kthreads: simplify migration_thread() exit path
[linux-2.6/mini2440.git] / mm / slub.c
blob4c6449310a0ef387a3307ea1baa6617451e09e84
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
9 */
11 #include <linux/mm.h>
12 #include <linux/swap.h> /* struct reclaim_state */
13 #include <linux/module.h>
14 #include <linux/bit_spinlock.h>
15 #include <linux/interrupt.h>
16 #include <linux/bitops.h>
17 #include <linux/slab.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <linux/kmemtrace.h>
21 #include <linux/kmemcheck.h>
22 #include <linux/cpu.h>
23 #include <linux/cpuset.h>
24 #include <linux/kmemleak.h>
25 #include <linux/mempolicy.h>
26 #include <linux/ctype.h>
27 #include <linux/debugobjects.h>
28 #include <linux/kallsyms.h>
29 #include <linux/memory.h>
30 #include <linux/math64.h>
31 #include <linux/fault-inject.h>
34 * Lock order:
35 * 1. slab_lock(page)
36 * 2. slab->list_lock
38 * The slab_lock protects operations on the object of a particular
39 * slab and its metadata in the page struct. If the slab lock
40 * has been taken then no allocations nor frees can be performed
41 * on the objects in the slab nor can the slab be added or removed
42 * from the partial or full lists since this would mean modifying
43 * the page_struct of the slab.
45 * The list_lock protects the partial and full list on each node and
46 * the partial slab counter. If taken then no new slabs may be added or
47 * removed from the lists nor make the number of partial slabs be modified.
48 * (Note that the total number of slabs is an atomic value that may be
49 * modified without taking the list lock).
51 * The list_lock is a centralized lock and thus we avoid taking it as
52 * much as possible. As long as SLUB does not have to handle partial
53 * slabs, operations can continue without any centralized lock. F.e.
54 * allocating a long series of objects that fill up slabs does not require
55 * the list lock.
57 * The lock order is sometimes inverted when we are trying to get a slab
58 * off a list. We take the list_lock and then look for a page on the list
59 * to use. While we do that objects in the slabs may be freed. We can
60 * only operate on the slab if we have also taken the slab_lock. So we use
61 * a slab_trylock() on the slab. If trylock was successful then no frees
62 * can occur anymore and we can use the slab for allocations etc. If the
63 * slab_trylock() does not succeed then frees are in progress in the slab and
64 * we must stay away from it for a while since we may cause a bouncing
65 * cacheline if we try to acquire the lock. So go onto the next slab.
66 * If all pages are busy then we may allocate a new slab instead of reusing
67 * a partial slab. A new slab has noone operating on it and thus there is
68 * no danger of cacheline contention.
70 * Interrupts are disabled during allocation and deallocation in order to
71 * make the slab allocator safe to use in the context of an irq. In addition
72 * interrupts are disabled to ensure that the processor does not change
73 * while handling per_cpu slabs, due to kernel preemption.
75 * SLUB assigns one slab for allocation to each processor.
76 * Allocations only occur from these slabs called cpu slabs.
78 * Slabs with free elements are kept on a partial list and during regular
79 * operations no list for full slabs is used. If an object in a full slab is
80 * freed then the slab will show up again on the partial lists.
81 * We track full slabs for debugging purposes though because otherwise we
82 * cannot scan all objects.
84 * Slabs are freed when they become empty. Teardown and setup is
85 * minimal so we rely on the page allocators per cpu caches for
86 * fast frees and allocs.
88 * Overloading of page flags that are otherwise used for LRU management.
90 * PageActive The slab is frozen and exempt from list processing.
91 * This means that the slab is dedicated to a purpose
92 * such as satisfying allocations for a specific
93 * processor. Objects may be freed in the slab while
94 * it is frozen but slab_free will then skip the usual
95 * list operations. It is up to the processor holding
96 * the slab to integrate the slab into the slab lists
97 * when the slab is no longer needed.
99 * One use of this flag is to mark slabs that are
100 * used for allocations. Then such a slab becomes a cpu
101 * slab. The cpu slab may be equipped with an additional
102 * freelist that allows lockless access to
103 * free objects in addition to the regular freelist
104 * that requires the slab lock.
106 * PageError Slab requires special handling due to debug
107 * options set. This moves slab handling out of
108 * the fast path and disables lockless freelists.
111 #ifdef CONFIG_SLUB_DEBUG
112 #define SLABDEBUG 1
113 #else
114 #define SLABDEBUG 0
115 #endif
118 * Issues still to be resolved:
120 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
122 * - Variable sizing of the per node arrays
125 /* Enable to test recovery from slab corruption on boot */
126 #undef SLUB_RESILIENCY_TEST
129 * Mininum number of partial slabs. These will be left on the partial
130 * lists even if they are empty. kmem_cache_shrink may reclaim them.
132 #define MIN_PARTIAL 5
135 * Maximum number of desirable partial slabs.
136 * The existence of more partial slabs makes kmem_cache_shrink
137 * sort the partial list by the number of objects in the.
139 #define MAX_PARTIAL 10
141 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
142 SLAB_POISON | SLAB_STORE_USER)
145 * Set of flags that will prevent slab merging
147 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
148 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE)
150 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
151 SLAB_CACHE_DMA | SLAB_NOTRACK)
153 #ifndef ARCH_KMALLOC_MINALIGN
154 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
155 #endif
157 #ifndef ARCH_SLAB_MINALIGN
158 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
159 #endif
161 #define OO_SHIFT 16
162 #define OO_MASK ((1 << OO_SHIFT) - 1)
163 #define MAX_OBJS_PER_PAGE 65535 /* since page.objects is u16 */
165 /* Internal SLUB flags */
166 #define __OBJECT_POISON 0x80000000 /* Poison object */
167 #define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */
169 static int kmem_size = sizeof(struct kmem_cache);
171 #ifdef CONFIG_SMP
172 static struct notifier_block slab_notifier;
173 #endif
175 static enum {
176 DOWN, /* No slab functionality available */
177 PARTIAL, /* kmem_cache_open() works but kmalloc does not */
178 UP, /* Everything works but does not show up in sysfs */
179 SYSFS /* Sysfs up */
180 } slab_state = DOWN;
183 * The slab allocator is initialized with interrupts disabled. Therefore, make
184 * sure early boot allocations don't accidentally enable interrupts.
186 static gfp_t slab_gfp_mask __read_mostly = SLAB_GFP_BOOT_MASK;
188 /* A list of all slab caches on the system */
189 static DECLARE_RWSEM(slub_lock);
190 static LIST_HEAD(slab_caches);
193 * Tracking user of a slab.
195 struct track {
196 unsigned long addr; /* Called from address */
197 int cpu; /* Was running on cpu */
198 int pid; /* Pid context */
199 unsigned long when; /* When did the operation occur */
202 enum track_item { TRACK_ALLOC, TRACK_FREE };
204 #ifdef CONFIG_SLUB_DEBUG
205 static int sysfs_slab_add(struct kmem_cache *);
206 static int sysfs_slab_alias(struct kmem_cache *, const char *);
207 static void sysfs_slab_remove(struct kmem_cache *);
209 #else
210 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
211 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
212 { return 0; }
213 static inline void sysfs_slab_remove(struct kmem_cache *s)
215 kfree(s);
218 #endif
220 static inline void stat(struct kmem_cache_cpu *c, enum stat_item si)
222 #ifdef CONFIG_SLUB_STATS
223 c->stat[si]++;
224 #endif
227 /********************************************************************
228 * Core slab cache functions
229 *******************************************************************/
231 int slab_is_available(void)
233 return slab_state >= UP;
236 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
238 #ifdef CONFIG_NUMA
239 return s->node[node];
240 #else
241 return &s->local_node;
242 #endif
245 static inline struct kmem_cache_cpu *get_cpu_slab(struct kmem_cache *s, int cpu)
247 #ifdef CONFIG_SMP
248 return s->cpu_slab[cpu];
249 #else
250 return &s->cpu_slab;
251 #endif
254 /* Verify that a pointer has an address that is valid within a slab page */
255 static inline int check_valid_pointer(struct kmem_cache *s,
256 struct page *page, const void *object)
258 void *base;
260 if (!object)
261 return 1;
263 base = page_address(page);
264 if (object < base || object >= base + page->objects * s->size ||
265 (object - base) % s->size) {
266 return 0;
269 return 1;
273 * Slow version of get and set free pointer.
275 * This version requires touching the cache lines of kmem_cache which
276 * we avoid to do in the fast alloc free paths. There we obtain the offset
277 * from the page struct.
279 static inline void *get_freepointer(struct kmem_cache *s, void *object)
281 return *(void **)(object + s->offset);
284 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
286 *(void **)(object + s->offset) = fp;
289 /* Loop over all objects in a slab */
290 #define for_each_object(__p, __s, __addr, __objects) \
291 for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
292 __p += (__s)->size)
294 /* Scan freelist */
295 #define for_each_free_object(__p, __s, __free) \
296 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
298 /* Determine object index from a given position */
299 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
301 return (p - addr) / s->size;
304 static inline struct kmem_cache_order_objects oo_make(int order,
305 unsigned long size)
307 struct kmem_cache_order_objects x = {
308 (order << OO_SHIFT) + (PAGE_SIZE << order) / size
311 return x;
314 static inline int oo_order(struct kmem_cache_order_objects x)
316 return x.x >> OO_SHIFT;
319 static inline int oo_objects(struct kmem_cache_order_objects x)
321 return x.x & OO_MASK;
324 #ifdef CONFIG_SLUB_DEBUG
326 * Debug settings:
328 #ifdef CONFIG_SLUB_DEBUG_ON
329 static int slub_debug = DEBUG_DEFAULT_FLAGS;
330 #else
331 static int slub_debug;
332 #endif
334 static char *slub_debug_slabs;
337 * Object debugging
339 static void print_section(char *text, u8 *addr, unsigned int length)
341 int i, offset;
342 int newline = 1;
343 char ascii[17];
345 ascii[16] = 0;
347 for (i = 0; i < length; i++) {
348 if (newline) {
349 printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
350 newline = 0;
352 printk(KERN_CONT " %02x", addr[i]);
353 offset = i % 16;
354 ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
355 if (offset == 15) {
356 printk(KERN_CONT " %s\n", ascii);
357 newline = 1;
360 if (!newline) {
361 i %= 16;
362 while (i < 16) {
363 printk(KERN_CONT " ");
364 ascii[i] = ' ';
365 i++;
367 printk(KERN_CONT " %s\n", ascii);
371 static struct track *get_track(struct kmem_cache *s, void *object,
372 enum track_item alloc)
374 struct track *p;
376 if (s->offset)
377 p = object + s->offset + sizeof(void *);
378 else
379 p = object + s->inuse;
381 return p + alloc;
384 static void set_track(struct kmem_cache *s, void *object,
385 enum track_item alloc, unsigned long addr)
387 struct track *p = get_track(s, object, alloc);
389 if (addr) {
390 p->addr = addr;
391 p->cpu = smp_processor_id();
392 p->pid = current->pid;
393 p->when = jiffies;
394 } else
395 memset(p, 0, sizeof(struct track));
398 static void init_tracking(struct kmem_cache *s, void *object)
400 if (!(s->flags & SLAB_STORE_USER))
401 return;
403 set_track(s, object, TRACK_FREE, 0UL);
404 set_track(s, object, TRACK_ALLOC, 0UL);
407 static void print_track(const char *s, struct track *t)
409 if (!t->addr)
410 return;
412 printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
413 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
416 static void print_tracking(struct kmem_cache *s, void *object)
418 if (!(s->flags & SLAB_STORE_USER))
419 return;
421 print_track("Allocated", get_track(s, object, TRACK_ALLOC));
422 print_track("Freed", get_track(s, object, TRACK_FREE));
425 static void print_page_info(struct page *page)
427 printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
428 page, page->objects, page->inuse, page->freelist, page->flags);
432 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
434 va_list args;
435 char buf[100];
437 va_start(args, fmt);
438 vsnprintf(buf, sizeof(buf), fmt, args);
439 va_end(args);
440 printk(KERN_ERR "========================================"
441 "=====================================\n");
442 printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
443 printk(KERN_ERR "----------------------------------------"
444 "-------------------------------------\n\n");
447 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
449 va_list args;
450 char buf[100];
452 va_start(args, fmt);
453 vsnprintf(buf, sizeof(buf), fmt, args);
454 va_end(args);
455 printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
458 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
460 unsigned int off; /* Offset of last byte */
461 u8 *addr = page_address(page);
463 print_tracking(s, p);
465 print_page_info(page);
467 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
468 p, p - addr, get_freepointer(s, p));
470 if (p > addr + 16)
471 print_section("Bytes b4", p - 16, 16);
473 print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE));
475 if (s->flags & SLAB_RED_ZONE)
476 print_section("Redzone", p + s->objsize,
477 s->inuse - s->objsize);
479 if (s->offset)
480 off = s->offset + sizeof(void *);
481 else
482 off = s->inuse;
484 if (s->flags & SLAB_STORE_USER)
485 off += 2 * sizeof(struct track);
487 if (off != s->size)
488 /* Beginning of the filler is the free pointer */
489 print_section("Padding", p + off, s->size - off);
491 dump_stack();
494 static void object_err(struct kmem_cache *s, struct page *page,
495 u8 *object, char *reason)
497 slab_bug(s, "%s", reason);
498 print_trailer(s, page, object);
501 static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
503 va_list args;
504 char buf[100];
506 va_start(args, fmt);
507 vsnprintf(buf, sizeof(buf), fmt, args);
508 va_end(args);
509 slab_bug(s, "%s", buf);
510 print_page_info(page);
511 dump_stack();
514 static void init_object(struct kmem_cache *s, void *object, int active)
516 u8 *p = object;
518 if (s->flags & __OBJECT_POISON) {
519 memset(p, POISON_FREE, s->objsize - 1);
520 p[s->objsize - 1] = POISON_END;
523 if (s->flags & SLAB_RED_ZONE)
524 memset(p + s->objsize,
525 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE,
526 s->inuse - s->objsize);
529 static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
531 while (bytes) {
532 if (*start != (u8)value)
533 return start;
534 start++;
535 bytes--;
537 return NULL;
540 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
541 void *from, void *to)
543 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
544 memset(from, data, to - from);
547 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
548 u8 *object, char *what,
549 u8 *start, unsigned int value, unsigned int bytes)
551 u8 *fault;
552 u8 *end;
554 fault = check_bytes(start, value, bytes);
555 if (!fault)
556 return 1;
558 end = start + bytes;
559 while (end > fault && end[-1] == value)
560 end--;
562 slab_bug(s, "%s overwritten", what);
563 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
564 fault, end - 1, fault[0], value);
565 print_trailer(s, page, object);
567 restore_bytes(s, what, value, fault, end);
568 return 0;
572 * Object layout:
574 * object address
575 * Bytes of the object to be managed.
576 * If the freepointer may overlay the object then the free
577 * pointer is the first word of the object.
579 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
580 * 0xa5 (POISON_END)
582 * object + s->objsize
583 * Padding to reach word boundary. This is also used for Redzoning.
584 * Padding is extended by another word if Redzoning is enabled and
585 * objsize == inuse.
587 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
588 * 0xcc (RED_ACTIVE) for objects in use.
590 * object + s->inuse
591 * Meta data starts here.
593 * A. Free pointer (if we cannot overwrite object on free)
594 * B. Tracking data for SLAB_STORE_USER
595 * C. Padding to reach required alignment boundary or at mininum
596 * one word if debugging is on to be able to detect writes
597 * before the word boundary.
599 * Padding is done using 0x5a (POISON_INUSE)
601 * object + s->size
602 * Nothing is used beyond s->size.
604 * If slabcaches are merged then the objsize and inuse boundaries are mostly
605 * ignored. And therefore no slab options that rely on these boundaries
606 * may be used with merged slabcaches.
