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1/*
2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
4 *
5 * The allocator synchronizes using per slab locks or atomic operatios
6 * and only uses a centralized lock to manage a pool of partial slabs.
7 *
8 * (C) 2007 SGI, Christoph Lameter
9 * (C) 2011 Linux Foundation, Christoph Lameter
10 */
11
12#include <linux/mm.h>
13#include <linux/swap.h> /* struct reclaim_state */
14#include <linux/module.h>
15#include <linux/bit_spinlock.h>
16#include <linux/interrupt.h>
17#include <linux/bitops.h>
18#include <linux/slab.h>
19#include "slab.h"
20#include <linux/proc_fs.h>
21#include <linux/notifier.h>
22#include <linux/seq_file.h>
23#include <linux/kasan.h>
24#include <linux/kmemcheck.h>
25#include <linux/cpu.h>
26#include <linux/cpuset.h>
27#include <linux/mempolicy.h>
28#include <linux/ctype.h>
29#include <linux/debugobjects.h>
30#include <linux/kallsyms.h>
31#include <linux/memory.h>
32#include <linux/math64.h>
33#include <linux/fault-inject.h>
34#include <linux/stacktrace.h>
35#include <linux/prefetch.h>
36#include <linux/memcontrol.h>
37
38#include <trace/events/kmem.h>
39
40#include "internal.h"
41
42/*
43 * Lock order:
44 * 1. slab_mutex (Global Mutex)
45 * 2. node->list_lock
46 * 3. slab_lock(page) (Only on some arches and for debugging)
47 *
48 * slab_mutex
49 *
50 * The role of the slab_mutex is to protect the list of all the slabs
51 * and to synchronize major metadata changes to slab cache structures.
52 *
53 * The slab_lock is only used for debugging and on arches that do not
54 * have the ability to do a cmpxchg_double. It only protects the second
55 * double word in the page struct. Meaning
56 * A. page->freelist -> List of object free in a page
57 * B. page->counters -> Counters of objects
58 * C. page->frozen -> frozen state
59 *
60 * If a slab is frozen then it is exempt from list management. It is not
61 * on any list. The processor that froze the slab is the one who can
62 * perform list operations on the page. Other processors may put objects
63 * onto the freelist but the processor that froze the slab is the only
64 * one that can retrieve the objects from the page's freelist.
65 *
66 * The list_lock protects the partial and full list on each node and
67 * the partial slab counter. If taken then no new slabs may be added or
68 * removed from the lists nor make the number of partial slabs be modified.
69 * (Note that the total number of slabs is an atomic value that may be
70 * modified without taking the list lock).
71 *
72 * The list_lock is a centralized lock and thus we avoid taking it as
73 * much as possible. As long as SLUB does not have to handle partial
74 * slabs, operations can continue without any centralized lock. F.e.
75 * allocating a long series of objects that fill up slabs does not require
76 * the list lock.
77 * Interrupts are disabled during allocation and deallocation in order to
78 * make the slab allocator safe to use in the context of an irq. In addition
79 * interrupts are disabled to ensure that the processor does not change
80 * while handling per_cpu slabs, due to kernel preemption.
81 *
82 * SLUB assigns one slab for allocation to each processor.
83 * Allocations only occur from these slabs called cpu slabs.
84 *
85 * Slabs with free elements are kept on a partial list and during regular
86 * operations no list for full slabs is used. If an object in a full slab is
87 * freed then the slab will show up again on the partial lists.
88 * We track full slabs for debugging purposes though because otherwise we
89 * cannot scan all objects.
90 *
91 * Slabs are freed when they become empty. Teardown and setup is
92 * minimal so we rely on the page allocators per cpu caches for
93 * fast frees and allocs.
94 *
95 * Overloading of page flags that are otherwise used for LRU management.
96 *
97 * PageActive The slab is frozen and exempt from list processing.
98 * This means that the slab is dedicated to a purpose
99 * such as satisfying allocations for a specific
100 * processor. Objects may be freed in the slab while
101 * it is frozen but slab_free will then skip the usual
102 * list operations. It is up to the processor holding
103 * the slab to integrate the slab into the slab lists
104 * when the slab is no longer needed.
105 *
106 * One use of this flag is to mark slabs that are
107 * used for allocations. Then such a slab becomes a cpu
108 * slab. The cpu slab may be equipped with an additional
109 * freelist that allows lockless access to
110 * free objects in addition to the regular freelist
111 * that requires the slab lock.
112 *
113 * PageError Slab requires special handling due to debug
114 * options set. This moves slab handling out of
115 * the fast path and disables lockless freelists.
116 */
117
118static inline int kmem_cache_debug(struct kmem_cache *s)
119{
120#ifdef CONFIG_SLUB_DEBUG
121 return unlikely(s->flags & SLAB_DEBUG_FLAGS);
122#else
123 return 0;
124#endif
125}
126
127static inline void *fixup_red_left(struct kmem_cache *s, void *p)
128{
129 if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)
130 p += s->red_left_pad;
131
132 return p;
133}
134
135static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
136{
137#ifdef CONFIG_SLUB_CPU_PARTIAL
138 return !kmem_cache_debug(s);
139#else
140 return false;
141#endif
142}
143
144/*
145 * Issues still to be resolved:
146 *
147 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
148 *
149 * - Variable sizing of the per node arrays
150 */
151
152/* Enable to test recovery from slab corruption on boot */
153#undef SLUB_RESILIENCY_TEST
154
155/* Enable to log cmpxchg failures */
156#undef SLUB_DEBUG_CMPXCHG
157
158/*
159 * Mininum number of partial slabs. These will be left on the partial
160 * lists even if they are empty. kmem_cache_shrink may reclaim them.
161 */
162#define MIN_PARTIAL 5
163
164/*
165 * Maximum number of desirable partial slabs.
166 * The existence of more partial slabs makes kmem_cache_shrink
167 * sort the partial list by the number of objects in use.
168 */
169#define MAX_PARTIAL 10
170
171#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
172 SLAB_POISON | SLAB_STORE_USER)
173
174/*
175 * These debug flags cannot use CMPXCHG because there might be consistency
176 * issues when checking or reading debug information
177 */
178#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
179 SLAB_TRACE)
180
181
182/*
183 * Debugging flags that require metadata to be stored in the slab. These get
184 * disabled when slub_debug=O is used and a cache's min order increases with
185 * metadata.
186 */
187#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
188
189#define OO_SHIFT 16
190#define OO_MASK ((1 << OO_SHIFT) - 1)
191#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
192
193/* Internal SLUB flags */
194#define __OBJECT_POISON 0x80000000UL /* Poison object */
195#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
196
197#ifdef CONFIG_SMP
198static struct notifier_block slab_notifier;
199#endif
200
201/*
202 * Tracking user of a slab.
203 */
204#define TRACK_ADDRS_COUNT 16
205struct track {
206 unsigned long addr; /* Called from address */
207#ifdef CONFIG_STACKTRACE
208 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
209#endif
210 int cpu; /* Was running on cpu */
211 int pid; /* Pid context */
212 unsigned long when; /* When did the operation occur */
213};
214
215enum track_item { TRACK_ALLOC, TRACK_FREE };
216
217#ifdef CONFIG_SYSFS
218static int sysfs_slab_add(struct kmem_cache *);
219static int sysfs_slab_alias(struct kmem_cache *, const char *);
220static void memcg_propagate_slab_attrs(struct kmem_cache *s);
221#else
222static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
223static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
224 { return 0; }
225static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
226#endif
227
228static inline void stat(const struct kmem_cache *s, enum stat_item si)
229{
230#ifdef CONFIG_SLUB_STATS
231 /*
232 * The rmw is racy on a preemptible kernel but this is acceptable, so
233 * avoid this_cpu_add()'s irq-disable overhead.
234 */
235 raw_cpu_inc(s->cpu_slab->stat[si]);
236#endif
237}
238
239/********************************************************************
240 * Core slab cache functions
241 *******************************************************************/
242
243static inline void *get_freepointer(struct kmem_cache *s, void *object)
244{
245 return *(void **)(object + s->offset);
246}
247
248static void prefetch_freepointer(const struct kmem_cache *s, void *object)
249{
250 prefetch(object + s->offset);
251}
252
253static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
254{
255 void *p;
256
257 if (!debug_pagealloc_enabled())
258 return get_freepointer(s, object);
259
260 probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
261 return p;
262}
263
264static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
265{
266 *(void **)(object + s->offset) = fp;
267}
268
269/* Loop over all objects in a slab */
270#define for_each_object(__p, __s, __addr, __objects) \
271 for (__p = fixup_red_left(__s, __addr); \
272 __p < (__addr) + (__objects) * (__s)->size; \
273 __p += (__s)->size)
274
275#define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
276 for (__p = fixup_red_left(__s, __addr), __idx = 1; \
277 __idx <= __objects; \
278 __p += (__s)->size, __idx++)
279
280/* Determine object index from a given position */
281static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
282{
283 return (p - addr) / s->size;
284}
285
286static inline int order_objects(int order, unsigned long size, int reserved)
287{
288 return ((PAGE_SIZE << order) - reserved) / size;
289}
290
291static inline struct kmem_cache_order_objects oo_make(int order,
292 unsigned long size, int reserved)
293{
294 struct kmem_cache_order_objects x = {
295 (order << OO_SHIFT) + order_objects(order, size, reserved)
296 };
297
298 return x;
299}
300
301static inline int oo_order(struct kmem_cache_order_objects x)
302{
303 return x.x >> OO_SHIFT;
304}
305
306static inline int oo_objects(struct kmem_cache_order_objects x)
307{
308 return x.x & OO_MASK;
309}
310
311/*
312 * Per slab locking using the pagelock
313 */
314static __always_inline void slab_lock(struct page *page)
315{
316 VM_BUG_ON_PAGE(PageTail(page), page);
317 bit_spin_lock(PG_locked, &page->flags);
318}
319
320static __always_inline void slab_unlock(struct page *page)
321{
322 VM_BUG_ON_PAGE(PageTail(page), page);
323 __bit_spin_unlock(PG_locked, &page->flags);
324}
325
326static inline void set_page_slub_counters(struct page *page, unsigned long counters_new)
327{
328 struct page tmp;
329 tmp.counters = counters_new;
330 /*
331 * page->counters can cover frozen/inuse/objects as well
332 * as page->_count. If we assign to ->counters directly
333 * we run the risk of losing updates to page->_count, so
334 * be careful and only assign to the fields we need.
335 */
336 page->frozen = tmp.frozen;
337 page->inuse = tmp.inuse;
338 page->objects = tmp.objects;
339}
340
341/* Interrupts must be disabled (for the fallback code to work right) */
342static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
343 void *freelist_old, unsigned long counters_old,
344 void *freelist_new, unsigned long counters_new,
345 const char *n)
346{
347 VM_BUG_ON(!irqs_disabled());
348#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
349 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
350 if (s->flags & __CMPXCHG_DOUBLE) {
351 if (cmpxchg_double(&page->freelist, &page->counters,
352 freelist_old, counters_old,
353 freelist_new, counters_new))
354 return true;
355 } else
356#endif
357 {
358 slab_lock(page);
359 if (page->freelist == freelist_old &&
360 page->counters == counters_old) {
361 page->freelist = freelist_new;
362 set_page_slub_counters(page, counters_new);
363 slab_unlock(page);
364 return true;
365 }
366 slab_unlock(page);
367 }
368
369 cpu_relax();
370 stat(s, CMPXCHG_DOUBLE_FAIL);
371
372#ifdef SLUB_DEBUG_CMPXCHG
373 pr_info("%s %s: cmpxchg double redo ", n, s->name);
374#endif
375
376 return false;
377}
378
379static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
380 void *freelist_old, unsigned long counters_old,
381 void *freelist_new, unsigned long counters_new,
382 const char *n)
383{
384#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
385 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
386 if (s->flags & __CMPXCHG_DOUBLE) {
387 if (cmpxchg_double(&page->freelist, &page->counters,
388 freelist_old, counters_old,
389 freelist_new, counters_new))
390 return true;
391 } else
392#endif
393 {
394 unsigned long flags;
395
396 local_irq_save(flags);
397 slab_lock(page);
398 if (page->freelist == freelist_old &&
399 page->counters == counters_old) {
400 page->freelist = freelist_new;
401 set_page_slub_counters(page, counters_new);
402 slab_unlock(page);
403 local_irq_restore(flags);
404 return true;
405 }
406 slab_unlock(page);
407 local_irq_restore(flags);
408 }
409
410 cpu_relax();
411 stat(s, CMPXCHG_DOUBLE_FAIL);
412
413#ifdef SLUB_DEBUG_CMPXCHG
414 pr_info("%s %s: cmpxchg double redo ", n, s->name);
415#endif
416
417 return false;
418}
419
420#ifdef CONFIG_SLUB_DEBUG
421/*
422 * Determine a map of object in use on a page.
423 *
424 * Node listlock must be held to guarantee that the page does
425 * not vanish from under us.
426 */
427static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
428{
429 void *p;
430 void *addr = page_address(page);
431
432 for (p = page->freelist; p; p = get_freepointer(s, p))
433 set_bit(slab_index(p, s, addr), map);
434}
435
436static inline int size_from_object(struct kmem_cache *s)
437{
438 if (s->flags & SLAB_RED_ZONE)
439 return s->size - s->red_left_pad;
440
441 return s->size;
442}
443
444static inline void *restore_red_left(struct kmem_cache *s, void *p)
445{
446 if (s->flags & SLAB_RED_ZONE)
447 p -= s->red_left_pad;
448
449 return p;
450}
451
452/*
453 * Debug settings:
454 */
455#if defined(CONFIG_SLUB_DEBUG_ON)
456static int slub_debug = DEBUG_DEFAULT_FLAGS;
457#elif defined(CONFIG_KASAN)
458static int slub_debug = SLAB_STORE_USER;
459#else
460static int slub_debug;
461#endif
462
463static char *slub_debug_slabs;
464static int disable_higher_order_debug;
465
466/*
467 * slub is about to manipulate internal object metadata. This memory lies
468 * outside the range of the allocated object, so accessing it would normally
469 * be reported by kasan as a bounds error. metadata_access_enable() is used
470 * to tell kasan that these accesses are OK.
471 */
472static inline void metadata_access_enable(void)
473{
474 kasan_disable_current();
475}
476
477static inline void metadata_access_disable(void)
478{
479 kasan_enable_current();
480}
481
482/*
483 * Object debugging
484 */
485
486/* Verify that a pointer has an address that is valid within a slab page */
487static inline int check_valid_pointer(struct kmem_cache *s,
488 struct page *page, void *object)
489{
490 void *base;
491
492 if (!object)
493 return 1;
494
495 base = page_address(page);
496 object = restore_red_left(s, object);
497 if (object < base || object >= base + page->objects * s->size ||
498 (object - base) % s->size) {
499 return 0;
500 }
501
502 return 1;
503}
504
505static void print_section(char *text, u8 *addr, unsigned int length)
506{
507 metadata_access_enable();
508 print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
509 length, 1);
510 metadata_access_disable();
511}
512
513static struct track *get_track(struct kmem_cache *s, void *object,
514 enum track_item alloc)
515{
516 struct track *p;
517
518 if (s->offset)
519 p = object + s->offset + sizeof(void *);
520 else
521 p = object + s->inuse;
522
523 return p + alloc;
524}
525
526static void set_track(struct kmem_cache *s, void *object,
527 enum track_item alloc, unsigned long addr)
528{
529 struct track *p = get_track(s, object, alloc);
530
531 if (addr) {
532#ifdef CONFIG_STACKTRACE
533 struct stack_trace trace;
534 int i;
535
536 trace.nr_entries = 0;
537 trace.max_entries = TRACK_ADDRS_COUNT;
538 trace.entries = p->addrs;
539 trace.skip = 3;
540 metadata_access_enable();
541 save_stack_trace(&trace);
542 metadata_access_disable();
543
544 /* See rant in lockdep.c */
545 if (trace.nr_entries != 0 &&
546 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
547 trace.nr_entries--;
548
549 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
550 p->addrs[i] = 0;
551#endif
552 p->addr = addr;
553 p->cpu = smp_processor_id();
554 p->pid = current->pid;
555 p->when = jiffies;
556 } else
557 memset(p, 0, sizeof(struct track));
558}
559
560static void init_tracking(struct kmem_cache *s, void *object)
561{
562 if (!(s->flags & SLAB_STORE_USER))
563 return;
564
565 set_track(s, object, TRACK_FREE, 0UL);
566 set_track(s, object, TRACK_ALLOC, 0UL);
567}
568
569static void print_track(const char *s, struct track *t)
570{
571 if (!t->addr)
572 return;
573
574 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
575 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
576#ifdef CONFIG_STACKTRACE
577 {
578 int i;
579 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
580 if (t->addrs[i])
581 pr_err("\t%pS\n", (void *)t->addrs[i]);
582 else
583 break;
584 }
585#endif
586}
587
588static void print_tracking(struct kmem_cache *s, void *object)
589{
590 if (!(s->flags & SLAB_STORE_USER))
591 return;
592
593 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
594 print_track("Freed", get_track(s, object, TRACK_FREE));
595}
596
597static void print_page_info(struct page *page)
598{
599 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
600 page, page->objects, page->inuse, page->freelist, page->flags);
601
602}
603
604static void slab_bug(struct kmem_cache *s, char *fmt, ...)
605{
606 struct va_format vaf;
607 va_list args;
608
609 va_start(args, fmt);
610 vaf.fmt = fmt;
611 vaf.va = &args;
612 pr_err("=============================================================================\n");
613 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
614 pr_err("-----------------------------------------------------------------------------\n\n");
615
616 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
617 va_end(args);
618}
619
620static void slab_fix(struct kmem_cache *s, char *fmt, ...)
621{
622 struct va_format vaf;
623 va_list args;
624
625 va_start(args, fmt);
626 vaf.fmt = fmt;
627 vaf.va = &args;
628 pr_err("FIX %s: %pV\n", s->name, &vaf);
629 va_end(args);
630}
631
632static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
633{
634 unsigned int off; /* Offset of last byte */
635 u8 *addr = page_address(page);
636
637 print_tracking(s, p);
638
639 print_page_info(page);
640
641 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
642 p, p - addr, get_freepointer(s, p));
643
644 if (s->flags & SLAB_RED_ZONE)
645 print_section("Redzone ", p - s->red_left_pad, s->red_left_pad);
646 else if (p > addr + 16)
647 print_section("Bytes b4 ", p - 16, 16);
648
649 print_section("Object ", p, min_t(unsigned long, s->object_size,
650 PAGE_SIZE));
651 if (s->flags & SLAB_RED_ZONE)
652 print_section("Redzone ", p + s->object_size,
653 s->inuse - s->object_size);
654
655 if (s->offset)
656 off = s->offset + sizeof(void *);
657 else
658 off = s->inuse;
659
660 if (s->flags & SLAB_STORE_USER)
661 off += 2 * sizeof(struct track);
662
663 if (off != size_from_object(s))
664 /* Beginning of the filler is the free pointer */
665 print_section("Padding ", p + off, size_from_object(s) - off);
666
667 dump_stack();
668}
669
670void object_err(struct kmem_cache *s, struct page *page,
671 u8 *object, char *reason)
672{
673 slab_bug(s, "%s", reason);
674 print_trailer(s, page, object);
675}
676
677static void slab_err(struct kmem_cache *s, struct page *page,
678 const char *fmt, ...)
679{
680 va_list args;
681 char buf[100];
682
683 va_start(args, fmt);
684 vsnprintf(buf, sizeof(buf), fmt, args);
685 va_end(args);
686 slab_bug(s, "%s", buf);
687 print_page_info(page);
688 dump_stack();
689}
690
691static void init_object(struct kmem_cache *s, void *object, u8 val)
692{
693 u8 *p = object;
694
695 if (s->flags & SLAB_RED_ZONE)
696 memset(p - s->red_left_pad, val, s->red_left_pad);
697
698 if (s->flags & __OBJECT_POISON) {
699 memset(p, POISON_FREE, s->object_size - 1);
700 p[s->object_size - 1] = POISON_END;
701 }
702
703 if (s->flags & SLAB_RED_ZONE)
704 memset(p + s->object_size, val, s->inuse - s->object_size);
705}
706
707static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
708 void *from, void *to)
709{
710 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
711 memset(from, data, to - from);
712}
713
714static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
715 u8 *object, char *what,
716 u8 *start, unsigned int value, unsigned int bytes)
717{
718 u8 *fault;
719 u8 *end;
720
721 metadata_access_enable();
722 fault = memchr_inv(start, value, bytes);
723 metadata_access_disable();
724 if (!fault)
725 return 1;
726
727 end = start + bytes;
728 while (end > fault && end[-1] == value)
729 end--;
730
731 slab_bug(s, "%s overwritten", what);
732 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
733 fault, end - 1, fault[0], value);
734 print_trailer(s, page, object);
735
736 restore_bytes(s, what, value, fault, end);
737 return 0;
738}
739
740/*
741 * Object layout:
742 *
743 * object address
744 * Bytes of the object to be managed.
745 * If the freepointer may overlay the object then the free
746 * pointer is the first word of the object.
747 *
748 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
749 * 0xa5 (POISON_END)
750 *
751 * object + s->object_size
752 * Padding to reach word boundary. This is also used for Redzoning.
753 * Padding is extended by another word if Redzoning is enabled and
754 * object_size == inuse.
755 *
756 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
757 * 0xcc (RED_ACTIVE) for objects in use.
758 *
759 * object + s->inuse
760 * Meta data starts here.
761 *
762 * A. Free pointer (if we cannot overwrite object on free)
763 * B. Tracking data for SLAB_STORE_USER
764 * C. Padding to reach required alignment boundary or at mininum
765 * one word if debugging is on to be able to detect writes
766 * before the word boundary.
767 *
768 * Padding is done using 0x5a (POISON_INUSE)
769 *
770 * object + s->size
771 * Nothing is used beyond s->size.
772 *
773 * If slabcaches are merged then the object_size and inuse boundaries are mostly
774 * ignored. And therefore no slab options that rely on these boundaries
775 * may be used with merged slabcaches.
776 */
777
778static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
779{
780 unsigned long off = s->inuse; /* The end of info */
781
782 if (s->offset)
783 /* Freepointer is placed after the object. */
784 off += sizeof(void *);
785
786 if (s->flags & SLAB_STORE_USER)
787 /* We also have user information there */
788 off += 2 * sizeof(struct track);
789
790 if (size_from_object(s) == off)
791 return 1;
792
793 return check_bytes_and_report(s, page, p, "Object padding",
794 p + off, POISON_INUSE, size_from_object(s) - off);
795}
796
797/* Check the pad bytes at the end of a slab page */
798static int slab_pad_check(struct kmem_cache *s, struct page *page)
799{
800 u8 *start;
801 u8 *fault;
802 u8 *end;
803 int length;
804 int remainder;
805
806 if (!(s->flags & SLAB_POISON))
807 return 1;
808
809 start = page_address(page);
810 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
811 end = start + length;
812 remainder = length % s->size;
813 if (!remainder)
814 return 1;
815
816 metadata_access_enable();
817 fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
818 metadata_access_disable();
819 if (!fault)
820 return 1;
821 while (end > fault && end[-1] == POISON_INUSE)
822 end--;
823
824 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
825 print_section("Padding ", end - remainder, remainder);
826
827 restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
828 return 0;
829}
830
831static int check_object(struct kmem_cache *s, struct page *page,
832 void *object, u8 val)
833{
834 u8 *p = object;
835 u8 *endobject = object + s->object_size;
836
837 if (s->flags & SLAB_RED_ZONE) {
838 if (!check_bytes_and_report(s, page, object, "Redzone",
839 object - s->red_left_pad, val, s->red_left_pad))
840 return 0;
841
842 if (!check_bytes_and_report(s, page, object, "Redzone",
843 endobject, val, s->inuse - s->object_size))
844 return 0;
845 } else {
846 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
847 check_bytes_and_report(s, page, p, "Alignment padding",
848 endobject, POISON_INUSE,
849 s->inuse - s->object_size);
850 }
851 }
852
853 if (s->flags & SLAB_POISON) {
854 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
855 (!check_bytes_and_report(s, page, p, "Poison", p,
856 POISON_FREE, s->object_size - 1) ||
857 !check_bytes_and_report(s, page, p, "Poison",
858 p + s->object_size - 1, POISON_END, 1)))
859 return 0;
860 /*
861 * check_pad_bytes cleans up on its own.
862 */
863 check_pad_bytes(s, page, p);
864 }
865
866 if (!s->offset && val == SLUB_RED_ACTIVE)
867 /*
868 * Object and freepointer overlap. Cannot check
869 * freepointer while object is allocated.
870 */
871 return 1;
872
873 /* Check free pointer validity */
874 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
875 object_err(s, page, p, "Freepointer corrupt");
876 /*
877 * No choice but to zap it and thus lose the remainder
878 * of the free objects in this slab. May cause
879 * another error because the object count is now wrong.
880 */
881 set_freepointer(s, p, NULL);
882 return 0;
883 }
884 return 1;
885}
886
887static int check_slab(struct kmem_cache *s, struct page *page)
888{
889 int maxobj;
890
891 VM_BUG_ON(!irqs_disabled());
892
893 if (!PageSlab(page)) {
894 slab_err(s, page, "Not a valid slab page");
895 return 0;
896 }
897
898 maxobj = order_objects(compound_order(page), s->size, s->reserved);
899 if (page->objects > maxobj) {
900 slab_err(s, page, "objects %u > max %u",
901 page->objects, maxobj);
902 return 0;
903 }
904 if (page->inuse > page->objects) {
905 slab_err(s, page, "inuse %u > max %u",
906 page->inuse, page->objects);
907 return 0;
908 }
909 /* Slab_pad_check fixes things up after itself */
910 slab_pad_check(s, page);
911 return 1;
912}
913
914/*
915 * Determine if a certain object on a page is on the freelist. Must hold the
916 * slab lock to guarantee that the chains are in a consistent state.
917 */
918static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
919{
920 int nr = 0;
921 void *fp;
922 void *object = NULL;
923 int max_objects;
924
925 fp = page->freelist;
926 while (fp && nr <= page->objects) {
927 if (fp == search)
928 return 1;
929 if (!check_valid_pointer(s, page, fp)) {
930 if (object) {
931 object_err(s, page, object,
932 "Freechain corrupt");
933 set_freepointer(s, object, NULL);
934 } else {
935 slab_err(s, page, "Freepointer corrupt");
936 page->freelist = NULL;
937 page->inuse = page->objects;
938 slab_fix(s, "Freelist cleared");
939 return 0;
940 }
941 break;
942 }
943 object = fp;
944 fp = get_freepointer(s, object);
945 nr++;
946 }
947
948 max_objects = order_objects(compound_order(page), s->size, s->reserved);
949 if (max_objects > MAX_OBJS_PER_PAGE)
950 max_objects = MAX_OBJS_PER_PAGE;
951
952 if (page->objects != max_objects) {
953 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
954 page->objects, max_objects);
955 page->objects = max_objects;
956 slab_fix(s, "Number of objects adjusted.");
957 }
958 if (page->inuse != page->objects - nr) {
959 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
960 page->inuse, page->objects - nr);
961 page->inuse = page->objects - nr;
962 slab_fix(s, "Object count adjusted.");
963 }
964 return search == NULL;
965}
966
967static void trace(struct kmem_cache *s, struct page *page, void *object,
968 int alloc)
969{
970 if (s->flags & SLAB_TRACE) {
971 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
972 s->name,
973 alloc ? "alloc" : "free",
974 object, page->inuse,
975 page->freelist);
976
977 if (!alloc)
978 print_section("Object ", (void *)object,
979 s->object_size);
980
981 dump_stack();
982 }
983}
984
985/*
986 * Tracking of fully allocated slabs for debugging purposes.
987 */
988static void add_full(struct kmem_cache *s,
989 struct kmem_cache_node *n, struct page *page)
990{
991 if (!(s->flags & SLAB_STORE_USER))
992 return;
993
994 lockdep_assert_held(&n->list_lock);
995 list_add(&page->lru, &n->full);
996}
997
998static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
999{
1000 if (!(s->flags & SLAB_STORE_USER))
1001 return;
1002
1003 lockdep_assert_held(&n->list_lock);
1004 list_del(&page->lru);
1005}
1006
1007/* Tracking of the number of slabs for debugging purposes */
1008static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1009{
1010 struct kmem_cache_node *n = get_node(s, node);
1011
1012 return atomic_long_read(&n->nr_slabs);
1013}
1014
1015static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1016{
1017 return atomic_long_read(&n->nr_slabs);
1018}
1019
1020static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1021{
1022 struct kmem_cache_node *n = get_node(s, node);
1023
1024 /*
1025 * May be called early in order to allocate a slab for the
1026 * kmem_cache_node structure. Solve the chicken-egg
1027 * dilemma by deferring the increment of the count during
1028 * bootstrap (see early_kmem_cache_node_alloc).
1029 */
1030 if (likely(n)) {
1031 atomic_long_inc(&n->nr_slabs);
1032 atomic_long_add(objects, &n->total_objects);
1033 }
1034}
1035static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1036{
1037 struct kmem_cache_node *n = get_node(s, node);
1038
1039 atomic_long_dec(&n->nr_slabs);
1040 atomic_long_sub(objects, &n->total_objects);
1041}
1042
1043/* Object debug checks for alloc/free paths */
1044static void setup_object_debug(struct kmem_cache *s, struct page *page,
1045 void *object)
1046{
1047 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1048 return;
1049
1050 init_object(s, object, SLUB_RED_INACTIVE);
1051 init_tracking(s, object);
1052}
1053
1054static inline int alloc_consistency_checks(struct kmem_cache *s,
1055 struct page *page,
1056 void *object, unsigned long addr)
1057{
1058 if (!check_slab(s, page))
1059 return 0;
1060
1061 if (!check_valid_pointer(s, page, object)) {
1062 object_err(s, page, object, "Freelist Pointer check fails");
1063 return 0;
1064 }
1065
1066 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1067 return 0;
1068
1069 return 1;
1070}
1071
1072static noinline int alloc_debug_processing(struct kmem_cache *s,
1073 struct page *page,
1074 void *object, unsigned long addr)
1075{
1076 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1077 if (!alloc_consistency_checks(s, page, object, addr))
1078 goto bad;
1079 }
1080
1081 /* Success perform special debug activities for allocs */
1082 if (s->flags & SLAB_STORE_USER)
1083 set_track(s, object, TRACK_ALLOC, addr);
1084 trace(s, page, object, 1);
1085 init_object(s, object, SLUB_RED_ACTIVE);
1086 return 1;
1087
1088bad:
1089 if (PageSlab(page)) {
1090 /*
1091 * If this is a slab page then lets do the best we can
1092 * to avoid issues in the future. Marking all objects
1093 * as used avoids touching the remaining objects.
1094 */
1095 slab_fix(s, "Marking all objects used");
1096 page->inuse = page->objects;
1097 page->freelist = NULL;
1098 }
1099 return 0;
1100}
1101
1102static inline int free_consistency_checks(struct kmem_cache *s,
1103 struct page *page, void *object, unsigned long addr)
1104{
1105 if (!check_valid_pointer(s, page, object)) {
1106 slab_err(s, page, "Invalid object pointer 0x%p", object);
1107 return 0;
1108 }
1109
1110 if (on_freelist(s, page, object)) {
1111 object_err(s, page, object, "Object already free");
1112 return 0;
1113 }
1114
1115 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1116 return 0;
1117
1118 if (unlikely(s != page->slab_cache)) {
1119 if (!PageSlab(page)) {
1120 slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1121 object);
1122 } else if (!page->slab_cache) {
1123 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1124 object);
1125 dump_stack();
1126 } else
1127 object_err(s, page, object,
1128 "page slab pointer corrupt.");
1129 return 0;
1130 }
1131 return 1;
1132}
1133
1134/* Supports checking bulk free of a constructed freelist */
1135static noinline int free_debug_processing(
1136 struct kmem_cache *s, struct page *page,
1137 void *head, void *tail, int bulk_cnt,
1138 unsigned long addr)
1139{
1140 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1141 void *object = head;
1142 int cnt = 0;
1143 unsigned long uninitialized_var(flags);
1144 int ret = 0;
1145
1146 spin_lock_irqsave(&n->list_lock, flags);
1147 slab_lock(page);
1148
1149 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1150 if (!check_slab(s, page))
1151 goto out;
1152 }
1153
1154next_object:
1155 cnt++;
1156
1157 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1158 if (!free_consistency_checks(s, page, object, addr))
1159 goto out;
1160 }
1161
1162 if (s->flags & SLAB_STORE_USER)
1163 set_track(s, object, TRACK_FREE, addr);
1164 trace(s, page, object, 0);
1165 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1166 init_object(s, object, SLUB_RED_INACTIVE);
1167
1168 /* Reached end of constructed freelist yet? */
1169 if (object != tail) {
1170 object = get_freepointer(s, object);
1171 goto next_object;
1172 }
1173 ret = 1;
1174
1175out:
1176 if (cnt != bulk_cnt)
1177 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1178 bulk_cnt, cnt);
1179
1180 slab_unlock(page);
1181 spin_unlock_irqrestore(&n->list_lock, flags);
1182 if (!ret)
1183 slab_fix(s, "Object at 0x%p not freed", object);
1184 return ret;
1185}
1186
1187static int __init setup_slub_debug(char *str)
1188{
1189 slub_debug = DEBUG_DEFAULT_FLAGS;
1190 if (*str++ != '=' || !*str)
1191 /*
1192 * No options specified. Switch on full debugging.
1193 */
1194 goto out;
1195
1196 if (*str == ',')
1197 /*
1198 * No options but restriction on slabs. This means full
1199 * debugging for slabs matching a pattern.
1200 */
1201 goto check_slabs;
1202
1203 slub_debug = 0;
1204 if (*str == '-')
1205 /*
1206 * Switch off all debugging measures.
1207 */
1208 goto out;
1209
1210 /*
1211 * Determine which debug features should be switched on
1212 */
1213 for (; *str && *str != ','; str++) {
1214 switch (tolower(*str)) {
1215 case 'f':
1216 slub_debug |= SLAB_CONSISTENCY_CHECKS;
1217 break;
1218 case 'z':
1219 slub_debug |= SLAB_RED_ZONE;
1220 break;
1221 case 'p':
1222 slub_debug |= SLAB_POISON;
1223 break;
1224 case 'u':
1225 slub_debug |= SLAB_STORE_USER;
1226 break;
1227 case 't':
1228 slub_debug |= SLAB_TRACE;
1229 break;
1230 case 'a':
1231 slub_debug |= SLAB_FAILSLAB;
1232 break;
1233 case 'o':
1234 /*
1235 * Avoid enabling debugging on caches if its minimum
1236 * order would increase as a result.
1237 */
1238 disable_higher_order_debug = 1;
1239 break;
1240 default:
1241 pr_err("slub_debug option '%c' unknown. skipped\n",
1242 *str);
1243 }
1244 }
1245
1246check_slabs:
1247 if (*str == ',')
1248 slub_debug_slabs = str + 1;
1249out:
1250 return 1;
1251}
1252
1253__setup("slub_debug", setup_slub_debug);
1254
1255unsigned long kmem_cache_flags(unsigned long object_size,
1256 unsigned long flags, const char *name,
1257 void (*ctor)(void *))
1258{
1259 /*
1260 * Enable debugging if selected on the kernel commandline.
1261 */
1262 if (slub_debug && (!slub_debug_slabs || (name &&
1263 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))))
1264 flags |= slub_debug;
1265
1266 return flags;
1267}
1268#else /* !CONFIG_SLUB_DEBUG */
1269static inline void setup_object_debug(struct kmem_cache *s,
1270 struct page *page, void *object) {}
1271
1272static inline int alloc_debug_processing(struct kmem_cache *s,
1273 struct page *page, void *object, unsigned long addr) { return 0; }
1274
1275static inline int free_debug_processing(
1276 struct kmem_cache *s, struct page *page,
1277 void *head, void *tail, int bulk_cnt,
1278 unsigned long addr) { return 0; }
1279
1280static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1281 { return 1; }
1282static inline int check_object(struct kmem_cache *s, struct page *page,
1283 void *object, u8 val) { return 1; }
1284static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1285 struct page *page) {}
1286static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1287 struct page *page) {}
1288unsigned long kmem_cache_flags(unsigned long object_size,
1289 unsigned long flags, const char *name,
1290 void (*ctor)(void *))
1291{
1292 return flags;
1293}
1294#define slub_debug 0
1295
1296#define disable_higher_order_debug 0
1297
1298static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1299 { return 0; }
1300static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1301 { return 0; }
1302static inline void inc_slabs_node(struct kmem_cache *s, int node,
1303 int objects) {}
1304static inline void dec_slabs_node(struct kmem_cache *s, int node,
1305 int objects) {}
1306
1307#endif /* CONFIG_SLUB_DEBUG */
1308
1309/*
1310 * Hooks for other subsystems that check memory allocations. In a typical
1311 * production configuration these hooks all should produce no code at all.
1312 */
1313static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1314{
1315 kmemleak_alloc(ptr, size, 1, flags);
1316 kasan_kmalloc_large(ptr, size, flags);
1317}
1318
1319static inline void kfree_hook(const void *x)
1320{
1321 kmemleak_free(x);
1322 kasan_kfree_large(x);
1323}
1324
1325static inline void slab_free_hook(struct kmem_cache *s, void *x)
1326{
1327 kmemleak_free_recursive(x, s->flags);
1328
1329 /*
1330 * Trouble is that we may no longer disable interrupts in the fast path
1331 * So in order to make the debug calls that expect irqs to be
1332 * disabled we need to disable interrupts temporarily.
1333 */
1334#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1335 {
1336 unsigned long flags;
1337
1338 local_irq_save(flags);
1339 kmemcheck_slab_free(s, x, s->object_size);
1340 debug_check_no_locks_freed(x, s->object_size);
1341 local_irq_restore(flags);
1342 }
1343#endif
1344 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1345 debug_check_no_obj_freed(x, s->object_size);
1346
1347 kasan_slab_free(s, x);
1348}
1349
1350static inline void slab_free_freelist_hook(struct kmem_cache *s,
1351 void *head, void *tail)
1352{
1353/*
1354 * Compiler cannot detect this function can be removed if slab_free_hook()
1355 * evaluates to nothing. Thus, catch all relevant config debug options here.
1356 */
1357#if defined(CONFIG_KMEMCHECK) || \
1358 defined(CONFIG_LOCKDEP) || \
1359 defined(CONFIG_DEBUG_KMEMLEAK) || \
1360 defined(CONFIG_DEBUG_OBJECTS_FREE) || \
1361 defined(CONFIG_KASAN)
1362
1363 void *object = head;
1364 void *tail_obj = tail ? : head;
1365
1366 do {
1367 slab_free_hook(s, object);
1368 } while ((object != tail_obj) &&
1369 (object = get_freepointer(s, object)));
1370#endif
1371}
1372
1373static void setup_object(struct kmem_cache *s, struct page *page,
1374 void *object)
1375{
1376 setup_object_debug(s, page, object);
1377 if (unlikely(s->ctor)) {
1378 kasan_unpoison_object_data(s, object);
1379 s->ctor(object);
1380 kasan_poison_object_data(s, object);
1381 }
1382}
1383
1384/*
1385 * Slab allocation and freeing
1386 */
1387static inline struct page *alloc_slab_page(struct kmem_cache *s,
1388 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1389{
1390 struct page *page;
1391 int order = oo_order(oo);
1392
1393 flags |= __GFP_NOTRACK;
1394
1395 if (node == NUMA_NO_NODE)
1396 page = alloc_pages(flags, order);
1397 else
1398 page = __alloc_pages_node(node, flags, order);
1399
1400 if (page && memcg_charge_slab(page, flags, order, s)) {
1401 __free_pages(page, order);
1402 page = NULL;
1403 }
1404
1405 return page;
1406}
1407
1408static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1409{
1410 struct page *page;
1411 struct kmem_cache_order_objects oo = s->oo;
1412 gfp_t alloc_gfp;
1413 void *start, *p;
1414 int idx, order;
1415
1416 flags &= gfp_allowed_mask;
1417
1418 if (gfpflags_allow_blocking(flags))
1419 local_irq_enable();
1420
1421 flags |= s->allocflags;
1422
1423 /*
1424 * Let the initial higher-order allocation fail under memory pressure
1425 * so we fall-back to the minimum order allocation.
