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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
118 static 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
127 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
135 static 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 /*
198 * Tracking user of a slab.
199 */
200 #define TRACK_ADDRS_COUNT 16
201 struct track {
202 unsigned long addr; /* Called from address */
203 #ifdef CONFIG_STACKTRACE
204 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
205 #endif
206 int cpu; /* Was running on cpu */
207 int pid; /* Pid context */
208 unsigned long when; /* When did the operation occur */
209 };
210
211 enum track_item { TRACK_ALLOC, TRACK_FREE };
212
213 #ifdef CONFIG_SYSFS
214 static int sysfs_slab_add(struct kmem_cache *);
215 static int sysfs_slab_alias(struct kmem_cache *, const char *);
216 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
217 #else
218 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
219 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
220 { return 0; }
221 static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
222 #endif
223
224 static inline void stat(const struct kmem_cache *s, enum stat_item si)
225 {
226 #ifdef CONFIG_SLUB_STATS
227 /*
228 * The rmw is racy on a preemptible kernel but this is acceptable, so
229 * avoid this_cpu_add()'s irq-disable overhead.
230 */
231 raw_cpu_inc(s->cpu_slab->stat[si]);
232 #endif
233 }
234
235 /********************************************************************
236 * Core slab cache functions
237 *******************************************************************/
238
239 static inline void *get_freepointer(struct kmem_cache *s, void *object)
240 {
241 return *(void **)(object + s->offset);
242 }
243
244 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
245 {
246 prefetch(object + s->offset);
247 }
248
249 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
250 {
251 void *p;
252
253 if (!debug_pagealloc_enabled())
254 return get_freepointer(s, object);
255
256 probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
257 return p;
258 }
259
260 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
261 {
262 *(void **)(object + s->offset) = fp;
263 }
264
265 /* Loop over all objects in a slab */
266 #define for_each_object(__p, __s, __addr, __objects) \
267 for (__p = fixup_red_left(__s, __addr); \
268 __p < (__addr) + (__objects) * (__s)->size; \
269 __p += (__s)->size)
270
271 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
272 for (__p = fixup_red_left(__s, __addr), __idx = 1; \
273 __idx <= __objects; \
274 __p += (__s)->size, __idx++)
275
276 /* Determine object index from a given position */
277 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
278 {
279 return (p - addr) / s->size;
280 }
281
282 static inline int order_objects(int order, unsigned long size, int reserved)
283 {
284 return ((PAGE_SIZE << order) - reserved) / size;
285 }
286
287 static inline struct kmem_cache_order_objects oo_make(int order,
288 unsigned long size, int reserved)
289 {
290 struct kmem_cache_order_objects x = {
291 (order << OO_SHIFT) + order_objects(order, size, reserved)
292 };
293
294 return x;
295 }
296
297 static inline int oo_order(struct kmem_cache_order_objects x)
298 {
299 return x.x >> OO_SHIFT;
300 }
301
302 static inline int oo_objects(struct kmem_cache_order_objects x)
303 {
304 return x.x & OO_MASK;
305 }
306
307 /*
308 * Per slab locking using the pagelock
309 */
310 static __always_inline void slab_lock(struct page *page)
311 {
312 VM_BUG_ON_PAGE(PageTail(page), page);
313 bit_spin_lock(PG_locked, &page->flags);
314 }
315
316 static __always_inline void slab_unlock(struct page *page)
317 {
318 VM_BUG_ON_PAGE(PageTail(page), page);
319 __bit_spin_unlock(PG_locked, &page->flags);
320 }
321
322 static inline void set_page_slub_counters(struct page *page, unsigned long counters_new)
323 {
324 struct page tmp;
325 tmp.counters = counters_new;
326 /*
327 * page->counters can cover frozen/inuse/objects as well
328 * as page->_refcount. If we assign to ->counters directly
329 * we run the risk of losing updates to page->_refcount, so
330 * be careful and only assign to the fields we need.
331 */
332 page->frozen = tmp.frozen;
333 page->inuse = tmp.inuse;
334 page->objects = tmp.objects;
335 }
336
337 /* Interrupts must be disabled (for the fallback code to work right) */
338 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
339 void *freelist_old, unsigned long counters_old,
340 void *freelist_new, unsigned long counters_new,
341 const char *n)
342 {
343 VM_BUG_ON(!irqs_disabled());
344 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
345 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
346 if (s->flags & __CMPXCHG_DOUBLE) {
347 if (cmpxchg_double(&page->freelist, &page->counters,
348 freelist_old, counters_old,
349 freelist_new, counters_new))
350 return true;
351 } else
352 #endif
353 {
354 slab_lock(page);
355 if (page->freelist == freelist_old &&
356 page->counters == counters_old) {
357 page->freelist = freelist_new;
358 set_page_slub_counters(page, counters_new);
359 slab_unlock(page);
360 return true;
361 }
362 slab_unlock(page);
363 }
364
365 cpu_relax();
366 stat(s, CMPXCHG_DOUBLE_FAIL);
367
368 #ifdef SLUB_DEBUG_CMPXCHG
369 pr_info("%s %s: cmpxchg double redo ", n, s->name);
370 #endif
371
372 return false;
373 }
374
375 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
376 void *freelist_old, unsigned long counters_old,
377 void *freelist_new, unsigned long counters_new,
378 const char *n)
379 {
380 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
381 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
382 if (s->flags & __CMPXCHG_DOUBLE) {
383 if (cmpxchg_double(&page->freelist, &page->counters,
384 freelist_old, counters_old,
385 freelist_new, counters_new))
386 return true;
387 } else
388 #endif
389 {
390 unsigned long flags;
391
392 local_irq_save(flags);
393 slab_lock(page);
394 if (page->freelist == freelist_old &&
395 page->counters == counters_old) {
396 page->freelist = freelist_new;
397 set_page_slub_counters(page, counters_new);
398 slab_unlock(page);
399 local_irq_restore(flags);
400 return true;
401 }
402 slab_unlock(page);
403 local_irq_restore(flags);
404 }
405
406 cpu_relax();
407 stat(s, CMPXCHG_DOUBLE_FAIL);
408
409 #ifdef SLUB_DEBUG_CMPXCHG
410 pr_info("%s %s: cmpxchg double redo ", n, s->name);
411 #endif
412
413 return false;
414 }
415
416 #ifdef CONFIG_SLUB_DEBUG
417 /*
418 * Determine a map of object in use on a page.
419 *
420 * Node listlock must be held to guarantee that the page does
421 * not vanish from under us.
422 */
423 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
424 {
425 void *p;
426 void *addr = page_address(page);
427
428 for (p = page->freelist; p; p = get_freepointer(s, p))
429 set_bit(slab_index(p, s, addr), map);
430 }
431
432 static inline int size_from_object(struct kmem_cache *s)
433 {
434 if (s->flags & SLAB_RED_ZONE)
435 return s->size - s->red_left_pad;
436
437 return s->size;
438 }
439
440 static inline void *restore_red_left(struct kmem_cache *s, void *p)
441 {
442 if (s->flags & SLAB_RED_ZONE)
443 p -= s->red_left_pad;
444
445 return p;
446 }
447
448 /*
449 * Debug settings:
450 */
451 #if defined(CONFIG_SLUB_DEBUG_ON)
452 static int slub_debug = DEBUG_DEFAULT_FLAGS;
453 #else
454 static int slub_debug;
455 #endif
456
457 static char *slub_debug_slabs;
458 static int disable_higher_order_debug;
459
460 /*
461 * slub is about to manipulate internal object metadata. This memory lies
462 * outside the range of the allocated object, so accessing it would normally
463 * be reported by kasan as a bounds error. metadata_access_enable() is used
464 * to tell kasan that these accesses are OK.
465 */
466 static inline void metadata_access_enable(void)
467 {
468 kasan_disable_current();
469 }
470
471 static inline void metadata_access_disable(void)
472 {
473 kasan_enable_current();
474 }
475
476 /*
477 * Object debugging
478 */
479
480 /* Verify that a pointer has an address that is valid within a slab page */
481 static inline int check_valid_pointer(struct kmem_cache *s,
482 struct page *page, void *object)
483 {
484 void *base;
485
486 if (!object)
487 return 1;
488
489 base = page_address(page);
490 object = restore_red_left(s, object);
491 if (object < base || object >= base + page->objects * s->size ||
492 (object - base) % s->size) {
493 return 0;
494 }
495
496 return 1;
497 }
498
499 static void print_section(char *level, char *text, u8 *addr,
500 unsigned int length)
501 {
502 metadata_access_enable();
503 print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
504 length, 1);
505 metadata_access_disable();
506 }
507
508 static struct track *get_track(struct kmem_cache *s, void *object,
509 enum track_item alloc)
510 {
511 struct track *p;
512
513 if (s->offset)
514 p = object + s->offset + sizeof(void *);
515 else
516 p = object + s->inuse;
517
518 return p + alloc;
519 }
520
521 static void set_track(struct kmem_cache *s, void *object,
522 enum track_item alloc, unsigned long addr)
523 {
524 struct track *p = get_track(s, object, alloc);
525
526 if (addr) {
527 #ifdef CONFIG_STACKTRACE
528 struct stack_trace trace;
529 int i;
530
531 trace.nr_entries = 0;
532 trace.max_entries = TRACK_ADDRS_COUNT;
533 trace.entries = p->addrs;
534 trace.skip = 3;
535 metadata_access_enable();
536 save_stack_trace(&trace);
537 metadata_access_disable();
538
539 /* See rant in lockdep.c */
540 if (trace.nr_entries != 0 &&
541 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
542 trace.nr_entries--;
543
544 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
545 p->addrs[i] = 0;
546 #endif
547 p->addr = addr;
548 p->cpu = smp_processor_id();
549 p->pid = current->pid;
550 p->when = jiffies;
551 } else
552 memset(p, 0, sizeof(struct track));
553 }
554
555 static void init_tracking(struct kmem_cache *s, void *object)
556 {
557 if (!(s->flags & SLAB_STORE_USER))
558 return;
559
560 set_track(s, object, TRACK_FREE, 0UL);
561 set_track(s, object, TRACK_ALLOC, 0UL);
562 }
563
564 static void print_track(const char *s, struct track *t)
565 {
566 if (!t->addr)
567 return;
568
569 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
570 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
571 #ifdef CONFIG_STACKTRACE
572 {
573 int i;
574 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
575 if (t->addrs[i])
576 pr_err("\t%pS\n", (void *)t->addrs[i]);
577 else
578 break;
579 }
580 #endif
581 }
582
583 static void print_tracking(struct kmem_cache *s, void *object)
584 {
585 if (!(s->flags & SLAB_STORE_USER))
586 return;
587
588 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
589 print_track("Freed", get_track(s, object, TRACK_FREE));
590 }
591
592 static void print_page_info(struct page *page)
593 {
594 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
595 page, page->objects, page->inuse, page->freelist, page->flags);
596
597 }
598
599 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
600 {
601 struct va_format vaf;
602 va_list args;
603
604 va_start(args, fmt);
605 vaf.fmt = fmt;
606 vaf.va = &args;
607 pr_err("=============================================================================\n");
608 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
609 pr_err("-----------------------------------------------------------------------------\n\n");
610
611 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
612 va_end(args);
613 }
614
615 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
616 {
617 struct va_format vaf;
618 va_list args;
619
620 va_start(args, fmt);
621 vaf.fmt = fmt;
622 vaf.va = &args;
623 pr_err("FIX %s: %pV\n", s->name, &vaf);
624 va_end(args);
625 }
626
627 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
628 {
629 unsigned int off; /* Offset of last byte */
630 u8 *addr = page_address(page);
631
632 print_tracking(s, p);
633
634 print_page_info(page);
635
636 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
637 p, p - addr, get_freepointer(s, p));
638
639 if (s->flags & SLAB_RED_ZONE)
640 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
641 s->red_left_pad);
642 else if (p > addr + 16)
643 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
644
645 print_section(KERN_ERR, "Object ", p,
646 min_t(unsigned long, s->object_size, PAGE_SIZE));
647 if (s->flags & SLAB_RED_ZONE)
648 print_section(KERN_ERR, "Redzone ", p + s->object_size,
649 s->inuse - s->object_size);
650
651 if (s->offset)
652 off = s->offset + sizeof(void *);
653 else
654 off = s->inuse;
655
656 if (s->flags & SLAB_STORE_USER)
657 off += 2 * sizeof(struct track);
658
659 off += kasan_metadata_size(s);
660
661 if (off != size_from_object(s))
662 /* Beginning of the filler is the free pointer */
663 print_section(KERN_ERR, "Padding ", p + off,
664 size_from_object(s) - off);
665
666 dump_stack();
667 }
668
669 void object_err(struct kmem_cache *s, struct page *page,
670 u8 *object, char *reason)
671 {
672 slab_bug(s, "%s", reason);
673 print_trailer(s, page, object);
674 }
675
676 static void slab_err(struct kmem_cache *s, struct page *page,
677 const char *fmt, ...)
678 {
679 va_list args;
680 char buf[100];
681
682 va_start(args, fmt);
683 vsnprintf(buf, sizeof(buf), fmt, args);
684 va_end(args);
685 slab_bug(s, "%s", buf);
686 print_page_info(page);
687 dump_stack();
688 }
689
690 static void init_object(struct kmem_cache *s, void *object, u8 val)
691 {
692 u8 *p = object;
693
694 if (s->flags & SLAB_RED_ZONE)
695 memset(p - s->red_left_pad, val, s->red_left_pad);
696
697 if (s->flags & __OBJECT_POISON) {
698 memset(p, POISON_FREE, s->object_size - 1);
699 p[s->object_size - 1] = POISON_END;
700 }
701
702 if (s->flags & SLAB_RED_ZONE)
703 memset(p + s->object_size, val, s->inuse - s->object_size);
704 }
705
706 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
707 void *from, void *to)
708 {
709 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
710 memset(from, data, to - from);
711 }
712
713 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
714 u8 *object, char *what,
715 u8 *start, unsigned int value, unsigned int bytes)
716 {
717 u8 *fault;
718 u8 *end;
719
720 metadata_access_enable();
721 fault = memchr_inv(start, value, bytes);
722 metadata_access_disable();
723 if (!fault)
724 return 1;
725
726 end = start + bytes;
727 while (end > fault && end[-1] == value)
728 end--;
729
730 slab_bug(s, "%s overwritten", what);
731 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
732 fault, end - 1, fault[0], value);
733 print_trailer(s, page, object);
734
735 restore_bytes(s, what, value, fault, end);
736 return 0;
737 }
738
739 /*
740 * Object layout:
741 *
742 * object address
743 * Bytes of the object to be managed.
744 * If the freepointer may overlay the object then the free
745 * pointer is the first word of the object.
746 *
747 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
748 * 0xa5 (POISON_END)
749 *
750 * object + s->object_size
751 * Padding to reach word boundary. This is also used for Redzoning.
752 * Padding is extended by another word if Redzoning is enabled and
753 * object_size == inuse.
754 *
755 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
756 * 0xcc (RED_ACTIVE) for objects in use.
757 *
758 * object + s->inuse
759 * Meta data starts here.
760 *
761 * A. Free pointer (if we cannot overwrite object on free)
762 * B. Tracking data for SLAB_STORE_USER
763 * C. Padding to reach required alignment boundary or at mininum
764 * one word if debugging is on to be able to detect writes
765 * before the word boundary.
766 *
767 * Padding is done using 0x5a (POISON_INUSE)
768 *
769 * object + s->size
770 * Nothing is used beyond s->size.
771 *
772 * If slabcaches are merged then the object_size and inuse boundaries are mostly
773 * ignored. And therefore no slab options that rely on these boundaries
774 * may be used with merged slabcaches.
775 */
776
777 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
778 {
779 unsigned long off = s->inuse; /* The end of info */
780
781 if (s->offset)
782 /* Freepointer is placed after the object. */
783 off += sizeof(void *);
784
785 if (s->flags & SLAB_STORE_USER)
786 /* We also have user information there */
787 off += 2 * sizeof(struct track);
788
789 off += kasan_metadata_size(s);
790
791 if (size_from_object(s) == off)
792 return 1;
793
794 return check_bytes_and_report(s, page, p, "Object padding",
795 p + off, POISON_INUSE, size_from_object(s) - off);
796 }
797
798 /* Check the pad bytes at the end of a slab page */
799 static int slab_pad_check(struct kmem_cache *s, struct page *page)
800 {
801 u8 *start;
802 u8 *fault;
803 u8 *end;
804 int length;
805 int remainder;
806
807 if (!(s->flags & SLAB_POISON))
808 return 1;
809
810 start = page_address(page);
811 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
812 end = start + length;
813 remainder = length % s->size;
814 if (!remainder)
815 return 1;
816
817 metadata_access_enable();
818 fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
819 metadata_access_disable();
820 if (!fault)
821 return 1;
822 while (end > fault && end[-1] == POISON_INUSE)
823 end--;
824
825 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
826 print_section(KERN_ERR, "Padding ", end - remainder, remainder);
827
828 restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
829 return 0;
830 }
831
832 static int check_object(struct kmem_cache *s, struct page *page,
833 void *object, u8 val)
834 {
835 u8 *p = object;
836 u8 *endobject = object + s->object_size;
837
838 if (s->flags & SLAB_RED_ZONE) {
839 if (!check_bytes_and_report(s, page, object, "Redzone",
840 object - s->red_left_pad, val, s->red_left_pad))
841 return 0;
842
843 if (!check_bytes_and_report(s, page, object, "Redzone",
844 endobject, val, s->inuse - s->object_size))
845 return 0;
846 } else {
847 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
848 check_bytes_and_report(s, page, p, "Alignment padding",
849 endobject, POISON_INUSE,
850 s->inuse - s->object_size);
851 }
852 }
853
854 if (s->flags & SLAB_POISON) {
855 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
856 (!check_bytes_and_report(s, page, p, "Poison", p,
857 POISON_FREE, s->object_size - 1) ||
858 !check_bytes_and_report(s, page, p, "Poison",
859 p + s->object_size - 1, POISON_END, 1)))
860 return 0;
861 /*
862 * check_pad_bytes cleans up on its own.
863 */
864 check_pad_bytes(s, page, p);
865 }
866
867 if (!s->offset && val == SLUB_RED_ACTIVE)
868 /*
869 * Object and freepointer overlap. Cannot check
870 * freepointer while object is allocated.
871 */
872 return 1;
873
874 /* Check free pointer validity */
875 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
876 object_err(s, page, p, "Freepointer corrupt");
877 /*
878 * No choice but to zap it and thus lose the remainder
879 * of the free objects in this slab. May cause
880 * another error because the object count is now wrong.
881 */
882 set_freepointer(s, p, NULL);
883 return 0;
884 }
885 return 1;
886 }
887
888 static int check_slab(struct kmem_cache *s, struct page *page)
889 {
890 int maxobj;
891
892 VM_BUG_ON(!irqs_disabled());
893
894 if (!PageSlab(page)) {
895 slab_err(s, page, "Not a valid slab page");
896 return 0;
897 }
898
899 maxobj = order_objects(compound_order(page), s->size, s->reserved);
900 if (page->objects > maxobj) {
901 slab_err(s, page, "objects %u > max %u",
902 page->objects, maxobj);
903 return 0;
904 }
905 if (page->inuse > page->objects) {
906 slab_err(s, page, "inuse %u > max %u",
907 page->inuse, page->objects);
908 return 0;
909 }
910 /* Slab_pad_check fixes things up after itself */
911 slab_pad_check(s, page);
912 return 1;
913 }
914
915 /*
916 * Determine if a certain object on a page is on the freelist. Must hold the
917 * slab lock to guarantee that the chains are in a consistent state.
