slub.c revision e12ba74d8ff3e2f73a583500d7095e406df4d093
1/* 2 * SLUB: A slab allocator that limits cache line use instead of queuing 3 * objects in per cpu and per node lists. 4 * 5 * The allocator synchronizes using per slab locks and only 6 * uses a centralized lock to manage a pool of partial slabs. 7 * 8 * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com> 9 */ 10 11#include <linux/mm.h> 12#include <linux/module.h> 13#include <linux/bit_spinlock.h> 14#include <linux/interrupt.h> 15#include <linux/bitops.h> 16#include <linux/slab.h> 17#include <linux/seq_file.h> 18#include <linux/cpu.h> 19#include <linux/cpuset.h> 20#include <linux/mempolicy.h> 21#include <linux/ctype.h> 22#include <linux/kallsyms.h> 23 24/* 25 * Lock order: 26 * 1. slab_lock(page) 27 * 2. slab->list_lock 28 * 29 * The slab_lock protects operations on the object of a particular 30 * slab and its metadata in the page struct. If the slab lock 31 * has been taken then no allocations nor frees can be performed 32 * on the objects in the slab nor can the slab be added or removed 33 * from the partial or full lists since this would mean modifying 34 * the page_struct of the slab. 35 * 36 * The list_lock protects the partial and full list on each node and 37 * the partial slab counter. If taken then no new slabs may be added or 38 * removed from the lists nor make the number of partial slabs be modified. 39 * (Note that the total number of slabs is an atomic value that may be 40 * modified without taking the list lock). 41 * 42 * The list_lock is a centralized lock and thus we avoid taking it as 43 * much as possible. As long as SLUB does not have to handle partial 44 * slabs, operations can continue without any centralized lock. F.e. 45 * allocating a long series of objects that fill up slabs does not require 46 * the list lock. 47 * 48 * The lock order is sometimes inverted when we are trying to get a slab 49 * off a list. We take the list_lock and then look for a page on the list 50 * to use. While we do that objects in the slabs may be freed. We can 51 * only operate on the slab if we have also taken the slab_lock. So we use 52 * a slab_trylock() on the slab. If trylock was successful then no frees 53 * can occur anymore and we can use the slab for allocations etc. If the 54 * slab_trylock() does not succeed then frees are in progress in the slab and 55 * we must stay away from it for a while since we may cause a bouncing 56 * cacheline if we try to acquire the lock. So go onto the next slab. 57 * If all pages are busy then we may allocate a new slab instead of reusing 58 * a partial slab. A new slab has noone operating on it and thus there is 59 * no danger of cacheline contention. 60 * 61 * Interrupts are disabled during allocation and deallocation in order to 62 * make the slab allocator safe to use in the context of an irq. In addition 63 * interrupts are disabled to ensure that the processor does not change 64 * while handling per_cpu slabs, due to kernel preemption. 65 * 66 * SLUB assigns one slab for allocation to each processor. 67 * Allocations only occur from these slabs called cpu slabs. 68 * 69 * Slabs with free elements are kept on a partial list and during regular 70 * operations no list for full slabs is used. If an object in a full slab is 71 * freed then the slab will show up again on the partial lists. 72 * We track full slabs for debugging purposes though because otherwise we 73 * cannot scan all objects. 74 * 75 * Slabs are freed when they become empty. Teardown and setup is 76 * minimal so we rely on the page allocators per cpu caches for 77 * fast frees and allocs. 78 * 79 * Overloading of page flags that are otherwise used for LRU management. 80 * 81 * PageActive The slab is frozen and exempt from list processing. 82 * This means that the slab is dedicated to a purpose 83 * such as satisfying allocations for a specific 84 * processor. Objects may be freed in the slab while 85 * it is frozen but slab_free will then skip the usual 86 * list operations. It is up to the processor holding 87 * the slab to integrate the slab into the slab lists 88 * when the slab is no longer needed. 89 * 90 * One use of this flag is to mark slabs that are 91 * used for allocations. Then such a slab becomes a cpu 92 * slab. The cpu slab may be equipped with an additional 93 * lockless_freelist that allows lockless access to 94 * free objects in addition to the regular freelist 95 * that requires the slab lock. 96 * 97 * PageError Slab requires special handling due to debug 98 * options set. This moves slab handling out of 99 * the fast path and disables lockless freelists. 100 */ 101 102#define FROZEN (1 << PG_active) 103 104#ifdef CONFIG_SLUB_DEBUG 105#define SLABDEBUG (1 << PG_error) 106#else 107#define SLABDEBUG 0 108#endif 109 110static inline int SlabFrozen(struct page *page) 111{ 112 return page->flags & FROZEN; 113} 114 115static inline void SetSlabFrozen(struct page *page) 116{ 117 page->flags |= FROZEN; 118} 119 120static inline void ClearSlabFrozen(struct page *page) 121{ 122 page->flags &= ~FROZEN; 123} 124 125static inline int SlabDebug(struct page *page) 126{ 127 return page->flags & SLABDEBUG; 128} 129 130static inline void SetSlabDebug(struct page *page) 131{ 132 page->flags |= SLABDEBUG; 133} 134 135static inline void ClearSlabDebug(struct page *page) 136{ 137 page->flags &= ~SLABDEBUG; 138} 139 140/* 141 * Issues still to be resolved: 142 * 143 * - The per cpu array is updated for each new slab and and is a remote 144 * cacheline for most nodes. This could become a bouncing cacheline given 145 * enough frequent updates. There are 16 pointers in a cacheline, so at 146 * max 16 cpus could compete for the cacheline which may be okay. 147 * 148 * - Support PAGE_ALLOC_DEBUG. Should be easy to do. 149 * 150 * - Variable sizing of the per node arrays 151 */ 152 153/* Enable to test recovery from slab corruption on boot */ 154#undef SLUB_RESILIENCY_TEST 155 156#if PAGE_SHIFT <= 12 157 158/* 159 * Small page size. Make sure that we do not fragment memory 160 */ 161#define DEFAULT_MAX_ORDER 1 162#define DEFAULT_MIN_OBJECTS 4 163 164#else 165 166/* 167 * Large page machines are customarily able to handle larger 168 * page orders. 169 */ 170#define DEFAULT_MAX_ORDER 2 171#define DEFAULT_MIN_OBJECTS 8 172 173#endif 174 175/* 176 * Mininum number of partial slabs. These will be left on the partial 177 * lists even if they are empty. kmem_cache_shrink may reclaim them. 178 */ 179#define MIN_PARTIAL 2 180 181/* 182 * Maximum number of desirable partial slabs. 183 * The existence of more partial slabs makes kmem_cache_shrink 184 * sort the partial list by the number of objects in the. 185 */ 186#define MAX_PARTIAL 10 187 188#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \ 189 SLAB_POISON | SLAB_STORE_USER) 190 191/* 192 * Set of flags that will prevent slab merging 193 */ 194#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 195 SLAB_TRACE | SLAB_DESTROY_BY_RCU) 196 197#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \ 198 SLAB_CACHE_DMA) 199 200#ifndef ARCH_KMALLOC_MINALIGN 201#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) 202#endif 203 204#ifndef ARCH_SLAB_MINALIGN 205#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) 206#endif 207 208/* 209 * The page->inuse field is 16 bit thus we have this limitation 210 */ 211#define MAX_OBJECTS_PER_SLAB 65535 212 213/* Internal SLUB flags */ 214#define __OBJECT_POISON 0x80000000 /* Poison object */ 215#define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */ 216 217/* Not all arches define cache_line_size */ 218#ifndef cache_line_size 219#define cache_line_size() L1_CACHE_BYTES 220#endif 221 222static int kmem_size = sizeof(struct kmem_cache); 223 224#ifdef CONFIG_SMP 225static struct notifier_block slab_notifier; 226#endif 227 228static enum { 229 DOWN, /* No slab functionality available */ 230 PARTIAL, /* kmem_cache_open() works but kmalloc does not */ 231 UP, /* Everything works but does not show up in sysfs */ 232 SYSFS /* Sysfs up */ 233} slab_state = DOWN; 234 235/* A list of all slab caches on the system */ 236static DECLARE_RWSEM(slub_lock); 237static LIST_HEAD(slab_caches); 238 239/* 240 * Tracking user of a slab. 241 */ 242struct track { 243 void *addr; /* Called from address */ 244 int cpu; /* Was running on cpu */ 245 int pid; /* Pid context */ 246 unsigned long when; /* When did the operation occur */ 247}; 248 249enum track_item { TRACK_ALLOC, TRACK_FREE }; 250 251#if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG) 252static int sysfs_slab_add(struct kmem_cache *); 253static int sysfs_slab_alias(struct kmem_cache *, const char *); 254static void sysfs_slab_remove(struct kmem_cache *); 255#else 256static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; } 257static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p) 258 { return 0; } 259static inline void sysfs_slab_remove(struct kmem_cache *s) {} 260#endif 261 262/******************************************************************** 263 * Core slab cache functions 264 *******************************************************************/ 265 266int slab_is_available(void) 267{ 268 return slab_state >= UP; 269} 270 271static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) 272{ 273#ifdef CONFIG_NUMA 274 return s->node[node]; 275#else 276 return &s->local_node; 277#endif 278} 279 280static inline int check_valid_pointer(struct kmem_cache *s, 281 struct page *page, const void *object) 282{ 283 void *base; 284 285 if (!object) 286 return 1; 287 288 base = page_address(page); 289 if (object < base || object >= base + s->objects * s->size || 290 (object - base) % s->size) { 291 return 0; 292 } 293 294 return 1; 295} 296 297/* 298 * Slow version of get and set free pointer. 299 * 300 * This version requires touching the cache lines of kmem_cache which 301 * we avoid to do in the fast alloc free paths. There we obtain the offset 302 * from the page struct. 303 */ 304static inline void *get_freepointer(struct kmem_cache *s, void *object) 305{ 306 return *(void **)(object + s->offset); 307} 308 309static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) 310{ 311 *(void **)(object + s->offset) = fp; 312} 313 314/* Loop over all objects in a slab */ 315#define for_each_object(__p, __s, __addr) \ 316 for (__p = (__addr); __p < (__addr) + (__s)->objects * (__s)->size;\ 317 __p += (__s)->size) 318 319/* Scan freelist */ 320#define for_each_free_object(__p, __s, __free) \ 321 for (__p = (__free); __p; __p = get_freepointer((__s), __p)) 322 323/* Determine object index from a given position */ 324static inline int slab_index(void *p, struct kmem_cache *s, void *addr) 325{ 326 return (p - addr) / s->size; 327} 328 329#ifdef CONFIG_SLUB_DEBUG 330/* 331 * Debug settings: 332 */ 333#ifdef CONFIG_SLUB_DEBUG_ON 334static int slub_debug = DEBUG_DEFAULT_FLAGS; 335#else 336static int slub_debug; 337#endif 338 339static char *slub_debug_slabs; 340 341/* 342 * Object debugging 343 */ 344static void print_section(char *text, u8 *addr, unsigned int length) 345{ 346 int i, offset; 347 int newline = 1; 348 char ascii[17]; 349 350 ascii[16] = 0; 351 352 for (i = 0; i < length; i++) { 353 if (newline) { 354 printk(KERN_ERR "%8s 0x%p: ", text, addr + i); 355 newline = 0; 356 } 357 printk(" %02x", addr[i]); 358 offset = i % 16; 359 ascii[offset] = isgraph(addr[i]) ? addr[i] : '.'; 360 if (offset == 15) { 361 printk(" %s\n",ascii); 362 newline = 1; 363 } 364 } 365 if (!newline) { 366 i %= 16; 367 while (i < 16) { 368 printk(" "); 369 ascii[i] = ' '; 370 i++; 371 } 372 printk(" %s\n", ascii); 373 } 374} 375 376static struct track *get_track(struct kmem_cache *s, void *object, 377 enum track_item alloc) 378{ 379 struct track *p; 380 381 if (s->offset) 382 p = object + s->offset + sizeof(void *); 383 else 384 p = object + s->inuse; 385 386 return p + alloc; 387} 388 389static void set_track(struct kmem_cache *s, void *object, 390 enum track_item alloc, void *addr) 391{ 392 struct track *p; 393 394 if (s->offset) 395 p = object + s->offset + sizeof(void *); 396 else 397 p = object + s->inuse; 398 399 p += alloc; 400 if (addr) { 401 p->addr = addr; 402 p->cpu = smp_processor_id(); 403 p->pid = current ? current->pid : -1; 404 p->when = jiffies; 405 } else 406 memset(p, 0, sizeof(struct track)); 407} 408 409static void init_tracking(struct kmem_cache *s, void *object) 410{ 411 if (!(s->flags & SLAB_STORE_USER)) 412 return; 413 414 set_track(s, object, TRACK_FREE, NULL); 415 set_track(s, object, TRACK_ALLOC, NULL); 416} 417 418static void print_track(const char *s, struct track *t) 419{ 420 if (!t->addr) 421 return; 422 423 printk(KERN_ERR "INFO: %s in ", s); 424 __print_symbol("%s", (unsigned long)t->addr); 425 printk(" age=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid); 426} 427 428static void print_tracking(struct kmem_cache *s, void *object) 429{ 430 if (!