1426 */
1427 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1428 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1429 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1430
1431 page = alloc_slab_page(s, alloc_gfp, node, oo);
1432 if (unlikely(!page)) {
1433 oo = s->min;
1434 alloc_gfp = flags;
1435 /*
1436 * Allocation may have failed due to fragmentation.
1437 * Try a lower order alloc if possible
1438 */
1439 page = alloc_slab_page(s, alloc_gfp, node, oo);
1440 if (unlikely(!page))
1441 goto out;
1442 stat(s, ORDER_FALLBACK);
1443 }
1444
1445 if (kmemcheck_enabled &&
1446 !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1447 int pages = 1 << oo_order(oo);
1448
1449 kmemcheck_alloc_shadow(page, oo_order(oo), alloc_gfp, node);
1450
1451 /*
1452 * Objects from caches that have a constructor don't get
1453 * cleared when they're allocated, so we need to do it here.
1454 */
1455 if (s->ctor)
1456 kmemcheck_mark_uninitialized_pages(page, pages);
1457 else
1458 kmemcheck_mark_unallocated_pages(page, pages);
1459 }
1460
1461 page->objects = oo_objects(oo);
1462
1463 order = compound_order(page);
1464 page->slab_cache = s;
1465 __SetPageSlab(page);
1466 if (page_is_pfmemalloc(page))
1467 SetPageSlabPfmemalloc(page);
1468
1469 start = page_address(page);
1470
1471 if (unlikely(s->flags & SLAB_POISON))
1472 memset(start, POISON_INUSE, PAGE_SIZE << order);
1473
1474 kasan_poison_slab(page);
1475
1476 for_each_object_idx(p, idx, s, start, page->objects) {
1477 setup_object(s, page, p);
1478 if (likely(idx < page->objects))
1479 set_freepointer(s, p, p + s->size);
1480 else
1481 set_freepointer(s, p, NULL);
1482 }
1483
1484 page->freelist = fixup_red_left(s, start);
1485 page->inuse = page->objects;
1486 page->frozen = 1;
1487
1488out:
1489 if (gfpflags_allow_blocking(flags))
1490 local_irq_disable();
1491 if (!page)
1492 return NULL;
1493
1494 mod_zone_page_state(page_zone(page),
1495 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1496 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1497 1 << oo_order(oo));
1498
1499 inc_slabs_node(s, page_to_nid(page), page->objects);
1500
1501 return page;
1502}
1503
1504static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1505{
1506 if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1507 pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
1508 BUG();
1509 }
1510
1511 return allocate_slab(s,
1512 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1513}
1514
1515static void __free_slab(struct kmem_cache *s, struct page *page)
1516{
1517 int order = compound_order(page);
1518 int pages = 1 << order;
1519
1520 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1521 void *p;
1522
1523 slab_pad_check(s, page);
1524 for_each_object(p, s, page_address(page),
1525 page->objects)
1526 check_object(s, page, p, SLUB_RED_INACTIVE);
1527 }
1528
1529 kmemcheck_free_shadow(page, compound_order(page));
1530
1531 mod_zone_page_state(page_zone(page),
1532 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1533 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1534 -pages);
1535
1536 __ClearPageSlabPfmemalloc(page);
1537 __ClearPageSlab(page);
1538
1539 page_mapcount_reset(page);
1540 if (current->reclaim_state)
1541 current->reclaim_state->reclaimed_slab += pages;
1542 memcg_uncharge_slab(page, order, s);
1543 __free_pages(page, order);
1544}
1545
1546#define need_reserve_slab_rcu \
1547 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1548
1549static void rcu_free_slab(struct rcu_head *h)
1550{
1551 struct page *page;
1552
1553 if (need_reserve_slab_rcu)
1554 page = virt_to_head_page(h);
1555 else
1556 page = container_of((struct list_head *)h, struct page, lru);
1557
1558 __free_slab(page->slab_cache, page);
1559}
1560
1561static void free_slab(struct kmem_cache *s, struct page *page)
1562{
1563 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1564 struct rcu_head *head;
1565
1566 if (need_reserve_slab_rcu) {
1567 int order = compound_order(page);
1568 int offset = (PAGE_SIZE << order) - s->reserved;
1569
1570 VM_BUG_ON(s->reserved != sizeof(*head));
1571 head = page_address(page) + offset;
1572 } else {
1573 head = &page->rcu_head;
1574 }
1575
1576 call_rcu(head, rcu_free_slab);
1577 } else
1578 __free_slab(s, page);
1579}
1580
1581static void discard_slab(struct kmem_cache *s, struct page *page)
1582{
1583 dec_slabs_node(s, page_to_nid(page), page->objects);
1584 free_slab(s, page);
1585}
1586
1587/*
1588 * Management of partially allocated slabs.
1589 */
1590static inline void
1591__add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1592{
1593 n->nr_partial++;
1594 if (tail == DEACTIVATE_TO_TAIL)
1595 list_add_tail(&page->lru, &n->partial);
1596 else
1597 list_add(&page->lru, &n->partial);
1598}
1599
1600static inline void add_partial(struct kmem_cache_node *n,
1601 struct page *page, int tail)
1602{
1603 lockdep_assert_held(&n->list_lock);
1604 __add_partial(n, page, tail);
1605}
1606
1607static inline void remove_partial(struct kmem_cache_node *n,
1608 struct page *page)
1609{
1610 lockdep_assert_held(&n->list_lock);
1611 list_del(&page->lru);
1612 n->nr_partial--;
1613}
1614
1615/*
1616 * Remove slab from the partial list, freeze it and
1617 * return the pointer to the freelist.
1618 *
1619 * Returns a list of objects or NULL if it fails.
1620 */
1621static inline void *acquire_slab(struct kmem_cache *s,
1622 struct kmem_cache_node *n, struct page *page,
1623 int mode, int *objects)
1624{
1625 void *freelist;
1626 unsigned long counters;
1627 struct page new;
1628
1629 lockdep_assert_held(&n->list_lock);
1630
1631 /*
1632 * Zap the freelist and set the frozen bit.
1633 * The old freelist is the list of objects for the
1634 * per cpu allocation list.
1635 */
1636 freelist = page->freelist;
1637 counters = page->counters;
1638 new.counters = counters;
1639 *objects = new.objects - new.inuse;
1640 if (mode) {
1641 new.inuse = page->objects;
1642 new.freelist = NULL;
1643 } else {
1644 new.freelist = freelist;
1645 }
1646
1647 VM_BUG_ON(new.frozen);
1648 new.frozen = 1;
1649
1650 if (!__cmpxchg_double_slab(s, page,
1651 freelist, counters,
1652 new.freelist, new.counters,
1653 "acquire_slab"))
1654 return NULL;
1655
1656 remove_partial(n, page);
1657 WARN_ON(!freelist);
1658 return freelist;
1659}
1660
1661static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1662static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1663
1664/*
1665 * Try to allocate a partial slab from a specific node.
1666 */
1667static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1668 struct kmem_cache_cpu *c, gfp_t flags)
1669{
1670 struct page *page, *page2;
1671 void *object = NULL;
1672 int available = 0;
1673 int objects;
1674
1675 /*
1676 * Racy check. If we mistakenly see no partial slabs then we
1677 * just allocate an empty slab. If we mistakenly try to get a
1678 * partial slab and there is none available then get_partials()
1679 * will return NULL.
1680 */
1681 if (!n || !n->nr_partial)
1682 return NULL;
1683
1684 spin_lock(&n->list_lock);
1685 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1686 void *t;
1687
1688 if (!pfmemalloc_match(page, flags))
1689 continue;
1690
1691 t = acquire_slab(s, n, page, object == NULL, &objects);
1692 if (!t)
1693 break;
1694
1695 available += objects;
1696 if (!object) {
1697 c->page = page;
1698 stat(s, ALLOC_FROM_PARTIAL);
1699 object = t;
1700 } else {
1701 put_cpu_partial(s, page, 0);
1702 stat(s, CPU_PARTIAL_NODE);
1703 }
1704 if (!kmem_cache_has_cpu_partial(s)
1705 || available > s->cpu_partial / 2)
1706 break;
1707
1708 }
1709 spin_unlock(&n->list_lock);
1710 return object;
1711}
1712
1713/*
1714 * Get a page from somewhere. Search in increasing NUMA distances.
1715 */
1716static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1717 struct kmem_cache_cpu *c)
1718{
1719#ifdef CONFIG_NUMA
1720 struct zonelist *zonelist;
1721 struct zoneref *z;
1722 struct zone *zone;
1723 enum zone_type high_zoneidx = gfp_zone(flags);
1724 void *object;
1725 unsigned int cpuset_mems_cookie;
1726
1727 /*
1728 * The defrag ratio allows a configuration of the tradeoffs between
1729 * inter node defragmentation and node local allocations. A lower
1730 * defrag_ratio increases the tendency to do local allocations
1731 * instead of attempting to obtain partial slabs from other nodes.
1732 *
1733 * If the defrag_ratio is set to 0 then kmalloc() always
1734 * returns node local objects. If the ratio is higher then kmalloc()
1735 * may return off node objects because partial slabs are obtained
1736 * from other nodes and filled up.
1737 *
1738 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1739 * defrag_ratio = 1000) then every (well almost) allocation will
1740 * first attempt to defrag slab caches on other nodes. This means
1741 * scanning over all nodes to look for partial slabs which may be
1742 * expensive if we do it every time we are trying to find a slab
1743 * with available objects.
1744 */
1745 if (!s->remote_node_defrag_ratio ||
1746 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1747 return NULL;
1748
1749 do {
1750 cpuset_mems_cookie = read_mems_allowed_begin();
1751 zonelist = node_zonelist(mempolicy_slab_node(), flags);
1752 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1753 struct kmem_cache_node *n;
1754
1755 n = get_node(s, zone_to_nid(zone));
1756
1757 if (n && cpuset_zone_allowed(zone, flags) &&
1758 n->nr_partial > s->min_partial) {
1759 object = get_partial_node(s, n, c, flags);
1760 if (object) {
1761 /*
1762 * Don't check read_mems_allowed_retry()
1763 * here - if mems_allowed was updated in
1764 * parallel, that was a harmless race
1765 * between allocation and the cpuset
1766 * update
1767 */
1768 return object;
1769 }
1770 }
1771 }
1772 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1773#endif
1774 return NULL;
1775}
1776
1777/*
1778 * Get a partial page, lock it and return it.
1779 */
1780static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1781 struct kmem_cache_cpu *c)
1782{
1783 void *object;
1784 int searchnode = node;
1785
1786 if (node == NUMA_NO_NODE)
1787 searchnode = numa_mem_id();
1788 else if (!node_present_pages(node))
1789 searchnode = node_to_mem_node(node);
1790
1791 object = get_partial_node(s, get_node(s, searchnode), c, flags);
1792 if (object || node != NUMA_NO_NODE)
1793 return object;
1794
1795 return get_any_partial(s, flags, c);
1796}
1797
1798#ifdef CONFIG_PREEMPT
1799/*
1800 * Calculate the next globally unique transaction for disambiguiation
1801 * during cmpxchg. The transactions start with the cpu number and are then
1802 * incremented by CONFIG_NR_CPUS.
1803 */
1804#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1805#else
1806/*
1807 * No preemption supported therefore also no need to check for
1808 * different cpus.
1809 */
1810#define TID_STEP 1
1811#endif
1812
1813static inline unsigned long next_tid(unsigned long tid)
1814{
1815 return tid + TID_STEP;
1816}
1817
1818static inline unsigned int tid_to_cpu(unsigned long tid)
1819{
1820 return tid % TID_STEP;
1821}
1822
1823static inline unsigned long tid_to_event(unsigned long tid)
1824{
1825 return tid / TID_STEP;
1826}
1827
1828static inline unsigned int init_tid(int cpu)
1829{
1830 return cpu;
1831}
1832
1833static inline void note_cmpxchg_failure(const char *n,
1834 const struct kmem_cache *s, unsigned long tid)
1835{
1836#ifdef SLUB_DEBUG_CMPXCHG
1837 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1838
1839 pr_info("%s %s: cmpxchg redo ", n, s->name);
1840
1841#ifdef CONFIG_PREEMPT
1842 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1843 pr_warn("due to cpu change %d -> %d\n",
1844 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1845 else
1846#endif
1847 if (tid_to_event(tid) != tid_to_event(actual_tid))
1848 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1849 tid_to_event(tid), tid_to_event(actual_tid));
1850 else
1851 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1852 actual_tid, tid, next_tid(tid));
1853#endif
1854 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1855}
1856
1857static void init_kmem_cache_cpus(struct kmem_cache *s)
1858{
1859 int cpu;
1860
1861 for_each_possible_cpu(cpu)
1862 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1863}
1864
1865/*
1866 * Remove the cpu slab
1867 */
1868static void deactivate_slab(struct kmem_cache *s, struct page *page,
1869 void *freelist)
1870{
1871 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1872 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1873 int lock = 0;
1874 enum slab_modes l = M_NONE, m = M_NONE;
1875 void *nextfree;
1876 int tail = DEACTIVATE_TO_HEAD;
1877 struct page new;
1878 struct page old;
1879
1880 if (page->freelist) {
1881 stat(s, DEACTIVATE_REMOTE_FREES);
1882 tail = DEACTIVATE_TO_TAIL;
1883 }
1884
1885 /*
1886 * Stage one: Free all available per cpu objects back
1887 * to the page freelist while it is still frozen. Leave the
1888 * last one.
1889 *
1890 * There is no need to take the list->lock because the page
1891 * is still frozen.
1892 */
1893 while (freelist && (nextfree = get_freepointer(s, freelist))) {
1894 void *prior;
1895 unsigned long counters;
1896
1897 do {
1898 prior = page->freelist;
1899 counters = page->counters;
1900 set_freepointer(s, freelist, prior);
1901 new.counters = counters;
1902 new.inuse--;
1903 VM_BUG_ON(!new.frozen);
1904
1905 } while (!__cmpxchg_double_slab(s, page,
1906 prior, counters,
1907 freelist, new.counters,
1908 "drain percpu freelist"));
1909
1910 freelist = nextfree;
1911 }
1912
1913 /*
1914 * Stage two: Ensure that the page is unfrozen while the
1915 * list presence reflects the actual number of objects
1916 * during unfreeze.
1917 *
1918 * We setup the list membership and then perform a cmpxchg
1919 * with the count. If there is a mismatch then the page
1920 * is not unfrozen but the page is on the wrong list.
1921 *
1922 * Then we restart the process which may have to remove
1923 * the page from the list that we just put it on again
1924 * because the number of objects in the slab may have
1925 * changed.
1926 */
1927redo:
1928
1929 old.freelist = page->freelist;
1930 old.counters = page->counters;
1931 VM_BUG_ON(!old.frozen);
1932
1933 /* Determine target state of the slab */
1934 new.counters = old.counters;
1935 if (freelist) {
1936 new.inuse--;
1937 set_freepointer(s, freelist, old.freelist);
1938 new.freelist = freelist;
1939 } else
1940 new.freelist = old.freelist;
1941
1942 new.frozen = 0;
1943
1944 if (!new.inuse && n->nr_partial >= s->min_partial)
1945 m = M_FREE;
1946 else if (new.freelist) {
1947 m = M_PARTIAL;
1948 if (!lock) {
1949 lock = 1;
1950 /*
1951 * Taking the spinlock removes the possiblity
1952 * that acquire_slab() will see a slab page that
1953 * is frozen
1954 */
1955 spin_lock(&n->list_lock);
1956 }
1957 } else {
1958 m = M_FULL;
1959 if (kmem_cache_debug(s) && !lock) {
1960 lock = 1;
1961 /*
1962 * This also ensures that the scanning of full
1963 * slabs from diagnostic functions will not see
1964 * any frozen slabs.
1965 */
1966 spin_lock(&n->list_lock);
1967 }
1968 }
1969
1970 if (l != m) {
1971
1972 if (l == M_PARTIAL)
1973
1974 remove_partial(n, page);
1975
1976 else if (l == M_FULL)
1977
1978 remove_full(s, n, page);
1979
1980 if (m == M_PARTIAL) {
1981
1982 add_partial(n, page, tail);
1983 stat(s, tail);
1984
1985 } else if (m == M_FULL) {
1986
1987 stat(s, DEACTIVATE_FULL);
1988 add_full(s, n, page);
1989
1990 }
1991 }
1992
1993 l = m;
1994 if (!__cmpxchg_double_slab(s, page,
1995 old.freelist, old.counters,
1996 new.freelist, new.counters,
1997 "unfreezing slab"))
1998 goto redo;
1999
2000 if (lock)
2001 spin_unlock(&n->list_lock);
2002
2003 if (m == M_FREE) {
2004 stat(s, DEACTIVATE_EMPTY);
2005 discard_slab(s, page);
2006 stat(s, FREE_SLAB);
2007 }
2008}
2009
2010/*
2011 * Unfreeze all the cpu partial slabs.
2012 *
2013 * This function must be called with interrupts disabled
2014 * for the cpu using c (or some other guarantee must be there
2015 * to guarantee no concurrent accesses).
2016 */
2017static void unfreeze_partials(struct kmem_cache *s,
2018 struct kmem_cache_cpu *c)
2019{
2020#ifdef CONFIG_SLUB_CPU_PARTIAL
2021 struct kmem_cache_node *n = NULL, *n2 = NULL;
2022 struct page *page, *discard_page = NULL;
2023
2024 while ((page = c->partial)) {
2025 struct page new;
2026 struct page old;
2027
2028 c->partial = page->next;
2029
2030 n2 = get_node(s, page_to_nid(page));
2031 if (n != n2) {
2032 if (n)
2033 spin_unlock(&n->list_lock);
2034
2035 n = n2;
2036 spin_lock(&n->list_lock);
2037 }
2038
2039 do {
2040
2041 old.freelist = page->freelist;
2042 old.counters = page->counters;
2043 VM_BUG_ON(!old.frozen);
2044
2045 new.counters = old.counters;
2046 new.freelist = old.freelist;
2047
2048 new.frozen = 0;
2049
2050 } while (!__cmpxchg_double_slab(s, page,
2051 old.freelist, old.counters,
2052 new.freelist, new.counters,
2053 "unfreezing slab"));
2054
2055 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2056 page->next = discard_page;
2057 discard_page = page;
2058 } else {
2059 add_partial(n, page, DEACTIVATE_TO_TAIL);
2060 stat(s, FREE_ADD_PARTIAL);
2061 }
2062 }
2063
2064 if (n)
2065 spin_unlock(&n->list_lock);
2066
2067 while (discard_page) {
2068 page = discard_page;
2069 discard_page = discard_page->next;
2070
2071 stat(s, DEACTIVATE_EMPTY);
2072 discard_slab(s, page);
2073 stat(s, FREE_SLAB);
2074 }
2075#endif
2076}
2077
2078/*
2079 * Put a page that was just frozen (in __slab_free) into a partial page
2080 * slot if available. This is done without interrupts disabled and without
2081 * preemption disabled. The cmpxchg is racy and may put the partial page
2082 * onto a random cpus partial slot.
2083 *
2084 * If we did not find a slot then simply move all the partials to the
2085 * per node partial list.
2086 */
2087static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2088{
2089#ifdef CONFIG_SLUB_CPU_PARTIAL
2090 struct page *oldpage;
2091 int pages;
2092 int pobjects;
2093
2094 preempt_disable();
2095 do {
2096 pages = 0;
2097 pobjects = 0;
2098 oldpage = this_cpu_read(s->cpu_slab->partial);
2099
2100 if (oldpage) {
2101 pobjects = oldpage->pobjects;
2102 pages = oldpage->pages;
2103 if (drain && pobjects > s->cpu_partial) {
2104 unsigned long flags;
2105 /*
2106 * partial array is full. Move the existing
2107 * set to the per node partial list.
2108 */
2109 local_irq_save(flags);
2110 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2111 local_irq_restore(flags);
2112 oldpage = NULL;
2113 pobjects = 0;
2114 pages = 0;
2115 stat(s, CPU_PARTIAL_DRAIN);
2116 }
2117 }
2118
2119 pages++;
2120 pobjects += page->objects - page->inuse;
2121
2122 page->pages = pages;
2123 page->pobjects = pobjects;
2124 page->next = oldpage;
2125
2126 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2127 != oldpage);
2128 if (unlikely(!s->cpu_partial)) {
2129 unsigned long flags;
2130
2131 local_irq_save(flags);
2132 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2133 local_irq_restore(flags);
2134 }
2135 preempt_enable();
2136#endif
2137}
2138
2139static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2140{
2141 stat(s, CPUSLAB_FLUSH);
2142 deactivate_slab(s, c->page, c->freelist);
2143
2144 c->tid = next_tid(c->tid);
2145 c->page = NULL;
2146 c->freelist = NULL;
2147}
2148
2149/*
2150 * Flush cpu slab.
2151 *
2152 * Called from IPI handler with interrupts disabled.
2153 */
2154static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2155{
2156 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2157
2158 if (likely(c)) {
2159 if (c->page)
2160 flush_slab(s, c);
2161
2162 unfreeze_partials(s, c);
2163 }
2164}
2165
2166static void flush_cpu_slab(void *d)
2167{
2168 struct kmem_cache *s = d;
2169
2170 __flush_cpu_slab(s, smp_processor_id());
2171}
2172
2173static bool has_cpu_slab(int cpu, void *info)
2174{
2175 struct kmem_cache *s = info;
2176 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2177
2178 return c->page || c->partial;
2179}
2180
2181static void flush_all(struct kmem_cache *s)
2182{
2183 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2184}
2185
2186/*
2187 * Check if the objects in a per cpu structure fit numa
2188 * locality expectations.
2189 */
2190static inline int node_match(struct page *page, int node)
2191{
2192#ifdef CONFIG_NUMA
2193 if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2194 return 0;
2195#endif
2196 return 1;
2197}
2198
2199#ifdef CONFIG_SLUB_DEBUG
2200static int count_free(struct page *page)
2201{
2202 return page->objects - page->inuse;
2203}
2204
2205static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2206{
2207 return atomic_long_read(&n->total_objects);
2208}
2209#endif /* CONFIG_SLUB_DEBUG */
2210
2211#if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2212static unsigned long count_partial(struct kmem_cache_node *n,
2213 int (*get_count)(struct page *))
2214{
2215 unsigned long flags;
2216 unsigned long x = 0;
2217 struct page *page;
2218
2219 spin_lock_irqsave(&n->list_lock, flags);
2220 list_for_each_entry(page, &n->partial, lru)
2221 x += get_count(page);
2222 spin_unlock_irqrestore(&n->list_lock, flags);
2223 return x;
2224}
2225#endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2226
2227static noinline void
2228slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2229{
2230#ifdef CONFIG_SLUB_DEBUG
2231 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2232 DEFAULT_RATELIMIT_BURST);
2233 int node;
2234 struct kmem_cache_node *n;
2235
2236 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2237 return;
2238
2239 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2240 nid, gfpflags, &gfpflags);
2241 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2242 s->name, s->object_size, s->size, oo_order(s->oo),
2243 oo_order(s->min));
2244
2245 if (oo_order(s->min) > get_order(s->object_size))
2246 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2247 s->name);
2248
2249 for_each_kmem_cache_node(s, node, n) {
2250 unsigned long nr_slabs;
2251 unsigned long nr_objs;
2252 unsigned long nr_free;
2253
2254 nr_free = count_partial(n, count_free);
2255 nr_slabs = node_nr_slabs(n);
2256 nr_objs = node_nr_objs(n);
2257
2258 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2259 node, nr_slabs, nr_objs, nr_free);
2260 }
2261#endif
2262}
2263
2264static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2265 int node, struct kmem_cache_cpu **pc)
2266{
2267 void *freelist;
2268 struct kmem_cache_cpu *c = *pc;
2269 struct page *page;
2270
2271 freelist = get_partial(s, flags, node, c);
2272
2273 if (freelist)
2274 return freelist;
2275
2276 page = new_slab(s, flags, node);
2277 if (page) {
2278 c = raw_cpu_ptr(s->cpu_slab);
2279 if (c->page)
2280 flush_slab(s, c);
2281
2282 /*
2283 * No other reference to the page yet so we can
2284 * muck around with it freely without cmpxchg
2285 */
2286 freelist = page->freelist;
2287 page->freelist = NULL;
2288
2289 stat(s, ALLOC_SLAB);
2290 c->page = page;
2291 *pc = c;
2292 } else
2293 freelist = NULL;
2294
2295 return freelist;
2296}
2297
2298static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2299{
2300 if (unlikely(PageSlabPfmemalloc(page)))
2301 return gfp_pfmemalloc_allowed(gfpflags);
2302
2303 return true;
2304}
2305
2306/*
2307 * Check the page->freelist of a page and either transfer the freelist to the
2308 * per cpu freelist or deactivate the page.
2309 *
2310 * The page is still frozen if the return value is not NULL.
2311 *
2312 * If this function returns NULL then the page has been unfrozen.
2313 *
2314 * This function must be called with interrupt disabled.
2315 */
2316static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2317{
2318 struct page new;
2319 unsigned long counters;
2320 void *freelist;
2321
2322 do {
2323 freelist = page->freelist;
2324 counters = page->counters;
2325
2326 new.counters = counters;
2327 VM_BUG_ON(!new.frozen);
2328
2329 new.inuse = page->objects;
2330 new.frozen = freelist != NULL;
2331
2332 } while (!__cmpxchg_double_slab(s, page,
2333 freelist, counters,
2334 NULL, new.counters,
2335 "get_freelist"));
2336
2337 return freelist;
2338}
2339
2340/*
2341 * Slow path. The lockless freelist is empty or we need to perform
2342 * debugging duties.
2343 *
2344 * Processing is still very fast if new objects have been freed to the
2345 * regular freelist. In that case we simply take over the regular freelist
2346 * as the lockless freelist and zap the regular freelist.
2347 *
2348 * If that is not working then we fall back to the partial lists. We take the
2349 * first element of the freelist as the object to allocate now and move the
2350 * rest of the freelist to the lockless freelist.
2351 *
2352 * And if we were unable to get a new slab from the partial slab lists then
2353 * we need to allocate a new slab. This is the slowest path since it involves
2354 * a call to the page allocator and the setup of a new slab.
2355 *
2356 * Version of __slab_alloc to use when we know that interrupts are
2357 * already disabled (which is the case for bulk allocation).
2358 */
2359static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2360 unsigned long addr, struct kmem_cache_cpu *c)
2361{
2362 void *freelist;
2363 struct page *page;
2364
2365 page = c->page;
2366 if (!page)
2367 goto new_slab;
2368redo:
2369
2370 if (unlikely(!node_match(page, node))) {
2371 int searchnode = node;
2372
2373 if (node != NUMA_NO_NODE && !node_present_pages(node))
2374 searchnode = node_to_mem_node(node);
2375
2376 if (unlikely(!node_match(page, searchnode))) {
2377 stat(s, ALLOC_NODE_MISMATCH);
2378 deactivate_slab(s, page, c->freelist);
2379 c->page = NULL;
2380 c->freelist = NULL;
2381 goto new_slab;
2382 }
2383 }
2384
2385 /*
2386 * By rights, we should be searching for a slab page that was
2387 * PFMEMALLOC but right now, we are losing the pfmemalloc
2388 * information when the page leaves the per-cpu allocator
2389 */
2390 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2391 deactivate_slab(s, page, c->freelist);
2392 c->page = NULL;
2393 c->freelist = NULL;
2394 goto new_slab;
2395 }
2396
2397 /* must check again c->freelist in case of cpu migration or IRQ */
2398 freelist = c->freelist;
2399 if (freelist)
2400 goto load_freelist;
2401
2402 freelist = get_freelist(s, page);
2403
2404 if (!freelist) {
2405 c->page = NULL;
2406 stat(s, DEACTIVATE_BYPASS);
2407 goto new_slab;
2408 }
2409
2410 stat(s, ALLOC_REFILL);
2411
2412load_freelist:
2413 /*
2414 * freelist is pointing to the list of objects to be used.
2415 * page is pointing to the page from which the objects are obtained.
2416 * That page must be frozen for per cpu allocations to work.
2417 */
2418 VM_BUG_ON(!c->page->frozen);
2419 c->freelist = get_freepointer(s, freelist);
2420 c->tid = next_tid(c->tid);
2421 return freelist;
2422
2423new_slab:
2424
2425 if (c->partial) {
2426 page = c->page = c->partial;
2427 c->partial = page->next;
2428 stat(s, CPU_PARTIAL_ALLOC);
2429 c->freelist = NULL;
2430 goto redo;
2431 }
2432
2433 freelist = new_slab_objects(s, gfpflags, node, &c);
2434
2435 if (unlikely(!freelist)) {
2436 slab_out_of_memory(s, gfpflags, node);
2437 return NULL;
2438 }
2439
2440 page = c->page;
2441 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2442 goto load_freelist;
2443
2444 /* Only entered in the debug case */
2445 if (kmem_cache_debug(s) &&
2446 !alloc_debug_processing(s, page, freelist, addr))
2447 goto new_slab; /* Slab failed checks. Next slab needed */
2448
2449 deactivate_slab(s, page, get_freepointer(s, freelist));
2450 c->page = NULL;
2451 c->freelist = NULL;
2452 return freelist;
2453}
2454
2455/*
2456 * Another one that disabled interrupt and compensates for possible
2457 * cpu changes by refetching the per cpu area pointer.
2458 */
2459static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2460 unsigned long addr, struct kmem_cache_cpu *c)
2461{
2462 void *p;
2463 unsigned long flags;
2464
2465 local_irq_save(flags);
2466#ifdef CONFIG_PREEMPT
2467 /*
2468 * We may have been preempted and rescheduled on a different
2469 * cpu before disabling interrupts. Need to reload cpu area
2470 * pointer.
2471 */
2472 c = this_cpu_ptr(s->cpu_slab);
2473#endif
2474
2475 p = ___slab_alloc(s, gfpflags, node, addr, c);
2476 local_irq_restore(flags);
2477 return p;
2478}
2479
2480/*
2481 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2482 * have the fastpath folded into their functions. So no function call
2483 * overhead for requests that can be satisfied on the fastpath.
2484 *
2485 * The fastpath works by first checking if the lockless freelist can be used.
2486 * If not then __slab_alloc is called for slow processing.
2487 *
2488 * Otherwise we can simply pick the next object from the lockless free list.
2489 */
2490static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2491 gfp_t gfpflags, int node, unsigned long addr)
2492{
2493 void *object;
2494 struct kmem_cache_cpu *c;
2495 struct page *page;
2496 unsigned long tid;
2497
2498 s = slab_pre_alloc_hook(s, gfpflags);
2499 if (!s)
2500 return NULL;
2501redo:
2502 /*
2503 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2504 * enabled. We may switch back and forth between cpus while
2505 * reading from one cpu area. That does not matter as long
2506 * as we end up on the original cpu again when doing the cmpxchg.
2507 *
2508 * We should guarantee that tid and kmem_cache are retrieved on
2509 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2510 * to check if it is matched or not.
2511 */
2512 do {
2513 tid = this_cpu_read(s->cpu_slab->tid);
2514 c = raw_cpu_ptr(s->cpu_slab);
2515 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2516 unlikely(tid != READ_ONCE(c->tid)));
2517
2518 /*
2519 * Irqless object alloc/free algorithm used here depends on sequence
2520 * of fetching cpu_slab's data. tid should be fetched before anything
2521 * on c to guarantee that object and page associated with previous tid
2522 * won't be used with current tid. If we fetch tid first, object and
2523 * page could be one associated with next tid and our alloc/free
2524 * request will be failed. In this case, we will retry. So, no problem.
2525 */
2526 barrier();
2527
2528 /*
2529 * The transaction ids are globally unique per cpu and per operation on
2530 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2531 * occurs on the right processor and that there was no operation on the
2532 * linked list in between.
2533 */
2534
2535 object = c->freelist;
2536 page = c->page;
2537 if (unlikely(!object || !node_match(page, node))) {
2538 object = __slab_alloc(s, gfpflags, node, addr, c);
2539 stat(s, ALLOC_SLOWPATH);
2540 } else {
2541 void *next_object = get_freepointer_safe(s, object);
2542
2543 /*
2544 * The cmpxchg will only match if there was no additional
2545 * operation and if we are on the right processor.
2546 *
2547 * The cmpxchg does the following atomically (without lock
2548 * semantics!)
2549 * 1. Relocate first pointer to the current per cpu area.
2550 * 2. Verify that tid and freelist have not been changed
2551 * 3. If they were not changed replace tid and freelist
2552 *
2553 * Since this is without lock semantics the protection is only
2554 * against code executing on this cpu *not* from access by
2555 * other cpus.
2556 */
2557 if (unlikely(!this_cpu_cmpxchg_double(
2558 s->cpu_slab->freelist, s->cpu_slab->tid,
2559 object, tid,
2560 next_object, next_tid(tid)))) {
2561
2562 note_cmpxchg_failure("slab_alloc", s, tid);
2563 goto redo;
2564 }
2565 prefetch_freepointer(s, next_object);
2566 stat(s, ALLOC_FASTPATH);
2567 }
2568
2569 if (unlikely(gfpflags & __GFP_ZERO) && object)
2570 memset(object, 0, s->object_size);
2571
2572 slab_post_alloc_hook(s, gfpflags, 1, &object);
2573
2574 return object;
2575}
2576
2577static __always_inline void *slab_alloc(struct kmem_cache *s,
2578 gfp_t gfpflags, unsigned long addr)
2579{
2580 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2581}
2582
2583void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2584{
2585 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2586
2587 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2588 s->size, gfpflags);
2589
2590 return ret;
2591}
2592EXPORT_SYMBOL(kmem_cache_alloc);
2593
2594#ifdef CONFIG_TRACING
2595void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2596{
2597 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2598 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2599 kasan_kmalloc(s, ret, size, gfpflags);
2600 return ret;
2601}
2602EXPORT_SYMBOL(kmem_cache_alloc_trace);
2603#endif
2604
2605#ifdef CONFIG_NUMA
2606void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2607{
2608 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2609
2610 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2611 s->object_size, s->size, gfpflags, node);
2612
2613 return ret;
2614}
2615EXPORT_SYMBOL(kmem_cache_alloc_node);
2616
2617#ifdef CONFIG_TRACING
2618void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2619 gfp_t gfpflags,
2620 int node, size_t size)
2621{
2622 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2623
2624 trace_kmalloc_node(_RET_IP_, ret,
2625 size, s->size, gfpflags, node);
2626
2627 kasan_kmalloc(s, ret, size, gfpflags);
2628 return ret;
2629}
2630EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2631#endif
2632#endif
2633
2634/*
2635 * Slow path handling. This may still be called frequently since objects
2636 * have a longer lifetime than the cpu slabs in most processing loads.
2637 *
2638 * So we still attempt to reduce cache line usage. Just take the slab
2639 * lock and free the item. If there is no additional partial page
2640 * handling required then we can return immediately.
2641 */
2642static void __slab_free(struct kmem_cache *s, struct page *page,
2643 void *head, void *tail, int cnt,
2644 unsigned long addr)
2645
2646{
2647 void *prior;
2648 int was_frozen;
2649 struct page new;
2650 unsigned long counters;
2651 struct kmem_cache_node *n = NULL;
2652 unsigned long uninitialized_var(flags);
2653
2654 stat(s, FREE_SLOWPATH);
2655
2656 if (kmem_cache_debug(s) &&
2657 !free_debug_processing(s, page, head, tail, cnt, addr))
2658 return;
2659
2660 do {
2661 if (unlikely(n)) {
2662 spin_unlock_irqrestore(&n->list_lock, flags);
2663 n = NULL;
2664 }
2665 prior = page->freelist;
2666 counters = page->counters;
2667 set_freepointer(s, tail, prior);
2668 new.counters = counters;
2669 was_frozen = new.frozen;
2670 new.inuse -= cnt;
2671 if ((!new.inuse || !prior) && !was_frozen) {
2672
2673 if (kmem_cache_has_cpu_partial(s) && !prior) {
2674
2675 /*
2676 * Slab was on no list before and will be
2677 * partially empty
2678 * We can defer the list move and instead
2679 * freeze it.
2680 */
2681 new.frozen = 1;
2682
2683 } else { /* Needs to be taken off a list */
2684
2685 n = get_node(s, page_to_nid(page));
2686 /*
2687 * Speculatively acquire the list_lock.
2688 * If the cmpxchg does not succeed then we may
2689 * drop the list_lock without any processing.
2690 *
2691 * Otherwise the list_lock will synchronize with
2692 * other processors updating the list of slabs.
2693 */
2694 spin_lock_irqsave(&n->list_lock, flags);
2695
2696 }
2697 }
2698
2699 } while (!cmpxchg_double_slab(s, page,
2700 prior, counters,
2701 head, new.counters,
2702 "__slab_free"));
2703
2704 if (likely(!n)) {
2705
2706 /*
2707 * If we just froze the page then put it onto the
2708 * per cpu partial list.
2709 */
2710 if (new.frozen && !was_frozen) {
2711 put_cpu_partial(s, page, 1);
2712 stat(s, CPU_PARTIAL_FREE);
2713 }
2714 /*
2715 * The list lock was not taken therefore no list
2716 * activity can be necessary.
2717 */
2718 if (was_frozen)
2719 stat(s, FREE_FROZEN);
2720 return;
2721 }
2722
2723 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2724 goto slab_empty;
2725
2726 /*
2727 * Objects left in the slab. If it was not on the partial list before
2728 * then add it.
2729 */
2730 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2731 if (kmem_cache_debug(s))
2732 remove_full(s, n, page);
2733 add_partial(n, page, DEACTIVATE_TO_TAIL);
2734 stat(s, FREE_ADD_PARTIAL);
2735 }
2736 spin_unlock_irqrestore(&n->list_lock, flags);
2737 return;
2738
2739slab_empty:
2740 if (prior) {
2741 /*
2742 * Slab on the partial list.
2743 */
2744 remove_partial(n, page);
2745 stat(s, FREE_REMOVE_PARTIAL);
2746 } else {
2747 /* Slab must be on the full list */
2748 remove_full(s, n, page);
2749 }
2750
2751 spin_unlock_irqrestore(&n->list_lock, flags);
2752 stat(s, FREE_SLAB);
2753 discard_slab(s, page);
2754}
2755
2756/*
2757 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2758 * can perform fastpath freeing without additional function calls.
2759 *
2760 * The fastpath is only possible if we are freeing to the current cpu slab
2761 * of this processor. This typically the case if we have just allocated
2762 * the item before.
2763 *
2764 * If fastpath is not possible then fall back to __slab_free where we deal
2765 * with all sorts of special processing.
2766 *
2767 * Bulk free of a freelist with several objects (all pointing to the
2768 * same page) possible by specifying head and tail ptr, plus objects
2769 * count (cnt). Bulk free indicated by tail pointer being set.
2770 */
2771static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2772 void *head, void *tail, int cnt,
2773 unsigned long addr)
2774{
2775 void *tail_obj = tail ? : head;
2776 struct kmem_cache_cpu *c;
2777 unsigned long tid;
2778
2779 slab_free_freelist_hook(s, head, tail);
2780
2781redo:
2782 /*
2783 * Determine the currently cpus per cpu slab.