609 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
611 unsigned long off = s->inuse; /* The end of info */
613 if (s->offset)
614 /* Freepointer is placed after the object. */
615 off += sizeof(void *);
617 if (s->flags & SLAB_STORE_USER)
618 /* We also have user information there */
619 off += 2 * sizeof(struct track);
621 if (s->size == off)
622 return 1;
624 return check_bytes_and_report(s, page, p, "Object padding",
625 p + off, POISON_INUSE, s->size - off);
628 /* Check the pad bytes at the end of a slab page */
629 static int slab_pad_check(struct kmem_cache *s, struct page *page)
631 u8 *start;
632 u8 *fault;
633 u8 *end;
634 int length;
635 int remainder;
637 if (!(s->flags & SLAB_POISON))
638 return 1;
640 start = page_address(page);
641 length = (PAGE_SIZE << compound_order(page));
642 end = start + length;
643 remainder = length % s->size;
644 if (!remainder)
645 return 1;
647 fault = check_bytes(end - remainder, POISON_INUSE, remainder);
648 if (!fault)
649 return 1;
650 while (end > fault && end[-1] == POISON_INUSE)
651 end--;
653 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
654 print_section("Padding", end - remainder, remainder);
656 restore_bytes(s, "slab padding", POISON_INUSE, start, end);
657 return 0;
660 static int check_object(struct kmem_cache *s, struct page *page,
661 void *object, int active)
663 u8 *p = object;
664 u8 *endobject = object + s->objsize;
666 if (s->flags & SLAB_RED_ZONE) {
667 unsigned int red =
668 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE;
670 if (!check_bytes_and_report(s, page, object, "Redzone",
671 endobject, red, s->inuse - s->objsize))
672 return 0;
673 } else {
674 if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
675 check_bytes_and_report(s, page, p, "Alignment padding",
676 endobject, POISON_INUSE, s->inuse - s->objsize);
680 if (s->flags & SLAB_POISON) {
681 if (!active && (s->flags & __OBJECT_POISON) &&
682 (!check_bytes_and_report(s, page, p, "Poison", p,
683 POISON_FREE, s->objsize - 1) ||
684 !check_bytes_and_report(s, page, p, "Poison",
685 p + s->objsize - 1, POISON_END, 1)))
686 return 0;
688 * check_pad_bytes cleans up on its own.
690 check_pad_bytes(s, page, p);
693 if (!s->offset && active)
695 * Object and freepointer overlap. Cannot check
696 * freepointer while object is allocated.
698 return 1;
700 /* Check free pointer validity */
701 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
702 object_err(s, page, p, "Freepointer corrupt");
704 * No choice but to zap it and thus lose the remainder
705 * of the free objects in this slab. May cause
706 * another error because the object count is now wrong.
708 set_freepointer(s, p, NULL);
709 return 0;
711 return 1;
714 static int check_slab(struct kmem_cache *s, struct page *page)
716 int maxobj;
718 VM_BUG_ON(!irqs_disabled());
720 if (!PageSlab(page)) {
721 slab_err(s, page, "Not a valid slab page");
722 return 0;
725 maxobj = (PAGE_SIZE << compound_order(page)) / s->size;
726 if (page->objects > maxobj) {
727 slab_err(s, page, "objects %u > max %u",
728 s->name, page->objects, maxobj);
729 return 0;
731 if (page->inuse > page->objects) {
732 slab_err(s, page, "inuse %u > max %u",
733 s->name, page->inuse, page->objects);
734 return 0;
736 /* Slab_pad_check fixes things up after itself */
737 slab_pad_check(s, page);
738 return 1;
742 * Determine if a certain object on a page is on the freelist. Must hold the
743 * slab lock to guarantee that the chains are in a consistent state.
745 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
747 int nr = 0;
748 void *fp = page->freelist;
749 void *object = NULL;
750 unsigned long max_objects;
752 while (fp && nr <= page->objects) {
753 if (fp == search)
754 return 1;
755 if (!check_valid_pointer(s, page, fp)) {
756 if (object) {
757 object_err(s, page, object,
758 "Freechain corrupt");
759 set_freepointer(s, object, NULL);
760 break;
761 } else {
762 slab_err(s, page, "Freepointer corrupt");
763 page->freelist = NULL;
764 page->inuse = page->objects;
765 slab_fix(s, "Freelist cleared");
766 return 0;
768 break;
770 object = fp;
771 fp = get_freepointer(s, object);
772 nr++;
775 max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
776 if (max_objects > MAX_OBJS_PER_PAGE)
777 max_objects = MAX_OBJS_PER_PAGE;
779 if (page->objects != max_objects) {
780 slab_err(s, page, "Wrong number of objects. Found %d but "
781 "should be %d", page->objects, max_objects);
782 page->objects = max_objects;
783 slab_fix(s, "Number of objects adjusted.");
785 if (page->inuse != page->objects - nr) {
786 slab_err(s, page, "Wrong object count. Counter is %d but "
787 "counted were %d", page->inuse, page->objects - nr);
788 page->inuse = page->objects - nr;
789 slab_fix(s, "Object count adjusted.");
791 return search == NULL;
794 static void trace(struct kmem_cache *s, struct page *page, void *object,
795 int alloc)
797 if (s->flags & SLAB_TRACE) {
798 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
799 s->name,
800 alloc ? "alloc" : "free",
801 object, page->inuse,
802 page->freelist);
804 if (!alloc)
805 print_section("Object", (void *)object, s->objsize);
807 dump_stack();
812 * Tracking of fully allocated slabs for debugging purposes.
814 static void add_full(struct kmem_cache_node *n, struct page *page)
816 spin_lock(&n->list_lock);
817 list_add(&page->lru, &n->full);
818 spin_unlock(&n->list_lock);
821 static void remove_full(struct kmem_cache *s, struct page *page)
823 struct kmem_cache_node *n;
825 if (!(s->flags & SLAB_STORE_USER))
826 return;
828 n = get_node(s, page_to_nid(page));
830 spin_lock(&n->list_lock);
831 list_del(&page->lru);
832 spin_unlock(&n->list_lock);
835 /* Tracking of the number of slabs for debugging purposes */
836 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
838 struct kmem_cache_node *n = get_node(s, node);
840 return atomic_long_read(&n->nr_slabs);
843 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
845 return atomic_long_read(&n->nr_slabs);
848 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
850 struct kmem_cache_node *n = get_node(s, node);
853 * May be called early in order to allocate a slab for the
854 * kmem_cache_node structure. Solve the chicken-egg
855 * dilemma by deferring the increment of the count during
856 * bootstrap (see early_kmem_cache_node_alloc).
858 if (!NUMA_BUILD || n) {
859 atomic_long_inc(&n->nr_slabs);
860 atomic_long_add(objects, &n->total_objects);
863 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
865 struct kmem_cache_node *n = get_node(s, node);
867 atomic_long_dec(&n->nr_slabs);
868 atomic_long_sub(objects, &n->total_objects);
871 /* Object debug checks for alloc/free paths */
872 static void setup_object_debug(struct kmem_cache *s, struct page *page,
873 void *object)
875 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
876 return;
878 init_object(s, object, 0);
879 init_tracking(s, object);
882 static int alloc_debug_processing(struct kmem_cache *s, struct page *page,
883 void *object, unsigned long addr)
885 if (!check_slab(s, page))
886 goto bad;
888 if (!on_freelist(s, page, object)) {
889 object_err(s, page, object, "Object already allocated");
890 goto bad;
893 if (!check_valid_pointer(s, page, object)) {
894 object_err(s, page, object, "Freelist Pointer check fails");
895 goto bad;
898 if (!check_object(s, page, object, 0))
899 goto bad;
901 /* Success perform special debug activities for allocs */
902 if (s->flags & SLAB_STORE_USER)
903 set_track(s, object, TRACK_ALLOC, addr);
904 trace(s, page, object, 1);
905 init_object(s, object, 1);
906 return 1;
908 bad:
909 if (PageSlab(page)) {
911 * If this is a slab page then lets do the best we can
912 * to avoid issues in the future. Marking all objects
913 * as used avoids touching the remaining objects.
915 slab_fix(s, "Marking all objects used");
916 page->inuse = page->objects;
917 page->freelist = NULL;
919 return 0;
922 static int free_debug_processing(struct kmem_cache *s, struct page *page,
923 void *object, unsigned long addr)
925 if (!check_slab(s, page))
926 goto fail;
928 if (!check_valid_pointer(s, page, object)) {
929 slab_err(s, page, "Invalid object pointer 0x%p", object);
930 goto fail;
933 if (on_freelist(s, page, object)) {
934 object_err(s, page, object, "Object already free");
935 goto fail;
938 if (!check_object(s, page, object, 1))
939 return 0;
941 if (unlikely(s != page->slab)) {
942 if (!PageSlab(page)) {
943 slab_err(s, page, "Attempt to free object(0x%p) "
944 "outside of slab", object);
945 } else if (!page->slab) {
946 printk(KERN_ERR
947 "SLUB <none>: no slab for object 0x%p.\n",
948 object);
949 dump_stack();
950 } else
951 object_err(s, page, object,
952 "page slab pointer corrupt.");
953 goto fail;
956 /* Special debug activities for freeing objects */
957 if (!PageSlubFrozen(page) && !page->freelist)
958 remove_full(s, page);
959 if (s->flags & SLAB_STORE_USER)
960 set_track(s, object, TRACK_FREE, addr);
961 trace(s, page, object, 0);
962 init_object(s, object, 0);
963 return 1;
965 fail:
966 slab_fix(s, "Object at 0x%p not freed", object);
967 return 0;
970 static int __init setup_slub_debug(char *str)
972 slub_debug = DEBUG_DEFAULT_FLAGS;
973 if (*str++ != '=' || !*str)
975 * No options specified. Switch on full debugging.
977 goto out;
979 if (*str == ',')
981 * No options but restriction on slabs. This means full
982 * debugging for slabs matching a pattern.
984 goto check_slabs;
986 slub_debug = 0;
987 if (*str == '-')
989 * Switch off all debugging measures.
991 goto out;
994 * Determine which debug features should be switched on
996 for (; *str && *str != ','; str++) {
997 switch (tolower(*str)) {
998 case 'f':
999 slub_debug |= SLAB_DEBUG_FREE;
1000 break;
1001 case 'z':
1002 slub_debug |= SLAB_RED_ZONE;
1003 break;
1004 case 'p':
1005 slub_debug |= SLAB_POISON;
1006 break;
1007 case 'u':
1008 slub_debug |= SLAB_STORE_USER;
1009 break;
1010 case 't':
1011 slub_debug |= SLAB_TRACE;
1012 break;
1013 default:
1014 printk(KERN_ERR "slub_debug option '%c' "
1015 "unknown. skipped\n", *str);
1019 check_slabs:
1020 if (*str == ',')
1021 slub_debug_slabs = str + 1;
1022 out:
1023 return 1;
1026 __setup("slub_debug", setup_slub_debug);
1028 static unsigned long kmem_cache_flags(unsigned long objsize,
1029 unsigned long flags, const char *name,
1030 void (*ctor)(void *))
1033 * Enable debugging if selected on the kernel commandline.
1035 if (slub_debug && (!slub_debug_slabs ||
1036 strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)) == 0))
1037 flags |= slub_debug;
1039 return flags;
1041 #else
1042 static inline void setup_object_debug(struct kmem_cache *s,
1043 struct page *page, void *object) {}
1045 static inline int alloc_debug_processing(struct kmem_cache *s,
1046 struct page *page, void *object, unsigned long addr) { return 0; }
1048 static inline int free_debug_processing(struct kmem_cache *s,
1049 struct page *page, void *object, unsigned long addr) { return 0; }
1051 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1052 { return 1; }
1053 static inline int check_object(struct kmem_cache *s, struct page *page,
1054 void *object, int active) { return 1; }
1055 static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
1056 static inline unsigned long kmem_cache_flags(unsigned long objsize,
1057 unsigned long flags, const char *name,
1058 void (*ctor)(void *))
1060 return flags;
1062 #define slub_debug 0
1064 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1065 { return 0; }
1066 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1067 { return 0; }
1068 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1069 int objects) {}
1070 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1071 int objects) {}
1072 #endif
1075 * Slab allocation and freeing
1077 static inline struct page *alloc_slab_page(gfp_t flags, int node,
1078 struct kmem_cache_order_objects oo)
1080 int order = oo_order(oo);
1082 flags |= __GFP_NOTRACK;
1084 if (node == -1)
1085 return alloc_pages(flags, order);
1086 else
1087 return alloc_pages_node(node, flags, order);
1090 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1092 struct page *page;
1093 struct kmem_cache_order_objects oo = s->oo;
1095 flags |= s->allocflags;
1097 page = alloc_slab_page(flags | __GFP_NOWARN | __GFP_NORETRY, node,
1098 oo);
1099 if (unlikely(!page)) {
1100 oo = s->min;
1102 * Allocation may have failed due to fragmentation.
1103 * Try a lower order alloc if possible
1105 page = alloc_slab_page(flags, node, oo);
1106 if (!page)
1107 return NULL;
1109 stat(get_cpu_slab(s, raw_smp_processor_id()), ORDER_FALLBACK);
1112 if (kmemcheck_enabled
1113 && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS)))
1115 int pages = 1 << oo_order(oo);
1117 kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1120 * Objects from caches that have a constructor don't get
1121 * cleared when they're allocated, so we need to do it here.
1123 if (s->ctor)
1124 kmemcheck_mark_uninitialized_pages(page, pages);
1125 else
1126 kmemcheck_mark_unallocated_pages(page, pages);
1129 page->objects = oo_objects(oo);
1130 mod_zone_page_state(page_zone(page),
1131 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1132 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1133 1 << oo_order(oo));
1135 return page;
1138 static void setup_object(struct kmem_cache *s, struct page *page,
1139 void *object)
1141 setup_object_debug(s, page, object);
1142 if (unlikely(s->ctor))
1143 s->ctor(object);
1146 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1148 struct page *page;
1149 void *start;
1150 void *last;
1151 void *p;
1153 BUG_ON(flags & GFP_SLAB_BUG_MASK);
1155 page = allocate_slab(s,
1156 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1157 if (!page)
1158 goto out;
1160 inc_slabs_node(s, page_to_nid(page), page->objects);
1161 page->slab = s;
1162 page->flags |= 1 << PG_slab;
1163 if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
1164 SLAB_STORE_USER | SLAB_TRACE))
1165 __SetPageSlubDebug(page);
1167 start = page_address(page);
1169 if (unlikely(s->flags & SLAB_POISON))
1170 memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
1172 last = start;
1173 for_each_object(p, s, start, page->objects) {
1174 setup_object(s, page, last);
1175 set_freepointer(s, last, p);
1176 last = p;
1178 setup_object(s, page, last);
1179 set_freepointer(s, last, NULL);
1181 page->freelist = start;
1182 page->inuse = 0;
1183 out:
1184 return page;
1187 static void __free_slab(struct kmem_cache *s, struct page *page)
1189 int order = compound_order(page);
1190 int pages = 1 << order;
1192 if (unlikely(SLABDEBUG && PageSlubDebug(page))) {
1193 void *p;
1195 slab_pad_check(s, page);
1196 for_each_object(p, s, page_address(page),
1197 page->objects)
1198 check_object(s, page, p, 0);
1199 __ClearPageSlubDebug(page);
1202 kmemcheck_free_shadow(page, compound_order(page));
1204 mod_zone_page_state(page_zone(page),
1205 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1206 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1207 -pages);
1209 __ClearPageSlab(page);
1210 reset_page_mapcount(page);
1211 if (current->reclaim_state)
1212 current->reclaim_state->reclaimed_slab += pages;
1213 __free_pages(page, order);
1216 static void rcu_free_slab(struct rcu_head *h)
1218 struct page *page;
1220 page = container_of((struct list_head *)h, struct page, lru);
1221 __free_slab(page->slab, page);
1224 static void free_slab(struct kmem_cache *s, struct page *page)
1226 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1228 * RCU free overloads the RCU head over the LRU
1230 struct rcu_head *head = (void *)&page->lru;
1232 call_rcu(head, rcu_free_slab);
1233 } else
1234 __free_slab(s, page);
1237 static void discard_slab(struct kmem_cache *s, struct page *page)
1239 dec_slabs_node(s, page_to_nid(page), page->objects);
1240 free_slab(s, page);
1244 * Per slab locking using the pagelock
1246 static __always_inline void slab_lock(struct page *page)
1248 bit_spin_lock(PG_locked, &page->flags);
1251 static __always_inline void slab_unlock(struct page *page)
1253 __bit_spin_unlock(PG_locked, &page->flags);
1256 static __always_inline int slab_trylock(struct page *page)
1258 int rc = 1;
1260 rc = bit_spin_trylock(PG_locked, &page->flags);
1261 return rc;
1265 * Management of partially allocated slabs
1267 static void add_partial(struct kmem_cache_node *n,
1268 struct page *page, int tail)
1270 spin_lock(&n->list_lock);
1271 n->nr_partial++;
1272 if (tail)
1273 list_add_tail(&page->lru, &n->partial);
1274 else
1275 list_add(&page->lru, &n->partial);
1276 spin_unlock(&n->list_lock);
1279 static void remove_partial(struct kmem_cache *s, struct page *page)
1281 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1283 spin_lock(&n->list_lock);
1284 list_del(&page->lru);
1285 n->nr_partial--;
1286 spin_unlock(&n->list_lock);
1290 * Lock slab and remove from the partial list.