918 */
919 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
920 {
921 int nr = 0;
922 void *fp;
923 void *object = NULL;
924 int max_objects;
925
926 fp = page->freelist;
927 while (fp && nr <= page->objects) {
928 if (fp == search)
929 return 1;
930 if (!check_valid_pointer(s, page, fp)) {
931 if (object) {
932 object_err(s, page, object,
933 "Freechain corrupt");
934 set_freepointer(s, object, NULL);
935 } else {
936 slab_err(s, page, "Freepointer corrupt");
937 page->freelist = NULL;
938 page->inuse = page->objects;
939 slab_fix(s, "Freelist cleared");
940 return 0;
941 }
942 break;
943 }
944 object = fp;
945 fp = get_freepointer(s, object);
946 nr++;
947 }
948
949 max_objects = order_objects(compound_order(page), s->size, s->reserved);
950 if (max_objects > MAX_OBJS_PER_PAGE)
951 max_objects = MAX_OBJS_PER_PAGE;
952
953 if (page->objects != max_objects) {
954 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
955 page->objects, max_objects);
956 page->objects = max_objects;
957 slab_fix(s, "Number of objects adjusted.");
958 }
959 if (page->inuse != page->objects - nr) {
960 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
961 page->inuse, page->objects - nr);
962 page->inuse = page->objects - nr;
963 slab_fix(s, "Object count adjusted.");
964 }
965 return search == NULL;
966 }
967
968 static void trace(struct kmem_cache *s, struct page *page, void *object,
969 int alloc)
970 {
971 if (s->flags & SLAB_TRACE) {
972 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
973 s->name,
974 alloc ? "alloc" : "free",
975 object, page->inuse,
976 page->freelist);
977
978 if (!alloc)
979 print_section(KERN_INFO, "Object ", (void *)object,
980 s->object_size);
981
982 dump_stack();
983 }
984 }
985
986 /*
987 * Tracking of fully allocated slabs for debugging purposes.
988 */
989 static void add_full(struct kmem_cache *s,
990 struct kmem_cache_node *n, struct page *page)
991 {
992 if (!(s->flags & SLAB_STORE_USER))
993 return;
994
995 lockdep_assert_held(&n->list_lock);
996 list_add(&page->lru, &n->full);
997 }
998
999 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1000 {
1001 if (!(s->flags & SLAB_STORE_USER))
1002 return;
1003
1004 lockdep_assert_held(&n->list_lock);
1005 list_del(&page->lru);
1006 }
1007
1008 /* Tracking of the number of slabs for debugging purposes */
1009 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1010 {
1011 struct kmem_cache_node *n = get_node(s, node);
1012
1013 return atomic_long_read(&n->nr_slabs);
1014 }
1015
1016 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1017 {
1018 return atomic_long_read(&n->nr_slabs);
1019 }
1020
1021 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1022 {
1023 struct kmem_cache_node *n = get_node(s, node);
1024
1025 /*
1026 * May be called early in order to allocate a slab for the
1027 * kmem_cache_node structure. Solve the chicken-egg
1028 * dilemma by deferring the increment of the count during
1029 * bootstrap (see early_kmem_cache_node_alloc).
1030 */
1031 if (likely(n)) {
1032 atomic_long_inc(&n->nr_slabs);
1033 atomic_long_add(objects, &n->total_objects);
1034 }
1035 }
1036 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1037 {
1038 struct kmem_cache_node *n = get_node(s, node);
1039
1040 atomic_long_dec(&n->nr_slabs);
1041 atomic_long_sub(objects, &n->total_objects);
1042 }
1043
1044 /* Object debug checks for alloc/free paths */
1045 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1046 void *object)
1047 {
1048 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1049 return;
1050
1051 init_object(s, object, SLUB_RED_INACTIVE);
1052 init_tracking(s, object);
1053 }
1054
1055 static inline int alloc_consistency_checks(struct kmem_cache *s,
1056 struct page *page,
1057 void *object, unsigned long addr)
1058 {
1059 if (!check_slab(s, page))
1060 return 0;
1061
1062 if (!check_valid_pointer(s, page, object)) {
1063 object_err(s, page, object, "Freelist Pointer check fails");
1064 return 0;
1065 }
1066
1067 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1068 return 0;
1069
1070 return 1;
1071 }
1072
1073 static noinline int alloc_debug_processing(struct kmem_cache *s,
1074 struct page *page,
1075 void *object, unsigned long addr)
1076 {
1077 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1078 if (!alloc_consistency_checks(s, page, object, addr))
1079 goto bad;
1080 }
1081
1082 /* Success perform special debug activities for allocs */
1083 if (s->flags & SLAB_STORE_USER)
1084 set_track(s, object, TRACK_ALLOC, addr);
1085 trace(s, page, object, 1);
1086 init_object(s, object, SLUB_RED_ACTIVE);
1087 return 1;
1088
1089 bad:
1090 if (PageSlab(page)) {
1091 /*
1092 * If this is a slab page then lets do the best we can
1093 * to avoid issues in the future. Marking all objects
1094 * as used avoids touching the remaining objects.
1095 */
1096 slab_fix(s, "Marking all objects used");
1097 page->inuse = page->objects;
1098 page->freelist = NULL;
1099 }
1100 return 0;
1101 }
1102
1103 static inline int free_consistency_checks(struct kmem_cache *s,
1104 struct page *page, void *object, unsigned long addr)
1105 {
1106 if (!check_valid_pointer(s, page, object)) {
1107 slab_err(s, page, "Invalid object pointer 0x%p", object);
1108 return 0;
1109 }
1110
1111 if (on_freelist(s, page, object)) {
1112 object_err(s, page, object, "Object already free");
1113 return 0;
1114 }
1115
1116 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1117 return 0;
1118
1119 if (unlikely(s != page->slab_cache)) {
1120 if (!PageSlab(page)) {
1121 slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1122 object);
1123 } else if (!page->slab_cache) {
1124 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1125 object);
1126 dump_stack();
1127 } else
1128 object_err(s, page, object,
1129 "page slab pointer corrupt.");
1130 return 0;
1131 }
1132 return 1;
1133 }
1134
1135 /* Supports checking bulk free of a constructed freelist */
1136 static noinline int free_debug_processing(
1137 struct kmem_cache *s, struct page *page,
1138 void *head, void *tail, int bulk_cnt,
1139 unsigned long addr)
1140 {
1141 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1142 void *object = head;
1143 int cnt = 0;
1144 unsigned long uninitialized_var(flags);
1145 int ret = 0;
1146
1147 spin_lock_irqsave(&n->list_lock, flags);
1148 slab_lock(page);
1149
1150 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1151 if (!check_slab(s, page))
1152 goto out;
1153 }
1154
1155 next_object:
1156 cnt++;
1157
1158 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1159 if (!free_consistency_checks(s, page, object, addr))
1160 goto out;
1161 }
1162
1163 if (s->flags & SLAB_STORE_USER)
1164 set_track(s, object, TRACK_FREE, addr);
1165 trace(s, page, object, 0);
1166 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1167 init_object(s, object, SLUB_RED_INACTIVE);
1168
1169 /* Reached end of constructed freelist yet? */
1170 if (object != tail) {
1171 object = get_freepointer(s, object);
1172 goto next_object;
1173 }
1174 ret = 1;
1175
1176 out:
1177 if (cnt != bulk_cnt)
1178 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1179 bulk_cnt, cnt);
1180
1181 slab_unlock(page);
1182 spin_unlock_irqrestore(&n->list_lock, flags);
1183 if (!ret)
1184 slab_fix(s, "Object at 0x%p not freed", object);
1185 return ret;
1186 }
1187
1188 static int __init setup_slub_debug(char *str)
1189 {
1190 slub_debug = DEBUG_DEFAULT_FLAGS;
1191 if (*str++ != '=' || !*str)
1192 /*
1193 * No options specified. Switch on full debugging.
1194 */
1195 goto out;
1196
1197 if (*str == ',')
1198 /*
1199 * No options but restriction on slabs. This means full
1200 * debugging for slabs matching a pattern.
1201 */
1202 goto check_slabs;
1203
1204 slub_debug = 0;
1205 if (*str == '-')
1206 /*
1207 * Switch off all debugging measures.
1208 */
1209 goto out;
1210
1211 /*
1212 * Determine which debug features should be switched on
1213 */
1214 for (; *str && *str != ','; str++) {
1215 switch (tolower(*str)) {
1216 case 'f':
1217 slub_debug |= SLAB_CONSISTENCY_CHECKS;
1218 break;
1219 case 'z':
1220 slub_debug |= SLAB_RED_ZONE;
1221 break;
1222 case 'p':
1223 slub_debug |= SLAB_POISON;
1224 break;
1225 case 'u':
1226 slub_debug |= SLAB_STORE_USER;
1227 break;
1228 case 't':
1229 slub_debug |= SLAB_TRACE;
1230 break;
1231 case 'a':
1232 slub_debug |= SLAB_FAILSLAB;
1233 break;
1234 case 'o':
1235 /*
1236 * Avoid enabling debugging on caches if its minimum
1237 * order would increase as a result.
1238 */
1239 disable_higher_order_debug = 1;
1240 break;
1241 default:
1242 pr_err("slub_debug option '%c' unknown. skipped\n",
1243 *str);
1244 }
1245 }
1246
1247 check_slabs:
1248 if (*str == ',')
1249 slub_debug_slabs = str + 1;
1250 out:
1251 return 1;
1252 }
1253
1254 __setup("slub_debug", setup_slub_debug);
1255
1256 unsigned long kmem_cache_flags(unsigned long object_size,
1257 unsigned long flags, const char *name,
1258 void (*ctor)(void *))
1259 {
1260 /*
1261 * Enable debugging if selected on the kernel commandline.
1262 */
1263 if (slub_debug && (!slub_debug_slabs || (name &&
1264 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))))
1265 flags |= slub_debug;
1266
1267 return flags;
1268 }
1269 #else /* !CONFIG_SLUB_DEBUG */
1270 static inline void setup_object_debug(struct kmem_cache *s,
1271 struct page *page, void *object) {}
1272
1273 static inline int alloc_debug_processing(struct kmem_cache *s,
1274 struct page *page, void *object, unsigned long addr) { return 0; }
1275
1276 static inline int free_debug_processing(
1277 struct kmem_cache *s, struct page *page,
1278 void *head, void *tail, int bulk_cnt,
1279 unsigned long addr) { return 0; }
1280
1281 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1282 { return 1; }
1283 static inline int check_object(struct kmem_cache *s, struct page *page,
1284 void *object, u8 val) { return 1; }
1285 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1286 struct page *page) {}
1287 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1288 struct page *page) {}
1289 unsigned long kmem_cache_flags(unsigned long object_size,
1290 unsigned long flags, const char *name,
1291 void (*ctor)(void *))
1292 {
1293 return flags;
1294 }
1295 #define slub_debug 0
1296
1297 #define disable_higher_order_debug 0
1298
1299 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1300 { return 0; }
1301 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1302 { return 0; }
1303 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1304 int objects) {}
1305 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1306 int objects) {}
1307
1308 #endif /* CONFIG_SLUB_DEBUG */
1309
1310 /*
1311 * Hooks for other subsystems that check memory allocations. In a typical
1312 * production configuration these hooks all should produce no code at all.
1313 */
1314 static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1315 {
1316 kmemleak_alloc(ptr, size, 1, flags);
1317 kasan_kmalloc_large(ptr, size, flags);
1318 }
1319
1320 static inline void kfree_hook(const void *x)
1321 {
1322 kmemleak_free(x);
1323 kasan_kfree_large(x);
1324 }
1325
1326 static inline void *slab_free_hook(struct kmem_cache *s, void *x)
1327 {
1328 void *freeptr;
1329
1330 kmemleak_free_recursive(x, s->flags);
1331
1332 /*
1333 * Trouble is that we may no longer disable interrupts in the fast path
1334 * So in order to make the debug calls that expect irqs to be
1335 * disabled we need to disable interrupts temporarily.
1336 */
1337 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1338 {
1339 unsigned long flags;
1340
1341 local_irq_save(flags);
1342 kmemcheck_slab_free(s, x, s->object_size);
1343 debug_check_no_locks_freed(x, s->object_size);
1344 local_irq_restore(flags);
1345 }
1346 #endif
1347 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1348 debug_check_no_obj_freed(x, s->object_size);
1349
1350 freeptr = get_freepointer(s, x);
1351 /*
1352 * kasan_slab_free() may put x into memory quarantine, delaying its
1353 * reuse. In this case the object's freelist pointer is changed.
1354 */
1355 kasan_slab_free(s, x);
1356 return freeptr;
1357 }
1358
1359 static inline void slab_free_freelist_hook(struct kmem_cache *s,
1360 void *head, void *tail)
1361 {
1362 /*
1363 * Compiler cannot detect this function can be removed if slab_free_hook()
1364 * evaluates to nothing. Thus, catch all relevant config debug options here.
1365 */
1366 #if defined(CONFIG_KMEMCHECK) || \
1367 defined(CONFIG_LOCKDEP) || \
1368 defined(CONFIG_DEBUG_KMEMLEAK) || \
1369 defined(CONFIG_DEBUG_OBJECTS_FREE) || \
1370 defined(CONFIG_KASAN)
1371
1372 void *object = head;
1373 void *tail_obj = tail ? : head;
1374 void *freeptr;
1375
1376 do {
1377 freeptr = slab_free_hook(s, object);
1378 } while ((object != tail_obj) && (object = freeptr));
1379 #endif
1380 }
1381
1382 static void setup_object(struct kmem_cache *s, struct page *page,
1383 void *object)
1384 {
1385 setup_object_debug(s, page, object);
1386 kasan_init_slab_obj(s, object);
1387 if (unlikely(s->ctor)) {
1388 kasan_unpoison_object_data(s, object);
1389 s->ctor(object);
1390 kasan_poison_object_data(s, object);
1391 }
1392 }
1393
1394 /*
1395 * Slab allocation and freeing
1396 */
1397 static inline struct page *alloc_slab_page(struct kmem_cache *s,
1398 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1399 {
1400 struct page *page;
1401 int order = oo_order(oo);
1402
1403 flags |= __GFP_NOTRACK;
1404
1405 if (node == NUMA_NO_NODE)
1406 page = alloc_pages(flags, order);
1407 else
1408 page = __alloc_pages_node(node, flags, order);
1409
1410 if (page && memcg_charge_slab(page, flags, order, s)) {
1411 __free_pages(page, order);
1412 page = NULL;
1413 }
1414
1415 return page;
1416 }
1417
1418 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1419 /* Pre-initialize the random sequence cache */
1420 static int init_cache_random_seq(struct kmem_cache *s)
1421 {
1422 int err;
1423 unsigned long i, count = oo_objects(s->oo);
1424
1425 err = cache_random_seq_create(s, count, GFP_KERNEL);
1426 if (err) {
1427 pr_err("SLUB: Unable to initialize free list for %s\n",
1428 s->name);
1429 return err;
1430 }
1431
1432 /* Transform to an offset on the set of pages */
1433 if (s->random_seq) {
1434 for (i = 0; i < count; i++)
1435 s->random_seq[i] *= s->size;
1436 }
1437 return 0;
1438 }
1439
1440 /* Initialize each random sequence freelist per cache */
1441 static void __init init_freelist_randomization(void)
1442 {
1443 struct kmem_cache *s;
1444
1445 mutex_lock(&slab_mutex);
1446
1447 list_for_each_entry(s, &slab_caches, list)
1448 init_cache_random_seq(s);
1449
1450 mutex_unlock(&slab_mutex);
1451 }
1452
1453 /* Get the next entry on the pre-computed freelist randomized */
1454 static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1455 unsigned long *pos, void *start,
1456 unsigned long page_limit,
1457 unsigned long freelist_count)
1458 {
1459 unsigned int idx;
1460
1461 /*
1462 * If the target page allocation failed, the number of objects on the
1463 * page might be smaller than the usual size defined by the cache.
1464 */
1465 do {
1466 idx = s->random_seq[*pos];
1467 *pos += 1;
1468 if (*pos >= freelist_count)
1469 *pos = 0;
1470 } while (unlikely(idx >= page_limit));
1471
1472 return (char *)start + idx;
1473 }
1474
1475 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1476 static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1477 {
1478 void *start;
1479 void *cur;
1480 void *next;
1481 unsigned long idx, pos, page_limit, freelist_count;
1482
1483 if (page->objects < 2 || !s->random_seq)
1484 return false;
1485
1486 freelist_count = oo_objects(s->oo);
1487 pos = get_random_int() % freelist_count;
1488
1489 page_limit = page->objects * s->size;
1490 start = fixup_red_left(s, page_address(page));
1491
1492 /* First entry is used as the base of the freelist */
1493 cur = next_freelist_entry(s, page, &pos, start, page_limit,
1494 freelist_count);
1495 page->freelist = cur;
1496
1497 for (idx = 1; idx < page->objects; idx++) {
1498 setup_object(s, page, cur);
1499 next = next_freelist_entry(s, page, &pos, start, page_limit,
1500 freelist_count);
1501 set_freepointer(s, cur, next);
1502 cur = next;
1503 }
1504 setup_object(s, page, cur);
1505 set_freepointer(s, cur, NULL);
1506
1507 return true;
1508 }
1509 #else
1510 static inline int init_cache_random_seq(struct kmem_cache *s)
1511 {
1512 return 0;
1513 }
1514 static inline void init_freelist_randomization(void) { }
1515 static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1516 {
1517 return false;
1518 }
1519 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1520
1521 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1522 {
1523 struct page *page;
1524 struct kmem_cache_order_objects oo = s->oo;
1525 gfp_t alloc_gfp;
1526 void *start, *p;
1527 int idx, order;
1528 bool shuffle;
1529
1530 flags &= gfp_allowed_mask;
1531
1532 if (gfpflags_allow_blocking(flags))
1533 local_irq_enable();
1534
1535 flags |= s->allocflags;
1536
1537 /*
1538 * Let the initial higher-order allocation fail under memory pressure
1539 * so we fall-back to the minimum order allocation.
1540 */
1541 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1542 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1543 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1544
1545 page = alloc_slab_page(s, alloc_gfp, node, oo);
1546 if (unlikely(!page)) {
1547 oo = s->min;
1548 alloc_gfp = flags;
1549 /*
1550 * Allocation may have failed due to fragmentation.
1551 * Try a lower order alloc if possible
1552 */
1553 page = alloc_slab_page(s, alloc_gfp, node, oo);
1554 if (unlikely(!page))
1555 goto out;
1556 stat(s, ORDER_FALLBACK);
1557 }
1558
1559 if (kmemcheck_enabled &&
1560 !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1561 int pages = 1 << oo_order(oo);
1562
1563 kmemcheck_alloc_shadow(page, oo_order(oo), alloc_gfp, node);
1564
1565 /*
1566 * Objects from caches that have a constructor don't get
1567 * cleared when they're allocated, so we need to do it here.