2784 * The cpu may change afterward. However that does not matter since
2785 * data is retrieved via this pointer. If we are on the same cpu
2786 * during the cmpxchg then the free will succeed.
2787 */
2788 do {
2789 tid = this_cpu_read(s->cpu_slab->tid);
2790 c = raw_cpu_ptr(s->cpu_slab);
2791 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2792 unlikely(tid != READ_ONCE(c->tid)));
2793
2794 /* Same with comment on barrier() in slab_alloc_node() */
2795 barrier();
2796
2797 if (likely(page == c->page)) {
2798 set_freepointer(s, tail_obj, c->freelist);
2799
2800 if (unlikely(!this_cpu_cmpxchg_double(
2801 s->cpu_slab->freelist, s->cpu_slab->tid,
2802 c->freelist, tid,
2803 head, next_tid(tid)))) {
2804
2805 note_cmpxchg_failure("slab_free", s, tid);
2806 goto redo;
2807 }
2808 stat(s, FREE_FASTPATH);
2809 } else
2810 __slab_free(s, page, head, tail_obj, cnt, addr);
2811
2812}
2813
2814void kmem_cache_free(struct kmem_cache *s, void *x)
2815{
2816 s = cache_from_obj(s, x);
2817 if (!s)
2818 return;
2819 slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
2820 trace_kmem_cache_free(_RET_IP_, x);
2821}
2822EXPORT_SYMBOL(kmem_cache_free);
2823
2824struct detached_freelist {
2825 struct page *page;
2826 void *tail;
2827 void *freelist;
2828 int cnt;
2829 struct kmem_cache *s;
2830};
2831
2832/*
2833 * This function progressively scans the array with free objects (with
2834 * a limited look ahead) and extract objects belonging to the same
2835 * page. It builds a detached freelist directly within the given
2836 * page/objects. This can happen without any need for
2837 * synchronization, because the objects are owned by running process.
2838 * The freelist is build up as a single linked list in the objects.
2839 * The idea is, that this detached freelist can then be bulk
2840 * transferred to the real freelist(s), but only requiring a single
2841 * synchronization primitive. Look ahead in the array is limited due
2842 * to performance reasons.
2843 */
2844static inline
2845int build_detached_freelist(struct kmem_cache *s, size_t size,
2846 void **p, struct detached_freelist *df)
2847{
2848 size_t first_skipped_index = 0;
2849 int lookahead = 3;
2850 void *object;
2851 struct page *page;
2852
2853 /* Always re-init detached_freelist */
2854 df->page = NULL;
2855
2856 do {
2857 object = p[--size];
2858 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
2859 } while (!object && size);
2860
2861 if (!object)
2862 return 0;
2863
2864 page = virt_to_head_page(object);
2865 if (!s) {
2866 /* Handle kalloc'ed objects */
2867 if (unlikely(!PageSlab(page))) {
2868 BUG_ON(!PageCompound(page));
2869 kfree_hook(object);
2870 __free_kmem_pages(page, compound_order(page));
2871 p[size] = NULL; /* mark object processed */
2872 return size;
2873 }
2874 /* Derive kmem_cache from object */
2875 df->s = page->slab_cache;
2876 } else {
2877 df->s = cache_from_obj(s, object); /* Support for memcg */
2878 }
2879
2880 /* Start new detached freelist */
2881 df->page = page;
2882 set_freepointer(df->s, object, NULL);
2883 df->tail = object;
2884 df->freelist = object;
2885 p[size] = NULL; /* mark object processed */
2886 df->cnt = 1;
2887
2888 while (size) {
2889 object = p[--size];
2890 if (!object)
2891 continue; /* Skip processed objects */
2892
2893 /* df->page is always set at this point */
2894 if (df->page == virt_to_head_page(object)) {
2895 /* Opportunity build freelist */
2896 set_freepointer(df->s, object, df->freelist);
2897 df->freelist = object;
2898 df->cnt++;
2899 p[size] = NULL; /* mark object processed */
2900
2901 continue;
2902 }
2903
2904 /* Limit look ahead search */
2905 if (!--lookahead)
2906 break;
2907
2908 if (!first_skipped_index)
2909 first_skipped_index = size + 1;
2910 }
2911
2912 return first_skipped_index;
2913}
2914
2915/* Note that interrupts must be enabled when calling this function. */
2916void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
2917{
2918 if (WARN_ON(!size))
2919 return;
2920
2921 do {
2922 struct detached_freelist df;
2923
2924 size = build_detached_freelist(s, size, p, &df);
2925 if (unlikely(!df.page))
2926 continue;
2927
2928 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
2929 } while (likely(size));
2930}
2931EXPORT_SYMBOL(kmem_cache_free_bulk);
2932
2933/* Note that interrupts must be enabled when calling this function. */
2934int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
2935 void **p)
2936{
2937 struct kmem_cache_cpu *c;
2938 int i;
2939
2940 /* memcg and kmem_cache debug support */
2941 s = slab_pre_alloc_hook(s, flags);
2942 if (unlikely(!s))
2943 return false;
2944 /*
2945 * Drain objects in the per cpu slab, while disabling local
2946 * IRQs, which protects against PREEMPT and interrupts
2947 * handlers invoking normal fastpath.
2948 */
2949 local_irq_disable();
2950 c = this_cpu_ptr(s->cpu_slab);
2951
2952 for (i = 0; i < size; i++) {
2953 void *object = c->freelist;
2954
2955 if (unlikely(!object)) {
2956 /*
2957 * Invoking slow path likely have side-effect
2958 * of re-populating per CPU c->freelist
2959 */
2960 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
2961 _RET_IP_, c);
2962 if (unlikely(!p[i]))
2963 goto error;
2964
2965 c = this_cpu_ptr(s->cpu_slab);
2966 continue; /* goto for-loop */
2967 }
2968 c->freelist = get_freepointer(s, object);
2969 p[i] = object;
2970 }
2971 c->tid = next_tid(c->tid);
2972 local_irq_enable();
2973
2974 /* Clear memory outside IRQ disabled fastpath loop */
2975 if (unlikely(flags & __GFP_ZERO)) {
2976 int j;
2977
2978 for (j = 0; j < i; j++)
2979 memset(p[j], 0, s->object_size);
2980 }
2981
2982 /* memcg and kmem_cache debug support */
2983 slab_post_alloc_hook(s, flags, size, p);
2984 return i;
2985error:
2986 local_irq_enable();
2987 slab_post_alloc_hook(s, flags, i, p);
2988 __kmem_cache_free_bulk(s, i, p);
2989 return 0;
2990}
2991EXPORT_SYMBOL(kmem_cache_alloc_bulk);
2992
2993
2994/*
2995 * Object placement in a slab is made very easy because we always start at
2996 * offset 0. If we tune the size of the object to the alignment then we can
2997 * get the required alignment by putting one properly sized object after
2998 * another.
2999 *
3000 * Notice that the allocation order determines the sizes of the per cpu
3001 * caches. Each processor has always one slab available for allocations.
3002 * Increasing the allocation order reduces the number of times that slabs
3003 * must be moved on and off the partial lists and is therefore a factor in
3004 * locking overhead.
3005 */
3006
3007/*
3008 * Mininum / Maximum order of slab pages. This influences locking overhead
3009 * and slab fragmentation. A higher order reduces the number of partial slabs
3010 * and increases the number of allocations possible without having to
3011 * take the list_lock.
3012 */
3013static int slub_min_order;
3014static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3015static int slub_min_objects;
3016
3017/*
3018 * Calculate the order of allocation given an slab object size.
3019 *
3020 * The order of allocation has significant impact on performance and other
3021 * system components. Generally order 0 allocations should be preferred since
3022 * order 0 does not cause fragmentation in the page allocator. Larger objects
3023 * be problematic to put into order 0 slabs because there may be too much
3024 * unused space left. We go to a higher order if more than 1/16th of the slab
3025 * would be wasted.
3026 *
3027 * In order to reach satisfactory performance we must ensure that a minimum
3028 * number of objects is in one slab. Otherwise we may generate too much
3029 * activity on the partial lists which requires taking the list_lock. This is
3030 * less a concern for large slabs though which are rarely used.
3031 *
3032 * slub_max_order specifies the order where we begin to stop considering the
3033 * number of objects in a slab as critical. If we reach slub_max_order then
3034 * we try to keep the page order as low as possible. So we accept more waste
3035 * of space in favor of a small page order.
3036 *
3037 * Higher order allocations also allow the placement of more objects in a
3038 * slab and thereby reduce object handling overhead. If the user has
3039 * requested a higher mininum order then we start with that one instead of
3040 * the smallest order which will fit the object.
3041 */
3042static inline int slab_order(int size, int min_objects,
3043 int max_order, int fract_leftover, int reserved)
3044{
3045 int order;
3046 int rem;
3047 int min_order = slub_min_order;
3048
3049 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
3050 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3051
3052 for (order = max(min_order, get_order(min_objects * size + reserved));
3053 order <= max_order; order++) {
3054
3055 unsigned long slab_size = PAGE_SIZE << order;
3056
3057 rem = (slab_size - reserved) % size;
3058
3059 if (rem <= slab_size / fract_leftover)
3060 break;
3061 }
3062
3063 return order;
3064}
3065
3066static inline int calculate_order(int size, int reserved)
3067{
3068 int order;
3069 int min_objects;
3070 int fraction;
3071 int max_objects;
3072
3073 /*
3074 * Attempt to find best configuration for a slab. This
3075 * works by first attempting to generate a layout with
3076 * the best configuration and backing off gradually.
3077 *
3078 * First we increase the acceptable waste in a slab. Then
3079 * we reduce the minimum objects required in a slab.
3080 */
3081 min_objects = slub_min_objects;
3082 if (!min_objects)
3083 min_objects = 4 * (fls(nr_cpu_ids) + 1);
3084 max_objects = order_objects(slub_max_order, size, reserved);
3085 min_objects = min(min_objects, max_objects);
3086
3087 while (min_objects > 1) {
3088 fraction = 16;
3089 while (fraction >= 4) {
3090 order = slab_order(size, min_objects,
3091 slub_max_order, fraction, reserved);
3092 if (order <= slub_max_order)
3093 return order;
3094 fraction /= 2;
3095 }
3096 min_objects--;
3097 }
3098
3099 /*
3100 * We were unable to place multiple objects in a slab. Now
3101 * lets see if we can place a single object there.
3102 */
3103 order = slab_order(size, 1, slub_max_order, 1, reserved);
3104 if (order <= slub_max_order)
3105 return order;
3106
3107 /*
3108 * Doh this slab cannot be placed using slub_max_order.
3109 */
3110 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
3111 if (order < MAX_ORDER)
3112 return order;
3113 return -ENOSYS;
3114}
3115
3116static void
3117init_kmem_cache_node(struct kmem_cache_node *n)
3118{
3119 n->nr_partial = 0;
3120 spin_lock_init(&n->list_lock);
3121 INIT_LIST_HEAD(&n->partial);
3122#ifdef CONFIG_SLUB_DEBUG
3123 atomic_long_set(&n->nr_slabs, 0);
3124 atomic_long_set(&n->total_objects, 0);
3125 INIT_LIST_HEAD(&n->full);
3126#endif
3127}
3128
3129static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3130{
3131 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3132 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3133
3134 /*
3135 * Must align to double word boundary for the double cmpxchg
3136 * instructions to work; see __pcpu_double_call_return_bool().
3137 */
3138 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3139 2 * sizeof(void *));
3140
3141 if (!s->cpu_slab)
3142 return 0;
3143
3144 init_kmem_cache_cpus(s);
3145
3146 return 1;
3147}
3148
3149static struct kmem_cache *kmem_cache_node;
3150
3151/*
3152 * No kmalloc_node yet so do it by hand. We know that this is the first
3153 * slab on the node for this slabcache. There are no concurrent accesses
3154 * possible.
3155 *
3156 * Note that this function only works on the kmem_cache_node
3157 * when allocating for the kmem_cache_node. This is used for bootstrapping
3158 * memory on a fresh node that has no slab structures yet.
3159 */
3160static void early_kmem_cache_node_alloc(int node)
3161{
3162 struct page *page;
3163 struct kmem_cache_node *n;
3164
3165 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3166
3167 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3168
3169 BUG_ON(!page);
3170 if (page_to_nid(page) != node) {
3171 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3172 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3173 }
3174
3175 n = page->freelist;
3176 BUG_ON(!n);
3177 page->freelist = get_freepointer(kmem_cache_node, n);
3178 page->inuse = 1;
3179 page->frozen = 0;
3180 kmem_cache_node->node[node] = n;
3181#ifdef CONFIG_SLUB_DEBUG
3182 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3183 init_tracking(kmem_cache_node, n);
3184#endif
3185 kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3186 GFP_KERNEL);
3187 init_kmem_cache_node(n);
3188 inc_slabs_node(kmem_cache_node, node, page->objects);
3189
3190 /*
3191 * No locks need to be taken here as it has just been
3192 * initialized and there is no concurrent access.
3193 */
3194 __add_partial(n, page, DEACTIVATE_TO_HEAD);
3195}
3196
3197static void free_kmem_cache_nodes(struct kmem_cache *s)
3198{
3199 int node;
3200 struct kmem_cache_node *n;
3201
3202 for_each_kmem_cache_node(s, node, n) {
3203 kmem_cache_free(kmem_cache_node, n);
3204 s->node[node] = NULL;
3205 }
3206}
3207
3208void __kmem_cache_release(struct kmem_cache *s)
3209{
3210 free_percpu(s->cpu_slab);
3211 free_kmem_cache_nodes(s);
3212}
3213
3214static int init_kmem_cache_nodes(struct kmem_cache *s)
3215{
3216 int node;
3217
3218 for_each_node_state(node, N_NORMAL_MEMORY) {
3219 struct kmem_cache_node *n;
3220
3221 if (slab_state == DOWN) {
3222 early_kmem_cache_node_alloc(node);
3223 continue;
3224 }
3225 n = kmem_cache_alloc_node(kmem_cache_node,
3226 GFP_KERNEL, node);
3227
3228 if (!n) {
3229 free_kmem_cache_nodes(s);
3230 return 0;
3231 }
3232
3233 s->node[node] = n;
3234 init_kmem_cache_node(n);
3235 }
3236 return 1;
3237}
3238
3239static void set_min_partial(struct kmem_cache *s, unsigned long min)
3240{
3241 if (min < MIN_PARTIAL)
3242 min = MIN_PARTIAL;
3243 else if (min > MAX_PARTIAL)
3244 min = MAX_PARTIAL;
3245 s->min_partial = min;
3246}
3247
3248/*
3249 * calculate_sizes() determines the order and the distribution of data within
3250 * a slab object.
3251 */
3252static int calculate_sizes(struct kmem_cache *s, int forced_order)
3253{
3254 unsigned long flags = s->flags;
3255 unsigned long size = s->object_size;
3256 int order;
3257
3258 /*
3259 * Round up object size to the next word boundary. We can only
3260 * place the free pointer at word boundaries and this determines
3261 * the possible location of the free pointer.
3262 */
3263 size = ALIGN(size, sizeof(void *));
3264
3265#ifdef CONFIG_SLUB_DEBUG
3266 /*
3267 * Determine if we can poison the object itself. If the user of
3268 * the slab may touch the object after free or before allocation
3269 * then we should never poison the object itself.
3270 */
3271 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
3272 !s->ctor)
3273 s->flags |= __OBJECT_POISON;
3274 else
3275 s->flags &= ~__OBJECT_POISON;
3276
3277
3278 /*
3279 * If we are Redzoning then check if there is some space between the
3280 * end of the object and the free pointer. If not then add an
3281 * additional word to have some bytes to store Redzone information.
3282 */
3283 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3284 size += sizeof(void *);
3285#endif
3286
3287 /*
3288 * With that we have determined the number of bytes in actual use
3289 * by the object. This is the potential offset to the free pointer.
3290 */
3291 s->inuse = size;
3292
3293 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
3294 s->ctor)) {
3295 /*
3296 * Relocate free pointer after the object if it is not
3297 * permitted to overwrite the first word of the object on
3298 * kmem_cache_free.
3299 *
3300 * This is the case if we do RCU, have a constructor or
3301 * destructor or are poisoning the objects.
3302 */
3303 s->offset = size;
3304 size += sizeof(void *);
3305 }
3306
3307#ifdef CONFIG_SLUB_DEBUG
3308 if (flags & SLAB_STORE_USER)
3309 /*
3310 * Need to store information about allocs and frees after
3311 * the object.
3312 */
3313 size += 2 * sizeof(struct track);
3314
3315 if (flags & SLAB_RED_ZONE) {
3316 /*
3317 * Add some empty padding so that we can catch
3318 * overwrites from earlier objects rather than let
3319 * tracking information or the free pointer be
3320 * corrupted if a user writes before the start
3321 * of the object.
3322 */
3323 size += sizeof(void *);
3324
3325 s->red_left_pad = sizeof(void *);
3326 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3327 size += s->red_left_pad;
3328 }
3329#endif
3330
3331 /*
3332 * SLUB stores one object immediately after another beginning from
3333 * offset 0. In order to align the objects we have to simply size
3334 * each object to conform to the alignment.
3335 */
3336 size = ALIGN(size, s->align);
3337 s->size = size;
3338 if (forced_order >= 0)
3339 order = forced_order;
3340 else
3341 order = calculate_order(size, s->reserved);
3342
3343 if (order < 0)
3344 return 0;
3345
3346 s->allocflags = 0;
3347 if (order)
3348 s->allocflags |= __GFP_COMP;
3349
3350 if (s->flags & SLAB_CACHE_DMA)
3351 s->allocflags |= GFP_DMA;
3352
3353 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3354 s->allocflags |= __GFP_RECLAIMABLE;
3355
3356 /*
3357 * Determine the number of objects per slab
3358 */
3359 s->oo = oo_make(order, size, s->reserved);
3360 s->min = oo_make(get_order(size), size, s->reserved);
3361 if (oo_objects(s->oo) > oo_objects(s->max))
3362 s->max = s->oo;
3363
3364 return !!oo_objects(s->oo);
3365}
3366
3367static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3368{
3369 s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3370 s->reserved = 0;
3371
3372 if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3373 s->reserved = sizeof(struct rcu_head);
3374
3375 if (!calculate_sizes(s, -1))
3376 goto error;
3377 if (disable_higher_order_debug) {
3378 /*
3379 * Disable debugging flags that store metadata if the min slab
3380 * order increased.
3381 */
3382 if (get_order(s->size) > get_order(s->object_size)) {
3383 s->flags &= ~DEBUG_METADATA_FLAGS;
3384 s->offset = 0;
3385 if (!calculate_sizes(s, -1))
3386 goto error;
3387 }
3388 }
3389
3390#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3391 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3392 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3393 /* Enable fast mode */
3394 s->flags |= __CMPXCHG_DOUBLE;
3395#endif
3396
3397 /*
3398 * The larger the object size is, the more pages we want on the partial
3399 * list to avoid pounding the page allocator excessively.
3400 */
3401 set_min_partial(s, ilog2(s->size) / 2);
3402
3403 /*
3404 * cpu_partial determined the maximum number of objects kept in the
3405 * per cpu partial lists of a processor.
3406 *
3407 * Per cpu partial lists mainly contain slabs that just have one
3408 * object freed. If they are used for allocation then they can be
3409 * filled up again with minimal effort. The slab will never hit the
3410 * per node partial lists and therefore no locking will be required.
3411 *
3412 * This setting also determines
3413 *
3414 * A) The number of objects from per cpu partial slabs dumped to the
3415 * per node list when we reach the limit.
3416 * B) The number of objects in cpu partial slabs to extract from the
3417 * per node list when we run out of per cpu objects. We only fetch
3418 * 50% to keep some capacity around for frees.
3419 */
3420 if (!kmem_cache_has_cpu_partial(s))
3421 s->cpu_partial = 0;
3422 else if (s->size >= PAGE_SIZE)
3423 s->cpu_partial = 2;
3424 else if (s->size >= 1024)
3425 s->cpu_partial = 6;
3426 else if (s->size >= 256)
3427 s->cpu_partial = 13;
3428 else
3429 s->cpu_partial = 30;
3430
3431#ifdef CONFIG_NUMA
3432 s->remote_node_defrag_ratio = 1000;
3433#endif
3434 if (!init_kmem_cache_nodes(s))
3435 goto error;
3436
3437 if (alloc_kmem_cache_cpus(s))
3438 return 0;
3439
3440 free_kmem_cache_nodes(s);
3441error:
3442 if (flags & SLAB_PANIC)
3443 panic("Cannot create slab %s size=%lu realsize=%u order=%u offset=%u flags=%lx\n",
3444 s->name, (unsigned long)s->size, s->size,
3445 oo_order(s->oo), s->offset, flags);
3446 return -EINVAL;
3447}
3448
3449static void list_slab_objects(struct kmem_cache *s, struct page *page,
3450 const char *text)
3451{
3452#ifdef CONFIG_SLUB_DEBUG
3453 void *addr = page_address(page);
3454 void *p;
3455 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3456 sizeof(long), GFP_ATOMIC);
3457 if (!map)
3458 return;
3459 slab_err(s, page, text, s->name);
3460 slab_lock(page);
3461
3462 get_map(s, page, map);
3463 for_each_object(p, s, addr, page->objects) {
3464
3465 if (!test_bit(slab_index(p, s, addr), map)) {
3466 pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3467 print_tracking(s, p);
3468 }
3469 }
3470 slab_unlock(page);
3471 kfree(map);
3472#endif
3473}
3474
3475/*
3476 * Attempt to free all partial slabs on a node.
3477 * This is called from __kmem_cache_shutdown(). We must take list_lock
3478 * because sysfs file might still access partial list after the shutdowning.
3479 */
3480static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3481{
3482 struct page *page, *h;
3483
3484 BUG_ON(irqs_disabled());
3485 spin_lock_irq(&n->list_lock);
3486 list_for_each_entry_safe(page, h, &n->partial, lru) {
3487 if (!page->inuse) {
3488 remove_partial(n, page);
3489 discard_slab(s, page);
3490 } else {
3491 list_slab_objects(s, page,
3492 "Objects remaining in %s on __kmem_cache_shutdown()");
3493 }
3494 }
3495 spin_unlock_irq(&n->list_lock);
3496}
3497
3498/*
3499 * Release all resources used by a slab cache.
3500 */
3501int __kmem_cache_shutdown(struct kmem_cache *s)
3502{
3503 int node;
3504 struct kmem_cache_node *n;
3505
3506 flush_all(s);
3507 /* Attempt to free all objects */
3508 for_each_kmem_cache_node(s, node, n) {
3509 free_partial(s, n);
3510 if (n->nr_partial || slabs_node(s, node))
3511 return 1;
3512 }
3513 return 0;
3514}
3515
3516/********************************************************************
3517 * Kmalloc subsystem
3518 *******************************************************************/
3519
3520static int __init setup_slub_min_order(char *str)
3521{
3522 get_option(&str, &slub_min_order);
3523
3524 return 1;
3525}
3526
3527__setup("slub_min_order=", setup_slub_min_order);
3528
3529static int __init setup_slub_max_order(char *str)
3530{
3531 get_option(&str, &slub_max_order);
3532 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3533
3534 return 1;
3535}
3536
3537__setup("slub_max_order=", setup_slub_max_order);
3538
3539static int __init setup_slub_min_objects(char *str)
3540{
3541 get_option(&str, &slub_min_objects);
3542
3543 return 1;
3544}
3545
3546__setup("slub_min_objects=", setup_slub_min_objects);
3547
3548void *__kmalloc(size_t size, gfp_t flags)
3549{
3550 struct kmem_cache *s;
3551 void *ret;
3552
3553 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3554 return kmalloc_large(size, flags);
3555
3556 s = kmalloc_slab(size, flags);
3557
3558 if (unlikely(ZERO_OR_NULL_PTR(s)))
3559 return s;
3560
3561 ret = slab_alloc(s, flags, _RET_IP_);
3562
3563 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3564
3565 kasan_kmalloc(s, ret, size, flags);
3566
3567 return ret;
3568}
3569EXPORT_SYMBOL(__kmalloc);
3570
3571#ifdef CONFIG_NUMA
3572static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3573{
3574 struct page *page;
3575 void *ptr = NULL;
3576
3577 flags |= __GFP_COMP | __GFP_NOTRACK;
3578 page = alloc_kmem_pages_node(node, flags, get_order(size));
3579 if (page)
3580 ptr = page_address(page);
3581
3582 kmalloc_large_node_hook(ptr, size, flags);
3583 return ptr;
3584}
3585
3586void *__kmalloc_node(size_t size, gfp_t flags, int node)
3587{
3588 struct kmem_cache *s;
3589 void *ret;
3590
3591 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3592 ret = kmalloc_large_node(size, flags, node);
3593
3594 trace_kmalloc_node(_RET_IP_, ret,
3595 size, PAGE_SIZE << get_order(size),
3596 flags, node);
3597
3598 return ret;
3599 }
3600
3601 s = kmalloc_slab(size, flags);
3602
3603 if (unlikely(ZERO_OR_NULL_PTR(s)))
3604 return s;
3605
3606 ret = slab_alloc_node(s, flags, node, _RET_IP_);
3607
3608 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3609
3610 kasan_kmalloc(s, ret, size, flags);
3611
3612 return ret;
3613}
3614EXPORT_SYMBOL(__kmalloc_node);
3615#endif
3616
3617static size_t __ksize(const void *object)
3618{
3619 struct page *page;
3620
3621 if (unlikely(object == ZERO_SIZE_PTR))
3622 return 0;
3623
3624 page = virt_to_head_page(object);
3625
3626 if (unlikely(!PageSlab(page))) {
3627 WARN_ON(!PageCompound(page));
3628 return PAGE_SIZE << compound_order(page);
3629 }
3630
3631 return slab_ksize(page->slab_cache);
3632}
3633
3634size_t ksize(const void *object)
3635{
3636 size_t size = __ksize(object);
3637 /* We assume that ksize callers could use whole allocated area,
3638 so we need unpoison this area. */
3639 kasan_krealloc(object, size, GFP_NOWAIT);
3640 return size;
3641}
3642EXPORT_SYMBOL(ksize);
3643
3644void kfree(const void *x)
3645{
3646 struct page *page;
3647 void *object = (void *)x;
3648
3649 trace_kfree(_RET_IP_, x);
3650
3651 if (unlikely(ZERO_OR_NULL_PTR(x)))
3652 return;
3653
3654 page = virt_to_head_page(x);
3655 if (unlikely(!PageSlab(page))) {
3656 BUG_ON(!PageCompound(page));
3657 kfree_hook(x);
3658 __free_kmem_pages(page, compound_order(page));
3659 return;
3660 }
3661 slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3662}
3663EXPORT_SYMBOL(kfree);
3664
3665#define SHRINK_PROMOTE_MAX 32
3666
3667/*
3668 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3669 * up most to the head of the partial lists. New allocations will then
3670 * fill those up and thus they can be removed from the partial lists.
3671 *
3672 * The slabs with the least items are placed last. This results in them
3673 * being allocated from last increasing the chance that the last objects
3674 * are freed in them.
3675 */
3676int __kmem_cache_shrink(struct kmem_cache *s, bool deactivate)
3677{
3678 int node;
3679 int i;
3680 struct kmem_cache_node *n;
3681 struct page *page;
3682 struct page *t;
3683 struct list_head discard;
3684 struct list_head promote[SHRINK_PROMOTE_MAX];
3685 unsigned long flags;
3686 int ret = 0;
3687
3688 if (deactivate) {
3689 /*
3690 * Disable empty slabs caching. Used to avoid pinning offline
3691 * memory cgroups by kmem pages that can be freed.
3692 */
3693 s->cpu_partial = 0;
3694 s->min_partial = 0;
3695
3696 /*
3697 * s->cpu_partial is checked locklessly (see put_cpu_partial),
3698 * so we have to make sure the change is visible.
3699 */
3700 kick_all_cpus_sync();
3701 }
3702
3703 flush_all(s);
3704 for_each_kmem_cache_node(s, node, n) {
3705 INIT_LIST_HEAD(&discard);
3706 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3707 INIT_LIST_HEAD(promote + i);
3708
3709 spin_lock_irqsave(&n->list_lock, flags);
3710
3711 /*
3712 * Build lists of slabs to discard or promote.
3713 *
3714 * Note that concurrent frees may occur while we hold the
3715 * list_lock. page->inuse here is the upper limit.
3716 */
3717 list_for_each_entry_safe(page, t, &n->partial, lru) {
3718 int free = page->objects - page->inuse;
3719
3720 /* Do not reread page->inuse */
3721 barrier();
3722
3723 /* We do not keep full slabs on the list */
3724 BUG_ON(free <= 0);
3725
3726 if (free == page->objects) {
3727 list_move(&page->lru, &discard);
3728 n->nr_partial--;
3729 } else if (free <= SHRINK_PROMOTE_MAX)
3730 list_move(&page->lru, promote + free - 1);
3731 }
3732
3733 /*
3734 * Promote the slabs filled up most to the head of the
3735 * partial list.
3736 */
3737 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
3738 list_splice(promote + i, &n->partial);
3739
3740 spin_unlock_irqrestore(&n->list_lock, flags);
3741
3742 /* Release empty slabs */
3743 list_for_each_entry_safe(page, t, &discard, lru)
3744 discard_slab(s, page);
3745
3746 if (slabs_node(s, node))
3747 ret = 1;
3748 }
3749
3750 return ret;
3751}
3752
3753static int slab_mem_going_offline_callback(void *arg)
3754{
3755 struct kmem_cache *s;
3756
3757 mutex_lock(&slab_mutex);
3758 list_for_each_entry(s, &slab_caches, list)
3759 __kmem_cache_shrink(s, false);
3760 mutex_unlock(&slab_mutex);
3761
3762 return 0;
3763}
3764
3765static void slab_mem_offline_callback(void *arg)
3766{
3767 struct kmem_cache_node *n;
3768 struct kmem_cache *s;
3769 struct memory_notify *marg = arg;
3770 int offline_node;
3771
3772 offline_node = marg->status_change_nid_normal;
3773
3774 /*
3775 * If the node still has available memory. we need kmem_cache_node
3776 * for it yet.
3777 */
3778 if (offline_node < 0)
3779 return;
3780
3781 mutex_lock(&slab_mutex);
3782 list_for_each_entry(s, &slab_caches, list) {
3783 n = get_node(s, offline_node);
3784 if (n) {
3785 /*
3786 * if n->nr_slabs > 0, slabs still exist on the node
3787 * that is going down. We were unable to free them,
3788 * and offline_pages() function shouldn't call this
3789 * callback. So, we must fail.
3790 */
3791 BUG_ON(slabs_node(s, offline_node));
3792
3793 s->node[offline_node] = NULL;
3794 kmem_cache_free(kmem_cache_node, n);
3795 }
3796 }
3797 mutex_unlock(&slab_mutex);
3798}
3799
3800static int slab_mem_going_online_callback(void *arg)
3801{
3802 struct kmem_cache_node *n;
3803 struct kmem_cache *s;
3804 struct memory_notify *marg = arg;
3805 int nid = marg->status_change_nid_normal;
3806 int ret = 0;
3807
3808 /*
3809 * If the node's memory is already available, then kmem_cache_node is
3810 * already created. Nothing to do.
3811 */
3812 if (nid < 0)
3813 return 0;
3814
3815 /*
3816 * We are bringing a node online. No memory is available yet. We must
3817 * allocate a kmem_cache_node structure in order to bring the node
3818 * online.
3819 */
3820 mutex_lock(&slab_mutex);
3821 list_for_each_entry(s, &slab_caches, list) {
3822 /*
3823 * XXX: kmem_cache_alloc_node will fallback to other nodes
3824 * since memory is not yet available from the node that
3825 * is brought up.
3826 */
3827 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3828 if (!n) {
3829 ret = -ENOMEM;
3830 goto out;
3831 }
3832 init_kmem_cache_node(n);
3833 s->node[nid] = n;
3834 }
3835out:
3836 mutex_unlock(&slab_mutex);
3837 return ret;
3838}
3839
3840static int slab_memory_callback(struct notifier_block *self,
3841 unsigned long action, void *arg)
3842{
3843 int ret = 0;
3844
3845 switch (action) {
3846 case MEM_GOING_ONLINE:
3847 ret = slab_mem_going_online_callback(arg);
3848 break;
3849 case MEM_GOING_OFFLINE:
3850 ret = slab_mem_going_offline_callback(arg);
3851 break;
3852 case MEM_OFFLINE:
3853 case MEM_CANCEL_ONLINE:
3854 slab_mem_offline_callback(arg);
3855 break;
3856 case MEM_ONLINE:
3857 case MEM_CANCEL_OFFLINE:
3858 break;
3859 }
3860 if (ret)
3861 ret = notifier_from_errno(ret);
3862 else
3863 ret = NOTIFY_OK;
3864 return ret;
3865}
3866
3867static struct notifier_block slab_memory_callback_nb = {
3868 .notifier_call = slab_memory_callback,
3869 .priority = SLAB_CALLBACK_PRI,
3870};
3871
3872/********************************************************************
3873 * Basic setup of slabs
3874 *******************************************************************/
3875
3876/*
3877 * Used for early kmem_cache structures that were allocated using
3878 * the page allocator. Allocate them properly then fix up the pointers
3879 * that may be pointing to the wrong kmem_cache structure.
3880 */
3881
3882static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
3883{
3884 int node;
3885 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
3886 struct kmem_cache_node *n;
3887
3888 memcpy(s, static_cache, kmem_cache->object_size);
3889
3890 /*
3891 * This runs very early, and only the boot processor is supposed to be
3892 * up. Even if it weren't true, IRQs are not up so we couldn't fire
3893 * IPIs around.
3894 */
3895 __flush_cpu_slab(s, smp_processor_id());
3896 for_each_kmem_cache_node(s, node, n) {
3897 struct page *p;
3898
3899 list_for_each_entry(p, &n->partial, lru)
3900 p->slab_cache = s;
3901
3902#ifdef CONFIG_SLUB_DEBUG
3903 list_for_each_entry(p, &n->full, lru)
3904 p->slab_cache = s;
3905#endif
3906 }
3907 slab_init_memcg_params(s);
3908 list_add(&s->list, &slab_caches);
3909 return s;
3910}
3911
3912void __init kmem_cache_init(void)
3913{
3914 static __initdata struct kmem_cache boot_kmem_cache,
3915 boot_kmem_cache_node;
3916
3917 if (debug_guardpage_minorder())
3918 slub_max_order = 0;
3919
3920 kmem_cache_node = &boot_kmem_cache_node;
3921 kmem_cache = &boot_kmem_cache;
3922
3923 create_boot_cache(kmem_cache_node, "kmem_cache_node",
3924 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
3925
3926 register_hotmemory_notifier(&slab_memory_callback_nb);
3927
3928 /* Able to allocate the per node structures */
3929 slab_state = PARTIAL;
3930
3931 create_boot_cache(kmem_cache, "kmem_cache",
3932 offsetof(struct kmem_cache, node) +
3933 nr_node_ids * sizeof(struct kmem_cache_node *),
3934 SLAB_HWCACHE_ALIGN);
3935
3936 kmem_cache = bootstrap(&boot_kmem_cache);
3937
3938 /*
3939 * Allocate kmem_cache_node properly from the kmem_cache slab.
3940 * kmem_cache_node is separately allocated so no need to
3941 * update any list pointers.
3942 */
3943 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
3944
3945 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3946 setup_kmalloc_cache_index_table();
3947 create_kmalloc_caches(0);
3948
3949#ifdef CONFIG_SMP
3950 register_cpu_notifier(&slab_notifier);
3951#endif
3952
3953 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
3954 cache_line_size(),
3955 slub_min_order, slub_max_order, slub_min_objects,
3956 nr_cpu_ids, nr_node_ids);
3957}
3958
3959void __init kmem_cache_init_late(void)
3960{
3961}
3962
3963struct kmem_cache *
3964__kmem_cache_alias(const char *name, size_t size, size_t align,
3965 unsigned long flags, void (*ctor)(void *))
3966{
3967 struct kmem_cache *s, *c;
3968
3969 s = find_mergeable(size, align, flags, name, ctor);
3970 if (s) {
3971 s->refcount++;
3972
3973 /*
3974 * Adjust the object sizes so that we clear
3975 * the complete object on kzalloc.
3976 */
3977 s->object_size = max(s->object_size, (int)size);
3978 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3979
3980 for_each_memcg_cache(c, s) {
3981 c->object_size = s->object_size;
3982 c->inuse = max_t(int, c->inuse,
3983 ALIGN(size, sizeof(void *)));
3984 }
3985
3986 if (sysfs_slab_alias(s, name)) {
3987 s->refcount--;
3988 s = NULL;
3989 }
3990 }
3991
3992 return s;
3993}
3994
3995int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
3996{
3997 int err;
3998
3999 err = kmem_cache_open(s, flags);
4000 if (err)
4001 return err;
4002
4003 /* Mutex is not taken during early boot */
4004 if (slab_state <= UP)
4005 return 0;
4006
4007 memcg_propagate_slab_attrs(s);
4008 err = sysfs_slab_add(s);
4009 if (err)
4010 __kmem_cache_release(s);
4011
4012 return err;
4013}
4014
4015#ifdef CONFIG_SMP
4016/*
4017 * Use the cpu notifier to insure that the cpu slabs are flushed when
4018 * necessary.
