1 // SPDX-License-Identifier: GPL-2.0
3 * SLUB: A slab allocator that limits cache line use instead of queuing
4 * objects in per cpu and per node lists.
6 * The allocator synchronizes using per slab locks or atomic operatios
7 * and only uses a centralized lock to manage a pool of partial slabs.
9 * (C) 2007 SGI, Christoph Lameter
10 * (C) 2011 Linux Foundation, Christoph Lameter
14 #include <linux/swap.h> /* struct reclaim_state */
15 #include <linux/module.h>
16 #include <linux/bit_spinlock.h>
17 #include <linux/interrupt.h>
18 #include <linux/bitops.h>
19 #include <linux/slab.h>
21 #include <linux/proc_fs.h>
22 #include <linux/notifier.h>
23 #include <linux/seq_file.h>
24 #include <linux/kasan.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>
37 #include <linux/random.h>
39 #include <trace/events/kmem.h>
45 * 1. slab_mutex (Global Mutex)
47 * 3. slab_lock(page) (Only on some arches and for debugging)
51 * The role of the slab_mutex is to protect the list of all the slabs
52 * and to synchronize major metadata changes to slab cache structures.
54 * The slab_lock is only used for debugging and on arches that do not
55 * have the ability to do a cmpxchg_double. It only protects the second
56 * double word in the page struct. Meaning
57 * A. page->freelist -> List of object free in a page
58 * B. page->counters -> Counters of objects
59 * C. page->frozen -> frozen state
61 * If a slab is frozen then it is exempt from list management. It is not
62 * on any list. The processor that froze the slab is the one who can
63 * perform list operations on the page. Other processors may put objects
64 * onto the freelist but the processor that froze the slab is the only
65 * one that can retrieve the objects from the page's freelist.
67 * The list_lock protects the partial and full list on each node and
68 * the partial slab counter. If taken then no new slabs may be added or
69 * removed from the lists nor make the number of partial slabs be modified.
70 * (Note that the total number of slabs is an atomic value that may be
71 * modified without taking the list lock).
73 * The list_lock is a centralized lock and thus we avoid taking it as
74 * much as possible. As long as SLUB does not have to handle partial
75 * slabs, operations can continue without any centralized lock. F.e.
76 * allocating a long series of objects that fill up slabs does not require
78 * Interrupts are disabled during allocation and deallocation in order to
79 * make the slab allocator safe to use in the context of an irq. In addition
80 * interrupts are disabled to ensure that the processor does not change
81 * while handling per_cpu slabs, due to kernel preemption.
83 * SLUB assigns one slab for allocation to each processor.
84 * Allocations only occur from these slabs called cpu slabs.
86 * Slabs with free elements are kept on a partial list and during regular
87 * operations no list for full slabs is used. If an object in a full slab is
88 * freed then the slab will show up again on the partial lists.
89 * We track full slabs for debugging purposes though because otherwise we
90 * cannot scan all objects.
92 * Slabs are freed when they become empty. Teardown and setup is
93 * minimal so we rely on the page allocators per cpu caches for
94 * fast frees and allocs.
96 * Overloading of page flags that are otherwise used for LRU management.
98 * PageActive The slab is frozen and exempt from list processing.
99 * This means that the slab is dedicated to a purpose
100 * such as satisfying allocations for a specific
101 * processor. Objects may be freed in the slab while
102 * it is frozen but slab_free will then skip the usual
103 * list operations. It is up to the processor holding
104 * the slab to integrate the slab into the slab lists
105 * when the slab is no longer needed.
107 * One use of this flag is to mark slabs that are
108 * used for allocations. Then such a slab becomes a cpu
109 * slab. The cpu slab may be equipped with an additional
110 * freelist that allows lockless access to
111 * free objects in addition to the regular freelist
112 * that requires the slab lock.
114 * PageError Slab requires special handling due to debug
115 * options set. This moves slab handling out of
116 * the fast path and disables lockless freelists.
119 static inline int kmem_cache_debug(struct kmem_cache *s)
121 #ifdef CONFIG_SLUB_DEBUG
122 return unlikely(s->flags & SLAB_DEBUG_FLAGS);
128 void *fixup_red_left(struct kmem_cache *s, void *p)
130 if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)
131 p += s->red_left_pad;
136 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
138 #ifdef CONFIG_SLUB_CPU_PARTIAL
139 return !kmem_cache_debug(s);
146 * Issues still to be resolved:
148 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
150 * - Variable sizing of the per node arrays
153 /* Enable to test recovery from slab corruption on boot */
154 #undef SLUB_RESILIENCY_TEST
156 /* Enable to log cmpxchg failures */
157 #undef SLUB_DEBUG_CMPXCHG
160 * Mininum number of partial slabs. These will be left on the partial
161 * lists even if they are empty. kmem_cache_shrink may reclaim them.
163 #define MIN_PARTIAL 5
166 * Maximum number of desirable partial slabs.
167 * The existence of more partial slabs makes kmem_cache_shrink
168 * sort the partial list by the number of objects in use.
170 #define MAX_PARTIAL 10
172 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
173 SLAB_POISON | SLAB_STORE_USER)
176 * These debug flags cannot use CMPXCHG because there might be consistency
177 * issues when checking or reading debug information
179 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
184 * Debugging flags that require metadata to be stored in the slab. These get
185 * disabled when slub_debug=O is used and a cache's min order increases with
188 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
191 #define OO_MASK ((1 << OO_SHIFT) - 1)
192 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
194 /* Internal SLUB flags */
196 #define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
197 /* Use cmpxchg_double */
198 #define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
201 * Tracking user of a slab.
203 #define TRACK_ADDRS_COUNT 16
205 unsigned long addr; /* Called from address */
206 #ifdef CONFIG_STACKTRACE
207 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
209 int cpu; /* Was running on cpu */
210 int pid; /* Pid context */
211 unsigned long when; /* When did the operation occur */
214 enum track_item { TRACK_ALLOC, TRACK_FREE };
217 static int sysfs_slab_add(struct kmem_cache *);
218 static int sysfs_slab_alias(struct kmem_cache *, const char *);
219 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
220 static void sysfs_slab_remove(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) { }
226 static inline void sysfs_slab_remove(struct kmem_cache *s) { }
229 static inline void stat(const struct kmem_cache *s, enum stat_item si)
231 #ifdef CONFIG_SLUB_STATS
233 * The rmw is racy on a preemptible kernel but this is acceptable, so
234 * avoid this_cpu_add()'s irq-disable overhead.
236 raw_cpu_inc(s->cpu_slab->stat[si]);
240 /********************************************************************
241 * Core slab cache functions
242 *******************************************************************/
245 * Returns freelist pointer (ptr). With hardening, this is obfuscated
246 * with an XOR of the address where the pointer is held and a per-cache
249 static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
250 unsigned long ptr_addr)
252 #ifdef CONFIG_SLAB_FREELIST_HARDENED
253 return (void *)((unsigned long)ptr ^ s->random ^ ptr_addr);
259 /* Returns the freelist pointer recorded at location ptr_addr. */
260 static inline void *freelist_dereference(const struct kmem_cache *s,
263 return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
264 (unsigned long)ptr_addr);
267 static inline void *get_freepointer(struct kmem_cache *s, void *object)
269 return freelist_dereference(s, object + s->offset);
272 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
275 prefetch(freelist_dereference(s, object + s->offset));
278 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
280 unsigned long freepointer_addr;
283 if (!debug_pagealloc_enabled())
284 return get_freepointer(s, object);
286 freepointer_addr = (unsigned long)object + s->offset;
287 probe_kernel_read(&p, (void **)freepointer_addr, sizeof(p));
288 return freelist_ptr(s, p, freepointer_addr);
291 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
293 unsigned long freeptr_addr = (unsigned long)object + s->offset;
295 #ifdef CONFIG_SLAB_FREELIST_HARDENED
296 BUG_ON(object == fp); /* naive detection of double free or corruption */
299 *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
302 /* Loop over all objects in a slab */
303 #define for_each_object(__p, __s, __addr, __objects) \
304 for (__p = fixup_red_left(__s, __addr); \
305 __p < (__addr) + (__objects) * (__s)->size; \
308 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
309 for (__p = fixup_red_left(__s, __addr), __idx = 1; \
310 __idx <= __objects; \
311 __p += (__s)->size, __idx++)
313 /* Determine object index from a given position */
314 static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr)
316 return (p - addr) / s->size;
319 static inline int order_objects(int order, unsigned long size, int reserved)
321 return ((PAGE_SIZE << order) - reserved) / size;
324 static inline struct kmem_cache_order_objects oo_make(int order,
325 unsigned long size, int reserved)
327 struct kmem_cache_order_objects x = {
328 (order << OO_SHIFT) + order_objects(order, size, reserved)
334 static inline int oo_order(struct kmem_cache_order_objects x)
336 return x.x >> OO_SHIFT;
339 static inline int oo_objects(struct kmem_cache_order_objects x)
341 return x.x & OO_MASK;
345 * Per slab locking using the pagelock
347 static __always_inline void slab_lock(struct page *page)
349 VM_BUG_ON_PAGE(PageTail(page), page);
350 bit_spin_lock(PG_locked, &page->flags);
353 static __always_inline void slab_unlock(struct page *page)
355 VM_BUG_ON_PAGE(PageTail(page), page);
356 __bit_spin_unlock(PG_locked, &page->flags);
359 static inline void set_page_slub_counters(struct page *page, unsigned long counters_new)
362 tmp.counters = counters_new;
364 * page->counters can cover frozen/inuse/objects as well
365 * as page->_refcount. If we assign to ->counters directly
366 * we run the risk of losing updates to page->_refcount, so
367 * be careful and only assign to the fields we need.
369 page->frozen = tmp.frozen;
370 page->inuse = tmp.inuse;
371 page->objects = tmp.objects;
374 /* Interrupts must be disabled (for the fallback code to work right) */
375 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
376 void *freelist_old, unsigned long counters_old,
377 void *freelist_new, unsigned long counters_new,
380 VM_BUG_ON(!irqs_disabled());
381 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
382 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
383 if (s->flags & __CMPXCHG_DOUBLE) {
384 if (cmpxchg_double(&page->freelist, &page->counters,
385 freelist_old, counters_old,
386 freelist_new, counters_new))
392 if (page->freelist == freelist_old &&
393 page->counters == counters_old) {
394 page->freelist = freelist_new;
395 set_page_slub_counters(page, counters_new);
403 stat(s, CMPXCHG_DOUBLE_FAIL);
405 #ifdef SLUB_DEBUG_CMPXCHG
406 pr_info("%s %s: cmpxchg double redo ", n, s->name);
412 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
413 void *freelist_old, unsigned long counters_old,
414 void *freelist_new, unsigned long counters_new,
417 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
418 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
419 if (s->flags & __CMPXCHG_DOUBLE) {
420 if (cmpxchg_double(&page->freelist, &page->counters,
421 freelist_old, counters_old,
422 freelist_new, counters_new))
429 local_irq_save(flags);
431 if (page->freelist == freelist_old &&
432 page->counters == counters_old) {
433 page->freelist = freelist_new;
434 set_page_slub_counters(page, counters_new);
436 local_irq_restore(flags);
440 local_irq_restore(flags);
444 stat(s, CMPXCHG_DOUBLE_FAIL);
446 #ifdef SLUB_DEBUG_CMPXCHG
447 pr_info("%s %s: cmpxchg double redo ", n, s->name);
453 #ifdef CONFIG_SLUB_DEBUG
455 * Determine a map of object in use on a page.
457 * Node listlock must be held to guarantee that the page does
458 * not vanish from under us.
460 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
463 void *addr = page_address(page);
465 for (p = page->freelist; p; p = get_freepointer(s, p))
466 set_bit(slab_index(p, s, addr), map);
469 static inline int size_from_object(struct kmem_cache *s)
471 if (s->flags & SLAB_RED_ZONE)
472 return s->size - s->red_left_pad;
477 static inline void *restore_red_left(struct kmem_cache *s, void *p)
479 if (s->flags & SLAB_RED_ZONE)
480 p -= s->red_left_pad;
488 #if defined(CONFIG_SLUB_DEBUG_ON)
489 static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
491 static slab_flags_t slub_debug;
494 static char *slub_debug_slabs;
495 static int disable_higher_order_debug;
498 * slub is about to manipulate internal object metadata. This memory lies
499 * outside the range of the allocated object, so accessing it would normally
500 * be reported by kasan as a bounds error. metadata_access_enable() is used
501 * to tell kasan that these accesses are OK.
503 static inline void metadata_access_enable(void)
505 kasan_disable_current();
508 static inline void metadata_access_disable(void)
510 kasan_enable_current();
517 /* Verify that a pointer has an address that is valid within a slab page */
518 static inline int check_valid_pointer(struct kmem_cache *s,
519 struct page *page, void *object)
526 base = page_address(page);
527 object = restore_red_left(s, object);
528 if (object < base || object >= base + page->objects * s->size ||
529 (object - base) % s->size) {
536 static void print_section(char *level, char *text, u8 *addr,
539 metadata_access_enable();
540 print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
542 metadata_access_disable();
545 static struct track *get_track(struct kmem_cache *s, void *object,
546 enum track_item alloc)
551 p = object + s->offset + sizeof(void *);
553 p = object + s->inuse;
558 static void set_track(struct kmem_cache *s, void *object,
559 enum track_item alloc, unsigned long addr)
561 struct track *p = get_track(s, object, alloc);
564 #ifdef CONFIG_STACKTRACE
565 struct stack_trace trace;
568 trace.nr_entries = 0;
569 trace.max_entries = TRACK_ADDRS_COUNT;
570 trace.entries = p->addrs;
572 metadata_access_enable();
573 save_stack_trace(&trace);
574 metadata_access_disable();
576 /* See rant in lockdep.c */
577 if (trace.nr_entries != 0 &&
578 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
581 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
585 p->cpu = smp_processor_id();
586 p->pid = current->pid;
589 memset(p, 0, sizeof(struct track));
592 static void init_tracking(struct kmem_cache *s, void *object)
594 if (!(s->flags & SLAB_STORE_USER))
597 set_track(s, object, TRACK_FREE, 0UL);
598 set_track(s, object, TRACK_ALLOC, 0UL);
601 static void print_track(const char *s, struct track *t, unsigned long pr_time)
606 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
607 s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
608 #ifdef CONFIG_STACKTRACE
611 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
613 pr_err("\t%pS\n", (void *)t->addrs[i]);
620 static void print_tracking(struct kmem_cache *s, void *object)
622 unsigned long pr_time = jiffies;
623 if (!(s->flags & SLAB_STORE_USER))
626 print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
627 print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
630 static void print_page_info(struct page *page)
632 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
633 page, page->objects, page->inuse, page->freelist, page->flags);
637 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
639 struct va_format vaf;
645 pr_err("=============================================================================\n");
646 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
647 pr_err("-----------------------------------------------------------------------------\n\n");
649 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
653 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
655 struct va_format vaf;
661 pr_err("FIX %s: %pV\n", s->name, &vaf);
665 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
667 unsigned int off; /* Offset of last byte */
668 u8 *addr = page_address(page);
670 print_tracking(s, p);
672 print_page_info(page);
674 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
675 p, p - addr, get_freepointer(s, p));
677 if (s->flags & SLAB_RED_ZONE)
678 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
680 else if (p > addr + 16)
681 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
683 print_section(KERN_ERR, "Object ", p,
684 min_t(unsigned int, s->object_size, PAGE_SIZE));
685 if (s->flags & SLAB_RED_ZONE)
686 print_section(KERN_ERR, "Redzone ", p + s->object_size,
687 s->inuse - s->object_size);
690 off = s->offset + sizeof(void *);
694 if (s->flags & SLAB_STORE_USER)
695 off += 2 * sizeof(struct track);
697 off += kasan_metadata_size(s);
699 if (off != size_from_object(s))
700 /* Beginning of the filler is the free pointer */
701 print_section(KERN_ERR, "Padding ", p + off,
702 size_from_object(s) - off);
707 void object_err(struct kmem_cache *s, struct page *page,
708 u8 *object, char *reason)
710 slab_bug(s, "%s", reason);
711 print_trailer(s, page, object);
714 static void slab_err(struct kmem_cache *s, struct page *page,
715 const char *fmt, ...)