(s->flags & SLAB_STORE_USER)) 431 return; 432 433 print_track("Allocated", get_track(s, object, TRACK_ALLOC)); 434 print_track("Freed", get_track(s, object, TRACK_FREE)); 435} 436 437static void print_page_info(struct page *page) 438{ 439 printk(KERN_ERR "INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n", 440 page, page->inuse, page->freelist, page->flags); 441 442} 443 444static void slab_bug(struct kmem_cache *s, char *fmt, ...) 445{ 446 va_list args; 447 char buf[100]; 448 449 va_start(args, fmt); 450 vsnprintf(buf, sizeof(buf), fmt, args); 451 va_end(args); 452 printk(KERN_ERR "========================================" 453 "=====================================\n"); 454 printk(KERN_ERR "BUG %s: %s\n", s->name, buf); 455 printk(KERN_ERR "----------------------------------------" 456 "-------------------------------------\n\n"); 457} 458 459static void slab_fix(struct kmem_cache *s, char *fmt, ...) 460{ 461 va_list args; 462 char buf[100]; 463 464 va_start(args, fmt); 465 vsnprintf(buf, sizeof(buf), fmt, args); 466 va_end(args); 467 printk(KERN_ERR "FIX %s: %s\n", s->name, buf); 468} 469 470static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) 471{ 472 unsigned int off; /* Offset of last byte */ 473 u8 *addr = page_address(page); 474 475 print_tracking(s, p); 476 477 print_page_info(page); 478 479 printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n", 480 p, p - addr, get_freepointer(s, p)); 481 482 if (p > addr + 16) 483 print_section("Bytes b4", p - 16, 16); 484 485 print_section("Object", p, min(s->objsize, 128)); 486 487 if (s->flags & SLAB_RED_ZONE) 488 print_section("Redzone", p + s->objsize, 489 s->inuse - s->objsize); 490 491 if (s->offset) 492 off = s->offset + sizeof(void *); 493 else 494 off = s->inuse; 495 496 if (s->flags & SLAB_STORE_USER) 497 off += 2 * sizeof(struct track); 498 499 if (off != s->size) 500 /* Beginning of the filler is the free pointer */ 501 print_section("Padding", p + off, s->size - off); 502 503 dump_stack(); 504} 505 506static void object_err(struct kmem_cache *s, struct page *page, 507 u8 *object, char *reason) 508{ 509 slab_bug(s, reason); 510 print_trailer(s, page, object); 511} 512 513static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...) 514{ 515 va_list args; 516 char buf[100]; 517 518 va_start(args, fmt); 519 vsnprintf(buf, sizeof(buf), fmt, args); 520 va_end(args); 521 slab_bug(s, fmt); 522 print_page_info(page); 523 dump_stack(); 524} 525 526static void init_object(struct kmem_cache *s, void *object, int active) 527{ 528 u8 *p = object; 529 530 if (s->flags & __OBJECT_POISON) { 531 memset(p, POISON_FREE, s->objsize - 1); 532 p[s->objsize -1] = POISON_END; 533 } 534 535 if (s->flags & SLAB_RED_ZONE) 536 memset(p + s->objsize, 537 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE, 538 s->inuse - s->objsize); 539} 540 541static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes) 542{ 543 while (bytes) { 544 if (*start != (u8)value) 545 return start; 546 start++; 547 bytes--; 548 } 549 return NULL; 550} 551 552static void restore_bytes(struct kmem_cache *s, char *message, u8 data, 553 void *from, void *to) 554{ 555 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data); 556 memset(from, data, to - from); 557} 558 559static int check_bytes_and_report(struct kmem_cache *s, struct page *page, 560 u8 *object, char *what, 561 u8* start, unsigned int value, unsigned int bytes) 562{ 563 u8 *fault; 564 u8 *end; 565 566 fault = check_bytes(start, value, bytes); 567 if (!fault) 568 return 1; 569 570 end = start + bytes; 571 while (end > fault && end[-1] == value) 572 end--; 573 574 slab_bug(s, "%s overwritten", what); 575 printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n", 576 fault, end - 1, fault[0], value); 577 print_trailer(s, page, object); 578 579 restore_bytes(s, what, value, fault, end); 580 return 0; 581} 582 583/* 584 * Object layout: 585 * 586 * object address 587 * Bytes of the object to be managed. 588 * If the freepointer may overlay the object then the free 589 * pointer is the first word of the object. 590 * 591 * Poisoning uses 0x6b (POISON_FREE) and the last byte is 592 * 0xa5 (POISON_END) 593 * 594 * object + s->objsize 595 * Padding to reach word boundary. This is also used for Redzoning. 596 * Padding is extended by another word if Redzoning is enabled and 597 * objsize == inuse. 598 * 599 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with 600 * 0xcc (RED_ACTIVE) for objects in use. 601 * 602 * object + s->inuse 603 * Meta data starts here. 604 * 605 * A. Free pointer (if we cannot overwrite object on free) 606 * B. Tracking data for SLAB_STORE_USER 607 * C. Padding to reach required alignment boundary or at mininum 608 * one word if debuggin is on to be able to detect writes 609 * before the word boundary. 610 * 611 * Padding is done using 0x5a (POISON_INUSE) 612 * 613 * object + s->size 614 * Nothing is used beyond s->size. 615 * 616 * If slabcaches are merged then the objsize and inuse boundaries are mostly 617 * ignored. And therefore no slab options that rely on these boundaries 618 * may be used with merged slabcaches. 619 */ 620 621static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) 622{ 623 unsigned long off = s->inuse; /* The end of info */ 624 625 if (s->offset) 626 /* Freepointer is placed after the object. */ 627 off += sizeof(void *); 628 629 if (s->flags & SLAB_STORE_USER) 630 /* We also have user information there */ 631 off += 2 * sizeof(struct track); 632 633 if (s->size == off) 634 return 1; 635 636 return check_bytes_and_report(s, page, p, "Object padding", 637 p + off, POISON_INUSE, s->size - off); 638} 639 640static int slab_pad_check(struct kmem_cache *s, struct page *page) 641{ 642 u8 *start; 643 u8 *fault; 644 u8 *end; 645 int length; 646 int remainder; 647 648 if (!(s->flags & SLAB_POISON)) 649 return 1; 650 651 start = page_address(page); 652 end = start + (PAGE_SIZE << s->order); 653 length = s->objects * s->size; 654 remainder = end - (start + length); 655 if (!remainder) 656 return 1; 657 658 fault = check_bytes(start + length, POISON_INUSE, remainder); 659 if (!fault) 660 return 1; 661 while (end > fault && end[-1] == POISON_INUSE) 662 end--; 663 664 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1); 665 print_section("Padding", start, length); 666 667 restore_bytes(s, "slab padding", POISON_INUSE, start, end); 668 return 0; 669} 670 671static int check_object(struct kmem_cache *s, struct page *page, 672 void *object, int active) 673{ 674 u8 *p = object; 675 u8 *endobject = object + s->objsize; 676 677 if (s->flags & SLAB_RED_ZONE) { 678 unsigned int red = 679 active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE; 680 681 if (!check_bytes_and_report(s, page, object, "Redzone", 682 endobject, red, s->inuse - s->objsize)) 683 return 0; 684 } else { 685 if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) 686 check_bytes_and_report(s, page, p, "Alignment padding", endobject, 687 POISON_INUSE, s->inuse - s->objsize); 688 } 689 690 if (s->flags & SLAB_POISON) { 691 if (!active && (s->flags & __OBJECT_POISON) && 692 (!check_bytes_and_report(s, page, p, "Poison", p, 693 POISON_FREE, s->objsize - 1) || 694 !check_bytes_and_report(s, page, p, "Poison", 695 p + s->objsize -1, POISON_END, 1))) 696 return 0; 697 /* 698 * check_pad_bytes cleans up on its own. 699 */ 700 check_pad_bytes(s, page, p); 701 } 702 703 if (!s->offset && active) 704 /* 705 * Object and freepointer overlap. Cannot check 706 * freepointer while object is allocated. 707 */ 708 return 1; 709 710 /* Check free pointer validity */ 711 if (!check_valid_pointer(s, page, get_freepointer(s, p))) { 712 object_err(s, page, p, "Freepointer corrupt"); 713 /* 714 * No choice but to zap it and thus loose the remainder 715 * of the free objects in this slab. May cause 716 * another error because the object count is now wrong. 717 */ 718 set_freepointer(s, p, NULL); 719 return 0; 720 } 721 return 1; 722} 723 724static int check_slab(struct kmem_cache *s, struct page *page) 725{ 726 VM_BUG_ON(!irqs_disabled()); 727 728 if (!PageSlab(page)) { 729 slab_err(s, page, "Not a valid slab page"); 730 return 0; 731 } 732 if (page->offset * sizeof(void *) != s->offset) { 733 slab_err(s, page, "Corrupted offset %lu", 734 (unsigned long)(page->offset * sizeof(void *))); 735 return 0; 736 } 737 if (page->inuse > s->objects) { 738 slab_err(s, page, "inuse %u > max %u", 739 s->name, page->inuse, s->objects); 740 return 0; 741 } 742 /* Slab_pad_check fixes things up after itself */ 743 slab_pad_check(s, page); 744 return 1; 745} 746 747/* 748 * Determine if a certain object on a page is on the freelist. Must hold the 749 * slab lock to guarantee that the chains are in a consistent state. 750 */ 751static int on_freelist(struct kmem_cache *s, struct page *page, void *search) 752{ 753 int nr = 0; 754 void *fp = page->freelist; 755 void *object = NULL; 756 757 while (fp && nr <= s->objects) { 758 if (fp == search) 759 return 1; 760 if (!check_valid_pointer(s, page, fp)) { 761 if (object) { 762 object_err(s, page, object, 763 "Freechain corrupt"); 764 set_freepointer(s, object, NULL); 765 break; 766 } else { 767 slab_err(s, page, "Freepointer corrupt"); 768 page->freelist = NULL; 769 page->inuse = s->objects; 770 slab_fix(s, "Freelist cleared"); 771 return 0; 772 } 773 break; 774 } 775 object = fp; 776 fp = get_freepointer(s, object); 777 nr++; 778 } 779 780 if (page->inuse != s->objects - nr) { 781 slab_err(s, page, "Wrong object count. Counter is %d but " 782 "counted were %d", page->inuse, s->objects - nr); 783 page->inuse = s->objects - nr; 784 slab_fix(s, "Object count adjusted."); 785 } 786 return search == NULL; 787} 788 789static void trace(struct kmem_cache *s, struct page *page, void *object, int alloc) 790{ 791 if (s->flags & SLAB_TRACE) { 792 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n", 793 s->name, 794 alloc ? "alloc" : "free", 795 object, page->inuse, 796 page->freelist); 797 798 if (!alloc) 799 print_section("Object", (void *)object, s->objsize); 800 801 dump_stack(); 802 } 803} 804 805/* 806 * Tracking of fully allocated slabs for debugging purposes. 807 */ 808static void add_full(struct kmem_cache_node *n, struct page *page) 809{ 810 spin_lock(&n->list_lock); 811 list_add(&page->lru, &n->full); 812 spin_unlock(&n->list_lock); 813} 814 815static void remove_full(struct kmem_cache *s, struct page *page) 816{ 817 struct kmem_cache_node *n; 818 819 if (!(s->flags & SLAB_STORE_USER)) 820 return; 821 822 n = get_node(s, page_to_nid(page)); 823 824 spin_lock(&n->list_lock); 825 list_del(&page->lru); 826 spin_unlock(&n->list_lock); 827} 828 829static void setup_object_debug(struct kmem_cache *s, struct page *page, 830 void *object) 831{ 832 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))) 833 return; 834 835 init_object(s, object, 0); 836 init_tracking(s, object); 837} 838 839static int alloc_debug_processing(struct kmem_cache *s, struct page *page, 840 void *object, void *addr) 841{ 842 if (!check_slab(s, page)) 843 goto bad; 844 845 if (object && !on_freelist(s, page, object)) { 846 object_err(s, page, object, "Object already allocated"); 847 goto bad; 848 } 849 850 if (!check_valid_pointer(s, page, object)) { 851 object_err(s, page, object, "Freelist Pointer check fails"); 852 goto bad; 853 } 854 855 if (object && !check_object(s, page, object, 0)) 856 goto bad; 857 858 /* Success perform special debug activities for allocs */ 859 if (s->flags & SLAB_STORE_USER) 860 set_track(s, object, TRACK_ALLOC, addr); 861 trace(s, page, object, 1); 862 init_object(s, object, 1); 863 return 1; 864 865bad: 866 if (PageSlab(page)) { 867 /* 868 * If this is a slab page then lets do the best we can 869 * to avoid issues in the future. Marking all objects 870 * as used avoids touching the remaining objects. 871 */ 872 slab_fix(s, "Marking all objects used"); 873 page->inuse = s->objects; 874 page->freelist = NULL; 875 /* Fix up fields that may be corrupted */ 876 page->offset = s->offset / sizeof(void *); 877 } 878 return 0; 879} 880 881static int free_debug_processing(struct kmem_cache *s, struct page *page, 882 void *object, void *addr) 883{ 884 if (!check_slab(s, page)) 885 goto fail; 886 887 if (!check_valid_pointer(s, page, object)) { 888 slab_err(s, page, "Invalid object pointer 0x%p", object); 889 goto fail; 890 } 891 892 if (on_freelist(s, page, object)) { 893 object_err(s, page, object, "Object already free"); 894 goto fail; 895 } 896 897 if (!check_object(s, page, object, 1)) 898 return 0; 899 900 if (unlikely(s != page->slab)) { 901 if (!PageSlab(page)) 902 slab_err(s, page, "Attempt to free object(0x%p) " 903 "outside of slab", object); 904 else 905 if (!page->slab) { 906 printk(KERN_ERR 907 "SLUB <none>: no slab for object 0x%p.\n", 908 object); 909 dump_stack(); 910 } 911 else 912 object_err(s, page, object, 913 "page slab pointer corrupt."); 914 goto fail; 915 } 916 917 /* Special debug activities for freeing objects */ 918 if (!SlabFrozen(page) && !page->freelist) 919 remove_full(s, page); 920 if (s->flags & SLAB_STORE_USER) 921 set_track(s, object, TRACK_FREE, addr); 922 trace(s, page, object, 0); 923 init_object(s, object, 0); 924 return 1; 925 926fail: 927 slab_fix(s, "Object at 0x%p not freed", object); 928 return 0; 929} 930 931static int __init setup_slub_debug(char *str) 932{ 933 slub_debug = DEBUG_DEFAULT_FLAGS; 934 if (*str++ != '=' || !