
2336 unsigned long x = 0;
2339 spin_lock_irqsave(&n->list_lock, flags);
2340 list_for_each_entry(page, &n->partial, lru)
2341 x += get_count(page);
2342 spin_unlock_irqrestore(&n->list_lock, flags);
2345 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2347 static noinline void
2348 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2350 #ifdef CONFIG_SLUB_DEBUG
2351 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2352 DEFAULT_RATELIMIT_BURST);
2354 struct kmem_cache_node *n;
2356 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2359 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2360 nid, gfpflags, &gfpflags);
2361 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2362 s->name, s->object_size, s->size, oo_order(s->oo),
2365 if (oo_order(s->min) > get_order(s->object_size))
2366 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2369 for_each_kmem_cache_node(s, node, n) {
2370 unsigned long nr_slabs;
2371 unsigned long nr_objs;
2372 unsigned long nr_free;
2374 nr_free = count_partial(n, count_free);
2375 nr_slabs = node_nr_slabs(n);
2376 nr_objs = node_nr_objs(n);
2378 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2379 node, nr_slabs, nr_objs, nr_free);
2384 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2385 int node, struct kmem_cache_cpu **pc)
2388 struct kmem_cache_cpu *c = *pc;
2391 freelist = get_partial(s, flags, node, c);
2396 page = new_slab(s, flags, node);
2398 c = raw_cpu_ptr(s->cpu_slab);
2403 * No other reference to the page yet so we can
2404 * muck around with it freely without cmpxchg
2406 freelist = page->freelist;
2407 page->freelist = NULL;
2409 stat(s, ALLOC_SLAB);
2418 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2420 if (unlikely(PageSlabPfmemalloc(page)))
2421 return gfp_pfmemalloc_allowed(gfpflags);
2427 * Check the page->freelist of a page and either transfer the freelist to the
2428 * per cpu freelist or deactivate the page.
2430 * The page is still frozen if the return value is not NULL.
2432 * If this function returns NULL then the page has been unfrozen.
2434 * This function must be called with interrupt disabled.
2436 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2439 unsigned long counters;
2443 freelist = page->freelist;
2444 counters = page->counters;
2446 new.counters = counters;
2447 VM_BUG_ON(!new.frozen);
2449 new.inuse = page->objects;
2450 new.frozen = freelist != NULL;
2452 } while (!__cmpxchg_double_slab(s, page,
2461 * Slow path. The lockless freelist is empty or we need to perform
2464 * Processing is still very fast if new objects have been freed to the
2465 * regular freelist. In that case we simply take over the regular freelist
2466 * as the lockless freelist and zap the regular freelist.
2468 * If that is not working then we fall back to the partial lists. We take the
2469 * first element of the freelist as the object to allocate now and move the
2470 * rest of the freelist to the lockless freelist.
2472 * And if we were unable to get a new slab from the partial slab lists then
2473 * we need to allocate a new slab. This is the slowest path since it involves
2474 * a call to the page allocator and the setup of a new slab.
2476 * Version of __slab_alloc to use when we know that interrupts are
2477 * already disabled (which is the case for bulk allocation).
2479 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2480 unsigned long addr, struct kmem_cache_cpu *c)
2490 if (unlikely(!node_match(page, node))) {
2491 int searchnode = node;
2493 if (node != NUMA_NO_NODE && !node_present_pages(node))
2494 searchnode = node_to_mem_node(node);
2496 if (unlikely(!node_match(page, searchnode))) {
2497 stat(s, ALLOC_NODE_MISMATCH);
2498 deactivate_slab(s, page, c->freelist);
2506 * By rights, we should be searching for a slab page that was
2507 * PFMEMALLOC but right now, we are losing the pfmemalloc
2508 * information when the page leaves the per-cpu allocator
2510 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2511 deactivate_slab(s, page, c->freelist);
2517 /* must check again c->freelist in case of cpu migration or IRQ */
2518 freelist = c->freelist;
2522 freelist = get_freelist(s, page);
2526 stat(s, DEACTIVATE_BYPASS);
2530 stat(s, ALLOC_REFILL);
2534 * freelist is pointing to the list of objects to be used.
2535 * page is pointing to the page from which the objects are obtained.
2536 * That page must be frozen for per cpu allocations to work.
2538 VM_BUG_ON(!c->page->frozen);
2539 c->freelist = get_freepointer(s, freelist);
2540 c->tid = next_tid(c->tid);
2546 page = c->page = c->partial;
2547 c->partial = page->next;
2548 stat(s, CPU_PARTIAL_ALLOC);
2553 freelist = new_slab_objects(s, gfpflags, node, &c);
2555 if (unlikely(!freelist)) {
2556 slab_out_of_memory(s, gfpflags, node);
2561 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2564 /* Only entered in the debug case */
2565 if (kmem_cache_debug(s) &&
2566 !alloc_debug_processing(s, page, freelist, addr))
2567 goto new_slab; /* Slab failed checks. Next slab needed */
2569 deactivate_slab(s, page, get_freepointer(s, freelist));
2576 * Another one that disabled interrupt and compensates for possible
2577 * cpu changes by refetching the per cpu area pointer.
2579 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2580 unsigned long addr, struct kmem_cache_cpu *c)
2583 unsigned long flags;
2585 local_irq_save(flags);
2586 #ifdef CONFIG_PREEMPT
2588 * We may have been preempted and rescheduled on a different
2589 * cpu before disabling interrupts. Need to reload cpu area
2592 c = this_cpu_ptr(s->cpu_slab);
2595 p = ___slab_alloc(s, gfpflags, node, addr, c);
2596 local_irq_restore(flags);
2601 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2602 * have the fastpath folded into their functions. So no function call
2603 * overhead for requests that can be satisfied on the fastpath.
2605 * The fastpath works by first checking if the lockless freelist can be used.
2606 * If not then __slab_alloc is called for slow processing.
2608 * Otherwise we can simply pick the next object from the lockless free list.
2610 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2611 gfp_t gfpflags, int node, unsigned long addr)
2614 struct kmem_cache_cpu *c;
2618 s = slab_pre_alloc_hook(s, gfpflags);
2623 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2624 * enabled. We may switch back and forth between cpus while
2625 * reading from one cpu area. That does not matter as long
2626 * as we end up on the original cpu again when doing the cmpxchg.
2628 * We should guarantee that tid and kmem_cache are retrieved on
2629 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2630 * to check if it is matched or not.
2633 tid = this_cpu_read(s->cpu_slab->tid);
2634 c = raw_cpu_ptr(s->cpu_slab);
2635 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2636 unlikely(tid != READ_ONCE(c->tid)));
2639 * Irqless object alloc/free algorithm used here depends on sequence
2640 * of fetching cpu_slab's data. tid should be fetched before anything
2641 * on c to guarantee that object and page associated with previous tid
2642 * won't be used with current tid. If we fetch tid first, object and
2643 * page could be one associated with next tid and our alloc/free
2644 * request will be failed. In this case, we will retry. So, no problem.
2649 * The transaction ids are globally unique per cpu and per operation on
2650 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2651 * occurs on the right processor and that there was no operation on the
2652 * linked list in between.
2655 object = c->freelist;
2657 if (unlikely(!object || !node_match(page, node))) {
2658 object = __slab_alloc(s, gfpflags, node, addr, c);
2659 stat(s, ALLOC_SLOWPATH);
2661 void *next_object = get_freepointer_safe(s, object);
2664 * The cmpxchg will only match if there was no additional
2665 * operation and if we are on the right processor.
2667 * The cmpxchg does the following atomically (without lock
2669 * 1. Relocate first pointer to the current per cpu area.
2670 * 2. Verify that tid and freelist have not been changed
2671 * 3. If they were not changed replace tid and freelist
2673 * Since this is without lock semantics the protection is only
2674 * against code executing on this cpu *not* from access by
2677 if (unlikely(!this_cpu_cmpxchg_double(
2678 s->cpu_slab->freelist, s->cpu_slab->tid,
2680 next_object, next_tid(tid)))) {
2682 note_cmpxchg_failure("slab_alloc", s, tid);
2685 prefetch_freepointer(s, next_object);
2686 stat(s, ALLOC_FASTPATH);
2689 if (unlikely(gfpflags & __GFP_ZERO) && object)
2690 memset(object, 0, s->object_size);
2692 slab_post_alloc_hook(s, gfpflags, 1, &object);
2697 static __always_inline void *slab_alloc(struct kmem_cache *s,
2698 gfp_t gfpflags, unsigned long addr)
2700 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2703 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2705 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2707 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2712 EXPORT_SYMBOL(kmem_cache_alloc);
2714 #ifdef CONFIG_TRACING
2715 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2717 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2718 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2719 kasan_kmalloc(s, ret, size, gfpflags);
2722 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2726 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2728 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2730 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2731 s->object_size, s->size, gfpflags, node);
2735 EXPORT_SYMBOL(kmem_cache_alloc_node);
2737 #ifdef CONFIG_TRACING
2738 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2740 int node, size_t size)
2742 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2744 trace_kmalloc_node(_RET_IP_, ret,
2745 size, s->size, gfpflags, node);
2747 kasan_kmalloc(s, ret, size, gfpflags);
2750 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2755 * Slow path handling. This may still be called frequently since objects
2756 * have a longer lifetime than the cpu slabs in most processing loads.