721 vsnprintf(buf, sizeof(buf), fmt, args);
723 slab_bug(s, "%s", buf);
724 print_page_info(page);
728 static void init_object(struct kmem_cache *s, void *object, u8 val)
732 if (s->flags & SLAB_RED_ZONE)
733 memset(p - s->red_left_pad, val, s->red_left_pad);
735 if (s->flags & __OBJECT_POISON) {
736 memset(p, POISON_FREE, s->object_size - 1);
737 p[s->object_size - 1] = POISON_END;
740 if (s->flags & SLAB_RED_ZONE)
741 memset(p + s->object_size, val, s->inuse - s->object_size);
744 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
745 void *from, void *to)
747 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
748 memset(from, data, to - from);
751 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
752 u8 *object, char *what,
753 u8 *start, unsigned int value, unsigned int bytes)
758 metadata_access_enable();
759 fault = memchr_inv(start, value, bytes);
760 metadata_access_disable();
765 while (end > fault && end[-1] == value)
768 slab_bug(s, "%s overwritten", what);
769 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
770 fault, end - 1, fault[0], value);
771 print_trailer(s, page, object);
773 restore_bytes(s, what, value, fault, end);
781 * Bytes of the object to be managed.
782 * If the freepointer may overlay the object then the free
783 * pointer is the first word of the object.
785 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
788 * object + s->object_size
789 * Padding to reach word boundary. This is also used for Redzoning.
790 * Padding is extended by another word if Redzoning is enabled and
791 * object_size == inuse.
793 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
794 * 0xcc (RED_ACTIVE) for objects in use.
797 * Meta data starts here.
799 * A. Free pointer (if we cannot overwrite object on free)
800 * B. Tracking data for SLAB_STORE_USER
801 * C. Padding to reach required alignment boundary or at mininum
802 * one word if debugging is on to be able to detect writes
803 * before the word boundary.
805 * Padding is done using 0x5a (POISON_INUSE)
808 * Nothing is used beyond s->size.
810 * If slabcaches are merged then the object_size and inuse boundaries are mostly
811 * ignored. And therefore no slab options that rely on these boundaries
812 * may be used with merged slabcaches.
815 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
817 unsigned long off = s->inuse; /* The end of info */
820 /* Freepointer is placed after the object. */
821 off += sizeof(void *);
823 if (s->flags & SLAB_STORE_USER)
824 /* We also have user information there */
825 off += 2 * sizeof(struct track);
827 off += kasan_metadata_size(s);
829 if (size_from_object(s) == off)
832 return check_bytes_and_report(s, page, p, "Object padding",
833 p + off, POISON_INUSE, size_from_object(s) - off);
836 /* Check the pad bytes at the end of a slab page */
837 static int slab_pad_check(struct kmem_cache *s, struct page *page)
846 if (!(s->flags & SLAB_POISON))
849 start = page_address(page);
850 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
851 end = start + length;
852 remainder = length % s->size;
856 pad = end - remainder;
857 metadata_access_enable();
858 fault = memchr_inv(pad, POISON_INUSE, remainder);
859 metadata_access_disable();
862 while (end > fault && end[-1] == POISON_INUSE)
865 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
866 print_section(KERN_ERR, "Padding ", pad, remainder);
868 restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
872 static int check_object(struct kmem_cache *s, struct page *page,
873 void *object, u8 val)
876 u8 *endobject = object + s->object_size;
878 if (s->flags & SLAB_RED_ZONE) {
879 if (!check_bytes_and_report(s, page, object, "Redzone",
880 object - s->red_left_pad, val, s->red_left_pad))
883 if (!check_bytes_and_report(s, page, object, "Redzone",
884 endobject, val, s->inuse - s->object_size))
887 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
888 check_bytes_and_report(s, page, p, "Alignment padding",
889 endobject, POISON_INUSE,
890 s->inuse - s->object_size);
894 if (s->flags & SLAB_POISON) {
895 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
896 (!check_bytes_and_report(s, page, p, "Poison", p,
897 POISON_FREE, s->object_size - 1) ||
898 !check_bytes_and_report(s, page, p, "Poison",
899 p + s->object_size - 1, POISON_END, 1)))
902 * check_pad_bytes cleans up on its own.
904 check_pad_bytes(s, page, p);
907 if (!s->offset && val == SLUB_RED_ACTIVE)
909 * Object and freepointer overlap. Cannot check
910 * freepointer while object is allocated.
914 /* Check free pointer validity */
915 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
916 object_err(s, page, p, "Freepointer corrupt");
918 * No choice but to zap it and thus lose the remainder
919 * of the free objects in this slab. May cause
920 * another error because the object count is now wrong.
922 set_freepointer(s, p, NULL);
928 static int check_slab(struct kmem_cache *s, struct page *page)
932 VM_BUG_ON(!irqs_disabled());
934 if (!PageSlab(page)) {
935 slab_err(s, page, "Not a valid slab page");
939 maxobj = order_objects(compound_order(page), s->size, s->reserved);
940 if (page->objects > maxobj) {
941 slab_err(s, page, "objects %u > max %u",
942 page->objects, maxobj);
945 if (page->inuse > page->objects) {
946 slab_err(s, page, "inuse %u > max %u",
947 page->inuse, page->objects);
950 /* Slab_pad_check fixes things up after itself */
951 slab_pad_check(s, page);
956 * Determine if a certain object on a page is on the freelist. Must hold the
957 * slab lock to guarantee that the chains are in a consistent state.
959 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
967 while (fp && nr <= page->objects) {
970 if (!check_valid_pointer(s, page, fp)) {
972 object_err(s, page, object,
973 "Freechain corrupt");
974 set_freepointer(s, object, NULL);
976 slab_err(s, page, "Freepointer corrupt");
977 page->freelist = NULL;
978 page->inuse = page->objects;
979 slab_fix(s, "Freelist cleared");
985 fp = get_freepointer(s, object);
989 max_objects = order_objects(compound_order(page), s->size, s->reserved);
990 if (max_objects > MAX_OBJS_PER_PAGE)
991 max_objects = MAX_OBJS_PER_PAGE;
993 if (page->objects != max_objects) {
994 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
995 page->objects, max_objects);
996 page->objects = max_objects;
997 slab_fix(s, "Number of objects adjusted.");
999 if (page->inuse != page->objects - nr) {
1000 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
1001 page->inuse, page->objects - nr);
1002 page->inuse = page->objects - nr;
1003 slab_fix(s, "Object count adjusted.");
1005 return search == NULL;
1008 static void trace(struct kmem_cache *s, struct page *page, void *object,
1011 if (s->flags & SLAB_TRACE) {
1012 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1014 alloc ? "alloc" : "free",
1015 object, page->inuse,
1019 print_section(KERN_INFO, "Object ", (void *)object,
1027 * Tracking of fully allocated slabs for debugging purposes.
1029 static void add_full(struct kmem_cache *s,
1030 struct kmem_cache_node *n, struct page *page)
1032 if (!(s->flags & SLAB_STORE_USER))
1035 lockdep_assert_held(&n->list_lock);
1036 list_add(&page->lru, &n->full);
1039 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1041 if (!(s->flags & SLAB_STORE_USER))
1044 lockdep_assert_held(&n->list_lock);
1045 list_del(&page->lru);
1048 /* Tracking of the number of slabs for debugging purposes */
1049 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1051 struct kmem_cache_node *n = get_node(s, node);
1053 return atomic_long_read(&n->nr_slabs);
1056 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1058 return atomic_long_read(&n->nr_slabs);
1061 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1063 struct kmem_cache_node *n = get_node(s, node);
1066 * May be called early in order to allocate a slab for the
1067 * kmem_cache_node structure. Solve the chicken-egg
1068 * dilemma by deferring the increment of the count during
1069 * bootstrap (see early_kmem_cache_node_alloc).
1072 atomic_long_inc(&n->nr_slabs);
1073 atomic_long_add(objects, &n->total_objects);
1076 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1078 struct kmem_cache_node *n = get_node(s, node);
1080 atomic_long_dec(&n->nr_slabs);
1081 atomic_long_sub(objects, &n->total_objects);
1084 /* Object debug checks for alloc/free paths */
1085 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1088 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1091 init_object(s, object, SLUB_RED_INACTIVE);
1092 init_tracking(s, object);
1095 static inline int alloc_consistency_checks(struct kmem_cache *s,
1097 void *object, unsigned long addr)
1099 if (!check_slab(s, page))
1102 if (!check_valid_pointer(s, page, object)) {
1103 object_err(s, page, object, "Freelist Pointer check fails");
1107 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1113 static noinline int alloc_debug_processing(struct kmem_cache *s,
1115 void *object, unsigned long addr)
1117 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1118 if (!alloc_consistency_checks(s, page, object, addr))
1122 /* Success perform special debug activities for allocs */
1123 if (s->flags & SLAB_STORE_USER)
1124 set_track(s, object, TRACK_ALLOC, addr);
1125 trace(s, page, object, 1);
1126 init_object(s, object, SLUB_RED_ACTIVE);
1130 if (PageSlab(page)) {
1132 * If this is a slab page then lets do the best we can
1133 * to avoid issues in the future. Marking all objects
1134 * as used avoids touching the remaining objects.
1136 slab_fix(s, "Marking all objects used");
1137 page->inuse = page->objects;
1138 page->freelist = NULL;
1143 static inline int free_consistency_checks(struct kmem_cache *s,
1144 struct page *page, void *object, unsigned long addr)
1146 if (!check_valid_pointer(s, page, object)) {
1147 slab_err(s, page, "Invalid object pointer 0x%p", object);
1151 if (on_freelist(s, page, object)) {
1152 object_err(s, page, object, "Object already free");
1156 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1159 if (unlikely(s != page->slab_cache)) {
1160 if (!PageSlab(page)) {
1161 slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1163 } else if (!page->slab_cache) {
1164 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1168 object_err(s, page, object,
1169 "page slab pointer corrupt.");
1175 /* Supports checking bulk free of a constructed freelist */
1176 static noinline int free_debug_processing(
1177 struct kmem_cache *s, struct page *page,
1178 void *head, void *tail, int bulk_cnt,
1181 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1182 void *object = head;
1184 unsigned long uninitialized_var(flags);
1187 spin_lock_irqsave(&n->list_lock, flags);
1190 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1191 if (!check_slab(s, page))
1198 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1199 if (!free_consistency_checks(s, page, object, addr))
1203 if (s->flags & SLAB_STORE_USER)
1204 set_track(s, object, TRACK_FREE, addr);
1205 trace(s, page, object, 0);
1206 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1207 init_object(s, object, SLUB_RED_INACTIVE);
1209 /* Reached end of constructed freelist yet? */
1210 if (object != tail) {
1211 object = get_freepointer(s, object);
1217 if (cnt != bulk_cnt)
1218 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1222 spin_unlock_irqrestore(&n->list_lock, flags);
1224 slab_fix(s, "Object at 0x%p not freed", object);
1228 static int __init setup_slub_debug(char *str)
1230 slub_debug = DEBUG_DEFAULT_FLAGS;
1231 if (*str++ != '=' || !*str)
1233 * No options specified. Switch on full debugging.
1239 * No options but restriction on slabs. This means full
1240 * debugging for slabs matching a pattern.
1247 * Switch off all debugging measures.
1252 * Determine which debug features should be switched on
1254 for (; *str && *str != ','; str++) {
1255 switch (tolower(*str)) {
1257 slub_debug |= SLAB_CONSISTENCY_CHECKS;
1260 slub_debug |= SLAB_RED_ZONE;
1263 slub_debug |= SLAB_POISON;
1266 slub_debug |= SLAB_STORE_USER;
1269 slub_debug |= SLAB_TRACE;
1272 slub_debug |= SLAB_FAILSLAB;
1276 * Avoid enabling debugging on caches if its minimum
1277 * order would increase as a result.
1279 disable_higher_order_debug = 1;
1282 pr_err("slub_debug option '%c' unknown. skipped\n",
1289 slub_debug_slabs = str + 1;
1294 __setup("slub_debug", setup_slub_debug);
1296 slab_flags_t kmem_cache_flags(unsigned int object_size,
1297 slab_flags_t flags, const char *name,
1298 void (*ctor)(void *))
1301 * Enable debugging if selected on the kernel commandline.
1303 if (slub_debug && (!slub_debug_slabs || (name &&
1304 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))))
1305 flags |= slub_debug;
1309 #else /* !CONFIG_SLUB_DEBUG */
1310 static inline void setup_object_debug(struct kmem_cache *s,
1311 struct page *page, void *object) {}
1313 static inline int alloc_debug_processing(struct kmem_cache *s,
1314 struct page *page, void *object, unsigned long addr) { return 0; }
1316 static inline int free_debug_processing(
1317 struct kmem_cache *s, struct page *page,
1318 void *head, void *tail, int bulk_cnt,
1319 unsigned long addr) { return 0; }
1321 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1323 static inline int check_object(struct kmem_cache *s, struct page *page,
1324 void *object, u8 val) { return 1; }
1325 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1326 struct page *page) {}
1327 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1328 struct page *page) {}
1329 slab_flags_t kmem_cache_flags(unsigned int object_size,
1330 slab_flags_t flags, const char *name,
1331 void (*ctor)(void *))
1335 #define slub_debug 0
1337 #define disable_higher_order_debug 0
1339 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1341 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1343 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1345 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1348 #endif /* CONFIG_SLUB_DEBUG */
1351 * Hooks for other subsystems that check memory allocations. In a typical
1352 * production configuration these hooks all should produce no code at all.
1354 static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1356 kmemleak_alloc(ptr, size, 1, flags);
1357 kasan_kmalloc_large(ptr, size, flags);
1360 static __always_inline void kfree_hook(void *x)
1363 kasan_kfree_large(x, _RET_IP_);
1366 static __always_inline void *slab_free_hook(struct kmem_cache *s, void *x)
1370 kmemleak_free_recursive(x, s->flags);
1373 * Trouble is that we may no longer disable interrupts in the fast path
1374 * So in order to make the debug calls that expect irqs to be
1375 * disabled we need to disable interrupts temporarily.
1377 #ifdef CONFIG_LOCKDEP
1379 unsigned long flags;
1381 local_irq_save(flags);
1382 debug_check_no_locks_freed(x, s->object_size);
1383 local_irq_restore(flags);
1386 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1387 debug_check_no_obj_freed(x, s->object_size);
1389 freeptr = get_freepointer(s, x);
1391 * kasan_slab_free() may put x into memory quarantine, delaying its
1392 * reuse. In this case the object's freelist pointer is changed.
1394 kasan_slab_free(s, x, _RET_IP_);
1398 static inline void slab_free_freelist_hook(struct kmem_cache *s,
1399 void *head, void *tail)
1402 * Compiler cannot detect this function can be removed if slab_free_hook()
1403 * evaluates to nothing. Thus, catch all relevant config debug options here.
