slub.c 130 KB

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  1. /*
  2. * SLUB: A slab allocator that limits cache line use instead of queuing
  3. * objects in per cpu and per node lists.
  4. *
  5. * The allocator synchronizes using per slab locks or atomic operatios
  6. * and only uses a centralized lock to manage a pool of partial slabs.
  7. *
  8. * (C) 2007 SGI, Christoph Lameter
  9. * (C) 2011 Linux Foundation, Christoph Lameter
  10. */
  11. #include <linux/mm.h>
  12. #include <linux/swap.h> /* struct reclaim_state */
  13. #include <linux/module.h>
  14. #include <linux/bit_spinlock.h>
  15. #include <linux/interrupt.h>
  16. #include <linux/bitops.h>
  17. #include <linux/slab.h>
  18. #include <linux/proc_fs.h>
  19. #include <linux/seq_file.h>
  20. #include <linux/kmemcheck.h>
  21. #include <linux/cpu.h>
  22. #include <linux/cpuset.h>
  23. #include <linux/mempolicy.h>
  24. #include <linux/ctype.h>
  25. #include <linux/debugobjects.h>
  26. #include <linux/kallsyms.h>
  27. #include <linux/memory.h>
  28. #include <linux/math64.h>
  29. #include <linux/fault-inject.h>
  30. #include <linux/stacktrace.h>
  31. #include <linux/prefetch.h>
  32. #include <trace/events/kmem.h>
  33. #ifdef CONFIG_SEC_DEBUG_DOUBLE_FREE
  34. #include <mach/sec_debug.h>
  35. #endif
  36. /*
  37. * Lock order:
  38. * 1. slub_lock (Global Semaphore)
  39. * 2. node->list_lock
  40. * 3. slab_lock(page) (Only on some arches and for debugging)
  41. *
  42. * slub_lock
  43. *
  44. * The role of the slub_lock is to protect the list of all the slabs
  45. * and to synchronize major metadata changes to slab cache structures.
  46. *
  47. * The slab_lock is only used for debugging and on arches that do not
  48. * have the ability to do a cmpxchg_double. It only protects the second
  49. * double word in the page struct. Meaning
  50. * A. page->freelist -> List of object free in a page
  51. * B. page->counters -> Counters of objects
  52. * C. page->frozen -> frozen state
  53. *
  54. * If a slab is frozen then it is exempt from list management. It is not
  55. * on any list. The processor that froze the slab is the one who can
  56. * perform list operations on the page. Other processors may put objects
  57. * onto the freelist but the processor that froze the slab is the only
  58. * one that can retrieve the objects from the page's freelist.
  59. *
  60. * The list_lock protects the partial and full list on each node and
  61. * the partial slab counter. If taken then no new slabs may be added or
  62. * removed from the lists nor make the number of partial slabs be modified.
  63. * (Note that the total number of slabs is an atomic value that may be
  64. * modified without taking the list lock).
  65. *
  66. * The list_lock is a centralized lock and thus we avoid taking it as
  67. * much as possible. As long as SLUB does not have to handle partial
  68. * slabs, operations can continue without any centralized lock. F.e.
  69. * allocating a long series of objects that fill up slabs does not require
  70. * the list lock.
  71. * Interrupts are disabled during allocation and deallocation in order to
  72. * make the slab allocator safe to use in the context of an irq. In addition
  73. * interrupts are disabled to ensure that the processor does not change
  74. * while handling per_cpu slabs, due to kernel preemption.
  75. *
  76. * SLUB assigns one slab for allocation to each processor.
  77. * Allocations only occur from these slabs called cpu slabs.
  78. *
  79. * Slabs with free elements are kept on a partial list and during regular
  80. * operations no list for full slabs is used. If an object in a full slab is
  81. * freed then the slab will show up again on the partial lists.
  82. * We track full slabs for debugging purposes though because otherwise we
  83. * cannot scan all objects.
  84. *
  85. * Slabs are freed when they become empty. Teardown and setup is
  86. * minimal so we rely on the page allocators per cpu caches for
  87. * fast frees and allocs.
  88. *
  89. * Overloading of page flags that are otherwise used for LRU management.
  90. *
  91. * PageActive The slab is frozen and exempt from list processing.
  92. * This means that the slab is dedicated to a purpose
  93. * such as satisfying allocations for a specific
  94. * processor. Objects may be freed in the slab while
  95. * it is frozen but slab_free will then skip the usual
  96. * list operations. It is up to the processor holding
  97. * the slab to integrate the slab into the slab lists
  98. * when the slab is no longer needed.
  99. *
  100. * One use of this flag is to mark slabs that are
  101. * used for allocations. Then such a slab becomes a cpu
  102. * slab. The cpu slab may be equipped with an additional
  103. * freelist that allows lockless access to
  104. * free objects in addition to the regular freelist
  105. * that requires the slab lock.
  106. *
  107. * PageError Slab requires special handling due to debug
  108. * options set. This moves slab handling out of
  109. * the fast path and disables lockless freelists.
  110. */
  111. #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
  112. SLAB_TRACE | SLAB_DEBUG_FREE)
  113. static inline int kmem_cache_debug(struct kmem_cache *s)
  114. {
  115. #ifdef CONFIG_SLUB_DEBUG
  116. return unlikely(s->flags & SLAB_DEBUG_FLAGS);
  117. #else
  118. return 0;
  119. #endif
  120. }
  121. /*
  122. * Issues still to be resolved:
  123. *
  124. * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
  125. *
  126. * - Variable sizing of the per node arrays
  127. */
  128. /* Enable to test recovery from slab corruption on boot */
  129. #undef SLUB_RESILIENCY_TEST
  130. /* Enable to log cmpxchg failures */
  131. #undef SLUB_DEBUG_CMPXCHG
  132. /*
  133. * Mininum number of partial slabs. These will be left on the partial
  134. * lists even if they are empty. kmem_cache_shrink may reclaim them.
  135. */
  136. #define MIN_PARTIAL 5
  137. /*
  138. * Maximum number of desirable partial slabs.
  139. * The existence of more partial slabs makes kmem_cache_shrink
  140. * sort the partial list by the number of objects in the.
  141. */
  142. #define MAX_PARTIAL 10
  143. #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
  144. SLAB_POISON | SLAB_STORE_USER)
  145. /*
  146. * Debugging flags that require metadata to be stored in the slab. These get
  147. * disabled when slub_debug=O is used and a cache's min order increases with
  148. * metadata.
  149. */
  150. #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
  151. /*
  152. * Set of flags that will prevent slab merging
  153. */
  154. #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
  155. SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
  156. SLAB_FAILSLAB)
  157. #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
  158. SLAB_CACHE_DMA | SLAB_NOTRACK)
  159. #define OO_SHIFT 16
  160. #define OO_MASK ((1 << OO_SHIFT) - 1)
  161. #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
  162. /* Internal SLUB flags */
  163. #define __OBJECT_POISON 0x80000000UL /* Poison object */
  164. #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
  165. static int kmem_size = sizeof(struct kmem_cache);
  166. #ifdef CONFIG_SMP
  167. static struct notifier_block slab_notifier;
  168. #endif
  169. static enum {
  170. DOWN, /* No slab functionality available */
  171. PARTIAL, /* Kmem_cache_node works */
  172. UP, /* Everything works but does not show up in sysfs */
  173. SYSFS /* Sysfs up */
  174. } slab_state = DOWN;
  175. /* A list of all slab caches on the system */
  176. static DECLARE_RWSEM(slub_lock);
  177. static LIST_HEAD(slab_caches);
  178. /*
  179. * Tracking user of a slab.
  180. */
  181. #define TRACK_ADDRS_COUNT 16
  182. struct track {
  183. unsigned long addr; /* Called from address */
  184. #ifdef CONFIG_STACKTRACE
  185. unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
  186. #endif
  187. int cpu; /* Was running on cpu */
  188. int pid; /* Pid context */
  189. unsigned long when; /* When did the operation occur */
  190. };
  191. enum track_item { TRACK_ALLOC, TRACK_FREE };
  192. #ifdef CONFIG_SYSFS
  193. static int sysfs_slab_add(struct kmem_cache *);
  194. static int sysfs_slab_alias(struct kmem_cache *, const char *);
  195. static void sysfs_slab_remove(struct kmem_cache *);
  196. #else
  197. static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
  198. static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
  199. { return 0; }
  200. static inline void sysfs_slab_remove(struct kmem_cache *s)
  201. {
  202. kfree(s->name);
  203. kfree(s);
  204. }
  205. #endif
  206. static inline void stat(const struct kmem_cache *s, enum stat_item si)
  207. {
  208. #ifdef CONFIG_SLUB_STATS
  209. __this_cpu_inc(s->cpu_slab->stat[si]);
  210. #endif
  211. }
  212. /********************************************************************
  213. * Core slab cache functions
  214. *******************************************************************/
  215. int slab_is_available(void)
  216. {
  217. return slab_state >= UP;
  218. }
  219. static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
  220. {
  221. return s->node[node];
  222. }
  223. /* Verify that a pointer has an address that is valid within a slab page */
  224. static inline int check_valid_pointer(struct kmem_cache *s,
  225. struct page *page, const void *object)
  226. {
  227. void *base;
  228. if (!object)
  229. return 1;
  230. base = page_address(page);
  231. if (object < base || object >= base + page->objects * s->size ||
  232. (object - base) % s->size) {
  233. return 0;
  234. }
  235. return 1;
  236. }
  237. static inline void *get_freepointer(struct kmem_cache *s, void *object)
  238. {
  239. return *(void **)(object + s->offset);
  240. }
  241. static void prefetch_freepointer(const struct kmem_cache *s, void *object)
  242. {
  243. prefetch(object + s->offset);
  244. }
  245. static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
  246. {
  247. void *p;
  248. #ifdef CONFIG_DEBUG_PAGEALLOC
  249. probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
  250. #else
  251. p = get_freepointer(s, object);
  252. #endif
  253. return p;
  254. }
  255. static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
  256. {
  257. *(void **)(object + s->offset) = fp;
  258. }
  259. /* Loop over all objects in a slab */
  260. #define for_each_object(__p, __s, __addr, __objects) \
  261. for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
  262. __p += (__s)->size)
  263. /* Determine object index from a given position */
  264. static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
  265. {
  266. return (p - addr) / s->size;
  267. }
  268. static inline size_t slab_ksize(const struct kmem_cache *s)
  269. {
  270. #ifdef CONFIG_SLUB_DEBUG
  271. /*
  272. * Debugging requires use of the padding between object
  273. * and whatever may come after it.
  274. */
  275. if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
  276. return s->objsize;
  277. #endif
  278. /*
  279. * If we have the need to store the freelist pointer
  280. * back there or track user information then we can
  281. * only use the space before that information.
  282. */
  283. if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
  284. return s->inuse;
  285. /*
  286. * Else we can use all the padding etc for the allocation
  287. */
  288. return s->size;
  289. }
  290. static inline int order_objects(int order, unsigned long size, int reserved)
  291. {
  292. return ((PAGE_SIZE << order) - reserved) / size;
  293. }
  294. static inline struct kmem_cache_order_objects oo_make(int order,
  295. unsigned long size, int reserved)
  296. {
  297. struct kmem_cache_order_objects x = {
  298. (order << OO_SHIFT) + order_objects(order, size, reserved)
  299. };
  300. return x;
  301. }
  302. static inline int oo_order(struct kmem_cache_order_objects x)
  303. {
  304. return x.x >> OO_SHIFT;
  305. }
  306. static inline int oo_objects(struct kmem_cache_order_objects x)
  307. {
  308. return x.x & OO_MASK;
  309. }
  310. /*
  311. * Per slab locking using the pagelock
  312. */
  313. static __always_inline void slab_lock(struct page *page)
  314. {
  315. bit_spin_lock(PG_locked, &page->flags);
  316. }
  317. static __always_inline void slab_unlock(struct page *page)
  318. {
  319. __bit_spin_unlock(PG_locked, &page->flags);
  320. }
  321. /* Interrupts must be disabled (for the fallback code to work right) */
  322. static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
  323. void *freelist_old, unsigned long counters_old,
  324. void *freelist_new, unsigned long counters_new,
  325. const char *n)
  326. {
  327. VM_BUG_ON(!irqs_disabled());
  328. #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
  329. defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
  330. if (s->flags & __CMPXCHG_DOUBLE) {
  331. if (cmpxchg_double(&page->freelist, &page->counters,
  332. freelist_old, counters_old,
  333. freelist_new, counters_new))
  334. return 1;
  335. } else
  336. #endif
  337. {
  338. slab_lock(page);
  339. if (page->freelist == freelist_old && page->counters == counters_old) {
  340. page->freelist = freelist_new;
  341. page->counters = counters_new;
  342. slab_unlock(page);
  343. return 1;
  344. }
  345. slab_unlock(page);
  346. }
  347. cpu_relax();
  348. stat(s, CMPXCHG_DOUBLE_FAIL);
  349. #ifdef SLUB_DEBUG_CMPXCHG
  350. printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
  351. #endif
  352. return 0;
  353. }
  354. static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
  355. void *freelist_old, unsigned long counters_old,
  356. void *freelist_new, unsigned long counters_new,
  357. const char *n)
  358. {
  359. #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
  360. defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
  361. if (s->flags & __CMPXCHG_DOUBLE) {
  362. if (cmpxchg_double(&page->freelist, &page->counters,
  363. freelist_old, counters_old,
  364. freelist_new, counters_new))
  365. return 1;
  366. } else
  367. #endif
  368. {
  369. unsigned long flags;
  370. local_irq_save(flags);
  371. slab_lock(page);
  372. if (page->freelist == freelist_old && page->counters == counters_old) {
  373. page->freelist = freelist_new;
  374. page->counters = counters_new;
  375. slab_unlock(page);
  376. local_irq_restore(flags);
  377. return 1;
  378. }
  379. slab_unlock(page);
  380. local_irq_restore(flags);
  381. }
  382. cpu_relax();
  383. stat(s, CMPXCHG_DOUBLE_FAIL);
  384. #ifdef SLUB_DEBUG_CMPXCHG
  385. printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
  386. #endif
  387. return 0;
  388. }
  389. #ifdef CONFIG_SLUB_DEBUG
  390. /*
  391. * Determine a map of object in use on a page.
  392. *
  393. * Node listlock must be held to guarantee that the page does
  394. * not vanish from under us.
  395. */
  396. static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
  397. {
  398. void *p;
  399. void *addr = page_address(page);
  400. for (p = page->freelist; p; p = get_freepointer(s, p))
  401. set_bit(slab_index(p, s, addr), map);
  402. }
  403. /*
  404. * Debug settings:
  405. */
  406. #ifdef CONFIG_SLUB_DEBUG_ON
  407. static int slub_debug = DEBUG_DEFAULT_FLAGS;
  408. #else
  409. static int slub_debug;
  410. #endif
  411. static char *slub_debug_slabs;
  412. static int disable_higher_order_debug;
  413. /*
  414. * Object debugging
  415. */
  416. static void print_section(char *text, u8 *addr, unsigned int length)
  417. {
  418. print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
  419. length, 1);
  420. }
  421. static struct track *get_track(struct kmem_cache *s, void *object,
  422. enum track_item alloc)
  423. {
  424. struct track *p;
  425. if (s->offset)
  426. p = object + s->offset + sizeof(void *);
  427. else
  428. p = object + s->inuse;
  429. return p + alloc;
  430. }
  431. static void set_track(struct kmem_cache *s, void *object,
  432. enum track_item alloc, unsigned long addr)
  433. {
  434. struct track *p = get_track(s, object, alloc);
  435. if (addr) {
  436. #ifdef CONFIG_STACKTRACE
  437. struct stack_trace trace;
  438. int i;
  439. trace.nr_entries = 0;
  440. trace.max_entries = TRACK_ADDRS_COUNT;
  441. trace.entries = p->addrs;
  442. trace.skip = 3;
  443. save_stack_trace(&trace);
  444. /* See rant in lockdep.c */
  445. if (trace.nr_entries != 0 &&
  446. trace.entries[trace.nr_entries - 1] == ULONG_MAX)
  447. trace.nr_entries--;
  448. for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
  449. p->addrs[i] = 0;
  450. #endif
  451. p->addr = addr;
  452. p->cpu = smp_processor_id();
  453. p->pid = current->pid;
  454. p->when = jiffies;
  455. } else
  456. memset(p, 0, sizeof(struct track));
  457. }
  458. static void init_tracking(struct kmem_cache *s, void *object)
  459. {
  460. if (!(s->flags & SLAB_STORE_USER))
  461. return;
  462. set_track(s, object, TRACK_FREE, 0UL);
  463. set_track(s, object, TRACK_ALLOC, 0UL);
  464. }
  465. static void print_track(const char *s, struct track *t)
  466. {
  467. if (!t->addr)
  468. return;
  469. printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
  470. s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
  471. #ifdef CONFIG_STACKTRACE
  472. {
  473. int i;
  474. for (i = 0; i < TRACK_ADDRS_COUNT; i++)
  475. if (t->addrs[i])
  476. printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
  477. else
  478. break;
  479. }
  480. #endif
  481. }
  482. static void print_tracking(struct kmem_cache *s, void *object)
  483. {
  484. if (!(s->flags & SLAB_STORE_USER))
  485. return;
  486. print_track("Allocated", get_track(s, object, TRACK_ALLOC));
  487. print_track("Freed", get_track(s, object, TRACK_FREE));
  488. }
  489. static void print_page_info(struct page *page)
  490. {
  491. printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
  492. page, page->objects, page->inuse, page->freelist, page->flags);
  493. }
  494. static void slab_bug(struct kmem_cache *s, char *fmt, ...)