2758 * So we still attempt to reduce cache line usage. Just take the slab
2759 * lock and free the item. If there is no additional partial page
2760 * handling required then we can return immediately.
2762 static void __slab_free(struct kmem_cache *s, struct page *page,
2763 void *head, void *tail, int cnt,
2770 unsigned long counters;
2771 struct kmem_cache_node *n = NULL;
2772 unsigned long uninitialized_var(flags);
2774 stat(s, FREE_SLOWPATH);
2776 if (kmem_cache_debug(s) &&
2777 !free_debug_processing(s, page, head, tail, cnt, addr))
2782 spin_unlock_irqrestore(&n->list_lock, flags);
2785 prior = page->freelist;
2786 counters = page->counters;
2787 set_freepointer(s, tail, prior);
2788 new.counters = counters;
2789 was_frozen = new.frozen;
2791 if ((!new.inuse || !prior) && !was_frozen) {
2793 if (kmem_cache_has_cpu_partial(s) && !prior) {
2796 * Slab was on no list before and will be
2798 * We can defer the list move and instead
2803 } else { /* Needs to be taken off a list */
2805 n = get_node(s, page_to_nid(page));
2807 * Speculatively acquire the list_lock.
2808 * If the cmpxchg does not succeed then we may
2809 * drop the list_lock without any processing.
2811 * Otherwise the list_lock will synchronize with
2812 * other processors updating the list of slabs.
2814 spin_lock_irqsave(&n->list_lock, flags);
2819 } while (!cmpxchg_double_slab(s, page,
2827 * If we just froze the page then put it onto the
2828 * per cpu partial list.
2830 if (new.frozen && !was_frozen) {
2831 put_cpu_partial(s, page, 1);
2832 stat(s, CPU_PARTIAL_FREE);
2835 * The list lock was not taken therefore no list
2836 * activity can be necessary.
2839 stat(s, FREE_FROZEN);
2843 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2847 * Objects left in the slab. If it was not on the partial list before
2850 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2851 if (kmem_cache_debug(s))
2852 remove_full(s, n, page);
2853 add_partial(n, page, DEACTIVATE_TO_TAIL);
2854 stat(s, FREE_ADD_PARTIAL);
2856 spin_unlock_irqrestore(&n->list_lock, flags);
2862 * Slab on the partial list.
2864 remove_partial(n, page);
2865 stat(s, FREE_REMOVE_PARTIAL);
2867 /* Slab must be on the full list */
2868 remove_full(s, n, page);
2871 spin_unlock_irqrestore(&n->list_lock, flags);
2873 discard_slab(s, page);
2877 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2878 * can perform fastpath freeing without additional function calls.
2880 * The fastpath is only possible if we are freeing to the current cpu slab
2881 * of this processor. This typically the case if we have just allocated
2884 * If fastpath is not possible then fall back to __slab_free where we deal
2885 * with all sorts of special processing.
2887 * Bulk free of a freelist with several objects (all pointing to the
2888 * same page) possible by specifying head and tail ptr, plus objects
2889 * count (cnt). Bulk free indicated by tail pointer being set.
2891 static __always_inline void do_slab_free(struct kmem_cache *s,
2892 struct page *page, void *head, void *tail,
2893 int cnt, unsigned long addr)
2895 void *tail_obj = tail ? : head;
2896 struct kmem_cache_cpu *c;
2900 * Determine the currently cpus per cpu slab.
2901 * The cpu may change afterward. However that does not matter since
2902 * data is retrieved via this pointer. If we are on the same cpu
2903 * during the cmpxchg then the free will succeed.
2906 tid = this_cpu_read(s->cpu_slab->tid);
2907 c = raw_cpu_ptr(s->cpu_slab);
2908 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2909 unlikely(tid != READ_ONCE(c->tid)));
2911 /* Same with comment on barrier() in slab_alloc_node() */
2914 if (likely(page == c->page)) {
2915 set_freepointer(s, tail_obj, c->freelist);
2917 if (unlikely(!this_cpu_cmpxchg_double(
2918 s->cpu_slab->freelist, s->cpu_slab->tid,
2920 head, next_tid(tid)))) {
2922 note_cmpxchg_failure("slab_free", s, tid);
2925 stat(s, FREE_FASTPATH);
2927 __slab_free(s, page, head, tail_obj, cnt, addr);
2931 static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2932 void *head, void *tail, int cnt,
2935 slab_free_freelist_hook(s, head, tail);
2937 * slab_free_freelist_hook() could have put the items into quarantine.
2938 * If so, no need to free them.
2940 if (s->flags & SLAB_KASAN && !(s->flags & SLAB_DESTROY_BY_RCU))
2942 do_slab_free(s, page, head, tail, cnt, addr);
2946 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
2948 do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
2952 void kmem_cache_free(struct kmem_cache *s, void *x)
2954 s = cache_from_obj(s, x);
2957 slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
2958 trace_kmem_cache_free(_RET_IP_, x);
2960 EXPORT_SYMBOL(kmem_cache_free);
2962 struct detached_freelist {
2967 struct kmem_cache *s;
2971 * This function progressively scans the array with free objects (with
2972 * a limited look ahead) and extract objects belonging to the same
2973 * page. It builds a detached freelist directly within the given
2974 * page/objects. This can happen without any need for
2975 * synchronization, because the objects are owned by running process.
2976 * The freelist is build up as a single linked list in the objects.
2977 * The idea is, that this detached freelist can then be bulk
2978 * transferred to the real freelist(s), but only requiring a single
2979 * synchronization primitive. Look ahead in the array is limited due
2980 * to performance reasons.
2983 int build_detached_freelist(struct kmem_cache *s, size_t size,
2984 void **p, struct detached_freelist *df)
2986 size_t first_skipped_index = 0;
2991 /* Always re-init detached_freelist */
2996 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
2997 } while (!object && size);
3002 page = virt_to_head_page(object);
3004 /* Handle kalloc'ed objects */
3005 if (unlikely(!PageSlab(page))) {
3006 BUG_ON(!PageCompound(page));
3008 __free_pages(page, compound_order(page));
3009 p[size] = NULL; /* mark object processed */
3012 /* Derive kmem_cache from object */
3013 df->s = page->slab_cache;
3015 df->s = cache_from_obj(s, object); /* Support for memcg */
3018 /* Start new detached freelist */
3020 set_freepointer(df->s, object, NULL);
3022 df->freelist = object;
3023 p[size] = NULL; /* mark object processed */
3029 continue; /* Skip processed objects */
3031 /* df->page is always set at this point */
3032 if (df->page == virt_to_head_page(object)) {
3033 /* Opportunity build freelist */
3034 set_freepointer(df->s, object, df->freelist);
3035 df->freelist = object;
3037 p[size] = NULL; /* mark object processed */
3042 /* Limit look ahead search */
3046 if (!first_skipped_index)
3047 first_skipped_index = size + 1;
3050 return first_skipped_index;
3053 /* Note that interrupts must be enabled when calling this function. */
3054 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3060 struct detached_freelist df;
3062 size = build_detached_freelist(s, size, p, &df);
3063 if (unlikely(!df.page))
3066 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3067 } while (likely(size));
3069 EXPORT_SYMBOL(kmem_cache_free_bulk);
3071 /* Note that interrupts must be enabled when calling this function. */
3072 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3075 struct kmem_cache_cpu *c;
3078 /* memcg and kmem_cache debug support */
3079 s = slab_pre_alloc_hook(s, flags);
3083 * Drain objects in the per cpu slab, while disabling local
3084 * IRQs, which protects against PREEMPT and interrupts
3085 * handlers invoking normal fastpath.
3087 local_irq_disable();
3088 c = this_cpu_ptr(s->cpu_slab);
3090 for (i = 0; i < size; i++) {
3091 void *object = c->freelist;
3093 if (unlikely(!object)) {
3095 * Invoking slow path likely have side-effect
3096 * of re-populating per CPU c->freelist
3098 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3100 if (unlikely(!p[i]))
3103 c = this_cpu_ptr(s->cpu_slab);
3104 continue; /* goto for-loop */
3106 c->freelist = get_freepointer(s, object);
3109 c->tid = next_tid(c->tid);
3112 /* Clear memory outside IRQ disabled fastpath loop */
3113 if (unlikely(flags & __GFP_ZERO)) {
3116 for (j = 0; j < i; j++)
3117 memset(p[j], 0, s->object_size);
3120 /* memcg and kmem_cache debug support */
3121 slab_post_alloc_hook(s, flags, size, p);
3125 slab_post_alloc_hook(s, flags, i, p);
3126 __kmem_cache_free_bulk(s, i, p);
3129 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3133 * Object placement in a slab is made very easy because we always start at
3134 * offset 0. If we tune the size of the object to the alignment then we can
3135 * get the required alignment by putting one properly sized object after
3138 * Notice that the allocation order determines the sizes of the per cpu
3139 * caches. Each processor has always one slab available for allocations.