*str) 935 /* 936 * No options specified. Switch on full debugging. 937 */ 938 goto out; 939 940 if (*str == ',') 941 /* 942 * No options but restriction on slabs. This means full 943 * debugging for slabs matching a pattern. 944 */ 945 goto check_slabs; 946 947 slub_debug = 0; 948 if (*str == '-') 949 /* 950 * Switch off all debugging measures. 951 */ 952 goto out; 953 954 /* 955 * Determine which debug features should be switched on 956 */ 957 for ( ;*str && *str != ','; str++) { 958 switch (tolower(*str)) { 959 case 'f': 960 slub_debug |= SLAB_DEBUG_FREE; 961 break; 962 case 'z': 963 slub_debug |= SLAB_RED_ZONE; 964 break; 965 case 'p': 966 slub_debug |= SLAB_POISON; 967 break; 968 case 'u': 969 slub_debug |= SLAB_STORE_USER; 970 break; 971 case 't': 972 slub_debug |= SLAB_TRACE; 973 break; 974 default: 975 printk(KERN_ERR "slub_debug option '%c' " 976 "unknown. skipped\n",*str); 977 } 978 } 979 980check_slabs: 981 if (*str == ',') 982 slub_debug_slabs = str + 1; 983out: 984 return 1; 985} 986 987__setup("slub_debug", setup_slub_debug); 988 989static unsigned long kmem_cache_flags(unsigned long objsize, 990 unsigned long flags, const char *name, 991 void (*ctor)(void *, struct kmem_cache *, unsigned long)) 992{ 993 /* 994 * The page->offset field is only 16 bit wide. This is an offset 995 * in units of words from the beginning of an object. If the slab 996 * size is bigger then we cannot move the free pointer behind the 997 * object anymore. 998 * 999 * On 32 bit platforms the limit is 256k. On 64bit platforms 1000 * the limit is 512k. 1001 * 1002 * Debugging or ctor may create a need to move the free 1003 * pointer. Fail if this happens. 1004 */ 1005 if (objsize >= 65535 * sizeof(void *)) { 1006 BUG_ON(flags & (SLAB_RED_ZONE | SLAB_POISON | 1007 SLAB_STORE_USER | SLAB_DESTROY_BY_RCU)); 1008 BUG_ON(ctor); 1009 } else { 1010 /* 1011 * Enable debugging if selected on the kernel commandline. 1012 */ 1013 if (slub_debug && (!slub_debug_slabs || 1014 strncmp(slub_debug_slabs, name, 1015 strlen(slub_debug_slabs)) == 0)) 1016 flags |= slub_debug; 1017 } 1018 1019 return flags; 1020} 1021#else 1022static inline void setup_object_debug(struct kmem_cache *s, 1023 struct page *page, void *object) {} 1024 1025static inline int alloc_debug_processing(struct kmem_cache *s, 1026 struct page *page, void *object, void *addr) { return 0; } 1027 1028static inline int free_debug_processing(struct kmem_cache *s, 1029 struct page *page, void *object, void *addr) { return 0; } 1030 1031static inline int slab_pad_check(struct kmem_cache *s, struct page *page) 1032 { return 1; } 1033static inline int check_object(struct kmem_cache *s, struct page *page, 1034 void *object, int active) { return 1; } 1035static inline void add_full(struct kmem_cache_node *n, struct page *page) {} 1036static inline unsigned long kmem_cache_flags(unsigned long objsize, 1037 unsigned long flags, const char *name, 1038 void (*ctor)(void *, struct kmem_cache *, unsigned long)) 1039{ 1040 return flags; 1041} 1042#define slub_debug 0 1043#endif 1044/* 1045 * Slab allocation and freeing 1046 */ 1047static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) 1048{ 1049 struct page * page; 1050 int pages = 1 << s->order; 1051 1052 if (s->order) 1053 flags |= __GFP_COMP; 1054 1055 if (s->flags & SLAB_CACHE_DMA) 1056 flags |= SLUB_DMA; 1057 1058 if (s->flags & SLAB_RECLAIM_ACCOUNT) 1059 flags |= __GFP_RECLAIMABLE; 1060 1061 if (node == -1) 1062 page = alloc_pages(flags, s->order); 1063 else 1064 page = alloc_pages_node(node, flags, s->order); 1065 1066 if (!page) 1067 return NULL; 1068 1069 mod_zone_page_state(page_zone(page), 1070 (s->flags & SLAB_RECLAIM_ACCOUNT) ? 1071 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, 1072 pages); 1073 1074 return page; 1075} 1076 1077static void setup_object(struct kmem_cache *s, struct page *page, 1078 void *object) 1079{ 1080 setup_object_debug(s, page, object); 1081 if (unlikely(s->ctor)) 1082 s->ctor(object, s, 0); 1083} 1084 1085static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) 1086{ 1087 struct page *page; 1088 struct kmem_cache_node *n; 1089 void *start; 1090 void *end; 1091 void *last; 1092 void *p; 1093 1094 BUG_ON(flags & GFP_SLAB_BUG_MASK); 1095 1096 if (flags & __GFP_WAIT) 1097 local_irq_enable(); 1098 1099 page = allocate_slab(s, 1100 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); 1101 if (!page) 1102 goto out; 1103 1104 n = get_node(s, page_to_nid(page)); 1105 if (n) 1106 atomic_long_inc(&n->nr_slabs); 1107 page->offset = s->offset / sizeof(void *); 1108 page->slab = s; 1109 page->flags |= 1 << PG_slab; 1110 if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON | 1111 SLAB_STORE_USER | SLAB_TRACE)) 1112 SetSlabDebug(page); 1113 1114 start = page_address(page); 1115 end = start + s->objects * s->size; 1116 1117 if (unlikely(s->flags & SLAB_POISON)) 1118 memset(start, POISON_INUSE, PAGE_SIZE << s->order); 1119 1120 last = start; 1121 for_each_object(p, s, start) { 1122 setup_object(s, page, last); 1123 set_freepointer(s, last, p); 1124 last = p; 1125 } 1126 setup_object(s, page, last); 1127 set_freepointer(s, last, NULL); 1128 1129 page->freelist = start; 1130 page->lockless_freelist = NULL; 1131 page->inuse = 0; 1132out: 1133 if (flags & __GFP_WAIT) 1134 local_irq_disable(); 1135 return page; 1136} 1137 1138static void __free_slab(struct kmem_cache *s, struct page *page) 1139{ 1140 int pages = 1 << s->order; 1141 1142 if (unlikely(SlabDebug(page))) { 1143 void *p; 1144 1145 slab_pad_check(s, page); 1146 for_each_object(p, s, page_address(page)) 1147 check_object(s, page, p, 0); 1148 ClearSlabDebug(page); 1149 } 1150 1151 mod_zone_page_state(page_zone(page), 1152 (s->flags & SLAB_RECLAIM_ACCOUNT) ? 1153 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, 1154 - pages); 1155 1156 page->mapping = NULL; 1157 __free_pages(page, s->order); 1158} 1159 1160static void rcu_free_slab(struct rcu_head *h) 1161{ 1162 struct page *page; 1163 1164 page = container_of((struct list_head *)h, struct page, lru); 1165 __free_slab(page->slab, page); 1166} 1167 1168static void free_slab(struct kmem_cache *s, struct page *page) 1169{ 1170 if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) { 1171 /* 1172 * RCU free overloads the RCU head over the LRU 1173 */ 1174 struct rcu_head *head = (void *)&page->lru; 1175 1176 call_rcu(head, rcu_free_slab); 1177 } else 1178 __free_slab(s, page); 1179} 1180 1181static void discard_slab(struct kmem_cache *s, struct page *page) 1182{ 1183 struct kmem_cache_node *n = get_node(s, page_to_nid(page)); 1184 1185 atomic_long_dec(&n->nr_slabs); 1186 reset_page_mapcount(page); 1187 __ClearPageSlab(page); 1188 free_slab(s, page); 1189} 1190 1191/* 1192 * Per slab locking using the pagelock 1193 */ 1194static __always_inline void slab_lock(struct page *page) 1195{ 1196 bit_spin_lock(PG_locked, &page->flags); 1197} 1198 1199static __always_inline void slab_unlock(struct page *page) 1200{ 1201 bit_spin_unlock(PG_locked, &page->flags); 1202} 1203 1204static __always_inline int slab_trylock(struct page *page) 1205{ 1206 int rc = 1; 1207 1208 rc = bit_spin_trylock(PG_locked, &page->flags); 1209 return rc; 1210} 1211 1212/* 1213 * Management of partially allocated slabs 1214 */ 1215static void add_partial_tail(struct kmem_cache_node *n, struct page *page) 1216{ 1217 spin_lock(&n->list_lock); 1218 n->nr_partial++; 1219 list_add_tail(&page->lru, &n->partial); 1220 spin_unlock(&n->list_lock); 1221} 1222 1223static void add_partial(struct kmem_cache_node *n, struct page *page) 1224{ 1225 spin_lock(&n->list_lock); 1226 n->nr_partial++; 1227 list_add(&page->lru, &n->partial); 1228 spin_unlock(&n->list_lock); 1229} 1230 1231static void remove_partial(struct kmem_cache *s, 1232 struct page *page) 1233{ 1234 struct kmem_cache_node *n = get_node(s, page_to_nid(page)); 1235 1236 spin_lock(&n->list_lock); 1237 list_del(&page->lru); 1238 n->nr_partial--; 1239 spin_unlock(&n->list_lock); 1240} 1241 1242/* 1243 * Lock slab and remove from the partial list. 1244 * 1245 * Must hold list_lock. 1246 */ 1247static inline int lock_and_freeze_slab(struct kmem_cache_node *n, struct page *page) 1248{ 1249 if (slab_trylock(page)) { 1250 list_del(&page->lru); 1251 n->nr_partial--; 1252 SetSlabFrozen(page); 1253 return 1; 1254 } 1255 return 0; 1256} 1257 1258/* 1259 * Try to allocate a partial slab from a specific node. 1260 */ 1261static struct page *get_partial_node(struct kmem_cache_node *n) 1262{ 1263 struct page *page; 1264 1265 /* 1266 * Racy check. If we mistakenly see no partial slabs then we 1267 * just allocate an empty slab. If we mistakenly try to get a 1268 * partial slab and there is none available then get_partials() 1269 * will return NULL. 1270 */ 1271 if (!n || !n->nr_partial) 1272 return NULL; 1273 1274 spin_lock(&n->list_lock); 1275 list_for_each_entry(page, &n->partial, lru) 1276 if (lock_and_freeze_slab(n, page)) 1277 goto out; 1278 page = NULL; 1279out: 1280 spin_unlock(&n->list_lock); 1281 return page; 1282} 1283 1284/* 1285 * Get a page from somewhere. Search in increasing NUMA distances. 1286 */ 1287static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags) 1288{ 1289#ifdef CONFIG_NUMA 1290 struct zonelist *zonelist; 1291 struct zone **z; 1292 struct page *page; 1293 1294 /* 1295 * The defrag ratio allows a configuration of the tradeoffs between 1296 * inter node defragmentation and node local allocations. A lower 1297 * defrag_ratio increases the tendency to do local allocations 1298 * instead of attempting to obtain partial slabs from other nodes. 1299 * 1300 * If the defrag_ratio is set to 0 then kmalloc() always 1301 * returns node local objects. If the ratio is higher then kmalloc() 1302 * may return off node objects because partial slabs are obtained 1303 * from other nodes and filled up. 1304 * 1305 * If /sys/slab/xx/defrag_ratio is set to 100 (which makes 1306 * defrag_ratio = 1000) then every (well almost) allocation will 1307 * first attempt to defrag slab caches on other nodes. This means 1308 * scanning over all nodes to look for partial slabs which may be 1309 * expensive if we do it every time we are trying to find a slab 1310 * with available objects. 1311 */ 1312 if (!s->defrag_ratio || get_cycles() % 1024 > s->defrag_ratio) 1313 return NULL; 1314 1315 zonelist = &NODE_DATA(slab_node(current->mempolicy)) 1316 ->node_zonelists[gfp_zone(flags)]; 1317 for (z = zonelist->zones; *z; z++) { 1318 struct kmem_cache_node *n; 1319 1320 n = get_node(s, zone_to_nid(*z)); 1321 1322 if (n && cpuset_zone_allowed_hardwall(*z, flags) && 1323 n->nr_partial > MIN_PARTIAL) { 1324 page = get_partial_node(n); 1325 if (page) 1326 return page; 1327 } 1328 } 1329#endif 1330 return NULL; 1331} 1332 1333/* 1334 * Get a partial page, lock it and return it. 1335 */ 1336static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node) 1337{ 1338 struct page *page; 1339 int searchnode = (node == -1) ? numa_node_id() : node; 1340 1341 page = get_partial_node(get_node(s, searchnode)); 1342 if (page || (flags & __GFP_THISNODE)) 1343 return page; 1344 1345 return get_any_partial(s, flags); 1346} 1347 1348/* 1349 * Move a page back to the lists. 1350 * 1351 * Must be called with the slab lock held. 1352 * 1353 * On exit the slab lock will have been dropped. 1354 */ 1355static void unfreeze_slab(struct kmem_cache *s, struct page *page) 1356{ 1357 struct kmem_cache_node *n = get_node(s, page_to_nid(page)); 1358 1359 ClearSlabFrozen(page); 1360 if (page->inuse) { 1361 1362 if (page->freelist) 1363 add_partial(n, page); 1364 else if (SlabDebug(page) && (s->flags & SLAB_STORE_USER)) 1365 add_full(n, page); 1366 slab_unlock(page); 1367 1368 } else { 1369 if (n->nr_partial < MIN_PARTIAL) { 1370 /* 1371 * Adding an empty slab to the partial slabs in order 1372 * to avoid page allocator overhead. This slab needs 1373 * to come after the other slabs with objects in 1374 * order to fill them up. That way the size of the 1375 * partial list stays small. kmem_cache_shrink can 1376 * reclaim empty slabs from the partial list. 1377 */ 1378 add_partial_tail(n, page); 1379 slab_unlock(page); 1380 } else { 1381 slab_unlock(page); 1382 discard_slab(s, page); 1383 } 1384 } 1385} 1386 1387/* 1388 * Remove the cpu slab 1389 */ 1390static void deactivate_slab(struct kmem_cache *s, struct page *page, int cpu) 1391{ 1392 /* 1393 * Merge cpu freelist into freelist. Typically we get here 1394 * because both freelists are empty. So this is unlikely 1395 * to occur. 