1405 #if defined(CONFIG_LOCKDEP) || \
1406 defined(CONFIG_DEBUG_KMEMLEAK) || \
1407 defined(CONFIG_DEBUG_OBJECTS_FREE) || \
1408 defined(CONFIG_KASAN)
1410 void *object = head;
1411 void *tail_obj = tail ? : head;
1415 freeptr = slab_free_hook(s, object);
1416 } while ((object != tail_obj) && (object = freeptr));
1420 static void setup_object(struct kmem_cache *s, struct page *page,
1423 setup_object_debug(s, page, object);
1424 kasan_init_slab_obj(s, object);
1425 if (unlikely(s->ctor)) {
1426 kasan_unpoison_object_data(s, object);
1428 kasan_poison_object_data(s, object);
1433 * Slab allocation and freeing
1435 static inline struct page *alloc_slab_page(struct kmem_cache *s,
1436 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1439 int order = oo_order(oo);
1441 if (node == NUMA_NO_NODE)
1442 page = alloc_pages(flags, order);
1444 page = __alloc_pages_node(node, flags, order);
1446 if (page && memcg_charge_slab(page, flags, order, s)) {
1447 __free_pages(page, order);
1454 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1455 /* Pre-initialize the random sequence cache */
1456 static int init_cache_random_seq(struct kmem_cache *s)
1459 unsigned long i, count = oo_objects(s->oo);
1461 /* Bailout if already initialised */
1465 err = cache_random_seq_create(s, count, GFP_KERNEL);
1467 pr_err("SLUB: Unable to initialize free list for %s\n",
1472 /* Transform to an offset on the set of pages */
1473 if (s->random_seq) {
1474 for (i = 0; i < count; i++)
1475 s->random_seq[i] *= s->size;
1480 /* Initialize each random sequence freelist per cache */
1481 static void __init init_freelist_randomization(void)
1483 struct kmem_cache *s;
1485 mutex_lock(&slab_mutex);
1487 list_for_each_entry(s, &slab_caches, list)
1488 init_cache_random_seq(s);
1490 mutex_unlock(&slab_mutex);
1493 /* Get the next entry on the pre-computed freelist randomized */
1494 static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1495 unsigned long *pos, void *start,
1496 unsigned long page_limit,
1497 unsigned long freelist_count)
1502 * If the target page allocation failed, the number of objects on the
1503 * page might be smaller than the usual size defined by the cache.
1506 idx = s->random_seq[*pos];
1508 if (*pos >= freelist_count)
1510 } while (unlikely(idx >= page_limit));
1512 return (char *)start + idx;
1515 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1516 static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1521 unsigned long idx, pos, page_limit, freelist_count;
1523 if (page->objects < 2 || !s->random_seq)
1526 freelist_count = oo_objects(s->oo);
1527 pos = get_random_int() % freelist_count;
1529 page_limit = page->objects * s->size;
1530 start = fixup_red_left(s, page_address(page));
1532 /* First entry is used as the base of the freelist */
1533 cur = next_freelist_entry(s, page, &pos, start, page_limit,
1535 page->freelist = cur;
1537 for (idx = 1; idx < page->objects; idx++) {
1538 setup_object(s, page, cur);
1539 next = next_freelist_entry(s, page, &pos, start, page_limit,
1541 set_freepointer(s, cur, next);
1544 setup_object(s, page, cur);
1545 set_freepointer(s, cur, NULL);
1550 static inline int init_cache_random_seq(struct kmem_cache *s)
1554 static inline void init_freelist_randomization(void) { }
1555 static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1559 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1561 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1564 struct kmem_cache_order_objects oo = s->oo;
1570 flags &= gfp_allowed_mask;
1572 if (gfpflags_allow_blocking(flags))
1575 flags |= s->allocflags;
1578 * Let the initial higher-order allocation fail under memory pressure
1579 * so we fall-back to the minimum order allocation.
1581 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1582 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1583 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1585 page = alloc_slab_page(s, alloc_gfp, node, oo);
1586 if (unlikely(!page)) {
1590 * Allocation may have failed due to fragmentation.
1591 * Try a lower order alloc if possible
1593 page = alloc_slab_page(s, alloc_gfp, node, oo);
1594 if (unlikely(!page))
1596 stat(s, ORDER_FALLBACK);
1599 page->objects = oo_objects(oo);
1601 order = compound_order(page);
1602 page->slab_cache = s;
1603 __SetPageSlab(page);
1604 if (page_is_pfmemalloc(page))
1605 SetPageSlabPfmemalloc(page);
1607 start = page_address(page);
1609 if (unlikely(s->flags & SLAB_POISON))
1610 memset(start, POISON_INUSE, PAGE_SIZE << order);
1612 kasan_poison_slab(page);
1614 shuffle = shuffle_freelist(s, page);
1617 for_each_object_idx(p, idx, s, start, page->objects) {
1618 setup_object(s, page, p);
1619 if (likely(idx < page->objects))
1620 set_freepointer(s, p, p + s->size);
1622 set_freepointer(s, p, NULL);
1624 page->freelist = fixup_red_left(s, start);
1627 page->inuse = page->objects;
1631 if (gfpflags_allow_blocking(flags))
1632 local_irq_disable();
1636 mod_lruvec_page_state(page,
1637 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1638 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1641 inc_slabs_node(s, page_to_nid(page), page->objects);
1646 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1648 if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1649 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1650 flags &= ~GFP_SLAB_BUG_MASK;
1651 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1652 invalid_mask, &invalid_mask, flags, &flags);
1656 return allocate_slab(s,
1657 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1660 static void __free_slab(struct kmem_cache *s, struct page *page)
1662 int order = compound_order(page);
1663 int pages = 1 << order;
1665 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1668 slab_pad_check(s, page);
1669 for_each_object(p, s, page_address(page),
1671 check_object(s, page, p, SLUB_RED_INACTIVE);
1674 mod_lruvec_page_state(page,
1675 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1676 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1679 __ClearPageSlabPfmemalloc(page);
1680 __ClearPageSlab(page);
1682 page_mapcount_reset(page);
1683 if (current->reclaim_state)
1684 current->reclaim_state->reclaimed_slab += pages;
1685 memcg_uncharge_slab(page, order, s);
1686 __free_pages(page, order);
1689 #define need_reserve_slab_rcu \
1690 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1692 static void rcu_free_slab(struct rcu_head *h)
1696 if (need_reserve_slab_rcu)
1697 page = virt_to_head_page(h);
1699 page = container_of((struct list_head *)h, struct page, lru);
1701 __free_slab(page->slab_cache, page);
1704 static void free_slab(struct kmem_cache *s, struct page *page)
1706 if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
1707 struct rcu_head *head;
1709 if (need_reserve_slab_rcu) {
1710 int order = compound_order(page);
1711 int offset = (PAGE_SIZE << order) - s->reserved;
1713 VM_BUG_ON(s->reserved != sizeof(*head));
1714 head = page_address(page) + offset;
1716 head = &page->rcu_head;
1719 call_rcu(head, rcu_free_slab);
1721 __free_slab(s, page);
1724 static void discard_slab(struct kmem_cache *s, struct page *page)
1726 dec_slabs_node(s, page_to_nid(page), page->objects);
1731 * Management of partially allocated slabs.
1734 __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1737 if (tail == DEACTIVATE_TO_TAIL)
1738 list_add_tail(&page->lru, &n->partial);
1740 list_add(&page->lru, &n->partial);
1743 static inline void add_partial(struct kmem_cache_node *n,
1744 struct page *page, int tail)
1746 lockdep_assert_held(&n->list_lock);
1747 __add_partial(n, page, tail);
1750 static inline void remove_partial(struct kmem_cache_node *n,
1753 lockdep_assert_held(&n->list_lock);
1754 list_del(&page->lru);
1759 * Remove slab from the partial list, freeze it and
1760 * return the pointer to the freelist.
1762 * Returns a list of objects or NULL if it fails.
1764 static inline void *acquire_slab(struct kmem_cache *s,
1765 struct kmem_cache_node *n, struct page *page,
1766 int mode, int *objects)
1769 unsigned long counters;
1772 lockdep_assert_held(&n->list_lock);
1775 * Zap the freelist and set the frozen bit.
1776 * The old freelist is the list of objects for the
1777 * per cpu allocation list.
1779 freelist = page->freelist;
1780 counters = page->counters;
1781 new.counters = counters;
1782 *objects = new.objects - new.inuse;
1784 new.inuse = page->objects;
1785 new.freelist = NULL;
1787 new.freelist = freelist;
1790 VM_BUG_ON(new.frozen);
1793 if (!__cmpxchg_double_slab(s, page,
1795 new.freelist, new.counters,
1799 remove_partial(n, page);
1804 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1805 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1808 * Try to allocate a partial slab from a specific node.
1810 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1811 struct kmem_cache_cpu *c, gfp_t flags)
1813 struct page *page, *page2;
1814 void *object = NULL;
1815 unsigned int available = 0;
1819 * Racy check. If we mistakenly see no partial slabs then we
1820 * just allocate an empty slab. If we mistakenly try to get a
1821 * partial slab and there is none available then get_partials()
1824 if (!n || !n->nr_partial)
1827 spin_lock(&n->list_lock);
1828 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1831 if (!pfmemalloc_match(page, flags))
1834 t = acquire_slab(s, n, page, object == NULL, &objects);
1838 available += objects;
1841 stat(s, ALLOC_FROM_PARTIAL);
1844 put_cpu_partial(s, page, 0);
1845 stat(s, CPU_PARTIAL_NODE);
1847 if (!kmem_cache_has_cpu_partial(s)
1848 || available > slub_cpu_partial(s) / 2)
1852 spin_unlock(&n->list_lock);
1857 * Get a page from somewhere. Search in increasing NUMA distances.
1859 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1860 struct kmem_cache_cpu *c)
1863 struct zonelist *zonelist;
1866 enum zone_type high_zoneidx = gfp_zone(flags);
1868 unsigned int cpuset_mems_cookie;
1871 * The defrag ratio allows a configuration of the tradeoffs between
1872 * inter node defragmentation and node local allocations. A lower
1873 * defrag_ratio increases the tendency to do local allocations
1874 * instead of attempting to obtain partial slabs from other nodes.
1876 * If the defrag_ratio is set to 0 then kmalloc() always
1877 * returns node local objects. If the ratio is higher then kmalloc()
1878 * may return off node objects because partial slabs are obtained
1879 * from other nodes and filled up.
1881 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
1882 * (which makes defrag_ratio = 1000) then every (well almost)
1883 * allocation will first attempt to defrag slab caches on other nodes.
1884 * This means scanning over all nodes to look for partial slabs which
1885 * may be expensive if we do it every time we are trying to find a slab
1886 * with available objects.
1888 if (!s->remote_node_defrag_ratio ||
1889 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1893 cpuset_mems_cookie = read_mems_allowed_begin();
1894 zonelist = node_zonelist(mempolicy_slab_node(), flags);
1895 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1896 struct kmem_cache_node *n;
1898 n = get_node(s, zone_to_nid(zone));
1900 if (n && cpuset_zone_allowed(zone, flags) &&
1901 n->nr_partial > s->min_partial) {
1902 object = get_partial_node(s, n, c, flags);
1905 * Don't check read_mems_allowed_retry()
1906 * here - if mems_allowed was updated in
1907 * parallel, that was a harmless race
1908 * between allocation and the cpuset
1915 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1921 * Get a partial page, lock it and return it.
1923 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1924 struct kmem_cache_cpu *c)
1927 int searchnode = node;
1929 if (node == NUMA_NO_NODE)
1930 searchnode = numa_mem_id();
1931 else if (!node_present_pages(node))
1932 searchnode = node_to_mem_node(node);
1934 object = get_partial_node(s, get_node(s, searchnode), c, flags);
1935 if (object || node != NUMA_NO_NODE)
1938 return get_any_partial(s, flags, c);
1941 #ifdef CONFIG_PREEMPT
1943 * Calculate the next globally unique transaction for disambiguiation
1944 * during cmpxchg. The transactions start with the cpu number and are then
1945 * incremented by CONFIG_NR_CPUS.
1947 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1950 * No preemption supported therefore also no need to check for
1956 static inline unsigned long next_tid(unsigned long tid)
1958 return tid + TID_STEP;
1961 static inline unsigned int tid_to_cpu(unsigned long tid)
1963 return tid % TID_STEP;
1966 static inline unsigned long tid_to_event(unsigned long tid)
1968 return tid / TID_STEP;
1971 static inline unsigned int init_tid(int cpu)
1976 static inline void note_cmpxchg_failure(const char *n,
1977 const struct kmem_cache *s, unsigned long tid)
1979 #ifdef SLUB_DEBUG_CMPXCHG
1980 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1982 pr_info("%s %s: cmpxchg redo ", n, s->name);
1984 #ifdef CONFIG_PREEMPT
1985 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1986 pr_warn("due to cpu change %d -> %d\n",
1987 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1990 if (tid_to_event(tid) != tid_to_event(actual_tid))
1991 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1992 tid_to_event(tid), tid_to_event(actual_tid));
1994 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1995 actual_tid, tid, next_tid(tid));
1997 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2000 static void init_kmem_cache_cpus(struct kmem_cache *s)
2004 for_each_possible_cpu(cpu)
2005 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
2009 * Remove the cpu slab
2011 static void deactivate_slab(struct kmem_cache *s, struct page *page,
2012 void *freelist, struct kmem_cache_cpu *c)
2014 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
2015 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
2017 enum slab_modes l = M_NONE, m = M_NONE;
2019 int tail = DEACTIVATE_TO_HEAD;
2023 if (page->freelist) {
2024 stat(s, DEACTIVATE_REMOTE_FREES);
2025 tail = DEACTIVATE_TO_TAIL;
2029 * Stage one: Free all available per cpu objects back
2030 * to the page freelist while it is still frozen. Leave the
2033 * There is no need to take the list->lock because the page
2036 while (freelist && (nextfree = get_freepointer(s, freelist))) {
2038 unsigned long counters;
2041 prior = page->freelist;
2042 counters = page->counters;
2043 set_freepointer(s, freelist, prior);
2044 new.counters = counters;
2046 VM_BUG_ON(!new.frozen);
2048 } while (!__cmpxchg_double_slab(s, page,
2050 freelist, new.counters,
2051 "drain percpu freelist"));
2053 freelist = nextfree;
2057 * Stage two: Ensure that the page is unfrozen while the
2058 * list presence reflects the actual number of objects
2061 * We setup the list membership and then perform a cmpxchg
2062 * with the count. If there is a mismatch then the page
2063 * is not unfrozen but the page is on the wrong list.
2065 * Then we restart the process which may have to remove
2066 * the page from the list that we just put it on again
2067 * because the number of objects in the slab may have
2072 old.freelist = page->freelist;
2073 old.counters = page->counters;
2074 VM_BUG_ON(!old.frozen);
2076 /* Determine target state of the slab */
2077 new.counters = old.counters;
2080 set_freepointer(s, freelist, old.freelist);
2081 new.freelist = freelist;
2083 new.freelist = old.freelist;
2087 if (!new.inuse && n->nr_partial >= s->min_partial)
2089 else if (new.freelist) {
2094 * Taking the spinlock removes the possiblity
2095 * that acquire_slab() will see a slab page that
2098 spin_lock(&n->list_lock);
2102 if (kmem_cache_debug(s) && !lock) {
2105 * This also ensures that the scanning of full
2106 * slabs from diagnostic functions will not see
2109 spin_lock(&n->list_lock);
2117 remove_partial(n, page);
2119 else if (l == M_FULL)
2121 remove_full(s, n, page);
2123 if (m == M_PARTIAL) {
2125 add_partial(n, page, tail);
2128 } else if (m == M_FULL) {
2130 stat(s, DEACTIVATE_FULL);
2131 add_full(s, n, page);
2137 if (!__cmpxchg_double_slab(s, page,
2138 old.freelist, old.counters,
2139 new.freelist, new.counters,
2144 spin_unlock(&n->list_lock);
2147 stat(s, DEACTIVATE_EMPTY);
2148 discard_slab(s, page);
2157 * Unfreeze all the cpu partial slabs.
2159 * This function must be called with interrupts disabled
2160 * for the cpu using c (or some other guarantee must be there
2161 * to guarantee no concurrent accesses).