  495. {
  496. va_list args;
  497. char buf[100];
  498. va_start(args, fmt);
  499. vsnprintf(buf, sizeof(buf), fmt, args);
  500. va_end(args);
  501. printk(KERN_ERR "========================================"
  502. "=====================================\n");
  503. printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
  504. printk(KERN_ERR "----------------------------------------"
  505. "-------------------------------------\n\n");
  506. }
  507. static void slab_fix(struct kmem_cache *s, char *fmt, ...)
  508. {
  509. va_list args;
  510. char buf[100];
  511. va_start(args, fmt);
  512. vsnprintf(buf, sizeof(buf), fmt, args);
  513. va_end(args);
  514. printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
  515. }
  516. static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
  517. {
  518. unsigned int off; /* Offset of last byte */
  519. u8 *addr = page_address(page);
  520. print_tracking(s, p);
  521. print_page_info(page);
  522. printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
  523. p, p - addr, get_freepointer(s, p));
  524. if (p > addr + 16)
  525. print_section("Bytes b4 ", p - 16, 16);
  526. print_section("Object ", p, min_t(unsigned long, s->objsize,
  527. PAGE_SIZE));
  528. if (s->flags & SLAB_RED_ZONE)
  529. print_section("Redzone ", p + s->objsize,
  530. s->inuse - s->objsize);
  531. if (s->offset)
  532. off = s->offset + sizeof(void *);
  533. else
  534. off = s->inuse;
  535. if (s->flags & SLAB_STORE_USER)
  536. off += 2 * sizeof(struct track);
  537. if (off != s->size)
  538. /* Beginning of the filler is the free pointer */
  539. print_section("Padding ", p + off, s->size - off);
  540. dump_stack();
  541. }
  542. static void object_err(struct kmem_cache *s, struct page *page,
  543. u8 *object, char *reason)
  544. {
  545. slab_bug(s, "%s", reason);
  546. print_trailer(s, page, object);
  547. }
  548. static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
  549. {
  550. va_list args;
  551. char buf[100];
  552. va_start(args, fmt);
  553. vsnprintf(buf, sizeof(buf), fmt, args);
  554. va_end(args);
  555. slab_bug(s, "%s", buf);
  556. print_page_info(page);
  557. dump_stack();
  558. }
  559. static void init_object(struct kmem_cache *s, void *object, u8 val)
  560. {
  561. u8 *p = object;
  562. if (s->flags & __OBJECT_POISON) {
  563. memset(p, POISON_FREE, s->objsize - 1);
  564. p[s->objsize - 1] = POISON_END;
  565. }
  566. if (s->flags & SLAB_RED_ZONE)
  567. memset(p + s->objsize, val, s->inuse - s->objsize);
  568. }
  569. static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
  570. void *from, void *to)
  571. {
  572. slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
  573. memset(from, data, to - from);
  574. }
  575. static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
  576. u8 *object, char *what,
  577. u8 *start, unsigned int value, unsigned int bytes)
  578. {
  579. u8 *fault;
  580. u8 *end;
  581. fault = memchr_inv(start, value, bytes);
  582. if (!fault)
  583. return 1;
  584. end = start + bytes;
  585. while (end > fault && end[-1] == value)
  586. end--;
  587. slab_bug(s, "%s overwritten", what);
  588. printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
  589. fault, end - 1, fault[0], value);
  590. print_trailer(s, page, object);
  591. restore_bytes(s, what, value, fault, end);
  592. return 0;
  593. }
  594. /*
  595. * Object layout:
  596. *
  597. * object address
  598. * Bytes of the object to be managed.
  599. * If the freepointer may overlay the object then the free
  600. * pointer is the first word of the object.
  601. *
  602. * Poisoning uses 0x6b (POISON_FREE) and the last byte is
  603. * 0xa5 (POISON_END)
  604. *
  605. * object + s->objsize
  606. * Padding to reach word boundary. This is also used for Redzoning.
  607. * Padding is extended by another word if Redzoning is enabled and
  608. * objsize == inuse.
  609. *
  610. * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
  611. * 0xcc (RED_ACTIVE) for objects in use.
  612. *
  613. * object + s->inuse
  614. * Meta data starts here.
  615. *
  616. * A. Free pointer (if we cannot overwrite object on free)
  617. * B. Tracking data for SLAB_STORE_USER
  618. * C. Padding to reach required alignment boundary or at mininum
  619. * one word if debugging is on to be able to detect writes
  620. * before the word boundary.
  621. *
  622. * Padding is done using 0x5a (POISON_INUSE)
  623. *
  624. * object + s->size
  625. * Nothing is used beyond s->size.
  626. *
  627. * If slabcaches are merged then the objsize and inuse boundaries are mostly
  628. * ignored. And therefore no slab options that rely on these boundaries
  629. * may be used with merged slabcaches.
  630. */
  631. static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
  632. {
  633. unsigned long off = s->inuse; /* The end of info */
  634. if (s->offset)
  635. /* Freepointer is placed after the object. */
  636. off += sizeof(void *);
  637. if (s->flags & SLAB_STORE_USER)
  638. /* We also have user information there */
  639. off += 2 * sizeof(struct track);
  640. if (s->size == off)
  641. return 1;
  642. return check_bytes_and_report(s, page, p, "Object padding",
  643. p + off, POISON_INUSE, s->size - off);
  644. }
  645. /* Check the pad bytes at the end of a slab page */
  646. static int slab_pad_check(struct kmem_cache *s, struct page *page)
  647. {
  648. u8 *start;
  649. u8 *fault;
  650. u8 *end;
  651. int length;
  652. int remainder;
  653. if (!(s->flags & SLAB_POISON))
  654. return 1;
  655. start = page_address(page);
  656. length = (PAGE_SIZE << compound_order(page)) - s->reserved;
  657. end = start + length;
  658. remainder = length % s->size;
  659. if (!remainder)
  660. return 1;
  661. fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
  662. if (!fault)
  663. return 1;
  664. while (end > fault && end[-1] == POISON_INUSE)
  665. end--;
  666. slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
  667. print_section("Padding ", end - remainder, remainder);
  668. restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
  669. return 0;
  670. }
  671. static int check_object(struct kmem_cache *s, struct page *page,
  672. void *object, u8 val)
  673. {
  674. u8 *p = object;
  675. u8 *endobject = object + s->objsize;
  676. if (s->flags & SLAB_RED_ZONE) {
  677. if (!check_bytes_and_report(s, page, object, "Redzone",
  678. endobject, val, s->inuse - s->objsize))
  679. return 0;
  680. } else {
  681. if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
  682. check_bytes_and_report(s, page, p, "Alignment padding",
  683. endobject, POISON_INUSE, s->inuse - s->objsize);
  684. }
  685. }
  686. if (s->flags & SLAB_POISON) {
  687. if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
  688. (!check_bytes_and_report(s, page, p, "Poison", p,
  689. POISON_FREE, s->objsize - 1) ||
  690. !check_bytes_and_report(s, page, p, "Poison",
  691. p + s->objsize - 1, POISON_END, 1)))
  692. return 0;
  693. /*
  694. * check_pad_bytes cleans up on its own.
  695. */
  696. check_pad_bytes(s, page, p);
  697. }
  698. if (!s->offset && val == SLUB_RED_ACTIVE)
  699. /*
  700. * Object and freepointer overlap. Cannot check
  701. * freepointer while object is allocated.
  702. */
  703. return 1;
  704. /* Check free pointer validity */
  705. if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
  706. object_err(s, page, p, "Freepointer corrupt");
  707. /*
  708. * No choice but to zap it and thus lose the remainder
  709. * of the free objects in this slab. May cause
  710. * another error because the object count is now wrong.
  711. */
  712. set_freepointer(s, p, NULL);
  713. return 0;
  714. }
  715. return 1;
  716. }
  717. static int check_slab(struct kmem_cache *s, struct page *page)
  718. {
  719. int maxobj;
  720. VM_BUG_ON(!irqs_disabled());
  721. if (!PageSlab(page)) {
  722. slab_err(s, page, "Not a valid slab page");
  723. return 0;
  724. }
  725. maxobj = order_objects(compound_order(page), s->size, s->reserved);
  726. if (page->objects > maxobj) {
  727. slab_err(s, page, "objects %u > max %u",
  728. s->name, page->objects, maxobj);
  729. return 0;
  730. }
  731. if (page->inuse > page->objects) {
  732. slab_err(s, page, "inuse %u > max %u",
  733. s->name, page->inuse, page->objects);
  734. return 0;
  735. }
  736. /* Slab_pad_check fixes things up after itself */
  737. slab_pad_check(s, page);
  738. return 1;
  739. }
  740. /*
  741. * Determine if a certain object on a page is on the freelist. Must hold the
  742. * slab lock to guarantee that the chains are in a consistent state.
  743. */
  744. static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
  745. {
  746. int nr = 0;
  747. void *fp;
  748. void *object = NULL;
  749. unsigned long max_objects;
  750. fp = page->freelist;
  751. while (fp && nr <= page->objects) {
  752. if (fp == search)
  753. return 1;
  754. if (!check_valid_pointer(s, page, fp)) {
  755. if (object) {
  756. object_err(s, page, object,
  757. "Freechain corrupt");
  758. set_freepointer(s, object, NULL);
  759. break;
  760. } else {
  761. slab_err(s, page, "Freepointer corrupt");
  762. page->freelist = NULL;
  763. page->inuse = page->objects;
  764. slab_fix(s, "Freelist cleared");
  765. return 0;
  766. }
  767. break;
  768. }
  769. object = fp;
  770. fp = get_freepointer(s, object);
  771. nr++;
  772. }
  773. max_objects = order_objects(compound_order(page), s->size, s->reserved);
  774. if (max_objects > MAX_OBJS_PER_PAGE)
  775. max_objects = MAX_OBJS_PER_PAGE;
  776. if (page->objects != max_objects) {
  777. slab_err(s, page, "Wrong number of objects. Found %d but "
  778. "should be %d", page->objects, max_objects);
  779. page->objects = max_objects;
  780. slab_fix(s, "Number of objects adjusted.");
  781. }
  782. if (page->inuse != page->objects - nr) {
  783. slab_err(s, page, "Wrong object count. Counter is %d but "
  784. "counted were %d", page->inuse, page->objects - nr);
  785. page->inuse = page->objects - nr;
  786. slab_fix(s, "Object count adjusted.");
  787. }
  788. return search == NULL;
  789. }
  790. static void trace(struct kmem_cache *s, struct page *page, void *object,
  791. int alloc)
  792. {
  793. if (s->flags & SLAB_TRACE) {
  794. printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
  795. s->name,
  796. alloc ? "alloc" : "free",
  797. object, page->inuse,
  798. page->freelist);
  799. if (!alloc)
  800. print_section("Object ", (void *)object, s->objsize);
  801. dump_stack();
  802. }
  803. }
  804. /*
  805. * Hooks for other subsystems that check memory allocations. In a typical
  806. * production configuration these hooks all should produce no code at all.
  807. */
  808. static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
  809. {
  810. flags &= gfp_allowed_mask;
  811. lockdep_trace_alloc(flags);
  812. might_sleep_if(flags & __GFP_WAIT);
  813. return should_failslab(s->objsize, flags, s->flags);
  814. }
  815. static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
  816. {
  817. flags &= gfp_allowed_mask;
  818. kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
  819. kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
  820. }
  821. static inline void slab_free_hook(struct kmem_cache *s, void *x)
  822. {
  823. kmemleak_free_recursive(x, s->flags);
  824. /*
  825. * Trouble is that we may no longer disable interupts in the fast path
  826. * So in order to make the debug calls that expect irqs to be
  827. * disabled we need to disable interrupts temporarily.
  828. */
  829. #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
  830. {
  831. unsigned long flags;
  832. local_irq_save(flags);
  833. kmemcheck_slab_free(s, x, s->objsize);
  834. debug_check_no_locks_freed(x, s->objsize);
  835. local_irq_restore(flags);
  836. }
  837. #endif
  838. if (!(s->flags & SLAB_DEBUG_OBJECTS))
  839. debug_check_no_obj_freed(x, s->objsize);
  840. }
  841. /*
  842. * Tracking of fully allocated slabs for debugging purposes.
  843. *
  844. * list_lock must be held.
  845. */
  846. static void add_full(struct kmem_cache *s,
  847. struct kmem_cache_node *n, struct page *page)
  848. {
  849. if (!(s->flags & SLAB_STORE_USER))
  850. return;
  851. list_add(&page->lru, &n->full);
  852. }
  853. /*
  854. * list_lock must be held.
  855. */
  856. static void remove_full(struct kmem_cache *s, struct page *page)
  857. {
  858. if (!(s->flags & SLAB_STORE_USER))
  859. return;
  860. list_del(&page->lru);
  861. }
  862. /* Tracking of the number of slabs for debugging purposes */
  863. static inline unsigned long slabs_node(struct kmem_cache *s, int node)
  864. {
  865. struct kmem_cache_node *n = get_node(s, node);
  866. return atomic_long_read(&n->nr_slabs);
  867. }
  868. static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
  869. {
  870. return atomic_long_read(&n->nr_slabs);
  871. }
  872. static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
  873. {
  874. struct kmem_cache_node *n = get_node(s, node);
  875. /*
  876. * May be called early in order to allocate a slab for the
  877. * kmem_cache_node structure. Solve the chicken-egg
  878. * dilemma by deferring the increment of the count during
  879. * bootstrap (see early_kmem_cache_node_alloc).
  880. */
  881. if (n) {
  882. atomic_long_inc(&n->nr_slabs);
  883. atomic_long_add(objects, &n->total_objects);
  884. }
  885. }
  886. static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
  887. {
  888. struct kmem_cache_node *n = get_node(s, node);
  889. atomic_long_dec(&n->nr_slabs);
  890. atomic_long_sub(objects, &n->total_objects);
  891. }
  892. /* Object debug checks for alloc/free paths */
  893. static void setup_object_debug(struct kmem_cache *s, struct page *page,
  894. void *object)
  895. {
  896. if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
  897. return;
  898. init_object(s, object, SLUB_RED_INACTIVE);
  899. init_tracking(s, object);
  900. }
  901. static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
  902. void *object, unsigned long addr)
  903. {
  904. if (!check_slab(s, page))
  905. goto bad;
  906. if (!check_valid_pointer(s, page, object)) {
  907. object_err(s, page, object, "Freelist Pointer check fails");
  908. goto bad;
  909. }
  910. if (!check_object(s, page, object, SLUB_RED_INACTIVE))
  911. goto bad;
  912. /* Success perform special debug activities for allocs */
  913. if (s->flags & SLAB_STORE_USER)
  914. set_track(s, object, TRACK_ALLOC, addr);
  915. trace(s, page, object, 1);
  916. init_object(s, object, SLUB_RED_ACTIVE);
  917. return 1;
  918. bad:
  919. if (PageSlab(page)) {
  920. /*
  921. * If this is a slab page then lets do the best we can
  922. * to avoid issues in the future. Marking all objects
  923. * as used avoids touching the remaining objects.
