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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SLUB: A slab allocator that limits cache line use instead of queuing
4 * objects in per cpu and per node lists.
5 *
6 * The allocator synchronizes using per slab locks or atomic operations
7 * and only uses a centralized lock to manage a pool of partial slabs.
8 *
9 * (C) 2007 SGI, Christoph Lameter
10 * (C) 2011 Linux Foundation, Christoph Lameter
11 */
12
13#include <linux/mm.h>
14#include <linux/swap.h> /* struct reclaim_state */
15#include <linux/module.h>
16#include <linux/bit_spinlock.h>
17#include <linux/interrupt.h>
18#include <linux/swab.h>
19#include <linux/bitops.h>
20#include <linux/slab.h>
21#include "slab.h"
22#include <linux/proc_fs.h>
23#include <linux/seq_file.h>
24#include <linux/kasan.h>
25#include <linux/kmsan.h>
26#include <linux/cpu.h>
27#include <linux/cpuset.h>
28#include <linux/mempolicy.h>
29#include <linux/ctype.h>
30#include <linux/stackdepot.h>
31#include <linux/debugobjects.h>
32#include <linux/kallsyms.h>
33#include <linux/kfence.h>
34#include <linux/memory.h>
35#include <linux/math64.h>
36#include <linux/fault-inject.h>
37#include <linux/stacktrace.h>
38#include <linux/prefetch.h>
39#include <linux/memcontrol.h>
40#include <linux/random.h>
41#include <kunit/test.h>
42#include <kunit/test-bug.h>
43#include <linux/sort.h>
44
45#include <linux/debugfs.h>
46#include <trace/events/kmem.h>
47
48#include "internal.h"
49
50/*
51 * Lock order:
52 * 1. slab_mutex (Global Mutex)
53 * 2. node->list_lock (Spinlock)
54 * 3. kmem_cache->cpu_slab->lock (Local lock)
55 * 4. slab_lock(slab) (Only on some arches)
56 * 5. object_map_lock (Only for debugging)
57 *
58 * slab_mutex
59 *
60 * The role of the slab_mutex is to protect the list of all the slabs
61 * and to synchronize major metadata changes to slab cache structures.
62 * Also synchronizes memory hotplug callbacks.
63 *
64 * slab_lock
65 *
66 * The slab_lock is a wrapper around the page lock, thus it is a bit
67 * spinlock.
68 *
69 * The slab_lock is only used on arches that do not have the ability
70 * to do a cmpxchg_double. It only protects:
71 *
72 * A. slab->freelist -> List of free objects in a slab
73 * B. slab->inuse -> Number of objects in use
74 * C. slab->objects -> Number of objects in slab
75 * D. slab->frozen -> frozen state
76 *
77 * Frozen slabs
78 *
79 * If a slab is frozen then it is exempt from list management. It is not
80 * on any list except per cpu partial list. The processor that froze the
81 * slab is the one who can perform list operations on the slab. Other
82 * processors may put objects onto the freelist but the processor that
83 * froze the slab is the only one that can retrieve the objects from the
84 * slab's freelist.
85 *
86 * list_lock
87 *
88 * The list_lock protects the partial and full list on each node and
89 * the partial slab counter. If taken then no new slabs may be added or
90 * removed from the lists nor make the number of partial slabs be modified.
91 * (Note that the total number of slabs is an atomic value that may be
92 * modified without taking the list lock).
93 *
94 * The list_lock is a centralized lock and thus we avoid taking it as
95 * much as possible. As long as SLUB does not have to handle partial
96 * slabs, operations can continue without any centralized lock. F.e.
97 * allocating a long series of objects that fill up slabs does not require
98 * the list lock.
99 *
100 * For debug caches, all allocations are forced to go through a list_lock
101 * protected region to serialize against concurrent validation.
102 *
103 * cpu_slab->lock local lock
104 *
105 * This locks protect slowpath manipulation of all kmem_cache_cpu fields
106 * except the stat counters. This is a percpu structure manipulated only by
107 * the local cpu, so the lock protects against being preempted or interrupted
108 * by an irq. Fast path operations rely on lockless operations instead.
109 *
110 * On PREEMPT_RT, the local lock neither disables interrupts nor preemption
111 * which means the lockless fastpath cannot be used as it might interfere with
112 * an in-progress slow path operations. In this case the local lock is always
113 * taken but it still utilizes the freelist for the common operations.
114 *
115 * lockless fastpaths
116 *
117 * The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
118 * are fully lockless when satisfied from the percpu slab (and when
119 * cmpxchg_double is possible to use, otherwise slab_lock is taken).
120 * They also don't disable preemption or migration or irqs. They rely on
121 * the transaction id (tid) field to detect being preempted or moved to
122 * another cpu.
123 *
124 * irq, preemption, migration considerations
125 *
126 * Interrupts are disabled as part of list_lock or local_lock operations, or
127 * around the slab_lock operation, in order to make the slab allocator safe
128 * to use in the context of an irq.
129 *
130 * In addition, preemption (or migration on PREEMPT_RT) is disabled in the
131 * allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
132 * local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
133 * doesn't have to be revalidated in each section protected by the local lock.
134 *
135 * SLUB assigns one slab for allocation to each processor.
136 * Allocations only occur from these slabs called cpu slabs.
137 *
138 * Slabs with free elements are kept on a partial list and during regular
139 * operations no list for full slabs is used. If an object in a full slab is
140 * freed then the slab will show up again on the partial lists.
141 * We track full slabs for debugging purposes though because otherwise we
142 * cannot scan all objects.
143 *
144 * Slabs are freed when they become empty. Teardown and setup is
145 * minimal so we rely on the page allocators per cpu caches for
146 * fast frees and allocs.
147 *
148 * slab->frozen The slab is frozen and exempt from list processing.
149 * This means that the slab is dedicated to a purpose
150 * such as satisfying allocations for a specific
151 * processor. Objects may be freed in the slab while
152 * it is frozen but slab_free will then skip the usual
153 * list operations. It is up to the processor holding
154 * the slab to integrate the slab into the slab lists
155 * when the slab is no longer needed.
156 *
157 * One use of this flag is to mark slabs that are
158 * used for allocations. Then such a slab becomes a cpu
159 * slab. The cpu slab may be equipped with an additional
160 * freelist that allows lockless access to
161 * free objects in addition to the regular freelist
162 * that requires the slab lock.
163 *
164 * SLAB_DEBUG_FLAGS Slab requires special handling due to debug
165 * options set. This moves slab handling out of
166 * the fast path and disables lockless freelists.
167 */
168
169/*
170 * We could simply use migrate_disable()/enable() but as long as it's a
171 * function call even on !PREEMPT_RT, use inline preempt_disable() there.
172 */
173#ifndef CONFIG_PREEMPT_RT
174#define slub_get_cpu_ptr(var) get_cpu_ptr(var)
175#define slub_put_cpu_ptr(var) put_cpu_ptr(var)
176#define USE_LOCKLESS_FAST_PATH() (true)
177#else
178#define slub_get_cpu_ptr(var) \
179({ \
180 migrate_disable(); \
181 this_cpu_ptr(var); \
182})
183#define slub_put_cpu_ptr(var) \
184do { \
185 (void)(var); \
186 migrate_enable(); \
187} while (0)
188#define USE_LOCKLESS_FAST_PATH() (false)
189#endif
190
191#ifndef CONFIG_SLUB_TINY
192#define __fastpath_inline __always_inline
193#else
194#define __fastpath_inline
195#endif
196
197#ifdef CONFIG_SLUB_DEBUG
198#ifdef CONFIG_SLUB_DEBUG_ON
199DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
200#else
201DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
202#endif
203#endif /* CONFIG_SLUB_DEBUG */
204
205/* Structure holding parameters for get_partial() call chain */
206struct partial_context {
207 struct slab **slab;
208 gfp_t flags;
209 unsigned int orig_size;
210};
211
212static inline bool kmem_cache_debug(struct kmem_cache *s)
213{
214 return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
215}
216
217static inline bool slub_debug_orig_size(struct kmem_cache *s)
218{
219 return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
220 (s->flags & SLAB_KMALLOC));
221}
222
223void *fixup_red_left(struct kmem_cache *s, void *p)
224{
225 if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
226 p += s->red_left_pad;
227
228 return p;
229}
230
231static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
232{
233#ifdef CONFIG_SLUB_CPU_PARTIAL
234 return !kmem_cache_debug(s);
235#else
236 return false;
237#endif
238}
239
240/*
241 * Issues still to be resolved:
242 *
243 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
244 *
245 * - Variable sizing of the per node arrays
246 */
247
248/* Enable to log cmpxchg failures */
249#undef SLUB_DEBUG_CMPXCHG
250
251#ifndef CONFIG_SLUB_TINY
252/*
253 * Minimum number of partial slabs. These will be left on the partial
254 * lists even if they are empty. kmem_cache_shrink may reclaim them.
255 */
256#define MIN_PARTIAL 5
257
258/*
259 * Maximum number of desirable partial slabs.
260 * The existence of more partial slabs makes kmem_cache_shrink
261 * sort the partial list by the number of objects in use.
262 */
263#define MAX_PARTIAL 10
264#else
265#define MIN_PARTIAL 0
266#define MAX_PARTIAL 0
267#endif
268
269#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
270 SLAB_POISON | SLAB_STORE_USER)
271
272/*
273 * These debug flags cannot use CMPXCHG because there might be consistency
274 * issues when checking or reading debug information
275 */
276#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
277 SLAB_TRACE)
278
279
280/*
281 * Debugging flags that require metadata to be stored in the slab. These get
282 * disabled when slub_debug=O is used and a cache's min order increases with
283 * metadata.
284 */
285#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
286
287#define OO_SHIFT 16
288#define OO_MASK ((1 << OO_SHIFT) - 1)
289#define MAX_OBJS_PER_PAGE 32767 /* since slab.objects is u15 */
290
291/* Internal SLUB flags */
292/* Poison object */
293#define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
294/* Use cmpxchg_double */
295#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
296
297/*
298 * Tracking user of a slab.
299 */
300#define TRACK_ADDRS_COUNT 16
301struct track {
302 unsigned long addr; /* Called from address */
303#ifdef CONFIG_STACKDEPOT
304 depot_stack_handle_t handle;
305#endif
306 int cpu; /* Was running on cpu */
307 int pid; /* Pid context */
308 unsigned long when; /* When did the operation occur */
309};
310
311enum track_item { TRACK_ALLOC, TRACK_FREE };
312
313#ifdef SLAB_SUPPORTS_SYSFS
314static int sysfs_slab_add(struct kmem_cache *);
315static int sysfs_slab_alias(struct kmem_cache *, const char *);
316#else
317static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
318static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
319 { return 0; }
320#endif
321
322#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
323static void debugfs_slab_add(struct kmem_cache *);
324#else
325static inline void debugfs_slab_add(struct kmem_cache *s) { }
326#endif
327
328static inline void stat(const struct kmem_cache *s, enum stat_item si)
329{
330#ifdef CONFIG_SLUB_STATS
331 /*
332 * The rmw is racy on a preemptible kernel but this is acceptable, so
333 * avoid this_cpu_add()'s irq-disable overhead.
334 */
335 raw_cpu_inc(s->cpu_slab->stat[si]);
336#endif
337}
338
339/*
340 * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
341 * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
342 * differ during memory hotplug/hotremove operations.
343 * Protected by slab_mutex.
344 */
345static nodemask_t slab_nodes;
346
347#ifndef CONFIG_SLUB_TINY
348/*
349 * Workqueue used for flush_cpu_slab().
350 */
351static struct workqueue_struct *flushwq;
352#endif
353
354/********************************************************************
355 * Core slab cache functions
356 *******************************************************************/
357
358/*
359 * Returns freelist pointer (ptr). With hardening, this is obfuscated
360 * with an XOR of the address where the pointer is held and a per-cache
361 * random number.
362 */
363static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
364 unsigned long ptr_addr)
365{
366#ifdef CONFIG_SLAB_FREELIST_HARDENED
367 /*
368 * When CONFIG_KASAN_SW/HW_TAGS is enabled, ptr_addr might be tagged.
369 * Normally, this doesn't cause any issues, as both set_freepointer()
370 * and get_freepointer() are called with a pointer with the same tag.
371 * However, there are some issues with CONFIG_SLUB_DEBUG code. For
372 * example, when __free_slub() iterates over objects in a cache, it
373 * passes untagged pointers to check_object(). check_object() in turns
374 * calls get_freepointer() with an untagged pointer, which causes the
375 * freepointer to be restored incorrectly.
376 */
377 return (void *)((unsigned long)ptr ^ s->random ^
378 swab((unsigned long)kasan_reset_tag((void *)ptr_addr)));
379#else
380 return ptr;
381#endif
382}
383
384/* Returns the freelist pointer recorded at location ptr_addr. */
385static inline void *freelist_dereference(const struct kmem_cache *s,
386 void *ptr_addr)
387{
388 return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
389 (unsigned long)ptr_addr);
390}
391
392static inline void *get_freepointer(struct kmem_cache *s, void *object)
393{
394 object = kasan_reset_tag(object);
395 return freelist_dereference(s, object + s->offset);
396}
397
398#ifndef CONFIG_SLUB_TINY
399static void prefetch_freepointer(const struct kmem_cache *s, void *object)
400{
401 prefetchw(object + s->offset);
402}
403#endif
404
405/*
406 * When running under KMSAN, get_freepointer_safe() may return an uninitialized
407 * pointer value in the case the current thread loses the race for the next
408 * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
409 * slab_alloc_node() will fail, so the uninitialized value won't be used, but
410 * KMSAN will still check all arguments of cmpxchg because of imperfect
411 * handling of inline assembly.
412 * To work around this problem, we apply __no_kmsan_checks to ensure that
413 * get_freepointer_safe() returns initialized memory.
414 */
415__no_kmsan_checks
416static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
417{
418 unsigned long freepointer_addr;
419 void *p;
420
421 if (!debug_pagealloc_enabled_static())
422 return get_freepointer(s, object);
423
424 object = kasan_reset_tag(object);
425 freepointer_addr = (unsigned long)object + s->offset;
426 copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
427 return freelist_ptr(s, p, freepointer_addr);
428}
429
430static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
431{
432 unsigned long freeptr_addr = (unsigned long)object + s->offset;
433
434#ifdef CONFIG_SLAB_FREELIST_HARDENED
435 BUG_ON(object == fp); /* naive detection of double free or corruption */
436#endif
437
438 freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
439 *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
440}
441
442/* Loop over all objects in a slab */
443#define for_each_object(__p, __s, __addr, __objects) \
444 for (__p = fixup_red_left(__s, __addr); \
445 __p < (__addr) + (__objects) * (__s)->size; \
446 __p += (__s)->size)
447
448static inline unsigned int order_objects(unsigned int order, unsigned int size)
449{
450 return ((unsigned int)PAGE_SIZE << order) / size;
451}
452
453static inline struct kmem_cache_order_objects oo_make(unsigned int order,
454 unsigned int size)
455{
456 struct kmem_cache_order_objects x = {
457 (order << OO_SHIFT) + order_objects(order, size)
458 };
459
460 return x;
461}
462
463static inline unsigned int oo_order(struct kmem_cache_order_objects x)
464{
465 return x.x >> OO_SHIFT;
466}
467
468static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
469{
470 return x.x & OO_MASK;
471}
472
473#ifdef CONFIG_SLUB_CPU_PARTIAL
474static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
475{
476 unsigned int nr_slabs;
477
478 s->cpu_partial = nr_objects;
479
480 /*
481 * We take the number of objects but actually limit the number of
482 * slabs on the per cpu partial list, in order to limit excessive
483 * growth of the list. For simplicity we assume that the slabs will
484 * be half-full.
485 */
486 nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
487 s->cpu_partial_slabs = nr_slabs;
488}
489#else
490static inline void
491slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
492{
493}
494#endif /* CONFIG_SLUB_CPU_PARTIAL */
495
496/*
497 * Per slab locking using the pagelock
498 */
499static __always_inline void slab_lock(struct slab *slab)
500{
501 struct page *page = slab_page(slab);
502
503 VM_BUG_ON_PAGE(PageTail(page), page);
504 bit_spin_lock(PG_locked, &page->flags);
505}
506
507static __always_inline void slab_unlock(struct slab *slab)
508{
509 struct page *page = slab_page(slab);
510
511 VM_BUG_ON_PAGE(PageTail(page), page);
512 __bit_spin_unlock(PG_locked, &page->flags);
513}
514
515/*
516 * Interrupts must be disabled (for the fallback code to work right), typically
517 * by an _irqsave() lock variant. On PREEMPT_RT the preempt_disable(), which is
518 * part of bit_spin_lock(), is sufficient because the policy is not to allow any
519 * allocation/ free operation in hardirq context. Therefore nothing can
520 * interrupt the operation.
521 */
522static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
523 void *freelist_old, unsigned long counters_old,
524 void *freelist_new, unsigned long counters_new,
525 const char *n)
526{
527 if (USE_LOCKLESS_FAST_PATH())
528 lockdep_assert_irqs_disabled();
529#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
530 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
531 if (s->flags & __CMPXCHG_DOUBLE) {
532 if (cmpxchg_double(&slab->freelist, &slab->counters,
533 freelist_old, counters_old,
534 freelist_new, counters_new))
535 return true;
536 } else
537#endif
538 {
539 slab_lock(slab);
540 if (slab->freelist == freelist_old &&
541 slab->counters == counters_old) {
542 slab->freelist = freelist_new;
543 slab->counters = counters_new;
544 slab_unlock(slab);
545 return true;
546 }
547 slab_unlock(slab);
548 }
549
550 cpu_relax();
551 stat(s, CMPXCHG_DOUBLE_FAIL);
552
553#ifdef SLUB_DEBUG_CMPXCHG
554 pr_info("%s %s: cmpxchg double redo ", n, s->name);
555#endif
556
557 return false;
558}
559
560static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
561 void *freelist_old, unsigned long counters_old,
562 void *freelist_new, unsigned long counters_new,
563 const char *n)
564{
565#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
566 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
567 if (s->flags & __CMPXCHG_DOUBLE) {
568 if (cmpxchg_double(&slab->freelist, &slab->counters,
569 freelist_old, counters_old,
570 freelist_new, counters_new))
571 return true;
572 } else
573#endif
574 {
575 unsigned long flags;
576
577 local_irq_save(flags);
578 slab_lock(slab);
579 if (slab->freelist == freelist_old &&
580 slab->counters == counters_old) {
581 slab->freelist = freelist_new;
582 slab->counters = counters_new;
583 slab_unlock(slab);
584 local_irq_restore(flags);
585 return true;
586 }
587 slab_unlock(slab);
588 local_irq_restore(flags);
589 }
590
591 cpu_relax();
592 stat(s, CMPXCHG_DOUBLE_FAIL);
593
594#ifdef SLUB_DEBUG_CMPXCHG
595 pr_info("%s %s: cmpxchg double redo ", n, s->name);
596#endif
597
598 return false;
599}
600
601#ifdef CONFIG_SLUB_DEBUG
602static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
603static DEFINE_SPINLOCK(object_map_lock);
604
605static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
606 struct slab *slab)
607{
608 void *addr = slab_address(slab);
609 void *p;
610
611 bitmap_zero(obj_map, slab->objects);
612
613 for (p = slab->freelist; p; p = get_freepointer(s, p))
614 set_bit(__obj_to_index(s, addr, p), obj_map);
615}
616
617#if IS_ENABLED(CONFIG_KUNIT)
618static bool slab_add_kunit_errors(void)
619{
620 struct kunit_resource *resource;
621
622 if (!kunit_get_current_test())
623 return false;
624
625 resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
626 if (!resource)
627 return false;
628
629 (*(int *)resource->data)++;
630 kunit_put_resource(resource);
631 return true;
632}
633#else
634static inline bool slab_add_kunit_errors(void) { return false; }
635#endif
636
637static inline unsigned int size_from_object(struct kmem_cache *s)
638{
639 if (s->flags & SLAB_RED_ZONE)
640 return s->size - s->red_left_pad;
641
642 return s->size;
643}
644
645static inline void *restore_red_left(struct kmem_cache *s, void *p)
646{
647 if (s->flags & SLAB_RED_ZONE)
648 p -= s->red_left_pad;
649
650 return p;
651}
652
653/*
654 * Debug settings:
655 */
656#if defined(CONFIG_SLUB_DEBUG_ON)
657static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
658#else
659static slab_flags_t slub_debug;
660#endif
661
662static char *slub_debug_string;
663static int disable_higher_order_debug;
664
665/*
666 * slub is about to manipulate internal object metadata. This memory lies
667 * outside the range of the allocated object, so accessing it would normally
668 * be reported by kasan as a bounds error. metadata_access_enable() is used
669 * to tell kasan that these accesses are OK.
670 */
671static inline void metadata_access_enable(void)
672{
673 kasan_disable_current();
674}
675
676static inline void metadata_access_disable(void)
677{
678 kasan_enable_current();
679}
680
681/*
682 * Object debugging
683 */
684
685/* Verify that a pointer has an address that is valid within a slab page */
686static inline int check_valid_pointer(struct kmem_cache *s,
687 struct slab *slab, void *object)
688{
689 void *base;
690
691 if (!object)
692 return 1;
693
694 base = slab_address(slab);
695 object = kasan_reset_tag(object);
696 object = restore_red_left(s, object);
697 if (object < base || object >= base + slab->objects * s->size ||
698 (object - base) % s->size) {
699 return 0;
700 }
701
702 return 1;
703}
704
705static void print_section(char *level, char *text, u8 *addr,
706 unsigned int length)
707{
708 metadata_access_enable();
709 print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
710 16, 1, kasan_reset_tag((void *)addr), length, 1);
711 metadata_access_disable();
712}
713
714/*
715 * See comment in calculate_sizes().
716 */
717static inline bool freeptr_outside_object(struct kmem_cache *s)
718{
719 return s->offset >= s->inuse;
720}
721
722/*
723 * Return offset of the end of info block which is inuse + free pointer if
724 * not overlapping with object.
725 */
726static inline unsigned int get_info_end(struct kmem_cache *s)
727{
728 if (freeptr_outside_object(s))
729 return s->inuse + sizeof(void *);
730 else
731 return s->inuse;
732}
733
734static struct track *get_track(struct kmem_cache *s, void *object,
735 enum track_item alloc)
736{
737 struct track *p;
738
739 p = object + get_info_end(s);
740
741 return kasan_reset_tag(p + alloc);
742}
743
744#ifdef CONFIG_STACKDEPOT
745static noinline depot_stack_handle_t set_track_prepare(void)
746{
747 depot_stack_handle_t handle;
748 unsigned long entries[TRACK_ADDRS_COUNT];
749 unsigned int nr_entries;
750
751 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
752 handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
753
754 return handle;
755}
756#else
757static inline depot_stack_handle_t set_track_prepare(void)
758{
759 return 0;
760}
761#endif
762
763static void set_track_update(struct kmem_cache *s, void *object,
764 enum track_item alloc, unsigned long addr,
765 depot_stack_handle_t handle)
766{
767 struct track *p = get_track(s, object, alloc);
768
769#ifdef CONFIG_STACKDEPOT
770 p->handle = handle;
771#endif
772 p->addr = addr;
773 p->cpu = smp_processor_id();
774 p->pid = current->pid;
775 p->when = jiffies;
776}
777
778static __always_inline void set_track(struct kmem_cache *s, void *object,
779 enum track_item alloc, unsigned long addr)
780{
781 depot_stack_handle_t handle = set_track_prepare();
782
783 set_track_update(s, object, alloc, addr, handle);
784}
785
786static void init_tracking(struct kmem_cache *s, void *object)
787{
788 struct track *p;
789
790 if (!(s->flags & SLAB_STORE_USER))
791 return;
792
793 p = get_track(s, object, TRACK_ALLOC);
794 memset(p, 0, 2*sizeof(struct track));
795}
796
797static void print_track(const char *s, struct track *t, unsigned long pr_time)
798{
799 depot_stack_handle_t handle __maybe_unused;
800
801 if (!t->addr)
802 return;
803
804 pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
805 s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
806#ifdef CONFIG_STACKDEPOT
807 handle = READ_ONCE(t->handle);
808 if (handle)
809 stack_depot_print(handle);
810 else
811 pr_err("object allocation/free stack trace missing\n");
812#endif
813}
814
815void print_tracking(struct kmem_cache *s, void *object)
816{
817 unsigned long pr_time = jiffies;
818 if (!(s->flags & SLAB_STORE_USER))
819 return;
820
821 print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
822 print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
823}
824
825static void print_slab_info(const struct slab *slab)
826{
827 struct folio *folio = (struct folio *)slab_folio(slab);
828
829 pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
830 slab, slab->objects, slab->inuse, slab->freelist,
831 folio_flags(folio, 0));
832}
833
834/*
835 * kmalloc caches has fixed sizes (mostly power of 2), and kmalloc() API
836 * family will round up the real request size to these fixed ones, so
837 * there could be an extra area than what is requested. Save the original
838 * request size in the meta data area, for better debug and sanity check.
839 */
840static inline void set_orig_size(struct kmem_cache *s,
841 void *object, unsigned int orig_size)
842{
843 void *p = kasan_reset_tag(object);
844
845 if (!slub_debug_orig_size(s))
846 return;
847
848#ifdef CONFIG_KASAN_GENERIC
849 /*
850 * KASAN could save its free meta data in object's data area at
851 * offset 0, if the size is larger than 'orig_size', it will
852 * overlap the data redzone in [orig_size+1, object_size], and
853 * the check should be skipped.
854 */
855 if (kasan_metadata_size(s, true) > orig_size)
856 orig_size = s->object_size;
857#endif
858
859 p += get_info_end(s);
860 p += sizeof(struct track) * 2;
861
862 *(unsigned int *)p = orig_size;
863}
864
865static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
866{
867 void *p = kasan_reset_tag(object);
868
869 if (!slub_debug_orig_size(s))
870 return s->object_size;
871
872 p += get_info_end(s);
873 p += sizeof(struct track) * 2;
874
875 return *(unsigned int *)p;
876}
877
878void skip_orig_size_check(struct kmem_cache *s, const void *object)
879{
880 set_orig_size(s, (void *)object, s->object_size);
881}
882
883static void slab_bug(struct kmem_cache *s, char *fmt, ...)
884{
885 struct va_format vaf;
886 va_list args;
887
888 va_start(args, fmt);
889 vaf.fmt = fmt;
890 vaf.va = &args;
891 pr_err("=============================================================================\n");
892 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
893 pr_err("-----------------------------------------------------------------------------\n\n");
894 va_end(args);
895}
896
897__printf(2, 3)
898static void slab_fix(struct kmem_cache *s, char *fmt, ...)
899{
900 struct va_format vaf;
901 va_list args;
902
903 if (slab_add_kunit_errors())
904 return;
905
906 va_start(args, fmt);
907 vaf.fmt = fmt;
908 vaf.va = &args;
909 pr_err("FIX %s: %pV\n", s->name, &vaf);
910 va_end(args);
911}
912
913static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
914{
915 unsigned int off; /* Offset of last byte */
916 u8 *addr = slab_address(slab);
917
918 print_tracking(s, p);
919
920 print_slab_info(slab);
921
922 pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
923 p, p - addr, get_freepointer(s, p));
924
925 if (s->flags & SLAB_RED_ZONE)
926 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
927 s->red_left_pad);
928 else if (p > addr + 16)
929 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
930
931 print_section(KERN_ERR, "Object ", p,
932 min_t(unsigned int, s->object_size, PAGE_SIZE));
933 if (s->flags & SLAB_RED_ZONE)
934 print_section(KERN_ERR, "Redzone ", p + s->object_size,
935 s->inuse - s->object_size);
936
937 off = get_info_end(s);
938
939 if (s->flags & SLAB_STORE_USER)
940 off += 2 * sizeof(struct track);
941
942 if (slub_debug_orig_size(s))
943 off += sizeof(unsigned int);
944
945 off += kasan_metadata_size(s, false);
946
947 if (off != size_from_object(s))
948 /* Beginning of the filler is the free pointer */
949 print_section(KERN_ERR, "Padding ", p + off,
950 size_from_object(s) - off);
951
952 dump_stack();
953}
954
955static void object_err(struct kmem_cache *s, struct slab *slab,
956 u8 *object, char *reason)
957{
958 if (slab_add_kunit_errors())
959 return;
960
961 slab_bug(s, "%s", reason);
962 print_trailer(s, slab, object);
963 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
964}
965
966static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
967 void **freelist, void *nextfree)
968{
969 if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
970 !check_valid_pointer(s, slab, nextfree) && freelist) {
971 object_err(s, slab, *freelist, "Freechain corrupt");
972 *freelist = NULL;
973 slab_fix(s, "Isolate corrupted freechain");
974 return true;
975 }
976
977 return false;
978}
979
980static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
981 const char *fmt, ...)
982{
983 va_list args;
984 char buf[100];
985
986 if (slab_add_kunit_errors())
987 return;
988
989 va_start(args, fmt);
990 vsnprintf(buf, sizeof(buf), fmt, args);
991 va_end(args);
992 slab_bug(s, "%s", buf);
993 print_slab_info(slab);
994 dump_stack();
995 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
996}
997
998static void init_object(struct kmem_cache *s, void *object, u8 val)
999{
1000 u8 *p = kasan_reset_tag(object);
1001 unsigned int poison_size = s->object_size;
1002
1003 if (s->flags & SLAB_RED_ZONE) {
1004 memset(p - s->red_left_pad, val, s->red_left_pad);
1005
1006 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1007 /*
1008 * Redzone the extra allocated space by kmalloc than
1009 * requested, and the poison size will be limited to
1010 * the original request size accordingly.
1011 */
1012 poison_size = get_orig_size(s, object);
1013 }
1014 }
1015
1016 if (s->flags & __OBJECT_POISON) {
1017 memset(p, POISON_FREE, poison_size - 1);
1018 p[poison_size - 1] = POISON_END;
1019 }
1020
1021 if (s->flags & SLAB_RED_ZONE)
1022 memset(p + poison_size, val, s->inuse - poison_size);
1023}
1024
1025static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
1026 void *from, void *to)
1027{
1028 slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
1029 memset(from, data, to - from);
1030}
1031
1032static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
1033 u8 *object, char *what,
1034 u8 *start, unsigned int value, unsigned int bytes)
1035{
1036 u8 *fault;
1037 u8 *end;
1038 u8 *addr = slab_address(slab);
1039
1040 metadata_access_enable();
1041 fault = memchr_inv(kasan_reset_tag(start), value, bytes);
1042 metadata_access_disable();
1043 if (!fault)
1044 return 1;
1045
1046 end = start + bytes;
1047 while (end > fault && end[-1] == value)
1048 end--;
1049
1050 if (slab_add_kunit_errors())
1051 goto skip_bug_print;
1052
1053 slab_bug(s, "%s overwritten", what);
1054 pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
1055 fault, end - 1, fault - addr,
1056 fault[0], value);
1057 print_trailer(s, slab, object);
1058 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1059
1060skip_bug_print:
1061 restore_bytes(s, what, value, fault, end);
1062 return 0;
1063}
1064
1065/*
1066 * Object layout:
1067 *
1068 * object address
1069 * Bytes of the object to be managed.
1070 * If the freepointer may overlay the object then the free
1071 * pointer is at the middle of the object.
1072 *
1073 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
1074 * 0xa5 (POISON_END)
1075 *
1076 * object + s->object_size
1077 * Padding to reach word boundary. This is also used for Redzoning.
1078 * Padding is extended by another word if Redzoning is enabled and
1079 * object_size == inuse.
1080 *
1081 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
1082 * 0xcc (RED_ACTIVE) for objects in use.
1083 *
1084 * object + s->inuse
1085 * Meta data starts here.
1086 *
1087 * A. Free pointer (if we cannot overwrite object on free)
1088 * B. Tracking data for SLAB_STORE_USER
1089 * C. Original request size for kmalloc object (SLAB_STORE_USER enabled)
1090 * D. Padding to reach required alignment boundary or at minimum
1091 * one word if debugging is on to be able to detect writes
1092 * before the word boundary.
1093 *
1094 * Padding is done using 0x5a (POISON_INUSE)
1095 *
1096 * object + s->size
1097 * Nothing is used beyond s->size.
1098 *
1099 * If slabcaches are merged then the object_size and inuse boundaries are mostly
1100 * ignored. And therefore no slab options that rely on these boundaries
1101 * may be used with merged slabcaches.
1102 */
1103
1104static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
1105{
1106 unsigned long off = get_info_end(s); /* The end of info */
1107
1108 if (s->flags & SLAB_STORE_USER) {
1109 /* We also have user information there */
1110 off += 2 * sizeof(struct track);
1111
1112 if (s->flags & SLAB_KMALLOC)
1113 off += sizeof(unsigned int);
1114 }
1115
1116 off += kasan_metadata_size(s, false);
1117
1118 if (size_from_object(s) == off)
1119 return 1;
1120
1121 return check_bytes_and_report(s, slab, p, "Object padding",
1122 p + off, POISON_INUSE, size_from_object(s) - off);
1123}
1124
1125/* Check the pad bytes at the end of a slab page */
1126static void slab_pad_check(struct kmem_cache *s, struct slab *slab)
1127{
1128 u8 *start;
1129 u8 *fault;
1130 u8 *end;
1131 u8 *pad;
1132 int length;
1133 int remainder;
1134
1135 if (!(s->flags & SLAB_POISON))
1136 return;
1137
1138 start = slab_address(slab);
1139 length = slab_size(slab);
1140 end = start + length;
1141 remainder = length % s->size;
1142 if (!remainder)
1143 return;
1144
1145 pad = end - remainder;
1146 metadata_access_enable();
1147 fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
1148 metadata_access_disable();
1149 if (!fault)
1150 return;
1151 while (end > fault && end[-1] == POISON_INUSE)
1152 end--;
1153
1154 slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
1155 fault, end - 1, fault - start);
1156 print_section(KERN_ERR, "Padding ", pad, remainder);
1157
1158 restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
1159}
1160
1161static int check_object(struct kmem_cache *s, struct slab *slab,
1162 void *object, u8 val)
1163{
1164 u8 *p = object;
1165 u8 *endobject = object + s->object_size;
1166 unsigned int orig_size;
1167
1168 if (s->flags & SLAB_RED_ZONE) {
1169 if (!check_bytes_and_report(s, slab, object, "Left Redzone",
1170 object - s->red_left_pad, val, s->red_left_pad))
1171 return 0;
1172
1173 if (!check_bytes_and_report(s, slab, object, "Right Redzone",
1174 endobject, val, s->inuse - s->object_size))
1175 return 0;
1176
1177 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1178 orig_size = get_orig_size(s, object);
1179
1180 if (s->object_size > orig_size &&
1181 !check_bytes_and_report(s, slab, object,
1182 "kmalloc Redzone", p + orig_size,
1183 val, s->object_size - orig_size)) {
1184 return 0;
1185 }
1186 }
1187 } else {
1188 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
1189 check_bytes_and_report(s, slab, p, "Alignment padding",
1190 endobject, POISON_INUSE,
1191 s->inuse - s->object_size);
1192 }
1193 }
1194
1195 if (s->flags & SLAB_POISON) {
1196 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
1197 (!check_bytes_and_report(s, slab, p, "Poison", p,
1198 POISON_FREE, s->object_size - 1) ||
1199 !check_bytes_and_report(s, slab, p, "End Poison",
1200 p + s->object_size - 1, POISON_END, 1)))
1201 return 0;
1202 /*
1203 * check_pad_bytes cleans up on its own.
1204 */
1205 check_pad_bytes(s, slab, p);
1206 }
1207
1208 if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
1209 /*
1210 * Object and freepointer overlap. Cannot check
1211 * freepointer while object is allocated.
1212 */
1213 return 1;
1214
1215 /* Check free pointer validity */
1216 if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
1217 object_err(s, slab, p, "Freepointer corrupt");
1218 /*
1219 * No choice but to zap it and thus lose the remainder
1220 * of the free objects in this slab. May cause
1221 * another error because the object count is now wrong.
1222 */
1223 set_freepointer(s, p, NULL);
1224 return 0;
1225 }
1226 return 1;
1227}
1228
1229static int check_slab(struct kmem_cache *s, struct slab *slab)
1230{
1231 int maxobj;
1232
1233 if (!folio_test_slab(slab_folio(slab))) {
1234 slab_err(s, slab, "Not a valid slab page");
1235 return 0;
1236 }
1237
1238 maxobj = order_objects(slab_order(slab), s->size);
1239 if (slab->objects > maxobj) {
1240 slab_err(s, slab, "objects %u > max %u",
1241 slab->objects, maxobj);
1242 return 0;
1243 }
1244 if (slab->inuse > slab->objects) {
1245 slab_err(s, slab, "inuse %u > max %u",
1246 slab->inuse, slab->objects);
1247 return 0;
1248 }
1249 /* Slab_pad_check fixes things up after itself */
1250 slab_pad_check(s, slab);
1251 return 1;
1252}
1253
1254/*
1255 * Determine if a certain object in a slab is on the freelist. Must hold the
1256 * slab lock to guarantee that the chains are in a consistent state.
1257 */
1258static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
1259{
1260 int nr = 0;
1261 void *fp;
1262 void *object = NULL;
1263 int max_objects;
1264
1265 fp = slab->freelist;
1266 while (fp && nr <= slab->objects) {
1267 if (fp == search)
1268 return 1;
1269 if (!check_valid_pointer(s, slab, fp)) {
1270 if (object) {
1271 object_err(s, slab, object,
1272 "Freechain corrupt");
1273 set_freepointer(s, object, NULL);
1274 } else {
1275 slab_err(s, slab, "Freepointer corrupt");
1276 slab->freelist = NULL;
1277 slab->inuse = slab->objects;
1278 slab_fix(s, "Freelist cleared");
1279 return 0;
1280 }
1281 break;
1282 }
1283 object = fp;
1284 fp = get_freepointer(s, object);
1285 nr++;
1286 }
1287
1288 max_objects = order_objects(slab_order(slab), s->size);
1289 if (max_objects > MAX_OBJS_PER_PAGE)
1290 max_objects = MAX_OBJS_PER_PAGE;
1291
1292 if (slab->objects != max_objects) {
1293 slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
1294 slab->objects, max_objects);
1295 slab->objects = max_objects;
1296 slab_fix(s, "Number of objects adjusted");
1297 }
1298 if (slab->inuse != slab->objects - nr) {
1299 slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
1300 slab->inuse, slab->objects - nr);
1301 slab->inuse = slab->objects - nr;
1302 slab_fix(s, "Object count adjusted");
1303 }
1304 return search == NULL;
1305}
1306
1307static void trace(struct kmem_cache *s, struct slab *slab, void *object,
1308 int alloc)
1309{
1310 if (s->flags & SLAB_TRACE) {
1311 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1312 s->name,
1313 alloc ? "alloc" : "free",
1314 object, slab->inuse,
1315 slab->freelist);
1316
1317 if (!alloc)
1318 print_section(KERN_INFO, "Object ", (void *)object,
1319 s->object_size);
1320
1321 dump_stack();
1322 }
1323}
1324
1325/*
1326 * Tracking of fully allocated slabs for debugging purposes.
1327 */
1328static void add_full(struct kmem_cache *s,
1329 struct kmem_cache_node *n, struct slab *slab)
1330{
1331 if (!(s->flags & SLAB_STORE_USER))
1332 return;
1333
1334 lockdep_assert_held(&n->list_lock);
1335 list_add(&slab->slab_list, &n->full);
1336}
1337
1338static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
1339{
1340 if (!(s->flags & SLAB_STORE_USER))
1341 return;
1342
1343 lockdep_assert_held(&n->list_lock);
1344 list_del(&slab->slab_list);
1345}
1346
1347/* Tracking of the number of slabs for debugging purposes */
1348static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1349{
1350 struct kmem_cache_node *n = get_node(s, node);
1351
1352 return atomic_long_read(&n->nr_slabs);
1353}
1354
1355static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1356{
1357 return atomic_long_read(&n->nr_slabs);
1358}
1359
1360static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1361{
1362 struct kmem_cache_node *n = get_node(s, node);
1363
1364 /*
1365 * May be called early in order to allocate a slab for the
1366 * kmem_cache_node structure. Solve the chicken-egg
1367 * dilemma by deferring the increment of the count during
1368 * bootstrap (see early_kmem_cache_node_alloc).
1369 */
1370 if (likely(n)) {
1371 atomic_long_inc(&n->nr_slabs);
1372 atomic_long_add(objects, &n->total_objects);
1373 }
1374}
1375static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1376{
1377 struct kmem_cache_node *n = get_node(s, node);
1378
1379 atomic_long_dec(&n->nr_slabs);
1380 atomic_long_sub(objects, &n->total_objects);
1381}
1382
1383/* Object debug checks for alloc/free paths */
1384static void setup_object_debug(struct kmem_cache *s, void *object)
1385{
1386 if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
1387 return;
1388
1389 init_object(s, object, SLUB_RED_INACTIVE);
1390 init_tracking(s, object);
1391}
1392
1393static
1394void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
1395{
1396 if (!kmem_cache_debug_flags(s, SLAB_POISON))
1397 return;
1398
1399 metadata_access_enable();
1400 memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
1401 metadata_access_disable();
1402}
1403
1404static inline int alloc_consistency_checks(struct kmem_cache *s,
1405 struct slab *slab, void *object)
1406{
1407 if (!check_slab(s, slab))
1408 return 0;
1409
1410 if (!check_valid_pointer(s, slab, object)) {
1411 object_err(s, slab, object, "Freelist Pointer check fails");
1412 return 0;
1413 }
1414
1415 if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
1416 return 0;
1417
1418 return 1;
1419}
1420
1421static noinline bool alloc_debug_processing(struct kmem_cache *s,
1422 struct slab *slab, void *object, int orig_size)
1423{
1424 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1425 if (!alloc_consistency_checks(s, slab, object))
1426 goto bad;
1427 }
1428
1429 /* Success. Perform special debug activities for allocs */
1430 trace(s, slab, object, 1);
1431 set_orig_size(s, object, orig_size);
1432 init_object(s, object, SLUB_RED_ACTIVE);
1433 return true;
1434
1435bad:
1436 if (folio_test_slab(slab_folio(slab))) {
1437 /*
1438 * If this is a slab page then lets do the best we can
1439 * to avoid issues in the future. Marking all objects
1440 * as used avoids touching the remaining objects.
1441 */
1442 slab_fix(s, "Marking all objects used");
1443 slab->inuse = slab->objects;
1444 slab->freelist = NULL;
1445 }
1446 return false;
1447}
1448
1449static inline int free_consistency_checks(struct kmem_cache *s,
1450 struct slab *slab, void *object, unsigned long addr)
1451{
1452 if (!check_valid_pointer(s, slab, object)) {
1453 slab_err(s, slab, "Invalid object pointer 0x%p", object);
1454 return 0;
1455 }
1456
1457 if (on_freelist(s, slab, object)) {
1458 object_err(s, slab, object, "Object already free");
1459 return 0;
1460 }
1461
1462 if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
1463 return 0;
1464
1465 if (unlikely(s != slab->slab_cache)) {
1466 if (!folio_test_slab(slab_folio(slab))) {
1467 slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
1468 object);
1469 } else if (!slab->slab_cache) {
1470 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1471 object);
1472 dump_stack();
1473 } else
1474 object_err(s, slab, object,
1475 "page slab pointer corrupt.");
1476 return 0;
1477 }
1478 return 1;
1479}
1480
1481/*
1482 * Parse a block of slub_debug options. Blocks are delimited by ';'
1483 *
1484 * @str: start of block
1485 * @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1486 * @slabs: return start of list of slabs, or NULL when there's no list
1487 * @init: assume this is initial parsing and not per-kmem-create parsing
1488 *
1489 * returns the start of next block if there's any, or NULL
1490 */
1491static char *
1492parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
1493{
1494 bool higher_order_disable = false;
1495
1496 /* Skip any completely empty blocks */
1497 while (*str && *str == ';')
1498 str++;
1499
1500 if (*str == ',') {
1501 /*
1502 * No options but restriction on slabs. This means full
1503 * debugging for slabs matching a pattern.