1568 */
1569 if (s->ctor)
1570 kmemcheck_mark_uninitialized_pages(page, pages);
1571 else
1572 kmemcheck_mark_unallocated_pages(page, pages);
1573 }
1574
1575 page->objects = oo_objects(oo);
1576
1577 order = compound_order(page);
1578 page->slab_cache = s;
1579 __SetPageSlab(page);
1580 if (page_is_pfmemalloc(page))
1581 SetPageSlabPfmemalloc(page);
1582
1583 start = page_address(page);
1584
1585 if (unlikely(s->flags & SLAB_POISON))
1586 memset(start, POISON_INUSE, PAGE_SIZE << order);
1587
1588 kasan_poison_slab(page);
1589
1590 shuffle = shuffle_freelist(s, page);
1591
1592 if (!shuffle) {
1593 for_each_object_idx(p, idx, s, start, page->objects) {
1594 setup_object(s, page, p);
1595 if (likely(idx < page->objects))
1596 set_freepointer(s, p, p + s->size);
1597 else
1598 set_freepointer(s, p, NULL);
1599 }
1600 page->freelist = fixup_red_left(s, start);
1601 }
1602
1603 page->inuse = page->objects;
1604 page->frozen = 1;
1605
1606 out:
1607 if (gfpflags_allow_blocking(flags))
1608 local_irq_disable();
1609 if (!page)
1610 return NULL;
1611
1612 mod_zone_page_state(page_zone(page),
1613 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1614 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1615 1 << oo_order(oo));
1616
1617 inc_slabs_node(s, page_to_nid(page), page->objects);
1618
1619 return page;
1620 }
1621
1622 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1623 {
1624 if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1625 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1626 flags &= ~GFP_SLAB_BUG_MASK;
1627 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1628 invalid_mask, &invalid_mask, flags, &flags);
1629 }
1630
1631 return allocate_slab(s,
1632 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1633 }
1634
1635 static void __free_slab(struct kmem_cache *s, struct page *page)
1636 {
1637 int order = compound_order(page);
1638 int pages = 1 << order;
1639
1640 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1641 void *p;
1642
1643 slab_pad_check(s, page);
1644 for_each_object(p, s, page_address(page),
1645 page->objects)
1646 check_object(s, page, p, SLUB_RED_INACTIVE);
1647 }
1648
1649 kmemcheck_free_shadow(page, compound_order(page));
1650
1651 mod_zone_page_state(page_zone(page),
1652 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1653 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1654 -pages);
1655
1656 __ClearPageSlabPfmemalloc(page);
1657 __ClearPageSlab(page);
1658
1659 page_mapcount_reset(page);
1660 if (current->reclaim_state)
1661 current->reclaim_state->reclaimed_slab += pages;
1662 memcg_uncharge_slab(page, order, s);
1663 __free_pages(page, order);
1664 }
1665
1666 #define need_reserve_slab_rcu \
1667 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1668
1669 static void rcu_free_slab(struct rcu_head *h)
1670 {
1671 struct page *page;
1672
1673 if (need_reserve_slab_rcu)
1674 page = virt_to_head_page(h);
1675 else
1676 page = container_of((struct list_head *)h, struct page, lru);
1677
1678 __free_slab(page->slab_cache, page);
1679 }
1680
1681 static void free_slab(struct kmem_cache *s, struct page *page)
1682 {
1683 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1684 struct rcu_head *head;
1685
1686 if (need_reserve_slab_rcu) {
1687 int order = compound_order(page);
1688 int offset = (PAGE_SIZE << order) - s->reserved;
1689
1690 VM_BUG_ON(s->reserved != sizeof(*head));
1691 head = page_address(page) + offset;
1692 } else {
1693 head = &page->rcu_head;
1694 }
1695
1696 call_rcu(head, rcu_free_slab);
1697 } else
1698 __free_slab(s, page);
1699 }
1700
1701 static void discard_slab(struct kmem_cache *s, struct page *page)
1702 {
1703 dec_slabs_node(s, page_to_nid(page), page->objects);
1704 free_slab(s, page);
1705 }
1706
1707 /*
1708 * Management of partially allocated slabs.
1709 */
1710 static inline void
1711 __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1712 {
1713 n->nr_partial++;
1714 if (tail == DEACTIVATE_TO_TAIL)
1715 list_add_tail(&page->lru, &n->partial);
1716 else
1717 list_add(&page->lru, &n->partial);
1718 }
1719
1720 static inline void add_partial(struct kmem_cache_node *n,
1721 struct page *page, int tail)
1722 {
1723 lockdep_assert_held(&n->list_lock);
1724 __add_partial(n, page, tail);
1725 }
1726
1727 static inline void remove_partial(struct kmem_cache_node *n,
1728 struct page *page)
1729 {
1730 lockdep_assert_held(&n->list_lock);
1731 list_del(&page->lru);
1732 n->nr_partial--;
1733 }
1734
1735 /*
1736 * Remove slab from the partial list, freeze it and
1737 * return the pointer to the freelist.
1738 *
1739 * Returns a list of objects or NULL if it fails.
1740 */
1741 static inline void *acquire_slab(struct kmem_cache *s,
1742 struct kmem_cache_node *n, struct page *page,
1743 int mode, int *objects)
1744 {
1745 void *freelist;
1746 unsigned long counters;
1747 struct page new;
1748
1749 lockdep_assert_held(&n->list_lock);
1750
1751 /*
1752 * Zap the freelist and set the frozen bit.
1753 * The old freelist is the list of objects for the
1754 * per cpu allocation list.
1755 */
1756 freelist = page->freelist;
1757 counters = page->counters;
1758 new.counters = counters;
1759 *objects = new.objects - new.inuse;
1760 if (mode) {
1761 new.inuse = page->objects;
1762 new.freelist = NULL;
1763 } else {
1764 new.freelist = freelist;
1765 }
1766
1767 VM_BUG_ON(new.frozen);
1768 new.frozen = 1;
1769
1770 if (!__cmpxchg_double_slab(s, page,
1771 freelist, counters,
1772 new.freelist, new.counters,
1773 "acquire_slab"))
1774 return NULL;
1775
1776 remove_partial(n, page);
1777 WARN_ON(!freelist);
1778 return freelist;
1779 }
1780
1781 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1782 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1783
1784 /*
1785 * Try to allocate a partial slab from a specific node.
1786 */
1787 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1788 struct kmem_cache_cpu *c, gfp_t flags)
1789 {
1790 struct page *page, *page2;
1791 void *object = NULL;
1792 int available = 0;
1793 int objects;
1794
1795 /*
1796 * Racy check. If we mistakenly see no partial slabs then we
1797 * just allocate an empty slab. If we mistakenly try to get a
1798 * partial slab and there is none available then get_partials()
1799 * will return NULL.
1800 */
1801 if (!n || !n->nr_partial)
1802 return NULL;
1803
1804 spin_lock(&n->list_lock);
1805 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1806 void *t;
1807
1808 if (!pfmemalloc_match(page, flags))
1809 continue;
1810
1811 t = acquire_slab(s, n, page, object == NULL, &objects);
1812 if (!t)
1813 break;
1814
1815 available += objects;
1816 if (!object) {
1817 c->page = page;
1818 stat(s, ALLOC_FROM_PARTIAL);
1819 object = t;
1820 } else {
1821 put_cpu_partial(s, page, 0);
1822 stat(s, CPU_PARTIAL_NODE);
1823 }
1824 if (!kmem_cache_has_cpu_partial(s)
1825 || available > s->cpu_partial / 2)
1826 break;
1827
1828 }
1829 spin_unlock(&n->list_lock);
1830 return object;
1831 }
1832
1833 /*
1834 * Get a page from somewhere. Search in increasing NUMA distances.
1835 */
1836 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1837 struct kmem_cache_cpu *c)
1838 {
1839 #ifdef CONFIG_NUMA
1840 struct zonelist *zonelist;
1841 struct zoneref *z;
1842 struct zone *zone;
1843 enum zone_type high_zoneidx = gfp_zone(flags);
1844 void *object;
1845 unsigned int cpuset_mems_cookie;
1846
1847 /*
1848 * The defrag ratio allows a configuration of the tradeoffs between
1849 * inter node defragmentation and node local allocations. A lower
1850 * defrag_ratio increases the tendency to do local allocations
1851 * instead of attempting to obtain partial slabs from other nodes.
1852 *
1853 * If the defrag_ratio is set to 0 then kmalloc() always
1854 * returns node local objects. If the ratio is higher then kmalloc()
1855 * may return off node objects because partial slabs are obtained
1856 * from other nodes and filled up.
1857 *
1858 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
1859 * (which makes defrag_ratio = 1000) then every (well almost)
1860 * allocation will first attempt to defrag slab caches on other nodes.
1861 * This means scanning over all nodes to look for partial slabs which
1862 * may be expensive if we do it every time we are trying to find a slab
1863 * with available objects.
1864 */
1865 if (!s->remote_node_defrag_ratio ||
1866 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1867 return NULL;
1868
1869 do {
1870 cpuset_mems_cookie = read_mems_allowed_begin();
1871 zonelist = node_zonelist(mempolicy_slab_node(), flags);
1872 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1873 struct kmem_cache_node *n;
1874
1875 n = get_node(s, zone_to_nid(zone));
1876
1877 if (n && cpuset_zone_allowed(zone, flags) &&
1878 n->nr_partial > s->min_partial) {
1879 object = get_partial_node(s, n, c, flags);
1880 if (object) {
1881 /*
1882 * Don't check read_mems_allowed_retry()
1883 * here - if mems_allowed was updated in
1884 * parallel, that was a harmless race
1885 * between allocation and the cpuset
1886 * update
1887 */
1888 return object;
1889 }
1890 }
1891 }
1892 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1893 #endif
1894 return NULL;
1895 }
1896
1897 /*
1898 * Get a partial page, lock it and return it.
1899 */
1900 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1901 struct kmem_cache_cpu *c)
1902 {
1903 void *object;
1904 int searchnode = node;
1905
1906 if (node == NUMA_NO_NODE)
1907 searchnode = numa_mem_id();
1908 else if (!node_present_pages(node))
1909 searchnode = node_to_mem_node(node);
1910
1911 object = get_partial_node(s, get_node(s, searchnode), c, flags);
1912 if (object || node != NUMA_NO_NODE)
1913 return object;
1914
1915 return get_any_partial(s, flags, c);
1916 }
1917
1918 #ifdef CONFIG_PREEMPT
1919 /*
1920 * Calculate the next globally unique transaction for disambiguiation
1921 * during cmpxchg. The transactions start with the cpu number and are then
1922 * incremented by CONFIG_NR_CPUS.
1923 */
1924 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1925 #else
1926 /*
1927 * No preemption supported therefore also no need to check for
1928 * different cpus.
1929 */
1930 #define TID_STEP 1
1931 #endif
1932
1933 static inline unsigned long next_tid(unsigned long tid)
1934 {
1935 return tid + TID_STEP;
1936 }
1937
1938 static inline unsigned int tid_to_cpu(unsigned long tid)
1939 {
1940 return tid % TID_STEP;
1941 }
1942
1943 static inline unsigned long tid_to_event(unsigned long tid)
1944 {
1945 return tid / TID_STEP;
1946 }
1947
1948 static inline unsigned int init_tid(int cpu)
1949 {
1950 return cpu;
1951 }
1952
1953 static inline void note_cmpxchg_failure(const char *n,
1954 const struct kmem_cache *s, unsigned long tid)
1955 {
1956 #ifdef SLUB_DEBUG_CMPXCHG
1957 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1958
1959 pr_info("%s %s: cmpxchg redo ", n, s->name);
1960
1961 #ifdef CONFIG_PREEMPT
1962 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1963 pr_warn("due to cpu change %d -> %d\n",
1964 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1965 else
1966 #endif
1967 if (tid_to_event(tid) != tid_to_event(actual_tid))
1968 pr_warn("due to cpu running other code. Event %ld->%ld\n",
1969 tid_to_event(tid), tid_to_event(actual_tid));
1970 else
1971 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
1972 actual_tid, tid, next_tid(tid));
1973 #endif
1974 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1975 }
1976
1977 static void init_kmem_cache_cpus(struct kmem_cache *s)
1978 {
1979 int cpu;
1980
1981 for_each_possible_cpu(cpu)
1982 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1983 }
1984
1985 /*
1986 * Remove the cpu slab
1987 */
1988 static void deactivate_slab(struct kmem_cache *s, struct page *page,
1989 void *freelist)
1990 {
1991 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1992 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1993 int lock = 0;
1994 enum slab_modes l = M_NONE, m = M_NONE;
1995 void *nextfree;
1996 int tail = DEACTIVATE_TO_HEAD;
1997 struct page new;
1998 struct page old;
1999
2000 if (page->freelist) {
2001 stat(s, DEACTIVATE_REMOTE_FREES);
2002 tail = DEACTIVATE_TO_TAIL;
2003 }
2004
2005 /*
2006 * Stage one: Free all available per cpu objects back
2007 * to the page freelist while it is still frozen. Leave the
2008 * last one.
2009 *
2010 * There is no need to take the list->lock because the page
2011 * is still frozen.
2012 */
2013 while (freelist && (nextfree = get_freepointer(s, freelist))) {
2014 void *prior;
2015 unsigned long counters;
2016
2017 do {
2018 prior = page->freelist;
2019 counters = page->counters;
2020 set_freepointer(s, freelist, prior);
2021 new.counters = counters;
2022 new.inuse--;
2023 VM_BUG_ON(!new.frozen);
2024
2025 } while (!__cmpxchg_double_slab(s, page,
2026 prior, counters,
2027 freelist, new.counters,
2028 "drain percpu freelist"));
2029
2030 freelist = nextfree;
2031 }
2032
2033 /*
2034 * Stage two: Ensure that the page is unfrozen while the
2035 * list presence reflects the actual number of objects
2036 * during unfreeze.
2037 *
2038 * We setup the list membership and then perform a cmpxchg
2039 * with the count. If there is a mismatch then the page
2040 * is not unfrozen but the page is on the wrong list.
2041 *
2042 * Then we restart the process which may have to remove
2043 * the page from the list that we just put it on again
2044 * because the number of objects in the slab may have
2045 * changed.
2046 */
2047 redo:
2048
2049 old.freelist = page->freelist;
2050 old.counters = page->counters;
2051 VM_BUG_ON(!old.frozen);
2052
2053 /* Determine target state of the slab */
2054 new.counters = old.counters;
2055 if (freelist) {
2056 new.inuse--;
2057 set_freepointer(s, freelist, old.freelist);
2058 new.freelist = freelist;
2059 } else
2060 new.freelist = old.freelist;
2061
2062 new.frozen = 0;
2063
2064 if (!new.inuse && n->nr_partial >= s->min_partial)
2065 m = M_FREE;
2066 else if (new.freelist) {
2067 m = M_PARTIAL;
2068 if (!lock) {
2069 lock = 1;
2070 /*
2071 * Taking the spinlock removes the possiblity
2072 * that acquire_slab() will see a slab page that
2073 * is frozen
2074 */
2075 spin_lock(&n->list_lock);
2076 }
2077 } else {
2078 m = M_FULL;
2079 if (kmem_cache_debug(s) && !lock) {
2080 lock = 1;
2081 /*
2082 * This also ensures that the scanning of full
2083 * slabs from diagnostic functions will not see
2084 * any frozen slabs.
2085 */
2086 spin_lock(&n->list_lock);
2087 }
2088 }
2089
2090 if (l != m) {
2091
2092 if (l == M_PARTIAL)
2093
2094 remove_partial(n, page);
2095
2096 else if (l == M_FULL)
2097
2098 remove_full(s, n, page);
2099
2100 if (m == M_PARTIAL) {
2101
2102 add_partial(n, page, tail);
2103 stat(s, tail);
2104
2105 } else if (m == M_FULL) {
2106
2107 stat(s, DEACTIVATE_FULL);
2108 add_full(s, n, page);
2109
2110 }
2111 }
2112
2113 l = m;
2114 if (!__cmpxchg_double_slab(s, page,
2115 old.freelist, old.counters,
2116 new.freelist, new.counters,
2117 "unfreezing slab"))
2118 goto redo;
2119
2120 if (lock)
2121 spin_unlock(&n->list_lock);
2122
2123 if (m == M_FREE) {
2124 stat(s, DEACTIVATE_EMPTY);
2125 discard_slab(s, page);
2126 stat(s, FREE_SLAB);
2127 }
2128 }
2129
2130 /*
2131 * Unfreeze all the cpu partial slabs.
2132 *
2133 * This function must be called with interrupts disabled
2134 * for the cpu using c (or some other guarantee must be there
2135 * to guarantee no concurrent accesses).
2136 */
2137 static void unfreeze_partials(struct kmem_cache *s,
2138 struct kmem_cache_cpu *c)
2139 {
2140 #ifdef CONFIG_SLUB_CPU_PARTIAL
2141 struct kmem_cache_node *n = NULL, *n2 = NULL;
2142 struct page *page, *discard_page = NULL;
2143
2144 while ((page = c->partial)) {
2145 struct page new;
2146 struct page old;
2147
2148 c->partial = page->next;
2149
2150 n2 = get_node(s, page_to_nid(page));
2151 if (n != n2) {
2152 if (n)
2153 spin_unlock(&n->list_lock);
2154
2155 n = n2;
2156 spin_lock(&n->list_lock);
2157 }
2158
2159 do {
2160
2161 old.freelist = page->freelist;
2162 old.counters = page->counters;
2163 VM_BUG_ON(!old.frozen);
2164
2165 new.counters = old.counters;
2166 new.freelist = old.freelist;
2167
2168 new.frozen = 0;
2169
2170 } while (!__cmpxchg_double_slab(s, page,
2171 old.freelist, old.counters,
2172 new.freelist, new.counters,
2173 "unfreezing slab"));
2174
2175 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2176 page->next = discard_page;
2177 discard_page = page;
2178 } else {
2179 add_partial(n, page, DEACTIVATE_TO_TAIL);
2180 stat(s, FREE_ADD_PARTIAL);
2181 }
2182 }
2183
2184 if (n)
2185 spin_unlock(&n->list_lock);
2186
2187 while (discard_page) {
2188 page = discard_page;
2189 discard_page = discard_page->next;
2190
2191 stat(s, DEACTIVATE_EMPTY);
2192 discard_slab(s, page);
2193 stat(s, FREE_SLAB);
2194 }
2195 #endif
2196 }
2197
2198 /*
2199 * Put a page that was just frozen (in __slab_free) into a partial page
2200 * slot if available. This is done without interrupts disabled and without
2201 * preemption disabled. The cmpxchg is racy and may put the partial page
2202 * onto a random cpus partial slot.
2203 *
2204 * If we did not find a slot then simply move all the partials to the
2205 * per node partial list.
2206 */
2207 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2208 {
2209 #ifdef CONFIG_SLUB_CPU_PARTIAL
2210 struct page *oldpage;
2211 int pages;
2212 int pobjects;
2213
2214 preempt_disable();
2215 do {
2216 pages = 0;
2217 pobjects = 0;
2218 oldpage = this_cpu_read(s->cpu_slab->partial);
2219
2220 if (oldpage) {
2221 pobjects = oldpage->pobjects;
2222 pages = oldpage->pages;
2223 if (drain && pobjects > s->cpu_partial) {
2224 unsigned long flags;
2225 /*
2226 * partial array is full. Move the existing
2227 * set to the per node partial list.
2228 */
2229 local_irq_save(flags);
2230 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2231 local_irq_restore(flags);
2232 oldpage = NULL;
2233 pobjects = 0;
2234 pages = 0;
2235 stat(s, CPU_PARTIAL_DRAIN);
2236 }
2237 }
2238
2239 pages++;
2240 pobjects += page->objects - page->inuse;
2241
2242 page->pages = pages;
2243 page->pobjects = pobjects;
2244 page->next = oldpage;
2245
2246 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2247 != oldpage);
2248 if (unlikely(!s->cpu_partial)) {
2249 unsigned long flags;
2250
2251 local_irq_save(flags);
2252 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2253 local_irq_restore(flags);
2254 }
2255 preempt_enable();
2256 #endif
2257 }
2258
2259 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2260 {
2261 stat(s, CPUSLAB_FLUSH);
2262 deactivate_slab(s, c->page, c->freelist);
2263
2264 c->tid = next_tid(c->tid);
2265 c->page = NULL;
2266 c->freelist = NULL;
2267 }
2268
2269 /*
2270 * Flush cpu slab.
2271 *
2272 * Called from IPI handler with interrupts disabled.
2273 */
2274 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2275 {
2276 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2277
2278 if (likely(c)) {
2279 if (c->page)
2280 flush_slab(s, c);
2281
2282 unfreeze_partials(s, c);
2283 }
2284 }
2285
2286 static void flush_cpu_slab(void *d)
2287 {
2288 struct kmem_cache *s = d;
2289
2290 __flush_cpu_slab(s, smp_processor_id());
2291 }
2292
2293 static bool has_cpu_slab(int cpu, void *info)
2294 {
2295 struct kmem_cache *s = info;
2296 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2297
2298 return c->page || c->partial;
2299 }
2300
2301 static void flush_all(struct kmem_cache *s)
2302 {
2303 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2304 }
2305
2306 /*
2307 * Use the cpu notifier to insure that the cpu slabs are flushed when
2308 * necessary.
2309 */
2310 static int slub_cpu_dead(unsigned int cpu)
2311 {
2312 struct kmem_cache *s;
2313 unsigned long flags;
2314
2315 mutex_lock(&slab_mutex);
2316 list_for_each_entry(s, &slab_caches, list) {
2317 local_irq_save(flags);
2318 __flush_cpu_slab(s, cpu);
2319 local_irq_restore(flags);
2320 }
2321 mutex_unlock(&slab_mutex);
2322 return 0;
2323 }
2324
2325 /*
2326 * Check if the objects in a per cpu structure fit numa
2327 * locality expectations.