4019 */
4020static int slab_cpuup_callback(struct notifier_block *nfb,
4021 unsigned long action, void *hcpu)
4022{
4023 long cpu = (long)hcpu;
4024 struct kmem_cache *s;
4025 unsigned long flags;
4026
4027 switch (action) {
4028 case CPU_UP_CANCELED:
4029 case CPU_UP_CANCELED_FROZEN:
4030 case CPU_DEAD:
4031 case CPU_DEAD_FROZEN:
4032 mutex_lock(&slab_mutex);
4033 list_for_each_entry(s, &slab_caches, list) {
4034 local_irq_save(flags);
4035 __flush_cpu_slab(s, cpu);
4036 local_irq_restore(flags);
4037 }
4038 mutex_unlock(&slab_mutex);
4039 break;
4040 default:
4041 break;
4042 }
4043 return NOTIFY_OK;
4044}
4045
4046static struct notifier_block slab_notifier = {
4047 .notifier_call = slab_cpuup_callback
4048};
4049
4050#endif
4051
4052void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4053{
4054 struct kmem_cache *s;
4055 void *ret;
4056
4057 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4058 return kmalloc_large(size, gfpflags);
4059
4060 s = kmalloc_slab(size, gfpflags);
4061
4062 if (unlikely(ZERO_OR_NULL_PTR(s)))
4063 return s;
4064
4065 ret = slab_alloc(s, gfpflags, caller);
4066
4067 /* Honor the call site pointer we received. */
4068 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4069
4070 return ret;
4071}
4072
4073#ifdef CONFIG_NUMA
4074void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4075 int node, unsigned long caller)
4076{
4077 struct kmem_cache *s;
4078 void *ret;
4079
4080 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4081 ret = kmalloc_large_node(size, gfpflags, node);
4082
4083 trace_kmalloc_node(caller, ret,
4084 size, PAGE_SIZE << get_order(size),
4085 gfpflags, node);
4086
4087 return ret;
4088 }
4089
4090 s = kmalloc_slab(size, gfpflags);
4091
4092 if (unlikely(ZERO_OR_NULL_PTR(s)))
4093 return s;
4094
4095 ret = slab_alloc_node(s, gfpflags, node, caller);
4096
4097 /* Honor the call site pointer we received. */
4098 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4099
4100 return ret;
4101}
4102#endif
4103
4104#ifdef CONFIG_SYSFS
4105static int count_inuse(struct page *page)
4106{
4107 return page->inuse;
4108}
4109
4110static int count_total(struct page *page)
4111{
4112 return page->objects;
4113}
4114#endif
4115
4116#ifdef CONFIG_SLUB_DEBUG
4117static int validate_slab(struct kmem_cache *s, struct page *page,
4118 unsigned long *map)
4119{
4120 void *p;
4121 void *addr = page_address(page);
4122
4123 if (!check_slab(s, page) ||
4124 !on_freelist(s, page, NULL))
4125 return 0;
4126
4127 /* Now we know that a valid freelist exists */
4128 bitmap_zero(map, page->objects);
4129
4130 get_map(s, page, map);
4131 for_each_object(p, s, addr, page->objects) {
4132 if (test_bit(slab_index(p, s, addr), map))
4133 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4134 return 0;
4135 }
4136
4137 for_each_object(p, s, addr, page->objects)
4138 if (!test_bit(slab_index(p, s, addr), map))
4139 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4140 return 0;
4141 return 1;
4142}
4143
4144static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4145 unsigned long *map)
4146{
4147 slab_lock(page);
4148 validate_slab(s, page, map);
4149 slab_unlock(page);
4150}
4151
4152static int validate_slab_node(struct kmem_cache *s,
4153 struct kmem_cache_node *n, unsigned long *map)
4154{
4155 unsigned long count = 0;
4156 struct page *page;
4157 unsigned long flags;
4158
4159 spin_lock_irqsave(&n->list_lock, flags);
4160
4161 list_for_each_entry(page, &n->partial, lru) {
4162 validate_slab_slab(s, page, map);
4163 count++;
4164 }
4165 if (count != n->nr_partial)
4166 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4167 s->name, count, n->nr_partial);
4168
4169 if (!(s->flags & SLAB_STORE_USER))
4170 goto out;
4171
4172 list_for_each_entry(page, &n->full, lru) {
4173 validate_slab_slab(s, page, map);
4174 count++;
4175 }
4176 if (count != atomic_long_read(&n->nr_slabs))
4177 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4178 s->name, count, atomic_long_read(&n->nr_slabs));
4179
4180out:
4181 spin_unlock_irqrestore(&n->list_lock, flags);
4182 return count;
4183}
4184
4185static long validate_slab_cache(struct kmem_cache *s)
4186{
4187 int node;
4188 unsigned long count = 0;
4189 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4190 sizeof(unsigned long), GFP_KERNEL);
4191 struct kmem_cache_node *n;
4192
4193 if (!map)
4194 return -ENOMEM;
4195
4196 flush_all(s);
4197 for_each_kmem_cache_node(s, node, n)
4198 count += validate_slab_node(s, n, map);
4199 kfree(map);
4200 return count;
4201}
4202/*
4203 * Generate lists of code addresses where slabcache objects are allocated
4204 * and freed.
4205 */
4206
4207struct location {
4208 unsigned long count;
4209 unsigned long addr;
4210 long long sum_time;
4211 long min_time;
4212 long max_time;
4213 long min_pid;
4214 long max_pid;
4215 DECLARE_BITMAP(cpus, NR_CPUS);
4216 nodemask_t nodes;
4217};
4218
4219struct loc_track {
4220 unsigned long max;
4221 unsigned long count;
4222 struct location *loc;
4223};
4224
4225static void free_loc_track(struct loc_track *t)
4226{
4227 if (t->max)
4228 free_pages((unsigned long)t->loc,
4229 get_order(sizeof(struct location) * t->max));
4230}
4231
4232static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4233{
4234 struct location *l;
4235 int order;
4236
4237 order = get_order(sizeof(struct location) * max);
4238
4239 l = (void *)__get_free_pages(flags, order);
4240 if (!l)
4241 return 0;
4242
4243 if (t->count) {
4244 memcpy(l, t->loc, sizeof(struct location) * t->count);
4245 free_loc_track(t);
4246 }
4247 t->max = max;
4248 t->loc = l;
4249 return 1;
4250}
4251
4252static int add_location(struct loc_track *t, struct kmem_cache *s,
4253 const struct track *track)
4254{
4255 long start, end, pos;
4256 struct location *l;
4257 unsigned long caddr;
4258 unsigned long age = jiffies - track->when;
4259
4260 start = -1;
4261 end = t->count;
4262
4263 for ( ; ; ) {
4264 pos = start + (end - start + 1) / 2;
4265
4266 /*
4267 * There is nothing at "end". If we end up there
4268 * we need to add something to before end.
4269 */
4270 if (pos == end)
4271 break;
4272
4273 caddr = t->loc[pos].addr;
4274 if (track->addr == caddr) {
4275
4276 l = &t->loc[pos];
4277 l->count++;
4278 if (track->when) {
4279 l->sum_time += age;
4280 if (age < l->min_time)
4281 l->min_time = age;
4282 if (age > l->max_time)
4283 l->max_time = age;
4284
4285 if (track->pid < l->min_pid)
4286 l->min_pid = track->pid;
4287 if (track->pid > l->max_pid)
4288 l->max_pid = track->pid;
4289
4290 cpumask_set_cpu(track->cpu,
4291 to_cpumask(l->cpus));
4292 }
4293 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4294 return 1;
4295 }
4296
4297 if (track->addr < caddr)
4298 end = pos;
4299 else
4300 start = pos;
4301 }
4302
4303 /*
4304 * Not found. Insert new tracking element.
4305 */
4306 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4307 return 0;
4308
4309 l = t->loc + pos;
4310 if (pos < t->count)
4311 memmove(l + 1, l,
4312 (t->count - pos) * sizeof(struct location));
4313 t->count++;
4314 l->count = 1;
4315 l->addr = track->addr;
4316 l->sum_time = age;
4317 l->min_time = age;
4318 l->max_time = age;
4319 l->min_pid = track->pid;
4320 l->max_pid = track->pid;
4321 cpumask_clear(to_cpumask(l->cpus));
4322 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4323 nodes_clear(l->nodes);
4324 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4325 return 1;
4326}
4327
4328static void process_slab(struct loc_track *t, struct kmem_cache *s,
4329 struct page *page, enum track_item alloc,
4330 unsigned long *map)
4331{
4332 void *addr = page_address(page);
4333 void *p;
4334
4335 bitmap_zero(map, page->objects);
4336 get_map(s, page, map);
4337
4338 for_each_object(p, s, addr, page->objects)
4339 if (!test_bit(slab_index(p, s, addr), map))
4340 add_location(t, s, get_track(s, p, alloc));
4341}
4342
4343static int list_locations(struct kmem_cache *s, char *buf,
4344 enum track_item alloc)
4345{
4346 int len = 0;
4347 unsigned long i;
4348 struct loc_track t = { 0, 0, NULL };
4349 int node;
4350 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4351 sizeof(unsigned long), GFP_KERNEL);
4352 struct kmem_cache_node *n;
4353
4354 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4355 GFP_TEMPORARY)) {
4356 kfree(map);
4357 return sprintf(buf, "Out of memory\n");
4358 }
4359 /* Push back cpu slabs */
4360 flush_all(s);
4361
4362 for_each_kmem_cache_node(s, node, n) {
4363 unsigned long flags;
4364 struct page *page;
4365
4366 if (!atomic_long_read(&n->nr_slabs))
4367 continue;
4368
4369 spin_lock_irqsave(&n->list_lock, flags);
4370 list_for_each_entry(page, &n->partial, lru)
4371 process_slab(&t, s, page, alloc, map);
4372 list_for_each_entry(page, &n->full, lru)
4373 process_slab(&t, s, page, alloc, map);
4374 spin_unlock_irqrestore(&n->list_lock, flags);
4375 }
4376
4377 for (i = 0; i < t.count; i++) {
4378 struct location *l = &t.loc[i];
4379
4380 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4381 break;
4382 len += sprintf(buf + len, "%7ld ", l->count);
4383
4384 if (l->addr)
4385 len += sprintf(buf + len, "%pS", (void *)l->addr);
4386 else
4387 len += sprintf(buf + len, "<not-available>");
4388
4389 if (l->sum_time != l->min_time) {
4390 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4391 l->min_time,
4392 (long)div_u64(l->sum_time, l->count),
4393 l->max_time);
4394 } else
4395 len += sprintf(buf + len, " age=%ld",
4396 l->min_time);
4397
4398 if (l->min_pid != l->max_pid)
4399 len += sprintf(buf + len, " pid=%ld-%ld",
4400 l->min_pid, l->max_pid);
4401 else
4402 len += sprintf(buf + len, " pid=%ld",
4403 l->min_pid);
4404
4405 if (num_online_cpus() > 1 &&
4406 !cpumask_empty(to_cpumask(l->cpus)) &&
4407 len < PAGE_SIZE - 60)
4408 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4409 " cpus=%*pbl",
4410 cpumask_pr_args(to_cpumask(l->cpus)));
4411
4412 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4413 len < PAGE_SIZE - 60)
4414 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4415 " nodes=%*pbl",
4416 nodemask_pr_args(&l->nodes));
4417
4418 len += sprintf(buf + len, "\n");
4419 }
4420
4421 free_loc_track(&t);
4422 kfree(map);
4423 if (!t.count)
4424 len += sprintf(buf, "No data\n");
4425 return len;
4426}
4427#endif
4428
4429#ifdef SLUB_RESILIENCY_TEST
4430static void __init resiliency_test(void)
4431{
4432 u8 *p;
4433
4434 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4435
4436 pr_err("SLUB resiliency testing\n");
4437 pr_err("-----------------------\n");
4438 pr_err("A. Corruption after allocation\n");
4439
4440 p = kzalloc(16, GFP_KERNEL);
4441 p[16] = 0x12;
4442 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4443 p + 16);
4444
4445 validate_slab_cache(kmalloc_caches[4]);
4446
4447 /* Hmmm... The next two are dangerous */
4448 p = kzalloc(32, GFP_KERNEL);
4449 p[32 + sizeof(void *)] = 0x34;
4450 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4451 p);
4452 pr_err("If allocated object is overwritten then not detectable\n\n");
4453
4454 validate_slab_cache(kmalloc_caches[5]);
4455 p = kzalloc(64, GFP_KERNEL);
4456 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4457 *p = 0x56;
4458 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4459 p);
4460 pr_err("If allocated object is overwritten then not detectable\n\n");
4461 validate_slab_cache(kmalloc_caches[6]);
4462
4463 pr_err("\nB. Corruption after free\n");
4464 p = kzalloc(128, GFP_KERNEL);
4465 kfree(p);
4466 *p = 0x78;
4467 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4468 validate_slab_cache(kmalloc_caches[7]);
4469
4470 p = kzalloc(256, GFP_KERNEL);
4471 kfree(p);
4472 p[50] = 0x9a;
4473 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4474 validate_slab_cache(kmalloc_caches[8]);
4475
4476 p = kzalloc(512, GFP_KERNEL);
4477 kfree(p);
4478 p[512] = 0xab;
4479 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4480 validate_slab_cache(kmalloc_caches[9]);
4481}
4482#else
4483#ifdef CONFIG_SYSFS
4484static void resiliency_test(void) {};
4485#endif
4486#endif
4487
4488#ifdef CONFIG_SYSFS
4489enum slab_stat_type {
4490 SL_ALL, /* All slabs */
4491 SL_PARTIAL, /* Only partially allocated slabs */
4492 SL_CPU, /* Only slabs used for cpu caches */
4493 SL_OBJECTS, /* Determine allocated objects not slabs */
4494 SL_TOTAL /* Determine object capacity not slabs */
4495};
4496
4497#define SO_ALL (1 << SL_ALL)
4498#define SO_PARTIAL (1 << SL_PARTIAL)
4499#define SO_CPU (1 << SL_CPU)
4500#define SO_OBJECTS (1 << SL_OBJECTS)
4501#define SO_TOTAL (1 << SL_TOTAL)
4502
4503static ssize_t show_slab_objects(struct kmem_cache *s,
4504 char *buf, unsigned long flags)
4505{
4506 unsigned long total = 0;
4507 int node;
4508 int x;
4509 unsigned long *nodes;
4510
4511 nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4512 if (!nodes)
4513 return -ENOMEM;
4514
4515 if (flags & SO_CPU) {
4516 int cpu;
4517
4518 for_each_possible_cpu(cpu) {
4519 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4520 cpu);
4521 int node;
4522 struct page *page;
4523
4524 page = READ_ONCE(c->page);
4525 if (!page)
4526 continue;
4527
4528 node = page_to_nid(page);
4529 if (flags & SO_TOTAL)
4530 x = page->objects;
4531 else if (flags & SO_OBJECTS)
4532 x = page->inuse;
4533 else
4534 x = 1;
4535
4536 total += x;
4537 nodes[node] += x;
4538
4539 page = READ_ONCE(c->partial);
4540 if (page) {
4541 node = page_to_nid(page);
4542 if (flags & SO_TOTAL)
4543 WARN_ON_ONCE(1);
4544 else if (flags & SO_OBJECTS)
4545 WARN_ON_ONCE(1);
4546 else
4547 x = page->pages;
4548 total += x;
4549 nodes[node] += x;
4550 }
4551 }
4552 }
4553
4554 get_online_mems();
4555#ifdef CONFIG_SLUB_DEBUG
4556 if (flags & SO_ALL) {
4557 struct kmem_cache_node *n;
4558
4559 for_each_kmem_cache_node(s, node, n) {
4560
4561 if (flags & SO_TOTAL)
4562 x = atomic_long_read(&n->total_objects);
4563 else if (flags & SO_OBJECTS)
4564 x = atomic_long_read(&n->total_objects) -
4565 count_partial(n, count_free);
4566 else
4567 x = atomic_long_read(&n->nr_slabs);
4568 total += x;
4569 nodes[node] += x;
4570 }
4571
4572 } else
4573#endif
4574 if (flags & SO_PARTIAL) {
4575 struct kmem_cache_node *n;
4576
4577 for_each_kmem_cache_node(s, node, n) {
4578 if (flags & SO_TOTAL)
4579 x = count_partial(n, count_total);
4580 else if (flags & SO_OBJECTS)
4581 x = count_partial(n, count_inuse);
4582 else
4583 x = n->nr_partial;
4584 total += x;
4585 nodes[node] += x;
4586 }
4587 }
4588 x = sprintf(buf, "%lu", total);
4589#ifdef CONFIG_NUMA
4590 for (node = 0; node < nr_node_ids; node++)
4591 if (nodes[node])
4592 x += sprintf(buf + x, " N%d=%lu",
4593 node, nodes[node]);
4594#endif
4595 put_online_mems();
4596 kfree(nodes);
4597 return x + sprintf(buf + x, "\n");
4598}
4599
4600#ifdef CONFIG_SLUB_DEBUG
4601static int any_slab_objects(struct kmem_cache *s)
4602{
4603 int node;
4604 struct kmem_cache_node *n;
4605
4606 for_each_kmem_cache_node(s, node, n)
4607 if (atomic_long_read(&n->total_objects))
4608 return 1;
4609
4610 return 0;
4611}
4612#endif
4613
4614#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4615#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4616
4617struct slab_attribute {
4618 struct attribute attr;
4619 ssize_t (*show)(struct kmem_cache *s, char *buf);
4620 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4621};
4622
4623#define SLAB_ATTR_RO(_name) \
4624 static struct slab_attribute _name##_attr = \
4625 __ATTR(_name, 0400, _name##_show, NULL)
4626
4627#define SLAB_ATTR(_name) \
4628 static struct slab_attribute _name##_attr = \
4629 __ATTR(_name, 0600, _name##_show, _name##_store)
4630
4631static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4632{
4633 return sprintf(buf, "%d\n", s->size);
4634}
4635SLAB_ATTR_RO(slab_size);
4636
4637static ssize_t align_show(struct kmem_cache *s, char *buf)
4638{
4639 return sprintf(buf, "%d\n", s->align);
4640}
4641SLAB_ATTR_RO(align);
4642
4643static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4644{
4645 return sprintf(buf, "%d\n", s->object_size);
4646}
4647SLAB_ATTR_RO(object_size);
4648
4649static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4650{
4651 return sprintf(buf, "%d\n", oo_objects(s->oo));
4652}
4653SLAB_ATTR_RO(objs_per_slab);
4654
4655static ssize_t order_store(struct kmem_cache *s,
4656 const char *buf, size_t length)
4657{
4658 unsigned long order;
4659 int err;
4660
4661 err = kstrtoul(buf, 10, &order);
4662 if (err)
4663 return err;
4664
4665 if (order > slub_max_order || order < slub_min_order)
4666 return -EINVAL;
4667
4668 calculate_sizes(s, order);
4669 return length;
4670}
4671
4672static ssize_t order_show(struct kmem_cache *s, char *buf)
4673{
4674 return sprintf(buf, "%d\n", oo_order(s->oo));
4675}
4676SLAB_ATTR(order);
4677
4678static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4679{
4680 return sprintf(buf, "%lu\n", s->min_partial);
4681}
4682
4683static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4684 size_t length)
4685{
4686 unsigned long min;
4687 int err;
4688
4689 err = kstrtoul(buf, 10, &min);
4690 if (err)
4691 return err;
4692
4693 set_min_partial(s, min);
4694 return length;
4695}
4696SLAB_ATTR(min_partial);
4697
4698static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4699{
4700 return sprintf(buf, "%u\n", s->cpu_partial);
4701}
4702
4703static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4704 size_t length)
4705{
4706 unsigned long objects;
4707 int err;
4708
4709 err = kstrtoul(buf, 10, &objects);
4710 if (err)
4711 return err;
4712 if (objects && !kmem_cache_has_cpu_partial(s))
4713 return -EINVAL;
4714
4715 s->cpu_partial = objects;
4716 flush_all(s);
4717 return length;
4718}
4719SLAB_ATTR(cpu_partial);
4720
4721static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4722{
4723 if (!s->ctor)
4724 return 0;
4725 return sprintf(buf, "%pS\n", s->ctor);
4726}
4727SLAB_ATTR_RO(ctor);
4728
4729static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4730{
4731 return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
4732}
4733SLAB_ATTR_RO(aliases);
4734
4735static ssize_t partial_show(struct kmem_cache *s, char *buf)
4736{
4737 return show_slab_objects(s, buf, SO_PARTIAL);
4738}
4739SLAB_ATTR_RO(partial);
4740
4741static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4742{
4743 return show_slab_objects(s, buf, SO_CPU);
4744}
4745SLAB_ATTR_RO(cpu_slabs);
4746
4747static ssize_t objects_show(struct kmem_cache *s, char *buf)
4748{
4749 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4750}
4751SLAB_ATTR_RO(objects);
4752
4753static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4754{
4755 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4756}
4757SLAB_ATTR_RO(objects_partial);
4758
4759static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4760{
4761 int objects = 0;
4762 int pages = 0;
4763 int cpu;
4764 int len;
4765
4766 for_each_online_cpu(cpu) {
4767 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4768
4769 if (page) {
4770 pages += page->pages;
4771 objects += page->pobjects;
4772 }
4773 }
4774
4775 len = sprintf(buf, "%d(%d)", objects, pages);
4776
4777#ifdef CONFIG_SMP
4778 for_each_online_cpu(cpu) {
4779 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4780
4781 if (page && len < PAGE_SIZE - 20)
4782 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4783 page->pobjects, page->pages);
4784 }
4785#endif
4786 return len + sprintf(buf + len, "\n");
4787}
4788SLAB_ATTR_RO(slabs_cpu_partial);
4789
4790static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4791{
4792 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4793}
4794
4795static ssize_t reclaim_account_store(struct kmem_cache *s,
4796 const char *buf, size_t length)
4797{
4798 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4799 if (buf[0] == '1')
4800 s->flags |= SLAB_RECLAIM_ACCOUNT;
4801 return length;
4802}
4803SLAB_ATTR(reclaim_account);
4804
4805static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4806{
4807 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4808}
4809SLAB_ATTR_RO(hwcache_align);
4810
4811#ifdef CONFIG_ZONE_DMA
4812static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4813{
4814 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4815}
4816SLAB_ATTR_RO(cache_dma);
4817#endif
4818
4819static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4820{
4821 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4822}
4823SLAB_ATTR_RO(destroy_by_rcu);
4824
4825static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4826{
4827 return sprintf(buf, "%d\n", s->reserved);
4828}
4829SLAB_ATTR_RO(reserved);
4830
4831#ifdef CONFIG_SLUB_DEBUG
4832static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4833{
4834 return show_slab_objects(s, buf, SO_ALL);
4835}
4836SLAB_ATTR_RO(slabs);
4837
4838static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4839{
4840 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4841}
4842SLAB_ATTR_RO(total_objects);
4843
4844static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4845{
4846 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
4847}
4848
4849static ssize_t sanity_checks_store(struct kmem_cache *s,
4850 const char *buf, size_t length)
4851{
4852 s->flags &= ~SLAB_CONSISTENCY_CHECKS;
4853 if (buf[0] == '1') {
4854 s->flags &= ~__CMPXCHG_DOUBLE;
4855 s->flags |= SLAB_CONSISTENCY_CHECKS;
4856 }
4857 return length;
4858}
4859SLAB_ATTR(sanity_checks);
4860
4861static ssize_t trace_show(struct kmem_cache *s, char *buf)
4862{
4863 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4864}
4865
4866static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4867 size_t length)
4868{
4869 /*
4870 * Tracing a merged cache is going to give confusing results
4871 * as well as cause other issues like converting a mergeable
4872 * cache into an umergeable one.
4873 */
4874 if (s->refcount > 1)
4875 return -EINVAL;
4876
4877 s->flags &= ~SLAB_TRACE;
4878 if (buf[0] == '1') {
4879 s->flags &= ~__CMPXCHG_DOUBLE;
4880 s->flags |= SLAB_TRACE;
4881 }
4882 return length;
4883}
4884SLAB_ATTR(trace);
4885
4886static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4887{
4888 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4889}
4890
4891static ssize_t red_zone_store(struct kmem_cache *s,
4892 const char *buf, size_t length)
4893{
4894 if (any_slab_objects(s))
4895 return -EBUSY;
4896
4897 s->flags &= ~SLAB_RED_ZONE;
4898 if (buf[0] == '1') {
4899 s->flags |= SLAB_RED_ZONE;
4900 }
4901 calculate_sizes(s, -1);
4902 return length;
4903}
4904SLAB_ATTR(red_zone);
4905
4906static ssize_t poison_show(struct kmem_cache *s, char *buf)
4907{
4908 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4909}
4910
4911static ssize_t poison_store(struct kmem_cache *s,
4912 const char *buf, size_t length)
4913{
4914 if (any_slab_objects(s))
4915 return -EBUSY;
4916
4917 s->flags &= ~SLAB_POISON;
4918 if (buf[0] == '1') {
4919 s->flags |= SLAB_POISON;
4920 }
4921 calculate_sizes(s, -1);
4922 return length;
4923}
4924SLAB_ATTR(poison);
4925
4926static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4927{
4928 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4929}
4930
4931static ssize_t store_user_store(struct kmem_cache *s,
4932 const char *buf, size_t length)
4933{
4934 if (any_slab_objects(s))
4935 return -EBUSY;
4936
4937 s->flags &= ~SLAB_STORE_USER;
4938 if (buf[0] == '1') {
4939 s->flags &= ~__CMPXCHG_DOUBLE;
4940 s->flags |= SLAB_STORE_USER;
4941 }
4942 calculate_sizes(s, -1);
4943 return length;
4944}
4945SLAB_ATTR(store_user);
4946
4947static ssize_t validate_show(struct kmem_cache *s, char *buf)
4948{
4949 return 0;
4950}
4951
4952static ssize_t validate_store(struct kmem_cache *s,
4953 const char *buf, size_t length)
4954{
4955 int ret = -EINVAL;
4956
4957 if (buf[0] == '1') {
4958 ret = validate_slab_cache(s);
4959 if (ret >= 0)
4960 ret = length;
4961 }
4962 return ret;
4963}
4964SLAB_ATTR(validate);
4965
4966static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4967{
4968 if (!(s->flags & SLAB_STORE_USER))
4969 return -ENOSYS;
4970 return list_locations(s, buf, TRACK_ALLOC);
4971}
4972SLAB_ATTR_RO(alloc_calls);
4973
4974static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4975{
4976 if (!(s->flags & SLAB_STORE_USER))
4977 return -ENOSYS;
4978 return list_locations(s, buf, TRACK_FREE);
4979}
4980SLAB_ATTR_RO(free_calls);
4981#endif /* CONFIG_SLUB_DEBUG */
4982
4983#ifdef CONFIG_FAILSLAB
4984static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4985{
4986 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4987}
4988
4989static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4990 size_t length)
4991{
4992 if (s->refcount > 1)
4993 return -EINVAL;
4994
4995 s->flags &= ~SLAB_FAILSLAB;
4996 if (buf[0] == '1')
4997 s->flags |= SLAB_FAILSLAB;
4998 return length;
4999}
5000SLAB_ATTR(failslab);
5001#endif
5002
5003static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5004{
5005 return 0;
5006}
5007
5008static ssize_t shrink_store(struct kmem_cache *s,
5009 const char *buf, size_t length)
5010{
5011 if (buf[0] == '1')
5012 kmem_cache_shrink(s);
5013 else
5014 return -EINVAL;
5015 return length;
5016}
5017SLAB_ATTR(shrink);
5018
5019#ifdef CONFIG_NUMA
5020static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5021{
5022 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
5023}
5024
5025static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5026 const char *buf, size_t length)
5027{
5028 unsigned long ratio;
5029 int err;
5030
5031 err = kstrtoul(buf, 10, &ratio);
5032 if (err)
5033 return err;
5034
5035 if (ratio <= 100)
5036 s->remote_node_defrag_ratio = ratio * 10;
5037
5038 return length;
5039}
5040SLAB_ATTR(remote_node_defrag_ratio);
5041#endif
5042
5043#ifdef CONFIG_SLUB_STATS
5044static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5045{
5046 unsigned long sum = 0;
5047 int cpu;
5048 int len;
5049 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5050
5051 if (!data)
5052 return -ENOMEM;
5053
5054 for_each_online_cpu(cpu) {
5055 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5056
5057 data[cpu] = x;
5058 sum += x;
5059 }
5060
5061 len = sprintf(buf, "%lu", sum);
5062
5063#ifdef CONFIG_SMP
5064 for_each_online_cpu(cpu) {
5065 if (data[cpu] && len < PAGE_SIZE - 20)
5066 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5067 }
5068#endif
5069 kfree(data);
5070 return len + sprintf(buf + len, "\n");
5071}
5072
5073static void clear_stat(struct kmem_cache *s, enum stat_item si)
5074{
5075 int cpu;
5076
5077 for_each_online_cpu(cpu)
5078 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5079}
5080
5081#define STAT_ATTR(si, text) \
5082static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5083{ \
5084 return show_stat(s, buf, si); \
5085} \
5086static ssize_t text##_store(struct kmem_cache *s, \
5087 const char *buf, size_t length) \
5088{ \
5089 if (buf[0] != '0') \
5090 return -EINVAL; \
5091 clear_stat(s, si); \
5092 return length; \
5093} \
5094SLAB_ATTR(text); \
5095
5096STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5097STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5098STAT_ATTR(FREE_FASTPATH, free_fastpath);
5099STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5100STAT_ATTR(FREE_FROZEN, free_frozen);
5101STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5102STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5103STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5104STAT_ATTR(ALLOC_SLAB, alloc_slab);
5105STAT_ATTR(ALLOC_REFILL, alloc_refill);
5106STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5107STAT_ATTR(FREE_SLAB, free_slab);
5108STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5109STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5110STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5111STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5112STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5113STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5114STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5115STAT_ATTR(ORDER_FALLBACK, order_fallback);
5116STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5117STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5118STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5119STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5120STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5121STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5122#endif
5123
5124static struct attribute *slab_attrs[] = {
5125 &slab_size_attr.attr,
5126 &object_size_attr.attr,
5127 &objs_per_slab_attr.attr,
5128 &order_attr.attr,
5129 &min_partial_attr.attr,
5130 &cpu_partial_attr.attr,
5131 &objects_attr.attr,
5132 &objects_partial_attr.attr,
5133 &partial_attr.attr,
5134 &cpu_slabs_attr.attr,
5135 &ctor_attr.attr,
5136 &aliases_attr.attr,
5137 &align_attr.attr,
5138 &hwcache_align_attr.attr,
5139 &reclaim_account_attr.attr,
5140 &destroy_by_rcu_attr.attr,
5141 &shrink_attr.attr,
5142 &reserved_attr.attr,
5143 &slabs_cpu_partial_attr.attr,
5144#ifdef CONFIG_SLUB_DEBUG
5145 &total_objects_attr.attr,
5146 &slabs_attr.attr,
5147 &sanity_checks_attr.attr,
5148 &trace_attr.attr,
5149 &red_zone_attr.attr,
5150 &poison_attr.attr,
5151 &store_user_attr.attr,
5152 &validate_attr.attr,
5153 &alloc_calls_attr.attr,
5154 &free_calls_attr.attr,
5155#endif
5156#ifdef CONFIG_ZONE_DMA
5157 &cache_dma_attr.attr,
5158#endif
5159#ifdef CONFIG_NUMA
5160 &remote_node_defrag_ratio_attr.attr,
5161#endif
5162#ifdef CONFIG_SLUB_STATS
5163 &alloc_fastpath_attr.attr,
5164 &alloc_slowpath_attr.attr,
5165 &free_fastpath_attr.attr,
5166 &free_slowpath_attr.attr,
5167 &free_frozen_attr.attr,
5168 &free_add_partial_attr.attr,
5169 &free_remove_partial_attr.attr,
5170 &alloc_from_partial_attr.attr,
5171 &alloc_slab_attr.attr,
5172 &alloc_refill_attr.attr,
5173 &alloc_node_mismatch_attr.attr,
5174 &free_slab_attr.attr,
5175 &cpuslab_flush_attr.attr,
5176 &deactivate_full_attr.attr,
5177 &deactivate_empty_attr.attr,
5178 &deactivate_to_head_attr.attr,
5179 &deactivate_to_tail_attr.attr,
5180 &deactivate_remote_frees_attr.attr,
5181 &deactivate_bypass_attr.attr,
5182 &order_fallback_attr.attr,
5183 &cmpxchg_double_fail_attr.attr,
5184 &cmpxchg_double_cpu_fail_attr.attr,
5185 &cpu_partial_alloc_attr.attr,
5186 &cpu_partial_free_attr.attr,
5187 &cpu_partial_node_attr.attr,
5188 &cpu_partial_drain_attr.attr,
5189#endif
5190#ifdef CONFIG_FAILSLAB
5191 &failslab_attr.attr,
5192#endif
5193
5194 NULL
5195};
5196
5197static struct attribute_group slab_attr_group = {
5198 .attrs = slab_attrs,
5199};
5200
5201static ssize_t slab_attr_show(struct kobject *kobj,
5202 struct attribute *attr,
5203 char *buf)
5204{
5205 struct slab_attribute *attribute;
5206 struct kmem_cache *s;
5207 int err;
5208
5209 attribute = to_slab_attr(attr);
5210 s = to_slab(kobj);
5211
5212 if (!attribute->show)
5213 return -EIO;
5214
5215 err = attribute->show(s, buf);
5216
5217 return err;
5218}
5219
5220static ssize_t slab_attr_store(struct kobject *kobj,
5221 struct attribute *attr,
5222 const char *buf, size_t len)
5223{
5224 struct slab_attribute *attribute;
5225 struct kmem_cache *s;
5226 int err;
5227
5228 attribute = to_slab_attr(attr);
5229 s = to_slab(kobj);
5230
5231 if (!attribute->store)
5232 return -EIO;
5233
5234 err = attribute->store(s, buf, len);
5235#ifdef CONFIG_MEMCG
5236 if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5237 struct kmem_cache *c;
5238
5239 mutex_lock(&slab_mutex);
5240 if (s->max_attr_size < len)
5241 s->max_attr_size = len;
5242
5243 /*
5244 * This is a best effort propagation, so this function's return
5245 * value will be determined by the parent cache only. This is
5246 * basically because not all attributes will have a well
5247 * defined semantics for rollbacks - most of the actions will
5248 * have permanent effects.
5249 *
5250 * Returning the error value of any of the children that fail
5251 * is not 100 % defined, in the sense that users seeing the
5252 * error code won't be able to know anything about the state of
5253 * the cache.
5254 *
5255 * Only returning the error code for the parent cache at least
5256 * has well defined semantics. The cache being written to
5257 * directly either failed or succeeded, in which case we loop
5258 * through the descendants with best-effort propagation.
5259 */
5260 for_each_memcg_cache(c, s)
5261 attribute->store(c, buf, len);
5262 mutex_unlock(&slab_mutex);
5263 }
5264#endif
5265 return err;
5266}
5267
5268static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5269{
5270#ifdef CONFIG_MEMCG
5271 int i;
5272 char *buffer = NULL;
5273 struct kmem_cache *root_cache;
5274
5275 if (is_root_cache(s))
5276 return;
5277
5278 root_cache = s->memcg_params.root_cache;
5279
5280 /*
5281 * This mean this cache had no attribute written. Therefore, no point
5282 * in copying default values around
5283 */
5284 if (!root_cache->max_attr_size)
5285 return;
5286
5287 for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5288 char mbuf[64];
5289 char *buf;
5290 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5291
5292 if (!attr || !attr->store || !attr->show)
5293 continue;
5294
5295 /*
5296 * It is really bad that we have to allocate here, so we will
5297 * do it only as a fallback. If we actually allocate, though,
5298 * we can just use the allocated buffer until the end.
5299 *
5300 * Most of the slub attributes will tend to be very small in
5301 * size, but sysfs allows buffers up to a page, so they can
5302 * theoretically happen.
5303 */
5304 if (buffer)
5305 buf = buffer;
5306 else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5307 buf = mbuf;
5308 else {
5309 buffer = (char *) get_zeroed_page(GFP_KERNEL);
5310 if (WARN_ON(!buffer))
5311 continue;
5312 buf = buffer;
5313 }
5314
5315 attr->show(root_cache, buf);
5316 attr->store(s, buf, strlen(buf));
5317 }
5318
5319 if (buffer)
5320 free_page((unsigned long)buffer);
5321#endif
5322}
5323
5324static void kmem_cache_release(struct kobject *k)
5325{
5326 slab_kmem_cache_release(to_slab(k));
5327}
5328
5329static const struct sysfs_ops slab_sysfs_ops = {
5330 .show = slab_attr_show,
5331 .store = slab_attr_store,
5332};
5333
5334static struct kobj_type slab_ktype = {
5335 .sysfs_ops = &slab_sysfs_ops,
5336 .release = kmem_cache_release,
5337};
5338
5339static int uevent_filter(struct kset *kset, struct kobject *kobj)
5340{
5341 struct kobj_type *ktype = get_ktype(kobj);
5342
5343 if (ktype == &slab_ktype)
5344 return 1;
5345 return 0;
5346}
5347
5348static const struct kset_uevent_ops slab_uevent_ops = {
5349 .filter = uevent_filter,
5350};
5351
5352static struct kset *slab_kset;
5353
5354static inline struct kset *cache_kset(struct kmem_cache *s)
5355{
5356#ifdef CONFIG_MEMCG
5357 if (!is_root_cache(s))
5358 return s->memcg_params.root_cache->memcg_kset;
5359#endif
5360 return slab_kset;
5361}
5362
5363#define ID_STR_LENGTH 64
5364
5365/* Create a unique string id for a slab cache:
5366 *
5367 * Format :[flags-]size
5368 */
5369static char *create_unique_id(struct kmem_cache *s)
5370{
5371 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5372 char *p = name;
5373
5374 BUG_ON(!name);
5375
5376 *p++ = ':';
5377 /*
5378 * First flags affecting slabcache operations. We will only
5379 * get here for aliasable slabs so we do not need to support
5380 * too many flags. The flags here must cover all flags that
5381 * are matched during merging to guarantee that the id is
5382 * unique.
5383 */
5384 if (s->flags & SLAB_CACHE_DMA)
5385 *p++ = 'd';
5386 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5387 *p++ = 'a';
5388 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5389 *p++ = 'F';
5390 if (!(s->flags & SLAB_NOTRACK))
5391 *p++ = 't';
5392 if (s->flags & SLAB_ACCOUNT)
5393 *p++ = 'A';
5394 if (p != name + 1)
5395 *p++ = '-';
5396 p += sprintf(p, "%07d", s->size);
5397
5398 BUG_ON(p > name + ID_STR_LENGTH - 1);
5399 return name;
5400}
5401
5402static int sysfs_slab_add(struct kmem_cache *s)
5403{
5404 int err;
5405 const char *name;
5406 int unmergeable = slab_unmergeable(s);
5407
5408 if (unmergeable) {
5409 /*
5410 * Slabcache can never be merged so we can use the name proper.
5411 * This is typically the case for debug situations. In that
5412 * case we can catch duplicate names easily.
5413 */
5414 sysfs_remove_link(&slab_kset->kobj, s->name);
5415 name = s->name;
5416 } else {
5417 /*
5418 * Create a unique name for the slab as a target
5419 * for the symlinks.
5420 */
5421 name = create_unique_id(s);
5422 }
5423
5424 s->kobj.kset = cache_kset(s);
5425 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5426 if (err)
5427 goto out;
5428
5429 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5430 if (err)
5431 goto out_del_kobj;
5432
5433#ifdef CONFIG_MEMCG
5434 if (is_root_cache(s)) {
5435 s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5436 if (!s->memcg_kset) {
5437 err = -ENOMEM;
5438 goto out_del_kobj;
5439 }
5440 }
5441#endif
5442
5443 kobject_uevent(&s->kobj, KOBJ_ADD);
5444 if (!unmergeable) {
5445 /* Setup first alias */
5446 sysfs_slab_alias(s, s->name);
5447 }
5448out:
5449 if (!unmergeable)
5450 kfree(name);
5451 return err;
5452out_del_kobj:
5453 kobject_del(&s->kobj);
5454 goto out;
5455}
5456
5457void sysfs_slab_remove(struct kmem_cache *s)
5458{
5459 if (slab_state < FULL)
5460 /*
5461 * Sysfs has not been setup yet so no need to remove the
5462 * cache from sysfs.
5463 */
5464 return;
5465
5466#ifdef CONFIG_MEMCG
5467 kset_unregister(s->memcg_kset);
5468#endif
5469 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5470 kobject_del(&s->kobj);
5471 kobject_put(&s->kobj);
5472}
5473
5474/*
5475 * Need to buffer aliases during bootup until sysfs becomes
5476 * available lest we lose that information.
5477 */
5478struct saved_alias {
5479 struct kmem_cache *s;
5480 const char *name;
5481 struct saved_alias *next;
5482};
5483
5484static struct saved_alias *alias_list;
5485
5486static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5487{
5488 struct saved_alias *al;
5489
5490 if (slab_state == FULL) {
5491 /*
5492 * If we have a leftover link then remove it.