1292 * Must hold list_lock.
1294 static inline int lock_and_freeze_slab(struct kmem_cache_node *n,
1295 struct page *page)
1297 if (slab_trylock(page)) {
1298 list_del(&page->lru);
1299 n->nr_partial--;
1300 __SetPageSlubFrozen(page);
1301 return 1;
1303 return 0;
1307 * Try to allocate a partial slab from a specific node.
1309 static struct page *get_partial_node(struct kmem_cache_node *n)
1311 struct page *page;
1314 * Racy check. If we mistakenly see no partial slabs then we
1315 * just allocate an empty slab. If we mistakenly try to get a
1316 * partial slab and there is none available then get_partials()
1317 * will return NULL.
1319 if (!n || !n->nr_partial)
1320 return NULL;
1322 spin_lock(&n->list_lock);
1323 list_for_each_entry(page, &n->partial, lru)
1324 if (lock_and_freeze_slab(n, page))
1325 goto out;
1326 page = NULL;
1327 out:
1328 spin_unlock(&n->list_lock);
1329 return page;
1333 * Get a page from somewhere. Search in increasing NUMA distances.
1335 static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
1337 #ifdef CONFIG_NUMA
1338 struct zonelist *zonelist;
1339 struct zoneref *z;
1340 struct zone *zone;
1341 enum zone_type high_zoneidx = gfp_zone(flags);
1342 struct page *page;
1345 * The defrag ratio allows a configuration of the tradeoffs between
1346 * inter node defragmentation and node local allocations. A lower
1347 * defrag_ratio increases the tendency to do local allocations
1348 * instead of attempting to obtain partial slabs from other nodes.
1350 * If the defrag_ratio is set to 0 then kmalloc() always
1351 * returns node local objects. If the ratio is higher then kmalloc()
1352 * may return off node objects because partial slabs are obtained
1353 * from other nodes and filled up.
1355 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1356 * defrag_ratio = 1000) then every (well almost) allocation will
1357 * first attempt to defrag slab caches on other nodes. This means
1358 * scanning over all nodes to look for partial slabs which may be
1359 * expensive if we do it every time we are trying to find a slab
1360 * with available objects.
1362 if (!s->remote_node_defrag_ratio ||
1363 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1364 return NULL;
1366 zonelist = node_zonelist(slab_node(current->mempolicy), flags);
1367 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1368 struct kmem_cache_node *n;
1370 n = get_node(s, zone_to_nid(zone));
1372 if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1373 n->nr_partial > s->min_partial) {
1374 page = get_partial_node(n);
1375 if (page)
1376 return page;
1379 #endif
1380 return NULL;
1384 * Get a partial page, lock it and return it.
1386 static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
1388 struct page *page;
1389 int searchnode = (node == -1) ? numa_node_id() : node;
1391 page = get_partial_node(get_node(s, searchnode));
1392 if (page || (flags & __GFP_THISNODE))
1393 return page;
1395 return get_any_partial(s, flags);
1399 * Move a page back to the lists.
1401 * Must be called with the slab lock held.
1403 * On exit the slab lock will have been dropped.
1405 static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
1407 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1408 struct kmem_cache_cpu *c = get_cpu_slab(s, smp_processor_id());
1410 __ClearPageSlubFrozen(page);
1411 if (page->inuse) {
1413 if (page->freelist) {
1414 add_partial(n, page, tail);
1415 stat(c, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
1416 } else {
1417 stat(c, DEACTIVATE_FULL);
1418 if (SLABDEBUG && PageSlubDebug(page) &&
1419 (s->flags & SLAB_STORE_USER))
1420 add_full(n, page);
1422 slab_unlock(page);
1423 } else {
1424 stat(c, DEACTIVATE_EMPTY);
1425 if (n->nr_partial < s->min_partial) {
1427 * Adding an empty slab to the partial slabs in order
1428 * to avoid page allocator overhead. This slab needs
1429 * to come after the other slabs with objects in
1430 * so that the others get filled first. That way the
1431 * size of the partial list stays small.
1433 * kmem_cache_shrink can reclaim any empty slabs from
1434 * the partial list.
1436 add_partial(n, page, 1);
1437 slab_unlock(page);
1438 } else {
1439 slab_unlock(page);
1440 stat(get_cpu_slab(s, raw_smp_processor_id()), FREE_SLAB);
1441 discard_slab(s, page);
1447 * Remove the cpu slab
1449 static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1451 struct page *page = c->page;
1452 int tail = 1;
1454 if (page->freelist)
1455 stat(c, DEACTIVATE_REMOTE_FREES);
1457 * Merge cpu freelist into slab freelist. Typically we get here
1458 * because both freelists are empty. So this is unlikely
1459 * to occur.
1461 while (unlikely(c->freelist)) {
1462 void **object;
1464 tail = 0; /* Hot objects. Put the slab first */
1466 /* Retrieve object from cpu_freelist */
1467 object = c->freelist;
1468 c->freelist = c->freelist[c->offset];
1470 /* And put onto the regular freelist */
1471 object[c->offset] = page->freelist;
1472 page->freelist = object;
1473 page->inuse--;
1475 c->page = NULL;
1476 unfreeze_slab(s, page, tail);
1479 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1481 stat(c, CPUSLAB_FLUSH);
1482 slab_lock(c->page);
1483 deactivate_slab(s, c);
1487 * Flush cpu slab.
1489 * Called from IPI handler with interrupts disabled.
1491 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
1493 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
1495 if (likely(c && c->page))
1496 flush_slab(s, c);
1499 static void flush_cpu_slab(void *d)
1501 struct kmem_cache *s = d;
1503 __flush_cpu_slab(s, smp_processor_id());
1506 static void flush_all(struct kmem_cache *s)
1508 on_each_cpu(flush_cpu_slab, s, 1);
1512 * Check if the objects in a per cpu structure fit numa
1513 * locality expectations.
1515 static inline int node_match(struct kmem_cache_cpu *c, int node)
1517 #ifdef CONFIG_NUMA
1518 if (node != -1 && c->node != node)
1519 return 0;
1520 #endif
1521 return 1;
1524 static int count_free(struct page *page)
1526 return page->objects - page->inuse;
1529 static unsigned long count_partial(struct kmem_cache_node *n,
1530 int (*get_count)(struct page *))
1532 unsigned long flags;
1533 unsigned long x = 0;
1534 struct page *page;
1536 spin_lock_irqsave(&n->list_lock, flags);
1537 list_for_each_entry(page, &n->partial, lru)
1538 x += get_count(page);
1539 spin_unlock_irqrestore(&n->list_lock, flags);
1540 return x;
1543 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
1545 #ifdef CONFIG_SLUB_DEBUG
1546 return atomic_long_read(&n->total_objects);
1547 #else
1548 return 0;
1549 #endif
1552 static noinline void
1553 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
1555 int node;
1557 printk(KERN_WARNING
1558 "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1559 nid, gfpflags);
1560 printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
1561 "default order: %d, min order: %d\n", s->name, s->objsize,
1562 s->size, oo_order(s->oo), oo_order(s->min));
1564 for_each_online_node(node) {
1565 struct kmem_cache_node *n = get_node(s, node);
1566 unsigned long nr_slabs;
1567 unsigned long nr_objs;
1568 unsigned long nr_free;
1570 if (!n)
1571 continue;
1573 nr_free = count_partial(n, count_free);
1574 nr_slabs = node_nr_slabs(n);
1575 nr_objs = node_nr_objs(n);
1577 printk(KERN_WARNING
1578 " node %d: slabs: %ld, objs: %ld, free: %ld\n",
1579 node, nr_slabs, nr_objs, nr_free);
1584 * Slow path. The lockless freelist is empty or we need to perform
1585 * debugging duties.
1587 * Interrupts are disabled.
1589 * Processing is still very fast if new objects have been freed to the
1590 * regular freelist. In that case we simply take over the regular freelist
1591 * as the lockless freelist and zap the regular freelist.
1593 * If that is not working then we fall back to the partial lists. We take the
1594 * first element of the freelist as the object to allocate now and move the
1595 * rest of the freelist to the lockless freelist.
1597 * And if we were unable to get a new slab from the partial slab lists then
1598 * we need to allocate a new slab. This is the slowest path since it involves
1599 * a call to the page allocator and the setup of a new slab.
1601 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
1602 unsigned long addr, struct kmem_cache_cpu *c)
1604 void **object;
1605 struct page *new;
1607 /* We handle __GFP_ZERO in the caller */
1608 gfpflags &= ~__GFP_ZERO;
1610 if (!c->page)
1611 goto new_slab;
1613 slab_lock(c->page);
1614 if (unlikely(!node_match(c, node)))
1615 goto another_slab;
1617 stat(c, ALLOC_REFILL);
1619 load_freelist:
1620 object = c->page->freelist;
1621 if (unlikely(!object))
1622 goto another_slab;
1623 if (unlikely(SLABDEBUG && PageSlubDebug(c->page)))
1624 goto debug;
1626 c->freelist = object[c->offset];
1627 c->page->inuse = c->page->objects;
1628 c->page->freelist = NULL;
1629 c->node = page_to_nid(c->page);
1630 unlock_out:
1631 slab_unlock(c->page);
1632 stat(c, ALLOC_SLOWPATH);
1633 return object;
1635 another_slab:
1636 deactivate_slab(s, c);
1638 new_slab:
1639 new = get_partial(s, gfpflags, node);
1640 if (new) {
1641 c->page = new;
1642 stat(c, ALLOC_FROM_PARTIAL);
1643 goto load_freelist;
1646 if (gfpflags & __GFP_WAIT)
1647 local_irq_enable();
1649 new = new_slab(s, gfpflags, node);
1651 if (gfpflags & __GFP_WAIT)
1652 local_irq_disable();
1654 if (new) {
1655 c = get_cpu_slab(s, smp_processor_id());
1656 stat(c, ALLOC_SLAB);
1657 if (c->page)
1658 flush_slab(s, c);
1659 slab_lock(new);
1660 __SetPageSlubFrozen(new);
1661 c->page = new;
1662 goto load_freelist;
1664 if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
1665 slab_out_of_memory(s, gfpflags, node);
1666 return NULL;
1667 debug:
1668 if (!alloc_debug_processing(s, c->page, object, addr))
1669 goto another_slab;
1671 c->page->inuse++;
1672 c->page->freelist = object[c->offset];
1673 c->node = -1;
1674 goto unlock_out;
1678 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1679 * have the fastpath folded into their functions. So no function call
1680 * overhead for requests that can be satisfied on the fastpath.
1682 * The fastpath works by first checking if the lockless freelist can be used.
1683 * If not then __slab_alloc is called for slow processing.
1685 * Otherwise we can simply pick the next object from the lockless free list.
1687 static __always_inline void *slab_alloc(struct kmem_cache *s,
1688 gfp_t gfpflags, int node, unsigned long addr)
1690 void **object;
1691 struct kmem_cache_cpu *c;
1692 unsigned long flags;
1693 unsigned int objsize;
1695 gfpflags &= slab_gfp_mask;
1697 lockdep_trace_alloc(gfpflags);
1698 might_sleep_if(gfpflags & __GFP_WAIT);
1700 if (should_failslab(s->objsize, gfpflags))
1701 return NULL;
1703 local_irq_save(flags);
1704 c = get_cpu_slab(s, smp_processor_id());
1705 objsize = c->objsize;
1706 if (unlikely(!c->freelist || !node_match(c, node)))
1708 object = __slab_alloc(s, gfpflags, node, addr, c);
1710 else {
1711 object = c->freelist;
1712 c->freelist = object[c->offset];
1713 stat(c, ALLOC_FASTPATH);
1715 local_irq_restore(flags);
1717 if (unlikely((gfpflags & __GFP_ZERO) && object))
1718 memset(object, 0, objsize);
1720 kmemcheck_slab_alloc(s, gfpflags, object, c->objsize);
1721 kmemleak_alloc_recursive(object, objsize, 1, s->flags, gfpflags);
1723 return object;
1726 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
1728 void *ret = slab_alloc(s, gfpflags, -1, _RET_IP_);
1730 trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
1732 return ret;
1734 EXPORT_SYMBOL(kmem_cache_alloc);
1736 #ifdef CONFIG_KMEMTRACE
1737 void *kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags)
1739 return slab_alloc(s, gfpflags, -1, _RET_IP_);
1741 EXPORT_SYMBOL(kmem_cache_alloc_notrace);
1742 #endif
1744 #ifdef CONFIG_NUMA
1745 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
1747 void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
1749 trace_kmem_cache_alloc_node(_RET_IP_, ret,
1750 s->objsize, s->size, gfpflags, node);
1752 return ret;
1754 EXPORT_SYMBOL(kmem_cache_alloc_node);
1755 #endif
1757 #ifdef CONFIG_KMEMTRACE
1758 void *kmem_cache_alloc_node_notrace(struct kmem_cache *s,
1759 gfp_t gfpflags,
1760 int node)
1762 return slab_alloc(s, gfpflags, node, _RET_IP_);
1764 EXPORT_SYMBOL(kmem_cache_alloc_node_notrace);
1765 #endif
1768 * Slow patch handling. This may still be called frequently since objects
1769 * have a longer lifetime than the cpu slabs in most processing loads.
1771 * So we still attempt to reduce cache line usage. Just take the slab
1772 * lock and free the item. If there is no additional partial page
1773 * handling required then we can return immediately.
1775 static void __slab_free(struct kmem_cache *s, struct page *page,
1776 void *x, unsigned long addr, unsigned int offset)
1778 void *prior;
1779 void **object = (void *)x;
1780 struct kmem_cache_cpu *c;
1782 c = get_cpu_slab(s, raw_smp_processor_id());
1783 stat(c, FREE_SLOWPATH);
1784 slab_lock(page);
1786 if (unlikely(SLABDEBUG && PageSlubDebug(page)))
1787 goto debug;
1789 checks_ok:
1790 prior = object[offset] = page->freelist;
1791 page->freelist = object;
1792 page->inuse--;
1794 if (unlikely(PageSlubFrozen(page))) {
1795 stat(c, FREE_FROZEN);
1796 goto out_unlock;
1799 if (unlikely(!page->inuse))
1800 goto slab_empty;
1803 * Objects left in the slab. If it was not on the partial list before
1804 * then add it.