2328 */
2329 static inline int node_match(struct page *page, int node)
2330 {
2331 #ifdef CONFIG_NUMA
2332 if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2333 return 0;
2334 #endif
2335 return 1;
2336 }
2337
2338 #ifdef CONFIG_SLUB_DEBUG
2339 static int count_free(struct page *page)
2340 {
2341 return page->objects - page->inuse;
2342 }
2343
2344 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2345 {
2346 return atomic_long_read(&n->total_objects);
2347 }
2348 #endif /* CONFIG_SLUB_DEBUG */
2349
2350 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2351 static unsigned long count_partial(struct kmem_cache_node *n,
2352 int (*get_count)(struct page *))
2353 {
2354 unsigned long flags;
2355 unsigned long x = 0;
2356 struct page *page;
2357
2358 spin_lock_irqsave(&n->list_lock, flags);
2359 list_for_each_entry(page, &n->partial, lru)
2360 x += get_count(page);
2361 spin_unlock_irqrestore(&n->list_lock, flags);
2362 return x;
2363 }
2364 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2365
2366 static noinline void
2367 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2368 {
2369 #ifdef CONFIG_SLUB_DEBUG
2370 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2371 DEFAULT_RATELIMIT_BURST);
2372 int node;
2373 struct kmem_cache_node *n;
2374
2375 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2376 return;
2377
2378 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2379 nid, gfpflags, &gfpflags);
2380 pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
2381 s->name, s->object_size, s->size, oo_order(s->oo),
2382 oo_order(s->min));
2383
2384 if (oo_order(s->min) > get_order(s->object_size))
2385 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2386 s->name);
2387
2388 for_each_kmem_cache_node(s, node, n) {
2389 unsigned long nr_slabs;
2390 unsigned long nr_objs;
2391 unsigned long nr_free;
2392
2393 nr_free = count_partial(n, count_free);
2394 nr_slabs = node_nr_slabs(n);
2395 nr_objs = node_nr_objs(n);
2396
2397 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2398 node, nr_slabs, nr_objs, nr_free);
2399 }
2400 #endif
2401 }
2402
2403 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2404 int node, struct kmem_cache_cpu **pc)
2405 {
2406 void *freelist;
2407 struct kmem_cache_cpu *c = *pc;
2408 struct page *page;
2409
2410 freelist = get_partial(s, flags, node, c);
2411
2412 if (freelist)
2413 return freelist;
2414
2415 page = new_slab(s, flags, node);
2416 if (page) {
2417 c = raw_cpu_ptr(s->cpu_slab);
2418 if (c->page)
2419 flush_slab(s, c);
2420
2421 /*
2422 * No other reference to the page yet so we can
2423 * muck around with it freely without cmpxchg
2424 */
2425 freelist = page->freelist;
2426 page->freelist = NULL;
2427
2428 stat(s, ALLOC_SLAB);
2429 c->page = page;
2430 *pc = c;
2431 } else
2432 freelist = NULL;
2433
2434 return freelist;
2435 }
2436
2437 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2438 {
2439 if (unlikely(PageSlabPfmemalloc(page)))
2440 return gfp_pfmemalloc_allowed(gfpflags);
2441
2442 return true;
2443 }
2444
2445 /*
2446 * Check the page->freelist of a page and either transfer the freelist to the
2447 * per cpu freelist or deactivate the page.
2448 *
2449 * The page is still frozen if the return value is not NULL.
2450 *
2451 * If this function returns NULL then the page has been unfrozen.
2452 *
2453 * This function must be called with interrupt disabled.
2454 */
2455 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2456 {
2457 struct page new;
2458 unsigned long counters;
2459 void *freelist;
2460
2461 do {
2462 freelist = page->freelist;
2463 counters = page->counters;
2464
2465 new.counters = counters;
2466 VM_BUG_ON(!new.frozen);
2467
2468 new.inuse = page->objects;
2469 new.frozen = freelist != NULL;
2470
2471 } while (!__cmpxchg_double_slab(s, page,
2472 freelist, counters,
2473 NULL, new.counters,
2474 "get_freelist"));
2475
2476 return freelist;
2477 }
2478
2479 /*
2480 * Slow path. The lockless freelist is empty or we need to perform
2481 * debugging duties.
2482 *
2483 * Processing is still very fast if new objects have been freed to the
2484 * regular freelist. In that case we simply take over the regular freelist
2485 * as the lockless freelist and zap the regular freelist.
2486 *
2487 * If that is not working then we fall back to the partial lists. We take the
2488 * first element of the freelist as the object to allocate now and move the
2489 * rest of the freelist to the lockless freelist.
2490 *
2491 * And if we were unable to get a new slab from the partial slab lists then
2492 * we need to allocate a new slab. This is the slowest path since it involves
2493 * a call to the page allocator and the setup of a new slab.
2494 *
2495 * Version of __slab_alloc to use when we know that interrupts are
2496 * already disabled (which is the case for bulk allocation).
2497 */
2498 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2499 unsigned long addr, struct kmem_cache_cpu *c)
2500 {
2501 void *freelist;
2502 struct page *page;
2503
2504 page = c->page;
2505 if (!page)
2506 goto new_slab;
2507 redo:
2508
2509 if (unlikely(!node_match(page, node))) {
2510 int searchnode = node;
2511
2512 if (node != NUMA_NO_NODE && !node_present_pages(node))
2513 searchnode = node_to_mem_node(node);
2514
2515 if (unlikely(!node_match(page, searchnode))) {
2516 stat(s, ALLOC_NODE_MISMATCH);
2517 deactivate_slab(s, page, c->freelist);
2518 c->page = NULL;
2519 c->freelist = NULL;
2520 goto new_slab;
2521 }
2522 }
2523
2524 /*
2525 * By rights, we should be searching for a slab page that was
2526 * PFMEMALLOC but right now, we are losing the pfmemalloc
2527 * information when the page leaves the per-cpu allocator
2528 */
2529 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2530 deactivate_slab(s, page, c->freelist);
2531 c->page = NULL;
2532 c->freelist = NULL;
2533 goto new_slab;
2534 }
2535
2536 /* must check again c->freelist in case of cpu migration or IRQ */
2537 freelist = c->freelist;
2538 if (freelist)
2539 goto load_freelist;
2540
2541 freelist = get_freelist(s, page);
2542
2543 if (!freelist) {
2544 c->page = NULL;
2545 stat(s, DEACTIVATE_BYPASS);
2546 goto new_slab;
2547 }
2548
2549 stat(s, ALLOC_REFILL);
2550
2551 load_freelist:
2552 /*
2553 * freelist is pointing to the list of objects to be used.
2554 * page is pointing to the page from which the objects are obtained.
2555 * That page must be frozen for per cpu allocations to work.
2556 */
2557 VM_BUG_ON(!c->page->frozen);
2558 c->freelist = get_freepointer(s, freelist);
2559 c->tid = next_tid(c->tid);
2560 return freelist;
2561
2562 new_slab:
2563
2564 if (c->partial) {
2565 page = c->page = c->partial;
2566 c->partial = page->next;
2567 stat(s, CPU_PARTIAL_ALLOC);
2568 c->freelist = NULL;
2569 goto redo;
2570 }
2571
2572 freelist = new_slab_objects(s, gfpflags, node, &c);
2573
2574 if (unlikely(!freelist)) {
2575 slab_out_of_memory(s, gfpflags, node);
2576 return NULL;
2577 }
2578
2579 page = c->page;
2580 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2581 goto load_freelist;
2582
2583 /* Only entered in the debug case */
2584 if (kmem_cache_debug(s) &&
2585 !alloc_debug_processing(s, page, freelist, addr))
2586 goto new_slab; /* Slab failed checks. Next slab needed */
2587
2588 deactivate_slab(s, page, get_freepointer(s, freelist));
2589 c->page = NULL;
2590 c->freelist = NULL;
2591 return freelist;
2592 }
2593
2594 /*
2595 * Another one that disabled interrupt and compensates for possible
2596 * cpu changes by refetching the per cpu area pointer.
2597 */
2598 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2599 unsigned long addr, struct kmem_cache_cpu *c)
2600 {
2601 void *p;
2602 unsigned long flags;
2603
2604 local_irq_save(flags);
2605 #ifdef CONFIG_PREEMPT
2606 /*
2607 * We may have been preempted and rescheduled on a different
2608 * cpu before disabling interrupts. Need to reload cpu area
2609 * pointer.
2610 */
2611 c = this_cpu_ptr(s->cpu_slab);
2612 #endif
2613
2614 p = ___slab_alloc(s, gfpflags, node, addr, c);
2615 local_irq_restore(flags);
2616 return p;
2617 }
2618
2619 /*
2620 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2621 * have the fastpath folded into their functions. So no function call
2622 * overhead for requests that can be satisfied on the fastpath.
2623 *
2624 * The fastpath works by first checking if the lockless freelist can be used.
2625 * If not then __slab_alloc is called for slow processing.
2626 *
2627 * Otherwise we can simply pick the next object from the lockless free list.
2628 */
2629 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2630 gfp_t gfpflags, int node, unsigned long addr)
2631 {
2632 void *object;
2633 struct kmem_cache_cpu *c;
2634 struct page *page;
2635 unsigned long tid;
2636
2637 s = slab_pre_alloc_hook(s, gfpflags);
2638 if (!s)
2639 return NULL;
2640 redo:
2641 /*
2642 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2643 * enabled. We may switch back and forth between cpus while
2644 * reading from one cpu area. That does not matter as long
2645 * as we end up on the original cpu again when doing the cmpxchg.
2646 *
2647 * We should guarantee that tid and kmem_cache are retrieved on
2648 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2649 * to check if it is matched or not.
2650 */
2651 do {
2652 tid = this_cpu_read(s->cpu_slab->tid);
2653 c = raw_cpu_ptr(s->cpu_slab);
2654 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2655 unlikely(tid != READ_ONCE(c->tid)));
2656
2657 /*
2658 * Irqless object alloc/free algorithm used here depends on sequence
2659 * of fetching cpu_slab's data. tid should be fetched before anything
2660 * on c to guarantee that object and page associated with previous tid
2661 * won't be used with current tid. If we fetch tid first, object and
2662 * page could be one associated with next tid and our alloc/free
2663 * request will be failed. In this case, we will retry. So, no problem.
2664 */
2665 barrier();
2666
2667 /*
2668 * The transaction ids are globally unique per cpu and per operation on
2669 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2670 * occurs on the right processor and that there was no operation on the
2671 * linked list in between.
2672 */
2673
2674 object = c->freelist;
2675 page = c->page;
2676 if (unlikely(!object || !node_match(page, node))) {
2677 object = __slab_alloc(s, gfpflags, node, addr, c);
2678 stat(s, ALLOC_SLOWPATH);
2679 } else {
2680 void *next_object = get_freepointer_safe(s, object);
2681
2682 /*
2683 * The cmpxchg will only match if there was no additional
2684 * operation and if we are on the right processor.
2685 *
2686 * The cmpxchg does the following atomically (without lock
2687 * semantics!)
2688 * 1. Relocate first pointer to the current per cpu area.
2689 * 2. Verify that tid and freelist have not been changed
2690 * 3. If they were not changed replace tid and freelist
2691 *
2692 * Since this is without lock semantics the protection is only
2693 * against code executing on this cpu *not* from access by
2694 * other cpus.
2695 */
2696 if (unlikely(!this_cpu_cmpxchg_double(
2697 s->cpu_slab->freelist, s->cpu_slab->tid,
2698 object, tid,
2699 next_object, next_tid(tid)))) {
2700
2701 note_cmpxchg_failure("slab_alloc", s, tid);
2702 goto redo;
2703 }
2704 prefetch_freepointer(s, next_object);
2705 stat(s, ALLOC_FASTPATH);
2706 }
2707
2708 if (unlikely(gfpflags & __GFP_ZERO) && object)
2709 memset(object, 0, s->object_size);
2710
2711 slab_post_alloc_hook(s, gfpflags, 1, &object);
2712
2713 return object;
2714 }
2715
2716 static __always_inline void *slab_alloc(struct kmem_cache *s,
2717 gfp_t gfpflags, unsigned long addr)
2718 {
2719 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2720 }
2721
2722 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2723 {
2724 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2725
2726 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2727 s->size, gfpflags);
2728
2729 return ret;
2730 }
2731 EXPORT_SYMBOL(kmem_cache_alloc);
2732
2733 #ifdef CONFIG_TRACING
2734 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2735 {
2736 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2737 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2738 kasan_kmalloc(s, ret, size, gfpflags);
2739 return ret;
2740 }
2741 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2742 #endif
2743
2744 #ifdef CONFIG_NUMA
2745 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2746 {
2747 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2748
2749 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2750 s->object_size, s->size, gfpflags, node);
2751
2752 return ret;
2753 }
2754 EXPORT_SYMBOL(kmem_cache_alloc_node);
2755
2756 #ifdef CONFIG_TRACING
2757 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2758 gfp_t gfpflags,
2759 int node, size_t size)
2760 {
2761 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2762
2763 trace_kmalloc_node(_RET_IP_, ret,
2764 size, s->size, gfpflags, node);
2765
2766 kasan_kmalloc(s, ret, size, gfpflags);
2767 return ret;
2768 }
2769 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2770 #endif
2771 #endif
2772
2773 /*
2774 * Slow path handling. This may still be called frequently since objects
2775 * have a longer lifetime than the cpu slabs in most processing loads.
2776 *
2777 * So we still attempt to reduce cache line usage. Just take the slab
2778 * lock and free the item. If there is no additional partial page
2779 * handling required then we can return immediately.
2780 */
2781 static void __slab_free(struct kmem_cache *s, struct page *page,
2782 void *head, void *tail, int cnt,
2783 unsigned long addr)
2784
2785 {
2786 void *prior;
2787 int was_frozen;
2788 struct page new;
2789 unsigned long counters;
2790 struct kmem_cache_node *n = NULL;
2791 unsigned long uninitialized_var(flags);
2792
2793 stat(s, FREE_SLOWPATH);
2794
2795 if (kmem_cache_debug(s) &&
2796 !free_debug_processing(s, page, head, tail, cnt, addr))
2797 return;
2798
2799 do {
2800 if (unlikely(n)) {
2801 spin_unlock_irqrestore(&n->list_lock, flags);
2802 n = NULL;
2803 }
2804 prior = page->freelist;
2805 counters = page->counters;
2806 set_freepointer(s, tail, prior);
2807 new.counters = counters;
2808 was_frozen = new.frozen;
2809 new.inuse -= cnt;
2810 if ((!new.inuse || !prior) && !was_frozen) {
2811
2812 if (kmem_cache_has_cpu_partial(s) && !prior) {
2813
2814 /*
2815 * Slab was on no list before and will be
2816 * partially empty
2817 * We can defer the list move and instead
2818 * freeze it.
2819 */
2820 new.frozen = 1;
2821
2822 } else { /* Needs to be taken off a list */
2823
2824 n = get_node(s, page_to_nid(page));
2825 /*
2826 * Speculatively acquire the list_lock.
2827 * If the cmpxchg does not succeed then we may
2828 * drop the list_lock without any processing.
2829 *
2830 * Otherwise the list_lock will synchronize with
2831 * other processors updating the list of slabs.
2832 */
2833 spin_lock_irqsave(&n->list_lock, flags);
2834
2835 }
2836 }
2837
2838 } while (!cmpxchg_double_slab(s, page,
2839 prior, counters,
2840 head, new.counters,
2841 "__slab_free"));
2842
2843 if (likely(!n)) {
2844
2845 /*
2846 * If we just froze the page then put it onto the
2847 * per cpu partial list.
2848 */
2849 if (new.frozen && !was_frozen) {
2850 put_cpu_partial(s, page, 1);
2851 stat(s, CPU_PARTIAL_FREE);
2852 }
2853 /*
2854 * The list lock was not taken therefore no list
2855 * activity can be necessary.
2856 */
2857 if (was_frozen)
2858 stat(s, FREE_FROZEN);
2859 return;
2860 }
2861
2862 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2863 goto slab_empty;
2864
2865 /*
2866 * Objects left in the slab. If it was not on the partial list before
2867 * then add it.
2868 */
2869 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2870 if (kmem_cache_debug(s))
2871 remove_full(s, n, page);
2872 add_partial(n, page, DEACTIVATE_TO_TAIL);
2873 stat(s, FREE_ADD_PARTIAL);
2874 }
2875 spin_unlock_irqrestore(&n->list_lock, flags);
2876 return;
2877
2878 slab_empty:
2879 if (prior) {
2880 /*
2881 * Slab on the partial list.
2882 */
2883 remove_partial(n, page);
2884 stat(s, FREE_REMOVE_PARTIAL);
2885 } else {
2886 /* Slab must be on the full list */
2887 remove_full(s, n, page);
2888 }
2889
2890 spin_unlock_irqrestore(&n->list_lock, flags);
2891 stat(s, FREE_SLAB);
2892 discard_slab(s, page);
2893 }
2894
2895 /*
2896 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2897 * can perform fastpath freeing without additional function calls.
2898 *
2899 * The fastpath is only possible if we are freeing to the current cpu slab
2900 * of this processor. This typically the case if we have just allocated
2901 * the item before.
2902 *
2903 * If fastpath is not possible then fall back to __slab_free where we deal
2904 * with all sorts of special processing.
2905 *
2906 * Bulk free of a freelist with several objects (all pointing to the
2907 * same page) possible by specifying head and tail ptr, plus objects
2908 * count (cnt). Bulk free indicated by tail pointer being set.
2909 */
2910 static __always_inline void do_slab_free(struct kmem_cache *s,
2911 struct page *page, void *head, void *tail,
2912 int cnt, unsigned long addr)
2913 {
2914 void *tail_obj = tail ? : head;
2915 struct kmem_cache_cpu *c;
2916 unsigned long tid;
2917 redo:
2918 /*
2919 * Determine the currently cpus per cpu slab.
2920 * The cpu may change afterward. However that does not matter since
2921 * data is retrieved via this pointer. If we are on the same cpu
2922 * during the cmpxchg then the free will succeed.
2923 */
2924 do {
2925 tid = this_cpu_read(s->cpu_slab->tid);
2926 c = raw_cpu_ptr(s->cpu_slab);
2927 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2928 unlikely(tid != READ_ONCE(c->tid)));
2929
2930 /* Same with comment on barrier() in slab_alloc_node() */
2931 barrier();
2932
2933 if (likely(page == c->page)) {
2934 set_freepointer(s, tail_obj, c->freelist);
2935
2936 if (unlikely(!this_cpu_cmpxchg_double(
2937 s->cpu_slab->freelist, s->cpu_slab->tid,
2938 c->freelist, tid,
2939 head, next_tid(tid)))) {
2940
2941 note_cmpxchg_failure("slab_free", s, tid);
2942 goto redo;
2943 }
2944 stat(s, FREE_FASTPATH);
2945 } else
2946 __slab_free(s, page, head, tail_obj, cnt, addr);
2947
2948 }
2949
2950 static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2951 void *head, void *tail, int cnt,
2952 unsigned long addr)
2953 {
2954 slab_free_freelist_hook(s, head, tail);
2955 /*
2956 * slab_free_freelist_hook() could have put the items into quarantine.
2957 * If so, no need to free them.
2958 */
2959 if (s->flags & SLAB_KASAN && !(s->flags & SLAB_DESTROY_BY_RCU))
2960 return;
2961 do_slab_free(s, page, head, tail, cnt, addr);
2962 }
2963
2964 #ifdef CONFIG_KASAN
2965 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
2966 {
2967 do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
2968 }
2969 #endif
2970
2971 void kmem_cache_free(struct kmem_cache *s, void *x)
2972 {
2973 s = cache_from_obj(s, x);
2974 if (!s)
2975 return;
2976 slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
2977 trace_kmem_cache_free(_RET_IP_, x);
2978 }
2979 EXPORT_SYMBOL(kmem_cache_free);
2980
2981 struct detached_freelist {
2982 struct page *page;
2983 void *tail;
2984 void *freelist;
2985 int cnt;
2986 struct kmem_cache *s;
2987 };
2988
2989 /*
2990 * This function progressively scans the array with free objects (with
2991 * a limited look ahead) and extract objects belonging to the same
2992 * page. It builds a detached freelist directly within the given
2993 * page/objects. This can happen without any need for
2994 * synchronization, because the objects are owned by running process.
