USB: fix bug in sg initialization in usbtest
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / slub.c
blobacc975fcc8cc9f96a9d3ce7d37a1e1e9b7bbf2ca
1 /*
2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
5 * The allocator synchronizes using per slab locks and only
6 * uses a centralized lock to manage a pool of partial slabs.
8 * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
9 */
11 #include <linux/mm.h>
12 #include <linux/module.h>
13 #include <linux/bit_spinlock.h>
14 #include <linux/interrupt.h>
15 #include <linux/bitops.h>
16 #include <linux/slab.h>
17 #include <linux/seq_file.h>
18 #include <linux/cpu.h>
19 #include <linux/cpuset.h>
20 #include <linux/mempolicy.h>
21 #include <linux/ctype.h>
22 #include <linux/kallsyms.h>
23 #include <linux/memory.h>
26 * Lock order:
27 * 1. slab_lock(page)
28 * 2. slab->list_lock
30 * The slab_lock protects operations on the object of a particular
31 * slab and its metadata in the page struct. If the slab lock
32 * has been taken then no allocations nor frees can be performed
33 * on the objects in the slab nor can the slab be added or removed
34 * from the partial or full lists since this would mean modifying
35 * the page_struct of the slab.
37 * The list_lock protects the partial and full list on each node and
38 * the partial slab counter. If taken then no new slabs may be added or
39 * removed from the lists nor make the number of partial slabs be modified.
40 * (Note that the total number of slabs is an atomic value that may be
41 * modified without taking the list lock).
43 * The list_lock is a centralized lock and thus we avoid taking it as
44 * much as possible. As long as SLUB does not have to handle partial
45 * slabs, operations can continue without any centralized lock. F.e.
46 * allocating a long series of objects that fill up slabs does not require
47 * the list lock.
49 * The lock order is sometimes inverted when we are trying to get a slab
50 * off a list. We take the list_lock and then look for a page on the list
51 * to use. While we do that objects in the slabs may be freed. We can
52 * only operate on the slab if we have also taken the slab_lock. So we use
53 * a slab_trylock() on the slab. If trylock was successful then no frees
54 * can occur anymore and we can use the slab for allocations etc. If the
55 * slab_trylock() does not succeed then frees are in progress in the slab and
56 * we must stay away from it for a while since we may cause a bouncing
57 * cacheline if we try to acquire the lock. So go onto the next slab.
58 * If all pages are busy then we may allocate a new slab instead of reusing
59 * a partial slab. A new slab has noone operating on it and thus there is
60 * no danger of cacheline contention.
62 * Interrupts are disabled during allocation and deallocation in order to
63 * make the slab allocator safe to use in the context of an irq. In addition
64 * interrupts are disabled to ensure that the processor does not change
65 * while handling per_cpu slabs, due to kernel preemption.
67 * SLUB assigns one slab for allocation to each processor.
68 * Allocations only occur from these slabs called cpu slabs.
70 * Slabs with free elements are kept on a partial list and during regular
71 * operations no list for full slabs is used. If an object in a full slab is
72 * freed then the slab will show up again on the partial lists.
73 * We track full slabs for debugging purposes though because otherwise we
74 * cannot scan all objects.
76 * Slabs are freed when they become empty. Teardown and setup is
77 * minimal so we rely on the page allocators per cpu caches for
78 * fast frees and allocs.
80 * Overloading of page flags that are otherwise used for LRU management.
82 * PageActive The slab is frozen and exempt from list processing.
83 * This means that the slab is dedicated to a purpose
84 * such as satisfying allocations for a specific
85 * processor. Objects may be freed in the slab while
86 * it is frozen but slab_free will then skip the usual
87 * list operations. It is up to the processor holding
88 * the slab to integrate the slab into the slab lists
89 * when the slab is no longer needed.
91 * One use of this flag is to mark slabs that are
92 * used for allocations. Then such a slab becomes a cpu
93 * slab. The cpu slab may be equipped with an additional
94 * freelist that allows lockless access to
95 * free objects in addition to the regular freelist
96 * that requires the slab lock.
98 * PageError Slab requires special handling due to debug
99 * options set. This moves slab handling out of
100 * the fast path and disables lockless freelists.
103 #define FROZEN (1 << PG_active)
105 #ifdef CONFIG_SLUB_DEBUG
106 #define SLABDEBUG (1 << PG_error)
107 #else
108 #define SLABDEBUG 0
109 #endif
111 static inline int SlabFrozen(struct page *page)
113 return page->flags & FROZEN;
116 static inline void SetSlabFrozen(struct page *page)
118 page->flags |= FROZEN;
121 static inline void ClearSlabFrozen(struct page *page)
123 page->flags &= ~FROZEN;
126 static inline int SlabDebug(struct page *page)
128 return page->flags & SLABDEBUG;
131 static inline void SetSlabDebug(struct page *page)
133 page->flags |= SLABDEBUG;
136 static inline void ClearSlabDebug(struct page *page)
138 page->flags &= ~SLABDEBUG;
142 * Issues still to be resolved:
144 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
146 * - Variable sizing of the per node arrays
149 /* Enable to test recovery from slab corruption on boot */
150 #undef SLUB_RESILIENCY_TEST
152 #if PAGE_SHIFT <= 12
155 * Small page size. Make sure that we do not fragment memory
157 #define DEFAULT_MAX_ORDER 1
158 #define DEFAULT_MIN_OBJECTS 4
160 #else
163 * Large page machines are customarily able to handle larger
164 * page orders.
166 #define DEFAULT_MAX_ORDER 2
167 #define DEFAULT_MIN_OBJECTS 8
169 #endif
172 * Mininum number of partial slabs. These will be left on the partial
173 * lists even if they are empty. kmem_cache_shrink may reclaim them.
175 #define MIN_PARTIAL 5
178 * Maximum number of desirable partial slabs.
179 * The existence of more partial slabs makes kmem_cache_shrink
180 * sort the partial list by the number of objects in the.
182 #define MAX_PARTIAL 10
184 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
185 SLAB_POISON | SLAB_STORE_USER)
188 * Set of flags that will prevent slab merging
190 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
191 SLAB_TRACE | SLAB_DESTROY_BY_RCU)
193 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
194 SLAB_CACHE_DMA)
196 #ifndef ARCH_KMALLOC_MINALIGN
197 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
198 #endif
200 #ifndef ARCH_SLAB_MINALIGN
201 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
202 #endif
204 /* Internal SLUB flags */
205 #define __OBJECT_POISON 0x80000000 /* Poison object */
206 #define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */
207 #define __KMALLOC_CACHE 0x20000000 /* objects freed using kfree */
208 #define __PAGE_ALLOC_FALLBACK 0x10000000 /* Allow fallback to page alloc */
210 /* Not all arches define cache_line_size */
211 #ifndef cache_line_size
212 #define cache_line_size() L1_CACHE_BYTES
213 #endif
215 static int kmem_size = sizeof(struct kmem_cache);
217 #ifdef CONFIG_SMP
218 static struct notifier_block slab_notifier;
219 #endif
221 static enum {
222 DOWN, /* No slab functionality available */
223 PARTIAL, /* kmem_cache_open() works but kmalloc does not */
224 UP, /* Everything works but does not show up in sysfs */
225 SYSFS /* Sysfs up */
226 } slab_state = DOWN;
228 /* A list of all slab caches on the system */
229 static DECLARE_RWSEM(slub_lock);
230 static LIST_HEAD(slab_caches);
233 * Tracking user of a slab.
235 struct track {
236 void *addr; /* Called from address */
237 int cpu; /* Was running on cpu */
238 int pid; /* Pid context */
239 unsigned long when; /* When did the operation occur */
242 enum track_item { TRACK_ALLOC, TRACK_FREE };
244 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
245 static int sysfs_slab_add(struct kmem_cache *);
246 static int sysfs_slab_alias(struct kmem_cache *, const char *);
247 static void sysfs_slab_remove(struct kmem_cache *);
249 #else
250 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
251 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
252 { return 0; }
253 static inline void sysfs_slab_remove(struct kmem_cache *s)
255 kfree(s);
258 #endif
260 static inline void stat(struct kmem_cache_cpu *c, enum stat_item si)
262 #ifdef CONFIG_SLUB_STATS
263 c->stat[si]++;
264 #endif
267 /********************************************************************
268 * Core slab cache functions
269 *******************************************************************/
271 int slab_is_available(void)
273 return slab_state >= UP;
276 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
278 #ifdef CONFIG_NUMA
279 return s->node[node];
280 #else
281 return &s->local_node;
282 #endif
285 static inline struct kmem_cache_cpu *get_cpu_slab(struct kmem_cache *s, int cpu)
287 #ifdef CONFIG_SMP
288 return s->cpu_slab[cpu];
289 #else
290 return &s->cpu_slab;
291 #endif
294 /* Verify that a pointer has an address that is valid within a slab page */
295 static inline int check_valid_pointer(struct kmem_cache *s,
296 struct page *page, const void *object)
298 void *base;
300 if (!object)
301 return 1;
303 base = page_address(page);
304 if (object < base || object >= base + s->objects * s->size ||
305 (object - base) % s->size) {
306 return 0;
309 return 1;
313 * Slow version of get and set free pointer.
315 * This version requires touching the cache lines of kmem_cache which
316 * we avoid to do in the fast alloc free paths. There we obtain the offset
317 * from the page struct.
319 static inline void *get_freepointer(struct kmem_cache *s, void *object)
321 return *(void **)(object + s->offset);
324 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
326 *(void **)(object + s->offset) = fp;
329 /* Loop over all objects in a slab */
330 #define for_each_object(__p, __s, __addr) \
331 for (__p = (__addr); __p < (__addr) + (__s)->objects * (__s)->size;\
332 __p += (__s)->size)
334 /* Scan freelist */
335 #define for_each_free_object(__p, __s, __free) \
336 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
338 /* Determine object index from a given position */
339 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
341 return (p - addr) / s->size;
344 #ifdef CONFIG_SLUB_DEBUG
346 * Debug settings:
348 #ifdef CONFIG_SLUB_DEBUG_ON
349 static int slub_debug = DEBUG_DEFAULT_FLAGS;
350 #else
351 static int slub_debug;
352 #endif
354 static char *slub_debug_slabs;
357 * Object debugging
359 static void print_section(char *text, u8 *addr, unsigned int length)
361 int i, offset;
362 int newline = 1;
363 char ascii[17];
365 ascii[16] = 0;
367 for (i = 0; i < length; i++) {
368 if (newline) {
369 printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
370 newline = 0;
372 printk(KERN_CONT " %02x", addr[i]);
373 offset = i % 16;
374 ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
375 if (offset == 15) {
376 printk(KERN_CONT " %s\n", ascii);
377 newline = 1;
380 if (!newline) {
381 i %= 16;
382 while (i < 16) {
383 printk(KERN_CONT " ");
384 ascii[i] = ' ';
385 i++;
387 printk(KERN_CONT " %s\n", ascii);
391 static struct track *get_track(struct kmem_cache *s, void *object,
392 enum track_item alloc)
394 struct track *p;
396 if (s->offset)
397 p = object + s->offset + sizeof(void *);
398 else
399 p = object + s->inuse;
401 return p + alloc;
404 static void set_track(struct kmem_cache *s, void *object,
405 enum track_item alloc, void *addr)
407 struct track *p;
409 if (s->offset)
410 p = object + s->offset + sizeof(void *);
411 else
412 p = object + s->inuse;
414 p += alloc;
415 if (addr) {
416 p->addr = addr;
417 p->cpu = smp_processor_id();
418 p->pid = current ? current->pid : -1;
419 p->when = jiffies;
420 } else
421 memset(p, 0, sizeof(struct track));
424 static void init_tracking(struct kmem_cache *s, void *object)
426 if (!(s->flags & SLAB_STORE_USER))
427 return;
429 set_track(s, object, TRACK_FREE, NULL);
430 set_track(s, object, TRACK_ALLOC, NULL);
433 static void print_track(const char *s, struct track *t)
435 if (!t->addr)
436 return;
438 printk(KERN_ERR "INFO: %s in ", s);
439 __print_symbol("%s", (unsigned long)t->addr);
440 printk(" age=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid);
443 static void print_tracking(struct kmem_cache *s, void *object)
445 if (!(s->flags & SLAB_STORE_USER))
446 return;
448 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
449 print_track("Freed", get_track(s, object, TRACK_FREE));
452 static void print_page_info(struct page *page)
454 printk(KERN_ERR "INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n",
455 page, page->inuse, page->freelist, page->flags);
459 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
461 va_list args;
462 char buf[100];
464 va_start(args, fmt);
465 vsnprintf(buf, sizeof(buf), fmt, args);
466 va_end(args);
467 printk(KERN_ERR "========================================"
468 "=====================================\n");
469 printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
470 printk(KERN_ERR "----------------------------------------"
471 "-------------------------------------\n\n");
474 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
476 va_list args;
477 char buf[100];
479 va_start(args, fmt);
480 vsnprintf(buf, sizeof(buf), fmt, args);
481 va_end(args);
482 printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
485 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
487 unsigned int off; /* Offset of last byte */
488 u8 *addr = page_address(page);
490 print_tracking(s, p);
492 print_page_info(page);
494 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
495 p, p - addr, get_freepointer(s, p));
497 if (p > addr + 16)
498 print_section("Bytes b4", p - 16, 16);
500 print_section("Object", p, min(s->objsize, 128));
502 if (s->flags & SLAB_RED_ZONE)
503 print_section("Redzone", p + s->objsize,
504 s->inuse - s->objsize);
506 if (s->offset)
507 off = s->offset + sizeof(void *);
508 else
509 off = s->inuse;
511 if (s->flags & SLAB_STORE_USER)
512 off += 2 * sizeof(struct track);
514 if (off != s->size)
515 /* Beginning of the filler is the free pointer */
516 print_section("Padding", p + off, s->size - off);
518 dump_stack();
521 static void object_err(struct kmem_cache *s, struct page *page,
522 u8 *object, char *reason)
524 slab_bug(s, reason);
525 print_trailer(s, page, object);
528 static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
530 va_list args;
531 char buf[100];
533 va_start(args, fmt);
534 vsnprintf(buf, sizeof(buf), fmt, args);
535 va_end(args);
536 slab_bug(s, fmt);
537 print_page_info(page);
538 dump_stack();
541 static void init_object(struct kmem_cache *s, void *object, int active)
543 u8 *p = object;
545 if (s->flags & __OBJECT_POISON) {
546 memset(p, POISON_FREE, s->objsize - 1);
547 p[s->objsize - 1] = POISON_END;
550 if (s->flags & SLAB_RED_ZONE)
551 memset(p + s->objsize,
552 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE,
553 s->inuse - s->objsize);
556 static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
558 while (bytes) {
559 if (*start != (u8)value)
560 return start;
561 start++;
562 bytes--;
564 return NULL;
567 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
568 void *from, void *to)
570 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
571 memset(from, data, to - from);
574 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
575 u8 *object, char *what,
576 u8 *start, unsigned int value, unsigned int bytes)
578 u8 *fault;
579 u8 *end;
581 fault = check_bytes(start, value, bytes);
582 if (!fault)
583 return 1;
585 end = start + bytes;
586 while (end > fault && end[-1] == value)
587 end--;
589 slab_bug(s, "%s overwritten", what);
590 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
591 fault, end - 1, fault[0], value);
592 print_trailer(s, page, object);
594 restore_bytes(s, what, value, fault, end);
595 return 0;
599 * Object layout:
601 * object address
602 * Bytes of the object to be managed.