3140 * Increasing the allocation order reduces the number of times that slabs
3141 * must be moved on and off the partial lists and is therefore a factor in
3146 * Mininum / Maximum order of slab pages. This influences locking overhead
3147 * and slab fragmentation. A higher order reduces the number of partial slabs
3148 * and increases the number of allocations possible without having to
3149 * take the list_lock.
3151 static int slub_min_order;
3152 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3153 static int slub_min_objects;
3156 * Calculate the order of allocation given an slab object size.
3158 * The order of allocation has significant impact on performance and other
3159 * system components. Generally order 0 allocations should be preferred since
3160 * order 0 does not cause fragmentation in the page allocator. Larger objects
3161 * be problematic to put into order 0 slabs because there may be too much
3162 * unused space left. We go to a higher order if more than 1/16th of the slab
3165 * In order to reach satisfactory performance we must ensure that a minimum
3166 * number of objects is in one slab. Otherwise we may generate too much
3167 * activity on the partial lists which requires taking the list_lock. This is
3168 * less a concern for large slabs though which are rarely used.
3170 * slub_max_order specifies the order where we begin to stop considering the
3171 * number of objects in a slab as critical. If we reach slub_max_order then
3172 * we try to keep the page order as low as possible. So we accept more waste
3173 * of space in favor of a small page order.
3175 * Higher order allocations also allow the placement of more objects in a
3176 * slab and thereby reduce object handling overhead. If the user has
3177 * requested a higher mininum order then we start with that one instead of
3178 * the smallest order which will fit the object.
3180 static inline int slab_order(int size, int min_objects,
3181 int max_order, int fract_leftover, int reserved)
3185 int min_order = slub_min_order;
3187 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
3188 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3190 for (order = max(min_order, get_order(min_objects * size + reserved));
3191 order <= max_order; order++) {
3193 unsigned long slab_size = PAGE_SIZE << order;
3195 rem = (slab_size - reserved) % size;
3197 if (rem <= slab_size / fract_leftover)
3204 static inline int calculate_order(int size, int reserved)
3212 * Attempt to find best configuration for a slab. This
3213 * works by first attempting to generate a layout with
3214 * the best configuration and backing off gradually.
3216 * First we increase the acceptable waste in a slab. Then
3217 * we reduce the minimum objects required in a slab.
3219 min_objects = slub_min_objects;
3221 min_objects = 4 * (fls(nr_cpu_ids) + 1);
3222 max_objects = order_objects(slub_max_order, size, reserved);
3223 min_objects = min(min_objects, max_objects);
3225 while (min_objects > 1) {
3227 while (fraction >= 4) {
3228 order = slab_order(size, min_objects,
3229 slub_max_order, fraction, reserved);
3230 if (order <= slub_max_order)
3238 * We were unable to place multiple objects in a slab. Now
3239 * lets see if we can place a single object there.
3241 order = slab_order(size, 1, slub_max_order, 1, reserved);
3242 if (order <= slub_max_order)
3246 * Doh this slab cannot be placed using slub_max_order.
3248 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
3249 if (order < MAX_ORDER)
3255 init_kmem_cache_node(struct kmem_cache_node *n)
3258 spin_lock_init(&n->list_lock);
3259 INIT_LIST_HEAD(&n->partial);
3260 #ifdef CONFIG_SLUB_DEBUG
3261 atomic_long_set(&n->nr_slabs, 0);
3262 atomic_long_set(&n->total_objects, 0);
3263 INIT_LIST_HEAD(&n->full);
3267 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3269 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3270 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3273 * Must align to double word boundary for the double cmpxchg
3274 * instructions to work; see __pcpu_double_call_return_bool().
3276 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3277 2 * sizeof(void *));
3282 init_kmem_cache_cpus(s);
3287 static struct kmem_cache *kmem_cache_node;
3290 * No kmalloc_node yet so do it by hand. We know that this is the first
3291 * slab on the node for this slabcache. There are no concurrent accesses
3294 * Note that this function only works on the kmem_cache_node
3295 * when allocating for the kmem_cache_node. This is used for bootstrapping
3296 * memory on a fresh node that has no slab structures yet.
3298 static void early_kmem_cache_node_alloc(int node)
3301 struct kmem_cache_node *n;
3303 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3305 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3308 if (page_to_nid(page) != node) {
3309 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3310 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3315 page->freelist = get_freepointer(kmem_cache_node, n);
3318 kmem_cache_node->node[node] = n;
3319 #ifdef CONFIG_SLUB_DEBUG
3320 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3321 init_tracking(kmem_cache_node, n);
3323 kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3325 init_kmem_cache_node(n);
3326 inc_slabs_node(kmem_cache_node, node, page->objects);
3329 * No locks need to be taken here as it has just been
3330 * initialized and there is no concurrent access.
3332 __add_partial(n, page, DEACTIVATE_TO_HEAD);
3335 static void free_kmem_cache_nodes(struct kmem_cache *s)
3338 struct kmem_cache_node *n;
3340 for_each_kmem_cache_node(s, node, n) {
3341 kmem_cache_free(kmem_cache_node, n);
3342 s->node[node] = NULL;
3346 void __kmem_cache_release(struct kmem_cache *s)
3348 cache_random_seq_destroy(s);
3349 free_percpu(s->cpu_slab);
3350 free_kmem_cache_nodes(s);
3353 static int init_kmem_cache_nodes(struct kmem_cache *s)
3357 for_each_node_state(node, N_NORMAL_MEMORY) {
3358 struct kmem_cache_node *n;
3360 if (slab_state == DOWN) {
3361 early_kmem_cache_node_alloc(node);
3364 n = kmem_cache_alloc_node(kmem_cache_node,
3368 free_kmem_cache_nodes(s);
3373 init_kmem_cache_node(n);
3378 static void set_min_partial(struct kmem_cache *s, unsigned long min)
3380 if (min < MIN_PARTIAL)
3382 else if (min > MAX_PARTIAL)
3384 s->min_partial = min;
3388 * calculate_sizes() determines the order and the distribution of data within
3391 static int calculate_sizes(struct kmem_cache *s, int forced_order)
3393 unsigned long flags = s->flags;
3394 size_t size = s->object_size;
3398 * Round up object size to the next word boundary. We can only
3399 * place the free pointer at word boundaries and this determines
3400 * the possible location of the free pointer.
3402 size = ALIGN(size, sizeof(void *));
3404 #ifdef CONFIG_SLUB_DEBUG
3406 * Determine if we can poison the object itself. If the user of
3407 * the slab may touch the object after free or before allocation
3408 * then we should never poison the object itself.
3410 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
3412 s->flags |= __OBJECT_POISON;
3414 s->flags &= ~__OBJECT_POISON;
3418 * If we are Redzoning then check if there is some space between the
3419 * end of the object and the free pointer. If not then add an
3420 * additional word to have some bytes to store Redzone information.
3422 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3423 size += sizeof(void *);
3427 * With that we have determined the number of bytes in actual use
3428 * by the object. This is the potential offset to the free pointer.
3432 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
3435 * Relocate free pointer after the object if it is not
3436 * permitted to overwrite the first word of the object on
3439 * This is the case if we do RCU, have a constructor or
3440 * destructor or are poisoning the objects.
3443 size += sizeof(void *);
3446 #ifdef CONFIG_SLUB_DEBUG
3447 if (flags & SLAB_STORE_USER)
3449 * Need to store information about allocs and frees after
3452 size += 2 * sizeof(struct track);
3455 kasan_cache_create(s, &size, &s->flags);
3456 #ifdef CONFIG_SLUB_DEBUG
3457 if (flags & SLAB_RED_ZONE) {
3459 * Add some empty padding so that we can catch
3460 * overwrites from earlier objects rather than let
3461 * tracking information or the free pointer be
3462 * corrupted if a user writes before the start
3465 size += sizeof(void *);
3467 s->red_left_pad = sizeof(void *);
3468 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3469 size += s->red_left_pad;
3474 * SLUB stores one object immediately after another beginning from
3475 * offset 0. In order to align the objects we have to simply size
3476 * each object to conform to the alignment.
3478 size = ALIGN(size, s->align);
3480 if (forced_order >= 0)
3481 order = forced_order;
3483 order = calculate_order(size, s->reserved);
3490 s->allocflags |= __GFP_COMP;
3492 if (s->flags & SLAB_CACHE_DMA)
3493 s->allocflags |= GFP_DMA;
3495 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3496 s->allocflags |= __GFP_RECLAIMABLE;
3499 * Determine the number of objects per slab
3501 s->oo = oo_make(order, size, s->reserved);
3502 s->min = oo_make(get_order(size), size, s->reserved);
3503 if (oo_objects(s->oo) > oo_objects(s->max))
3506 return !!oo_objects(s->oo);
3509 static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3511 s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3514 if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3515 s->reserved = sizeof(struct rcu_head);
3517 if (!calculate_sizes(s, -1))
3519 if (disable_higher_order_debug) {
3521 * Disable debugging flags that store metadata if the min slab
3524 if (get_order(s->size) > get_order(s->object_size)) {
3525 s->flags &= ~DEBUG_METADATA_FLAGS;
3527 if (!calculate_sizes(s, -1))
3532 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3533 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3534 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3535 /* Enable fast mode */
3536 s->flags |= __CMPXCHG_DOUBLE;
3540 * The larger the object size is, the more pages we want on the partial
3541 * list to avoid pounding the page allocator excessively.