2163 static void unfreeze_partials(struct kmem_cache *s,
2164 struct kmem_cache_cpu *c)
2166 #ifdef CONFIG_SLUB_CPU_PARTIAL
2167 struct kmem_cache_node *n = NULL, *n2 = NULL;
2168 struct page *page, *discard_page = NULL;
2170 while ((page = c->partial)) {
2174 c->partial = page->next;
2176 n2 = get_node(s, page_to_nid(page));
2179 spin_unlock(&n->list_lock);
2182 spin_lock(&n->list_lock);
2187 old.freelist = page->freelist;
2188 old.counters = page->counters;
2189 VM_BUG_ON(!old.frozen);
2191 new.counters = old.counters;
2192 new.freelist = old.freelist;
2196 } while (!__cmpxchg_double_slab(s, page,
2197 old.freelist, old.counters,
2198 new.freelist, new.counters,
2199 "unfreezing slab"));
2201 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2202 page->next = discard_page;
2203 discard_page = page;
2205 add_partial(n, page, DEACTIVATE_TO_TAIL);
2206 stat(s, FREE_ADD_PARTIAL);
2211 spin_unlock(&n->list_lock);
2213 while (discard_page) {
2214 page = discard_page;
2215 discard_page = discard_page->next;
2217 stat(s, DEACTIVATE_EMPTY);
2218 discard_slab(s, page);
2225 * Put a page that was just frozen (in __slab_free) into a partial page
2226 * slot if available.
2228 * If we did not find a slot then simply move all the partials to the
2229 * per node partial list.
2231 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2233 #ifdef CONFIG_SLUB_CPU_PARTIAL
2234 struct page *oldpage;
2242 oldpage = this_cpu_read(s->cpu_slab->partial);
2245 pobjects = oldpage->pobjects;
2246 pages = oldpage->pages;
2247 if (drain && pobjects > s->cpu_partial) {
2248 unsigned long flags;
2250 * partial array is full. Move the existing
2251 * set to the per node partial list.
2253 local_irq_save(flags);
2254 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2255 local_irq_restore(flags);
2259 stat(s, CPU_PARTIAL_DRAIN);
2264 pobjects += page->objects - page->inuse;
2266 page->pages = pages;
2267 page->pobjects = pobjects;
2268 page->next = oldpage;
2270 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2272 if (unlikely(!s->cpu_partial)) {
2273 unsigned long flags;
2275 local_irq_save(flags);
2276 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2277 local_irq_restore(flags);
2283 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2285 stat(s, CPUSLAB_FLUSH);
2286 deactivate_slab(s, c->page, c->freelist, c);
2288 c->tid = next_tid(c->tid);
2294 * Called from IPI handler with interrupts disabled.
2296 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2298 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2304 unfreeze_partials(s, c);
2308 static void flush_cpu_slab(void *d)
2310 struct kmem_cache *s = d;
2312 __flush_cpu_slab(s, smp_processor_id());
2315 static bool has_cpu_slab(int cpu, void *info)
2317 struct kmem_cache *s = info;
2318 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2320 return c->page || slub_percpu_partial(c);
2323 static void flush_all(struct kmem_cache *s)
2325 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2329 * Use the cpu notifier to insure that the cpu slabs are flushed when
2332 static int slub_cpu_dead(unsigned int cpu)
2334 struct kmem_cache *s;
2335 unsigned long flags;
2337 mutex_lock(&slab_mutex);
2338 list_for_each_entry(s, &slab_caches, list) {
2339 local_irq_save(flags);
2340 __flush_cpu_slab(s, cpu);
2341 local_irq_restore(flags);
2343 mutex_unlock(&slab_mutex);
2348 * Check if the objects in a per cpu structure fit numa
2349 * locality expectations.
2351 static inline int node_match(struct page *page, int node)
2354 if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2360 #ifdef CONFIG_SLUB_DEBUG
2361 static int count_free(struct page *page)
2363 return page->objects - page->inuse;
2366 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2368 return atomic_long_read(&n->total_objects);
2370 #endif /* CONFIG_SLUB_DEBUG */
2372 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2373 static unsigned long count_partial(struct kmem_cache_node *n,
2374 int (*get_count)(struct page *))
2376 unsigned long flags;
2377 unsigned long x = 0;
2380 spin_lock_irqsave(&n->list_lock, flags);
2381 list_for_each_entry(page, &n->partial, lru)
2382 x += get_count(page);
2383 spin_unlock_irqrestore(&n->list_lock, flags);
2386 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2388 static noinline void
2389 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2391 #ifdef CONFIG_SLUB_DEBUG
2392 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2393 DEFAULT_RATELIMIT_BURST);
2395 struct kmem_cache_node *n;
2397 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2400 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2401 nid, gfpflags, &gfpflags);
2402 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %d, min order: %d\n",
2403 s->name, s->object_size, s->size, oo_order(s->oo),
2406 if (oo_order(s->min) > get_order(s->object_size))
2407 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2410 for_each_kmem_cache_node(s, node, n) {
2411 unsigned long nr_slabs;
2412 unsigned long nr_objs;
2413 unsigned long nr_free;
2415 nr_free = count_partial(n, count_free);
2416 nr_slabs = node_nr_slabs(n);
2417 nr_objs = node_nr_objs(n);
2419 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2420 node, nr_slabs, nr_objs, nr_free);
2425 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2426 int node, struct kmem_cache_cpu **pc)
2429 struct kmem_cache_cpu *c = *pc;
2432 freelist = get_partial(s, flags, node, c);
2437 page = new_slab(s, flags, node);
2439 c = raw_cpu_ptr(s->cpu_slab);
2444 * No other reference to the page yet so we can
2445 * muck around with it freely without cmpxchg
2447 freelist = page->freelist;
2448 page->freelist = NULL;
2450 stat(s, ALLOC_SLAB);
2459 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2461 if (unlikely(PageSlabPfmemalloc(page)))
2462 return gfp_pfmemalloc_allowed(gfpflags);
2468 * Check the page->freelist of a page and either transfer the freelist to the
2469 * per cpu freelist or deactivate the page.
2471 * The page is still frozen if the return value is not NULL.
2473 * If this function returns NULL then the page has been unfrozen.
2475 * This function must be called with interrupt disabled.
2477 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2480 unsigned long counters;
2484 freelist = page->freelist;
2485 counters = page->counters;
2487 new.counters = counters;
2488 VM_BUG_ON(!new.frozen);
2490 new.inuse = page->objects;
2491 new.frozen = freelist != NULL;
2493 } while (!__cmpxchg_double_slab(s, page,
2502 * Slow path. The lockless freelist is empty or we need to perform
2505 * Processing is still very fast if new objects have been freed to the
2506 * regular freelist. In that case we simply take over the regular freelist
2507 * as the lockless freelist and zap the regular freelist.
2509 * If that is not working then we fall back to the partial lists. We take the
2510 * first element of the freelist as the object to allocate now and move the
2511 * rest of the freelist to the lockless freelist.
2513 * And if we were unable to get a new slab from the partial slab lists then
2514 * we need to allocate a new slab. This is the slowest path since it involves
2515 * a call to the page allocator and the setup of a new slab.
2517 * Version of __slab_alloc to use when we know that interrupts are
2518 * already disabled (which is the case for bulk allocation).
2520 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2521 unsigned long addr, struct kmem_cache_cpu *c)
2531 if (unlikely(!node_match(page, node))) {
2532 int searchnode = node;
2534 if (node != NUMA_NO_NODE && !node_present_pages(node))
2535 searchnode = node_to_mem_node(node);
2537 if (unlikely(!node_match(page, searchnode))) {
2538 stat(s, ALLOC_NODE_MISMATCH);
2539 deactivate_slab(s, page, c->freelist, c);
2545 * By rights, we should be searching for a slab page that was
2546 * PFMEMALLOC but right now, we are losing the pfmemalloc
2547 * information when the page leaves the per-cpu allocator
2549 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2550 deactivate_slab(s, page, c->freelist, c);
2554 /* must check again c->freelist in case of cpu migration or IRQ */
2555 freelist = c->freelist;
2559 freelist = get_freelist(s, page);
2563 stat(s, DEACTIVATE_BYPASS);
2567 stat(s, ALLOC_REFILL);
2571 * freelist is pointing to the list of objects to be used.
2572 * page is pointing to the page from which the objects are obtained.
2573 * That page must be frozen for per cpu allocations to work.
2575 VM_BUG_ON(!c->page->frozen);
2576 c->freelist = get_freepointer(s, freelist);
2577 c->tid = next_tid(c->tid);
2582 if (slub_percpu_partial(c)) {
2583 page = c->page = slub_percpu_partial(c);
2584 slub_set_percpu_partial(c, page);
2585 stat(s, CPU_PARTIAL_ALLOC);
2589 freelist = new_slab_objects(s, gfpflags, node, &c);
2591 if (unlikely(!freelist)) {
2592 slab_out_of_memory(s, gfpflags, node);
2597 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2600 /* Only entered in the debug case */
2601 if (kmem_cache_debug(s) &&
2602 !alloc_debug_processing(s, page, freelist, addr))
2603 goto new_slab; /* Slab failed checks. Next slab needed */
2605 deactivate_slab(s, page, get_freepointer(s, freelist), c);
2610 * Another one that disabled interrupt and compensates for possible
2611 * cpu changes by refetching the per cpu area pointer.
2613 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2614 unsigned long addr, struct kmem_cache_cpu *c)
2617 unsigned long flags;
2619 local_irq_save(flags);
2620 #ifdef CONFIG_PREEMPT
2622 * We may have been preempted and rescheduled on a different
2623 * cpu before disabling interrupts. Need to reload cpu area
2626 c = this_cpu_ptr(s->cpu_slab);
2629 p = ___slab_alloc(s, gfpflags, node, addr, c);
2630 local_irq_restore(flags);
2635 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2636 * have the fastpath folded into their functions. So no function call
2637 * overhead for requests that can be satisfied on the fastpath.
2639 * The fastpath works by first checking if the lockless freelist can be used.
2640 * If not then __slab_alloc is called for slow processing.
2642 * Otherwise we can simply pick the next object from the lockless free list.
2644 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2645 gfp_t gfpflags, int node, unsigned long addr)
2648 struct kmem_cache_cpu *c;
2652 s = slab_pre_alloc_hook(s, gfpflags);
2657 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2658 * enabled. We may switch back and forth between cpus while
2659 * reading from one cpu area. That does not matter as long
2660 * as we end up on the original cpu again when doing the cmpxchg.
2662 * We should guarantee that tid and kmem_cache are retrieved on
2663 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2664 * to check if it is matched or not.
2667 tid = this_cpu_read(s->cpu_slab->tid);
2668 c = raw_cpu_ptr(s->cpu_slab);
2669 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2670 unlikely(tid != READ_ONCE(c->tid)));
2673 * Irqless object alloc/free algorithm used here depends on sequence
2674 * of fetching cpu_slab's data. tid should be fetched before anything
2675 * on c to guarantee that object and page associated with previous tid
2676 * won't be used with current tid. If we fetch tid first, object and
2677 * page could be one associated with next tid and our alloc/free
2678 * request will be failed. In this case, we will retry. So, no problem.
2683 * The transaction ids are globally unique per cpu and per operation on
2684 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2685 * occurs on the right processor and that there was no operation on the
2686 * linked list in between.
2689 object = c->freelist;
2691 if (unlikely(!object || !node_match(page, node))) {
2692 object = __slab_alloc(s, gfpflags, node, addr, c);
2693 stat(s, ALLOC_SLOWPATH);
2695 void *next_object = get_freepointer_safe(s, object);
2698 * The cmpxchg will only match if there was no additional
2699 * operation and if we are on the right processor.
2701 * The cmpxchg does the following atomically (without lock
2703 * 1. Relocate first pointer to the current per cpu area.
2704 * 2. Verify that tid and freelist have not been changed
2705 * 3. If they were not changed replace tid and freelist
2707 * Since this is without lock semantics the protection is only
2708 * against code executing on this cpu *not* from access by
2711 if (unlikely(!this_cpu_cmpxchg_double(
2712 s->cpu_slab->freelist, s->cpu_slab->tid,
2714 next_object, next_tid(tid)))) {
2716 note_cmpxchg_failure("slab_alloc", s, tid);
2719 prefetch_freepointer(s, next_object);
2720 stat(s, ALLOC_FASTPATH);
2723 if (unlikely(gfpflags & __GFP_ZERO) && object)
2724 memset(object, 0, s->object_size);
2726 slab_post_alloc_hook(s, gfpflags, 1, &object);
2731 static __always_inline void *slab_alloc(struct kmem_cache *s,
2732 gfp_t gfpflags, unsigned long addr)
2734 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2737 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2739 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2741 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2746 EXPORT_SYMBOL(kmem_cache_alloc);
2748 #ifdef CONFIG_TRACING
2749 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2751 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2752 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2753 kasan_kmalloc(s, ret, size, gfpflags);
2756 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2760 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2762 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2764 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2765 s->object_size, s->size, gfpflags, node);
2769 EXPORT_SYMBOL(kmem_cache_alloc_node);
2771 #ifdef CONFIG_TRACING
2772 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2774 int node, size_t size)
2776 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2778 trace_kmalloc_node(_RET_IP_, ret,
2779 size, s->size, gfpflags, node);
2781 kasan_kmalloc(s, ret, size, gfpflags);
2784 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2789 * Slow path handling. This may still be called frequently since objects
2790 * have a longer lifetime than the cpu slabs in most processing loads.
2792 * So we still attempt to reduce cache line usage. Just take the slab
2793 * lock and free the item. If there is no additional partial page
2794 * handling required then we can return immediately.
2796 static void __slab_free(struct kmem_cache *s, struct page *page,
2797 void *head, void *tail, int cnt,
2804 unsigned long counters;
2805 struct kmem_cache_node *n = NULL;
2806 unsigned long uninitialized_var(flags);
2808 stat(s, FREE_SLOWPATH);
2810 if (kmem_cache_debug(s) &&
2811 !free_debug_processing(s, page, head, tail, cnt, addr))
2816 spin_unlock_irqrestore(&n->list_lock, flags);
2819 prior = page->freelist;
2820 counters = page->counters;
2821 set_freepointer(s, tail, prior);
2822 new.counters = counters;
2823 was_frozen = new.frozen;
2825 if ((!new.inuse || !prior) && !was_frozen) {
2827 if (kmem_cache_has_cpu_partial(s) && !prior) {
2830 * Slab was on no list before and will be
2832 * We can defer the list move and instead
2837 } else { /* Needs to be taken off a list */
2839 n = get_node(s, page_to_nid(page));
2841 * Speculatively acquire the list_lock.
2842 * If the cmpxchg does not succeed then we may
2843 * drop the list_lock without any processing.
2845 * Otherwise the list_lock will synchronize with
2846 * other processors updating the list of slabs.
2848 spin_lock_irqsave(&n->list_lock, flags);
2853 } while (!cmpxchg_double_slab(s, page,
2861 * If we just froze the page then put it onto the
2862 * per cpu partial list.
2864 if (new.frozen && !was_frozen) {
2865 put_cpu_partial(s, page, 1);
2866 stat(s, CPU_PARTIAL_FREE);
2869 * The list lock was not taken therefore no list
2870 * activity can be necessary.
2873 stat(s, FREE_FROZEN);
2877 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2881 * Objects left in the slab. If it was not on the partial list before
2884 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2885 if (kmem_cache_debug(s))
2886 remove_full(s, n, page);
2887 add_partial(n, page, DEACTIVATE_TO_TAIL);
2888 stat(s, FREE_ADD_PARTIAL);
2890 spin_unlock_irqrestore(&n->list_lock, flags);
2896 * Slab on the partial list.
2898 remove_partial(n, page);
2899 stat(s, FREE_REMOVE_PARTIAL);
2901 /* Slab must be on the full list */
2902 remove_full(s, n, page);
2905 spin_unlock_irqrestore(&n->list_lock, flags);
2907 discard_slab(s, page);
2911 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2912 * can perform fastpath freeing without additional function calls.