1504 */
1505 *flags = DEBUG_DEFAULT_FLAGS;
1506 goto check_slabs;
1507 }
1508 *flags = 0;
1509
1510 /* Determine which debug features should be switched on */
1511 for (; *str && *str != ',' && *str != ';'; str++) {
1512 switch (tolower(*str)) {
1513 case '-':
1514 *flags = 0;
1515 break;
1516 case 'f':
1517 *flags |= SLAB_CONSISTENCY_CHECKS;
1518 break;
1519 case 'z':
1520 *flags |= SLAB_RED_ZONE;
1521 break;
1522 case 'p':
1523 *flags |= SLAB_POISON;
1524 break;
1525 case 'u':
1526 *flags |= SLAB_STORE_USER;
1527 break;
1528 case 't':
1529 *flags |= SLAB_TRACE;
1530 break;
1531 case 'a':
1532 *flags |= SLAB_FAILSLAB;
1533 break;
1534 case 'o':
1535 /*
1536 * Avoid enabling debugging on caches if its minimum
1537 * order would increase as a result.
1538 */
1539 higher_order_disable = true;
1540 break;
1541 default:
1542 if (init)
1543 pr_err("slub_debug option '%c' unknown. skipped\n", *str);
1544 }
1545 }
1546check_slabs:
1547 if (*str == ',')
1548 *slabs = ++str;
1549 else
1550 *slabs = NULL;
1551
1552 /* Skip over the slab list */
1553 while (*str && *str != ';')
1554 str++;
1555
1556 /* Skip any completely empty blocks */
1557 while (*str && *str == ';')
1558 str++;
1559
1560 if (init && higher_order_disable)
1561 disable_higher_order_debug = 1;
1562
1563 if (*str)
1564 return str;
1565 else
1566 return NULL;
1567}
1568
1569static int __init setup_slub_debug(char *str)
1570{
1571 slab_flags_t flags;
1572 slab_flags_t global_flags;
1573 char *saved_str;
1574 char *slab_list;
1575 bool global_slub_debug_changed = false;
1576 bool slab_list_specified = false;
1577
1578 global_flags = DEBUG_DEFAULT_FLAGS;
1579 if (*str++ != '=' || !*str)
1580 /*
1581 * No options specified. Switch on full debugging.
1582 */
1583 goto out;
1584
1585 saved_str = str;
1586 while (str) {
1587 str = parse_slub_debug_flags(str, &flags, &slab_list, true);
1588
1589 if (!slab_list) {
1590 global_flags = flags;
1591 global_slub_debug_changed = true;
1592 } else {
1593 slab_list_specified = true;
1594 if (flags & SLAB_STORE_USER)
1595 stack_depot_want_early_init();
1596 }
1597 }
1598
1599 /*
1600 * For backwards compatibility, a single list of flags with list of
1601 * slabs means debugging is only changed for those slabs, so the global
1602 * slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
1603 * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
1604 * long as there is no option specifying flags without a slab list.
1605 */
1606 if (slab_list_specified) {
1607 if (!global_slub_debug_changed)
1608 global_flags = slub_debug;
1609 slub_debug_string = saved_str;
1610 }
1611out:
1612 slub_debug = global_flags;
1613 if (slub_debug & SLAB_STORE_USER)
1614 stack_depot_want_early_init();
1615 if (slub_debug != 0 || slub_debug_string)
1616 static_branch_enable(&slub_debug_enabled);
1617 else
1618 static_branch_disable(&slub_debug_enabled);
1619 if ((static_branch_unlikely(&init_on_alloc) ||
1620 static_branch_unlikely(&init_on_free)) &&
1621 (slub_debug & SLAB_POISON))
1622 pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1623 return 1;
1624}
1625
1626__setup("slub_debug", setup_slub_debug);
1627
1628/*
1629 * kmem_cache_flags - apply debugging options to the cache
1630 * @object_size: the size of an object without meta data
1631 * @flags: flags to set
1632 * @name: name of the cache
1633 *
1634 * Debug option(s) are applied to @flags. In addition to the debug
1635 * option(s), if a slab name (or multiple) is specified i.e.
1636 * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1637 * then only the select slabs will receive the debug option(s).
1638 */
1639slab_flags_t kmem_cache_flags(unsigned int object_size,
1640 slab_flags_t flags, const char *name)
1641{
1642 char *iter;
1643 size_t len;
1644 char *next_block;
1645 slab_flags_t block_flags;
1646 slab_flags_t slub_debug_local = slub_debug;
1647
1648 if (flags & SLAB_NO_USER_FLAGS)
1649 return flags;
1650
1651 /*
1652 * If the slab cache is for debugging (e.g. kmemleak) then
1653 * don't store user (stack trace) information by default,
1654 * but let the user enable it via the command line below.
1655 */
1656 if (flags & SLAB_NOLEAKTRACE)
1657 slub_debug_local &= ~SLAB_STORE_USER;
1658
1659 len = strlen(name);
1660 next_block = slub_debug_string;
1661 /* Go through all blocks of debug options, see if any matches our slab's name */
1662 while (next_block) {
1663 next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
1664 if (!iter)
1665 continue;
1666 /* Found a block that has a slab list, search it */
1667 while (*iter) {
1668 char *end, *glob;
1669 size_t cmplen;
1670
1671 end = strchrnul(iter, ',');
1672 if (next_block && next_block < end)
1673 end = next_block - 1;
1674
1675 glob = strnchr(iter, end - iter, '*');
1676 if (glob)
1677 cmplen = glob - iter;
1678 else
1679 cmplen = max_t(size_t, len, (end - iter));
1680
1681 if (!strncmp(name, iter, cmplen)) {
1682 flags |= block_flags;
1683 return flags;
1684 }
1685
1686 if (!*end || *end == ';')
1687 break;
1688 iter = end + 1;
1689 }
1690 }
1691
1692 return flags | slub_debug_local;
1693}
1694#else /* !CONFIG_SLUB_DEBUG */
1695static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
1696static inline
1697void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
1698
1699static inline bool alloc_debug_processing(struct kmem_cache *s,
1700 struct slab *slab, void *object, int orig_size) { return true; }
1701
1702static inline bool free_debug_processing(struct kmem_cache *s,
1703 struct slab *slab, void *head, void *tail, int *bulk_cnt,
1704 unsigned long addr, depot_stack_handle_t handle) { return true; }
1705
1706static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
1707static inline int check_object(struct kmem_cache *s, struct slab *slab,
1708 void *object, u8 val) { return 1; }
1709static inline depot_stack_handle_t set_track_prepare(void) { return 0; }
1710static inline void set_track(struct kmem_cache *s, void *object,
1711 enum track_item alloc, unsigned long addr) {}
1712static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1713 struct slab *slab) {}
1714static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1715 struct slab *slab) {}
1716slab_flags_t kmem_cache_flags(unsigned int object_size,
1717 slab_flags_t flags, const char *name)
1718{
1719 return flags;
1720}
1721#define slub_debug 0
1722
1723#define disable_higher_order_debug 0
1724
1725static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1726 { return 0; }
1727static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1728 { return 0; }
1729static inline void inc_slabs_node(struct kmem_cache *s, int node,
1730 int objects) {}
1731static inline void dec_slabs_node(struct kmem_cache *s, int node,
1732 int objects) {}
1733
1734#ifndef CONFIG_SLUB_TINY
1735static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1736 void **freelist, void *nextfree)
1737{
1738 return false;
1739}
1740#endif
1741#endif /* CONFIG_SLUB_DEBUG */
1742
1743/*
1744 * Hooks for other subsystems that check memory allocations. In a typical
1745 * production configuration these hooks all should produce no code at all.
1746 */
1747static __always_inline bool slab_free_hook(struct kmem_cache *s,
1748 void *x, bool init)
1749{
1750 kmemleak_free_recursive(x, s->flags);
1751 kmsan_slab_free(s, x);
1752
1753 debug_check_no_locks_freed(x, s->object_size);
1754
1755 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1756 debug_check_no_obj_freed(x, s->object_size);
1757
1758 /* Use KCSAN to help debug racy use-after-free. */
1759 if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
1760 __kcsan_check_access(x, s->object_size,
1761 KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
1762
1763 /*
1764 * As memory initialization might be integrated into KASAN,
1765 * kasan_slab_free and initialization memset's must be
1766 * kept together to avoid discrepancies in behavior.
1767 *
1768 * The initialization memset's clear the object and the metadata,
1769 * but don't touch the SLAB redzone.
1770 */
1771 if (init) {
1772 int rsize;
1773
1774 if (!kasan_has_integrated_init())
1775 memset(kasan_reset_tag(x), 0, s->object_size);
1776 rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
1777 memset((char *)kasan_reset_tag(x) + s->inuse, 0,
1778 s->size - s->inuse - rsize);
1779 }
1780 /* KASAN might put x into memory quarantine, delaying its reuse. */
1781 return kasan_slab_free(s, x, init);
1782}
1783
1784static inline bool slab_free_freelist_hook(struct kmem_cache *s,
1785 void **head, void **tail,
1786 int *cnt)
1787{
1788
1789 void *object;
1790 void *next = *head;
1791 void *old_tail = *tail ? *tail : *head;
1792
1793 if (is_kfence_address(next)) {
1794 slab_free_hook(s, next, false);
1795 return true;
1796 }
1797
1798 /* Head and tail of the reconstructed freelist */
1799 *head = NULL;
1800 *tail = NULL;
1801
1802 do {
1803 object = next;
1804 next = get_freepointer(s, object);
1805
1806 /* If object's reuse doesn't have to be delayed */
1807 if (!slab_free_hook(s, object, slab_want_init_on_free(s))) {
1808 /* Move object to the new freelist */
1809 set_freepointer(s, object, *head);
1810 *head = object;
1811 if (!*tail)
1812 *tail = object;
1813 } else {
1814 /*
1815 * Adjust the reconstructed freelist depth
1816 * accordingly if object's reuse is delayed.
1817 */
1818 --(*cnt);
1819 }
1820 } while (object != old_tail);
1821
1822 if (*head == *tail)
1823 *tail = NULL;
1824
1825 return *head != NULL;
1826}
1827
1828static void *setup_object(struct kmem_cache *s, void *object)
1829{
1830 setup_object_debug(s, object);
1831 object = kasan_init_slab_obj(s, object);
1832 if (unlikely(s->ctor)) {
1833 kasan_unpoison_object_data(s, object);
1834 s->ctor(object);
1835 kasan_poison_object_data(s, object);
1836 }
1837 return object;
1838}
1839
1840/*
1841 * Slab allocation and freeing
1842 */
1843static inline struct slab *alloc_slab_page(gfp_t flags, int node,
1844 struct kmem_cache_order_objects oo)
1845{
1846 struct folio *folio;
1847 struct slab *slab;
1848 unsigned int order = oo_order(oo);
1849
1850 if (node == NUMA_NO_NODE)
1851 folio = (struct folio *)alloc_pages(flags, order);
1852 else
1853 folio = (struct folio *)__alloc_pages_node(node, flags, order);
1854
1855 if (!folio)
1856 return NULL;
1857
1858 slab = folio_slab(folio);
1859 __folio_set_slab(folio);
1860 /* Make the flag visible before any changes to folio->mapping */
1861 smp_wmb();
1862 if (page_is_pfmemalloc(folio_page(folio, 0)))
1863 slab_set_pfmemalloc(slab);
1864
1865 return slab;
1866}
1867
1868#ifdef CONFIG_SLAB_FREELIST_RANDOM
1869/* Pre-initialize the random sequence cache */
1870static int init_cache_random_seq(struct kmem_cache *s)
1871{
1872 unsigned int count = oo_objects(s->oo);
1873 int err;
1874
1875 /* Bailout if already initialised */
1876 if (s->random_seq)
1877 return 0;
1878
1879 err = cache_random_seq_create(s, count, GFP_KERNEL);
1880 if (err) {
1881 pr_err("SLUB: Unable to initialize free list for %s\n",
1882 s->name);
1883 return err;
1884 }
1885
1886 /* Transform to an offset on the set of pages */
1887 if (s->random_seq) {
1888 unsigned int i;
1889
1890 for (i = 0; i < count; i++)
1891 s->random_seq[i] *= s->size;
1892 }
1893 return 0;
1894}
1895
1896/* Initialize each random sequence freelist per cache */
1897static void __init init_freelist_randomization(void)
1898{
1899 struct kmem_cache *s;
1900
1901 mutex_lock(&slab_mutex);
1902
1903 list_for_each_entry(s, &slab_caches, list)
1904 init_cache_random_seq(s);
1905
1906 mutex_unlock(&slab_mutex);
1907}
1908
1909/* Get the next entry on the pre-computed freelist randomized */
1910static void *next_freelist_entry(struct kmem_cache *s, struct slab *slab,
1911 unsigned long *pos, void *start,
1912 unsigned long page_limit,
1913 unsigned long freelist_count)
1914{
1915 unsigned int idx;
1916
1917 /*
1918 * If the target page allocation failed, the number of objects on the
1919 * page might be smaller than the usual size defined by the cache.
1920 */
1921 do {
1922 idx = s->random_seq[*pos];
1923 *pos += 1;
1924 if (*pos >= freelist_count)
1925 *pos = 0;
1926 } while (unlikely(idx >= page_limit));
1927
1928 return (char *)start + idx;
1929}
1930
1931/* Shuffle the single linked freelist based on a random pre-computed sequence */
1932static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
1933{
1934 void *start;
1935 void *cur;
1936 void *next;
1937 unsigned long idx, pos, page_limit, freelist_count;
1938
1939 if (slab->objects < 2 || !s->random_seq)
1940 return false;
1941
1942 freelist_count = oo_objects(s->oo);
1943 pos = get_random_u32_below(freelist_count);
1944
1945 page_limit = slab->objects * s->size;
1946 start = fixup_red_left(s, slab_address(slab));
1947
1948 /* First entry is used as the base of the freelist */
1949 cur = next_freelist_entry(s, slab, &pos, start, page_limit,
1950 freelist_count);
1951 cur = setup_object(s, cur);
1952 slab->freelist = cur;
1953
1954 for (idx = 1; idx < slab->objects; idx++) {
1955 next = next_freelist_entry(s, slab, &pos, start, page_limit,
1956 freelist_count);
1957 next = setup_object(s, next);
1958 set_freepointer(s, cur, next);
1959 cur = next;
1960 }
1961 set_freepointer(s, cur, NULL);
1962
1963 return true;
1964}
1965#else
1966static inline int init_cache_random_seq(struct kmem_cache *s)
1967{
1968 return 0;
1969}
1970static inline void init_freelist_randomization(void) { }
1971static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
1972{
1973 return false;
1974}
1975#endif /* CONFIG_SLAB_FREELIST_RANDOM */
1976
1977static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1978{
1979 struct slab *slab;
1980 struct kmem_cache_order_objects oo = s->oo;
1981 gfp_t alloc_gfp;
1982 void *start, *p, *next;
1983 int idx;
1984 bool shuffle;
1985
1986 flags &= gfp_allowed_mask;
1987
1988 flags |= s->allocflags;
1989
1990 /*
1991 * Let the initial higher-order allocation fail under memory pressure
1992 * so we fall-back to the minimum order allocation.
1993 */
1994 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1995 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1996 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
1997
1998 slab = alloc_slab_page(alloc_gfp, node, oo);
1999 if (unlikely(!slab)) {
2000 oo = s->min;
2001 alloc_gfp = flags;
2002 /*
2003 * Allocation may have failed due to fragmentation.
2004 * Try a lower order alloc if possible
2005 */
2006 slab = alloc_slab_page(alloc_gfp, node, oo);
2007 if (unlikely(!slab))
2008 return NULL;
2009 stat(s, ORDER_FALLBACK);
2010 }
2011
2012 slab->objects = oo_objects(oo);
2013 slab->inuse = 0;
2014 slab->frozen = 0;
2015
2016 account_slab(slab, oo_order(oo), s, flags);
2017
2018 slab->slab_cache = s;
2019
2020 kasan_poison_slab(slab);
2021
2022 start = slab_address(slab);
2023
2024 setup_slab_debug(s, slab, start);
2025
2026 shuffle = shuffle_freelist(s, slab);
2027
2028 if (!shuffle) {
2029 start = fixup_red_left(s, start);
2030 start = setup_object(s, start);
2031 slab->freelist = start;
2032 for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
2033 next = p + s->size;
2034 next = setup_object(s, next);
2035 set_freepointer(s, p, next);
2036 p = next;
2037 }
2038 set_freepointer(s, p, NULL);
2039 }
2040
2041 return slab;
2042}
2043
2044static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
2045{
2046 if (unlikely(flags & GFP_SLAB_BUG_MASK))
2047 flags = kmalloc_fix_flags(flags);
2048
2049 WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2050
2051 return allocate_slab(s,
2052 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
2053}
2054
2055static void __free_slab(struct kmem_cache *s, struct slab *slab)
2056{
2057 struct folio *folio = slab_folio(slab);
2058 int order = folio_order(folio);
2059 int pages = 1 << order;
2060
2061 __slab_clear_pfmemalloc(slab);
2062 folio->mapping = NULL;
2063 /* Make the mapping reset visible before clearing the flag */
2064 smp_wmb();
2065 __folio_clear_slab(folio);
2066 if (current->reclaim_state)
2067 current->reclaim_state->reclaimed_slab += pages;
2068 unaccount_slab(slab, order, s);
2069 __free_pages(folio_page(folio, 0), order);
2070}
2071
2072static void rcu_free_slab(struct rcu_head *h)
2073{
2074 struct slab *slab = container_of(h, struct slab, rcu_head);
2075
2076 __free_slab(slab->slab_cache, slab);
2077}
2078
2079static void free_slab(struct kmem_cache *s, struct slab *slab)
2080{
2081 if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
2082 void *p;
2083
2084 slab_pad_check(s, slab);
2085 for_each_object(p, s, slab_address(slab), slab->objects)
2086 check_object(s, slab, p, SLUB_RED_INACTIVE);
2087 }
2088
2089 if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU))
2090 call_rcu(&slab->rcu_head, rcu_free_slab);
2091 else
2092 __free_slab(s, slab);
2093}
2094
2095static void discard_slab(struct kmem_cache *s, struct slab *slab)
2096{
2097 dec_slabs_node(s, slab_nid(slab), slab->objects);
2098 free_slab(s, slab);
2099}
2100
2101/*
2102 * Management of partially allocated slabs.
2103 */
2104static inline void
2105__add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
2106{
2107 n->nr_partial++;
2108 if (tail == DEACTIVATE_TO_TAIL)
2109 list_add_tail(&slab->slab_list, &n->partial);
2110 else
2111 list_add(&slab->slab_list, &n->partial);
2112}
2113
2114static inline void add_partial(struct kmem_cache_node *n,
2115 struct slab *slab, int tail)
2116{
2117 lockdep_assert_held(&n->list_lock);
2118 __add_partial(n, slab, tail);
2119}
2120
2121static inline void remove_partial(struct kmem_cache_node *n,
2122 struct slab *slab)
2123{
2124 lockdep_assert_held(&n->list_lock);
2125 list_del(&slab->slab_list);
2126 n->nr_partial--;
2127}
2128
2129/*
2130 * Called only for kmem_cache_debug() caches instead of acquire_slab(), with a
2131 * slab from the n->partial list. Remove only a single object from the slab, do
2132 * the alloc_debug_processing() checks and leave the slab on the list, or move
2133 * it to full list if it was the last free object.
2134 */
2135static void *alloc_single_from_partial(struct kmem_cache *s,
2136 struct kmem_cache_node *n, struct slab *slab, int orig_size)
2137{
2138 void *object;
2139
2140 lockdep_assert_held(&n->list_lock);
2141
2142 object = slab->freelist;
2143 slab->freelist = get_freepointer(s, object);
2144 slab->inuse++;
2145
2146 if (!alloc_debug_processing(s, slab, object, orig_size)) {
2147 remove_partial(n, slab);
2148 return NULL;
2149 }
2150
2151 if (slab->inuse == slab->objects) {
2152 remove_partial(n, slab);
2153 add_full(s, n, slab);
2154 }
2155
2156 return object;
2157}
2158
2159/*
2160 * Called only for kmem_cache_debug() caches to allocate from a freshly
2161 * allocated slab. Allocate a single object instead of whole freelist
2162 * and put the slab to the partial (or full) list.
2163 */
2164static void *alloc_single_from_new_slab(struct kmem_cache *s,
2165 struct slab *slab, int orig_size)
2166{
2167 int nid = slab_nid(slab);
2168 struct kmem_cache_node *n = get_node(s, nid);
2169 unsigned long flags;
2170 void *object;
2171
2172
2173 object = slab->freelist;
2174 slab->freelist = get_freepointer(s, object);
2175 slab->inuse = 1;
2176
2177 if (!alloc_debug_processing(s, slab, object, orig_size))
2178 /*
2179 * It's not really expected that this would fail on a
2180 * freshly allocated slab, but a concurrent memory
2181 * corruption in theory could cause that.
2182 */
2183 return NULL;
2184
2185 spin_lock_irqsave(&n->list_lock, flags);
2186
2187 if (slab->inuse == slab->objects)
2188 add_full(s, n, slab);
2189 else
2190 add_partial(n, slab, DEACTIVATE_TO_HEAD);
2191
2192 inc_slabs_node(s, nid, slab->objects);
2193 spin_unlock_irqrestore(&n->list_lock, flags);
2194
2195 return object;
2196}
2197
2198/*
2199 * Remove slab from the partial list, freeze it and
2200 * return the pointer to the freelist.
2201 *
2202 * Returns a list of objects or NULL if it fails.
2203 */
2204static inline void *acquire_slab(struct kmem_cache *s,
2205 struct kmem_cache_node *n, struct slab *slab,
2206 int mode)
2207{
2208 void *freelist;
2209 unsigned long counters;
2210 struct slab new;
2211
2212 lockdep_assert_held(&n->list_lock);
2213
2214 /*
2215 * Zap the freelist and set the frozen bit.
2216 * The old freelist is the list of objects for the
2217 * per cpu allocation list.
2218 */
2219 freelist = slab->freelist;
2220 counters = slab->counters;
2221 new.counters = counters;
2222 if (mode) {
2223 new.inuse = slab->objects;
2224 new.freelist = NULL;
2225 } else {
2226 new.freelist = freelist;
2227 }
2228
2229 VM_BUG_ON(new.frozen);
2230 new.frozen = 1;
2231
2232 if (!__cmpxchg_double_slab(s, slab,
2233 freelist, counters,
2234 new.freelist, new.counters,
2235 "acquire_slab"))
2236 return NULL;
2237
2238 remove_partial(n, slab);
2239 WARN_ON(!freelist);
2240 return freelist;
2241}
2242
2243#ifdef CONFIG_SLUB_CPU_PARTIAL
2244static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
2245#else
2246static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
2247 int drain) { }
2248#endif
2249static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
2250
2251/*
2252 * Try to allocate a partial slab from a specific node.
2253 */
2254static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
2255 struct partial_context *pc)
2256{
2257 struct slab *slab, *slab2;
2258 void *object = NULL;
2259 unsigned long flags;
2260 unsigned int partial_slabs = 0;
2261
2262 /*
2263 * Racy check. If we mistakenly see no partial slabs then we
2264 * just allocate an empty slab. If we mistakenly try to get a
2265 * partial slab and there is none available then get_partial()
2266 * will return NULL.
2267 */
2268 if (!n || !n->nr_partial)
2269 return NULL;
2270
2271 spin_lock_irqsave(&n->list_lock, flags);
2272 list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
2273 void *t;
2274
2275 if (!pfmemalloc_match(slab, pc->flags))
2276 continue;
2277
2278 if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
2279 object = alloc_single_from_partial(s, n, slab,
2280 pc->orig_size);
2281 if (object)
2282 break;
2283 continue;
2284 }
2285
2286 t = acquire_slab(s, n, slab, object == NULL);
2287 if (!t)
2288 break;
2289
2290 if (!object) {
2291 *pc->slab = slab;
2292 stat(s, ALLOC_FROM_PARTIAL);
2293 object = t;
2294 } else {
2295 put_cpu_partial(s, slab, 0);
2296 stat(s, CPU_PARTIAL_NODE);
2297 partial_slabs++;
2298 }
2299#ifdef CONFIG_SLUB_CPU_PARTIAL
2300 if (!kmem_cache_has_cpu_partial(s)
2301 || partial_slabs > s->cpu_partial_slabs / 2)
2302 break;
2303#else
2304 break;
2305#endif
2306
2307 }
2308 spin_unlock_irqrestore(&n->list_lock, flags);
2309 return object;
2310}
2311
2312/*
2313 * Get a slab from somewhere. Search in increasing NUMA distances.
2314 */
2315static void *get_any_partial(struct kmem_cache *s, struct partial_context *pc)
2316{
2317#ifdef CONFIG_NUMA
2318 struct zonelist *zonelist;
2319 struct zoneref *z;
2320 struct zone *zone;
2321 enum zone_type highest_zoneidx = gfp_zone(pc->flags);
2322 void *object;
2323 unsigned int cpuset_mems_cookie;
2324
2325 /*
2326 * The defrag ratio allows a configuration of the tradeoffs between
2327 * inter node defragmentation and node local allocations. A lower
2328 * defrag_ratio increases the tendency to do local allocations
2329 * instead of attempting to obtain partial slabs from other nodes.
2330 *
2331 * If the defrag_ratio is set to 0 then kmalloc() always
2332 * returns node local objects. If the ratio is higher then kmalloc()
2333 * may return off node objects because partial slabs are obtained
2334 * from other nodes and filled up.
2335 *
2336 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2337 * (which makes defrag_ratio = 1000) then every (well almost)
2338 * allocation will first attempt to defrag slab caches on other nodes.
2339 * This means scanning over all nodes to look for partial slabs which
2340 * may be expensive if we do it every time we are trying to find a slab
2341 * with available objects.
2342 */
2343 if (!s->remote_node_defrag_ratio ||
2344 get_cycles() % 1024 > s->remote_node_defrag_ratio)
2345 return NULL;
2346
2347 do {
2348 cpuset_mems_cookie = read_mems_allowed_begin();
2349 zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
2350 for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
2351 struct kmem_cache_node *n;
2352
2353 n = get_node(s, zone_to_nid(zone));
2354
2355 if (n && cpuset_zone_allowed(zone, pc->flags) &&
2356 n->nr_partial > s->min_partial) {
2357 object = get_partial_node(s, n, pc);
2358 if (object) {
2359 /*
2360 * Don't check read_mems_allowed_retry()
2361 * here - if mems_allowed was updated in
2362 * parallel, that was a harmless race
2363 * between allocation and the cpuset
2364 * update
2365 */
2366 return object;
2367 }
2368 }
2369 }
2370 } while (read_mems_allowed_retry(cpuset_mems_cookie));
2371#endif /* CONFIG_NUMA */
2372 return NULL;
2373}
2374
2375/*
2376 * Get a partial slab, lock it and return it.
2377 */
2378static void *get_partial(struct kmem_cache *s, int node, struct partial_context *pc)
2379{
2380 void *object;
2381 int searchnode = node;
2382
2383 if (node == NUMA_NO_NODE)
2384 searchnode = numa_mem_id();
2385
2386 object = get_partial_node(s, get_node(s, searchnode), pc);
2387 if (object || node != NUMA_NO_NODE)
2388 return object;
2389
2390 return get_any_partial(s, pc);
2391}
2392
2393#ifndef CONFIG_SLUB_TINY
2394
2395#ifdef CONFIG_PREEMPTION
2396/*
2397 * Calculate the next globally unique transaction for disambiguation
2398 * during cmpxchg. The transactions start with the cpu number and are then
2399 * incremented by CONFIG_NR_CPUS.
2400 */
2401#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
2402#else
2403/*
2404 * No preemption supported therefore also no need to check for
2405 * different cpus.
2406 */
2407#define TID_STEP 1
2408#endif /* CONFIG_PREEMPTION */
2409
2410static inline unsigned long next_tid(unsigned long tid)
2411{
2412 return tid + TID_STEP;
2413}
2414
2415#ifdef SLUB_DEBUG_CMPXCHG
2416static inline unsigned int tid_to_cpu(unsigned long tid)
2417{
2418 return tid % TID_STEP;
2419}
2420
2421static inline unsigned long tid_to_event(unsigned long tid)
2422{
2423 return tid / TID_STEP;
2424}
2425#endif
2426
2427static inline unsigned int init_tid(int cpu)
2428{
2429 return cpu;
2430}
2431
2432static inline void note_cmpxchg_failure(const char *n,
2433 const struct kmem_cache *s, unsigned long tid)
2434{
2435#ifdef SLUB_DEBUG_CMPXCHG
2436 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2437
2438 pr_info("%s %s: cmpxchg redo ", n, s->name);
2439
2440#ifdef CONFIG_PREEMPTION
2441 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2442 pr_warn("due to cpu change %d -> %d\n",
2443 tid_to_cpu(tid), tid_to_cpu(actual_tid));
2444 else
2445#endif
2446 if (tid_to_event(tid) != tid_to_event(actual_tid))
2447 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2448 tid_to_event(tid), tid_to_event(actual_tid));
2449 else
2450 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2451 actual_tid, tid, next_tid(tid));
2452#endif
2453 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2454}
2455
2456static void init_kmem_cache_cpus(struct kmem_cache *s)
2457{
2458 int cpu;
2459 struct kmem_cache_cpu *c;
2460
2461 for_each_possible_cpu(cpu) {
2462 c = per_cpu_ptr(s->cpu_slab, cpu);
2463 local_lock_init(&c->lock);
2464 c->tid = init_tid(cpu);
2465 }
2466}
2467
2468/*
2469 * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
2470 * unfreezes the slabs and puts it on the proper list.
2471 * Assumes the slab has been already safely taken away from kmem_cache_cpu
2472 * by the caller.
2473 */
2474static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
2475 void *freelist)
2476{
2477 enum slab_modes { M_NONE, M_PARTIAL, M_FREE, M_FULL_NOLIST };
2478 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
2479 int free_delta = 0;
2480 enum slab_modes mode = M_NONE;
2481 void *nextfree, *freelist_iter, *freelist_tail;
2482 int tail = DEACTIVATE_TO_HEAD;
2483 unsigned long flags = 0;
2484 struct slab new;
2485 struct slab old;
2486
2487 if (slab->freelist) {
2488 stat(s, DEACTIVATE_REMOTE_FREES);
2489 tail = DEACTIVATE_TO_TAIL;
2490 }
2491
2492 /*
2493 * Stage one: Count the objects on cpu's freelist as free_delta and
2494 * remember the last object in freelist_tail for later splicing.
2495 */
2496 freelist_tail = NULL;
2497 freelist_iter = freelist;
2498 while (freelist_iter) {
2499 nextfree = get_freepointer(s, freelist_iter);
2500
2501 /*
2502 * If 'nextfree' is invalid, it is possible that the object at
2503 * 'freelist_iter' is already corrupted. So isolate all objects
2504 * starting at 'freelist_iter' by skipping them.
2505 */
2506 if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
2507 break;
2508
2509 freelist_tail = freelist_iter;
2510 free_delta++;
2511
2512 freelist_iter = nextfree;
2513 }
2514
2515 /*
2516 * Stage two: Unfreeze the slab while splicing the per-cpu
2517 * freelist to the head of slab's freelist.
2518 *
2519 * Ensure that the slab is unfrozen while the list presence
2520 * reflects the actual number of objects during unfreeze.
2521 *
2522 * We first perform cmpxchg holding lock and insert to list
2523 * when it succeed. If there is mismatch then the slab is not
2524 * unfrozen and number of objects in the slab may have changed.
2525 * Then release lock and retry cmpxchg again.
2526 */
2527redo:
2528
2529 old.freelist = READ_ONCE(slab->freelist);
2530 old.counters = READ_ONCE(slab->counters);
2531 VM_BUG_ON(!old.frozen);
2532
2533 /* Determine target state of the slab */
2534 new.counters = old.counters;
2535 if (freelist_tail) {
2536 new.inuse -= free_delta;
2537 set_freepointer(s, freelist_tail, old.freelist);
2538 new.freelist = freelist;
2539 } else
2540 new.freelist = old.freelist;
2541
2542 new.frozen = 0;
2543
2544 if (!new.inuse && n->nr_partial >= s->min_partial) {
2545 mode = M_FREE;
2546 } else if (new.freelist) {
2547 mode = M_PARTIAL;
2548 /*
2549 * Taking the spinlock removes the possibility that
2550 * acquire_slab() will see a slab that is frozen
2551 */
2552 spin_lock_irqsave(&n->list_lock, flags);
2553 } else {
2554 mode = M_FULL_NOLIST;
2555 }
2556
2557
2558 if (!cmpxchg_double_slab(s, slab,
2559 old.freelist, old.counters,
2560 new.freelist, new.counters,
2561 "unfreezing slab")) {
2562 if (mode == M_PARTIAL)
2563 spin_unlock_irqrestore(&n->list_lock, flags);
2564 goto redo;
2565 }
2566
2567
2568 if (mode == M_PARTIAL) {
2569 add_partial(n, slab, tail);
2570 spin_unlock_irqrestore(&n->list_lock, flags);
2571 stat(s, tail);
2572 } else if (mode == M_FREE) {
2573 stat(s, DEACTIVATE_EMPTY);
2574 discard_slab(s, slab);
2575 stat(s, FREE_SLAB);
2576 } else if (mode == M_FULL_NOLIST) {
2577 stat(s, DEACTIVATE_FULL);
2578 }
2579}
2580
2581#ifdef CONFIG_SLUB_CPU_PARTIAL
2582static void __unfreeze_partials(struct kmem_cache *s, struct slab *partial_slab)
2583{
2584 struct kmem_cache_node *n = NULL, *n2 = NULL;
2585 struct slab *slab, *slab_to_discard = NULL;
2586 unsigned long flags = 0;
2587
2588 while (partial_slab) {
2589 struct slab new;
2590 struct slab old;
2591
2592 slab = partial_slab;
2593 partial_slab = slab->next;
2594
2595 n2 = get_node(s, slab_nid(slab));
2596 if (n != n2) {
2597 if (n)
2598 spin_unlock_irqrestore(&n->list_lock, flags);
2599
2600 n = n2;
2601 spin_lock_irqsave(&n->list_lock, flags);
2602 }
2603
2604 do {
2605
2606 old.freelist = slab->freelist;
2607 old.counters = slab->counters;
2608 VM_BUG_ON(!old.frozen);
2609
2610 new.counters = old.counters;
2611 new.freelist = old.freelist;
2612
2613 new.frozen = 0;
2614
2615 } while (!__cmpxchg_double_slab(s, slab,
2616 old.freelist, old.counters,
2617 new.freelist, new.counters,
2618 "unfreezing slab"));
2619
2620 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2621 slab->next = slab_to_discard;
2622 slab_to_discard = slab;
2623 } else {
2624 add_partial(n, slab, DEACTIVATE_TO_TAIL);
2625 stat(s, FREE_ADD_PARTIAL);
2626 }
2627 }
2628
2629 if (n)
2630 spin_unlock_irqrestore(&n->list_lock, flags);
2631
2632 while (slab_to_discard) {
2633 slab = slab_to_discard;
2634 slab_to_discard = slab_to_discard->next;
2635
2636 stat(s, DEACTIVATE_EMPTY);
2637 discard_slab(s, slab);
2638 stat(s, FREE_SLAB);
2639 }
2640}
2641
2642/*
2643 * Unfreeze all the cpu partial slabs.
2644 */
2645static void unfreeze_partials(struct kmem_cache *s)
2646{
2647 struct slab *partial_slab;
2648 unsigned long flags;
2649
2650 local_lock_irqsave(&s->cpu_slab->lock, flags);
2651 partial_slab = this_cpu_read(s->cpu_slab->partial);
2652 this_cpu_write(s->cpu_slab->partial, NULL);
2653 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2654
2655 if (partial_slab)
2656 __unfreeze_partials(s, partial_slab);
2657}
2658
2659static void unfreeze_partials_cpu(struct kmem_cache *s,
2660 struct kmem_cache_cpu *c)
2661{
2662 struct slab *partial_slab;
2663
2664 partial_slab = slub_percpu_partial(c);
2665 c->partial = NULL;
2666
2667 if (partial_slab)
2668 __unfreeze_partials(s, partial_slab);
2669}
2670
2671/*
2672 * Put a slab that was just frozen (in __slab_free|get_partial_node) into a
2673 * partial slab slot if available.
2674 *
2675 * If we did not find a slot then simply move all the partials to the
2676 * per node partial list.
2677 */
2678static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
2679{
2680 struct slab *oldslab;
2681 struct slab *slab_to_unfreeze = NULL;
2682 unsigned long flags;
2683 int slabs = 0;
2684
2685 local_lock_irqsave(&s->cpu_slab->lock, flags);
2686
2687 oldslab = this_cpu_read(s->cpu_slab->partial);
2688
2689 if (oldslab) {
2690 if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
2691 /*
2692 * Partial array is full. Move the existing set to the
2693 * per node partial list. Postpone the actual unfreezing
2694 * outside of the critical section.
2695 */
2696 slab_to_unfreeze = oldslab;
2697 oldslab = NULL;
2698 } else {
2699 slabs = oldslab->slabs;
2700 }
2701 }
2702
2703 slabs++;
2704
2705 slab->slabs = slabs;
2706 slab->next = oldslab;
2707
2708 this_cpu_write(s->cpu_slab->partial, slab);
2709
2710 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2711
2712 if (slab_to_unfreeze) {
2713 __unfreeze_partials(s, slab_to_unfreeze);
2714 stat(s, CPU_PARTIAL_DRAIN);
2715 }
2716}
2717
2718#else /* CONFIG_SLUB_CPU_PARTIAL */
2719
2720static inline void unfreeze_partials(struct kmem_cache *s) { }
2721static inline void unfreeze_partials_cpu(struct kmem_cache *s,
2722 struct kmem_cache_cpu *c) { }
2723
2724#endif /* CONFIG_SLUB_CPU_PARTIAL */
2725
2726static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2727{
2728 unsigned long flags;
2729 struct slab *slab;
2730 void *freelist;
2731
2732 local_lock_irqsave(&s->cpu_slab->lock, flags);
2733
2734 slab = c->slab;
2735 freelist = c->freelist;
2736
2737 c->slab = NULL;
2738 c->freelist = NULL;
2739 c->tid = next_tid(c->tid);
2740
2741 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2742
2743 if (slab) {
2744 deactivate_slab(s, slab, freelist);
2745 stat(s, CPUSLAB_FLUSH);
2746 }
2747}
2748
2749static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2750{
2751 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2752 void *freelist = c->freelist;
2753 struct slab *slab = c->slab;
2754
2755 c->slab = NULL;
2756 c->freelist = NULL;
2757 c->tid = next_tid(c->tid);
2758
2759 if (slab) {
2760 deactivate_slab(s, slab, freelist);
2761 stat(s, CPUSLAB_FLUSH);
2762 }
2763
2764 unfreeze_partials_cpu(s, c);
2765}
2766
2767struct slub_flush_work {
2768 struct work_struct work;
2769 struct kmem_cache *s;
2770 bool skip;
2771};
2772
2773/*
2774 * Flush cpu slab.
2775 *
2776 * Called from CPU work handler with migration disabled.
2777 */
2778static void flush_cpu_slab(struct work_struct *w)
2779{
2780 struct kmem_cache *s;
2781 struct kmem_cache_cpu *c;
2782 struct slub_flush_work *sfw;
2783
2784 sfw = container_of(w, struct slub_flush_work, work);
2785
2786 s = sfw->s;
2787 c = this_cpu_ptr(s->cpu_slab);
2788
2789 if (c->slab)
2790 flush_slab(s, c);
2791
2792 unfreeze_partials(s);
2793}
2794
2795static bool has_cpu_slab(int cpu, struct kmem_cache *s)
2796{
2797 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2798
2799 return c->slab || slub_percpu_partial(c);
2800}
2801
2802static DEFINE_MUTEX(flush_lock);
2803static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
2804
2805static void flush_all_cpus_locked(struct kmem_cache *s)
2806{
2807 struct slub_flush_work *sfw;
2808 unsigned int cpu;
2809
2810 lockdep_assert_cpus_held();
2811 mutex_lock(&flush_lock);
2812
2813 for_each_online_cpu(cpu) {
2814 sfw = &per_cpu(slub_flush, cpu);
2815 if (!has_cpu_slab(cpu, s)) {
2816 sfw->skip = true;
2817 continue;
2818 }
2819 INIT_WORK(&sfw->work, flush_cpu_slab);
2820 sfw->skip = false;
2821 sfw->s = s;
2822 queue_work_on(cpu, flushwq, &sfw->work);
2823 }
2824
2825 for_each_online_cpu(cpu) {
2826 sfw = &per_cpu(slub_flush, cpu);
2827 if (sfw->skip)
2828 continue;
2829 flush_work(&sfw->work);
2830 }
2831
2832 mutex_unlock(&flush_lock);
2833}
2834
2835static void flush_all(struct kmem_cache *s)
2836{
2837 cpus_read_lock();
2838 flush_all_cpus_locked(s);
2839 cpus_read_unlock();
2840}
2841
2842/*
2843 * Use the cpu notifier to insure that the cpu slabs are flushed when
2844 * necessary.
2845 */
2846static int slub_cpu_dead(unsigned int cpu)
2847{
2848 struct kmem_cache *s;
2849
2850 mutex_lock(&slab_mutex);
2851 list_for_each_entry(s, &slab_caches, list)
2852 __flush_cpu_slab(s, cpu);
2853 mutex_unlock(&slab_mutex);
2854 return 0;
2855}
2856
2857#else /* CONFIG_SLUB_TINY */
2858static inline void flush_all_cpus_locked(struct kmem_cache *s) { }
2859static inline void flush_all(struct kmem_cache *s) { }
2860static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { }
2861static inline int slub_cpu_dead(unsigned int cpu) { return 0; }
2862#endif /* CONFIG_SLUB_TINY */
2863
2864/*
2865 * Check if the objects in a per cpu structure fit numa
2866 * locality expectations.