  924. */
  925. slab_fix(s, "Marking all objects used");
  926. page->inuse = page->objects;
  927. page->freelist = NULL;
  928. }
  929. return 0;
  930. }
  931. static noinline int free_debug_processing(struct kmem_cache *s,
  932. struct page *page, void *object, unsigned long addr)
  933. {
  934. unsigned long flags;
  935. int rc = 0;
  936. local_irq_save(flags);
  937. slab_lock(page);
  938. if (!check_slab(s, page))
  939. goto fail;
  940. if (!check_valid_pointer(s, page, object)) {
  941. slab_err(s, page, "Invalid object pointer 0x%p", object);
  942. goto fail;
  943. }
  944. if (on_freelist(s, page, object)) {
  945. object_err(s, page, object, "Object already free");
  946. goto fail;
  947. }
  948. if (!check_object(s, page, object, SLUB_RED_ACTIVE))
  949. goto out;
  950. if (unlikely(s != page->slab)) {
  951. if (!PageSlab(page)) {
  952. slab_err(s, page, "Attempt to free object(0x%p) "
  953. "outside of slab", object);
  954. } else if (!page->slab) {
  955. printk(KERN_ERR
  956. "SLUB <none>: no slab for object 0x%p.\n",
  957. object);
  958. dump_stack();
  959. } else
  960. object_err(s, page, object,
  961. "page slab pointer corrupt.");
  962. goto fail;
  963. }
  964. if (s->flags & SLAB_STORE_USER)
  965. set_track(s, object, TRACK_FREE, addr);
  966. trace(s, page, object, 0);
  967. init_object(s, object, SLUB_RED_INACTIVE);
  968. rc = 1;
  969. out:
  970. slab_unlock(page);
  971. local_irq_restore(flags);
  972. return rc;
  973. fail:
  974. slab_fix(s, "Object at 0x%p not freed", object);
  975. goto out;
  976. }
  977. static int __init setup_slub_debug(char *str)
  978. {
  979. slub_debug = DEBUG_DEFAULT_FLAGS;
  980. if (*str++ != '=' || !*str)
  981. /*
  982. * No options specified. Switch on full debugging.
  983. */
  984. goto out;
  985. if (*str == ',')
  986. /*
  987. * No options but restriction on slabs. This means full
  988. * debugging for slabs matching a pattern.
  989. */
  990. goto check_slabs;
  991. if (tolower(*str) == 'o') {
  992. /*
  993. * Avoid enabling debugging on caches if its minimum order
  994. * would increase as a result.
  995. */
  996. disable_higher_order_debug = 1;
  997. goto out;
  998. }
  999. slub_debug = 0;
  1000. if (*str == '-')
  1001. /*
  1002. * Switch off all debugging measures.
  1003. */
  1004. goto out;
  1005. /*
  1006. * Determine which debug features should be switched on
  1007. */
  1008. for (; *str && *str != ','; str++) {
  1009. switch (tolower(*str)) {
  1010. case 'f':
  1011. slub_debug |= SLAB_DEBUG_FREE;
  1012. break;
  1013. case 'z':
  1014. slub_debug |= SLAB_RED_ZONE;
  1015. break;
  1016. case 'p':
  1017. slub_debug |= SLAB_POISON;
  1018. break;
  1019. case 'u':
  1020. slub_debug |= SLAB_STORE_USER;
  1021. break;
  1022. case 't':
  1023. slub_debug |= SLAB_TRACE;
  1024. break;
  1025. case 'a':
  1026. slub_debug |= SLAB_FAILSLAB;
  1027. break;
  1028. default:
  1029. printk(KERN_ERR "slub_debug option '%c' "
  1030. "unknown. skipped\n", *str);
  1031. }
  1032. }
  1033. check_slabs:
  1034. if (*str == ',')
  1035. slub_debug_slabs = str + 1;
  1036. out:
  1037. return 1;
  1038. }
  1039. __setup("slub_debug", setup_slub_debug);
  1040. static unsigned long kmem_cache_flags(unsigned long objsize,
  1041. unsigned long flags, const char *name,
  1042. void (*ctor)(void *))
  1043. {
  1044. /*
  1045. * Enable debugging if selected on the kernel commandline.
  1046. */
  1047. if (slub_debug && (!slub_debug_slabs ||
  1048. !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
  1049. flags |= slub_debug;
  1050. return flags;
  1051. }
  1052. #else
  1053. static inline void setup_object_debug(struct kmem_cache *s,
  1054. struct page *page, void *object) {}
  1055. static inline int alloc_debug_processing(struct kmem_cache *s,
  1056. struct page *page, void *object, unsigned long addr) { return 0; }
  1057. static inline int free_debug_processing(struct kmem_cache *s,
  1058. struct page *page, void *object, unsigned long addr) { return 0; }
  1059. static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
  1060. { return 1; }
  1061. static inline int check_object(struct kmem_cache *s, struct page *page,
  1062. void *object, u8 val) { return 1; }
  1063. static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
  1064. struct page *page) {}
  1065. static inline void remove_full(struct kmem_cache *s, struct page *page) {}
  1066. static inline unsigned long kmem_cache_flags(unsigned long objsize,
  1067. unsigned long flags, const char *name,
  1068. void (*ctor)(void *))
  1069. {
  1070. return flags;
  1071. }
  1072. #define slub_debug 0
  1073. #define disable_higher_order_debug 0
  1074. static inline unsigned long slabs_node(struct kmem_cache *s, int node)
  1075. { return 0; }
  1076. static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
  1077. { return 0; }
  1078. static inline void inc_slabs_node(struct kmem_cache *s, int node,
  1079. int objects) {}
  1080. static inline void dec_slabs_node(struct kmem_cache *s, int node,
  1081. int objects) {}
  1082. static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
  1083. { return 0; }
  1084. static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
  1085. void *object) {}
  1086. static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
  1087. #endif /* CONFIG_SLUB_DEBUG */
  1088. /*
  1089. * Slab allocation and freeing
  1090. */
  1091. static inline struct page *alloc_slab_page(gfp_t flags, int node,
  1092. struct kmem_cache_order_objects oo)
  1093. {
  1094. int order = oo_order(oo);
  1095. flags |= __GFP_NOTRACK;
  1096. if (node == NUMA_NO_NODE)
  1097. return alloc_pages(flags, order);
  1098. else
  1099. return alloc_pages_exact_node(node, flags, order);
  1100. }
  1101. static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
  1102. {
  1103. struct page *page;
  1104. struct kmem_cache_order_objects oo = s->oo;
  1105. gfp_t alloc_gfp;
  1106. flags &= gfp_allowed_mask;
  1107. if (flags & __GFP_WAIT)
  1108. local_irq_enable();
  1109. flags |= s->allocflags;
  1110. /*
  1111. * Let the initial higher-order allocation fail under memory pressure
  1112. * so we fall-back to the minimum order allocation.
  1113. */
  1114. alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
  1115. page = alloc_slab_page(alloc_gfp, node, oo);
  1116. if (unlikely(!page)) {
  1117. oo = s->min;
  1118. /*
  1119. * Allocation may have failed due to fragmentation.
  1120. * Try a lower order alloc if possible
  1121. */
  1122. page = alloc_slab_page(flags, node, oo);
  1123. if (page)
  1124. stat(s, ORDER_FALLBACK);
  1125. }
  1126. if (flags & __GFP_WAIT)
  1127. local_irq_disable();
  1128. if (!page)
  1129. return NULL;
  1130. if (kmemcheck_enabled
  1131. && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
  1132. int pages = 1 << oo_order(oo);
  1133. kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
  1134. /*
  1135. * Objects from caches that have a constructor don't get
  1136. * cleared when they're allocated, so we need to do it here.
  1137. */
  1138. if (s->ctor)
  1139. kmemcheck_mark_uninitialized_pages(page, pages);
  1140. else
  1141. kmemcheck_mark_unallocated_pages(page, pages);
  1142. }
  1143. page->objects = oo_objects(oo);
  1144. mod_zone_page_state(page_zone(page),
  1145. (s->flags & SLAB_RECLAIM_ACCOUNT) ?
  1146. NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
  1147. 1 << oo_order(oo));
  1148. return page;
  1149. }
  1150. static void setup_object(struct kmem_cache *s, struct page *page,
  1151. void *object)
  1152. {
  1153. setup_object_debug(s, page, object);
  1154. if (unlikely(s->ctor))
  1155. s->ctor(object);
  1156. }
  1157. static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
  1158. {
  1159. struct page *page;
  1160. void *start;
  1161. void *last;
  1162. void *p;
  1163. BUG_ON(flags & GFP_SLAB_BUG_MASK);
  1164. page = allocate_slab(s,
  1165. flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
  1166. if (!page)
  1167. goto out;
  1168. inc_slabs_node(s, page_to_nid(page), page->objects);
  1169. page->slab = s;
  1170. page->flags |= 1 << PG_slab;
  1171. start = page_address(page);
  1172. if (unlikely(s->flags & SLAB_POISON))
  1173. memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
  1174. last = start;
  1175. for_each_object(p, s, start, page->objects) {
  1176. setup_object(s, page, last);
  1177. set_freepointer(s, last, p);
  1178. last = p;
  1179. }
  1180. setup_object(s, page, last);
  1181. set_freepointer(s, last, NULL);
  1182. #ifdef CONFIG_TIMA_RKP_30
  1183. tima_send_cmd3(page_to_phys(page), compound_order(page), 1, 0x26);
  1184. #endif
  1185. page->freelist = start;
  1186. page->inuse = page->objects;
  1187. page->frozen = 1;
  1188. out:
  1189. return page;
  1190. }
  1191. static void __free_slab(struct kmem_cache *s, struct page *page)
  1192. {
  1193. int order = compound_order(page);
  1194. int pages = 1 << order;
  1195. if (kmem_cache_debug(s)) {
  1196. void *p;
  1197. slab_pad_check(s, page);
  1198. for_each_object(p, s, page_address(page),
  1199. page->objects)
  1200. check_object(s, page, p, SLUB_RED_INACTIVE);
  1201. }
  1202. kmemcheck_free_shadow(page, compound_order(page));
  1203. mod_zone_page_state(page_zone(page),
  1204. (s->flags & SLAB_RECLAIM_ACCOUNT) ?
  1205. NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
  1206. -pages);
  1207. __ClearPageSlab(page);
  1208. reset_page_mapcount(page);
  1209. if (current->reclaim_state)
  1210. current->reclaim_state->reclaimed_slab += pages;
  1211. __free_pages(page, order);
  1212. }
  1213. #define need_reserve_slab_rcu \
  1214. (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
  1215. static void rcu_free_slab(struct rcu_head *h)
  1216. {
  1217. struct page *page;
  1218. if (need_reserve_slab_rcu)
  1219. page = virt_to_head_page(h);
  1220. else
  1221. page = container_of((struct list_head *)h, struct page, lru);
  1222. __free_slab(page->slab, page);
  1223. }
  1224. static void free_slab(struct kmem_cache *s, struct page *page)
  1225. {
  1226. #ifdef CONFIG_TIMA_RKP_30
  1227. tima_send_cmd3(page_to_phys(page), compound_order(page), 0, 0x26);
  1228. #endif
  1229. if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
  1230. struct rcu_head *head;
  1231. if (need_reserve_slab_rcu) {
  1232. int order = compound_order(page);
  1233. int offset = (PAGE_SIZE << order) - s->reserved;
  1234. VM_BUG_ON(s->reserved != sizeof(*head));
  1235. head = page_address(page) + offset;
  1236. } else {
  1237. /*
  1238. * RCU free overloads the RCU head over the LRU
  1239. */
  1240. head = (void *)&page->lru;
  1241. }
  1242. call_rcu(head, rcu_free_slab);
  1243. } else
  1244. __free_slab(s, page);
  1245. }
  1246. static void discard_slab(struct kmem_cache *s, struct page *page)
  1247. {
  1248. dec_slabs_node(s, page_to_nid(page), page->objects);
  1249. free_slab(s, page);
  1250. }
  1251. /*
  1252. * Management of partially allocated slabs.
  1253. *
  1254. * list_lock must be held.
  1255. */
  1256. static inline void add_partial(struct kmem_cache_node *n,
  1257. struct page *page, int tail)
  1258. {
  1259. n->nr_partial++;
  1260. if (tail == DEACTIVATE_TO_TAIL)
  1261. list_add_tail(&page->lru, &n->partial);
  1262. else
  1263. list_add(&page->lru, &n->partial);
  1264. }
  1265. /*
  1266. * list_lock must be held.
  1267. */
  1268. static inline void remove_partial(struct kmem_cache_node *n,
  1269. struct page *page)
  1270. {
  1271. list_del(&page->lru);
  1272. n->nr_partial--;
  1273. }
  1274. /*
  1275. * Lock slab, remove from the partial list and put the object into the
  1276. * per cpu freelist.
  1277. *
  1278. * Returns a list of objects or NULL if it fails.
  1279. *
  1280. * Must hold list_lock.
  1281. */
  1282. static inline void *acquire_slab(struct kmem_cache *s,
  1283. struct kmem_cache_node *n, struct page *page,
  1284. int mode)
  1285. {
  1286. void *freelist;
  1287. unsigned long counters;
  1288. struct page new;
  1289. /*
  1290. * Zap the freelist and set the frozen bit.
  1291. * The old freelist is the list of objects for the
  1292. * per cpu allocation list.
  1293. */
  1294. do {
  1295. freelist = page->freelist;
  1296. counters = page->counters;
  1297. new.counters = counters;
  1298. if (mode) {
  1299. new.inuse = page->objects;
  1300. new.freelist = NULL;
  1301. } else {
  1302. new.freelist = freelist;
  1303. }
  1304. VM_BUG_ON(new.frozen);
  1305. new.frozen = 1;
  1306. } while (!__cmpxchg_double_slab(s, page,
  1307. freelist, counters,
  1308. new.freelist, new.counters,
  1309. "lock and freeze"));
  1310. remove_partial(n, page);
  1311. return freelist;
  1312. }
  1313. static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
  1314. /*
  1315. * Try to allocate a partial slab from a specific node.
  1316. */
  1317. static void *get_partial_node(struct kmem_cache *s,
  1318. struct kmem_cache_node *n, struct kmem_cache_cpu *c)
  1319. {
  1320. struct page *page, *page2;
  1321. void *object = NULL;
  1322. /*
  1323. * Racy check. If we mistakenly see no partial slabs then we
  1324. * just allocate an empty slab. If we mistakenly try to get a
  1325. * partial slab and there is none available then get_partials()
  1326. * will return NULL.
  1327. */
  1328. if (!n || !n->nr_partial)
  1329. return NULL;
  1330. spin_lock(&n->list_lock);
  1331. list_for_each_entry_safe(page, page2, &n->partial, lru) {
  1332. void *t = acquire_slab(s, n, page, object == NULL);
  1333. int available;
  1334. if (!t)
  1335. break;
  1336. if (!object) {
  1337. c->page = page;
  1338. c->node = page_to_nid(page);
  1339. stat(s, ALLOC_FROM_PARTIAL);
  1340. object = t;
  1341. available = page->objects - page->inuse;
  1342. } else {
  1343. available = put_cpu_partial(s, page, 0);
  1344. stat(s, CPU_PARTIAL_NODE);
  1345. }
  1346. if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
  1347. break;
  1348. }
  1349. spin_unlock(&n->list_lock);
  1350. return object;
  1351. }
  1352. /*
  1353. * Get a page from somewhere. Search in increasing NUMA distances.
  1354. */
  1355. static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags,
  1356. struct kmem_cache_cpu *c)
  1357. {
  1358. #ifdef CONFIG_NUMA
  1359. struct zonelist *zonelist;
  1360. struct zoneref *z;
  1361. struct zone *zone;
  1362. enum zone_type high_zoneidx = gfp_zone(flags);
  1363. void *object;
  1364. unsigned int cpuset_mems_cookie;
  1365. /*
  1366. * The defrag ratio allows a configuration of the tradeoffs between
  1367. * inter node defragmentation and node local allocations. A lower
  1368. * defrag_ratio increases the tendency to do local allocations
  1369. * instead of attempting to obtain partial slabs from other nodes.
  1370. *
  1371. * If the defrag_ratio is set to 0 then kmalloc() always
  1372. * returns node local objects. If the ratio is higher then kmalloc()
  1373. * may return off node objects because partial slabs are obtained
  1374. * from other nodes and filled up.