603 * If the freepointer may overlay the object then the free
604 * pointer is the first word of the object.
606 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
607 * 0xa5 (POISON_END)
609 * object + s->objsize
610 * Padding to reach word boundary. This is also used for Redzoning.
611 * Padding is extended by another word if Redzoning is enabled and
612 * objsize == inuse.
614 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
615 * 0xcc (RED_ACTIVE) for objects in use.
617 * object + s->inuse
618 * Meta data starts here.
620 * A. Free pointer (if we cannot overwrite object on free)
621 * B. Tracking data for SLAB_STORE_USER
622 * C. Padding to reach required alignment boundary or at mininum
623 * one word if debugging is on to be able to detect writes
624 * before the word boundary.
626 * Padding is done using 0x5a (POISON_INUSE)
628 * object + s->size
629 * Nothing is used beyond s->size.
631 * If slabcaches are merged then the objsize and inuse boundaries are mostly
632 * ignored. And therefore no slab options that rely on these boundaries
633 * may be used with merged slabcaches.
636 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
638 unsigned long off = s->inuse; /* The end of info */
640 if (s->offset)
641 /* Freepointer is placed after the object. */
642 off += sizeof(void *);
644 if (s->flags & SLAB_STORE_USER)
645 /* We also have user information there */
646 off += 2 * sizeof(struct track);
648 if (s->size == off)
649 return 1;
651 return check_bytes_and_report(s, page, p, "Object padding",
652 p + off, POISON_INUSE, s->size - off);
655 static int slab_pad_check(struct kmem_cache *s, struct page *page)
657 u8 *start;
658 u8 *fault;
659 u8 *end;
660 int length;
661 int remainder;
663 if (!(s->flags & SLAB_POISON))
664 return 1;
666 start = page_address(page);
667 end = start + (PAGE_SIZE << s->order);
668 length = s->objects * s->size;
669 remainder = end - (start + length);
670 if (!remainder)
671 return 1;
673 fault = check_bytes(start + length, POISON_INUSE, remainder);
674 if (!fault)
675 return 1;
676 while (end > fault && end[-1] == POISON_INUSE)
677 end--;
679 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
680 print_section("Padding", start, length);
682 restore_bytes(s, "slab padding", POISON_INUSE, start, end);
683 return 0;
686 static int check_object(struct kmem_cache *s, struct page *page,
687 void *object, int active)
689 u8 *p = object;
690 u8 *endobject = object + s->objsize;
692 if (s->flags & SLAB_RED_ZONE) {
693 unsigned int red =
694 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE;
696 if (!check_bytes_and_report(s, page, object, "Redzone",
697 endobject, red, s->inuse - s->objsize))
698 return 0;
699 } else {
700 if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
701 check_bytes_and_report(s, page, p, "Alignment padding",
702 endobject, POISON_INUSE, s->inuse - s->objsize);
706 if (s->flags & SLAB_POISON) {
707 if (!active && (s->flags & __OBJECT_POISON) &&
708 (!check_bytes_and_report(s, page, p, "Poison", p,
709 POISON_FREE, s->objsize - 1) ||
710 !check_bytes_and_report(s, page, p, "Poison",
711 p + s->objsize - 1, POISON_END, 1)))
712 return 0;
714 * check_pad_bytes cleans up on its own.
716 check_pad_bytes(s, page, p);
719 if (!s->offset && active)
721 * Object and freepointer overlap. Cannot check
722 * freepointer while object is allocated.
724 return 1;
726 /* Check free pointer validity */
727 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
728 object_err(s, page, p, "Freepointer corrupt");
730 * No choice but to zap it and thus loose the remainder
731 * of the free objects in this slab. May cause
732 * another error because the object count is now wrong.
734 set_freepointer(s, p, NULL);
735 return 0;
737 return 1;
740 static int check_slab(struct kmem_cache *s, struct page *page)
742 VM_BUG_ON(!irqs_disabled());
744 if (!PageSlab(page)) {
745 slab_err(s, page, "Not a valid slab page");
746 return 0;
748 if (page->inuse > s->objects) {
749 slab_err(s, page, "inuse %u > max %u",
750 s->name, page->inuse, s->objects);
751 return 0;
753 /* Slab_pad_check fixes things up after itself */
754 slab_pad_check(s, page);
755 return 1;
759 * Determine if a certain object on a page is on the freelist. Must hold the
760 * slab lock to guarantee that the chains are in a consistent state.
762 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
764 int nr = 0;
765 void *fp = page->freelist;
766 void *object = NULL;
768 while (fp && nr <= s->objects) {
769 if (fp == search)
770 return 1;
771 if (!check_valid_pointer(s, page, fp)) {
772 if (object) {
773 object_err(s, page, object,
774 "Freechain corrupt");
775 set_freepointer(s, object, NULL);
776 break;
777 } else {
778 slab_err(s, page, "Freepointer corrupt");
779 page->freelist = NULL;
780 page->inuse = s->objects;
781 slab_fix(s, "Freelist cleared");
782 return 0;
784 break;
786 object = fp;
787 fp = get_freepointer(s, object);
788 nr++;
791 if (page->inuse != s->objects - nr) {
792 slab_err(s, page, "Wrong object count. Counter is %d but "
793 "counted were %d", page->inuse, s->objects - nr);
794 page->inuse = s->objects - nr;
795 slab_fix(s, "Object count adjusted.");
797 return search == NULL;
800 static void trace(struct kmem_cache *s, struct page *page, void *object, int alloc)
802 if (s->flags & SLAB_TRACE) {
803 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
804 s->name,
805 alloc ? "alloc" : "free",
806 object, page->inuse,
807 page->freelist);
809 if (!alloc)
810 print_section("Object", (void *)object, s->objsize);
812 dump_stack();
817 * Tracking of fully allocated slabs for debugging purposes.
819 static void add_full(struct kmem_cache_node *n, struct page *page)
821 spin_lock(&n->list_lock);
822 list_add(&page->lru, &n->full);
823 spin_unlock(&n->list_lock);
826 static void remove_full(struct kmem_cache *s, struct page *page)
828 struct kmem_cache_node *n;
830 if (!(s->flags & SLAB_STORE_USER))
831 return;
833 n = get_node(s, page_to_nid(page));
835 spin_lock(&n->list_lock);
836 list_del(&page->lru);
837 spin_unlock(&n->list_lock);
840 static void setup_object_debug(struct kmem_cache *s, struct page *page,
841 void *object)
843 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
844 return;
846 init_object(s, object, 0);
847 init_tracking(s, object);
850 static int alloc_debug_processing(struct kmem_cache *s, struct page *page,
851 void *object, void *addr)
853 if (!check_slab(s, page))
854 goto bad;
856 if (!on_freelist(s, page, object)) {
857 object_err(s, page, object, "Object already allocated");
858 goto bad;
861 if (!check_valid_pointer(s, page, object)) {
862 object_err(s, page, object, "Freelist Pointer check fails");
863 goto bad;
866 if (!check_object(s, page, object, 0))
867 goto bad;
869 /* Success perform special debug activities for allocs */
870 if (s->flags & SLAB_STORE_USER)
871 set_track(s, object, TRACK_ALLOC, addr);
872 trace(s, page, object, 1);
873 init_object(s, object, 1);
874 return 1;
876 bad:
877 if (PageSlab(page)) {
879 * If this is a slab page then lets do the best we can
880 * to avoid issues in the future. Marking all objects
881 * as used avoids touching the remaining objects.
883 slab_fix(s, "Marking all objects used");
884 page->inuse = s->objects;
885 page->freelist = NULL;
887 return 0;
890 static int free_debug_processing(struct kmem_cache *s, struct page *page,
891 void *object, void *addr)
893 if (!check_slab(s, page))
894 goto fail;
896 if (!check_valid_pointer(s, page, object)) {
897 slab_err(s, page, "Invalid object pointer 0x%p", object);
898 goto fail;
901 if (on_freelist(s, page, object)) {
902 object_err(s, page, object, "Object already free");
903 goto fail;
906 if (!check_object(s, page, object, 1))
907 return 0;
909 if (unlikely(s != page->slab)) {
910 if (!PageSlab(page)) {
911 slab_err(s, page, "Attempt to free object(0x%p) "
912 "outside of slab", object);
913 } else if (!page->slab) {
914 printk(KERN_ERR
915 "SLUB <none>: no slab for object 0x%p.\n",
916 object);
917 dump_stack();
918 } else
919 object_err(s, page, object,
920 "page slab pointer corrupt.");
921 goto fail;
924 /* Special debug activities for freeing objects */
925 if (!SlabFrozen(page) && !page->freelist)
926 remove_full(s, page);
927 if (s->flags & SLAB_STORE_USER)
928 set_track(s, object, TRACK_FREE, addr);
929 trace(s, page, object, 0);
930 init_object(s, object, 0);
931 return 1;
933 fail:
934 slab_fix(s, "Object at 0x%p not freed", object);
935 return 0;
938 static int __init setup_slub_debug(char *str)
940 slub_debug = DEBUG_DEFAULT_FLAGS;
941 if (*str++ != '=' || !*str)
943 * No options specified. Switch on full debugging.
945 goto out;
947 if (*str == ',')
949 * No options but restriction on slabs. This means full
950 * debugging for slabs matching a pattern.
952 goto check_slabs;
954 slub_debug = 0;
955 if (*str == '-')
957 * Switch off all debugging measures.
959 goto out;
962 * Determine which debug features should be switched on
964 for (; *str && *str != ','; str++) {
965 switch (tolower(*str)) {
966 case 'f':
967 slub_debug |= SLAB_DEBUG_FREE;
968 break;
969 case 'z':
970 slub_debug |= SLAB_RED_ZONE;
971 break;
972 case 'p':
973 slub_debug |= SLAB_POISON;
974 break;
975 case 'u':
976 slub_debug |= SLAB_STORE_USER;
977 break;
978 case 't':
979 slub_debug |= SLAB_TRACE;
980 break;
981 default:
982 printk(KERN_ERR "slub_debug option '%c' "
983 "unknown. skipped\n", *str);
987 check_slabs:
988 if (*str == ',')
989 slub_debug_slabs = str + 1;
990 out:
991 return 1;
994 __setup("slub_debug", setup_slub_debug);
996 static unsigned long kmem_cache_flags(unsigned long objsize,
997 unsigned long flags, const char *name,
998 void (*ctor)(struct kmem_cache *, void *))
1001 * Enable debugging if selected on the kernel commandline.
1003 if (slub_debug && (!slub_debug_slabs ||
1004 strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)) == 0))
1005 flags |= slub_debug;
1007 return flags;
1009 #else
1010 static inline void setup_object_debug(struct kmem_cache *s,
1011 struct page *page, void *object) {}
1013 static inline int alloc_debug_processing(struct kmem_cache *s,
1014 struct page *page, void *object, void *addr) { return 0; }
1016 static inline int free_debug_processing(struct kmem_cache *s,
1017 struct page *page, void *object, void *addr) { return 0; }
1019 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1020 { return 1; }
1021 static inline int check_object(struct kmem_cache *s, struct page *page,
1022 void *object, int active) { return 1; }
1023 static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
1024 static inline unsigned long kmem_cache_flags(unsigned long objsize,
1025 unsigned long flags, const char *name,
1026 void (*ctor)(struct kmem_cache *, void *))
1028 return flags;
1030 #define slub_debug 0
1031 #endif
1033 * Slab allocation and freeing
1035 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1037 struct page *page;
1038 int pages = 1 << s->order;
1040 flags |= s->allocflags;
1042 if (node == -1)
1043 page = alloc_pages(flags, s->order);
1044 else
1045 page = alloc_pages_node(node, flags, s->order);
1047 if (!page)
1048 return NULL;
1050 mod_zone_page_state(page_zone(page),
1051 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1052 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1053 pages);
1055 return page;
1058 static void setup_object(struct kmem_cache *s, struct page *page,
1059 void *object)
1061 setup_object_debug(s, page, object);
1062 if (unlikely(s->ctor))
1063 s->ctor(s, object);
1066 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1068 struct page *page;
1069 struct kmem_cache_node *n;
1070 void *start;
1071 void *last;
1072 void *p;
1074 BUG_ON(flags & GFP_SLAB_BUG_MASK);
1076 page = allocate_slab(s,
1077 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1078 if (!page)
1079 goto out;
1081 n = get_node(s, page_to_nid(page));
1082 if (n)
1083 atomic_long_inc(&n->nr_slabs);
1084 page->slab = s;
1085 page->flags |= 1 << PG_slab;
1086 if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
1087 SLAB_STORE_USER | SLAB_TRACE))
1088 SetSlabDebug(page);
1090 start = page_address(page);
1092 if (unlikely(s->flags & SLAB_POISON))
1093 memset(start, POISON_INUSE, PAGE_SIZE << s->order);
1095 last = start;
1096 for_each_object(p, s, start) {
1097 setup_object(s, page, last);
1098 set_freepointer(s, last, p);
1099 last = p;
1101 setup_object(s, page, last);
1102 set_freepointer(s, last, NULL);
1104 page->freelist = start;
1105 page->inuse = 0;
1106 out:
1107 return page;
1110 static void __free_slab(struct kmem_cache *s, struct page *page)
1112 int pages = 1 << s->order;
1114 if (unlikely(SlabDebug(page))) {
1115 void *p;
1117 slab_pad_check(s, page);
1118 for_each_object(p, s, page_address(page))
1119 check_object(s, page, p, 0);
1120 ClearSlabDebug(page);
1123 mod_zone_page_state(page_zone(page),
1124 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1125 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1126 -pages);
1128 __free_pages(page, s->order);
1131 static void rcu_free_slab(struct rcu_head *h)
1133 struct page *page;
1135 page = container_of((struct list_head *)h, struct page, lru);
1136 __free_slab(page->slab, page);
1139 static void free_slab(struct kmem_cache *s, struct page *page)
1141 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1143 * RCU free overloads the RCU head over the LRU
1145 struct rcu_head *head = (void *)&page->lru;
1147 call_rcu(head, rcu_free_slab);
1148 } else
1149 __free_slab(s, page);
1152 static void discard_slab(struct kmem_cache *s, struct page *page)
1154 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1156 atomic_long_dec(&n->nr_slabs);
1157 reset_page_mapcount(page);
1158 __ClearPageSlab(page);
1159 free_slab(s, page);
1163 * Per slab locking using the pagelock
1165 static __always_inline void slab_lock(struct page *page)
1167 bit_spin_lock(PG_locked, &page->flags);
1170 static __always_inline void slab_unlock(struct page *page)
1172 __bit_spin_unlock(PG_locked, &page->flags);
1175 static __always_inline int slab_trylock(struct page *page)
1177 int rc = 1;
1179 rc = bit_spin_trylock(PG_locked, &page->flags);
1180 return rc;
1184 * Management of partially allocated slabs
1186 static void add_partial(struct kmem_cache_node *n,
1187 struct page *page, int tail)
1189 spin_lock(&n->list_lock);
1190 n->nr_partial++;
1191 if (tail)
1192 list_add_tail(&page->lru, &n->partial);
1193 else
1194 list_add(&page->lru, &n->partial);
1195 spin_unlock(&n->list_lock);
1198 static void remove_partial(struct kmem_cache *s,
1199 struct page *page)
1201 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1203 spin_lock(&n->list_lock);
1204 list_del(&page->lru);
1205 n->nr_partial--;
1206 spin_unlock(&n->list_lock);
1210 * Lock slab and remove from the partial list.