2867 */
2868static inline int node_match(struct slab *slab, int node)
2869{
2870#ifdef CONFIG_NUMA
2871 if (node != NUMA_NO_NODE && slab_nid(slab) != node)
2872 return 0;
2873#endif
2874 return 1;
2875}
2876
2877#ifdef CONFIG_SLUB_DEBUG
2878static int count_free(struct slab *slab)
2879{
2880 return slab->objects - slab->inuse;
2881}
2882
2883static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2884{
2885 return atomic_long_read(&n->total_objects);
2886}
2887
2888/* Supports checking bulk free of a constructed freelist */
2889static inline bool free_debug_processing(struct kmem_cache *s,
2890 struct slab *slab, void *head, void *tail, int *bulk_cnt,
2891 unsigned long addr, depot_stack_handle_t handle)
2892{
2893 bool checks_ok = false;
2894 void *object = head;
2895 int cnt = 0;
2896
2897 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
2898 if (!check_slab(s, slab))
2899 goto out;
2900 }
2901
2902 if (slab->inuse < *bulk_cnt) {
2903 slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n",
2904 slab->inuse, *bulk_cnt);
2905 goto out;
2906 }
2907
2908next_object:
2909
2910 if (++cnt > *bulk_cnt)
2911 goto out_cnt;
2912
2913 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
2914 if (!free_consistency_checks(s, slab, object, addr))
2915 goto out;
2916 }
2917
2918 if (s->flags & SLAB_STORE_USER)
2919 set_track_update(s, object, TRACK_FREE, addr, handle);
2920 trace(s, slab, object, 0);
2921 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
2922 init_object(s, object, SLUB_RED_INACTIVE);
2923
2924 /* Reached end of constructed freelist yet? */
2925 if (object != tail) {
2926 object = get_freepointer(s, object);
2927 goto next_object;
2928 }
2929 checks_ok = true;
2930
2931out_cnt:
2932 if (cnt != *bulk_cnt) {
2933 slab_err(s, slab, "Bulk free expected %d objects but found %d\n",
2934 *bulk_cnt, cnt);
2935 *bulk_cnt = cnt;
2936 }
2937
2938out:
2939
2940 if (!checks_ok)
2941 slab_fix(s, "Object at 0x%p not freed", object);
2942
2943 return checks_ok;
2944}
2945#endif /* CONFIG_SLUB_DEBUG */
2946
2947#if defined(CONFIG_SLUB_DEBUG) || defined(SLAB_SUPPORTS_SYSFS)
2948static unsigned long count_partial(struct kmem_cache_node *n,
2949 int (*get_count)(struct slab *))
2950{
2951 unsigned long flags;
2952 unsigned long x = 0;
2953 struct slab *slab;
2954
2955 spin_lock_irqsave(&n->list_lock, flags);
2956 list_for_each_entry(slab, &n->partial, slab_list)
2957 x += get_count(slab);
2958 spin_unlock_irqrestore(&n->list_lock, flags);
2959 return x;
2960}
2961#endif /* CONFIG_SLUB_DEBUG || SLAB_SUPPORTS_SYSFS */
2962
2963#ifdef CONFIG_SLUB_DEBUG
2964static noinline void
2965slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2966{
2967 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2968 DEFAULT_RATELIMIT_BURST);
2969 int node;
2970 struct kmem_cache_node *n;
2971
2972 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2973 return;
2974
2975 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2976 nid, gfpflags, &gfpflags);
2977 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2978 s->name, s->object_size, s->size, oo_order(s->oo),
2979 oo_order(s->min));
2980
2981 if (oo_order(s->min) > get_order(s->object_size))
2982 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2983 s->name);
2984
2985 for_each_kmem_cache_node(s, node, n) {
2986 unsigned long nr_slabs;
2987 unsigned long nr_objs;
2988 unsigned long nr_free;
2989
2990 nr_free = count_partial(n, count_free);
2991 nr_slabs = node_nr_slabs(n);
2992 nr_objs = node_nr_objs(n);
2993
2994 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2995 node, nr_slabs, nr_objs, nr_free);
2996 }
2997}
2998#else /* CONFIG_SLUB_DEBUG */
2999static inline void
3000slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) { }
3001#endif
3002
3003static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
3004{
3005 if (unlikely(slab_test_pfmemalloc(slab)))
3006 return gfp_pfmemalloc_allowed(gfpflags);
3007
3008 return true;
3009}
3010
3011#ifndef CONFIG_SLUB_TINY
3012/*
3013 * Check the slab->freelist and either transfer the freelist to the
3014 * per cpu freelist or deactivate the slab.
3015 *
3016 * The slab is still frozen if the return value is not NULL.
3017 *
3018 * If this function returns NULL then the slab has been unfrozen.
3019 */
3020static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
3021{
3022 struct slab new;
3023 unsigned long counters;
3024 void *freelist;
3025
3026 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3027
3028 do {
3029 freelist = slab->freelist;
3030 counters = slab->counters;
3031
3032 new.counters = counters;
3033 VM_BUG_ON(!new.frozen);
3034
3035 new.inuse = slab->objects;
3036 new.frozen = freelist != NULL;
3037
3038 } while (!__cmpxchg_double_slab(s, slab,
3039 freelist, counters,
3040 NULL, new.counters,
3041 "get_freelist"));
3042
3043 return freelist;
3044}
3045
3046/*
3047 * Slow path. The lockless freelist is empty or we need to perform
3048 * debugging duties.
3049 *
3050 * Processing is still very fast if new objects have been freed to the
3051 * regular freelist. In that case we simply take over the regular freelist
3052 * as the lockless freelist and zap the regular freelist.
3053 *
3054 * If that is not working then we fall back to the partial lists. We take the
3055 * first element of the freelist as the object to allocate now and move the
3056 * rest of the freelist to the lockless freelist.
3057 *
3058 * And if we were unable to get a new slab from the partial slab lists then
3059 * we need to allocate a new slab. This is the slowest path since it involves
3060 * a call to the page allocator and the setup of a new slab.
3061 *
3062 * Version of __slab_alloc to use when we know that preemption is
3063 * already disabled (which is the case for bulk allocation).
3064 */
3065static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3066 unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3067{
3068 void *freelist;
3069 struct slab *slab;
3070 unsigned long flags;
3071 struct partial_context pc;
3072
3073 stat(s, ALLOC_SLOWPATH);
3074
3075reread_slab:
3076
3077 slab = READ_ONCE(c->slab);
3078 if (!slab) {
3079 /*
3080 * if the node is not online or has no normal memory, just
3081 * ignore the node constraint
3082 */
3083 if (unlikely(node != NUMA_NO_NODE &&
3084 !node_isset(node, slab_nodes)))
3085 node = NUMA_NO_NODE;
3086 goto new_slab;
3087 }
3088redo:
3089
3090 if (unlikely(!node_match(slab, node))) {
3091 /*
3092 * same as above but node_match() being false already
3093 * implies node != NUMA_NO_NODE
3094 */
3095 if (!node_isset(node, slab_nodes)) {
3096 node = NUMA_NO_NODE;
3097 } else {
3098 stat(s, ALLOC_NODE_MISMATCH);
3099 goto deactivate_slab;
3100 }
3101 }
3102
3103 /*
3104 * By rights, we should be searching for a slab page that was
3105 * PFMEMALLOC but right now, we are losing the pfmemalloc
3106 * information when the page leaves the per-cpu allocator
3107 */
3108 if (unlikely(!pfmemalloc_match(slab, gfpflags)))
3109 goto deactivate_slab;
3110
3111 /* must check again c->slab in case we got preempted and it changed */
3112 local_lock_irqsave(&s->cpu_slab->lock, flags);
3113 if (unlikely(slab != c->slab)) {
3114 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3115 goto reread_slab;
3116 }
3117 freelist = c->freelist;
3118 if (freelist)
3119 goto load_freelist;
3120
3121 freelist = get_freelist(s, slab);
3122
3123 if (!freelist) {
3124 c->slab = NULL;
3125 c->tid = next_tid(c->tid);
3126 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3127 stat(s, DEACTIVATE_BYPASS);
3128 goto new_slab;
3129 }
3130
3131 stat(s, ALLOC_REFILL);
3132
3133load_freelist:
3134
3135 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3136
3137 /*
3138 * freelist is pointing to the list of objects to be used.
3139 * slab is pointing to the slab from which the objects are obtained.
3140 * That slab must be frozen for per cpu allocations to work.
3141 */
3142 VM_BUG_ON(!c->slab->frozen);
3143 c->freelist = get_freepointer(s, freelist);
3144 c->tid = next_tid(c->tid);
3145 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3146 return freelist;
3147
3148deactivate_slab:
3149
3150 local_lock_irqsave(&s->cpu_slab->lock, flags);
3151 if (slab != c->slab) {
3152 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3153 goto reread_slab;
3154 }
3155 freelist = c->freelist;
3156 c->slab = NULL;
3157 c->freelist = NULL;
3158 c->tid = next_tid(c->tid);
3159 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3160 deactivate_slab(s, slab, freelist);
3161
3162new_slab:
3163
3164 if (slub_percpu_partial(c)) {
3165 local_lock_irqsave(&s->cpu_slab->lock, flags);
3166 if (unlikely(c->slab)) {
3167 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3168 goto reread_slab;
3169 }
3170 if (unlikely(!slub_percpu_partial(c))) {
3171 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3172 /* we were preempted and partial list got empty */
3173 goto new_objects;
3174 }
3175
3176 slab = c->slab = slub_percpu_partial(c);
3177 slub_set_percpu_partial(c, slab);
3178 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3179 stat(s, CPU_PARTIAL_ALLOC);
3180 goto redo;
3181 }
3182
3183new_objects:
3184
3185 pc.flags = gfpflags;
3186 pc.slab = &slab;
3187 pc.orig_size = orig_size;
3188 freelist = get_partial(s, node, &pc);
3189 if (freelist)
3190 goto check_new_slab;
3191
3192 slub_put_cpu_ptr(s->cpu_slab);
3193 slab = new_slab(s, gfpflags, node);
3194 c = slub_get_cpu_ptr(s->cpu_slab);
3195
3196 if (unlikely(!slab)) {
3197 slab_out_of_memory(s, gfpflags, node);
3198 return NULL;
3199 }
3200
3201 stat(s, ALLOC_SLAB);
3202
3203 if (kmem_cache_debug(s)) {
3204 freelist = alloc_single_from_new_slab(s, slab, orig_size);
3205
3206 if (unlikely(!freelist))
3207 goto new_objects;
3208
3209 if (s->flags & SLAB_STORE_USER)
3210 set_track(s, freelist, TRACK_ALLOC, addr);
3211
3212 return freelist;
3213 }
3214
3215 /*
3216 * No other reference to the slab yet so we can
3217 * muck around with it freely without cmpxchg
3218 */
3219 freelist = slab->freelist;
3220 slab->freelist = NULL;
3221 slab->inuse = slab->objects;
3222 slab->frozen = 1;
3223
3224 inc_slabs_node(s, slab_nid(slab), slab->objects);
3225
3226check_new_slab:
3227
3228 if (kmem_cache_debug(s)) {
3229 /*
3230 * For debug caches here we had to go through
3231 * alloc_single_from_partial() so just store the tracking info
3232 * and return the object
3233 */
3234 if (s->flags & SLAB_STORE_USER)
3235 set_track(s, freelist, TRACK_ALLOC, addr);
3236
3237 return freelist;
3238 }
3239
3240 if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
3241 /*
3242 * For !pfmemalloc_match() case we don't load freelist so that
3243 * we don't make further mismatched allocations easier.
3244 */
3245 deactivate_slab(s, slab, get_freepointer(s, freelist));
3246 return freelist;
3247 }
3248
3249retry_load_slab:
3250
3251 local_lock_irqsave(&s->cpu_slab->lock, flags);
3252 if (unlikely(c->slab)) {
3253 void *flush_freelist = c->freelist;
3254 struct slab *flush_slab = c->slab;
3255
3256 c->slab = NULL;
3257 c->freelist = NULL;
3258 c->tid = next_tid(c->tid);
3259
3260 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3261
3262 deactivate_slab(s, flush_slab, flush_freelist);
3263
3264 stat(s, CPUSLAB_FLUSH);
3265
3266 goto retry_load_slab;
3267 }
3268 c->slab = slab;
3269
3270 goto load_freelist;
3271}
3272
3273/*
3274 * A wrapper for ___slab_alloc() for contexts where preemption is not yet
3275 * disabled. Compensates for possible cpu changes by refetching the per cpu area
3276 * pointer.
3277 */
3278static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3279 unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3280{
3281 void *p;
3282
3283#ifdef CONFIG_PREEMPT_COUNT
3284 /*
3285 * We may have been preempted and rescheduled on a different
3286 * cpu before disabling preemption. Need to reload cpu area
3287 * pointer.
3288 */
3289 c = slub_get_cpu_ptr(s->cpu_slab);
3290#endif
3291
3292 p = ___slab_alloc(s, gfpflags, node, addr, c, orig_size);
3293#ifdef CONFIG_PREEMPT_COUNT
3294 slub_put_cpu_ptr(s->cpu_slab);
3295#endif
3296 return p;
3297}
3298
3299static __always_inline void *__slab_alloc_node(struct kmem_cache *s,
3300 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3301{
3302 struct kmem_cache_cpu *c;
3303 struct slab *slab;
3304 unsigned long tid;
3305 void *object;
3306
3307redo:
3308 /*
3309 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
3310 * enabled. We may switch back and forth between cpus while
3311 * reading from one cpu area. That does not matter as long
3312 * as we end up on the original cpu again when doing the cmpxchg.
3313 *
3314 * We must guarantee that tid and kmem_cache_cpu are retrieved on the
3315 * same cpu. We read first the kmem_cache_cpu pointer and use it to read
3316 * the tid. If we are preempted and switched to another cpu between the
3317 * two reads, it's OK as the two are still associated with the same cpu
3318 * and cmpxchg later will validate the cpu.
3319 */
3320 c = raw_cpu_ptr(s->cpu_slab);
3321 tid = READ_ONCE(c->tid);
3322
3323 /*
3324 * Irqless object alloc/free algorithm used here depends on sequence
3325 * of fetching cpu_slab's data. tid should be fetched before anything
3326 * on c to guarantee that object and slab associated with previous tid
3327 * won't be used with current tid. If we fetch tid first, object and
3328 * slab could be one associated with next tid and our alloc/free
3329 * request will be failed. In this case, we will retry. So, no problem.
3330 */
3331 barrier();
3332
3333 /*
3334 * The transaction ids are globally unique per cpu and per operation on
3335 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
3336 * occurs on the right processor and that there was no operation on the
3337 * linked list in between.
3338 */
3339
3340 object = c->freelist;
3341 slab = c->slab;
3342
3343 if (!USE_LOCKLESS_FAST_PATH() ||
3344 unlikely(!object || !slab || !node_match(slab, node))) {
3345 object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
3346 } else {
3347 void *next_object = get_freepointer_safe(s, object);
3348
3349 /*
3350 * The cmpxchg will only match if there was no additional
3351 * operation and if we are on the right processor.
3352 *
3353 * The cmpxchg does the following atomically (without lock
3354 * semantics!)
3355 * 1. Relocate first pointer to the current per cpu area.
3356 * 2. Verify that tid and freelist have not been changed
3357 * 3. If they were not changed replace tid and freelist
3358 *
3359 * Since this is without lock semantics the protection is only
3360 * against code executing on this cpu *not* from access by
3361 * other cpus.
3362 */
3363 if (unlikely(!this_cpu_cmpxchg_double(
3364 s->cpu_slab->freelist, s->cpu_slab->tid,
3365 object, tid,
3366 next_object, next_tid(tid)))) {
3367
3368 note_cmpxchg_failure("slab_alloc", s, tid);
3369 goto redo;
3370 }
3371 prefetch_freepointer(s, next_object);
3372 stat(s, ALLOC_FASTPATH);
3373 }
3374
3375 return object;
3376}
3377#else /* CONFIG_SLUB_TINY */
3378static void *__slab_alloc_node(struct kmem_cache *s,
3379 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3380{
3381 struct partial_context pc;
3382 struct slab *slab;
3383 void *object;
3384
3385 pc.flags = gfpflags;
3386 pc.slab = &slab;
3387 pc.orig_size = orig_size;
3388 object = get_partial(s, node, &pc);
3389
3390 if (object)
3391 return object;
3392
3393 slab = new_slab(s, gfpflags, node);
3394 if (unlikely(!slab)) {
3395 slab_out_of_memory(s, gfpflags, node);
3396 return NULL;
3397 }
3398
3399 object = alloc_single_from_new_slab(s, slab, orig_size);
3400
3401 return object;
3402}
3403#endif /* CONFIG_SLUB_TINY */
3404
3405/*
3406 * If the object has been wiped upon free, make sure it's fully initialized by
3407 * zeroing out freelist pointer.
3408 */
3409static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
3410 void *obj)
3411{
3412 if (unlikely(slab_want_init_on_free(s)) && obj)
3413 memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
3414 0, sizeof(void *));
3415}
3416
3417/*
3418 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
3419 * have the fastpath folded into their functions. So no function call
3420 * overhead for requests that can be satisfied on the fastpath.
3421 *
3422 * The fastpath works by first checking if the lockless freelist can be used.
3423 * If not then __slab_alloc is called for slow processing.
3424 *
3425 * Otherwise we can simply pick the next object from the lockless free list.
3426 */
3427static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
3428 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3429{
3430 void *object;
3431 struct obj_cgroup *objcg = NULL;
3432 bool init = false;
3433
3434 s = slab_pre_alloc_hook(s, lru, &objcg, 1, gfpflags);
3435 if (!s)
3436 return NULL;
3437
3438 object = kfence_alloc(s, orig_size, gfpflags);
3439 if (unlikely(object))
3440 goto out;
3441
3442 object = __slab_alloc_node(s, gfpflags, node, addr, orig_size);
3443
3444 maybe_wipe_obj_freeptr(s, object);
3445 init = slab_want_init_on_alloc(gfpflags, s);
3446
3447out:
3448 /*
3449 * When init equals 'true', like for kzalloc() family, only
3450 * @orig_size bytes might be zeroed instead of s->object_size
3451 */
3452 slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init, orig_size);
3453
3454 return object;
3455}
3456
3457static __fastpath_inline void *slab_alloc(struct kmem_cache *s, struct list_lru *lru,
3458 gfp_t gfpflags, unsigned long addr, size_t orig_size)
3459{
3460 return slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, addr, orig_size);
3461}
3462
3463static __fastpath_inline
3464void *__kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
3465 gfp_t gfpflags)
3466{
3467 void *ret = slab_alloc(s, lru, gfpflags, _RET_IP_, s->object_size);
3468
3469 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
3470
3471 return ret;
3472}
3473
3474void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
3475{
3476 return __kmem_cache_alloc_lru(s, NULL, gfpflags);
3477}
3478EXPORT_SYMBOL(kmem_cache_alloc);
3479
3480void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
3481 gfp_t gfpflags)
3482{
3483 return __kmem_cache_alloc_lru(s, lru, gfpflags);
3484}
3485EXPORT_SYMBOL(kmem_cache_alloc_lru);
3486
3487void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
3488 int node, size_t orig_size,
3489 unsigned long caller)
3490{
3491 return slab_alloc_node(s, NULL, gfpflags, node,
3492 caller, orig_size);
3493}
3494
3495void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
3496{
3497 void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
3498
3499 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
3500
3501 return ret;
3502}
3503EXPORT_SYMBOL(kmem_cache_alloc_node);
3504
3505static noinline void free_to_partial_list(
3506 struct kmem_cache *s, struct slab *slab,
3507 void *head, void *tail, int bulk_cnt,
3508 unsigned long addr)
3509{
3510 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
3511 struct slab *slab_free = NULL;
3512 int cnt = bulk_cnt;
3513 unsigned long flags;
3514 depot_stack_handle_t handle = 0;
3515
3516 if (s->flags & SLAB_STORE_USER)
3517 handle = set_track_prepare();
3518
3519 spin_lock_irqsave(&n->list_lock, flags);
3520
3521 if (free_debug_processing(s, slab, head, tail, &cnt, addr, handle)) {
3522 void *prior = slab->freelist;
3523
3524 /* Perform the actual freeing while we still hold the locks */
3525 slab->inuse -= cnt;
3526 set_freepointer(s, tail, prior);
3527 slab->freelist = head;
3528
3529 /*
3530 * If the slab is empty, and node's partial list is full,
3531 * it should be discarded anyway no matter it's on full or
3532 * partial list.
3533 */
3534 if (slab->inuse == 0 && n->nr_partial >= s->min_partial)
3535 slab_free = slab;
3536
3537 if (!prior) {
3538 /* was on full list */
3539 remove_full(s, n, slab);
3540 if (!slab_free) {
3541 add_partial(n, slab, DEACTIVATE_TO_TAIL);
3542 stat(s, FREE_ADD_PARTIAL);
3543 }
3544 } else if (slab_free) {
3545 remove_partial(n, slab);
3546 stat(s, FREE_REMOVE_PARTIAL);
3547 }
3548 }
3549
3550 if (slab_free) {
3551 /*
3552 * Update the counters while still holding n->list_lock to
3553 * prevent spurious validation warnings
3554 */
3555 dec_slabs_node(s, slab_nid(slab_free), slab_free->objects);
3556 }
3557
3558 spin_unlock_irqrestore(&n->list_lock, flags);
3559
3560 if (slab_free) {
3561 stat(s, FREE_SLAB);
3562 free_slab(s, slab_free);
3563 }
3564}
3565
3566/*
3567 * Slow path handling. This may still be called frequently since objects
3568 * have a longer lifetime than the cpu slabs in most processing loads.
3569 *
3570 * So we still attempt to reduce cache line usage. Just take the slab
3571 * lock and free the item. If there is no additional partial slab
3572 * handling required then we can return immediately.
3573 */
3574static void __slab_free(struct kmem_cache *s, struct slab *slab,
3575 void *head, void *tail, int cnt,
3576 unsigned long addr)
3577
3578{
3579 void *prior;
3580 int was_frozen;
3581 struct slab new;
3582 unsigned long counters;
3583 struct kmem_cache_node *n = NULL;
3584 unsigned long flags;
3585
3586 stat(s, FREE_SLOWPATH);
3587
3588 if (kfence_free(head))
3589 return;
3590
3591 if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
3592 free_to_partial_list(s, slab, head, tail, cnt, addr);
3593 return;
3594 }
3595
3596 do {
3597 if (unlikely(n)) {
3598 spin_unlock_irqrestore(&n->list_lock, flags);
3599 n = NULL;
3600 }
3601 prior = slab->freelist;
3602 counters = slab->counters;
3603 set_freepointer(s, tail, prior);
3604 new.counters = counters;
3605 was_frozen = new.frozen;
3606 new.inuse -= cnt;
3607 if ((!new.inuse || !prior) && !was_frozen) {
3608
3609 if (kmem_cache_has_cpu_partial(s) && !prior) {
3610
3611 /*
3612 * Slab was on no list before and will be
3613 * partially empty
3614 * We can defer the list move and instead
3615 * freeze it.
3616 */
3617 new.frozen = 1;
3618
3619 } else { /* Needs to be taken off a list */
3620
3621 n = get_node(s, slab_nid(slab));
3622 /*
3623 * Speculatively acquire the list_lock.
3624 * If the cmpxchg does not succeed then we may
3625 * drop the list_lock without any processing.
3626 *
3627 * Otherwise the list_lock will synchronize with
3628 * other processors updating the list of slabs.
3629 */
3630 spin_lock_irqsave(&n->list_lock, flags);
3631
3632 }
3633 }
3634
3635 } while (!cmpxchg_double_slab(s, slab,
3636 prior, counters,
3637 head, new.counters,
3638 "__slab_free"));
3639
3640 if (likely(!n)) {
3641
3642 if (likely(was_frozen)) {
3643 /*
3644 * The list lock was not taken therefore no list
3645 * activity can be necessary.
3646 */
3647 stat(s, FREE_FROZEN);
3648 } else if (new.frozen) {
3649 /*
3650 * If we just froze the slab then put it onto the
3651 * per cpu partial list.
3652 */
3653 put_cpu_partial(s, slab, 1);
3654 stat(s, CPU_PARTIAL_FREE);
3655 }
3656
3657 return;
3658 }
3659
3660 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
3661 goto slab_empty;
3662
3663 /*
3664 * Objects left in the slab. If it was not on the partial list before
3665 * then add it.
3666 */
3667 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
3668 remove_full(s, n, slab);
3669 add_partial(n, slab, DEACTIVATE_TO_TAIL);
3670 stat(s, FREE_ADD_PARTIAL);
3671 }
3672 spin_unlock_irqrestore(&n->list_lock, flags);
3673 return;
3674
3675slab_empty:
3676 if (prior) {
3677 /*
3678 * Slab on the partial list.
3679 */
3680 remove_partial(n, slab);
3681 stat(s, FREE_REMOVE_PARTIAL);
3682 } else {
3683 /* Slab must be on the full list */
3684 remove_full(s, n, slab);
3685 }
3686
3687 spin_unlock_irqrestore(&n->list_lock, flags);
3688 stat(s, FREE_SLAB);
3689 discard_slab(s, slab);
3690}
3691
3692#ifndef CONFIG_SLUB_TINY
3693/*
3694 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
3695 * can perform fastpath freeing without additional function calls.
3696 *
3697 * The fastpath is only possible if we are freeing to the current cpu slab
3698 * of this processor. This typically the case if we have just allocated
3699 * the item before.
3700 *
3701 * If fastpath is not possible then fall back to __slab_free where we deal
3702 * with all sorts of special processing.
3703 *
3704 * Bulk free of a freelist with several objects (all pointing to the
3705 * same slab) possible by specifying head and tail ptr, plus objects
3706 * count (cnt). Bulk free indicated by tail pointer being set.
3707 */
3708static __always_inline void do_slab_free(struct kmem_cache *s,
3709 struct slab *slab, void *head, void *tail,
3710 int cnt, unsigned long addr)
3711{
3712 void *tail_obj = tail ? : head;
3713 struct kmem_cache_cpu *c;
3714 unsigned long tid;
3715 void **freelist;
3716
3717redo:
3718 /*
3719 * Determine the currently cpus per cpu slab.
3720 * The cpu may change afterward. However that does not matter since
3721 * data is retrieved via this pointer. If we are on the same cpu
3722 * during the cmpxchg then the free will succeed.
3723 */
3724 c = raw_cpu_ptr(s->cpu_slab);
3725 tid = READ_ONCE(c->tid);
3726
3727 /* Same with comment on barrier() in slab_alloc_node() */
3728 barrier();
3729
3730 if (unlikely(slab != c->slab)) {
3731 __slab_free(s, slab, head, tail_obj, cnt, addr);
3732 return;
3733 }
3734
3735 if (USE_LOCKLESS_FAST_PATH()) {
3736 freelist = READ_ONCE(c->freelist);
3737
3738 set_freepointer(s, tail_obj, freelist);
3739
3740 if (unlikely(!this_cpu_cmpxchg_double(
3741 s->cpu_slab->freelist, s->cpu_slab->tid,
3742 freelist, tid,
3743 head, next_tid(tid)))) {
3744
3745 note_cmpxchg_failure("slab_free", s, tid);
3746 goto redo;
3747 }
3748 } else {
3749 /* Update the free list under the local lock */
3750 local_lock(&s->cpu_slab->lock);
3751 c = this_cpu_ptr(s->cpu_slab);
3752 if (unlikely(slab != c->slab)) {
3753 local_unlock(&s->cpu_slab->lock);
3754 goto redo;
3755 }
3756 tid = c->tid;
3757 freelist = c->freelist;
3758
3759 set_freepointer(s, tail_obj, freelist);
3760 c->freelist = head;
3761 c->tid = next_tid(tid);
3762
3763 local_unlock(&s->cpu_slab->lock);
3764 }
3765 stat(s, FREE_FASTPATH);
3766}
3767#else /* CONFIG_SLUB_TINY */
3768static void do_slab_free(struct kmem_cache *s,
3769 struct slab *slab, void *head, void *tail,
3770 int cnt, unsigned long addr)
3771{
3772 void *tail_obj = tail ? : head;
3773
3774 __slab_free(s, slab, head, tail_obj, cnt, addr);
3775}
3776#endif /* CONFIG_SLUB_TINY */
3777
3778static __fastpath_inline void slab_free(struct kmem_cache *s, struct slab *slab,
3779 void *head, void *tail, void **p, int cnt,
3780 unsigned long addr)
3781{
3782 memcg_slab_free_hook(s, slab, p, cnt);
3783 /*
3784 * With KASAN enabled slab_free_freelist_hook modifies the freelist
3785 * to remove objects, whose reuse must be delayed.
3786 */
3787 if (slab_free_freelist_hook(s, &head, &tail, &cnt))
3788 do_slab_free(s, slab, head, tail, cnt, addr);
3789}
3790
3791#ifdef CONFIG_KASAN_GENERIC
3792void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
3793{
3794 do_slab_free(cache, virt_to_slab(x), x, NULL, 1, addr);
3795}
3796#endif
3797
3798void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller)
3799{
3800 slab_free(s, virt_to_slab(x), x, NULL, &x, 1, caller);
3801}
3802
3803void kmem_cache_free(struct kmem_cache *s, void *x)
3804{
3805 s = cache_from_obj(s, x);
3806 if (!s)
3807 return;
3808 trace_kmem_cache_free(_RET_IP_, x, s);
3809 slab_free(s, virt_to_slab(x), x, NULL, &x, 1, _RET_IP_);
3810}
3811EXPORT_SYMBOL(kmem_cache_free);
3812
3813struct detached_freelist {
3814 struct slab *slab;
3815 void *tail;
3816 void *freelist;
3817 int cnt;
3818 struct kmem_cache *s;
3819};
3820
3821/*
3822 * This function progressively scans the array with free objects (with
3823 * a limited look ahead) and extract objects belonging to the same
3824 * slab. It builds a detached freelist directly within the given
3825 * slab/objects. This can happen without any need for
3826 * synchronization, because the objects are owned by running process.
3827 * The freelist is build up as a single linked list in the objects.
3828 * The idea is, that this detached freelist can then be bulk
3829 * transferred to the real freelist(s), but only requiring a single
3830 * synchronization primitive. Look ahead in the array is limited due
3831 * to performance reasons.
3832 */
3833static inline
3834int build_detached_freelist(struct kmem_cache *s, size_t size,
3835 void **p, struct detached_freelist *df)
3836{
3837 int lookahead = 3;
3838 void *object;
3839 struct folio *folio;
3840 size_t same;
3841
3842 object = p[--size];
3843 folio = virt_to_folio(object);
3844 if (!s) {
3845 /* Handle kalloc'ed objects */
3846 if (unlikely(!folio_test_slab(folio))) {
3847 free_large_kmalloc(folio, object);
3848 df->slab = NULL;
3849 return size;
3850 }
3851 /* Derive kmem_cache from object */
3852 df->slab = folio_slab(folio);
3853 df->s = df->slab->slab_cache;
3854 } else {
3855 df->slab = folio_slab(folio);
3856 df->s = cache_from_obj(s, object); /* Support for memcg */
3857 }
3858
3859 /* Start new detached freelist */
3860 df->tail = object;
3861 df->freelist = object;
3862 df->cnt = 1;
3863
3864 if (is_kfence_address(object))
3865 return size;
3866
3867 set_freepointer(df->s, object, NULL);
3868
3869 same = size;
3870 while (size) {
3871 object = p[--size];
3872 /* df->slab is always set at this point */
3873 if (df->slab == virt_to_slab(object)) {
3874 /* Opportunity build freelist */
3875 set_freepointer(df->s, object, df->freelist);
3876 df->freelist = object;
3877 df->cnt++;
3878 same--;
3879 if (size != same)
3880 swap(p[size], p[same]);
3881 continue;
3882 }
3883
3884 /* Limit look ahead search */
3885 if (!--lookahead)
3886 break;
3887 }
3888
3889 return same;
3890}
3891
3892/* Note that interrupts must be enabled when calling this function. */
3893void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3894{
3895 if (!size)
3896 return;
3897
3898 do {
3899 struct detached_freelist df;
3900
3901 size = build_detached_freelist(s, size, p, &df);
3902 if (!df.slab)
3903 continue;
3904
3905 slab_free(df.s, df.slab, df.freelist, df.tail, &p[size], df.cnt,
3906 _RET_IP_);
3907 } while (likely(size));
3908}
3909EXPORT_SYMBOL(kmem_cache_free_bulk);
3910
3911#ifndef CONFIG_SLUB_TINY
3912static inline int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
3913 size_t size, void **p, struct obj_cgroup *objcg)
3914{
3915 struct kmem_cache_cpu *c;
3916 int i;
3917
3918 /*
3919 * Drain objects in the per cpu slab, while disabling local
3920 * IRQs, which protects against PREEMPT and interrupts
3921 * handlers invoking normal fastpath.
3922 */
3923 c = slub_get_cpu_ptr(s->cpu_slab);
3924 local_lock_irq(&s->cpu_slab->lock);
3925
3926 for (i = 0; i < size; i++) {
3927 void *object = kfence_alloc(s, s->object_size, flags);
3928
3929 if (unlikely(object)) {
3930 p[i] = object;
3931 continue;
3932 }
3933
3934 object = c->freelist;
3935 if (unlikely(!object)) {
3936 /*
3937 * We may have removed an object from c->freelist using
3938 * the fastpath in the previous iteration; in that case,
3939 * c->tid has not been bumped yet.
3940 * Since ___slab_alloc() may reenable interrupts while
3941 * allocating memory, we should bump c->tid now.
3942 */
3943 c->tid = next_tid(c->tid);
3944
3945 local_unlock_irq(&s->cpu_slab->lock);
3946
3947 /*
3948 * Invoking slow path likely have side-effect
3949 * of re-populating per CPU c->freelist
3950 */
3951 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3952 _RET_IP_, c, s->object_size);
3953 if (unlikely(!p[i]))
3954 goto error;
3955
3956 c = this_cpu_ptr(s->cpu_slab);
3957 maybe_wipe_obj_freeptr(s, p[i]);
3958
3959 local_lock_irq(&s->cpu_slab->lock);
3960
3961 continue; /* goto for-loop */
3962 }
3963 c->freelist = get_freepointer(s, object);
3964 p[i] = object;
3965 maybe_wipe_obj_freeptr(s, p[i]);
3966 }
3967 c->tid = next_tid(c->tid);
3968 local_unlock_irq(&s->cpu_slab->lock);
3969 slub_put_cpu_ptr(s->cpu_slab);
3970
3971 return i;
3972
3973error:
3974 slub_put_cpu_ptr(s->cpu_slab);
3975 slab_post_alloc_hook(s, objcg, flags, i, p, false, s->object_size);
3976 kmem_cache_free_bulk(s, i, p);
3977 return 0;
3978
3979}
3980#else /* CONFIG_SLUB_TINY */
3981static int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
3982 size_t size, void **p, struct obj_cgroup *objcg)
3983{
3984 int i;
3985
3986 for (i = 0; i < size; i++) {
3987 void *object = kfence_alloc(s, s->object_size, flags);
3988
3989 if (unlikely(object)) {
3990 p[i] = object;
3991 continue;
3992 }
3993
3994 p[i] = __slab_alloc_node(s, flags, NUMA_NO_NODE,
3995 _RET_IP_, s->object_size);
3996 if (unlikely(!p[i]))
3997 goto error;
3998
3999 maybe_wipe_obj_freeptr(s, p[i]);
4000 }
4001
4002 return i;
4003
4004error:
4005 slab_post_alloc_hook(s, objcg, flags, i, p, false, s->object_size);
4006 kmem_cache_free_bulk(s, i, p);
4007 return 0;
4008}
4009#endif /* CONFIG_SLUB_TINY */
4010
4011/* Note that interrupts must be enabled when calling this function. */
4012int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
4013 void **p)
4014{
4015 int i;
4016 struct obj_cgroup *objcg = NULL;
4017
4018 if (!size)
4019 return 0;
4020
4021 /* memcg and kmem_cache debug support */
4022 s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
4023 if (unlikely(!s))
4024 return 0;
4025
4026 i = __kmem_cache_alloc_bulk(s, flags, size, p, objcg);
4027
4028 /*
4029 * memcg and kmem_cache debug support and memory initialization.
4030 * Done outside of the IRQ disabled fastpath loop.
4031 */
4032 if (i != 0)
4033 slab_post_alloc_hook(s, objcg, flags, size, p,
4034 slab_want_init_on_alloc(flags, s), s->object_size);
4035 return i;
4036}
4037EXPORT_SYMBOL(kmem_cache_alloc_bulk);
4038
4039
4040/*
4041 * Object placement in a slab is made very easy because we always start at
4042 * offset 0. If we tune the size of the object to the alignment then we can
4043 * get the required alignment by putting one properly sized object after
4044 * another.
4045 *
4046 * Notice that the allocation order determines the sizes of the per cpu
4047 * caches. Each processor has always one slab available for allocations.
4048 * Increasing the allocation order reduces the number of times that slabs
4049 * must be moved on and off the partial lists and is therefore a factor in
4050 * locking overhead.
4051 */
4052
4053/*
4054 * Minimum / Maximum order of slab pages. This influences locking overhead
4055 * and slab fragmentation. A higher order reduces the number of partial slabs
4056 * and increases the number of allocations possible without having to
4057 * take the list_lock.
4058 */
4059static unsigned int slub_min_order;
4060static unsigned int slub_max_order =
4061 IS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;
4062static unsigned int slub_min_objects;
4063
4064/*
4065 * Calculate the order of allocation given an slab object size.
4066 *
4067 * The order of allocation has significant impact on performance and other
4068 * system components. Generally order 0 allocations should be preferred since
4069 * order 0 does not cause fragmentation in the page allocator. Larger objects
4070 * be problematic to put into order 0 slabs because there may be too much
4071 * unused space left. We go to a higher order if more than 1/16th of the slab
4072 * would be wasted.
4073 *
4074 * In order to reach satisfactory performance we must ensure that a minimum
4075 * number of objects is in one slab. Otherwise we may generate too much
4076 * activity on the partial lists which requires taking the list_lock. This is
4077 * less a concern for large slabs though which are rarely used.
4078 *
4079 * slub_max_order specifies the order where we begin to stop considering the
4080 * number of objects in a slab as critical. If we reach slub_max_order then
4081 * we try to keep the page order as low as possible. So we accept more waste
4082 * of space in favor of a small page order.
4083 *
4084 * Higher order allocations also allow the placement of more objects in a
4085 * slab and thereby reduce object handling overhead. If the user has
4086 * requested a higher minimum order then we start with that one instead of
4087 * the smallest order which will fit the object.
4088 */
4089static inline unsigned int calc_slab_order(unsigned int size,
4090 unsigned int min_objects, unsigned int max_order,
4091 unsigned int fract_leftover)
4092{
4093 unsigned int min_order = slub_min_order;
4094 unsigned int order;
4095
4096 if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
4097 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
4098
4099 for (order = max(min_order, (unsigned int)get_order(min_objects * size));
4100 order <= max_order; order++) {
4101
4102 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
4103 unsigned int rem;
4104
4105 rem = slab_size % size;
4106
4107 if (rem <= slab_size / fract_leftover)
4108 break;
4109 }
4110
4111 return order;
4112}
4113
4114static inline int calculate_order(unsigned int size)
4115{
4116 unsigned int order;
4117 unsigned int min_objects;
4118 unsigned int max_objects;
4119 unsigned int nr_cpus;
4120
4121 /*
4122 * Attempt to find best configuration for a slab. This
4123 * works by first attempting to generate a layout with
4124 * the best configuration and backing off gradually.
4125 *
4126 * First we increase the acceptable waste in a slab. Then
4127 * we reduce the minimum objects required in a slab.
4128 */
4129 min_objects = slub_min_objects;
4130 if (!min_objects) {
4131 /*
4132 * Some architectures will only update present cpus when
4133 * onlining them, so don't trust the number if it's just 1. But
4134 * we also don't want to use nr_cpu_ids always, as on some other
4135 * architectures, there can be many possible cpus, but never
4136 * onlined. Here we compromise between trying to avoid too high
4137 * order on systems that appear larger than they are, and too
4138 * low order on systems that appear smaller than they are.
4139 */
4140 nr_cpus = num_present_cpus();
4141 if (nr_cpus <= 1)
4142 nr_cpus = nr_cpu_ids;
4143 min_objects = 4 * (fls(nr_cpus) + 1);
4144 }
4145 max_objects = order_objects(slub_max_order, size);
4146 min_objects = min(min_objects, max_objects);
4147
4148 while (min_objects > 1) {
4149 unsigned int fraction;
4150
4151 fraction = 16;
4152 while (fraction >= 4) {
4153 order = calc_slab_order(size, min_objects,
4154 slub_max_order, fraction);
4155 if (order <= slub_max_order)
4156 return order;
4157 fraction /= 2;
4158 }
4159 min_objects--;
4160 }
4161
4162 /*
4163 * We were unable to place multiple objects in a slab. Now
4164 * lets see if we can place a single object there.
4165 */
4166 order = calc_slab_order(size, 1, slub_max_order, 1);
4167 if (order <= slub_max_order)
4168 return order;
4169
4170 /*
4171 * Doh this slab cannot be placed using slub_max_order.
4172 */
4173 order = calc_slab_order(size, 1, MAX_ORDER, 1);
4174 if (order < MAX_ORDER)
4175 return order;
4176 return -ENOSYS;
4177}
4178
4179static void
4180init_kmem_cache_node(struct kmem_cache_node *n)
4181{
4182 n->nr_partial = 0;
4183 spin_lock_init(&n->list_lock);
4184 INIT_LIST_HEAD(&n->partial);
4185#ifdef CONFIG_SLUB_DEBUG
4186 atomic_long_set(&n->nr_slabs, 0);
4187 atomic_long_set(&n->total_objects, 0);
4188 INIT_LIST_HEAD(&n->full);
4189#endif
4190}
4191
4192#ifndef CONFIG_SLUB_TINY
4193static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4194{
4195 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
4196 NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
4197 sizeof(struct kmem_cache_cpu));
4198
4199 /*
4200 * Must align to double word boundary for the double cmpxchg
4201 * instructions to work; see __pcpu_double_call_return_bool().
4202 */
4203 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
4204 2 * sizeof(void *));
4205
4206 if (!s->cpu_slab)
4207 return 0;
4208
4209 init_kmem_cache_cpus(s);
4210
4211 return 1;
4212}
4213#else
4214static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4215{
4216 return 1;
4217}
4218#endif /* CONFIG_SLUB_TINY */
4219
4220static struct kmem_cache *kmem_cache_node;
4221
4222/*
4223 * No kmalloc_node yet so do it by hand. We know that this is the first
4224 * slab on the node for this slabcache. There are no concurrent accesses
4225 * possible.
4226 *
4227 * Note that this function only works on the kmem_cache_node
4228 * when allocating for the kmem_cache_node. This is used for bootstrapping
4229 * memory on a fresh node that has no slab structures yet.
4230 */
4231static void early_kmem_cache_node_alloc(int node)
4232{
4233 struct slab *slab;
4234 struct kmem_cache_node *n;
4235
4236 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
4237
4238 slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
4239
4240 BUG_ON(!slab);
4241 inc_slabs_node(kmem_cache_node, slab_nid(slab), slab->objects);
4242 if (slab_nid(slab) != node) {
4243 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
4244 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
4245 }
4246
4247 n = slab->freelist;
4248 BUG_ON(!n);
4249#ifdef CONFIG_SLUB_DEBUG
4250 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
4251 init_tracking(kmem_cache_node, n);
4252#endif
4253 n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
4254 slab->freelist = get_freepointer(kmem_cache_node, n);
4255 slab->inuse = 1;
4256 kmem_cache_node->node[node] = n;
4257 init_kmem_cache_node(n);
4258 inc_slabs_node(kmem_cache_node, node, slab->objects);
4259
4260 /*
4261 * No locks need to be taken here as it has just been
4262 * initialized and there is no concurrent access.
4263 */
4264 __add_partial(n, slab, DEACTIVATE_TO_HEAD);
4265}
4266
4267static void free_kmem_cache_nodes(struct kmem_cache *s)
4268{
4269 int node;
4270 struct kmem_cache_node *n;
4271
4272 for_each_kmem_cache_node(s, node, n) {
4273 s->node[node] = NULL;
4274 kmem_cache_free(kmem_cache_node, n);
4275 }
4276}
4277
4278void __kmem_cache_release(struct kmem_cache *s)
4279{
4280 cache_random_seq_destroy(s);
4281#ifndef CONFIG_SLUB_TINY
4282 free_percpu(s->cpu_slab);
4283#endif
4284 free_kmem_cache_nodes(s);
4285}
4286
4287static int init_kmem_cache_nodes(struct kmem_cache *s)
4288{
4289 int node;
4290
4291 for_each_node_mask(node, slab_nodes) {
4292 struct kmem_cache_node *n;
4293
4294 if (slab_state == DOWN) {
4295 early_kmem_cache_node_alloc(node);
4296 continue;
4297 }
4298 n = kmem_cache_alloc_node(kmem_cache_node,
4299 GFP_KERNEL, node);
4300
4301 if (!n) {
4302 free_kmem_cache_nodes(s);
4303 return 0;
4304 }
4305
4306 init_kmem_cache_node(n);
4307 s->node[node] = n;
4308 }
4309 return 1;
4310}
4311
4312static void set_cpu_partial(struct kmem_cache *s)
4313{
4314#ifdef CONFIG_SLUB_CPU_PARTIAL
4315 unsigned int nr_objects;
4316
4317 /*
4318 * cpu_partial determined the maximum number of objects kept in the
4319 * per cpu partial lists of a processor.
4320 *
4321 * Per cpu partial lists mainly contain slabs that just have one
4322 * object freed. If they are used for allocation then they can be
4323 * filled up again with minimal effort. The slab will never hit the
4324 * per node partial lists and therefore no locking will be required.