2914 * The fastpath is only possible if we are freeing to the current cpu slab
2915 * of this processor. This typically the case if we have just allocated
2918 * If fastpath is not possible then fall back to __slab_free where we deal
2919 * with all sorts of special processing.
2921 * Bulk free of a freelist with several objects (all pointing to the
2922 * same page) possible by specifying head and tail ptr, plus objects
2923 * count (cnt). Bulk free indicated by tail pointer being set.
2925 static __always_inline void do_slab_free(struct kmem_cache *s,
2926 struct page *page, void *head, void *tail,
2927 int cnt, unsigned long addr)
2929 void *tail_obj = tail ? : head;
2930 struct kmem_cache_cpu *c;
2934 * Determine the currently cpus per cpu slab.
2935 * The cpu may change afterward. However that does not matter since
2936 * data is retrieved via this pointer. If we are on the same cpu
2937 * during the cmpxchg then the free will succeed.
2940 tid = this_cpu_read(s->cpu_slab->tid);
2941 c = raw_cpu_ptr(s->cpu_slab);
2942 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2943 unlikely(tid != READ_ONCE(c->tid)));
2945 /* Same with comment on barrier() in slab_alloc_node() */
2948 if (likely(page == c->page)) {
2949 set_freepointer(s, tail_obj, c->freelist);
2951 if (unlikely(!this_cpu_cmpxchg_double(
2952 s->cpu_slab->freelist, s->cpu_slab->tid,
2954 head, next_tid(tid)))) {
2956 note_cmpxchg_failure("slab_free", s, tid);
2959 stat(s, FREE_FASTPATH);
2961 __slab_free(s, page, head, tail_obj, cnt, addr);
2965 static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2966 void *head, void *tail, int cnt,
2969 slab_free_freelist_hook(s, head, tail);
2971 * slab_free_freelist_hook() could have put the items into quarantine.
2972 * If so, no need to free them.
2974 if (s->flags & SLAB_KASAN && !(s->flags & SLAB_TYPESAFE_BY_RCU))
2976 do_slab_free(s, page, head, tail, cnt, addr);
2980 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
2982 do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
2986 void kmem_cache_free(struct kmem_cache *s, void *x)
2988 s = cache_from_obj(s, x);
2991 slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
2992 trace_kmem_cache_free(_RET_IP_, x);
2994 EXPORT_SYMBOL(kmem_cache_free);
2996 struct detached_freelist {
3001 struct kmem_cache *s;
3005 * This function progressively scans the array with free objects (with
3006 * a limited look ahead) and extract objects belonging to the same
3007 * page. It builds a detached freelist directly within the given
3008 * page/objects. This can happen without any need for
3009 * synchronization, because the objects are owned by running process.
3010 * The freelist is build up as a single linked list in the objects.
3011 * The idea is, that this detached freelist can then be bulk
3012 * transferred to the real freelist(s), but only requiring a single
3013 * synchronization primitive. Look ahead in the array is limited due
3014 * to performance reasons.
3017 int build_detached_freelist(struct kmem_cache *s, size_t size,
3018 void **p, struct detached_freelist *df)
3020 size_t first_skipped_index = 0;
3025 /* Always re-init detached_freelist */
3030 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3031 } while (!object && size);
3036 page = virt_to_head_page(object);
3038 /* Handle kalloc'ed objects */
3039 if (unlikely(!PageSlab(page))) {
3040 BUG_ON(!PageCompound(page));
3042 __free_pages(page, compound_order(page));
3043 p[size] = NULL; /* mark object processed */
3046 /* Derive kmem_cache from object */
3047 df->s = page->slab_cache;
3049 df->s = cache_from_obj(s, object); /* Support for memcg */
3052 /* Start new detached freelist */
3054 set_freepointer(df->s, object, NULL);
3056 df->freelist = object;
3057 p[size] = NULL; /* mark object processed */
3063 continue; /* Skip processed objects */
3065 /* df->page is always set at this point */
3066 if (df->page == virt_to_head_page(object)) {
3067 /* Opportunity build freelist */
3068 set_freepointer(df->s, object, df->freelist);
3069 df->freelist = object;
3071 p[size] = NULL; /* mark object processed */
3076 /* Limit look ahead search */
3080 if (!first_skipped_index)
3081 first_skipped_index = size + 1;
3084 return first_skipped_index;
3087 /* Note that interrupts must be enabled when calling this function. */
3088 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3094 struct detached_freelist df;
3096 size = build_detached_freelist(s, size, p, &df);
3100 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3101 } while (likely(size));
3103 EXPORT_SYMBOL(kmem_cache_free_bulk);
3105 /* Note that interrupts must be enabled when calling this function. */
3106 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3109 struct kmem_cache_cpu *c;
3112 /* memcg and kmem_cache debug support */
3113 s = slab_pre_alloc_hook(s, flags);
3117 * Drain objects in the per cpu slab, while disabling local
3118 * IRQs, which protects against PREEMPT and interrupts
3119 * handlers invoking normal fastpath.
3121 local_irq_disable();
3122 c = this_cpu_ptr(s->cpu_slab);
3124 for (i = 0; i < size; i++) {
3125 void *object = c->freelist;
3127 if (unlikely(!object)) {
3129 * Invoking slow path likely have side-effect
3130 * of re-populating per CPU c->freelist
3132 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3134 if (unlikely(!p[i]))
3137 c = this_cpu_ptr(s->cpu_slab);
3138 continue; /* goto for-loop */
3140 c->freelist = get_freepointer(s, object);
3143 c->tid = next_tid(c->tid);
3146 /* Clear memory outside IRQ disabled fastpath loop */
3147 if (unlikely(flags & __GFP_ZERO)) {
3150 for (j = 0; j < i; j++)
3151 memset(p[j], 0, s->object_size);
3154 /* memcg and kmem_cache debug support */
3155 slab_post_alloc_hook(s, flags, size, p);
3159 slab_post_alloc_hook(s, flags, i, p);
3160 __kmem_cache_free_bulk(s, i, p);
3163 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3167 * Object placement in a slab is made very easy because we always start at
3168 * offset 0. If we tune the size of the object to the alignment then we can
3169 * get the required alignment by putting one properly sized object after
3172 * Notice that the allocation order determines the sizes of the per cpu
3173 * caches. Each processor has always one slab available for allocations.
3174 * Increasing the allocation order reduces the number of times that slabs
3175 * must be moved on and off the partial lists and is therefore a factor in
3180 * Mininum / Maximum order of slab pages. This influences locking overhead
3181 * and slab fragmentation. A higher order reduces the number of partial slabs
3182 * and increases the number of allocations possible without having to
3183 * take the list_lock.
3185 static int slub_min_order;
3186 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3187 static int slub_min_objects;
3190 * Calculate the order of allocation given an slab object size.
3192 * The order of allocation has significant impact on performance and other
3193 * system components. Generally order 0 allocations should be preferred since
3194 * order 0 does not cause fragmentation in the page allocator. Larger objects
3195 * be problematic to put into order 0 slabs because there may be too much
3196 * unused space left. We go to a higher order if more than 1/16th of the slab
3199 * In order to reach satisfactory performance we must ensure that a minimum
3200 * number of objects is in one slab. Otherwise we may generate too much
3201 * activity on the partial lists which requires taking the list_lock. This is
3202 * less a concern for large slabs though which are rarely used.
3204 * slub_max_order specifies the order where we begin to stop considering the
3205 * number of objects in a slab as critical. If we reach slub_max_order then
3206 * we try to keep the page order as low as possible. So we accept more waste
3207 * of space in favor of a small page order.
3209 * Higher order allocations also allow the placement of more objects in a
3210 * slab and thereby reduce object handling overhead. If the user has
3211 * requested a higher mininum order then we start with that one instead of
3212 * the smallest order which will fit the object.
3214 static inline int slab_order(int size, int min_objects,
3215 int max_order, int fract_leftover, int reserved)
3219 int min_order = slub_min_order;
3221 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
3222 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3224 for (order = max(min_order, get_order(min_objects * size + reserved));
3225 order <= max_order; order++) {
3227 unsigned long slab_size = PAGE_SIZE << order;
3229 rem = (slab_size - reserved) % size;
3231 if (rem <= slab_size / fract_leftover)
3238 static inline int calculate_order(int size, int reserved)
3246 * Attempt to find best configuration for a slab. This
3247 * works by first attempting to generate a layout with
3248 * the best configuration and backing off gradually.
3250 * First we increase the acceptable waste in a slab. Then
3251 * we reduce the minimum objects required in a slab.
3253 min_objects = slub_min_objects;
3255 min_objects = 4 * (fls(nr_cpu_ids) + 1);
3256 max_objects = order_objects(slub_max_order, size, reserved);
3257 min_objects = min(min_objects, max_objects);
3259 while (min_objects > 1) {
3261 while (fraction >= 4) {
3262 order = slab_order(size, min_objects,
3263 slub_max_order, fraction, reserved);
3264 if (order <= slub_max_order)
3272 * We were unable to place multiple objects in a slab. Now
3273 * lets see if we can place a single object there.
3275 order = slab_order(size, 1, slub_max_order, 1, reserved);
3276 if (order <= slub_max_order)
3280 * Doh this slab cannot be placed using slub_max_order.
3282 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
3283 if (order < MAX_ORDER)
3289 init_kmem_cache_node(struct kmem_cache_node *n)
3292 spin_lock_init(&n->list_lock);
3293 INIT_LIST_HEAD(&n->partial);
3294 #ifdef CONFIG_SLUB_DEBUG
3295 atomic_long_set(&n->nr_slabs, 0);
3296 atomic_long_set(&n->total_objects, 0);
3297 INIT_LIST_HEAD(&n->full);
3301 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3303 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3304 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3307 * Must align to double word boundary for the double cmpxchg
3308 * instructions to work; see __pcpu_double_call_return_bool().
3310 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3311 2 * sizeof(void *));
3316 init_kmem_cache_cpus(s);
3321 static struct kmem_cache *kmem_cache_node;
3324 * No kmalloc_node yet so do it by hand. We know that this is the first
3325 * slab on the node for this slabcache. There are no concurrent accesses
3328 * Note that this function only works on the kmem_cache_node
3329 * when allocating for the kmem_cache_node. This is used for bootstrapping
3330 * memory on a fresh node that has no slab structures yet.
3332 static void early_kmem_cache_node_alloc(int node)
3335 struct kmem_cache_node *n;
3337 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3339 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3342 if (page_to_nid(page) != node) {
3343 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3344 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3349 page->freelist = get_freepointer(kmem_cache_node, n);
3352 kmem_cache_node->node[node] = n;
3353 #ifdef CONFIG_SLUB_DEBUG
3354 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3355 init_tracking(kmem_cache_node, n);
3357 kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3359 init_kmem_cache_node(n);
3360 inc_slabs_node(kmem_cache_node, node, page->objects);
3363 * No locks need to be taken here as it has just been
3364 * initialized and there is no concurrent access.
3366 __add_partial(n, page, DEACTIVATE_TO_HEAD);
3369 static void free_kmem_cache_nodes(struct kmem_cache *s)
3372 struct kmem_cache_node *n;
3374 for_each_kmem_cache_node(s, node, n) {
3375 s->node[node] = NULL;
3376 kmem_cache_free(kmem_cache_node, n);
3380 void __kmem_cache_release(struct kmem_cache *s)
3382 cache_random_seq_destroy(s);
3383 free_percpu(s->cpu_slab);
3384 free_kmem_cache_nodes(s);
3387 static int init_kmem_cache_nodes(struct kmem_cache *s)
3391 for_each_node_state(node, N_NORMAL_MEMORY) {
3392 struct kmem_cache_node *n;
3394 if (slab_state == DOWN) {
3395 early_kmem_cache_node_alloc(node);
3398 n = kmem_cache_alloc_node(kmem_cache_node,
3402 free_kmem_cache_nodes(s);
3406 init_kmem_cache_node(n);
3412 static void set_min_partial(struct kmem_cache *s, unsigned long min)
3414 if (min < MIN_PARTIAL)
3416 else if (min > MAX_PARTIAL)
3418 s->min_partial = min;
3421 static void set_cpu_partial(struct kmem_cache *s)
3423 #ifdef CONFIG_SLUB_CPU_PARTIAL
3425 * cpu_partial determined the maximum number of objects kept in the
3426 * per cpu partial lists of a processor.
3428 * Per cpu partial lists mainly contain slabs that just have one
3429 * object freed. If they are used for allocation then they can be
3430 * filled up again with minimal effort. The slab will never hit the
3431 * per node partial lists and therefore no locking will be required.
3433 * This setting also determines
3435 * A) The number of objects from per cpu partial slabs dumped to the
3436 * per node list when we reach the limit.
3437 * B) The number of objects in cpu partial slabs to extract from the
3438 * per node list when we run out of per cpu objects. We only fetch
3439 * 50% to keep some capacity around for frees.
3441 if (!kmem_cache_has_cpu_partial(s))
3443 else if (s->size >= PAGE_SIZE)
3445 else if (s->size >= 1024)
3447 else if (s->size >= 256)
3448 s->cpu_partial = 13;
3450 s->cpu_partial = 30;
3455 * calculate_sizes() determines the order and the distribution of data within
3458 static int calculate_sizes(struct kmem_cache *s, int forced_order)
3460 slab_flags_t flags = s->flags;
3461 unsigned int size = s->object_size;
3465 * Round up object size to the next word boundary. We can only
3466 * place the free pointer at word boundaries and this determines
3467 * the possible location of the free pointer.
3469 size = ALIGN(size, sizeof(void *));
3471 #ifdef CONFIG_SLUB_DEBUG
3473 * Determine if we can poison the object itself. If the user of
3474 * the slab may touch the object after free or before allocation
3475 * then we should never poison the object itself.
3477 if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
3479 s->flags |= __OBJECT_POISON;
3481 s->flags &= ~__OBJECT_POISON;
3485 * If we are Redzoning then check if there is some space between the
3486 * end of the object and the free pointer. If not then add an
3487 * additional word to have some bytes to store Redzone information.
3489 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3490 size += sizeof(void *);
3494 * With that we have determined the number of bytes in actual use
3495 * by the object. This is the potential offset to the free pointer.
3499 if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
3502 * Relocate free pointer after the object if it is not
3503 * permitted to overwrite the first word of the object on
3506 * This is the case if we do RCU, have a constructor or
3507 * destructor or are poisoning the objects.
3510 size += sizeof(void *);
3513 #ifdef CONFIG_SLUB_DEBUG
3514 if (flags & SLAB_STORE_USER)
3516 * Need to store information about allocs and frees after
3519 size += 2 * sizeof(struct track);
3522 kasan_cache_create(s, &size, &s->flags);
3523 #ifdef CONFIG_SLUB_DEBUG
3524 if (flags & SLAB_RED_ZONE) {
3526 * Add some empty padding so that we can catch
3527 * overwrites from earlier objects rather than let
3528 * tracking information or the free pointer be
3529 * corrupted if a user writes before the start
3532 size += sizeof(void *);
3534 s->red_left_pad = sizeof(void *);
3535 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3536 size += s->red_left_pad;
3541 * SLUB stores one object immediately after another beginning from
3542 * offset 0. In order to align the objects we have to simply size
3543 * each object to conform to the alignment.