3543 set_min_partial(s, ilog2(s->size) / 2);
3546 * cpu_partial determined the maximum number of objects kept in the
3547 * per cpu partial lists of a processor.
3549 * Per cpu partial lists mainly contain slabs that just have one
3550 * object freed. If they are used for allocation then they can be
3551 * filled up again with minimal effort. The slab will never hit the
3552 * per node partial lists and therefore no locking will be required.
3554 * This setting also determines
3556 * A) The number of objects from per cpu partial slabs dumped to the
3557 * per node list when we reach the limit.
3558 * B) The number of objects in cpu partial slabs to extract from the
3559 * per node list when we run out of per cpu objects. We only fetch
3560 * 50% to keep some capacity around for frees.
3562 if (!kmem_cache_has_cpu_partial(s))
3564 else if (s->size >= PAGE_SIZE)
3566 else if (s->size >= 1024)
3568 else if (s->size >= 256)
3569 s->cpu_partial = 13;
3571 s->cpu_partial = 30;
3574 s->remote_node_defrag_ratio = 1000;
3577 /* Initialize the pre-computed randomized freelist if slab is up */
3578 if (slab_state >= UP) {
3579 if (init_cache_random_seq(s))
3583 if (!init_kmem_cache_nodes(s))
3586 if (alloc_kmem_cache_cpus(s))
3589 free_kmem_cache_nodes(s);
3591 if (flags & SLAB_PANIC)
3592 panic("Cannot create slab %s size=%lu realsize=%u order=%u offset=%u flags=%lx\n",
3593 s->name, (unsigned long)s->size, s->size,
3594 oo_order(s->oo), s->offset, flags);
3598 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3601 #ifdef CONFIG_SLUB_DEBUG
3602 void *addr = page_address(page);
3604 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3605 sizeof(long), GFP_ATOMIC);
3608 slab_err(s, page, text, s->name);
3611 get_map(s, page, map);
3612 for_each_object(p, s, addr, page->objects) {
3614 if (!test_bit(slab_index(p, s, addr), map)) {
3615 pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3616 print_tracking(s, p);
3625 * Attempt to free all partial slabs on a node.
3626 * This is called from __kmem_cache_shutdown(). We must take list_lock
3627 * because sysfs file might still access partial list after the shutdowning.
3629 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3631 struct page *page, *h;
3633 BUG_ON(irqs_disabled());
3634 spin_lock_irq(&n->list_lock);
3635 list_for_each_entry_safe(page, h, &n->partial, lru) {
3637 remove_partial(n, page);
3638 discard_slab(s, page);
3640 list_slab_objects(s, page,
3641 "Objects remaining in %s on __kmem_cache_shutdown()");
3644 spin_unlock_irq(&n->list_lock);
3648 * Release all resources used by a slab cache.
3650 int __kmem_cache_shutdown(struct kmem_cache *s)
3653 struct kmem_cache_node *n;
3656 /* Attempt to free all objects */
3657 for_each_kmem_cache_node(s, node, n) {
3659 if (n->nr_partial || slabs_node(s, node))
3665 /********************************************************************
3667 *******************************************************************/
3669 static int __init setup_slub_min_order(char *str)
3671 get_option(&str, &slub_min_order);
3676 __setup("slub_min_order=", setup_slub_min_order);
3678 static int __init setup_slub_max_order(char *str)
3680 get_option(&str, &slub_max_order);
3681 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3686 __setup("slub_max_order=", setup_slub_max_order);
3688 static int __init setup_slub_min_objects(char *str)
3690 get_option(&str, &slub_min_objects);
3695 __setup("slub_min_objects=", setup_slub_min_objects);
3697 void *__kmalloc(size_t size, gfp_t flags)
3699 struct kmem_cache *s;
3702 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3703 return kmalloc_large(size, flags);
3705 s = kmalloc_slab(size, flags);
3707 if (unlikely(ZERO_OR_NULL_PTR(s)))
3710 ret = slab_alloc(s, flags, _RET_IP_);
3712 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3714 kasan_kmalloc(s, ret, size, flags);
3718 EXPORT_SYMBOL(__kmalloc);
3721 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3726 flags |= __GFP_COMP | __GFP_NOTRACK;
3727 page = alloc_pages_node(node, flags, get_order(size));
3729 ptr = page_address(page);
3731 kmalloc_large_node_hook(ptr, size, flags);
3735 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3737 struct kmem_cache *s;
3740 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3741 ret = kmalloc_large_node(size, flags, node);
3743 trace_kmalloc_node(_RET_IP_, ret,
3744 size, PAGE_SIZE << get_order(size),
3750 s = kmalloc_slab(size, flags);
3752 if (unlikely(ZERO_OR_NULL_PTR(s)))
3755 ret = slab_alloc_node(s, flags, node, _RET_IP_);
3757 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3759 kasan_kmalloc(s, ret, size, flags);
3763 EXPORT_SYMBOL(__kmalloc_node);
3766 static size_t __ksize(const void *object)
3770 if (unlikely(object == ZERO_SIZE_PTR))
3773 page = virt_to_head_page(object);
3775 if (unlikely(!PageSlab(page))) {
3776 WARN_ON(!PageCompound(page));
3777 return PAGE_SIZE << compound_order(page);
3780 return slab_ksize(page->slab_cache);
3783 size_t ksize(const void *object)
3785 size_t size = __ksize(object);
3786 /* We assume that ksize callers could use whole allocated area,
3787 * so we need to unpoison this area.
3789 kasan_unpoison_shadow(object, size);
3792 EXPORT_SYMBOL(ksize);
3794 void kfree(const void *x)
3797 void *object = (void *)x;
3799 trace_kfree(_RET_IP_, x);
3801 if (unlikely(ZERO_OR_NULL_PTR(x)))
3804 page = virt_to_head_page(x);
3805 if (unlikely(!PageSlab(page))) {
3806 BUG_ON(!PageCompound(page));
3808 __free_pages(page, compound_order(page));
3811 slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3813 EXPORT_SYMBOL(kfree);
3815 #define SHRINK_PROMOTE_MAX 32
3818 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3819 * up most to the head of the partial lists. New allocations will then
3820 * fill those up and thus they can be removed from the partial lists.
3822 * The slabs with the least items are placed last. This results in them
3823 * being allocated from last increasing the chance that the last objects
3824 * are freed in them.
3826 int __kmem_cache_shrink(struct kmem_cache *s, bool deactivate)
3830 struct kmem_cache_node *n;
3833 struct list_head discard;
3834 struct list_head promote[SHRINK_PROMOTE_MAX];
3835 unsigned long flags;
3840 * Disable empty slabs caching. Used to avoid pinning offline
3841 * memory cgroups by kmem pages that can be freed.
3847 * s->cpu_partial is checked locklessly (see put_cpu_partial),
3848 * so we have to make sure the change is visible.
3850 synchronize_sched();
3854 for_each_kmem_cache_node(s, node, n) {
3855 INIT_LIST_HEAD(&discard);
3856 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3857 INIT_LIST_HEAD(promote + i);
3859 spin_lock_irqsave(&n->list_lock, flags);
3862 * Build lists of slabs to discard or promote.
3864 * Note that concurrent frees may occur while we hold the
3865 * list_lock. page->inuse here is the upper limit.
3867 list_for_each_entry_safe(page, t, &n->partial, lru) {
3868 int free = page->objects - page->inuse;
3870 /* Do not reread page->inuse */
3873 /* We do not keep full slabs on the list */
3876 if (free == page->objects) {
3877 list_move(&page->lru, &discard);
3879 } else if (free <= SHRINK_PROMOTE_MAX)
3880 list_move(&page->lru, promote + free - 1);
3884 * Promote the slabs filled up most to the head of the
3887 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
3888 list_splice(promote + i, &n->partial);
3890 spin_unlock_irqrestore(&n->list_lock, flags);
3892 /* Release empty slabs */
3893 list_for_each_entry_safe(page, t, &discard, lru)
3894 discard_slab(s, page);
3896 if (slabs_node(s, node))
3903 static int slab_mem_going_offline_callback(void *arg)
3905 struct kmem_cache *s;
3907 mutex_lock(&slab_mutex);
3908 list_for_each_entry(s, &slab_caches, list)
3909 __kmem_cache_shrink(s, false);
3910 mutex_unlock(&slab_mutex);
3915 static void slab_mem_offline_callback(void *arg)
3917 struct kmem_cache_node *n;
3918 struct kmem_cache *s;
3919 struct memory_notify *marg = arg;
3922 offline_node = marg->status_change_nid_normal;
3925 * If the node still has available memory. we need kmem_cache_node
3928 if (offline_node < 0)
3931 mutex_lock(&slab_mutex);
3932 list_for_each_entry(s, &slab_caches, list) {
3933 n = get_node(s, offline_node);
3936 * if n->nr_slabs > 0, slabs still exist on the node
3937 * that is going down. We were unable to free them,
3938 * and offline_pages() function shouldn't call this
3939 * callback. So, we must fail.