1212 * Must hold list_lock.
1214 static inline int lock_and_freeze_slab(struct kmem_cache_node *n, struct page *page)
1216 if (slab_trylock(page)) {
1217 list_del(&page->lru);
1218 n->nr_partial--;
1219 SetSlabFrozen(page);
1220 return 1;
1222 return 0;
1226 * Try to allocate a partial slab from a specific node.
1228 static struct page *get_partial_node(struct kmem_cache_node *n)
1230 struct page *page;
1233 * Racy check. If we mistakenly see no partial slabs then we
1234 * just allocate an empty slab. If we mistakenly try to get a
1235 * partial slab and there is none available then get_partials()
1236 * will return NULL.
1238 if (!n || !n->nr_partial)
1239 return NULL;
1241 spin_lock(&n->list_lock);
1242 list_for_each_entry(page, &n->partial, lru)
1243 if (lock_and_freeze_slab(n, page))
1244 goto out;
1245 page = NULL;
1246 out:
1247 spin_unlock(&n->list_lock);
1248 return page;
1252 * Get a page from somewhere. Search in increasing NUMA distances.
1254 static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
1256 #ifdef CONFIG_NUMA
1257 struct zonelist *zonelist;
1258 struct zone **z;
1259 struct page *page;
1262 * The defrag ratio allows a configuration of the tradeoffs between
1263 * inter node defragmentation and node local allocations. A lower
1264 * defrag_ratio increases the tendency to do local allocations
1265 * instead of attempting to obtain partial slabs from other nodes.
1267 * If the defrag_ratio is set to 0 then kmalloc() always
1268 * returns node local objects. If the ratio is higher then kmalloc()
1269 * may return off node objects because partial slabs are obtained
1270 * from other nodes and filled up.
1272 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1273 * defrag_ratio = 1000) then every (well almost) allocation will
1274 * first attempt to defrag slab caches on other nodes. This means
1275 * scanning over all nodes to look for partial slabs which may be
1276 * expensive if we do it every time we are trying to find a slab
1277 * with available objects.
1279 if (!s->remote_node_defrag_ratio ||
1280 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1281 return NULL;
1283 zonelist = &NODE_DATA(
1284 slab_node(current->mempolicy))->node_zonelists[gfp_zone(flags)];
1285 for (z = zonelist->zones; *z; z++) {
1286 struct kmem_cache_node *n;
1288 n = get_node(s, zone_to_nid(*z));
1290 if (n && cpuset_zone_allowed_hardwall(*z, flags) &&
1291 n->nr_partial > MIN_PARTIAL) {
1292 page = get_partial_node(n);
1293 if (page)
1294 return page;
1297 #endif
1298 return NULL;
1302 * Get a partial page, lock it and return it.
1304 static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
1306 struct page *page;
1307 int searchnode = (node == -1) ? numa_node_id() : node;
1309 page = get_partial_node(get_node(s, searchnode));
1310 if (page || (flags & __GFP_THISNODE))
1311 return page;
1313 return get_any_partial(s, flags);
1317 * Move a page back to the lists.
1319 * Must be called with the slab lock held.
1321 * On exit the slab lock will have been dropped.
1323 static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
1325 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1326 struct kmem_cache_cpu *c = get_cpu_slab(s, smp_processor_id());
1328 ClearSlabFrozen(page);
1329 if (page->inuse) {
1331 if (page->freelist) {
1332 add_partial(n, page, tail);
1333 stat(c, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
1334 } else {
1335 stat(c, DEACTIVATE_FULL);
1336 if (SlabDebug(page) && (s->flags & SLAB_STORE_USER))
1337 add_full(n, page);
1339 slab_unlock(page);
1340 } else {
1341 stat(c, DEACTIVATE_EMPTY);
1342 if (n->nr_partial < MIN_PARTIAL) {
1344 * Adding an empty slab to the partial slabs in order
1345 * to avoid page allocator overhead. This slab needs
1346 * to come after the other slabs with objects in
1347 * so that the others get filled first. That way the
1348 * size of the partial list stays small.
1350 * kmem_cache_shrink can reclaim any empty slabs from the
1351 * partial list.
1353 add_partial(n, page, 1);
1354 slab_unlock(page);
1355 } else {
1356 slab_unlock(page);
1357 stat(get_cpu_slab(s, raw_smp_processor_id()), FREE_SLAB);
1358 discard_slab(s, page);
1364 * Remove the cpu slab
1366 static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1368 struct page *page = c->page;
1369 int tail = 1;
1371 if (page->freelist)
1372 stat(c, DEACTIVATE_REMOTE_FREES);
1374 * Merge cpu freelist into slab freelist. Typically we get here
1375 * because both freelists are empty. So this is unlikely
1376 * to occur.
1378 while (unlikely(c->freelist)) {
1379 void **object;
1381 tail = 0; /* Hot objects. Put the slab first */
1383 /* Retrieve object from cpu_freelist */
1384 object = c->freelist;
1385 c->freelist = c->freelist[c->offset];
1387 /* And put onto the regular freelist */
1388 object[c->offset] = page->freelist;
1389 page->freelist = object;
1390 page->inuse--;
1392 c->page = NULL;
1393 unfreeze_slab(s, page, tail);
1396 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1398 stat(c, CPUSLAB_FLUSH);
1399 slab_lock(c->page);
1400 deactivate_slab(s, c);
1404 * Flush cpu slab.
1406 * Called from IPI handler with interrupts disabled.
1408 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
1410 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
1412 if (likely(c && c->page))
1413 flush_slab(s, c);
1416 static void flush_cpu_slab(void *d)
1418 struct kmem_cache *s = d;
1420 __flush_cpu_slab(s, smp_processor_id());
1423 static void flush_all(struct kmem_cache *s)
1425 #ifdef CONFIG_SMP
1426 on_each_cpu(flush_cpu_slab, s, 1, 1);
1427 #else
1428 unsigned long flags;
1430 local_irq_save(flags);
1431 flush_cpu_slab(s);
1432 local_irq_restore(flags);
1433 #endif
1437 * Check if the objects in a per cpu structure fit numa
1438 * locality expectations.
1440 static inline int node_match(struct kmem_cache_cpu *c, int node)
1442 #ifdef CONFIG_NUMA
1443 if (node != -1 && c->node != node)
1444 return 0;
1445 #endif
1446 return 1;
1450 * Slow path. The lockless freelist is empty or we need to perform
1451 * debugging duties.
1453 * Interrupts are disabled.
1455 * Processing is still very fast if new objects have been freed to the
1456 * regular freelist. In that case we simply take over the regular freelist
1457 * as the lockless freelist and zap the regular freelist.
1459 * If that is not working then we fall back to the partial lists. We take the
1460 * first element of the freelist as the object to allocate now and move the
1461 * rest of the freelist to the lockless freelist.
1463 * And if we were unable to get a new slab from the partial slab lists then
1464 * we need to allocate a new slab. This is the slowest path since it involves
1465 * a call to the page allocator and the setup of a new slab.
1467 static void *__slab_alloc(struct kmem_cache *s,
1468 gfp_t gfpflags, int node, void *addr, struct kmem_cache_cpu *c)
1470 void **object;
1471 struct page *new;
1473 /* We handle __GFP_ZERO in the caller */
1474 gfpflags &= ~__GFP_ZERO;
1476 if (!c->page)
1477 goto new_slab;
1479 slab_lock(c->page);
1480 if (unlikely(!node_match(c, node)))
1481 goto another_slab;
1483 stat(c, ALLOC_REFILL);
1485 load_freelist:
1486 object = c->page->freelist;
1487 if (unlikely(!object))
1488 goto another_slab;
1489 if (unlikely(SlabDebug(c->page)))
1490 goto debug;
1492 c->freelist = object[c->offset];
1493 c->page->inuse = s->objects;
1494 c->page->freelist = NULL;
1495 c->node = page_to_nid(c->page);
1496 unlock_out:
1497 slab_unlock(c->page);
1498 stat(c, ALLOC_SLOWPATH);
1499 return object;
1501 another_slab:
1502 deactivate_slab(s, c);
1504 new_slab:
1505 new = get_partial(s, gfpflags, node);
1506 if (new) {
1507 c->page = new;
1508 stat(c, ALLOC_FROM_PARTIAL);
1509 goto load_freelist;
1512 if (gfpflags & __GFP_WAIT)
1513 local_irq_enable();
1515 new = new_slab(s, gfpflags, node);
1517 if (gfpflags & __GFP_WAIT)
1518 local_irq_disable();
1520 if (new) {
1521 c = get_cpu_slab(s, smp_processor_id());
1522 stat(c, ALLOC_SLAB);
1523 if (c->page)
1524 flush_slab(s, c);
1525 slab_lock(new);
1526 SetSlabFrozen(new);
1527 c->page = new;
1528 goto load_freelist;
1532 * No memory available.
1534 * If the slab uses higher order allocs but the object is
1535 * smaller than a page size then we can fallback in emergencies
1536 * to the page allocator via kmalloc_large. The page allocator may
1537 * have failed to obtain a higher order page and we can try to
1538 * allocate a single page if the object fits into a single page.
1539 * That is only possible if certain conditions are met that are being
1540 * checked when a slab is created.
1542 if (!(gfpflags & __GFP_NORETRY) &&
1543 (s->flags & __PAGE_ALLOC_FALLBACK)) {
1544 if (gfpflags & __GFP_WAIT)
1545 local_irq_enable();
1546 object = kmalloc_large(s->objsize, gfpflags);
1547 if (gfpflags & __GFP_WAIT)
1548 local_irq_disable();
1549 return object;
1551 return NULL;
1552 debug:
1553 if (!alloc_debug_processing(s, c->page, object, addr))
1554 goto another_slab;
1556 c->page->inuse++;
1557 c->page->freelist = object[c->offset];
1558 c->node = -1;
1559 goto unlock_out;
1563 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1564 * have the fastpath folded into their functions. So no function call
1565 * overhead for requests that can be satisfied on the fastpath.
1567 * The fastpath works by first checking if the lockless freelist can be used.
1568 * If not then __slab_alloc is called for slow processing.
1570 * Otherwise we can simply pick the next object from the lockless free list.
1572 static __always_inline void *slab_alloc(struct kmem_cache *s,
1573 gfp_t gfpflags, int node, void *addr)
1575 void **object;
1576 struct kmem_cache_cpu *c;
1577 unsigned long flags;
1579 local_irq_save(flags);
1580 c = get_cpu_slab(s, smp_processor_id());
1581 if (unlikely(!c->freelist || !node_match(c, node)))
1583 object = __slab_alloc(s, gfpflags, node, addr, c);
1585 else {
1586 object = c->freelist;
1587 c->freelist = object[c->offset];
1588 stat(c, ALLOC_FASTPATH);
1590 local_irq_restore(flags);
1592 if (unlikely((gfpflags & __GFP_ZERO) && object))
1593 memset(object, 0, c->objsize);
1595 return object;
1598 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
1600 return slab_alloc(s, gfpflags, -1, __builtin_return_address(0));
1602 EXPORT_SYMBOL(kmem_cache_alloc);
1604 #ifdef CONFIG_NUMA
1605 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
1607 return slab_alloc(s, gfpflags, node, __builtin_return_address(0));
1609 EXPORT_SYMBOL(kmem_cache_alloc_node);
1610 #endif
1613 * Slow patch handling. This may still be called frequently since objects
1614 * have a longer lifetime than the cpu slabs in most processing loads.
1616 * So we still attempt to reduce cache line usage. Just take the slab
1617 * lock and free the item. If there is no additional partial page
1618 * handling required then we can return immediately.
1620 static void __slab_free(struct kmem_cache *s, struct page *page,
1621 void *x, void *addr, unsigned int offset)
1623 void *prior;
1624 void **object = (void *)x;
1625 struct kmem_cache_cpu *c;
1627 c = get_cpu_slab(s, raw_smp_processor_id());
1628 stat(c, FREE_SLOWPATH);
1629 slab_lock(page);
1631 if (unlikely(SlabDebug(page)))
1632 goto debug;
1634 checks_ok:
1635 prior = object[offset] = page->freelist;
1636 page->freelist = object;
1637 page->inuse--;
1639 if (unlikely(SlabFrozen(page))) {
1640 stat(c, FREE_FROZEN);
1641 goto out_unlock;
1644 if (unlikely(!page->inuse))
1645 goto slab_empty;
1648 * Objects left in the slab. If it was not on the partial list before
1649 * then add it.
1651 if (unlikely(!prior)) {
1652 add_partial(get_node(s, page_to_nid(page)), page, 1);
1653 stat(c, FREE_ADD_PARTIAL);
1656 out_unlock:
1657 slab_unlock(page);
1658 return;
1660 slab_empty:
1661 if (prior) {
1663 * Slab still on the partial list.
1665 remove_partial(s, page);
1666 stat(c, FREE_REMOVE_PARTIAL);
1668 slab_unlock(page);
1669 stat(c, FREE_SLAB);
1670 discard_slab(s, page);
1671 return;
1673 debug:
1674 if (!free_debug_processing(s, page, x, addr))
1675 goto out_unlock;
1676 goto checks_ok;
1680 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1681 * can perform fastpath freeing without additional function calls.
1683 * The fastpath is only possible if we are freeing to the current cpu slab
1684 * of this processor. This typically the case if we have just allocated
1685 * the item before.