5493 */
5494 sysfs_remove_link(&slab_kset->kobj, name);
5495 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5496 }
5497
5498 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5499 if (!al)
5500 return -ENOMEM;
5501
5502 al->s = s;
5503 al->name = name;
5504 al->next = alias_list;
5505 alias_list = al;
5506 return 0;
5507}
5508
5509static int __init slab_sysfs_init(void)
5510{
5511 struct kmem_cache *s;
5512 int err;
5513
5514 mutex_lock(&slab_mutex);
5515
5516 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5517 if (!slab_kset) {
5518 mutex_unlock(&slab_mutex);
5519 pr_err("Cannot register slab subsystem.\n");
5520 return -ENOSYS;
5521 }
5522
5523 slab_state = FULL;
5524
5525 list_for_each_entry(s, &slab_caches, list) {
5526 err = sysfs_slab_add(s);
5527 if (err)
5528 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5529 s->name);
5530 }
5531
5532 while (alias_list) {
5533 struct saved_alias *al = alias_list;
5534
5535 alias_list = alias_list->next;
5536 err = sysfs_slab_alias(al->s, al->name);
5537 if (err)
5538 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5539 al->name);
5540 kfree(al);
5541 }
5542
5543 mutex_unlock(&slab_mutex);
5544 resiliency_test();
5545 return 0;
5546}
5547
5548__initcall(slab_sysfs_init);
5549#endif /* CONFIG_SYSFS */
5550
5551/*
5552 * The /proc/slabinfo ABI
5553 */
5554#ifdef CONFIG_SLABINFO
5555void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5556{
5557 unsigned long nr_slabs = 0;
5558 unsigned long nr_objs = 0;
5559 unsigned long nr_free = 0;
5560 int node;
5561 struct kmem_cache_node *n;
5562
5563 for_each_kmem_cache_node(s, node, n) {
5564 nr_slabs += node_nr_slabs(n);
5565 nr_objs += node_nr_objs(n);
5566 nr_free += count_partial(n, count_free);
5567 }
5568
5569 sinfo->active_objs = nr_objs - nr_free;
5570 sinfo->num_objs = nr_objs;
5571 sinfo->active_slabs = nr_slabs;
5572 sinfo->num_slabs = nr_slabs;
5573 sinfo->objects_per_slab = oo_objects(s->oo);
5574 sinfo->cache_order = oo_order(s->oo);
5575}
5576
5577void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5578{
5579}
5580
5581ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5582 size_t count, loff_t *ppos)
5583{
5584 return -EIO;
5585}
5586#endif /* CONFIG_SLABINFO */
1/*
2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
4 *
5 * The allocator synchronizes using per slab locks or atomic operatios
6 * and only uses a centralized lock to manage a pool of partial slabs.
7 *
8 * (C) 2007 SGI, Christoph Lameter
9 * (C) 2011 Linux Foundation, Christoph Lameter
10 */
11
12#include <linux/mm.h>
13#include <linux/swap.h> /* struct reclaim_state */
14#include <linux/module.h>
15#include <linux/bit_spinlock.h>
16#include <linux/interrupt.h>
17#include <linux/bitops.h>
18#include <linux/slab.h>
19#include <linux/proc_fs.h>
20#include <linux/seq_file.h>
21#include <linux/kmemcheck.h>
22#include <linux/cpu.h>
23#include <linux/cpuset.h>
24#include <linux/mempolicy.h>
25#include <linux/ctype.h>
26#include <linux/debugobjects.h>
27#include <linux/kallsyms.h>
28#include <linux/memory.h>
29#include <linux/math64.h>
30#include <linux/fault-inject.h>
31#include <linux/stacktrace.h>
32#include <linux/prefetch.h>
33
34#include <trace/events/kmem.h>
35
36/*
37 * Lock order:
38 * 1. slub_lock (Global Semaphore)
39 * 2. node->list_lock
40 * 3. slab_lock(page) (Only on some arches and for debugging)
41 *
42 * slub_lock
43 *
44 * The role of the slub_lock is to protect the list of all the slabs
45 * and to synchronize major metadata changes to slab cache structures.
46 *
47 * The slab_lock is only used for debugging and on arches that do not
48 * have the ability to do a cmpxchg_double. It only protects the second
49 * double word in the page struct. Meaning
50 * A. page->freelist -> List of object free in a page
51 * B. page->counters -> Counters of objects
52 * C. page->frozen -> frozen state
53 *
54 * If a slab is frozen then it is exempt from list management. It is not
55 * on any list. The processor that froze the slab is the one who can
56 * perform list operations on the page. Other processors may put objects
57 * onto the freelist but the processor that froze the slab is the only
58 * one that can retrieve the objects from the page's freelist.
59 *
60 * The list_lock protects the partial and full list on each node and
61 * the partial slab counter. If taken then no new slabs may be added or
62 * removed from the lists nor make the number of partial slabs be modified.
63 * (Note that the total number of slabs is an atomic value that may be
64 * modified without taking the list lock).
65 *
66 * The list_lock is a centralized lock and thus we avoid taking it as
67 * much as possible. As long as SLUB does not have to handle partial
68 * slabs, operations can continue without any centralized lock. F.e.
69 * allocating a long series of objects that fill up slabs does not require
70 * the list lock.
71 * Interrupts are disabled during allocation and deallocation in order to
72 * make the slab allocator safe to use in the context of an irq. In addition
73 * interrupts are disabled to ensure that the processor does not change
74 * while handling per_cpu slabs, due to kernel preemption.
75 *
76 * SLUB assigns one slab for allocation to each processor.
77 * Allocations only occur from these slabs called cpu slabs.
78 *
79 * Slabs with free elements are kept on a partial list and during regular
80 * operations no list for full slabs is used. If an object in a full slab is
81 * freed then the slab will show up again on the partial lists.
82 * We track full slabs for debugging purposes though because otherwise we
83 * cannot scan all objects.
84 *
85 * Slabs are freed when they become empty. Teardown and setup is
86 * minimal so we rely on the page allocators per cpu caches for
87 * fast frees and allocs.
88 *
89 * Overloading of page flags that are otherwise used for LRU management.
90 *
91 * PageActive The slab is frozen and exempt from list processing.
92 * This means that the slab is dedicated to a purpose
93 * such as satisfying allocations for a specific
94 * processor. Objects may be freed in the slab while
95 * it is frozen but slab_free will then skip the usual
96 * list operations. It is up to the processor holding
97 * the slab to integrate the slab into the slab lists
98 * when the slab is no longer needed.
99 *
100 * One use of this flag is to mark slabs that are
101 * used for allocations. Then such a slab becomes a cpu
102 * slab. The cpu slab may be equipped with an additional
103 * freelist that allows lockless access to
104 * free objects in addition to the regular freelist
105 * that requires the slab lock.
106 *
107 * PageError Slab requires special handling due to debug
108 * options set. This moves slab handling out of
109 * the fast path and disables lockless freelists.
110 */
111
112#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
113 SLAB_TRACE | SLAB_DEBUG_FREE)
114
115static inline int kmem_cache_debug(struct kmem_cache *s)
116{
117#ifdef CONFIG_SLUB_DEBUG
118 return unlikely(s->flags & SLAB_DEBUG_FLAGS);
119#else
120 return 0;
121#endif
122}
123
124/*
125 * Issues still to be resolved:
126 *
127 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
128 *
129 * - Variable sizing of the per node arrays
130 */
131
132/* Enable to test recovery from slab corruption on boot */
133#undef SLUB_RESILIENCY_TEST
134
135/* Enable to log cmpxchg failures */
136#undef SLUB_DEBUG_CMPXCHG
137
138/*
139 * Mininum number of partial slabs. These will be left on the partial
140 * lists even if they are empty. kmem_cache_shrink may reclaim them.
141 */
142#define MIN_PARTIAL 5
143
144/*
145 * Maximum number of desirable partial slabs.
146 * The existence of more partial slabs makes kmem_cache_shrink
147 * sort the partial list by the number of objects in the.
148 */
149#define MAX_PARTIAL 10
150
151#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
152 SLAB_POISON | SLAB_STORE_USER)
153
154/*
155 * Debugging flags that require metadata to be stored in the slab. These get
156 * disabled when slub_debug=O is used and a cache's min order increases with
157 * metadata.
158 */
159#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
160
161/*
162 * Set of flags that will prevent slab merging
163 */
164#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
165 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
166 SLAB_FAILSLAB)
167
168#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
169 SLAB_CACHE_DMA | SLAB_NOTRACK)
170
171#define OO_SHIFT 16
172#define OO_MASK ((1 << OO_SHIFT) - 1)
173#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
174
175/* Internal SLUB flags */
176#define __OBJECT_POISON 0x80000000UL /* Poison object */
177#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
178
179static int kmem_size = sizeof(struct kmem_cache);
180
181#ifdef CONFIG_SMP
182static struct notifier_block slab_notifier;
183#endif
184
185static enum {
186 DOWN, /* No slab functionality available */
187 PARTIAL, /* Kmem_cache_node works */
188 UP, /* Everything works but does not show up in sysfs */
189 SYSFS /* Sysfs up */
190} slab_state = DOWN;
191
192/* A list of all slab caches on the system */
193static DECLARE_RWSEM(slub_lock);
194static LIST_HEAD(slab_caches);
195
196/*
197 * Tracking user of a slab.
198 */
199#define TRACK_ADDRS_COUNT 16
200struct track {
201 unsigned long addr; /* Called from address */
202#ifdef CONFIG_STACKTRACE
203 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
204#endif
205 int cpu; /* Was running on cpu */
206 int pid; /* Pid context */
207 unsigned long when; /* When did the operation occur */
208};
209
210enum track_item { TRACK_ALLOC, TRACK_FREE };
211
212#ifdef CONFIG_SYSFS
213static int sysfs_slab_add(struct kmem_cache *);
214static int sysfs_slab_alias(struct kmem_cache *, const char *);
215static void sysfs_slab_remove(struct kmem_cache *);
216
217#else
218static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
219static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
220 { return 0; }
221static inline void sysfs_slab_remove(struct kmem_cache *s)
222{
223 kfree(s->name);
224 kfree(s);
225}
226
227#endif
228
229static inline void stat(const struct kmem_cache *s, enum stat_item si)
230{
231#ifdef CONFIG_SLUB_STATS
232 __this_cpu_inc(s->cpu_slab->stat[si]);
233#endif
234}
235
236/********************************************************************
237 * Core slab cache functions
238 *******************************************************************/
239
240int slab_is_available(void)
241{
242 return slab_state >= UP;
243}
244
245static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
246{
247 return s->node[node];
248}
249
250/* Verify that a pointer has an address that is valid within a slab page */
251static inline int check_valid_pointer(struct kmem_cache *s,
252 struct page *page, const void *object)
253{
254 void *base;
255
256 if (!object)
257 return 1;
258
259 base = page_address(page);
260 if (object < base || object >= base + page->objects * s->size ||
261 (object - base) % s->size) {
262 return 0;
263 }
264
265 return 1;
266}
267
268static inline void *get_freepointer(struct kmem_cache *s, void *object)
269{
270 return *(void **)(object + s->offset);
271}
272
273static void prefetch_freepointer(const struct kmem_cache *s, void *object)
274{
275 prefetch(object + s->offset);
276}
277
278static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
279{
280 void *p;
281
282#ifdef CONFIG_DEBUG_PAGEALLOC
283 probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
284#else
285 p = get_freepointer(s, object);
286#endif
287 return p;
288}
289
290static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
291{
292 *(void **)(object + s->offset) = fp;
293}
294
295/* Loop over all objects in a slab */
296#define for_each_object(__p, __s, __addr, __objects) \
297 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
298 __p += (__s)->size)
299
300/* Determine object index from a given position */
301static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
302{
303 return (p - addr) / s->size;
304}
305
306static inline size_t slab_ksize(const struct kmem_cache *s)
307{
308#ifdef CONFIG_SLUB_DEBUG
309 /*
310 * Debugging requires use of the padding between object
311 * and whatever may come after it.
312 */
313 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
314 return s->objsize;
315
316#endif
317 /*
318 * If we have the need to store the freelist pointer
319 * back there or track user information then we can
320 * only use the space before that information.
321 */
322 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
323 return s->inuse;
324 /*
325 * Else we can use all the padding etc for the allocation
326 */
327 return s->size;
328}
329
330static inline int order_objects(int order, unsigned long size, int reserved)
331{
332 return ((PAGE_SIZE << order) - reserved) / size;
333}
334
335static inline struct kmem_cache_order_objects oo_make(int order,
336 unsigned long size, int reserved)
337{
338 struct kmem_cache_order_objects x = {
339 (order << OO_SHIFT) + order_objects(order, size, reserved)
340 };
341
342 return x;
343}
344
345static inline int oo_order(struct kmem_cache_order_objects x)
346{
347 return x.x >> OO_SHIFT;
348}
349
350static inline int oo_objects(struct kmem_cache_order_objects x)
351{
352 return x.x & OO_MASK;
353}
354
355/*
356 * Per slab locking using the pagelock
357 */
358static __always_inline void slab_lock(struct page *page)
359{
360 bit_spin_lock(PG_locked, &page->flags);
361}
362
363static __always_inline void slab_unlock(struct page *page)
364{
365 __bit_spin_unlock(PG_locked, &page->flags);
366}
367
368/* Interrupts must be disabled (for the fallback code to work right) */
369static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
370 void *freelist_old, unsigned long counters_old,
371 void *freelist_new, unsigned long counters_new,
372 const char *n)
373{
374 VM_BUG_ON(!irqs_disabled());
375#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
376 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
377 if (s->flags & __CMPXCHG_DOUBLE) {
378 if (cmpxchg_double(&page->freelist, &page->counters,
379 freelist_old, counters_old,
380 freelist_new, counters_new))
381 return 1;
382 } else
383#endif
384 {
385 slab_lock(page);
386 if (page->freelist == freelist_old && page->counters == counters_old) {
387 page->freelist = freelist_new;
388 page->counters = counters_new;
389 slab_unlock(page);
390 return 1;
391 }
392 slab_unlock(page);
393 }
394
395 cpu_relax();
396 stat(s, CMPXCHG_DOUBLE_FAIL);
397
398#ifdef SLUB_DEBUG_CMPXCHG
399 printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
400#endif
401
402 return 0;
403}
404
405static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
406 void *freelist_old, unsigned long counters_old,
407 void *freelist_new, unsigned long counters_new,
408 const char *n)
409{
410#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
411 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
412 if (s->flags & __CMPXCHG_DOUBLE) {
413 if (cmpxchg_double(&page->freelist, &page->counters,
414 freelist_old, counters_old,
415 freelist_new, counters_new))
416 return 1;
417 } else
418#endif
419 {
420 unsigned long flags;
421
422 local_irq_save(flags);
423 slab_lock(page);
424 if (page->freelist == freelist_old && page->counters == counters_old) {
425 page->freelist = freelist_new;
426 page->counters = counters_new;
427 slab_unlock(page);
428 local_irq_restore(flags);
429 return 1;
430 }
431 slab_unlock(page);
432 local_irq_restore(flags);
433 }
434
435 cpu_relax();
436 stat(s, CMPXCHG_DOUBLE_FAIL);
437
438#ifdef SLUB_DEBUG_CMPXCHG
439 printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
440#endif
441
442 return 0;
443}
444
445#ifdef CONFIG_SLUB_DEBUG
446/*
447 * Determine a map of object in use on a page.
448 *
449 * Node listlock must be held to guarantee that the page does
450 * not vanish from under us.
451 */
452static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
453{
454 void *p;
455 void *addr = page_address(page);
456
457 for (p = page->freelist; p; p = get_freepointer(s, p))
458 set_bit(slab_index(p, s, addr), map);
459}
460
461/*
462 * Debug settings:
463 */
464#ifdef CONFIG_SLUB_DEBUG_ON
465static int slub_debug = DEBUG_DEFAULT_FLAGS;
466#else
467static int slub_debug;
468#endif
469
470static char *slub_debug_slabs;
471static int disable_higher_order_debug;
472
473/*
474 * Object debugging
475 */
476static void print_section(char *text, u8 *addr, unsigned int length)
477{
478 print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
479 length, 1);
480}
481
482static struct track *get_track(struct kmem_cache *s, void *object,
483 enum track_item alloc)
484{
485 struct track *p;
486
487 if (s->offset)
488 p = object + s->offset + sizeof(void *);
489 else
490 p = object + s->inuse;
491
492 return p + alloc;
493}
494
495static void set_track(struct kmem_cache *s, void *object,
496 enum track_item alloc, unsigned long addr)
497{
498 struct track *p = get_track(s, object, alloc);
499
500 if (addr) {
501#ifdef CONFIG_STACKTRACE
502 struct stack_trace trace;
503 int i;
504
505 trace.nr_entries = 0;
506 trace.max_entries = TRACK_ADDRS_COUNT;
507 trace.entries = p->addrs;
508 trace.skip = 3;
509 save_stack_trace(&trace);
510
511 /* See rant in lockdep.c */
512 if (trace.nr_entries != 0 &&
513 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
514 trace.nr_entries--;
515
516 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
517 p->addrs[i] = 0;
518#endif
519 p->addr = addr;
520 p->cpu = smp_processor_id();
521 p->pid = current->pid;
522 p->when = jiffies;
523 } else
524 memset(p, 0, sizeof(struct track));
525}
526
527static void init_tracking(struct kmem_cache *s, void *object)
528{
529 if (!(s->flags & SLAB_STORE_USER))
530 return;
531
532 set_track(s, object, TRACK_FREE, 0UL);
533 set_track(s, object, TRACK_ALLOC, 0UL);
534}
535
536static void print_track(const char *s, struct track *t)
537{
538 if (!t->addr)
539 return;
540
541 printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
542 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
543#ifdef CONFIG_STACKTRACE
544 {
545 int i;
546 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
547 if (t->addrs[i])
548 printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
549 else
550 break;
551 }
552#endif
553}
554
555static void print_tracking(struct kmem_cache *s, void *object)
556{
557 if (!(s->flags & SLAB_STORE_USER))
558 return;
559
560 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
561 print_track("Freed", get_track(s, object, TRACK_FREE));
562}
563
564static void print_page_info(struct page *page)
565{
566 printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
567 page, page->objects, page->inuse, page->freelist, page->flags);
568
569}
570
571static void slab_bug(struct kmem_cache *s, char *fmt, ...)
572{
573 va_list args;
574 char buf[100];
575
576 va_start(args, fmt);
577 vsnprintf(buf, sizeof(buf), fmt, args);
578 va_end(args);
579 printk(KERN_ERR "========================================"
580 "=====================================\n");
581 printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
582 printk(KERN_ERR "----------------------------------------"
583 "-------------------------------------\n\n");
584}
585
586static void slab_fix(struct kmem_cache *s, char *fmt, ...)
587{
588 va_list args;
589 char buf[100];
590
591 va_start(args, fmt);
592 vsnprintf(buf, sizeof(buf), fmt, args);
593 va_end(args);
594 printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
595}
596
597static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
598{
599 unsigned int off; /* Offset of last byte */
600 u8 *addr = page_address(page);
601
602 print_tracking(s, p);
603
604 print_page_info(page);
605
606 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
607 p, p - addr, get_freepointer(s, p));
608
609 if (p > addr + 16)
610 print_section("Bytes b4 ", p - 16, 16);
611
612 print_section("Object ", p, min_t(unsigned long, s->objsize,
613 PAGE_SIZE));
614 if (s->flags & SLAB_RED_ZONE)
615 print_section("Redzone ", p + s->objsize,
616 s->inuse - s->objsize);
617
618 if (s->offset)
619 off = s->offset + sizeof(void *);
620 else
621 off = s->inuse;
622
623 if (s->flags & SLAB_STORE_USER)
624 off += 2 * sizeof(struct track);
625
626 if (off != s->size)
627 /* Beginning of the filler is the free pointer */
628 print_section("Padding ", p + off, s->size - off);
629
630 dump_stack();
631}
632
633static void object_err(struct kmem_cache *s, struct page *page,
634 u8 *object, char *reason)
635{
636 slab_bug(s, "%s", reason);
637 print_trailer(s, page, object);
638}
639
640static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
641{
642 va_list args;
643 char buf[100];
644
645 va_start(args, fmt);
646 vsnprintf(buf, sizeof(buf), fmt, args);
647 va_end(args);
648 slab_bug(s, "%s", buf);
649 print_page_info(page);
650 dump_stack();
651}
652
653static void init_object(struct kmem_cache *s, void *object, u8 val)
654{
655 u8 *p = object;
656
657 if (s->flags & __OBJECT_POISON) {
658 memset(p, POISON_FREE, s->objsize - 1);
659 p[s->objsize - 1] = POISON_END;
660 }
661
662 if (s->flags & SLAB_RED_ZONE)
663 memset(p + s->objsize, val, s->inuse - s->objsize);
664}
665
666static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
667 void *from, void *to)
668{
669 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
670 memset(from, data, to - from);
671}
672
673static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
674 u8 *object, char *what,
675 u8 *start, unsigned int value, unsigned int bytes)
676{
677 u8 *fault;
678 u8 *end;
679
680 fault = memchr_inv(start, value, bytes);
681 if (!fault)
682 return 1;
683
684 end = start + bytes;
685 while (end > fault && end[-1] == value)
686 end--;
687
688 slab_bug(s, "%s overwritten", what);
689 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
690 fault, end - 1, fault[0], value);
691 print_trailer(s, page, object);
692
693 restore_bytes(s, what, value, fault, end);
694 return 0;
695}
696
697/*
698 * Object layout:
699 *
700 * object address
701 * Bytes of the object to be managed.
702 * If the freepointer may overlay the object then the free
703 * pointer is the first word of the object.
704 *
705 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
706 * 0xa5 (POISON_END)
707 *
708 * object + s->objsize
709 * Padding to reach word boundary. This is also used for Redzoning.
710 * Padding is extended by another word if Redzoning is enabled and
711 * objsize == inuse.
712 *
713 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
714 * 0xcc (RED_ACTIVE) for objects in use.
715 *
716 * object + s->inuse
717 * Meta data starts here.
718 *
719 * A. Free pointer (if we cannot overwrite object on free)
720 * B. Tracking data for SLAB_STORE_USER
721 * C. Padding to reach required alignment boundary or at mininum
722 * one word if debugging is on to be able to detect writes
723 * before the word boundary.
724 *
725 * Padding is done using 0x5a (POISON_INUSE)
726 *
727 * object + s->size
728 * Nothing is used beyond s->size.
729 *
730 * If slabcaches are merged then the objsize and inuse boundaries are mostly
731 * ignored. And therefore no slab options that rely on these boundaries
732 * may be used with merged slabcaches.
733 */
734
735static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
736{
737 unsigned long off = s->inuse; /* The end of info */
738
739 if (s->offset)
740 /* Freepointer is placed after the object. */
741 off += sizeof(void *);
742
743 if (s->flags & SLAB_STORE_USER)
744 /* We also have user information there */
745 off += 2 * sizeof(struct track);
746
747 if (s->size == off)
748 return 1;
749
750 return check_bytes_and_report(s, page, p, "Object padding",
751 p + off, POISON_INUSE, s->size - off);
752}
753
754/* Check the pad bytes at the end of a slab page */
755static int slab_pad_check(struct kmem_cache *s, struct page *page)
756{
757 u8 *start;
758 u8 *fault;
759 u8 *end;
760 int length;
761 int remainder;
762
763 if (!(s->flags & SLAB_POISON))
764 return 1;
765
766 start = page_address(page);
767 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
768 end = start + length;
769 remainder = length % s->size;
770 if (!remainder)
771 return 1;
772
773 fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
774 if (!fault)
775 return 1;
776 while (end > fault && end[-1] == POISON_INUSE)
777 end--;
778
779 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
780 print_section("Padding ", end - remainder, remainder);
781
782 restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
783 return 0;
784}
785
786static int check_object(struct kmem_cache *s, struct page *page,
787 void *object, u8 val)
788{
789 u8 *p = object;
790 u8 *endobject = object + s->objsize;
791
792 if (s->flags & SLAB_RED_ZONE) {
793 if (!check_bytes_and_report(s, page, object, "Redzone",
794 endobject, val, s->inuse - s->objsize))
795 return 0;
796 } else {
797 if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
798 check_bytes_and_report(s, page, p, "Alignment padding",
799 endobject, POISON_INUSE, s->inuse - s->objsize);
800 }
801 }
802
803 if (s->flags & SLAB_POISON) {
804 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
805 (!check_bytes_and_report(s, page, p, "Poison", p,
806 POISON_FREE, s->objsize - 1) ||
807 !check_bytes_and_report(s, page, p, "Poison",
808 p + s->objsize - 1, POISON_END, 1)))
809 return 0;
810 /*
811 * check_pad_bytes cleans up on its own.
812 */
813 check_pad_bytes(s, page, p);
814 }
815
816 if (!s->offset && val == SLUB_RED_ACTIVE)
817 /*
818 * Object and freepointer overlap. Cannot check
819 * freepointer while object is allocated.
820 */
821 return 1;
822
823 /* Check free pointer validity */
824 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
825 object_err(s, page, p, "Freepointer corrupt");
826 /*
827 * No choice but to zap it and thus lose the remainder
828 * of the free objects in this slab. May cause
829 * another error because the object count is now wrong.
830 */
831 set_freepointer(s, p, NULL);
832 return 0;
833 }
834 return 1;
835}
836
837static int check_slab(struct kmem_cache *s, struct page *page)
838{
839 int maxobj;
840
841 VM_BUG_ON(!irqs_disabled());
842
843 if (!PageSlab(page)) {
844 slab_err(s, page, "Not a valid slab page");
845 return 0;
846 }
847
848 maxobj = order_objects(compound_order(page), s->size, s->reserved);
849 if (page->objects > maxobj) {
850 slab_err(s, page, "objects %u > max %u",
851 s->name, page->objects, maxobj);
852 return 0;
853 }
854 if (page->inuse > page->objects) {
855 slab_err(s, page, "inuse %u > max %u",
856 s->name, page->inuse, page->objects);
857 return 0;
858 }
859 /* Slab_pad_check fixes things up after itself */
860 slab_pad_check(s, page);
861 return 1;
862}
863
864/*
865 * Determine if a certain object on a page is on the freelist. Must hold the
866 * slab lock to guarantee that the chains are in a consistent state.
867 */
868static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
869{
870 int nr = 0;
871 void *fp;
872 void *object = NULL;
873 unsigned long max_objects;
874
875 fp = page->freelist;
876 while (fp && nr <= page->objects) {
877 if (fp == search)
878 return 1;
879 if (!check_valid_pointer(s, page, fp)) {
880 if (object) {
881 object_err(s, page, object,
882 "Freechain corrupt");
883 set_freepointer(s, object, NULL);
884 break;
885 } else {
886 slab_err(s, page, "Freepointer corrupt");
887 page->freelist = NULL;
888 page->inuse = page->objects;
889 slab_fix(s, "Freelist cleared");
890 return 0;
891 }
892 break;
893 }
894 object = fp;
895 fp = get_freepointer(s, object);
896 nr++;
897 }
898
899 max_objects = order_objects(compound_order(page), s->size, s->reserved);
900 if (max_objects > MAX_OBJS_PER_PAGE)
901 max_objects = MAX_OBJS_PER_PAGE;
902
903 if (page->objects != max_objects) {
904 slab_err(s, page, "Wrong number of objects. Found %d but "
905 "should be %d", page->objects, max_objects);
906 page->objects = max_objects;
907 slab_fix(s, "Number of objects adjusted.");
908 }
909 if (page->inuse != page->objects - nr) {
910 slab_err(s, page, "Wrong object count. Counter is %d but "
911 "counted were %d", page->inuse, page->objects - nr);
912 page->inuse = page->objects - nr;
913 slab_fix(s, "Object count adjusted.");
914 }
915 return search == NULL;
916}
917
918static void trace(struct kmem_cache *s, struct page *page, void *object,
919 int alloc)
920{
921 if (s->flags & SLAB_TRACE) {
922 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
923 s->name,
924 alloc ? "alloc" : "free",
925 object, page->inuse,
926 page->freelist);
927
928 if (!alloc)
929 print_section("Object ", (void *)object, s->objsize);
930
931 dump_stack();
932 }
933}
934
935/*
936 * Hooks for other subsystems that check memory allocations. In a typical
937 * production configuration these hooks all should produce no code at all.
938 */
939static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
940{
941 flags &= gfp_allowed_mask;
942 lockdep_trace_alloc(flags);
943 might_sleep_if(flags & __GFP_WAIT);
944
945 return should_failslab(s->objsize, flags, s->flags);
946}
947
948static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
949{
950 flags &= gfp_allowed_mask;
951 kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
952 kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
953}
954
955static inline void slab_free_hook(struct kmem_cache *s, void *x)
956{
957 kmemleak_free_recursive(x, s->flags);
958
959 /*
960 * Trouble is that we may no longer disable interupts in the fast path
961 * So in order to make the debug calls that expect irqs to be
962 * disabled we need to disable interrupts temporarily.
963 */
964#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
965 {
966 unsigned long flags;
967
968 local_irq_save(flags);
969 kmemcheck_slab_free(s, x, s->objsize);
970 debug_check_no_locks_freed(x, s->objsize);
971 local_irq_restore(flags);
972 }
973#endif
974 if (!(s->flags & SLAB_DEBUG_OBJECTS))
975 debug_check_no_obj_freed(x, s->objsize);
976}
977
978/*
979 * Tracking of fully allocated slabs for debugging purposes.
980 *
981 * list_lock must be held.
982 */
983static void add_full(struct kmem_cache *s,
984 struct kmem_cache_node *n, struct page *page)
985{
986 if (!(s->flags & SLAB_STORE_USER))
987 return;
988
989 list_add(&page->lru, &n->full);
990}
991
992/*
993 * list_lock must be held.
994 */
995static void remove_full(struct kmem_cache *s, struct page *page)
996{
997 if (!(s->flags & SLAB_STORE_USER))
998 return;
999
1000 list_del(&page->lru);
1001}
1002
1003/* Tracking of the number of slabs for debugging purposes */
1004static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1005{
1006 struct kmem_cache_node *n = get_node(s, node);
1007
1008 return atomic_long_read(&n->nr_slabs);
1009}
1010
1011static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1012{
1013 return atomic_long_read(&n->nr_slabs);
1014}
1015
1016static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1017{
1018 struct kmem_cache_node *n = get_node(s, node);
1019
1020 /*
1021 * May be called early in order to allocate a slab for the
1022 * kmem_cache_node structure. Solve the chicken-egg
1023 * dilemma by deferring the increment of the count during
1024 * bootstrap (see early_kmem_cache_node_alloc).
1025 */
1026 if (n) {
1027 atomic_long_inc(&n->nr_slabs);
1028 atomic_long_add(objects, &n->total_objects);
1029 }
1030}
1031static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1032{
1033 struct kmem_cache_node *n = get_node(s, node);
1034
1035 atomic_long_dec(&n->nr_slabs);
1036 atomic_long_sub(objects, &n->total_objects);
1037}
1038
1039/* Object debug checks for alloc/free paths */
1040static void setup_object_debug(struct kmem_cache *s, struct page *page,
1041 void *object)
1042{
1043 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1044 return;
1045
1046 init_object(s, object, SLUB_RED_INACTIVE);
1047 init_tracking(s, object);
1048}
1049
1050static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1051 void *object, unsigned long addr)
1052{
1053 if (!check_slab(s, page))
1054 goto bad;
1055
1056 if (!check_valid_pointer(s, page, object)) {
1057 object_err(s, page, object, "Freelist Pointer check fails");
1058 goto bad;
1059 }
1060
1061 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1062 goto bad;
1063
1064 /* Success perform special debug activities for allocs */
1065 if (s->flags & SLAB_STORE_USER)
1066 set_track(s, object, TRACK_ALLOC, addr);
1067 trace(s, page, object, 1);
1068 init_object(s, object, SLUB_RED_ACTIVE);
1069 return 1;
1070
1071bad:
1072 if (PageSlab(page)) {
1073 /*
1074 * If this is a slab page then lets do the best we can
1075 * to avoid issues in the future. Marking all objects
1076 * as used avoids touching the remaining objects.
1077 */
1078 slab_fix(s, "Marking all objects used");
1079 page->inuse = page->objects;
1080 page->freelist = NULL;
1081 }
1082 return 0;
1083}
1084
1085static noinline int free_debug_processing(struct kmem_cache *s,
1086 struct page *page, void *object, unsigned long addr)
1087{
1088 unsigned long flags;
1089 int rc = 0;
1090
1091 local_irq_save(flags);
1092 slab_lock(page);
1093
1094 if (!check_slab(s, page))
1095 goto fail;
1096
1097 if (!check_valid_pointer(s, page, object)) {
1098 slab_err(s, page, "Invalid object pointer 0x%p", object);
1099 goto fail;
1100 }
1101
1102 if (on_freelist(s, page, object)) {
1103 object_err(s, page, object, "Object already free");
1104 goto fail;
1105 }
1106
1107 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1108 goto out;
1109
1110 if (unlikely(s != page->slab)) {
1111 if (!PageSlab(page)) {
1112 slab_err(s, page, "Attempt to free object(0x%p) "
1113 "outside of slab", object);
1114 } else if (!page->slab) {
1115 printk(KERN_ERR
1116 "SLUB <none>: no slab for object 0x%p.\n",
1117 object);
1118 dump_stack();
1119 } else
1120 object_err(s, page, object,
1121 "page slab pointer corrupt.");
1122 goto fail;
1123 }
1124
1125 if (s->flags & SLAB_STORE_USER)
1126 set_track(s, object, TRACK_FREE, addr);
1127 trace(s, page, object, 0);
1128 init_object(s, object, SLUB_RED_INACTIVE);
1129 rc = 1;
1130out:
1131 slab_unlock(page);
1132 local_irq_restore(flags);
1133 return rc;
1134
1135fail:
1136 slab_fix(s, "Object at 0x%p not freed", object);
1137 goto out;
1138}
1139
1140static int __init setup_slub_debug(char *str)
1141{
1142 slub_debug = DEBUG_DEFAULT_FLAGS;
1143 if (*str++ != '=' || !*str)
1144 /*
1145 * No options specified. Switch on full debugging.
1146 */
1147 goto out;
1148
1149 if (*str == ',')
1150 /*
1151 * No options but restriction on slabs. This means full
1152 * debugging for slabs matching a pattern.
1153 */
1154 goto check_slabs;
1155
1156 if (tolower(*str) == 'o') {
1157 /*
1158 * Avoid enabling debugging on caches if its minimum order
1159 * would increase as a result.
1160 */
1161 disable_higher_order_debug = 1;
1162 goto out;
1163 }
1164
1165 slub_debug = 0;
1166 if (*str == '-')
1167 /*
1168 * Switch off all debugging measures.
1169 */
1170 goto out;
1171
1172 /*
1173 * Determine which debug features should be switched on
1174 */
1175 for (; *str && *str != ','; str++) {
1176 switch (tolower(*str)) {
1177 case 'f':
1178 slub_debug |= SLAB_DEBUG_FREE;
1179 break;
1180 case 'z':
1181 slub_debug |= SLAB_RED_ZONE;
1182 break;
1183 case 'p':
1184 slub_debug |= SLAB_POISON;
1185 break;
1186 case 'u':
1187 slub_debug |= SLAB_STORE_USER;
1188 break;
1189 case 't':
1190 slub_debug |= SLAB_TRACE;
1191 break;
1192 case 'a':
1193 slub_debug |= SLAB_FAILSLAB;
1194 break;
1195 default:
1196 printk(KERN_ERR "slub_debug option '%c' "
1197 "unknown. skipped\n", *str);
1198 }
1199 }
1200
1201check_slabs:
1202 if (*str == ',')
1203 slub_debug_slabs = str + 1;
1204out:
1205 return 1;
1206}
1207
1208__setup("slub_debug", setup_slub_debug);
1209
1210static unsigned long kmem_cache_flags(unsigned long objsize,
1211 unsigned long flags, const char *name,
1212 void (*ctor)(void *))
1213{
1214 /*
1215 * Enable debugging if selected on the kernel commandline.
1216 */
1217 if (slub_debug && (!slub_debug_slabs ||
1218 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1219 flags |= slub_debug;
1220
1221 return flags;
1222}
1223#else
1224static inline void setup_object_debug(struct kmem_cache *s,
1225 struct page *page, void *object) {}
1226
1227static inline int alloc_debug_processing(struct kmem_cache *s,
1228 struct page *page, void *object, unsigned long addr) { return 0; }
1229
1230static inline int free_debug_processing(struct kmem_cache *s,
1231 struct page *page, void *object, unsigned long addr) { return 0; }
1232
1233static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1234 { return 1; }
1235static inline int check_object(struct kmem_cache *s, struct page *page,
1236 void *object, u8 val) { return 1; }
1237static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1238 struct page *page) {}
1239static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1240static inline unsigned long kmem_cache_flags(unsigned long objsize,
1241 unsigned long flags, const char *name,
1242 void (*ctor)(void *))
1243{
1244 return flags;
1245}
1246#define slub_debug 0
1247
1248#define disable_higher_order_debug 0
1249
1250static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1251 { return 0; }
1252static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1253 { return 0; }
1254static inline void inc_slabs_node(struct kmem_cache *s, int node,
1255 int objects) {}
1256static inline void dec_slabs_node(struct kmem_cache *s, int node,
1257 int objects) {}
1258
1259static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1260 { return 0; }
1261
1262static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1263 void *object) {}
1264
1265static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
1266
1267#endif /* CONFIG_SLUB_DEBUG */
1268
1269/*
1270 * Slab allocation and freeing
1271 */
1272static inline struct page *alloc_slab_page(gfp_t flags, int node,
1273 struct kmem_cache_order_objects oo)
1274{
1275 int order = oo_order(oo);
1276
1277 flags |= __GFP_NOTRACK;
1278
1279 if (node == NUMA_NO_NODE)
1280 return alloc_pages(flags, order);
1281 else
1282 return alloc_pages_exact_node(node, flags, order);
1283}
1284
1285static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1286{
1287 struct page *page;
1288 struct kmem_cache_order_objects oo = s->oo;
1289 gfp_t alloc_gfp;
1290
1291 flags &= gfp_allowed_mask;
1292
1293 if (flags & __GFP_WAIT)
1294 local_irq_enable();
1295
1296 flags |= s->allocflags;
1297
1298 /*
1299 * Let the initial higher-order allocation fail under memory pressure
1300 * so we fall-back to the minimum order allocation.
1301 */
1302 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1303
1304 page = alloc_slab_page(alloc_gfp, node, oo);
1305 if (unlikely(!page)) {
1306 oo = s->min;
1307 /*
1308 * Allocation may have failed due to fragmentation.
1309 * Try a lower order alloc if possible
1310 */
1311 page = alloc_slab_page(flags, node, oo);
1312
1313 if (page)
1314 stat(s, ORDER_FALLBACK);
1315 }
1316
1317 if (flags & __GFP_WAIT)
1318 local_irq_disable();
1319
1320 if (!page)
1321 return NULL;
1322
1323 if (kmemcheck_enabled
1324 && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1325 int pages = 1 << oo_order(oo);
1326
1327 kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1328
1329 /*
1330 * Objects from caches that have a constructor don't get
1331 * cleared when they're allocated, so we need to do it here.