3941 BUG_ON(slabs_node(s, offline_node));
3943 s->node[offline_node] = NULL;
3944 kmem_cache_free(kmem_cache_node, n);
3947 mutex_unlock(&slab_mutex);
3950 static int slab_mem_going_online_callback(void *arg)
3952 struct kmem_cache_node *n;
3953 struct kmem_cache *s;
3954 struct memory_notify *marg = arg;
3955 int nid = marg->status_change_nid_normal;
3959 * If the node's memory is already available, then kmem_cache_node is
3960 * already created. Nothing to do.
3966 * We are bringing a node online. No memory is available yet. We must
3967 * allocate a kmem_cache_node structure in order to bring the node
3970 mutex_lock(&slab_mutex);
3971 list_for_each_entry(s, &slab_caches, list) {
3973 * XXX: kmem_cache_alloc_node will fallback to other nodes
3974 * since memory is not yet available from the node that
3977 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3982 init_kmem_cache_node(n);
3986 mutex_unlock(&slab_mutex);
3990 static int slab_memory_callback(struct notifier_block *self,
3991 unsigned long action, void *arg)
3996 case MEM_GOING_ONLINE:
3997 ret = slab_mem_going_online_callback(arg);
3999 case MEM_GOING_OFFLINE:
4000 ret = slab_mem_going_offline_callback(arg);
4003 case MEM_CANCEL_ONLINE:
4004 slab_mem_offline_callback(arg);
4007 case MEM_CANCEL_OFFLINE:
4011 ret = notifier_from_errno(ret);
4017 static struct notifier_block slab_memory_callback_nb = {
4018 .notifier_call = slab_memory_callback,
4019 .priority = SLAB_CALLBACK_PRI,
4022 /********************************************************************
4023 * Basic setup of slabs
4024 *******************************************************************/
4027 * Used for early kmem_cache structures that were allocated using
4028 * the page allocator. Allocate them properly then fix up the pointers
4029 * that may be pointing to the wrong kmem_cache structure.
4032 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4035 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4036 struct kmem_cache_node *n;
4038 memcpy(s, static_cache, kmem_cache->object_size);
4041 * This runs very early, and only the boot processor is supposed to be
4042 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4045 __flush_cpu_slab(s, smp_processor_id());
4046 for_each_kmem_cache_node(s, node, n) {
4049 list_for_each_entry(p, &n->partial, lru)
4052 #ifdef CONFIG_SLUB_DEBUG
4053 list_for_each_entry(p, &n->full, lru)
4057 slab_init_memcg_params(s);
4058 list_add(&s->list, &slab_caches);
4062 void __init kmem_cache_init(void)
4064 static __initdata struct kmem_cache boot_kmem_cache,
4065 boot_kmem_cache_node;
4067 if (debug_guardpage_minorder())
4070 kmem_cache_node = &boot_kmem_cache_node;
4071 kmem_cache = &boot_kmem_cache;
4073 create_boot_cache(kmem_cache_node, "kmem_cache_node",
4074 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
4076 register_hotmemory_notifier(&slab_memory_callback_nb);
4078 /* Able to allocate the per node structures */
4079 slab_state = PARTIAL;
4081 create_boot_cache(kmem_cache, "kmem_cache",
4082 offsetof(struct kmem_cache, node) +
4083 nr_node_ids * sizeof(struct kmem_cache_node *),
4084 SLAB_HWCACHE_ALIGN);
4086 kmem_cache = bootstrap(&boot_kmem_cache);
4089 * Allocate kmem_cache_node properly from the kmem_cache slab.
4090 * kmem_cache_node is separately allocated so no need to
4091 * update any list pointers.
4093 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4095 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4096 setup_kmalloc_cache_index_table();
4097 create_kmalloc_caches(0);
4099 /* Setup random freelists for each cache */
4100 init_freelist_randomization();
4103 register_cpu_notifier(&slab_notifier);
4106 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
4108 slub_min_order, slub_max_order, slub_min_objects,
4109 nr_cpu_ids, nr_node_ids);
4112 void __init kmem_cache_init_late(void)
4117 __kmem_cache_alias(const char *name, size_t size, size_t align,
4118 unsigned long flags, void (*ctor)(void *))
4120 struct kmem_cache *s, *c;
4122 s = find_mergeable(size, align, flags, name, ctor);
4127 * Adjust the object sizes so that we clear
4128 * the complete object on kzalloc.
4130 s->object_size = max(s->object_size, (int)size);
4131 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
4133 for_each_memcg_cache(c, s) {
4134 c->object_size = s->object_size;
4135 c->inuse = max_t(int, c->inuse,
4136 ALIGN(size, sizeof(void *)));
4139 if (sysfs_slab_alias(s, name)) {
4148 int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
4152 err = kmem_cache_open(s, flags);
4156 /* Mutex is not taken during early boot */
4157 if (slab_state <= UP)
4160 memcg_propagate_slab_attrs(s);
4161 err = sysfs_slab_add(s);
4163 __kmem_cache_release(s);
4170 * Use the cpu notifier to insure that the cpu slabs are flushed when
4173 static int slab_cpuup_callback(struct notifier_block *nfb,
4174 unsigned long action, void *hcpu)
4176 long cpu = (long)hcpu;
4177 struct kmem_cache *s;
4178 unsigned long flags;
4181 case CPU_UP_CANCELED:
4182 case CPU_UP_CANCELED_FROZEN:
4184 case CPU_DEAD_FROZEN:
4185 mutex_lock(&slab_mutex);
4186 list_for_each_entry(s, &slab_caches, list) {
4187 local_irq_save(flags);
4188 __flush_cpu_slab(s, cpu);
4189 local_irq_restore(flags);
4191 mutex_unlock(&slab_mutex);
4199 static struct notifier_block slab_notifier = {
4200 .notifier_call = slab_cpuup_callback
4205 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4207 struct kmem_cache *s;
4210 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4211 return kmalloc_large(size, gfpflags);
4213 s = kmalloc_slab(size, gfpflags);
4215 if (unlikely(ZERO_OR_NULL_PTR(s)))
4218 ret = slab_alloc(s, gfpflags, caller);
4220 /* Honor the call site pointer we received. */
4221 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4227 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4228 int node, unsigned long caller)
4230 struct kmem_cache *s;
4233 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4234 ret = kmalloc_large_node(size, gfpflags, node);
4236 trace_kmalloc_node(caller, ret,
4237 size, PAGE_SIZE << get_order(size),
4243 s = kmalloc_slab(size, gfpflags);
4245 if (unlikely(ZERO_OR_NULL_PTR(s)))
4248 ret = slab_alloc_node(s, gfpflags, node, caller);
4250 /* Honor the call site pointer we received. */
4251 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4258 static int count_inuse(struct page *page)
4263 static int count_total(struct page *page)
4265 return page->objects;
4269 #ifdef CONFIG_SLUB_DEBUG
4270 static int validate_slab(struct kmem_cache *s, struct page *page,
4274 void *addr = page_address(page);
4276 if (!check_slab(s, page) ||
4277 !on_freelist(s, page, NULL))
4280 /* Now we know that a valid freelist exists */
4281 bitmap_zero(map, page->objects);
4283 get_map(s, page, map);
4284 for_each_object(p, s, addr, page->objects) {
4285 if (test_bit(slab_index(p, s, addr), map))
4286 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4290 for_each_object(p, s, addr, page->objects)
4291 if (!test_bit(slab_index(p, s, addr), map))
4292 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4297 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4301 validate_slab(s, page, map);
4305 static int validate_slab_node(struct kmem_cache *s,
4306 struct kmem_cache_node *n, unsigned long *map)
4308 unsigned long count = 0;
4310 unsigned long flags;
4312 spin_lock_irqsave(&n->list_lock, flags);
4314 list_for_each_entry(page, &n->partial, lru) {
4315 validate_slab_slab(s, page, map);
4318 if (count != n->nr_partial)
4319 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4320 s->name, count, n->nr_partial);
4322 if (!(s->flags & SLAB_STORE_USER))
4325 list_for_each_entry(page, &n->full, lru) {
4326 validate_slab_slab(s, page, map);
4329 if (count != atomic_long_read(&n->nr_slabs))
4330 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4331 s->name, count, atomic_long_read(&n->nr_slabs));
4334 spin_unlock_irqrestore(&n->list_lock, flags);
4338 static long validate_slab_cache(struct kmem_cache *s)
4341 unsigned long count = 0;
4342 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4343 sizeof(unsigned long), GFP_KERNEL);
4344 struct kmem_cache_node *n;
4350 for_each_kmem_cache_node(s, node, n)
4351 count += validate_slab_node(s, n, map);
4356 * Generate lists of code addresses where slabcache objects are allocated
4361 unsigned long count;
4368 DECLARE_BITMAP(cpus, NR_CPUS);
4374 unsigned long count;
4375 struct location *loc;
4378 static void free_loc_track(struct loc_track *t)
4381 free_pages((unsigned long)t->loc,
4382 get_order(sizeof(struct location) * t->max));
4385 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4390 order = get_order(sizeof(struct location) * max);
4392 l = (void *)__get_free_pages(flags, order);
4397 memcpy(l, t->loc, sizeof(struct location) * t->count);
4405 static int add_location(struct loc_track *t, struct kmem_cache *s,
4406 const struct track *track)
4408 long start, end, pos;
4410 unsigned long caddr;
4411 unsigned long age = jiffies - track->when;
4417 pos = start + (end - start + 1) / 2;
4420 * There is nothing at "end". If we end up there
4421 * we need to add something to before end.