3545 size = ALIGN(size, s->align);
3547 if (forced_order >= 0)
3548 order = forced_order;
3550 order = calculate_order(size, s->reserved);
3557 s->allocflags |= __GFP_COMP;
3559 if (s->flags & SLAB_CACHE_DMA)
3560 s->allocflags |= GFP_DMA;
3562 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3563 s->allocflags |= __GFP_RECLAIMABLE;
3566 * Determine the number of objects per slab
3568 s->oo = oo_make(order, size, s->reserved);
3569 s->min = oo_make(get_order(size), size, s->reserved);
3570 if (oo_objects(s->oo) > oo_objects(s->max))
3573 return !!oo_objects(s->oo);
3576 static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
3578 s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3580 #ifdef CONFIG_SLAB_FREELIST_HARDENED
3581 s->random = get_random_long();
3584 if (need_reserve_slab_rcu && (s->flags & SLAB_TYPESAFE_BY_RCU))
3585 s->reserved = sizeof(struct rcu_head);
3587 if (!calculate_sizes(s, -1))
3589 if (disable_higher_order_debug) {
3591 * Disable debugging flags that store metadata if the min slab
3594 if (get_order(s->size) > get_order(s->object_size)) {
3595 s->flags &= ~DEBUG_METADATA_FLAGS;
3597 if (!calculate_sizes(s, -1))
3602 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3603 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3604 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3605 /* Enable fast mode */
3606 s->flags |= __CMPXCHG_DOUBLE;
3610 * The larger the object size is, the more pages we want on the partial
3611 * list to avoid pounding the page allocator excessively.
3613 set_min_partial(s, ilog2(s->size) / 2);
3618 s->remote_node_defrag_ratio = 1000;
3621 /* Initialize the pre-computed randomized freelist if slab is up */
3622 if (slab_state >= UP) {
3623 if (init_cache_random_seq(s))
3627 if (!init_kmem_cache_nodes(s))
3630 if (alloc_kmem_cache_cpus(s))
3633 free_kmem_cache_nodes(s);
3635 if (flags & SLAB_PANIC)
3636 panic("Cannot create slab %s size=%u realsize=%u order=%u offset=%u flags=%lx\n",
3637 s->name, s->size, s->size,
3638 oo_order(s->oo), s->offset, (unsigned long)flags);
3642 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3645 #ifdef CONFIG_SLUB_DEBUG
3646 void *addr = page_address(page);
3648 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3649 sizeof(long), GFP_ATOMIC);
3652 slab_err(s, page, text, s->name);
3655 get_map(s, page, map);
3656 for_each_object(p, s, addr, page->objects) {
3658 if (!test_bit(slab_index(p, s, addr), map)) {
3659 pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3660 print_tracking(s, p);
3669 * Attempt to free all partial slabs on a node.
3670 * This is called from __kmem_cache_shutdown(). We must take list_lock
3671 * because sysfs file might still access partial list after the shutdowning.
3673 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3676 struct page *page, *h;
3678 BUG_ON(irqs_disabled());
3679 spin_lock_irq(&n->list_lock);
3680 list_for_each_entry_safe(page, h, &n->partial, lru) {
3682 remove_partial(n, page);
3683 list_add(&page->lru, &discard);
3685 list_slab_objects(s, page,
3686 "Objects remaining in %s on __kmem_cache_shutdown()");
3689 spin_unlock_irq(&n->list_lock);
3691 list_for_each_entry_safe(page, h, &discard, lru)
3692 discard_slab(s, page);
3696 * Release all resources used by a slab cache.
3698 int __kmem_cache_shutdown(struct kmem_cache *s)
3701 struct kmem_cache_node *n;
3704 /* Attempt to free all objects */
3705 for_each_kmem_cache_node(s, node, n) {
3707 if (n->nr_partial || slabs_node(s, node))
3710 sysfs_slab_remove(s);
3714 /********************************************************************
3716 *******************************************************************/
3718 static int __init setup_slub_min_order(char *str)
3720 get_option(&str, &slub_min_order);
3725 __setup("slub_min_order=", setup_slub_min_order);
3727 static int __init setup_slub_max_order(char *str)
3729 get_option(&str, &slub_max_order);
3730 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3735 __setup("slub_max_order=", setup_slub_max_order);
3737 static int __init setup_slub_min_objects(char *str)
3739 get_option(&str, &slub_min_objects);
3744 __setup("slub_min_objects=", setup_slub_min_objects);
3746 void *__kmalloc(size_t size, gfp_t flags)
3748 struct kmem_cache *s;
3751 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3752 return kmalloc_large(size, flags);
3754 s = kmalloc_slab(size, flags);
3756 if (unlikely(ZERO_OR_NULL_PTR(s)))
3759 ret = slab_alloc(s, flags, _RET_IP_);
3761 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3763 kasan_kmalloc(s, ret, size, flags);
3767 EXPORT_SYMBOL(__kmalloc);
3770 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3775 flags |= __GFP_COMP;
3776 page = alloc_pages_node(node, flags, get_order(size));
3778 ptr = page_address(page);
3780 kmalloc_large_node_hook(ptr, size, flags);
3784 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3786 struct kmem_cache *s;
3789 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3790 ret = kmalloc_large_node(size, flags, node);
3792 trace_kmalloc_node(_RET_IP_, ret,
3793 size, PAGE_SIZE << get_order(size),
3799 s = kmalloc_slab(size, flags);
3801 if (unlikely(ZERO_OR_NULL_PTR(s)))
3804 ret = slab_alloc_node(s, flags, node, _RET_IP_);
3806 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3808 kasan_kmalloc(s, ret, size, flags);
3812 EXPORT_SYMBOL(__kmalloc_node);
3815 #ifdef CONFIG_HARDENED_USERCOPY
3817 * Rejects incorrectly sized objects and objects that are to be copied
3818 * to/from userspace but do not fall entirely within the containing slab
3819 * cache's usercopy region.
3821 * Returns NULL if check passes, otherwise const char * to name of cache
3822 * to indicate an error.
3824 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
3827 struct kmem_cache *s;
3828 unsigned int offset;
3831 /* Find object and usable object size. */
3832 s = page->slab_cache;
3834 /* Reject impossible pointers. */
3835 if (ptr < page_address(page))
3836 usercopy_abort("SLUB object not in SLUB page?!", NULL,
3839 /* Find offset within object. */
3840 offset = (ptr - page_address(page)) % s->size;
3842 /* Adjust for redzone and reject if within the redzone. */
3843 if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
3844 if (offset < s->red_left_pad)
3845 usercopy_abort("SLUB object in left red zone",
3846 s->name, to_user, offset, n);
3847 offset -= s->red_left_pad;
3850 /* Allow address range falling entirely within usercopy region. */
3851 if (offset >= s->useroffset &&
3852 offset - s->useroffset <= s->usersize &&
3853 n <= s->useroffset - offset + s->usersize)
3857 * If the copy is still within the allocated object, produce
3858 * a warning instead of rejecting the copy. This is intended
3859 * to be a temporary method to find any missing usercopy
3862 object_size = slab_ksize(s);
3863 if (usercopy_fallback &&
3864 offset <= object_size && n <= object_size - offset) {
3865 usercopy_warn("SLUB object", s->name, to_user, offset, n);
3869 usercopy_abort("SLUB object", s->name, to_user, offset, n);
3871 #endif /* CONFIG_HARDENED_USERCOPY */
3873 static size_t __ksize(const void *object)
3877 if (unlikely(object == ZERO_SIZE_PTR))
3880 page = virt_to_head_page(object);
3882 if (unlikely(!PageSlab(page))) {
3883 WARN_ON(!PageCompound(page));
3884 return PAGE_SIZE << compound_order(page);
3887 return slab_ksize(page->slab_cache);
3890 size_t ksize(const void *object)
3892 size_t size = __ksize(object);
3893 /* We assume that ksize callers could use whole allocated area,
3894 * so we need to unpoison this area.
3896 kasan_unpoison_shadow(object, size);
3899 EXPORT_SYMBOL(ksize);
3901 void kfree(const void *x)
3904 void *object = (void *)x;
3906 trace_kfree(_RET_IP_, x);
3908 if (unlikely(ZERO_OR_NULL_PTR(x)))
3911 page = virt_to_head_page(x);
3912 if (unlikely(!PageSlab(page))) {
3913 BUG_ON(!PageCompound(page));
3915 __free_pages(page, compound_order(page));
3918 slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3920 EXPORT_SYMBOL(kfree);
3922 #define SHRINK_PROMOTE_MAX 32
3925 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3926 * up most to the head of the partial lists. New allocations will then
3927 * fill those up and thus they can be removed from the partial lists.
3929 * The slabs with the least items are placed last. This results in them
3930 * being allocated from last increasing the chance that the last objects
3931 * are freed in them.
3933 int __kmem_cache_shrink(struct kmem_cache *s)
3937 struct kmem_cache_node *n;
3940 struct list_head discard;
3941 struct list_head promote[SHRINK_PROMOTE_MAX];
3942 unsigned long flags;
3946 for_each_kmem_cache_node(s, node, n) {
3947 INIT_LIST_HEAD(&discard);
3948 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3949 INIT_LIST_HEAD(promote + i);
3951 spin_lock_irqsave(&n->list_lock, flags);
3954 * Build lists of slabs to discard or promote.
3956 * Note that concurrent frees may occur while we hold the
3957 * list_lock. page->inuse here is the upper limit.
3959 list_for_each_entry_safe(page, t, &n->partial, lru) {
3960 int free = page->objects - page->inuse;
3962 /* Do not reread page->inuse */
3965 /* We do not keep full slabs on the list */
3968 if (free == page->objects) {
3969 list_move(&page->lru, &discard);
3971 } else if (free <= SHRINK_PROMOTE_MAX)
3972 list_move(&page->lru, promote + free - 1);
3976 * Promote the slabs filled up most to the head of the
3979 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
3980 list_splice(promote + i, &n->partial);
3982 spin_unlock_irqrestore(&n->list_lock, flags);
3984 /* Release empty slabs */
3985 list_for_each_entry_safe(page, t, &discard, lru)
3986 discard_slab(s, page);
3988 if (slabs_node(s, node))
3996 static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s)
3999 * Called with all the locks held after a sched RCU grace period.
4000 * Even if @s becomes empty after shrinking, we can't know that @s
4001 * doesn't have allocations already in-flight and thus can't
4002 * destroy @s until the associated memcg is released.
4004 * However, let's remove the sysfs files for empty caches here.
4005 * Each cache has a lot of interface files which aren't
4006 * particularly useful for empty draining caches; otherwise, we can
4007 * easily end up with millions of unnecessary sysfs files on
4008 * systems which have a lot of memory and transient cgroups.
4010 if (!__kmem_cache_shrink(s))
4011 sysfs_slab_remove(s);
4014 void __kmemcg_cache_deactivate(struct kmem_cache *s)
4017 * Disable empty slabs caching. Used to avoid pinning offline
4018 * memory cgroups by kmem pages that can be freed.
4020 slub_set_cpu_partial(s, 0);
4024 * s->cpu_partial is checked locklessly (see put_cpu_partial), so
4025 * we have to make sure the change is visible before shrinking.
4027 slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu);
4031 static int slab_mem_going_offline_callback(void *arg)
4033 struct kmem_cache *s;
4035 mutex_lock(&slab_mutex);
4036 list_for_each_entry(s, &slab_caches, list)
4037 __kmem_cache_shrink(s);
4038 mutex_unlock(&slab_mutex);
4043 static void slab_mem_offline_callback(void *arg)
4045 struct kmem_cache_node *n;
4046 struct kmem_cache *s;
4047 struct memory_notify *marg = arg;
4050 offline_node = marg->status_change_nid_normal;
4053 * If the node still has available memory. we need kmem_cache_node
4056 if (offline_node < 0)
4059 mutex_lock(&slab_mutex);
4060 list_for_each_entry(s, &slab_caches, list) {
4061 n = get_node(s, offline_node);
4064 * if n->nr_slabs > 0, slabs still exist on the node
4065 * that is going down. We were unable to free them,
4066 * and offline_pages() function shouldn't call this
4067 * callback. So, we must fail.
4069 BUG_ON(slabs_node(s, offline_node));
4071 s->node[offline_node] = NULL;
4072 kmem_cache_free(kmem_cache_node, n);
4075 mutex_unlock(&slab_mutex);
4078 static int slab_mem_going_online_callback(void *arg)
4080 struct kmem_cache_node *n;
4081 struct kmem_cache *s;
4082 struct memory_notify *marg = arg;
4083 int nid = marg->status_change_nid_normal;
4087 * If the node's memory is already available, then kmem_cache_node is
4088 * already created. Nothing to do.
4094 * We are bringing a node online. No memory is available yet. We must
4095 * allocate a kmem_cache_node structure in order to bring the node
4098 mutex_lock(&slab_mutex);
4099 list_for_each_entry(s, &slab_caches, list) {
4101 * XXX: kmem_cache_alloc_node will fallback to other nodes
4102 * since memory is not yet available from the node that
4105 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4110 init_kmem_cache_node(n);
4114 mutex_unlock(&slab_mutex);
4118 static int slab_memory_callback(struct notifier_block *self,
4119 unsigned long action, void *arg)
4124 case MEM_GOING_ONLINE:
4125 ret = slab_mem_going_online_callback(arg);
4127 case MEM_GOING_OFFLINE:
4128 ret = slab_mem_going_offline_callback(arg);
4131 case MEM_CANCEL_ONLINE:
4132 slab_mem_offline_callback(arg);
4135 case MEM_CANCEL_OFFLINE:
4139 ret = notifier_from_errno(ret);
4145 static struct notifier_block slab_memory_callback_nb = {
4146 .notifier_call = slab_memory_callback,
4147 .priority = SLAB_CALLBACK_PRI,
4150 /********************************************************************
4151 * Basic setup of slabs
4152 *******************************************************************/
4155 * Used for early kmem_cache structures that were allocated using
4156 * the page allocator. Allocate them properly then fix up the pointers
4157 * that may be pointing to the wrong kmem_cache structure.
4160 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4163 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4164 struct kmem_cache_node *n;
4166 memcpy(s, static_cache, kmem_cache->object_size);
4169 * This runs very early, and only the boot processor is supposed to be
4170 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4173 __flush_cpu_slab(s, smp_processor_id());
4174 for_each_kmem_cache_node(s, node, n) {
4177 list_for_each_entry(p, &n->partial, lru)
4180 #ifdef CONFIG_SLUB_DEBUG
4181 list_for_each_entry(p, &n->full, lru)
4185 slab_init_memcg_params(s);
4186 list_add(&s->list, &slab_caches);
4187 memcg_link_cache(s);
4191 void __init kmem_cache_init(void)
4193 static __initdata struct kmem_cache boot_kmem_cache,
4194 boot_kmem_cache_node;
4196 if (debug_guardpage_minorder())
4199 kmem_cache_node = &boot_kmem_cache_node;
4200 kmem_cache = &boot_kmem_cache;
4202 create_boot_cache(kmem_cache_node, "kmem_cache_node",
4203 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
4205 register_hotmemory_notifier(&slab_memory_callback_nb);
4207 /* Able to allocate the per node structures */
4208 slab_state = PARTIAL;
4210 create_boot_cache(kmem_cache, "kmem_cache",
4211 offsetof(struct kmem_cache, node) +
4212 nr_node_ids * sizeof(struct kmem_cache_node *),
4213 SLAB_HWCACHE_ALIGN, 0, 0);
4215 kmem_cache = bootstrap(&boot_kmem_cache);
4218 * Allocate kmem_cache_node properly from the kmem_cache slab.
4219 * kmem_cache_node is separately allocated so no need to
4220 * update any list pointers.
4222 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4224 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4225 setup_kmalloc_cache_index_table();
4226 create_kmalloc_caches(0);
4228 /* Setup random freelists for each cache */
4229 init_freelist_randomization();
4231 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4234 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%u, Nodes=%d\n",
4236 slub_min_order, slub_max_order, slub_min_objects,
4237 nr_cpu_ids, nr_node_ids);
4240 void __init kmem_cache_init_late(void)
4245 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
4246 slab_flags_t flags, void (*ctor)(void *))
4248 struct kmem_cache *s, *c;
4250 s = find_mergeable(size, align, flags, name, ctor);
4255 * Adjust the object sizes so that we clear
4256 * the complete object on kzalloc.