2995 * The freelist is build up as a single linked list in the objects.
2996 * The idea is, that this detached freelist can then be bulk
2997 * transferred to the real freelist(s), but only requiring a single
2998 * synchronization primitive. Look ahead in the array is limited due
2999 * to performance reasons.
3000 */
3001 static inline
3002 int build_detached_freelist(struct kmem_cache *s, size_t size,
3003 void **p, struct detached_freelist *df)
3004 {
3005 size_t first_skipped_index = 0;
3006 int lookahead = 3;
3007 void *object;
3008 struct page *page;
3009
3010 /* Always re-init detached_freelist */
3011 df->page = NULL;
3012
3013 do {
3014 object = p[--size];
3015 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3016 } while (!object && size);
3017
3018 if (!object)
3019 return 0;
3020
3021 page = virt_to_head_page(object);
3022 if (!s) {
3023 /* Handle kalloc'ed objects */
3024 if (unlikely(!PageSlab(page))) {
3025 BUG_ON(!PageCompound(page));
3026 kfree_hook(object);
3027 __free_pages(page, compound_order(page));
3028 p[size] = NULL; /* mark object processed */
3029 return size;
3030 }
3031 /* Derive kmem_cache from object */
3032 df->s = page->slab_cache;
3033 } else {
3034 df->s = cache_from_obj(s, object); /* Support for memcg */
3035 }
3036
3037 /* Start new detached freelist */
3038 df->page = page;
3039 set_freepointer(df->s, object, NULL);
3040 df->tail = object;
3041 df->freelist = object;
3042 p[size] = NULL; /* mark object processed */
3043 df->cnt = 1;
3044
3045 while (size) {
3046 object = p[--size];
3047 if (!object)
3048 continue; /* Skip processed objects */
3049
3050 /* df->page is always set at this point */
3051 if (df->page == virt_to_head_page(object)) {
3052 /* Opportunity build freelist */
3053 set_freepointer(df->s, object, df->freelist);
3054 df->freelist = object;
3055 df->cnt++;
3056 p[size] = NULL; /* mark object processed */
3057
3058 continue;
3059 }
3060
3061 /* Limit look ahead search */
3062 if (!--lookahead)
3063 break;
3064
3065 if (!first_skipped_index)
3066 first_skipped_index = size + 1;
3067 }
3068
3069 return first_skipped_index;
3070 }
3071
3072 /* Note that interrupts must be enabled when calling this function. */
3073 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3074 {
3075 if (WARN_ON(!size))
3076 return;
3077
3078 do {
3079 struct detached_freelist df;
3080
3081 size = build_detached_freelist(s, size, p, &df);
3082 if (!df.page)
3083 continue;
3084
3085 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3086 } while (likely(size));
3087 }
3088 EXPORT_SYMBOL(kmem_cache_free_bulk);
3089
3090 /* Note that interrupts must be enabled when calling this function. */
3091 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3092 void **p)
3093 {
3094 struct kmem_cache_cpu *c;
3095 int i;
3096
3097 /* memcg and kmem_cache debug support */
3098 s = slab_pre_alloc_hook(s, flags);
3099 if (unlikely(!s))
3100 return false;
3101 /*
3102 * Drain objects in the per cpu slab, while disabling local
3103 * IRQs, which protects against PREEMPT and interrupts
3104 * handlers invoking normal fastpath.
3105 */
3106 local_irq_disable();
3107 c = this_cpu_ptr(s->cpu_slab);
3108
3109 for (i = 0; i < size; i++) {
3110 void *object = c->freelist;
3111
3112 if (unlikely(!object)) {
3113 /*
3114 * Invoking slow path likely have side-effect
3115 * of re-populating per CPU c->freelist
3116 */
3117 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3118 _RET_IP_, c);
3119 if (unlikely(!p[i]))
3120 goto error;
3121
3122 c = this_cpu_ptr(s->cpu_slab);
3123 continue; /* goto for-loop */
3124 }
3125 c->freelist = get_freepointer(s, object);
3126 p[i] = object;
3127 }
3128 c->tid = next_tid(c->tid);
3129 local_irq_enable();
3130
3131 /* Clear memory outside IRQ disabled fastpath loop */
3132 if (unlikely(flags & __GFP_ZERO)) {
3133 int j;
3134
3135 for (j = 0; j < i; j++)
3136 memset(p[j], 0, s->object_size);
3137 }
3138
3139 /* memcg and kmem_cache debug support */
3140 slab_post_alloc_hook(s, flags, size, p);
3141 return i;
3142 error:
3143 local_irq_enable();
3144 slab_post_alloc_hook(s, flags, i, p);
3145 __kmem_cache_free_bulk(s, i, p);
3146 return 0;
3147 }
3148 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3149
3150
3151 /*
3152 * Object placement in a slab is made very easy because we always start at
3153 * offset 0. If we tune the size of the object to the alignment then we can
3154 * get the required alignment by putting one properly sized object after
3155 * another.
3156 *
3157 * Notice that the allocation order determines the sizes of the per cpu
3158 * caches. Each processor has always one slab available for allocations.
3159 * Increasing the allocation order reduces the number of times that slabs
3160 * must be moved on and off the partial lists and is therefore a factor in
3161 * locking overhead.
3162 */
3163
3164 /*
3165 * Mininum / Maximum order of slab pages. This influences locking overhead
3166 * and slab fragmentation. A higher order reduces the number of partial slabs
3167 * and increases the number of allocations possible without having to
3168 * take the list_lock.
3169 */
3170 static int slub_min_order;
3171 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3172 static int slub_min_objects;
3173
3174 /*
3175 * Calculate the order of allocation given an slab object size.
3176 *
3177 * The order of allocation has significant impact on performance and other
3178 * system components. Generally order 0 allocations should be preferred since
3179 * order 0 does not cause fragmentation in the page allocator. Larger objects
3180 * be problematic to put into order 0 slabs because there may be too much
3181 * unused space left. We go to a higher order if more than 1/16th of the slab
3182 * would be wasted.
3183 *
3184 * In order to reach satisfactory performance we must ensure that a minimum
3185 * number of objects is in one slab. Otherwise we may generate too much
3186 * activity on the partial lists which requires taking the list_lock. This is
3187 * less a concern for large slabs though which are rarely used.
3188 *
3189 * slub_max_order specifies the order where we begin to stop considering the
3190 * number of objects in a slab as critical. If we reach slub_max_order then
3191 * we try to keep the page order as low as possible. So we accept more waste
3192 * of space in favor of a small page order.
3193 *
3194 * Higher order allocations also allow the placement of more objects in a
3195 * slab and thereby reduce object handling overhead. If the user has
3196 * requested a higher mininum order then we start with that one instead of
3197 * the smallest order which will fit the object.
3198 */
3199 static inline int slab_order(int size, int min_objects,
3200 int max_order, int fract_leftover, int reserved)
3201 {
3202 int order;
3203 int rem;
3204 int min_order = slub_min_order;
3205
3206 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
3207 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3208
3209 for (order = max(min_order, get_order(min_objects * size + reserved));
3210 order <= max_order; order++) {
3211
3212 unsigned long slab_size = PAGE_SIZE << order;
3213
3214 rem = (slab_size - reserved) % size;
3215
3216 if (rem <= slab_size / fract_leftover)
3217 break;
3218 }
3219
3220 return order;
3221 }
3222
3223 static inline int calculate_order(int size, int reserved)
3224 {
3225 int order;
3226 int min_objects;
3227 int fraction;
3228 int max_objects;
3229
3230 /*
3231 * Attempt to find best configuration for a slab. This
3232 * works by first attempting to generate a layout with
3233 * the best configuration and backing off gradually.
3234 *
3235 * First we increase the acceptable waste in a slab. Then
3236 * we reduce the minimum objects required in a slab.
3237 */
3238 min_objects = slub_min_objects;
3239 if (!min_objects)
3240 min_objects = 4 * (fls(nr_cpu_ids) + 1);
3241 max_objects = order_objects(slub_max_order, size, reserved);
3242 min_objects = min(min_objects, max_objects);
3243
3244 while (min_objects > 1) {
3245 fraction = 16;
3246 while (fraction >= 4) {
3247 order = slab_order(size, min_objects,
3248 slub_max_order, fraction, reserved);
3249 if (order <= slub_max_order)
3250 return order;
3251 fraction /= 2;
3252 }
3253 min_objects--;
3254 }
3255
3256 /*
3257 * We were unable to place multiple objects in a slab. Now
3258 * lets see if we can place a single object there.
3259 */
3260 order = slab_order(size, 1, slub_max_order, 1, reserved);
3261 if (order <= slub_max_order)
3262 return order;
3263
3264 /*
3265 * Doh this slab cannot be placed using slub_max_order.
3266 */
3267 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
3268 if (order < MAX_ORDER)
3269 return order;
3270 return -ENOSYS;
3271 }
3272
3273 static void
3274 init_kmem_cache_node(struct kmem_cache_node *n)
3275 {
3276 n->nr_partial = 0;
3277 spin_lock_init(&n->list_lock);
3278 INIT_LIST_HEAD(&n->partial);
3279 #ifdef CONFIG_SLUB_DEBUG
3280 atomic_long_set(&n->nr_slabs, 0);
3281 atomic_long_set(&n->total_objects, 0);
3282 INIT_LIST_HEAD(&n->full);
3283 #endif
3284 }
3285
3286 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3287 {
3288 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3289 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3290
3291 /*
3292 * Must align to double word boundary for the double cmpxchg
3293 * instructions to work; see __pcpu_double_call_return_bool().
3294 */
3295 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3296 2 * sizeof(void *));
3297
3298 if (!s->cpu_slab)
3299 return 0;
3300
3301 init_kmem_cache_cpus(s);
3302
3303 return 1;
3304 }
3305
3306 static struct kmem_cache *kmem_cache_node;
3307
3308 /*
3309 * No kmalloc_node yet so do it by hand. We know that this is the first
3310 * slab on the node for this slabcache. There are no concurrent accesses
3311 * possible.
3312 *
3313 * Note that this function only works on the kmem_cache_node
3314 * when allocating for the kmem_cache_node. This is used for bootstrapping
3315 * memory on a fresh node that has no slab structures yet.
3316 */
3317 static void early_kmem_cache_node_alloc(int node)
3318 {
3319 struct page *page;
3320 struct kmem_cache_node *n;
3321
3322 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3323
3324 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3325
3326 BUG_ON(!page);
3327 if (page_to_nid(page) != node) {
3328 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3329 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3330 }
3331
3332 n = page->freelist;
3333 BUG_ON(!n);
3334 page->freelist = get_freepointer(kmem_cache_node, n);
3335 page->inuse = 1;
3336 page->frozen = 0;
3337 kmem_cache_node->node[node] = n;
3338 #ifdef CONFIG_SLUB_DEBUG
3339 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3340 init_tracking(kmem_cache_node, n);
3341 #endif
3342 kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3343 GFP_KERNEL);
3344 init_kmem_cache_node(n);
3345 inc_slabs_node(kmem_cache_node, node, page->objects);
3346
3347 /*
3348 * No locks need to be taken here as it has just been
3349 * initialized and there is no concurrent access.
3350 */
3351 __add_partial(n, page, DEACTIVATE_TO_HEAD);
3352 }
3353
3354 static void free_kmem_cache_nodes(struct kmem_cache *s)
3355 {
3356 int node;
3357 struct kmem_cache_node *n;
3358
3359 for_each_kmem_cache_node(s, node, n) {
3360 kmem_cache_free(kmem_cache_node, n);
3361 s->node[node] = NULL;
3362 }
3363 }
3364
3365 void __kmem_cache_release(struct kmem_cache *s)
3366 {
3367 cache_random_seq_destroy(s);
3368 free_percpu(s->cpu_slab);
3369 free_kmem_cache_nodes(s);
3370 }
3371
3372 static int init_kmem_cache_nodes(struct kmem_cache *s)
3373 {
3374 int node;
3375
3376 for_each_node_state(node, N_NORMAL_MEMORY) {
3377 struct kmem_cache_node *n;
3378
3379 if (slab_state == DOWN) {
3380 early_kmem_cache_node_alloc(node);
3381 continue;
3382 }
3383 n = kmem_cache_alloc_node(kmem_cache_node,
3384 GFP_KERNEL, node);
3385
3386 if (!n) {
3387 free_kmem_cache_nodes(s);
3388 return 0;
3389 }
3390
3391 s->node[node] = n;
3392 init_kmem_cache_node(n);
3393 }
3394 return 1;
3395 }
3396
3397 static void set_min_partial(struct kmem_cache *s, unsigned long min)
3398 {
3399 if (min < MIN_PARTIAL)
3400 min = MIN_PARTIAL;
3401 else if (min > MAX_PARTIAL)
3402 min = MAX_PARTIAL;
3403 s->min_partial = min;
3404 }
3405
3406 /*
3407 * calculate_sizes() determines the order and the distribution of data within
3408 * a slab object.
3409 */
3410 static int calculate_sizes(struct kmem_cache *s, int forced_order)
3411 {
3412 unsigned long flags = s->flags;
3413 size_t size = s->object_size;
3414 int order;
3415
3416 /*
3417 * Round up object size to the next word boundary. We can only
3418 * place the free pointer at word boundaries and this determines
3419 * the possible location of the free pointer.
3420 */
3421 size = ALIGN(size, sizeof(void *));
3422
3423 #ifdef CONFIG_SLUB_DEBUG
3424 /*
3425 * Determine if we can poison the object itself. If the user of
3426 * the slab may touch the object after free or before allocation
3427 * then we should never poison the object itself.
3428 */
3429 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
3430 !s->ctor)
3431 s->flags |= __OBJECT_POISON;
3432 else
3433 s->flags &= ~__OBJECT_POISON;
3434
3435
3436 /*
3437 * If we are Redzoning then check if there is some space between the
3438 * end of the object and the free pointer. If not then add an
3439 * additional word to have some bytes to store Redzone information.
3440 */
3441 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3442 size += sizeof(void *);
3443 #endif
3444
3445 /*
3446 * With that we have determined the number of bytes in actual use
3447 * by the object. This is the potential offset to the free pointer.
3448 */
3449 s->inuse = size;
3450
3451 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
3452 s->ctor)) {
3453 /*
3454 * Relocate free pointer after the object if it is not
3455 * permitted to overwrite the first word of the object on
3456 * kmem_cache_free.
3457 *
3458 * This is the case if we do RCU, have a constructor or
3459 * destructor or are poisoning the objects.
3460 */
3461 s->offset = size;
3462 size += sizeof(void *);
3463 }
3464
3465 #ifdef CONFIG_SLUB_DEBUG
3466 if (flags & SLAB_STORE_USER)
3467 /*
3468 * Need to store information about allocs and frees after
3469 * the object.
3470 */
3471 size += 2 * sizeof(struct track);
3472 #endif
3473
3474 kasan_cache_create(s, &size, &s->flags);
3475 #ifdef CONFIG_SLUB_DEBUG
3476 if (flags & SLAB_RED_ZONE) {
3477 /*
3478 * Add some empty padding so that we can catch
3479 * overwrites from earlier objects rather than let
3480 * tracking information or the free pointer be
3481 * corrupted if a user writes before the start
3482 * of the object.
3483 */
3484 size += sizeof(void *);
3485
3486 s->red_left_pad = sizeof(void *);
3487 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3488 size += s->red_left_pad;
3489 }
3490 #endif
3491
3492 /*
3493 * SLUB stores one object immediately after another beginning from
3494 * offset 0. In order to align the objects we have to simply size
3495 * each object to conform to the alignment.
3496 */
3497 size = ALIGN(size, s->align);
3498 s->size = size;
3499 if (forced_order >= 0)
3500 order = forced_order;
3501 else
3502 order = calculate_order(size, s->reserved);
3503
3504 if (order < 0)
3505 return 0;
3506
3507 s->allocflags = 0;
3508 if (order)
3509 s->allocflags |= __GFP_COMP;
3510
3511 if (s->flags & SLAB_CACHE_DMA)
3512 s->allocflags |= GFP_DMA;
3513
3514 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3515 s->allocflags |= __GFP_RECLAIMABLE;
3516
3517 /*
3518 * Determine the number of objects per slab
3519 */
3520 s->oo = oo_make(order, size, s->reserved);
3521 s->min = oo_make(get_order(size), size, s->reserved);
3522 if (oo_objects(s->oo) > oo_objects(s->max))
3523 s->max = s->oo;
3524
3525 return !!oo_objects(s->oo);
3526 }
3527
3528 static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3529 {
3530 s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3531 s->reserved = 0;
3532
3533 if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3534 s->reserved = sizeof(struct rcu_head);
3535
3536 if (!calculate_sizes(s, -1))
3537 goto error;
3538 if (disable_higher_order_debug) {
3539 /*
3540 * Disable debugging flags that store metadata if the min slab
3541 * order increased.
3542 */
3543 if (get_order(s->size) > get_order(s->object_size)) {
3544 s->flags &= ~DEBUG_METADATA_FLAGS;
3545 s->offset = 0;
3546 if (!calculate_sizes(s, -1))
3547 goto error;
3548 }
3549 }
3550
3551 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3552 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3553 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3554 /* Enable fast mode */
3555 s->flags |= __CMPXCHG_DOUBLE;
3556 #endif
3557
3558 /*
3559 * The larger the object size is, the more pages we want on the partial
3560 * list to avoid pounding the page allocator excessively.
3561 */
3562 set_min_partial(s, ilog2(s->size) / 2);
3563
3564 /*
3565 * cpu_partial determined the maximum number of objects kept in the
3566 * per cpu partial lists of a processor.
3567 *
3568 * Per cpu partial lists mainly contain slabs that just have one
3569 * object freed. If they are used for allocation then they can be
3570 * filled up again with minimal effort. The slab will never hit the
3571 * per node partial lists and therefore no locking will be required.
3572 *
3573 * This setting also determines
3574 *
3575 * A) The number of objects from per cpu partial slabs dumped to the
3576 * per node list when we reach the limit.
3577 * B) The number of objects in cpu partial slabs to extract from the
3578 * per node list when we run out of per cpu objects. We only fetch
3579 * 50% to keep some capacity around for frees.
3580 */
3581 if (!kmem_cache_has_cpu_partial(s))
3582 s->cpu_partial = 0;
3583 else if (s->size >= PAGE_SIZE)
3584 s->cpu_partial = 2;
3585 else if (s->size >= 1024)
3586 s->cpu_partial = 6;
3587 else if (s->size >= 256)
3588 s->cpu_partial = 13;
3589 else
3590 s->cpu_partial = 30;
3591
3592 #ifdef CONFIG_NUMA
3593 s->remote_node_defrag_ratio = 1000;
3594 #endif
3595
3596 /* Initialize the pre-computed randomized freelist if slab is up */
3597 if (slab_state >= UP) {
3598 if (init_cache_random_seq(s))
3599 goto error;
3600 }
3601
3602 if (!init_kmem_cache_nodes(s))
3603 goto error;
3604
3605 if (alloc_kmem_cache_cpus(s))
3606 return 0;
3607
3608 free_kmem_cache_nodes(s);
3609 error:
3610 if (flags & SLAB_PANIC)
3611 panic("Cannot create slab %s size=%lu realsize=%u order=%u offset=%u flags=%lx\n",
3612 s->name, (unsigned long)s->size, s->size,
3613 oo_order(s->oo), s->offset, flags);
3614 return -EINVAL;
3615 }
3616
3617 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3618 const char *text)
3619 {
3620 #ifdef CONFIG_SLUB_DEBUG
3621 void *addr = page_address(page);
3622 void *p;
3623 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3624 sizeof(long), GFP_ATOMIC);
3625 if (!map)
3626 return;
3627 slab_err(s, page, text, s->name);
3628 slab_lock(page);
3629
3630 get_map(s, page, map);
3631 for_each_object(p, s, addr, page->objects) {
3632
3633 if (!test_bit(slab_index(p, s, addr), map)) {
3634 pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3635 print_tracking(s, p);
3636 }
3637 }
3638 slab_unlock(page);
3639 kfree(map);
3640 #endif
3641 }
3642
3643 /*
3644 * Attempt to free all partial slabs on a node.