1806 if (unlikely(!prior)) {
1807 add_partial(get_node(s, page_to_nid(page)), page, 1);
1808 stat(c, FREE_ADD_PARTIAL);
1811 out_unlock:
1812 slab_unlock(page);
1813 return;
1815 slab_empty:
1816 if (prior) {
1818 * Slab still on the partial list.
1820 remove_partial(s, page);
1821 stat(c, FREE_REMOVE_PARTIAL);
1823 slab_unlock(page);
1824 stat(c, FREE_SLAB);
1825 discard_slab(s, page);
1826 return;
1828 debug:
1829 if (!free_debug_processing(s, page, x, addr))
1830 goto out_unlock;
1831 goto checks_ok;
1835 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1836 * can perform fastpath freeing without additional function calls.
1838 * The fastpath is only possible if we are freeing to the current cpu slab
1839 * of this processor. This typically the case if we have just allocated
1840 * the item before.
1842 * If fastpath is not possible then fall back to __slab_free where we deal
1843 * with all sorts of special processing.
1845 static __always_inline void slab_free(struct kmem_cache *s,
1846 struct page *page, void *x, unsigned long addr)
1848 void **object = (void *)x;
1849 struct kmem_cache_cpu *c;
1850 unsigned long flags;
1852 kmemleak_free_recursive(x, s->flags);
1853 local_irq_save(flags);
1854 c = get_cpu_slab(s, smp_processor_id());
1855 kmemcheck_slab_free(s, object, c->objsize);
1856 debug_check_no_locks_freed(object, c->objsize);
1857 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1858 debug_check_no_obj_freed(object, c->objsize);
1859 if (likely(page == c->page && c->node >= 0)) {
1860 object[c->offset] = c->freelist;
1861 c->freelist = object;
1862 stat(c, FREE_FASTPATH);
1863 } else
1864 __slab_free(s, page, x, addr, c->offset);
1866 local_irq_restore(flags);
1869 void kmem_cache_free(struct kmem_cache *s, void *x)
1871 struct page *page;
1873 page = virt_to_head_page(x);
1875 slab_free(s, page, x, _RET_IP_);
1877 trace_kmem_cache_free(_RET_IP_, x);
1879 EXPORT_SYMBOL(kmem_cache_free);
1881 /* Figure out on which slab page the object resides */
1882 static struct page *get_object_page(const void *x)
1884 struct page *page = virt_to_head_page(x);
1886 if (!PageSlab(page))
1887 return NULL;
1889 return page;
1893 * Object placement in a slab is made very easy because we always start at
1894 * offset 0. If we tune the size of the object to the alignment then we can
1895 * get the required alignment by putting one properly sized object after
1896 * another.
1898 * Notice that the allocation order determines the sizes of the per cpu
1899 * caches. Each processor has always one slab available for allocations.
1900 * Increasing the allocation order reduces the number of times that slabs
1901 * must be moved on and off the partial lists and is therefore a factor in
1902 * locking overhead.
1906 * Mininum / Maximum order of slab pages. This influences locking overhead
1907 * and slab fragmentation. A higher order reduces the number of partial slabs
1908 * and increases the number of allocations possible without having to
1909 * take the list_lock.
1911 static int slub_min_order;
1912 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
1913 static int slub_min_objects;
1916 * Merge control. If this is set then no merging of slab caches will occur.
1917 * (Could be removed. This was introduced to pacify the merge skeptics.)
1919 static int slub_nomerge;
1922 * Calculate the order of allocation given an slab object size.
1924 * The order of allocation has significant impact on performance and other
1925 * system components. Generally order 0 allocations should be preferred since
1926 * order 0 does not cause fragmentation in the page allocator. Larger objects
1927 * be problematic to put into order 0 slabs because there may be too much
1928 * unused space left. We go to a higher order if more than 1/16th of the slab
1929 * would be wasted.
1931 * In order to reach satisfactory performance we must ensure that a minimum
1932 * number of objects is in one slab. Otherwise we may generate too much
1933 * activity on the partial lists which requires taking the list_lock. This is
1934 * less a concern for large slabs though which are rarely used.
1936 * slub_max_order specifies the order where we begin to stop considering the
1937 * number of objects in a slab as critical. If we reach slub_max_order then
1938 * we try to keep the page order as low as possible. So we accept more waste
1939 * of space in favor of a small page order.
1941 * Higher order allocations also allow the placement of more objects in a
1942 * slab and thereby reduce object handling overhead. If the user has
1943 * requested a higher mininum order then we start with that one instead of
1944 * the smallest order which will fit the object.
1946 static inline int slab_order(int size, int min_objects,
1947 int max_order, int fract_leftover)
1949 int order;
1950 int rem;
1951 int min_order = slub_min_order;
1953 if ((PAGE_SIZE << min_order) / size > MAX_OBJS_PER_PAGE)
1954 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
1956 for (order = max(min_order,
1957 fls(min_objects * size - 1) - PAGE_SHIFT);
1958 order <= max_order; order++) {
1960 unsigned long slab_size = PAGE_SIZE << order;
1962 if (slab_size < min_objects * size)
1963 continue;
1965 rem = slab_size % size;
1967 if (rem <= slab_size / fract_leftover)
1968 break;
1972 return order;
1975 static inline int calculate_order(int size)
1977 int order;
1978 int min_objects;
1979 int fraction;
1980 int max_objects;
1983 * Attempt to find best configuration for a slab. This
1984 * works by first attempting to generate a layout with
1985 * the best configuration and backing off gradually.
1987 * First we reduce the acceptable waste in a slab. Then
1988 * we reduce the minimum objects required in a slab.
1990 min_objects = slub_min_objects;
1991 if (!min_objects)
1992 min_objects = 4 * (fls(nr_cpu_ids) + 1);
1993 max_objects = (PAGE_SIZE << slub_max_order)/size;
1994 min_objects = min(min_objects, max_objects);
1996 while (min_objects > 1) {
1997 fraction = 16;
1998 while (fraction >= 4) {
1999 order = slab_order(size, min_objects,
2000 slub_max_order, fraction);
2001 if (order <= slub_max_order)
2002 return order;
2003 fraction /= 2;
2005 min_objects --;
2009 * We were unable to place multiple objects in a slab. Now
2010 * lets see if we can place a single object there.
2012 order = slab_order(size, 1, slub_max_order, 1);
2013 if (order <= slub_max_order)
2014 return order;
2017 * Doh this slab cannot be placed using slub_max_order.
2019 order = slab_order(size, 1, MAX_ORDER, 1);
2020 if (order < MAX_ORDER)
2021 return order;
2022 return -ENOSYS;
2026 * Figure out what the alignment of the objects will be.
2028 static unsigned long calculate_alignment(unsigned long flags,
2029 unsigned long align, unsigned long size)
2032 * If the user wants hardware cache aligned objects then follow that
2033 * suggestion if the object is sufficiently large.
2035 * The hardware cache alignment cannot override the specified
2036 * alignment though. If that is greater then use it.
2038 if (flags & SLAB_HWCACHE_ALIGN) {
2039 unsigned long ralign = cache_line_size();
2040 while (size <= ralign / 2)
2041 ralign /= 2;
2042 align = max(align, ralign);
2045 if (align < ARCH_SLAB_MINALIGN)
2046 align = ARCH_SLAB_MINALIGN;
2048 return ALIGN(align, sizeof(void *));
2051 static void init_kmem_cache_cpu(struct kmem_cache *s,
2052 struct kmem_cache_cpu *c)
2054 c->page = NULL;
2055 c->freelist = NULL;
2056 c->node = 0;
2057 c->offset = s->offset / sizeof(void *);
2058 c->objsize = s->objsize;
2059 #ifdef CONFIG_SLUB_STATS
2060 memset(c->stat, 0, NR_SLUB_STAT_ITEMS * sizeof(unsigned));
2061 #endif
2064 static void
2065 init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
2067 n->nr_partial = 0;
2068 spin_lock_init(&n->list_lock);
2069 INIT_LIST_HEAD(&n->partial);
2070 #ifdef CONFIG_SLUB_DEBUG
2071 atomic_long_set(&n->nr_slabs, 0);
2072 atomic_long_set(&n->total_objects, 0);
2073 INIT_LIST_HEAD(&n->full);
2074 #endif
2077 #ifdef CONFIG_SMP
2079 * Per cpu array for per cpu structures.
2081 * The per cpu array places all kmem_cache_cpu structures from one processor
2082 * close together meaning that it becomes possible that multiple per cpu
2083 * structures are contained in one cacheline. This may be particularly
2084 * beneficial for the kmalloc caches.
2086 * A desktop system typically has around 60-80 slabs. With 100 here we are
2087 * likely able to get per cpu structures for all caches from the array defined
2088 * here. We must be able to cover all kmalloc caches during bootstrap.
2090 * If the per cpu array is exhausted then fall back to kmalloc
2091 * of individual cachelines. No sharing is possible then.
2093 #define NR_KMEM_CACHE_CPU 100
2095 static DEFINE_PER_CPU(struct kmem_cache_cpu,
2096 kmem_cache_cpu)[NR_KMEM_CACHE_CPU];
2098 static DEFINE_PER_CPU(struct kmem_cache_cpu *, kmem_cache_cpu_free);
2099 static DECLARE_BITMAP(kmem_cach_cpu_free_init_once, CONFIG_NR_CPUS);
2101 static struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s,
2102 int cpu, gfp_t flags)
2104 struct kmem_cache_cpu *c = per_cpu(kmem_cache_cpu_free, cpu);
2106 if (c)
2107 per_cpu(kmem_cache_cpu_free, cpu) =
2108 (void *)c->freelist;
2109 else {
2110 /* Table overflow: So allocate ourselves */
2111 c = kmalloc_node(
2112 ALIGN(sizeof(struct kmem_cache_cpu), cache_line_size()),
2113 flags, cpu_to_node(cpu));
2114 if (!c)
2115 return NULL;
2118 init_kmem_cache_cpu(s, c);
2119 return c;
2122 static void free_kmem_cache_cpu(struct kmem_cache_cpu *c, int cpu)
2124 if (c < per_cpu(kmem_cache_cpu, cpu) ||
2125 c >= per_cpu(kmem_cache_cpu, cpu) + NR_KMEM_CACHE_CPU) {
2126 kfree(c);
2127 return;
2129 c->freelist = (void *)per_cpu(kmem_cache_cpu_free, cpu);
2130 per_cpu(kmem_cache_cpu_free, cpu) = c;
2133 static void free_kmem_cache_cpus(struct kmem_cache *s)
2135 int cpu;
2137 for_each_online_cpu(cpu) {
2138 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
2140 if (c) {
2141 s->cpu_slab[cpu] = NULL;
2142 free_kmem_cache_cpu(c, cpu);
2147 static int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
2149 int cpu;
2151 for_each_online_cpu(cpu) {
2152 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
2154 if (c)
2155 continue;
2157 c = alloc_kmem_cache_cpu(s, cpu, flags);
2158 if (!c) {
2159 free_kmem_cache_cpus(s);
2160 return 0;
2162 s->cpu_slab[cpu] = c;
2164 return 1;
2168 * Initialize the per cpu array.
2170 static void init_alloc_cpu_cpu(int cpu)
2172 int i;
2174 if (cpumask_test_cpu(cpu, to_cpumask(kmem_cach_cpu_free_init_once)))
2175 return;
2177 for (i = NR_KMEM_CACHE_CPU - 1; i >= 0; i--)
2178 free_kmem_cache_cpu(&per_cpu(kmem_cache_cpu, cpu)[i], cpu);
2180 cpumask_set_cpu(cpu, to_cpumask(kmem_cach_cpu_free_init_once));
2183 static void __init init_alloc_cpu(void)
2185 int cpu;
2187 for_each_online_cpu(cpu)
2188 init_alloc_cpu_cpu(cpu);
2191 #else
2192 static inline void free_kmem_cache_cpus(struct kmem_cache *s) {}
2193 static inline void init_alloc_cpu(void) {}
2195 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
2197 init_kmem_cache_cpu(s, &s->cpu_slab);
2198 return 1;
2200 #endif
2202 #ifdef CONFIG_NUMA
2204 * No kmalloc_node yet so do it by hand. We know that this is the first
2205 * slab on the node for this slabcache. There are no concurrent accesses
2206 * possible.
2208 * Note that this function only works on the kmalloc_node_cache
2209 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2210 * memory on a fresh node that has no slab structures yet.
2212 static void early_kmem_cache_node_alloc(gfp_t gfpflags, int node)
2214 struct page *page;
2215 struct kmem_cache_node *n;
2216 unsigned long flags;
2218 BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
2220 page = new_slab(kmalloc_caches, gfpflags, node);
2222 BUG_ON(!page);
2223 if (page_to_nid(page) != node) {
2224 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2225 "node %d\n", node);
2226 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2227 "in order to be able to continue\n");
2230 n = page->freelist;
2231 BUG_ON(!n);
2232 page->freelist = get_freepointer(kmalloc_caches, n);
2233 page->inuse++;
2234 kmalloc_caches->node[node] = n;
2235 #ifdef CONFIG_SLUB_DEBUG
2236 init_object(kmalloc_caches, n, 1);
2237 init_tracking(kmalloc_caches, n);
2238 #endif
2239 init_kmem_cache_node(n, kmalloc_caches);
2240 inc_slabs_node(kmalloc_caches, node, page->objects);
2243 * lockdep requires consistent irq usage for each lock
2244 * so even though there cannot be a race this early in
2245 * the boot sequence, we still disable irqs.
2247 local_irq_save(flags);
2248 add_partial(n, page, 0);
2249 local_irq_restore(flags);
2252 static void free_kmem_cache_nodes(struct kmem_cache *s)
2254 int node;
2256 for_each_node_state(node, N_NORMAL_MEMORY) {
2257 struct kmem_cache_node *n = s->node[node];
2258 if (n && n != &s->local_node)
2259 kmem_cache_free(kmalloc_caches, n);
2260 s->node[node] = NULL;
2264 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2266 int node;
2267 int local_node;
2269 if (slab_state >= UP)
2270 local_node = page_to_nid(virt_to_page(s));
2271 else
2272 local_node = 0;
2274 for_each_node_state(node, N_NORMAL_MEMORY) {
2275 struct kmem_cache_node *n;
2277 if (local_node == node)
2278 n = &s->local_node;
2279 else {
2280 if (slab_state == DOWN) {
2281 early_kmem_cache_node_alloc(gfpflags, node);
2282 continue;
2284 n = kmem_cache_alloc_node(kmalloc_caches,
2285 gfpflags, node);
2287 if (!n) {
2288 free_kmem_cache_nodes(s);
2289 return 0;
2293 s->node[node] = n;
2294 init_kmem_cache_node(n, s);
2296 return 1;
2298 #else
2299 static void free_kmem_cache_nodes(struct kmem_cache *s)
2303 static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
2305 init_kmem_cache_node(&s->local_node, s);
2306 return 1;
2308 #endif
2310 static void set_min_partial(struct kmem_cache *s, unsigned long min)
2312 if (min < MIN_PARTIAL)
2313 min = MIN_PARTIAL;
2314 else if (min > MAX_PARTIAL)
2315 min = MAX_PARTIAL;
2316 s->min_partial = min;
2320 * calculate_sizes() determines the order and the distribution of data within
2321 * a slab object.
2323 static int calculate_sizes(struct kmem_cache *s, int forced_order)
2325 unsigned long flags = s->flags;
2326 unsigned long size = s->objsize;
2327 unsigned long align = s->align;
2328 int order;
2331 * Round up object size to the next word boundary. We can only
2332 * place the free pointer at word boundaries and this determines
2333 * the possible location of the free pointer.
2335 size = ALIGN(size, sizeof(void *));
2337 #ifdef CONFIG_SLUB_DEBUG
2339 * Determine if we can poison the object itself. If the user of
2340 * the slab may touch the object after free or before allocation
2341 * then we should never poison the object itself.