4426 caddr = t->loc[pos].addr;
4427 if (track->addr == caddr) {
4433 if (age < l->min_time)
4435 if (age > l->max_time)
4438 if (track->pid < l->min_pid)
4439 l->min_pid = track->pid;
4440 if (track->pid > l->max_pid)
4441 l->max_pid = track->pid;
4443 cpumask_set_cpu(track->cpu,
4444 to_cpumask(l->cpus));
4446 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4450 if (track->addr < caddr)
4457 * Not found. Insert new tracking element.
4459 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4465 (t->count - pos) * sizeof(struct location));
4468 l->addr = track->addr;
4472 l->min_pid = track->pid;
4473 l->max_pid = track->pid;
4474 cpumask_clear(to_cpumask(l->cpus));
4475 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4476 nodes_clear(l->nodes);
4477 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4481 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4482 struct page *page, enum track_item alloc,
4485 void *addr = page_address(page);
4488 bitmap_zero(map, page->objects);
4489 get_map(s, page, map);
4491 for_each_object(p, s, addr, page->objects)
4492 if (!test_bit(slab_index(p, s, addr), map))
4493 add_location(t, s, get_track(s, p, alloc));
4496 static int list_locations(struct kmem_cache *s, char *buf,
4497 enum track_item alloc)
4501 struct loc_track t = { 0, 0, NULL };
4503 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4504 sizeof(unsigned long), GFP_KERNEL);
4505 struct kmem_cache_node *n;
4507 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4510 return sprintf(buf, "Out of memory\n");
4512 /* Push back cpu slabs */
4515 for_each_kmem_cache_node(s, node, n) {
4516 unsigned long flags;
4519 if (!atomic_long_read(&n->nr_slabs))
4522 spin_lock_irqsave(&n->list_lock, flags);
4523 list_for_each_entry(page, &n->partial, lru)
4524 process_slab(&t, s, page, alloc, map);
4525 list_for_each_entry(page, &n->full, lru)
4526 process_slab(&t, s, page, alloc, map);
4527 spin_unlock_irqrestore(&n->list_lock, flags);
4530 for (i = 0; i < t.count; i++) {
4531 struct location *l = &t.loc[i];
4533 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4535 len += sprintf(buf + len, "%7ld ", l->count);
4538 len += sprintf(buf + len, "%pS", (void *)l->addr);
4540 len += sprintf(buf + len, "<not-available>");
4542 if (l->sum_time != l->min_time) {
4543 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4545 (long)div_u64(l->sum_time, l->count),
4548 len += sprintf(buf + len, " age=%ld",
4551 if (l->min_pid != l->max_pid)
4552 len += sprintf(buf + len, " pid=%ld-%ld",
4553 l->min_pid, l->max_pid);
4555 len += sprintf(buf + len, " pid=%ld",
4558 if (num_online_cpus() > 1 &&
4559 !cpumask_empty(to_cpumask(l->cpus)) &&
4560 len < PAGE_SIZE - 60)
4561 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4563 cpumask_pr_args(to_cpumask(l->cpus)));
4565 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4566 len < PAGE_SIZE - 60)
4567 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4569 nodemask_pr_args(&l->nodes));
4571 len += sprintf(buf + len, "\n");
4577 len += sprintf(buf, "No data\n");
4582 #ifdef SLUB_RESILIENCY_TEST
4583 static void __init resiliency_test(void)
4587 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4589 pr_err("SLUB resiliency testing\n");
4590 pr_err("-----------------------\n");
4591 pr_err("A. Corruption after allocation\n");
4593 p = kzalloc(16, GFP_KERNEL);
4595 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4598 validate_slab_cache(kmalloc_caches[4]);
4600 /* Hmmm... The next two are dangerous */
4601 p = kzalloc(32, GFP_KERNEL);
4602 p[32 + sizeof(void *)] = 0x34;
4603 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4605 pr_err("If allocated object is overwritten then not detectable\n\n");
4607 validate_slab_cache(kmalloc_caches[5]);
4608 p = kzalloc(64, GFP_KERNEL);
4609 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4611 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4613 pr_err("If allocated object is overwritten then not detectable\n\n");
4614 validate_slab_cache(kmalloc_caches[6]);
4616 pr_err("\nB. Corruption after free\n");
4617 p = kzalloc(128, GFP_KERNEL);
4620 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4621 validate_slab_cache(kmalloc_caches[7]);
4623 p = kzalloc(256, GFP_KERNEL);
4626 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4627 validate_slab_cache(kmalloc_caches[8]);
4629 p = kzalloc(512, GFP_KERNEL);
4632 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4633 validate_slab_cache(kmalloc_caches[9]);
4637 static void resiliency_test(void) {};
4642 enum slab_stat_type {
4643 SL_ALL, /* All slabs */
4644 SL_PARTIAL, /* Only partially allocated slabs */
4645 SL_CPU, /* Only slabs used for cpu caches */
4646 SL_OBJECTS, /* Determine allocated objects not slabs */
4647 SL_TOTAL /* Determine object capacity not slabs */
4650 #define SO_ALL (1 << SL_ALL)
4651 #define SO_PARTIAL (1 << SL_PARTIAL)
4652 #define SO_CPU (1 << SL_CPU)
4653 #define SO_OBJECTS (1 << SL_OBJECTS)
4654 #define SO_TOTAL (1 << SL_TOTAL)
4656 static ssize_t show_slab_objects(struct kmem_cache *s,
4657 char *buf, unsigned long flags)
4659 unsigned long total = 0;
4662 unsigned long *nodes;
4664 nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4668 if (flags & SO_CPU) {
4671 for_each_possible_cpu(cpu) {
4672 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4677 page = READ_ONCE(c->page);
4681 node = page_to_nid(page);
4682 if (flags & SO_TOTAL)
4684 else if (flags & SO_OBJECTS)
4692 page = READ_ONCE(c->partial);
4694 node = page_to_nid(page);
4695 if (flags & SO_TOTAL)
4697 else if (flags & SO_OBJECTS)
4708 #ifdef CONFIG_SLUB_DEBUG
4709 if (flags & SO_ALL) {
4710 struct kmem_cache_node *n;
4712 for_each_kmem_cache_node(s, node, n) {
4714 if (flags & SO_TOTAL)
4715 x = atomic_long_read(&n->total_objects);
4716 else if (flags & SO_OBJECTS)
4717 x = atomic_long_read(&n->total_objects) -
4718 count_partial(n, count_free);
4720 x = atomic_long_read(&n->nr_slabs);
4727 if (flags & SO_PARTIAL) {
4728 struct kmem_cache_node *n;
4730 for_each_kmem_cache_node(s, node, n) {
4731 if (flags & SO_TOTAL)
4732 x = count_partial(n, count_total);
4733 else if (flags & SO_OBJECTS)
4734 x = count_partial(n, count_inuse);
4741 x = sprintf(buf, "%lu", total);
4743 for (node = 0; node < nr_node_ids; node++)
4745 x += sprintf(buf + x, " N%d=%lu",
4750 return x + sprintf(buf + x, "\n");
4753 #ifdef CONFIG_SLUB_DEBUG
4754 static int any_slab_objects(struct kmem_cache *s)
4757 struct kmem_cache_node *n;
4759 for_each_kmem_cache_node(s, node, n)
4760 if (atomic_long_read(&n->total_objects))
4767 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4768 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4770 struct slab_attribute {
4771 struct attribute attr;
4772 ssize_t (*show)(struct kmem_cache *s, char *buf);
4773 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4776 #define SLAB_ATTR_RO(_name) \
4777 static struct slab_attribute _name##_attr = \
4778 __ATTR(_name, 0400, _name##_show, NULL)
4780 #define SLAB_ATTR(_name) \
4781 static struct slab_attribute _name##_attr = \
4782 __ATTR(_name, 0600, _name##_show, _name##_store)
4784 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4786 return sprintf(buf, "%d\n", s->size);
4788 SLAB_ATTR_RO(slab_size);
4790 static ssize_t align_show(struct kmem_cache *s, char *buf)
4792 return sprintf(buf, "%d\n", s->align);
4794 SLAB_ATTR_RO(align);
4796 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4798 return sprintf(buf, "%d\n", s->object_size);
4800 SLAB_ATTR_RO(object_size);
4802 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4804 return sprintf(buf, "%d\n", oo_objects(s->oo));
4806 SLAB_ATTR_RO(objs_per_slab);
4808 static ssize_t order_store(struct kmem_cache *s,
4809 const char *buf, size_t length)
4811 unsigned long order;
4814 err = kstrtoul(buf, 10, &order);
4818 if (order > slub_max_order || order < slub_min_order)
4821 calculate_sizes(s, order);
4825 static ssize_t order_show(struct kmem_cache *s, char *buf)
4827 return sprintf(buf, "%d\n", oo_order(s->oo));
4831 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4833 return sprintf(buf, "%lu\n", s->min_partial);
4836 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4842 err = kstrtoul(buf, 10, &min);
4846 set_min_partial(s, min);
4849 SLAB_ATTR(min_partial);
4851 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4853 return sprintf(buf, "%u\n", s->cpu_partial);
4856 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4859 unsigned long objects;
4862 err = kstrtoul(buf, 10, &objects);
4865 if (objects && !kmem_cache_has_cpu_partial(s))
4868 s->cpu_partial = objects;
4872 SLAB_ATTR(cpu_partial);
4874 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4878 return sprintf(buf, "%pS\n", s->ctor);
4882 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4884 return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