3645 * This is called from __kmem_cache_shutdown(). We must take list_lock
3646 * because sysfs file might still access partial list after the shutdowning.
3647 */
3648 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3649 {
3650 LIST_HEAD(discard);
3651 struct page *page, *h;
3652
3653 BUG_ON(irqs_disabled());
3654 spin_lock_irq(&n->list_lock);
3655 list_for_each_entry_safe(page, h, &n->partial, lru) {
3656 if (!page->inuse) {
3657 remove_partial(n, page);
3658 list_add(&page->lru, &discard);
3659 } else {
3660 list_slab_objects(s, page,
3661 "Objects remaining in %s on __kmem_cache_shutdown()");
3662 }
3663 }
3664 spin_unlock_irq(&n->list_lock);
3665
3666 list_for_each_entry_safe(page, h, &discard, lru)
3667 discard_slab(s, page);
3668 }
3669
3670 /*
3671 * Release all resources used by a slab cache.
3672 */
3673 int __kmem_cache_shutdown(struct kmem_cache *s)
3674 {
3675 int node;
3676 struct kmem_cache_node *n;
3677
3678 flush_all(s);
3679 /* Attempt to free all objects */
3680 for_each_kmem_cache_node(s, node, n) {
3681 free_partial(s, n);
3682 if (n->nr_partial || slabs_node(s, node))
3683 return 1;
3684 }
3685 return 0;
3686 }
3687
3688 /********************************************************************
3689 * Kmalloc subsystem
3690 *******************************************************************/
3691
3692 static int __init setup_slub_min_order(char *str)
3693 {
3694 get_option(&str, &slub_min_order);
3695
3696 return 1;
3697 }
3698
3699 __setup("slub_min_order=", setup_slub_min_order);
3700
3701 static int __init setup_slub_max_order(char *str)
3702 {
3703 get_option(&str, &slub_max_order);
3704 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3705
3706 return 1;
3707 }
3708
3709 __setup("slub_max_order=", setup_slub_max_order);
3710
3711 static int __init setup_slub_min_objects(char *str)
3712 {
3713 get_option(&str, &slub_min_objects);
3714
3715 return 1;
3716 }
3717
3718 __setup("slub_min_objects=", setup_slub_min_objects);
3719
3720 void *__kmalloc(size_t size, gfp_t flags)
3721 {
3722 struct kmem_cache *s;
3723 void *ret;
3724
3725 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3726 return kmalloc_large(size, flags);
3727
3728 s = kmalloc_slab(size, flags);
3729
3730 if (unlikely(ZERO_OR_NULL_PTR(s)))
3731 return s;
3732
3733 ret = slab_alloc(s, flags, _RET_IP_);
3734
3735 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3736
3737 kasan_kmalloc(s, ret, size, flags);
3738
3739 return ret;
3740 }
3741 EXPORT_SYMBOL(__kmalloc);
3742
3743 #ifdef CONFIG_NUMA
3744 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3745 {
3746 struct page *page;
3747 void *ptr = NULL;
3748
3749 flags |= __GFP_COMP | __GFP_NOTRACK;
3750 page = alloc_pages_node(node, flags, get_order(size));
3751 if (page)
3752 ptr = page_address(page);
3753
3754 kmalloc_large_node_hook(ptr, size, flags);
3755 return ptr;
3756 }
3757
3758 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3759 {
3760 struct kmem_cache *s;
3761 void *ret;
3762
3763 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3764 ret = kmalloc_large_node(size, flags, node);
3765
3766 trace_kmalloc_node(_RET_IP_, ret,
3767 size, PAGE_SIZE << get_order(size),
3768 flags, node);
3769
3770 return ret;
3771 }
3772
3773 s = kmalloc_slab(size, flags);
3774
3775 if (unlikely(ZERO_OR_NULL_PTR(s)))
3776 return s;
3777
3778 ret = slab_alloc_node(s, flags, node, _RET_IP_);
3779
3780 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3781
3782 kasan_kmalloc(s, ret, size, flags);
3783
3784 return ret;
3785 }
3786 EXPORT_SYMBOL(__kmalloc_node);
3787 #endif
3788
3789 #ifdef CONFIG_HARDENED_USERCOPY
3790 /*
3791 * Rejects objects that are incorrectly sized.
3792 *
3793 * Returns NULL if check passes, otherwise const char * to name of cache
3794 * to indicate an error.
3795 */
3796 const char *__check_heap_object(const void *ptr, unsigned long n,
3797 struct page *page)
3798 {
3799 struct kmem_cache *s;
3800 unsigned long offset;
3801 size_t object_size;
3802
3803 /* Find object and usable object size. */
3804 s = page->slab_cache;
3805 object_size = slab_ksize(s);
3806
3807 /* Reject impossible pointers. */
3808 if (ptr < page_address(page))
3809 return s->name;
3810
3811 /* Find offset within object. */
3812 offset = (ptr - page_address(page)) % s->size;
3813
3814 /* Adjust for redzone and reject if within the redzone. */
3815 if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
3816 if (offset < s->red_left_pad)
3817 return s->name;
3818 offset -= s->red_left_pad;
3819 }
3820
3821 /* Allow address range falling entirely within object size. */
3822 if (offset <= object_size && n <= object_size - offset)
3823 return NULL;
3824
3825 return s->name;
3826 }
3827 #endif /* CONFIG_HARDENED_USERCOPY */
3828
3829 static size_t __ksize(const void *object)
3830 {
3831 struct page *page;
3832
3833 if (unlikely(object == ZERO_SIZE_PTR))
3834 return 0;
3835
3836 page = virt_to_head_page(object);
3837
3838 if (unlikely(!PageSlab(page))) {
3839 WARN_ON(!PageCompound(page));
3840 return PAGE_SIZE << compound_order(page);
3841 }
3842
3843 return slab_ksize(page->slab_cache);
3844 }
3845
3846 size_t ksize(const void *object)
3847 {
3848 size_t size = __ksize(object);
3849 /* We assume that ksize callers could use whole allocated area,
3850 * so we need to unpoison this area.
3851 */
3852 kasan_unpoison_shadow(object, size);
3853 return size;
3854 }
3855 EXPORT_SYMBOL(ksize);
3856
3857 void kfree(const void *x)
3858 {
3859 struct page *page;
3860 void *object = (void *)x;
3861
3862 trace_kfree(_RET_IP_, x);
3863
3864 if (unlikely(ZERO_OR_NULL_PTR(x)))
3865 return;
3866
3867 page = virt_to_head_page(x);
3868 if (unlikely(!PageSlab(page))) {
3869 BUG_ON(!PageCompound(page));
3870 kfree_hook(x);
3871 __free_pages(page, compound_order(page));
3872 return;
3873 }
3874 slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3875 }
3876 EXPORT_SYMBOL(kfree);
3877
3878 #define SHRINK_PROMOTE_MAX 32
3879
3880 /*
3881 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3882 * up most to the head of the partial lists. New allocations will then
3883 * fill those up and thus they can be removed from the partial lists.
3884 *
3885 * The slabs with the least items are placed last. This results in them
3886 * being allocated from last increasing the chance that the last objects
3887 * are freed in them.
3888 */
3889 int __kmem_cache_shrink(struct kmem_cache *s)
3890 {
3891 int node;
3892 int i;
3893 struct kmem_cache_node *n;
3894 struct page *page;
3895 struct page *t;
3896 struct list_head discard;
3897 struct list_head promote[SHRINK_PROMOTE_MAX];
3898 unsigned long flags;
3899 int ret = 0;
3900
3901 flush_all(s);
3902 for_each_kmem_cache_node(s, node, n) {
3903 INIT_LIST_HEAD(&discard);
3904 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3905 INIT_LIST_HEAD(promote + i);
3906
3907 spin_lock_irqsave(&n->list_lock, flags);
3908
3909 /*
3910 * Build lists of slabs to discard or promote.
3911 *
3912 * Note that concurrent frees may occur while we hold the
3913 * list_lock. page->inuse here is the upper limit.
3914 */
3915 list_for_each_entry_safe(page, t, &n->partial, lru) {
3916 int free = page->objects - page->inuse;
3917
3918 /* Do not reread page->inuse */
3919 barrier();
3920
3921 /* We do not keep full slabs on the list */
3922 BUG_ON(free <= 0);
3923
3924 if (free == page->objects) {
3925 list_move(&page->lru, &discard);
3926 n->nr_partial--;
3927 } else if (free <= SHRINK_PROMOTE_MAX)
3928 list_move(&page->lru, promote + free - 1);
3929 }
3930
3931 /*
3932 * Promote the slabs filled up most to the head of the
3933 * partial list.
3934 */
3935 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
3936 list_splice(promote + i, &n->partial);
3937
3938 spin_unlock_irqrestore(&n->list_lock, flags);
3939
3940 /* Release empty slabs */
3941 list_for_each_entry_safe(page, t, &discard, lru)
3942 discard_slab(s, page);
3943
3944 if (slabs_node(s, node))
3945 ret = 1;
3946 }
3947
3948 return ret;
3949 }
3950
3951 static int slab_mem_going_offline_callback(void *arg)
3952 {
3953 struct kmem_cache *s;
3954
3955 mutex_lock(&slab_mutex);
3956 list_for_each_entry(s, &slab_caches, list)
3957 __kmem_cache_shrink(s);
3958 mutex_unlock(&slab_mutex);
3959
3960 return 0;
3961 }
3962
3963 static void slab_mem_offline_callback(void *arg)
3964 {
3965 struct kmem_cache_node *n;
3966 struct kmem_cache *s;
3967 struct memory_notify *marg = arg;
3968 int offline_node;
3969
3970 offline_node = marg->status_change_nid_normal;
3971
3972 /*
3973 * If the node still has available memory. we need kmem_cache_node
3974 * for it yet.
3975 */
3976 if (offline_node < 0)
3977 return;
3978
3979 mutex_lock(&slab_mutex);
3980 list_for_each_entry(s, &slab_caches, list) {
3981 n = get_node(s, offline_node);
3982 if (n) {
3983 /*
3984 * if n->nr_slabs > 0, slabs still exist on the node
3985 * that is going down. We were unable to free them,
3986 * and offline_pages() function shouldn't call this
3987 * callback. So, we must fail.
3988 */
3989 BUG_ON(slabs_node(s, offline_node));
3990
3991 s->node[offline_node] = NULL;
3992 kmem_cache_free(kmem_cache_node, n);
3993 }
3994 }
3995 mutex_unlock(&slab_mutex);
3996 }
3997
3998 static int slab_mem_going_online_callback(void *arg)
3999 {
4000 struct kmem_cache_node *n;
4001 struct kmem_cache *s;
4002 struct memory_notify *marg = arg;
4003 int nid = marg->status_change_nid_normal;
4004 int ret = 0;
4005
4006 /*
4007 * If the node's memory is already available, then kmem_cache_node is
4008 * already created. Nothing to do.
4009 */
4010 if (nid < 0)
4011 return 0;
4012
4013 /*
4014 * We are bringing a node online. No memory is available yet. We must
4015 * allocate a kmem_cache_node structure in order to bring the node
4016 * online.
4017 */
4018 mutex_lock(&slab_mutex);
4019 list_for_each_entry(s, &slab_caches, list) {
4020 /*
4021 * XXX: kmem_cache_alloc_node will fallback to other nodes
4022 * since memory is not yet available from the node that
4023 * is brought up.
4024 */
4025 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4026 if (!n) {
4027 ret = -ENOMEM;
4028 goto out;
4029 }
4030 init_kmem_cache_node(n);
4031 s->node[nid] = n;
4032 }
4033 out:
4034 mutex_unlock(&slab_mutex);
4035 return ret;
4036 }
4037
4038 static int slab_memory_callback(struct notifier_block *self,
4039 unsigned long action, void *arg)
4040 {
4041 int ret = 0;
4042
4043 switch (action) {
4044 case MEM_GOING_ONLINE:
4045 ret = slab_mem_going_online_callback(arg);
4046 break;
4047 case MEM_GOING_OFFLINE:
4048 ret = slab_mem_going_offline_callback(arg);
4049 break;
4050 case MEM_OFFLINE:
4051 case MEM_CANCEL_ONLINE:
4052 slab_mem_offline_callback(arg);
4053 break;
4054 case MEM_ONLINE:
4055 case MEM_CANCEL_OFFLINE:
4056 break;
4057 }
4058 if (ret)
4059 ret = notifier_from_errno(ret);
4060 else
4061 ret = NOTIFY_OK;
4062 return ret;
4063 }
4064
4065 static struct notifier_block slab_memory_callback_nb = {
4066 .notifier_call = slab_memory_callback,
4067 .priority = SLAB_CALLBACK_PRI,
4068 };
4069
4070 /********************************************************************
4071 * Basic setup of slabs
4072 *******************************************************************/
4073
4074 /*
4075 * Used for early kmem_cache structures that were allocated using
4076 * the page allocator. Allocate them properly then fix up the pointers
4077 * that may be pointing to the wrong kmem_cache structure.
4078 */
4079
4080 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4081 {
4082 int node;
4083 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4084 struct kmem_cache_node *n;
4085
4086 memcpy(s, static_cache, kmem_cache->object_size);
4087
4088 /*
4089 * This runs very early, and only the boot processor is supposed to be
4090 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4091 * IPIs around.
4092 */
4093 __flush_cpu_slab(s, smp_processor_id());
4094 for_each_kmem_cache_node(s, node, n) {
4095 struct page *p;
4096
4097 list_for_each_entry(p, &n->partial, lru)
4098 p->slab_cache = s;
4099
4100 #ifdef CONFIG_SLUB_DEBUG
4101 list_for_each_entry(p, &n->full, lru)
4102 p->slab_cache = s;
4103 #endif
4104 }
4105 slab_init_memcg_params(s);
4106 list_add(&s->list, &slab_caches);
4107 return s;
4108 }
4109
4110 void __init kmem_cache_init(void)
4111 {
4112 static __initdata struct kmem_cache boot_kmem_cache,
4113 boot_kmem_cache_node;
4114
4115 if (debug_guardpage_minorder())
4116 slub_max_order = 0;
4117
4118 kmem_cache_node = &boot_kmem_cache_node;
4119 kmem_cache = &boot_kmem_cache;
4120
4121 create_boot_cache(kmem_cache_node, "kmem_cache_node",
4122 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
4123
4124 register_hotmemory_notifier(&slab_memory_callback_nb);
4125
4126 /* Able to allocate the per node structures */
4127 slab_state = PARTIAL;
4128
4129 create_boot_cache(kmem_cache, "kmem_cache",
4130 offsetof(struct kmem_cache, node) +
4131 nr_node_ids * sizeof(struct kmem_cache_node *),
4132 SLAB_HWCACHE_ALIGN);
4133
4134 kmem_cache = bootstrap(&boot_kmem_cache);
4135
4136 /*
4137 * Allocate kmem_cache_node properly from the kmem_cache slab.
4138 * kmem_cache_node is separately allocated so no need to
4139 * update any list pointers.
4140 */
4141 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4142
4143 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4144 setup_kmalloc_cache_index_table();
4145 create_kmalloc_caches(0);
4146
4147 /* Setup random freelists for each cache */
4148 init_freelist_randomization();
4149
4150 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4151 slub_cpu_dead);
4152
4153 pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
4154 cache_line_size(),
4155 slub_min_order, slub_max_order, slub_min_objects,
4156 nr_cpu_ids, nr_node_ids);
4157 }
4158
4159 void __init kmem_cache_init_late(void)
4160 {
4161 }
4162
4163 struct kmem_cache *
4164 __kmem_cache_alias(const char *name, size_t size, size_t align,
4165 unsigned long flags, void (*ctor)(void *))
4166 {
4167 struct kmem_cache *s, *c;
4168
4169 s = find_mergeable(size, align, flags, name, ctor);
4170 if (s) {
4171 s->refcount++;
4172
4173 /*
4174 * Adjust the object sizes so that we clear
4175 * the complete object on kzalloc.
4176 */
4177 s->object_size = max(s->object_size, (int)size);
4178 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
4179
4180 for_each_memcg_cache(c, s) {
4181 c->object_size = s->object_size;
4182 c->inuse = max_t(int, c->inuse,
4183 ALIGN(size, sizeof(void *)));
4184 }
4185
4186 if (sysfs_slab_alias(s, name)) {
4187 s->refcount--;
4188 s = NULL;
4189 }
4190 }
4191
4192 return s;
4193 }
4194
4195 int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
4196 {
4197 int err;
4198
4199 err = kmem_cache_open(s, flags);
4200 if (err)
4201 return err;
4202
4203 /* Mutex is not taken during early boot */
4204 if (slab_state <= UP)
4205 return 0;
4206
4207 memcg_propagate_slab_attrs(s);
4208 err = sysfs_slab_add(s);
4209 if (err)
4210 __kmem_cache_release(s);
4211
4212 return err;
4213 }
4214
4215 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4216 {
4217 struct kmem_cache *s;
4218 void *ret;
4219
4220 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4221 return kmalloc_large(size, gfpflags);
4222
4223 s = kmalloc_slab(size, gfpflags);
4224
4225 if (unlikely(ZERO_OR_NULL_PTR(s)))
4226 return s;
4227
4228 ret = slab_alloc(s, gfpflags, caller);
4229
4230 /* Honor the call site pointer we received. */
4231 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4232
4233 return ret;
4234 }
4235
4236 #ifdef CONFIG_NUMA
4237 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4238 int node, unsigned long caller)
4239 {
4240 struct kmem_cache *s;
4241 void *ret;
4242
4243 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4244 ret = kmalloc_large_node(size, gfpflags, node);
4245
4246 trace_kmalloc_node(caller, ret,
4247 size, PAGE_SIZE << get_order(size),
4248 gfpflags, node);
4249
4250 return ret;
4251 }
4252
4253 s = kmalloc_slab(size, gfpflags);
4254
4255 if (unlikely(ZERO_OR_NULL_PTR(s)))
4256 return s;
4257
4258 ret = slab_alloc_node(s, gfpflags, node, caller);
4259
4260 /* Honor the call site pointer we received. */
4261 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4262
4263 return ret;
4264 }
4265 #endif
4266
4267 #ifdef CONFIG_SYSFS
4268 static int count_inuse(struct page *page)
4269 {
4270 return page->inuse;
4271 }
4272
4273 static int count_total(struct page *page)
4274 {
4275 return page->objects;
4276 }
4277 #endif
4278
4279 #ifdef CONFIG_SLUB_DEBUG
4280 static int validate_slab(struct kmem_cache *s, struct page *page,
4281 unsigned long *map)
4282 {
4283 void *p;
4284 void *addr = page_address(page);
4285
4286 if (!check_slab(s, page) ||
4287 !on_freelist(s, page, NULL))
4288 return 0;
4289
4290 /* Now we know that a valid freelist exists */
4291 bitmap_zero(map, page->objects);
4292
4293 get_map(s, page, map);
4294 for_each_object(p, s, addr, page->objects) {
4295 if (test_bit(slab_index(p, s, addr), map))
4296 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4297 return 0;
4298 }
4299
4300 for_each_object(p, s, addr, page->objects)
4301 if (!test_bit(slab_index(p, s, addr), map))
4302 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4303 return 0;
4304 return 1;
4305 }
4306
4307 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4308 unsigned long *map)
4309 {
4310 slab_lock(page);
4311 validate_slab(s, page, map);
4312 slab_unlock(page);
4313 }
4314
4315 static int validate_slab_node(struct kmem_cache *s,
4316 struct kmem_cache_node *n, unsigned long *map)
4317 {
4318 unsigned long count = 0;
4319 struct page *page;
4320 unsigned long flags;
4321
4322 spin_lock_irqsave(&n->list_lock, flags);
4323
4324 list_for_each_entry(page, &n->partial, lru) {
4325 validate_slab_slab(s, page, map);
4326 count++;
4327 }
4328 if (count != n->nr_partial)
4329 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4330 s->name, count, n->nr_partial);
4331
4332 if (!(s->flags & SLAB_STORE_USER))
4333 goto out;
4334
4335 list_for_each_entry(page, &n->full, lru) {
4336 validate_slab_slab(s, page, map);
4337 count++;
4338 }
4339 if (count != atomic_long_read(&n->nr_slabs))
4340 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4341 s->name, count, atomic_long_read(&n->nr_slabs));
4342
4343 out:
4344 spin_unlock_irqrestore(&n->list_lock, flags);
4345 return count;
4346 }
4347
4348 static long validate_slab_cache(struct kmem_cache *s)
4349 {
4350 int node;
4351 unsigned long count = 0;
4352 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4353 sizeof(unsigned long), GFP_KERNEL);
4354 struct kmem_cache_node *n;
4355
4356 if (!map)
4357 return -ENOMEM;
4358
4359 flush_all(s);
4360 for_each_kmem_cache_node(s, node, n)
4361 count += validate_slab_node(s, n, map);
4362 kfree(map);
4363 return count;
4364 }
4365 /*
4366 * Generate lists of code addresses where slabcache objects are allocated
4367 * and freed.