2343 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2344 !s->ctor)
2345 s->flags |= __OBJECT_POISON;
2346 else
2347 s->flags &= ~__OBJECT_POISON;
2351 * If we are Redzoning then check if there is some space between the
2352 * end of the object and the free pointer. If not then add an
2353 * additional word to have some bytes to store Redzone information.
2355 if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2356 size += sizeof(void *);
2357 #endif
2360 * With that we have determined the number of bytes in actual use
2361 * by the object. This is the potential offset to the free pointer.
2363 s->inuse = size;
2365 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2366 s->ctor)) {
2368 * Relocate free pointer after the object if it is not
2369 * permitted to overwrite the first word of the object on
2370 * kmem_cache_free.
2372 * This is the case if we do RCU, have a constructor or
2373 * destructor or are poisoning the objects.
2375 s->offset = size;
2376 size += sizeof(void *);
2379 #ifdef CONFIG_SLUB_DEBUG
2380 if (flags & SLAB_STORE_USER)
2382 * Need to store information about allocs and frees after
2383 * the object.
2385 size += 2 * sizeof(struct track);
2387 if (flags & SLAB_RED_ZONE)
2389 * Add some empty padding so that we can catch
2390 * overwrites from earlier objects rather than let
2391 * tracking information or the free pointer be
2392 * corrupted if a user writes before the start
2393 * of the object.
2395 size += sizeof(void *);
2396 #endif
2399 * Determine the alignment based on various parameters that the
2400 * user specified and the dynamic determination of cache line size
2401 * on bootup.
2403 align = calculate_alignment(flags, align, s->objsize);
2406 * SLUB stores one object immediately after another beginning from
2407 * offset 0. In order to align the objects we have to simply size
2408 * each object to conform to the alignment.
2410 size = ALIGN(size, align);
2411 s->size = size;
2412 if (forced_order >= 0)
2413 order = forced_order;
2414 else
2415 order = calculate_order(size);
2417 if (order < 0)
2418 return 0;
2420 s->allocflags = 0;
2421 if (order)
2422 s->allocflags |= __GFP_COMP;
2424 if (s->flags & SLAB_CACHE_DMA)
2425 s->allocflags |= SLUB_DMA;
2427 if (s->flags & SLAB_RECLAIM_ACCOUNT)
2428 s->allocflags |= __GFP_RECLAIMABLE;
2431 * Determine the number of objects per slab
2433 s->oo = oo_make(order, size);
2434 s->min = oo_make(get_order(size), size);
2435 if (oo_objects(s->oo) > oo_objects(s->max))
2436 s->max = s->oo;
2438 return !!oo_objects(s->oo);
2442 static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
2443 const char *name, size_t size,
2444 size_t align, unsigned long flags,
2445 void (*ctor)(void *))
2447 memset(s, 0, kmem_size);
2448 s->name = name;
2449 s->ctor = ctor;
2450 s->objsize = size;
2451 s->align = align;
2452 s->flags = kmem_cache_flags(size, flags, name, ctor);
2454 if (!calculate_sizes(s, -1))
2455 goto error;
2458 * The larger the object size is, the more pages we want on the partial
2459 * list to avoid pounding the page allocator excessively.
2461 set_min_partial(s, ilog2(s->size));
2462 s->refcount = 1;
2463 #ifdef CONFIG_NUMA
2464 s->remote_node_defrag_ratio = 1000;
2465 #endif
2466 if (!init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
2467 goto error;
2469 if (alloc_kmem_cache_cpus(s, gfpflags & ~SLUB_DMA))
2470 return 1;
2471 free_kmem_cache_nodes(s);
2472 error:
2473 if (flags & SLAB_PANIC)
2474 panic("Cannot create slab %s size=%lu realsize=%u "
2475 "order=%u offset=%u flags=%lx\n",
2476 s->name, (unsigned long)size, s->size, oo_order(s->oo),
2477 s->offset, flags);
2478 return 0;
2482 * Check if a given pointer is valid
2484 int kmem_ptr_validate(struct kmem_cache *s, const void *object)
2486 struct page *page;
2488 page = get_object_page(object);
2490 if (!page || s != page->slab)
2491 /* No slab or wrong slab */
2492 return 0;
2494 if (!check_valid_pointer(s, page, object))
2495 return 0;
2498 * We could also check if the object is on the slabs freelist.
2499 * But this would be too expensive and it seems that the main
2500 * purpose of kmem_ptr_valid() is to check if the object belongs
2501 * to a certain slab.
2503 return 1;
2505 EXPORT_SYMBOL(kmem_ptr_validate);
2508 * Determine the size of a slab object
2510 unsigned int kmem_cache_size(struct kmem_cache *s)
2512 return s->objsize;
2514 EXPORT_SYMBOL(kmem_cache_size);
2516 const char *kmem_cache_name(struct kmem_cache *s)
2518 return s->name;
2520 EXPORT_SYMBOL(kmem_cache_name);
2522 static void list_slab_objects(struct kmem_cache *s, struct page *page,
2523 const char *text)
2525 #ifdef CONFIG_SLUB_DEBUG
2526 void *addr = page_address(page);
2527 void *p;
2528 DECLARE_BITMAP(map, page->objects);
2530 bitmap_zero(map, page->objects);
2531 slab_err(s, page, "%s", text);
2532 slab_lock(page);
2533 for_each_free_object(p, s, page->freelist)
2534 set_bit(slab_index(p, s, addr), map);
2536 for_each_object(p, s, addr, page->objects) {
2538 if (!test_bit(slab_index(p, s, addr), map)) {
2539 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
2540 p, p - addr);
2541 print_tracking(s, p);
2544 slab_unlock(page);
2545 #endif
2549 * Attempt to free all partial slabs on a node.
2551 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
2553 unsigned long flags;
2554 struct page *page, *h;
2556 spin_lock_irqsave(&n->list_lock, flags);
2557 list_for_each_entry_safe(page, h, &n->partial, lru) {
2558 if (!page->inuse) {
2559 list_del(&page->lru);
2560 discard_slab(s, page);
2561 n->nr_partial--;
2562 } else {
2563 list_slab_objects(s, page,
2564 "Objects remaining on kmem_cache_close()");
2567 spin_unlock_irqrestore(&n->list_lock, flags);
2571 * Release all resources used by a slab cache.
2573 static inline int kmem_cache_close(struct kmem_cache *s)
2575 int node;
2577 flush_all(s);
2579 /* Attempt to free all objects */
2580 free_kmem_cache_cpus(s);
2581 for_each_node_state(node, N_NORMAL_MEMORY) {
2582 struct kmem_cache_node *n = get_node(s, node);
2584 free_partial(s, n);
2585 if (n->nr_partial || slabs_node(s, node))
2586 return 1;
2588 free_kmem_cache_nodes(s);
2589 return 0;
2593 * Close a cache and release the kmem_cache structure
2594 * (must be used for caches created using kmem_cache_create)
2596 void kmem_cache_destroy(struct kmem_cache *s)
2598 down_write(&slub_lock);
2599 s->refcount--;
2600 if (!s->refcount) {
2601 list_del(&s->list);
2602 up_write(&slub_lock);
2603 if (kmem_cache_close(s)) {
2604 printk(KERN_ERR "SLUB %s: %s called for cache that "
2605 "still has objects.\n", s->name, __func__);
2606 dump_stack();
2608 sysfs_slab_remove(s);
2609 } else
2610 up_write(&slub_lock);
2612 EXPORT_SYMBOL(kmem_cache_destroy);
2614 /********************************************************************
2615 * Kmalloc subsystem
2616 *******************************************************************/
2618 struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT] __cacheline_aligned;
2619 EXPORT_SYMBOL(kmalloc_caches);
2621 static int __init setup_slub_min_order(char *str)
2623 get_option(&str, &slub_min_order);
2625 return 1;
2628 __setup("slub_min_order=", setup_slub_min_order);
2630 static int __init setup_slub_max_order(char *str)
2632 get_option(&str, &slub_max_order);
2633 slub_max_order = min(slub_max_order, MAX_ORDER - 1);
2635 return 1;
2638 __setup("slub_max_order=", setup_slub_max_order);
2640 static int __init setup_slub_min_objects(char *str)
2642 get_option(&str, &slub_min_objects);
2644 return 1;
2647 __setup("slub_min_objects=", setup_slub_min_objects);
2649 static int __init setup_slub_nomerge(char *str)
2651 slub_nomerge = 1;
2652 return 1;
2655 __setup("slub_nomerge", setup_slub_nomerge);
2657 static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
2658 const char *name, int size, gfp_t gfp_flags)
2660 unsigned int flags = 0;
2662 if (gfp_flags & SLUB_DMA)
2663 flags = SLAB_CACHE_DMA;
2666 * This function is called with IRQs disabled during early-boot on
2667 * single CPU so there's no need to take slub_lock here.
2669 if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
2670 flags, NULL))
2671 goto panic;
2673 list_add(&s->list, &slab_caches);
2675 if (sysfs_slab_add(s))
2676 goto panic;
2677 return s;
2679 panic:
2680 panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
2683 #ifdef CONFIG_ZONE_DMA
2684 static struct kmem_cache *kmalloc_caches_dma[SLUB_PAGE_SHIFT];
2686 static void sysfs_add_func(struct work_struct *w)
2688 struct kmem_cache *s;
2690 down_write(&slub_lock);
2691 list_for_each_entry(s, &slab_caches, list) {
2692 if (s->flags & __SYSFS_ADD_DEFERRED) {
2693 s->flags &= ~__SYSFS_ADD_DEFERRED;
2694 sysfs_slab_add(s);
2697 up_write(&slub_lock);
2700 static DECLARE_WORK(sysfs_add_work, sysfs_add_func);
2702 static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
2704 struct kmem_cache *s;
2705 char *text;
2706 size_t realsize;
2707 unsigned long slabflags;
2709 s = kmalloc_caches_dma[index];
2710 if (s)
2711 return s;
2713 /* Dynamically create dma cache */
2714 if (flags & __GFP_WAIT)
2715 down_write(&slub_lock);
2716 else {
2717 if (!down_write_trylock(&slub_lock))
2718 goto out;
2721 if (kmalloc_caches_dma[index])
2722 goto unlock_out;
2724 realsize = kmalloc_caches[index].objsize;
2725 text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
2726 (unsigned int)realsize);
2727 s = kmalloc(kmem_size, flags & ~SLUB_DMA);
2730 * Must defer sysfs creation to a workqueue because we don't know
2731 * what context we are called from. Before sysfs comes up, we don't
2732 * need to do anything because our sysfs initcall will start by
2733 * adding all existing slabs to sysfs.
2735 slabflags = SLAB_CACHE_DMA|SLAB_NOTRACK;
2736 if (slab_state >= SYSFS)
2737 slabflags |= __SYSFS_ADD_DEFERRED;
2739 if (!s || !text || !kmem_cache_open(s, flags, text,
2740 realsize, ARCH_KMALLOC_MINALIGN, slabflags, NULL)) {
2741 kfree(s);
2742 kfree(text);
2743 goto unlock_out;
2746 list_add(&s->list, &slab_caches);
2747 kmalloc_caches_dma[index] = s;
2749 if (slab_state >= SYSFS)
2750 schedule_work(&sysfs_add_work);
2752 unlock_out:
2753 up_write(&slub_lock);
2754 out:
2755 return kmalloc_caches_dma[index];
2757 #endif
2760 * Conversion table for small slabs sizes / 8 to the index in the
2761 * kmalloc array. This is necessary for slabs < 192 since we have non power
2762 * of two cache sizes there. The size of larger slabs can be determined using
2763 * fls.
2765 static s8 size_index[24] = {
2766 3, /* 8 */
2767 4, /* 16 */
2768 5, /* 24 */
2769 5, /* 32 */
2770 6, /* 40 */
2771 6, /* 48 */
2772 6, /* 56 */
2773 6, /* 64 */
2774 1, /* 72 */
2775 1, /* 80 */
2776 1, /* 88 */
2777 1, /* 96 */
2778 7, /* 104 */
2779 7, /* 112 */
2780 7, /* 120 */
2781 7, /* 128 */
2782 2, /* 136 */
2783 2, /* 144 */
2784 2, /* 152 */
2785 2, /* 160 */
2786 2, /* 168 */
2787 2, /* 176 */
2788 2, /* 184 */
2789 2 /* 192 */
2792 static struct kmem_cache *get_slab(size_t size, gfp_t flags)
2794 int index;
2796 if (size <= 192) {
2797 if (!size)
2798 return ZERO_SIZE_PTR;
2800 index = size_index[(size - 1) / 8];
2801 } else
2802 index = fls(size - 1);
2804 #ifdef CONFIG_ZONE_DMA
2805 if (unlikely((flags & SLUB_DMA)))
2806 return dma_kmalloc_cache(index, flags);
2808 #endif
2809 return &kmalloc_caches[index];
2812 void *__kmalloc(size_t size, gfp_t flags)
2814 struct kmem_cache *s;
2815 void *ret;
2817 if (unlikely(size > SLUB_MAX_SIZE))
2818 return kmalloc_large(size, flags);
2820 s = get_slab(size, flags);
2822 if (unlikely(ZERO_OR_NULL_PTR(s)))
2823 return s;
2825 ret = slab_alloc(s, flags, -1, _RET_IP_);
2827 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
2829 return ret;
2831 EXPORT_SYMBOL(__kmalloc);
2833 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
2835 struct page *page;
2837 flags |= __GFP_COMP | __GFP_NOTRACK;
2838 page = alloc_pages_node(node, flags, get_order(size));
2839 if (page)
2840 return page_address(page);
2841 else
2842 return NULL;
2845 #ifdef CONFIG_NUMA
2846 void *__kmalloc_node(size_t size, gfp_t flags, int node)
2848 struct kmem_cache *s;
2849 void *ret;
2851 if (unlikely(size > SLUB_MAX_SIZE)) {
2852 ret = kmalloc_large_node(size, flags, node);
2854 trace_kmalloc_node(_RET_IP_, ret,
2855 size, PAGE_SIZE << get_order(size),
2856 flags, node);
2858 return ret;
2861 s = get_slab(size, flags);
2863 if (unlikely(ZERO_OR_NULL_PTR(s)))
2864 return s;
2866 ret = slab_alloc(s, flags, node, _RET_IP_);
2868 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
2870 return ret;
2872 EXPORT_SYMBOL(__kmalloc_node);
2873 #endif
2875 size_t ksize(const void *object)
2877 struct page *page;
2878 struct kmem_cache *s;
2880 if (unlikely(object == ZERO_SIZE_PTR))
2881 return 0;
2883 page = virt_to_head_page(object);
2885 if (unlikely(!PageSlab(page))) {
2886 WARN_ON(!PageCompound(page));
2887 return PAGE_SIZE << compound_order(page);
2889 s = page->slab;
2891 #ifdef CONFIG_SLUB_DEBUG
2893 * Debugging requires use of the padding between object
2894 * and whatever may come after it.
2896 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
2897 return s->objsize;
2899 #endif
2901 * If we have the need to store the freelist pointer
2902 * back there or track user information then we can
2903 * only use the space before that information.
2905 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
2906 return s->inuse;
2908 * Else we can use all the padding etc for the allocation
2910 return s->size;
2912 EXPORT_SYMBOL(ksize);
2914 void kfree(const void *x)
2916 struct page *page;
2917 void *object = (void *)x;
2919 trace_kfree(_RET_IP_, x);
2921 if (unlikely(ZERO_OR_NULL_PTR(x)))
2922 return;
2924 page = virt_to_head_page(x);
2925 if (unlikely(!PageSlab(page))) {
2926 BUG_ON(!PageCompound(page));
2927 put_page(page);
2928 return;
2930 slab_free(page->slab, page, object, _RET_IP_);
2932 EXPORT_SYMBOL(kfree);
2935 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2936 * the remaining slabs by the number of items in use. The slabs with the
2937 * most items in use come first. New allocations will then fill those up
2938 * and thus they can be removed from the partial lists.