4258 s->object_size = max(s->object_size, size);
4259 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
4261 for_each_memcg_cache(c, s) {
4262 c->object_size = s->object_size;
4263 c->inuse = max(c->inuse, ALIGN(size, sizeof(void *)));
4266 if (sysfs_slab_alias(s, name)) {
4275 int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
4279 err = kmem_cache_open(s, flags);
4283 /* Mutex is not taken during early boot */
4284 if (slab_state <= UP)
4287 memcg_propagate_slab_attrs(s);
4288 err = sysfs_slab_add(s);
4290 __kmem_cache_release(s);
4295 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4297 struct kmem_cache *s;
4300 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4301 return kmalloc_large(size, gfpflags);
4303 s = kmalloc_slab(size, gfpflags);
4305 if (unlikely(ZERO_OR_NULL_PTR(s)))
4308 ret = slab_alloc(s, gfpflags, caller);
4310 /* Honor the call site pointer we received. */
4311 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4317 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4318 int node, unsigned long caller)
4320 struct kmem_cache *s;
4323 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4324 ret = kmalloc_large_node(size, gfpflags, node);
4326 trace_kmalloc_node(caller, ret,
4327 size, PAGE_SIZE << get_order(size),
4333 s = kmalloc_slab(size, gfpflags);
4335 if (unlikely(ZERO_OR_NULL_PTR(s)))
4338 ret = slab_alloc_node(s, gfpflags, node, caller);
4340 /* Honor the call site pointer we received. */
4341 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4348 static int count_inuse(struct page *page)
4353 static int count_total(struct page *page)
4355 return page->objects;
4359 #ifdef CONFIG_SLUB_DEBUG
4360 static int validate_slab(struct kmem_cache *s, struct page *page,
4364 void *addr = page_address(page);
4366 if (!check_slab(s, page) ||
4367 !on_freelist(s, page, NULL))
4370 /* Now we know that a valid freelist exists */
4371 bitmap_zero(map, page->objects);
4373 get_map(s, page, map);
4374 for_each_object(p, s, addr, page->objects) {
4375 if (test_bit(slab_index(p, s, addr), map))
4376 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4380 for_each_object(p, s, addr, page->objects)
4381 if (!test_bit(slab_index(p, s, addr), map))
4382 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4387 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4391 validate_slab(s, page, map);
4395 static int validate_slab_node(struct kmem_cache *s,
4396 struct kmem_cache_node *n, unsigned long *map)
4398 unsigned long count = 0;
4400 unsigned long flags;
4402 spin_lock_irqsave(&n->list_lock, flags);
4404 list_for_each_entry(page, &n->partial, lru) {
4405 validate_slab_slab(s, page, map);
4408 if (count != n->nr_partial)
4409 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4410 s->name, count, n->nr_partial);
4412 if (!(s->flags & SLAB_STORE_USER))
4415 list_for_each_entry(page, &n->full, lru) {
4416 validate_slab_slab(s, page, map);
4419 if (count != atomic_long_read(&n->nr_slabs))
4420 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4421 s->name, count, atomic_long_read(&n->nr_slabs));
4424 spin_unlock_irqrestore(&n->list_lock, flags);
4428 static long validate_slab_cache(struct kmem_cache *s)
4431 unsigned long count = 0;
4432 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4433 sizeof(unsigned long), GFP_KERNEL);
4434 struct kmem_cache_node *n;
4440 for_each_kmem_cache_node(s, node, n)
4441 count += validate_slab_node(s, n, map);
4446 * Generate lists of code addresses where slabcache objects are allocated
4451 unsigned long count;
4458 DECLARE_BITMAP(cpus, NR_CPUS);
4464 unsigned long count;
4465 struct location *loc;
4468 static void free_loc_track(struct loc_track *t)
4471 free_pages((unsigned long)t->loc,
4472 get_order(sizeof(struct location) * t->max));
4475 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4480 order = get_order(sizeof(struct location) * max);
4482 l = (void *)__get_free_pages(flags, order);
4487 memcpy(l, t->loc, sizeof(struct location) * t->count);
4495 static int add_location(struct loc_track *t, struct kmem_cache *s,
4496 const struct track *track)
4498 long start, end, pos;
4500 unsigned long caddr;
4501 unsigned long age = jiffies - track->when;
4507 pos = start + (end - start + 1) / 2;
4510 * There is nothing at "end". If we end up there
4511 * we need to add something to before end.
4516 caddr = t->loc[pos].addr;
4517 if (track->addr == caddr) {
4523 if (age < l->min_time)
4525 if (age > l->max_time)
4528 if (track->pid < l->min_pid)
4529 l->min_pid = track->pid;
4530 if (track->pid > l->max_pid)
4531 l->max_pid = track->pid;
4533 cpumask_set_cpu(track->cpu,
4534 to_cpumask(l->cpus));
4536 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4540 if (track->addr < caddr)
4547 * Not found. Insert new tracking element.
4549 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4555 (t->count - pos) * sizeof(struct location));
4558 l->addr = track->addr;
4562 l->min_pid = track->pid;
4563 l->max_pid = track->pid;
4564 cpumask_clear(to_cpumask(l->cpus));
4565 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4566 nodes_clear(l->nodes);
4567 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4571 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4572 struct page *page, enum track_item alloc,
4575 void *addr = page_address(page);
4578 bitmap_zero(map, page->objects);
4579 get_map(s, page, map);
4581 for_each_object(p, s, addr, page->objects)
4582 if (!test_bit(slab_index(p, s, addr), map))
4583 add_location(t, s, get_track(s, p, alloc));
4586 static int list_locations(struct kmem_cache *s, char *buf,
4587 enum track_item alloc)
4591 struct loc_track t = { 0, 0, NULL };
4593 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4594 sizeof(unsigned long), GFP_KERNEL);
4595 struct kmem_cache_node *n;
4597 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4600 return sprintf(buf, "Out of memory\n");
4602 /* Push back cpu slabs */
4605 for_each_kmem_cache_node(s, node, n) {
4606 unsigned long flags;
4609 if (!atomic_long_read(&n->nr_slabs))
4612 spin_lock_irqsave(&n->list_lock, flags);
4613 list_for_each_entry(page, &n->partial, lru)
4614 process_slab(&t, s, page, alloc, map);
4615 list_for_each_entry(page, &n->full, lru)
4616 process_slab(&t, s, page, alloc, map);
4617 spin_unlock_irqrestore(&n->list_lock, flags);
4620 for (i = 0; i < t.count; i++) {
4621 struct location *l = &t.loc[i];
4623 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4625 len += sprintf(buf + len, "%7ld ", l->count);
4628 len += sprintf(buf + len, "%pS", (void *)l->addr);
4630 len += sprintf(buf + len, "<not-available>");
4632 if (l->sum_time != l->min_time) {
4633 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4635 (long)div_u64(l->sum_time, l->count),
4638 len += sprintf(buf + len, " age=%ld",
4641 if (l->min_pid != l->max_pid)
4642 len += sprintf(buf + len, " pid=%ld-%ld",
4643 l->min_pid, l->max_pid);
4645 len += sprintf(buf + len, " pid=%ld",
4648 if (num_online_cpus() > 1 &&
4649 !cpumask_empty(to_cpumask(l->cpus)) &&
4650 len < PAGE_SIZE - 60)
4651 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4653 cpumask_pr_args(to_cpumask(l->cpus)));
4655 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4656 len < PAGE_SIZE - 60)
4657 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4659 nodemask_pr_args(&l->nodes));
4661 len += sprintf(buf + len, "\n");
4667 len += sprintf(buf, "No data\n");
4672 #ifdef SLUB_RESILIENCY_TEST
4673 static void __init resiliency_test(void)
4677 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4679 pr_err("SLUB resiliency testing\n");
4680 pr_err("-----------------------\n");
4681 pr_err("A. Corruption after allocation\n");
4683 p = kzalloc(16, GFP_KERNEL);
4685 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4688 validate_slab_cache(kmalloc_caches[4]);
4690 /* Hmmm... The next two are dangerous */
4691 p = kzalloc(32, GFP_KERNEL);
4692 p[32 + sizeof(void *)] = 0x34;
4693 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4695 pr_err("If allocated object is overwritten then not detectable\n\n");
4697 validate_slab_cache(kmalloc_caches[5]);
4698 p = kzalloc(64, GFP_KERNEL);
4699 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4701 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4703 pr_err("If allocated object is overwritten then not detectable\n\n");
4704 validate_slab_cache(kmalloc_caches[6]);
4706 pr_err("\nB. Corruption after free\n");
4707 p = kzalloc(128, GFP_KERNEL);
4710 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4711 validate_slab_cache(kmalloc_caches[7]);
4713 p = kzalloc(256, GFP_KERNEL);
4716 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4717 validate_slab_cache(kmalloc_caches[8]);
4719 p = kzalloc(512, GFP_KERNEL);
4722 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4723 validate_slab_cache(kmalloc_caches[9]);
4727 static void resiliency_test(void) {};
4732 enum slab_stat_type {
4733 SL_ALL, /* All slabs */
4734 SL_PARTIAL, /* Only partially allocated slabs */
4735 SL_CPU, /* Only slabs used for cpu caches */
4736 SL_OBJECTS, /* Determine allocated objects not slabs */
4737 SL_TOTAL /* Determine object capacity not slabs */
4740 #define SO_ALL (1 << SL_ALL)
4741 #define SO_PARTIAL (1 << SL_PARTIAL)
4742 #define SO_CPU (1 << SL_CPU)
4743 #define SO_OBJECTS (1 << SL_OBJECTS)
4744 #define SO_TOTAL (1 << SL_TOTAL)
4747 static bool memcg_sysfs_enabled = IS_ENABLED(CONFIG_SLUB_MEMCG_SYSFS_ON);
4749 static int __init setup_slub_memcg_sysfs(char *str)
4753 if (get_option(&str, &v) > 0)
4754 memcg_sysfs_enabled = v;
4759 __setup("slub_memcg_sysfs=", setup_slub_memcg_sysfs);
4762 static ssize_t show_slab_objects(struct kmem_cache *s,
4763 char *buf, unsigned long flags)
4765 unsigned long total = 0;
4768 unsigned long *nodes;
4770 nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4774 if (flags & SO_CPU) {
4777 for_each_possible_cpu(cpu) {
4778 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4783 page = READ_ONCE(c->page);
4787 node = page_to_nid(page);
4788 if (flags & SO_TOTAL)
4790 else if (flags & SO_OBJECTS)
4798 page = slub_percpu_partial_read_once(c);
4800 node = page_to_nid(page);
4801 if (flags & SO_TOTAL)
4803 else if (flags & SO_OBJECTS)
4814 #ifdef CONFIG_SLUB_DEBUG
4815 if (flags & SO_ALL) {
4816 struct kmem_cache_node *n;
4818 for_each_kmem_cache_node(s, node, n) {
4820 if (flags & SO_TOTAL)
4821 x = atomic_long_read(&n->total_objects);
4822 else if (flags & SO_OBJECTS)
4823 x = atomic_long_read(&n->total_objects) -
4824 count_partial(n, count_free);
4826 x = atomic_long_read(&n->nr_slabs);
4833 if (flags & SO_PARTIAL) {
4834 struct kmem_cache_node *n;
4836 for_each_kmem_cache_node(s, node, n) {
4837 if (flags & SO_TOTAL)
4838 x = count_partial(n, count_total);
4839 else if (flags & SO_OBJECTS)
4840 x = count_partial(n, count_inuse);
4847 x = sprintf(buf, "%lu", total);
4849 for (node = 0; node < nr_node_ids; node++)
4851 x += sprintf(buf + x, " N%d=%lu",
4856 return x + sprintf(buf + x, "\n");
4859 #ifdef CONFIG_SLUB_DEBUG
4860 static int any_slab_objects(struct kmem_cache *s)
4863 struct kmem_cache_node *n;
4865 for_each_kmem_cache_node(s, node, n)
4866 if (atomic_long_read(&n->total_objects))
4873 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4874 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4876 struct slab_attribute {
4877 struct attribute attr;
4878 ssize_t (*show)(struct kmem_cache *s, char *buf);
4879 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4882 #define SLAB_ATTR_RO(_name) \
4883 static struct slab_attribute _name##_attr = \
4884 __ATTR(_name, 0400, _name##_show, NULL)
4886 #define SLAB_ATTR(_name) \
4887 static struct slab_attribute _name##_attr = \
4888 __ATTR(_name, 0600, _name##_show, _name##_store)
4890 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4892 return sprintf(buf, "%u\n", s->size);
4894 SLAB_ATTR_RO(slab_size);
4896 static ssize_t align_show(struct kmem_cache *s, char *buf)
4898 return sprintf(buf, "%u\n", s->align);
4900 SLAB_ATTR_RO(align);
4902 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4904 return sprintf(buf, "%u\n", s->object_size);
4906 SLAB_ATTR_RO(object_size);
4908 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4910 return sprintf(buf, "%d\n", oo_objects(s->oo));
4912 SLAB_ATTR_RO(objs_per_slab);
4914 static ssize_t order_store(struct kmem_cache *s,
4915 const char *buf, size_t length)
4917 unsigned long order;
4920 err = kstrtoul(buf, 10, &order);
4924 if (order > slub_max_order || order < slub_min_order)
4927 calculate_sizes(s, order);
4931 static ssize_t order_show(struct kmem_cache *s, char *buf)
4933 return sprintf(buf, "%d\n", oo_order(s->oo));
4937 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4939 return sprintf(buf, "%lu\n", s->min_partial);
4942 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4948 err = kstrtoul(buf, 10, &min);
4952 set_min_partial(s, min);
4955 SLAB_ATTR(min_partial);
4957 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4959 return sprintf(buf, "%u\n", slub_cpu_partial(s));
4962 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4965 unsigned int objects;
4968 err = kstrtouint(buf, 10, &objects);
4971 if (objects && !kmem_cache_has_cpu_partial(s))
4974 slub_set_cpu_partial(s, objects);
4978 SLAB_ATTR(cpu_partial);
4980 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4984 return sprintf(buf, "%pS\n", s->ctor);
4988 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4990 return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
4992 SLAB_ATTR_RO(aliases);
4994 static ssize_t partial_show(struct kmem_cache *s, char *buf)
4996 return show_slab_objects(s, buf, SO_PARTIAL);
4998 SLAB_ATTR_RO(partial);
5000 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5002 return show_slab_objects(s, buf, SO_CPU);
5004 SLAB_ATTR_RO(cpu_slabs);
5006 static ssize_t objects_show(struct kmem_cache *s, char *buf)
5008 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5010 SLAB_ATTR_RO(objects);
5012 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5014 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5016 SLAB_ATTR_RO(objects_partial);
5018 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5025 for_each_online_cpu(cpu) {
5028 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5031 pages += page->pages;
5032 objects += page->pobjects;
5036 len = sprintf(buf, "%d(%d)", objects, pages);
5039 for_each_online_cpu(cpu) {
5042 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5044 if (page && len < PAGE_SIZE - 20)
5045 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
5046 page->pobjects, page->pages);
5049 return len + sprintf(buf + len, "\n");
5051 SLAB_ATTR_RO(slabs_cpu_partial);
5053 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5055 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5058 static ssize_t reclaim_account_store(struct kmem_cache *s,
5059 const char *buf, size_t length)
5061 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
5063 s->flags |= SLAB_RECLAIM_ACCOUNT;
5066 SLAB_ATTR(reclaim_account);
5068 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5070 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5072 SLAB_ATTR_RO(hwcache_align);
5074 #ifdef CONFIG_ZONE_DMA
5075 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5077 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5079 SLAB_ATTR_RO(cache_dma);
5082 static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5084 return sprintf(buf, "%u\n", s->usersize);
5086 SLAB_ATTR_RO(usersize);
5088 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5090 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5092 SLAB_ATTR_RO(destroy_by_rcu);
5094 static ssize_t reserved_show(struct kmem_cache *s, char *buf)
5096 return sprintf(buf, "%u\n", s->reserved);
5098 SLAB_ATTR_RO(reserved);
5100 #ifdef CONFIG_SLUB_DEBUG
5101 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5103 return show_slab_objects(s, buf, SO_ALL);
5105 SLAB_ATTR_RO(slabs);
5107 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5109 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5111 SLAB_ATTR_RO(total_objects);
5113 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5115 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5118 static ssize_t sanity_checks_store(struct kmem_cache *s,
5119 const char *buf, size_t length)
5121 s->flags &= ~SLAB_CONSISTENCY_CHECKS;
5122 if (buf[0] == '1') {
5123 s->flags &= ~__CMPXCHG_DOUBLE;
5124 s->flags |= SLAB_CONSISTENCY_CHECKS;
5128 SLAB_ATTR(sanity_checks);
5130 static ssize_t trace_show(struct kmem_cache *s, char *buf)
5132 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5135 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
5139 * Tracing a merged cache is going to give confusing results
5140 * as well as cause other issues like converting a mergeable
5141 * cache into an umergeable one.