4325 *
4326 * For backwards compatibility reasons, this is determined as number
4327 * of objects, even though we now limit maximum number of pages, see
4328 * slub_set_cpu_partial()
4329 */
4330 if (!kmem_cache_has_cpu_partial(s))
4331 nr_objects = 0;
4332 else if (s->size >= PAGE_SIZE)
4333 nr_objects = 6;
4334 else if (s->size >= 1024)
4335 nr_objects = 24;
4336 else if (s->size >= 256)
4337 nr_objects = 52;
4338 else
4339 nr_objects = 120;
4340
4341 slub_set_cpu_partial(s, nr_objects);
4342#endif
4343}
4344
4345/*
4346 * calculate_sizes() determines the order and the distribution of data within
4347 * a slab object.
4348 */
4349static int calculate_sizes(struct kmem_cache *s)
4350{
4351 slab_flags_t flags = s->flags;
4352 unsigned int size = s->object_size;
4353 unsigned int order;
4354
4355 /*
4356 * Round up object size to the next word boundary. We can only
4357 * place the free pointer at word boundaries and this determines
4358 * the possible location of the free pointer.
4359 */
4360 size = ALIGN(size, sizeof(void *));
4361
4362#ifdef CONFIG_SLUB_DEBUG
4363 /*
4364 * Determine if we can poison the object itself. If the user of
4365 * the slab may touch the object after free or before allocation
4366 * then we should never poison the object itself.
4367 */
4368 if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
4369 !s->ctor)
4370 s->flags |= __OBJECT_POISON;
4371 else
4372 s->flags &= ~__OBJECT_POISON;
4373
4374
4375 /*
4376 * If we are Redzoning then check if there is some space between the
4377 * end of the object and the free pointer. If not then add an
4378 * additional word to have some bytes to store Redzone information.
4379 */
4380 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
4381 size += sizeof(void *);
4382#endif
4383
4384 /*
4385 * With that we have determined the number of bytes in actual use
4386 * by the object and redzoning.
4387 */
4388 s->inuse = size;
4389
4390 if (slub_debug_orig_size(s) ||
4391 (flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
4392 ((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) ||
4393 s->ctor) {
4394 /*
4395 * Relocate free pointer after the object if it is not
4396 * permitted to overwrite the first word of the object on
4397 * kmem_cache_free.
4398 *
4399 * This is the case if we do RCU, have a constructor or
4400 * destructor, are poisoning the objects, or are
4401 * redzoning an object smaller than sizeof(void *).
4402 *
4403 * The assumption that s->offset >= s->inuse means free
4404 * pointer is outside of the object is used in the
4405 * freeptr_outside_object() function. If that is no
4406 * longer true, the function needs to be modified.
4407 */
4408 s->offset = size;
4409 size += sizeof(void *);
4410 } else {
4411 /*
4412 * Store freelist pointer near middle of object to keep
4413 * it away from the edges of the object to avoid small
4414 * sized over/underflows from neighboring allocations.
4415 */
4416 s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
4417 }
4418
4419#ifdef CONFIG_SLUB_DEBUG
4420 if (flags & SLAB_STORE_USER) {
4421 /*
4422 * Need to store information about allocs and frees after
4423 * the object.
4424 */
4425 size += 2 * sizeof(struct track);
4426
4427 /* Save the original kmalloc request size */
4428 if (flags & SLAB_KMALLOC)
4429 size += sizeof(unsigned int);
4430 }
4431#endif
4432
4433 kasan_cache_create(s, &size, &s->flags);
4434#ifdef CONFIG_SLUB_DEBUG
4435 if (flags & SLAB_RED_ZONE) {
4436 /*
4437 * Add some empty padding so that we can catch
4438 * overwrites from earlier objects rather than let
4439 * tracking information or the free pointer be
4440 * corrupted if a user writes before the start
4441 * of the object.
4442 */
4443 size += sizeof(void *);
4444
4445 s->red_left_pad = sizeof(void *);
4446 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
4447 size += s->red_left_pad;
4448 }
4449#endif
4450
4451 /*
4452 * SLUB stores one object immediately after another beginning from
4453 * offset 0. In order to align the objects we have to simply size
4454 * each object to conform to the alignment.
4455 */
4456 size = ALIGN(size, s->align);
4457 s->size = size;
4458 s->reciprocal_size = reciprocal_value(size);
4459 order = calculate_order(size);
4460
4461 if ((int)order < 0)
4462 return 0;
4463
4464 s->allocflags = 0;
4465 if (order)
4466 s->allocflags |= __GFP_COMP;
4467
4468 if (s->flags & SLAB_CACHE_DMA)
4469 s->allocflags |= GFP_DMA;
4470
4471 if (s->flags & SLAB_CACHE_DMA32)
4472 s->allocflags |= GFP_DMA32;
4473
4474 if (s->flags & SLAB_RECLAIM_ACCOUNT)
4475 s->allocflags |= __GFP_RECLAIMABLE;
4476
4477 /*
4478 * Determine the number of objects per slab
4479 */
4480 s->oo = oo_make(order, size);
4481 s->min = oo_make(get_order(size), size);
4482
4483 return !!oo_objects(s->oo);
4484}
4485
4486static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
4487{
4488 s->flags = kmem_cache_flags(s->size, flags, s->name);
4489#ifdef CONFIG_SLAB_FREELIST_HARDENED
4490 s->random = get_random_long();
4491#endif
4492
4493 if (!calculate_sizes(s))
4494 goto error;
4495 if (disable_higher_order_debug) {
4496 /*
4497 * Disable debugging flags that store metadata if the min slab
4498 * order increased.
4499 */
4500 if (get_order(s->size) > get_order(s->object_size)) {
4501 s->flags &= ~DEBUG_METADATA_FLAGS;
4502 s->offset = 0;
4503 if (!calculate_sizes(s))
4504 goto error;
4505 }
4506 }
4507
4508#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
4509 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
4510 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
4511 /* Enable fast mode */
4512 s->flags |= __CMPXCHG_DOUBLE;
4513#endif
4514
4515 /*
4516 * The larger the object size is, the more slabs we want on the partial
4517 * list to avoid pounding the page allocator excessively.
4518 */
4519 s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
4520 s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
4521
4522 set_cpu_partial(s);
4523
4524#ifdef CONFIG_NUMA
4525 s->remote_node_defrag_ratio = 1000;
4526#endif
4527
4528 /* Initialize the pre-computed randomized freelist if slab is up */
4529 if (slab_state >= UP) {
4530 if (init_cache_random_seq(s))
4531 goto error;
4532 }
4533
4534 if (!init_kmem_cache_nodes(s))
4535 goto error;
4536
4537 if (alloc_kmem_cache_cpus(s))
4538 return 0;
4539
4540error:
4541 __kmem_cache_release(s);
4542 return -EINVAL;
4543}
4544
4545static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
4546 const char *text)
4547{
4548#ifdef CONFIG_SLUB_DEBUG
4549 void *addr = slab_address(slab);
4550 void *p;
4551
4552 slab_err(s, slab, text, s->name);
4553
4554 spin_lock(&object_map_lock);
4555 __fill_map(object_map, s, slab);
4556
4557 for_each_object(p, s, addr, slab->objects) {
4558
4559 if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
4560 pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
4561 print_tracking(s, p);
4562 }
4563 }
4564 spin_unlock(&object_map_lock);
4565#endif
4566}
4567
4568/*
4569 * Attempt to free all partial slabs on a node.
4570 * This is called from __kmem_cache_shutdown(). We must take list_lock
4571 * because sysfs file might still access partial list after the shutdowning.
4572 */
4573static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
4574{
4575 LIST_HEAD(discard);
4576 struct slab *slab, *h;
4577
4578 BUG_ON(irqs_disabled());
4579 spin_lock_irq(&n->list_lock);
4580 list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
4581 if (!slab->inuse) {
4582 remove_partial(n, slab);
4583 list_add(&slab->slab_list, &discard);
4584 } else {
4585 list_slab_objects(s, slab,
4586 "Objects remaining in %s on __kmem_cache_shutdown()");
4587 }
4588 }
4589 spin_unlock_irq(&n->list_lock);
4590
4591 list_for_each_entry_safe(slab, h, &discard, slab_list)
4592 discard_slab(s, slab);
4593}
4594
4595bool __kmem_cache_empty(struct kmem_cache *s)
4596{
4597 int node;
4598 struct kmem_cache_node *n;
4599
4600 for_each_kmem_cache_node(s, node, n)
4601 if (n->nr_partial || slabs_node(s, node))
4602 return false;
4603 return true;
4604}
4605
4606/*
4607 * Release all resources used by a slab cache.
4608 */
4609int __kmem_cache_shutdown(struct kmem_cache *s)
4610{
4611 int node;
4612 struct kmem_cache_node *n;
4613
4614 flush_all_cpus_locked(s);
4615 /* Attempt to free all objects */
4616 for_each_kmem_cache_node(s, node, n) {
4617 free_partial(s, n);
4618 if (n->nr_partial || slabs_node(s, node))
4619 return 1;
4620 }
4621 return 0;
4622}
4623
4624#ifdef CONFIG_PRINTK
4625void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
4626{
4627 void *base;
4628 int __maybe_unused i;
4629 unsigned int objnr;
4630 void *objp;
4631 void *objp0;
4632 struct kmem_cache *s = slab->slab_cache;
4633 struct track __maybe_unused *trackp;
4634
4635 kpp->kp_ptr = object;
4636 kpp->kp_slab = slab;
4637 kpp->kp_slab_cache = s;
4638 base = slab_address(slab);
4639 objp0 = kasan_reset_tag(object);
4640#ifdef CONFIG_SLUB_DEBUG
4641 objp = restore_red_left(s, objp0);
4642#else
4643 objp = objp0;
4644#endif
4645 objnr = obj_to_index(s, slab, objp);
4646 kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
4647 objp = base + s->size * objnr;
4648 kpp->kp_objp = objp;
4649 if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
4650 || (objp - base) % s->size) ||
4651 !(s->flags & SLAB_STORE_USER))
4652 return;
4653#ifdef CONFIG_SLUB_DEBUG
4654 objp = fixup_red_left(s, objp);
4655 trackp = get_track(s, objp, TRACK_ALLOC);
4656 kpp->kp_ret = (void *)trackp->addr;
4657#ifdef CONFIG_STACKDEPOT
4658 {
4659 depot_stack_handle_t handle;
4660 unsigned long *entries;
4661 unsigned int nr_entries;
4662
4663 handle = READ_ONCE(trackp->handle);
4664 if (handle) {
4665 nr_entries = stack_depot_fetch(handle, &entries);
4666 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
4667 kpp->kp_stack[i] = (void *)entries[i];
4668 }
4669
4670 trackp = get_track(s, objp, TRACK_FREE);
4671 handle = READ_ONCE(trackp->handle);
4672 if (handle) {
4673 nr_entries = stack_depot_fetch(handle, &entries);
4674 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
4675 kpp->kp_free_stack[i] = (void *)entries[i];
4676 }
4677 }
4678#endif
4679#endif
4680}
4681#endif
4682
4683/********************************************************************
4684 * Kmalloc subsystem
4685 *******************************************************************/
4686
4687static int __init setup_slub_min_order(char *str)
4688{
4689 get_option(&str, (int *)&slub_min_order);
4690
4691 return 1;
4692}
4693
4694__setup("slub_min_order=", setup_slub_min_order);
4695
4696static int __init setup_slub_max_order(char *str)
4697{
4698 get_option(&str, (int *)&slub_max_order);
4699 slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
4700
4701 return 1;
4702}
4703
4704__setup("slub_max_order=", setup_slub_max_order);
4705
4706static int __init setup_slub_min_objects(char *str)
4707{
4708 get_option(&str, (int *)&slub_min_objects);
4709
4710 return 1;
4711}
4712
4713__setup("slub_min_objects=", setup_slub_min_objects);
4714
4715#ifdef CONFIG_HARDENED_USERCOPY
4716/*
4717 * Rejects incorrectly sized objects and objects that are to be copied
4718 * to/from userspace but do not fall entirely within the containing slab
4719 * cache's usercopy region.
4720 *
4721 * Returns NULL if check passes, otherwise const char * to name of cache
4722 * to indicate an error.
4723 */
4724void __check_heap_object(const void *ptr, unsigned long n,
4725 const struct slab *slab, bool to_user)
4726{
4727 struct kmem_cache *s;
4728 unsigned int offset;
4729 bool is_kfence = is_kfence_address(ptr);
4730
4731 ptr = kasan_reset_tag(ptr);
4732
4733 /* Find object and usable object size. */
4734 s = slab->slab_cache;
4735
4736 /* Reject impossible pointers. */
4737 if (ptr < slab_address(slab))
4738 usercopy_abort("SLUB object not in SLUB page?!", NULL,
4739 to_user, 0, n);
4740
4741 /* Find offset within object. */
4742 if (is_kfence)
4743 offset = ptr - kfence_object_start(ptr);
4744 else
4745 offset = (ptr - slab_address(slab)) % s->size;
4746
4747 /* Adjust for redzone and reject if within the redzone. */
4748 if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
4749 if (offset < s->red_left_pad)
4750 usercopy_abort("SLUB object in left red zone",
4751 s->name, to_user, offset, n);
4752 offset -= s->red_left_pad;
4753 }
4754
4755 /* Allow address range falling entirely within usercopy region. */
4756 if (offset >= s->useroffset &&
4757 offset - s->useroffset <= s->usersize &&
4758 n <= s->useroffset - offset + s->usersize)
4759 return;
4760
4761 usercopy_abort("SLUB object", s->name, to_user, offset, n);
4762}
4763#endif /* CONFIG_HARDENED_USERCOPY */
4764
4765#define SHRINK_PROMOTE_MAX 32
4766
4767/*
4768 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
4769 * up most to the head of the partial lists. New allocations will then
4770 * fill those up and thus they can be removed from the partial lists.
4771 *
4772 * The slabs with the least items are placed last. This results in them
4773 * being allocated from last increasing the chance that the last objects
4774 * are freed in them.
4775 */
4776static int __kmem_cache_do_shrink(struct kmem_cache *s)
4777{
4778 int node;
4779 int i;
4780 struct kmem_cache_node *n;
4781 struct slab *slab;
4782 struct slab *t;
4783 struct list_head discard;
4784 struct list_head promote[SHRINK_PROMOTE_MAX];
4785 unsigned long flags;
4786 int ret = 0;
4787
4788 for_each_kmem_cache_node(s, node, n) {
4789 INIT_LIST_HEAD(&discard);
4790 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
4791 INIT_LIST_HEAD(promote + i);
4792
4793 spin_lock_irqsave(&n->list_lock, flags);
4794
4795 /*
4796 * Build lists of slabs to discard or promote.
4797 *
4798 * Note that concurrent frees may occur while we hold the
4799 * list_lock. slab->inuse here is the upper limit.
4800 */
4801 list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
4802 int free = slab->objects - slab->inuse;
4803
4804 /* Do not reread slab->inuse */
4805 barrier();
4806
4807 /* We do not keep full slabs on the list */
4808 BUG_ON(free <= 0);
4809
4810 if (free == slab->objects) {
4811 list_move(&slab->slab_list, &discard);
4812 n->nr_partial--;
4813 dec_slabs_node(s, node, slab->objects);
4814 } else if (free <= SHRINK_PROMOTE_MAX)
4815 list_move(&slab->slab_list, promote + free - 1);
4816 }
4817
4818 /*
4819 * Promote the slabs filled up most to the head of the
4820 * partial list.
4821 */
4822 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
4823 list_splice(promote + i, &n->partial);
4824
4825 spin_unlock_irqrestore(&n->list_lock, flags);
4826
4827 /* Release empty slabs */
4828 list_for_each_entry_safe(slab, t, &discard, slab_list)
4829 free_slab(s, slab);
4830
4831 if (slabs_node(s, node))
4832 ret = 1;
4833 }
4834
4835 return ret;
4836}
4837
4838int __kmem_cache_shrink(struct kmem_cache *s)
4839{
4840 flush_all(s);
4841 return __kmem_cache_do_shrink(s);
4842}
4843
4844static int slab_mem_going_offline_callback(void *arg)
4845{
4846 struct kmem_cache *s;
4847
4848 mutex_lock(&slab_mutex);
4849 list_for_each_entry(s, &slab_caches, list) {
4850 flush_all_cpus_locked(s);
4851 __kmem_cache_do_shrink(s);
4852 }
4853 mutex_unlock(&slab_mutex);
4854
4855 return 0;
4856}
4857
4858static void slab_mem_offline_callback(void *arg)
4859{
4860 struct memory_notify *marg = arg;
4861 int offline_node;
4862
4863 offline_node = marg->status_change_nid_normal;
4864
4865 /*
4866 * If the node still has available memory. we need kmem_cache_node
4867 * for it yet.
4868 */
4869 if (offline_node < 0)
4870 return;
4871
4872 mutex_lock(&slab_mutex);
4873 node_clear(offline_node, slab_nodes);
4874 /*
4875 * We no longer free kmem_cache_node structures here, as it would be
4876 * racy with all get_node() users, and infeasible to protect them with
4877 * slab_mutex.
4878 */
4879 mutex_unlock(&slab_mutex);
4880}
4881
4882static int slab_mem_going_online_callback(void *arg)
4883{
4884 struct kmem_cache_node *n;
4885 struct kmem_cache *s;
4886 struct memory_notify *marg = arg;
4887 int nid = marg->status_change_nid_normal;
4888 int ret = 0;
4889
4890 /*
4891 * If the node's memory is already available, then kmem_cache_node is
4892 * already created. Nothing to do.
4893 */
4894 if (nid < 0)
4895 return 0;
4896
4897 /*
4898 * We are bringing a node online. No memory is available yet. We must
4899 * allocate a kmem_cache_node structure in order to bring the node
4900 * online.
4901 */
4902 mutex_lock(&slab_mutex);
4903 list_for_each_entry(s, &slab_caches, list) {
4904 /*
4905 * The structure may already exist if the node was previously
4906 * onlined and offlined.
4907 */
4908 if (get_node(s, nid))
4909 continue;
4910 /*
4911 * XXX: kmem_cache_alloc_node will fallback to other nodes
4912 * since memory is not yet available from the node that
4913 * is brought up.
4914 */
4915 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4916 if (!n) {
4917 ret = -ENOMEM;
4918 goto out;
4919 }
4920 init_kmem_cache_node(n);
4921 s->node[nid] = n;
4922 }
4923 /*
4924 * Any cache created after this point will also have kmem_cache_node
4925 * initialized for the new node.
4926 */
4927 node_set(nid, slab_nodes);
4928out:
4929 mutex_unlock(&slab_mutex);
4930 return ret;
4931}
4932
4933static int slab_memory_callback(struct notifier_block *self,
4934 unsigned long action, void *arg)
4935{
4936 int ret = 0;
4937
4938 switch (action) {
4939 case MEM_GOING_ONLINE:
4940 ret = slab_mem_going_online_callback(arg);
4941 break;
4942 case MEM_GOING_OFFLINE:
4943 ret = slab_mem_going_offline_callback(arg);
4944 break;
4945 case MEM_OFFLINE:
4946 case MEM_CANCEL_ONLINE:
4947 slab_mem_offline_callback(arg);
4948 break;
4949 case MEM_ONLINE:
4950 case MEM_CANCEL_OFFLINE:
4951 break;
4952 }
4953 if (ret)
4954 ret = notifier_from_errno(ret);
4955 else
4956 ret = NOTIFY_OK;
4957 return ret;
4958}
4959
4960/********************************************************************
4961 * Basic setup of slabs
4962 *******************************************************************/
4963
4964/*
4965 * Used for early kmem_cache structures that were allocated using
4966 * the page allocator. Allocate them properly then fix up the pointers
4967 * that may be pointing to the wrong kmem_cache structure.
4968 */
4969
4970static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4971{
4972 int node;
4973 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4974 struct kmem_cache_node *n;
4975
4976 memcpy(s, static_cache, kmem_cache->object_size);
4977
4978 /*
4979 * This runs very early, and only the boot processor is supposed to be
4980 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4981 * IPIs around.
4982 */
4983 __flush_cpu_slab(s, smp_processor_id());
4984 for_each_kmem_cache_node(s, node, n) {
4985 struct slab *p;
4986
4987 list_for_each_entry(p, &n->partial, slab_list)
4988 p->slab_cache = s;
4989
4990#ifdef CONFIG_SLUB_DEBUG
4991 list_for_each_entry(p, &n->full, slab_list)
4992 p->slab_cache = s;
4993#endif
4994 }
4995 list_add(&s->list, &slab_caches);
4996 return s;
4997}
4998
4999void __init kmem_cache_init(void)
5000{
5001 static __initdata struct kmem_cache boot_kmem_cache,
5002 boot_kmem_cache_node;
5003 int node;
5004
5005 if (debug_guardpage_minorder())
5006 slub_max_order = 0;
5007
5008 /* Print slub debugging pointers without hashing */
5009 if (__slub_debug_enabled())
5010 no_hash_pointers_enable(NULL);
5011
5012 kmem_cache_node = &boot_kmem_cache_node;
5013 kmem_cache = &boot_kmem_cache;
5014
5015 /*
5016 * Initialize the nodemask for which we will allocate per node
5017 * structures. Here we don't need taking slab_mutex yet.
5018 */
5019 for_each_node_state(node, N_NORMAL_MEMORY)
5020 node_set(node, slab_nodes);
5021
5022 create_boot_cache(kmem_cache_node, "kmem_cache_node",
5023 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
5024
5025 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
5026
5027 /* Able to allocate the per node structures */
5028 slab_state = PARTIAL;
5029
5030 create_boot_cache(kmem_cache, "kmem_cache",
5031 offsetof(struct kmem_cache, node) +
5032 nr_node_ids * sizeof(struct kmem_cache_node *),
5033 SLAB_HWCACHE_ALIGN, 0, 0);
5034
5035 kmem_cache = bootstrap(&boot_kmem_cache);
5036 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
5037
5038 /* Now we can use the kmem_cache to allocate kmalloc slabs */
5039 setup_kmalloc_cache_index_table();
5040 create_kmalloc_caches(0);
5041
5042 /* Setup random freelists for each cache */
5043 init_freelist_randomization();
5044
5045 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
5046 slub_cpu_dead);
5047
5048 pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
5049 cache_line_size(),
5050 slub_min_order, slub_max_order, slub_min_objects,
5051 nr_cpu_ids, nr_node_ids);
5052}
5053
5054void __init kmem_cache_init_late(void)
5055{
5056#ifndef CONFIG_SLUB_TINY
5057 flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
5058 WARN_ON(!flushwq);
5059#endif
5060}
5061
5062struct kmem_cache *
5063__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
5064 slab_flags_t flags, void (*ctor)(void *))
5065{
5066 struct kmem_cache *s;
5067
5068 s = find_mergeable(size, align, flags, name, ctor);
5069 if (s) {
5070 if (sysfs_slab_alias(s, name))
5071 return NULL;
5072
5073 s->refcount++;
5074
5075 /*
5076 * Adjust the object sizes so that we clear
5077 * the complete object on kzalloc.
5078 */
5079 s->object_size = max(s->object_size, size);
5080 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
5081 }
5082
5083 return s;
5084}
5085
5086int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
5087{
5088 int err;
5089
5090 err = kmem_cache_open(s, flags);
5091 if (err)
5092 return err;
5093
5094 /* Mutex is not taken during early boot */
5095 if (slab_state <= UP)
5096 return 0;
5097
5098 err = sysfs_slab_add(s);
5099 if (err) {
5100 __kmem_cache_release(s);
5101 return err;
5102 }
5103
5104 if (s->flags & SLAB_STORE_USER)
5105 debugfs_slab_add(s);
5106
5107 return 0;
5108}
5109
5110#ifdef SLAB_SUPPORTS_SYSFS
5111static int count_inuse(struct slab *slab)
5112{
5113 return slab->inuse;
5114}
5115
5116static int count_total(struct slab *slab)
5117{
5118 return slab->objects;
5119}
5120#endif
5121
5122#ifdef CONFIG_SLUB_DEBUG
5123static void validate_slab(struct kmem_cache *s, struct slab *slab,
5124 unsigned long *obj_map)
5125{
5126 void *p;
5127 void *addr = slab_address(slab);
5128
5129 if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
5130 return;
5131
5132 /* Now we know that a valid freelist exists */
5133 __fill_map(obj_map, s, slab);
5134 for_each_object(p, s, addr, slab->objects) {
5135 u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
5136 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
5137
5138 if (!check_object(s, slab, p, val))
5139 break;
5140 }
5141}
5142
5143static int validate_slab_node(struct kmem_cache *s,
5144 struct kmem_cache_node *n, unsigned long *obj_map)
5145{
5146 unsigned long count = 0;
5147 struct slab *slab;
5148 unsigned long flags;
5149
5150 spin_lock_irqsave(&n->list_lock, flags);
5151
5152 list_for_each_entry(slab, &n->partial, slab_list) {
5153 validate_slab(s, slab, obj_map);
5154 count++;
5155 }
5156 if (count != n->nr_partial) {
5157 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
5158 s->name, count, n->nr_partial);
5159 slab_add_kunit_errors();
5160 }
5161
5162 if (!(s->flags & SLAB_STORE_USER))
5163 goto out;
5164
5165 list_for_each_entry(slab, &n->full, slab_list) {
5166 validate_slab(s, slab, obj_map);
5167 count++;
5168 }
5169 if (count != atomic_long_read(&n->nr_slabs)) {
5170 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
5171 s->name, count, atomic_long_read(&n->nr_slabs));
5172 slab_add_kunit_errors();
5173 }
5174
5175out:
5176 spin_unlock_irqrestore(&n->list_lock, flags);
5177 return count;
5178}
5179
5180long validate_slab_cache(struct kmem_cache *s)
5181{
5182 int node;
5183 unsigned long count = 0;
5184 struct kmem_cache_node *n;
5185 unsigned long *obj_map;
5186
5187 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
5188 if (!obj_map)
5189 return -ENOMEM;
5190
5191 flush_all(s);
5192 for_each_kmem_cache_node(s, node, n)
5193 count += validate_slab_node(s, n, obj_map);
5194
5195 bitmap_free(obj_map);
5196
5197 return count;
5198}
5199EXPORT_SYMBOL(validate_slab_cache);
5200
5201#ifdef CONFIG_DEBUG_FS
5202/*
5203 * Generate lists of code addresses where slabcache objects are allocated
5204 * and freed.
5205 */
5206
5207struct location {
5208 depot_stack_handle_t handle;
5209 unsigned long count;
5210 unsigned long addr;
5211 unsigned long waste;
5212 long long sum_time;
5213 long min_time;
5214 long max_time;
5215 long min_pid;
5216 long max_pid;
5217 DECLARE_BITMAP(cpus, NR_CPUS);
5218 nodemask_t nodes;
5219};
5220
5221struct loc_track {
5222 unsigned long max;
5223 unsigned long count;
5224 struct location *loc;
5225 loff_t idx;
5226};
5227
5228static struct dentry *slab_debugfs_root;
5229
5230static void free_loc_track(struct loc_track *t)
5231{
5232 if (t->max)
5233 free_pages((unsigned long)t->loc,
5234 get_order(sizeof(struct location) * t->max));
5235}
5236
5237static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
5238{
5239 struct location *l;
5240 int order;
5241
5242 order = get_order(sizeof(struct location) * max);
5243
5244 l = (void *)__get_free_pages(flags, order);
5245 if (!l)
5246 return 0;
5247
5248 if (t->count) {
5249 memcpy(l, t->loc, sizeof(struct location) * t->count);
5250 free_loc_track(t);
5251 }
5252 t->max = max;
5253 t->loc = l;
5254 return 1;
5255}
5256
5257static int add_location(struct loc_track *t, struct kmem_cache *s,
5258 const struct track *track,
5259 unsigned int orig_size)
5260{
5261 long start, end, pos;
5262 struct location *l;
5263 unsigned long caddr, chandle, cwaste;
5264 unsigned long age = jiffies - track->when;
5265 depot_stack_handle_t handle = 0;
5266 unsigned int waste = s->object_size - orig_size;
5267
5268#ifdef CONFIG_STACKDEPOT
5269 handle = READ_ONCE(track->handle);
5270#endif
5271 start = -1;
5272 end = t->count;
5273
5274 for ( ; ; ) {
5275 pos = start + (end - start + 1) / 2;
5276
5277 /*
5278 * There is nothing at "end". If we end up there
5279 * we need to add something to before end.
5280 */
5281 if (pos == end)
5282 break;
5283
5284 l = &t->loc[pos];
5285 caddr = l->addr;
5286 chandle = l->handle;
5287 cwaste = l->waste;
5288 if ((track->addr == caddr) && (handle == chandle) &&
5289 (waste == cwaste)) {
5290
5291 l->count++;
5292 if (track->when) {
5293 l->sum_time += age;
5294 if (age < l->min_time)
5295 l->min_time = age;
5296 if (age > l->max_time)
5297 l->max_time = age;
5298
5299 if (track->pid < l->min_pid)
5300 l->min_pid = track->pid;
5301 if (track->pid > l->max_pid)
5302 l->max_pid = track->pid;
5303
5304 cpumask_set_cpu(track->cpu,
5305 to_cpumask(l->cpus));
5306 }
5307 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5308 return 1;
5309 }
5310
5311 if (track->addr < caddr)
5312 end = pos;
5313 else if (track->addr == caddr && handle < chandle)
5314 end = pos;
5315 else if (track->addr == caddr && handle == chandle &&
5316 waste < cwaste)
5317 end = pos;
5318 else
5319 start = pos;
5320 }
5321
5322 /*
5323 * Not found. Insert new tracking element.
5324 */
5325 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
5326 return 0;
5327
5328 l = t->loc + pos;
5329 if (pos < t->count)
5330 memmove(l + 1, l,
5331 (t->count - pos) * sizeof(struct location));
5332 t->count++;
5333 l->count = 1;
5334 l->addr = track->addr;
5335 l->sum_time = age;
5336 l->min_time = age;
5337 l->max_time = age;
5338 l->min_pid = track->pid;
5339 l->max_pid = track->pid;
5340 l->handle = handle;
5341 l->waste = waste;
5342 cpumask_clear(to_cpumask(l->cpus));
5343 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
5344 nodes_clear(l->nodes);
5345 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5346 return 1;
5347}
5348
5349static void process_slab(struct loc_track *t, struct kmem_cache *s,
5350 struct slab *slab, enum track_item alloc,
5351 unsigned long *obj_map)
5352{
5353 void *addr = slab_address(slab);
5354 bool is_alloc = (alloc == TRACK_ALLOC);
5355 void *p;
5356
5357 __fill_map(obj_map, s, slab);
5358
5359 for_each_object(p, s, addr, slab->objects)
5360 if (!test_bit(__obj_to_index(s, addr, p), obj_map))
5361 add_location(t, s, get_track(s, p, alloc),
5362 is_alloc ? get_orig_size(s, p) :
5363 s->object_size);
5364}
5365#endif /* CONFIG_DEBUG_FS */
5366#endif /* CONFIG_SLUB_DEBUG */
5367
5368#ifdef SLAB_SUPPORTS_SYSFS
5369enum slab_stat_type {
5370 SL_ALL, /* All slabs */
5371 SL_PARTIAL, /* Only partially allocated slabs */
5372 SL_CPU, /* Only slabs used for cpu caches */
5373 SL_OBJECTS, /* Determine allocated objects not slabs */
5374 SL_TOTAL /* Determine object capacity not slabs */
5375};
5376
5377#define SO_ALL (1 << SL_ALL)
5378#define SO_PARTIAL (1 << SL_PARTIAL)
5379#define SO_CPU (1 << SL_CPU)
5380#define SO_OBJECTS (1 << SL_OBJECTS)
5381#define SO_TOTAL (1 << SL_TOTAL)
5382
5383static ssize_t show_slab_objects(struct kmem_cache *s,
5384 char *buf, unsigned long flags)
5385{
5386 unsigned long total = 0;
5387 int node;
5388 int x;
5389 unsigned long *nodes;
5390 int len = 0;
5391
5392 nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
5393 if (!nodes)
5394 return -ENOMEM;
5395
5396 if (flags & SO_CPU) {
5397 int cpu;
5398
5399 for_each_possible_cpu(cpu) {
5400 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
5401 cpu);
5402 int node;
5403 struct slab *slab;
5404
5405 slab = READ_ONCE(c->slab);
5406 if (!slab)
5407 continue;
5408
5409 node = slab_nid(slab);
5410 if (flags & SO_TOTAL)
5411 x = slab->objects;
5412 else if (flags & SO_OBJECTS)
5413 x = slab->inuse;
5414 else
5415 x = 1;
5416
5417 total += x;
5418 nodes[node] += x;
5419
5420#ifdef CONFIG_SLUB_CPU_PARTIAL
5421 slab = slub_percpu_partial_read_once(c);
5422 if (slab) {
5423 node = slab_nid(slab);
5424 if (flags & SO_TOTAL)
5425 WARN_ON_ONCE(1);
5426 else if (flags & SO_OBJECTS)
5427 WARN_ON_ONCE(1);
5428 else
5429 x = slab->slabs;
5430 total += x;
5431 nodes[node] += x;
5432 }
5433#endif
5434 }
5435 }
5436
5437 /*
5438 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
5439 * already held which will conflict with an existing lock order:
5440 *
5441 * mem_hotplug_lock->slab_mutex->kernfs_mutex
5442 *
5443 * We don't really need mem_hotplug_lock (to hold off
5444 * slab_mem_going_offline_callback) here because slab's memory hot
5445 * unplug code doesn't destroy the kmem_cache->node[] data.
5446 */
5447
5448#ifdef CONFIG_SLUB_DEBUG
5449 if (flags & SO_ALL) {
5450 struct kmem_cache_node *n;
5451
5452 for_each_kmem_cache_node(s, node, n) {
5453
5454 if (flags & SO_TOTAL)
5455 x = atomic_long_read(&n->total_objects);
5456 else if (flags & SO_OBJECTS)
5457 x = atomic_long_read(&n->total_objects) -
5458 count_partial(n, count_free);
5459 else
5460 x = atomic_long_read(&n->nr_slabs);
5461 total += x;
5462 nodes[node] += x;
5463 }
5464
5465 } else
5466#endif
5467 if (flags & SO_PARTIAL) {
5468 struct kmem_cache_node *n;
5469
5470 for_each_kmem_cache_node(s, node, n) {
5471 if (flags & SO_TOTAL)
5472 x = count_partial(n, count_total);
5473 else if (flags & SO_OBJECTS)
5474 x = count_partial(n, count_inuse);
5475 else
5476 x = n->nr_partial;
5477 total += x;
5478 nodes[node] += x;
5479 }
5480 }
5481
5482 len += sysfs_emit_at(buf, len, "%lu", total);
5483#ifdef CONFIG_NUMA
5484 for (node = 0; node < nr_node_ids; node++) {
5485 if (nodes[node])
5486 len += sysfs_emit_at(buf, len, " N%d=%lu",
5487 node, nodes[node]);
5488 }
5489#endif
5490 len += sysfs_emit_at(buf, len, "\n");
5491 kfree(nodes);
5492
5493 return len;
5494}
5495
5496#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
5497#define to_slab(n) container_of(n, struct kmem_cache, kobj)
5498
5499struct slab_attribute {
5500 struct attribute attr;
5501 ssize_t (*show)(struct kmem_cache *s, char *buf);
5502 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
5503};
5504
5505#define SLAB_ATTR_RO(_name) \
5506 static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
5507
5508#define SLAB_ATTR(_name) \
5509 static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
5510
5511static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
5512{
5513 return sysfs_emit(buf, "%u\n", s->size);
5514}
5515SLAB_ATTR_RO(slab_size);
5516
5517static ssize_t align_show(struct kmem_cache *s, char *buf)
5518{
5519 return sysfs_emit(buf, "%u\n", s->align);
5520}
5521SLAB_ATTR_RO(align);
5522
5523static ssize_t object_size_show(struct kmem_cache *s, char *buf)
5524{
5525 return sysfs_emit(buf, "%u\n", s->object_size);
5526}
5527SLAB_ATTR_RO(object_size);
5528
5529static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
5530{
5531 return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
5532}
5533SLAB_ATTR_RO(objs_per_slab);
5534
5535static ssize_t order_show(struct kmem_cache *s, char *buf)
5536{
5537 return sysfs_emit(buf, "%u\n", oo_order(s->oo));
5538}
5539SLAB_ATTR_RO(order);
5540
5541static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
5542{
5543 return sysfs_emit(buf, "%lu\n", s->min_partial);
5544}
5545
5546static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
5547 size_t length)
5548{
5549 unsigned long min;
5550 int err;
5551
5552 err = kstrtoul(buf, 10, &min);
5553 if (err)
5554 return err;
5555
5556 s->min_partial = min;
5557 return length;
5558}
5559SLAB_ATTR(min_partial);
5560
5561static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
5562{
5563 unsigned int nr_partial = 0;
5564#ifdef CONFIG_SLUB_CPU_PARTIAL
5565 nr_partial = s->cpu_partial;
5566#endif
5567
5568 return sysfs_emit(buf, "%u\n", nr_partial);
5569}
5570
5571static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
5572 size_t length)
5573{
5574 unsigned int objects;
5575 int err;
5576
5577 err = kstrtouint(buf, 10, &objects);
5578 if (err)
5579 return err;
5580 if (objects && !kmem_cache_has_cpu_partial(s))
5581 return -EINVAL;
5582
5583 slub_set_cpu_partial(s, objects);
5584 flush_all(s);
5585 return length;
5586}
5587SLAB_ATTR(cpu_partial);
5588
5589static ssize_t ctor_show(struct kmem_cache *s, char *buf)
5590{
5591 if (!s->ctor)
5592 return 0;
5593 return sysfs_emit(buf, "%pS\n", s->ctor);
5594}
5595SLAB_ATTR_RO(ctor);
5596
5597static ssize_t aliases_show(struct kmem_cache *s, char *buf)
5598{
5599 return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
5600}
5601SLAB_ATTR_RO(aliases);
5602
5603static ssize_t partial_show(struct kmem_cache *s, char *buf)
5604{
5605 return show_slab_objects(s, buf, SO_PARTIAL);
5606}
5607SLAB_ATTR_RO(partial);
5608
5609static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5610{
5611 return show_slab_objects(s, buf, SO_CPU);
5612}
5613SLAB_ATTR_RO(cpu_slabs);
5614
5615static ssize_t objects_show(struct kmem_cache *s, char *buf)
5616{
5617 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5618}
5619SLAB_ATTR_RO(objects);
5620
5621static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5622{
5623 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5624}
5625SLAB_ATTR_RO(objects_partial);
5626
5627static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5628{
5629 int objects = 0;
5630 int slabs = 0;
5631 int cpu __maybe_unused;
5632 int len = 0;
5633
5634#ifdef CONFIG_SLUB_CPU_PARTIAL
5635 for_each_online_cpu(cpu) {
5636 struct slab *slab;
5637
5638 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5639
5640 if (slab)
5641 slabs += slab->slabs;
5642 }
5643#endif
5644
5645 /* Approximate half-full slabs, see slub_set_cpu_partial() */
5646 objects = (slabs * oo_objects(s->oo)) / 2;
5647 len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
5648
5649#if defined(CONFIG_SLUB_CPU_PARTIAL) && defined(CONFIG_SMP)
5650 for_each_online_cpu(cpu) {
5651 struct slab *slab;
5652
5653 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5654 if (slab) {
5655 slabs = READ_ONCE(slab->slabs);
5656 objects = (slabs * oo_objects(s->oo)) / 2;
5657 len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
5658 cpu, objects, slabs);
5659 }
5660 }
5661#endif
5662 len += sysfs_emit_at(buf, len, "\n");
5663
5664 return len;
5665}
5666SLAB_ATTR_RO(slabs_cpu_partial);
5667
5668static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5669{
5670 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5671}
5672SLAB_ATTR_RO(reclaim_account);
5673
5674static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5675{
5676 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5677}
5678SLAB_ATTR_RO(hwcache_align);
5679
5680#ifdef CONFIG_ZONE_DMA
5681static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5682{
5683 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5684}
5685SLAB_ATTR_RO(cache_dma);
5686#endif
5687
5688#ifdef CONFIG_HARDENED_USERCOPY
5689static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5690{
5691 return sysfs_emit(buf, "%u\n", s->usersize);
5692}
5693SLAB_ATTR_RO(usersize);
5694#endif
5695
5696static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5697{
5698 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5699}
5700SLAB_ATTR_RO(destroy_by_rcu);
5701
5702#ifdef CONFIG_SLUB_DEBUG
5703static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5704{
5705 return show_slab_objects(s, buf, SO_ALL);
5706}
5707SLAB_ATTR_RO(slabs);
5708
5709static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5710{
5711 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5712}
5713SLAB_ATTR_RO(total_objects);
5714
5715static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5716{
5717 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5718}
5719SLAB_ATTR_RO(sanity_checks);
5720
5721static ssize_t trace_show(struct kmem_cache *s, char *buf)
5722{
5723 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5724}
5725SLAB_ATTR_RO(trace);
5726
5727static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5728{
5729 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5730}
5731
5732SLAB_ATTR_RO(red_zone);
5733
5734static ssize_t poison_show(struct kmem_cache *s, char *buf)
5735{
5736 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
5737}
5738
5739SLAB_ATTR_RO(poison);
5740
5741static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5742{
5743 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5744}
5745
5746SLAB_ATTR_RO(store_user);
5747
5748static ssize_t validate_show(struct kmem_cache *s, char *buf)
5749{
5750 return 0;
5751}
5752
5753static ssize_t validate_store(struct kmem_cache *s,
5754 const char *buf, size_t length)
5755{
5756 int ret = -EINVAL;
5757
5758 if (buf[0] == '1' && kmem_cache_debug(s)) {
5759 ret = validate_slab_cache(s);
5760 if (ret >= 0)
5761 ret = length;
5762 }
5763 return ret;
5764}
5765SLAB_ATTR(validate);
5766
5767#endif /* CONFIG_SLUB_DEBUG */
5768
5769#ifdef CONFIG_FAILSLAB
5770static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5771{
5772 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5773}
5774
5775static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5776 size_t length)
5777{
5778 if (s->refcount > 1)
5779 return -EINVAL;
5780
5781 if (buf[0] == '1')
5782 WRITE_ONCE(s->flags, s->flags | SLAB_FAILSLAB);
5783 else
5784 WRITE_ONCE(s->flags, s->flags & ~SLAB_FAILSLAB);
5785
5786 return length;
5787}
5788SLAB_ATTR(failslab);
5789#endif
5790
5791static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5792{
5793 return 0;
5794}
5795
5796static ssize_t shrink_store(struct kmem_cache *s,
5797 const char *buf, size_t length)
5798{
5799 if (buf[0] == '1')
5800 kmem_cache_shrink(s);
5801 else
5802 return -EINVAL;
5803 return length;
5804}
5805SLAB_ATTR(shrink);
5806
5807#ifdef CONFIG_NUMA
5808static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5809{
5810 return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5811}
5812
5813static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5814 const char *buf, size_t length)
5815{
5816 unsigned int ratio;
5817 int err;
5818
5819 err = kstrtouint(buf, 10, &ratio);
5820 if (err)
5821 return err;
5822 if (ratio > 100)
5823 return -ERANGE;
5824
5825 s->remote_node_defrag_ratio = ratio * 10;
5826
5827 return length;
5828}
5829SLAB_ATTR(remote_node_defrag_ratio);
5830#endif
5831
5832#ifdef CONFIG_SLUB_STATS
5833static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5834{
5835 unsigned long sum = 0;
5836 int cpu;
5837 int len = 0;
5838 int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
5839
5840 if (!data)
5841 return -ENOMEM;
5842
5843 for_each_online_cpu(cpu) {
5844 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5845
5846 data[cpu] = x;
5847 sum += x;
5848 }
5849
5850 len += sysfs_emit_at(buf, len, "%lu", sum);
5851
5852#ifdef CONFIG_SMP
5853 for_each_online_cpu(cpu) {
5854 if (data[cpu])
5855 len += sysfs_emit_at(buf, len, " C%d=%u",
5856 cpu, data[cpu]);
5857 }
5858#endif
5859 kfree(data);
5860 len += sysfs_emit_at(buf, len, "\n");
5861
5862 return len;
5863}
5864
5865static void clear_stat(struct kmem_cache *s, enum stat_item si)
5866{
5867 int cpu;
5868
5869 for_each_online_cpu(cpu)
5870 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5871}
5872
5873#define STAT_ATTR(si, text) \
5874static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5875{ \
5876 return show_stat(s, buf, si); \
5877} \
5878static ssize_t text##_store(struct kmem_cache *s, \
5879 const char *buf, size_t length) \
5880{ \
5881 if (buf[0] != '0') \
5882 return -EINVAL; \
5883 clear_stat(s, si); \
5884 return length; \
5885} \
5886SLAB_ATTR(text); \
5887
5888STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5889STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5890STAT_ATTR(FREE_FASTPATH, free_fastpath);
5891STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5892STAT_ATTR(FREE_FROZEN, free_frozen);
5893STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5894STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5895STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5896STAT_ATTR(ALLOC_SLAB, alloc_slab);
5897STAT_ATTR(ALLOC_REFILL, alloc_refill);
5898STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5899STAT_ATTR(FREE_SLAB, free_slab);
5900STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5901STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5902STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5903STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5904STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5905STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5906STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5907STAT_ATTR(ORDER_FALLBACK, order_fallback);
5908STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5909STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5910STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5911STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5912STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5913STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5914#endif /* CONFIG_SLUB_STATS */
5915
5916#ifdef CONFIG_KFENCE
5917static ssize_t skip_kfence_show(struct kmem_cache *s, char *buf)
5918{
5919 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_SKIP_KFENCE));
5920}
5921
5922static ssize_t skip_kfence_store(struct kmem_cache *s,
5923 const char *buf, size_t length)
5924{
5925 int ret = length;
5926
5927 if (buf[0] == '0')
5928 s->flags &= ~SLAB_SKIP_KFENCE;
5929 else if (buf[0] == '1')
5930 s->flags |= SLAB_SKIP_KFENCE;
5931 else
5932 ret = -EINVAL;
5933
5934 return ret;
5935}
5936SLAB_ATTR(skip_kfence);
5937#endif
5938
5939static struct attribute *slab_attrs[] = {
5940 &slab_size_attr.attr,
5941 &object_size_attr.attr,
5942 &objs_per_slab_attr.attr,
5943 &order_attr.attr,
5944 &min_partial_attr.attr,
5945 &cpu_partial_attr.attr,
5946 &objects_attr.attr,
5947 &objects_partial_attr.attr,
5948 &partial_attr.attr,
5949 &cpu_slabs_attr.attr,
5950 &ctor_attr.attr,
5951 &aliases_attr.attr,
5952 &align_attr.attr,
5953 &hwcache_align_attr.attr,
5954 &reclaim_account_attr.attr,
5955 &destroy_by_rcu_attr.attr,
5956 &shrink_attr.attr,
5957 &slabs_cpu_partial_attr.attr,
5958#ifdef CONFIG_SLUB_DEBUG
5959 &total_objects_attr.attr,
5960 &slabs_attr.attr,
5961 &sanity_checks_attr.attr,
5962 &trace_attr.attr,
5963 &red_zone_attr.attr,
5964 &poison_attr.attr,
5965 &store_user_attr.attr,
5966 &validate_attr.attr,
5967#endif
5968#ifdef CONFIG_ZONE_DMA
5969 &cache_dma_attr.attr,
5970#endif
5971#ifdef CONFIG_NUMA
5972 &remote_node_defrag_ratio_attr.attr,
5973#endif
5974#ifdef CONFIG_SLUB_STATS
5975 &alloc_fastpath_attr.attr,
5976 &alloc_slowpath_attr.attr,
5977 &free_fastpath_attr.attr,
5978 &free_slowpath_attr.attr,
5979 &free_frozen_attr.attr,
5980 &free_add_partial_attr.attr,
5981 &free_remove_partial_attr.attr,
5982 &alloc_from_partial_attr.attr,
5983 &alloc_slab_attr.attr,
5984 &alloc_refill_attr.attr,
5985 &alloc_node_mismatch_attr.attr,
5986 &free_slab_attr.attr,
5987 &cpuslab_flush_attr.attr,
5988 &deactivate_full_attr.attr,
5989 &deactivate_empty_attr.attr,
5990 &deactivate_to_head_attr.attr,
5991 &deactivate_to_tail_attr.attr,
5992 &deactivate_remote_frees_attr.attr,
5993 &deactivate_bypass_attr.attr,
5994 &order_fallback_attr.attr,
5995 &cmpxchg_double_fail_attr.attr,
5996 &cmpxchg_double_cpu_fail_attr.attr,
5997 &cpu_partial_alloc_attr.attr,
5998 &cpu_partial_free_attr.attr,
5999 &cpu_partial_node_attr.attr,
6000 &cpu_partial_drain_attr.attr,
6001#endif
6002#ifdef CONFIG_FAILSLAB
6003 &failslab_attr.attr,
6004#endif
6005#ifdef CONFIG_HARDENED_USERCOPY
6006 &usersize_attr.attr,
6007#endif
6008#ifdef CONFIG_KFENCE
6009 &skip_kfence_attr.attr,
6010#endif
6011
6012 NULL
6013};
6014
6015static const struct attribute_group slab_attr_group = {
6016 .attrs = slab_attrs,
6017};
6018
6019static ssize_t slab_attr_show(struct kobject *kobj,
6020 struct attribute *attr,
6021 char *buf)
6022{
6023 struct slab_attribute *attribute;
6024 struct kmem_cache *s;
6025
6026 attribute = to_slab_attr(attr);
6027 s = to_slab(kobj);
6028
6029 if (!attribute->show)
6030 return -EIO;
6031
6032 return attribute->show(s, buf);
6033}
6034
6035static ssize_t slab_attr_store(struct kobject *kobj,
6036 struct attribute *attr,
6037 const char *buf, size_t len)
6038{
6039 struct slab_attribute *attribute;
6040 struct kmem_cache *s;
6041
6042 attribute = to_slab_attr(attr);
6043 s = to_slab(kobj);
6044
6045 if (!attribute->store)
6046 return -EIO;
6047
6048 return attribute->store(s, buf, len);
6049}
6050
6051static void kmem_cache_release(struct kobject *k)
6052{
6053 slab_kmem_cache_release(to_slab(k));
6054}
6055
6056static const struct sysfs_ops slab_sysfs_ops = {
6057 .show = slab_attr_show,
6058 .store = slab_attr_store,
6059};
6060
6061static struct kobj_type slab_ktype = {
6062 .sysfs_ops = &slab_sysfs_ops,
6063 .release = kmem_cache_release,
6064};
6065
6066static struct kset *slab_kset;
6067
6068static inline struct kset *cache_kset(struct kmem_cache *s)
6069{
6070 return slab_kset;
6071}
6072
6073#define ID_STR_LENGTH 32
6074
6075/* Create a unique string id for a slab cache:
6076 *
6077 * Format :[flags-]size
6078 */
6079static char *create_unique_id(struct kmem_cache *s)
6080{
6081 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
6082 char *p = name;
6083
6084 if (!name)
6085 return ERR_PTR(-ENOMEM);
6086
6087 *p++ = ':';
6088 /*
6089 * First flags affecting slabcache operations. We will only
6090 * get here for aliasable slabs so we do not need to support
6091 * too many flags. The flags here must cover all flags that
6092 * are matched during merging to guarantee that the id is
6093 * unique.