2940 * The slabs with the least items are placed last. This results in them
2941 * being allocated from last increasing the chance that the last objects
2942 * are freed in them.
2944 int kmem_cache_shrink(struct kmem_cache *s)
2946 int node;
2947 int i;
2948 struct kmem_cache_node *n;
2949 struct page *page;
2950 struct page *t;
2951 int objects = oo_objects(s->max);
2952 struct list_head *slabs_by_inuse =
2953 kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
2954 unsigned long flags;
2956 if (!slabs_by_inuse)
2957 return -ENOMEM;
2959 flush_all(s);
2960 for_each_node_state(node, N_NORMAL_MEMORY) {
2961 n = get_node(s, node);
2963 if (!n->nr_partial)
2964 continue;
2966 for (i = 0; i < objects; i++)
2967 INIT_LIST_HEAD(slabs_by_inuse + i);
2969 spin_lock_irqsave(&n->list_lock, flags);
2972 * Build lists indexed by the items in use in each slab.
2974 * Note that concurrent frees may occur while we hold the
2975 * list_lock. page->inuse here is the upper limit.
2977 list_for_each_entry_safe(page, t, &n->partial, lru) {
2978 if (!page->inuse && slab_trylock(page)) {
2980 * Must hold slab lock here because slab_free
2981 * may have freed the last object and be
2982 * waiting to release the slab.
2984 list_del(&page->lru);
2985 n->nr_partial--;
2986 slab_unlock(page);
2987 discard_slab(s, page);
2988 } else {
2989 list_move(&page->lru,
2990 slabs_by_inuse + page->inuse);
2995 * Rebuild the partial list with the slabs filled up most
2996 * first and the least used slabs at the end.
2998 for (i = objects - 1; i >= 0; i--)
2999 list_splice(slabs_by_inuse + i, n->partial.prev);
3001 spin_unlock_irqrestore(&n->list_lock, flags);
3004 kfree(slabs_by_inuse);
3005 return 0;
3007 EXPORT_SYMBOL(kmem_cache_shrink);
3009 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
3010 static int slab_mem_going_offline_callback(void *arg)
3012 struct kmem_cache *s;
3014 down_read(&slub_lock);
3015 list_for_each_entry(s, &slab_caches, list)
3016 kmem_cache_shrink(s);
3017 up_read(&slub_lock);
3019 return 0;
3022 static void slab_mem_offline_callback(void *arg)
3024 struct kmem_cache_node *n;
3025 struct kmem_cache *s;
3026 struct memory_notify *marg = arg;
3027 int offline_node;
3029 offline_node = marg->status_change_nid;
3032 * If the node still has available memory. we need kmem_cache_node
3033 * for it yet.
3035 if (offline_node < 0)
3036 return;
3038 down_read(&slub_lock);
3039 list_for_each_entry(s, &slab_caches, list) {
3040 n = get_node(s, offline_node);
3041 if (n) {
3043 * if n->nr_slabs > 0, slabs still exist on the node
3044 * that is going down. We were unable to free them,
3045 * and offline_pages() function shoudn't call this
3046 * callback. So, we must fail.
3048 BUG_ON(slabs_node(s, offline_node));
3050 s->node[offline_node] = NULL;
3051 kmem_cache_free(kmalloc_caches, n);
3054 up_read(&slub_lock);
3057 static int slab_mem_going_online_callback(void *arg)
3059 struct kmem_cache_node *n;
3060 struct kmem_cache *s;
3061 struct memory_notify *marg = arg;
3062 int nid = marg->status_change_nid;
3063 int ret = 0;
3066 * If the node's memory is already available, then kmem_cache_node is
3067 * already created. Nothing to do.
3069 if (nid < 0)
3070 return 0;
3073 * We are bringing a node online. No memory is available yet. We must
3074 * allocate a kmem_cache_node structure in order to bring the node
3075 * online.
3077 down_read(&slub_lock);
3078 list_for_each_entry(s, &slab_caches, list) {
3080 * XXX: kmem_cache_alloc_node will fallback to other nodes
3081 * since memory is not yet available from the node that
3082 * is brought up.
3084 n = kmem_cache_alloc(kmalloc_caches, GFP_KERNEL);
3085 if (!n) {
3086 ret = -ENOMEM;
3087 goto out;
3089 init_kmem_cache_node(n, s);
3090 s->node[nid] = n;
3092 out:
3093 up_read(&slub_lock);
3094 return ret;
3097 static int slab_memory_callback(struct notifier_block *self,
3098 unsigned long action, void *arg)
3100 int ret = 0;
3102 switch (action) {
3103 case MEM_GOING_ONLINE:
3104 ret = slab_mem_going_online_callback(arg);
3105 break;
3106 case MEM_GOING_OFFLINE:
3107 ret = slab_mem_going_offline_callback(arg);
3108 break;
3109 case MEM_OFFLINE:
3110 case MEM_CANCEL_ONLINE:
3111 slab_mem_offline_callback(arg);
3112 break;
3113 case MEM_ONLINE:
3114 case MEM_CANCEL_OFFLINE:
3115 break;
3117 if (ret)
3118 ret = notifier_from_errno(ret);
3119 else
3120 ret = NOTIFY_OK;
3121 return ret;
3124 #endif /* CONFIG_MEMORY_HOTPLUG */
3126 /********************************************************************
3127 * Basic setup of slabs
3128 *******************************************************************/
3130 void __init kmem_cache_init(void)
3132 int i;
3133 int caches = 0;
3135 init_alloc_cpu();
3137 #ifdef CONFIG_NUMA
3139 * Must first have the slab cache available for the allocations of the
3140 * struct kmem_cache_node's. There is special bootstrap code in
3141 * kmem_cache_open for slab_state == DOWN.
3143 create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node",
3144 sizeof(struct kmem_cache_node), GFP_NOWAIT);
3145 kmalloc_caches[0].refcount = -1;
3146 caches++;
3148 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3149 #endif
3151 /* Able to allocate the per node structures */
3152 slab_state = PARTIAL;
3154 /* Caches that are not of the two-to-the-power-of size */
3155 if (KMALLOC_MIN_SIZE <= 64) {
3156 create_kmalloc_cache(&kmalloc_caches[1],
3157 "kmalloc-96", 96, GFP_NOWAIT);
3158 caches++;
3159 create_kmalloc_cache(&kmalloc_caches[2],
3160 "kmalloc-192", 192, GFP_NOWAIT);
3161 caches++;
3164 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3165 create_kmalloc_cache(&kmalloc_caches[i],
3166 "kmalloc", 1 << i, GFP_NOWAIT);
3167 caches++;
3172 * Patch up the size_index table if we have strange large alignment
3173 * requirements for the kmalloc array. This is only the case for
3174 * MIPS it seems. The standard arches will not generate any code here.
3176 * Largest permitted alignment is 256 bytes due to the way we
3177 * handle the index determination for the smaller caches.
3179 * Make sure that nothing crazy happens if someone starts tinkering
3180 * around with ARCH_KMALLOC_MINALIGN
3182 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3183 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3185 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8)
3186 size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW;
3188 if (KMALLOC_MIN_SIZE == 128) {
3190 * The 192 byte sized cache is not used if the alignment
3191 * is 128 byte. Redirect kmalloc to use the 256 byte cache
3192 * instead.
3194 for (i = 128 + 8; i <= 192; i += 8)
3195 size_index[(i - 1) / 8] = 8;
3198 slab_state = UP;
3200 /* Provide the correct kmalloc names now that the caches are up */
3201 for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++)
3202 kmalloc_caches[i]. name =
3203 kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
3205 #ifdef CONFIG_SMP
3206 register_cpu_notifier(&slab_notifier);
3207 kmem_size = offsetof(struct kmem_cache, cpu_slab) +
3208 nr_cpu_ids * sizeof(struct kmem_cache_cpu *);
3209 #else
3210 kmem_size = sizeof(struct kmem_cache);
3211 #endif
3213 printk(KERN_INFO
3214 "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3215 " CPUs=%d, Nodes=%d\n",
3216 caches, cache_line_size(),
3217 slub_min_order, slub_max_order, slub_min_objects,
3218 nr_cpu_ids, nr_node_ids);
3221 void __init kmem_cache_init_late(void)
3224 * Interrupts are enabled now so all GFP allocations are safe.
3226 slab_gfp_mask = __GFP_BITS_MASK;
3230 * Find a mergeable slab cache
3232 static int slab_unmergeable(struct kmem_cache *s)
3234 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3235 return 1;
3237 if (s->ctor)
3238 return 1;
3241 * We may have set a slab to be unmergeable during bootstrap.
3243 if (s->refcount < 0)
3244 return 1;
3246 return 0;
3249 static struct kmem_cache *find_mergeable(size_t size,
3250 size_t align, unsigned long flags, const char *name,
3251 void (*ctor)(void *))
3253 struct kmem_cache *s;
3255 if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3256 return NULL;
3258 if (ctor)
3259 return NULL;
3261 size = ALIGN(size, sizeof(void *));
3262 align = calculate_alignment(flags, align, size);
3263 size = ALIGN(size, align);
3264 flags = kmem_cache_flags(size, flags, name, NULL);
3266 list_for_each_entry(s, &slab_caches, list) {
3267 if (slab_unmergeable(s))
3268 continue;
3270 if (size > s->size)
3271 continue;
3273 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3274 continue;
3276 * Check if alignment is compatible.
3277 * Courtesy of Adrian Drzewiecki
3279 if ((s->size & ~(align - 1)) != s->size)
3280 continue;
3282 if (s->size - size >= sizeof(void *))
3283 continue;
3285 return s;
3287 return NULL;
3290 struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3291 size_t align, unsigned long flags, void (*ctor)(void *))
3293 struct kmem_cache *s;
3295 down_write(&slub_lock);
3296 s = find_mergeable(size, align, flags, name, ctor);
3297 if (s) {
3298 int cpu;
3300 s->refcount++;
3302 * Adjust the object sizes so that we clear
3303 * the complete object on kzalloc.
3305 s->objsize = max(s->objsize, (int)size);
3308 * And then we need to update the object size in the
3309 * per cpu structures
3311 for_each_online_cpu(cpu)
3312 get_cpu_slab(s, cpu)->objsize = s->objsize;
3314 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3315 up_write(&slub_lock);
3317 if (sysfs_slab_alias(s, name)) {
3318 down_write(&slub_lock);
3319 s->refcount--;
3320 up_write(&slub_lock);
3321 goto err;
3323 return s;
3326 s = kmalloc(kmem_size, GFP_KERNEL);
3327 if (s) {
3328 if (kmem_cache_open(s, GFP_KERNEL, name,
3329 size, align, flags, ctor)) {
3330 list_add(&s->list, &slab_caches);
3331 up_write(&slub_lock);
3332 if (sysfs_slab_add(s)) {
3333 down_write(&slub_lock);
3334 list_del(&s->list);
3335 up_write(&slub_lock);
3336 kfree(s);
3337 goto err;
3339 return s;
3341 kfree(s);
3343 up_write(&slub_lock);
3345 err:
3346 if (flags & SLAB_PANIC)
3347 panic("Cannot create slabcache %s\n", name);
3348 else
3349 s = NULL;
3350 return s;
3352 EXPORT_SYMBOL(kmem_cache_create);
3354 #ifdef CONFIG_SMP
3356 * Use the cpu notifier to insure that the cpu slabs are flushed when
3357 * necessary.
3359 static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3360 unsigned long action, void *hcpu)
3362 long cpu = (long)hcpu;
3363 struct kmem_cache *s;
3364 unsigned long flags;
3366 switch (action) {
3367 case CPU_UP_PREPARE:
3368 case CPU_UP_PREPARE_FROZEN:
3369 init_alloc_cpu_cpu(cpu);
3370 down_read(&slub_lock);
3371 list_for_each_entry(s, &slab_caches, list)
3372 s->cpu_slab[cpu] = alloc_kmem_cache_cpu(s, cpu,
3373 GFP_KERNEL);
3374 up_read(&slub_lock);
3375 break;
3377 case CPU_UP_CANCELED:
3378 case CPU_UP_CANCELED_FROZEN:
3379 case CPU_DEAD:
3380 case CPU_DEAD_FROZEN:
3381 down_read(&slub_lock);
3382 list_for_each_entry(s, &slab_caches, list) {
3383 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3385 local_irq_save(flags);
3386 __flush_cpu_slab(s, cpu);
3387 local_irq_restore(flags);
3388 free_kmem_cache_cpu(c, cpu);
3389 s->cpu_slab[cpu] = NULL;
3391 up_read(&slub_lock);
3392 break;
3393 default:
3394 break;
3396 return NOTIFY_OK;
3399 static struct notifier_block __cpuinitdata slab_notifier = {
3400 .notifier_call = slab_cpuup_callback
3403 #endif
3405 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
3407 struct kmem_cache *s;
3408 void *ret;
3410 if (unlikely(size > SLUB_MAX_SIZE))
3411 return kmalloc_large(size, gfpflags);
3413 s = get_slab(size, gfpflags);
3415 if (unlikely(ZERO_OR_NULL_PTR(s)))
3416 return s;
3418 ret = slab_alloc(s, gfpflags, -1, caller);
3420 /* Honor the call site pointer we recieved. */
3421 trace_kmalloc(caller, ret, size, s->size, gfpflags);
3423 return ret;
3426 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3427 int node, unsigned long caller)
3429 struct kmem_cache *s;
3430 void *ret;
3432 if (unlikely(size > SLUB_MAX_SIZE))
3433 return kmalloc_large_node(size, gfpflags, node);
3435 s = get_slab(size, gfpflags);
3437 if (unlikely(ZERO_OR_NULL_PTR(s)))
3438 return s;
3440 ret = slab_alloc(s, gfpflags, node, caller);
3442 /* Honor the call site pointer we recieved. */
3443 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
3445 return ret;
3448 #ifdef CONFIG_SLUB_DEBUG
3449 static int count_inuse(struct page *page)
3451 return page->inuse;
3454 static int count_total(struct page *page)
3456 return page->objects;
3459 static int validate_slab(struct kmem_cache *s, struct page *page,
3460 unsigned long *map)
3462 void *p;
3463 void *addr = page_address(page);
3465 if (!check_slab(s, page) ||
3466 !on_freelist(s, page, NULL))
3467 return 0;
3469 /* Now we know that a valid freelist exists */
3470 bitmap_zero(map, page->objects);
3472 for_each_free_object(p, s, page->freelist) {
3473 set_bit(slab_index(p, s, addr), map);
3474 if (!check_object(s, page, p, 0))
3475 return 0;
3478 for_each_object(p, s, addr, page->objects)
3479 if (!test_bit(slab_index(p, s, addr), map))
3480 if (!check_object(s, page, p, 1))
3481 return 0;
3482 return 1;
3485 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3486 unsigned long *map)
3488 if (slab_trylock(page)) {
3489 validate_slab(s, page, map);
3490 slab_unlock(page);
3491 } else
3492 printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
3493 s->name, page);
3495 if (s->flags & DEBUG_DEFAULT_FLAGS) {
3496 if (!PageSlubDebug(page))
3497 printk(KERN_ERR "SLUB %s: SlubDebug not set "
3498 "on slab 0x%p\n", s->name, page);
3499 } else {
3500 if (PageSlubDebug(page))
3501 printk(KERN_ERR "SLUB %s: SlubDebug set on "
3502 "slab 0x%p\n", s->name, page);
3506 static int validate_slab_node(struct kmem_cache *s,
3507 struct kmem_cache_node *n, unsigned long *map)
3509 unsigned long count = 0;
3510 struct page *page;
3511 unsigned long flags;
3513 spin_lock_irqsave(&n->list_lock, flags);
3515 list_for_each_entry(page, &n->partial, lru) {
3516 validate_slab_slab(s, page, map);
3517 count++;
3519 if (count != n->nr_partial)
3520 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3521 "counter=%ld\n", s->name, count, n->nr_partial);
3523 if (!(s->flags & SLAB_STORE_USER))
3524 goto out;
3526 list_for_each_entry(page, &n->full, lru) {
3527 validate_slab_slab(s, page, map);
3528 count++;
3530 if (count != atomic_long_read(&n->nr_slabs))
3531 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3532 "counter=%ld\n", s->name, count,
3533 atomic_long_read(&n->nr_slabs));
3535 out:
3536 spin_unlock_irqrestore(&n->list_lock, flags);
3537 return count;
3540 static long validate_slab_cache(struct kmem_cache *s)
3542 int node;
3543 unsigned long count = 0;
3544 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
3545 sizeof(unsigned long), GFP_KERNEL);
3547 if (!map)
3548 return -ENOMEM;
3550 flush_all(s);
3551 for_each_node_state(node, N_NORMAL_MEMORY) {
3552 struct kmem_cache_node *n = get_node(s, node);
3554 count += validate_slab_node(s, n, map);
3556 kfree(map);
3557 return count;
3560 #ifdef SLUB_RESILIENCY_TEST
3561 static void resiliency_test(void)
3563 u8 *p;
3565 printk(KERN_ERR "SLUB resiliency testing\n");
3566 printk(KERN_ERR "-----------------------\n");
3567 printk(KERN_ERR "A. Corruption after allocation\n");
3569 p = kzalloc(16, GFP_KERNEL);
3570 p[16] = 0x12;
3571 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
3572 " 0x12->0x%p\n\n", p + 16);
3574 validate_slab_cache(kmalloc_caches + 4);
3576 /* Hmmm... The next two are dangerous */
3577 p = kzalloc(32, GFP_KERNEL);
3578 p[32 + sizeof(void *)] = 0x34;
3579 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
3580 " 0x34 -> -0x%p\n", p);
3581 printk(KERN_ERR
3582 "If allocated object is overwritten then not detectable\n\n");
3584 validate_slab_cache(kmalloc_caches + 5);
3585 p = kzalloc(64, GFP_KERNEL);
3586 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
3587 *p = 0x56;
3588 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
3590 printk(KERN_ERR
3591 "If allocated object is overwritten then not detectable\n\n");
3592 validate_slab_cache(kmalloc_caches + 6);
3594 printk(KERN_ERR "\nB. Corruption after free\n");
3595 p = kzalloc(128, GFP_KERNEL);
3596 kfree(p);
3597 *p = 0x78;
3598 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
3599 validate_slab_cache(kmalloc_caches + 7);
3601 p = kzalloc(256, GFP_KERNEL);
3602 kfree(p);
3603 p[50] = 0x9a;
3604 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
3606 validate_slab_cache(kmalloc_caches + 8);
3608 p = kzalloc(512, GFP_KERNEL);
3609 kfree(p);
3610 p[512] = 0xab;
3611 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
3612 validate_slab_cache(kmalloc_caches + 9);
3614 #else
3615 static void resiliency_test(void) {};
3616 #endif
3619 * Generate lists of code addresses where slabcache objects are allocated
3620 * and freed.