1396 */ 1397 while (unlikely(page->lockless_freelist)) { 1398 void **object; 1399 1400 /* Retrieve object from cpu_freelist */ 1401 object = page->lockless_freelist; 1402 page->lockless_freelist = page->lockless_freelist[page->offset]; 1403 1404 /* And put onto the regular freelist */ 1405 object[page->offset] = page->freelist; 1406 page->freelist = object; 1407 page->inuse--; 1408 } 1409 s->cpu_slab[cpu] = NULL; 1410 unfreeze_slab(s, page); 1411} 1412 1413static inline void flush_slab(struct kmem_cache *s, struct page *page, int cpu) 1414{ 1415 slab_lock(page); 1416 deactivate_slab(s, page, cpu); 1417} 1418 1419/* 1420 * Flush cpu slab. 1421 * Called from IPI handler with interrupts disabled. 1422 */ 1423static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) 1424{ 1425 struct page *page = s->cpu_slab[cpu]; 1426 1427 if (likely(page)) 1428 flush_slab(s, page, cpu); 1429} 1430 1431static void flush_cpu_slab(void *d) 1432{ 1433 struct kmem_cache *s = d; 1434 int cpu = smp_processor_id(); 1435 1436 __flush_cpu_slab(s, cpu); 1437} 1438 1439static void flush_all(struct kmem_cache *s) 1440{ 1441#ifdef CONFIG_SMP 1442 on_each_cpu(flush_cpu_slab, s, 1, 1); 1443#else 1444 unsigned long flags; 1445 1446 local_irq_save(flags); 1447 flush_cpu_slab(s); 1448 local_irq_restore(flags); 1449#endif 1450} 1451 1452/* 1453 * Slow path. The lockless freelist is empty or we need to perform 1454 * debugging duties. 1455 * 1456 * Interrupts are disabled. 1457 * 1458 * Processing is still very fast if new objects have been freed to the 1459 * regular freelist. In that case we simply take over the regular freelist 1460 * as the lockless freelist and zap the regular freelist. 1461 * 1462 * If that is not working then we fall back to the partial lists. We take the 1463 * first element of the freelist as the object to allocate now and move the 1464 * rest of the freelist to the lockless freelist. 1465 * 1466 * And if we were unable to get a new slab from the partial slab lists then 1467 * we need to allocate a new slab. This is slowest path since we may sleep. 1468 */ 1469static void *__slab_alloc(struct kmem_cache *s, 1470 gfp_t gfpflags, int node, void *addr, struct page *page) 1471{ 1472 void **object; 1473 int cpu = smp_processor_id(); 1474 1475 if (!page) 1476 goto new_slab; 1477 1478 slab_lock(page); 1479 if (unlikely(node != -1 && page_to_nid(page) != node)) 1480 goto another_slab; 1481load_freelist: 1482 object = page->freelist; 1483 if (unlikely(!object)) 1484 goto another_slab; 1485 if (unlikely(SlabDebug(page))) 1486 goto debug; 1487 1488 object = page->freelist; 1489 page->lockless_freelist = object[page->offset]; 1490 page->inuse = s->objects; 1491 page->freelist = NULL; 1492 slab_unlock(page); 1493 return object; 1494 1495another_slab: 1496 deactivate_slab(s, page, cpu); 1497 1498new_slab: 1499 page = get_partial(s, gfpflags, node); 1500 if (page) { 1501 s->cpu_slab[cpu] = page; 1502 goto load_freelist; 1503 } 1504 1505 page = new_slab(s, gfpflags, node); 1506 if (page) { 1507 cpu = smp_processor_id(); 1508 if (s->cpu_slab[cpu]) { 1509 /* 1510 * Someone else populated the cpu_slab while we 1511 * enabled interrupts, or we have gotten scheduled 1512 * on another cpu. The page may not be on the 1513 * requested node even if __GFP_THISNODE was 1514 * specified. So we need to recheck. 1515 */ 1516 if (node == -1 || 1517 page_to_nid(s->cpu_slab[cpu]) == node) { 1518 /* 1519 * Current cpuslab is acceptable and we 1520 * want the current one since its cache hot 1521 */ 1522 discard_slab(s, page); 1523 page = s->cpu_slab[cpu]; 1524 slab_lock(page); 1525 goto load_freelist; 1526 } 1527 /* New slab does not fit our expectations */ 1528 flush_slab(s, s->cpu_slab[cpu], cpu); 1529 } 1530 slab_lock(page); 1531 SetSlabFrozen(page); 1532 s->cpu_slab[cpu] = page; 1533 goto load_freelist; 1534 } 1535 return NULL; 1536debug: 1537 object = page->freelist; 1538 if (!alloc_debug_processing(s, page, object, addr)) 1539 goto another_slab; 1540 1541 page->inuse++; 1542 page->freelist = object[page->offset]; 1543 slab_unlock(page); 1544 return object; 1545} 1546 1547/* 1548 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc) 1549 * have the fastpath folded into their functions. So no function call 1550 * overhead for requests that can be satisfied on the fastpath. 1551 * 1552 * The fastpath works by first checking if the lockless freelist can be used. 1553 * If not then __slab_alloc is called for slow processing. 1554 * 1555 * Otherwise we can simply pick the next object from the lockless free list. 1556 */ 1557static void __always_inline *slab_alloc(struct kmem_cache *s, 1558 gfp_t gfpflags, int node, void *addr) 1559{ 1560 struct page *page; 1561 void **object; 1562 unsigned long flags; 1563 1564 local_irq_save(flags); 1565 page = s->cpu_slab[smp_processor_id()]; 1566 if (unlikely(!page || !page->lockless_freelist || 1567 (node != -1 && page_to_nid(page) != node))) 1568 1569 object = __slab_alloc(s, gfpflags, node, addr, page); 1570 1571 else { 1572 object = page->lockless_freelist; 1573 page->lockless_freelist = object[page->offset]; 1574 } 1575 local_irq_restore(flags); 1576 1577 if (unlikely((gfpflags & __GFP_ZERO) && object)) 1578 memset(object, 0, s->objsize); 1579 1580 return object; 1581} 1582 1583void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) 1584{ 1585 return slab_alloc(s, gfpflags, -1, __builtin_return_address(0)); 1586} 1587EXPORT_SYMBOL(kmem_cache_alloc); 1588 1589#ifdef CONFIG_NUMA 1590void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) 1591{ 1592 return slab_alloc(s, gfpflags, node, __builtin_return_address(0)); 1593} 1594EXPORT_SYMBOL(kmem_cache_alloc_node); 1595#endif 1596 1597/* 1598 * Slow patch handling. This may still be called frequently since objects 1599 * have a longer lifetime than the cpu slabs in most processing loads. 1600 * 1601 * So we still attempt to reduce cache line usage. Just take the slab 1602 * lock and free the item. If there is no additional partial page 1603 * handling required then we can return immediately. 1604 */ 1605static void __slab_free(struct kmem_cache *s, struct page *page, 1606 void *x, void *addr) 1607{ 1608 void *prior; 1609 void **object = (void *)x; 1610 1611 slab_lock(page); 1612 1613 if (unlikely(SlabDebug(page))) 1614 goto debug; 1615checks_ok: 1616 prior = object[page->offset] = page->freelist; 1617 page->freelist = object; 1618 page->inuse--; 1619 1620 if (unlikely(SlabFrozen(page))) 1621 goto out_unlock; 1622 1623 if (unlikely(!page->inuse)) 1624 goto slab_empty; 1625 1626 /* 1627 * Objects left in the slab. If it 1628 * was not on the partial list before 1629 * then add it. 1630 */ 1631 if (unlikely(!prior)) 1632 add_partial(get_node(s, page_to_nid(page)), page); 1633 1634out_unlock: 1635 slab_unlock(page); 1636 return; 1637 1638slab_empty: 1639 if (prior) 1640 /* 1641 * Slab still on the partial list. 1642 */ 1643 remove_partial(s, page); 1644 1645 slab_unlock(page); 1646 discard_slab(s, page); 1647 return; 1648 1649debug: 1650 if (!free_debug_processing(s, page, x, addr)) 1651 goto out_unlock; 1652 goto checks_ok; 1653} 1654 1655/* 1656 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that 1657 * can perform fastpath freeing without additional function calls. 1658 * 1659 * The fastpath is only possible if we are freeing to the current cpu slab 1660 * of this processor. This typically the case if we have just allocated 1661 * the item before. 1662 * 1663 * If fastpath is not possible then fall back to __slab_free where we deal 1664 * with all sorts of special processing. 1665 */ 1666static void __always_inline slab_free(struct kmem_cache *s, 1667 struct page *page, void *x, void *addr) 1668{ 1669 void **object = (void *)x; 1670 unsigned long flags; 1671 1672 local_irq_save(flags); 1673 debug_check_no_locks_freed(object, s->objsize); 1674 if (likely(page == s->cpu_slab[smp_processor_id()] && 1675 !SlabDebug(page))) { 1676 object[page->offset] = page->lockless_freelist; 1677 page->lockless_freelist = object; 1678 } else 1679 __slab_free(s, page, x, addr); 1680 1681 local_irq_restore(flags); 1682} 1683 1684void kmem_cache_free(struct kmem_cache *s, void *x) 1685{ 1686 struct page *page; 1687 1688 page = virt_to_head_page(x); 1689 1690 slab_free(s, page, x, __builtin_return_address(0)); 1691} 1692EXPORT_SYMBOL(kmem_cache_free); 1693 1694/* Figure out on which slab object the object resides */ 1695static struct page *get_object_page(const void *x) 1696{ 1697 struct page *page = virt_to_head_page(x); 1698 1699 if (!PageSlab(page)) 1700 return NULL; 1701 1702 return page; 1703} 1704 1705/* 1706 * Object placement in a slab is made very easy because we always start at 1707 * offset 0. If we tune the size of the object to the alignment then we can 1708 * get the required alignment by putting one properly sized object after 1709 * another. 1710 * 1711 * Notice that the allocation order determines the sizes of the per cpu 1712 * caches. Each processor has always one slab available for allocations. 1713 * Increasing the allocation order reduces the number of times that slabs 1714 * must be moved on and off the partial lists and is therefore a factor in 1715 * locking overhead. 1716 */ 1717 1718/* 1719 * Mininum / Maximum order of slab pages. This influences locking overhead 1720 * and slab fragmentation. A higher order reduces the number of partial slabs 1721 * and increases the number of allocations possible without having to 1722 * take the list_lock. 1723 */ 1724static int slub_min_order; 1725static int slub_max_order = DEFAULT_MAX_ORDER; 1726static int slub_min_objects = DEFAULT_MIN_OBJECTS; 1727 1728/* 1729 * Merge control. If this is set then no merging of slab caches will occur. 1730 * (Could be removed. This was introduced to pacify the merge skeptics.) 1731 */ 1732static int slub_nomerge; 1733 1734/* 1735 * Calculate the order of allocation given an slab object size. 1736 * 1737 * The order of allocation has significant impact on performance and other 1738 * system components. Generally order 0 allocations should be preferred since 1739 * order 0 does not cause fragmentation in the page allocator. Larger objects 1740 * be problematic to put into order 0 slabs because there may be too much 1741 * unused space left. We go to a higher order if more than 1/8th of the slab 1742 * would be wasted. 1743 * 1744 * In order to reach satisfactory performance we must ensure that a minimum 1745 * number of objects is in one slab. Otherwise we may generate too much 1746 * activity on the partial lists which requires taking the list_lock. This is 1747 * less a concern for large slabs though which are rarely used. 1748 * 1749 * slub_max_order specifies the order where we begin to stop considering the 1750 * number of objects in a slab as critical. If we reach slub_max_order then 1751 * we try to keep the page order as low as possible. So we accept more waste 1752 * of space in favor of a small page order. 1753 * 1754 * Higher order allocations also allow the placement of more objects in a 1755 * slab and thereby reduce object handling overhead. If the user has 1756 * requested a higher mininum order then we start with that one instead of 1757 * the smallest order which will fit the object. 1758 */ 1759static inline int slab_order(int size, int min_objects, 1760 int max_order, int fract_leftover) 1761{ 1762 int order; 1763 int rem; 1764 int min_order = slub_min_order; 1765 1766 /* 1767 * If we would create too many object per slab then reduce 1768 * the slab order even if it goes below slub_min_order. 1769 */ 1770 while (min_order > 0 && 1771 (PAGE_SIZE << min_order) >= MAX_OBJECTS_PER_SLAB * size) 1772 min_order--; 1773 1774 for (order = max(min_order, 1775 fls(min_objects * size - 1) - PAGE_SHIFT); 1776 order <= max_order; order++) { 1777 1778 unsigned long slab_size = PAGE_SIZE << order; 1779 1780 if (slab_size < min_objects * size) 1781 continue; 1782 1783 rem = slab_size % size; 1784 1785 if (rem <= slab_size / fract_leftover) 1786 break; 1787 1788 /* If the next size is too high then exit now */ 1789 if (slab_size * 2 >= MAX_OBJECTS_PER_SLAB * size) 1790 break; 1791 } 1792 1793 return order; 1794} 1795 1796static inline int calculate_order(int size) 1797{ 1798 int order; 1799 int min_objects; 1800 int fraction; 1801 1802 /* 1803 * Attempt to find best configuration for a slab. This 1804 * works by first attempting to generate a layout with 1805 * the best configuration and backing off gradually. 1806 * 1807 * First we reduce the acceptable waste in a slab. Then 1808 * we reduce the minimum objects required in a slab. 1809 */ 1810 min_objects = slub_min_objects; 1811 while (min_objects > 1) { 1812 fraction = 8; 1813 while (fraction >= 4) { 1814 order = slab_order(size, min_objects, 1815 slub_max_order, fraction); 1816 if (order <= slub_max_order) 1817 return order; 1818 fraction /= 2; 1819 } 1820 min_objects /= 2; 1821 } 1822 1823 /* 1824 * We were unable to place multiple objects in a slab. Now 1825 * lets see if we can place a single object there. 1826 */ 1827 order = slab_order(size, 1, slub_max_order, 1); 1828 if (order <= slub_max_order) 1829 return order; 1830 1831 /* 1832 * Doh this slab cannot be placed using slub_max_order. 