4368 */
4369
4370 struct location {
4371 unsigned long count;
4372 unsigned long addr;
4373 long long sum_time;
4374 long min_time;
4375 long max_time;
4376 long min_pid;
4377 long max_pid;
4378 DECLARE_BITMAP(cpus, NR_CPUS);
4379 nodemask_t nodes;
4380 };
4381
4382 struct loc_track {
4383 unsigned long max;
4384 unsigned long count;
4385 struct location *loc;
4386 };
4387
4388 static void free_loc_track(struct loc_track *t)
4389 {
4390 if (t->max)
4391 free_pages((unsigned long)t->loc,
4392 get_order(sizeof(struct location) * t->max));
4393 }
4394
4395 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4396 {
4397 struct location *l;
4398 int order;
4399
4400 order = get_order(sizeof(struct location) * max);
4401
4402 l = (void *)__get_free_pages(flags, order);
4403 if (!l)
4404 return 0;
4405
4406 if (t->count) {
4407 memcpy(l, t->loc, sizeof(struct location) * t->count);
4408 free_loc_track(t);
4409 }
4410 t->max = max;
4411 t->loc = l;
4412 return 1;
4413 }
4414
4415 static int add_location(struct loc_track *t, struct kmem_cache *s,
4416 const struct track *track)
4417 {
4418 long start, end, pos;
4419 struct location *l;
4420 unsigned long caddr;
4421 unsigned long age = jiffies - track->when;
4422
4423 start = -1;
4424 end = t->count;
4425
4426 for ( ; ; ) {
4427 pos = start + (end - start + 1) / 2;
4428
4429 /*
4430 * There is nothing at "end". If we end up there
4431 * we need to add something to before end.
4432 */
4433 if (pos == end)
4434 break;
4435
4436 caddr = t->loc[pos].addr;
4437 if (track->addr == caddr) {
4438
4439 l = &t->loc[pos];
4440 l->count++;
4441 if (track->when) {
4442 l->sum_time += age;
4443 if (age < l->min_time)
4444 l->min_time = age;
4445 if (age > l->max_time)
4446 l->max_time = age;
4447
4448 if (track->pid < l->min_pid)
4449 l->min_pid = track->pid;
4450 if (track->pid > l->max_pid)
4451 l->max_pid = track->pid;
4452
4453 cpumask_set_cpu(track->cpu,
4454 to_cpumask(l->cpus));
4455 }
4456 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4457 return 1;
4458 }
4459
4460 if (track->addr < caddr)
4461 end = pos;
4462 else
4463 start = pos;
4464 }
4465
4466 /*
4467 * Not found. Insert new tracking element.
4468 */
4469 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4470 return 0;
4471
4472 l = t->loc + pos;
4473 if (pos < t->count)
4474 memmove(l + 1, l,
4475 (t->count - pos) * sizeof(struct location));
4476 t->count++;
4477 l->count = 1;
4478 l->addr = track->addr;
4479 l->sum_time = age;
4480 l->min_time = age;
4481 l->max_time = age;
4482 l->min_pid = track->pid;
4483 l->max_pid = track->pid;
4484 cpumask_clear(to_cpumask(l->cpus));
4485 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4486 nodes_clear(l->nodes);
4487 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4488 return 1;
4489 }
4490
4491 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4492 struct page *page, enum track_item alloc,
4493 unsigned long *map)
4494 {
4495 void *addr = page_address(page);
4496 void *p;
4497
4498 bitmap_zero(map, page->objects);
4499 get_map(s, page, map);
4500
4501 for_each_object(p, s, addr, page->objects)
4502 if (!test_bit(slab_index(p, s, addr), map))
4503 add_location(t, s, get_track(s, p, alloc));
4504 }
4505
4506 static int list_locations(struct kmem_cache *s, char *buf,
4507 enum track_item alloc)
4508 {
4509 int len = 0;
4510 unsigned long i;
4511 struct loc_track t = { 0, 0, NULL };
4512 int node;
4513 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4514 sizeof(unsigned long), GFP_KERNEL);
4515 struct kmem_cache_node *n;
4516
4517 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4518 GFP_TEMPORARY)) {
4519 kfree(map);
4520 return sprintf(buf, "Out of memory\n");
4521 }
4522 /* Push back cpu slabs */
4523 flush_all(s);
4524
4525 for_each_kmem_cache_node(s, node, n) {
4526 unsigned long flags;
4527 struct page *page;
4528
4529 if (!atomic_long_read(&n->nr_slabs))
4530 continue;
4531
4532 spin_lock_irqsave(&n->list_lock, flags);
4533 list_for_each_entry(page, &n->partial, lru)
4534 process_slab(&t, s, page, alloc, map);
4535 list_for_each_entry(page, &n->full, lru)
4536 process_slab(&t, s, page, alloc, map);
4537 spin_unlock_irqrestore(&n->list_lock, flags);
4538 }
4539
4540 for (i = 0; i < t.count; i++) {
4541 struct location *l = &t.loc[i];
4542
4543 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4544 break;
4545 len += sprintf(buf + len, "%7ld ", l->count);
4546
4547 if (l->addr)
4548 len += sprintf(buf + len, "%pS", (void *)l->addr);
4549 else
4550 len += sprintf(buf + len, "<not-available>");
4551
4552 if (l->sum_time != l->min_time) {
4553 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4554 l->min_time,
4555 (long)div_u64(l->sum_time, l->count),
4556 l->max_time);
4557 } else
4558 len += sprintf(buf + len, " age=%ld",
4559 l->min_time);
4560
4561 if (l->min_pid != l->max_pid)
4562 len += sprintf(buf + len, " pid=%ld-%ld",
4563 l->min_pid, l->max_pid);
4564 else
4565 len += sprintf(buf + len, " pid=%ld",
4566 l->min_pid);
4567
4568 if (num_online_cpus() > 1 &&
4569 !cpumask_empty(to_cpumask(l->cpus)) &&
4570 len < PAGE_SIZE - 60)
4571 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4572 " cpus=%*pbl",
4573 cpumask_pr_args(to_cpumask(l->cpus)));
4574
4575 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4576 len < PAGE_SIZE - 60)
4577 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4578 " nodes=%*pbl",
4579 nodemask_pr_args(&l->nodes));
4580
4581 len += sprintf(buf + len, "\n");
4582 }
4583
4584 free_loc_track(&t);
4585 kfree(map);
4586 if (!t.count)
4587 len += sprintf(buf, "No data\n");
4588 return len;
4589 }
4590 #endif
4591
4592 #ifdef SLUB_RESILIENCY_TEST
4593 static void __init resiliency_test(void)
4594 {
4595 u8 *p;
4596
4597 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4598
4599 pr_err("SLUB resiliency testing\n");
4600 pr_err("-----------------------\n");
4601 pr_err("A. Corruption after allocation\n");
4602
4603 p = kzalloc(16, GFP_KERNEL);
4604 p[16] = 0x12;
4605 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4606 p + 16);
4607
4608 validate_slab_cache(kmalloc_caches[4]);
4609
4610 /* Hmmm... The next two are dangerous */
4611 p = kzalloc(32, GFP_KERNEL);
4612 p[32 + sizeof(void *)] = 0x34;
4613 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4614 p);
4615 pr_err("If allocated object is overwritten then not detectable\n\n");
4616
4617 validate_slab_cache(kmalloc_caches[5]);
4618 p = kzalloc(64, GFP_KERNEL);
4619 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4620 *p = 0x56;
4621 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4622 p);
4623 pr_err("If allocated object is overwritten then not detectable\n\n");
4624 validate_slab_cache(kmalloc_caches[6]);
4625
4626 pr_err("\nB. Corruption after free\n");
4627 p = kzalloc(128, GFP_KERNEL);
4628 kfree(p);
4629 *p = 0x78;
4630 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4631 validate_slab_cache(kmalloc_caches[7]);
4632
4633 p = kzalloc(256, GFP_KERNEL);
4634 kfree(p);
4635 p[50] = 0x9a;
4636 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4637 validate_slab_cache(kmalloc_caches[8]);
4638
4639 p = kzalloc(512, GFP_KERNEL);
4640 kfree(p);
4641 p[512] = 0xab;
4642 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4643 validate_slab_cache(kmalloc_caches[9]);
4644 }
4645 #else
4646 #ifdef CONFIG_SYSFS
4647 static void resiliency_test(void) {};
4648 #endif
4649 #endif
4650
4651 #ifdef CONFIG_SYSFS
4652 enum slab_stat_type {
4653 SL_ALL, /* All slabs */
4654 SL_PARTIAL, /* Only partially allocated slabs */
4655 SL_CPU, /* Only slabs used for cpu caches */
4656 SL_OBJECTS, /* Determine allocated objects not slabs */
4657 SL_TOTAL /* Determine object capacity not slabs */
4658 };
4659
4660 #define SO_ALL (1 << SL_ALL)
4661 #define SO_PARTIAL (1 << SL_PARTIAL)
4662 #define SO_CPU (1 << SL_CPU)
4663 #define SO_OBJECTS (1 << SL_OBJECTS)
4664 #define SO_TOTAL (1 << SL_TOTAL)
4665
4666 static ssize_t show_slab_objects(struct kmem_cache *s,
4667 char *buf, unsigned long flags)
4668 {
4669 unsigned long total = 0;
4670 int node;
4671 int x;
4672 unsigned long *nodes;
4673
4674 nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4675 if (!nodes)
4676 return -ENOMEM;
4677
4678 if (flags & SO_CPU) {
4679 int cpu;
4680
4681 for_each_possible_cpu(cpu) {
4682 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4683 cpu);
4684 int node;
4685 struct page *page;
4686
4687 page = READ_ONCE(c->page);
4688 if (!page)
4689 continue;
4690
4691 node = page_to_nid(page);
4692 if (flags & SO_TOTAL)
4693 x = page->objects;
4694 else if (flags & SO_OBJECTS)
4695 x = page->inuse;
4696 else
4697 x = 1;
4698
4699 total += x;
4700 nodes[node] += x;
4701
4702 page = READ_ONCE(c->partial);
4703 if (page) {
4704 node = page_to_nid(page);
4705 if (flags & SO_TOTAL)
4706 WARN_ON_ONCE(1);
4707 else if (flags & SO_OBJECTS)
4708 WARN_ON_ONCE(1);
4709 else
4710 x = page->pages;
4711 total += x;
4712 nodes[node] += x;
4713 }
4714 }
4715 }
4716
4717 get_online_mems();
4718 #ifdef CONFIG_SLUB_DEBUG
4719 if (flags & SO_ALL) {
4720 struct kmem_cache_node *n;
4721
4722 for_each_kmem_cache_node(s, node, n) {
4723
4724 if (flags & SO_TOTAL)
4725 x = atomic_long_read(&n->total_objects);
4726 else if (flags & SO_OBJECTS)
4727 x = atomic_long_read(&n->total_objects) -
4728 count_partial(n, count_free);
4729 else
4730 x = atomic_long_read(&n->nr_slabs);
4731 total += x;
4732 nodes[node] += x;
4733 }
4734
4735 } else
4736 #endif
4737 if (flags & SO_PARTIAL) {
4738 struct kmem_cache_node *n;
4739
4740 for_each_kmem_cache_node(s, node, n) {
4741 if (flags & SO_TOTAL)
4742 x = count_partial(n, count_total);
4743 else if (flags & SO_OBJECTS)
4744 x = count_partial(n, count_inuse);
4745 else
4746 x = n->nr_partial;
4747 total += x;
4748 nodes[node] += x;
4749 }
4750 }
4751 x = sprintf(buf, "%lu", total);
4752 #ifdef CONFIG_NUMA
4753 for (node = 0; node < nr_node_ids; node++)
4754 if (nodes[node])
4755 x += sprintf(buf + x, " N%d=%lu",
4756 node, nodes[node]);
4757 #endif
4758 put_online_mems();
4759 kfree(nodes);
4760 return x + sprintf(buf + x, "\n");
4761 }
4762
4763 #ifdef CONFIG_SLUB_DEBUG
4764 static int any_slab_objects(struct kmem_cache *s)
4765 {
4766 int node;
4767 struct kmem_cache_node *n;
4768
4769 for_each_kmem_cache_node(s, node, n)
4770 if (atomic_long_read(&n->total_objects))
4771 return 1;
4772
4773 return 0;
4774 }
4775 #endif
4776
4777 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4778 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4779
4780 struct slab_attribute {
4781 struct attribute attr;
4782 ssize_t (*show)(struct kmem_cache *s, char *buf);
4783 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4784 };
4785
4786 #define SLAB_ATTR_RO(_name) \
4787 static struct slab_attribute _name##_attr = \
4788 __ATTR(_name, 0400, _name##_show, NULL)
4789
4790 #define SLAB_ATTR(_name) \
4791 static struct slab_attribute _name##_attr = \
4792 __ATTR(_name, 0600, _name##_show, _name##_store)
4793
4794 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4795 {
4796 return sprintf(buf, "%d\n", s->size);
4797 }
4798 SLAB_ATTR_RO(slab_size);
4799
4800 static ssize_t align_show(struct kmem_cache *s, char *buf)
4801 {
4802 return sprintf(buf, "%d\n", s->align);
4803 }
4804 SLAB_ATTR_RO(align);
4805
4806 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4807 {
4808 return sprintf(buf, "%d\n", s->object_size);
4809 }
4810 SLAB_ATTR_RO(object_size);
4811
4812 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4813 {
4814 return sprintf(buf, "%d\n", oo_objects(s->oo));
4815 }
4816 SLAB_ATTR_RO(objs_per_slab);
4817
4818 static ssize_t order_store(struct kmem_cache *s,
4819 const char *buf, size_t length)
4820 {
4821 unsigned long order;
4822 int err;
4823
4824 err = kstrtoul(buf, 10, &order);
4825 if (err)
4826 return err;
4827
4828 if (order > slub_max_order || order < slub_min_order)
4829 return -EINVAL;
4830
4831 calculate_sizes(s, order);
4832 return length;
4833 }
4834
4835 static ssize_t order_show(struct kmem_cache *s, char *buf)
4836 {
4837 return sprintf(buf, "%d\n", oo_order(s->oo));
4838 }
4839 SLAB_ATTR(order);
4840
4841 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4842 {
4843 return sprintf(buf, "%lu\n", s->min_partial);
4844 }
4845
4846 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4847 size_t length)
4848 {
4849 unsigned long min;
4850 int err;
4851
4852 err = kstrtoul(buf, 10, &min);
4853 if (err)
4854 return err;
4855
4856 set_min_partial(s, min);
4857 return length;
4858 }
4859 SLAB_ATTR(min_partial);
4860
4861 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4862 {
4863 return sprintf(buf, "%u\n", s->cpu_partial);
4864 }
4865
4866 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4867 size_t length)
4868 {
4869 unsigned long objects;
4870 int err;
4871
4872 err = kstrtoul(buf, 10, &objects);
4873 if (err)
4874 return err;
4875 if (objects && !kmem_cache_has_cpu_partial(s))
4876 return -EINVAL;
4877
4878 s->cpu_partial = objects;
4879 flush_all(s);
4880 return length;
4881 }
4882 SLAB_ATTR(cpu_partial);
4883
4884 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4885 {
4886 if (!s->ctor)
4887 return 0;
4888 return sprintf(buf, "%pS\n", s->ctor);
4889 }
4890 SLAB_ATTR_RO(ctor);
4891
4892 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4893 {
4894 return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
4895 }
4896 SLAB_ATTR_RO(aliases);
4897
4898 static ssize_t partial_show(struct kmem_cache *s, char *buf)
4899 {
4900 return show_slab_objects(s, buf, SO_PARTIAL);
4901 }
4902 SLAB_ATTR_RO(partial);
4903
4904 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4905 {
4906 return show_slab_objects(s, buf, SO_CPU);
4907 }
4908 SLAB_ATTR_RO(cpu_slabs);
4909
4910 static ssize_t objects_show(struct kmem_cache *s, char *buf)
4911 {
4912 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4913 }
4914 SLAB_ATTR_RO(objects);
4915
4916 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4917 {
4918 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4919 }
4920 SLAB_ATTR_RO(objects_partial);
4921
4922 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4923 {
4924 int objects = 0;
4925 int pages = 0;
4926 int cpu;
4927 int len;
4928
4929 for_each_online_cpu(cpu) {
4930 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4931
4932 if (page) {
4933 pages += page->pages;
4934 objects += page->pobjects;
4935 }
4936 }
4937
4938 len = sprintf(buf, "%d(%d)", objects, pages);
4939
4940 #ifdef CONFIG_SMP
4941 for_each_online_cpu(cpu) {
4942 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4943
4944 if (page && len < PAGE_SIZE - 20)
4945 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4946 page->pobjects, page->pages);
4947 }
4948 #endif
4949 return len + sprintf(buf + len, "\n");
4950 }
4951 SLAB_ATTR_RO(slabs_cpu_partial);
4952
4953 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4954 {
4955 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4956 }
4957
4958 static ssize_t reclaim_account_store(struct kmem_cache *s,
4959 const char *buf, size_t length)
4960 {
4961 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4962 if (buf[0] == '1')
4963 s->flags |= SLAB_RECLAIM_ACCOUNT;
4964 return length;
4965 }
4966 SLAB_ATTR(reclaim_account);
4967
4968 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4969 {
4970 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4971 }
4972 SLAB_ATTR_RO(hwcache_align);
4973
4974 #ifdef CONFIG_ZONE_DMA
4975 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4976 {
4977 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4978 }
4979 SLAB_ATTR_RO(cache_dma);
4980 #endif
4981
4982 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4983 {
4984 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4985 }
4986 SLAB_ATTR_RO(destroy_by_rcu);
4987
4988 static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4989 {
4990 return sprintf(buf, "%d\n", s->reserved);
4991 }
4992 SLAB_ATTR_RO(reserved);
4993
4994 #ifdef CONFIG_SLUB_DEBUG
4995 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4996 {
4997 return show_slab_objects(s, buf, SO_ALL);
4998 }
4999 SLAB_ATTR_RO(slabs);
5000
5001 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5002 {
5003 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5004 }
5005 SLAB_ATTR_RO(total_objects);
5006
5007 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5008 {
5009 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5010 }
5011
5012 static ssize_t sanity_checks_store(struct kmem_cache *s,
5013 const char *buf, size_t length)
5014 {
5015 s->flags &= ~SLAB_CONSISTENCY_CHECKS;
5016 if (buf[0] == '1') {
5017 s->flags &= ~__CMPXCHG_DOUBLE;
5018 s->flags |= SLAB_CONSISTENCY_CHECKS;
5019 }
5020 return length;
5021 }
5022 SLAB_ATTR(sanity_checks);
5023
5024 static ssize_t trace_show(struct kmem_cache *s, char *buf)
5025 {
5026 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5027 }
5028
5029 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
5030 size_t length)
5031 {
5032 /*
5033 * Tracing a merged cache is going to give confusing results
5034 * as well as cause other issues like converting a mergeable
5035 * cache into an umergeable one.