  1375. *
  1376. * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
  1377. * defrag_ratio = 1000) then every (well almost) allocation will
  1378. * first attempt to defrag slab caches on other nodes. This means
  1379. * scanning over all nodes to look for partial slabs which may be
  1380. * expensive if we do it every time we are trying to find a slab
  1381. * with available objects.
  1382. */
  1383. if (!s->remote_node_defrag_ratio ||
  1384. get_cycles() % 1024 > s->remote_node_defrag_ratio)
  1385. return NULL;
  1386. do {
  1387. cpuset_mems_cookie = get_mems_allowed();
  1388. zonelist = node_zonelist(slab_node(), flags);
  1389. for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
  1390. struct kmem_cache_node *n;
  1391. n = get_node(s, zone_to_nid(zone));
  1392. if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
  1393. n->nr_partial > s->min_partial) {
  1394. object = get_partial_node(s, n, c);
  1395. if (object) {
  1396. /*
  1397. * Return the object even if
  1398. * put_mems_allowed indicated that
  1399. * the cpuset mems_allowed was
  1400. * updated in parallel. It's a
  1401. * harmless race between the alloc
  1402. * and the cpuset update.
  1403. */
  1404. put_mems_allowed(cpuset_mems_cookie);
  1405. return object;
  1406. }
  1407. }
  1408. }
  1409. } while (!put_mems_allowed(cpuset_mems_cookie));
  1410. #endif
  1411. return NULL;
  1412. }
  1413. /*
  1414. * Get a partial page, lock it and return it.
  1415. */
  1416. static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
  1417. struct kmem_cache_cpu *c)
  1418. {
  1419. void *object;
  1420. int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
  1421. object = get_partial_node(s, get_node(s, searchnode), c);
  1422. if (object || node != NUMA_NO_NODE)
  1423. return object;
  1424. return get_any_partial(s, flags, c);
  1425. }
  1426. #ifdef CONFIG_PREEMPT
  1427. /*
  1428. * Calculate the next globally unique transaction for disambiguiation
  1429. * during cmpxchg. The transactions start with the cpu number and are then
  1430. * incremented by CONFIG_NR_CPUS.
  1431. */
  1432. #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
  1433. #else
  1434. /*
  1435. * No preemption supported therefore also no need to check for
  1436. * different cpus.
  1437. */
  1438. #define TID_STEP 1
  1439. #endif
  1440. static inline unsigned long next_tid(unsigned long tid)
  1441. {
  1442. return tid + TID_STEP;
  1443. }
  1444. static inline unsigned int tid_to_cpu(unsigned long tid)
  1445. {
  1446. return tid % TID_STEP;
  1447. }
  1448. static inline unsigned long tid_to_event(unsigned long tid)
  1449. {
  1450. return tid / TID_STEP;
  1451. }
  1452. static inline unsigned int init_tid(int cpu)
  1453. {
  1454. return cpu;
  1455. }
  1456. static inline void note_cmpxchg_failure(const char *n,
  1457. const struct kmem_cache *s, unsigned long tid)
  1458. {
  1459. #ifdef SLUB_DEBUG_CMPXCHG
  1460. unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
  1461. printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
  1462. #ifdef CONFIG_PREEMPT
  1463. if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
  1464. printk("due to cpu change %d -> %d\n",
  1465. tid_to_cpu(tid), tid_to_cpu(actual_tid));
  1466. else
  1467. #endif
  1468. if (tid_to_event(tid) != tid_to_event(actual_tid))
  1469. printk("due to cpu running other code. Event %ld->%ld\n",
  1470. tid_to_event(tid), tid_to_event(actual_tid));
  1471. else
  1472. printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
  1473. actual_tid, tid, next_tid(tid));
  1474. #endif
  1475. stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
  1476. }
  1477. void init_kmem_cache_cpus(struct kmem_cache *s)
  1478. {
  1479. int cpu;
  1480. for_each_possible_cpu(cpu)
  1481. per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
  1482. }
  1483. /*
  1484. * Remove the cpu slab
  1485. */
  1486. static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
  1487. {
  1488. enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
  1489. struct page *page = c->page;
  1490. struct kmem_cache_node *n = get_node(s, page_to_nid(page));
  1491. int lock = 0;
  1492. enum slab_modes l = M_NONE, m = M_NONE;
  1493. void *freelist;
  1494. void *nextfree;
  1495. int tail = DEACTIVATE_TO_HEAD;
  1496. struct page new;
  1497. struct page old;
  1498. if (page->freelist) {
  1499. stat(s, DEACTIVATE_REMOTE_FREES);
  1500. tail = DEACTIVATE_TO_TAIL;
  1501. }
  1502. c->tid = next_tid(c->tid);
  1503. c->page = NULL;
  1504. freelist = c->freelist;
  1505. c->freelist = NULL;
  1506. /*
  1507. * Stage one: Free all available per cpu objects back
  1508. * to the page freelist while it is still frozen. Leave the
  1509. * last one.
  1510. *
  1511. * There is no need to take the list->lock because the page
  1512. * is still frozen.
  1513. */
  1514. while (freelist && (nextfree = get_freepointer(s, freelist))) {
  1515. void *prior;
  1516. unsigned long counters;
  1517. do {
  1518. prior = page->freelist;
  1519. counters = page->counters;
  1520. set_freepointer(s, freelist, prior);
  1521. new.counters = counters;
  1522. new.inuse--;
  1523. VM_BUG_ON(!new.frozen);
  1524. } while (!__cmpxchg_double_slab(s, page,
  1525. prior, counters,
  1526. freelist, new.counters,
  1527. "drain percpu freelist"));
  1528. freelist = nextfree;
  1529. }
  1530. /*
  1531. * Stage two: Ensure that the page is unfrozen while the
  1532. * list presence reflects the actual number of objects
  1533. * during unfreeze.
  1534. *
  1535. * We setup the list membership and then perform a cmpxchg
  1536. * with the count. If there is a mismatch then the page
  1537. * is not unfrozen but the page is on the wrong list.
  1538. *
  1539. * Then we restart the process which may have to remove
  1540. * the page from the list that we just put it on again
  1541. * because the number of objects in the slab may have
  1542. * changed.
  1543. */
  1544. redo:
  1545. old.freelist = page->freelist;
  1546. old.counters = page->counters;
  1547. VM_BUG_ON(!old.frozen);
  1548. /* Determine target state of the slab */
  1549. new.counters = old.counters;
  1550. if (freelist) {
  1551. new.inuse--;
  1552. set_freepointer(s, freelist, old.freelist);
  1553. new.freelist = freelist;
  1554. } else
  1555. new.freelist = old.freelist;
  1556. new.frozen = 0;
  1557. if (!new.inuse && n->nr_partial > s->min_partial)
  1558. m = M_FREE;
  1559. else if (new.freelist) {
  1560. m = M_PARTIAL;
  1561. if (!lock) {
  1562. lock = 1;
  1563. /*
  1564. * Taking the spinlock removes the possiblity
  1565. * that acquire_slab() will see a slab page that
  1566. * is frozen
  1567. */
  1568. spin_lock(&n->list_lock);
  1569. }
  1570. } else {
  1571. m = M_FULL;
  1572. if (kmem_cache_debug(s) && !lock) {
  1573. lock = 1;
  1574. /*
  1575. * This also ensures that the scanning of full
  1576. * slabs from diagnostic functions will not see
  1577. * any frozen slabs.
  1578. */
  1579. spin_lock(&n->list_lock);
  1580. }
  1581. }
  1582. if (l != m) {
  1583. if (l == M_PARTIAL)
  1584. remove_partial(n, page);
  1585. else if (l == M_FULL)
  1586. remove_full(s, page);
  1587. if (m == M_PARTIAL) {
  1588. add_partial(n, page, tail);
  1589. stat(s, tail);
  1590. } else if (m == M_FULL) {
  1591. stat(s, DEACTIVATE_FULL);
  1592. add_full(s, n, page);
  1593. }
  1594. }
  1595. l = m;
  1596. if (!__cmpxchg_double_slab(s, page,
  1597. old.freelist, old.counters,
  1598. new.freelist, new.counters,
  1599. "unfreezing slab"))
  1600. goto redo;
  1601. if (lock)
  1602. spin_unlock(&n->list_lock);
  1603. if (m == M_FREE) {
  1604. stat(s, DEACTIVATE_EMPTY);
  1605. discard_slab(s, page);
  1606. stat(s, FREE_SLAB);
  1607. }
  1608. }
  1609. /* Unfreeze all the cpu partial slabs */
  1610. static void unfreeze_partials(struct kmem_cache *s)
  1611. {
  1612. struct kmem_cache_node *n = NULL, *n2 = NULL;
  1613. struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
  1614. struct page *page, *discard_page = NULL;
  1615. while ((page = c->partial)) {
  1616. struct page new;
  1617. struct page old;
  1618. c->partial = page->next;
  1619. n2 = get_node(s, page_to_nid(page));
  1620. if (n != n2) {
  1621. if (n)
  1622. spin_unlock(&n->list_lock);
  1623. n = n2;
  1624. spin_lock(&n->list_lock);
  1625. }
  1626. do {
  1627. old.freelist = page->freelist;
  1628. old.counters = page->counters;
  1629. VM_BUG_ON(!old.frozen);
  1630. new.counters = old.counters;
  1631. new.freelist = old.freelist;
  1632. new.frozen = 0;
  1633. } while (!cmpxchg_double_slab(s, page,
  1634. old.freelist, old.counters,
  1635. new.freelist, new.counters,
  1636. "unfreezing slab"));
  1637. if (unlikely(!new.inuse && n->nr_partial > s->min_partial)) {
  1638. page->next = discard_page;
  1639. discard_page = page;
  1640. } else {
  1641. add_partial(n, page, DEACTIVATE_TO_TAIL);
  1642. stat(s, FREE_ADD_PARTIAL);
  1643. }
  1644. }
  1645. if (n)
  1646. spin_unlock(&n->list_lock);
  1647. while (discard_page) {
  1648. page = discard_page;
  1649. discard_page = discard_page->next;
  1650. stat(s, DEACTIVATE_EMPTY);
  1651. discard_slab(s, page);
  1652. stat(s, FREE_SLAB);
  1653. }
  1654. }
  1655. /*
  1656. * Put a page that was just frozen (in __slab_free) into a partial page
  1657. * slot if available. This is done without interrupts disabled and without
  1658. * preemption disabled. The cmpxchg is racy and may put the partial page
  1659. * onto a random cpus partial slot.
  1660. *
  1661. * If we did not find a slot then simply move all the partials to the
  1662. * per node partial list.
  1663. */
  1664. int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
  1665. {
  1666. struct page *oldpage;
  1667. int pages;
  1668. int pobjects;
  1669. do {
  1670. pages = 0;
  1671. pobjects = 0;
  1672. oldpage = this_cpu_read(s->cpu_slab->partial);
  1673. if (oldpage) {
  1674. pobjects = oldpage->pobjects;
  1675. pages = oldpage->pages;
  1676. if (drain && pobjects > s->cpu_partial) {
  1677. unsigned long flags;
  1678. /*
  1679. * partial array is full. Move the existing
  1680. * set to the per node partial list.
  1681. */
  1682. local_irq_save(flags);
  1683. unfreeze_partials(s);
  1684. local_irq_restore(flags);
  1685. pobjects = 0;
  1686. pages = 0;
  1687. stat(s, CPU_PARTIAL_DRAIN);
  1688. }
  1689. }
  1690. pages++;
  1691. pobjects += page->objects - page->inuse;
  1692. page->pages = pages;
  1693. page->pobjects = pobjects;
  1694. page->next = oldpage;
  1695. } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
  1696. return pobjects;
  1697. }
  1698. static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
  1699. {
  1700. stat(s, CPUSLAB_FLUSH);
  1701. deactivate_slab(s, c);
  1702. }
  1703. /*
  1704. * Flush cpu slab.
  1705. *
  1706. * Called from IPI handler with interrupts disabled.
  1707. */
  1708. static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
  1709. {
  1710. struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
  1711. if (likely(c)) {
  1712. if (c->page)
  1713. flush_slab(s, c);
  1714. unfreeze_partials(s);
  1715. }
  1716. }
  1717. static void flush_cpu_slab(void *d)
  1718. {
  1719. struct kmem_cache *s = d;
  1720. __flush_cpu_slab(s, smp_processor_id());
  1721. }
  1722. static bool has_cpu_slab(int cpu, void *info)
  1723. {
  1724. struct kmem_cache *s = info;
  1725. struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
  1726. return c->page || c->partial;
  1727. }
  1728. static void flush_all(struct kmem_cache *s)
  1729. {
  1730. on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
  1731. }
  1732. /*
  1733. * Check if the objects in a per cpu structure fit numa
  1734. * locality expectations.
  1735. */
  1736. static inline int node_match(struct kmem_cache_cpu *c, int node)
  1737. {
  1738. #ifdef CONFIG_NUMA
  1739. if (node != NUMA_NO_NODE && c->node != node)
  1740. return 0;
  1741. #endif
  1742. return 1;
  1743. }
  1744. static int count_free(struct page *page)
  1745. {
  1746. return page->objects - page->inuse;
  1747. }
  1748. static unsigned long count_partial(struct kmem_cache_node *n,
  1749. int (*get_count)(struct page *))
  1750. {
  1751. unsigned long flags;
  1752. unsigned long x = 0;
  1753. struct page *page;
  1754. spin_lock_irqsave(&n->list_lock, flags);
  1755. list_for_each_entry(page, &n->partial, lru)
  1756. x += get_count(page);
  1757. spin_unlock_irqrestore(&n->list_lock, flags);
  1758. return x;
  1759. }
  1760. static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
  1761. {
  1762. #ifdef CONFIG_SLUB_DEBUG
  1763. return atomic_long_read(&n->total_objects);
  1764. #else
  1765. return 0;
  1766. #endif
  1767. }
  1768. static noinline void
  1769. slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
  1770. {
  1771. int node;
  1772. printk(KERN_WARNING
  1773. "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
  1774. nid, gfpflags);
  1775. printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
  1776. "default order: %d, min order: %d\n", s->name, s->objsize,
  1777. s->size, oo_order(s->oo), oo_order(s->min));
  1778. if (oo_order(s->min) > get_order(s->objsize))
  1779. printk(KERN_WARNING " %s debugging increased min order, use "
  1780. "slub_debug=O to disable.\n", s->name);
  1781. for_each_online_node(node) {
  1782. struct kmem_cache_node *n = get_node(s, node);
  1783. unsigned long nr_slabs;
  1784. unsigned long nr_objs;
  1785. unsigned long nr_free;
  1786. if (!n)
  1787. continue;
  1788. nr_free = count_partial(n, count_free);
  1789. nr_slabs = node_nr_slabs(n);
  1790. nr_objs = node_nr_objs(n);
  1791. printk(KERN_WARNING
  1792. " node %d: slabs: %ld, objs: %ld, free: %ld\n",
  1793. node, nr_slabs, nr_objs, nr_free);
  1794. }
  1795. }
  1796. static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
  1797. int node, struct kmem_cache_cpu **pc)
  1798. {
  1799. void *object;
  1800. struct kmem_cache_cpu *c;
  1801. struct page *page = new_slab(s, flags, node);
  1802. if (page) {
  1803. c = __this_cpu_ptr(s->cpu_slab);
  1804. if (c->page)
  1805. flush_slab(s, c);
  1806. /*
  1807. * No other reference to the page yet so we can
  1808. * muck around with it freely without cmpxchg
  1809. */
  1810. object = page->freelist;
  1811. page->freelist = NULL;
  1812. stat(s, ALLOC_SLAB);
  1813. c->node = page_to_nid(page);
  1814. c->page = page;
  1815. *pc = c;
  1816. } else
  1817. object = NULL;
  1818. return object;
  1819. }
  1820. /*
  1821. * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
  1822. * or deactivate the page.
  1823. *
  1824. * The page is still frozen if the return value is not NULL.
  1825. *
  1826. * If this function returns NULL then the page has been unfrozen.