1833 */ 1834 order = slab_order(size, 1, MAX_ORDER, 1); 1835 if (order <= MAX_ORDER) 1836 return order; 1837 return -ENOSYS; 1838} 1839 1840/* 1841 * Figure out what the alignment of the objects will be. 1842 */ 1843static unsigned long calculate_alignment(unsigned long flags, 1844 unsigned long align, unsigned long size) 1845{ 1846 /* 1847 * If the user wants hardware cache aligned objects then 1848 * follow that suggestion if the object is sufficiently 1849 * large. 1850 * 1851 * The hardware cache alignment cannot override the 1852 * specified alignment though. If that is greater 1853 * then use it. 1854 */ 1855 if ((flags & SLAB_HWCACHE_ALIGN) && 1856 size > cache_line_size() / 2) 1857 return max_t(unsigned long, align, cache_line_size()); 1858 1859 if (align < ARCH_SLAB_MINALIGN) 1860 return ARCH_SLAB_MINALIGN; 1861 1862 return ALIGN(align, sizeof(void *)); 1863} 1864 1865static void init_kmem_cache_node(struct kmem_cache_node *n) 1866{ 1867 n->nr_partial = 0; 1868 atomic_long_set(&n->nr_slabs, 0); 1869 spin_lock_init(&n->list_lock); 1870 INIT_LIST_HEAD(&n->partial); 1871#ifdef CONFIG_SLUB_DEBUG 1872 INIT_LIST_HEAD(&n->full); 1873#endif 1874} 1875 1876#ifdef CONFIG_NUMA 1877/* 1878 * No kmalloc_node yet so do it by hand. We know that this is the first 1879 * slab on the node for this slabcache. There are no concurrent accesses 1880 * possible. 1881 * 1882 * Note that this function only works on the kmalloc_node_cache 1883 * when allocating for the kmalloc_node_cache. 1884 */ 1885static struct kmem_cache_node *early_kmem_cache_node_alloc(gfp_t gfpflags, 1886 int node) 1887{ 1888 struct page *page; 1889 struct kmem_cache_node *n; 1890 1891 BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node)); 1892 1893 page = new_slab(kmalloc_caches, gfpflags, node); 1894 1895 BUG_ON(!page); 1896 if (page_to_nid(page) != node) { 1897 printk(KERN_ERR "SLUB: Unable to allocate memory from " 1898 "node %d\n", node); 1899 printk(KERN_ERR "SLUB: Allocating a useless per node structure " 1900 "in order to be able to continue\n"); 1901 } 1902 1903 n = page->freelist; 1904 BUG_ON(!n); 1905 page->freelist = get_freepointer(kmalloc_caches, n); 1906 page->inuse++; 1907 kmalloc_caches->node[node] = n; 1908#ifdef CONFIG_SLUB_DEBUG 1909 init_object(kmalloc_caches, n, 1); 1910 init_tracking(kmalloc_caches, n); 1911#endif 1912 init_kmem_cache_node(n); 1913 atomic_long_inc(&n->nr_slabs); 1914 add_partial(n, page); 1915 1916 /* 1917 * new_slab() disables interupts. If we do not reenable interrupts here 1918 * then bootup would continue with interrupts disabled. 1919 */ 1920 local_irq_enable(); 1921 return n; 1922} 1923 1924static void free_kmem_cache_nodes(struct kmem_cache *s) 1925{ 1926 int node; 1927 1928 for_each_node_state(node, N_NORMAL_MEMORY) { 1929 struct kmem_cache_node *n = s->node[node]; 1930 if (n && n != &s->local_node) 1931 kmem_cache_free(kmalloc_caches, n); 1932 s->node[node] = NULL; 1933 } 1934} 1935 1936static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags) 1937{ 1938 int node; 1939 int local_node; 1940 1941 if (slab_state >= UP) 1942 local_node = page_to_nid(virt_to_page(s)); 1943 else 1944 local_node = 0; 1945 1946 for_each_node_state(node, N_NORMAL_MEMORY) { 1947 struct kmem_cache_node *n; 1948 1949 if (local_node == node) 1950 n = &s->local_node; 1951 else { 1952 if (slab_state == DOWN) { 1953 n = early_kmem_cache_node_alloc(gfpflags, 1954 node); 1955 continue; 1956 } 1957 n = kmem_cache_alloc_node(kmalloc_caches, 1958 gfpflags, node); 1959 1960 if (!n) { 1961 free_kmem_cache_nodes(s); 1962 return 0; 1963 } 1964 1965 } 1966 s->node[node] = n; 1967 init_kmem_cache_node(n); 1968 } 1969 return 1; 1970} 1971#else 1972static void free_kmem_cache_nodes(struct kmem_cache *s) 1973{ 1974} 1975 1976static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags) 1977{ 1978 init_kmem_cache_node(&s->local_node); 1979 return 1; 1980} 1981#endif 1982 1983/* 1984 * calculate_sizes() determines the order and the distribution of data within 1985 * a slab object. 1986 */ 1987static int calculate_sizes(struct kmem_cache *s) 1988{ 1989 unsigned long flags = s->flags; 1990 unsigned long size = s->objsize; 1991 unsigned long align = s->align; 1992 1993 /* 1994 * Determine if we can poison the object itself. If the user of 1995 * the slab may touch the object after free or before allocation 1996 * then we should never poison the object itself. 1997 */ 1998 if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) && 1999 !s->ctor) 2000 s->flags |= __OBJECT_POISON; 2001 else 2002 s->flags &= ~__OBJECT_POISON; 2003 2004 /* 2005 * Round up object size to the next word boundary. We can only 2006 * place the free pointer at word boundaries and this determines 2007 * the possible location of the free pointer. 2008 */ 2009 size = ALIGN(size, sizeof(void *)); 2010 2011#ifdef CONFIG_SLUB_DEBUG 2012 /* 2013 * If we are Redzoning then check if there is some space between the 2014 * end of the object and the free pointer. If not then add an 2015 * additional word to have some bytes to store Redzone information. 2016 */ 2017 if ((flags & SLAB_RED_ZONE) && size == s->objsize) 2018 size += sizeof(void *); 2019#endif 2020 2021 /* 2022 * With that we have determined the number of bytes in actual use 2023 * by the object. This is the potential offset to the free pointer. 2024 */ 2025 s->inuse = size; 2026 2027 if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) || 2028 s->ctor)) { 2029 /* 2030 * Relocate free pointer after the object if it is not 2031 * permitted to overwrite the first word of the object on 2032 * kmem_cache_free. 2033 * 2034 * This is the case if we do RCU, have a constructor or 2035 * destructor or are poisoning the objects. 2036 */ 2037 s->offset = size; 2038 size += sizeof(void *); 2039 } 2040 2041#ifdef CONFIG_SLUB_DEBUG 2042 if (flags & SLAB_STORE_USER) 2043 /* 2044 * Need to store information about allocs and frees after 2045 * the object. 2046 */ 2047 size += 2 * sizeof(struct track); 2048 2049 if (flags & SLAB_RED_ZONE) 2050 /* 2051 * Add some empty padding so that we can catch 2052 * overwrites from earlier objects rather than let 2053 * tracking information or the free pointer be 2054 * corrupted if an user writes before the start 2055 * of the object. 2056 */ 2057 size += sizeof(void *); 2058#endif 2059 2060 /* 2061 * Determine the alignment based on various parameters that the 2062 * user specified and the dynamic determination of cache line size 2063 * on bootup. 2064 */ 2065 align = calculate_alignment(flags, align, s->objsize); 2066 2067 /* 2068 * SLUB stores one object immediately after another beginning from 2069 * offset 0. In order to align the objects we have to simply size 2070 * each object to conform to the alignment. 2071 */ 2072 size = ALIGN(size, align); 2073 s->size = size; 2074 2075 s->order = calculate_order(size); 2076 if (s->order < 0) 2077 return 0; 2078 2079 /* 2080 * Determine the number of objects per slab 2081 */ 2082 s->objects = (PAGE_SIZE << s->order) / size; 2083 2084 /* 2085 * Verify that the number of objects is within permitted limits. 2086 * The page->inuse field is only 16 bit wide! So we cannot have 2087 * more than 64k objects per slab. 2088 */ 2089 if (!s->objects || s->objects > MAX_OBJECTS_PER_SLAB) 2090 return 0; 2091 return 1; 2092 2093} 2094 2095static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags, 2096 const char *name, size_t size, 2097 size_t align, unsigned long flags, 2098 void (*ctor)(void *, struct kmem_cache *, unsigned long)) 2099{ 2100 memset(s, 0, kmem_size); 2101 s->name = name; 2102 s->ctor = ctor; 2103 s->objsize = size; 2104 s->align = align; 2105 s->flags = kmem_cache_flags(size, flags, name, ctor); 2106 2107 if (!calculate_sizes(s)) 2108 goto error; 2109 2110 s->refcount = 1; 2111#ifdef CONFIG_NUMA 2112 s->defrag_ratio = 100; 2113#endif 2114 2115 if (init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA)) 2116 return 1; 2117error: 2118 if (flags & SLAB_PANIC) 2119 panic("Cannot create slab %s size=%lu realsize=%u " 2120 "order=%u offset=%u flags=%lx\n", 2121 s->name, (unsigned long)size, s->size, s->order, 2122 s->offset, flags); 2123 return 0; 2124} 2125 2126/* 2127 * Check if a given pointer is valid 2128 */ 2129int kmem_ptr_validate(struct kmem_cache *s, const void *object) 2130{ 2131 struct page * page; 2132 2133 page = get_object_page(object); 2134 2135 if (!page || s != page->slab) 2136 /* No slab or wrong slab */ 2137 return 0; 2138 2139 if (!check_valid_pointer(s, page, object)) 2140 return 0; 2141 2142 /* 2143 * We could also check if the object is on the slabs freelist. 2144 * But this would be too expensive and it seems that the main 2145 * purpose of kmem_ptr_valid is to check if the object belongs 2146 * to a certain slab. 2147 */ 2148 return 1; 2149} 2150EXPORT_SYMBOL(kmem_ptr_validate); 2151 2152/* 2153 * Determine the size of a slab object 2154 */ 2155unsigned int kmem_cache_size(struct kmem_cache *s) 2156{ 2157 return s->objsize; 2158} 2159EXPORT_SYMBOL(kmem_cache_size); 2160 2161const char *kmem_cache_name(struct kmem_cache *s) 2162{ 2163 return s->name; 2164} 2165EXPORT_SYMBOL(kmem_cache_name); 2166 2167/* 2168 * Attempt to free all slabs on a node. Return the number of slabs we 2169 * were unable to free. 2170 */ 2171static int free_list(struct kmem_cache *s, struct kmem_cache_node *n, 2172 struct list_head *list) 2173{ 2174 int slabs_inuse = 0; 2175 unsigned long flags; 2176 struct page *page, *h; 2177 2178 spin_lock_irqsave(&n->list_lock, flags); 2179 list_for_each_entry_safe(page, h, list, lru) 2180 if (!page->inuse) { 2181 list_del(&page->lru); 2182 discard_slab(s, page); 2183 } else 2184 slabs_inuse++; 2185 spin_unlock_irqrestore(&n->list_lock, flags); 2186 return slabs_inuse; 2187} 2188 2189/* 2190 * Release all resources used by a slab cache. 2191 */ 2192static inline int kmem_cache_close(struct kmem_cache *s) 2193{ 2194 int node; 2195 2196 flush_all(s); 2197 2198 /* Attempt to free all objects */ 2199 for_each_node_state(node, N_NORMAL_MEMORY) { 2200 struct kmem_cache_node *n = get_node(s, node); 2201 2202 n->nr_partial -= free_list(s, n, &n->partial); 2203 if (atomic_long_read(&n->nr_slabs)) 2204 return 1; 2205 } 2206 free_kmem_cache_nodes(s); 2207 return 0; 2208} 2209 2210/* 2211 * Close a cache and release the kmem_cache structure 2212 * (must be used for caches created using kmem_cache_create) 2213 */ 2214void kmem_cache_destroy(struct kmem_cache *s) 2215{ 2216 down_write(&slub_lock); 2217 s->refcount--; 2218 if (!s->refcount) { 2219 list_del(&s->list); 2220 up_write(&slub_lock); 2221 if (kmem_cache_close(s)) 2222 WARN_ON(1); 2223 sysfs_slab_remove(s); 2224 kfree(s); 2225 } else 2226 up_write(&slub_lock); 2227} 2228EXPORT_SYMBOL(kmem_cache_destroy); 2229 2230/******************************************************************** 2231 * Kmalloc subsystem 2232 *******************************************************************/ 2233 2234struct kmem_cache kmalloc_caches[PAGE_SHIFT] __cacheline_aligned; 2235EXPORT_SYMBOL(kmalloc_caches); 2236 2237#ifdef CONFIG_ZONE_DMA 2238static struct kmem_cache *kmalloc_caches_dma[PAGE_SHIFT]; 2239#endif 2240 2241static int __init setup_slub_min_order(char *str) 2242{ 2243 get_option (&str, &slub_min_order); 2244 2245 return 1; 2246} 2247 2248__setup("slub_min_order=", setup_slub_min_order); 2249 2250static int __init setup_slub_max_order(char *str) 2251{ 2252 get_option (&str, &slub_max_order); 2253 2254 return 1; 2255} 2256 2257__setup("slub_max_order=", setup_slub_max_order); 2258 2259static int __init setup_slub_min_objects(char *str) 2260{ 2261 get_option (&str, &slub_min_objects); 2262 2263 return 1; 2264} 2265 2266__setup("slub_min_objects=", setup_slub_min_objects); 2267 2268static int __init setup_slub_nomerge(char *str) 2269{ 2270 slub_nomerge = 1; 2271 return 1; 2272} 2273 2274__setup("slub_nomerge", setup_slub_nomerge); 2275 2276static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s, 2277 const char *name, int size, gfp_t gfp_flags) 2278{ 2279 unsigned int flags = 0; 2280 2281 if (gfp_flags & SLUB_DMA) 2282 flags = SLAB_CACHE_DMA; 2283 2284 down_write(&slub_lock); 2285 if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN, 2286 flags, NULL)) 2287 goto panic; 2288 2289 list_add(&s->list, &slab_caches); 2290 up_write(&slub_lock); 2291 if (sysfs_slab_add(s)) 2292 goto panic; 2293 return s; 2294 2295panic: 2296 panic("Creation of kmalloc slab %s size=%d failed.