6094 */
6095 if (s->flags & SLAB_CACHE_DMA)
6096 *p++ = 'd';
6097 if (s->flags & SLAB_CACHE_DMA32)
6098 *p++ = 'D';
6099 if (s->flags & SLAB_RECLAIM_ACCOUNT)
6100 *p++ = 'a';
6101 if (s->flags & SLAB_CONSISTENCY_CHECKS)
6102 *p++ = 'F';
6103 if (s->flags & SLAB_ACCOUNT)
6104 *p++ = 'A';
6105 if (p != name + 1)
6106 *p++ = '-';
6107 p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
6108
6109 if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
6110 kfree(name);
6111 return ERR_PTR(-EINVAL);
6112 }
6113 kmsan_unpoison_memory(name, p - name);
6114 return name;
6115}
6116
6117static int sysfs_slab_add(struct kmem_cache *s)
6118{
6119 int err;
6120 const char *name;
6121 struct kset *kset = cache_kset(s);
6122 int unmergeable = slab_unmergeable(s);
6123
6124 if (!unmergeable && disable_higher_order_debug &&
6125 (slub_debug & DEBUG_METADATA_FLAGS))
6126 unmergeable = 1;
6127
6128 if (unmergeable) {
6129 /*
6130 * Slabcache can never be merged so we can use the name proper.
6131 * This is typically the case for debug situations. In that
6132 * case we can catch duplicate names easily.
6133 */
6134 sysfs_remove_link(&slab_kset->kobj, s->name);
6135 name = s->name;
6136 } else {
6137 /*
6138 * Create a unique name for the slab as a target
6139 * for the symlinks.
6140 */
6141 name = create_unique_id(s);
6142 if (IS_ERR(name))
6143 return PTR_ERR(name);
6144 }
6145
6146 s->kobj.kset = kset;
6147 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
6148 if (err)
6149 goto out;
6150
6151 err = sysfs_create_group(&s->kobj, &slab_attr_group);
6152 if (err)
6153 goto out_del_kobj;
6154
6155 if (!unmergeable) {
6156 /* Setup first alias */
6157 sysfs_slab_alias(s, s->name);
6158 }
6159out:
6160 if (!unmergeable)
6161 kfree(name);
6162 return err;
6163out_del_kobj:
6164 kobject_del(&s->kobj);
6165 goto out;
6166}
6167
6168void sysfs_slab_unlink(struct kmem_cache *s)
6169{
6170 if (slab_state >= FULL)
6171 kobject_del(&s->kobj);
6172}
6173
6174void sysfs_slab_release(struct kmem_cache *s)
6175{
6176 if (slab_state >= FULL)
6177 kobject_put(&s->kobj);
6178}
6179
6180/*
6181 * Need to buffer aliases during bootup until sysfs becomes
6182 * available lest we lose that information.
6183 */
6184struct saved_alias {
6185 struct kmem_cache *s;
6186 const char *name;
6187 struct saved_alias *next;
6188};
6189
6190static struct saved_alias *alias_list;
6191
6192static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
6193{
6194 struct saved_alias *al;
6195
6196 if (slab_state == FULL) {
6197 /*
6198 * If we have a leftover link then remove it.
6199 */
6200 sysfs_remove_link(&slab_kset->kobj, name);
6201 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
6202 }
6203
6204 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
6205 if (!al)
6206 return -ENOMEM;
6207
6208 al->s = s;
6209 al->name = name;
6210 al->next = alias_list;
6211 alias_list = al;
6212 kmsan_unpoison_memory(al, sizeof(*al));
6213 return 0;
6214}
6215
6216static int __init slab_sysfs_init(void)
6217{
6218 struct kmem_cache *s;
6219 int err;
6220
6221 mutex_lock(&slab_mutex);
6222
6223 slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
6224 if (!slab_kset) {
6225 mutex_unlock(&slab_mutex);
6226 pr_err("Cannot register slab subsystem.\n");
6227 return -ENOSYS;
6228 }
6229
6230 slab_state = FULL;
6231
6232 list_for_each_entry(s, &slab_caches, list) {
6233 err = sysfs_slab_add(s);
6234 if (err)
6235 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
6236 s->name);
6237 }
6238
6239 while (alias_list) {
6240 struct saved_alias *al = alias_list;
6241
6242 alias_list = alias_list->next;
6243 err = sysfs_slab_alias(al->s, al->name);
6244 if (err)
6245 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
6246 al->name);
6247 kfree(al);
6248 }
6249
6250 mutex_unlock(&slab_mutex);
6251 return 0;
6252}
6253late_initcall(slab_sysfs_init);
6254#endif /* SLAB_SUPPORTS_SYSFS */
6255
6256#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
6257static int slab_debugfs_show(struct seq_file *seq, void *v)
6258{
6259 struct loc_track *t = seq->private;
6260 struct location *l;
6261 unsigned long idx;
6262
6263 idx = (unsigned long) t->idx;
6264 if (idx < t->count) {
6265 l = &t->loc[idx];
6266
6267 seq_printf(seq, "%7ld ", l->count);
6268
6269 if (l->addr)
6270 seq_printf(seq, "%pS", (void *)l->addr);
6271 else
6272 seq_puts(seq, "<not-available>");
6273
6274 if (l->waste)
6275 seq_printf(seq, " waste=%lu/%lu",
6276 l->count * l->waste, l->waste);
6277
6278 if (l->sum_time != l->min_time) {
6279 seq_printf(seq, " age=%ld/%llu/%ld",
6280 l->min_time, div_u64(l->sum_time, l->count),
6281 l->max_time);
6282 } else
6283 seq_printf(seq, " age=%ld", l->min_time);
6284
6285 if (l->min_pid != l->max_pid)
6286 seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
6287 else
6288 seq_printf(seq, " pid=%ld",
6289 l->min_pid);
6290
6291 if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
6292 seq_printf(seq, " cpus=%*pbl",
6293 cpumask_pr_args(to_cpumask(l->cpus)));
6294
6295 if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
6296 seq_printf(seq, " nodes=%*pbl",
6297 nodemask_pr_args(&l->nodes));
6298
6299#ifdef CONFIG_STACKDEPOT
6300 {
6301 depot_stack_handle_t handle;
6302 unsigned long *entries;
6303 unsigned int nr_entries, j;
6304
6305 handle = READ_ONCE(l->handle);
6306 if (handle) {
6307 nr_entries = stack_depot_fetch(handle, &entries);
6308 seq_puts(seq, "\n");
6309 for (j = 0; j < nr_entries; j++)
6310 seq_printf(seq, " %pS\n", (void *)entries[j]);
6311 }
6312 }
6313#endif
6314 seq_puts(seq, "\n");
6315 }
6316
6317 if (!idx && !t->count)
6318 seq_puts(seq, "No data\n");
6319
6320 return 0;
6321}
6322
6323static void slab_debugfs_stop(struct seq_file *seq, void *v)
6324{
6325}
6326
6327static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
6328{
6329 struct loc_track *t = seq->private;
6330
6331 t->idx = ++(*ppos);
6332 if (*ppos <= t->count)
6333 return ppos;
6334
6335 return NULL;
6336}
6337
6338static int cmp_loc_by_count(const void *a, const void *b, const void *data)
6339{
6340 struct location *loc1 = (struct location *)a;
6341 struct location *loc2 = (struct location *)b;
6342
6343 if (loc1->count > loc2->count)
6344 return -1;
6345 else
6346 return 1;
6347}
6348
6349static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
6350{
6351 struct loc_track *t = seq->private;
6352
6353 t->idx = *ppos;
6354 return ppos;
6355}
6356
6357static const struct seq_operations slab_debugfs_sops = {
6358 .start = slab_debugfs_start,
6359 .next = slab_debugfs_next,
6360 .stop = slab_debugfs_stop,
6361 .show = slab_debugfs_show,
6362};
6363
6364static int slab_debug_trace_open(struct inode *inode, struct file *filep)
6365{
6366
6367 struct kmem_cache_node *n;
6368 enum track_item alloc;
6369 int node;
6370 struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
6371 sizeof(struct loc_track));
6372 struct kmem_cache *s = file_inode(filep)->i_private;
6373 unsigned long *obj_map;
6374
6375 if (!t)
6376 return -ENOMEM;
6377
6378 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
6379 if (!obj_map) {
6380 seq_release_private(inode, filep);
6381 return -ENOMEM;
6382 }
6383
6384 if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
6385 alloc = TRACK_ALLOC;
6386 else
6387 alloc = TRACK_FREE;
6388
6389 if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
6390 bitmap_free(obj_map);
6391 seq_release_private(inode, filep);
6392 return -ENOMEM;
6393 }
6394
6395 for_each_kmem_cache_node(s, node, n) {
6396 unsigned long flags;
6397 struct slab *slab;
6398
6399 if (!atomic_long_read(&n->nr_slabs))
6400 continue;
6401
6402 spin_lock_irqsave(&n->list_lock, flags);
6403 list_for_each_entry(slab, &n->partial, slab_list)
6404 process_slab(t, s, slab, alloc, obj_map);
6405 list_for_each_entry(slab, &n->full, slab_list)
6406 process_slab(t, s, slab, alloc, obj_map);
6407 spin_unlock_irqrestore(&n->list_lock, flags);
6408 }
6409
6410 /* Sort locations by count */
6411 sort_r(t->loc, t->count, sizeof(struct location),
6412 cmp_loc_by_count, NULL, NULL);
6413
6414 bitmap_free(obj_map);
6415 return 0;
6416}
6417
6418static int slab_debug_trace_release(struct inode *inode, struct file *file)
6419{
6420 struct seq_file *seq = file->private_data;
6421 struct loc_track *t = seq->private;
6422
6423 free_loc_track(t);
6424 return seq_release_private(inode, file);
6425}
6426
6427static const struct file_operations slab_debugfs_fops = {
6428 .open = slab_debug_trace_open,
6429 .read = seq_read,
6430 .llseek = seq_lseek,
6431 .release = slab_debug_trace_release,
6432};
6433
6434static void debugfs_slab_add(struct kmem_cache *s)
6435{
6436 struct dentry *slab_cache_dir;
6437
6438 if (unlikely(!slab_debugfs_root))
6439 return;
6440
6441 slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
6442
6443 debugfs_create_file("alloc_traces", 0400,
6444 slab_cache_dir, s, &slab_debugfs_fops);
6445
6446 debugfs_create_file("free_traces", 0400,
6447 slab_cache_dir, s, &slab_debugfs_fops);
6448}
6449
6450void debugfs_slab_release(struct kmem_cache *s)
6451{
6452 debugfs_remove_recursive(debugfs_lookup(s->name, slab_debugfs_root));
6453}
6454
6455static int __init slab_debugfs_init(void)
6456{
6457 struct kmem_cache *s;
6458
6459 slab_debugfs_root = debugfs_create_dir("slab", NULL);
6460
6461 list_for_each_entry(s, &slab_caches, list)
6462 if (s->flags & SLAB_STORE_USER)
6463 debugfs_slab_add(s);
6464
6465 return 0;
6466
6467}
6468__initcall(slab_debugfs_init);
6469#endif
6470/*
6471 * The /proc/slabinfo ABI
6472 */
6473#ifdef CONFIG_SLUB_DEBUG
6474void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
6475{
6476 unsigned long nr_slabs = 0;
6477 unsigned long nr_objs = 0;
6478 unsigned long nr_free = 0;
6479 int node;
6480 struct kmem_cache_node *n;
6481
6482 for_each_kmem_cache_node(s, node, n) {
6483 nr_slabs += node_nr_slabs(n);
6484 nr_objs += node_nr_objs(n);
6485 nr_free += count_partial(n, count_free);
6486 }
6487
6488 sinfo->active_objs = nr_objs - nr_free;
6489 sinfo->num_objs = nr_objs;
6490 sinfo->active_slabs = nr_slabs;
6491 sinfo->num_slabs = nr_slabs;
6492 sinfo->objects_per_slab = oo_objects(s->oo);
6493 sinfo->cache_order = oo_order(s->oo);
6494}
6495
6496void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
6497{
6498}
6499
6500ssize_t slabinfo_write(struct file *file, const char __user *buffer,
6501 size_t count, loff_t *ppos)
6502{
6503 return -EIO;
6504}
6505#endif /* CONFIG_SLUB_DEBUG */
1/*
2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
4 *
5 * The allocator synchronizes using per slab locks or atomic operatios
6 * and only uses a centralized lock to manage a pool of partial slabs.
7 *
8 * (C) 2007 SGI, Christoph Lameter
9 * (C) 2011 Linux Foundation, Christoph Lameter
10 */
11
12#include <linux/mm.h>
13#include <linux/swap.h> /* struct reclaim_state */
14#include <linux/module.h>
15#include <linux/bit_spinlock.h>
16#include <linux/interrupt.h>
17#include <linux/bitops.h>
18#include <linux/slab.h>
19#include <linux/proc_fs.h>
20#include <linux/seq_file.h>
21#include <linux/kmemcheck.h>
22#include <linux/cpu.h>
23#include <linux/cpuset.h>
24#include <linux/mempolicy.h>
25#include <linux/ctype.h>
26#include <linux/debugobjects.h>
27#include <linux/kallsyms.h>
28#include <linux/memory.h>
29#include <linux/math64.h>
30#include <linux/fault-inject.h>
31#include <linux/stacktrace.h>
32#include <linux/prefetch.h>
33
34#include <trace/events/kmem.h>
35
36/*
37 * Lock order:
38 * 1. slub_lock (Global Semaphore)
39 * 2. node->list_lock
40 * 3. slab_lock(page) (Only on some arches and for debugging)
41 *
42 * slub_lock
43 *
44 * The role of the slub_lock is to protect the list of all the slabs
45 * and to synchronize major metadata changes to slab cache structures.
46 *
47 * The slab_lock is only used for debugging and on arches that do not
48 * have the ability to do a cmpxchg_double. It only protects the second
49 * double word in the page struct. Meaning
50 * A. page->freelist -> List of object free in a page
51 * B. page->counters -> Counters of objects
52 * C. page->frozen -> frozen state
53 *
54 * If a slab is frozen then it is exempt from list management. It is not
55 * on any list. The processor that froze the slab is the one who can
56 * perform list operations on the page. Other processors may put objects
57 * onto the freelist but the processor that froze the slab is the only
58 * one that can retrieve the objects from the page's freelist.
59 *
60 * The list_lock protects the partial and full list on each node and
61 * the partial slab counter. If taken then no new slabs may be added or
62 * removed from the lists nor make the number of partial slabs be modified.
63 * (Note that the total number of slabs is an atomic value that may be
64 * modified without taking the list lock).
65 *
66 * The list_lock is a centralized lock and thus we avoid taking it as
67 * much as possible. As long as SLUB does not have to handle partial
68 * slabs, operations can continue without any centralized lock. F.e.
69 * allocating a long series of objects that fill up slabs does not require
70 * the list lock.
71 * Interrupts are disabled during allocation and deallocation in order to
72 * make the slab allocator safe to use in the context of an irq. In addition
73 * interrupts are disabled to ensure that the processor does not change
74 * while handling per_cpu slabs, due to kernel preemption.
75 *
76 * SLUB assigns one slab for allocation to each processor.
77 * Allocations only occur from these slabs called cpu slabs.
78 *
79 * Slabs with free elements are kept on a partial list and during regular
80 * operations no list for full slabs is used. If an object in a full slab is
81 * freed then the slab will show up again on the partial lists.
82 * We track full slabs for debugging purposes though because otherwise we
83 * cannot scan all objects.
84 *
85 * Slabs are freed when they become empty. Teardown and setup is
86 * minimal so we rely on the page allocators per cpu caches for
87 * fast frees and allocs.
88 *
89 * Overloading of page flags that are otherwise used for LRU management.
90 *
91 * PageActive The slab is frozen and exempt from list processing.
92 * This means that the slab is dedicated to a purpose
93 * such as satisfying allocations for a specific
94 * processor. Objects may be freed in the slab while
95 * it is frozen but slab_free will then skip the usual
96 * list operations. It is up to the processor holding
97 * the slab to integrate the slab into the slab lists
98 * when the slab is no longer needed.
99 *
100 * One use of this flag is to mark slabs that are
101 * used for allocations. Then such a slab becomes a cpu
102 * slab. The cpu slab may be equipped with an additional
103 * freelist that allows lockless access to
104 * free objects in addition to the regular freelist
105 * that requires the slab lock.
106 *
107 * PageError Slab requires special handling due to debug
108 * options set. This moves slab handling out of
109 * the fast path and disables lockless freelists.
110 */
111
112#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
113 SLAB_TRACE | SLAB_DEBUG_FREE)
114
115static inline int kmem_cache_debug(struct kmem_cache *s)
116{
117#ifdef CONFIG_SLUB_DEBUG
118 return unlikely(s->flags & SLAB_DEBUG_FLAGS);
119#else
120 return 0;
121#endif
122}
123
124/*
125 * Issues still to be resolved:
126 *
127 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
128 *
129 * - Variable sizing of the per node arrays
130 */
131
132/* Enable to test recovery from slab corruption on boot */
133#undef SLUB_RESILIENCY_TEST
134
135/* Enable to log cmpxchg failures */
136#undef SLUB_DEBUG_CMPXCHG
137
138/*
139 * Mininum number of partial slabs. These will be left on the partial
140 * lists even if they are empty. kmem_cache_shrink may reclaim them.
141 */
142#define MIN_PARTIAL 5
143
144/*
145 * Maximum number of desirable partial slabs.
146 * The existence of more partial slabs makes kmem_cache_shrink
147 * sort the partial list by the number of objects in the.
148 */
149#define MAX_PARTIAL 10
150
151#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
152 SLAB_POISON | SLAB_STORE_USER)
153
154/*
155 * Debugging flags that require metadata to be stored in the slab. These get
156 * disabled when slub_debug=O is used and a cache's min order increases with
157 * metadata.
158 */
159#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
160
161/*
162 * Set of flags that will prevent slab merging
163 */
164#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
165 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
166 SLAB_FAILSLAB)
167
168#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
169 SLAB_CACHE_DMA | SLAB_NOTRACK)
170
171#define OO_SHIFT 16
172#define OO_MASK ((1 << OO_SHIFT) - 1)
173#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
174
175/* Internal SLUB flags */
176#define __OBJECT_POISON 0x80000000UL /* Poison object */
177#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
178
179static int kmem_size = sizeof(struct kmem_cache);
180
181#ifdef CONFIG_SMP
182static struct notifier_block slab_notifier;
183#endif
184
185static enum {
186 DOWN, /* No slab functionality available */
187 PARTIAL, /* Kmem_cache_node works */
188 UP, /* Everything works but does not show up in sysfs */
189 SYSFS /* Sysfs up */
190} slab_state = DOWN;
191
192/* A list of all slab caches on the system */
193static DECLARE_RWSEM(slub_lock);
194static LIST_HEAD(slab_caches);
195
196/*
197 * Tracking user of a slab.
198 */
199#define TRACK_ADDRS_COUNT 16
200struct track {
201 unsigned long addr; /* Called from address */
202#ifdef CONFIG_STACKTRACE
203 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
204#endif
205 int cpu; /* Was running on cpu */
206 int pid; /* Pid context */
207 unsigned long when; /* When did the operation occur */
208};
209
210enum track_item { TRACK_ALLOC, TRACK_FREE };
211
212#ifdef CONFIG_SYSFS
213static int sysfs_slab_add(struct kmem_cache *);
214static int sysfs_slab_alias(struct kmem_cache *, const char *);
215static void sysfs_slab_remove(struct kmem_cache *);
216
217#else
218static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
219static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
220 { return 0; }
221static inline void sysfs_slab_remove(struct kmem_cache *s)
222{
223 kfree(s->name);
224 kfree(s);
225}
226
227#endif
228
229static inline void stat(const struct kmem_cache *s, enum stat_item si)
230{
231#ifdef CONFIG_SLUB_STATS
232 __this_cpu_inc(s->cpu_slab->stat[si]);
233#endif
234}
235
236/********************************************************************
237 * Core slab cache functions
238 *******************************************************************/
239
240int slab_is_available(void)
241{
242 return slab_state >= UP;
243}
244
245static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
246{
247 return s->node[node];
248}
249
250/* Verify that a pointer has an address that is valid within a slab page */
251static inline int check_valid_pointer(struct kmem_cache *s,
252 struct page *page, const void *object)
253{
254 void *base;
255
256 if (!object)
257 return 1;
258
259 base = page_address(page);
260 if (object < base || object >= base + page->objects * s->size ||
261 (object - base) % s->size) {
262 return 0;
263 }
264
265 return 1;
266}
267
268static inline void *get_freepointer(struct kmem_cache *s, void *object)
269{
270 return *(void **)(object + s->offset);
271}
272
273static void prefetch_freepointer(const struct kmem_cache *s, void *object)
274{
275 prefetch(object + s->offset);
276}
277
278static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
279{
280 void *p;
281
282#ifdef CONFIG_DEBUG_PAGEALLOC
283 probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
284#else
285 p = get_freepointer(s, object);
286#endif
287 return p;
288}
289
290static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
291{
292 *(void **)(object + s->offset) = fp;
293}
294
295/* Loop over all objects in a slab */
296#define for_each_object(__p, __s, __addr, __objects) \
297 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
298 __p += (__s)->size)
299
300/* Determine object index from a given position */
301static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
302{
303 return (p - addr) / s->size;
304}
305
306static inline size_t slab_ksize(const struct kmem_cache *s)
307{
308#ifdef CONFIG_SLUB_DEBUG
309 /*
310 * Debugging requires use of the padding between object
311 * and whatever may come after it.
312 */
313 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
314 return s->objsize;
315
316#endif
317 /*
318 * If we have the need to store the freelist pointer
319 * back there or track user information then we can
320 * only use the space before that information.
321 */
322 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
323 return s->inuse;
324 /*
325 * Else we can use all the padding etc for the allocation
326 */
327 return s->size;
328}
329
330static inline int order_objects(int order, unsigned long size, int reserved)
331{
332 return ((PAGE_SIZE << order) - reserved) / size;
333}
334
335static inline struct kmem_cache_order_objects oo_make(int order,
336 unsigned long size, int reserved)
337{
338 struct kmem_cache_order_objects x = {
339 (order << OO_SHIFT) + order_objects(order, size, reserved)
340 };
341
342 return x;
343}
344
345static inline int oo_order(struct kmem_cache_order_objects x)
346{
347 return x.x >> OO_SHIFT;
348}
349
350static inline int oo_objects(struct kmem_cache_order_objects x)
351{
352 return x.x & OO_MASK;
353}
354
355/*
356 * Per slab locking using the pagelock
357 */
358static __always_inline void slab_lock(struct page *page)
359{
360 bit_spin_lock(PG_locked, &page->flags);
361}
362
363static __always_inline void slab_unlock(struct page *page)
364{
365 __bit_spin_unlock(PG_locked, &page->flags);
366}
367
368/* Interrupts must be disabled (for the fallback code to work right) */
369static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
370 void *freelist_old, unsigned long counters_old,
371 void *freelist_new, unsigned long counters_new,
372 const char *n)
373{
374 VM_BUG_ON(!irqs_disabled());
375#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
376 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
377 if (s->flags & __CMPXCHG_DOUBLE) {
378 if (cmpxchg_double(&page->freelist, &page->counters,
379 freelist_old, counters_old,
380 freelist_new, counters_new))
381 return 1;
382 } else
383#endif
384 {
385 slab_lock(page);
386 if (page->freelist == freelist_old && page->counters == counters_old) {
387 page->freelist = freelist_new;
388 page->counters = counters_new;
389 slab_unlock(page);
390 return 1;
391 }
392 slab_unlock(page);
393 }
394
395 cpu_relax();
396 stat(s, CMPXCHG_DOUBLE_FAIL);
397
398#ifdef SLUB_DEBUG_CMPXCHG
399 printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
400#endif
401
402 return 0;
403}
404
405static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
406 void *freelist_old, unsigned long counters_old,
407 void *freelist_new, unsigned long counters_new,
408 const char *n)
409{
410#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
411 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
412 if (s->flags & __CMPXCHG_DOUBLE) {
413 if (cmpxchg_double(&page->freelist, &page->counters,
414 freelist_old, counters_old,
415 freelist_new, counters_new))
416 return 1;
417 } else
418#endif
419 {
420 unsigned long flags;
421
422 local_irq_save(flags);
423 slab_lock(page);
424 if (page->freelist == freelist_old && page->counters == counters_old) {
425 page->freelist = freelist_new;
426 page->counters = counters_new;
427 slab_unlock(page);
428 local_irq_restore(flags);
429 return 1;
430 }
431 slab_unlock(page);
432 local_irq_restore(flags);
433 }
434
435 cpu_relax();
436 stat(s, CMPXCHG_DOUBLE_FAIL);
437
438#ifdef SLUB_DEBUG_CMPXCHG
439 printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
440#endif
441
442 return 0;
443}
444
445#ifdef CONFIG_SLUB_DEBUG
446/*
447 * Determine a map of object in use on a page.
448 *
449 * Node listlock must be held to guarantee that the page does
450 * not vanish from under us.
451 */
452static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
453{
454 void *p;
455 void *addr = page_address(page);
456
457 for (p = page->freelist; p; p = get_freepointer(s, p))
458 set_bit(slab_index(p, s, addr), map);
459}
460
461/*
462 * Debug settings:
463 */
464#ifdef CONFIG_SLUB_DEBUG_ON
465static int slub_debug = DEBUG_DEFAULT_FLAGS;
466#else
467static int slub_debug;
468#endif
469
470static char *slub_debug_slabs;
471static int disable_higher_order_debug;
472
473/*
474 * Object debugging
475 */
476static void print_section(char *text, u8 *addr, unsigned int length)
477{
478 print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
479 length, 1);
480}
481
482static struct track *get_track(struct kmem_cache *s, void *object,
483 enum track_item alloc)
484{
485 struct track *p;
486
487 if (s->offset)
488 p = object + s->offset + sizeof(void *);
489 else
490 p = object + s->inuse;
491
492 return p + alloc;
493}
494
495static void set_track(struct kmem_cache *s, void *object,
496 enum track_item alloc, unsigned long addr)
497{
498 struct track *p = get_track(s, object, alloc);
499
500 if (addr) {
501#ifdef CONFIG_STACKTRACE
502 struct stack_trace trace;
503 int i;
504
505 trace.nr_entries = 0;
506 trace.max_entries = TRACK_ADDRS_COUNT;
507 trace.entries = p->addrs;
508 trace.skip = 3;
509 save_stack_trace(&trace);
510
511 /* See rant in lockdep.c */
512 if (trace.nr_entries != 0 &&
513 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
514 trace.nr_entries--;
515
516 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
517 p->addrs[i] = 0;
518#endif
519 p->addr = addr;
520 p->cpu = smp_processor_id();
521 p->pid = current->pid;
522 p->when = jiffies;
523 } else
524 memset(p, 0, sizeof(struct track));
525}
526
527static void init_tracking(struct kmem_cache *s, void *object)
528{
529 if (!(s->flags & SLAB_STORE_USER))
530 return;
531
532 set_track(s, object, TRACK_FREE, 0UL);
533 set_track(s, object, TRACK_ALLOC, 0UL);
534}
535
536static void print_track(const char *s, struct track *t)
537{
538 if (!t->addr)
539 return;
540
541 printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
542 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
543#ifdef CONFIG_STACKTRACE
544 {
545 int i;
546 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
547 if (t->addrs[i])
548 printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
549 else
550 break;
551 }
552#endif
553}
554
555static void print_tracking(struct kmem_cache *s, void *object)
556{
557 if (!(s->flags & SLAB_STORE_USER))
558 return;
559
560 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
561 print_track("Freed", get_track(s, object, TRACK_FREE));
562}
563
564static void print_page_info(struct page *page)
565{
566 printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
567 page, page->objects, page->inuse, page->freelist, page->flags);
568
569}
570
571static void slab_bug(struct kmem_cache *s, char *fmt, ...)
572{
573 va_list args;
574 char buf[100];
575
576 va_start(args, fmt);
577 vsnprintf(buf, sizeof(buf), fmt, args);
578 va_end(args);
579 printk(KERN_ERR "========================================"
580 "=====================================\n");
581 printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
582 printk(KERN_ERR "----------------------------------------"
583 "-------------------------------------\n\n");
584}
585
586static void slab_fix(struct kmem_cache *s, char *fmt, ...)
587{
588 va_list args;
589 char buf[100];
590
591 va_start(args, fmt);
592 vsnprintf(buf, sizeof(buf), fmt, args);
593 va_end(args);
594 printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
595}
596
597static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
598{
599 unsigned int off; /* Offset of last byte */
600 u8 *addr = page_address(page);
601
602 print_tracking(s, p);
603
604 print_page_info(page);
605
606 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
607 p, p - addr, get_freepointer(s, p));
608
609 if (p > addr + 16)
610 print_section("Bytes b4 ", p - 16, 16);
611
612 print_section("Object ", p, min_t(unsigned long, s->objsize,
613 PAGE_SIZE));
614 if (s->flags & SLAB_RED_ZONE)
615 print_section("Redzone ", p + s->objsize,
616 s->inuse - s->objsize);
617
618 if (s->offset)
619 off = s->offset + sizeof(void *);
620 else
621 off = s->inuse;
622
623 if (s->flags & SLAB_STORE_USER)
624 off += 2 * sizeof(struct track);
625
626 if (off != s->size)
627 /* Beginning of the filler is the free pointer */
628 print_section("Padding ", p + off, s->size - off);
629
630 dump_stack();
631}
632
633static void object_err(struct kmem_cache *s, struct page *page,
634 u8 *object, char *reason)
635{
636 slab_bug(s, "%s", reason);
637 print_trailer(s, page, object);
638}
639
640static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
641{
642 va_list args;
643 char buf[100];
644
645 va_start(args, fmt);
646 vsnprintf(buf, sizeof(buf), fmt, args);
647 va_end(args);
648 slab_bug(s, "%s", buf);
649 print_page_info(page);
650 dump_stack();
651}
652
653static void init_object(struct kmem_cache *s, void *object, u8 val)
654{
655 u8 *p = object;
656
657 if (s->flags & __OBJECT_POISON) {
658 memset(p, POISON_FREE, s->objsize - 1);
659 p[s->objsize - 1] = POISON_END;
660 }
661
662 if (s->flags & SLAB_RED_ZONE)
663 memset(p + s->objsize, val, s->inuse - s->objsize);
664}
665
666static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
667 void *from, void *to)
668{
669 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
670 memset(from, data, to - from);
671}
672
673static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
674 u8 *object, char *what,
675 u8 *start, unsigned int value, unsigned int bytes)
676{
677 u8 *fault;
678 u8 *end;
679
680 fault = memchr_inv(start, value, bytes);
681 if (!fault)
682 return 1;
683
684 end = start + bytes;
685 while (end > fault && end[-1] == value)
686 end--;
687
688 slab_bug(s, "%s overwritten", what);
689 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
690 fault, end - 1, fault[0], value);
691 print_trailer(s, page, object);
692
693 restore_bytes(s, what, value, fault, end);
694 return 0;
695}
696
697/*
698 * Object layout:
699 *
700 * object address
701 * Bytes of the object to be managed.
702 * If the freepointer may overlay the object then the free
703 * pointer is the first word of the object.
704 *
705 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
706 * 0xa5 (POISON_END)
707 *
708 * object + s->objsize
709 * Padding to reach word boundary. This is also used for Redzoning.
710 * Padding is extended by another word if Redzoning is enabled and
711 * objsize == inuse.
712 *
713 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
714 * 0xcc (RED_ACTIVE) for objects in use.
715 *
716 * object + s->inuse
717 * Meta data starts here.
718 *
719 * A. Free pointer (if we cannot overwrite object on free)
720 * B. Tracking data for SLAB_STORE_USER
721 * C. Padding to reach required alignment boundary or at mininum
722 * one word if debugging is on to be able to detect writes
723 * before the word boundary.
724 *
725 * Padding is done using 0x5a (POISON_INUSE)
726 *
727 * object + s->size
728 * Nothing is used beyond s->size.
729 *
730 * If slabcaches are merged then the objsize and inuse boundaries are mostly
731 * ignored. And therefore no slab options that rely on these boundaries
732 * may be used with merged slabcaches.
733 */
734
735static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
736{
737 unsigned long off = s->inuse; /* The end of info */
738
739 if (s->offset)
740 /* Freepointer is placed after the object. */
741 off += sizeof(void *);
742
743 if (s->flags & SLAB_STORE_USER)
744 /* We also have user information there */
745 off += 2 * sizeof(struct track);
746
747 if (s->size == off)
748 return 1;
749
750 return check_bytes_and_report(s, page, p, "Object padding",
751 p + off, POISON_INUSE, s->size - off);
752}
753
754/* Check the pad bytes at the end of a slab page */
755static int slab_pad_check(struct kmem_cache *s, struct page *page)
756{
757 u8 *start;
758 u8 *fault;
759 u8 *end;
760 int length;
761 int remainder;
762
763 if (!(s->flags & SLAB_POISON))
764 return 1;
765
766 start = page_address(page);
767 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
768 end = start + length;
769 remainder = length % s->size;
770 if (!remainder)
771 return 1;
772
773 fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
774 if (!fault)
775 return 1;
776 while (end > fault && end[-1] == POISON_INUSE)
777 end--;
778
779 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
780 print_section("Padding ", end - remainder, remainder);
781
782 restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
783 return 0;
784}
785
786static int check_object(struct kmem_cache *s, struct page *page,
787 void *object, u8 val)
788{
789 u8 *p = object;
790 u8 *endobject = object + s->objsize;
791
792 if (s->flags & SLAB_RED_ZONE) {
793 if (!check_bytes_and_report(s, page, object, "Redzone",
794 endobject, val, s->inuse - s->objsize))
795 return 0;
796 } else {
797 if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
798 check_bytes_and_report(s, page, p, "Alignment padding",
799 endobject, POISON_INUSE, s->inuse - s->objsize);
800 }
801 }
802
803 if (s->flags & SLAB_POISON) {
804 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
805 (!check_bytes_and_report(s, page, p, "Poison", p,
806 POISON_FREE, s->objsize - 1) ||
807 !check_bytes_and_report(s, page, p, "Poison",
808 p + s->objsize - 1, POISON_END, 1)))
809 return 0;
810 /*
811 * check_pad_bytes cleans up on its own.
812 */
813 check_pad_bytes(s, page, p);
814 }
815
816 if (!s->offset && val == SLUB_RED_ACTIVE)
817 /*
818 * Object and freepointer overlap. Cannot check
819 * freepointer while object is allocated.
820 */
821 return 1;
822
823 /* Check free pointer validity */
824 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
825 object_err(s, page, p, "Freepointer corrupt");
826 /*
827 * No choice but to zap it and thus lose the remainder
828 * of the free objects in this slab. May cause
829 * another error because the object count is now wrong.
830 */
831 set_freepointer(s, p, NULL);
832 return 0;
833 }
834 return 1;
835}
836
837static int check_slab(struct kmem_cache *s, struct page *page)
838{
839 int maxobj;
840
841 VM_BUG_ON(!irqs_disabled());
842
843 if (!PageSlab(page)) {
844 slab_err(s, page, "Not a valid slab page");
845 return 0;
846 }
847
848 maxobj = order_objects(compound_order(page), s->size, s->reserved);
849 if (page->objects > maxobj) {
850 slab_err(s, page, "objects %u > max %u",
851 s->name, page->objects, maxobj);
852 return 0;
853 }
854 if (page->inuse > page->objects) {
855 slab_err(s, page, "inuse %u > max %u",
856 s->name, page->inuse, page->objects);
857 return 0;
858 }
859 /* Slab_pad_check fixes things up after itself */
860 slab_pad_check(s, page);
861 return 1;
862}
863
864/*
865 * Determine if a certain object on a page is on the freelist. Must hold the
866 * slab lock to guarantee that the chains are in a consistent state.
867 */
868static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
869{
870 int nr = 0;
871 void *fp;
872 void *object = NULL;
873 unsigned long max_objects;
874
875 fp = page->freelist;
876 while (fp && nr <= page->objects) {
877 if (fp == search)
878 return 1;
879 if (!check_valid_pointer(s, page, fp)) {
880 if (object) {
881 object_err(s, page, object,
882 "Freechain corrupt");
883 set_freepointer(s, object, NULL);
884 break;
885 } else {
886 slab_err(s, page, "Freepointer corrupt");
887 page->freelist = NULL;
888 page->inuse = page->objects;
889 slab_fix(s, "Freelist cleared");
890 return 0;
891 }
892 break;
893 }
894 object = fp;
895 fp = get_freepointer(s, object);
896 nr++;
897 }
898
899 max_objects = order_objects(compound_order(page), s->size, s->reserved);
900 if (max_objects > MAX_OBJS_PER_PAGE)
901 max_objects = MAX_OBJS_PER_PAGE;
902
903 if (page->objects != max_objects) {
904 slab_err(s, page, "Wrong number of objects. Found %d but "
905 "should be %d", page->objects, max_objects);
906 page->objects = max_objects;
907 slab_fix(s, "Number of objects adjusted.");
908 }
909 if (page->inuse != page->objects - nr) {
910 slab_err(s, page, "Wrong object count. Counter is %d but "
911 "counted were %d", page->inuse, page->objects - nr);
912 page->inuse = page->objects - nr;
913 slab_fix(s, "Object count adjusted.");
914 }
915 return search == NULL;
916}
917
918static void trace(struct kmem_cache *s, struct page *page, void *object,
919 int alloc)
920{
921 if (s->flags & SLAB_TRACE) {
922 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
923 s->name,
924 alloc ? "alloc" : "free",
925 object, page->inuse,
926 page->freelist);
927
928 if (!alloc)
929 print_section("Object ", (void *)object, s->objsize);
930
931 dump_stack();
932 }
933}
934
935/*
936 * Hooks for other subsystems that check memory allocations. In a typical
937 * production configuration these hooks all should produce no code at all.