  1827. */
  1828. static inline void *get_freelist(struct kmem_cache *s, struct page *page)
  1829. {
  1830. struct page new;
  1831. unsigned long counters;
  1832. void *freelist;
  1833. do {
  1834. freelist = page->freelist;
  1835. counters = page->counters;
  1836. new.counters = counters;
  1837. VM_BUG_ON(!new.frozen);
  1838. new.inuse = page->objects;
  1839. new.frozen = freelist != NULL;
  1840. } while (!cmpxchg_double_slab(s, page,
  1841. freelist, counters,
  1842. NULL, new.counters,
  1843. "get_freelist"));
  1844. return freelist;
  1845. }
  1846. /*
  1847. * Slow path. The lockless freelist is empty or we need to perform
  1848. * debugging duties.
  1849. *
  1850. * Processing is still very fast if new objects have been freed to the
  1851. * regular freelist. In that case we simply take over the regular freelist
  1852. * as the lockless freelist and zap the regular freelist.
  1853. *
  1854. * If that is not working then we fall back to the partial lists. We take the
  1855. * first element of the freelist as the object to allocate now and move the
  1856. * rest of the freelist to the lockless freelist.
  1857. *
  1858. * And if we were unable to get a new slab from the partial slab lists then
  1859. * we need to allocate a new slab. This is the slowest path since it involves
  1860. * a call to the page allocator and the setup of a new slab.
  1861. */
  1862. static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
  1863. unsigned long addr, struct kmem_cache_cpu *c)
  1864. {
  1865. void **object;
  1866. unsigned long flags;
  1867. local_irq_save(flags);
  1868. #ifdef CONFIG_PREEMPT
  1869. /*
  1870. * We may have been preempted and rescheduled on a different
  1871. * cpu before disabling interrupts. Need to reload cpu area
  1872. * pointer.
  1873. */
  1874. c = this_cpu_ptr(s->cpu_slab);
  1875. #endif
  1876. if (!c->page)
  1877. goto new_slab;
  1878. redo:
  1879. if (unlikely(!node_match(c, node))) {
  1880. stat(s, ALLOC_NODE_MISMATCH);
  1881. deactivate_slab(s, c);
  1882. goto new_slab;
  1883. }
  1884. /* must check again c->freelist in case of cpu migration or IRQ */
  1885. object = c->freelist;
  1886. if (object)
  1887. goto load_freelist;
  1888. stat(s, ALLOC_SLOWPATH);
  1889. object = get_freelist(s, c->page);
  1890. if (!object) {
  1891. c->page = NULL;
  1892. stat(s, DEACTIVATE_BYPASS);
  1893. goto new_slab;
  1894. }
  1895. stat(s, ALLOC_REFILL);
  1896. load_freelist:
  1897. c->freelist = get_freepointer(s, object);
  1898. c->tid = next_tid(c->tid);
  1899. local_irq_restore(flags);
  1900. return object;
  1901. new_slab:
  1902. if (c->partial) {
  1903. c->page = c->partial;
  1904. c->partial = c->page->next;
  1905. c->node = page_to_nid(c->page);
  1906. stat(s, CPU_PARTIAL_ALLOC);
  1907. c->freelist = NULL;
  1908. goto redo;
  1909. }
  1910. /* Then do expensive stuff like retrieving pages from the partial lists */
  1911. object = get_partial(s, gfpflags, node, c);
  1912. if (unlikely(!object)) {
  1913. object = new_slab_objects(s, gfpflags, node, &c);
  1914. if (unlikely(!object)) {
  1915. if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
  1916. slab_out_of_memory(s, gfpflags, node);
  1917. local_irq_restore(flags);
  1918. return NULL;
  1919. }
  1920. }
  1921. if (likely(!kmem_cache_debug(s)))
  1922. goto load_freelist;
  1923. /* Only entered in the debug case */
  1924. if (!alloc_debug_processing(s, c->page, object, addr))
  1925. goto new_slab; /* Slab failed checks. Next slab needed */
  1926. c->freelist = get_freepointer(s, object);
  1927. deactivate_slab(s, c);
  1928. c->node = NUMA_NO_NODE;
  1929. local_irq_restore(flags);
  1930. return object;
  1931. }
  1932. /*
  1933. * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
  1934. * have the fastpath folded into their functions. So no function call
  1935. * overhead for requests that can be satisfied on the fastpath.
  1936. *
  1937. * The fastpath works by first checking if the lockless freelist can be used.
  1938. * If not then __slab_alloc is called for slow processing.
  1939. *
  1940. * Otherwise we can simply pick the next object from the lockless free list.
  1941. */
  1942. static __always_inline void *slab_alloc(struct kmem_cache *s,
  1943. gfp_t gfpflags, int node, unsigned long addr)
  1944. {
  1945. void **object;
  1946. struct kmem_cache_cpu *c;
  1947. unsigned long tid;
  1948. if (slab_pre_alloc_hook(s, gfpflags))
  1949. return NULL;
  1950. redo:
  1951. /*
  1952. * Must read kmem_cache cpu data via this cpu ptr. Preemption is
  1953. * enabled. We may switch back and forth between cpus while
  1954. * reading from one cpu area. That does not matter as long
  1955. * as we end up on the original cpu again when doing the cmpxchg.
  1956. *
  1957. * Preemption is disabled for the retrieval of the tid because that
  1958. * must occur from the current processor. We cannot allow rescheduling
  1959. * on a different processor between the determination of the pointer
  1960. * and the retrieval of the tid.
  1961. */
  1962. preempt_disable();
  1963. c = __this_cpu_ptr(s->cpu_slab);
  1964. /*
  1965. * The transaction ids are globally unique per cpu and per operation on
  1966. * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
  1967. * occurs on the right processor and that there was no operation on the
  1968. * linked list in between.
  1969. */
  1970. tid = c->tid;
  1971. preempt_enable();
  1972. object = c->freelist;
  1973. if (unlikely(!object || !node_match(c, node)))
  1974. object = __slab_alloc(s, gfpflags, node, addr, c);
  1975. else {
  1976. void *next_object = get_freepointer_safe(s, object);
  1977. /*
  1978. * The cmpxchg will only match if there was no additional
  1979. * operation and if we are on the right processor.
  1980. *
  1981. * The cmpxchg does the following atomically (without lock semantics!)
  1982. * 1. Relocate first pointer to the current per cpu area.
  1983. * 2. Verify that tid and freelist have not been changed
  1984. * 3. If they were not changed replace tid and freelist
  1985. *
  1986. * Since this is without lock semantics the protection is only against
  1987. * code executing on this cpu *not* from access by other cpus.
  1988. */
  1989. if (unlikely(!this_cpu_cmpxchg_double(
  1990. s->cpu_slab->freelist, s->cpu_slab->tid,
  1991. object, tid,
  1992. next_object, next_tid(tid)))) {
  1993. note_cmpxchg_failure("slab_alloc", s, tid);
  1994. goto redo;
  1995. }
  1996. prefetch_freepointer(s, next_object);
  1997. stat(s, ALLOC_FASTPATH);
  1998. }
  1999. if (unlikely(gfpflags & __GFP_ZERO) && object)
  2000. memset(object, 0, s->objsize);
  2001. slab_post_alloc_hook(s, gfpflags, object);
  2002. return object;
  2003. }
  2004. void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
  2005. {
  2006. void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
  2007. trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
  2008. return ret;
  2009. }
  2010. EXPORT_SYMBOL(kmem_cache_alloc);
  2011. #ifdef CONFIG_TRACING
  2012. void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
  2013. {
  2014. void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
  2015. trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
  2016. return ret;
  2017. }
  2018. EXPORT_SYMBOL(kmem_cache_alloc_trace);
  2019. void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
  2020. {
  2021. void *ret = kmalloc_order(size, flags, order);
  2022. trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
  2023. return ret;
  2024. }
  2025. EXPORT_SYMBOL(kmalloc_order_trace);
  2026. #endif
  2027. #ifdef CONFIG_NUMA
  2028. void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
  2029. {
  2030. void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
  2031. trace_kmem_cache_alloc_node(_RET_IP_, ret,
  2032. s->objsize, s->size, gfpflags, node);
  2033. return ret;
  2034. }
  2035. EXPORT_SYMBOL(kmem_cache_alloc_node);
  2036. #ifdef CONFIG_TRACING
  2037. void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
  2038. gfp_t gfpflags,
  2039. int node, size_t size)
  2040. {
  2041. void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
  2042. trace_kmalloc_node(_RET_IP_, ret,
  2043. size, s->size, gfpflags, node);
  2044. return ret;
  2045. }
  2046. EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
  2047. #endif
  2048. #endif
  2049. /*
  2050. * Slow patch handling. This may still be called frequently since objects
  2051. * have a longer lifetime than the cpu slabs in most processing loads.
  2052. *
  2053. * So we still attempt to reduce cache line usage. Just take the slab
  2054. * lock and free the item. If there is no additional partial page
  2055. * handling required then we can return immediately.
  2056. */
  2057. static void __slab_free(struct kmem_cache *s, struct page *page,
  2058. void *x, unsigned long addr)
  2059. {
  2060. void *prior;
  2061. void **object = (void *)x;
  2062. int was_frozen;
  2063. int inuse;
  2064. struct page new;
  2065. unsigned long counters;
  2066. struct kmem_cache_node *n = NULL;
  2067. unsigned long uninitialized_var(flags);
  2068. stat(s, FREE_SLOWPATH);
  2069. if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
  2070. return;
  2071. do {
  2072. prior = page->freelist;
  2073. counters = page->counters;
  2074. set_freepointer(s, object, prior);
  2075. new.counters = counters;
  2076. was_frozen = new.frozen;
  2077. new.inuse--;
  2078. if ((!new.inuse || !prior) && !was_frozen && !n) {
  2079. if (!kmem_cache_debug(s) && !prior)
  2080. /*
  2081. * Slab was on no list before and will be partially empty
  2082. * We can defer the list move and instead freeze it.
  2083. */
  2084. new.frozen = 1;
  2085. else { /* Needs to be taken off a list */
  2086. n = get_node(s, page_to_nid(page));
  2087. /*
  2088. * Speculatively acquire the list_lock.
  2089. * If the cmpxchg does not succeed then we may
  2090. * drop the list_lock without any processing.
  2091. *
  2092. * Otherwise the list_lock will synchronize with
  2093. * other processors updating the list of slabs.
  2094. */
  2095. spin_lock_irqsave(&n->list_lock, flags);
  2096. }
  2097. }
  2098. inuse = new.inuse;
  2099. } while (!cmpxchg_double_slab(s, page,
  2100. prior, counters,
  2101. object, new.counters,
  2102. "__slab_free"));
  2103. if (likely(!n)) {
  2104. /*
  2105. * If we just froze the page then put it onto the
  2106. * per cpu partial list.
  2107. */
  2108. if (new.frozen && !was_frozen) {
  2109. put_cpu_partial(s, page, 1);
  2110. stat(s, CPU_PARTIAL_FREE);
  2111. }
  2112. /*
  2113. * The list lock was not taken therefore no list
  2114. * activity can be necessary.
  2115. */
  2116. if (was_frozen)
  2117. stat(s, FREE_FROZEN);
  2118. return;
  2119. }
  2120. /*
  2121. * was_frozen may have been set after we acquired the list_lock in
  2122. * an earlier loop. So we need to check it here again.
  2123. */
  2124. if (was_frozen)
  2125. stat(s, FREE_FROZEN);
  2126. else {
  2127. if (unlikely(!inuse && n->nr_partial > s->min_partial))
  2128. goto slab_empty;
  2129. /*
  2130. * Objects left in the slab. If it was not on the partial list before
  2131. * then add it.
  2132. */
  2133. if (unlikely(!prior)) {
  2134. remove_full(s, page);
  2135. add_partial(n, page, DEACTIVATE_TO_TAIL);
  2136. stat(s, FREE_ADD_PARTIAL);
  2137. }
  2138. }
  2139. spin_unlock_irqrestore(&n->list_lock, flags);
  2140. return;
  2141. slab_empty:
  2142. if (prior) {
  2143. /*
  2144. * Slab on the partial list.
  2145. */
  2146. remove_partial(n, page);
  2147. stat(s, FREE_REMOVE_PARTIAL);
  2148. } else
  2149. /* Slab must be on the full list */
  2150. remove_full(s, page);
  2151. spin_unlock_irqrestore(&n->list_lock, flags);
  2152. stat(s, FREE_SLAB);
  2153. discard_slab(s, page);
  2154. }
  2155. /*
  2156. * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
  2157. * can perform fastpath freeing without additional function calls.
  2158. *
  2159. * The fastpath is only possible if we are freeing to the current cpu slab
  2160. * of this processor. This typically the case if we have just allocated
  2161. * the item before.
  2162. *
  2163. * If fastpath is not possible then fall back to __slab_free where we deal
  2164. * with all sorts of special processing.
  2165. */
  2166. static __always_inline void slab_free(struct kmem_cache *s,
  2167. struct page *page, void *x, unsigned long addr)
  2168. {
  2169. void **object = (void *)x;
  2170. struct kmem_cache_cpu *c;
  2171. unsigned long tid;
  2172. slab_free_hook(s, x);
  2173. redo:
  2174. /*
  2175. * Determine the currently cpus per cpu slab.
  2176. * The cpu may change afterward. However that does not matter since
  2177. * data is retrieved via this pointer. If we are on the same cpu
  2178. * during the cmpxchg then the free will succedd.
  2179. */
  2180. preempt_disable();
  2181. c = __this_cpu_ptr(s->cpu_slab);
  2182. tid = c->tid;
  2183. preempt_enable();
  2184. if (likely(page == c->page)) {
  2185. set_freepointer(s, object, c->freelist);
  2186. if (unlikely(!this_cpu_cmpxchg_double(
  2187. s->cpu_slab->freelist, s->cpu_slab->tid,
  2188. c->freelist, tid,
  2189. object, next_tid(tid)))) {
  2190. note_cmpxchg_failure("slab_free", s, tid);
  2191. goto redo;
  2192. }
  2193. stat(s, FREE_FASTPATH);
  2194. } else
  2195. __slab_free(s, page, x, addr);
  2196. }
  2197. void kmem_cache_free(struct kmem_cache *s, void *x)
  2198. {
  2199. struct page *page;
  2200. page = virt_to_head_page(x);
  2201. slab_free(s, page, x, _RET_IP_);
  2202. trace_kmem_cache_free(_RET_IP_, x);
  2203. }
  2204. EXPORT_SYMBOL(kmem_cache_free);
  2205. /*
  2206. * Object placement in a slab is made very easy because we always start at
  2207. * offset 0. If we tune the size of the object to the alignment then we can
  2208. * get the required alignment by putting one properly sized object after
  2209. * another.
  2210. *
  2211. * Notice that the allocation order determines the sizes of the per cpu
  2212. * caches. Each processor has always one slab available for allocations.
  2213. * Increasing the allocation order reduces the number of times that slabs
  2214. * must be moved on and off the partial lists and is therefore a factor in
  2215. * locking overhead.
  2216. */
  2217. /*
  2218. * Mininum / Maximum order of slab pages. This influences locking overhead
  2219. * and slab fragmentation. A higher order reduces the number of partial slabs
  2220. * and increases the number of allocations possible without having to
  2221. * take the list_lock.
  2222. */
  2223. static int slub_min_order;
  2224. static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
  2225. static int slub_min_objects;
  2226. /*
  2227. * Merge control. If this is set then no merging of slab caches will occur.
  2228. * (Could be removed. This was introduced to pacify the merge skeptics.)
  2229. */
  2230. static int slub_nomerge;
  2231. /*
  2232. * Calculate the order of allocation given an slab object size.
  2233. *
  2234. * The order of allocation has significant impact on performance and other
  2235. * system components. Generally order 0 allocations should be preferred since
  2236. * order 0 does not cause fragmentation in the page allocator. Larger objects
  2237. * be problematic to put into order 0 slabs because there may be too much
  2238. * unused space left. We go to a higher order if more than 1/16th of the slab
  2239. * would be wasted.
  2240. *
  2241. * In order to reach satisfactory performance we must ensure that a minimum
  2242. * number of objects is in one slab. Otherwise we may generate too much
  2243. * activity on the partial lists which requires taking the list_lock. This is
  2244. * less a concern for large slabs though which are rarely used.
  2245. *
  2246. * slub_max_order specifies the order where we begin to stop considering the
  2247. * number of objects in a slab as critical. If we reach slub_max_order then
  2248. * we try to keep the page order as low as possible. So we accept more waste
  2249. * of space in favor of a small page order.