\n", name, size); 2297} 2298 2299#ifdef CONFIG_ZONE_DMA 2300 2301static void sysfs_add_func(struct work_struct *w) 2302{ 2303 struct kmem_cache *s; 2304 2305 down_write(&slub_lock); 2306 list_for_each_entry(s, &slab_caches, list) { 2307 if (s->flags & __SYSFS_ADD_DEFERRED) { 2308 s->flags &= ~__SYSFS_ADD_DEFERRED; 2309 sysfs_slab_add(s); 2310 } 2311 } 2312 up_write(&slub_lock); 2313} 2314 2315static DECLARE_WORK(sysfs_add_work, sysfs_add_func); 2316 2317static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags) 2318{ 2319 struct kmem_cache *s; 2320 char *text; 2321 size_t realsize; 2322 2323 s = kmalloc_caches_dma[index]; 2324 if (s) 2325 return s; 2326 2327 /* Dynamically create dma cache */ 2328 if (flags & __GFP_WAIT) 2329 down_write(&slub_lock); 2330 else { 2331 if (!down_write_trylock(&slub_lock)) 2332 goto out; 2333 } 2334 2335 if (kmalloc_caches_dma[index]) 2336 goto unlock_out; 2337 2338 realsize = kmalloc_caches[index].objsize; 2339 text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d", (unsigned int)realsize), 2340 s = kmalloc(kmem_size, flags & ~SLUB_DMA); 2341 2342 if (!s || !text || !kmem_cache_open(s, flags, text, 2343 realsize, ARCH_KMALLOC_MINALIGN, 2344 SLAB_CACHE_DMA|__SYSFS_ADD_DEFERRED, NULL)) { 2345 kfree(s); 2346 kfree(text); 2347 goto unlock_out; 2348 } 2349 2350 list_add(&s->list, &slab_caches); 2351 kmalloc_caches_dma[index] = s; 2352 2353 schedule_work(&sysfs_add_work); 2354 2355unlock_out: 2356 up_write(&slub_lock); 2357out: 2358 return kmalloc_caches_dma[index]; 2359} 2360#endif 2361 2362/* 2363 * Conversion table for small slabs sizes / 8 to the index in the 2364 * kmalloc array. This is necessary for slabs < 192 since we have non power 2365 * of two cache sizes there. The size of larger slabs can be determined using 2366 * fls. 2367 */ 2368static s8 size_index[24] = { 2369 3, /* 8 */ 2370 4, /* 16 */ 2371 5, /* 24 */ 2372 5, /* 32 */ 2373 6, /* 40 */ 2374 6, /* 48 */ 2375 6, /* 56 */ 2376 6, /* 64 */ 2377 1, /* 72 */ 2378 1, /* 80 */ 2379 1, /* 88 */ 2380 1, /* 96 */ 2381 7, /* 104 */ 2382 7, /* 112 */ 2383 7, /* 120 */ 2384 7, /* 128 */ 2385 2, /* 136 */ 2386 2, /* 144 */ 2387 2, /* 152 */ 2388 2, /* 160 */ 2389 2, /* 168 */ 2390 2, /* 176 */ 2391 2, /* 184 */ 2392 2 /* 192 */ 2393}; 2394 2395static struct kmem_cache *get_slab(size_t size, gfp_t flags) 2396{ 2397 int index; 2398 2399 if (size <= 192) { 2400 if (!size) 2401 return ZERO_SIZE_PTR; 2402 2403 index = size_index[(size - 1) / 8]; 2404 } else 2405 index = fls(size - 1); 2406 2407#ifdef CONFIG_ZONE_DMA 2408 if (unlikely((flags & SLUB_DMA))) 2409 return dma_kmalloc_cache(index, flags); 2410 2411#endif 2412 return &kmalloc_caches[index]; 2413} 2414 2415void *__kmalloc(size_t size, gfp_t flags) 2416{ 2417 struct kmem_cache *s; 2418 2419 if (unlikely(size > PAGE_SIZE / 2)) 2420 return (void *)__get_free_pages(flags | __GFP_COMP, 2421 get_order(size)); 2422 2423 s = get_slab(size, flags); 2424 2425 if (unlikely(ZERO_OR_NULL_PTR(s))) 2426 return s; 2427 2428 return slab_alloc(s, flags, -1, __builtin_return_address(0)); 2429} 2430EXPORT_SYMBOL(__kmalloc); 2431 2432#ifdef CONFIG_NUMA 2433void *__kmalloc_node(size_t size, gfp_t flags, int node) 2434{ 2435 struct kmem_cache *s; 2436 2437 if (unlikely(size > PAGE_SIZE / 2)) 2438 return (void *)__get_free_pages(flags | __GFP_COMP, 2439 get_order(size)); 2440 2441 s = get_slab(size, flags); 2442 2443 if (unlikely(ZERO_OR_NULL_PTR(s))) 2444 return s; 2445 2446 return slab_alloc(s, flags, node, __builtin_return_address(0)); 2447} 2448EXPORT_SYMBOL(__kmalloc_node); 2449#endif 2450 2451size_t ksize(const void *object) 2452{ 2453 struct page *page; 2454 struct kmem_cache *s; 2455 2456 BUG_ON(!object); 2457 if (unlikely(object == ZERO_SIZE_PTR)) 2458 return 0; 2459 2460 page = get_object_page(object); 2461 BUG_ON(!page); 2462 s = page->slab; 2463 BUG_ON(!s); 2464 2465 /* 2466 * Debugging requires use of the padding between object 2467 * and whatever may come after it. 2468 */ 2469 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) 2470 return s->objsize; 2471 2472 /* 2473 * If we have the need to store the freelist pointer 2474 * back there or track user information then we can 2475 * only use the space before that information. 2476 */ 2477 if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER)) 2478 return s->inuse; 2479 2480 /* 2481 * Else we can use all the padding etc for the allocation 2482 */ 2483 return s->size; 2484} 2485EXPORT_SYMBOL(ksize); 2486 2487void kfree(const void *x) 2488{ 2489 struct page *page; 2490 2491 if (unlikely(ZERO_OR_NULL_PTR(x))) 2492 return; 2493 2494 page = virt_to_head_page(x); 2495 if (unlikely(!PageSlab(page))) { 2496 put_page(page); 2497 return; 2498 } 2499 slab_free(page->slab, page, (void *)x, __builtin_return_address(0)); 2500} 2501EXPORT_SYMBOL(kfree); 2502 2503/* 2504 * kmem_cache_shrink removes empty slabs from the partial lists and sorts 2505 * the remaining slabs by the number of items in use. The slabs with the 2506 * most items in use come first. New allocations will then fill those up 2507 * and thus they can be removed from the partial lists. 2508 * 2509 * The slabs with the least items are placed last. This results in them 2510 * being allocated from last increasing the chance that the last objects 2511 * are freed in them. 2512 */ 2513int kmem_cache_shrink(struct kmem_cache *s) 2514{ 2515 int node; 2516 int i; 2517 struct kmem_cache_node *n; 2518 struct page *page; 2519 struct page *t; 2520 struct list_head *slabs_by_inuse = 2521 kmalloc(sizeof(struct list_head) * s->objects, GFP_KERNEL); 2522 unsigned long flags; 2523 2524 if (!slabs_by_inuse) 2525 return -ENOMEM; 2526 2527 flush_all(s); 2528 for_each_node_state(node, N_NORMAL_MEMORY) { 2529 n = get_node(s, node); 2530 2531 if (!n->nr_partial) 2532 continue; 2533 2534 for (i = 0; i < s->objects; i++) 2535 INIT_LIST_HEAD(slabs_by_inuse + i); 2536 2537 spin_lock_irqsave(&n->list_lock, flags); 2538 2539 /* 2540 * Build lists indexed by the items in use in each slab. 2541 * 2542 * Note that concurrent frees may occur while we hold the 2543 * list_lock. page->inuse here is the upper limit. 2544 */ 2545 list_for_each_entry_safe(page, t, &n->partial, lru) { 2546 if (!page->inuse && slab_trylock(page)) { 2547 /* 2548 * Must hold slab lock here because slab_free 2549 * may have freed the last object and be 2550 * waiting to release the slab. 2551 */ 2552 list_del(&page->lru); 2553 n->nr_partial--; 2554 slab_unlock(page); 2555 discard_slab(s, page); 2556 } else { 2557 list_move(&page->lru, 2558 slabs_by_inuse + page->inuse); 2559 } 2560 } 2561 2562 /* 2563 * Rebuild the partial list with the slabs filled up most 2564 * first and the least used slabs at the end. 2565 */ 2566 for (i = s->objects - 1; i >= 0; i--) 2567 list_splice(slabs_by_inuse + i, n->partial.prev); 2568 2569 spin_unlock_irqrestore(&n->list_lock, flags); 2570 } 2571 2572 kfree(slabs_by_inuse); 2573 return 0; 2574} 2575EXPORT_SYMBOL(kmem_cache_shrink); 2576 2577/******************************************************************** 2578 * Basic setup of slabs 2579 *******************************************************************/ 2580 2581void __init kmem_cache_init(void) 2582{ 2583 int i; 2584 int caches = 0; 2585 2586#ifdef CONFIG_NUMA 2587 /* 2588 * Must first have the slab cache available for the allocations of the 2589 * struct kmem_cache_node's. There is special bootstrap code in 2590 * kmem_cache_open for slab_state == DOWN. 2591 */ 2592 create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node", 2593 sizeof(struct kmem_cache_node), GFP_KERNEL); 2594 kmalloc_caches[0].refcount = -1; 2595 caches++; 2596#endif 2597 2598 /* Able to allocate the per node structures */ 2599 slab_state = PARTIAL; 2600 2601 /* Caches that are not of the two-to-the-power-of size */ 2602 if (KMALLOC_MIN_SIZE <= 64) { 2603 create_kmalloc_cache(&kmalloc_caches[1], 2604 "kmalloc-96", 96, GFP_KERNEL); 2605 caches++; 2606 } 2607 if (KMALLOC_MIN_SIZE <= 128) { 2608 create_kmalloc_cache(&kmalloc_caches[2], 2609 "kmalloc-192", 192, GFP_KERNEL); 2610 caches++; 2611 } 2612 2613 for (i = KMALLOC_SHIFT_LOW; i < PAGE_SHIFT; i++) { 2614 create_kmalloc_cache(&kmalloc_caches[i], 2615 "kmalloc", 1 << i, GFP_KERNEL); 2616 caches++; 2617 } 2618 2619 2620 /* 2621 * Patch up the size_index table if we have strange large alignment 2622 * requirements for the kmalloc array. This is only the case for 2623 * mips it seems. The standard arches will not generate any code here. 2624 * 2625 * Largest permitted alignment is 256 bytes due to the way we 2626 * handle the index determination for the smaller caches. 2627 * 2628 * Make sure that nothing crazy happens if someone starts tinkering 2629 * around with ARCH_KMALLOC_MINALIGN 2630 */ 2631 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 2632 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); 2633 2634 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) 2635 size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW; 2636 2637 slab_state = UP; 2638 2639 /* Provide the correct kmalloc names now that the caches are up */ 2640 for (i = KMALLOC_SHIFT_LOW; i < PAGE_SHIFT; i++) 2641 kmalloc_caches[i]. name = 2642 kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i); 2643 2644#ifdef CONFIG_SMP 2645 register_cpu_notifier(&slab_notifier); 2646#endif 2647 2648 kmem_size = offsetof(struct kmem_cache, cpu_slab) + 2649 nr_cpu_ids * sizeof(struct page *); 2650 2651 printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d," 2652 " CPUs=%d, Nodes=%d\n", 2653 caches, cache_line_size(), 2654 slub_min_order, slub_max_order, slub_min_objects, 2655 nr_cpu_ids, nr_node_ids); 2656} 2657 2658/* 2659 * Find a mergeable slab cache 2660 */ 2661static int slab_unmergeable(struct kmem_cache *s) 2662{ 2663 if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE)) 2664 return 1; 2665 2666 if (s->ctor) 2667 return 1; 2668 2669 /* 2670 * We may have set a slab to be unmergeable during bootstrap. 2671 */ 2672 if (s->refcount < 0) 2673 return 1; 2674 2675 return 0; 2676} 2677 2678static struct kmem_cache *find_mergeable(size_t size, 2679 size_t align, unsigned long flags, const char *name, 2680 void (*ctor)(void *, struct kmem_cache *, unsigned long)) 2681{ 2682 struct kmem_cache *s; 2683 2684 if (slub_nomerge || (flags & SLUB_NEVER_MERGE)) 2685 return NULL; 2686 2687 if (ctor) 2688 return NULL; 2689 2690 size = ALIGN(size, sizeof(void *)); 2691 align = calculate_alignment(flags, align, size); 2692 size = ALIGN(size, align); 2693 flags = kmem_cache_flags(size, flags, name, NULL); 2694 2695 list_for_each_entry(s, &slab_caches, list) { 2696 if (slab_unmergeable(s)) 2697 continue; 2698 2699 if (size > s->size) 2700 continue; 2701 2702 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME)) 2703 continue; 2704 /* 2705 * Check if alignment is compatible. 2706 * Courtesy of Adrian Drzewiecki 2707 */ 2708 if ((s->size & ~(align -1)) != s->size) 2709 continue; 2710 2711 if (s->size - size >= sizeof(void *)) 2712 continue; 2713 2714 return s; 2715 } 2716 return NULL; 2717} 2718 2719struct kmem_cache *kmem_cache_create(const char *name, size_t size, 2720 size_t align, unsigned long flags, 2721 void (*ctor)(void *, struct kmem_cache *, unsigned long)) 2722{ 2723 struct kmem_cache *s; 2724 2725 down_write(&slub_lock); 2726 s = find_mergeable(size, align, flags, name, ctor); 2727 if (s) { 2728 s->refcount++; 2729 /* 2730 * Adjust the object sizes so that we clear 2731 * the complete object on kzalloc. 2732 */ 2733 s->objsize = max(s->objsize, (int)size); 2734 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *))); 2735 up_write(&slub_lock); 2736 if (sysfs_slab_alias(s, name)) 2737 goto err; 2738 return s; 2739 } 2740 s = kmalloc(kmem_size, GFP_KERNEL); 2741 if (s) { 2742 if (kmem_cache_open(s, GFP_KERNEL, name, 2743 size, align, flags, ctor)) { 2744 list_add(&s->list, &slab_caches); 2745 up_write(&slub_lock); 2746 if (sysfs_slab_add(s)) 2747 goto err; 2748 return s; 2749 } 2750 kfree(s); 2751 } 2752 up_write(&slub_lock); 2753 2754err: 2755 if (flags & SLAB_PANIC) 2756 panic("Cannot create slabcache %s\n", name); 2757 else 2758 s = NULL; 2759 return s; 2760} 2761EXPORT_SYMBOL(kmem_cache_create); 2762 2763#ifdef CONFIG_SMP 2764/* 2765 * Use the cpu notifier to insure that the cpu slabs are flushed when 2766 * necessary. 