4886 SLAB_ATTR_RO(aliases);
4888 static ssize_t partial_show(struct kmem_cache *s, char *buf)
4890 return show_slab_objects(s, buf, SO_PARTIAL);
4892 SLAB_ATTR_RO(partial);
4894 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4896 return show_slab_objects(s, buf, SO_CPU);
4898 SLAB_ATTR_RO(cpu_slabs);
4900 static ssize_t objects_show(struct kmem_cache *s, char *buf)
4902 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4904 SLAB_ATTR_RO(objects);
4906 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4908 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4910 SLAB_ATTR_RO(objects_partial);
4912 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4919 for_each_online_cpu(cpu) {
4920 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4923 pages += page->pages;
4924 objects += page->pobjects;
4928 len = sprintf(buf, "%d(%d)", objects, pages);
4931 for_each_online_cpu(cpu) {
4932 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4934 if (page && len < PAGE_SIZE - 20)
4935 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4936 page->pobjects, page->pages);
4939 return len + sprintf(buf + len, "\n");
4941 SLAB_ATTR_RO(slabs_cpu_partial);
4943 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4945 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4948 static ssize_t reclaim_account_store(struct kmem_cache *s,
4949 const char *buf, size_t length)
4951 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4953 s->flags |= SLAB_RECLAIM_ACCOUNT;
4956 SLAB_ATTR(reclaim_account);
4958 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4960 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4962 SLAB_ATTR_RO(hwcache_align);
4964 #ifdef CONFIG_ZONE_DMA
4965 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4967 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4969 SLAB_ATTR_RO(cache_dma);
4972 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4974 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4976 SLAB_ATTR_RO(destroy_by_rcu);
4978 static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4980 return sprintf(buf, "%d\n", s->reserved);
4982 SLAB_ATTR_RO(reserved);
4984 #ifdef CONFIG_SLUB_DEBUG
4985 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4987 return show_slab_objects(s, buf, SO_ALL);
4989 SLAB_ATTR_RO(slabs);
4991 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4993 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4995 SLAB_ATTR_RO(total_objects);
4997 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4999 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5002 static ssize_t sanity_checks_store(struct kmem_cache *s,
5003 const char *buf, size_t length)
5005 s->flags &= ~SLAB_CONSISTENCY_CHECKS;
5006 if (buf[0] == '1') {
5007 s->flags &= ~__CMPXCHG_DOUBLE;
5008 s->flags |= SLAB_CONSISTENCY_CHECKS;
5012 SLAB_ATTR(sanity_checks);
5014 static ssize_t trace_show(struct kmem_cache *s, char *buf)
5016 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5019 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
5023 * Tracing a merged cache is going to give confusing results
5024 * as well as cause other issues like converting a mergeable
5025 * cache into an umergeable one.
5027 if (s->refcount > 1)
5030 s->flags &= ~SLAB_TRACE;
5031 if (buf[0] == '1') {
5032 s->flags &= ~__CMPXCHG_DOUBLE;
5033 s->flags |= SLAB_TRACE;
5039 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5041 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5044 static ssize_t red_zone_store(struct kmem_cache *s,
5045 const char *buf, size_t length)
5047 if (any_slab_objects(s))
5050 s->flags &= ~SLAB_RED_ZONE;
5051 if (buf[0] == '1') {
5052 s->flags |= SLAB_RED_ZONE;
5054 calculate_sizes(s, -1);
5057 SLAB_ATTR(red_zone);
5059 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5061 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5064 static ssize_t poison_store(struct kmem_cache *s,
5065 const char *buf, size_t length)
5067 if (any_slab_objects(s))
5070 s->flags &= ~SLAB_POISON;
5071 if (buf[0] == '1') {
5072 s->flags |= SLAB_POISON;
5074 calculate_sizes(s, -1);
5079 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5081 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5084 static ssize_t store_user_store(struct kmem_cache *s,
5085 const char *buf, size_t length)
5087 if (any_slab_objects(s))
5090 s->flags &= ~SLAB_STORE_USER;
5091 if (buf[0] == '1') {
5092 s->flags &= ~__CMPXCHG_DOUBLE;
5093 s->flags |= SLAB_STORE_USER;
5095 calculate_sizes(s, -1);
5098 SLAB_ATTR(store_user);
5100 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5105 static ssize_t validate_store(struct kmem_cache *s,
5106 const char *buf, size_t length)
5110 if (buf[0] == '1') {
5111 ret = validate_slab_cache(s);
5117 SLAB_ATTR(validate);
5119 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5121 if (!(s->flags & SLAB_STORE_USER))
5123 return list_locations(s, buf, TRACK_ALLOC);
5125 SLAB_ATTR_RO(alloc_calls);
5127 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5129 if (!(s->flags & SLAB_STORE_USER))
5131 return list_locations(s, buf, TRACK_FREE);
5133 SLAB_ATTR_RO(free_calls);
5134 #endif /* CONFIG_SLUB_DEBUG */
5136 #ifdef CONFIG_FAILSLAB
5137 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5139 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5142 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5145 if (s->refcount > 1)
5148 s->flags &= ~SLAB_FAILSLAB;
5150 s->flags |= SLAB_FAILSLAB;
5153 SLAB_ATTR(failslab);
5156 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5161 static ssize_t shrink_store(struct kmem_cache *s,
5162 const char *buf, size_t length)
5165 kmem_cache_shrink(s);
5173 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5175 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
5178 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5179 const char *buf, size_t length)
5181 unsigned long ratio;
5184 err = kstrtoul(buf, 10, &ratio);
5189 s->remote_node_defrag_ratio = ratio * 10;
5193 SLAB_ATTR(remote_node_defrag_ratio);
5196 #ifdef CONFIG_SLUB_STATS
5197 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5199 unsigned long sum = 0;
5202 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5207 for_each_online_cpu(cpu) {
5208 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5214 len = sprintf(buf, "%lu", sum);
5217 for_each_online_cpu(cpu) {
5218 if (data[cpu] && len < PAGE_SIZE - 20)
5219 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5223 return len + sprintf(buf + len, "\n");
5226 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5230 for_each_online_cpu(cpu)
5231 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5234 #define STAT_ATTR(si, text) \
5235 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5237 return show_stat(s, buf, si); \
5239 static ssize_t text##_store(struct kmem_cache *s, \
5240 const char *buf, size_t length) \
5242 if (buf[0] != '0') \
5244 clear_stat(s, si); \
5249 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5250 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5251 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5252 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5253 STAT_ATTR(FREE_FROZEN, free_frozen);
5254 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5255 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5256 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5257 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5258 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5259 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5260 STAT_ATTR(FREE_SLAB, free_slab);
5261 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5262 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5263 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5264 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5265 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5266 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5267 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5268 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5269 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5270 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5271 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5272 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5273 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5274 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5277 static struct attribute *slab_attrs[] = {
5278 &slab_size_attr.attr,
5279 &object_size_attr.attr,
5280 &objs_per_slab_attr.attr,
5282 &min_partial_attr.attr,
5283 &cpu_partial_attr.attr,
5285 &objects_partial_attr.attr,
5287 &cpu_slabs_attr.attr,
5291 &hwcache_align_attr.attr,
5292 &reclaim_account_attr.attr,
5293 &destroy_by_rcu_attr.attr,
5295 &reserved_attr.attr,