3623 struct location {
3624 unsigned long count;
3625 unsigned long addr;
3626 long long sum_time;
3627 long min_time;
3628 long max_time;
3629 long min_pid;
3630 long max_pid;
3631 DECLARE_BITMAP(cpus, NR_CPUS);
3632 nodemask_t nodes;
3635 struct loc_track {
3636 unsigned long max;
3637 unsigned long count;
3638 struct location *loc;
3641 static void free_loc_track(struct loc_track *t)
3643 if (t->max)
3644 free_pages((unsigned long)t->loc,
3645 get_order(sizeof(struct location) * t->max));
3648 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
3650 struct location *l;
3651 int order;
3653 order = get_order(sizeof(struct location) * max);
3655 l = (void *)__get_free_pages(flags, order);
3656 if (!l)
3657 return 0;
3659 if (t->count) {
3660 memcpy(l, t->loc, sizeof(struct location) * t->count);
3661 free_loc_track(t);
3663 t->max = max;
3664 t->loc = l;
3665 return 1;
3668 static int add_location(struct loc_track *t, struct kmem_cache *s,
3669 const struct track *track)
3671 long start, end, pos;
3672 struct location *l;
3673 unsigned long caddr;
3674 unsigned long age = jiffies - track->when;
3676 start = -1;
3677 end = t->count;
3679 for ( ; ; ) {
3680 pos = start + (end - start + 1) / 2;
3683 * There is nothing at "end". If we end up there
3684 * we need to add something to before end.
3686 if (pos == end)
3687 break;
3689 caddr = t->loc[pos].addr;
3690 if (track->addr == caddr) {
3692 l = &t->loc[pos];
3693 l->count++;
3694 if (track->when) {
3695 l->sum_time += age;
3696 if (age < l->min_time)
3697 l->min_time = age;
3698 if (age > l->max_time)
3699 l->max_time = age;
3701 if (track->pid < l->min_pid)
3702 l->min_pid = track->pid;
3703 if (track->pid > l->max_pid)
3704 l->max_pid = track->pid;
3706 cpumask_set_cpu(track->cpu,
3707 to_cpumask(l->cpus));
3709 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3710 return 1;
3713 if (track->addr < caddr)
3714 end = pos;
3715 else
3716 start = pos;
3720 * Not found. Insert new tracking element.
3722 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
3723 return 0;
3725 l = t->loc + pos;
3726 if (pos < t->count)
3727 memmove(l + 1, l,
3728 (t->count - pos) * sizeof(struct location));
3729 t->count++;
3730 l->count = 1;
3731 l->addr = track->addr;
3732 l->sum_time = age;
3733 l->min_time = age;
3734 l->max_time = age;
3735 l->min_pid = track->pid;
3736 l->max_pid = track->pid;
3737 cpumask_clear(to_cpumask(l->cpus));
3738 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
3739 nodes_clear(l->nodes);
3740 node_set(page_to_nid(virt_to_page(track)), l->nodes);
3741 return 1;
3744 static void process_slab(struct loc_track *t, struct kmem_cache *s,
3745 struct page *page, enum track_item alloc)
3747 void *addr = page_address(page);
3748 DECLARE_BITMAP(map, page->objects);
3749 void *p;
3751 bitmap_zero(map, page->objects);
3752 for_each_free_object(p, s, page->freelist)
3753 set_bit(slab_index(p, s, addr), map);
3755 for_each_object(p, s, addr, page->objects)
3756 if (!test_bit(slab_index(p, s, addr), map))
3757 add_location(t, s, get_track(s, p, alloc));
3760 static int list_locations(struct kmem_cache *s, char *buf,
3761 enum track_item alloc)
3763 int len = 0;
3764 unsigned long i;
3765 struct loc_track t = { 0, 0, NULL };
3766 int node;
3768 if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
3769 GFP_TEMPORARY))
3770 return sprintf(buf, "Out of memory\n");
3772 /* Push back cpu slabs */
3773 flush_all(s);
3775 for_each_node_state(node, N_NORMAL_MEMORY) {
3776 struct kmem_cache_node *n = get_node(s, node);
3777 unsigned long flags;
3778 struct page *page;
3780 if (!atomic_long_read(&n->nr_slabs))
3781 continue;
3783 spin_lock_irqsave(&n->list_lock, flags);
3784 list_for_each_entry(page, &n->partial, lru)
3785 process_slab(&t, s, page, alloc);
3786 list_for_each_entry(page, &n->full, lru)
3787 process_slab(&t, s, page, alloc);
3788 spin_unlock_irqrestore(&n->list_lock, flags);
3791 for (i = 0; i < t.count; i++) {
3792 struct location *l = &t.loc[i];
3794 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
3795 break;
3796 len += sprintf(buf + len, "%7ld ", l->count);
3798 if (l->addr)
3799 len += sprint_symbol(buf + len, (unsigned long)l->addr);
3800 else
3801 len += sprintf(buf + len, "<not-available>");
3803 if (l->sum_time != l->min_time) {
3804 len += sprintf(buf + len, " age=%ld/%ld/%ld",
3805 l->min_time,
3806 (long)div_u64(l->sum_time, l->count),
3807 l->max_time);
3808 } else
3809 len += sprintf(buf + len, " age=%ld",
3810 l->min_time);
3812 if (l->min_pid != l->max_pid)
3813 len += sprintf(buf + len, " pid=%ld-%ld",
3814 l->min_pid, l->max_pid);
3815 else
3816 len += sprintf(buf + len, " pid=%ld",
3817 l->min_pid);
3819 if (num_online_cpus() > 1 &&
3820 !cpumask_empty(to_cpumask(l->cpus)) &&
3821 len < PAGE_SIZE - 60) {
3822 len += sprintf(buf + len, " cpus=");
3823 len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3824 to_cpumask(l->cpus));
3827 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
3828 len < PAGE_SIZE - 60) {
3829 len += sprintf(buf + len, " nodes=");
3830 len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
3831 l->nodes);
3834 len += sprintf(buf + len, "\n");
3837 free_loc_track(&t);
3838 if (!t.count)
3839 len += sprintf(buf, "No data\n");
3840 return len;
3843 enum slab_stat_type {
3844 SL_ALL, /* All slabs */
3845 SL_PARTIAL, /* Only partially allocated slabs */
3846 SL_CPU, /* Only slabs used for cpu caches */
3847 SL_OBJECTS, /* Determine allocated objects not slabs */
3848 SL_TOTAL /* Determine object capacity not slabs */
3851 #define SO_ALL (1 << SL_ALL)
3852 #define SO_PARTIAL (1 << SL_PARTIAL)
3853 #define SO_CPU (1 << SL_CPU)
3854 #define SO_OBJECTS (1 << SL_OBJECTS)
3855 #define SO_TOTAL (1 << SL_TOTAL)
3857 static ssize_t show_slab_objects(struct kmem_cache *s,
3858 char *buf, unsigned long flags)
3860 unsigned long total = 0;
3861 int node;
3862 int x;
3863 unsigned long *nodes;
3864 unsigned long *per_cpu;
3866 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
3867 if (!nodes)
3868 return -ENOMEM;
3869 per_cpu = nodes + nr_node_ids;
3871 if (flags & SO_CPU) {
3872 int cpu;
3874 for_each_possible_cpu(cpu) {
3875 struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
3877 if (!c || c->node < 0)
3878 continue;
3880 if (c->page) {
3881 if (flags & SO_TOTAL)
3882 x = c->page->objects;
3883 else if (flags & SO_OBJECTS)
3884 x = c->page->inuse;
3885 else
3886 x = 1;
3888 total += x;
3889 nodes[c->node] += x;
3891 per_cpu[c->node]++;
3895 if (flags & SO_ALL) {
3896 for_each_node_state(node, N_NORMAL_MEMORY) {
3897 struct kmem_cache_node *n = get_node(s, node);
3899 if (flags & SO_TOTAL)
3900 x = atomic_long_read(&n->total_objects);
3901 else if (flags & SO_OBJECTS)
3902 x = atomic_long_read(&n->total_objects) -
3903 count_partial(n, count_free);
3905 else
3906 x = atomic_long_read(&n->nr_slabs);
3907 total += x;
3908 nodes[node] += x;
3911 } else if (flags & SO_PARTIAL) {
3912 for_each_node_state(node, N_NORMAL_MEMORY) {
3913 struct kmem_cache_node *n = get_node(s, node);
3915 if (flags & SO_TOTAL)
3916 x = count_partial(n, count_total);
3917 else if (flags & SO_OBJECTS)
3918 x = count_partial(n, count_inuse);
3919 else
3920 x = n->nr_partial;
3921 total += x;
3922 nodes[node] += x;
3925 x = sprintf(buf, "%lu", total);
3926 #ifdef CONFIG_NUMA
3927 for_each_node_state(node, N_NORMAL_MEMORY)
3928 if (nodes[node])
3929 x += sprintf(buf + x, " N%d=%lu",
3930 node, nodes[node]);
3931 #endif
3932 kfree(nodes);
3933 return x + sprintf(buf + x, "\n");
3936 static int any_slab_objects(struct kmem_cache *s)
3938 int node;
3940 for_each_online_node(node) {
3941 struct kmem_cache_node *n = get_node(s, node);
3943 if (!n)
3944 continue;
3946 if (atomic_long_read(&n->total_objects))
3947 return 1;
3949 return 0;
3952 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3953 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3955 struct slab_attribute {
3956 struct attribute attr;
3957 ssize_t (*show)(struct kmem_cache *s, char *buf);
3958 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
3961 #define SLAB_ATTR_RO(_name) \
3962 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3964 #define SLAB_ATTR(_name) \
3965 static struct slab_attribute _name##_attr = \
3966 __ATTR(_name, 0644, _name##_show, _name##_store)
3968 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
3970 return sprintf(buf, "%d\n", s->size);
3972 SLAB_ATTR_RO(slab_size);
3974 static ssize_t align_show(struct kmem_cache *s, char *buf)
3976 return sprintf(buf, "%d\n", s->align);
3978 SLAB_ATTR_RO(align);
3980 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
3982 return sprintf(buf, "%d\n", s->objsize);
3984 SLAB_ATTR_RO(object_size);
3986 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
3988 return sprintf(buf, "%d\n", oo_objects(s->oo));
3990 SLAB_ATTR_RO(objs_per_slab);
3992 static ssize_t order_store(struct kmem_cache *s,
3993 const char *buf, size_t length)
3995 unsigned long order;
3996 int err;
3998 err = strict_strtoul(buf, 10, &order);
3999 if (err)
4000 return err;
4002 if (order > slub_max_order || order < slub_min_order)
4003 return -EINVAL;
4005 calculate_sizes(s, order);
4006 return length;
4009 static ssize_t order_show(struct kmem_cache *s, char *buf)
4011 return sprintf(buf, "%d\n", oo_order(s->oo));
4013 SLAB_ATTR(order);
4015 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4017 return sprintf(buf, "%lu\n", s->min_partial);
4020 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4021 size_t length)
4023 unsigned long min;
4024 int err;
4026 err = strict_strtoul(buf, 10, &min);
4027 if (err)
4028 return err;
4030 set_min_partial(s, min);
4031 return length;
4033 SLAB_ATTR(min_partial);
4035 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4037 if (s->ctor) {
4038 int n = sprint_symbol(buf, (unsigned long)s->ctor);
4040 return n + sprintf(buf + n, "\n");
4042 return 0;
4044 SLAB_ATTR_RO(ctor);
4046 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4048 return sprintf(buf, "%d\n", s->refcount - 1);
4050 SLAB_ATTR_RO(aliases);
4052 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4054 return show_slab_objects(s, buf, SO_ALL);
4056 SLAB_ATTR_RO(slabs);
4058 static ssize_t partial_show(struct kmem_cache *s, char *buf)
4060 return show_slab_objects(s, buf, SO_PARTIAL);
4062 SLAB_ATTR_RO(partial);
4064 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4066 return show_slab_objects(s, buf, SO_CPU);
4068 SLAB_ATTR_RO(cpu_slabs);
4070 static ssize_t objects_show(struct kmem_cache *s, char *buf)
4072 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4074 SLAB_ATTR_RO(objects);
4076 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4078 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4080 SLAB_ATTR_RO(objects_partial);
4082 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4084 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4086 SLAB_ATTR_RO(total_objects);
4088 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4090 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4093 static ssize_t sanity_checks_store(struct kmem_cache *s,
4094 const char *buf, size_t length)
4096 s->flags &= ~SLAB_DEBUG_FREE;
4097 if (buf[0] == '1')
4098 s->flags |= SLAB_DEBUG_FREE;
4099 return length;
4101 SLAB_ATTR(sanity_checks);
4103 static ssize_t trace_show(struct kmem_cache *s, char *buf)
4105 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4108 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4109 size_t length)
4111 s->flags &= ~SLAB_TRACE;
4112 if (buf[0] == '1')
4113 s->flags |= SLAB_TRACE;
4114 return length;
4116 SLAB_ATTR(trace);
4118 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4120 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4123 static ssize_t reclaim_account_store(struct kmem_cache *s,
4124 const char *buf, size_t length)
4126 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4127 if (buf[0] == '1')
4128 s->flags |= SLAB_RECLAIM_ACCOUNT;
4129 return length;
4131 SLAB_ATTR(reclaim_account);
4133 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4135 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4137 SLAB_ATTR_RO(hwcache_align);
4139 #ifdef CONFIG_ZONE_DMA
4140 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4142 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4144 SLAB_ATTR_RO(cache_dma);
4145 #endif
4147 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4149 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4151 SLAB_ATTR_RO(destroy_by_rcu);
4153 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4155 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4158 static ssize_t red_zone_store(struct kmem_cache *s,
4159 const char *buf, size_t length)
4161 if (any_slab_objects(s))
4162 return -EBUSY;
4164 s->flags &= ~SLAB_RED_ZONE;
4165 if (buf[0] == '1')
4166 s->flags |= SLAB_RED_ZONE;
4167 calculate_sizes(s, -1);
4168 return length;
4170 SLAB_ATTR(red_zone);
4172 static ssize_t poison_show(struct kmem_cache *s, char *buf)
4174 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4177 static ssize_t poison_store(struct kmem_cache *s,