1332 */
1333 if (s->ctor)
1334 kmemcheck_mark_uninitialized_pages(page, pages);
1335 else
1336 kmemcheck_mark_unallocated_pages(page, pages);
1337 }
1338
1339 page->objects = oo_objects(oo);
1340 mod_zone_page_state(page_zone(page),
1341 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1342 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1343 1 << oo_order(oo));
1344
1345 return page;
1346}
1347
1348static void setup_object(struct kmem_cache *s, struct page *page,
1349 void *object)
1350{
1351 setup_object_debug(s, page, object);
1352 if (unlikely(s->ctor))
1353 s->ctor(object);
1354}
1355
1356static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1357{
1358 struct page *page;
1359 void *start;
1360 void *last;
1361 void *p;
1362
1363 BUG_ON(flags & GFP_SLAB_BUG_MASK);
1364
1365 page = allocate_slab(s,
1366 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1367 if (!page)
1368 goto out;
1369
1370 inc_slabs_node(s, page_to_nid(page), page->objects);
1371 page->slab = s;
1372 __SetPageSlab(page);
1373
1374 start = page_address(page);
1375
1376 if (unlikely(s->flags & SLAB_POISON))
1377 memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
1378
1379 last = start;
1380 for_each_object(p, s, start, page->objects) {
1381 setup_object(s, page, last);
1382 set_freepointer(s, last, p);
1383 last = p;
1384 }
1385 setup_object(s, page, last);
1386 set_freepointer(s, last, NULL);
1387
1388 page->freelist = start;
1389 page->inuse = page->objects;
1390 page->frozen = 1;
1391out:
1392 return page;
1393}
1394
1395static void __free_slab(struct kmem_cache *s, struct page *page)
1396{
1397 int order = compound_order(page);
1398 int pages = 1 << order;
1399
1400 if (kmem_cache_debug(s)) {
1401 void *p;
1402
1403 slab_pad_check(s, page);
1404 for_each_object(p, s, page_address(page),
1405 page->objects)
1406 check_object(s, page, p, SLUB_RED_INACTIVE);
1407 }
1408
1409 kmemcheck_free_shadow(page, compound_order(page));
1410
1411 mod_zone_page_state(page_zone(page),
1412 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1413 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1414 -pages);
1415
1416 __ClearPageSlab(page);
1417 reset_page_mapcount(page);
1418 if (current->reclaim_state)
1419 current->reclaim_state->reclaimed_slab += pages;
1420 __free_pages(page, order);
1421}
1422
1423#define need_reserve_slab_rcu \
1424 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1425
1426static void rcu_free_slab(struct rcu_head *h)
1427{
1428 struct page *page;
1429
1430 if (need_reserve_slab_rcu)
1431 page = virt_to_head_page(h);
1432 else
1433 page = container_of((struct list_head *)h, struct page, lru);
1434
1435 __free_slab(page->slab, page);
1436}
1437
1438static void free_slab(struct kmem_cache *s, struct page *page)
1439{
1440 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1441 struct rcu_head *head;
1442
1443 if (need_reserve_slab_rcu) {
1444 int order = compound_order(page);
1445 int offset = (PAGE_SIZE << order) - s->reserved;
1446
1447 VM_BUG_ON(s->reserved != sizeof(*head));
1448 head = page_address(page) + offset;
1449 } else {
1450 /*
1451 * RCU free overloads the RCU head over the LRU
1452 */
1453 head = (void *)&page->lru;
1454 }
1455
1456 call_rcu(head, rcu_free_slab);
1457 } else
1458 __free_slab(s, page);
1459}
1460
1461static void discard_slab(struct kmem_cache *s, struct page *page)
1462{
1463 dec_slabs_node(s, page_to_nid(page), page->objects);
1464 free_slab(s, page);
1465}
1466
1467/*
1468 * Management of partially allocated slabs.
1469 *
1470 * list_lock must be held.
1471 */
1472static inline void add_partial(struct kmem_cache_node *n,
1473 struct page *page, int tail)
1474{
1475 n->nr_partial++;
1476 if (tail == DEACTIVATE_TO_TAIL)
1477 list_add_tail(&page->lru, &n->partial);
1478 else
1479 list_add(&page->lru, &n->partial);
1480}
1481
1482/*
1483 * list_lock must be held.
1484 */
1485static inline void remove_partial(struct kmem_cache_node *n,
1486 struct page *page)
1487{
1488 list_del(&page->lru);
1489 n->nr_partial--;
1490}
1491
1492/*
1493 * Lock slab, remove from the partial list and put the object into the
1494 * per cpu freelist.
1495 *
1496 * Returns a list of objects or NULL if it fails.
1497 *
1498 * Must hold list_lock.
1499 */
1500static inline void *acquire_slab(struct kmem_cache *s,
1501 struct kmem_cache_node *n, struct page *page,
1502 int mode)
1503{
1504 void *freelist;
1505 unsigned long counters;
1506 struct page new;
1507
1508 /*
1509 * Zap the freelist and set the frozen bit.
1510 * The old freelist is the list of objects for the
1511 * per cpu allocation list.
1512 */
1513 do {
1514 freelist = page->freelist;
1515 counters = page->counters;
1516 new.counters = counters;
1517 if (mode) {
1518 new.inuse = page->objects;
1519 new.freelist = NULL;
1520 } else {
1521 new.freelist = freelist;
1522 }
1523
1524 VM_BUG_ON(new.frozen);
1525 new.frozen = 1;
1526
1527 } while (!__cmpxchg_double_slab(s, page,
1528 freelist, counters,
1529 new.freelist, new.counters,
1530 "lock and freeze"));
1531
1532 remove_partial(n, page);
1533 return freelist;
1534}
1535
1536static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1537
1538/*
1539 * Try to allocate a partial slab from a specific node.
1540 */
1541static void *get_partial_node(struct kmem_cache *s,
1542 struct kmem_cache_node *n, struct kmem_cache_cpu *c)
1543{
1544 struct page *page, *page2;
1545 void *object = NULL;
1546
1547 /*
1548 * Racy check. If we mistakenly see no partial slabs then we
1549 * just allocate an empty slab. If we mistakenly try to get a
1550 * partial slab and there is none available then get_partials()
1551 * will return NULL.
1552 */
1553 if (!n || !n->nr_partial)
1554 return NULL;
1555
1556 spin_lock(&n->list_lock);
1557 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1558 void *t = acquire_slab(s, n, page, object == NULL);
1559 int available;
1560
1561 if (!t)
1562 break;
1563
1564 if (!object) {
1565 c->page = page;
1566 c->node = page_to_nid(page);
1567 stat(s, ALLOC_FROM_PARTIAL);
1568 object = t;
1569 available = page->objects - page->inuse;
1570 } else {
1571 available = put_cpu_partial(s, page, 0);
1572 stat(s, CPU_PARTIAL_NODE);
1573 }
1574 if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
1575 break;
1576
1577 }
1578 spin_unlock(&n->list_lock);
1579 return object;
1580}
1581
1582/*
1583 * Get a page from somewhere. Search in increasing NUMA distances.
1584 */
1585static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1586 struct kmem_cache_cpu *c)
1587{
1588#ifdef CONFIG_NUMA
1589 struct zonelist *zonelist;
1590 struct zoneref *z;
1591 struct zone *zone;
1592 enum zone_type high_zoneidx = gfp_zone(flags);
1593 void *object;
1594 unsigned int cpuset_mems_cookie;
1595
1596 /*
1597 * The defrag ratio allows a configuration of the tradeoffs between
1598 * inter node defragmentation and node local allocations. A lower
1599 * defrag_ratio increases the tendency to do local allocations
1600 * instead of attempting to obtain partial slabs from other nodes.
1601 *
1602 * If the defrag_ratio is set to 0 then kmalloc() always
1603 * returns node local objects. If the ratio is higher then kmalloc()
1604 * may return off node objects because partial slabs are obtained
1605 * from other nodes and filled up.
1606 *
1607 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1608 * defrag_ratio = 1000) then every (well almost) allocation will
1609 * first attempt to defrag slab caches on other nodes. This means
1610 * scanning over all nodes to look for partial slabs which may be
1611 * expensive if we do it every time we are trying to find a slab
1612 * with available objects.
1613 */
1614 if (!s->remote_node_defrag_ratio ||
1615 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1616 return NULL;
1617
1618 do {
1619 cpuset_mems_cookie = get_mems_allowed();
1620 zonelist = node_zonelist(slab_node(current->mempolicy), flags);
1621 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1622 struct kmem_cache_node *n;
1623
1624 n = get_node(s, zone_to_nid(zone));
1625
1626 if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1627 n->nr_partial > s->min_partial) {
1628 object = get_partial_node(s, n, c);
1629 if (object) {
1630 /*
1631 * Return the object even if
1632 * put_mems_allowed indicated that
1633 * the cpuset mems_allowed was
1634 * updated in parallel. It's a
1635 * harmless race between the alloc
1636 * and the cpuset update.
1637 */
1638 put_mems_allowed(cpuset_mems_cookie);
1639 return object;
1640 }
1641 }
1642 }
1643 } while (!put_mems_allowed(cpuset_mems_cookie));
1644#endif
1645 return NULL;
1646}
1647
1648/*
1649 * Get a partial page, lock it and return it.
1650 */
1651static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1652 struct kmem_cache_cpu *c)
1653{
1654 void *object;
1655 int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
1656
1657 object = get_partial_node(s, get_node(s, searchnode), c);
1658 if (object || node != NUMA_NO_NODE)
1659 return object;
1660
1661 return get_any_partial(s, flags, c);
1662}
1663
1664#ifdef CONFIG_PREEMPT
1665/*
1666 * Calculate the next globally unique transaction for disambiguiation
1667 * during cmpxchg. The transactions start with the cpu number and are then
1668 * incremented by CONFIG_NR_CPUS.
1669 */
1670#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1671#else
1672/*
1673 * No preemption supported therefore also no need to check for
1674 * different cpus.
1675 */
1676#define TID_STEP 1
1677#endif
1678
1679static inline unsigned long next_tid(unsigned long tid)
1680{
1681 return tid + TID_STEP;
1682}
1683
1684static inline unsigned int tid_to_cpu(unsigned long tid)
1685{
1686 return tid % TID_STEP;
1687}
1688
1689static inline unsigned long tid_to_event(unsigned long tid)
1690{
1691 return tid / TID_STEP;
1692}
1693
1694static inline unsigned int init_tid(int cpu)
1695{
1696 return cpu;
1697}
1698
1699static inline void note_cmpxchg_failure(const char *n,
1700 const struct kmem_cache *s, unsigned long tid)
1701{
1702#ifdef SLUB_DEBUG_CMPXCHG
1703 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1704
1705 printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1706
1707#ifdef CONFIG_PREEMPT
1708 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1709 printk("due to cpu change %d -> %d\n",
1710 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1711 else
1712#endif
1713 if (tid_to_event(tid) != tid_to_event(actual_tid))
1714 printk("due to cpu running other code. Event %ld->%ld\n",
1715 tid_to_event(tid), tid_to_event(actual_tid));
1716 else
1717 printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1718 actual_tid, tid, next_tid(tid));
1719#endif
1720 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1721}
1722
1723void init_kmem_cache_cpus(struct kmem_cache *s)
1724{
1725 int cpu;
1726
1727 for_each_possible_cpu(cpu)
1728 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1729}
1730
1731/*
1732 * Remove the cpu slab
1733 */
1734static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1735{
1736 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1737 struct page *page = c->page;
1738 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1739 int lock = 0;
1740 enum slab_modes l = M_NONE, m = M_NONE;
1741 void *freelist;
1742 void *nextfree;
1743 int tail = DEACTIVATE_TO_HEAD;
1744 struct page new;
1745 struct page old;
1746
1747 if (page->freelist) {
1748 stat(s, DEACTIVATE_REMOTE_FREES);
1749 tail = DEACTIVATE_TO_TAIL;
1750 }
1751
1752 c->tid = next_tid(c->tid);
1753 c->page = NULL;
1754 freelist = c->freelist;
1755 c->freelist = NULL;
1756
1757 /*
1758 * Stage one: Free all available per cpu objects back
1759 * to the page freelist while it is still frozen. Leave the
1760 * last one.
1761 *
1762 * There is no need to take the list->lock because the page
1763 * is still frozen.
1764 */
1765 while (freelist && (nextfree = get_freepointer(s, freelist))) {
1766 void *prior;
1767 unsigned long counters;
1768
1769 do {
1770 prior = page->freelist;
1771 counters = page->counters;
1772 set_freepointer(s, freelist, prior);
1773 new.counters = counters;
1774 new.inuse--;
1775 VM_BUG_ON(!new.frozen);
1776
1777 } while (!__cmpxchg_double_slab(s, page,
1778 prior, counters,
1779 freelist, new.counters,
1780 "drain percpu freelist"));
1781
1782 freelist = nextfree;
1783 }
1784
1785 /*
1786 * Stage two: Ensure that the page is unfrozen while the
1787 * list presence reflects the actual number of objects
1788 * during unfreeze.
1789 *
1790 * We setup the list membership and then perform a cmpxchg
1791 * with the count. If there is a mismatch then the page
1792 * is not unfrozen but the page is on the wrong list.
1793 *
1794 * Then we restart the process which may have to remove
1795 * the page from the list that we just put it on again
1796 * because the number of objects in the slab may have
1797 * changed.
1798 */
1799redo:
1800
1801 old.freelist = page->freelist;
1802 old.counters = page->counters;
1803 VM_BUG_ON(!old.frozen);
1804
1805 /* Determine target state of the slab */
1806 new.counters = old.counters;
1807 if (freelist) {
1808 new.inuse--;
1809 set_freepointer(s, freelist, old.freelist);
1810 new.freelist = freelist;
1811 } else
1812 new.freelist = old.freelist;
1813
1814 new.frozen = 0;
1815
1816 if (!new.inuse && n->nr_partial > s->min_partial)
1817 m = M_FREE;
1818 else if (new.freelist) {
1819 m = M_PARTIAL;
1820 if (!lock) {
1821 lock = 1;
1822 /*
1823 * Taking the spinlock removes the possiblity
1824 * that acquire_slab() will see a slab page that
1825 * is frozen
1826 */
1827 spin_lock(&n->list_lock);
1828 }
1829 } else {
1830 m = M_FULL;
1831 if (kmem_cache_debug(s) && !lock) {
1832 lock = 1;
1833 /*
1834 * This also ensures that the scanning of full
1835 * slabs from diagnostic functions will not see
1836 * any frozen slabs.
1837 */
1838 spin_lock(&n->list_lock);
1839 }
1840 }
1841
1842 if (l != m) {
1843
1844 if (l == M_PARTIAL)
1845
1846 remove_partial(n, page);
1847
1848 else if (l == M_FULL)
1849
1850 remove_full(s, page);
1851
1852 if (m == M_PARTIAL) {
1853
1854 add_partial(n, page, tail);
1855 stat(s, tail);
1856
1857 } else if (m == M_FULL) {
1858
1859 stat(s, DEACTIVATE_FULL);
1860 add_full(s, n, page);
1861
1862 }
1863 }
1864
1865 l = m;
1866 if (!__cmpxchg_double_slab(s, page,
1867 old.freelist, old.counters,
1868 new.freelist, new.counters,
1869 "unfreezing slab"))
1870 goto redo;
1871
1872 if (lock)
1873 spin_unlock(&n->list_lock);
1874
1875 if (m == M_FREE) {
1876 stat(s, DEACTIVATE_EMPTY);
1877 discard_slab(s, page);
1878 stat(s, FREE_SLAB);
1879 }
1880}
1881
1882/* Unfreeze all the cpu partial slabs */
1883static void unfreeze_partials(struct kmem_cache *s)
1884{
1885 struct kmem_cache_node *n = NULL;
1886 struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
1887 struct page *page, *discard_page = NULL;
1888
1889 while ((page = c->partial)) {
1890 enum slab_modes { M_PARTIAL, M_FREE };
1891 enum slab_modes l, m;
1892 struct page new;
1893 struct page old;
1894
1895 c->partial = page->next;
1896 l = M_FREE;
1897
1898 do {
1899
1900 old.freelist = page->freelist;
1901 old.counters = page->counters;
1902 VM_BUG_ON(!old.frozen);
1903
1904 new.counters = old.counters;
1905 new.freelist = old.freelist;
1906
1907 new.frozen = 0;
1908
1909 if (!new.inuse && (!n || n->nr_partial > s->min_partial))
1910 m = M_FREE;
1911 else {
1912 struct kmem_cache_node *n2 = get_node(s,
1913 page_to_nid(page));
1914
1915 m = M_PARTIAL;
1916 if (n != n2) {
1917 if (n)
1918 spin_unlock(&n->list_lock);
1919
1920 n = n2;
1921 spin_lock(&n->list_lock);
1922 }
1923 }
1924
1925 if (l != m) {
1926 if (l == M_PARTIAL) {
1927 remove_partial(n, page);
1928 stat(s, FREE_REMOVE_PARTIAL);
1929 } else {
1930 add_partial(n, page,
1931 DEACTIVATE_TO_TAIL);
1932 stat(s, FREE_ADD_PARTIAL);
1933 }
1934
1935 l = m;
1936 }
1937
1938 } while (!cmpxchg_double_slab(s, page,
1939 old.freelist, old.counters,
1940 new.freelist, new.counters,
1941 "unfreezing slab"));
1942
1943 if (m == M_FREE) {
1944 page->next = discard_page;
1945 discard_page = page;
1946 }
1947 }
1948
1949 if (n)
1950 spin_unlock(&n->list_lock);
1951
1952 while (discard_page) {
1953 page = discard_page;
1954 discard_page = discard_page->next;
1955
1956 stat(s, DEACTIVATE_EMPTY);
1957 discard_slab(s, page);
1958 stat(s, FREE_SLAB);
1959 }
1960}
1961
1962/*
1963 * Put a page that was just frozen (in __slab_free) into a partial page
1964 * slot if available. This is done without interrupts disabled and without
1965 * preemption disabled. The cmpxchg is racy and may put the partial page
1966 * onto a random cpus partial slot.
1967 *
1968 * If we did not find a slot then simply move all the partials to the
1969 * per node partial list.
1970 */
1971int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
1972{
1973 struct page *oldpage;
1974 int pages;
1975 int pobjects;
1976
1977 do {
1978 pages = 0;
1979 pobjects = 0;
1980 oldpage = this_cpu_read(s->cpu_slab->partial);
1981
1982 if (oldpage) {
1983 pobjects = oldpage->pobjects;
1984 pages = oldpage->pages;
1985 if (drain && pobjects > s->cpu_partial) {
1986 unsigned long flags;
1987 /*
1988 * partial array is full. Move the existing
1989 * set to the per node partial list.
1990 */
1991 local_irq_save(flags);
1992 unfreeze_partials(s);
1993 local_irq_restore(flags);
1994 pobjects = 0;
1995 pages = 0;
1996 stat(s, CPU_PARTIAL_DRAIN);
1997 }
1998 }
1999
2000 pages++;
2001 pobjects += page->objects - page->inuse;
2002
2003 page->pages = pages;
2004 page->pobjects = pobjects;
2005 page->next = oldpage;
2006
2007 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
2008 return pobjects;
2009}
2010
2011static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2012{
2013 stat(s, CPUSLAB_FLUSH);
2014 deactivate_slab(s, c);
2015}
2016
2017/*
2018 * Flush cpu slab.
2019 *
2020 * Called from IPI handler with interrupts disabled.
2021 */
2022static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2023{
2024 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2025
2026 if (likely(c)) {
2027 if (c->page)
2028 flush_slab(s, c);
2029
2030 unfreeze_partials(s);
2031 }
2032}
2033
2034static void flush_cpu_slab(void *d)
2035{
2036 struct kmem_cache *s = d;
2037
2038 __flush_cpu_slab(s, smp_processor_id());
2039}
2040
2041static bool has_cpu_slab(int cpu, void *info)
2042{
2043 struct kmem_cache *s = info;
2044 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2045
2046 return c->page || c->partial;
2047}
2048
2049static void flush_all(struct kmem_cache *s)
2050{
2051 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2052}
2053
2054/*
2055 * Check if the objects in a per cpu structure fit numa
2056 * locality expectations.
2057 */
2058static inline int node_match(struct kmem_cache_cpu *c, int node)
2059{
2060#ifdef CONFIG_NUMA
2061 if (node != NUMA_NO_NODE && c->node != node)
2062 return 0;
2063#endif
2064 return 1;
2065}
2066
2067static int count_free(struct page *page)
2068{
2069 return page->objects - page->inuse;
2070}
2071
2072static unsigned long count_partial(struct kmem_cache_node *n,
2073 int (*get_count)(struct page *))
2074{
2075 unsigned long flags;
2076 unsigned long x = 0;
2077 struct page *page;
2078
2079 spin_lock_irqsave(&n->list_lock, flags);
2080 list_for_each_entry(page, &n->partial, lru)
2081 x += get_count(page);
2082 spin_unlock_irqrestore(&n->list_lock, flags);
2083 return x;
2084}
2085
2086static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2087{
2088#ifdef CONFIG_SLUB_DEBUG
2089 return atomic_long_read(&n->total_objects);
2090#else
2091 return 0;
2092#endif
2093}
2094
2095static noinline void
2096slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2097{
2098 int node;
2099
2100 printk(KERN_WARNING
2101 "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2102 nid, gfpflags);
2103 printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
2104 "default order: %d, min order: %d\n", s->name, s->objsize,
2105 s->size, oo_order(s->oo), oo_order(s->min));
2106
2107 if (oo_order(s->min) > get_order(s->objsize))
2108 printk(KERN_WARNING " %s debugging increased min order, use "
2109 "slub_debug=O to disable.\n", s->name);
2110
2111 for_each_online_node(node) {
2112 struct kmem_cache_node *n = get_node(s, node);
2113 unsigned long nr_slabs;
2114 unsigned long nr_objs;
2115 unsigned long nr_free;
2116
2117 if (!n)
2118 continue;
2119
2120 nr_free = count_partial(n, count_free);
2121 nr_slabs = node_nr_slabs(n);
2122 nr_objs = node_nr_objs(n);
2123
2124 printk(KERN_WARNING
2125 " node %d: slabs: %ld, objs: %ld, free: %ld\n",
2126 node, nr_slabs, nr_objs, nr_free);
2127 }
2128}
2129
2130static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2131 int node, struct kmem_cache_cpu **pc)
2132{
2133 void *object;
2134 struct kmem_cache_cpu *c;
2135 struct page *page = new_slab(s, flags, node);
2136
2137 if (page) {
2138 c = __this_cpu_ptr(s->cpu_slab);
2139 if (c->page)
2140 flush_slab(s, c);
2141
2142 /*
2143 * No other reference to the page yet so we can
2144 * muck around with it freely without cmpxchg
2145 */
2146 object = page->freelist;
2147 page->freelist = NULL;
2148
2149 stat(s, ALLOC_SLAB);
2150 c->node = page_to_nid(page);
2151 c->page = page;
2152 *pc = c;
2153 } else
2154 object = NULL;
2155
2156 return object;
2157}
2158
2159/*
2160 * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
2161 * or deactivate the page.
2162 *
2163 * The page is still frozen if the return value is not NULL.
2164 *
2165 * If this function returns NULL then the page has been unfrozen.
2166 */
2167static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2168{
2169 struct page new;
2170 unsigned long counters;
2171 void *freelist;
2172
2173 do {
2174 freelist = page->freelist;
2175 counters = page->counters;
2176 new.counters = counters;
2177 VM_BUG_ON(!new.frozen);
2178
2179 new.inuse = page->objects;
2180 new.frozen = freelist != NULL;
2181
2182 } while (!cmpxchg_double_slab(s, page,
2183 freelist, counters,
2184 NULL, new.counters,
2185 "get_freelist"));
2186
2187 return freelist;
2188}
2189
2190/*
2191 * Slow path. The lockless freelist is empty or we need to perform
2192 * debugging duties.
2193 *
2194 * Processing is still very fast if new objects have been freed to the
2195 * regular freelist. In that case we simply take over the regular freelist
2196 * as the lockless freelist and zap the regular freelist.
2197 *
2198 * If that is not working then we fall back to the partial lists. We take the
2199 * first element of the freelist as the object to allocate now and move the
2200 * rest of the freelist to the lockless freelist.
2201 *
2202 * And if we were unable to get a new slab from the partial slab lists then
2203 * we need to allocate a new slab. This is the slowest path since it involves
2204 * a call to the page allocator and the setup of a new slab.
2205 */
2206static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2207 unsigned long addr, struct kmem_cache_cpu *c)
2208{
2209 void **object;
2210 unsigned long flags;
2211
2212 local_irq_save(flags);
2213#ifdef CONFIG_PREEMPT
2214 /*
2215 * We may have been preempted and rescheduled on a different
2216 * cpu before disabling interrupts. Need to reload cpu area
2217 * pointer.
2218 */
2219 c = this_cpu_ptr(s->cpu_slab);
2220#endif
2221
2222 if (!c->page)
2223 goto new_slab;
2224redo:
2225 if (unlikely(!node_match(c, node))) {
2226 stat(s, ALLOC_NODE_MISMATCH);
2227 deactivate_slab(s, c);
2228 goto new_slab;
2229 }
2230
2231 /* must check again c->freelist in case of cpu migration or IRQ */
2232 object = c->freelist;
2233 if (object)
2234 goto load_freelist;
2235
2236 stat(s, ALLOC_SLOWPATH);
2237
2238 object = get_freelist(s, c->page);
2239
2240 if (!object) {
2241 c->page = NULL;
2242 stat(s, DEACTIVATE_BYPASS);
2243 goto new_slab;
2244 }
2245
2246 stat(s, ALLOC_REFILL);
2247
2248load_freelist:
2249 c->freelist = get_freepointer(s, object);
2250 c->tid = next_tid(c->tid);
2251 local_irq_restore(flags);
2252 return object;
2253
2254new_slab:
2255
2256 if (c->partial) {
2257 c->page = c->partial;
2258 c->partial = c->page->next;
2259 c->node = page_to_nid(c->page);
2260 stat(s, CPU_PARTIAL_ALLOC);
2261 c->freelist = NULL;
2262 goto redo;
2263 }
2264
2265 /* Then do expensive stuff like retrieving pages from the partial lists */
2266 object = get_partial(s, gfpflags, node, c);
2267
2268 if (unlikely(!object)) {
2269
2270 object = new_slab_objects(s, gfpflags, node, &c);
2271
2272 if (unlikely(!object)) {
2273 if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2274 slab_out_of_memory(s, gfpflags, node);
2275
2276 local_irq_restore(flags);
2277 return NULL;
2278 }
2279 }
2280
2281 if (likely(!kmem_cache_debug(s)))
2282 goto load_freelist;
2283
2284 /* Only entered in the debug case */
2285 if (!alloc_debug_processing(s, c->page, object, addr))
2286 goto new_slab; /* Slab failed checks. Next slab needed */
2287
2288 c->freelist = get_freepointer(s, object);
2289 deactivate_slab(s, c);
2290 c->node = NUMA_NO_NODE;
2291 local_irq_restore(flags);
2292 return object;
2293}
2294
2295/*
2296 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2297 * have the fastpath folded into their functions. So no function call
2298 * overhead for requests that can be satisfied on the fastpath.
2299 *
2300 * The fastpath works by first checking if the lockless freelist can be used.
2301 * If not then __slab_alloc is called for slow processing.
2302 *
2303 * Otherwise we can simply pick the next object from the lockless free list.
2304 */
2305static __always_inline void *slab_alloc(struct kmem_cache *s,
2306 gfp_t gfpflags, int node, unsigned long addr)
2307{
2308 void **object;
2309 struct kmem_cache_cpu *c;
2310 unsigned long tid;
2311
2312 if (slab_pre_alloc_hook(s, gfpflags))
2313 return NULL;
2314
2315redo:
2316
2317 /*
2318 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2319 * enabled. We may switch back and forth between cpus while
2320 * reading from one cpu area. That does not matter as long
2321 * as we end up on the original cpu again when doing the cmpxchg.
2322 */
2323 c = __this_cpu_ptr(s->cpu_slab);
2324
2325 /*
2326 * The transaction ids are globally unique per cpu and per operation on
2327 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2328 * occurs on the right processor and that there was no operation on the
2329 * linked list in between.
2330 */
2331 tid = c->tid;
2332 barrier();
2333
2334 object = c->freelist;
2335 if (unlikely(!object || !node_match(c, node)))
2336
2337 object = __slab_alloc(s, gfpflags, node, addr, c);
2338
2339 else {
2340 void *next_object = get_freepointer_safe(s, object);
2341
2342 /*
2343 * The cmpxchg will only match if there was no additional
2344 * operation and if we are on the right processor.
2345 *
2346 * The cmpxchg does the following atomically (without lock semantics!)
2347 * 1. Relocate first pointer to the current per cpu area.
2348 * 2. Verify that tid and freelist have not been changed
2349 * 3. If they were not changed replace tid and freelist
2350 *
2351 * Since this is without lock semantics the protection is only against
2352 * code executing on this cpu *not* from access by other cpus.
2353 */
2354 if (unlikely(!this_cpu_cmpxchg_double(
2355 s->cpu_slab->freelist, s->cpu_slab->tid,
2356 object, tid,
2357 next_object, next_tid(tid)))) {
2358
2359 note_cmpxchg_failure("slab_alloc", s, tid);
2360 goto redo;
2361 }
2362 prefetch_freepointer(s, next_object);
2363 stat(s, ALLOC_FASTPATH);
2364 }
2365
2366 if (unlikely(gfpflags & __GFP_ZERO) && object)
2367 memset(object, 0, s->objsize);
2368
2369 slab_post_alloc_hook(s, gfpflags, object);
2370
2371 return object;
2372}
2373
2374void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2375{
2376 void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
2377
2378 trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
2379
2380 return ret;
2381}
2382EXPORT_SYMBOL(kmem_cache_alloc);
2383
2384#ifdef CONFIG_TRACING
2385void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2386{
2387 void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
2388 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2389 return ret;
2390}
2391EXPORT_SYMBOL(kmem_cache_alloc_trace);
2392
2393void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
2394{
2395 void *ret = kmalloc_order(size, flags, order);
2396 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
2397 return ret;
2398}
2399EXPORT_SYMBOL(kmalloc_order_trace);
2400#endif
2401
2402#ifdef CONFIG_NUMA
2403void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2404{
2405 void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
2406
2407 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2408 s->objsize, s->size, gfpflags, node);
2409
2410 return ret;
2411}
2412EXPORT_SYMBOL(kmem_cache_alloc_node);
2413
2414#ifdef CONFIG_TRACING
2415void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2416 gfp_t gfpflags,
2417 int node, size_t size)
2418{
2419 void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
2420
2421 trace_kmalloc_node(_RET_IP_, ret,
2422 size, s->size, gfpflags, node);
2423 return ret;
2424}
2425EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2426#endif
2427#endif
2428
2429/*
2430 * Slow patch handling. This may still be called frequently since objects
2431 * have a longer lifetime than the cpu slabs in most processing loads.
2432 *
2433 * So we still attempt to reduce cache line usage. Just take the slab
2434 * lock and free the item. If there is no additional partial page
2435 * handling required then we can return immediately.
2436 */
2437static void __slab_free(struct kmem_cache *s, struct page *page,
2438 void *x, unsigned long addr)
2439{
2440 void *prior;
2441 void **object = (void *)x;
2442 int was_frozen;
2443 int inuse;
2444 struct page new;
2445 unsigned long counters;
2446 struct kmem_cache_node *n = NULL;
2447 unsigned long uninitialized_var(flags);
2448
2449 stat(s, FREE_SLOWPATH);
2450
2451 if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
2452 return;
2453
2454 do {
2455 prior = page->freelist;
2456 counters = page->counters;
2457 set_freepointer(s, object, prior);
2458 new.counters = counters;
2459 was_frozen = new.frozen;
2460 new.inuse--;
2461 if ((!new.inuse || !prior) && !was_frozen && !n) {
2462
2463 if (!kmem_cache_debug(s) && !prior)
2464
2465 /*
2466 * Slab was on no list before and will be partially empty
2467 * We can defer the list move and instead freeze it.
2468 */
2469 new.frozen = 1;
2470
2471 else { /* Needs to be taken off a list */
2472
2473 n = get_node(s, page_to_nid(page));
2474 /*
2475 * Speculatively acquire the list_lock.
2476 * If the cmpxchg does not succeed then we may
2477 * drop the list_lock without any processing.
2478 *
2479 * Otherwise the list_lock will synchronize with
2480 * other processors updating the list of slabs.
2481 */
2482 spin_lock_irqsave(&n->list_lock, flags);
2483
2484 }
2485 }
2486 inuse = new.inuse;
2487
2488 } while (!cmpxchg_double_slab(s, page,
2489 prior, counters,
2490 object, new.counters,
2491 "__slab_free"));
2492
2493 if (likely(!n)) {
2494
2495 /*
2496 * If we just froze the page then put it onto the
2497 * per cpu partial list.
2498 */
2499 if (new.frozen && !was_frozen) {
2500 put_cpu_partial(s, page, 1);
2501 stat(s, CPU_PARTIAL_FREE);
2502 }
2503 /*
2504 * The list lock was not taken therefore no list
2505 * activity can be necessary.
2506 */
2507 if (was_frozen)
2508 stat(s, FREE_FROZEN);
2509 return;
2510 }
2511
2512 /*
2513 * was_frozen may have been set after we acquired the list_lock in
2514 * an earlier loop. So we need to check it here again.
2515 */
2516 if (was_frozen)
2517 stat(s, FREE_FROZEN);
2518 else {
2519 if (unlikely(!inuse && n->nr_partial > s->min_partial))
2520 goto slab_empty;
2521
2522 /*
2523 * Objects left in the slab. If it was not on the partial list before
2524 * then add it.
2525 */
2526 if (unlikely(!prior)) {
2527 remove_full(s, page);
2528 add_partial(n, page, DEACTIVATE_TO_TAIL);
2529 stat(s, FREE_ADD_PARTIAL);
2530 }
2531 }
2532 spin_unlock_irqrestore(&n->list_lock, flags);
2533 return;
2534
2535slab_empty:
2536 if (prior) {
2537 /*
2538 * Slab on the partial list.
2539 */
2540 remove_partial(n, page);
2541 stat(s, FREE_REMOVE_PARTIAL);
2542 } else
2543 /* Slab must be on the full list */
2544 remove_full(s, page);
2545
2546 spin_unlock_irqrestore(&n->list_lock, flags);
2547 stat(s, FREE_SLAB);
2548 discard_slab(s, page);
2549}
2550
2551/*
2552 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2553 * can perform fastpath freeing without additional function calls.
2554 *
2555 * The fastpath is only possible if we are freeing to the current cpu slab
2556 * of this processor. This typically the case if we have just allocated
2557 * the item before.
2558 *
2559 * If fastpath is not possible then fall back to __slab_free where we deal
2560 * with all sorts of special processing.
2561 */
2562static __always_inline void slab_free(struct kmem_cache *s,
2563 struct page *page, void *x, unsigned long addr)
2564{
2565 void **object = (void *)x;
2566 struct kmem_cache_cpu *c;
2567 unsigned long tid;
2568
2569 slab_free_hook(s, x);
2570
2571redo:
2572 /*
2573 * Determine the currently cpus per cpu slab.
2574 * The cpu may change afterward. However that does not matter since
2575 * data is retrieved via this pointer. If we are on the same cpu
2576 * during the cmpxchg then the free will succedd.
2577 */
2578 c = __this_cpu_ptr(s->cpu_slab);
2579
2580 tid = c->tid;
2581 barrier();
2582
2583 if (likely(page == c->page)) {
2584 set_freepointer(s, object, c->freelist);
2585
2586 if (unlikely(!this_cpu_cmpxchg_double(
2587 s->cpu_slab->freelist, s->cpu_slab->tid,
2588 c->freelist, tid,
2589 object, next_tid(tid)))) {
2590
2591 note_cmpxchg_failure("slab_free", s, tid);
2592 goto redo;
2593 }
2594 stat(s, FREE_FASTPATH);
2595 } else
2596 __slab_free(s, page, x, addr);
2597
2598}
2599
2600void kmem_cache_free(struct kmem_cache *s, void *x)
2601{
2602 struct page *page;
2603
2604 page = virt_to_head_page(x);
2605
2606 slab_free(s, page, x, _RET_IP_);
2607
2608 trace_kmem_cache_free(_RET_IP_, x);
2609}
2610EXPORT_SYMBOL(kmem_cache_free);
2611
2612/*
2613 * Object placement in a slab is made very easy because we always start at
2614 * offset 0. If we tune the size of the object to the alignment then we can
2615 * get the required alignment by putting one properly sized object after
2616 * another.
2617 *
2618 * Notice that the allocation order determines the sizes of the per cpu
2619 * caches. Each processor has always one slab available for allocations.
2620 * Increasing the allocation order reduces the number of times that slabs
2621 * must be moved on and off the partial lists and is therefore a factor in
2622 * locking overhead.
2623 */
2624
2625/*
2626 * Mininum / Maximum order of slab pages. This influences locking overhead
2627 * and slab fragmentation. A higher order reduces the number of partial slabs
2628 * and increases the number of allocations possible without having to
2629 * take the list_lock.
2630 */
2631static int slub_min_order;
2632static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2633static int slub_min_objects;
2634
2635/*
2636 * Merge control. If this is set then no merging of slab caches will occur.
2637 * (Could be removed. This was introduced to pacify the merge skeptics.)
2638 */
2639static int slub_nomerge;
2640
2641/*
2642 * Calculate the order of allocation given an slab object size.
2643 *
2644 * The order of allocation has significant impact on performance and other
2645 * system components. Generally order 0 allocations should be preferred since
2646 * order 0 does not cause fragmentation in the page allocator. Larger objects
2647 * be problematic to put into order 0 slabs because there may be too much
2648 * unused space left. We go to a higher order if more than 1/16th of the slab
2649 * would be wasted.
2650 *
2651 * In order to reach satisfactory performance we must ensure that a minimum
2652 * number of objects is in one slab. Otherwise we may generate too much
2653 * activity on the partial lists which requires taking the list_lock. This is
2654 * less a concern for large slabs though which are rarely used.
2655 *
2656 * slub_max_order specifies the order where we begin to stop considering the
2657 * number of objects in a slab as critical. If we reach slub_max_order then
2658 * we try to keep the page order as low as possible. So we accept more waste
2659 * of space in favor of a small page order.
2660 *
2661 * Higher order allocations also allow the placement of more objects in a
2662 * slab and thereby reduce object handling overhead. If the user has
2663 * requested a higher mininum order then we start with that one instead of
2664 * the smallest order which will fit the object.
2665 */
2666static inline int slab_order(int size, int min_objects,
2667 int max_order, int fract_leftover, int reserved)
2668{
2669 int order;
2670 int rem;
2671 int min_order = slub_min_order;
2672
2673 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2674 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2675
2676 for (order = max(min_order,
2677 fls(min_objects * size - 1) - PAGE_SHIFT);
2678 order <= max_order; order++) {
2679
2680 unsigned long slab_size = PAGE_SIZE << order;
2681
2682 if (slab_size < min_objects * size + reserved)
2683 continue;
2684
2685 rem = (slab_size - reserved) % size;
2686
2687 if (rem <= slab_size / fract_leftover)
2688 break;
2689
2690 }
2691
2692 return order;
2693}
2694
2695static inline int calculate_order(int size, int reserved)
2696{
2697 int order;
2698 int min_objects;
2699 int fraction;
2700 int max_objects;
2701
2702 /*
2703 * Attempt to find best configuration for a slab. This
2704 * works by first attempting to generate a layout with
2705 * the best configuration and backing off gradually.
2706 *
2707 * First we reduce the acceptable waste in a slab. Then
2708 * we reduce the minimum objects required in a slab.
2709 */
2710 min_objects = slub_min_objects;
2711 if (!min_objects)
2712 min_objects = 4 * (fls(nr_cpu_ids) + 1);
2713 max_objects = order_objects(slub_max_order, size, reserved);
2714 min_objects = min(min_objects, max_objects);
2715
2716 while (min_objects > 1) {
2717 fraction = 16;
2718 while (fraction >= 4) {
2719 order = slab_order(size, min_objects,
2720 slub_max_order, fraction, reserved);
2721 if (order <= slub_max_order)
2722 return order;
2723 fraction /= 2;
2724 }
2725 min_objects--;
2726 }
2727
2728 /*
2729 * We were unable to place multiple objects in a slab. Now
2730 * lets see if we can place a single object there.
2731 */
2732 order = slab_order(size, 1, slub_max_order, 1, reserved);
2733 if (order <= slub_max_order)
2734 return order;
2735
2736 /*
2737 * Doh this slab cannot be placed using slub_max_order.
2738 */
2739 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2740 if (order < MAX_ORDER)
2741 return order;
2742 return -ENOSYS;
2743}
2744
2745/*
2746 * Figure out what the alignment of the objects will be.