1687 * If fastpath is not possible then fall back to __slab_free where we deal
1688 * with all sorts of special processing.
1690 static __always_inline void slab_free(struct kmem_cache *s,
1691 struct page *page, void *x, void *addr)
1693 void **object = (void *)x;
1694 struct kmem_cache_cpu *c;
1695 unsigned long flags;
1697 local_irq_save(flags);
1698 c = get_cpu_slab(s, smp_processor_id());
1699 debug_check_no_locks_freed(object, c->objsize);
1700 if (likely(page == c->page && c->node >= 0)) {
1701 object[c->offset] = c->freelist;
1702 c->freelist = object;
1703 stat(c, FREE_FASTPATH);
1704 } else
1705 __slab_free(s, page, x, addr, c->offset);
1707 local_irq_restore(flags);
1710 void kmem_cache_free(struct kmem_cache *s, void *x)
1712 struct page *page;
1714 page = virt_to_head_page(x);
1716 slab_free(s, page, x, __builtin_return_address(0));
1718 EXPORT_SYMBOL(kmem_cache_free);
1720 /* Figure out on which slab object the object resides */
1721 static struct page *get_object_page(const void *x)
1723 struct page *page = virt_to_head_page(x);
1725 if (!PageSlab(page))
1726 return NULL;
1728 return page;
1732 * Object placement in a slab is made very easy because we always start at
1733 * offset 0. If we tune the size of the object to the alignment then we can
1734 * get the required alignment by putting one properly sized object after
1735 * another.
1737 * Notice that the allocation order determines the sizes of the per cpu
1738 * caches. Each processor has always one slab available for allocations.
1739 * Increasing the allocation order reduces the number of times that slabs
1740 * must be moved on and off the partial lists and is therefore a factor in
1741 * locking overhead.
1745 * Mininum / Maximum order of slab pages. This influences locking overhead
1746 * and slab fragmentation. A higher order reduces the number of partial slabs
1747 * and increases the number of allocations possible without having to
1748 * take the list_lock.
1750 static int slub_min_order;
1751 static int slub_max_order = DEFAULT_MAX_ORDER;
1752 static int slub_min_objects = DEFAULT_MIN_OBJECTS;
1755 * Merge control. If this is set then no merging of slab caches will occur.
1756 * (Could be removed. This was introduced to pacify the merge skeptics.)
1758 static int slub_nomerge;
1761 * Calculate the order of allocation given an slab object size.
1763 * The order of allocation has significant impact on performance and other
1764 * system components. Generally order 0 allocations should be preferred since
1765 * order 0 does not cause fragmentation in the page allocator. Larger objects
1766 * be problematic to put into order 0 slabs because there may be too much
1767 * unused space left. We go to a higher order if more than 1/8th of the slab
1768 * would be wasted.
1770 * In order to reach satisfactory performance we must ensure that a minimum
1771 * number of objects is in one slab. Otherwise we may generate too much
1772 * activity on the partial lists which requires taking the list_lock. This is
1773 * less a concern for large slabs though which are rarely used.
1775 * slub_max_order specifies the order where we begin to stop considering the
1776 * number of objects in a slab as critical. If we reach slub_max_order then
1777 * we try to keep the page order as low as possible. So we accept more waste
1778 * of space in favor of a small page order.
1780 * Higher order allocations also allow the placement of more objects in a
1781 * slab and thereby reduce object handling overhead. If the user has
1782 * requested a higher mininum order then we start with that one instead of
1783 * the smallest order which will fit the object.
1785 static inline int slab_order(int size, int min_objects,
1786 int max_order, int fract_leftover)
1788 int order;
1789 int rem;
1790 int min_order = slub_min_order;
1792 for (order = max(min_order,
1793 fls(min_objects * size - 1) - PAGE_SHIFT);
1794 order <= max_order; order++) {
1796 unsigned long slab_size = PAGE_SIZE << order;
1798 if (slab_size < min_objects * size)
1799 continue;
1801 rem = slab_size % size;
1803 if (rem <= slab_size / fract_leftover)
1804 break;
1808 return order;
1811 static inline int calculate_order(int size)
1813 int order;
1814 int min_objects;
1815 int fraction;
1818 * Attempt to find best configuration for a slab. This
1819 * works by first attempting to generate a layout with
1820 * the best configuration and backing off gradually.
1822 * First we reduce the acceptable waste in a slab. Then
1823 * we reduce the minimum objects required in a slab.
1825 min_objects = slub_min_objects;
1826 while (min_objects > 1) {
1827 fraction = 8;
1828 while (fraction >= 4) {
1829 order = slab_order(size, min_objects,
1830 slub_max_order, fraction);
1831 if (order <= slub_max_order)
1832 return order;
1833 fraction /= 2;
1835 min_objects /= 2;
1839 * We were unable to place multiple objects in a slab. Now
1840 * lets see if we can place a single object there.
1842 order = slab_order(size, 1, slub_max_order, 1);
1843 if (order <= slub_max_order)
1844 return order;
1847 * Doh this slab cannot be placed using slub_max_order.
1849 order = slab_order(size, 1, MAX_ORDER, 1);
1850 if (order <= MAX_ORDER)
1851 return order;
1852 return -ENOSYS;
1856 * Figure out what the alignment of the objects will be.
1858 static unsigned long calculate_alignment(unsigned long flags,
1859 unsigned long align, unsigned long size)
1862 * If the user wants hardware cache aligned objects then follow that
1863 * suggestion if the object is sufficiently large.
1865 * The hardware cache alignment cannot override the specified
1866 * alignment though. If that is greater then use it.
1868 if (flags & SLAB_HWCACHE_ALIGN) {
1869 unsigned long ralign = cache_line_size();
1870 while (size <= ralign / 2)
1871 ralign /= 2;
1872 align = max(align, ralign);
1875 if (align < ARCH_SLAB_MINALIGN)
1876 align = ARCH_SLAB_MINALIGN;
1878 return ALIGN(align, sizeof(void *));
1881 static void init_kmem_cache_cpu(struct kmem_cache *s,
1882 struct kmem_cache_cpu *c)
1884 c->page = NULL;
1885 c->freelist = NULL;
1886 c->node = 0;
1887 c->offset = s->offset / sizeof(void *);
1888 c->objsize = s->objsize;
1891 static void init_kmem_cache_node(struct kmem_cache_node *n)
1893 n->nr_partial = 0;
1894 atomic_long_set(&n->nr_slabs, 0);
1895 spin_lock_init(&n->list_lock);
1896 INIT_LIST_HEAD(&n->partial);
1897 #ifdef CONFIG_SLUB_DEBUG
1898 INIT_LIST_HEAD(&n->full);
1899 #endif
1902 #ifdef CONFIG_SMP
1904 * Per cpu array for per cpu structures.
1906 * The per cpu array places all kmem_cache_cpu structures from one processor
1907 * close together meaning that it becomes possible that multiple per cpu
1908 * structures are contained in one cacheline. This may be particularly
1909 * beneficial for the kmalloc caches.
1911 * A desktop system typically has around 60-80 slabs. With 100 here we are
1912 * likely able to get per cpu structures for all caches from the array defined
1913 * here. We must be able to cover all kmalloc caches during bootstrap.
1915 * If the per cpu array is exhausted then fall back to kmalloc
1916 * of individual cachelines. No sharing is possible then.
1918 #define NR_KMEM_CACHE_CPU 100
1920 static DEFINE_PER_CPU(struct kmem_cache_cpu,
1921 kmem_cache_cpu)[NR_KMEM_CACHE_CPU];
1923 static DEFINE_PER_CPU(struct kmem_cache_cpu *, kmem_cache_cpu_free);
1924 static cpumask_t kmem_cach_cpu_free_init_once = CPU_MASK_NONE;
1926 static struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s,
1927 int cpu, gfp_t flags)
1929 struct kmem_cache_cpu *c = per_cpu(kmem_cache_cpu_free, cpu);
1931 if (c)
1932 per_cpu(kmem_cache_cpu_free, cpu) =
1933 (void *)c->freelist;
1934 else {
1935 /* Table overflow: So allocate ourselves */
1936 c = kmalloc_node(
1937 ALIGN(sizeof(struct kmem_cache_cpu), cache_line_size()),
1938 flags, cpu_to_node(cpu));
1939 if (!c)
1940 return NULL;
1943 init_kmem_cache_cpu(s, c);
1944 return c;
1947 static void free_kmem_cache_cpu(struct kmem_cache_cpu *c, int cpu)
1949 if (c < per_cpu(kmem_cache_cpu, cpu) ||
1950 c > per_cpu(kmem_cache_cpu, cpu) + NR_KMEM_CACHE_CPU) {
1951 kfree(c);
1952 return;
1954 c->freelist = (void *)per_cpu(kmem_cache_cpu_free, cpu);
1955 per_cpu(kmem_cache_cpu_free, cpu) = c;
1958 static void free_kmem_cache_cpus(struct kmem_cache *s)
1960 int cpu;
1962 for_each_online_cpu(cpu) {
1963 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
1965 if (c) {
1966 s->cpu_slab[cpu] = NULL;
1967 free_kmem_cache_cpu(c, cpu);
1972 static int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
1974 int cpu;
1976 for_each_online_cpu(cpu) {
1977 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
1979 if (c)
1980 continue;
1982 c = alloc_kmem_cache_cpu(s, cpu, flags);
1983 if (!c) {
1984 free_kmem_cache_cpus(s);
1985 return 0;
1987 s->cpu_slab[cpu] = c;
1989 return 1;
1993 * Initialize the per cpu array.
1995 static void init_alloc_cpu_cpu(int cpu)
1997 int i;
1999 if (cpu_isset(cpu, kmem_cach_cpu_free_init_once))
2000 return;
2002 for (i = NR_KMEM_CACHE_CPU - 1; i >= 0; i--)
2003 free_kmem_cache_cpu(&per_cpu(kmem_cache_cpu, cpu)[i], cpu);
2005 cpu_set(cpu, kmem_cach_cpu_free_init_once);
2008 static void __init init_alloc_cpu(void)
2010 int cpu;
2012 for_each_online_cpu(cpu)
2013 init_alloc_cpu_cpu(cpu);
2016 #else
2017 static inline void free_kmem_cache_cpus(struct kmem_cache *s) {}
2018 static inline void init_alloc_cpu(void) {}
2020 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
2022 init_kmem_cache_cpu(s, &s->cpu_slab);
2023 return 1;
2025 #endif
2027 #ifdef CONFIG_NUMA
2029 * No kmalloc_node yet so do it by hand. We know that this is the first
2030 * slab on the node for this slabcache. There are no concurrent accesses
2031 * possible.
2033 * Note that this function only works on the kmalloc_node_cache
2034 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2035 * memory on a fresh node that has no slab structures yet.
2037 static struct kmem_cache_node *early_kmem_cache_node_alloc(gfp_t gfpflags,
2038 int node)
2040 struct page *page;
2041 struct kmem_cache_node *n;
2042 unsigned long flags;
2044 BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
2046 page = new_slab(kmalloc_caches, gfpflags, node);
2048 BUG_ON(!page);
2049 if (page_to_nid(page) != node) {
2050 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2051 "node %d\n", node);
2052 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2053 "in order to be able to continue\n");
2056 n = page->freelist;
2057 BUG_ON(!n);
2058 page->freelist = get_freepointer(kmalloc_caches, n);
2059 page->inuse++;
2060 kmalloc_caches->node[node] = n;
2061 #ifdef CONFIG_SLUB_DEBUG
2062 init_object(kmalloc_caches, n, 1);
2063 init_tracking(kmalloc_caches, n);
2064 #endif
2065 init_kmem_cache_node(n);
2066 atomic_long_inc(&n->nr_slabs);
2069 * lockdep requires consistent irq usage for each lock
2070 * so even though there cannot be a race this early in
2071 * the boot sequence, we still disable irqs.
2073 local_irq_save(flags);
2074 add_partial(n, page, 0);
2075 local_irq_restore(flags);
2076 return n;
2079 static void free_kmem_cache_nodes(struct kmem_cache *s)
2081 int node;
2083 for_each_node_state(node, N_NORMAL_MEMORY) {
2084 struct kmem_cache_node *n = s->node[node];
2085 if (n && n != &s->local_node)
2086 kmem_cache_free(kmalloc_caches, n);
2087 s->node[node] = NULL;
2091 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2093 int node;
2094 int local_node;
2096 if (slab_state >= UP)
2097 local_node = page_to_nid(virt_to_page(s));
2098 else
2099 local_node = 0;
2101 for_each_node_state(node, N_NORMAL_MEMORY) {
2102 struct kmem_cache_node *n;
2104 if (local_node == node)
2105 n = &s->local_node;
2106 else {
2107 if (slab_state == DOWN) {
2108 n = early_kmem_cache_node_alloc(gfpflags,
2109 node);
2110 continue;
2112 n = kmem_cache_alloc_node(kmalloc_caches,
2113 gfpflags, node);
2115 if (!n) {
2116 free_kmem_cache_nodes(s);
2117 return 0;
2121 s->node[node] = n;
2122 init_kmem_cache_node(n);
2124 return 1;
2126 #else
2127 static void free_kmem_cache_nodes(struct kmem_cache *s)
2131 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2133 init_kmem_cache_node(&s->local_node);
2134 return 1;
2136 #endif
2139 * calculate_sizes() determines the order and the distribution of data within
2140 * a slab object.
2142 static int calculate_sizes(struct kmem_cache *s)
2144 unsigned long flags = s->flags;
2145 unsigned long size = s->objsize;
2146 unsigned long align = s->align;
2149 * Round up object size to the next word boundary. We can only
2150 * place the free pointer at word boundaries and this determines
2151 * the possible location of the free pointer.
2153 size = ALIGN(size, sizeof(void *));
2155 #ifdef CONFIG_SLUB_DEBUG
2157 * Determine if we can poison the object itself. If the user of
2158 * the slab may touch the object after free or before allocation
2159 * then we should never poison the object itself.
2161 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2162 !s->ctor)
2163 s->flags |= __OBJECT_POISON;
2164 else
2165 s->flags &= ~__OBJECT_POISON;
2169 * If we are Redzoning then check if there is some space between the
2170 * end of the object and the free pointer. If not then add an
2171 * additional word to have some bytes to store Redzone information.
2173 if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2174 size += sizeof(void *);
2175 #endif
2178 * With that we have determined the number of bytes in actual use
2179 * by the object. This is the potential offset to the free pointer.
2181 s->inuse = size;
2183 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2184 s->ctor)) {
2186 * Relocate free pointer after the object if it is not
2187 * permitted to overwrite the first word of the object on
2188 * kmem_cache_free.
2190 * This is the case if we do RCU, have a constructor or
2191 * destructor or are poisoning the objects.