4178 const char *buf, size_t length)
4180 if (any_slab_objects(s))
4181 return -EBUSY;
4183 s->flags &= ~SLAB_POISON;
4184 if (buf[0] == '1')
4185 s->flags |= SLAB_POISON;
4186 calculate_sizes(s, -1);
4187 return length;
4189 SLAB_ATTR(poison);
4191 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4193 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4196 static ssize_t store_user_store(struct kmem_cache *s,
4197 const char *buf, size_t length)
4199 if (any_slab_objects(s))
4200 return -EBUSY;
4202 s->flags &= ~SLAB_STORE_USER;
4203 if (buf[0] == '1')
4204 s->flags |= SLAB_STORE_USER;
4205 calculate_sizes(s, -1);
4206 return length;
4208 SLAB_ATTR(store_user);
4210 static ssize_t validate_show(struct kmem_cache *s, char *buf)
4212 return 0;
4215 static ssize_t validate_store(struct kmem_cache *s,
4216 const char *buf, size_t length)
4218 int ret = -EINVAL;
4220 if (buf[0] == '1') {
4221 ret = validate_slab_cache(s);
4222 if (ret >= 0)
4223 ret = length;
4225 return ret;
4227 SLAB_ATTR(validate);
4229 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4231 return 0;
4234 static ssize_t shrink_store(struct kmem_cache *s,
4235 const char *buf, size_t length)
4237 if (buf[0] == '1') {
4238 int rc = kmem_cache_shrink(s);
4240 if (rc)
4241 return rc;
4242 } else
4243 return -EINVAL;
4244 return length;
4246 SLAB_ATTR(shrink);
4248 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4250 if (!(s->flags & SLAB_STORE_USER))
4251 return -ENOSYS;
4252 return list_locations(s, buf, TRACK_ALLOC);
4254 SLAB_ATTR_RO(alloc_calls);
4256 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4258 if (!(s->flags & SLAB_STORE_USER))
4259 return -ENOSYS;
4260 return list_locations(s, buf, TRACK_FREE);
4262 SLAB_ATTR_RO(free_calls);
4264 #ifdef CONFIG_NUMA
4265 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4267 return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4270 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4271 const char *buf, size_t length)
4273 unsigned long ratio;
4274 int err;
4276 err = strict_strtoul(buf, 10, &ratio);
4277 if (err)
4278 return err;
4280 if (ratio <= 100)
4281 s->remote_node_defrag_ratio = ratio * 10;
4283 return length;
4285 SLAB_ATTR(remote_node_defrag_ratio);
4286 #endif
4288 #ifdef CONFIG_SLUB_STATS
4289 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4291 unsigned long sum = 0;
4292 int cpu;
4293 int len;
4294 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4296 if (!data)
4297 return -ENOMEM;
4299 for_each_online_cpu(cpu) {
4300 unsigned x = get_cpu_slab(s, cpu)->stat[si];
4302 data[cpu] = x;
4303 sum += x;
4306 len = sprintf(buf, "%lu", sum);
4308 #ifdef CONFIG_SMP
4309 for_each_online_cpu(cpu) {
4310 if (data[cpu] && len < PAGE_SIZE - 20)
4311 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4313 #endif
4314 kfree(data);
4315 return len + sprintf(buf + len, "\n");
4318 #define STAT_ATTR(si, text) \
4319 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4321 return show_stat(s, buf, si); \
4323 SLAB_ATTR_RO(text); \
4325 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4326 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4327 STAT_ATTR(FREE_FASTPATH, free_fastpath);
4328 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4329 STAT_ATTR(FREE_FROZEN, free_frozen);
4330 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4331 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4332 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4333 STAT_ATTR(ALLOC_SLAB, alloc_slab);
4334 STAT_ATTR(ALLOC_REFILL, alloc_refill);
4335 STAT_ATTR(FREE_SLAB, free_slab);
4336 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4337 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4338 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4339 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4340 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4341 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4342 STAT_ATTR(ORDER_FALLBACK, order_fallback);
4343 #endif
4345 static struct attribute *slab_attrs[] = {
4346 &slab_size_attr.attr,
4347 &object_size_attr.attr,
4348 &objs_per_slab_attr.attr,
4349 &order_attr.attr,
4350 &min_partial_attr.attr,
4351 &objects_attr.attr,
4352 &objects_partial_attr.attr,
4353 &total_objects_attr.attr,
4354 &slabs_attr.attr,
4355 &partial_attr.attr,
4356 &cpu_slabs_attr.attr,
4357 &ctor_attr.attr,
4358 &aliases_attr.attr,
4359 &align_attr.attr,
4360 &sanity_checks_attr.attr,
4361 &trace_attr.attr,
4362 &hwcache_align_attr.attr,
4363 &reclaim_account_attr.attr,
4364 &destroy_by_rcu_attr.attr,
4365 &red_zone_attr.attr,
4366 &poison_attr.attr,
4367 &store_user_attr.attr,
4368 &validate_attr.attr,
4369 &shrink_attr.attr,
4370 &alloc_calls_attr.attr,
4371 &free_calls_attr.attr,
4372 #ifdef CONFIG_ZONE_DMA
4373 &cache_dma_attr.attr,
4374 #endif
4375 #ifdef CONFIG_NUMA
4376 &remote_node_defrag_ratio_attr.attr,
4377 #endif
4378 #ifdef CONFIG_SLUB_STATS
4379 &alloc_fastpath_attr.attr,
4380 &alloc_slowpath_attr.attr,
4381 &free_fastpath_attr.attr,
4382 &free_slowpath_attr.attr,
4383 &free_frozen_attr.attr,
4384 &free_add_partial_attr.attr,
4385 &free_remove_partial_attr.attr,
4386 &alloc_from_partial_attr.attr,
4387 &alloc_slab_attr.attr,
4388 &alloc_refill_attr.attr,
4389 &free_slab_attr.attr,
4390 &cpuslab_flush_attr.attr,
4391 &deactivate_full_attr.attr,
4392 &deactivate_empty_attr.attr,
4393 &deactivate_to_head_attr.attr,
4394 &deactivate_to_tail_attr.attr,
4395 &deactivate_remote_frees_attr.attr,
4396 &order_fallback_attr.attr,
4397 #endif
4398 NULL
4401 static struct attribute_group slab_attr_group = {
4402 .attrs = slab_attrs,
4405 static ssize_t slab_attr_show(struct kobject *kobj,
4406 struct attribute *attr,
4407 char *buf)
4409 struct slab_attribute *attribute;
4410 struct kmem_cache *s;
4411 int err;
4413 attribute = to_slab_attr(attr);
4414 s = to_slab(kobj);
4416 if (!attribute->show)
4417 return -EIO;
4419 err = attribute->show(s, buf);
4421 return err;
4424 static ssize_t slab_attr_store(struct kobject *kobj,
4425 struct attribute *attr,
4426 const char *buf, size_t len)
4428 struct slab_attribute *attribute;
4429 struct kmem_cache *s;
4430 int err;
4432 attribute = to_slab_attr(attr);
4433 s = to_slab(kobj);
4435 if (!attribute->store)
4436 return -EIO;
4438 err = attribute->store(s, buf, len);
4440 return err;
4443 static void kmem_cache_release(struct kobject *kobj)
4445 struct kmem_cache *s = to_slab(kobj);
4447 kfree(s);
4450 static struct sysfs_ops slab_sysfs_ops = {
4451 .show = slab_attr_show,
4452 .store = slab_attr_store,
4455 static struct kobj_type slab_ktype = {
4456 .sysfs_ops = &slab_sysfs_ops,
4457 .release = kmem_cache_release
4460 static int uevent_filter(struct kset *kset, struct kobject *kobj)
4462 struct kobj_type *ktype = get_ktype(kobj);
4464 if (ktype == &slab_ktype)
4465 return 1;
4466 return 0;
4469 static struct kset_uevent_ops slab_uevent_ops = {
4470 .filter = uevent_filter,
4473 static struct kset *slab_kset;
4475 #define ID_STR_LENGTH 64
4477 /* Create a unique string id for a slab cache:
4479 * Format :[flags-]size
4481 static char *create_unique_id(struct kmem_cache *s)
4483 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
4484 char *p = name;
4486 BUG_ON(!name);
4488 *p++ = ':';
4490 * First flags affecting slabcache operations. We will only
4491 * get here for aliasable slabs so we do not need to support
4492 * too many flags. The flags here must cover all flags that
4493 * are matched during merging to guarantee that the id is
4494 * unique.
4496 if (s->flags & SLAB_CACHE_DMA)
4497 *p++ = 'd';
4498 if (s->flags & SLAB_RECLAIM_ACCOUNT)
4499 *p++ = 'a';
4500 if (s->flags & SLAB_DEBUG_FREE)
4501 *p++ = 'F';
4502 if (!(s->flags & SLAB_NOTRACK))
4503 *p++ = 't';
4504 if (p != name + 1)
4505 *p++ = '-';
4506 p += sprintf(p, "%07d", s->size);
4507 BUG_ON(p > name + ID_STR_LENGTH - 1);
4508 return name;
4511 static int sysfs_slab_add(struct kmem_cache *s)
4513 int err;
4514 const char *name;
4515 int unmergeable;
4517 if (slab_state < SYSFS)
4518 /* Defer until later */
4519 return 0;
4521 unmergeable = slab_unmergeable(s);
4522 if (unmergeable) {
4524 * Slabcache can never be merged so we can use the name proper.
4525 * This is typically the case for debug situations. In that
4526 * case we can catch duplicate names easily.
4528 sysfs_remove_link(&slab_kset->kobj, s->name);
4529 name = s->name;
4530 } else {
4532 * Create a unique name for the slab as a target
4533 * for the symlinks.
4535 name = create_unique_id(s);
4538 s->kobj.kset = slab_kset;
4539 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
4540 if (err) {
4541 kobject_put(&s->kobj);
4542 return err;
4545 err = sysfs_create_group(&s->kobj, &slab_attr_group);
4546 if (err)
4547 return err;
4548 kobject_uevent(&s->kobj, KOBJ_ADD);
4549 if (!unmergeable) {
4550 /* Setup first alias */
4551 sysfs_slab_alias(s, s->name);
4552 kfree(name);
4554 return 0;
4557 static void sysfs_slab_remove(struct kmem_cache *s)
4559 kobject_uevent(&s->kobj, KOBJ_REMOVE);
4560 kobject_del(&s->kobj);
4561 kobject_put(&s->kobj);
4565 * Need to buffer aliases during bootup until sysfs becomes
4566 * available lest we lose that information.
4568 struct saved_alias {
4569 struct kmem_cache *s;
4570 const char *name;
4571 struct saved_alias *next;
4574 static struct saved_alias *alias_list;
4576 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
4578 struct saved_alias *al;
4580 if (slab_state == SYSFS) {
4582 * If we have a leftover link then remove it.
4584 sysfs_remove_link(&slab_kset->kobj, name);
4585 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
4588 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
4589 if (!al)
4590 return -ENOMEM;
4592 al->s = s;
4593 al->name = name;
4594 al->next = alias_list;
4595 alias_list = al;
4596 return 0;
4599 static int __init slab_sysfs_init(void)
4601 struct kmem_cache *s;
4602 int err;
4604 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
4605 if (!slab_kset) {
4606 printk(KERN_ERR "Cannot register slab subsystem.\n");
4607 return -ENOSYS;
4610 slab_state = SYSFS;
4612 list_for_each_entry(s, &slab_caches, list) {
4613 err = sysfs_slab_add(s);
4614 if (err)
4615 printk(KERN_ERR "SLUB: Unable to add boot slab %s"
4616 " to sysfs\n", s->name);
4619 while (alias_list) {
4620 struct saved_alias *al = alias_list;
4622 alias_list = alias_list->next;
4623 err = sysfs_slab_alias(al->s, al->name);
4624 if (err)
4625 printk(KERN_ERR "SLUB: Unable to add boot slab alias"
4626 " %s to sysfs\n", s->name);
4627 kfree(al);
4630 resiliency_test();
4631 return 0;
4634 __initcall(slab_sysfs_init);
4635 #endif
4638 * The /proc/slabinfo ABI
4640 #ifdef CONFIG_SLABINFO
4641 static void print_slabinfo_header(struct seq_file *m)
4643 seq_puts(m, "slabinfo - version: 2.1\n");
4644 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
4645 "<objperslab> <pagesperslab>");
4646 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
4647 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4648 seq_putc(m, '\n');
4651 static void *s_start(struct seq_file *m, loff_t *pos)
4653 loff_t n = *pos;
4655 down_read(&slub_lock);
4656 if (!n)
4657 print_slabinfo_header(m);
4659 return seq_list_start(&slab_caches, *pos);
4662 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4664 return seq_list_next(p, &slab_caches, pos);
4667 static void s_stop(struct seq_file *m, void *p)
4669 up_read(&slub_lock);
4672 static int s_show(struct seq_file *m, void *p)
4674 unsigned long nr_partials = 0;
4675 unsigned long nr_slabs = 0;
4676 unsigned long nr_inuse = 0;
4677 unsigned long nr_objs = 0;
4678 unsigned long nr_free = 0;
4679 struct kmem_cache *s;
4680 int node;
4682 s = list_entry(p, struct kmem_cache, list);
4684 for_each_online_node(node) {
4685 struct kmem_cache_node *n = get_node(s, node);
4687 if (!n)
4688 continue;
4690 nr_partials += n->nr_partial;
4691 nr_slabs += atomic_long_read(&n->nr_slabs);
4692 nr_objs += atomic_long_read(&n->total_objects);
4693 nr_free += count_partial(n, count_free);
4696 nr_inuse = nr_objs - nr_free;
4698 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
4699 nr_objs, s->size, oo_objects(s->oo),
4700 (1 << oo_order(s->oo)));
4701 seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
4702 seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
4703 0UL);
4704 seq_putc(m, '\n');
4705 return 0;
4708 static const struct seq_operations slabinfo_op = {
4709 .start = s_start,
4710 .next = s_next,
4711 .stop = s_stop,
4712 .show = s_show,
4715 static int slabinfo_open(struct inode *inode, struct file *file)
4717 return seq_open(file, &slabinfo_op);
4720 static const struct file_operations proc_slabinfo_operations = {
4721 .open = slabinfo_open,
4722 .read = seq_read,
4723 .llseek = seq_lseek,
4724 .release = seq_release,
4727 static int __init slab_proc_init(void)
4729 proc_create("slabinfo",S_IWUSR|S_IRUGO,NULL,&proc_slabinfo_operations);
4730 return 0;
4732 module_init(slab_proc_init);
4733 #endif /* CONFIG_SLABINFO */