5296 &slabs_cpu_partial_attr.attr,
5297 #ifdef CONFIG_SLUB_DEBUG
5298 &total_objects_attr.attr,
5300 &sanity_checks_attr.attr,
5302 &red_zone_attr.attr,
5304 &store_user_attr.attr,
5305 &validate_attr.attr,
5306 &alloc_calls_attr.attr,
5307 &free_calls_attr.attr,
5309 #ifdef CONFIG_ZONE_DMA
5310 &cache_dma_attr.attr,
5313 &remote_node_defrag_ratio_attr.attr,
5315 #ifdef CONFIG_SLUB_STATS
5316 &alloc_fastpath_attr.attr,
5317 &alloc_slowpath_attr.attr,
5318 &free_fastpath_attr.attr,
5319 &free_slowpath_attr.attr,
5320 &free_frozen_attr.attr,
5321 &free_add_partial_attr.attr,
5322 &free_remove_partial_attr.attr,
5323 &alloc_from_partial_attr.attr,
5324 &alloc_slab_attr.attr,
5325 &alloc_refill_attr.attr,
5326 &alloc_node_mismatch_attr.attr,
5327 &free_slab_attr.attr,
5328 &cpuslab_flush_attr.attr,
5329 &deactivate_full_attr.attr,
5330 &deactivate_empty_attr.attr,
5331 &deactivate_to_head_attr.attr,
5332 &deactivate_to_tail_attr.attr,
5333 &deactivate_remote_frees_attr.attr,
5334 &deactivate_bypass_attr.attr,
5335 &order_fallback_attr.attr,
5336 &cmpxchg_double_fail_attr.attr,
5337 &cmpxchg_double_cpu_fail_attr.attr,
5338 &cpu_partial_alloc_attr.attr,
5339 &cpu_partial_free_attr.attr,
5340 &cpu_partial_node_attr.attr,
5341 &cpu_partial_drain_attr.attr,
5343 #ifdef CONFIG_FAILSLAB
5344 &failslab_attr.attr,
5350 static struct attribute_group slab_attr_group = {
5351 .attrs = slab_attrs,
5354 static ssize_t slab_attr_show(struct kobject *kobj,
5355 struct attribute *attr,
5358 struct slab_attribute *attribute;
5359 struct kmem_cache *s;
5362 attribute = to_slab_attr(attr);
5365 if (!attribute->show)
5368 err = attribute->show(s, buf);
5373 static ssize_t slab_attr_store(struct kobject *kobj,
5374 struct attribute *attr,
5375 const char *buf, size_t len)
5377 struct slab_attribute *attribute;
5378 struct kmem_cache *s;
5381 attribute = to_slab_attr(attr);
5384 if (!attribute->store)
5387 err = attribute->store(s, buf, len);
5389 if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5390 struct kmem_cache *c;
5392 mutex_lock(&slab_mutex);
5393 if (s->max_attr_size < len)
5394 s->max_attr_size = len;
5397 * This is a best effort propagation, so this function's return
5398 * value will be determined by the parent cache only. This is
5399 * basically because not all attributes will have a well
5400 * defined semantics for rollbacks - most of the actions will
5401 * have permanent effects.
5403 * Returning the error value of any of the children that fail
5404 * is not 100 % defined, in the sense that users seeing the
5405 * error code won't be able to know anything about the state of
5408 * Only returning the error code for the parent cache at least
5409 * has well defined semantics. The cache being written to
5410 * directly either failed or succeeded, in which case we loop
5411 * through the descendants with best-effort propagation.
5413 for_each_memcg_cache(c, s)
5414 attribute->store(c, buf, len);
5415 mutex_unlock(&slab_mutex);
5421 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5425 char *buffer = NULL;
5426 struct kmem_cache *root_cache;
5428 if (is_root_cache(s))
5431 root_cache = s->memcg_params.root_cache;
5434 * This mean this cache had no attribute written. Therefore, no point
5435 * in copying default values around
5437 if (!root_cache->max_attr_size)
5440 for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5443 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5445 if (!attr || !attr->store || !attr->show)
5449 * It is really bad that we have to allocate here, so we will
5450 * do it only as a fallback. If we actually allocate, though,
5451 * we can just use the allocated buffer until the end.
5453 * Most of the slub attributes will tend to be very small in
5454 * size, but sysfs allows buffers up to a page, so they can
5455 * theoretically happen.
5459 else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5462 buffer = (char *) get_zeroed_page(GFP_KERNEL);
5463 if (WARN_ON(!buffer))
5468 attr->show(root_cache, buf);
5469 attr->store(s, buf, strlen(buf));
5473 free_page((unsigned long)buffer);
5477 static void kmem_cache_release(struct kobject *k)
5479 slab_kmem_cache_release(to_slab(k));
5482 static const struct sysfs_ops slab_sysfs_ops = {
5483 .show = slab_attr_show,
5484 .store = slab_attr_store,
5487 static struct kobj_type slab_ktype = {
5488 .sysfs_ops = &slab_sysfs_ops,
5489 .release = kmem_cache_release,
5492 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5494 struct kobj_type *ktype = get_ktype(kobj);
5496 if (ktype == &slab_ktype)
5501 static const struct kset_uevent_ops slab_uevent_ops = {
5502 .filter = uevent_filter,
5505 static struct kset *slab_kset;
5507 static inline struct kset *cache_kset(struct kmem_cache *s)
5510 if (!is_root_cache(s))
5511 return s->memcg_params.root_cache->memcg_kset;
5516 #define ID_STR_LENGTH 64
5518 /* Create a unique string id for a slab cache:
5520 * Format :[flags-]size
5522 static char *create_unique_id(struct kmem_cache *s)
5524 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5531 * First flags affecting slabcache operations. We will only
5532 * get here for aliasable slabs so we do not need to support
5533 * too many flags. The flags here must cover all flags that
5534 * are matched during merging to guarantee that the id is
5537 if (s->flags & SLAB_CACHE_DMA)
5539 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5541 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5543 if (!(s->flags & SLAB_NOTRACK))
5545 if (s->flags & SLAB_ACCOUNT)
5549 p += sprintf(p, "%07d", s->size);
5551 BUG_ON(p > name + ID_STR_LENGTH - 1);
5555 static int sysfs_slab_add(struct kmem_cache *s)
5559 int unmergeable = slab_unmergeable(s);
5563 * Slabcache can never be merged so we can use the name proper.
5564 * This is typically the case for debug situations. In that
5565 * case we can catch duplicate names easily.
5567 sysfs_remove_link(&slab_kset->kobj, s->name);
5571 * Create a unique name for the slab as a target
5574 name = create_unique_id(s);
5577 s->kobj.kset = cache_kset(s);
5578 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5582 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5587 if (is_root_cache(s)) {
5588 s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5589 if (!s->memcg_kset) {
5596 kobject_uevent(&s->kobj, KOBJ_ADD);
5598 /* Setup first alias */
5599 sysfs_slab_alias(s, s->name);
5606 kobject_del(&s->kobj);
5610 void sysfs_slab_remove(struct kmem_cache *s)
5612 if (slab_state < FULL)
5614 * Sysfs has not been setup yet so no need to remove the
5620 kset_unregister(s->memcg_kset);
5622 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5623 kobject_del(&s->kobj);
5624 kobject_put(&s->kobj);
5628 * Need to buffer aliases during bootup until sysfs becomes
5629 * available lest we lose that information.
5631 struct saved_alias {
5632 struct kmem_cache *s;
5634 struct saved_alias *next;
5637 static struct saved_alias *alias_list;
5639 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5641 struct saved_alias *al;
5643 if (slab_state == FULL) {
5645 * If we have a leftover link then remove it.
5647 sysfs_remove_link(&slab_kset->kobj, name);
5648 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5651 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5657 al->next = alias_list;
5662 static int __init slab_sysfs_init(void)
5664 struct kmem_cache *s;
5667 mutex_lock(&slab_mutex);
5669 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5671 mutex_unlock(&slab_mutex);
5672 pr_err("Cannot register slab subsystem.\n");
5678 list_for_each_entry(s, &slab_caches, list) {
5679 err = sysfs_slab_add(s);
5681 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5685 while (alias_list) {
5686 struct saved_alias *al = alias_list;
5688 alias_list = alias_list->next;
5689 err = sysfs_slab_alias(al->s, al->name);
5691 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5696 mutex_unlock(&slab_mutex);
5701 __initcall(slab_sysfs_init);
5702 #endif /* CONFIG_SYSFS */
5705 * The /proc/slabinfo ABI
5707 #ifdef CONFIG_SLABINFO
5708 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5710 unsigned long nr_slabs = 0;
5711 unsigned long nr_objs = 0;
5712 unsigned long nr_free = 0;
5714 struct kmem_cache_node *n;
5716 for_each_kmem_cache_node(s, node, n) {
5717 nr_slabs += node_nr_slabs(n);
5718 nr_objs += node_nr_objs(n);
5719 nr_free += count_partial(n, count_free);
5722 sinfo->active_objs = nr_objs - nr_free;
5723 sinfo->num_objs = nr_objs;
5724 sinfo->active_slabs = nr_slabs;
5725 sinfo->num_slabs = nr_slabs;
5726 sinfo->objects_per_slab = oo_objects(s->oo);
5727 sinfo->cache_order = oo_order(s->oo);
5730 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5734 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5735 size_t count, loff_t *ppos)
5739 #endif /* CONFIG_SLABINFO */