2193 s->offset = size;
2194 size += sizeof(void *);
2197 #ifdef CONFIG_SLUB_DEBUG
2198 if (flags & SLAB_STORE_USER)
2200 * Need to store information about allocs and frees after
2201 * the object.
2203 size += 2 * sizeof(struct track);
2205 if (flags & SLAB_RED_ZONE)
2207 * Add some empty padding so that we can catch
2208 * overwrites from earlier objects rather than let
2209 * tracking information or the free pointer be
2210 * corrupted if an user writes before the start
2211 * of the object.
2213 size += sizeof(void *);
2214 #endif
2217 * Determine the alignment based on various parameters that the
2218 * user specified and the dynamic determination of cache line size
2219 * on bootup.
2221 align = calculate_alignment(flags, align, s->objsize);
2224 * SLUB stores one object immediately after another beginning from
2225 * offset 0. In order to align the objects we have to simply size
2226 * each object to conform to the alignment.
2228 size = ALIGN(size, align);
2229 s->size = size;
2231 if ((flags & __KMALLOC_CACHE) &&
2232 PAGE_SIZE / size < slub_min_objects) {
2234 * Kmalloc cache that would not have enough objects in
2235 * an order 0 page. Kmalloc slabs can fallback to
2236 * page allocator order 0 allocs so take a reasonably large
2237 * order that will allows us a good number of objects.
2239 s->order = max(slub_max_order, PAGE_ALLOC_COSTLY_ORDER);
2240 s->flags |= __PAGE_ALLOC_FALLBACK;
2241 s->allocflags |= __GFP_NOWARN;
2242 } else
2243 s->order = calculate_order(size);
2245 if (s->order < 0)
2246 return 0;
2248 s->allocflags = 0;
2249 if (s->order)
2250 s->allocflags |= __GFP_COMP;
2252 if (s->flags & SLAB_CACHE_DMA)
2253 s->allocflags |= SLUB_DMA;
2255 if (s->flags & SLAB_RECLAIM_ACCOUNT)
2256 s->allocflags |= __GFP_RECLAIMABLE;
2259 * Determine the number of objects per slab
2261 s->objects = (PAGE_SIZE << s->order) / size;
2263 return !!s->objects;
2267 static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
2268 const char *name, size_t size,
2269 size_t align, unsigned long flags,
2270 void (*ctor)(struct kmem_cache *, void *))
2272 memset(s, 0, kmem_size);
2273 s->name = name;
2274 s->ctor = ctor;
2275 s->objsize = size;
2276 s->align = align;
2277 s->flags = kmem_cache_flags(size, flags, name, ctor);
2279 if (!calculate_sizes(s))
2280 goto error;
2282 s->refcount = 1;
2283 #ifdef CONFIG_NUMA
2284 s->remote_node_defrag_ratio = 100;
2285 #endif
2286 if (!init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
2287 goto error;
2289 if (alloc_kmem_cache_cpus(s, gfpflags & ~SLUB_DMA))
2290 return 1;
2291 free_kmem_cache_nodes(s);
2292 error:
2293 if (flags & SLAB_PANIC)
2294 panic("Cannot create slab %s size=%lu realsize=%u "
2295 "order=%u offset=%u flags=%lx\n",
2296 s->name, (unsigned long)size, s->size, s->order,
2297 s->offset, flags);
2298 return 0;
2302 * Check if a given pointer is valid
2304 int kmem_ptr_validate(struct kmem_cache *s, const void *object)
2306 struct page *page;
2308 page = get_object_page(object);
2310 if (!page || s != page->slab)
2311 /* No slab or wrong slab */
2312 return 0;
2314 if (!check_valid_pointer(s, page, object))
2315 return 0;
2318 * We could also check if the object is on the slabs freelist.
2319 * But this would be too expensive and it seems that the main
2320 * purpose of kmem_ptr_valid() is to check if the object belongs
2321 * to a certain slab.
2323 return 1;
2325 EXPORT_SYMBOL(kmem_ptr_validate);
2328 * Determine the size of a slab object
2330 unsigned int kmem_cache_size(struct kmem_cache *s)
2332 return s->objsize;
2334 EXPORT_SYMBOL(kmem_cache_size);
2336 const char *kmem_cache_name(struct kmem_cache *s)
2338 return s->name;
2340 EXPORT_SYMBOL(kmem_cache_name);
2343 * Attempt to free all slabs on a node. Return the number of slabs we
2344 * were unable to free.
2346 static int free_list(struct kmem_cache *s, struct kmem_cache_node *n,
2347 struct list_head *list)
2349 int slabs_inuse = 0;
2350 unsigned long flags;
2351 struct page *page, *h;
2353 spin_lock_irqsave(&n->list_lock, flags);
2354 list_for_each_entry_safe(page, h, list, lru)
2355 if (!page->inuse) {
2356 list_del(&page->lru);
2357 discard_slab(s, page);
2358 } else
2359 slabs_inuse++;
2360 spin_unlock_irqrestore(&n->list_lock, flags);
2361 return slabs_inuse;
2365 * Release all resources used by a slab cache.
2367 static inline int kmem_cache_close(struct kmem_cache *s)
2369 int node;
2371 flush_all(s);
2373 /* Attempt to free all objects */
2374 free_kmem_cache_cpus(s);
2375 for_each_node_state(node, N_NORMAL_MEMORY) {
2376 struct kmem_cache_node *n = get_node(s, node);
2378 n->nr_partial -= free_list(s, n, &n->partial);
2379 if (atomic_long_read(&n->nr_slabs))
2380 return 1;
2382 free_kmem_cache_nodes(s);
2383 return 0;
2387 * Close a cache and release the kmem_cache structure
2388 * (must be used for caches created using kmem_cache_create)
2390 void kmem_cache_destroy(struct kmem_cache *s)
2392 down_write(&slub_lock);
2393 s->refcount--;
2394 if (!s->refcount) {
2395 list_del(&s->list);
2396 up_write(&slub_lock);
2397 if (kmem_cache_close(s))
2398 WARN_ON(1);
2399 sysfs_slab_remove(s);
2400 } else
2401 up_write(&slub_lock);
2403 EXPORT_SYMBOL(kmem_cache_destroy);
2405 /********************************************************************
2406 * Kmalloc subsystem
2407 *******************************************************************/
2409 struct kmem_cache kmalloc_caches[PAGE_SHIFT + 1] __cacheline_aligned;
2410 EXPORT_SYMBOL(kmalloc_caches);
2412 #ifdef CONFIG_ZONE_DMA
2413 static struct kmem_cache *kmalloc_caches_dma[PAGE_SHIFT + 1];
2414 #endif
2416 static int __init setup_slub_min_order(char *str)
2418 get_option(&str, &slub_min_order);
2420 return 1;
2423 __setup("slub_min_order=", setup_slub_min_order);
2425 static int __init setup_slub_max_order(char *str)
2427 get_option(&str, &slub_max_order);
2429 return 1;
2432 __setup("slub_max_order=", setup_slub_max_order);
2434 static int __init setup_slub_min_objects(char *str)
2436 get_option(&str, &slub_min_objects);
2438 return 1;
2441 __setup("slub_min_objects=", setup_slub_min_objects);
2443 static int __init setup_slub_nomerge(char *str)
2445 slub_nomerge = 1;
2446 return 1;
2449 __setup("slub_nomerge", setup_slub_nomerge);
2451 static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
2452 const char *name, int size, gfp_t gfp_flags)
2454 unsigned int flags = 0;
2456 if (gfp_flags & SLUB_DMA)
2457 flags = SLAB_CACHE_DMA;
2459 down_write(&slub_lock);
2460 if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
2461 flags | __KMALLOC_CACHE, NULL))
2462 goto panic;
2464 list_add(&s->list, &slab_caches);
2465 up_write(&slub_lock);
2466 if (sysfs_slab_add(s))
2467 goto panic;
2468 return s;
2470 panic:
2471 panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
2474 #ifdef CONFIG_ZONE_DMA
2476 static void sysfs_add_func(struct work_struct *w)
2478 struct kmem_cache *s;
2480 down_write(&slub_lock);
2481 list_for_each_entry(s, &slab_caches, list) {
2482 if (s->flags & __SYSFS_ADD_DEFERRED) {
2483 s->flags &= ~__SYSFS_ADD_DEFERRED;
2484 sysfs_slab_add(s);
2487 up_write(&slub_lock);
2490 static DECLARE_WORK(sysfs_add_work, sysfs_add_func);
2492 static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
2494 struct kmem_cache *s;
2495 char *text;
2496 size_t realsize;
2498 s = kmalloc_caches_dma[index];
2499 if (s)
2500 return s;
2502 /* Dynamically create dma cache */
2503 if (flags & __GFP_WAIT)
2504 down_write(&slub_lock);
2505 else {
2506 if (!down_write_trylock(&slub_lock))
2507 goto out;
2510 if (kmalloc_caches_dma[index])
2511 goto unlock_out;
2513 realsize = kmalloc_caches[index].objsize;
2514 text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
2515 (unsigned int)realsize);
2516 s = kmalloc(kmem_size, flags & ~SLUB_DMA);
2518 if (!s || !text || !kmem_cache_open(s, flags, text,
2519 realsize, ARCH_KMALLOC_MINALIGN,
2520 SLAB_CACHE_DMA|__SYSFS_ADD_DEFERRED, NULL)) {
2521 kfree(s);
2522 kfree(text);
2523 goto unlock_out;
2526 list_add(&s->list, &slab_caches);
2527 kmalloc_caches_dma[index] = s;
2529 schedule_work(&sysfs_add_work);
2531 unlock_out:
2532 up_write(&slub_lock);
2533 out:
2534 return kmalloc_caches_dma[index];
2536 #endif
2539 * Conversion table for small slabs sizes / 8 to the index in the
2540 * kmalloc array. This is necessary for slabs < 192 since we have non power
2541 * of two cache sizes there. The size of larger slabs can be determined using
2542 * fls.
2544 static s8 size_index[24] = {
2545 3, /* 8 */
2546 4, /* 16 */
2547 5, /* 24 */
2548 5, /* 32 */
2549 6, /* 40 */
2550 6, /* 48 */
2551 6, /* 56 */
2552 6, /* 64 */
2553 1, /* 72 */
2554 1, /* 80 */
2555 1, /* 88 */
2556 1, /* 96 */
2557 7, /* 104 */
2558 7, /* 112 */
2559 7, /* 120 */
2560 7, /* 128 */
2561 2, /* 136 */
2562 2, /* 144 */
2563 2, /* 152 */
2564 2, /* 160 */
2565 2, /* 168 */
2566 2, /* 176 */
2567 2, /* 184 */
2568 2 /* 192 */
2571 static struct kmem_cache *get_slab(size_t size, gfp_t flags)
2573 int index;
2575 if (size <= 192) {
2576 if (!size)
2577 return ZERO_SIZE_PTR;
2579 index = size_index[(size - 1) / 8];
2580 } else
2581 index = fls(size - 1);
2583 #ifdef CONFIG_ZONE_DMA
2584 if (unlikely((flags & SLUB_DMA)))
2585 return dma_kmalloc_cache(index, flags);
2587 #endif
2588 return &kmalloc_caches[index];
2591 void *__kmalloc(size_t size, gfp_t flags)
2593 struct kmem_cache *s;
2595 if (unlikely(size > PAGE_SIZE))
2596 return kmalloc_large(size, flags);
2598 s = get_slab(size, flags);
2600 if (unlikely(ZERO_OR_NULL_PTR(s)))
2601 return s;
2603 return slab_alloc(s, flags, -1, __builtin_return_address(0));
2605 EXPORT_SYMBOL(__kmalloc);
2607 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
2609 struct page *page = alloc_pages_node(node, flags | __GFP_COMP,
2610 get_order(size));
2612 if (page)
2613 return page_address(page);
2614 else
2615 return NULL;
2618 #ifdef CONFIG_NUMA
2619 void *__kmalloc_node(size_t size, gfp_t flags, int node)
2621 struct kmem_cache *s;
2623 if (unlikely(size > PAGE_SIZE))
2624 return kmalloc_large_node(size, flags, node);
2626 s = get_slab(size, flags);
2628 if (unlikely(ZERO_OR_NULL_PTR(s)))
2629 return s;
2631 return slab_alloc(s, flags, node, __builtin_return_address(0));
2633 EXPORT_SYMBOL(__kmalloc_node);
2634 #endif
2636 size_t ksize(const void *object)
2638 struct page *page;
2639 struct kmem_cache *s;
2641 if (unlikely(object == ZERO_SIZE_PTR))
2642 return 0;
2644 page = virt_to_head_page(object);
2646 if (unlikely(!PageSlab(page)))
2647 return PAGE_SIZE << compound_order(page);
2649 s = page->slab;
2651 #ifdef CONFIG_SLUB_DEBUG
2653 * Debugging requires use of the padding between object
2654 * and whatever may come after it.
2656 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
2657 return s->objsize;
2659 #endif
2661 * If we have the need to store the freelist pointer
2662 * back there or track user information then we can
2663 * only use the space before that information.
2665 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
2666 return s->inuse;
2668 * Else we can use all the padding etc for the allocation
2670 return s->size;
2672 EXPORT_SYMBOL(ksize);
2674 void kfree(const void *x)
2676 struct page *page;
2677 void *object = (void *)x;
2679 if (unlikely(ZERO_OR_NULL_PTR(x)))
2680 return;
2682 page = virt_to_head_page(x);
2683 if (unlikely(!PageSlab(page))) {
2684 put_page(page);
2685 return;
2687 slab_free(page->slab, page, object, __builtin_return_address(0));
2689 EXPORT_SYMBOL(kfree);
2691 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SLABINFO)
2692 static unsigned long count_partial(struct kmem_cache_node *n)
2694 unsigned long flags;
2695 unsigned long x = 0;
2696 struct page *page;
2698 spin_lock_irqsave(&n->list_lock, flags);
2699 list_for_each_entry(page, &n->partial, lru)
2700 x += page->inuse;
2701 spin_unlock_irqrestore(&n->list_lock, flags);
2702 return x;
2704 #endif
2707 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2708 * the remaining slabs by the number of items in use. The slabs with the
2709 * most items in use come first. New allocations will then fill those up
2710 * and thus they can be removed from the partial lists.
2712 * The slabs with the least items are placed last. This results in them
2713 * being allocated from last increasing the chance that the last objects
2714 * are freed in them.