  2250. *
  2251. * Higher order allocations also allow the placement of more objects in a
  2252. * slab and thereby reduce object handling overhead. If the user has
  2253. * requested a higher mininum order then we start with that one instead of
  2254. * the smallest order which will fit the object.
  2255. */
  2256. static inline int slab_order(int size, int min_objects,
  2257. int max_order, int fract_leftover, int reserved)
  2258. {
  2259. int order;
  2260. int rem;
  2261. int min_order = slub_min_order;
  2262. if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
  2263. return get_order(size * MAX_OBJS_PER_PAGE) - 1;
  2264. for (order = max(min_order,
  2265. fls(min_objects * size - 1) - PAGE_SHIFT);
  2266. order <= max_order; order++) {
  2267. unsigned long slab_size = PAGE_SIZE << order;
  2268. if (slab_size < min_objects * size + reserved)
  2269. continue;
  2270. rem = (slab_size - reserved) % size;
  2271. if (rem <= slab_size / fract_leftover)
  2272. break;
  2273. }
  2274. return order;
  2275. }
  2276. static inline int calculate_order(int size, int reserved)
  2277. {
  2278. int order;
  2279. int min_objects;
  2280. int fraction;
  2281. int max_objects;
  2282. /*
  2283. * Attempt to find best configuration for a slab. This
  2284. * works by first attempting to generate a layout with
  2285. * the best configuration and backing off gradually.
  2286. *
  2287. * First we reduce the acceptable waste in a slab. Then
  2288. * we reduce the minimum objects required in a slab.
  2289. */
  2290. min_objects = slub_min_objects;
  2291. if (!min_objects)
  2292. min_objects = 4 * (fls(nr_cpu_ids) + 1);
  2293. max_objects = order_objects(slub_max_order, size, reserved);
  2294. min_objects = min(min_objects, max_objects);
  2295. while (min_objects > 1) {
  2296. fraction = 16;
  2297. while (fraction >= 4) {
  2298. order = slab_order(size, min_objects,
  2299. slub_max_order, fraction, reserved);
  2300. if (order <= slub_max_order)
  2301. return order;
  2302. fraction /= 2;
  2303. }
  2304. min_objects--;
  2305. }
  2306. /*
  2307. * We were unable to place multiple objects in a slab. Now
  2308. * lets see if we can place a single object there.
  2309. */
  2310. order = slab_order(size, 1, slub_max_order, 1, reserved);
  2311. if (order <= slub_max_order)
  2312. return order;
  2313. /*
  2314. * Doh this slab cannot be placed using slub_max_order.
  2315. */
  2316. order = slab_order(size, 1, MAX_ORDER, 1, reserved);
  2317. if (order < MAX_ORDER)
  2318. return order;
  2319. return -ENOSYS;
  2320. }
  2321. /*
  2322. * Figure out what the alignment of the objects will be.
  2323. */
  2324. static unsigned long calculate_alignment(unsigned long flags,
  2325. unsigned long align, unsigned long size)
  2326. {
  2327. /*
  2328. * If the user wants hardware cache aligned objects then follow that
  2329. * suggestion if the object is sufficiently large.
  2330. *
  2331. * The hardware cache alignment cannot override the specified
  2332. * alignment though. If that is greater then use it.
  2333. */
  2334. if (flags & SLAB_HWCACHE_ALIGN) {
  2335. unsigned long ralign = cache_line_size();
  2336. while (size <= ralign / 2)
  2337. ralign /= 2;
  2338. align = max(align, ralign);
  2339. }
  2340. if (align < ARCH_SLAB_MINALIGN)
  2341. align = ARCH_SLAB_MINALIGN;
  2342. return ALIGN(align, sizeof(void *));
  2343. }
  2344. static void
  2345. init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
  2346. {
  2347. n->nr_partial = 0;
  2348. spin_lock_init(&n->list_lock);
  2349. INIT_LIST_HEAD(&n->partial);
  2350. #ifdef CONFIG_SLUB_DEBUG
  2351. atomic_long_set(&n->nr_slabs, 0);
  2352. atomic_long_set(&n->total_objects, 0);
  2353. INIT_LIST_HEAD(&n->full);
  2354. #endif
  2355. }
  2356. static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
  2357. {
  2358. BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
  2359. SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
  2360. /*
  2361. * Must align to double word boundary for the double cmpxchg
  2362. * instructions to work; see __pcpu_double_call_return_bool().
  2363. */
  2364. s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
  2365. 2 * sizeof(void *));
  2366. if (!s->cpu_slab)
  2367. return 0;
  2368. init_kmem_cache_cpus(s);
  2369. return 1;
  2370. }
  2371. static struct kmem_cache *kmem_cache_node;
  2372. /*
  2373. * No kmalloc_node yet so do it by hand. We know that this is the first
  2374. * slab on the node for this slabcache. There are no concurrent accesses
  2375. * possible.
  2376. *
  2377. * Note that this function only works on the kmalloc_node_cache
  2378. * when allocating for the kmalloc_node_cache. This is used for bootstrapping
  2379. * memory on a fresh node that has no slab structures yet.
  2380. */
  2381. static void early_kmem_cache_node_alloc(int node)
  2382. {
  2383. struct page *page;
  2384. struct kmem_cache_node *n;
  2385. BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
  2386. page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
  2387. BUG_ON(!page);
  2388. if (page_to_nid(page) != node) {
  2389. printk(KERN_ERR "SLUB: Unable to allocate memory from "
  2390. "node %d\n", node);
  2391. printk(KERN_ERR "SLUB: Allocating a useless per node structure "
  2392. "in order to be able to continue\n");
  2393. }
  2394. n = page->freelist;
  2395. BUG_ON(!n);
  2396. page->freelist = get_freepointer(kmem_cache_node, n);
  2397. page->inuse = 1;
  2398. page->frozen = 0;
  2399. kmem_cache_node->node[node] = n;
  2400. #ifdef CONFIG_SLUB_DEBUG
  2401. init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
  2402. init_tracking(kmem_cache_node, n);
  2403. #endif
  2404. init_kmem_cache_node(n, kmem_cache_node);
  2405. inc_slabs_node(kmem_cache_node, node, page->objects);
  2406. add_partial(n, page, DEACTIVATE_TO_HEAD);
  2407. }
  2408. static void free_kmem_cache_nodes(struct kmem_cache *s)
  2409. {
  2410. int node;
  2411. for_each_node_state(node, N_NORMAL_MEMORY) {
  2412. struct kmem_cache_node *n = s->node[node];
  2413. if (n)
  2414. kmem_cache_free(kmem_cache_node, n);
  2415. s->node[node] = NULL;
  2416. }
  2417. }
  2418. static int init_kmem_cache_nodes(struct kmem_cache *s)
  2419. {
  2420. int node;
  2421. for_each_node_state(node, N_NORMAL_MEMORY) {
  2422. struct kmem_cache_node *n;
  2423. if (slab_state == DOWN) {
  2424. early_kmem_cache_node_alloc(node);
  2425. continue;
  2426. }
  2427. n = kmem_cache_alloc_node(kmem_cache_node,
  2428. GFP_KERNEL, node);
  2429. if (!n) {
  2430. free_kmem_cache_nodes(s);
  2431. return 0;
  2432. }
  2433. s->node[node] = n;
  2434. init_kmem_cache_node(n, s);
  2435. }
  2436. return 1;
  2437. }
  2438. static void set_min_partial(struct kmem_cache *s, unsigned long min)
  2439. {
  2440. if (min < MIN_PARTIAL)
  2441. min = MIN_PARTIAL;
  2442. else if (min > MAX_PARTIAL)
  2443. min = MAX_PARTIAL;
  2444. s->min_partial = min;
  2445. }
  2446. /*
  2447. * calculate_sizes() determines the order and the distribution of data within
  2448. * a slab object.
  2449. */
  2450. static int calculate_sizes(struct kmem_cache *s, int forced_order)
  2451. {
  2452. unsigned long flags = s->flags;
  2453. unsigned long size = s->objsize;
  2454. unsigned long align = s->align;
  2455. int order;
  2456. /*
  2457. * Round up object size to the next word boundary. We can only
  2458. * place the free pointer at word boundaries and this determines
  2459. * the possible location of the free pointer.
  2460. */
  2461. size = ALIGN(size, sizeof(void *));
  2462. #ifdef CONFIG_SLUB_DEBUG
  2463. /*
  2464. * Determine if we can poison the object itself. If the user of
  2465. * the slab may touch the object after free or before allocation
  2466. * then we should never poison the object itself.
  2467. */
  2468. if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
  2469. !s->ctor)
  2470. s->flags |= __OBJECT_POISON;
  2471. else
  2472. s->flags &= ~__OBJECT_POISON;
  2473. /*
  2474. * If we are Redzoning then check if there is some space between the
  2475. * end of the object and the free pointer. If not then add an
  2476. * additional word to have some bytes to store Redzone information.
  2477. */
  2478. if ((flags & SLAB_RED_ZONE) && size == s->objsize)
  2479. size += sizeof(void *);
  2480. #endif
  2481. /*
  2482. * With that we have determined the number of bytes in actual use
  2483. * by the object. This is the potential offset to the free pointer.
  2484. */
  2485. s->inuse = size;
  2486. if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
  2487. s->ctor)) {
  2488. /*
  2489. * Relocate free pointer after the object if it is not
  2490. * permitted to overwrite the first word of the object on
  2491. * kmem_cache_free.
  2492. *
  2493. * This is the case if we do RCU, have a constructor or
  2494. * destructor or are poisoning the objects.
  2495. */
  2496. s->offset = size;
  2497. size += sizeof(void *);
  2498. }
  2499. #ifdef CONFIG_SLUB_DEBUG
  2500. if (flags & SLAB_STORE_USER)
  2501. /*
  2502. * Need to store information about allocs and frees after
  2503. * the object.
  2504. */
  2505. size += 2 * sizeof(struct track);
  2506. if (flags & SLAB_RED_ZONE)
  2507. /*
  2508. * Add some empty padding so that we can catch
  2509. * overwrites from earlier objects rather than let
  2510. * tracking information or the free pointer be
  2511. * corrupted if a user writes before the start
  2512. * of the object.
  2513. */
  2514. size += sizeof(void *);
  2515. #endif
  2516. /*
  2517. * Determine the alignment based on various parameters that the
  2518. * user specified and the dynamic determination of cache line size
  2519. * on bootup.
  2520. */
  2521. align = calculate_alignment(flags, align, s->objsize);
  2522. s->align = align;
  2523. /*
  2524. * SLUB stores one object immediately after another beginning from
  2525. * offset 0. In order to align the objects we have to simply size
  2526. * each object to conform to the alignment.
  2527. */
  2528. size = ALIGN(size, align);
  2529. s->size = size;
  2530. if (forced_order >= 0)
  2531. order = forced_order;
  2532. else
  2533. order = calculate_order(size, s->reserved);
  2534. if (order < 0)
  2535. return 0;
  2536. s->allocflags = 0;
  2537. if (order)
  2538. s->allocflags |= __GFP_COMP;
  2539. if (s->flags & SLAB_CACHE_DMA)
  2540. s->allocflags |= SLUB_DMA;
  2541. if (s->flags & SLAB_RECLAIM_ACCOUNT)
  2542. s->allocflags |= __GFP_RECLAIMABLE;
  2543. /*
  2544. * Determine the number of objects per slab
  2545. */
  2546. s->oo = oo_make(order, size, s->reserved);
  2547. s->min = oo_make(get_order(size), size, s->reserved);
  2548. if (oo_objects(s->oo) > oo_objects(s->max))
  2549. s->max = s->oo;
  2550. return !!oo_objects(s->oo);
  2551. }
  2552. static int kmem_cache_open(struct kmem_cache *s,
  2553. const char *name, size_t size,
  2554. size_t align, unsigned long flags,
  2555. void (*ctor)(void *))
  2556. {
  2557. memset(s, 0, kmem_size);
  2558. s->name = name;
  2559. s->ctor = ctor;
  2560. s->objsize = size;
  2561. s->align = align;
  2562. s->flags = kmem_cache_flags(size, flags, name, ctor);
  2563. s->reserved = 0;
  2564. if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
  2565. s->reserved = sizeof(struct rcu_head);
  2566. if (!calculate_sizes(s, -1))
  2567. goto error;
  2568. if (disable_higher_order_debug) {
  2569. /*
  2570. * Disable debugging flags that store metadata if the min slab
  2571. * order increased.
  2572. */
  2573. if (get_order(s->size) > get_order(s->objsize)) {
  2574. s->flags &= ~DEBUG_METADATA_FLAGS;
  2575. s->offset = 0;
  2576. if (!calculate_sizes(s, -1))
  2577. goto error;
  2578. }
  2579. }
  2580. #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
  2581. defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
  2582. if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
  2583. /* Enable fast mode */
  2584. s->flags |= __CMPXCHG_DOUBLE;
  2585. #endif
  2586. /*
  2587. * The larger the object size is, the more pages we want on the partial
  2588. * list to avoid pounding the page allocator excessively.
  2589. */
  2590. set_min_partial(s, ilog2(s->size) / 2);
  2591. /*
  2592. * cpu_partial determined the maximum number of objects kept in the
  2593. * per cpu partial lists of a processor.
  2594. *
  2595. * Per cpu partial lists mainly contain slabs that just have one
  2596. * object freed. If they are used for allocation then they can be
  2597. * filled up again with minimal effort. The slab will never hit the
  2598. * per node partial lists and therefore no locking will be required.
  2599. *
  2600. * This setting also determines
  2601. *
  2602. * A) The number of objects from per cpu partial slabs dumped to the
  2603. * per node list when we reach the limit.
  2604. * B) The number of objects in cpu partial slabs to extract from the
  2605. * per node list when we run out of per cpu objects. We only fetch 50%
  2606. * to keep some capacity around for frees.
  2607. */
  2608. if (kmem_cache_debug(s))
  2609. s->cpu_partial = 0;
  2610. else if (s->size >= PAGE_SIZE)
  2611. s->cpu_partial = 2;
  2612. else if (s->size >= 1024)
  2613. s->cpu_partial = 6;
  2614. else if (s->size >= 256)
  2615. s->cpu_partial = 13;
  2616. else
  2617. s->cpu_partial = 30;
  2618. s->refcount = 1;
  2619. #ifdef CONFIG_NUMA
  2620. s->remote_node_defrag_ratio = 1000;
  2621. #endif
  2622. if (!init_kmem_cache_nodes(s))
  2623. goto error;
  2624. if (alloc_kmem_cache_cpus(s))
  2625. return 1;
  2626. free_kmem_cache_nodes(s);
  2627. error:
  2628. if (flags & SLAB_PANIC)
  2629. panic("Cannot create slab %s size=%lu realsize=%u "
  2630. "order=%u offset=%u flags=%lx\n",
  2631. s->name, (unsigned long)size, s->size, oo_order(s->oo),
  2632. s->offset, flags);
  2633. return 0;
  2634. }
  2635. /*
  2636. * Determine the size of a slab object
  2637. */
  2638. unsigned int kmem_cache_size(struct kmem_cache *s)
  2639. {
  2640. return s->objsize;
  2641. }
  2642. EXPORT_SYMBOL(kmem_cache_size);
  2643. static void list_slab_objects(struct kmem_cache *s, struct page *page,
  2644. const char *text)
  2645. {
  2646. #ifdef CONFIG_SLUB_DEBUG
  2647. void *addr = page_address(page);
  2648. void *p;
  2649. unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
  2650. sizeof(long), GFP_ATOMIC);
  2651. if (!map)
  2652. return;
  2653. slab_err(s, page, "%s", text);
  2654. slab_lock(page);
  2655. get_map(s, page, map);
  2656. for_each_object(p, s, addr, page->objects) {
  2657. if (!test_bit(slab_index(p, s, addr), map)) {
  2658. printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
  2659. p, p - addr);
  2660. print_tracking(s, p);
  2661. }
  2662. }
  2663. slab_unlock(page);
  2664. kfree(map);
  2665. #endif
  2666. }
  2667. /*
  2668. * Attempt to free all partial slabs on a node.
  2669. * This is called from kmem_cache_close(). We must be the last thread
  2670. * using the cache and therefore we do not need to lock anymore.