2747 */
2748static unsigned long calculate_alignment(unsigned long flags,
2749 unsigned long align, unsigned long size)
2750{
2751 /*
2752 * If the user wants hardware cache aligned objects then follow that
2753 * suggestion if the object is sufficiently large.
2754 *
2755 * The hardware cache alignment cannot override the specified
2756 * alignment though. If that is greater then use it.
2757 */
2758 if (flags & SLAB_HWCACHE_ALIGN) {
2759 unsigned long ralign = cache_line_size();
2760 while (size <= ralign / 2)
2761 ralign /= 2;
2762 align = max(align, ralign);
2763 }
2764
2765 if (align < ARCH_SLAB_MINALIGN)
2766 align = ARCH_SLAB_MINALIGN;
2767
2768 return ALIGN(align, sizeof(void *));
2769}
2770
2771static void
2772init_kmem_cache_node(struct kmem_cache_node *n)
2773{
2774 n->nr_partial = 0;
2775 spin_lock_init(&n->list_lock);
2776 INIT_LIST_HEAD(&n->partial);
2777#ifdef CONFIG_SLUB_DEBUG
2778 atomic_long_set(&n->nr_slabs, 0);
2779 atomic_long_set(&n->total_objects, 0);
2780 INIT_LIST_HEAD(&n->full);
2781#endif
2782}
2783
2784static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2785{
2786 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2787 SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
2788
2789 /*
2790 * Must align to double word boundary for the double cmpxchg
2791 * instructions to work; see __pcpu_double_call_return_bool().
2792 */
2793 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2794 2 * sizeof(void *));
2795
2796 if (!s->cpu_slab)
2797 return 0;
2798
2799 init_kmem_cache_cpus(s);
2800
2801 return 1;
2802}
2803
2804static struct kmem_cache *kmem_cache_node;
2805
2806/*
2807 * No kmalloc_node yet so do it by hand. We know that this is the first
2808 * slab on the node for this slabcache. There are no concurrent accesses
2809 * possible.
2810 *
2811 * Note that this function only works on the kmalloc_node_cache
2812 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2813 * memory on a fresh node that has no slab structures yet.
2814 */
2815static void early_kmem_cache_node_alloc(int node)
2816{
2817 struct page *page;
2818 struct kmem_cache_node *n;
2819
2820 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2821
2822 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2823
2824 BUG_ON(!page);
2825 if (page_to_nid(page) != node) {
2826 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2827 "node %d\n", node);
2828 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2829 "in order to be able to continue\n");
2830 }
2831
2832 n = page->freelist;
2833 BUG_ON(!n);
2834 page->freelist = get_freepointer(kmem_cache_node, n);
2835 page->inuse = 1;
2836 page->frozen = 0;
2837 kmem_cache_node->node[node] = n;
2838#ifdef CONFIG_SLUB_DEBUG
2839 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2840 init_tracking(kmem_cache_node, n);
2841#endif
2842 init_kmem_cache_node(n);
2843 inc_slabs_node(kmem_cache_node, node, page->objects);
2844
2845 add_partial(n, page, DEACTIVATE_TO_HEAD);
2846}
2847
2848static void free_kmem_cache_nodes(struct kmem_cache *s)
2849{
2850 int node;
2851
2852 for_each_node_state(node, N_NORMAL_MEMORY) {
2853 struct kmem_cache_node *n = s->node[node];
2854
2855 if (n)
2856 kmem_cache_free(kmem_cache_node, n);
2857
2858 s->node[node] = NULL;
2859 }
2860}
2861
2862static int init_kmem_cache_nodes(struct kmem_cache *s)
2863{
2864 int node;
2865
2866 for_each_node_state(node, N_NORMAL_MEMORY) {
2867 struct kmem_cache_node *n;
2868
2869 if (slab_state == DOWN) {
2870 early_kmem_cache_node_alloc(node);
2871 continue;
2872 }
2873 n = kmem_cache_alloc_node(kmem_cache_node,
2874 GFP_KERNEL, node);
2875
2876 if (!n) {
2877 free_kmem_cache_nodes(s);
2878 return 0;
2879 }
2880
2881 s->node[node] = n;
2882 init_kmem_cache_node(n);
2883 }
2884 return 1;
2885}
2886
2887static void set_min_partial(struct kmem_cache *s, unsigned long min)
2888{
2889 if (min < MIN_PARTIAL)
2890 min = MIN_PARTIAL;
2891 else if (min > MAX_PARTIAL)
2892 min = MAX_PARTIAL;
2893 s->min_partial = min;
2894}
2895
2896/*
2897 * calculate_sizes() determines the order and the distribution of data within
2898 * a slab object.
2899 */
2900static int calculate_sizes(struct kmem_cache *s, int forced_order)
2901{
2902 unsigned long flags = s->flags;
2903 unsigned long size = s->objsize;
2904 unsigned long align = s->align;
2905 int order;
2906
2907 /*
2908 * Round up object size to the next word boundary. We can only
2909 * place the free pointer at word boundaries and this determines
2910 * the possible location of the free pointer.
2911 */
2912 size = ALIGN(size, sizeof(void *));
2913
2914#ifdef CONFIG_SLUB_DEBUG
2915 /*
2916 * Determine if we can poison the object itself. If the user of
2917 * the slab may touch the object after free or before allocation
2918 * then we should never poison the object itself.
2919 */
2920 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2921 !s->ctor)
2922 s->flags |= __OBJECT_POISON;
2923 else
2924 s->flags &= ~__OBJECT_POISON;
2925
2926
2927 /*
2928 * If we are Redzoning then check if there is some space between the
2929 * end of the object and the free pointer. If not then add an
2930 * additional word to have some bytes to store Redzone information.
2931 */
2932 if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2933 size += sizeof(void *);
2934#endif
2935
2936 /*
2937 * With that we have determined the number of bytes in actual use
2938 * by the object. This is the potential offset to the free pointer.
2939 */
2940 s->inuse = size;
2941
2942 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2943 s->ctor)) {
2944 /*
2945 * Relocate free pointer after the object if it is not
2946 * permitted to overwrite the first word of the object on
2947 * kmem_cache_free.
2948 *
2949 * This is the case if we do RCU, have a constructor or
2950 * destructor or are poisoning the objects.
2951 */
2952 s->offset = size;
2953 size += sizeof(void *);
2954 }
2955
2956#ifdef CONFIG_SLUB_DEBUG
2957 if (flags & SLAB_STORE_USER)
2958 /*
2959 * Need to store information about allocs and frees after
2960 * the object.
2961 */
2962 size += 2 * sizeof(struct track);
2963
2964 if (flags & SLAB_RED_ZONE)
2965 /*
2966 * Add some empty padding so that we can catch
2967 * overwrites from earlier objects rather than let
2968 * tracking information or the free pointer be
2969 * corrupted if a user writes before the start
2970 * of the object.
2971 */
2972 size += sizeof(void *);
2973#endif
2974
2975 /*
2976 * Determine the alignment based on various parameters that the
2977 * user specified and the dynamic determination of cache line size
2978 * on bootup.
2979 */
2980 align = calculate_alignment(flags, align, s->objsize);
2981 s->align = align;
2982
2983 /*
2984 * SLUB stores one object immediately after another beginning from
2985 * offset 0. In order to align the objects we have to simply size
2986 * each object to conform to the alignment.
2987 */
2988 size = ALIGN(size, align);
2989 s->size = size;
2990 if (forced_order >= 0)
2991 order = forced_order;
2992 else
2993 order = calculate_order(size, s->reserved);
2994
2995 if (order < 0)
2996 return 0;
2997
2998 s->allocflags = 0;
2999 if (order)
3000 s->allocflags |= __GFP_COMP;
3001
3002 if (s->flags & SLAB_CACHE_DMA)
3003 s->allocflags |= SLUB_DMA;
3004
3005 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3006 s->allocflags |= __GFP_RECLAIMABLE;
3007
3008 /*
3009 * Determine the number of objects per slab
3010 */
3011 s->oo = oo_make(order, size, s->reserved);
3012 s->min = oo_make(get_order(size), size, s->reserved);
3013 if (oo_objects(s->oo) > oo_objects(s->max))
3014 s->max = s->oo;
3015
3016 return !!oo_objects(s->oo);
3017
3018}
3019
3020static int kmem_cache_open(struct kmem_cache *s,
3021 const char *name, size_t size,
3022 size_t align, unsigned long flags,
3023 void (*ctor)(void *))
3024{
3025 memset(s, 0, kmem_size);
3026 s->name = name;
3027 s->ctor = ctor;
3028 s->objsize = size;
3029 s->align = align;
3030 s->flags = kmem_cache_flags(size, flags, name, ctor);
3031 s->reserved = 0;
3032
3033 if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3034 s->reserved = sizeof(struct rcu_head);
3035
3036 if (!calculate_sizes(s, -1))
3037 goto error;
3038 if (disable_higher_order_debug) {
3039 /*
3040 * Disable debugging flags that store metadata if the min slab
3041 * order increased.
3042 */
3043 if (get_order(s->size) > get_order(s->objsize)) {
3044 s->flags &= ~DEBUG_METADATA_FLAGS;
3045 s->offset = 0;
3046 if (!calculate_sizes(s, -1))
3047 goto error;
3048 }
3049 }
3050
3051#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3052 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3053 if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
3054 /* Enable fast mode */
3055 s->flags |= __CMPXCHG_DOUBLE;
3056#endif
3057
3058 /*
3059 * The larger the object size is, the more pages we want on the partial
3060 * list to avoid pounding the page allocator excessively.
3061 */
3062 set_min_partial(s, ilog2(s->size) / 2);
3063
3064 /*
3065 * cpu_partial determined the maximum number of objects kept in the
3066 * per cpu partial lists of a processor.
3067 *
3068 * Per cpu partial lists mainly contain slabs that just have one
3069 * object freed. If they are used for allocation then they can be
3070 * filled up again with minimal effort. The slab will never hit the
3071 * per node partial lists and therefore no locking will be required.
3072 *
3073 * This setting also determines
3074 *
3075 * A) The number of objects from per cpu partial slabs dumped to the
3076 * per node list when we reach the limit.
3077 * B) The number of objects in cpu partial slabs to extract from the
3078 * per node list when we run out of per cpu objects. We only fetch 50%
3079 * to keep some capacity around for frees.
3080 */
3081 if (kmem_cache_debug(s))
3082 s->cpu_partial = 0;
3083 else if (s->size >= PAGE_SIZE)
3084 s->cpu_partial = 2;
3085 else if (s->size >= 1024)
3086 s->cpu_partial = 6;
3087 else if (s->size >= 256)
3088 s->cpu_partial = 13;
3089 else
3090 s->cpu_partial = 30;
3091
3092 s->refcount = 1;
3093#ifdef CONFIG_NUMA
3094 s->remote_node_defrag_ratio = 1000;
3095#endif
3096 if (!init_kmem_cache_nodes(s))
3097 goto error;
3098
3099 if (alloc_kmem_cache_cpus(s))
3100 return 1;
3101
3102 free_kmem_cache_nodes(s);
3103error:
3104 if (flags & SLAB_PANIC)
3105 panic("Cannot create slab %s size=%lu realsize=%u "
3106 "order=%u offset=%u flags=%lx\n",
3107 s->name, (unsigned long)size, s->size, oo_order(s->oo),
3108 s->offset, flags);
3109 return 0;
3110}
3111
3112/*
3113 * Determine the size of a slab object
3114 */
3115unsigned int kmem_cache_size(struct kmem_cache *s)
3116{
3117 return s->objsize;
3118}
3119EXPORT_SYMBOL(kmem_cache_size);
3120
3121static void list_slab_objects(struct kmem_cache *s, struct page *page,
3122 const char *text)
3123{
3124#ifdef CONFIG_SLUB_DEBUG
3125 void *addr = page_address(page);
3126 void *p;
3127 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3128 sizeof(long), GFP_ATOMIC);
3129 if (!map)
3130 return;
3131 slab_err(s, page, "%s", text);
3132 slab_lock(page);
3133
3134 get_map(s, page, map);
3135 for_each_object(p, s, addr, page->objects) {
3136
3137 if (!test_bit(slab_index(p, s, addr), map)) {
3138 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
3139 p, p - addr);
3140 print_tracking(s, p);
3141 }
3142 }
3143 slab_unlock(page);
3144 kfree(map);
3145#endif
3146}
3147
3148/*
3149 * Attempt to free all partial slabs on a node.
3150 * This is called from kmem_cache_close(). We must be the last thread
3151 * using the cache and therefore we do not need to lock anymore.
3152 */
3153static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3154{
3155 struct page *page, *h;
3156
3157 list_for_each_entry_safe(page, h, &n->partial, lru) {
3158 if (!page->inuse) {
3159 remove_partial(n, page);
3160 discard_slab(s, page);
3161 } else {
3162 list_slab_objects(s, page,
3163 "Objects remaining on kmem_cache_close()");
3164 }
3165 }
3166}
3167
3168/*
3169 * Release all resources used by a slab cache.
3170 */
3171static inline int kmem_cache_close(struct kmem_cache *s)
3172{
3173 int node;
3174
3175 flush_all(s);
3176 free_percpu(s->cpu_slab);
3177 /* Attempt to free all objects */
3178 for_each_node_state(node, N_NORMAL_MEMORY) {
3179 struct kmem_cache_node *n = get_node(s, node);
3180
3181 free_partial(s, n);
3182 if (n->nr_partial || slabs_node(s, node))
3183 return 1;
3184 }
3185 free_kmem_cache_nodes(s);
3186 return 0;
3187}
3188
3189/*
3190 * Close a cache and release the kmem_cache structure
3191 * (must be used for caches created using kmem_cache_create)
3192 */
3193void kmem_cache_destroy(struct kmem_cache *s)
3194{
3195 down_write(&slub_lock);
3196 s->refcount--;
3197 if (!s->refcount) {
3198 list_del(&s->list);
3199 up_write(&slub_lock);
3200 if (kmem_cache_close(s)) {
3201 printk(KERN_ERR "SLUB %s: %s called for cache that "
3202 "still has objects.\n", s->name, __func__);
3203 dump_stack();
3204 }
3205 if (s->flags & SLAB_DESTROY_BY_RCU)
3206 rcu_barrier();
3207 sysfs_slab_remove(s);
3208 } else
3209 up_write(&slub_lock);
3210}
3211EXPORT_SYMBOL(kmem_cache_destroy);
3212
3213/********************************************************************
3214 * Kmalloc subsystem
3215 *******************************************************************/
3216
3217struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
3218EXPORT_SYMBOL(kmalloc_caches);
3219
3220static struct kmem_cache *kmem_cache;
3221
3222#ifdef CONFIG_ZONE_DMA
3223static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
3224#endif
3225
3226static int __init setup_slub_min_order(char *str)
3227{
3228 get_option(&str, &slub_min_order);
3229
3230 return 1;
3231}
3232
3233__setup("slub_min_order=", setup_slub_min_order);
3234
3235static int __init setup_slub_max_order(char *str)
3236{
3237 get_option(&str, &slub_max_order);
3238 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3239
3240 return 1;
3241}
3242
3243__setup("slub_max_order=", setup_slub_max_order);
3244
3245static int __init setup_slub_min_objects(char *str)
3246{
3247 get_option(&str, &slub_min_objects);
3248
3249 return 1;
3250}
3251
3252__setup("slub_min_objects=", setup_slub_min_objects);
3253
3254static int __init setup_slub_nomerge(char *str)
3255{
3256 slub_nomerge = 1;
3257 return 1;
3258}
3259
3260__setup("slub_nomerge", setup_slub_nomerge);
3261
3262static struct kmem_cache *__init create_kmalloc_cache(const char *name,
3263 int size, unsigned int flags)
3264{
3265 struct kmem_cache *s;
3266
3267 s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3268
3269 /*
3270 * This function is called with IRQs disabled during early-boot on
3271 * single CPU so there's no need to take slub_lock here.
3272 */
3273 if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
3274 flags, NULL))
3275 goto panic;
3276
3277 list_add(&s->list, &slab_caches);
3278 return s;
3279
3280panic:
3281 panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
3282 return NULL;
3283}
3284
3285/*
3286 * Conversion table for small slabs sizes / 8 to the index in the
3287 * kmalloc array. This is necessary for slabs < 192 since we have non power
3288 * of two cache sizes there. The size of larger slabs can be determined using
3289 * fls.
3290 */
3291static s8 size_index[24] = {
3292 3, /* 8 */
3293 4, /* 16 */
3294 5, /* 24 */
3295 5, /* 32 */
3296 6, /* 40 */
3297 6, /* 48 */
3298 6, /* 56 */
3299 6, /* 64 */
3300 1, /* 72 */
3301 1, /* 80 */
3302 1, /* 88 */
3303 1, /* 96 */
3304 7, /* 104 */
3305 7, /* 112 */
3306 7, /* 120 */
3307 7, /* 128 */
3308 2, /* 136 */
3309 2, /* 144 */
3310 2, /* 152 */
3311 2, /* 160 */
3312 2, /* 168 */
3313 2, /* 176 */
3314 2, /* 184 */
3315 2 /* 192 */
3316};
3317
3318static inline int size_index_elem(size_t bytes)
3319{
3320 return (bytes - 1) / 8;
3321}
3322
3323static struct kmem_cache *get_slab(size_t size, gfp_t flags)
3324{
3325 int index;
3326
3327 if (size <= 192) {
3328 if (!size)
3329 return ZERO_SIZE_PTR;
3330
3331 index = size_index[size_index_elem(size)];
3332 } else
3333 index = fls(size - 1);
3334
3335#ifdef CONFIG_ZONE_DMA
3336 if (unlikely((flags & SLUB_DMA)))
3337 return kmalloc_dma_caches[index];
3338
3339#endif
3340 return kmalloc_caches[index];
3341}
3342
3343void *__kmalloc(size_t size, gfp_t flags)
3344{
3345 struct kmem_cache *s;
3346 void *ret;
3347
3348 if (unlikely(size > SLUB_MAX_SIZE))
3349 return kmalloc_large(size, flags);
3350
3351 s = get_slab(size, flags);
3352
3353 if (unlikely(ZERO_OR_NULL_PTR(s)))
3354 return s;
3355
3356 ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
3357
3358 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3359
3360 return ret;
3361}
3362EXPORT_SYMBOL(__kmalloc);
3363
3364#ifdef CONFIG_NUMA
3365static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3366{
3367 struct page *page;
3368 void *ptr = NULL;
3369
3370 flags |= __GFP_COMP | __GFP_NOTRACK;
3371 page = alloc_pages_node(node, flags, get_order(size));
3372 if (page)
3373 ptr = page_address(page);
3374
3375 kmemleak_alloc(ptr, size, 1, flags);
3376 return ptr;
3377}
3378
3379void *__kmalloc_node(size_t size, gfp_t flags, int node)
3380{
3381 struct kmem_cache *s;
3382 void *ret;
3383
3384 if (unlikely(size > SLUB_MAX_SIZE)) {
3385 ret = kmalloc_large_node(size, flags, node);
3386
3387 trace_kmalloc_node(_RET_IP_, ret,
3388 size, PAGE_SIZE << get_order(size),
3389 flags, node);
3390
3391 return ret;
3392 }
3393
3394 s = get_slab(size, flags);
3395
3396 if (unlikely(ZERO_OR_NULL_PTR(s)))
3397 return s;
3398
3399 ret = slab_alloc(s, flags, node, _RET_IP_);
3400
3401 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3402
3403 return ret;
3404}
3405EXPORT_SYMBOL(__kmalloc_node);
3406#endif
3407
3408size_t ksize(const void *object)
3409{
3410 struct page *page;
3411
3412 if (unlikely(object == ZERO_SIZE_PTR))
3413 return 0;
3414
3415 page = virt_to_head_page(object);
3416
3417 if (unlikely(!PageSlab(page))) {
3418 WARN_ON(!PageCompound(page));
3419 return PAGE_SIZE << compound_order(page);
3420 }
3421
3422 return slab_ksize(page->slab);
3423}
3424EXPORT_SYMBOL(ksize);
3425
3426#ifdef CONFIG_SLUB_DEBUG
3427bool verify_mem_not_deleted(const void *x)
3428{
3429 struct page *page;
3430 void *object = (void *)x;
3431 unsigned long flags;
3432 bool rv;
3433
3434 if (unlikely(ZERO_OR_NULL_PTR(x)))
3435 return false;
3436
3437 local_irq_save(flags);
3438
3439 page = virt_to_head_page(x);
3440 if (unlikely(!PageSlab(page))) {
3441 /* maybe it was from stack? */
3442 rv = true;
3443 goto out_unlock;
3444 }
3445
3446 slab_lock(page);
3447 if (on_freelist(page->slab, page, object)) {
3448 object_err(page->slab, page, object, "Object is on free-list");
3449 rv = false;
3450 } else {
3451 rv = true;
3452 }
3453 slab_unlock(page);
3454
3455out_unlock:
3456 local_irq_restore(flags);
3457 return rv;
3458}
3459EXPORT_SYMBOL(verify_mem_not_deleted);
3460#endif
3461
3462void kfree(const void *x)
3463{
3464 struct page *page;
3465 void *object = (void *)x;
3466
3467 trace_kfree(_RET_IP_, x);
3468
3469 if (unlikely(ZERO_OR_NULL_PTR(x)))
3470 return;
3471
3472 page = virt_to_head_page(x);
3473 if (unlikely(!PageSlab(page))) {
3474 BUG_ON(!PageCompound(page));
3475 kmemleak_free(x);
3476 put_page(page);
3477 return;
3478 }
3479 slab_free(page->slab, page, object, _RET_IP_);
3480}
3481EXPORT_SYMBOL(kfree);
3482
3483/*
3484 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3485 * the remaining slabs by the number of items in use. The slabs with the
3486 * most items in use come first. New allocations will then fill those up
3487 * and thus they can be removed from the partial lists.
3488 *
3489 * The slabs with the least items are placed last. This results in them
3490 * being allocated from last increasing the chance that the last objects
3491 * are freed in them.
3492 */
3493int kmem_cache_shrink(struct kmem_cache *s)
3494{
3495 int node;
3496 int i;
3497 struct kmem_cache_node *n;
3498 struct page *page;
3499 struct page *t;
3500 int objects = oo_objects(s->max);
3501 struct list_head *slabs_by_inuse =
3502 kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3503 unsigned long flags;
3504
3505 if (!slabs_by_inuse)
3506 return -ENOMEM;
3507
3508 flush_all(s);
3509 for_each_node_state(node, N_NORMAL_MEMORY) {
3510 n = get_node(s, node);
3511
3512 if (!n->nr_partial)
3513 continue;
3514
3515 for (i = 0; i < objects; i++)
3516 INIT_LIST_HEAD(slabs_by_inuse + i);
3517
3518 spin_lock_irqsave(&n->list_lock, flags);
3519
3520 /*
3521 * Build lists indexed by the items in use in each slab.
3522 *
3523 * Note that concurrent frees may occur while we hold the
3524 * list_lock. page->inuse here is the upper limit.
3525 */
3526 list_for_each_entry_safe(page, t, &n->partial, lru) {
3527 list_move(&page->lru, slabs_by_inuse + page->inuse);
3528 if (!page->inuse)
3529 n->nr_partial--;
3530 }
3531
3532 /*
3533 * Rebuild the partial list with the slabs filled up most
3534 * first and the least used slabs at the end.
3535 */
3536 for (i = objects - 1; i > 0; i--)
3537 list_splice(slabs_by_inuse + i, n->partial.prev);
3538
3539 spin_unlock_irqrestore(&n->list_lock, flags);
3540
3541 /* Release empty slabs */
3542 list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
3543 discard_slab(s, page);
3544 }
3545
3546 kfree(slabs_by_inuse);
3547 return 0;
3548}
3549EXPORT_SYMBOL(kmem_cache_shrink);
3550
3551#if defined(CONFIG_MEMORY_HOTPLUG)
3552static int slab_mem_going_offline_callback(void *arg)
3553{
3554 struct kmem_cache *s;
3555
3556 down_read(&slub_lock);
3557 list_for_each_entry(s, &slab_caches, list)
3558 kmem_cache_shrink(s);
3559 up_read(&slub_lock);
3560
3561 return 0;
3562}
3563
3564static void slab_mem_offline_callback(void *arg)
3565{
3566 struct kmem_cache_node *n;
3567 struct kmem_cache *s;
3568 struct memory_notify *marg = arg;
3569 int offline_node;
3570
3571 offline_node = marg->status_change_nid;
3572
3573 /*
3574 * If the node still has available memory. we need kmem_cache_node
3575 * for it yet.
3576 */
3577 if (offline_node < 0)
3578 return;
3579
3580 down_read(&slub_lock);
3581 list_for_each_entry(s, &slab_caches, list) {
3582 n = get_node(s, offline_node);
3583 if (n) {
3584 /*
3585 * if n->nr_slabs > 0, slabs still exist on the node
3586 * that is going down. We were unable to free them,
3587 * and offline_pages() function shouldn't call this
3588 * callback. So, we must fail.
3589 */
3590 BUG_ON(slabs_node(s, offline_node));
3591
3592 s->node[offline_node] = NULL;
3593 kmem_cache_free(kmem_cache_node, n);
3594 }
3595 }
3596 up_read(&slub_lock);
3597}
3598
3599static int slab_mem_going_online_callback(void *arg)
3600{
3601 struct kmem_cache_node *n;
3602 struct kmem_cache *s;
3603 struct memory_notify *marg = arg;
3604 int nid = marg->status_change_nid;
3605 int ret = 0;
3606
3607 /*
3608 * If the node's memory is already available, then kmem_cache_node is
3609 * already created. Nothing to do.
3610 */
3611 if (nid < 0)
3612 return 0;
3613
3614 /*
3615 * We are bringing a node online. No memory is available yet. We must
3616 * allocate a kmem_cache_node structure in order to bring the node
3617 * online.
3618 */
3619 down_read(&slub_lock);
3620 list_for_each_entry(s, &slab_caches, list) {
3621 /*
3622 * XXX: kmem_cache_alloc_node will fallback to other nodes
3623 * since memory is not yet available from the node that
3624 * is brought up.
3625 */
3626 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3627 if (!n) {
3628 ret = -ENOMEM;
3629 goto out;
3630 }
3631 init_kmem_cache_node(n);
3632 s->node[nid] = n;
3633 }
3634out:
3635 up_read(&slub_lock);
3636 return ret;
3637}
3638
3639static int slab_memory_callback(struct notifier_block *self,
3640 unsigned long action, void *arg)
3641{
3642 int ret = 0;
3643
3644 switch (action) {
3645 case MEM_GOING_ONLINE:
3646 ret = slab_mem_going_online_callback(arg);
3647 break;
3648 case MEM_GOING_OFFLINE:
3649 ret = slab_mem_going_offline_callback(arg);
3650 break;
3651 case MEM_OFFLINE:
3652 case MEM_CANCEL_ONLINE:
3653 slab_mem_offline_callback(arg);
3654 break;
3655 case MEM_ONLINE:
3656 case MEM_CANCEL_OFFLINE:
3657 break;
3658 }
3659 if (ret)
3660 ret = notifier_from_errno(ret);
3661 else
3662 ret = NOTIFY_OK;
3663 return ret;
3664}
3665
3666#endif /* CONFIG_MEMORY_HOTPLUG */
3667
3668/********************************************************************
3669 * Basic setup of slabs
3670 *******************************************************************/
3671
3672/*
3673 * Used for early kmem_cache structures that were allocated using
3674 * the page allocator
3675 */
3676
3677static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s)
3678{
3679 int node;
3680
3681 list_add(&s->list, &slab_caches);
3682 s->refcount = -1;
3683
3684 for_each_node_state(node, N_NORMAL_MEMORY) {
3685 struct kmem_cache_node *n = get_node(s, node);
3686 struct page *p;
3687
3688 if (n) {
3689 list_for_each_entry(p, &n->partial, lru)
3690 p->slab = s;
3691
3692#ifdef CONFIG_SLUB_DEBUG
3693 list_for_each_entry(p, &n->full, lru)
3694 p->slab = s;
3695#endif
3696 }
3697 }
3698}
3699
3700void __init kmem_cache_init(void)
3701{
3702 int i;
3703 int caches = 0;
3704 struct kmem_cache *temp_kmem_cache;
3705 int order;
3706 struct kmem_cache *temp_kmem_cache_node;
3707 unsigned long kmalloc_size;
3708
3709 if (debug_guardpage_minorder())
3710 slub_max_order = 0;
3711
3712 kmem_size = offsetof(struct kmem_cache, node) +
3713 nr_node_ids * sizeof(struct kmem_cache_node *);
3714
3715 /* Allocate two kmem_caches from the page allocator */
3716 kmalloc_size = ALIGN(kmem_size, cache_line_size());
3717 order = get_order(2 * kmalloc_size);
3718 kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
3719
3720 /*
3721 * Must first have the slab cache available for the allocations of the
3722 * struct kmem_cache_node's. There is special bootstrap code in
3723 * kmem_cache_open for slab_state == DOWN.
3724 */
3725 kmem_cache_node = (void *)kmem_cache + kmalloc_size;
3726
3727 kmem_cache_open(kmem_cache_node, "kmem_cache_node",
3728 sizeof(struct kmem_cache_node),
3729 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3730
3731 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3732
3733 /* Able to allocate the per node structures */
3734 slab_state = PARTIAL;
3735
3736 temp_kmem_cache = kmem_cache;
3737 kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
3738 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3739 kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3740 memcpy(kmem_cache, temp_kmem_cache, kmem_size);
3741
3742 /*
3743 * Allocate kmem_cache_node properly from the kmem_cache slab.
3744 * kmem_cache_node is separately allocated so no need to
3745 * update any list pointers.
3746 */
3747 temp_kmem_cache_node = kmem_cache_node;
3748
3749 kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3750 memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
3751
3752 kmem_cache_bootstrap_fixup(kmem_cache_node);
3753
3754 caches++;
3755 kmem_cache_bootstrap_fixup(kmem_cache);
3756 caches++;
3757 /* Free temporary boot structure */
3758 free_pages((unsigned long)temp_kmem_cache, order);
3759
3760 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3761
3762 /*
3763 * Patch up the size_index table if we have strange large alignment
3764 * requirements for the kmalloc array. This is only the case for
3765 * MIPS it seems. The standard arches will not generate any code here.
3766 *
3767 * Largest permitted alignment is 256 bytes due to the way we
3768 * handle the index determination for the smaller caches.
3769 *
3770 * Make sure that nothing crazy happens if someone starts tinkering
3771 * around with ARCH_KMALLOC_MINALIGN
3772 */
3773 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3774 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3775
3776 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
3777 int elem = size_index_elem(i);
3778 if (elem >= ARRAY_SIZE(size_index))
3779 break;
3780 size_index[elem] = KMALLOC_SHIFT_LOW;
3781 }
3782
3783 if (KMALLOC_MIN_SIZE == 64) {
3784 /*
3785 * The 96 byte size cache is not used if the alignment
3786 * is 64 byte.
3787 */
3788 for (i = 64 + 8; i <= 96; i += 8)
3789 size_index[size_index_elem(i)] = 7;
3790 } else if (KMALLOC_MIN_SIZE == 128) {
3791 /*
3792 * The 192 byte sized cache is not used if the alignment
3793 * is 128 byte. Redirect kmalloc to use the 256 byte cache
3794 * instead.
3795 */
3796 for (i = 128 + 8; i <= 192; i += 8)
3797 size_index[size_index_elem(i)] = 8;
3798 }
3799
3800 /* Caches that are not of the two-to-the-power-of size */
3801 if (KMALLOC_MIN_SIZE <= 32) {
3802 kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
3803 caches++;
3804 }
3805
3806 if (KMALLOC_MIN_SIZE <= 64) {
3807 kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
3808 caches++;
3809 }
3810
3811 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3812 kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
3813 caches++;
3814 }
3815
3816 slab_state = UP;
3817
3818 /* Provide the correct kmalloc names now that the caches are up */
3819 if (KMALLOC_MIN_SIZE <= 32) {
3820 kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
3821 BUG_ON(!kmalloc_caches[1]->name);
3822 }
3823
3824 if (KMALLOC_MIN_SIZE <= 64) {
3825 kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
3826 BUG_ON(!kmalloc_caches[2]->name);
3827 }
3828
3829 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3830 char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
3831
3832 BUG_ON(!s);
3833 kmalloc_caches[i]->name = s;
3834 }
3835
3836#ifdef CONFIG_SMP
3837 register_cpu_notifier(&slab_notifier);
3838#endif
3839
3840#ifdef CONFIG_ZONE_DMA
3841 for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
3842 struct kmem_cache *s = kmalloc_caches[i];
3843
3844 if (s && s->size) {
3845 char *name = kasprintf(GFP_NOWAIT,
3846 "dma-kmalloc-%d", s->objsize);
3847
3848 BUG_ON(!name);
3849 kmalloc_dma_caches[i] = create_kmalloc_cache(name,
3850 s->objsize, SLAB_CACHE_DMA);
3851 }
3852 }
3853#endif
3854 printk(KERN_INFO
3855 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3856 " CPUs=%d, Nodes=%d\n",
3857 caches, cache_line_size(),
3858 slub_min_order, slub_max_order, slub_min_objects,
3859 nr_cpu_ids, nr_node_ids);
3860}
3861
3862void __init kmem_cache_init_late(void)
3863{
3864}
3865
3866/*
3867 * Find a mergeable slab cache
3868 */
3869static int slab_unmergeable(struct kmem_cache *s)
3870{
3871 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3872 return 1;
3873
3874 if (s->ctor)
3875 return 1;
3876
3877 /*
3878 * We may have set a slab to be unmergeable during bootstrap.
3879 */
3880 if (s->refcount < 0)
3881 return 1;
3882
3883 return 0;
3884}
3885
3886static struct kmem_cache *find_mergeable(size_t size,
3887 size_t align, unsigned long flags, const char *name,
3888 void (*ctor)(void *))
3889{
3890 struct kmem_cache *s;
3891
3892 if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3893 return NULL;
3894
3895 if (ctor)
3896 return NULL;
3897
3898 size = ALIGN(size, sizeof(void *));
3899 align = calculate_alignment(flags, align, size);
3900 size = ALIGN(size, align);
3901 flags = kmem_cache_flags(size, flags, name, NULL);
3902
3903 list_for_each_entry(s, &slab_caches, list) {
3904 if (slab_unmergeable(s))
3905 continue;
3906
3907 if (size > s->size)
3908 continue;
3909
3910 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3911 continue;
3912 /*
3913 * Check if alignment is compatible.
3914 * Courtesy of Adrian Drzewiecki
3915 */
3916 if ((s->size & ~(align - 1)) != s->size)
3917 continue;
3918
3919 if (s->size - size >= sizeof(void *))
3920 continue;
3921
3922 return s;
3923 }
3924 return NULL;
3925}
3926
3927struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3928 size_t align, unsigned long flags, void (*ctor)(void *))
3929{
3930 struct kmem_cache *s;
3931 char *n;
3932
3933 if (WARN_ON(!name))
3934 return NULL;
3935
3936 down_write(&slub_lock);
3937 s = find_mergeable(size, align, flags, name, ctor);
3938 if (s) {
3939 s->refcount++;
3940 /*
3941 * Adjust the object sizes so that we clear
3942 * the complete object on kzalloc.
3943 */
3944 s->objsize = max(s->objsize, (int)size);
3945 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3946
3947 if (sysfs_slab_alias(s, name)) {
3948 s->refcount--;
3949 goto err;
3950 }
3951 up_write(&slub_lock);
3952 return s;
3953 }
3954
3955 n = kstrdup(name, GFP_KERNEL);
3956 if (!n)
3957 goto err;
3958
3959 s = kmalloc(kmem_size, GFP_KERNEL);
3960 if (s) {
3961 if (kmem_cache_open(s, n,
3962 size, align, flags, ctor)) {
3963 list_add(&s->list, &slab_caches);
3964 up_write(&slub_lock);
3965 if (sysfs_slab_add(s)) {
3966 down_write(&slub_lock);
3967 list_del(&s->list);
3968 kfree(n);
3969 kfree(s);
3970 goto err;
3971 }
3972 return s;
3973 }
3974 kfree(s);
3975 }
3976 kfree(n);
3977err:
3978 up_write(&slub_lock);
3979
3980 if (flags & SLAB_PANIC)
3981 panic("Cannot create slabcache %s\n", name);
3982 else
3983 s = NULL;
3984 return s;
3985}
3986EXPORT_SYMBOL(kmem_cache_create);
3987
3988#ifdef CONFIG_SMP
3989/*
3990 * Use the cpu notifier to insure that the cpu slabs are flushed when
3991 * necessary.
3992 */
3993static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3994 unsigned long action, void *hcpu)
3995{
3996 long cpu = (long)hcpu;
3997 struct kmem_cache *s;
3998 unsigned long flags;
3999
4000 switch (action) {
4001 case CPU_UP_CANCELED:
4002 case CPU_UP_CANCELED_FROZEN:
4003 case CPU_DEAD:
4004 case CPU_DEAD_FROZEN:
4005 down_read(&slub_lock);
4006 list_for_each_entry(s, &slab_caches, list) {
4007 local_irq_save(flags);
4008 __flush_cpu_slab(s, cpu);
4009 local_irq_restore(flags);
4010 }
4011 up_read(&slub_lock);
4012 break;
4013 default:
4014 break;
4015 }
4016 return NOTIFY_OK;
4017}
4018
4019static struct notifier_block __cpuinitdata slab_notifier = {
4020 .notifier_call = slab_cpuup_callback
4021};
4022
4023#endif
4024
4025void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4026{
4027 struct kmem_cache *s;
4028 void *ret;
4029
4030 if (unlikely(size > SLUB_MAX_SIZE))
4031 return kmalloc_large(size, gfpflags);
4032
4033 s = get_slab(size, gfpflags);
4034
4035 if (unlikely(ZERO_OR_NULL_PTR(s)))
4036 return s;
4037
4038 ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, caller);
4039
4040 /* Honor the call site pointer we received. */
4041 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4042
4043 return ret;
4044}
4045
4046#ifdef CONFIG_NUMA
4047void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4048 int node, unsigned long caller)
4049{
4050 struct kmem_cache *s;
4051 void *ret;
4052
4053 if (unlikely(size > SLUB_MAX_SIZE)) {
4054 ret = kmalloc_large_node(size, gfpflags, node);
4055
4056 trace_kmalloc_node(caller, ret,
4057 size, PAGE_SIZE << get_order(size),
4058 gfpflags, node);
4059
4060 return ret;
4061 }
4062
4063 s = get_slab(size, gfpflags);
4064
4065 if (unlikely(ZERO_OR_NULL_PTR(s)))
4066 return s;
4067
4068 ret = slab_alloc(s, gfpflags, node, caller);
4069
4070 /* Honor the call site pointer we received. */
4071 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4072
4073 return ret;
4074}
4075#endif
4076
4077#ifdef CONFIG_SYSFS
4078static int count_inuse(struct page *page)
4079{
4080 return page->inuse;
4081}
4082
4083static int count_total(struct page *page)
4084{
4085 return page->objects;
4086}
4087#endif
4088
4089#ifdef CONFIG_SLUB_DEBUG
4090static int validate_slab(struct kmem_cache *s, struct page *page,
4091 unsigned long *map)
4092{
4093 void *p;
4094 void *addr = page_address(page);
4095
4096 if (!check_slab(s, page) ||
4097 !on_freelist(s, page, NULL))
4098 return 0;
4099
4100 /* Now we know that a valid freelist exists */
4101 bitmap_zero(map, page->objects);
4102
4103 get_map(s, page, map);
4104 for_each_object(p, s, addr, page->objects) {
4105 if (test_bit(slab_index(p, s, addr), map))
4106 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4107 return 0;
4108 }
4109
4110 for_each_object(p, s, addr, page->objects)
4111 if (!test_bit(slab_index(p, s, addr), map))
4112 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4113 return 0;
4114 return 1;
4115}
4116
4117static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4118 unsigned long *map)
4119{
4120 slab_lock(page);
4121 validate_slab(s, page, map);
4122 slab_unlock(page);
4123}
4124
4125static int validate_slab_node(struct kmem_cache *s,
4126 struct kmem_cache_node *n, unsigned long *map)
4127{
4128 unsigned long count = 0;
4129 struct page *page;
4130 unsigned long flags;
4131
4132 spin_lock_irqsave(&n->list_lock, flags);
4133
4134 list_for_each_entry(page, &n->partial, lru) {
4135 validate_slab_slab(s, page, map);
4136 count++;
4137 }
4138 if (count != n->nr_partial)
4139 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
4140 "counter=%ld\n", s->name, count, n->nr_partial);
4141
4142 if (!(s->flags & SLAB_STORE_USER))
4143 goto out;
4144
4145 list_for_each_entry(page, &n->full, lru) {
4146 validate_slab_slab(s, page, map);
4147 count++;
4148 }
4149 if (count != atomic_long_read(&n->nr_slabs))
4150 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
4151 "counter=%ld\n", s->name, count,
4152 atomic_long_read(&n->nr_slabs));
4153
4154out:
4155 spin_unlock_irqrestore(&n->list_lock, flags);
4156 return count;
4157}
4158
4159static long validate_slab_cache(struct kmem_cache *s)
4160{
4161 int node;
4162 unsigned long count = 0;
4163 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4164 sizeof(unsigned long), GFP_KERNEL);
4165
4166 if (!map)
4167 return -ENOMEM;
4168
4169 flush_all(s);
4170 for_each_node_state(node, N_NORMAL_MEMORY) {
4171 struct kmem_cache_node *n = get_node(s, node);
4172
4173 count += validate_slab_node(s, n, map);
4174 }
4175 kfree(map);
4176 return count;
4177}
4178/*
4179 * Generate lists of code addresses where slabcache objects are allocated
4180 * and freed.