5036 */
5037 if (s->refcount > 1)
5038 return -EINVAL;
5039
5040 s->flags &= ~SLAB_TRACE;
5041 if (buf[0] == '1') {
5042 s->flags &= ~__CMPXCHG_DOUBLE;
5043 s->flags |= SLAB_TRACE;
5044 }
5045 return length;
5046 }
5047 SLAB_ATTR(trace);
5048
5049 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5050 {
5051 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5052 }
5053
5054 static ssize_t red_zone_store(struct kmem_cache *s,
5055 const char *buf, size_t length)
5056 {
5057 if (any_slab_objects(s))
5058 return -EBUSY;
5059
5060 s->flags &= ~SLAB_RED_ZONE;
5061 if (buf[0] == '1') {
5062 s->flags |= SLAB_RED_ZONE;
5063 }
5064 calculate_sizes(s, -1);
5065 return length;
5066 }
5067 SLAB_ATTR(red_zone);
5068
5069 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5070 {
5071 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5072 }
5073
5074 static ssize_t poison_store(struct kmem_cache *s,
5075 const char *buf, size_t length)
5076 {
5077 if (any_slab_objects(s))
5078 return -EBUSY;
5079
5080 s->flags &= ~SLAB_POISON;
5081 if (buf[0] == '1') {
5082 s->flags |= SLAB_POISON;
5083 }
5084 calculate_sizes(s, -1);
5085 return length;
5086 }
5087 SLAB_ATTR(poison);
5088
5089 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5090 {
5091 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5092 }
5093
5094 static ssize_t store_user_store(struct kmem_cache *s,
5095 const char *buf, size_t length)
5096 {
5097 if (any_slab_objects(s))
5098 return -EBUSY;
5099
5100 s->flags &= ~SLAB_STORE_USER;
5101 if (buf[0] == '1') {
5102 s->flags &= ~__CMPXCHG_DOUBLE;
5103 s->flags |= SLAB_STORE_USER;
5104 }
5105 calculate_sizes(s, -1);
5106 return length;
5107 }
5108 SLAB_ATTR(store_user);
5109
5110 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5111 {
5112 return 0;
5113 }
5114
5115 static ssize_t validate_store(struct kmem_cache *s,
5116 const char *buf, size_t length)
5117 {
5118 int ret = -EINVAL;
5119
5120 if (buf[0] == '1') {
5121 ret = validate_slab_cache(s);
5122 if (ret >= 0)
5123 ret = length;
5124 }
5125 return ret;
5126 }
5127 SLAB_ATTR(validate);
5128
5129 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5130 {
5131 if (!(s->flags & SLAB_STORE_USER))
5132 return -ENOSYS;
5133 return list_locations(s, buf, TRACK_ALLOC);
5134 }
5135 SLAB_ATTR_RO(alloc_calls);
5136
5137 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5138 {
5139 if (!(s->flags & SLAB_STORE_USER))
5140 return -ENOSYS;
5141 return list_locations(s, buf, TRACK_FREE);
5142 }
5143 SLAB_ATTR_RO(free_calls);
5144 #endif /* CONFIG_SLUB_DEBUG */
5145
5146 #ifdef CONFIG_FAILSLAB
5147 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5148 {
5149 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5150 }
5151
5152 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5153 size_t length)
5154 {
5155 if (s->refcount > 1)
5156 return -EINVAL;
5157
5158 s->flags &= ~SLAB_FAILSLAB;
5159 if (buf[0] == '1')
5160 s->flags |= SLAB_FAILSLAB;
5161 return length;
5162 }
5163 SLAB_ATTR(failslab);
5164 #endif
5165
5166 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5167 {
5168 return 0;
5169 }
5170
5171 static ssize_t shrink_store(struct kmem_cache *s,
5172 const char *buf, size_t length)
5173 {
5174 if (buf[0] == '1')
5175 kmem_cache_shrink(s);
5176 else
5177 return -EINVAL;
5178 return length;
5179 }
5180 SLAB_ATTR(shrink);
5181
5182 #ifdef CONFIG_NUMA
5183 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5184 {
5185 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
5186 }
5187
5188 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5189 const char *buf, size_t length)
5190 {
5191 unsigned long ratio;
5192 int err;
5193
5194 err = kstrtoul(buf, 10, &ratio);
5195 if (err)
5196 return err;
5197
5198 if (ratio <= 100)
5199 s->remote_node_defrag_ratio = ratio * 10;
5200
5201 return length;
5202 }
5203 SLAB_ATTR(remote_node_defrag_ratio);
5204 #endif
5205
5206 #ifdef CONFIG_SLUB_STATS
5207 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5208 {
5209 unsigned long sum = 0;
5210 int cpu;
5211 int len;
5212 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5213
5214 if (!data)
5215 return -ENOMEM;
5216
5217 for_each_online_cpu(cpu) {
5218 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5219
5220 data[cpu] = x;
5221 sum += x;
5222 }
5223
5224 len = sprintf(buf, "%lu", sum);
5225
5226 #ifdef CONFIG_SMP
5227 for_each_online_cpu(cpu) {
5228 if (data[cpu] && len < PAGE_SIZE - 20)
5229 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5230 }
5231 #endif
5232 kfree(data);
5233 return len + sprintf(buf + len, "\n");
5234 }
5235
5236 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5237 {
5238 int cpu;
5239
5240 for_each_online_cpu(cpu)
5241 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5242 }
5243
5244 #define STAT_ATTR(si, text) \
5245 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5246 { \
5247 return show_stat(s, buf, si); \
5248 } \
5249 static ssize_t text##_store(struct kmem_cache *s, \
5250 const char *buf, size_t length) \
5251 { \
5252 if (buf[0] != '0') \
5253 return -EINVAL; \
5254 clear_stat(s, si); \
5255 return length; \
5256 } \
5257 SLAB_ATTR(text); \
5258
5259 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5260 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5261 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5262 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5263 STAT_ATTR(FREE_FROZEN, free_frozen);
5264 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5265 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5266 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5267 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5268 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5269 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5270 STAT_ATTR(FREE_SLAB, free_slab);
5271 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5272 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5273 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5274 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5275 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5276 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5277 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5278 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5279 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5280 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5281 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5282 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5283 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5284 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5285 #endif
5286
5287 static struct attribute *slab_attrs[] = {
5288 &slab_size_attr.attr,
5289 &object_size_attr.attr,
5290 &objs_per_slab_attr.attr,
5291 &order_attr.attr,
5292 &min_partial_attr.attr,
5293 &cpu_partial_attr.attr,
5294 &objects_attr.attr,
5295 &objects_partial_attr.attr,
5296 &partial_attr.attr,
5297 &cpu_slabs_attr.attr,
5298 &ctor_attr.attr,
5299 &aliases_attr.attr,
5300 &align_attr.attr,
5301 &hwcache_align_attr.attr,
5302 &reclaim_account_attr.attr,
5303 &destroy_by_rcu_attr.attr,
5304 &shrink_attr.attr,
5305 &reserved_attr.attr,
5306 &slabs_cpu_partial_attr.attr,
5307 #ifdef CONFIG_SLUB_DEBUG
5308 &total_objects_attr.attr,
5309 &slabs_attr.attr,
5310 &sanity_checks_attr.attr,
5311 &trace_attr.attr,
5312 &red_zone_attr.attr,
5313 &poison_attr.attr,
5314 &store_user_attr.attr,
5315 &validate_attr.attr,
5316 &alloc_calls_attr.attr,
5317 &free_calls_attr.attr,
5318 #endif
5319 #ifdef CONFIG_ZONE_DMA
5320 &cache_dma_attr.attr,
5321 #endif
5322 #ifdef CONFIG_NUMA
5323 &remote_node_defrag_ratio_attr.attr,
5324 #endif
5325 #ifdef CONFIG_SLUB_STATS
5326 &alloc_fastpath_attr.attr,
5327 &alloc_slowpath_attr.attr,
5328 &free_fastpath_attr.attr,
5329 &free_slowpath_attr.attr,
5330 &free_frozen_attr.attr,
5331 &free_add_partial_attr.attr,
5332 &free_remove_partial_attr.attr,
5333 &alloc_from_partial_attr.attr,
5334 &alloc_slab_attr.attr,
5335 &alloc_refill_attr.attr,
5336 &alloc_node_mismatch_attr.attr,
5337 &free_slab_attr.attr,
5338 &cpuslab_flush_attr.attr,
5339 &deactivate_full_attr.attr,
5340 &deactivate_empty_attr.attr,
5341 &deactivate_to_head_attr.attr,
5342 &deactivate_to_tail_attr.attr,
5343 &deactivate_remote_frees_attr.attr,
5344 &deactivate_bypass_attr.attr,
5345 &order_fallback_attr.attr,
5346 &cmpxchg_double_fail_attr.attr,
5347 &cmpxchg_double_cpu_fail_attr.attr,
5348 &cpu_partial_alloc_attr.attr,
5349 &cpu_partial_free_attr.attr,
5350 &cpu_partial_node_attr.attr,
5351 &cpu_partial_drain_attr.attr,
5352 #endif
5353 #ifdef CONFIG_FAILSLAB
5354 &failslab_attr.attr,
5355 #endif
5356
5357 NULL
5358 };
5359
5360 static struct attribute_group slab_attr_group = {
5361 .attrs = slab_attrs,
5362 };
5363
5364 static ssize_t slab_attr_show(struct kobject *kobj,
5365 struct attribute *attr,
5366 char *buf)
5367 {
5368 struct slab_attribute *attribute;
5369 struct kmem_cache *s;
5370 int err;
5371
5372 attribute = to_slab_attr(attr);
5373 s = to_slab(kobj);
5374
5375 if (!attribute->show)
5376 return -EIO;
5377
5378 err = attribute->show(s, buf);
5379
5380 return err;
5381 }
5382
5383 static ssize_t slab_attr_store(struct kobject *kobj,
5384 struct attribute *attr,
5385 const char *buf, size_t len)
5386 {
5387 struct slab_attribute *attribute;
5388 struct kmem_cache *s;
5389 int err;
5390
5391 attribute = to_slab_attr(attr);
5392 s = to_slab(kobj);
5393
5394 if (!attribute->store)
5395 return -EIO;
5396
5397 err = attribute->store(s, buf, len);
5398 #ifdef CONFIG_MEMCG
5399 if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5400 struct kmem_cache *c;
5401
5402 mutex_lock(&slab_mutex);
5403 if (s->max_attr_size < len)
5404 s->max_attr_size = len;
5405
5406 /*
5407 * This is a best effort propagation, so this function's return
5408 * value will be determined by the parent cache only. This is
5409 * basically because not all attributes will have a well
5410 * defined semantics for rollbacks - most of the actions will
5411 * have permanent effects.
5412 *
5413 * Returning the error value of any of the children that fail
5414 * is not 100 % defined, in the sense that users seeing the
5415 * error code won't be able to know anything about the state of
5416 * the cache.
5417 *
5418 * Only returning the error code for the parent cache at least
5419 * has well defined semantics. The cache being written to
5420 * directly either failed or succeeded, in which case we loop
5421 * through the descendants with best-effort propagation.
5422 */
5423 for_each_memcg_cache(c, s)
5424 attribute->store(c, buf, len);
5425 mutex_unlock(&slab_mutex);
5426 }
5427 #endif
5428 return err;
5429 }
5430
5431 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5432 {
5433 #ifdef CONFIG_MEMCG
5434 int i;
5435 char *buffer = NULL;
5436 struct kmem_cache *root_cache;
5437
5438 if (is_root_cache(s))
5439 return;
5440
5441 root_cache = s->memcg_params.root_cache;
5442
5443 /*
5444 * This mean this cache had no attribute written. Therefore, no point
5445 * in copying default values around
5446 */
5447 if (!root_cache->max_attr_size)
5448 return;
5449
5450 for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5451 char mbuf[64];
5452 char *buf;
5453 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5454
5455 if (!attr || !attr->store || !attr->show)
5456 continue;
5457
5458 /*
5459 * It is really bad that we have to allocate here, so we will
5460 * do it only as a fallback. If we actually allocate, though,
5461 * we can just use the allocated buffer until the end.
5462 *
5463 * Most of the slub attributes will tend to be very small in
5464 * size, but sysfs allows buffers up to a page, so they can
5465 * theoretically happen.
5466 */
5467 if (buffer)
5468 buf = buffer;
5469 else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5470 buf = mbuf;
5471 else {
5472 buffer = (char *) get_zeroed_page(GFP_KERNEL);
5473 if (WARN_ON(!buffer))
5474 continue;
5475 buf = buffer;
5476 }
5477
5478 attr->show(root_cache, buf);
5479 attr->store(s, buf, strlen(buf));
5480 }
5481
5482 if (buffer)
5483 free_page((unsigned long)buffer);
5484 #endif
5485 }
5486
5487 static void kmem_cache_release(struct kobject *k)
5488 {
5489 slab_kmem_cache_release(to_slab(k));
5490 }
5491
5492 static const struct sysfs_ops slab_sysfs_ops = {
5493 .show = slab_attr_show,
5494 .store = slab_attr_store,
5495 };
5496
5497 static struct kobj_type slab_ktype = {
5498 .sysfs_ops = &slab_sysfs_ops,
5499 .release = kmem_cache_release,
5500 };
5501
5502 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5503 {
5504 struct kobj_type *ktype = get_ktype(kobj);
5505
5506 if (ktype == &slab_ktype)
5507 return 1;
5508 return 0;
5509 }
5510
5511 static const struct kset_uevent_ops slab_uevent_ops = {
5512 .filter = uevent_filter,
5513 };
5514
5515 static struct kset *slab_kset;
5516
5517 static inline struct kset *cache_kset(struct kmem_cache *s)
5518 {
5519 #ifdef CONFIG_MEMCG
5520 if (!is_root_cache(s))
5521 return s->memcg_params.root_cache->memcg_kset;
5522 #endif
5523 return slab_kset;
5524 }
5525
5526 #define ID_STR_LENGTH 64
5527
5528 /* Create a unique string id for a slab cache:
5529 *
5530 * Format :[flags-]size
5531 */
5532 static char *create_unique_id(struct kmem_cache *s)
5533 {
5534 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5535 char *p = name;
5536
5537 BUG_ON(!name);
5538
5539 *p++ = ':';
5540 /*
5541 * First flags affecting slabcache operations. We will only
5542 * get here for aliasable slabs so we do not need to support
5543 * too many flags. The flags here must cover all flags that
5544 * are matched during merging to guarantee that the id is
5545 * unique.
5546 */
5547 if (s->flags & SLAB_CACHE_DMA)
5548 *p++ = 'd';
5549 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5550 *p++ = 'a';
5551 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5552 *p++ = 'F';
5553 if (!(s->flags & SLAB_NOTRACK))
5554 *p++ = 't';
5555 if (s->flags & SLAB_ACCOUNT)
5556 *p++ = 'A';
5557 if (p != name + 1)
5558 *p++ = '-';
5559 p += sprintf(p, "%07d", s->size);
5560
5561 BUG_ON(p > name + ID_STR_LENGTH - 1);
5562 return name;
5563 }
5564
5565 static int sysfs_slab_add(struct kmem_cache *s)
5566 {
5567 int err;
5568 const char *name;
5569 int unmergeable = slab_unmergeable(s);
5570
5571 if (unmergeable) {
5572 /*
5573 * Slabcache can never be merged so we can use the name proper.
5574 * This is typically the case for debug situations. In that
5575 * case we can catch duplicate names easily.
5576 */
5577 sysfs_remove_link(&slab_kset->kobj, s->name);
5578 name = s->name;
5579 } else {
5580 /*
5581 * Create a unique name for the slab as a target
5582 * for the symlinks.
5583 */
5584 name = create_unique_id(s);
5585 }
5586
5587 s->kobj.kset = cache_kset(s);
5588 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5589 if (err)
5590 goto out;
5591
5592 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5593 if (err)
5594 goto out_del_kobj;
5595
5596 #ifdef CONFIG_MEMCG
5597 if (is_root_cache(s)) {
5598 s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5599 if (!s->memcg_kset) {
5600 err = -ENOMEM;
5601 goto out_del_kobj;
5602 }
5603 }
5604 #endif
5605
5606 kobject_uevent(&s->kobj, KOBJ_ADD);
5607 if (!unmergeable) {
5608 /* Setup first alias */
5609 sysfs_slab_alias(s, s->name);
5610 }
5611 out:
5612 if (!unmergeable)
5613 kfree(name);
5614 return err;
5615 out_del_kobj:
5616 kobject_del(&s->kobj);
5617 goto out;
5618 }
5619
5620 void sysfs_slab_remove(struct kmem_cache *s)
5621 {
5622 if (slab_state < FULL)
5623 /*
5624 * Sysfs has not been setup yet so no need to remove the
5625 * cache from sysfs.
5626 */
5627 return;
5628
5629 #ifdef CONFIG_MEMCG
5630 kset_unregister(s->memcg_kset);
5631 #endif
5632 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5633 kobject_del(&s->kobj);
5634 kobject_put(&s->kobj);
5635 }
5636
5637 /*
5638 * Need to buffer aliases during bootup until sysfs becomes
5639 * available lest we lose that information.
5640 */
5641 struct saved_alias {
5642 struct kmem_cache *s;
5643 const char *name;
5644 struct saved_alias *next;
5645 };
5646
5647 static struct saved_alias *alias_list;
5648
5649 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5650 {
5651 struct saved_alias *al;
5652
5653 if (slab_state == FULL) {
5654 /*
5655 * If we have a leftover link then remove it.
5656 */
5657 sysfs_remove_link(&slab_kset->kobj, name);
5658 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5659 }
5660
5661 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5662 if (!al)
5663 return -ENOMEM;
5664
5665 al->s = s;
5666 al->name = name;
5667 al->next = alias_list;
5668 alias_list = al;
5669 return 0;
5670 }
5671
5672 static int __init slab_sysfs_init(void)
5673 {
5674 struct kmem_cache *s;
5675 int err;
5676
5677 mutex_lock(&slab_mutex);
5678
5679 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5680 if (!slab_kset) {
5681 mutex_unlock(&slab_mutex);
5682 pr_err("Cannot register slab subsystem.\n");
5683 return -ENOSYS;
5684 }
5685
5686 slab_state = FULL;
5687
5688 list_for_each_entry(s, &slab_caches, list) {
5689 err = sysfs_slab_add(s);
5690 if (err)
5691 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5692 s->name);
5693 }
5694
5695 while (alias_list) {
5696 struct saved_alias *al = alias_list;
5697
5698 alias_list = alias_list->next;
5699 err = sysfs_slab_alias(al->s, al->name);
5700 if (err)
5701 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5702 al->name);
5703 kfree(al);
5704 }
5705
5706 mutex_unlock(&slab_mutex);
5707 resiliency_test();
5708 return 0;
5709 }
5710
5711 __initcall(slab_sysfs_init);
5712 #endif /* CONFIG_SYSFS */
5713
5714 /*
5715 * The /proc/slabinfo ABI
5716 */
5717 #ifdef CONFIG_SLABINFO
5718 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5719 {
5720 unsigned long nr_slabs = 0;
5721 unsigned long nr_objs = 0;
5722 unsigned long nr_free = 0;
5723 int node;
5724 struct kmem_cache_node *n;
5725
5726 for_each_kmem_cache_node(s, node, n) {
5727 nr_slabs += node_nr_slabs(n);
5728 nr_objs += node_nr_objs(n);
5729 nr_free += count_partial(n, count_free);
5730 }
5731
5732 sinfo->active_objs = nr_objs - nr_free;
5733 sinfo->num_objs = nr_objs;
5734 sinfo->active_slabs = nr_slabs;
5735 sinfo->num_slabs = nr_slabs;
5736 sinfo->objects_per_slab = oo_objects(s->oo);
5737 sinfo->cache_order = oo_order(s->oo);
5738 }
5739
5740 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5741 {
5742 }
5743
5744 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5745 size_t count, loff_t *ppos)
5746 {
5747 return -EIO;
5748 }
5749 #endif /* CONFIG_SLABINFO */