  2671. */
  2672. static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
  2673. {
  2674. struct page *page, *h;
  2675. list_for_each_entry_safe(page, h, &n->partial, lru) {
  2676. if (!page->inuse) {
  2677. remove_partial(n, page);
  2678. discard_slab(s, page);
  2679. } else {
  2680. list_slab_objects(s, page,
  2681. "Objects remaining on kmem_cache_close()");
  2682. }
  2683. }
  2684. }
  2685. /*
  2686. * Release all resources used by a slab cache.
  2687. */
  2688. static inline int kmem_cache_close(struct kmem_cache *s)
  2689. {
  2690. int node;
  2691. flush_all(s);
  2692. free_percpu(s->cpu_slab);
  2693. /* Attempt to free all objects */
  2694. for_each_node_state(node, N_NORMAL_MEMORY) {
  2695. struct kmem_cache_node *n = get_node(s, node);
  2696. free_partial(s, n);
  2697. if (n->nr_partial || slabs_node(s, node))
  2698. return 1;
  2699. }
  2700. free_kmem_cache_nodes(s);
  2701. return 0;
  2702. }
  2703. /*
  2704. * Close a cache and release the kmem_cache structure
  2705. * (must be used for caches created using kmem_cache_create)
  2706. */
  2707. void kmem_cache_destroy(struct kmem_cache *s)
  2708. {
  2709. down_write(&slub_lock);
  2710. s->refcount--;
  2711. if (!s->refcount) {
  2712. list_del(&s->list);
  2713. up_write(&slub_lock);
  2714. if (kmem_cache_close(s)) {
  2715. printk(KERN_ERR "SLUB %s: %s called for cache that "
  2716. "still has objects.\n", s->name, __func__);
  2717. dump_stack();
  2718. }
  2719. if (s->flags & SLAB_DESTROY_BY_RCU)
  2720. rcu_barrier();
  2721. sysfs_slab_remove(s);
  2722. } else
  2723. up_write(&slub_lock);
  2724. }
  2725. EXPORT_SYMBOL(kmem_cache_destroy);
  2726. /********************************************************************
  2727. * Kmalloc subsystem
  2728. *******************************************************************/
  2729. struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
  2730. EXPORT_SYMBOL(kmalloc_caches);
  2731. static struct kmem_cache *kmem_cache;
  2732. #ifdef CONFIG_ZONE_DMA
  2733. static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
  2734. #endif
  2735. static int __init setup_slub_min_order(char *str)
  2736. {
  2737. get_option(&str, &slub_min_order);
  2738. return 1;
  2739. }
  2740. __setup("slub_min_order=", setup_slub_min_order);
  2741. static int __init setup_slub_max_order(char *str)
  2742. {
  2743. get_option(&str, &slub_max_order);
  2744. slub_max_order = min(slub_max_order, MAX_ORDER - 1);
  2745. return 1;
  2746. }
  2747. __setup("slub_max_order=", setup_slub_max_order);
  2748. static int __init setup_slub_min_objects(char *str)
  2749. {
  2750. get_option(&str, &slub_min_objects);
  2751. return 1;
  2752. }
  2753. __setup("slub_min_objects=", setup_slub_min_objects);
  2754. static int __init setup_slub_nomerge(char *str)
  2755. {
  2756. slub_nomerge = 1;
  2757. return 1;
  2758. }
  2759. __setup("slub_nomerge", setup_slub_nomerge);
  2760. static struct kmem_cache *__init create_kmalloc_cache(const char *name,
  2761. int size, unsigned int flags)
  2762. {
  2763. struct kmem_cache *s;
  2764. s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
  2765. /*
  2766. * This function is called with IRQs disabled during early-boot on
  2767. * single CPU so there's no need to take slub_lock here.
  2768. */
  2769. if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
  2770. flags, NULL))
  2771. goto panic;
  2772. list_add(&s->list, &slab_caches);
  2773. return s;
  2774. panic:
  2775. panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
  2776. return NULL;
  2777. }
  2778. /*
  2779. * Conversion table for small slabs sizes / 8 to the index in the
  2780. * kmalloc array. This is necessary for slabs < 192 since we have non power
  2781. * of two cache sizes there. The size of larger slabs can be determined using
  2782. * fls.
  2783. */
  2784. static s8 size_index[24] = {
  2785. 3, /* 8 */
  2786. 4, /* 16 */
  2787. 5, /* 24 */
  2788. 5, /* 32 */
  2789. 6, /* 40 */
  2790. 6, /* 48 */
  2791. 6, /* 56 */
  2792. 6, /* 64 */
  2793. 1, /* 72 */
  2794. 1, /* 80 */
  2795. 1, /* 88 */
  2796. 1, /* 96 */
  2797. 7, /* 104 */
  2798. 7, /* 112 */
  2799. 7, /* 120 */
  2800. 7, /* 128 */
  2801. 2, /* 136 */
  2802. 2, /* 144 */
  2803. 2, /* 152 */
  2804. 2, /* 160 */
  2805. 2, /* 168 */
  2806. 2, /* 176 */
  2807. 2, /* 184 */
  2808. 2 /* 192 */
  2809. };
  2810. static inline int size_index_elem(size_t bytes)
  2811. {
  2812. return (bytes - 1) / 8;
  2813. }
  2814. static struct kmem_cache *get_slab(size_t size, gfp_t flags)
  2815. {
  2816. int index;
  2817. if (size <= 192) {
  2818. if (!size)
  2819. return ZERO_SIZE_PTR;
  2820. index = size_index[size_index_elem(size)];
  2821. } else
  2822. index = fls(size - 1);
  2823. #ifdef CONFIG_ZONE_DMA
  2824. if (unlikely((flags & SLUB_DMA)))
  2825. return kmalloc_dma_caches[index];
  2826. #endif
  2827. return kmalloc_caches[index];
  2828. }
  2829. void *__kmalloc(size_t size, gfp_t flags)
  2830. {
  2831. struct kmem_cache *s;
  2832. void *ret;
  2833. if (unlikely(size > SLUB_MAX_SIZE))
  2834. return kmalloc_large(size, flags);
  2835. s = get_slab(size, flags);
  2836. if (unlikely(ZERO_OR_NULL_PTR(s)))
  2837. return s;
  2838. ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
  2839. trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
  2840. return ret;
  2841. }
  2842. EXPORT_SYMBOL(__kmalloc);
  2843. #ifdef CONFIG_NUMA
  2844. static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
  2845. {
  2846. struct page *page;
  2847. void *ptr = NULL;
  2848. flags |= __GFP_COMP | __GFP_NOTRACK;
  2849. page = alloc_pages_node(node, flags, get_order(size));
  2850. if (page)
  2851. ptr = page_address(page);
  2852. kmemleak_alloc(ptr, size, 1, flags);
  2853. return ptr;
  2854. }
  2855. void *__kmalloc_node(size_t size, gfp_t flags, int node)
  2856. {
  2857. struct kmem_cache *s;
  2858. void *ret;
  2859. if (unlikely(size > SLUB_MAX_SIZE)) {
  2860. ret = kmalloc_large_node(size, flags, node);
  2861. trace_kmalloc_node(_RET_IP_, ret,
  2862. size, PAGE_SIZE << get_order(size),
  2863. flags, node);
  2864. return ret;
  2865. }
  2866. s = get_slab(size, flags);
  2867. if (unlikely(ZERO_OR_NULL_PTR(s)))
  2868. return s;
  2869. ret = slab_alloc(s, flags, node, _RET_IP_);
  2870. trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
  2871. return ret;
  2872. }
  2873. EXPORT_SYMBOL(__kmalloc_node);
  2874. #endif
  2875. size_t ksize(const void *object)
  2876. {
  2877. struct page *page;
  2878. if (unlikely(object == ZERO_SIZE_PTR))
  2879. return 0;
  2880. page = virt_to_head_page(object);
  2881. if (unlikely(!PageSlab(page))) {
  2882. WARN_ON(!PageCompound(page));
  2883. return PAGE_SIZE << compound_order(page);
  2884. }
  2885. return slab_ksize(page->slab);
  2886. }
  2887. EXPORT_SYMBOL(ksize);
  2888. #ifdef CONFIG_SLUB_DEBUG
  2889. bool verify_mem_not_deleted(const void *x)
  2890. {
  2891. struct page *page;
  2892. void *object = (void *)x;
  2893. unsigned long flags;
  2894. bool rv;
  2895. if (unlikely(ZERO_OR_NULL_PTR(x)))
  2896. return false;
  2897. local_irq_save(flags);
  2898. page = virt_to_head_page(x);
  2899. if (unlikely(!PageSlab(page))) {
  2900. /* maybe it was from stack? */
  2901. rv = true;
  2902. goto out_unlock;
  2903. }
  2904. slab_lock(page);
  2905. if (on_freelist(page->slab, page, object)) {
  2906. object_err(page->slab, page, object, "Object is on free-list");
  2907. rv = false;
  2908. } else {
  2909. rv = true;
  2910. }
  2911. slab_unlock(page);
  2912. out_unlock:
  2913. local_irq_restore(flags);
  2914. return rv;
  2915. }
  2916. EXPORT_SYMBOL(verify_mem_not_deleted);
  2917. #endif
  2918. #ifdef CONFIG_SEC_DEBUG_DOUBLE_FREE
  2919. void kfree(const void *y)
  2920. #else
  2921. void kfree(const void *x)
  2922. #endif
  2923. {
  2924. struct page *page;
  2925. #ifdef CONFIG_SEC_DEBUG_DOUBLE_FREE
  2926. void *x = (void *)y;
  2927. #endif
  2928. void *object = (void *)x;
  2929. #ifdef CONFIG_SEC_DEBUG_DOUBLE_FREE
  2930. object = x = kfree_hook(x, __builtin_return_address(0));
  2931. if (!x)
  2932. return;
  2933. #endif
  2934. trace_kfree(_RET_IP_, x);
  2935. if (unlikely(ZERO_OR_NULL_PTR(x)))
  2936. return;
  2937. page = virt_to_head_page(x);
  2938. if (unlikely(!PageSlab(page))) {
  2939. BUG_ON(!PageCompound(page));
  2940. kmemleak_free(x);
  2941. put_page(page);
  2942. return;
  2943. }
  2944. slab_free(page->slab, page, object, _RET_IP_);
  2945. }
  2946. EXPORT_SYMBOL(kfree);
  2947. /*
  2948. * kmem_cache_shrink removes empty slabs from the partial lists and sorts
  2949. * the remaining slabs by the number of items in use. The slabs with the
  2950. * most items in use come first. New allocations will then fill those up
  2951. * and thus they can be removed from the partial lists.
  2952. *
  2953. * The slabs with the least items are placed last. This results in them
  2954. * being allocated from last increasing the chance that the last objects
  2955. * are freed in them.
  2956. */
  2957. int kmem_cache_shrink(struct kmem_cache *s)
  2958. {
  2959. int node;
  2960. int i;
  2961. struct kmem_cache_node *n;
  2962. struct page *page;
  2963. struct page *t;
  2964. int objects = oo_objects(s->max);
  2965. struct list_head *slabs_by_inuse =
  2966. kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
  2967. unsigned long flags;
  2968. if (!slabs_by_inuse)
  2969. return -ENOMEM;
  2970. flush_all(s);
  2971. for_each_node_state(node, N_NORMAL_MEMORY) {
  2972. n = get_node(s, node);
  2973. if (!n->nr_partial)
  2974. continue;
  2975. for (i = 0; i < objects; i++)
  2976. INIT_LIST_HEAD(slabs_by_inuse + i);
  2977. spin_lock_irqsave(&n->list_lock, flags);
  2978. /*
  2979. * Build lists indexed by the items in use in each slab.
  2980. *
  2981. * Note that concurrent frees may occur while we hold the
  2982. * list_lock. page->inuse here is the upper limit.
  2983. */
  2984. list_for_each_entry_safe(page, t, &n->partial, lru) {
  2985. list_move(&page->lru, slabs_by_inuse + page->inuse);
  2986. if (!page->inuse)
  2987. n->nr_partial--;
  2988. }
  2989. /*
  2990. * Rebuild the partial list with the slabs filled up most
  2991. * first and the least used slabs at the end.
  2992. */
  2993. for (i = objects - 1; i > 0; i--)
  2994. list_splice(slabs_by_inuse + i, n->partial.prev);
  2995. spin_unlock_irqrestore(&n->list_lock, flags);
  2996. /* Release empty slabs */
  2997. list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
  2998. discard_slab(s, page);
  2999. }
  3000. kfree(slabs_by_inuse);
  3001. return 0;
  3002. }
  3003. EXPORT_SYMBOL(kmem_cache_shrink);
  3004. #if defined(CONFIG_MEMORY_HOTPLUG)
  3005. static int slab_mem_going_offline_callback(void *arg)
  3006. {
  3007. struct kmem_cache *s;
  3008. down_read(&slub_lock);
  3009. list_for_each_entry(s, &slab_caches, list)
  3010. kmem_cache_shrink(s);
  3011. up_read(&slub_lock);
  3012. return 0;
  3013. }
  3014. static void slab_mem_offline_callback(void *arg)
  3015. {
  3016. struct kmem_cache_node *n;
  3017. struct kmem_cache *s;
  3018. struct memory_notify *marg = arg;
  3019. int offline_node;
  3020. offline_node = marg->status_change_nid;
  3021. /*
  3022. * If the node still has available memory. we need kmem_cache_node
  3023. * for it yet.
  3024. */
  3025. if (offline_node < 0)
  3026. return;
  3027. down_read(&slub_lock);
  3028. list_for_each_entry(s, &slab_caches, list) {
  3029. n = get_node(s, offline_node);
  3030. if (n) {
  3031. /*
  3032. * if n->nr_slabs > 0, slabs still exist on the node
  3033. * that is going down. We were unable to free them,
  3034. * and offline_pages() function shouldn't call this
  3035. * callback. So, we must fail.
  3036. */
  3037. BUG_ON(slabs_node(s, offline_node));
  3038. s->node[offline_node] = NULL;
  3039. kmem_cache_free(kmem_cache_node, n);
  3040. }
  3041. }
  3042. up_read(&slub_lock);
  3043. }
  3044. static int slab_mem_going_online_callback(void *arg)
  3045. {
  3046. struct kmem_cache_node *n;
  3047. struct kmem_cache *s;
  3048. struct memory_notify *marg = arg;
  3049. int nid = marg->status_change_nid;
  3050. int ret = 0;
  3051. /*
  3052. * If the node's memory is already available, then kmem_cache_node is
  3053. * already created. Nothing to do.
  3054. */
  3055. if (nid < 0)
  3056. return 0;
  3057. /*
  3058. * We are bringing a node online. No memory is available yet. We must
  3059. * allocate a kmem_cache_node structure in order to bring the node
  3060. * online.
  3061. */
  3062. down_read(&slub_lock);
  3063. list_for_each_entry(s, &slab_caches, list) {
  3064. /*
  3065. * XXX: kmem_cache_alloc_node will fallback to other nodes
  3066. * since memory is not yet available from the node that
  3067. * is brought up.