2716 int kmem_cache_shrink(struct kmem_cache *s)
2718 int node;
2719 int i;
2720 struct kmem_cache_node *n;
2721 struct page *page;
2722 struct page *t;
2723 struct list_head *slabs_by_inuse =
2724 kmalloc(sizeof(struct list_head) * s->objects, GFP_KERNEL);
2725 unsigned long flags;
2727 if (!slabs_by_inuse)
2728 return -ENOMEM;
2730 flush_all(s);
2731 for_each_node_state(node, N_NORMAL_MEMORY) {
2732 n = get_node(s, node);
2734 if (!n->nr_partial)
2735 continue;
2737 for (i = 0; i < s->objects; i++)
2738 INIT_LIST_HEAD(slabs_by_inuse + i);
2740 spin_lock_irqsave(&n->list_lock, flags);
2743 * Build lists indexed by the items in use in each slab.
2745 * Note that concurrent frees may occur while we hold the
2746 * list_lock. page->inuse here is the upper limit.
2748 list_for_each_entry_safe(page, t, &n->partial, lru) {
2749 if (!page->inuse && slab_trylock(page)) {
2751 * Must hold slab lock here because slab_free
2752 * may have freed the last object and be
2753 * waiting to release the slab.
2755 list_del(&page->lru);
2756 n->nr_partial--;
2757 slab_unlock(page);
2758 discard_slab(s, page);
2759 } else {
2760 list_move(&page->lru,
2761 slabs_by_inuse + page->inuse);
2766 * Rebuild the partial list with the slabs filled up most
2767 * first and the least used slabs at the end.
2769 for (i = s->objects - 1; i >= 0; i--)
2770 list_splice(slabs_by_inuse + i, n->partial.prev);
2772 spin_unlock_irqrestore(&n->list_lock, flags);
2775 kfree(slabs_by_inuse);
2776 return 0;
2778 EXPORT_SYMBOL(kmem_cache_shrink);
2780 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
2781 static int slab_mem_going_offline_callback(void *arg)
2783 struct kmem_cache *s;
2785 down_read(&slub_lock);
2786 list_for_each_entry(s, &slab_caches, list)
2787 kmem_cache_shrink(s);
2788 up_read(&slub_lock);
2790 return 0;
2793 static void slab_mem_offline_callback(void *arg)
2795 struct kmem_cache_node *n;
2796 struct kmem_cache *s;
2797 struct memory_notify *marg = arg;
2798 int offline_node;
2800 offline_node = marg->status_change_nid;
2803 * If the node still has available memory. we need kmem_cache_node
2804 * for it yet.
2806 if (offline_node < 0)
2807 return;
2809 down_read(&slub_lock);
2810 list_for_each_entry(s, &slab_caches, list) {
2811 n = get_node(s, offline_node);
2812 if (n) {
2814 * if n->nr_slabs > 0, slabs still exist on the node
2815 * that is going down. We were unable to free them,
2816 * and offline_pages() function shoudn't call this
2817 * callback. So, we must fail.
2819 BUG_ON(atomic_long_read(&n->nr_slabs));
2821 s->node[offline_node] = NULL;
2822 kmem_cache_free(kmalloc_caches, n);
2825 up_read(&slub_lock);
2828 static int slab_mem_going_online_callback(void *arg)
2830 struct kmem_cache_node *n;
2831 struct kmem_cache *s;
2832 struct memory_notify *marg = arg;
2833 int nid = marg->status_change_nid;
2834 int ret = 0;
2837 * If the node's memory is already available, then kmem_cache_node is
2838 * already created. Nothing to do.
2840 if (nid < 0)
2841 return 0;
2844 * We are bringing a node online. No memory is availabe yet. We must
2845 * allocate a kmem_cache_node structure in order to bring the node
2846 * online.
2848 down_read(&slub_lock);
2849 list_for_each_entry(s, &slab_caches, list) {
2851 * XXX: kmem_cache_alloc_node will fallback to other nodes
2852 * since memory is not yet available from the node that
2853 * is brought up.
2855 n = kmem_cache_alloc(kmalloc_caches, GFP_KERNEL);
2856 if (!n) {
2857 ret = -ENOMEM;
2858 goto out;
2860 init_kmem_cache_node(n);
2861 s->node[nid] = n;
2863 out:
2864 up_read(&slub_lock);
2865 return ret;
2868 static int slab_memory_callback(struct notifier_block *self,
2869 unsigned long action, void *arg)
2871 int ret = 0;
2873 switch (action) {
2874 case MEM_GOING_ONLINE:
2875 ret = slab_mem_going_online_callback(arg);
2876 break;
2877 case MEM_GOING_OFFLINE:
2878 ret = slab_mem_going_offline_callback(arg);
2879 break;
2880 case MEM_OFFLINE:
2881 case MEM_CANCEL_ONLINE:
2882 slab_mem_offline_callback(arg);
2883 break;
2884 case MEM_ONLINE:
2885 case MEM_CANCEL_OFFLINE:
2886 break;
2889 ret = notifier_from_errno(ret);
2890 return ret;
2893 #endif /* CONFIG_MEMORY_HOTPLUG */
2895 /********************************************************************
2896 * Basic setup of slabs
2897 *******************************************************************/
2899 void __init kmem_cache_init(void)
2901 int i;
2902 int caches = 0;
2904 init_alloc_cpu();
2906 #ifdef CONFIG_NUMA
2908 * Must first have the slab cache available for the allocations of the
2909 * struct kmem_cache_node's. There is special bootstrap code in
2910 * kmem_cache_open for slab_state == DOWN.
2912 create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node",
2913 sizeof(struct kmem_cache_node), GFP_KERNEL);
2914 kmalloc_caches[0].refcount = -1;
2915 caches++;
2917 hotplug_memory_notifier(slab_memory_callback, 1);
2918 #endif
2920 /* Able to allocate the per node structures */
2921 slab_state = PARTIAL;
2923 /* Caches that are not of the two-to-the-power-of size */
2924 if (KMALLOC_MIN_SIZE <= 64) {
2925 create_kmalloc_cache(&kmalloc_caches[1],
2926 "kmalloc-96", 96, GFP_KERNEL);
2927 caches++;
2929 if (KMALLOC_MIN_SIZE <= 128) {
2930 create_kmalloc_cache(&kmalloc_caches[2],
2931 "kmalloc-192", 192, GFP_KERNEL);
2932 caches++;
2935 for (i = KMALLOC_SHIFT_LOW; i <= PAGE_SHIFT; i++) {
2936 create_kmalloc_cache(&kmalloc_caches[i],
2937 "kmalloc", 1 << i, GFP_KERNEL);
2938 caches++;
2943 * Patch up the size_index table if we have strange large alignment
2944 * requirements for the kmalloc array. This is only the case for
2945 * MIPS it seems. The standard arches will not generate any code here.
2947 * Largest permitted alignment is 256 bytes due to the way we
2948 * handle the index determination for the smaller caches.
2950 * Make sure that nothing crazy happens if someone starts tinkering
2951 * around with ARCH_KMALLOC_MINALIGN
2953 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
2954 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
2956 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8)
2957 size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW;
2959 slab_state = UP;
2961 /* Provide the correct kmalloc names now that the caches are up */
2962 for (i = KMALLOC_SHIFT_LOW; i <= PAGE_SHIFT; i++)
2963 kmalloc_caches[i]. name =
2964 kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i);
2966 #ifdef CONFIG_SMP
2967 register_cpu_notifier(&slab_notifier);
2968 kmem_size = offsetof(struct kmem_cache, cpu_slab) +
2969 nr_cpu_ids * sizeof(struct kmem_cache_cpu *);
2970 #else
2971 kmem_size = sizeof(struct kmem_cache);
2972 #endif
2974 printk(KERN_INFO
2975 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
2976 " CPUs=%d, Nodes=%d\n",
2977 caches, cache_line_size(),
2978 slub_min_order, slub_max_order, slub_min_objects,
2979 nr_cpu_ids, nr_node_ids);
2983 * Find a mergeable slab cache
2985 static int slab_unmergeable(struct kmem_cache *s)
2987 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
2988 return 1;
2990 if ((s->flags & __PAGE_ALLOC_FALLBACK))
2991 return 1;
2993 if (s->ctor)
2994 return 1;
2997 * We may have set a slab to be unmergeable during bootstrap.
2999 if (s->refcount < 0)
3000 return 1;
3002 return 0;
3005 static struct kmem_cache *find_mergeable(size_t size,
3006 size_t align, unsigned long flags, const char *name,
3007 void (*ctor)(struct kmem_cache *, void *))
3009 struct kmem_cache *s;
3011 if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3012 return NULL;
3014 if (ctor)
3015 return NULL;
3017 size = ALIGN(size, sizeof(void *));
3018 align = calculate_alignment(flags, align, size);
3019 size = ALIGN(size, align);
3020 flags = kmem_cache_flags(size, flags, name, NULL);
3022 list_for_each_entry(s, &slab_caches, list) {
3023 if (slab_unmergeable(s))
3024 continue;
3026 if (size > s->size)
3027 continue;
3029 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3030 continue;
3032 * Check if alignment is compatible.
3033 * Courtesy of Adrian Drzewiecki
3035 if ((s->size & ~(align - 1)) != s->size)
3036 continue;
3038 if (s->size - size >= sizeof(void *))
3039 continue;
3041 return s;
3043 return NULL;
3046 struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3047 size_t align, unsigned long flags,
3048 void (*ctor)(struct kmem_cache *, void *))
3050 struct kmem_cache *s;
3052 down_write(&slub_lock);
3053 s = find_mergeable(size, align, flags, name, ctor);
3054 if (s) {
3055 int cpu;
3057 s->refcount++;
3059 * Adjust the object sizes so that we clear
3060 * the complete object on kzalloc.
3062 s->objsize = max(s->objsize, (int)size);
3065 * And then we need to update the object size in the
3066 * per cpu structures
3068 for_each_online_cpu(cpu)
3069 get_cpu_slab(s, cpu)->objsize = s->objsize;
3071 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3072 up_write(&slub_lock);
3074 if (sysfs_slab_alias(s, name))
3075 goto err;
3076 return s;
3079 s = kmalloc(kmem_size, GFP_KERNEL);
3080 if (s) {
3081 if (kmem_cache_open(s, GFP_KERNEL, name,
3082 size, align, flags, ctor)) {
3083 list_add(&s->list, &slab_caches);
3084 up_write(&slub_lock);
3085 if (sysfs_slab_add(s))
3086 goto err;
3087 return s;
3089 kfree(s);
3091 up_write(&slub_lock);
3093 err:
3094 if (flags & SLAB_PANIC)
3095 panic("Cannot create slabcache %s\n", name);
3096 else
3097 s = NULL;
3098 return s;
3100 EXPORT_SYMBOL(kmem_cache_create);
3102 #ifdef CONFIG_SMP
3104 * Use the cpu notifier to insure that the cpu slabs are flushed when
3105 * necessary.
3107 static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3108 unsigned long action, void *hcpu)
3110 long cpu = (long)hcpu;
3111 struct kmem_cache *s;
3112 unsigned long flags;
3114 switch (action) {
3115 case CPU_UP_PREPARE:
3116 case CPU_UP_PREPARE_FROZEN:
3117 init_alloc_cpu_cpu(cpu);
3118 down_read(&slub_lock);
3119 list_for_each_entry(s, &slab_caches, list)
3120 s->cpu_slab[cpu] = alloc_kmem_cache_cpu(s, cpu,
3121 GFP_KERNEL);
3122 up_read(&slub_lock);
3123 break;
3125 case CPU_UP_CANCELED:
3126 case CPU_UP_CANCELED_FROZEN:
3127 case CPU_DEAD:
3128 case CPU_DEAD_FROZEN:
3129 down_read(&slub_lock);
3130 list_for_each_entry(s, &slab_caches, list) {
3131 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3133 local_irq_save(flags);
3134 __flush_cpu_slab(s, cpu);
3135 local_irq_restore(flags);
3136 free_kmem_cache_cpu(c, cpu);
3137 s->cpu_slab[cpu] = NULL;
3139 up_read(&slub_lock);
3140 break;
3141 default:
3142 break;
3144 return NOTIFY_OK;
3147 static struct notifier_block __cpuinitdata slab_notifier = {
3148 .notifier_call = slab_cpuup_callback
3151 #endif
3153 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller)
3155 struct kmem_cache *s;
3157 if (unlikely(size > PAGE_SIZE))
3158 return kmalloc_large(size, gfpflags);
3160 s = get_slab(size, gfpflags);
3162 if (unlikely(ZERO_OR_NULL_PTR(s)))
3163 return s;
3165 return slab_alloc(s, gfpflags, -1, caller);
3168 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3169 int node, void *caller)
3171 struct kmem_cache *s;
3173 if (unlikely(size > PAGE_SIZE))
3174 return kmalloc_large_node(size, gfpflags, node);
3176 s = get_slab(size, gfpflags);
3178 if (unlikely(ZERO_OR_NULL_PTR(s)))
3179 return s;
3181 return slab_alloc(s, gfpflags, node, caller);
3184 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
3185 static int validate_slab(struct kmem_cache *s, struct page *page,
3186 unsigned long *map)
3188 void *p;
3189 void *addr = page_address(page);
3191 if (!check_slab(s, page) ||
3192 !on_freelist(s, page, NULL))
3193 return 0;
3195 /* Now we know that a valid freelist exists */
3196 bitmap_zero(map, s->objects);
3198 for_each_free_object(p, s, page->freelist) {
3199 set_bit(slab_index(p, s, addr), map);
3200 if (!check_object(s, page, p, 0))
3201 return 0;
3204 for_each_object(p, s, addr)
3205 if (!test_bit(slab_index(p, s, addr), map))
3206 if (!check_object(s, page, p, 1))
3207 return 0;
3208 return 1;
3211 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3212 unsigned long *map)
3214 if (slab_trylock(page)) {
3215 validate_slab(s, page, map);
3216 slab_unlock(page);
3217 } else
3218 printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
3219 s->name, page);
3221 if (s->flags & DEBUG_DEFAULT_FLAGS) {
3222 if (!SlabDebug(page))
3223 printk(KERN_ERR "SLUB %s: SlabDebug not set "
3224 "on slab 0x%p\n", s->name, page);
3225 } else {
3226 if (SlabDebug(page))
3227 printk(KERN_ERR "SLUB %s: SlabDebug set on "
3228 "slab 0x%p\n", s->name, page);
3232 static int validate_slab_node(struct kmem_cache *s,
3233 struct kmem_cache_node *n, unsigned long *map)
3235 unsigned long count = 0;
3236 struct page *page;
3237 unsigned long flags;
3239 spin_lock_irqsave(&n->list_lock, flags);
3241 list_for_each_entry(page, &n->partial, lru) {
3242 validate_slab_slab(s, page, map);
3243 count++;
3245 if (count != n->nr_partial)
3246 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3247 "counter=%ld\n", s->name, count, n->nr_partial);
3249 if (!(s->flags & SLAB_STORE_USER))
3250 goto out;
3252 list_for_each_entry(page, &n->full, lru) {
3253 validate_slab_slab(s, page, map);
3254 count++;
3256 if (count != atomic_long_read(&n->nr_slabs))
3257 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3258 "counter=%ld\n", s->name, count,
3259 atomic_long_read(&n->nr_slabs));
3261 out:
3262 spin_unlock_irqrestore(&n->list_lock, flags);
3263 return count;
3266 static long validate_slab_cache(struct kmem_cache *s)
3268 int node;
3269 unsigned long count = 0;
3270 unsigned long *map = kmalloc(BITS_TO_LONGS(s->objects) *
3271 sizeof(unsigned long), GFP_KERNEL);
3273 if (!map)
3274 return -ENOMEM;
3276 flush_all(s);
3277 for_each_node_state(node, N_NORMAL_MEMORY) {
3278 struct kmem_cache_node *n = get_node(s, node);
3280 count += validate_slab_node(s, n, map);
3282 kfree(map);
3283 return count;
3286 #ifdef SLUB_RESILIENCY_TEST
3287 static void resiliency_test(void)
3289 u8 *p;
3291 printk(KERN_ERR "SLUB resiliency testing\n");
3292 printk(KERN_ERR "-----------------------\n");
3293 printk(KERN_ERR "A. Corruption after allocation\n");
3295 p = kzalloc(16, GFP_KERNEL);
3296 p[16] = 0x12;
3297 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
3298 " 0x12->0x%p\n\n", p + 16);
3300 validate_slab_cache(kmalloc_caches + 4);
3302 /* Hmmm... The next two are dangerous */
3303 p = kzalloc(32, GFP_KERNEL);
3304 p[32 + sizeof(void *)] = 0x34;
3305 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
3306 " 0x34 -> -0x%p\n", p);
3307 printk(KERN_ERR
3308 "If allocated object is overwritten then not detectable\n\n");
3310 validate_slab_cache(kmalloc_caches + 5);
3311 p = kzalloc(64, GFP_KERNEL);
3312 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
3313 *p = 0x56;
3314 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
3316 printk(KERN_ERR
3317 "If allocated object is overwritten then not detectable\n\n");
3318 validate_slab_cache(kmalloc_caches + 6);
3320 printk(KERN_ERR "\nB. Corruption after free\n");
3321 p = kzalloc(128, GFP_KERNEL);
3322 kfree(p);
3323 *p = 0x78;
3324 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
3325 validate_slab_cache(kmalloc_caches + 7);
3327 p = kzalloc(256, GFP_KERNEL);
3328 kfree(p);
3329 p[50] = 0x9a;
3330 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
3332 validate_slab_cache(kmalloc_caches + 8);
3334 p = kzalloc(512, GFP_KERNEL);
3335 kfree(p);
3336 p[512] = 0xab;
3337 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
3338 validate_slab_cache(kmalloc_caches + 9);
3340 #else
3341 static void resiliency_test(void) {};
3342 #endif
3345 * Generate lists of code addresses where slabcache objects are allocated
3346 * and freed.