4181 */
4182
4183struct location {
4184 unsigned long count;
4185 unsigned long addr;
4186 long long sum_time;
4187 long min_time;
4188 long max_time;
4189 long min_pid;
4190 long max_pid;
4191 DECLARE_BITMAP(cpus, NR_CPUS);
4192 nodemask_t nodes;
4193};
4194
4195struct loc_track {
4196 unsigned long max;
4197 unsigned long count;
4198 struct location *loc;
4199};
4200
4201static void free_loc_track(struct loc_track *t)
4202{
4203 if (t->max)
4204 free_pages((unsigned long)t->loc,
4205 get_order(sizeof(struct location) * t->max));
4206}
4207
4208static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4209{
4210 struct location *l;
4211 int order;
4212
4213 order = get_order(sizeof(struct location) * max);
4214
4215 l = (void *)__get_free_pages(flags, order);
4216 if (!l)
4217 return 0;
4218
4219 if (t->count) {
4220 memcpy(l, t->loc, sizeof(struct location) * t->count);
4221 free_loc_track(t);
4222 }
4223 t->max = max;
4224 t->loc = l;
4225 return 1;
4226}
4227
4228static int add_location(struct loc_track *t, struct kmem_cache *s,
4229 const struct track *track)
4230{
4231 long start, end, pos;
4232 struct location *l;
4233 unsigned long caddr;
4234 unsigned long age = jiffies - track->when;
4235
4236 start = -1;
4237 end = t->count;
4238
4239 for ( ; ; ) {
4240 pos = start + (end - start + 1) / 2;
4241
4242 /*
4243 * There is nothing at "end". If we end up there
4244 * we need to add something to before end.
4245 */
4246 if (pos == end)
4247 break;
4248
4249 caddr = t->loc[pos].addr;
4250 if (track->addr == caddr) {
4251
4252 l = &t->loc[pos];
4253 l->count++;
4254 if (track->when) {
4255 l->sum_time += age;
4256 if (age < l->min_time)
4257 l->min_time = age;
4258 if (age > l->max_time)
4259 l->max_time = age;
4260
4261 if (track->pid < l->min_pid)
4262 l->min_pid = track->pid;
4263 if (track->pid > l->max_pid)
4264 l->max_pid = track->pid;
4265
4266 cpumask_set_cpu(track->cpu,
4267 to_cpumask(l->cpus));
4268 }
4269 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4270 return 1;
4271 }
4272
4273 if (track->addr < caddr)
4274 end = pos;
4275 else
4276 start = pos;
4277 }
4278
4279 /*
4280 * Not found. Insert new tracking element.
4281 */
4282 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4283 return 0;
4284
4285 l = t->loc + pos;
4286 if (pos < t->count)
4287 memmove(l + 1, l,
4288 (t->count - pos) * sizeof(struct location));
4289 t->count++;
4290 l->count = 1;
4291 l->addr = track->addr;
4292 l->sum_time = age;
4293 l->min_time = age;
4294 l->max_time = age;
4295 l->min_pid = track->pid;
4296 l->max_pid = track->pid;
4297 cpumask_clear(to_cpumask(l->cpus));
4298 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4299 nodes_clear(l->nodes);
4300 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4301 return 1;
4302}
4303
4304static void process_slab(struct loc_track *t, struct kmem_cache *s,
4305 struct page *page, enum track_item alloc,
4306 unsigned long *map)
4307{
4308 void *addr = page_address(page);
4309 void *p;
4310
4311 bitmap_zero(map, page->objects);
4312 get_map(s, page, map);
4313
4314 for_each_object(p, s, addr, page->objects)
4315 if (!test_bit(slab_index(p, s, addr), map))
4316 add_location(t, s, get_track(s, p, alloc));
4317}
4318
4319static int list_locations(struct kmem_cache *s, char *buf,
4320 enum track_item alloc)
4321{
4322 int len = 0;
4323 unsigned long i;
4324 struct loc_track t = { 0, 0, NULL };
4325 int node;
4326 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4327 sizeof(unsigned long), GFP_KERNEL);
4328
4329 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4330 GFP_TEMPORARY)) {
4331 kfree(map);
4332 return sprintf(buf, "Out of memory\n");
4333 }
4334 /* Push back cpu slabs */
4335 flush_all(s);
4336
4337 for_each_node_state(node, N_NORMAL_MEMORY) {
4338 struct kmem_cache_node *n = get_node(s, node);
4339 unsigned long flags;
4340 struct page *page;
4341
4342 if (!atomic_long_read(&n->nr_slabs))
4343 continue;
4344
4345 spin_lock_irqsave(&n->list_lock, flags);
4346 list_for_each_entry(page, &n->partial, lru)
4347 process_slab(&t, s, page, alloc, map);
4348 list_for_each_entry(page, &n->full, lru)
4349 process_slab(&t, s, page, alloc, map);
4350 spin_unlock_irqrestore(&n->list_lock, flags);
4351 }
4352
4353 for (i = 0; i < t.count; i++) {
4354 struct location *l = &t.loc[i];
4355
4356 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4357 break;
4358 len += sprintf(buf + len, "%7ld ", l->count);
4359
4360 if (l->addr)
4361 len += sprintf(buf + len, "%pS", (void *)l->addr);
4362 else
4363 len += sprintf(buf + len, "<not-available>");
4364
4365 if (l->sum_time != l->min_time) {
4366 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4367 l->min_time,
4368 (long)div_u64(l->sum_time, l->count),
4369 l->max_time);
4370 } else
4371 len += sprintf(buf + len, " age=%ld",
4372 l->min_time);
4373
4374 if (l->min_pid != l->max_pid)
4375 len += sprintf(buf + len, " pid=%ld-%ld",
4376 l->min_pid, l->max_pid);
4377 else
4378 len += sprintf(buf + len, " pid=%ld",
4379 l->min_pid);
4380
4381 if (num_online_cpus() > 1 &&
4382 !cpumask_empty(to_cpumask(l->cpus)) &&
4383 len < PAGE_SIZE - 60) {
4384 len += sprintf(buf + len, " cpus=");
4385 len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4386 to_cpumask(l->cpus));
4387 }
4388
4389 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4390 len < PAGE_SIZE - 60) {
4391 len += sprintf(buf + len, " nodes=");
4392 len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4393 l->nodes);
4394 }
4395
4396 len += sprintf(buf + len, "\n");
4397 }
4398
4399 free_loc_track(&t);
4400 kfree(map);
4401 if (!t.count)
4402 len += sprintf(buf, "No data\n");
4403 return len;
4404}
4405#endif
4406
4407#ifdef SLUB_RESILIENCY_TEST
4408static void resiliency_test(void)
4409{
4410 u8 *p;
4411
4412 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
4413
4414 printk(KERN_ERR "SLUB resiliency testing\n");
4415 printk(KERN_ERR "-----------------------\n");
4416 printk(KERN_ERR "A. Corruption after allocation\n");
4417
4418 p = kzalloc(16, GFP_KERNEL);
4419 p[16] = 0x12;
4420 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4421 " 0x12->0x%p\n\n", p + 16);
4422
4423 validate_slab_cache(kmalloc_caches[4]);
4424
4425 /* Hmmm... The next two are dangerous */
4426 p = kzalloc(32, GFP_KERNEL);
4427 p[32 + sizeof(void *)] = 0x34;
4428 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4429 " 0x34 -> -0x%p\n", p);
4430 printk(KERN_ERR
4431 "If allocated object is overwritten then not detectable\n\n");
4432
4433 validate_slab_cache(kmalloc_caches[5]);
4434 p = kzalloc(64, GFP_KERNEL);
4435 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4436 *p = 0x56;
4437 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4438 p);
4439 printk(KERN_ERR
4440 "If allocated object is overwritten then not detectable\n\n");
4441 validate_slab_cache(kmalloc_caches[6]);
4442
4443 printk(KERN_ERR "\nB. Corruption after free\n");
4444 p = kzalloc(128, GFP_KERNEL);
4445 kfree(p);
4446 *p = 0x78;
4447 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4448 validate_slab_cache(kmalloc_caches[7]);
4449
4450 p = kzalloc(256, GFP_KERNEL);
4451 kfree(p);
4452 p[50] = 0x9a;
4453 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4454 p);
4455 validate_slab_cache(kmalloc_caches[8]);
4456
4457 p = kzalloc(512, GFP_KERNEL);
4458 kfree(p);
4459 p[512] = 0xab;
4460 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4461 validate_slab_cache(kmalloc_caches[9]);
4462}
4463#else
4464#ifdef CONFIG_SYSFS
4465static void resiliency_test(void) {};
4466#endif
4467#endif
4468
4469#ifdef CONFIG_SYSFS
4470enum slab_stat_type {
4471 SL_ALL, /* All slabs */
4472 SL_PARTIAL, /* Only partially allocated slabs */
4473 SL_CPU, /* Only slabs used for cpu caches */
4474 SL_OBJECTS, /* Determine allocated objects not slabs */
4475 SL_TOTAL /* Determine object capacity not slabs */
4476};
4477
4478#define SO_ALL (1 << SL_ALL)
4479#define SO_PARTIAL (1 << SL_PARTIAL)
4480#define SO_CPU (1 << SL_CPU)
4481#define SO_OBJECTS (1 << SL_OBJECTS)
4482#define SO_TOTAL (1 << SL_TOTAL)
4483
4484static ssize_t show_slab_objects(struct kmem_cache *s,
4485 char *buf, unsigned long flags)
4486{
4487 unsigned long total = 0;
4488 int node;
4489 int x;
4490 unsigned long *nodes;
4491 unsigned long *per_cpu;
4492
4493 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4494 if (!nodes)
4495 return -ENOMEM;
4496 per_cpu = nodes + nr_node_ids;
4497
4498 if (flags & SO_CPU) {
4499 int cpu;
4500
4501 for_each_possible_cpu(cpu) {
4502 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
4503 int node = ACCESS_ONCE(c->node);
4504 struct page *page;
4505
4506 if (node < 0)
4507 continue;
4508 page = ACCESS_ONCE(c->page);
4509 if (page) {
4510 if (flags & SO_TOTAL)
4511 x = page->objects;
4512 else if (flags & SO_OBJECTS)
4513 x = page->inuse;
4514 else
4515 x = 1;
4516
4517 total += x;
4518 nodes[node] += x;
4519 }
4520 page = c->partial;
4521
4522 if (page) {
4523 x = page->pobjects;
4524 total += x;
4525 nodes[node] += x;
4526 }
4527 per_cpu[node]++;
4528 }
4529 }
4530
4531 lock_memory_hotplug();
4532#ifdef CONFIG_SLUB_DEBUG
4533 if (flags & SO_ALL) {
4534 for_each_node_state(node, N_NORMAL_MEMORY) {
4535 struct kmem_cache_node *n = get_node(s, node);
4536
4537 if (flags & SO_TOTAL)
4538 x = atomic_long_read(&n->total_objects);
4539 else if (flags & SO_OBJECTS)
4540 x = atomic_long_read(&n->total_objects) -
4541 count_partial(n, count_free);
4542
4543 else
4544 x = atomic_long_read(&n->nr_slabs);
4545 total += x;
4546 nodes[node] += x;
4547 }
4548
4549 } else
4550#endif
4551 if (flags & SO_PARTIAL) {
4552 for_each_node_state(node, N_NORMAL_MEMORY) {
4553 struct kmem_cache_node *n = get_node(s, node);
4554
4555 if (flags & SO_TOTAL)
4556 x = count_partial(n, count_total);
4557 else if (flags & SO_OBJECTS)
4558 x = count_partial(n, count_inuse);
4559 else
4560 x = n->nr_partial;
4561 total += x;
4562 nodes[node] += x;
4563 }
4564 }
4565 x = sprintf(buf, "%lu", total);
4566#ifdef CONFIG_NUMA
4567 for_each_node_state(node, N_NORMAL_MEMORY)
4568 if (nodes[node])
4569 x += sprintf(buf + x, " N%d=%lu",
4570 node, nodes[node]);
4571#endif
4572 unlock_memory_hotplug();
4573 kfree(nodes);
4574 return x + sprintf(buf + x, "\n");
4575}
4576
4577#ifdef CONFIG_SLUB_DEBUG
4578static int any_slab_objects(struct kmem_cache *s)
4579{
4580 int node;
4581
4582 for_each_online_node(node) {
4583 struct kmem_cache_node *n = get_node(s, node);
4584
4585 if (!n)
4586 continue;
4587
4588 if (atomic_long_read(&n->total_objects))
4589 return 1;
4590 }
4591 return 0;
4592}
4593#endif
4594
4595#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4596#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4597
4598struct slab_attribute {
4599 struct attribute attr;
4600 ssize_t (*show)(struct kmem_cache *s, char *buf);
4601 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4602};
4603
4604#define SLAB_ATTR_RO(_name) \
4605 static struct slab_attribute _name##_attr = \
4606 __ATTR(_name, 0400, _name##_show, NULL)
4607
4608#define SLAB_ATTR(_name) \
4609 static struct slab_attribute _name##_attr = \
4610 __ATTR(_name, 0600, _name##_show, _name##_store)
4611
4612static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4613{
4614 return sprintf(buf, "%d\n", s->size);
4615}
4616SLAB_ATTR_RO(slab_size);
4617
4618static ssize_t align_show(struct kmem_cache *s, char *buf)
4619{
4620 return sprintf(buf, "%d\n", s->align);
4621}
4622SLAB_ATTR_RO(align);
4623
4624static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4625{
4626 return sprintf(buf, "%d\n", s->objsize);
4627}
4628SLAB_ATTR_RO(object_size);
4629
4630static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4631{
4632 return sprintf(buf, "%d\n", oo_objects(s->oo));
4633}
4634SLAB_ATTR_RO(objs_per_slab);
4635
4636static ssize_t order_store(struct kmem_cache *s,
4637 const char *buf, size_t length)
4638{
4639 unsigned long order;
4640 int err;
4641
4642 err = strict_strtoul(buf, 10, &order);
4643 if (err)
4644 return err;
4645
4646 if (order > slub_max_order || order < slub_min_order)
4647 return -EINVAL;
4648
4649 calculate_sizes(s, order);
4650 return length;
4651}
4652
4653static ssize_t order_show(struct kmem_cache *s, char *buf)
4654{
4655 return sprintf(buf, "%d\n", oo_order(s->oo));
4656}
4657SLAB_ATTR(order);
4658
4659static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4660{
4661 return sprintf(buf, "%lu\n", s->min_partial);
4662}
4663
4664static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4665 size_t length)
4666{
4667 unsigned long min;
4668 int err;
4669
4670 err = strict_strtoul(buf, 10, &min);
4671 if (err)
4672 return err;
4673
4674 set_min_partial(s, min);
4675 return length;
4676}
4677SLAB_ATTR(min_partial);
4678
4679static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4680{
4681 return sprintf(buf, "%u\n", s->cpu_partial);
4682}
4683
4684static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4685 size_t length)
4686{
4687 unsigned long objects;
4688 int err;
4689
4690 err = strict_strtoul(buf, 10, &objects);
4691 if (err)
4692 return err;
4693 if (objects && kmem_cache_debug(s))
4694 return -EINVAL;
4695
4696 s->cpu_partial = objects;
4697 flush_all(s);
4698 return length;
4699}
4700SLAB_ATTR(cpu_partial);
4701
4702static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4703{
4704 if (!s->ctor)
4705 return 0;
4706 return sprintf(buf, "%pS\n", s->ctor);
4707}
4708SLAB_ATTR_RO(ctor);
4709
4710static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4711{
4712 return sprintf(buf, "%d\n", s->refcount - 1);
4713}
4714SLAB_ATTR_RO(aliases);
4715
4716static ssize_t partial_show(struct kmem_cache *s, char *buf)
4717{
4718 return show_slab_objects(s, buf, SO_PARTIAL);
4719}
4720SLAB_ATTR_RO(partial);
4721
4722static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4723{
4724 return show_slab_objects(s, buf, SO_CPU);
4725}
4726SLAB_ATTR_RO(cpu_slabs);
4727
4728static ssize_t objects_show(struct kmem_cache *s, char *buf)
4729{
4730 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4731}
4732SLAB_ATTR_RO(objects);
4733
4734static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4735{
4736 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4737}
4738SLAB_ATTR_RO(objects_partial);
4739
4740static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4741{
4742 int objects = 0;
4743 int pages = 0;
4744 int cpu;
4745 int len;
4746
4747 for_each_online_cpu(cpu) {
4748 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4749
4750 if (page) {
4751 pages += page->pages;
4752 objects += page->pobjects;
4753 }
4754 }
4755
4756 len = sprintf(buf, "%d(%d)", objects, pages);
4757
4758#ifdef CONFIG_SMP
4759 for_each_online_cpu(cpu) {
4760 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4761
4762 if (page && len < PAGE_SIZE - 20)
4763 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4764 page->pobjects, page->pages);
4765 }
4766#endif
4767 return len + sprintf(buf + len, "\n");
4768}
4769SLAB_ATTR_RO(slabs_cpu_partial);
4770
4771static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4772{
4773 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4774}
4775
4776static ssize_t reclaim_account_store(struct kmem_cache *s,
4777 const char *buf, size_t length)
4778{
4779 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4780 if (buf[0] == '1')
4781 s->flags |= SLAB_RECLAIM_ACCOUNT;
4782 return length;
4783}
4784SLAB_ATTR(reclaim_account);
4785
4786static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4787{
4788 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4789}
4790SLAB_ATTR_RO(hwcache_align);
4791
4792#ifdef CONFIG_ZONE_DMA
4793static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4794{
4795 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4796}
4797SLAB_ATTR_RO(cache_dma);
4798#endif
4799
4800static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4801{
4802 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4803}
4804SLAB_ATTR_RO(destroy_by_rcu);
4805
4806static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4807{
4808 return sprintf(buf, "%d\n", s->reserved);
4809}
4810SLAB_ATTR_RO(reserved);
4811
4812#ifdef CONFIG_SLUB_DEBUG
4813static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4814{
4815 return show_slab_objects(s, buf, SO_ALL);
4816}
4817SLAB_ATTR_RO(slabs);
4818
4819static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4820{
4821 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4822}
4823SLAB_ATTR_RO(total_objects);
4824
4825static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4826{
4827 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4828}
4829
4830static ssize_t sanity_checks_store(struct kmem_cache *s,
4831 const char *buf, size_t length)
4832{
4833 s->flags &= ~SLAB_DEBUG_FREE;
4834 if (buf[0] == '1') {
4835 s->flags &= ~__CMPXCHG_DOUBLE;
4836 s->flags |= SLAB_DEBUG_FREE;
4837 }
4838 return length;
4839}
4840SLAB_ATTR(sanity_checks);
4841
4842static ssize_t trace_show(struct kmem_cache *s, char *buf)
4843{
4844 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4845}
4846
4847static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4848 size_t length)
4849{
4850 s->flags &= ~SLAB_TRACE;
4851 if (buf[0] == '1') {
4852 s->flags &= ~__CMPXCHG_DOUBLE;
4853 s->flags |= SLAB_TRACE;
4854 }
4855 return length;
4856}
4857SLAB_ATTR(trace);
4858
4859static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4860{
4861 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4862}
4863
4864static ssize_t red_zone_store(struct kmem_cache *s,
4865 const char *buf, size_t length)
4866{
4867 if (any_slab_objects(s))
4868 return -EBUSY;
4869
4870 s->flags &= ~SLAB_RED_ZONE;
4871 if (buf[0] == '1') {
4872 s->flags &= ~__CMPXCHG_DOUBLE;
4873 s->flags |= SLAB_RED_ZONE;
4874 }
4875 calculate_sizes(s, -1);
4876 return length;
4877}
4878SLAB_ATTR(red_zone);
4879
4880static ssize_t poison_show(struct kmem_cache *s, char *buf)
4881{
4882 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4883}
4884
4885static ssize_t poison_store(struct kmem_cache *s,
4886 const char *buf, size_t length)
4887{
4888 if (any_slab_objects(s))
4889 return -EBUSY;
4890
4891 s->flags &= ~SLAB_POISON;
4892 if (buf[0] == '1') {
4893 s->flags &= ~__CMPXCHG_DOUBLE;
4894 s->flags |= SLAB_POISON;
4895 }
4896 calculate_sizes(s, -1);
4897 return length;
4898}
4899SLAB_ATTR(poison);
4900
4901static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4902{
4903 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4904}
4905
4906static ssize_t store_user_store(struct kmem_cache *s,
4907 const char *buf, size_t length)
4908{
4909 if (any_slab_objects(s))
4910 return -EBUSY;
4911
4912 s->flags &= ~SLAB_STORE_USER;
4913 if (buf[0] == '1') {
4914 s->flags &= ~__CMPXCHG_DOUBLE;
4915 s->flags |= SLAB_STORE_USER;
4916 }
4917 calculate_sizes(s, -1);
4918 return length;
4919}
4920SLAB_ATTR(store_user);
4921
4922static ssize_t validate_show(struct kmem_cache *s, char *buf)
4923{
4924 return 0;
4925}
4926
4927static ssize_t validate_store(struct kmem_cache *s,
4928 const char *buf, size_t length)
4929{
4930 int ret = -EINVAL;
4931
4932 if (buf[0] == '1') {
4933 ret = validate_slab_cache(s);
4934 if (ret >= 0)
4935 ret = length;
4936 }
4937 return ret;
4938}
4939SLAB_ATTR(validate);
4940
4941static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4942{
4943 if (!(s->flags & SLAB_STORE_USER))
4944 return -ENOSYS;
4945 return list_locations(s, buf, TRACK_ALLOC);
4946}
4947SLAB_ATTR_RO(alloc_calls);
4948
4949static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4950{
4951 if (!(s->flags & SLAB_STORE_USER))
4952 return -ENOSYS;
4953 return list_locations(s, buf, TRACK_FREE);
4954}
4955SLAB_ATTR_RO(free_calls);
4956#endif /* CONFIG_SLUB_DEBUG */
4957
4958#ifdef CONFIG_FAILSLAB
4959static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4960{
4961 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4962}
4963
4964static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4965 size_t length)
4966{
4967 s->flags &= ~SLAB_FAILSLAB;
4968 if (buf[0] == '1')
4969 s->flags |= SLAB_FAILSLAB;
4970 return length;
4971}
4972SLAB_ATTR(failslab);
4973#endif
4974
4975static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4976{
4977 return 0;
4978}
4979
4980static ssize_t shrink_store(struct kmem_cache *s,
4981 const char *buf, size_t length)
4982{
4983 if (buf[0] == '1') {
4984 int rc = kmem_cache_shrink(s);
4985
4986 if (rc)
4987 return rc;
4988 } else
4989 return -EINVAL;
4990 return length;
4991}
4992SLAB_ATTR(shrink);
4993
4994#ifdef CONFIG_NUMA
4995static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4996{
4997 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4998}
4999
5000static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5001 const char *buf, size_t length)
5002{
5003 unsigned long ratio;
5004 int err;
5005
5006 err = strict_strtoul(buf, 10, &ratio);
5007 if (err)
5008 return err;
5009
5010 if (ratio <= 100)
5011 s->remote_node_defrag_ratio = ratio * 10;
5012
5013 return length;
5014}
5015SLAB_ATTR(remote_node_defrag_ratio);
5016#endif
5017
5018#ifdef CONFIG_SLUB_STATS
5019static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5020{
5021 unsigned long sum = 0;
5022 int cpu;
5023 int len;
5024 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5025
5026 if (!data)
5027 return -ENOMEM;
5028
5029 for_each_online_cpu(cpu) {
5030 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5031
5032 data[cpu] = x;
5033 sum += x;
5034 }
5035
5036 len = sprintf(buf, "%lu", sum);
5037
5038#ifdef CONFIG_SMP
5039 for_each_online_cpu(cpu) {
5040 if (data[cpu] && len < PAGE_SIZE - 20)
5041 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5042 }
5043#endif
5044 kfree(data);
5045 return len + sprintf(buf + len, "\n");
5046}
5047
5048static void clear_stat(struct kmem_cache *s, enum stat_item si)
5049{
5050 int cpu;
5051
5052 for_each_online_cpu(cpu)
5053 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5054}
5055
5056#define STAT_ATTR(si, text) \
5057static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5058{ \
5059 return show_stat(s, buf, si); \
5060} \
5061static ssize_t text##_store(struct kmem_cache *s, \
5062 const char *buf, size_t length) \
5063{ \
5064 if (buf[0] != '0') \
5065 return -EINVAL; \
5066 clear_stat(s, si); \
5067 return length; \
5068} \
5069SLAB_ATTR(text); \
5070
5071STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5072STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5073STAT_ATTR(FREE_FASTPATH, free_fastpath);
5074STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5075STAT_ATTR(FREE_FROZEN, free_frozen);
5076STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5077STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5078STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5079STAT_ATTR(ALLOC_SLAB, alloc_slab);
5080STAT_ATTR(ALLOC_REFILL, alloc_refill);
5081STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5082STAT_ATTR(FREE_SLAB, free_slab);
5083STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5084STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5085STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5086STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5087STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5088STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5089STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5090STAT_ATTR(ORDER_FALLBACK, order_fallback);
5091STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5092STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5093STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5094STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5095STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5096STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5097#endif
5098
5099static struct attribute *slab_attrs[] = {
5100 &slab_size_attr.attr,
5101 &object_size_attr.attr,
5102 &objs_per_slab_attr.attr,
5103 &order_attr.attr,
5104 &min_partial_attr.attr,
5105 &cpu_partial_attr.attr,
5106 &objects_attr.attr,
5107 &objects_partial_attr.attr,
5108 &partial_attr.attr,
5109 &cpu_slabs_attr.attr,
5110 &ctor_attr.attr,
5111 &aliases_attr.attr,
5112 &align_attr.attr,
5113 &hwcache_align_attr.attr,
5114 &reclaim_account_attr.attr,
5115 &destroy_by_rcu_attr.attr,
5116 &shrink_attr.attr,
5117 &reserved_attr.attr,
5118 &slabs_cpu_partial_attr.attr,
5119#ifdef CONFIG_SLUB_DEBUG
5120 &total_objects_attr.attr,
5121 &slabs_attr.attr,
5122 &sanity_checks_attr.attr,
5123 &trace_attr.attr,
5124 &red_zone_attr.attr,
5125 &poison_attr.attr,
5126 &store_user_attr.attr,
5127 &validate_attr.attr,
5128 &alloc_calls_attr.attr,
5129 &free_calls_attr.attr,
5130#endif
5131#ifdef CONFIG_ZONE_DMA
5132 &cache_dma_attr.attr,
5133#endif
5134#ifdef CONFIG_NUMA
5135 &remote_node_defrag_ratio_attr.attr,
5136#endif
5137#ifdef CONFIG_SLUB_STATS
5138 &alloc_fastpath_attr.attr,
5139 &alloc_slowpath_attr.attr,
5140 &free_fastpath_attr.attr,
5141 &free_slowpath_attr.attr,
5142 &free_frozen_attr.attr,
5143 &free_add_partial_attr.attr,
5144 &free_remove_partial_attr.attr,
5145 &alloc_from_partial_attr.attr,
5146 &alloc_slab_attr.attr,
5147 &alloc_refill_attr.attr,
5148 &alloc_node_mismatch_attr.attr,
5149 &free_slab_attr.attr,
5150 &cpuslab_flush_attr.attr,
5151 &deactivate_full_attr.attr,
5152 &deactivate_empty_attr.attr,
5153 &deactivate_to_head_attr.attr,
5154 &deactivate_to_tail_attr.attr,
5155 &deactivate_remote_frees_attr.attr,
5156 &deactivate_bypass_attr.attr,
5157 &order_fallback_attr.attr,
5158 &cmpxchg_double_fail_attr.attr,
5159 &cmpxchg_double_cpu_fail_attr.attr,
5160 &cpu_partial_alloc_attr.attr,
5161 &cpu_partial_free_attr.attr,
5162 &cpu_partial_node_attr.attr,
5163 &cpu_partial_drain_attr.attr,
5164#endif
5165#ifdef CONFIG_FAILSLAB
5166 &failslab_attr.attr,
5167#endif
5168
5169 NULL
5170};
5171
5172static struct attribute_group slab_attr_group = {
5173 .attrs = slab_attrs,
5174};
5175
5176static ssize_t slab_attr_show(struct kobject *kobj,
5177 struct attribute *attr,
5178 char *buf)
5179{
5180 struct slab_attribute *attribute;
5181 struct kmem_cache *s;
5182 int err;
5183
5184 attribute = to_slab_attr(attr);
5185 s = to_slab(kobj);
5186
5187 if (!attribute->show)
5188 return -EIO;
5189
5190 err = attribute->show(s, buf);
5191
5192 return err;
5193}
5194
5195static ssize_t slab_attr_store(struct kobject *kobj,
5196 struct attribute *attr,
5197 const char *buf, size_t len)
5198{
5199 struct slab_attribute *attribute;
5200 struct kmem_cache *s;
5201 int err;
5202
5203 attribute = to_slab_attr(attr);
5204 s = to_slab(kobj);
5205
5206 if (!attribute->store)
5207 return -EIO;
5208
5209 err = attribute->store(s, buf, len);
5210
5211 return err;
5212}
5213
5214static void kmem_cache_release(struct kobject *kobj)
5215{
5216 struct kmem_cache *s = to_slab(kobj);
5217
5218 kfree(s->name);
5219 kfree(s);
5220}
5221
5222static const struct sysfs_ops slab_sysfs_ops = {
5223 .show = slab_attr_show,
5224 .store = slab_attr_store,
5225};
5226
5227static struct kobj_type slab_ktype = {
5228 .sysfs_ops = &slab_sysfs_ops,
5229 .release = kmem_cache_release
5230};
5231
5232static int uevent_filter(struct kset *kset, struct kobject *kobj)
5233{
5234 struct kobj_type *ktype = get_ktype(kobj);
5235
5236 if (ktype == &slab_ktype)
5237 return 1;
5238 return 0;
5239}
5240
5241static const struct kset_uevent_ops slab_uevent_ops = {
5242 .filter = uevent_filter,
5243};
5244
5245static struct kset *slab_kset;
5246
5247#define ID_STR_LENGTH 64
5248
5249/* Create a unique string id for a slab cache:
5250 *
5251 * Format :[flags-]size
5252 */
5253static char *create_unique_id(struct kmem_cache *s)
5254{
5255 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5256 char *p = name;
5257
5258 BUG_ON(!name);
5259
5260 *p++ = ':';
5261 /*
5262 * First flags affecting slabcache operations. We will only
5263 * get here for aliasable slabs so we do not need to support
5264 * too many flags. The flags here must cover all flags that
5265 * are matched during merging to guarantee that the id is
5266 * unique.
5267 */
5268 if (s->flags & SLAB_CACHE_DMA)
5269 *p++ = 'd';
5270 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5271 *p++ = 'a';
5272 if (s->flags & SLAB_DEBUG_FREE)
5273 *p++ = 'F';
5274 if (!(s->flags & SLAB_NOTRACK))
5275 *p++ = 't';
5276 if (p != name + 1)
5277 *p++ = '-';
5278 p += sprintf(p, "%07d", s->size);
5279 BUG_ON(p > name + ID_STR_LENGTH - 1);
5280 return name;
5281}
5282
5283static int sysfs_slab_add(struct kmem_cache *s)
5284{
5285 int err;
5286 const char *name;
5287 int unmergeable;
5288
5289 if (slab_state < SYSFS)
5290 /* Defer until later */
5291 return 0;
5292
5293 unmergeable = slab_unmergeable(s);
5294 if (unmergeable) {
5295 /*
5296 * Slabcache can never be merged so we can use the name proper.
5297 * This is typically the case for debug situations. In that
5298 * case we can catch duplicate names easily.
5299 */
5300 sysfs_remove_link(&slab_kset->kobj, s->name);
5301 name = s->name;
5302 } else {
5303 /*
5304 * Create a unique name for the slab as a target
5305 * for the symlinks.
5306 */
5307 name = create_unique_id(s);
5308 }
5309
5310 s->kobj.kset = slab_kset;
5311 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5312 if (err) {
5313 kobject_put(&s->kobj);
5314 return err;
5315 }
5316
5317 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5318 if (err) {
5319 kobject_del(&s->kobj);
5320 kobject_put(&s->kobj);
5321 return err;
5322 }
5323 kobject_uevent(&s->kobj, KOBJ_ADD);
5324 if (!unmergeable) {
5325 /* Setup first alias */
5326 sysfs_slab_alias(s, s->name);
5327 kfree(name);
5328 }
5329 return 0;
5330}
5331
5332static void sysfs_slab_remove(struct kmem_cache *s)
5333{
5334 if (slab_state < SYSFS)
5335 /*
5336 * Sysfs has not been setup yet so no need to remove the
5337 * cache from sysfs.
5338 */
5339 return;
5340
5341 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5342 kobject_del(&s->kobj);
5343 kobject_put(&s->kobj);
5344}
5345
5346/*
5347 * Need to buffer aliases during bootup until sysfs becomes
5348 * available lest we lose that information.
5349 */
5350struct saved_alias {
5351 struct kmem_cache *s;
5352 const char *name;
5353 struct saved_alias *next;
5354};
5355
5356static struct saved_alias *alias_list;
5357
5358static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5359{
5360 struct saved_alias *al;
5361
5362 if (slab_state == SYSFS) {
5363 /*
5364 * If we have a leftover link then remove it.
5365 */
5366 sysfs_remove_link(&slab_kset->kobj, name);
5367 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5368 }
5369
5370 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5371 if (!al)
5372 return -ENOMEM;
5373
5374 al->s = s;
5375 al->name = name;
5376 al->next = alias_list;
5377 alias_list = al;
5378 return 0;
5379}
5380
5381static int __init slab_sysfs_init(void)
5382{
5383 struct kmem_cache *s;
5384 int err;
5385
5386 down_write(&slub_lock);
5387
5388 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5389 if (!slab_kset) {
5390 up_write(&slub_lock);
5391 printk(KERN_ERR "Cannot register slab subsystem.\n");
5392 return -ENOSYS;
5393 }
5394
5395 slab_state = SYSFS;
5396
5397 list_for_each_entry(s, &slab_caches, list) {
5398 err = sysfs_slab_add(s);
5399 if (err)
5400 printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5401 " to sysfs\n", s->name);
5402 }
5403
5404 while (alias_list) {
5405 struct saved_alias *al = alias_list;
5406
5407 alias_list = alias_list->next;
5408 err = sysfs_slab_alias(al->s, al->name);
5409 if (err)
5410 printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5411 " %s to sysfs\n", s->name);
5412 kfree(al);
5413 }
5414
5415 up_write(&slub_lock);
5416 resiliency_test();
5417 return 0;
5418}
5419
5420__initcall(slab_sysfs_init);
5421#endif /* CONFIG_SYSFS */
5422
5423/*
5424 * The /proc/slabinfo ABI
5425 */
5426#ifdef CONFIG_SLABINFO
5427static void print_slabinfo_header(struct seq_file *m)
5428{
5429 seq_puts(m, "slabinfo - version: 2.1\n");
5430 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
5431 "<objperslab> <pagesperslab>");
5432 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
5433 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
5434 seq_putc(m, '\n');
5435}
5436
5437static void *s_start(struct seq_file *m, loff_t *pos)
5438{
5439 loff_t n = *pos;
5440
5441 down_read(&slub_lock);
5442 if (!n)
5443 print_slabinfo_header(m);
5444
5445 return seq_list_start(&slab_caches, *pos);
5446}
5447
5448static void *s_next(struct seq_file *m, void *p, loff_t *pos)
5449{
5450 return seq_list_next(p, &slab_caches, pos);
5451}
5452
5453static void s_stop(struct seq_file *m, void *p)
5454{
5455 up_read(&slub_lock);
5456}
5457
5458static int s_show(struct seq_file *m, void *p)
5459{
5460 unsigned long nr_partials = 0;
5461 unsigned long nr_slabs = 0;
5462 unsigned long nr_inuse = 0;
5463 unsigned long nr_objs = 0;
5464 unsigned long nr_free = 0;
5465 struct kmem_cache *s;
5466 int node;
5467
5468 s = list_entry(p, struct kmem_cache, list);
5469
5470 for_each_online_node(node) {
5471 struct kmem_cache_node *n = get_node(s, node);
5472
5473 if (!n)
5474 continue;
5475
5476 nr_partials += n->nr_partial;
5477 nr_slabs += atomic_long_read(&n->nr_slabs);
5478 nr_objs += atomic_long_read(&n->total_objects);
5479 nr_free += count_partial(n, count_free);
5480 }
5481
5482 nr_inuse = nr_objs - nr_free;
5483
5484 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
5485 nr_objs, s->size, oo_objects(s->oo),
5486 (1 << oo_order(s->oo)));
5487 seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
5488 seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
5489 0UL);
5490 seq_putc(m, '\n');
5491 return 0;
5492}
5493
5494static const struct seq_operations slabinfo_op = {
5495 .start = s_start,
5496 .next = s_next,
5497 .stop = s_stop,
5498 .show = s_show,
5499};
5500
5501static int slabinfo_open(struct inode *inode, struct file *file)
5502{
5503 return seq_open(file, &slabinfo_op);
5504}
5505
5506static const struct file_operations proc_slabinfo_operations = {
5507 .open = slabinfo_open,
5508 .read = seq_read,
5509 .llseek = seq_lseek,
5510 .release = seq_release,
5511};
5512
5513static int __init slab_proc_init(void)
5514{
5515 proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
5516 return 0;
5517}
5518module_init(slab_proc_init);
5519#endif /* CONFIG_SLABINFO */