938 */
939static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
940{
941 flags &= gfp_allowed_mask;
942 lockdep_trace_alloc(flags);
943 might_sleep_if(flags & __GFP_WAIT);
944
945 return should_failslab(s->objsize, flags, s->flags);
946}
947
948static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
949{
950 flags &= gfp_allowed_mask;
951 kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
952 kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
953}
954
955static inline void slab_free_hook(struct kmem_cache *s, void *x)
956{
957 kmemleak_free_recursive(x, s->flags);
958
959 /*
960 * Trouble is that we may no longer disable interupts in the fast path
961 * So in order to make the debug calls that expect irqs to be
962 * disabled we need to disable interrupts temporarily.
963 */
964#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
965 {
966 unsigned long flags;
967
968 local_irq_save(flags);
969 kmemcheck_slab_free(s, x, s->objsize);
970 debug_check_no_locks_freed(x, s->objsize);
971 local_irq_restore(flags);
972 }
973#endif
974 if (!(s->flags & SLAB_DEBUG_OBJECTS))
975 debug_check_no_obj_freed(x, s->objsize);
976}
977
978/*
979 * Tracking of fully allocated slabs for debugging purposes.
980 *
981 * list_lock must be held.
982 */
983static void add_full(struct kmem_cache *s,
984 struct kmem_cache_node *n, struct page *page)
985{
986 if (!(s->flags & SLAB_STORE_USER))
987 return;
988
989 list_add(&page->lru, &n->full);
990}
991
992/*
993 * list_lock must be held.
994 */
995static void remove_full(struct kmem_cache *s, struct page *page)
996{
997 if (!(s->flags & SLAB_STORE_USER))
998 return;
999
1000 list_del(&page->lru);
1001}
1002
1003/* Tracking of the number of slabs for debugging purposes */
1004static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1005{
1006 struct kmem_cache_node *n = get_node(s, node);
1007
1008 return atomic_long_read(&n->nr_slabs);
1009}
1010
1011static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1012{
1013 return atomic_long_read(&n->nr_slabs);
1014}
1015
1016static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1017{
1018 struct kmem_cache_node *n = get_node(s, node);
1019
1020 /*
1021 * May be called early in order to allocate a slab for the
1022 * kmem_cache_node structure. Solve the chicken-egg
1023 * dilemma by deferring the increment of the count during
1024 * bootstrap (see early_kmem_cache_node_alloc).
1025 */
1026 if (n) {
1027 atomic_long_inc(&n->nr_slabs);
1028 atomic_long_add(objects, &n->total_objects);
1029 }
1030}
1031static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1032{
1033 struct kmem_cache_node *n = get_node(s, node);
1034
1035 atomic_long_dec(&n->nr_slabs);
1036 atomic_long_sub(objects, &n->total_objects);
1037}
1038
1039/* Object debug checks for alloc/free paths */
1040static void setup_object_debug(struct kmem_cache *s, struct page *page,
1041 void *object)
1042{
1043 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1044 return;
1045
1046 init_object(s, object, SLUB_RED_INACTIVE);
1047 init_tracking(s, object);
1048}
1049
1050static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1051 void *object, unsigned long addr)
1052{
1053 if (!check_slab(s, page))
1054 goto bad;
1055
1056 if (!check_valid_pointer(s, page, object)) {
1057 object_err(s, page, object, "Freelist Pointer check fails");
1058 goto bad;
1059 }
1060
1061 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1062 goto bad;
1063
1064 /* Success perform special debug activities for allocs */
1065 if (s->flags & SLAB_STORE_USER)
1066 set_track(s, object, TRACK_ALLOC, addr);
1067 trace(s, page, object, 1);
1068 init_object(s, object, SLUB_RED_ACTIVE);
1069 return 1;
1070
1071bad:
1072 if (PageSlab(page)) {
1073 /*
1074 * If this is a slab page then lets do the best we can
1075 * to avoid issues in the future. Marking all objects
1076 * as used avoids touching the remaining objects.
1077 */
1078 slab_fix(s, "Marking all objects used");
1079 page->inuse = page->objects;
1080 page->freelist = NULL;
1081 }
1082 return 0;
1083}
1084
1085static noinline int free_debug_processing(struct kmem_cache *s,
1086 struct page *page, void *object, unsigned long addr)
1087{
1088 unsigned long flags;
1089 int rc = 0;
1090
1091 local_irq_save(flags);
1092 slab_lock(page);
1093
1094 if (!check_slab(s, page))
1095 goto fail;
1096
1097 if (!check_valid_pointer(s, page, object)) {
1098 slab_err(s, page, "Invalid object pointer 0x%p", object);
1099 goto fail;
1100 }
1101
1102 if (on_freelist(s, page, object)) {
1103 object_err(s, page, object, "Object already free");
1104 goto fail;
1105 }
1106
1107 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1108 goto out;
1109
1110 if (unlikely(s != page->slab)) {
1111 if (!PageSlab(page)) {
1112 slab_err(s, page, "Attempt to free object(0x%p) "
1113 "outside of slab", object);
1114 } else if (!page->slab) {
1115 printk(KERN_ERR
1116 "SLUB <none>: no slab for object 0x%p.\n",
1117 object);
1118 dump_stack();
1119 } else
1120 object_err(s, page, object,
1121 "page slab pointer corrupt.");
1122 goto fail;
1123 }
1124
1125 if (s->flags & SLAB_STORE_USER)
1126 set_track(s, object, TRACK_FREE, addr);
1127 trace(s, page, object, 0);
1128 init_object(s, object, SLUB_RED_INACTIVE);
1129 rc = 1;
1130out:
1131 slab_unlock(page);
1132 local_irq_restore(flags);
1133 return rc;
1134
1135fail:
1136 slab_fix(s, "Object at 0x%p not freed", object);
1137 goto out;
1138}
1139
1140static int __init setup_slub_debug(char *str)
1141{
1142 slub_debug = DEBUG_DEFAULT_FLAGS;
1143 if (*str++ != '=' || !*str)
1144 /*
1145 * No options specified. Switch on full debugging.
1146 */
1147 goto out;
1148
1149 if (*str == ',')
1150 /*
1151 * No options but restriction on slabs. This means full
1152 * debugging for slabs matching a pattern.
1153 */
1154 goto check_slabs;
1155
1156 if (tolower(*str) == 'o') {
1157 /*
1158 * Avoid enabling debugging on caches if its minimum order
1159 * would increase as a result.
1160 */
1161 disable_higher_order_debug = 1;
1162 goto out;
1163 }
1164
1165 slub_debug = 0;
1166 if (*str == '-')
1167 /*
1168 * Switch off all debugging measures.
1169 */
1170 goto out;
1171
1172 /*
1173 * Determine which debug features should be switched on
1174 */
1175 for (; *str && *str != ','; str++) {
1176 switch (tolower(*str)) {
1177 case 'f':
1178 slub_debug |= SLAB_DEBUG_FREE;
1179 break;
1180 case 'z':
1181 slub_debug |= SLAB_RED_ZONE;
1182 break;
1183 case 'p':
1184 slub_debug |= SLAB_POISON;
1185 break;
1186 case 'u':
1187 slub_debug |= SLAB_STORE_USER;
1188 break;
1189 case 't':
1190 slub_debug |= SLAB_TRACE;
1191 break;
1192 case 'a':
1193 slub_debug |= SLAB_FAILSLAB;
1194 break;
1195 default:
1196 printk(KERN_ERR "slub_debug option '%c' "
1197 "unknown. skipped\n", *str);
1198 }
1199 }
1200
1201check_slabs:
1202 if (*str == ',')
1203 slub_debug_slabs = str + 1;
1204out:
1205 return 1;
1206}
1207
1208__setup("slub_debug", setup_slub_debug);
1209
1210static unsigned long kmem_cache_flags(unsigned long objsize,
1211 unsigned long flags, const char *name,
1212 void (*ctor)(void *))
1213{
1214 /*
1215 * Enable debugging if selected on the kernel commandline.
1216 */
1217 if (slub_debug && (!slub_debug_slabs ||
1218 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1219 flags |= slub_debug;
1220
1221 return flags;
1222}
1223#else
1224static inline void setup_object_debug(struct kmem_cache *s,
1225 struct page *page, void *object) {}
1226
1227static inline int alloc_debug_processing(struct kmem_cache *s,
1228 struct page *page, void *object, unsigned long addr) { return 0; }
1229
1230static inline int free_debug_processing(struct kmem_cache *s,
1231 struct page *page, void *object, unsigned long addr) { return 0; }
1232
1233static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1234 { return 1; }
1235static inline int check_object(struct kmem_cache *s, struct page *page,
1236 void *object, u8 val) { return 1; }
1237static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1238 struct page *page) {}
1239static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1240static inline unsigned long kmem_cache_flags(unsigned long objsize,
1241 unsigned long flags, const char *name,
1242 void (*ctor)(void *))
1243{
1244 return flags;
1245}
1246#define slub_debug 0
1247
1248#define disable_higher_order_debug 0
1249
1250static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1251 { return 0; }
1252static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1253 { return 0; }
1254static inline void inc_slabs_node(struct kmem_cache *s, int node,
1255 int objects) {}
1256static inline void dec_slabs_node(struct kmem_cache *s, int node,
1257 int objects) {}
1258
1259static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1260 { return 0; }
1261
1262static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1263 void *object) {}
1264
1265static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
1266
1267#endif /* CONFIG_SLUB_DEBUG */
1268
1269/*
1270 * Slab allocation and freeing
1271 */
1272static inline struct page *alloc_slab_page(gfp_t flags, int node,
1273 struct kmem_cache_order_objects oo)
1274{
1275 int order = oo_order(oo);
1276
1277 flags |= __GFP_NOTRACK;
1278
1279 if (node == NUMA_NO_NODE)
1280 return alloc_pages(flags, order);
1281 else
1282 return alloc_pages_exact_node(node, flags, order);
1283}
1284
1285static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1286{
1287 struct page *page;
1288 struct kmem_cache_order_objects oo = s->oo;
1289 gfp_t alloc_gfp;
1290
1291 flags &= gfp_allowed_mask;
1292
1293 if (flags & __GFP_WAIT)
1294 local_irq_enable();
1295
1296 flags |= s->allocflags;
1297
1298 /*
1299 * Let the initial higher-order allocation fail under memory pressure
1300 * so we fall-back to the minimum order allocation.
1301 */
1302 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1303
1304 page = alloc_slab_page(alloc_gfp, node, oo);
1305 if (unlikely(!page)) {
1306 oo = s->min;
1307 /*
1308 * Allocation may have failed due to fragmentation.
1309 * Try a lower order alloc if possible
1310 */
1311 page = alloc_slab_page(flags, node, oo);
1312
1313 if (page)
1314 stat(s, ORDER_FALLBACK);
1315 }
1316
1317 if (flags & __GFP_WAIT)
1318 local_irq_disable();
1319
1320 if (!page)
1321 return NULL;
1322
1323 if (kmemcheck_enabled
1324 && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1325 int pages = 1 << oo_order(oo);
1326
1327 kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1328
1329 /*
1330 * Objects from caches that have a constructor don't get
1331 * cleared when they're allocated, so we need to do it here.
1332 */
1333 if (s->ctor)
1334 kmemcheck_mark_uninitialized_pages(page, pages);
1335 else
1336 kmemcheck_mark_unallocated_pages(page, pages);
1337 }
1338
1339 page->objects = oo_objects(oo);
1340 mod_zone_page_state(page_zone(page),
1341 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1342 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1343 1 << oo_order(oo));
1344
1345 return page;
1346}
1347
1348static void setup_object(struct kmem_cache *s, struct page *page,
1349 void *object)
1350{
1351 setup_object_debug(s, page, object);
1352 if (unlikely(s->ctor))
1353 s->ctor(object);
1354}
1355
1356static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1357{
1358 struct page *page;
1359 void *start;
1360 void *last;
1361 void *p;
1362
1363 BUG_ON(flags & GFP_SLAB_BUG_MASK);
1364
1365 page = allocate_slab(s,
1366 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1367 if (!page)
1368 goto out;
1369
1370 inc_slabs_node(s, page_to_nid(page), page->objects);
1371 page->slab = s;
1372 __SetPageSlab(page);
1373
1374 start = page_address(page);
1375
1376 if (unlikely(s->flags & SLAB_POISON))
1377 memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
1378
1379 last = start;
1380 for_each_object(p, s, start, page->objects) {
1381 setup_object(s, page, last);
1382 set_freepointer(s, last, p);
1383 last = p;
1384 }
1385 setup_object(s, page, last);
1386 set_freepointer(s, last, NULL);
1387
1388 page->freelist = start;
1389 page->inuse = page->objects;
1390 page->frozen = 1;
1391out:
1392 return page;
1393}
1394
1395static void __free_slab(struct kmem_cache *s, struct page *page)
1396{
1397 int order = compound_order(page);
1398 int pages = 1 << order;
1399
1400 if (kmem_cache_debug(s)) {
1401 void *p;
1402
1403 slab_pad_check(s, page);
1404 for_each_object(p, s, page_address(page),
1405 page->objects)
1406 check_object(s, page, p, SLUB_RED_INACTIVE);
1407 }
1408
1409 kmemcheck_free_shadow(page, compound_order(page));
1410
1411 mod_zone_page_state(page_zone(page),
1412 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1413 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1414 -pages);
1415
1416 __ClearPageSlab(page);
1417 reset_page_mapcount(page);
1418 if (current->reclaim_state)
1419 current->reclaim_state->reclaimed_slab += pages;
1420 __free_pages(page, order);
1421}
1422
1423#define need_reserve_slab_rcu \
1424 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1425
1426static void rcu_free_slab(struct rcu_head *h)
1427{
1428 struct page *page;
1429
1430 if (need_reserve_slab_rcu)
1431 page = virt_to_head_page(h);
1432 else
1433 page = container_of((struct list_head *)h, struct page, lru);
1434
1435 __free_slab(page->slab, page);
1436}
1437
1438static void free_slab(struct kmem_cache *s, struct page *page)
1439{
1440 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1441 struct rcu_head *head;
1442
1443 if (need_reserve_slab_rcu) {
1444 int order = compound_order(page);
1445 int offset = (PAGE_SIZE << order) - s->reserved;
1446
1447 VM_BUG_ON(s->reserved != sizeof(*head));
1448 head = page_address(page) + offset;
1449 } else {
1450 /*
1451 * RCU free overloads the RCU head over the LRU
1452 */
1453 head = (void *)&page->lru;
1454 }
1455
1456 call_rcu(head, rcu_free_slab);
1457 } else
1458 __free_slab(s, page);
1459}
1460
1461static void discard_slab(struct kmem_cache *s, struct page *page)
1462{
1463 dec_slabs_node(s, page_to_nid(page), page->objects);
1464 free_slab(s, page);
1465}
1466
1467/*
1468 * Management of partially allocated slabs.
1469 *
1470 * list_lock must be held.
1471 */
1472static inline void add_partial(struct kmem_cache_node *n,
1473 struct page *page, int tail)
1474{
1475 n->nr_partial++;
1476 if (tail == DEACTIVATE_TO_TAIL)
1477 list_add_tail(&page->lru, &n->partial);
1478 else
1479 list_add(&page->lru, &n->partial);
1480}
1481
1482/*
1483 * list_lock must be held.
1484 */
1485static inline void remove_partial(struct kmem_cache_node *n,
1486 struct page *page)
1487{
1488 list_del(&page->lru);
1489 n->nr_partial--;
1490}
1491
1492/*
1493 * Lock slab, remove from the partial list and put the object into the
1494 * per cpu freelist.
1495 *
1496 * Returns a list of objects or NULL if it fails.
1497 *
1498 * Must hold list_lock.
1499 */
1500static inline void *acquire_slab(struct kmem_cache *s,
1501 struct kmem_cache_node *n, struct page *page,
1502 int mode)
1503{
1504 void *freelist;
1505 unsigned long counters;
1506 struct page new;
1507
1508 /*
1509 * Zap the freelist and set the frozen bit.
1510 * The old freelist is the list of objects for the
1511 * per cpu allocation list.
1512 */
1513 do {
1514 freelist = page->freelist;
1515 counters = page->counters;
1516 new.counters = counters;
1517 if (mode) {
1518 new.inuse = page->objects;
1519 new.freelist = NULL;
1520 } else {
1521 new.freelist = freelist;
1522 }
1523
1524 VM_BUG_ON(new.frozen);
1525 new.frozen = 1;
1526
1527 } while (!__cmpxchg_double_slab(s, page,
1528 freelist, counters,
1529 new.freelist, new.counters,
1530 "lock and freeze"));
1531
1532 remove_partial(n, page);
1533 return freelist;
1534}
1535
1536static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1537
1538/*
1539 * Try to allocate a partial slab from a specific node.
1540 */
1541static void *get_partial_node(struct kmem_cache *s,
1542 struct kmem_cache_node *n, struct kmem_cache_cpu *c)
1543{
1544 struct page *page, *page2;
1545 void *object = NULL;
1546
1547 /*
1548 * Racy check. If we mistakenly see no partial slabs then we
1549 * just allocate an empty slab. If we mistakenly try to get a
1550 * partial slab and there is none available then get_partials()
1551 * will return NULL.
1552 */
1553 if (!n || !n->nr_partial)
1554 return NULL;
1555
1556 spin_lock(&n->list_lock);
1557 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1558 void *t = acquire_slab(s, n, page, object == NULL);
1559 int available;
1560
1561 if (!t)
1562 break;
1563
1564 if (!object) {
1565 c->page = page;
1566 c->node = page_to_nid(page);
1567 stat(s, ALLOC_FROM_PARTIAL);
1568 object = t;
1569 available = page->objects - page->inuse;
1570 } else {
1571 available = put_cpu_partial(s, page, 0);
1572 stat(s, CPU_PARTIAL_NODE);
1573 }
1574 if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
1575 break;
1576
1577 }
1578 spin_unlock(&n->list_lock);
1579 return object;
1580}
1581
1582/*
1583 * Get a page from somewhere. Search in increasing NUMA distances.
1584 */
1585static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1586 struct kmem_cache_cpu *c)
1587{
1588#ifdef CONFIG_NUMA
1589 struct zonelist *zonelist;
1590 struct zoneref *z;
1591 struct zone *zone;
1592 enum zone_type high_zoneidx = gfp_zone(flags);
1593 void *object;
1594 unsigned int cpuset_mems_cookie;
1595
1596 /*
1597 * The defrag ratio allows a configuration of the tradeoffs between
1598 * inter node defragmentation and node local allocations. A lower
1599 * defrag_ratio increases the tendency to do local allocations
1600 * instead of attempting to obtain partial slabs from other nodes.
1601 *
1602 * If the defrag_ratio is set to 0 then kmalloc() always
1603 * returns node local objects. If the ratio is higher then kmalloc()
1604 * may return off node objects because partial slabs are obtained
1605 * from other nodes and filled up.
1606 *
1607 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1608 * defrag_ratio = 1000) then every (well almost) allocation will
1609 * first attempt to defrag slab caches on other nodes. This means
1610 * scanning over all nodes to look for partial slabs which may be
1611 * expensive if we do it every time we are trying to find a slab
1612 * with available objects.
1613 */
1614 if (!s->remote_node_defrag_ratio ||
1615 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1616 return NULL;
1617
1618 do {
1619 cpuset_mems_cookie = get_mems_allowed();
1620 zonelist = node_zonelist(slab_node(current->mempolicy), flags);
1621 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1622 struct kmem_cache_node *n;
1623
1624 n = get_node(s, zone_to_nid(zone));
1625
1626 if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1627 n->nr_partial > s->min_partial) {
1628 object = get_partial_node(s, n, c);
1629 if (object) {
1630 /*
1631 * Return the object even if
1632 * put_mems_allowed indicated that
1633 * the cpuset mems_allowed was
1634 * updated in parallel. It's a
1635 * harmless race between the alloc
1636 * and the cpuset update.
1637 */
1638 put_mems_allowed(cpuset_mems_cookie);
1639 return object;
1640 }
1641 }
1642 }
1643 } while (!put_mems_allowed(cpuset_mems_cookie));
1644#endif
1645 return NULL;
1646}
1647
1648/*
1649 * Get a partial page, lock it and return it.
1650 */
1651static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1652 struct kmem_cache_cpu *c)
1653{
1654 void *object;
1655 int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
1656
1657 object = get_partial_node(s, get_node(s, searchnode), c);
1658 if (object || node != NUMA_NO_NODE)
1659 return object;
1660
1661 return get_any_partial(s, flags, c);
1662}
1663
1664#ifdef CONFIG_PREEMPT
1665/*
1666 * Calculate the next globally unique transaction for disambiguiation
1667 * during cmpxchg. The transactions start with the cpu number and are then
1668 * incremented by CONFIG_NR_CPUS.
1669 */
1670#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1671#else
1672/*
1673 * No preemption supported therefore also no need to check for
1674 * different cpus.
1675 */
1676#define TID_STEP 1
1677#endif
1678
1679static inline unsigned long next_tid(unsigned long tid)
1680{
1681 return tid + TID_STEP;
1682}
1683
1684static inline unsigned int tid_to_cpu(unsigned long tid)
1685{
1686 return tid % TID_STEP;
1687}
1688
1689static inline unsigned long tid_to_event(unsigned long tid)
1690{
1691 return tid / TID_STEP;
1692}
1693
1694static inline unsigned int init_tid(int cpu)
1695{
1696 return cpu;
1697}
1698
1699static inline void note_cmpxchg_failure(const char *n,
1700 const struct kmem_cache *s, unsigned long tid)
1701{
1702#ifdef SLUB_DEBUG_CMPXCHG
1703 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1704
1705 printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1706
1707#ifdef CONFIG_PREEMPT
1708 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1709 printk("due to cpu change %d -> %d\n",
1710 tid_to_cpu(tid), tid_to_cpu(actual_tid));
1711 else
1712#endif
1713 if (tid_to_event(tid) != tid_to_event(actual_tid))
1714 printk("due to cpu running other code. Event %ld->%ld\n",
1715 tid_to_event(tid), tid_to_event(actual_tid));
1716 else
1717 printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1718 actual_tid, tid, next_tid(tid));
1719#endif
1720 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1721}
1722
1723void init_kmem_cache_cpus(struct kmem_cache *s)
1724{
1725 int cpu;
1726
1727 for_each_possible_cpu(cpu)
1728 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1729}
1730
1731/*
1732 * Remove the cpu slab
1733 */
1734static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1735{
1736 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1737 struct page *page = c->page;
1738 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1739 int lock = 0;
1740 enum slab_modes l = M_NONE, m = M_NONE;
1741 void *freelist;
1742 void *nextfree;
1743 int tail = DEACTIVATE_TO_HEAD;
1744 struct page new;
1745 struct page old;
1746
1747 if (page->freelist) {
1748 stat(s, DEACTIVATE_REMOTE_FREES);
1749 tail = DEACTIVATE_TO_TAIL;
1750 }
1751
1752 c->tid = next_tid(c->tid);
1753 c->page = NULL;
1754 freelist = c->freelist;
1755 c->freelist = NULL;
1756
1757 /*
1758 * Stage one: Free all available per cpu objects back
1759 * to the page freelist while it is still frozen. Leave the
1760 * last one.
1761 *
1762 * There is no need to take the list->lock because the page
1763 * is still frozen.
1764 */
1765 while (freelist && (nextfree = get_freepointer(s, freelist))) {
1766 void *prior;
1767 unsigned long counters;
1768
1769 do {
1770 prior = page->freelist;
1771 counters = page->counters;
1772 set_freepointer(s, freelist, prior);
1773 new.counters = counters;
1774 new.inuse--;
1775 VM_BUG_ON(!new.frozen);
1776
1777 } while (!__cmpxchg_double_slab(s, page,
1778 prior, counters,
1779 freelist, new.counters,
1780 "drain percpu freelist"));
1781
1782 freelist = nextfree;
1783 }
1784
1785 /*
1786 * Stage two: Ensure that the page is unfrozen while the
1787 * list presence reflects the actual number of objects
1788 * during unfreeze.
1789 *
1790 * We setup the list membership and then perform a cmpxchg
1791 * with the count. If there is a mismatch then the page
1792 * is not unfrozen but the page is on the wrong list.
1793 *
1794 * Then we restart the process which may have to remove
1795 * the page from the list that we just put it on again
1796 * because the number of objects in the slab may have
1797 * changed.
1798 */
1799redo:
1800
1801 old.freelist = page->freelist;
1802 old.counters = page->counters;
1803 VM_BUG_ON(!old.frozen);
1804
1805 /* Determine target state of the slab */
1806 new.counters = old.counters;
1807 if (freelist) {
1808 new.inuse--;
1809 set_freepointer(s, freelist, old.freelist);
1810 new.freelist = freelist;
1811 } else
1812 new.freelist = old.freelist;
1813
1814 new.frozen = 0;
1815
1816 if (!new.inuse && n->nr_partial > s->min_partial)
1817 m = M_FREE;
1818 else if (new.freelist) {
1819 m = M_PARTIAL;
1820 if (!lock) {
1821 lock = 1;
1822 /*
1823 * Taking the spinlock removes the possiblity
1824 * that acquire_slab() will see a slab page that
1825 * is frozen
1826 */
1827 spin_lock(&n->list_lock);
1828 }
1829 } else {
1830 m = M_FULL;
1831 if (kmem_cache_debug(s) && !lock) {
1832 lock = 1;
1833 /*
1834 * This also ensures that the scanning of full
1835 * slabs from diagnostic functions will not see
1836 * any frozen slabs.
1837 */
1838 spin_lock(&n->list_lock);
1839 }
1840 }
1841
1842 if (l != m) {
1843
1844 if (l == M_PARTIAL)
1845
1846 remove_partial(n, page);
1847
1848 else if (l == M_FULL)
1849
1850 remove_full(s, page);
1851
1852 if (m == M_PARTIAL) {
1853
1854 add_partial(n, page, tail);
1855 stat(s, tail);
1856
1857 } else if (m == M_FULL) {
1858
1859 stat(s, DEACTIVATE_FULL);
1860 add_full(s, n, page);
1861
1862 }
1863 }
1864
1865 l = m;
1866 if (!__cmpxchg_double_slab(s, page,
1867 old.freelist, old.counters,
1868 new.freelist, new.counters,
1869 "unfreezing slab"))
1870 goto redo;
1871
1872 if (lock)
1873 spin_unlock(&n->list_lock);
1874
1875 if (m == M_FREE) {
1876 stat(s, DEACTIVATE_EMPTY);
1877 discard_slab(s, page);
1878 stat(s, FREE_SLAB);
1879 }
1880}
1881
1882/* Unfreeze all the cpu partial slabs */
1883static void unfreeze_partials(struct kmem_cache *s)
1884{
1885 struct kmem_cache_node *n = NULL;
1886 struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
1887 struct page *page, *discard_page = NULL;
1888
1889 while ((page = c->partial)) {
1890 enum slab_modes { M_PARTIAL, M_FREE };
1891 enum slab_modes l, m;
1892 struct page new;
1893 struct page old;
1894
1895 c->partial = page->next;
1896 l = M_FREE;
1897
1898 do {
1899
1900 old.freelist = page->freelist;
1901 old.counters = page->counters;
1902 VM_BUG_ON(!old.frozen);
1903
1904 new.counters = old.counters;
1905 new.freelist = old.freelist;
1906
1907 new.frozen = 0;
1908
1909 if (!new.inuse && (!n || n->nr_partial > s->min_partial))
1910 m = M_FREE;
1911 else {
1912 struct kmem_cache_node *n2 = get_node(s,
1913 page_to_nid(page));
1914
1915 m = M_PARTIAL;
1916 if (n != n2) {
1917 if (n)
1918 spin_unlock(&n->list_lock);
1919
1920 n = n2;
1921 spin_lock(&n->list_lock);
1922 }
1923 }
1924
1925 if (l != m) {
1926 if (l == M_PARTIAL) {
1927 remove_partial(n, page);
1928 stat(s, FREE_REMOVE_PARTIAL);
1929 } else {
1930 add_partial(n, page,
1931 DEACTIVATE_TO_TAIL);
1932 stat(s, FREE_ADD_PARTIAL);
1933 }
1934
1935 l = m;
1936 }
1937
1938 } while (!cmpxchg_double_slab(s, page,
1939 old.freelist, old.counters,
1940 new.freelist, new.counters,
1941 "unfreezing slab"));
1942
1943 if (m == M_FREE) {
1944 page->next = discard_page;
1945 discard_page = page;
1946 }
1947 }
1948
1949 if (n)
1950 spin_unlock(&n->list_lock);
1951
1952 while (discard_page) {
1953 page = discard_page;
1954 discard_page = discard_page->next;
1955
1956 stat(s, DEACTIVATE_EMPTY);
1957 discard_slab(s, page);
1958 stat(s, FREE_SLAB);
1959 }
1960}
1961
1962/*
1963 * Put a page that was just frozen (in __slab_free) into a partial page
1964 * slot if available. This is done without interrupts disabled and without
1965 * preemption disabled. The cmpxchg is racy and may put the partial page
1966 * onto a random cpus partial slot.
1967 *
1968 * If we did not find a slot then simply move all the partials to the
1969 * per node partial list.
1970 */
1971int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
1972{
1973 struct page *oldpage;
1974 int pages;
1975 int pobjects;
1976
1977 do {
1978 pages = 0;
1979 pobjects = 0;
1980 oldpage = this_cpu_read(s->cpu_slab->partial);
1981
1982 if (oldpage) {
1983 pobjects = oldpage->pobjects;
1984 pages = oldpage->pages;
1985 if (drain && pobjects > s->cpu_partial) {
1986 unsigned long flags;
1987 /*
1988 * partial array is full. Move the existing
1989 * set to the per node partial list.
1990 */
1991 local_irq_save(flags);
1992 unfreeze_partials(s);
1993 local_irq_restore(flags);
1994 pobjects = 0;
1995 pages = 0;
1996 stat(s, CPU_PARTIAL_DRAIN);
1997 }
1998 }
1999
2000 pages++;
2001 pobjects += page->objects - page->inuse;
2002
2003 page->pages = pages;
2004 page->pobjects = pobjects;
2005 page->next = oldpage;
2006
2007 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
2008 return pobjects;
2009}
2010
2011static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2012{
2013 stat(s, CPUSLAB_FLUSH);
2014 deactivate_slab(s, c);
2015}
2016
2017/*
2018 * Flush cpu slab.
2019 *
2020 * Called from IPI handler with interrupts disabled.
2021 */
2022static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2023{
2024 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2025
2026 if (likely(c)) {
2027 if (c->page)
2028 flush_slab(s, c);
2029
2030 unfreeze_partials(s);
2031 }
2032}
2033
2034static void flush_cpu_slab(void *d)
2035{
2036 struct kmem_cache *s = d;
2037
2038 __flush_cpu_slab(s, smp_processor_id());
2039}
2040
2041static bool has_cpu_slab(int cpu, void *info)
2042{
2043 struct kmem_cache *s = info;
2044 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2045
2046 return c->page || c->partial;
2047}
2048
2049static void flush_all(struct kmem_cache *s)
2050{
2051 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2052}
2053
2054/*
2055 * Check if the objects in a per cpu structure fit numa
2056 * locality expectations.
2057 */
2058static inline int node_match(struct kmem_cache_cpu *c, int node)
2059{
2060#ifdef CONFIG_NUMA
2061 if (node != NUMA_NO_NODE && c->node != node)
2062 return 0;
2063#endif
2064 return 1;
2065}
2066
2067static int count_free(struct page *page)
2068{
2069 return page->objects - page->inuse;
2070}
2071
2072static unsigned long count_partial(struct kmem_cache_node *n,
2073 int (*get_count)(struct page *))
2074{
2075 unsigned long flags;
2076 unsigned long x = 0;
2077 struct page *page;
2078
2079 spin_lock_irqsave(&n->list_lock, flags);
2080 list_for_each_entry(page, &n->partial, lru)
2081 x += get_count(page);
2082 spin_unlock_irqrestore(&n->list_lock, flags);
2083 return x;
2084}
2085
2086static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2087{
2088#ifdef CONFIG_SLUB_DEBUG
2089 return atomic_long_read(&n->total_objects);
2090#else
2091 return 0;
2092#endif
2093}
2094
2095static noinline void
2096slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2097{
2098 int node;
2099
2100 printk(KERN_WARNING
2101 "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2102 nid, gfpflags);
2103 printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
2104 "default order: %d, min order: %d\n", s->name, s->objsize,
2105 s->size, oo_order(s->oo), oo_order(s->min));
2106
2107 if (oo_order(s->min) > get_order(s->objsize))
2108 printk(KERN_WARNING " %s debugging increased min order, use "
2109 "slub_debug=O to disable.\n", s->name);
2110
2111 for_each_online_node(node) {
2112 struct kmem_cache_node *n = get_node(s, node);
2113 unsigned long nr_slabs;
2114 unsigned long nr_objs;
2115 unsigned long nr_free;
2116
2117 if (!n)
2118 continue;
2119
2120 nr_free = count_partial(n, count_free);
2121 nr_slabs = node_nr_slabs(n);
2122 nr_objs = node_nr_objs(n);
2123
2124 printk(KERN_WARNING
2125 " node %d: slabs: %ld, objs: %ld, free: %ld\n",
2126 node, nr_slabs, nr_objs, nr_free);
2127 }
2128}
2129
2130static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2131 int node, struct kmem_cache_cpu **pc)
2132{
2133 void *object;
2134 struct kmem_cache_cpu *c;
2135 struct page *page = new_slab(s, flags, node);
2136
2137 if (page) {
2138 c = __this_cpu_ptr(s->cpu_slab);
2139 if (c->page)
2140 flush_slab(s, c);
2141
2142 /*
2143 * No other reference to the page yet so we can
2144 * muck around with it freely without cmpxchg
2145 */
2146 object = page->freelist;
2147 page->freelist = NULL;
2148
2149 stat(s, ALLOC_SLAB);
2150 c->node = page_to_nid(page);
2151 c->page = page;
2152 *pc = c;
2153 } else
2154 object = NULL;
2155
2156 return object;
2157}
2158
2159/*
2160 * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
2161 * or deactivate the page.
2162 *
2163 * The page is still frozen if the return value is not NULL.
2164 *
2165 * If this function returns NULL then the page has been unfrozen.
2166 */
2167static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2168{
2169 struct page new;
2170 unsigned long counters;
2171 void *freelist;
2172
2173 do {
2174 freelist = page->freelist;
2175 counters = page->counters;
2176 new.counters = counters;
2177 VM_BUG_ON(!new.frozen);
2178
2179 new.inuse = page->objects;
2180 new.frozen = freelist != NULL;
2181
2182 } while (!cmpxchg_double_slab(s, page,
2183 freelist, counters,
2184 NULL, new.counters,
2185 "get_freelist"));
2186
2187 return freelist;
2188}
2189
2190/*
2191 * Slow path. The lockless freelist is empty or we need to perform
2192 * debugging duties.
2193 *
2194 * Processing is still very fast if new objects have been freed to the
2195 * regular freelist. In that case we simply take over the regular freelist
2196 * as the lockless freelist and zap the regular freelist.
2197 *
2198 * If that is not working then we fall back to the partial lists. We take the
2199 * first element of the freelist as the object to allocate now and move the
2200 * rest of the freelist to the lockless freelist.
2201 *
2202 * And if we were unable to get a new slab from the partial slab lists then
2203 * we need to allocate a new slab. This is the slowest path since it involves
2204 * a call to the page allocator and the setup of a new slab.
2205 */
2206static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2207 unsigned long addr, struct kmem_cache_cpu *c)
2208{
2209 void **object;
2210 unsigned long flags;
2211
2212 local_irq_save(flags);
2213#ifdef CONFIG_PREEMPT
2214 /*
2215 * We may have been preempted and rescheduled on a different
2216 * cpu before disabling interrupts. Need to reload cpu area
2217 * pointer.
2218 */
2219 c = this_cpu_ptr(s->cpu_slab);
2220#endif
2221
2222 if (!c->page)
2223 goto new_slab;
2224redo:
2225 if (unlikely(!node_match(c, node))) {
2226 stat(s, ALLOC_NODE_MISMATCH);
2227 deactivate_slab(s, c);
2228 goto new_slab;
2229 }
2230
2231 /* must check again c->freelist in case of cpu migration or IRQ */
2232 object = c->freelist;
2233 if (object)
2234 goto load_freelist;
2235
2236 stat(s, ALLOC_SLOWPATH);
2237
2238 object = get_freelist(s, c->page);
2239
2240 if (!object) {
2241 c->page = NULL;
2242 stat(s, DEACTIVATE_BYPASS);
2243 goto new_slab;
2244 }
2245
2246 stat(s, ALLOC_REFILL);
2247
2248load_freelist:
2249 c->freelist = get_freepointer(s, object);
2250 c->tid = next_tid(c->tid);
2251 local_irq_restore(flags);
2252 return object;
2253
2254new_slab:
2255
2256 if (c->partial) {
2257 c->page = c->partial;
2258 c->partial = c->page->next;
2259 c->node = page_to_nid(c->page);
2260 stat(s, CPU_PARTIAL_ALLOC);
2261 c->freelist = NULL;
2262 goto redo;
2263 }
2264
2265 /* Then do expensive stuff like retrieving pages from the partial lists */
2266 object = get_partial(s, gfpflags, node, c);
2267
2268 if (unlikely(!object)) {
2269
2270 object = new_slab_objects(s, gfpflags, node, &c);
2271
2272 if (unlikely(!object)) {
2273 if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2274 slab_out_of_memory(s, gfpflags, node);
2275
2276 local_irq_restore(flags);
2277 return NULL;
2278 }
2279 }
2280
2281 if (likely(!kmem_cache_debug(s)))
2282 goto load_freelist;
2283
2284 /* Only entered in the debug case */
2285 if (!alloc_debug_processing(s, c->page, object, addr))
2286 goto new_slab; /* Slab failed checks. Next slab needed */
2287
2288 c->freelist = get_freepointer(s, object);
2289 deactivate_slab(s, c);
2290 c->node = NUMA_NO_NODE;
2291 local_irq_restore(flags);
2292 return object;
2293}
2294
2295/*
2296 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2297 * have the fastpath folded into their functions. So no function call
2298 * overhead for requests that can be satisfied on the fastpath.
2299 *
2300 * The fastpath works by first checking if the lockless freelist can be used.
2301 * If not then __slab_alloc is called for slow processing.
2302 *
2303 * Otherwise we can simply pick the next object from the lockless free list.
2304 */
2305static __always_inline void *slab_alloc(struct kmem_cache *s,
2306 gfp_t gfpflags, int node, unsigned long addr)
2307{
2308 void **object;
2309 struct kmem_cache_cpu *c;
2310 unsigned long tid;
2311
2312 if (slab_pre_alloc_hook(s, gfpflags))
2313 return NULL;
2314
2315redo:
2316
2317 /*
2318 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2319 * enabled. We may switch back and forth between cpus while
2320 * reading from one cpu area. That does not matter as long
2321 * as we end up on the original cpu again when doing the cmpxchg.
2322 */
2323 c = __this_cpu_ptr(s->cpu_slab);
2324
2325 /*
2326 * The transaction ids are globally unique per cpu and per operation on
2327 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2328 * occurs on the right processor and that there was no operation on the
2329 * linked list in between.
2330 */
2331 tid = c->tid;
2332 barrier();
2333
2334 object = c->freelist;
2335 if (unlikely(!object || !node_match(c, node)))
2336
2337 object = __slab_alloc(s, gfpflags, node, addr, c);
2338
2339 else {
2340 void *next_object = get_freepointer_safe(s, object);
2341
2342 /*
2343 * The cmpxchg will only match if there was no additional
2344 * operation and if we are on the right processor.
2345 *
2346 * The cmpxchg does the following atomically (without lock semantics!)
2347 * 1. Relocate first pointer to the current per cpu area.
2348 * 2. Verify that tid and freelist have not been changed
2349 * 3. If they were not changed replace tid and freelist
2350 *
2351 * Since this is without lock semantics the protection is only against
2352 * code executing on this cpu *not* from access by other cpus.
2353 */
2354 if (unlikely(!this_cpu_cmpxchg_double(
2355 s->cpu_slab->freelist, s->cpu_slab->tid,
2356 object, tid,
2357 next_object, next_tid(tid)))) {
2358
2359 note_cmpxchg_failure("slab_alloc", s, tid);
2360 goto redo;
2361 }
2362 prefetch_freepointer(s, next_object);
2363 stat(s, ALLOC_FASTPATH);
2364 }
2365
2366 if (unlikely(gfpflags & __GFP_ZERO) && object)
2367 memset(object, 0, s->objsize);
2368
2369 slab_post_alloc_hook(s, gfpflags, object);
2370
2371 return object;
2372}
2373
2374void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2375{
2376 void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
2377
2378 trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
2379
2380 return ret;
2381}
2382EXPORT_SYMBOL(kmem_cache_alloc);
2383
2384#ifdef CONFIG_TRACING
2385void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2386{
2387 void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
2388 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2389 return ret;
2390}
2391EXPORT_SYMBOL(kmem_cache_alloc_trace);
2392
2393void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
2394{
2395 void *ret = kmalloc_order(size, flags, order);
2396 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
2397 return ret;
2398}
2399EXPORT_SYMBOL(kmalloc_order_trace);
2400#endif
2401
2402#ifdef CONFIG_NUMA
2403void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2404{
2405 void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
2406
2407 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2408 s->objsize, s->size, gfpflags, node);
2409
2410 return ret;
2411}
2412EXPORT_SYMBOL(kmem_cache_alloc_node);
2413
2414#ifdef CONFIG_TRACING
2415void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2416 gfp_t gfpflags,
2417 int node, size_t size)
2418{
2419 void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
2420
2421 trace_kmalloc_node(_RET_IP_, ret,
2422 size, s->size, gfpflags, node);
2423 return ret;
2424}
2425EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2426#endif
2427#endif
2428
2429/*
2430 * Slow patch handling. This may still be called frequently since objects
2431 * have a longer lifetime than the cpu slabs in most processing loads.
2432 *
2433 * So we still attempt to reduce cache line usage. Just take the slab
2434 * lock and free the item. If there is no additional partial page
2435 * handling required then we can return immediately.
2436 */
2437static void __slab_free(struct kmem_cache *s, struct page *page,
2438 void *x, unsigned long addr)
2439{
2440 void *prior;
2441 void **object = (void *)x;
2442 int was_frozen;
2443 int inuse;
2444 struct page new;
2445 unsigned long counters;
2446 struct kmem_cache_node *n = NULL;
2447 unsigned long uninitialized_var(flags);
2448
2449 stat(s, FREE_SLOWPATH);
2450
2451 if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
2452 return;
2453
2454 do {
2455 prior = page->freelist;
2456 counters = page->counters;
2457 set_freepointer(s, object, prior);
2458 new.counters = counters;
2459 was_frozen = new.frozen;
2460 new.inuse--;
2461 if ((!new.inuse || !prior) && !was_frozen && !n) {
2462
2463 if (!kmem_cache_debug(s) && !prior)
2464
2465 /*
2466 * Slab was on no list before and will be partially empty
2467 * We can defer the list move and instead freeze it.