3349 struct location {
3350 unsigned long count;
3351 void *addr;
3352 long long sum_time;
3353 long min_time;
3354 long max_time;
3355 long min_pid;
3356 long max_pid;
3357 cpumask_t cpus;
3358 nodemask_t nodes;
3361 struct loc_track {
3362 unsigned long max;
3363 unsigned long count;
3364 struct location *loc;
3367 static void free_loc_track(struct loc_track *t)
3369 if (t->max)
3370 free_pages((unsigned long)t->loc,
3371 get_order(sizeof(struct location) * t->max));
3374 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
3376 struct location *l;
3377 int order;
3379 order = get_order(sizeof(struct location) * max);
3381 l = (void *)__get_free_pages(flags, order);
3382 if (!l)
3383 return 0;
3385 if (t->count) {
3386 memcpy(l, t->loc, sizeof(struct location) * t->count);
3387 free_loc_track(t);
3389 t->max = max;
3390 t->loc = l;
3391 return 1;
3394 static int add_location(struct loc_track *t, struct kmem_cache *s,
3395 const struct track *track)
3397 long start, end, pos;
3398 struct location *l;
3399 void *caddr;
3400 unsigned long age = jiffies - track->when;
3402 start = -1;
3403 end = t->count;
3405 for ( ; ; ) {
3406 pos = start + (end - start + 1) / 2;
3409 * There is nothing at "end". If we end up there
3410 * we need to add something to before end.
3412 if (pos == end)
3413 break;
3415 caddr = t->loc[pos].addr;
3416 if (track->addr == caddr) {
3418 l = &t->loc[pos];
3419 l->count++;
3420 if (track->when) {
3421 l->sum_time += age;
3422 if (age < l->min_time)
3423 l->min_time = age;
3424 if (age > l->max_time)
3425 l->max_time = age;
3427 if (track->pid < l->min_pid)
3428 l->min_pid = track->pid;
3429 if (track->pid > l->max_pid)
3430 l->max_pid = track->pid;
3432 cpu_set(track->cpu, l->cpus);
3434 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3435 return 1;
3438 if (track->addr < caddr)
3439 end = pos;
3440 else
3441 start = pos;
3445 * Not found. Insert new tracking element.
3447 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
3448 return 0;
3450 l = t->loc + pos;
3451 if (pos < t->count)
3452 memmove(l + 1, l,
3453 (t->count - pos) * sizeof(struct location));
3454 t->count++;
3455 l->count = 1;
3456 l->addr = track->addr;
3457 l->sum_time = age;
3458 l->min_time = age;
3459 l->max_time = age;
3460 l->min_pid = track->pid;
3461 l->max_pid = track->pid;
3462 cpus_clear(l->cpus);
3463 cpu_set(track->cpu, l->cpus);
3464 nodes_clear(l->nodes);
3465 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3466 return 1;
3469 static void process_slab(struct loc_track *t, struct kmem_cache *s,
3470 struct page *page, enum track_item alloc)
3472 void *addr = page_address(page);
3473 DECLARE_BITMAP(map, s->objects);
3474 void *p;
3476 bitmap_zero(map, s->objects);
3477 for_each_free_object(p, s, page->freelist)
3478 set_bit(slab_index(p, s, addr), map);
3480 for_each_object(p, s, addr)
3481 if (!test_bit(slab_index(p, s, addr), map))
3482 add_location(t, s, get_track(s, p, alloc));
3485 static int list_locations(struct kmem_cache *s, char *buf,
3486 enum track_item alloc)
3488 int len = 0;
3489 unsigned long i;
3490 struct loc_track t = { 0, 0, NULL };
3491 int node;
3493 if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
3494 GFP_TEMPORARY))
3495 return sprintf(buf, "Out of memory\n");
3497 /* Push back cpu slabs */
3498 flush_all(s);
3500 for_each_node_state(node, N_NORMAL_MEMORY) {
3501 struct kmem_cache_node *n = get_node(s, node);
3502 unsigned long flags;
3503 struct page *page;
3505 if (!atomic_long_read(&n->nr_slabs))
3506 continue;
3508 spin_lock_irqsave(&n->list_lock, flags);
3509 list_for_each_entry(page, &n->partial, lru)
3510 process_slab(&t, s, page, alloc);
3511 list_for_each_entry(page, &n->full, lru)
3512 process_slab(&t, s, page, alloc);
3513 spin_unlock_irqrestore(&n->list_lock, flags);
3516 for (i = 0; i < t.count; i++) {
3517 struct location *l = &t.loc[i];
3519 if (len > PAGE_SIZE - 100)
3520 break;
3521 len += sprintf(buf + len, "%7ld ", l->count);
3523 if (l->addr)
3524 len += sprint_symbol(buf + len, (unsigned long)l->addr);
3525 else
3526 len += sprintf(buf + len, "<not-available>");
3528 if (l->sum_time != l->min_time) {
3529 unsigned long remainder;
3531 len += sprintf(buf + len, " age=%ld/%ld/%ld",
3532 l->min_time,
3533 div_long_long_rem(l->sum_time, l->count, &remainder),
3534 l->max_time);
3535 } else
3536 len += sprintf(buf + len, " age=%ld",
3537 l->min_time);
3539 if (l->min_pid != l->max_pid)
3540 len += sprintf(buf + len, " pid=%ld-%ld",
3541 l->min_pid, l->max_pid);
3542 else
3543 len += sprintf(buf + len, " pid=%ld",
3544 l->min_pid);
3546 if (num_online_cpus() > 1 && !cpus_empty(l->cpus) &&
3547 len < PAGE_SIZE - 60) {
3548 len += sprintf(buf + len, " cpus=");
3549 len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3550 l->cpus);
3553 if (num_online_nodes() > 1 && !nodes_empty(l->nodes) &&
3554 len < PAGE_SIZE - 60) {
3555 len += sprintf(buf + len, " nodes=");
3556 len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3557 l->nodes);
3560 len += sprintf(buf + len, "\n");
3563 free_loc_track(&t);
3564 if (!t.count)
3565 len += sprintf(buf, "No data\n");
3566 return len;
3569 enum slab_stat_type {
3570 SL_FULL,
3571 SL_PARTIAL,
3572 SL_CPU,
3573 SL_OBJECTS
3576 #define SO_FULL (1 << SL_FULL)
3577 #define SO_PARTIAL (1 << SL_PARTIAL)
3578 #define SO_CPU (1 << SL_CPU)
3579 #define SO_OBJECTS (1 << SL_OBJECTS)
3581 static ssize_t show_slab_objects(struct kmem_cache *s,
3582 char *buf, unsigned long flags)
3584 unsigned long total = 0;
3585 int cpu;
3586 int node;
3587 int x;
3588 unsigned long *nodes;
3589 unsigned long *per_cpu;
3591 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
3592 if (!nodes)
3593 return -ENOMEM;
3594 per_cpu = nodes + nr_node_ids;
3596 for_each_possible_cpu(cpu) {
3597 struct page *page;
3598 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3600 if (!c)
3601 continue;
3603 page = c->page;
3604 node = c->node;
3605 if (node < 0)
3606 continue;
3607 if (page) {
3608 if (flags & SO_CPU) {
3609 if (flags & SO_OBJECTS)
3610 x = page->inuse;
3611 else
3612 x = 1;
3613 total += x;
3614 nodes[node] += x;
3616 per_cpu[node]++;
3620 for_each_node_state(node, N_NORMAL_MEMORY) {
3621 struct kmem_cache_node *n = get_node(s, node);
3623 if (flags & SO_PARTIAL) {
3624 if (flags & SO_OBJECTS)
3625 x = count_partial(n);
3626 else
3627 x = n->nr_partial;
3628 total += x;
3629 nodes[node] += x;
3632 if (flags & SO_FULL) {
3633 int full_slabs = atomic_long_read(&n->nr_slabs)
3634 - per_cpu[node]
3635 - n->nr_partial;
3637 if (flags & SO_OBJECTS)
3638 x = full_slabs * s->objects;
3639 else
3640 x = full_slabs;
3641 total += x;
3642 nodes[node] += x;
3646 x = sprintf(buf, "%lu", total);
3647 #ifdef CONFIG_NUMA
3648 for_each_node_state(node, N_NORMAL_MEMORY)
3649 if (nodes[node])
3650 x += sprintf(buf + x, " N%d=%lu",
3651 node, nodes[node]);
3652 #endif
3653 kfree(nodes);
3654 return x + sprintf(buf + x, "\n");
3657 static int any_slab_objects(struct kmem_cache *s)
3659 int node;
3660 int cpu;
3662 for_each_possible_cpu(cpu) {
3663 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3665 if (c && c->page)
3666 return 1;
3669 for_each_online_node(node) {
3670 struct kmem_cache_node *n = get_node(s, node);
3672 if (!n)
3673 continue;
3675 if (n->nr_partial || atomic_long_read(&n->nr_slabs))
3676 return 1;
3678 return 0;
3681 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3682 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3684 struct slab_attribute {
3685 struct attribute attr;
3686 ssize_t (*show)(struct kmem_cache *s, char *buf);
3687 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
3690 #define SLAB_ATTR_RO(_name) \
3691 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3693 #define SLAB_ATTR(_name) \
3694 static struct slab_attribute _name##_attr = \
3695 __ATTR(_name, 0644, _name##_show, _name##_store)
3697 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
3699 return sprintf(buf, "%d\n", s->size);
3701 SLAB_ATTR_RO(slab_size);
3703 static ssize_t align_show(struct kmem_cache *s, char *buf)
3705 return sprintf(buf, "%d\n", s->align);
3707 SLAB_ATTR_RO(align);
3709 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
3711 return sprintf(buf, "%d\n", s->objsize);
3713 SLAB_ATTR_RO(object_size);
3715 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
3717 return sprintf(buf, "%d\n", s->objects);
3719 SLAB_ATTR_RO(objs_per_slab);
3721 static ssize_t order_show(struct kmem_cache *s, char *buf)
3723 return sprintf(buf, "%d\n", s->order);
3725 SLAB_ATTR_RO(order);
3727 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
3729 if (s->ctor) {
3730 int n = sprint_symbol(buf, (unsigned long)s->ctor);
3732 return n + sprintf(buf + n, "\n");
3734 return 0;
3736 SLAB_ATTR_RO(ctor);
3738 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
3740 return sprintf(buf, "%d\n", s->refcount - 1);
3742 SLAB_ATTR_RO(aliases);
3744 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
3746 return show_slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU);
3748 SLAB_ATTR_RO(slabs);
3750 static ssize_t partial_show(struct kmem_cache *s, char *buf)
3752 return show_slab_objects(s, buf, SO_PARTIAL);
3754 SLAB_ATTR_RO(partial);
3756 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
3758 return show_slab_objects(s, buf, SO_CPU);
3760 SLAB_ATTR_RO(cpu_slabs);
3762 static ssize_t objects_show(struct kmem_cache *s, char *buf)
3764 return show_slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU|SO_OBJECTS);
3766 SLAB_ATTR_RO(objects);
3768 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
3770 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
3773 static ssize_t sanity_checks_store(struct kmem_cache *s,
3774 const char *buf, size_t length)
3776 s->flags &= ~SLAB_DEBUG_FREE;
3777 if (buf[0] == '1')
3778 s->flags |= SLAB_DEBUG_FREE;
3779 return length;
3781 SLAB_ATTR(sanity_checks);
3783 static ssize_t trace_show(struct kmem_cache *s, char *buf)
3785 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
3788 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
3789 size_t length)
3791 s->flags &= ~SLAB_TRACE;
3792 if (buf[0] == '1')
3793 s->flags |= SLAB_TRACE;
3794 return length;
3796 SLAB_ATTR(trace);
3798 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
3800 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
3803 static ssize_t reclaim_account_store(struct kmem_cache *s,
3804 const char *buf, size_t length)
3806 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
3807 if (buf[0] == '1')
3808 s->flags |= SLAB_RECLAIM_ACCOUNT;
3809 return length;
3811 SLAB_ATTR(reclaim_account);
3813 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
3815 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
3817 SLAB_ATTR_RO(hwcache_align);
3819 #ifdef CONFIG_ZONE_DMA
3820 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
3822 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
3824 SLAB_ATTR_RO(cache_dma);
3825 #endif
3827 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
3829 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
3831 SLAB_ATTR_RO(destroy_by_rcu);
3833 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
3835 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
3838 static ssize_t red_zone_store(struct kmem_cache *s,
3839 const char *buf, size_t length)
3841 if (any_slab_objects(s))
3842 return -EBUSY;
3844 s->flags &= ~SLAB_RED_ZONE;
3845 if (buf[0] == '1')
3846 s->flags |= SLAB_RED_ZONE;
3847 calculate_sizes(s);
3848 return length;
3850 SLAB_ATTR(red_zone);
3852 static ssize_t poison_show(struct kmem_cache *s, char *buf)
3854 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
3857 static ssize_t poison_store(struct kmem_cache *s,
3858 const char *buf, size_t length)
3860 if (any_slab_objects(s))
3861 return -EBUSY;
3863 s->flags &= ~SLAB_POISON;
3864 if (buf[0] == '1')
3865 s->flags |= SLAB_POISON;
3866 calculate_sizes(s);
3867 return length;
3869 SLAB_ATTR(poison);
3871 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