2767 */ 2768static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb, 2769 unsigned long action, void *hcpu) 2770{ 2771 long cpu = (long)hcpu; 2772 struct kmem_cache *s; 2773 unsigned long flags; 2774 2775 switch (action) { 2776 case CPU_UP_CANCELED: 2777 case CPU_UP_CANCELED_FROZEN: 2778 case CPU_DEAD: 2779 case CPU_DEAD_FROZEN: 2780 down_read(&slub_lock); 2781 list_for_each_entry(s, &slab_caches, list) { 2782 local_irq_save(flags); 2783 __flush_cpu_slab(s, cpu); 2784 local_irq_restore(flags); 2785 } 2786 up_read(&slub_lock); 2787 break; 2788 default: 2789 break; 2790 } 2791 return NOTIFY_OK; 2792} 2793 2794static struct notifier_block __cpuinitdata slab_notifier = 2795 { &slab_cpuup_callback, NULL, 0 }; 2796 2797#endif 2798 2799void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller) 2800{ 2801 struct kmem_cache *s; 2802 2803 if (unlikely(size > PAGE_SIZE / 2)) 2804 return (void *)__get_free_pages(gfpflags | __GFP_COMP, 2805 get_order(size)); 2806 s = get_slab(size, gfpflags); 2807 2808 if (unlikely(ZERO_OR_NULL_PTR(s))) 2809 return s; 2810 2811 return slab_alloc(s, gfpflags, -1, caller); 2812} 2813 2814void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, 2815 int node, void *caller) 2816{ 2817 struct kmem_cache *s; 2818 2819 if (unlikely(size > PAGE_SIZE / 2)) 2820 return (void *)__get_free_pages(gfpflags | __GFP_COMP, 2821 get_order(size)); 2822 s = get_slab(size, gfpflags); 2823 2824 if (unlikely(ZERO_OR_NULL_PTR(s))) 2825 return s; 2826 2827 return slab_alloc(s, gfpflags, node, caller); 2828} 2829 2830#if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG) 2831static int validate_slab(struct kmem_cache *s, struct page *page, 2832 unsigned long *map) 2833{ 2834 void *p; 2835 void *addr = page_address(page); 2836 2837 if (!check_slab(s, page) || 2838 !on_freelist(s, page, NULL)) 2839 return 0; 2840 2841 /* Now we know that a valid freelist exists */ 2842 bitmap_zero(map, s->objects); 2843 2844 for_each_free_object(p, s, page->freelist) { 2845 set_bit(slab_index(p, s, addr), map); 2846 if (!check_object(s, page, p, 0)) 2847 return 0; 2848 } 2849 2850 for_each_object(p, s, addr) 2851 if (!test_bit(slab_index(p, s, addr), map)) 2852 if (!check_object(s, page, p, 1)) 2853 return 0; 2854 return 1; 2855} 2856 2857static void validate_slab_slab(struct kmem_cache *s, struct page *page, 2858 unsigned long *map) 2859{ 2860 if (slab_trylock(page)) { 2861 validate_slab(s, page, map); 2862 slab_unlock(page); 2863 } else 2864 printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n", 2865 s->name, page); 2866 2867 if (s->flags & DEBUG_DEFAULT_FLAGS) { 2868 if (!SlabDebug(page)) 2869 printk(KERN_ERR "SLUB %s: SlabDebug not set " 2870 "on slab 0x%p\n", s->name, page); 2871 } else { 2872 if (SlabDebug(page)) 2873 printk(KERN_ERR "SLUB %s: SlabDebug set on " 2874 "slab 0x%p\n", s->name, page); 2875 } 2876} 2877 2878static int validate_slab_node(struct kmem_cache *s, 2879 struct kmem_cache_node *n, unsigned long *map) 2880{ 2881 unsigned long count = 0; 2882 struct page *page; 2883 unsigned long flags; 2884 2885 spin_lock_irqsave(&n->list_lock, flags); 2886 2887 list_for_each_entry(page, &n->partial, lru) { 2888 validate_slab_slab(s, page, map); 2889 count++; 2890 } 2891 if (count != n->nr_partial) 2892 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but " 2893 "counter=%ld\n", s->name, count, n->nr_partial); 2894 2895 if (!(s->flags & SLAB_STORE_USER)) 2896 goto out; 2897 2898 list_for_each_entry(page, &n->full, lru) { 2899 validate_slab_slab(s, page, map); 2900 count++; 2901 } 2902 if (count != atomic_long_read(&n->nr_slabs)) 2903 printk(KERN_ERR "SLUB: %s %ld slabs counted but " 2904 "counter=%ld\n", s->name, count, 2905 atomic_long_read(&n->nr_slabs)); 2906 2907out: 2908 spin_unlock_irqrestore(&n->list_lock, flags); 2909 return count; 2910} 2911 2912static long validate_slab_cache(struct kmem_cache *s) 2913{ 2914 int node; 2915 unsigned long count = 0; 2916 unsigned long *map = kmalloc(BITS_TO_LONGS(s->objects) * 2917 sizeof(unsigned long), GFP_KERNEL); 2918 2919 if (!map) 2920 return -ENOMEM; 2921 2922 flush_all(s); 2923 for_each_node_state(node, N_NORMAL_MEMORY) { 2924 struct kmem_cache_node *n = get_node(s, node); 2925 2926 count += validate_slab_node(s, n, map); 2927 } 2928 kfree(map); 2929 return count; 2930} 2931 2932#ifdef SLUB_RESILIENCY_TEST 2933static void resiliency_test(void) 2934{ 2935 u8 *p; 2936 2937 printk(KERN_ERR "SLUB resiliency testing\n"); 2938 printk(KERN_ERR "-----------------------\n"); 2939 printk(KERN_ERR "A. Corruption after allocation\n"); 2940 2941 p = kzalloc(16, GFP_KERNEL); 2942 p[16] = 0x12; 2943 printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer" 2944 " 0x12->0x%p\n\n", p + 16); 2945 2946 validate_slab_cache(kmalloc_caches + 4); 2947 2948 /* Hmmm... The next two are dangerous */ 2949 p = kzalloc(32, GFP_KERNEL); 2950 p[32 + sizeof(void *)] = 0x34; 2951 printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab" 2952 " 0x34 -> -0x%p\n", p); 2953 printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); 2954 2955 validate_slab_cache(kmalloc_caches + 5); 2956 p = kzalloc(64, GFP_KERNEL); 2957 p += 64 + (get_cycles() & 0xff) * sizeof(void *); 2958 *p = 0x56; 2959 printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n", 2960 p); 2961 printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); 2962 validate_slab_cache(kmalloc_caches + 6); 2963 2964 printk(KERN_ERR "\nB. Corruption after free\n"); 2965 p = kzalloc(128, GFP_KERNEL); 2966 kfree(p); 2967 *p = 0x78; 2968 printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p); 2969 validate_slab_cache(kmalloc_caches + 7); 2970 2971 p = kzalloc(256, GFP_KERNEL); 2972 kfree(p); 2973 p[50] = 0x9a; 2974 printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p); 2975 validate_slab_cache(kmalloc_caches + 8); 2976 2977 p = kzalloc(512, GFP_KERNEL); 2978 kfree(p); 2979 p[512] = 0xab; 2980 printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p); 2981 validate_slab_cache(kmalloc_caches + 9); 2982} 2983#else 2984static void resiliency_test(void) {}; 2985#endif 2986 2987/* 2988 * Generate lists of code addresses where slabcache objects are allocated 2989 * and freed. 2990 */ 2991 2992struct location { 2993 unsigned long count; 2994 void *addr; 2995 long long sum_time; 2996 long min_time; 2997 long max_time; 2998 long min_pid; 2999 long max_pid; 3000 cpumask_t cpus; 3001 nodemask_t nodes; 3002}; 3003 3004struct loc_track { 3005 unsigned long max; 3006 unsigned long count; 3007 struct location *loc; 3008}; 3009 3010static void free_loc_track(struct loc_track *t) 3011{ 3012 if (t->max) 3013 free_pages((unsigned long)t->loc, 3014 get_order(sizeof(struct location) * t->max)); 3015} 3016 3017static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags) 3018{ 3019 struct location *l; 3020 int order; 3021 3022 order = get_order(sizeof(struct location) * max); 3023 3024 l = (void *)__get_free_pages(flags, order); 3025 if (!l) 3026 return 0; 3027 3028 if (t->count) { 3029 memcpy(l, t->loc, sizeof(struct location) * t->count); 3030 free_loc_track(t); 3031 } 3032 t->max = max; 3033 t->loc = l; 3034 return 1; 3035} 3036 3037static int add_location(struct loc_track *t, struct kmem_cache *s, 3038 const struct track *track) 3039{ 3040 long start, end, pos; 3041 struct location *l; 3042 void *caddr; 3043 unsigned long age = jiffies - track->when; 3044 3045 start = -1; 3046 end = t->count; 3047 3048 for ( ; ; ) { 3049 pos = start + (end - start + 1) / 2; 3050 3051 /* 3052 * There is nothing at "end". If we end up there 3053 * we need to add something to before end. 3054 */ 3055 if (pos == end) 3056 break; 3057 3058 caddr = t->loc[pos].addr; 3059 if (track->addr == caddr) { 3060 3061 l = &t->loc[pos]; 3062 l->count++; 3063 if (track->when) { 3064 l->sum_time += age; 3065 if (age < l->min_time) 3066 l->min_time = age; 3067 if (age > l->max_time) 3068 l->max_time = age; 3069 3070 if (track->pid < l->min_pid) 3071 l->min_pid = track->pid; 3072 if (track->pid > l->max_pid) 3073 l->max_pid = track->pid; 3074 3075 cpu_set(track->cpu, l->cpus); 3076 } 3077 node_set(page_to_nid(virt_to_page(track)), l->nodes); 3078 return 1; 3079 } 3080 3081 if (track->addr < caddr) 3082 end = pos; 3083 else 3084 start = pos; 3085 } 3086 3087 /* 3088 * Not found. Insert new tracking element. 3089 */ 3090 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC)) 3091 return 0; 3092 3093 l = t->loc + pos; 3094 if (pos < t->count) 3095 memmove(l + 1, l, 3096 (t->count - pos) * sizeof(struct location)); 3097 t->count++; 3098 l->count = 1; 3099 l->addr = track->addr; 3100 l->sum_time = age; 3101 l->min_time = age; 3102 l->max_time = age; 3103 l->min_pid = track->pid; 3104 l->max_pid = track->pid; 3105 cpus_clear(l->cpus); 3106 cpu_set(track->cpu, l->cpus); 3107 nodes_clear(l->nodes); 3108 node_set(page_to_nid(virt_to_page(track)), l->nodes); 3109 return 1; 3110} 3111 3112static void process_slab(struct loc_track *t, struct kmem_cache *s, 3113 struct page *page, enum track_item alloc) 3114{ 3115 void *addr = page_address(page); 3116 DECLARE_BITMAP(map, s->objects); 3117 void *p; 3118 3119 bitmap_zero(map, s->objects); 3120 for_each_free_object(p, s, page->freelist) 3121 set_bit(slab_index(p, s, addr), map); 3122 3123 for_each_object(p, s, addr) 3124 if (!test_bit(slab_index(p, s, addr), map)) 3125 add_location(t, s, get_track(s, p, alloc)); 3126} 3127 3128static int list_locations(struct kmem_cache *s, char *buf, 3129 enum track_item alloc) 3130{ 3131 int n = 0; 3132 unsigned long i; 3133 struct loc_track t = { 0, 0, NULL }; 3134 int node; 3135 3136 if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location), 3137 GFP_KERNEL)) 3138 return sprintf(buf, "Out of memory\n"); 3139 3140 /* Push back cpu slabs */ 3141 flush_all(s); 3142 3143 for_each_node_state(node, N_NORMAL_MEMORY) { 3144 struct kmem_cache_node *n = get_node(s, node); 3145 unsigned long flags; 3146 struct page *page; 3147 3148 if (!atomic_long_read(&n->nr_slabs)) 3149 continue; 3150 3151 spin_lock_irqsave(&n->list_lock, flags); 3152 list_for_each_entry(page, &n->partial, lru) 3153 process_slab(&t, s, page, alloc); 3154 list_for_each_entry(page, &n->full, lru) 3155 process_slab(&t, s, page, alloc); 3156 spin_unlock_irqrestore(&n->list_lock, flags); 3157 } 3158 3159 for (i = 0; i < t.count; i++) { 3160 struct location *l = &t.loc[i]; 3161 3162 if (n > PAGE_SIZE - 100) 3163 break; 3164 n += sprintf(buf + n, "%7ld ", l->count); 3165 3166 if (l->addr) 3167 n += sprint_symbol(buf + n, (unsigned long)l->addr); 3168 else 3169 n += sprintf(buf + n, "<not-available>"); 3170 3171 if (l->sum_time != l->min_time) { 3172 unsigned long remainder; 3173 3174 n += sprintf(buf + n, " age=%ld/%ld/%ld", 3175 l->min_time, 3176 div_long_long_rem(l->sum_time, l->count, &remainder), 3177 l->max_time); 3178 } else 3179 n += sprintf(buf + n, " age=%ld", 3180 l->min_time); 3181 3182 if (l->min_pid != l->max_pid) 3183 n += sprintf(buf + n, " pid=%ld-%ld", 3184 l->min_pid, l->max_pid); 3185 else 3186 n += sprintf(buf + n, " pid=%ld", 3187 l->min_pid); 3188 3189 if (num_online_cpus() > 1 && !cpus_empty(l->cpus) && 3190 n < PAGE_SIZE - 60) { 3191 n += sprintf(buf + n, " cpus="); 3192 n += cpulist_scnprintf(buf + n, PAGE_SIZE - n - 50, 3193 l->cpus); 3194 } 3195 3196 if (num_online_nodes() > 1 && !nodes_empty(l->nodes) && 3197 n < PAGE_SIZE - 60) { 3198 n += sprintf(buf + n, " nodes="); 3199 n += nodelist_scnprintf(buf + n, PAGE_SIZE - n - 50, 3200 l->nodes); 3201 } 3202 3203 n += sprintf(buf + n, "\n"); 3204 } 3205 3206 free_loc_track(&t); 3207 if (!t.count) 3208 n += sprintf(buf, "No data\n"); 3209 return n; 3210} 3211 3212static unsigned long count_partial(struct kmem_cache_node *n) 3213{ 3214 unsigned long flags; 3215 unsigned long x = 0; 3216 struct page *page; 3217 3218 spin_lock_irqsave(&n->list_lock, flags); 3219 list_for_each_entry(page, &n->partial, lru) 3220 x += page->inuse; 3221 spin_unlock_irqrestore(&n->list_lock, flags); 3222 return x; 3223} 3224 3225enum slab_stat_type { 3226 SL_FULL, 3227 SL_PARTIAL, 3228 SL_CPU, 3229 SL_OBJECTS 3230}; 3231 3232#define SO_FULL (1 << SL_FULL) 3233#define SO_PARTIAL (1 << SL_PARTIAL) 3234#define SO_CPU (1 << SL_CPU) 3235#define SO_OBJECTS (1 << SL_OBJECTS) 3236 3237static unsigned long slab_objects(struct kmem_cache *s, 3238 char *buf, unsigned long flags) 3239{ 3240 unsigned long total = 0; 3241 int cpu; 3242 int node; 3243 int x; 3244 unsigned long *nodes; 3245 unsigned long *per_cpu; 3246 3247 nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL); 3248 per_cpu = nodes + nr_node_ids; 3249 3250 for_each_possible_cpu(cpu) { 3251 struct page *page = s->cpu_slab[cpu]; 3252 int node; 3253 3254 if (page) { 3255 node = page_to_nid(page); 3256 if (flags & SO_CPU) { 3257 int x = 0; 3258 3259 if (flags & SO_OBJECTS) 3260 x = page->inuse; 3261 else 3262 x = 1; 3263 total += x; 3264 nodes[node] += x; 3265 } 3266 per_cpu[node]++; 3267 } 3268 } 3269 3270 for_each_node_state(node, N_NORMAL_MEMORY) { 3271 struct kmem_cache_node *n = get_node(s, node); 3272 3273 if (flags & SO_PARTIAL) { 3274 if (flags & SO_OBJECTS) 3275 x = count_partial(n); 3276 else 3277 x = n->nr_partial; 3278 total += x; 3279 nodes[node] += x; 3280 } 3281 3282 if (flags & SO_FULL) { 3283 int full_slabs = atomic_long_read(&n->nr_slabs) 3284 - per_cpu[node] 3285 - n->nr_partial; 3286 3287 if (flags & SO_OBJECTS) 3288 x = full_slabs * s->objects; 3289 else 3290 x = full_slabs; 3291 total += x; 3292 nodes[node] += x; 3293 } 3294 } 3295 3296 x = sprintf(buf, "%lu", total); 3297#ifdef CONFIG_NUMA 3298 for_each_node_state(node, N_NORMAL_MEMORY) 3299 if (nodes[node]) 3300 x += sprintf(buf + x, " N%d=%lu", 3301 node, nodes[node]); 3302#endif 3303 kfree(nodes); 3304 return x + sprintf(buf + x, "\n"); 3305} 3306 3307static int any_slab_objects(struct kmem_cache *s) 3308{ 3309 int node; 3310 int cpu; 3311 3312 for_each_possible_cpu(cpu) 3313 if (s->cpu_slab[cpu]) 3314 return 1; 3315 3316 for_each_node(node) { 3317 struct kmem_cache_node *n = get_node(s, node); 3318 3319 if (n->nr_partial || atomic_long_read(&n->nr_slabs)) 3320 return 1; 3321 } 3322 return 0; 3323} 3324 3325#define to_slab_attr(n) container_of(n, struct slab_attribute, attr) 3326#define to_slab(n) container_of(n, struct kmem_cache, kobj); 3327 3328struct slab_attribute { 3329 struct attribute attr; 3330 ssize_t (*show)(struct kmem_cache *s, char *buf); 3331 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count); 3332}; 3333 3334#define SLAB_ATTR_RO(_name) \ 3335 static struct slab_attribute _name##_attr = __ATTR_RO(_name) 3336 3337#define SLAB_ATTR(_name) \ 3338 static struct slab_attribute _name##_attr = \ 3339 __ATTR(_name, 0644, _name##_show, _name##_store) 3340 3341static ssize_t slab_size_show(struct kmem_cache *s, char *buf) 3342{ 3343 return sprintf(buf, "%d\n", s->size); 3344} 3345SLAB_ATTR_RO(slab_size); 3346 3347static ssize_t align_show(struct kmem_cache *s, char *buf) 3348{ 3349 return sprintf(buf, "%d\n", s->align); 3350} 3351SLAB_ATTR_RO(align); 3352 3353static ssize_t object_size_show(struct kmem_cache *s, char *buf) 3354{ 3355 return sprintf(buf, "%d\n", s->objsize); 3356} 3357SLAB_ATTR_RO(object_size); 3358 3359static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf) 3360{ 3361 return sprintf(buf, "%d\n", s->objects); 3362} 3363SLAB_ATTR_RO(objs_per_slab); 3364 3365static ssize_t order_show(struct kmem_cache *s, char *buf) 3366{ 3367 return sprintf(buf, "%d\n", s->order); 3368} 3369SLAB_ATTR_RO(order); 3370 3371static ssize_t ctor_show(struct kmem_cache *s, char *buf) 3372{ 3373 if (s->ctor) { 3374 int n = sprint_symbol(buf, (unsigned long)s->ctor); 3375 3376 return n + sprintf(buf + n, "\n"); 3377 } 3378 return 0; 3379} 3380SLAB_ATTR_RO(ctor); 3381 3382static ssize_t aliases_show(struct kmem_cache *s, char *buf) 3383{ 3384 return sprintf(buf, "%d\n", s->refcount - 1); 3385} 3386SLAB_ATTR_RO(aliases); 3387 3388static ssize_t slabs_show(struct kmem_cache *s, char *buf) 3389{ 3390 return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU); 3391} 3392SLAB_ATTR_RO(slabs); 3393 3394static ssize_t partial_show(struct kmem_cache *s, char *buf) 3395{ 3396 return slab_objects(s, buf, SO_PARTIAL); 3397} 3398SLAB_ATTR_RO(partial); 3399 3400static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf) 3401{ 3402 return slab_objects(s, buf, SO_CPU); 3403} 3404SLAB_ATTR_RO(cpu_slabs); 3405 3406static ssize_t objects_show(struct kmem_cache *s, char *buf) 3407{ 3408 return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU|SO_OBJECTS); 3409} 3410SLAB_ATTR_RO(objects); 3411 3412static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf) 3413{ 3414 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE)); 3415} 3416 3417static ssize_t sanity_checks_store(struct kmem_cache *s, 3418 const char *buf, size_t length) 3419{ 3420 s->flags &= ~SLAB_DEBUG_FREE; 3421 if (buf[0] == '1') 3422 s->flags |= SLAB_DEBUG_FREE; 3423 return length; 3424} 3425SLAB_ATTR(sanity_checks); 3426 3427static ssize_t trace_show(struct kmem_cache *s, char *buf) 3428{ 3429 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE)); 3430} 3431 3432static ssize_t trace_store(struct kmem_cache *s, const char *buf, 3433 size_t length) 3434{ 3435 s->flags &= ~SLAB_TRACE; 3436 if (buf[0] == '1') 3437 s->flags |= SLAB_TRACE; 3438 return length; 3439} 3440SLAB_ATTR(trace); 3441 3442static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf) 3443{ 3444 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT)); 3445} 3446 3447static ssize_t reclaim_account_store(struct kmem_cache *s, 3448 const char *buf, size_t length) 3449{ 3450 s->flags &= ~SLAB_RECLAIM_ACCOUNT; 3451 if (buf[0] == '1') 3452 s->flags |= SLAB_RECLAIM_ACCOUNT; 3453 return length; 3454} 3455SLAB_ATTR(reclaim_account); 3456 3457static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf) 3458{ 3459 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN)); 3460} 3461SLAB_ATTR_RO(hwcache_align); 3462 3463#ifdef CONFIG_ZONE_DMA 3464static ssize_t cache_dma_show(struct kmem_cache *s, char *buf) 3465{ 3466 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA)); 3467} 3468SLAB_ATTR_RO(cache_dma); 3469#endif 3470 3471static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf) 3472{ 3473 return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU)); 3474} 3475SLAB_ATTR_RO(destroy_by_rcu); 3476 3477static ssize_t red_zone_show(struct kmem_cache *s, char *buf) 3478{ 3479 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE)); 3480} 3481 3482static ssize_t red_zone_store(struct kmem_cache *s, 3483 const char *buf, size_t length) 3484{ 3485 if (any_slab_objects(s)) 3486 return -EBUSY; 3487 3488 s->flags &= ~SLAB_RED_ZONE; 3489 if (buf[0] == '1') 3490 s->flags |= SLAB_RED_ZONE; 3491 calculate_sizes(s); 3492 return length; 3493} 3494SLAB_ATTR(red_zone); 3495 3496static ssize_t poison_show(struct kmem_cache *s, char *buf) 3497{ 3498 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON)); 3499} 3500 3501static ssize_t poison_store(struct kmem_cache *s, 3502 const char *buf, size_t length) 3503{ 3504 if (any_slab_objects(s)) 3505 return -EBUSY; 3506 3507 s->flags &= ~SLAB_POISON; 3508 if (buf[0] == '1') 3509 s->flags |= SLAB_POISON; 3510 calculate_sizes(s); 3511 return length; 3512} 3513SLAB_ATTR(poison); 3514 3515static ssize_t store_user_show(struct kmem_cache *s, char *buf) 3516{ 3517 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER)); 3518} 3519 3520static ssize_t store_user_store(struct kmem_cache *s, 3521 const char *buf, size_t length) 3522{ 3523 if (any_slab_objects(s)) 3524 return -EBUSY; 3525 3526 s->flags &= ~SLAB_STORE_USER; 3527 if (buf[0] == '1') 3528 s->flags |= SLAB_STORE_USER; 3529 calculate_sizes(s); 3530 return length; 3531} 3532SLAB_ATTR(store_user); 3533 3534static ssize_t validate_show(struct kmem_cache *s, char *buf) 3535{ 3536 return 0; 3537} 3538 3539static ssize_t validate_store(struct kmem_cache *s, 3540 const char *buf, size_t length) 3541{ 3542 int ret = -EINVAL; 3543 3544 if (buf[0] == '1') { 3545 ret = validate_slab_cache(s); 3546 if (ret >= 0) 3547 ret = length; 3548 } 3549 return ret; 3550} 3551SLAB_ATTR(validate); 3552 3553static ssize_t shrink_show(struct kmem_cache *s, char *buf) 3554{ 3555 return 0; 3556} 3557 3558static ssize_t shrink_store(struct kmem_cache *s, 3559 const char *buf, size_t length) 3560{ 3561 if (buf[0] == '1') { 3562 int rc = kmem_cache_shrink(s); 3563 3564 if (rc) 3565 return rc; 3566 } else 3567 return -EINVAL; 3568 return length; 3569} 3570SLAB_ATTR(shrink); 3571 3572static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf) 3573{ 3574 if (!(s->flags & SLAB_STORE_USER)) 3575 return -ENOSYS; 3576 return list_locations(s, buf, TRACK_ALLOC); 3577} 3578SLAB_ATTR_RO(alloc_calls); 3579 3580static ssize_t free_calls_show(struct kmem_cache *s, char *buf) 3581{ 3582 if (!(s->flags & SLAB_STORE_USER)) 3583 return -ENOSYS; 3584 return list_locations(s, buf, TRACK_FREE); 3585} 3586SLAB_ATTR_RO(free_calls); 3587 3588#ifdef CONFIG_NUMA 3589static ssize_t defrag_ratio_show(struct kmem_cache *s, char *buf) 3590{ 3591 return sprintf(buf, "%d\n", s->defrag_ratio / 10); 3592} 3593 3594static ssize_t defrag_ratio_store(struct kmem_cache *s, 3595 const char *buf, size_t length) 3596{ 3597 int n = simple_strtoul(buf, NULL, 10); 3598 3599 if (n < 100) 3600 s->defrag_ratio = n * 10; 3601 return length; 3602} 3603SLAB_ATTR(defrag_ratio); 3604#endif 3605 3606static struct attribute * slab_attrs[] = { 3607 &slab_size_attr.attr, 3608 &object_size_attr.attr, 3609 &objs_per_slab_attr.attr, 3610 &order_attr.attr, 3611 &objects_attr.attr, 3612 &slabs_attr.attr, 3613 &partial_attr.attr, 3614 &cpu_slabs_attr.attr, 3615 &ctor_attr.attr, 3616 &aliases_attr.attr, 3617 &align_attr.attr, 3618 &sanity_checks_attr.attr, 3619 &trace_attr.attr, 3620 &hwcache_align_attr.attr, 3621 &reclaim_account_attr.attr, 3622 &destroy_by_rcu_attr.attr, 3623 &red_zone_attr.attr, 3624 &poison_attr.attr, 3625 &store_user_attr.attr, 3626 &validate_attr.attr, 3627 &shrink_attr.attr, 3628 &alloc_calls_attr.attr, 3629 &free_calls_attr.attr, 3630#ifdef CONFIG_ZONE_DMA 3631 &cache_dma_attr.attr, 3632#endif 3633#ifdef CONFIG_NUMA 3634 &defrag_ratio_attr.attr, 3635#endif 3636 NULL 3637}; 3638 3639static struct attribute_group slab_attr_group = { 3640 .attrs = slab_attrs, 3641}; 3642 3643static ssize_t slab_attr_show(struct kobject *kobj, 3644 struct attribute *attr, 3645 char *buf) 3646{ 3647 struct slab_attribute *attribute; 3648 struct kmem_cache *s; 3649 int err; 3650 3651 attribute = to_slab_attr(attr); 3652 s = to_slab(kobj); 3653 3654 if (!attribute->show) 3655 return -EIO; 3656 3657 err = attribute->show(s, buf); 3658 3659 return err; 3660} 3661 3662static ssize_t slab_attr_store(struct kobject *kobj, 3663 struct attribute *attr, 3664 const char *buf, size_t len) 3665{ 3666 struct slab_attribute *attribute; 3667 struct kmem_cache *s; 3668 int err; 3669 3670 attribute = to_slab_attr(attr); 3671 s = to_slab(kobj); 3672 3673 if (!attribute->store) 3674 return -EIO; 3675 3676 err = attribute->store(s, buf, len); 3677 3678 return err; 3679} 3680 3681static struct sysfs_ops slab_sysfs_ops = { 3682 .show = slab_attr_show, 3683 .store = slab_attr_store, 3684}; 3685 3686static struct kobj_type slab_ktype = { 3687 .sysfs_ops = &slab_sysfs_ops, 3688}; 3689 3690static int uevent_filter(struct kset *kset, struct kobject *kobj) 3691{ 3692 struct kobj_type *ktype = get_ktype(kobj); 3693 3694 if (ktype == &slab_ktype) 3695 return 1; 3696 return 0; 3697} 3698 3699static struct kset_uevent_ops slab_uevent_ops = { 3700 .filter = uevent_filter, 3701}; 3702 3703static decl_subsys(slab, &slab_ktype, &slab_uevent_ops); 3704 3705#define ID_STR_LENGTH 64 3706 3707/* Create a unique string id for a slab cache: 3708 * format 3709 * :[flags-]size:[memory address of kmemcache] 3710 */ 3711static char *create_unique_id(struct kmem_cache *s) 3712{ 3713 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); 3714 char *p = name; 3715 3716 BUG_ON(!name); 3717 3718 *p++ = ':'; 3719 /* 3720 * First flags affecting slabcache operations. We will only 3721 * get here for aliasable slabs so we do not need to support 3722 * too many flags. The flags here must cover all flags that 3723 * are matched during merging to guarantee that the id is 3724 * unique. 3725 */ 3726 if (s->flags & SLAB_CACHE_DMA) 3727 *p++ = 'd'; 3728 if (s->flags & SLAB_RECLAIM_ACCOUNT) 3729 *p++ = 'a'; 3730 if (s->flags & SLAB_DEBUG_FREE) 3731 *p++ = 'F'; 3732 if (p != name + 1) 3733 *p++ = '-'; 3734 p += sprintf(p, "%07d", s->size); 3735 BUG_ON(p > name + ID_STR_LENGTH - 1); 3736 return name; 3737} 3738 3739static int sysfs_slab_add(struct kmem_cache *s) 3740{ 3741 int err; 3742 const char *name; 3743 int unmergeable; 3744 3745 if (slab_state < SYSFS) 3746 /* Defer until later */ 3747 return 0; 3748 3749 unmergeable = slab_unmergeable(s); 3750 if (unmergeable) { 3751 /* 3752 * Slabcache can never be merged so we can use the name proper. 3753 * This is typically the case for debug situations. In that 3754 * case we can catch duplicate names easily. 3755 */ 3756 sysfs_remove_link(&slab_subsys.kobj, s->name); 3757 name = s->name; 3758 } else { 3759 /* 3760 * Create a unique name for the slab as a target 3761 * for the symlinks. 3762 */ 3763 name = create_unique_id(s); 3764 } 3765 3766 kobj_set_kset_s(s, slab_subsys); 3767 kobject_set_name(&s->kobj, name); 3768 kobject_init(&s->kobj); 3769 err = kobject_add(&s->kobj); 3770 if (err) 3771 return err; 3772 3773 err = sysfs_create_group(&s->kobj, &slab_attr_group); 3774 if (err) 3775 return err; 3776 kobject_uevent(&s->kobj, KOBJ_ADD); 3777 if (!unmergeable) { 3778 /* Setup first alias */ 3779 sysfs_slab_alias(s, s->name); 3780 kfree(name); 3781 } 3782 return 0; 3783} 3784 3785static void sysfs_slab_remove(struct kmem_cache *s) 3786{ 3787 kobject_uevent(&s->kobj, KOBJ_REMOVE); 3788 kobject_del(&s->kobj); 3789} 3790 3791/* 3792 * Need to buffer aliases during bootup until sysfs becomes 3793 * available lest we loose that information. 3794 */ 3795struct saved_alias { 3796 struct kmem_cache *s; 3797 const char *name; 3798 struct saved_alias *next; 3799}; 3800 3801static struct saved_alias *alias_list; 3802 3803static int sysfs_slab_alias(struct kmem_cache *s, const char *name) 3804{ 3805 struct saved_alias *al; 3806 3807 if (slab_state == SYSFS) { 3808 /* 3809 * If we have a leftover link then remove it. 3810 */ 3811 sysfs_remove_link(&slab_subsys.kobj, name); 3812 return sysfs_create_link(&slab_subsys.kobj, 3813 &s->kobj, name); 3814 } 3815 3816 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL); 3817 if (!al) 3818 return -ENOMEM; 3819 3820 al->s = s; 3821 al->name = name; 3822 al->next = alias_list; 3823 alias_list = al; 3824 return 0; 3825} 3826 3827static int __init slab_sysfs_init(void) 3828{ 3829 struct kmem_cache *s; 3830 int err; 3831 3832 err = subsystem_register(&slab_subsys); 3833 if (err) { 3834 printk(KERN_ERR "Cannot register slab subsystem.\n"); 3835 return -ENOSYS; 3836 } 3837 3838 slab_state = SYSFS; 3839 3840 list_for_each_entry(s, &slab_caches, list) { 3841 err = sysfs_slab_add(s); 3842 if (err) 3843 printk(KERN_ERR "SLUB: Unable to add boot slab %s" 3844 " to sysfs\n", s->name); 3845 } 3846 3847 while (alias_list) { 3848 struct saved_alias *al = alias_list; 3849 3850 alias_list = alias_list->next; 3851 err = sysfs_slab_alias(al->s, al->name); 3852 if (err) 3853 printk(KERN_ERR "SLUB: Unable to add boot slab alias" 3854 " %s to sysfs\n", s->name); 3855 kfree(al); 3856 } 3857 3858 resiliency_test(); 3859 return 0; 3860} 3861 3862__initcall(slab_sysfs_init); 3863#endif 3864