2468 */
2469 new.frozen = 1;
2470
2471 else { /* Needs to be taken off a list */
2472
2473 n = get_node(s, page_to_nid(page));
2474 /*
2475 * Speculatively acquire the list_lock.
2476 * If the cmpxchg does not succeed then we may
2477 * drop the list_lock without any processing.
2478 *
2479 * Otherwise the list_lock will synchronize with
2480 * other processors updating the list of slabs.
2481 */
2482 spin_lock_irqsave(&n->list_lock, flags);
2483
2484 }
2485 }
2486 inuse = new.inuse;
2487
2488 } while (!cmpxchg_double_slab(s, page,
2489 prior, counters,
2490 object, new.counters,
2491 "__slab_free"));
2492
2493 if (likely(!n)) {
2494
2495 /*
2496 * If we just froze the page then put it onto the
2497 * per cpu partial list.
2498 */
2499 if (new.frozen && !was_frozen) {
2500 put_cpu_partial(s, page, 1);
2501 stat(s, CPU_PARTIAL_FREE);
2502 }
2503 /*
2504 * The list lock was not taken therefore no list
2505 * activity can be necessary.
2506 */
2507 if (was_frozen)
2508 stat(s, FREE_FROZEN);
2509 return;
2510 }
2511
2512 /*
2513 * was_frozen may have been set after we acquired the list_lock in
2514 * an earlier loop. So we need to check it here again.
2515 */
2516 if (was_frozen)
2517 stat(s, FREE_FROZEN);
2518 else {
2519 if (unlikely(!inuse && n->nr_partial > s->min_partial))
2520 goto slab_empty;
2521
2522 /*
2523 * Objects left in the slab. If it was not on the partial list before
2524 * then add it.
2525 */
2526 if (unlikely(!prior)) {
2527 remove_full(s, page);
2528 add_partial(n, page, DEACTIVATE_TO_TAIL);
2529 stat(s, FREE_ADD_PARTIAL);
2530 }
2531 }
2532 spin_unlock_irqrestore(&n->list_lock, flags);
2533 return;
2534
2535slab_empty:
2536 if (prior) {
2537 /*
2538 * Slab on the partial list.
2539 */
2540 remove_partial(n, page);
2541 stat(s, FREE_REMOVE_PARTIAL);
2542 } else
2543 /* Slab must be on the full list */
2544 remove_full(s, page);
2545
2546 spin_unlock_irqrestore(&n->list_lock, flags);
2547 stat(s, FREE_SLAB);
2548 discard_slab(s, page);
2549}
2550
2551/*
2552 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2553 * can perform fastpath freeing without additional function calls.
2554 *
2555 * The fastpath is only possible if we are freeing to the current cpu slab
2556 * of this processor. This typically the case if we have just allocated
2557 * the item before.
2558 *
2559 * If fastpath is not possible then fall back to __slab_free where we deal
2560 * with all sorts of special processing.
2561 */
2562static __always_inline void slab_free(struct kmem_cache *s,
2563 struct page *page, void *x, unsigned long addr)
2564{
2565 void **object = (void *)x;
2566 struct kmem_cache_cpu *c;
2567 unsigned long tid;
2568
2569 slab_free_hook(s, x);
2570
2571redo:
2572 /*
2573 * Determine the currently cpus per cpu slab.
2574 * The cpu may change afterward. However that does not matter since
2575 * data is retrieved via this pointer. If we are on the same cpu
2576 * during the cmpxchg then the free will succedd.
2577 */
2578 c = __this_cpu_ptr(s->cpu_slab);
2579
2580 tid = c->tid;
2581 barrier();
2582
2583 if (likely(page == c->page)) {
2584 set_freepointer(s, object, c->freelist);
2585
2586 if (unlikely(!this_cpu_cmpxchg_double(
2587 s->cpu_slab->freelist, s->cpu_slab->tid,
2588 c->freelist, tid,
2589 object, next_tid(tid)))) {
2590
2591 note_cmpxchg_failure("slab_free", s, tid);
2592 goto redo;
2593 }
2594 stat(s, FREE_FASTPATH);
2595 } else
2596 __slab_free(s, page, x, addr);
2597
2598}
2599
2600void kmem_cache_free(struct kmem_cache *s, void *x)
2601{
2602 struct page *page;
2603
2604 page = virt_to_head_page(x);
2605
2606 slab_free(s, page, x, _RET_IP_);
2607
2608 trace_kmem_cache_free(_RET_IP_, x);
2609}
2610EXPORT_SYMBOL(kmem_cache_free);
2611
2612/*
2613 * Object placement in a slab is made very easy because we always start at
2614 * offset 0. If we tune the size of the object to the alignment then we can
2615 * get the required alignment by putting one properly sized object after
2616 * another.
2617 *
2618 * Notice that the allocation order determines the sizes of the per cpu
2619 * caches. Each processor has always one slab available for allocations.
2620 * Increasing the allocation order reduces the number of times that slabs
2621 * must be moved on and off the partial lists and is therefore a factor in
2622 * locking overhead.
2623 */
2624
2625/*
2626 * Mininum / Maximum order of slab pages. This influences locking overhead
2627 * and slab fragmentation. A higher order reduces the number of partial slabs
2628 * and increases the number of allocations possible without having to
2629 * take the list_lock.
2630 */
2631static int slub_min_order;
2632static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2633static int slub_min_objects;
2634
2635/*
2636 * Merge control. If this is set then no merging of slab caches will occur.
2637 * (Could be removed. This was introduced to pacify the merge skeptics.)
2638 */
2639static int slub_nomerge;
2640
2641/*
2642 * Calculate the order of allocation given an slab object size.
2643 *
2644 * The order of allocation has significant impact on performance and other
2645 * system components. Generally order 0 allocations should be preferred since
2646 * order 0 does not cause fragmentation in the page allocator. Larger objects
2647 * be problematic to put into order 0 slabs because there may be too much
2648 * unused space left. We go to a higher order if more than 1/16th of the slab
2649 * would be wasted.
2650 *
2651 * In order to reach satisfactory performance we must ensure that a minimum
2652 * number of objects is in one slab. Otherwise we may generate too much
2653 * activity on the partial lists which requires taking the list_lock. This is
2654 * less a concern for large slabs though which are rarely used.
2655 *
2656 * slub_max_order specifies the order where we begin to stop considering the
2657 * number of objects in a slab as critical. If we reach slub_max_order then
2658 * we try to keep the page order as low as possible. So we accept more waste
2659 * of space in favor of a small page order.
2660 *
2661 * Higher order allocations also allow the placement of more objects in a
2662 * slab and thereby reduce object handling overhead. If the user has
2663 * requested a higher mininum order then we start with that one instead of
2664 * the smallest order which will fit the object.
2665 */
2666static inline int slab_order(int size, int min_objects,
2667 int max_order, int fract_leftover, int reserved)
2668{
2669 int order;
2670 int rem;
2671 int min_order = slub_min_order;
2672
2673 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2674 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2675
2676 for (order = max(min_order,
2677 fls(min_objects * size - 1) - PAGE_SHIFT);
2678 order <= max_order; order++) {
2679
2680 unsigned long slab_size = PAGE_SIZE << order;
2681
2682 if (slab_size < min_objects * size + reserved)
2683 continue;
2684
2685 rem = (slab_size - reserved) % size;
2686
2687 if (rem <= slab_size / fract_leftover)
2688 break;
2689
2690 }
2691
2692 return order;
2693}
2694
2695static inline int calculate_order(int size, int reserved)
2696{
2697 int order;
2698 int min_objects;
2699 int fraction;
2700 int max_objects;
2701
2702 /*
2703 * Attempt to find best configuration for a slab. This
2704 * works by first attempting to generate a layout with
2705 * the best configuration and backing off gradually.
2706 *
2707 * First we reduce the acceptable waste in a slab. Then
2708 * we reduce the minimum objects required in a slab.
2709 */
2710 min_objects = slub_min_objects;
2711 if (!min_objects)
2712 min_objects = 4 * (fls(nr_cpu_ids) + 1);
2713 max_objects = order_objects(slub_max_order, size, reserved);
2714 min_objects = min(min_objects, max_objects);
2715
2716 while (min_objects > 1) {
2717 fraction = 16;
2718 while (fraction >= 4) {
2719 order = slab_order(size, min_objects,
2720 slub_max_order, fraction, reserved);
2721 if (order <= slub_max_order)
2722 return order;
2723 fraction /= 2;
2724 }
2725 min_objects--;
2726 }
2727
2728 /*
2729 * We were unable to place multiple objects in a slab. Now
2730 * lets see if we can place a single object there.
2731 */
2732 order = slab_order(size, 1, slub_max_order, 1, reserved);
2733 if (order <= slub_max_order)
2734 return order;
2735
2736 /*
2737 * Doh this slab cannot be placed using slub_max_order.
2738 */
2739 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2740 if (order < MAX_ORDER)
2741 return order;
2742 return -ENOSYS;
2743}
2744
2745/*
2746 * Figure out what the alignment of the objects will be.
2747 */
2748static unsigned long calculate_alignment(unsigned long flags,
2749 unsigned long align, unsigned long size)
2750{
2751 /*
2752 * If the user wants hardware cache aligned objects then follow that
2753 * suggestion if the object is sufficiently large.
2754 *
2755 * The hardware cache alignment cannot override the specified
2756 * alignment though. If that is greater then use it.
2757 */
2758 if (flags & SLAB_HWCACHE_ALIGN) {
2759 unsigned long ralign = cache_line_size();
2760 while (size <= ralign / 2)
2761 ralign /= 2;
2762 align = max(align, ralign);
2763 }
2764
2765 if (align < ARCH_SLAB_MINALIGN)
2766 align = ARCH_SLAB_MINALIGN;
2767
2768 return ALIGN(align, sizeof(void *));
2769}
2770
2771static void
2772init_kmem_cache_node(struct kmem_cache_node *n)
2773{
2774 n->nr_partial = 0;
2775 spin_lock_init(&n->list_lock);
2776 INIT_LIST_HEAD(&n->partial);
2777#ifdef CONFIG_SLUB_DEBUG
2778 atomic_long_set(&n->nr_slabs, 0);
2779 atomic_long_set(&n->total_objects, 0);
2780 INIT_LIST_HEAD(&n->full);
2781#endif
2782}
2783
2784static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2785{
2786 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2787 SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
2788
2789 /*
2790 * Must align to double word boundary for the double cmpxchg
2791 * instructions to work; see __pcpu_double_call_return_bool().
2792 */
2793 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2794 2 * sizeof(void *));
2795
2796 if (!s->cpu_slab)
2797 return 0;
2798
2799 init_kmem_cache_cpus(s);
2800
2801 return 1;
2802}
2803
2804static struct kmem_cache *kmem_cache_node;
2805
2806/*
2807 * No kmalloc_node yet so do it by hand. We know that this is the first
2808 * slab on the node for this slabcache. There are no concurrent accesses
2809 * possible.
2810 *
2811 * Note that this function only works on the kmalloc_node_cache
2812 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2813 * memory on a fresh node that has no slab structures yet.
2814 */
2815static void early_kmem_cache_node_alloc(int node)
2816{
2817 struct page *page;
2818 struct kmem_cache_node *n;
2819
2820 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2821
2822 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2823
2824 BUG_ON(!page);
2825 if (page_to_nid(page) != node) {
2826 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2827 "node %d\n", node);
2828 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2829 "in order to be able to continue\n");
2830 }
2831
2832 n = page->freelist;
2833 BUG_ON(!n);
2834 page->freelist = get_freepointer(kmem_cache_node, n);
2835 page->inuse = 1;
2836 page->frozen = 0;
2837 kmem_cache_node->node[node] = n;
2838#ifdef CONFIG_SLUB_DEBUG
2839 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2840 init_tracking(kmem_cache_node, n);
2841#endif
2842 init_kmem_cache_node(n);
2843 inc_slabs_node(kmem_cache_node, node, page->objects);
2844
2845 add_partial(n, page, DEACTIVATE_TO_HEAD);
2846}
2847
2848static void free_kmem_cache_nodes(struct kmem_cache *s)
2849{
2850 int node;
2851
2852 for_each_node_state(node, N_NORMAL_MEMORY) {
2853 struct kmem_cache_node *n = s->node[node];
2854
2855 if (n)
2856 kmem_cache_free(kmem_cache_node, n);
2857
2858 s->node[node] = NULL;
2859 }
2860}
2861
2862static int init_kmem_cache_nodes(struct kmem_cache *s)
2863{
2864 int node;
2865
2866 for_each_node_state(node, N_NORMAL_MEMORY) {
2867 struct kmem_cache_node *n;
2868
2869 if (slab_state == DOWN) {
2870 early_kmem_cache_node_alloc(node);
2871 continue;
2872 }
2873 n = kmem_cache_alloc_node(kmem_cache_node,
2874 GFP_KERNEL, node);
2875
2876 if (!n) {
2877 free_kmem_cache_nodes(s);
2878 return 0;
2879 }
2880
2881 s->node[node] = n;
2882 init_kmem_cache_node(n);
2883 }
2884 return 1;
2885}
2886
2887static void set_min_partial(struct kmem_cache *s, unsigned long min)
2888{
2889 if (min < MIN_PARTIAL)
2890 min = MIN_PARTIAL;
2891 else if (min > MAX_PARTIAL)
2892 min = MAX_PARTIAL;
2893 s->min_partial = min;
2894}
2895
2896/*
2897 * calculate_sizes() determines the order and the distribution of data within
2898 * a slab object.
2899 */
2900static int calculate_sizes(struct kmem_cache *s, int forced_order)
2901{
2902 unsigned long flags = s->flags;
2903 unsigned long size = s->objsize;
2904 unsigned long align = s->align;
2905 int order;
2906
2907 /*
2908 * Round up object size to the next word boundary. We can only
2909 * place the free pointer at word boundaries and this determines
2910 * the possible location of the free pointer.
2911 */
2912 size = ALIGN(size, sizeof(void *));
2913
2914#ifdef CONFIG_SLUB_DEBUG
2915 /*
2916 * Determine if we can poison the object itself. If the user of
2917 * the slab may touch the object after free or before allocation
2918 * then we should never poison the object itself.
2919 */
2920 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2921 !s->ctor)
2922 s->flags |= __OBJECT_POISON;
2923 else
2924 s->flags &= ~__OBJECT_POISON;
2925
2926
2927 /*
2928 * If we are Redzoning then check if there is some space between the
2929 * end of the object and the free pointer. If not then add an
2930 * additional word to have some bytes to store Redzone information.
2931 */
2932 if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2933 size += sizeof(void *);
2934#endif
2935
2936 /*
2937 * With that we have determined the number of bytes in actual use
2938 * by the object. This is the potential offset to the free pointer.
2939 */
2940 s->inuse = size;
2941
2942 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2943 s->ctor)) {
2944 /*
2945 * Relocate free pointer after the object if it is not
2946 * permitted to overwrite the first word of the object on
2947 * kmem_cache_free.
2948 *
2949 * This is the case if we do RCU, have a constructor or
2950 * destructor or are poisoning the objects.
2951 */
2952 s->offset = size;
2953 size += sizeof(void *);
2954 }
2955
2956#ifdef CONFIG_SLUB_DEBUG
2957 if (flags & SLAB_STORE_USER)
2958 /*
2959 * Need to store information about allocs and frees after
2960 * the object.
2961 */
2962 size += 2 * sizeof(struct track);
2963
2964 if (flags & SLAB_RED_ZONE)
2965 /*
2966 * Add some empty padding so that we can catch
2967 * overwrites from earlier objects rather than let
2968 * tracking information or the free pointer be
2969 * corrupted if a user writes before the start
2970 * of the object.
2971 */
2972 size += sizeof(void *);
2973#endif
2974
2975 /*
2976 * Determine the alignment based on various parameters that the
2977 * user specified and the dynamic determination of cache line size
2978 * on bootup.
2979 */
2980 align = calculate_alignment(flags, align, s->objsize);
2981 s->align = align;
2982
2983 /*
2984 * SLUB stores one object immediately after another beginning from
2985 * offset 0. In order to align the objects we have to simply size
2986 * each object to conform to the alignment.
2987 */
2988 size = ALIGN(size, align);
2989 s->size = size;
2990 if (forced_order >= 0)
2991 order = forced_order;
2992 else
2993 order = calculate_order(size, s->reserved);
2994
2995 if (order < 0)
2996 return 0;
2997
2998 s->allocflags = 0;
2999 if (order)
3000 s->allocflags |= __GFP_COMP;
3001
3002 if (s->flags & SLAB_CACHE_DMA)
3003 s->allocflags |= SLUB_DMA;
3004
3005 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3006 s->allocflags |= __GFP_RECLAIMABLE;
3007
3008 /*
3009 * Determine the number of objects per slab
3010 */
3011 s->oo = oo_make(order, size, s->reserved);
3012 s->min = oo_make(get_order(size), size, s->reserved);
3013 if (oo_objects(s->oo) > oo_objects(s->max))
3014 s->max = s->oo;
3015
3016 return !!oo_objects(s->oo);
3017
3018}
3019
3020static int kmem_cache_open(struct kmem_cache *s,
3021 const char *name, size_t size,
3022 size_t align, unsigned long flags,
3023 void (*ctor)(void *))
3024{
3025 memset(s, 0, kmem_size);
3026 s->name = name;
3027 s->ctor = ctor;
3028 s->objsize = size;
3029 s->align = align;
3030 s->flags = kmem_cache_flags(size, flags, name, ctor);
3031 s->reserved = 0;
3032
3033 if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3034 s->reserved = sizeof(struct rcu_head);
3035
3036 if (!calculate_sizes(s, -1))
3037 goto error;
3038 if (disable_higher_order_debug) {
3039 /*
3040 * Disable debugging flags that store metadata if the min slab
3041 * order increased.
3042 */
3043 if (get_order(s->size) > get_order(s->objsize)) {
3044 s->flags &= ~DEBUG_METADATA_FLAGS;
3045 s->offset = 0;
3046 if (!calculate_sizes(s, -1))
3047 goto error;
3048 }
3049 }
3050
3051#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3052 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3053 if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
3054 /* Enable fast mode */
3055 s->flags |= __CMPXCHG_DOUBLE;
3056#endif
3057
3058 /*
3059 * The larger the object size is, the more pages we want on the partial
3060 * list to avoid pounding the page allocator excessively.
3061 */
3062 set_min_partial(s, ilog2(s->size) / 2);
3063
3064 /*
3065 * cpu_partial determined the maximum number of objects kept in the
3066 * per cpu partial lists of a processor.
3067 *
3068 * Per cpu partial lists mainly contain slabs that just have one
3069 * object freed. If they are used for allocation then they can be
3070 * filled up again with minimal effort. The slab will never hit the
3071 * per node partial lists and therefore no locking will be required.
3072 *
3073 * This setting also determines
3074 *
3075 * A) The number of objects from per cpu partial slabs dumped to the
3076 * per node list when we reach the limit.
3077 * B) The number of objects in cpu partial slabs to extract from the
3078 * per node list when we run out of per cpu objects. We only fetch 50%
3079 * to keep some capacity around for frees.
3080 */
3081 if (kmem_cache_debug(s))
3082 s->cpu_partial = 0;
3083 else if (s->size >= PAGE_SIZE)
3084 s->cpu_partial = 2;
3085 else if (s->size >= 1024)
3086 s->cpu_partial = 6;
3087 else if (s->size >= 256)
3088 s->cpu_partial = 13;
3089 else
3090 s->cpu_partial = 30;
3091
3092 s->refcount = 1;
3093#ifdef CONFIG_NUMA
3094 s->remote_node_defrag_ratio = 1000;
3095#endif
3096 if (!init_kmem_cache_nodes(s))
3097 goto error;
3098
3099 if (alloc_kmem_cache_cpus(s))
3100 return 1;
3101
3102 free_kmem_cache_nodes(s);
3103error:
3104 if (flags & SLAB_PANIC)
3105 panic("Cannot create slab %s size=%lu realsize=%u "
3106 "order=%u offset=%u flags=%lx\n",
3107 s->name, (unsigned long)size, s->size, oo_order(s->oo),
3108 s->offset, flags);
3109 return 0;
3110}
3111
3112/*
3113 * Determine the size of a slab object
3114 */
3115unsigned int kmem_cache_size(struct kmem_cache *s)
3116{
3117 return s->objsize;
3118}
3119EXPORT_SYMBOL(kmem_cache_size);
3120
3121static void list_slab_objects(struct kmem_cache *s, struct page *page,
3122 const char *text)
3123{
3124#ifdef CONFIG_SLUB_DEBUG
3125 void *addr = page_address(page);
3126 void *p;
3127 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3128 sizeof(long), GFP_ATOMIC);
3129 if (!map)
3130 return;
3131 slab_err(s, page, "%s", text);
3132 slab_lock(page);
3133
3134 get_map(s, page, map);
3135 for_each_object(p, s, addr, page->objects) {
3136
3137 if (!test_bit(slab_index(p, s, addr), map)) {
3138 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
3139 p, p - addr);
3140 print_tracking(s, p);
3141 }
3142 }
3143 slab_unlock(page);
3144 kfree(map);
3145#endif
3146}
3147
3148/*
3149 * Attempt to free all partial slabs on a node.
3150 * This is called from kmem_cache_close(). We must be the last thread
3151 * using the cache and therefore we do not need to lock anymore.
3152 */
3153static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3154{
3155 struct page *page, *h;
3156
3157 list_for_each_entry_safe(page, h, &n->partial, lru) {
3158 if (!page->inuse) {
3159 remove_partial(n, page);
3160 discard_slab(s, page);
3161 } else {
3162 list_slab_objects(s, page,
3163 "Objects remaining on kmem_cache_close()");
3164 }
3165 }
3166}
3167
3168/*
3169 * Release all resources used by a slab cache.
3170 */
3171static inline int kmem_cache_close(struct kmem_cache *s)
3172{
3173 int node;
3174
3175 flush_all(s);
3176 free_percpu(s->cpu_slab);
3177 /* Attempt to free all objects */
3178 for_each_node_state(node, N_NORMAL_MEMORY) {
3179 struct kmem_cache_node *n = get_node(s, node);
3180
3181 free_partial(s, n);
3182 if (n->nr_partial || slabs_node(s, node))
3183 return 1;
3184 }
3185 free_kmem_cache_nodes(s);
3186 return 0;
3187}
3188
3189/*
3190 * Close a cache and release the kmem_cache structure
3191 * (must be used for caches created using kmem_cache_create)
3192 */
3193void kmem_cache_destroy(struct kmem_cache *s)
3194{
3195 down_write(&slub_lock);
3196 s->refcount--;
3197 if (!s->refcount) {
3198 list_del(&s->list);
3199 up_write(&slub_lock);
3200 if (kmem_cache_close(s)) {
3201 printk(KERN_ERR "SLUB %s: %s called for cache that "
3202 "still has objects.\n", s->name, __func__);
3203 dump_stack();
3204 }
3205 if (s->flags & SLAB_DESTROY_BY_RCU)
3206 rcu_barrier();
3207 sysfs_slab_remove(s);
3208 } else
3209 up_write(&slub_lock);
3210}
3211EXPORT_SYMBOL(kmem_cache_destroy);
3212
3213/********************************************************************
3214 * Kmalloc subsystem
3215 *******************************************************************/
3216
3217struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
3218EXPORT_SYMBOL(kmalloc_caches);
3219
3220static struct kmem_cache *kmem_cache;
3221
3222#ifdef CONFIG_ZONE_DMA
3223static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
3224#endif
3225
3226static int __init setup_slub_min_order(char *str)
3227{
3228 get_option(&str, &slub_min_order);
3229
3230 return 1;
3231}
3232
3233__setup("slub_min_order=", setup_slub_min_order);
3234
3235static int __init setup_slub_max_order(char *str)
3236{
3237 get_option(&str, &slub_max_order);
3238 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3239
3240 return 1;
3241}
3242
3243__setup("slub_max_order=", setup_slub_max_order);
3244
3245static int __init setup_slub_min_objects(char *str)
3246{
3247 get_option(&str, &slub_min_objects);
3248
3249 return 1;
3250}
3251
3252__setup("slub_min_objects=", setup_slub_min_objects);
3253
3254static int __init setup_slub_nomerge(char *str)
3255{
3256 slub_nomerge = 1;
3257 return 1;
3258}
3259
3260__setup("slub_nomerge", setup_slub_nomerge);
3261
3262static struct kmem_cache *__init create_kmalloc_cache(const char *name,
3263 int size, unsigned int flags)
3264{
3265 struct kmem_cache *s;
3266
3267 s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3268
3269 /*
3270 * This function is called with IRQs disabled during early-boot on
3271 * single CPU so there's no need to take slub_lock here.
3272 */
3273 if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
3274 flags, NULL))
3275 goto panic;
3276
3277 list_add(&s->list, &slab_caches);
3278 return s;
3279
3280panic:
3281 panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
3282 return NULL;
3283}
3284
3285/*
3286 * Conversion table for small slabs sizes / 8 to the index in the
3287 * kmalloc array. This is necessary for slabs < 192 since we have non power
3288 * of two cache sizes there. The size of larger slabs can be determined using
3289 * fls.
3290 */
3291static s8 size_index[24] = {
3292 3, /* 8 */
3293 4, /* 16 */
3294 5, /* 24 */
3295 5, /* 32 */
3296 6, /* 40 */
3297 6, /* 48 */
3298 6, /* 56 */
3299 6, /* 64 */
3300 1, /* 72 */
3301 1, /* 80 */
3302 1, /* 88 */
3303 1, /* 96 */
3304 7, /* 104 */
3305 7, /* 112 */
3306 7, /* 120 */
3307 7, /* 128 */
3308 2, /* 136 */
3309 2, /* 144 */
3310 2, /* 152 */
3311 2, /* 160 */
3312 2, /* 168 */
3313 2, /* 176 */
3314 2, /* 184 */
3315 2 /* 192 */
3316};
3317
3318static inline int size_index_elem(size_t bytes)
3319{
3320 return (bytes - 1) / 8;
3321}
3322
3323static struct kmem_cache *get_slab(size_t size, gfp_t flags)
3324{
3325 int index;
3326
3327 if (size <= 192) {
3328 if (!size)
3329 return ZERO_SIZE_PTR;
3330
3331 index = size_index[size_index_elem(size)];
3332 } else
3333 index = fls(size - 1);
3334
3335#ifdef CONFIG_ZONE_DMA
3336 if (unlikely((flags & SLUB_DMA)))
3337 return kmalloc_dma_caches[index];
3338
3339#endif
3340 return kmalloc_caches[index];
3341}
3342
3343void *__kmalloc(size_t size, gfp_t flags)
3344{
3345 struct kmem_cache *s;
3346 void *ret;
3347
3348 if (unlikely(size > SLUB_MAX_SIZE))
3349 return kmalloc_large(size, flags);
3350
3351 s = get_slab(size, flags);
3352
3353 if (unlikely(ZERO_OR_NULL_PTR(s)))
3354 return s;
3355
3356 ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
3357
3358 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3359
3360 return ret;
3361}
3362EXPORT_SYMBOL(__kmalloc);
3363
3364#ifdef CONFIG_NUMA
3365static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3366{
3367 struct page *page;
3368 void *ptr = NULL;
3369
3370 flags |= __GFP_COMP | __GFP_NOTRACK;
3371 page = alloc_pages_node(node, flags, get_order(size));
3372 if (page)
3373 ptr = page_address(page);
3374
3375 kmemleak_alloc(ptr, size, 1, flags);
3376 return ptr;
3377}
3378
3379void *__kmalloc_node(size_t size, gfp_t flags, int node)
3380{
3381 struct kmem_cache *s;
3382 void *ret;
3383
3384 if (unlikely(size > SLUB_MAX_SIZE)) {
3385 ret = kmalloc_large_node(size, flags, node);
3386
3387 trace_kmalloc_node(_RET_IP_, ret,
3388 size, PAGE_SIZE << get_order(size),
3389 flags, node);
3390
3391 return ret;
3392 }
3393
3394 s = get_slab(size, flags);
3395
3396 if (unlikely(ZERO_OR_NULL_PTR(s)))
3397 return s;
3398
3399 ret = slab_alloc(s, flags, node, _RET_IP_);
3400
3401 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3402
3403 return ret;
3404}
3405EXPORT_SYMBOL(__kmalloc_node);
3406#endif
3407
3408size_t ksize(const void *object)
3409{
3410 struct page *page;
3411
3412 if (unlikely(object == ZERO_SIZE_PTR))
3413 return 0;
3414
3415 page = virt_to_head_page(object);
3416
3417 if (unlikely(!PageSlab(page))) {
3418 WARN_ON(!PageCompound(page));
3419 return PAGE_SIZE << compound_order(page);
3420 }
3421
3422 return slab_ksize(page->slab);
3423}
3424EXPORT_SYMBOL(ksize);
3425
3426#ifdef CONFIG_SLUB_DEBUG
3427bool verify_mem_not_deleted(const void *x)
3428{
3429 struct page *page;
3430 void *object = (void *)x;
3431 unsigned long flags;
3432 bool rv;
3433
3434 if (unlikely(ZERO_OR_NULL_PTR(x)))
3435 return false;
3436
3437 local_irq_save(flags);
3438
3439 page = virt_to_head_page(x);
3440 if (unlikely(!PageSlab(page))) {
3441 /* maybe it was from stack? */
3442 rv = true;
3443 goto out_unlock;
3444 }
3445
3446 slab_lock(page);
3447 if (on_freelist(page->slab, page, object)) {
3448 object_err(page->slab, page, object, "Object is on free-list");
3449 rv = false;
3450 } else {
3451 rv = true;
3452 }
3453 slab_unlock(page);
3454
3455out_unlock:
3456 local_irq_restore(flags);
3457 return rv;
3458}
3459EXPORT_SYMBOL(verify_mem_not_deleted);
3460#endif
3461
3462void kfree(const void *x)
3463{
3464 struct page *page;
3465 void *object = (void *)x;
3466
3467 trace_kfree(_RET_IP_, x);
3468
3469 if (unlikely(ZERO_OR_NULL_PTR(x)))
3470 return;
3471
3472 page = virt_to_head_page(x);
3473 if (unlikely(!PageSlab(page))) {
3474 BUG_ON(!PageCompound(page));
3475 kmemleak_free(x);
3476 put_page(page);
3477 return;
3478 }
3479 slab_free(page->slab, page, object, _RET_IP_);
3480}
3481EXPORT_SYMBOL(kfree);
3482
3483/*
3484 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3485 * the remaining slabs by the number of items in use. The slabs with the
3486 * most items in use come first. New allocations will then fill those up
3487 * and thus they can be removed from the partial lists.
3488 *
3489 * The slabs with the least items are placed last. This results in them
3490 * being allocated from last increasing the chance that the last objects
3491 * are freed in them.
3492 */
3493int kmem_cache_shrink(struct kmem_cache *s)
3494{
3495 int node;
3496 int i;
3497 struct kmem_cache_node *n;
3498 struct page *page;
3499 struct page *t;
3500 int objects = oo_objects(s->max);
3501 struct list_head *slabs_by_inuse =
3502 kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3503 unsigned long flags;
3504
3505 if (!slabs_by_inuse)
3506 return -ENOMEM;
3507
3508 flush_all(s);
3509 for_each_node_state(node, N_NORMAL_MEMORY) {
3510 n = get_node(s, node);
3511
3512 if (!n->nr_partial)
3513 continue;
3514
3515 for (i = 0; i < objects; i++)
3516 INIT_LIST_HEAD(slabs_by_inuse + i);
3517
3518 spin_lock_irqsave(&n->list_lock, flags);
3519
3520 /*
3521 * Build lists indexed by the items in use in each slab.
3522 *
3523 * Note that concurrent frees may occur while we hold the
3524 * list_lock. page->inuse here is the upper limit.
3525 */
3526 list_for_each_entry_safe(page, t, &n->partial, lru) {
3527 list_move(&page->lru, slabs_by_inuse + page->inuse);
3528 if (!page->inuse)
3529 n->nr_partial--;
3530 }
3531
3532 /*
3533 * Rebuild the partial list with the slabs filled up most
3534 * first and the least used slabs at the end.
3535 */
3536 for (i = objects - 1; i > 0; i--)
3537 list_splice(slabs_by_inuse + i, n->partial.prev);
3538
3539 spin_unlock_irqrestore(&n->list_lock, flags);
3540
3541 /* Release empty slabs */
3542 list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
3543 discard_slab(s, page);
3544 }
3545
3546 kfree(slabs_by_inuse);
3547 return 0;
3548}
3549EXPORT_SYMBOL(kmem_cache_shrink);
3550
3551#if defined(CONFIG_MEMORY_HOTPLUG)
3552static int slab_mem_going_offline_callback(void *arg)
3553{
3554 struct kmem_cache *s;
3555
3556 down_read(&slub_lock);
3557 list_for_each_entry(s, &slab_caches, list)
3558 kmem_cache_shrink(s);
3559 up_read(&slub_lock);
3560
3561 return 0;
3562}
3563
3564static void slab_mem_offline_callback(void *arg)
3565{
3566 struct kmem_cache_node *n;
3567 struct kmem_cache *s;
3568 struct memory_notify *marg = arg;
3569 int offline_node;
3570
3571 offline_node = marg->status_change_nid;
3572
3573 /*
3574 * If the node still has available memory. we need kmem_cache_node
3575 * for it yet.
3576 */
3577 if (offline_node < 0)
3578 return;
3579
3580 down_read(&slub_lock);
3581 list_for_each_entry(s, &slab_caches, list) {
3582 n = get_node(s, offline_node);
3583 if (n) {
3584 /*
3585 * if n->nr_slabs > 0, slabs still exist on the node
3586 * that is going down. We were unable to free them,
3587 * and offline_pages() function shouldn't call this
3588 * callback. So, we must fail.
3589 */
3590 BUG_ON(slabs_node(s, offline_node));
3591
3592 s->node[offline_node] = NULL;
3593 kmem_cache_free(kmem_cache_node, n);
3594 }
3595 }
3596 up_read(&slub_lock);
3597}
3598
3599static int slab_mem_going_online_callback(void *arg)
3600{
3601 struct kmem_cache_node *n;
3602 struct kmem_cache *s;
3603 struct memory_notify *marg = arg;
3604 int nid = marg->status_change_nid;
3605 int ret = 0;
3606
3607 /*
3608 * If the node's memory is already available, then kmem_cache_node is
3609 * already created. Nothing to do.
3610 */
3611 if (nid < 0)
3612 return 0;
3613
3614 /*
3615 * We are bringing a node online. No memory is available yet. We must
3616 * allocate a kmem_cache_node structure in order to bring the node
3617 * online.
3618 */
3619 down_read(&slub_lock);
3620 list_for_each_entry(s, &slab_caches, list) {
3621 /*
3622 * XXX: kmem_cache_alloc_node will fallback to other nodes
3623 * since memory is not yet available from the node that
3624 * is brought up.
3625 */
3626 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3627 if (!n) {
3628 ret = -ENOMEM;
3629 goto out;
3630 }
3631 init_kmem_cache_node(n);
3632 s->node[nid] = n;
3633 }
3634out:
3635 up_read(&slub_lock);
3636 return ret;
3637}
3638
3639static int slab_memory_callback(struct notifier_block *self,
3640 unsigned long action, void *arg)
3641{
3642 int ret = 0;
3643
3644 switch (action) {
3645 case MEM_GOING_ONLINE:
3646 ret = slab_mem_going_online_callback(arg);
3647 break;
3648 case MEM_GOING_OFFLINE:
3649 ret = slab_mem_going_offline_callback(arg);
3650 break;
3651 case MEM_OFFLINE:
3652 case MEM_CANCEL_ONLINE:
3653 slab_mem_offline_callback(arg);
3654 break;
3655 case MEM_ONLINE:
3656 case MEM_CANCEL_OFFLINE:
3657 break;
3658 }
3659 if (ret)
3660 ret = notifier_from_errno(ret);
3661 else
3662 ret = NOTIFY_OK;
3663 return ret;
3664}
3665
3666#endif /* CONFIG_MEMORY_HOTPLUG */
3667
3668/********************************************************************
3669 * Basic setup of slabs
3670 *******************************************************************/
3671
3672/*
3673 * Used for early kmem_cache structures that were allocated using
3674 * the page allocator
3675 */
3676
3677static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s)
3678{
3679 int node;
3680
3681 list_add(&s->list, &slab_caches);
3682 s->refcount = -1;
3683
3684 for_each_node_state(node, N_NORMAL_MEMORY) {
3685 struct kmem_cache_node *n = get_node(s, node);
3686 struct page *p;
3687
3688 if (n) {
3689 list_for_each_entry(p, &n->partial, lru)
3690 p->slab = s;
3691
3692#ifdef CONFIG_SLUB_DEBUG
3693 list_for_each_entry(p, &n->full, lru)
3694 p->slab = s;
3695#endif
3696 }
3697 }
3698}
3699
3700void __init kmem_cache_init(void)
3701{
3702 int i;
3703 int caches = 0;
3704 struct kmem_cache *temp_kmem_cache;
3705 int order;
3706 struct kmem_cache *temp_kmem_cache_node;
3707 unsigned long kmalloc_size;
3708
3709 if (debug_guardpage_minorder())
3710 slub_max_order = 0;
3711
3712 kmem_size = offsetof(struct kmem_cache, node) +
3713 nr_node_ids * sizeof(struct kmem_cache_node *);
3714
3715 /* Allocate two kmem_caches from the page allocator */
3716 kmalloc_size = ALIGN(kmem_size, cache_line_size());
3717 order = get_order(2 * kmalloc_size);
3718 kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
3719
3720 /*
3721 * Must first have the slab cache available for the allocations of the
3722 * struct kmem_cache_node's. There is special bootstrap code in
3723 * kmem_cache_open for slab_state == DOWN.
3724 */
3725 kmem_cache_node = (void *)kmem_cache + kmalloc_size;
3726
3727 kmem_cache_open(kmem_cache_node, "kmem_cache_node",
3728 sizeof(struct kmem_cache_node),
3729 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3730
3731 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3732
3733 /* Able to allocate the per node structures */
3734 slab_state = PARTIAL;
3735
3736 temp_kmem_cache = kmem_cache;
3737 kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
3738 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3739 kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3740 memcpy(kmem_cache, temp_kmem_cache, kmem_size);
3741
3742 /*
3743 * Allocate kmem_cache_node properly from the kmem_cache slab.
3744 * kmem_cache_node is separately allocated so no need to
3745 * update any list pointers.
3746 */
3747 temp_kmem_cache_node = kmem_cache_node;
3748
3749 kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3750 memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
3751
3752 kmem_cache_bootstrap_fixup(kmem_cache_node);
3753
3754 caches++;
3755 kmem_cache_bootstrap_fixup(kmem_cache);
3756 caches++;
3757 /* Free temporary boot structure */
3758 free_pages((unsigned long)temp_kmem_cache, order);
3759
3760 /* Now we can use the kmem_cache to allocate kmalloc slabs */
3761
3762 /*
3763 * Patch up the size_index table if we have strange large alignment
3764 * requirements for the kmalloc array. This is only the case for
3765 * MIPS it seems. The standard arches will not generate any code here.
3766 *
3767 * Largest permitted alignment is 256 bytes due to the way we
3768 * handle the index determination for the smaller caches.
3769 *
3770 * Make sure that nothing crazy happens if someone starts tinkering
3771 * around with ARCH_KMALLOC_MINALIGN
3772 */
3773 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3774 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3775
3776 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
3777 int elem = size_index_elem(i);
3778 if (elem >= ARRAY_SIZE(size_index))
3779 break;
3780 size_index[elem] = KMALLOC_SHIFT_LOW;
3781 }
3782
3783 if (KMALLOC_MIN_SIZE == 64) {
3784 /*
3785 * The 96 byte size cache is not used if the alignment
3786 * is 64 byte.
3787 */
3788 for (i = 64 + 8; i <= 96; i += 8)
3789 size_index[size_index_elem(i)] = 7;
3790 } else if (KMALLOC_MIN_SIZE == 128) {
3791 /*
3792 * The 192 byte sized cache is not used if the alignment
3793 * is 128 byte. Redirect kmalloc to use the 256 byte cache
3794 * instead.
3795 */
3796 for (i = 128 + 8; i <= 192; i += 8)
3797 size_index[size_index_elem(i)] = 8;
3798 }
3799
3800 /* Caches that are not of the two-to-the-power-of size */
3801 if (KMALLOC_MIN_SIZE <= 32) {
3802 kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
3803 caches++;
3804 }
3805
3806 if (KMALLOC_MIN_SIZE <= 64) {
3807 kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
3808 caches++;
3809 }
3810
3811 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3812 kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
3813 caches++;
3814 }
3815
3816 slab_state = UP;
3817
3818 /* Provide the correct kmalloc names now that the caches are up */
3819 if (KMALLOC_MIN_SIZE <= 32) {
3820 kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
3821 BUG_ON(!kmalloc_caches[1]->name);
3822 }
3823
3824 if (KMALLOC_MIN_SIZE <= 64) {
3825 kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
3826 BUG_ON(!kmalloc_caches[2]->name);
3827 }
3828
3829 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3830 char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
3831
3832 BUG_ON(!s);
3833 kmalloc_caches[i]->name = s;
3834 }
3835
3836#ifdef CONFIG_SMP
3837 register_cpu_notifier(&slab_notifier);
3838#endif
3839
3840#ifdef CONFIG_ZONE_DMA
3841 for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
3842 struct kmem_cache *s = kmalloc_caches[i];
3843
3844 if (s && s->size) {
3845 char *name = kasprintf(GFP_NOWAIT,
3846 "dma-kmalloc-%d", s->objsize);
3847
3848 BUG_ON(!name);
3849 kmalloc_dma_caches[i] = create_kmalloc_cache(name,
3850 s->objsize, SLAB_CACHE_DMA);
3851 }
3852 }
3853#endif
3854 printk(KERN_INFO
3855 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3856 " CPUs=%d, Nodes=%d\n",
3857 caches, cache_line_size(),
3858 slub_min_order, slub_max_order, slub_min_objects,
3859 nr_cpu_ids, nr_node_ids);
3860}
3861
3862void __init kmem_cache_init_late(void)
3863{
3864}
3865
3866/*
3867 * Find a mergeable slab cache
3868 */
3869static int slab_unmergeable(struct kmem_cache *s)
3870{
3871 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3872 return 1;
3873
3874 if (s->ctor)
3875 return 1;
3876
3877 /*
3878 * We may have set a slab to be unmergeable during bootstrap.
3879 */
3880 if (s->refcount < 0)
3881 return 1;
3882
3883 return 0;
3884}
3885
3886static struct kmem_cache *find_mergeable(size_t size,
3887 size_t align, unsigned long flags, const char *name,
3888 void (*ctor)(void *))
3889{
3890 struct kmem_cache *s;
3891
3892 if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3893 return NULL;
3894
3895 if (ctor)
3896 return NULL;
3897
3898 size = ALIGN(size, sizeof(void *));
3899 align = calculate_alignment(flags, align, size);
3900 size = ALIGN(size, align);
3901 flags = kmem_cache_flags(size, flags, name, NULL);
3902
3903 list_for_each_entry(s, &slab_caches, list) {
3904 if (slab_unmergeable(s))
3905 continue;
3906
3907 if (size > s->size)
3908 continue;
3909
3910 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3911 continue;
3912 /*
3913 * Check if alignment is compatible.
3914 * Courtesy of Adrian Drzewiecki
3915 */
3916 if ((s->size & ~(align - 1)) != s->size)
3917 continue;
3918
3919 if (s->size - size >= sizeof(void *))
3920 continue;
3921
3922 return s;
3923 }
3924 return NULL;
3925}
3926
3927struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3928 size_t align, unsigned long flags, void (*ctor)(void *))
3929{
3930 struct kmem_cache *s;
3931 char *n;
3932
3933 if (WARN_ON(!name))
3934 return NULL;
3935
3936 down_write(&slub_lock);
3937 s = find_mergeable(size, align, flags, name, ctor);
3938 if (s) {
3939 s->refcount++;
3940 /*
3941 * Adjust the object sizes so that we clear
3942 * the complete object on kzalloc.