3873 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
3876 static ssize_t store_user_store(struct kmem_cache *s,
3877 const char *buf, size_t length)
3879 if (any_slab_objects(s))
3880 return -EBUSY;
3882 s->flags &= ~SLAB_STORE_USER;
3883 if (buf[0] == '1')
3884 s->flags |= SLAB_STORE_USER;
3885 calculate_sizes(s);
3886 return length;
3888 SLAB_ATTR(store_user);
3890 static ssize_t validate_show(struct kmem_cache *s, char *buf)
3892 return 0;
3895 static ssize_t validate_store(struct kmem_cache *s,
3896 const char *buf, size_t length)
3898 int ret = -EINVAL;
3900 if (buf[0] == '1') {
3901 ret = validate_slab_cache(s);
3902 if (ret >= 0)
3903 ret = length;
3905 return ret;
3907 SLAB_ATTR(validate);
3909 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
3911 return 0;
3914 static ssize_t shrink_store(struct kmem_cache *s,
3915 const char *buf, size_t length)
3917 if (buf[0] == '1') {
3918 int rc = kmem_cache_shrink(s);
3920 if (rc)
3921 return rc;
3922 } else
3923 return -EINVAL;
3924 return length;
3926 SLAB_ATTR(shrink);
3928 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
3930 if (!(s->flags & SLAB_STORE_USER))
3931 return -ENOSYS;
3932 return list_locations(s, buf, TRACK_ALLOC);
3934 SLAB_ATTR_RO(alloc_calls);
3936 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
3938 if (!(s->flags & SLAB_STORE_USER))
3939 return -ENOSYS;
3940 return list_locations(s, buf, TRACK_FREE);
3942 SLAB_ATTR_RO(free_calls);
3944 #ifdef CONFIG_NUMA
3945 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
3947 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
3950 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
3951 const char *buf, size_t length)
3953 int n = simple_strtoul(buf, NULL, 10);
3955 if (n < 100)
3956 s->remote_node_defrag_ratio = n * 10;
3957 return length;
3959 SLAB_ATTR(remote_node_defrag_ratio);
3960 #endif
3962 #ifdef CONFIG_SLUB_STATS
3963 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
3965 unsigned long sum = 0;
3966 int cpu;
3967 int len;
3968 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
3970 if (!data)
3971 return -ENOMEM;
3973 for_each_online_cpu(cpu) {
3974 unsigned x = get_cpu_slab(s, cpu)->stat[si];
3976 data[cpu] = x;
3977 sum += x;
3980 len = sprintf(buf, "%lu", sum);
3982 for_each_online_cpu(cpu) {
3983 if (data[cpu] && len < PAGE_SIZE - 20)
3984 len += sprintf(buf + len, " c%d=%u", cpu, data[cpu]);
3986 kfree(data);
3987 return len + sprintf(buf + len, "\n");
3990 #define STAT_ATTR(si, text) \
3991 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
3993 return show_stat(s, buf, si); \
3995 SLAB_ATTR_RO(text); \
3997 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
3998 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
3999 STAT_ATTR(FREE_FASTPATH, free_fastpath);
4000 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4001 STAT_ATTR(FREE_FROZEN, free_frozen);
4002 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4003 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4004 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4005 STAT_ATTR(ALLOC_SLAB, alloc_slab);
4006 STAT_ATTR(ALLOC_REFILL, alloc_refill);
4007 STAT_ATTR(FREE_SLAB, free_slab);
4008 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4009 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4010 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4011 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4012 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4013 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4015 #endif
4017 static struct attribute *slab_attrs[] = {
4018 &slab_size_attr.attr,
4019 &object_size_attr.attr,
4020 &objs_per_slab_attr.attr,
4021 &order_attr.attr,
4022 &objects_attr.attr,
4023 &slabs_attr.attr,
4024 &partial_attr.attr,
4025 &cpu_slabs_attr.attr,
4026 &ctor_attr.attr,
4027 &aliases_attr.attr,
4028 &align_attr.attr,
4029 &sanity_checks_attr.attr,
4030 &trace_attr.attr,
4031 &hwcache_align_attr.attr,
4032 &reclaim_account_attr.attr,
4033 &destroy_by_rcu_attr.attr,
4034 &red_zone_attr.attr,
4035 &poison_attr.attr,
4036 &store_user_attr.attr,
4037 &validate_attr.attr,
4038 &shrink_attr.attr,
4039 &alloc_calls_attr.attr,
4040 &free_calls_attr.attr,
4041 #ifdef CONFIG_ZONE_DMA
4042 &cache_dma_attr.attr,
4043 #endif
4044 #ifdef CONFIG_NUMA
4045 &remote_node_defrag_ratio_attr.attr,
4046 #endif
4047 #ifdef CONFIG_SLUB_STATS
4048 &alloc_fastpath_attr.attr,
4049 &alloc_slowpath_attr.attr,
4050 &free_fastpath_attr.attr,
4051 &free_slowpath_attr.attr,
4052 &free_frozen_attr.attr,
4053 &free_add_partial_attr.attr,
4054 &free_remove_partial_attr.attr,
4055 &alloc_from_partial_attr.attr,
4056 &alloc_slab_attr.attr,
4057 &alloc_refill_attr.attr,
4058 &free_slab_attr.attr,
4059 &cpuslab_flush_attr.attr,
4060 &deactivate_full_attr.attr,
4061 &deactivate_empty_attr.attr,
4062 &deactivate_to_head_attr.attr,
4063 &deactivate_to_tail_attr.attr,
4064 &deactivate_remote_frees_attr.attr,
4065 #endif
4066 NULL
4069 static struct attribute_group slab_attr_group = {
4070 .attrs = slab_attrs,
4073 static ssize_t slab_attr_show(struct kobject *kobj,
4074 struct attribute *attr,
4075 char *buf)
4077 struct slab_attribute *attribute;
4078 struct kmem_cache *s;
4079 int err;
4081 attribute = to_slab_attr(attr);
4082 s = to_slab(kobj);
4084 if (!attribute->show)
4085 return -EIO;
4087 err = attribute->show(s, buf);
4089 return err;
4092 static ssize_t slab_attr_store(struct kobject *kobj,
4093 struct attribute *attr,
4094 const char *buf, size_t len)
4096 struct slab_attribute *attribute;
4097 struct kmem_cache *s;
4098 int err;
4100 attribute = to_slab_attr(attr);
4101 s = to_slab(kobj);
4103 if (!attribute->store)
4104 return -EIO;
4106 err = attribute->store(s, buf, len);
4108 return err;
4111 static void kmem_cache_release(struct kobject *kobj)
4113 struct kmem_cache *s = to_slab(kobj);
4115 kfree(s);
4118 static struct sysfs_ops slab_sysfs_ops = {
4119 .show = slab_attr_show,
4120 .store = slab_attr_store,
4123 static struct kobj_type slab_ktype = {
4124 .sysfs_ops = &slab_sysfs_ops,
4125 .release = kmem_cache_release
4128 static int uevent_filter(struct kset *kset, struct kobject *kobj)
4130 struct kobj_type *ktype = get_ktype(kobj);
4132 if (ktype == &slab_ktype)
4133 return 1;
4134 return 0;
4137 static struct kset_uevent_ops slab_uevent_ops = {
4138 .filter = uevent_filter,
4141 static struct kset *slab_kset;
4143 #define ID_STR_LENGTH 64
4145 /* Create a unique string id for a slab cache:
4147 * Format :[flags-]size
4149 static char *create_unique_id(struct kmem_cache *s)
4151 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
4152 char *p = name;
4154 BUG_ON(!name);
4156 *p++ = ':';
4158 * First flags affecting slabcache operations. We will only
4159 * get here for aliasable slabs so we do not need to support
4160 * too many flags. The flags here must cover all flags that
4161 * are matched during merging to guarantee that the id is
4162 * unique.
4164 if (s->flags & SLAB_CACHE_DMA)
4165 *p++ = 'd';
4166 if (s->flags & SLAB_RECLAIM_ACCOUNT)
4167 *p++ = 'a';
4168 if (s->flags & SLAB_DEBUG_FREE)
4169 *p++ = 'F';
4170 if (p != name + 1)
4171 *p++ = '-';
4172 p += sprintf(p, "%07d", s->size);
4173 BUG_ON(p > name + ID_STR_LENGTH - 1);
4174 return name;
4177 static int sysfs_slab_add(struct kmem_cache *s)
4179 int err;
4180 const char *name;
4181 int unmergeable;
4183 if (slab_state < SYSFS)
4184 /* Defer until later */
4185 return 0;
4187 unmergeable = slab_unmergeable(s);
4188 if (unmergeable) {
4190 * Slabcache can never be merged so we can use the name proper.
4191 * This is typically the case for debug situations. In that
4192 * case we can catch duplicate names easily.
4194 sysfs_remove_link(&slab_kset->kobj, s->name);
4195 name = s->name;
4196 } else {
4198 * Create a unique name for the slab as a target
4199 * for the symlinks.
4201 name = create_unique_id(s);
4204 s->kobj.kset = slab_kset;
4205 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
4206 if (err) {
4207 kobject_put(&s->kobj);
4208 return err;
4211 err = sysfs_create_group(&s->kobj, &slab_attr_group);
4212 if (err)
4213 return err;
4214 kobject_uevent(&s->kobj, KOBJ_ADD);
4215 if (!unmergeable) {
4216 /* Setup first alias */
4217 sysfs_slab_alias(s, s->name);
4218 kfree(name);
4220 return 0;
4223 static void sysfs_slab_remove(struct kmem_cache *s)
4225 kobject_uevent(&s->kobj, KOBJ_REMOVE);
4226 kobject_del(&s->kobj);
4227 kobject_put(&s->kobj);
4231 * Need to buffer aliases during bootup until sysfs becomes
4232 * available lest we loose that information.
4234 struct saved_alias {
4235 struct kmem_cache *s;
4236 const char *name;
4237 struct saved_alias *next;
4240 static struct saved_alias *alias_list;
4242 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
4244 struct saved_alias *al;
4246 if (slab_state == SYSFS) {
4248 * If we have a leftover link then remove it.
4250 sysfs_remove_link(&slab_kset->kobj, name);
4251 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
4254 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
4255 if (!al)
4256 return -ENOMEM;
4258 al->s = s;
4259 al->name = name;
4260 al->next = alias_list;
4261 alias_list = al;
4262 return 0;
4265 static int __init slab_sysfs_init(void)
4267 struct kmem_cache *s;
4268 int err;
4270 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
4271 if (!slab_kset) {
4272 printk(KERN_ERR "Cannot register slab subsystem.\n");
4273 return -ENOSYS;
4276 slab_state = SYSFS;
4278 list_for_each_entry(s, &slab_caches, list) {
4279 err = sysfs_slab_add(s);
4280 if (err)
4281 printk(KERN_ERR "SLUB: Unable to add boot slab %s"
4282 " to sysfs\n", s->name);
4285 while (alias_list) {
4286 struct saved_alias *al = alias_list;
4288 alias_list = alias_list->next;
4289 err = sysfs_slab_alias(al->s, al->name);
4290 if (err)
4291 printk(KERN_ERR "SLUB: Unable to add boot slab alias"
4292 " %s to sysfs\n", s->name);
4293 kfree(al);
4296 resiliency_test();
4297 return 0;
4300 __initcall(slab_sysfs_init);
4301 #endif
4304 * The /proc/slabinfo ABI
4306 #ifdef CONFIG_SLABINFO
4308 ssize_t slabinfo_write(struct file *file, const char __user * buffer,
4309 size_t count, loff_t *ppos)
4311 return -EINVAL;
4315 static void print_slabinfo_header(struct seq_file *m)
4317 seq_puts(m, "slabinfo - version: 2.1\n");
4318 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
4319 "<objperslab> <pagesperslab>");
4320 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
4321 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4322 seq_putc(m, '\n');
4325 static void *s_start(struct seq_file *m, loff_t *pos)
4327 loff_t n = *pos;
4329 down_read(&slub_lock);
4330 if (!n)
4331 print_slabinfo_header(m);
4333 return seq_list_start(&slab_caches, *pos);
4336 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4338 return seq_list_next(p, &slab_caches, pos);
4341 static void s_stop(struct seq_file *m, void *p)
4343 up_read(&slub_lock);
4346 static int s_show(struct seq_file *m, void *p)
4348 unsigned long nr_partials = 0;
4349 unsigned long nr_slabs = 0;
4350 unsigned long nr_inuse = 0;
4351 unsigned long nr_objs;
4352 struct kmem_cache *s;
4353 int node;
4355 s = list_entry(p, struct kmem_cache, list);
4357 for_each_online_node(node) {
4358 struct kmem_cache_node *n = get_node(s, node);
4360 if (!n)
4361 continue;
4363 nr_partials += n->nr_partial;
4364 nr_slabs += atomic_long_read(&n->nr_slabs);
4365 nr_inuse += count_partial(n);
4368 nr_objs = nr_slabs * s->objects;
4369 nr_inuse += (nr_slabs - nr_partials) * s->objects;
4371 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
4372 nr_objs, s->size, s->objects, (1 << s->order));
4373 seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
4374 seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
4375 0UL);
4376 seq_putc(m, '\n');
4377 return 0;
4380 const struct seq_operations slabinfo_op = {
4381 .start = s_start,
4382 .next = s_next,
4383 .stop = s_stop,
4384 .show = s_show,
4387 #endif /* CONFIG_SLABINFO */