5143 if (s->refcount > 1)
5146 s->flags &= ~SLAB_TRACE;
5147 if (buf[0] == '1') {
5148 s->flags &= ~__CMPXCHG_DOUBLE;
5149 s->flags |= SLAB_TRACE;
5155 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5157 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5160 static ssize_t red_zone_store(struct kmem_cache *s,
5161 const char *buf, size_t length)
5163 if (any_slab_objects(s))
5166 s->flags &= ~SLAB_RED_ZONE;
5167 if (buf[0] == '1') {
5168 s->flags |= SLAB_RED_ZONE;
5170 calculate_sizes(s, -1);
5173 SLAB_ATTR(red_zone);
5175 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5177 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5180 static ssize_t poison_store(struct kmem_cache *s,
5181 const char *buf, size_t length)
5183 if (any_slab_objects(s))
5186 s->flags &= ~SLAB_POISON;
5187 if (buf[0] == '1') {
5188 s->flags |= SLAB_POISON;
5190 calculate_sizes(s, -1);
5195 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5197 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5200 static ssize_t store_user_store(struct kmem_cache *s,
5201 const char *buf, size_t length)
5203 if (any_slab_objects(s))
5206 s->flags &= ~SLAB_STORE_USER;
5207 if (buf[0] == '1') {
5208 s->flags &= ~__CMPXCHG_DOUBLE;
5209 s->flags |= SLAB_STORE_USER;
5211 calculate_sizes(s, -1);
5214 SLAB_ATTR(store_user);
5216 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5221 static ssize_t validate_store(struct kmem_cache *s,
5222 const char *buf, size_t length)
5226 if (buf[0] == '1') {
5227 ret = validate_slab_cache(s);
5233 SLAB_ATTR(validate);
5235 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5237 if (!(s->flags & SLAB_STORE_USER))
5239 return list_locations(s, buf, TRACK_ALLOC);
5241 SLAB_ATTR_RO(alloc_calls);
5243 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5245 if (!(s->flags & SLAB_STORE_USER))
5247 return list_locations(s, buf, TRACK_FREE);
5249 SLAB_ATTR_RO(free_calls);
5250 #endif /* CONFIG_SLUB_DEBUG */
5252 #ifdef CONFIG_FAILSLAB
5253 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5255 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5258 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5261 if (s->refcount > 1)
5264 s->flags &= ~SLAB_FAILSLAB;
5266 s->flags |= SLAB_FAILSLAB;
5269 SLAB_ATTR(failslab);
5272 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5277 static ssize_t shrink_store(struct kmem_cache *s,
5278 const char *buf, size_t length)
5281 kmem_cache_shrink(s);
5289 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5291 return sprintf(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5294 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5295 const char *buf, size_t length)
5300 err = kstrtouint(buf, 10, &ratio);
5306 s->remote_node_defrag_ratio = ratio * 10;
5310 SLAB_ATTR(remote_node_defrag_ratio);
5313 #ifdef CONFIG_SLUB_STATS
5314 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5316 unsigned long sum = 0;
5319 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5324 for_each_online_cpu(cpu) {
5325 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5331 len = sprintf(buf, "%lu", sum);
5334 for_each_online_cpu(cpu) {
5335 if (data[cpu] && len < PAGE_SIZE - 20)
5336 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5340 return len + sprintf(buf + len, "\n");
5343 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5347 for_each_online_cpu(cpu)
5348 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5351 #define STAT_ATTR(si, text) \
5352 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5354 return show_stat(s, buf, si); \
5356 static ssize_t text##_store(struct kmem_cache *s, \
5357 const char *buf, size_t length) \
5359 if (buf[0] != '0') \
5361 clear_stat(s, si); \
5366 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5367 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5368 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5369 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5370 STAT_ATTR(FREE_FROZEN, free_frozen);
5371 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5372 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5373 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5374 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5375 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5376 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5377 STAT_ATTR(FREE_SLAB, free_slab);
5378 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5379 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5380 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5381 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5382 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5383 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5384 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5385 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5386 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5387 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5388 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5389 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5390 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5391 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5394 static struct attribute *slab_attrs[] = {
5395 &slab_size_attr.attr,
5396 &object_size_attr.attr,
5397 &objs_per_slab_attr.attr,
5399 &min_partial_attr.attr,
5400 &cpu_partial_attr.attr,
5402 &objects_partial_attr.attr,
5404 &cpu_slabs_attr.attr,
5408 &hwcache_align_attr.attr,
5409 &reclaim_account_attr.attr,
5410 &destroy_by_rcu_attr.attr,
5412 &reserved_attr.attr,
5413 &slabs_cpu_partial_attr.attr,
5414 #ifdef CONFIG_SLUB_DEBUG
5415 &total_objects_attr.attr,
5417 &sanity_checks_attr.attr,
5419 &red_zone_attr.attr,
5421 &store_user_attr.attr,
5422 &validate_attr.attr,
5423 &alloc_calls_attr.attr,
5424 &free_calls_attr.attr,
5426 #ifdef CONFIG_ZONE_DMA
5427 &cache_dma_attr.attr,
5430 &remote_node_defrag_ratio_attr.attr,
5432 #ifdef CONFIG_SLUB_STATS
5433 &alloc_fastpath_attr.attr,
5434 &alloc_slowpath_attr.attr,
5435 &free_fastpath_attr.attr,
5436 &free_slowpath_attr.attr,
5437 &free_frozen_attr.attr,
5438 &free_add_partial_attr.attr,
5439 &free_remove_partial_attr.attr,
5440 &alloc_from_partial_attr.attr,
5441 &alloc_slab_attr.attr,
5442 &alloc_refill_attr.attr,
5443 &alloc_node_mismatch_attr.attr,
5444 &free_slab_attr.attr,
5445 &cpuslab_flush_attr.attr,
5446 &deactivate_full_attr.attr,
5447 &deactivate_empty_attr.attr,
5448 &deactivate_to_head_attr.attr,
5449 &deactivate_to_tail_attr.attr,
5450 &deactivate_remote_frees_attr.attr,
5451 &deactivate_bypass_attr.attr,
5452 &order_fallback_attr.attr,
5453 &cmpxchg_double_fail_attr.attr,
5454 &cmpxchg_double_cpu_fail_attr.attr,
5455 &cpu_partial_alloc_attr.attr,
5456 &cpu_partial_free_attr.attr,
5457 &cpu_partial_node_attr.attr,
5458 &cpu_partial_drain_attr.attr,
5460 #ifdef CONFIG_FAILSLAB
5461 &failslab_attr.attr,
5463 &usersize_attr.attr,
5468 static const struct attribute_group slab_attr_group = {
5469 .attrs = slab_attrs,
5472 static ssize_t slab_attr_show(struct kobject *kobj,
5473 struct attribute *attr,
5476 struct slab_attribute *attribute;
5477 struct kmem_cache *s;
5480 attribute = to_slab_attr(attr);
5483 if (!attribute->show)
5486 err = attribute->show(s, buf);
5491 static ssize_t slab_attr_store(struct kobject *kobj,
5492 struct attribute *attr,
5493 const char *buf, size_t len)
5495 struct slab_attribute *attribute;
5496 struct kmem_cache *s;
5499 attribute = to_slab_attr(attr);
5502 if (!attribute->store)
5505 err = attribute->store(s, buf, len);
5507 if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5508 struct kmem_cache *c;
5510 mutex_lock(&slab_mutex);
5511 if (s->max_attr_size < len)
5512 s->max_attr_size = len;
5515 * This is a best effort propagation, so this function's return
5516 * value will be determined by the parent cache only. This is
5517 * basically because not all attributes will have a well
5518 * defined semantics for rollbacks - most of the actions will
5519 * have permanent effects.
5521 * Returning the error value of any of the children that fail
5522 * is not 100 % defined, in the sense that users seeing the
5523 * error code won't be able to know anything about the state of
5526 * Only returning the error code for the parent cache at least
5527 * has well defined semantics. The cache being written to
5528 * directly either failed or succeeded, in which case we loop
5529 * through the descendants with best-effort propagation.
5531 for_each_memcg_cache(c, s)
5532 attribute->store(c, buf, len);
5533 mutex_unlock(&slab_mutex);
5539 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5543 char *buffer = NULL;
5544 struct kmem_cache *root_cache;
5546 if (is_root_cache(s))
5549 root_cache = s->memcg_params.root_cache;
5552 * This mean this cache had no attribute written. Therefore, no point
5553 * in copying default values around
5555 if (!root_cache->max_attr_size)
5558 for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5561 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5564 if (!attr || !attr->store || !attr->show)
5568 * It is really bad that we have to allocate here, so we will
5569 * do it only as a fallback. If we actually allocate, though,
5570 * we can just use the allocated buffer until the end.
5572 * Most of the slub attributes will tend to be very small in
5573 * size, but sysfs allows buffers up to a page, so they can
5574 * theoretically happen.
5578 else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5581 buffer = (char *) get_zeroed_page(GFP_KERNEL);
5582 if (WARN_ON(!buffer))
5587 len = attr->show(root_cache, buf);
5589 attr->store(s, buf, len);
5593 free_page((unsigned long)buffer);
5597 static void kmem_cache_release(struct kobject *k)
5599 slab_kmem_cache_release(to_slab(k));
5602 static const struct sysfs_ops slab_sysfs_ops = {
5603 .show = slab_attr_show,
5604 .store = slab_attr_store,
5607 static struct kobj_type slab_ktype = {
5608 .sysfs_ops = &slab_sysfs_ops,
5609 .release = kmem_cache_release,
5612 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5614 struct kobj_type *ktype = get_ktype(kobj);
5616 if (ktype == &slab_ktype)
5621 static const struct kset_uevent_ops slab_uevent_ops = {
5622 .filter = uevent_filter,
5625 static struct kset *slab_kset;
5627 static inline struct kset *cache_kset(struct kmem_cache *s)
5630 if (!is_root_cache(s))
5631 return s->memcg_params.root_cache->memcg_kset;
5636 #define ID_STR_LENGTH 64
5638 /* Create a unique string id for a slab cache:
5640 * Format :[flags-]size
5642 static char *create_unique_id(struct kmem_cache *s)
5644 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5651 * First flags affecting slabcache operations. We will only
5652 * get here for aliasable slabs so we do not need to support
5653 * too many flags. The flags here must cover all flags that
5654 * are matched during merging to guarantee that the id is
5657 if (s->flags & SLAB_CACHE_DMA)
5659 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5661 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5663 if (s->flags & SLAB_ACCOUNT)
5667 p += sprintf(p, "%07u", s->size);
5669 BUG_ON(p > name + ID_STR_LENGTH - 1);
5673 static void sysfs_slab_remove_workfn(struct work_struct *work)
5675 struct kmem_cache *s =
5676 container_of(work, struct kmem_cache, kobj_remove_work);
5678 if (!s->kobj.state_in_sysfs)
5680 * For a memcg cache, this may be called during
5681 * deactivation and again on shutdown. Remove only once.
5682 * A cache is never shut down before deactivation is
5683 * complete, so no need to worry about synchronization.
5688 kset_unregister(s->memcg_kset);
5690 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5691 kobject_del(&s->kobj);
5693 kobject_put(&s->kobj);
5696 static int sysfs_slab_add(struct kmem_cache *s)
5700 struct kset *kset = cache_kset(s);
5701 int unmergeable = slab_unmergeable(s);
5703 INIT_WORK(&s->kobj_remove_work, sysfs_slab_remove_workfn);
5706 kobject_init(&s->kobj, &slab_ktype);
5710 if (!unmergeable && disable_higher_order_debug &&
5711 (slub_debug & DEBUG_METADATA_FLAGS))
5716 * Slabcache can never be merged so we can use the name proper.
5717 * This is typically the case for debug situations. In that
5718 * case we can catch duplicate names easily.
5720 sysfs_remove_link(&slab_kset->kobj, s->name);
5724 * Create a unique name for the slab as a target
5727 name = create_unique_id(s);
5730 s->kobj.kset = kset;
5731 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5735 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5740 if (is_root_cache(s) && memcg_sysfs_enabled) {
5741 s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5742 if (!s->memcg_kset) {
5749 kobject_uevent(&s->kobj, KOBJ_ADD);
5751 /* Setup first alias */
5752 sysfs_slab_alias(s, s->name);
5759 kobject_del(&s->kobj);
5763 static void sysfs_slab_remove(struct kmem_cache *s)
5765 if (slab_state < FULL)
5767 * Sysfs has not been setup yet so no need to remove the
5772 kobject_get(&s->kobj);
5773 schedule_work(&s->kobj_remove_work);
5776 void sysfs_slab_release(struct kmem_cache *s)
5778 if (slab_state >= FULL)
5779 kobject_put(&s->kobj);
5783 * Need to buffer aliases during bootup until sysfs becomes
5784 * available lest we lose that information.
5786 struct saved_alias {
5787 struct kmem_cache *s;
5789 struct saved_alias *next;
5792 static struct saved_alias *alias_list;
5794 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5796 struct saved_alias *al;
5798 if (slab_state == FULL) {
5800 * If we have a leftover link then remove it.
5802 sysfs_remove_link(&slab_kset->kobj, name);
5803 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5806 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5812 al->next = alias_list;
5817 static int __init slab_sysfs_init(void)
5819 struct kmem_cache *s;
5822 mutex_lock(&slab_mutex);
5824 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5826 mutex_unlock(&slab_mutex);
5827 pr_err("Cannot register slab subsystem.\n");
5833 list_for_each_entry(s, &slab_caches, list) {
5834 err = sysfs_slab_add(s);
5836 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5840 while (alias_list) {
5841 struct saved_alias *al = alias_list;
5843 alias_list = alias_list->next;
5844 err = sysfs_slab_alias(al->s, al->name);
5846 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5851 mutex_unlock(&slab_mutex);
5856 __initcall(slab_sysfs_init);
5857 #endif /* CONFIG_SYSFS */
5860 * The /proc/slabinfo ABI
5862 #ifdef CONFIG_SLUB_DEBUG
5863 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5865 unsigned long nr_slabs = 0;
5866 unsigned long nr_objs = 0;
5867 unsigned long nr_free = 0;
5869 struct kmem_cache_node *n;
5871 for_each_kmem_cache_node(s, node, n) {
5872 nr_slabs += node_nr_slabs(n);
5873 nr_objs += node_nr_objs(n);
5874 nr_free += count_partial(n, count_free);
5877 sinfo->active_objs = nr_objs - nr_free;
5878 sinfo->num_objs = nr_objs;
5879 sinfo->active_slabs = nr_slabs;
5880 sinfo->num_slabs = nr_slabs;
5881 sinfo->objects_per_slab = oo_objects(s->oo);
5882 sinfo->cache_order = oo_order(s->oo);
5885 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5889 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5890 size_t count, loff_t *ppos)
5894 #endif /* CONFIG_SLUB_DEBUG */