3943 */
3944 s->objsize = max(s->objsize, (int)size);
3945 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3946
3947 if (sysfs_slab_alias(s, name)) {
3948 s->refcount--;
3949 goto err;
3950 }
3951 up_write(&slub_lock);
3952 return s;
3953 }
3954
3955 n = kstrdup(name, GFP_KERNEL);
3956 if (!n)
3957 goto err;
3958
3959 s = kmalloc(kmem_size, GFP_KERNEL);
3960 if (s) {
3961 if (kmem_cache_open(s, n,
3962 size, align, flags, ctor)) {
3963 list_add(&s->list, &slab_caches);
3964 up_write(&slub_lock);
3965 if (sysfs_slab_add(s)) {
3966 down_write(&slub_lock);
3967 list_del(&s->list);
3968 kfree(n);
3969 kfree(s);
3970 goto err;
3971 }
3972 return s;
3973 }
3974 kfree(s);
3975 }
3976 kfree(n);
3977err:
3978 up_write(&slub_lock);
3979
3980 if (flags & SLAB_PANIC)
3981 panic("Cannot create slabcache %s\n", name);
3982 else
3983 s = NULL;
3984 return s;
3985}
3986EXPORT_SYMBOL(kmem_cache_create);
3987
3988#ifdef CONFIG_SMP
3989/*
3990 * Use the cpu notifier to insure that the cpu slabs are flushed when
3991 * necessary.
3992 */
3993static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3994 unsigned long action, void *hcpu)
3995{
3996 long cpu = (long)hcpu;
3997 struct kmem_cache *s;
3998 unsigned long flags;
3999
4000 switch (action) {
4001 case CPU_UP_CANCELED:
4002 case CPU_UP_CANCELED_FROZEN:
4003 case CPU_DEAD:
4004 case CPU_DEAD_FROZEN:
4005 down_read(&slub_lock);
4006 list_for_each_entry(s, &slab_caches, list) {
4007 local_irq_save(flags);
4008 __flush_cpu_slab(s, cpu);
4009 local_irq_restore(flags);
4010 }
4011 up_read(&slub_lock);
4012 break;
4013 default:
4014 break;
4015 }
4016 return NOTIFY_OK;
4017}
4018
4019static struct notifier_block __cpuinitdata slab_notifier = {
4020 .notifier_call = slab_cpuup_callback
4021};
4022
4023#endif
4024
4025void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4026{
4027 struct kmem_cache *s;
4028 void *ret;
4029
4030 if (unlikely(size > SLUB_MAX_SIZE))
4031 return kmalloc_large(size, gfpflags);
4032
4033 s = get_slab(size, gfpflags);
4034
4035 if (unlikely(ZERO_OR_NULL_PTR(s)))
4036 return s;
4037
4038 ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, caller);
4039
4040 /* Honor the call site pointer we received. */
4041 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4042
4043 return ret;
4044}
4045
4046#ifdef CONFIG_NUMA
4047void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4048 int node, unsigned long caller)
4049{
4050 struct kmem_cache *s;
4051 void *ret;
4052
4053 if (unlikely(size > SLUB_MAX_SIZE)) {
4054 ret = kmalloc_large_node(size, gfpflags, node);
4055
4056 trace_kmalloc_node(caller, ret,
4057 size, PAGE_SIZE << get_order(size),
4058 gfpflags, node);
4059
4060 return ret;
4061 }
4062
4063 s = get_slab(size, gfpflags);
4064
4065 if (unlikely(ZERO_OR_NULL_PTR(s)))
4066 return s;
4067
4068 ret = slab_alloc(s, gfpflags, node, caller);
4069
4070 /* Honor the call site pointer we received. */
4071 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4072
4073 return ret;
4074}
4075#endif
4076
4077#ifdef CONFIG_SYSFS
4078static int count_inuse(struct page *page)
4079{
4080 return page->inuse;
4081}
4082
4083static int count_total(struct page *page)
4084{
4085 return page->objects;
4086}
4087#endif
4088
4089#ifdef CONFIG_SLUB_DEBUG
4090static int validate_slab(struct kmem_cache *s, struct page *page,
4091 unsigned long *map)
4092{
4093 void *p;
4094 void *addr = page_address(page);
4095
4096 if (!check_slab(s, page) ||
4097 !on_freelist(s, page, NULL))
4098 return 0;
4099
4100 /* Now we know that a valid freelist exists */
4101 bitmap_zero(map, page->objects);
4102
4103 get_map(s, page, map);
4104 for_each_object(p, s, addr, page->objects) {
4105 if (test_bit(slab_index(p, s, addr), map))
4106 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4107 return 0;
4108 }
4109
4110 for_each_object(p, s, addr, page->objects)
4111 if (!test_bit(slab_index(p, s, addr), map))
4112 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4113 return 0;
4114 return 1;
4115}
4116
4117static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4118 unsigned long *map)
4119{
4120 slab_lock(page);
4121 validate_slab(s, page, map);
4122 slab_unlock(page);
4123}
4124
4125static int validate_slab_node(struct kmem_cache *s,
4126 struct kmem_cache_node *n, unsigned long *map)
4127{
4128 unsigned long count = 0;
4129 struct page *page;
4130 unsigned long flags;
4131
4132 spin_lock_irqsave(&n->list_lock, flags);
4133
4134 list_for_each_entry(page, &n->partial, lru) {
4135 validate_slab_slab(s, page, map);
4136 count++;
4137 }
4138 if (count != n->nr_partial)
4139 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
4140 "counter=%ld\n", s->name, count, n->nr_partial);
4141
4142 if (!(s->flags & SLAB_STORE_USER))
4143 goto out;
4144
4145 list_for_each_entry(page, &n->full, lru) {
4146 validate_slab_slab(s, page, map);
4147 count++;
4148 }
4149 if (count != atomic_long_read(&n->nr_slabs))
4150 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
4151 "counter=%ld\n", s->name, count,
4152 atomic_long_read(&n->nr_slabs));
4153
4154out:
4155 spin_unlock_irqrestore(&n->list_lock, flags);
4156 return count;
4157}
4158
4159static long validate_slab_cache(struct kmem_cache *s)
4160{
4161 int node;
4162 unsigned long count = 0;
4163 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4164 sizeof(unsigned long), GFP_KERNEL);
4165
4166 if (!map)
4167 return -ENOMEM;
4168
4169 flush_all(s);
4170 for_each_node_state(node, N_NORMAL_MEMORY) {
4171 struct kmem_cache_node *n = get_node(s, node);
4172
4173 count += validate_slab_node(s, n, map);
4174 }
4175 kfree(map);
4176 return count;
4177}
4178/*
4179 * Generate lists of code addresses where slabcache objects are allocated
4180 * and freed.
4181 */
4182
4183struct location {
4184 unsigned long count;
4185 unsigned long addr;
4186 long long sum_time;
4187 long min_time;
4188 long max_time;
4189 long min_pid;
4190 long max_pid;
4191 DECLARE_BITMAP(cpus, NR_CPUS);
4192 nodemask_t nodes;
4193};
4194
4195struct loc_track {
4196 unsigned long max;
4197 unsigned long count;
4198 struct location *loc;
4199};
4200
4201static void free_loc_track(struct loc_track *t)
4202{
4203 if (t->max)
4204 free_pages((unsigned long)t->loc,
4205 get_order(sizeof(struct location) * t->max));
4206}
4207
4208static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4209{
4210 struct location *l;
4211 int order;
4212
4213 order = get_order(sizeof(struct location) * max);
4214
4215 l = (void *)__get_free_pages(flags, order);
4216 if (!l)
4217 return 0;
4218
4219 if (t->count) {
4220 memcpy(l, t->loc, sizeof(struct location) * t->count);
4221 free_loc_track(t);
4222 }
4223 t->max = max;
4224 t->loc = l;
4225 return 1;
4226}
4227
4228static int add_location(struct loc_track *t, struct kmem_cache *s,
4229 const struct track *track)
4230{
4231 long start, end, pos;
4232 struct location *l;
4233 unsigned long caddr;
4234 unsigned long age = jiffies - track->when;
4235
4236 start = -1;
4237 end = t->count;
4238
4239 for ( ; ; ) {
4240 pos = start + (end - start + 1) / 2;
4241
4242 /*
4243 * There is nothing at "end". If we end up there
4244 * we need to add something to before end.
4245 */
4246 if (pos == end)
4247 break;
4248
4249 caddr = t->loc[pos].addr;
4250 if (track->addr == caddr) {
4251
4252 l = &t->loc[pos];
4253 l->count++;
4254 if (track->when) {
4255 l->sum_time += age;
4256 if (age < l->min_time)
4257 l->min_time = age;
4258 if (age > l->max_time)
4259 l->max_time = age;
4260
4261 if (track->pid < l->min_pid)
4262 l->min_pid = track->pid;
4263 if (track->pid > l->max_pid)
4264 l->max_pid = track->pid;
4265
4266 cpumask_set_cpu(track->cpu,
4267 to_cpumask(l->cpus));
4268 }
4269 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4270 return 1;
4271 }
4272
4273 if (track->addr < caddr)
4274 end = pos;
4275 else
4276 start = pos;
4277 }
4278
4279 /*
4280 * Not found. Insert new tracking element.
4281 */
4282 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4283 return 0;
4284
4285 l = t->loc + pos;
4286 if (pos < t->count)
4287 memmove(l + 1, l,
4288 (t->count - pos) * sizeof(struct location));
4289 t->count++;
4290 l->count = 1;
4291 l->addr = track->addr;
4292 l->sum_time = age;
4293 l->min_time = age;
4294 l->max_time = age;
4295 l->min_pid = track->pid;
4296 l->max_pid = track->pid;
4297 cpumask_clear(to_cpumask(l->cpus));
4298 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4299 nodes_clear(l->nodes);
4300 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4301 return 1;
4302}
4303
4304static void process_slab(struct loc_track *t, struct kmem_cache *s,
4305 struct page *page, enum track_item alloc,
4306 unsigned long *map)
4307{
4308 void *addr = page_address(page);
4309 void *p;
4310
4311 bitmap_zero(map, page->objects);
4312 get_map(s, page, map);
4313
4314 for_each_object(p, s, addr, page->objects)
4315 if (!test_bit(slab_index(p, s, addr), map))
4316 add_location(t, s, get_track(s, p, alloc));
4317}
4318
4319static int list_locations(struct kmem_cache *s, char *buf,
4320 enum track_item alloc)
4321{
4322 int len = 0;
4323 unsigned long i;
4324 struct loc_track t = { 0, 0, NULL };
4325 int node;
4326 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4327 sizeof(unsigned long), GFP_KERNEL);
4328
4329 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4330 GFP_TEMPORARY)) {
4331 kfree(map);
4332 return sprintf(buf, "Out of memory\n");
4333 }
4334 /* Push back cpu slabs */
4335 flush_all(s);
4336
4337 for_each_node_state(node, N_NORMAL_MEMORY) {
4338 struct kmem_cache_node *n = get_node(s, node);
4339 unsigned long flags;
4340 struct page *page;
4341
4342 if (!atomic_long_read(&n->nr_slabs))
4343 continue;
4344
4345 spin_lock_irqsave(&n->list_lock, flags);
4346 list_for_each_entry(page, &n->partial, lru)
4347 process_slab(&t, s, page, alloc, map);
4348 list_for_each_entry(page, &n->full, lru)
4349 process_slab(&t, s, page, alloc, map);
4350 spin_unlock_irqrestore(&n->list_lock, flags);
4351 }
4352
4353 for (i = 0; i < t.count; i++) {
4354 struct location *l = &t.loc[i];
4355
4356 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4357 break;
4358 len += sprintf(buf + len, "%7ld ", l->count);
4359
4360 if (l->addr)
4361 len += sprintf(buf + len, "%pS", (void *)l->addr);
4362 else
4363 len += sprintf(buf + len, "<not-available>");
4364
4365 if (l->sum_time != l->min_time) {
4366 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4367 l->min_time,
4368 (long)div_u64(l->sum_time, l->count),
4369 l->max_time);
4370 } else
4371 len += sprintf(buf + len, " age=%ld",
4372 l->min_time);
4373
4374 if (l->min_pid != l->max_pid)
4375 len += sprintf(buf + len, " pid=%ld-%ld",
4376 l->min_pid, l->max_pid);
4377 else
4378 len += sprintf(buf + len, " pid=%ld",
4379 l->min_pid);
4380
4381 if (num_online_cpus() > 1 &&
4382 !cpumask_empty(to_cpumask(l->cpus)) &&
4383 len < PAGE_SIZE - 60) {
4384 len += sprintf(buf + len, " cpus=");
4385 len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4386 to_cpumask(l->cpus));
4387 }
4388
4389 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4390 len < PAGE_SIZE - 60) {
4391 len += sprintf(buf + len, " nodes=");
4392 len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4393 l->nodes);
4394 }
4395
4396 len += sprintf(buf + len, "\n");
4397 }
4398
4399 free_loc_track(&t);
4400 kfree(map);
4401 if (!t.count)
4402 len += sprintf(buf, "No data\n");
4403 return len;
4404}
4405#endif
4406
4407#ifdef SLUB_RESILIENCY_TEST
4408static void resiliency_test(void)
4409{
4410 u8 *p;
4411
4412 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
4413
4414 printk(KERN_ERR "SLUB resiliency testing\n");
4415 printk(KERN_ERR "-----------------------\n");
4416 printk(KERN_ERR "A. Corruption after allocation\n");
4417
4418 p = kzalloc(16, GFP_KERNEL);
4419 p[16] = 0x12;
4420 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4421 " 0x12->0x%p\n\n", p + 16);
4422
4423 validate_slab_cache(kmalloc_caches[4]);
4424
4425 /* Hmmm... The next two are dangerous */
4426 p = kzalloc(32, GFP_KERNEL);
4427 p[32 + sizeof(void *)] = 0x34;
4428 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4429 " 0x34 -> -0x%p\n", p);
4430 printk(KERN_ERR
4431 "If allocated object is overwritten then not detectable\n\n");
4432
4433 validate_slab_cache(kmalloc_caches[5]);
4434 p = kzalloc(64, GFP_KERNEL);
4435 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4436 *p = 0x56;
4437 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4438 p);
4439 printk(KERN_ERR
4440 "If allocated object is overwritten then not detectable\n\n");
4441 validate_slab_cache(kmalloc_caches[6]);
4442
4443 printk(KERN_ERR "\nB. Corruption after free\n");
4444 p = kzalloc(128, GFP_KERNEL);
4445 kfree(p);
4446 *p = 0x78;
4447 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4448 validate_slab_cache(kmalloc_caches[7]);
4449
4450 p = kzalloc(256, GFP_KERNEL);
4451 kfree(p);
4452 p[50] = 0x9a;
4453 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4454 p);
4455 validate_slab_cache(kmalloc_caches[8]);
4456
4457 p = kzalloc(512, GFP_KERNEL);
4458 kfree(p);
4459 p[512] = 0xab;
4460 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4461 validate_slab_cache(kmalloc_caches[9]);
4462}
4463#else
4464#ifdef CONFIG_SYSFS
4465static void resiliency_test(void) {};
4466#endif
4467#endif
4468
4469#ifdef CONFIG_SYSFS
4470enum slab_stat_type {
4471 SL_ALL, /* All slabs */
4472 SL_PARTIAL, /* Only partially allocated slabs */
4473 SL_CPU, /* Only slabs used for cpu caches */
4474 SL_OBJECTS, /* Determine allocated objects not slabs */
4475 SL_TOTAL /* Determine object capacity not slabs */
4476};
4477
4478#define SO_ALL (1 << SL_ALL)
4479#define SO_PARTIAL (1 << SL_PARTIAL)
4480#define SO_CPU (1 << SL_CPU)
4481#define SO_OBJECTS (1 << SL_OBJECTS)
4482#define SO_TOTAL (1 << SL_TOTAL)
4483
4484static ssize_t show_slab_objects(struct kmem_cache *s,
4485 char *buf, unsigned long flags)
4486{
4487 unsigned long total = 0;
4488 int node;
4489 int x;
4490 unsigned long *nodes;
4491 unsigned long *per_cpu;
4492
4493 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4494 if (!nodes)
4495 return -ENOMEM;
4496 per_cpu = nodes + nr_node_ids;
4497
4498 if (flags & SO_CPU) {
4499 int cpu;
4500
4501 for_each_possible_cpu(cpu) {
4502 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
4503 int node = ACCESS_ONCE(c->node);
4504 struct page *page;
4505
4506 if (node < 0)
4507 continue;
4508 page = ACCESS_ONCE(c->page);
4509 if (page) {
4510 if (flags & SO_TOTAL)
4511 x = page->objects;
4512 else if (flags & SO_OBJECTS)
4513 x = page->inuse;
4514 else
4515 x = 1;
4516
4517 total += x;
4518 nodes[node] += x;
4519 }
4520 page = c->partial;
4521
4522 if (page) {
4523 x = page->pobjects;
4524 total += x;
4525 nodes[node] += x;
4526 }
4527 per_cpu[node]++;
4528 }
4529 }
4530
4531 lock_memory_hotplug();
4532#ifdef CONFIG_SLUB_DEBUG
4533 if (flags & SO_ALL) {
4534 for_each_node_state(node, N_NORMAL_MEMORY) {
4535 struct kmem_cache_node *n = get_node(s, node);
4536
4537 if (flags & SO_TOTAL)
4538 x = atomic_long_read(&n->total_objects);
4539 else if (flags & SO_OBJECTS)
4540 x = atomic_long_read(&n->total_objects) -
4541 count_partial(n, count_free);
4542
4543 else
4544 x = atomic_long_read(&n->nr_slabs);
4545 total += x;
4546 nodes[node] += x;
4547 }
4548
4549 } else
4550#endif
4551 if (flags & SO_PARTIAL) {
4552 for_each_node_state(node, N_NORMAL_MEMORY) {
4553 struct kmem_cache_node *n = get_node(s, node);
4554
4555 if (flags & SO_TOTAL)
4556 x = count_partial(n, count_total);
4557 else if (flags & SO_OBJECTS)
4558 x = count_partial(n, count_inuse);
4559 else
4560 x = n->nr_partial;
4561 total += x;
4562 nodes[node] += x;
4563 }
4564 }
4565 x = sprintf(buf, "%lu", total);
4566#ifdef CONFIG_NUMA
4567 for_each_node_state(node, N_NORMAL_MEMORY)
4568 if (nodes[node])
4569 x += sprintf(buf + x, " N%d=%lu",
4570 node, nodes[node]);
4571#endif
4572 unlock_memory_hotplug();
4573 kfree(nodes);
4574 return x + sprintf(buf + x, "\n");
4575}
4576
4577#ifdef CONFIG_SLUB_DEBUG
4578static int any_slab_objects(struct kmem_cache *s)
4579{
4580 int node;
4581
4582 for_each_online_node(node) {
4583 struct kmem_cache_node *n = get_node(s, node);
4584
4585 if (!n)
4586 continue;
4587
4588 if (atomic_long_read(&n->total_objects))
4589 return 1;
4590 }
4591 return 0;
4592}
4593#endif
4594
4595#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4596#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4597
4598struct slab_attribute {
4599 struct attribute attr;
4600 ssize_t (*show)(struct kmem_cache *s, char *buf);
4601 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4602};
4603
4604#define SLAB_ATTR_RO(_name) \
4605 static struct slab_attribute _name##_attr = \
4606 __ATTR(_name, 0400, _name##_show, NULL)
4607
4608#define SLAB_ATTR(_name) \
4609 static struct slab_attribute _name##_attr = \
4610 __ATTR(_name, 0600, _name##_show, _name##_store)
4611
4612static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4613{
4614 return sprintf(buf, "%d\n", s->size);
4615}
4616SLAB_ATTR_RO(slab_size);
4617
4618static ssize_t align_show(struct kmem_cache *s, char *buf)
4619{
4620 return sprintf(buf, "%d\n", s->align);
4621}
4622SLAB_ATTR_RO(align);
4623
4624static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4625{
4626 return sprintf(buf, "%d\n", s->objsize);
4627}
4628SLAB_ATTR_RO(object_size);
4629
4630static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4631{
4632 return sprintf(buf, "%d\n", oo_objects(s->oo));
4633}
4634SLAB_ATTR_RO(objs_per_slab);
4635
4636static ssize_t order_store(struct kmem_cache *s,
4637 const char *buf, size_t length)
4638{
4639 unsigned long order;
4640 int err;
4641
4642 err = strict_strtoul(buf, 10, &order);
4643 if (err)
4644 return err;
4645
4646 if (order > slub_max_order || order < slub_min_order)
4647 return -EINVAL;
4648
4649 calculate_sizes(s, order);
4650 return length;
4651}
4652
4653static ssize_t order_show(struct kmem_cache *s, char *buf)
4654{
4655 return sprintf(buf, "%d\n", oo_order(s->oo));
4656}
4657SLAB_ATTR(order);
4658
4659static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4660{
4661 return sprintf(buf, "%lu\n", s->min_partial);
4662}
4663
4664static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4665 size_t length)
4666{
4667 unsigned long min;
4668 int err;
4669
4670 err = strict_strtoul(buf, 10, &min);
4671 if (err)
4672 return err;
4673
4674 set_min_partial(s, min);
4675 return length;
4676}
4677SLAB_ATTR(min_partial);
4678
4679static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4680{
4681 return sprintf(buf, "%u\n", s->cpu_partial);
4682}
4683
4684static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4685 size_t length)
4686{
4687 unsigned long objects;
4688 int err;
4689
4690 err = strict_strtoul(buf, 10, &objects);
4691 if (err)
4692 return err;
4693 if (objects && kmem_cache_debug(s))
4694 return -EINVAL;
4695
4696 s->cpu_partial = objects;
4697 flush_all(s);
4698 return length;
4699}
4700SLAB_ATTR(cpu_partial);
4701
4702static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4703{
4704 if (!s->ctor)
4705 return 0;
4706 return sprintf(buf, "%pS\n", s->ctor);
4707}
4708SLAB_ATTR_RO(ctor);
4709
4710static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4711{
4712 return sprintf(buf, "%d\n", s->refcount - 1);
4713}
4714SLAB_ATTR_RO(aliases);
4715
4716static ssize_t partial_show(struct kmem_cache *s, char *buf)
4717{
4718 return show_slab_objects(s, buf, SO_PARTIAL);
4719}
4720SLAB_ATTR_RO(partial);
4721
4722static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4723{
4724 return show_slab_objects(s, buf, SO_CPU);
4725}
4726SLAB_ATTR_RO(cpu_slabs);
4727
4728static ssize_t objects_show(struct kmem_cache *s, char *buf)
4729{
4730 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4731}
4732SLAB_ATTR_RO(objects);
4733
4734static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4735{
4736 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4737}
4738SLAB_ATTR_RO(objects_partial);
4739
4740static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4741{
4742 int objects = 0;
4743 int pages = 0;
4744 int cpu;
4745 int len;
4746
4747 for_each_online_cpu(cpu) {
4748 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4749
4750 if (page) {
4751 pages += page->pages;
4752 objects += page->pobjects;
4753 }
4754 }
4755
4756 len = sprintf(buf, "%d(%d)", objects, pages);
4757
4758#ifdef CONFIG_SMP
4759 for_each_online_cpu(cpu) {
4760 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4761
4762 if (page && len < PAGE_SIZE - 20)
4763 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4764 page->pobjects, page->pages);
4765 }
4766#endif
4767 return len + sprintf(buf + len, "\n");
4768}
4769SLAB_ATTR_RO(slabs_cpu_partial);
4770
4771static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4772{
4773 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4774}
4775
4776static ssize_t reclaim_account_store(struct kmem_cache *s,
4777 const char *buf, size_t length)
4778{
4779 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4780 if (buf[0] == '1')
4781 s->flags |= SLAB_RECLAIM_ACCOUNT;
4782 return length;
4783}
4784SLAB_ATTR(reclaim_account);
4785
4786static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4787{
4788 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4789}
4790SLAB_ATTR_RO(hwcache_align);
4791
4792#ifdef CONFIG_ZONE_DMA
4793static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4794{
4795 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4796}
4797SLAB_ATTR_RO(cache_dma);
4798#endif
4799
4800static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4801{
4802 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4803}
4804SLAB_ATTR_RO(destroy_by_rcu);
4805
4806static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4807{
4808 return sprintf(buf, "%d\n", s->reserved);
4809}
4810SLAB_ATTR_RO(reserved);
4811
4812#ifdef CONFIG_SLUB_DEBUG
4813static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4814{
4815 return show_slab_objects(s, buf, SO_ALL);
4816}
4817SLAB_ATTR_RO(slabs);
4818
4819static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4820{
4821 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4822}
4823SLAB_ATTR_RO(total_objects);
4824
4825static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4826{
4827 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4828}
4829
4830static ssize_t sanity_checks_store(struct kmem_cache *s,
4831 const char *buf, size_t length)
4832{
4833 s->flags &= ~SLAB_DEBUG_FREE;
4834 if (buf[0] == '1') {
4835 s->flags &= ~__CMPXCHG_DOUBLE;
4836 s->flags |= SLAB_DEBUG_FREE;
4837 }
4838 return length;
4839}
4840SLAB_ATTR(sanity_checks);
4841
4842static ssize_t trace_show(struct kmem_cache *s, char *buf)
4843{
4844 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4845}
4846
4847static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4848 size_t length)
4849{
4850 s->flags &= ~SLAB_TRACE;
4851 if (buf[0] == '1') {
4852 s->flags &= ~__CMPXCHG_DOUBLE;
4853 s->flags |= SLAB_TRACE;
4854 }
4855 return length;
4856}
4857SLAB_ATTR(trace);
4858
4859static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4860{
4861 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4862}
4863
4864static ssize_t red_zone_store(struct kmem_cache *s,
4865 const char *buf, size_t length)
4866{
4867 if (any_slab_objects(s))
4868 return -EBUSY;
4869
4870 s->flags &= ~SLAB_RED_ZONE;
4871 if (buf[0] == '1') {
4872 s->flags &= ~__CMPXCHG_DOUBLE;
4873 s->flags |= SLAB_RED_ZONE;
4874 }
4875 calculate_sizes(s, -1);
4876 return length;
4877}
4878SLAB_ATTR(red_zone);
4879
4880static ssize_t poison_show(struct kmem_cache *s, char *buf)
4881{
4882 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4883}
4884
4885static ssize_t poison_store(struct kmem_cache *s,
4886 const char *buf, size_t length)
4887{
4888 if (any_slab_objects(s))
4889 return -EBUSY;
4890
4891 s->flags &= ~SLAB_POISON;
4892 if (buf[0] == '1') {
4893 s->flags &= ~__CMPXCHG_DOUBLE;
4894 s->flags |= SLAB_POISON;
4895 }
4896 calculate_sizes(s, -1);
4897 return length;
4898}
4899SLAB_ATTR(poison);
4900
4901static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4902{
4903 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4904}
4905
4906static ssize_t store_user_store(struct kmem_cache *s,
4907 const char *buf, size_t length)
4908{
4909 if (any_slab_objects(s))
4910 return -EBUSY;
4911
4912 s->flags &= ~SLAB_STORE_USER;
4913 if (buf[0] == '1') {
4914 s->flags &= ~__CMPXCHG_DOUBLE;
4915 s->flags |= SLAB_STORE_USER;
4916 }
4917 calculate_sizes(s, -1);
4918 return length;
4919}
4920SLAB_ATTR(store_user);
4921
4922static ssize_t validate_show(struct kmem_cache *s, char *buf)
4923{
4924 return 0;
4925}
4926
4927static ssize_t validate_store(struct kmem_cache *s,
4928 const char *buf, size_t length)
4929{
4930 int ret = -EINVAL;
4931
4932 if (buf[0] == '1') {
4933 ret = validate_slab_cache(s);
4934 if (ret >= 0)
4935 ret = length;
4936 }
4937 return ret;
4938}
4939SLAB_ATTR(validate);
4940
4941static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4942{
4943 if (!(s->flags & SLAB_STORE_USER))
4944 return -ENOSYS;
4945 return list_locations(s, buf, TRACK_ALLOC);
4946}
4947SLAB_ATTR_RO(alloc_calls);
4948
4949static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4950{
4951 if (!(s->flags & SLAB_STORE_USER))
4952 return -ENOSYS;
4953 return list_locations(s, buf, TRACK_FREE);
4954}
4955SLAB_ATTR_RO(free_calls);
4956#endif /* CONFIG_SLUB_DEBUG */
4957
4958#ifdef CONFIG_FAILSLAB
4959static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4960{
4961 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4962}
4963
4964static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4965 size_t length)
4966{
4967 s->flags &= ~SLAB_FAILSLAB;
4968 if (buf[0] == '1')
4969 s->flags |= SLAB_FAILSLAB;
4970 return length;
4971}
4972SLAB_ATTR(failslab);
4973#endif
4974
4975static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4976{
4977 return 0;
4978}
4979
4980static ssize_t shrink_store(struct kmem_cache *s,
4981 const char *buf, size_t length)
4982{
4983 if (buf[0] == '1') {
4984 int rc = kmem_cache_shrink(s);
4985
4986 if (rc)
4987 return rc;
4988 } else
4989 return -EINVAL;
4990 return length;
4991}
4992SLAB_ATTR(shrink);
4993
4994#ifdef CONFIG_NUMA
4995static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4996{
4997 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4998}
4999
5000static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5001 const char *buf, size_t length)
5002{
5003 unsigned long ratio;
5004 int err;
5005
5006 err = strict_strtoul(buf, 10, &ratio);
5007 if (err)
5008 return err;
5009
5010 if (ratio <= 100)
5011 s->remote_node_defrag_ratio = ratio * 10;
5012
5013 return length;
5014}
5015SLAB_ATTR(remote_node_defrag_ratio);
5016#endif
5017
5018#ifdef CONFIG_SLUB_STATS
5019static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5020{
5021 unsigned long sum = 0;
5022 int cpu;
5023 int len;
5024 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5025
5026 if (!data)
5027 return -ENOMEM;
5028
5029 for_each_online_cpu(cpu) {
5030 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5031
5032 data[cpu] = x;
5033 sum += x;
5034 }
5035
5036 len = sprintf(buf, "%lu", sum);
5037
5038#ifdef CONFIG_SMP
5039 for_each_online_cpu(cpu) {
5040 if (data[cpu] && len < PAGE_SIZE - 20)
5041 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5042 }
5043#endif
5044 kfree(data);
5045 return len + sprintf(buf + len, "\n");
5046}
5047
5048static void clear_stat(struct kmem_cache *s, enum stat_item si)
5049{
5050 int cpu;
5051
5052 for_each_online_cpu(cpu)
5053 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5054}
5055
5056#define STAT_ATTR(si, text) \
5057static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5058{ \
5059 return show_stat(s, buf, si); \
5060} \
5061static ssize_t text##_store(struct kmem_cache *s, \
5062 const char *buf, size_t length) \
5063{ \
5064 if (buf[0] != '0') \
5065 return -EINVAL; \
5066 clear_stat(s, si); \
5067 return length; \
5068} \
5069SLAB_ATTR(text); \
5070
5071STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5072STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5073STAT_ATTR(FREE_FASTPATH, free_fastpath);
5074STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5075STAT_ATTR(FREE_FROZEN, free_frozen);
5076STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5077STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5078STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5079STAT_ATTR(ALLOC_SLAB, alloc_slab);
5080STAT_ATTR(ALLOC_REFILL, alloc_refill);
5081STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5082STAT_ATTR(FREE_SLAB, free_slab);
5083STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5084STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5085STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5086STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5087STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5088STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5089STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5090STAT_ATTR(ORDER_FALLBACK, order_fallback);
5091STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5092STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5093STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5094STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5095STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5096STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5097#endif
5098
5099static struct attribute *slab_attrs[] = {
5100 &slab_size_attr.attr,
5101 &object_size_attr.attr,
5102 &objs_per_slab_attr.attr,
5103 &order_attr.attr,
5104 &min_partial_attr.attr,
5105 &cpu_partial_attr.attr,
5106 &objects_attr.attr,
5107 &objects_partial_attr.attr,
5108 &partial_attr.attr,
5109 &cpu_slabs_attr.attr,
5110 &ctor_attr.attr,
5111 &aliases_attr.attr,
5112 &align_attr.attr,
5113 &hwcache_align_attr.attr,
5114 &reclaim_account_attr.attr,
5115 &destroy_by_rcu_attr.attr,
5116 &shrink_attr.attr,
5117 &reserved_attr.attr,
5118 &slabs_cpu_partial_attr.attr,
5119#ifdef CONFIG_SLUB_DEBUG
5120 &total_objects_attr.attr,
5121 &slabs_attr.attr,
5122 &sanity_checks_attr.attr,
5123 &trace_attr.attr,
5124 &red_zone_attr.attr,
5125 &poison_attr.attr,
5126 &store_user_attr.attr,
5127 &validate_attr.attr,
5128 &alloc_calls_attr.attr,
5129 &free_calls_attr.attr,
5130#endif
5131#ifdef CONFIG_ZONE_DMA
5132 &cache_dma_attr.attr,
5133#endif
5134#ifdef CONFIG_NUMA
5135 &remote_node_defrag_ratio_attr.attr,
5136#endif
5137#ifdef CONFIG_SLUB_STATS
5138 &alloc_fastpath_attr.attr,
5139 &alloc_slowpath_attr.attr,
5140 &free_fastpath_attr.attr,
5141 &free_slowpath_attr.attr,
5142 &free_frozen_attr.attr,
5143 &free_add_partial_attr.attr,
5144 &free_remove_partial_attr.attr,
5145 &alloc_from_partial_attr.attr,
5146 &alloc_slab_attr.attr,
5147 &alloc_refill_attr.attr,
5148 &alloc_node_mismatch_attr.attr,
5149 &free_slab_attr.attr,
5150 &cpuslab_flush_attr.attr,
5151 &deactivate_full_attr.attr,
5152 &deactivate_empty_attr.attr,
5153 &deactivate_to_head_attr.attr,
5154 &deactivate_to_tail_attr.attr,
5155 &deactivate_remote_frees_attr.attr,
5156 &deactivate_bypass_attr.attr,
5157 &order_fallback_attr.attr,
5158 &cmpxchg_double_fail_attr.attr,
5159 &cmpxchg_double_cpu_fail_attr.attr,
5160 &cpu_partial_alloc_attr.attr,
5161 &cpu_partial_free_attr.attr,
5162 &cpu_partial_node_attr.attr,
5163 &cpu_partial_drain_attr.attr,
5164#endif
5165#ifdef CONFIG_FAILSLAB
5166 &failslab_attr.attr,
5167#endif
5168
5169 NULL
5170};
5171
5172static struct attribute_group slab_attr_group = {
5173 .attrs = slab_attrs,
5174};
5175
5176static ssize_t slab_attr_show(struct kobject *kobj,
5177 struct attribute *attr,
5178 char *buf)
5179{
5180 struct slab_attribute *attribute;
5181 struct kmem_cache *s;
5182 int err;
5183
5184 attribute = to_slab_attr(attr);
5185 s = to_slab(kobj);
5186
5187 if (!attribute->show)
5188 return -EIO;
5189
5190 err = attribute->show(s, buf);
5191
5192 return err;
5193}
5194
5195static ssize_t slab_attr_store(struct kobject *kobj,
5196 struct attribute *attr,
5197 const char *buf, size_t len)
5198{
5199 struct slab_attribute *attribute;
5200 struct kmem_cache *s;
5201 int err;
5202
5203 attribute = to_slab_attr(attr);
5204 s = to_slab(kobj);
5205
5206 if (!attribute->store)
5207 return -EIO;
5208
5209 err = attribute->store(s, buf, len);
5210
5211 return err;
5212}
5213
5214static void kmem_cache_release(struct kobject *kobj)
5215{
5216 struct kmem_cache *s = to_slab(kobj);
5217
5218 kfree(s->name);
5219 kfree(s);
5220}
5221
5222static const struct sysfs_ops slab_sysfs_ops = {
5223 .show = slab_attr_show,
5224 .store = slab_attr_store,
5225};
5226
5227static struct kobj_type slab_ktype = {
5228 .sysfs_ops = &slab_sysfs_ops,
5229 .release = kmem_cache_release
5230};
5231
5232static int uevent_filter(struct kset *kset, struct kobject *kobj)
5233{
5234 struct kobj_type *ktype = get_ktype(kobj);
5235
5236 if (ktype == &slab_ktype)
5237 return 1;
5238 return 0;
5239}
5240
5241static const struct kset_uevent_ops slab_uevent_ops = {
5242 .filter = uevent_filter,
5243};
5244
5245static struct kset *slab_kset;
5246
5247#define ID_STR_LENGTH 64
5248
5249/* Create a unique string id for a slab cache:
5250 *
5251 * Format :[flags-]size
5252 */
5253static char *create_unique_id(struct kmem_cache *s)
5254{
5255 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5256 char *p = name;
5257
5258 BUG_ON(!name);
5259
5260 *p++ = ':';
5261 /*
5262 * First flags affecting slabcache operations. We will only
5263 * get here for aliasable slabs so we do not need to support
5264 * too many flags. The flags here must cover all flags that
5265 * are matched during merging to guarantee that the id is
5266 * unique.
5267 */
5268 if (s->flags & SLAB_CACHE_DMA)
5269 *p++ = 'd';
5270 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5271 *p++ = 'a';
5272 if (s->flags & SLAB_DEBUG_FREE)
5273 *p++ = 'F';
5274 if (!(s->flags & SLAB_NOTRACK))
5275 *p++ = 't';
5276 if (p != name + 1)
5277 *p++ = '-';
5278 p += sprintf(p, "%07d", s->size);
5279 BUG_ON(p > name + ID_STR_LENGTH - 1);
5280 return name;
5281}
5282
5283static int sysfs_slab_add(struct kmem_cache *s)
5284{
5285 int err;
5286 const char *name;
5287 int unmergeable;
5288
5289 if (slab_state < SYSFS)
5290 /* Defer until later */
5291 return 0;
5292
5293 unmergeable = slab_unmergeable(s);
5294 if (unmergeable) {
5295 /*
5296 * Slabcache can never be merged so we can use the name proper.
5297 * This is typically the case for debug situations. In that
5298 * case we can catch duplicate names easily.
5299 */
5300 sysfs_remove_link(&slab_kset->kobj, s->name);
5301 name = s->name;
5302 } else {
5303 /*
5304 * Create a unique name for the slab as a target
5305 * for the symlinks.
5306 */
5307 name = create_unique_id(s);
5308 }
5309
5310 s->kobj.kset = slab_kset;
5311 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5312 if (err) {
5313 kobject_put(&s->kobj);
5314 return err;
5315 }
5316
5317 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5318 if (err) {
5319 kobject_del(&s->kobj);
5320 kobject_put(&s->kobj);
5321 return err;
5322 }
5323 kobject_uevent(&s->kobj, KOBJ_ADD);
5324 if (!unmergeable) {
5325 /* Setup first alias */
5326 sysfs_slab_alias(s, s->name);
5327 kfree(name);
5328 }
5329 return 0;
5330}
5331
5332static void sysfs_slab_remove(struct kmem_cache *s)
5333{
5334 if (slab_state < SYSFS)
5335 /*
5336 * Sysfs has not been setup yet so no need to remove the
5337 * cache from sysfs.
5338 */
5339 return;
5340
5341 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5342 kobject_del(&s->kobj);
5343 kobject_put(&s->kobj);
5344}
5345
5346/*
5347 * Need to buffer aliases during bootup until sysfs becomes
5348 * available lest we lose that information.
5349 */
5350struct saved_alias {
5351 struct kmem_cache *s;
5352 const char *name;
5353 struct saved_alias *next;
5354};
5355
5356static struct saved_alias *alias_list;
5357
5358static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5359{
5360 struct saved_alias *al;
5361
5362 if (slab_state == SYSFS) {
5363 /*
5364 * If we have a leftover link then remove it.
5365 */
5366 sysfs_remove_link(&slab_kset->kobj, name);
5367 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5368 }
5369
5370 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5371 if (!al)
5372 return -ENOMEM;
5373
5374 al->s = s;
5375 al->name = name;
5376 al->next = alias_list;
5377 alias_list = al;
5378 return 0;
5379}
5380
5381static int __init slab_sysfs_init(void)
5382{
5383 struct kmem_cache *s;
5384 int err;
5385
5386 down_write(&slub_lock);
5387
5388 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5389 if (!slab_kset) {
5390 up_write(&slub_lock);
5391 printk(KERN_ERR "Cannot register slab subsystem.\n");
5392 return -ENOSYS;
5393 }
5394
5395 slab_state = SYSFS;
5396
5397 list_for_each_entry(s, &slab_caches, list) {
5398 err = sysfs_slab_add(s);
5399 if (err)
5400 printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5401 " to sysfs\n", s->name);
5402 }
5403
5404 while (alias_list) {
5405 struct saved_alias *al = alias_list;
5406
5407 alias_list = alias_list->next;
5408 err = sysfs_slab_alias(al->s, al->name);
5409 if (err)
5410 printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5411 " %s to sysfs\n", s->name);
5412 kfree(al);
5413 }
5414
5415 up_write(&slub_lock);
5416 resiliency_test();
5417 return 0;
5418}
5419
5420__initcall(slab_sysfs_init);
5421#endif /* CONFIG_SYSFS */
5422
5423/*
5424 * The /proc/slabinfo ABI
5425 */
5426#ifdef CONFIG_SLABINFO
5427static void print_slabinfo_header(struct seq_file *m)
5428{
5429 seq_puts(m, "slabinfo - version: 2.1\n");
5430 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
5431 "<objperslab> <pagesperslab>");
5432 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
5433 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
5434 seq_putc(m, '\n');
5435}
5436
5437static void *s_start(struct seq_file *m, loff_t *pos)
5438{
5439 loff_t n = *pos;
5440
5441 down_read(&slub_lock);
5442 if (!n)
5443 print_slabinfo_header(m);
5444
5445 return seq_list_start(&slab_caches, *pos);
5446}
5447
5448static void *s_next(struct seq_file *m, void *p, loff_t *pos)
5449{
5450 return seq_list_next(p, &slab_caches, pos);
5451}
5452
5453static void s_stop(struct seq_file *m, void *p)
5454{
5455 up_read(&slub_lock);
5456}
5457
5458static int s_show(struct seq_file *m, void *p)
5459{
5460 unsigned long nr_partials = 0;
5461 unsigned long nr_slabs = 0;
5462 unsigned long nr_inuse = 0;
5463 unsigned long nr_objs = 0;
5464 unsigned long nr_free = 0;
5465 struct kmem_cache *s;
5466 int node;
5467
5468 s = list_entry(p, struct kmem_cache, list);
5469
5470 for_each_online_node(node) {
5471 struct kmem_cache_node *n = get_node(s, node);
5472
5473 if (!n)
5474 continue;
5475
5476 nr_partials += n->nr_partial;
5477 nr_slabs += atomic_long_read(&n->nr_slabs);
5478 nr_objs += atomic_long_read(&n->total_objects);
5479 nr_free += count_partial(n, count_free);
5480 }
5481
5482 nr_inuse = nr_objs - nr_free;
5483
5484 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
5485 nr_objs, s->size, oo_objects(s->oo),
5486 (1 << oo_order(s->oo)));
5487 seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
5488 seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
5489 0UL);
5490 seq_putc(m, '\n');
5491 return 0;
5492}
5493
5494static const struct seq_operations slabinfo_op = {
5495 .start = s_start,
5496 .next = s_next,
5497 .stop = s_stop,
5498 .show = s_show,
5499};
5500
5501static int slabinfo_open(struct inode *inode, struct file *file)
5502{
5503 return seq_open(file, &slabinfo_op);
5504}
5505
5506static const struct file_operations proc_slabinfo_operations = {
5507 .open = slabinfo_open,
5508 .read = seq_read,
5509 .llseek = seq_lseek,
5510 .release = seq_release,
5511};
5512
5513static int __init slab_proc_init(void)
5514{
5515 proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
5516 return 0;
5517}
5518module_init(slab_proc_init);
5519#endif /* CONFIG_SLABINFO */