  3068. */
  3069. n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
  3070. if (!n) {
  3071. ret = -ENOMEM;
  3072. goto out;
  3073. }
  3074. init_kmem_cache_node(n, s);
  3075. s->node[nid] = n;
  3076. }
  3077. out:
  3078. up_read(&slub_lock);
  3079. return ret;
  3080. }
  3081. static int slab_memory_callback(struct notifier_block *self,
  3082. unsigned long action, void *arg)
  3083. {
  3084. int ret = 0;
  3085. switch (action) {
  3086. case MEM_GOING_ONLINE:
  3087. ret = slab_mem_going_online_callback(arg);
  3088. break;
  3089. case MEM_GOING_OFFLINE:
  3090. ret = slab_mem_going_offline_callback(arg);
  3091. break;
  3092. case MEM_OFFLINE:
  3093. case MEM_CANCEL_ONLINE:
  3094. slab_mem_offline_callback(arg);
  3095. break;
  3096. case MEM_ONLINE:
  3097. case MEM_CANCEL_OFFLINE:
  3098. break;
  3099. }
  3100. if (ret)
  3101. ret = notifier_from_errno(ret);
  3102. else
  3103. ret = NOTIFY_OK;
  3104. return ret;
  3105. }
  3106. #endif /* CONFIG_MEMORY_HOTPLUG */
  3107. /********************************************************************
  3108. * Basic setup of slabs
  3109. *******************************************************************/
  3110. /*
  3111. * Used for early kmem_cache structures that were allocated using
  3112. * the page allocator
  3113. */
  3114. static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s)
  3115. {
  3116. int node;
  3117. list_add(&s->list, &slab_caches);
  3118. s->refcount = -1;
  3119. for_each_node_state(node, N_NORMAL_MEMORY) {
  3120. struct kmem_cache_node *n = get_node(s, node);
  3121. struct page *p;
  3122. if (n) {
  3123. list_for_each_entry(p, &n->partial, lru)
  3124. p->slab = s;
  3125. #ifdef CONFIG_SLUB_DEBUG
  3126. list_for_each_entry(p, &n->full, lru)
  3127. p->slab = s;
  3128. #endif
  3129. }
  3130. }
  3131. }
  3132. void __init kmem_cache_init(void)
  3133. {
  3134. int i;
  3135. int caches = 0;
  3136. struct kmem_cache *temp_kmem_cache;
  3137. int order;
  3138. struct kmem_cache *temp_kmem_cache_node;
  3139. unsigned long kmalloc_size;
  3140. if (debug_guardpage_minorder())
  3141. slub_max_order = 0;
  3142. kmem_size = offsetof(struct kmem_cache, node) +
  3143. nr_node_ids * sizeof(struct kmem_cache_node *);
  3144. /* Allocate two kmem_caches from the page allocator */
  3145. kmalloc_size = ALIGN(kmem_size, cache_line_size());
  3146. order = get_order(2 * kmalloc_size);
  3147. kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
  3148. /*
  3149. * Must first have the slab cache available for the allocations of the
  3150. * struct kmem_cache_node's. There is special bootstrap code in
  3151. * kmem_cache_open for slab_state == DOWN.
  3152. */
  3153. kmem_cache_node = (void *)kmem_cache + kmalloc_size;
  3154. kmem_cache_open(kmem_cache_node, "kmem_cache_node",
  3155. sizeof(struct kmem_cache_node),
  3156. 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
  3157. hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
  3158. /* Able to allocate the per node structures */
  3159. slab_state = PARTIAL;
  3160. temp_kmem_cache = kmem_cache;
  3161. kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
  3162. 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
  3163. kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
  3164. memcpy(kmem_cache, temp_kmem_cache, kmem_size);
  3165. /*
  3166. * Allocate kmem_cache_node properly from the kmem_cache slab.
  3167. * kmem_cache_node is separately allocated so no need to
  3168. * update any list pointers.
  3169. */
  3170. temp_kmem_cache_node = kmem_cache_node;
  3171. kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
  3172. memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
  3173. kmem_cache_bootstrap_fixup(kmem_cache_node);
  3174. caches++;
  3175. kmem_cache_bootstrap_fixup(kmem_cache);
  3176. caches++;
  3177. /* Free temporary boot structure */
  3178. free_pages((unsigned long)temp_kmem_cache, order);
  3179. /* Now we can use the kmem_cache to allocate kmalloc slabs */
  3180. /*
  3181. * Patch up the size_index table if we have strange large alignment
  3182. * requirements for the kmalloc array. This is only the case for
  3183. * MIPS it seems. The standard arches will not generate any code here.
  3184. *
  3185. * Largest permitted alignment is 256 bytes due to the way we
  3186. * handle the index determination for the smaller caches.
  3187. *
  3188. * Make sure that nothing crazy happens if someone starts tinkering
  3189. * around with ARCH_KMALLOC_MINALIGN
  3190. */
  3191. BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
  3192. (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
  3193. for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
  3194. int elem = size_index_elem(i);
  3195. if (elem >= ARRAY_SIZE(size_index))
  3196. break;
  3197. size_index[elem] = KMALLOC_SHIFT_LOW;
  3198. }
  3199. if (KMALLOC_MIN_SIZE == 64) {
  3200. /*
  3201. * The 96 byte size cache is not used if the alignment
  3202. * is 64 byte.
  3203. */
  3204. for (i = 64 + 8; i <= 96; i += 8)
  3205. size_index[size_index_elem(i)] = 7;
  3206. } else if (KMALLOC_MIN_SIZE == 128) {
  3207. /*
  3208. * The 192 byte sized cache is not used if the alignment
  3209. * is 128 byte. Redirect kmalloc to use the 256 byte cache
  3210. * instead.
  3211. */
  3212. for (i = 128 + 8; i <= 192; i += 8)
  3213. size_index[size_index_elem(i)] = 8;
  3214. }
  3215. /* Caches that are not of the two-to-the-power-of size */
  3216. if (KMALLOC_MIN_SIZE <= 32) {
  3217. kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
  3218. caches++;
  3219. }
  3220. if (KMALLOC_MIN_SIZE <= 64) {
  3221. kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
  3222. caches++;
  3223. }
  3224. for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
  3225. kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
  3226. caches++;
  3227. }
  3228. slab_state = UP;
  3229. /* Provide the correct kmalloc names now that the caches are up */
  3230. if (KMALLOC_MIN_SIZE <= 32) {
  3231. kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
  3232. BUG_ON(!kmalloc_caches[1]->name);
  3233. }
  3234. if (KMALLOC_MIN_SIZE <= 64) {
  3235. kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
  3236. BUG_ON(!kmalloc_caches[2]->name);
  3237. }
  3238. for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
  3239. char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
  3240. BUG_ON(!s);
  3241. kmalloc_caches[i]->name = s;
  3242. }
  3243. #ifdef CONFIG_SMP
  3244. register_cpu_notifier(&slab_notifier);
  3245. #endif
  3246. #ifdef CONFIG_ZONE_DMA
  3247. for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
  3248. struct kmem_cache *s = kmalloc_caches[i];
  3249. if (s && s->size) {
  3250. char *name = kasprintf(GFP_NOWAIT,
  3251. "dma-kmalloc-%d", s->objsize);
  3252. BUG_ON(!name);
  3253. kmalloc_dma_caches[i] = create_kmalloc_cache(name,
  3254. s->objsize, SLAB_CACHE_DMA);
  3255. }
  3256. }
  3257. #endif
  3258. printk(KERN_INFO
  3259. "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
  3260. " CPUs=%d, Nodes=%d\n",
  3261. caches, cache_line_size(),
  3262. slub_min_order, slub_max_order, slub_min_objects,
  3263. nr_cpu_ids, nr_node_ids);
  3264. }
  3265. void __init kmem_cache_init_late(void)
  3266. {
  3267. }
  3268. /*
  3269. * Find a mergeable slab cache
  3270. */
  3271. static int slab_unmergeable(struct kmem_cache *s)
  3272. {
  3273. if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
  3274. return 1;
  3275. if (s->ctor)
  3276. return 1;
  3277. /*
  3278. * We may have set a slab to be unmergeable during bootstrap.
  3279. */
  3280. if (s->refcount < 0)
  3281. return 1;
  3282. return 0;
  3283. }
  3284. static struct kmem_cache *find_mergeable(size_t size,
  3285. size_t align, unsigned long flags, const char *name,
  3286. void (*ctor)(void *))
  3287. {
  3288. struct kmem_cache *s;
  3289. if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
  3290. return NULL;
  3291. if (ctor)
  3292. return NULL;
  3293. size = ALIGN(size, sizeof(void *));
  3294. align = calculate_alignment(flags, align, size);
  3295. size = ALIGN(size, align);
  3296. flags = kmem_cache_flags(size, flags, name, NULL);
  3297. list_for_each_entry(s, &slab_caches, list) {
  3298. if (slab_unmergeable(s))
  3299. continue;
  3300. if (size > s->size)
  3301. continue;
  3302. if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
  3303. continue;
  3304. /*
  3305. * Check if alignment is compatible.
  3306. * Courtesy of Adrian Drzewiecki
  3307. */
  3308. if ((s->size & ~(align - 1)) != s->size)
  3309. continue;
  3310. if (s->size - size >= sizeof(void *))
  3311. continue;
  3312. return s;
  3313. }
  3314. return NULL;
  3315. }
  3316. struct kmem_cache *kmem_cache_create(const char *name, size_t size,
  3317. size_t align, unsigned long flags, void (*ctor)(void *))
  3318. {
  3319. struct kmem_cache *s;
  3320. char *n;
  3321. if (WARN_ON(!name))
  3322. return NULL;
  3323. down_write(&slub_lock);
  3324. s = find_mergeable(size, align, flags, name, ctor);
  3325. if (s) {
  3326. s->refcount++;
  3327. /*
  3328. * Adjust the object sizes so that we clear
  3329. * the complete object on kzalloc.
  3330. */
  3331. s->objsize = max(s->objsize, (int)size);
  3332. s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
  3333. if (sysfs_slab_alias(s, name)) {
  3334. s->refcount--;
  3335. goto err;
  3336. }
  3337. up_write(&slub_lock);
  3338. return s;
  3339. }
  3340. n = kstrdup(name, GFP_KERNEL);
  3341. if (!n)
  3342. goto err;
  3343. s = kmalloc(kmem_size, GFP_KERNEL);
  3344. if (s) {
  3345. if (kmem_cache_open(s, n,
  3346. size, align, flags, ctor)) {
  3347. list_add(&s->list, &slab_caches);
  3348. up_write(&slub_lock);
  3349. if (sysfs_slab_add(s)) {
  3350. down_write(&slub_lock);
  3351. list_del(&s->list);
  3352. kfree(n);
  3353. kfree(s);
  3354. goto err;
  3355. }
  3356. return s;
  3357. }
  3358. kfree(n);
  3359. kfree(s);
  3360. }
  3361. err:
  3362. up_write(&slub_lock);
  3363. if (flags & SLAB_PANIC)
  3364. panic("Cannot create slabcache %s\n", name);
  3365. else
  3366. s = NULL;
  3367. return s;
  3368. }
  3369. EXPORT_SYMBOL(kmem_cache_create);
  3370. #ifdef CONFIG_SMP
  3371. /*
  3372. * Use the cpu notifier to insure that the cpu slabs are flushed when
  3373. * necessary.
  3374. */
  3375. static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
  3376. unsigned long action, void *hcpu)
  3377. {
  3378. long cpu = (long)hcpu;
  3379. struct kmem_cache *s;
  3380. unsigned long flags;
  3381. switch (action) {
  3382. case CPU_UP_CANCELED:
  3383. case CPU_UP_CANCELED_FROZEN:
  3384. case CPU_DEAD:
  3385. case CPU_DEAD_FROZEN:
  3386. down_read(&slub_lock);
  3387. list_for_each_entry(s, &slab_caches, list) {
  3388. local_irq_save(flags);
  3389. __flush_cpu_slab(s, cpu);
  3390. local_irq_restore(flags);
  3391. }
  3392. up_read(&slub_lock);
  3393. break;
  3394. default:
  3395. break;
  3396. }
  3397. return NOTIFY_OK;
  3398. }
  3399. static struct notifier_block __cpuinitdata slab_notifier = {
  3400. .notifier_call = slab_cpuup_callback
  3401. };
  3402. #endif
  3403. void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
  3404. {
  3405. struct kmem_cache *s;
  3406. void *ret;
  3407. if (unlikely(size > SLUB_MAX_SIZE))
  3408. return kmalloc_large(size, gfpflags);
  3409. s = get_slab(size, gfpflags);
  3410. if (unlikely(ZERO_OR_NULL_PTR(s)))
  3411. return s;
  3412. ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, caller);
  3413. /* Honor the call site pointer we received. */
  3414. trace_kmalloc(caller, ret, size, s->size, gfpflags);
  3415. return ret;
  3416. }
  3417. #ifdef CONFIG_NUMA
  3418. void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
  3419. int node, unsigned long caller)
  3420. {
  3421. struct kmem_cache *s;
  3422. void *ret;
  3423. if (unlikely(size > SLUB_MAX_SIZE)) {
  3424. ret = kmalloc_large_node(size, gfpflags, node);
  3425. trace_kmalloc_node(caller, ret,
  3426. size, PAGE_SIZE << get_order(size),
  3427. gfpflags, node);
  3428. return ret;
  3429. }
  3430. s = get_slab(size, gfpflags);
  3431. if (unlikely(ZERO_OR_NULL_PTR(s)))
  3432. return s;
  3433. ret = slab_alloc(s, gfpflags, node, caller);
  3434. /* Honor the call site pointer we received. */
  3435. trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
  3436. return ret;
  3437. }
  3438. #endif
  3439. #ifdef CONFIG_SYSFS
  3440. static int count_inuse(struct page *page)
  3441. {
  3442. return page->inuse;
  3443. }
  3444. static int count_total(struct page *page)
  3445. {
  3446. return page->objects;
  3447. }
  3448. #endif
  3449. #ifdef CONFIG_SLUB_DEBUG
  3450. static int validate_slab(struct kmem_cache *s, struct page *page,
  3451. unsigned long *map)
  3452. {
  3453. void *p;
  3454. void *addr = page_address(page);
  3455. if (!check_slab(s, page) ||
  3456. !on_freelist(s, page, NULL))
  3457. return 0;
  3458. /* Now we know that a valid freelist exists */
  3459. bitmap_zero(map, page->objects);
  3460. get_map(s, page, map);
  3461. for_each_object(p, s, addr, page->objects) {
  3462. if (test_bit(slab_index(p, s, addr), map))
  3463. if (!check_object(s, page, p, SLUB_RED_INACTIVE))
  3464. return 0;
  3465. }
  3466. for_each_object(p, s, addr, page->objects)
  3467. if (!test_bit(slab_index(p, s, addr), map))
  3468. if (!check_object(s, page, p, SLUB_RED_ACTIVE))
  3469. return 0;
  3470. return 1;
  3471. }
  3472. static void validate_slab_slab(struct kmem_cache *s, struct page *page,
  3473. unsigned long *map)
  3474. {
  3475. slab_lock(page);
  3476. validate_slab(s, page, map);
  3477. slab_unlock(page);
  3478. }
  3479. static int validate_slab_node(struct kmem_cache *s,
  3480. struct kmem_cache_node *n, unsigned long *map)
  3481. {
  3482. unsigned long count = 0;
  3483. struct page *page;
  3484. unsigned long flags;
  3485. spin_lock_irqsave(&n->list_lock, flags);
  3486. list_for_each_entry(page, &n->partial, lru) {
  3487. validate_slab_slab(s, page, map);
  3488. count++;
  3489. }
  3490. if (count != n->nr_partial)
  3491. printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
  3492. "counter=%ld\n", s->name, count, n->nr_partial);
  3493. if (!(s->flags & SLAB_STORE_USER))
  3494. goto out;
  3495. list_for_each_entry(page, &n->full, lru) {
  3496. validate_slab_slab(s, page, map);
  3497. count++;
  3498. }
  3499. if (count != atomic_long_read(&n->nr_slabs))
  3500. printk(KERN_ERR "SLUB: %s %ld slabs counted but "
  3501. "counter=%ld\n", s->name, count,
  3502. atomic_long_read(&n->nr_slabs));
  3503. out:
  3504. spin_unlock_irqrestore(&n->list_lock, flags);
  3505. return count;
  3506. }
  3507. static long validate_slab_cache(struct kmem_cache *s)
  3508. {
  3509. int node;
  3510. unsigned long count = 0;
  3511. unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
  3512. sizeof(unsigned long), GFP_KERNEL);
  3513. if (!map)
  3514. return -ENOMEM;
  3515. flush_all(s);
  3516. for_each_node_state(node, N_NORMAL_MEMORY) {
  3517. struct kmem_cache_node *n = get_node(s, node);
  3518. count += validate_slab_node(s, n, map);
  3519. }
  3520. kfree(map);
  3521. return count;
  3522. }
  3523. /*
  3524. * Generate lists of code addresses where slabcache objects are allocated
  3525. * and freed.
  3526. */
  3527. struct location {
  3528. unsigned long count;
  3529. unsigned long addr;
  3530. long long sum_time;
  3531. long min_time;
  3532. long max_time;
  3533. long min_pid;
  3534. long max_pid;
  3535. DECLARE_BITMAP(cpus, NR_CPUS);
  3536. nodemask_t nodes;
  3537. };
  3538. struct loc_track {
  3539. unsigned long max;
  3540. unsigned long count;
  3541. struct location *loc;
  3542. };
  3543. static void free_loc_track(struct loc_track *t)
  3544. {
  3545. if (t->max)
  3546. free_pages((unsigned long)t->loc,
  3547. get_order(sizeof(struct location) * t->max));
  3548. }
  3549. static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
  3550. {
  3551. struct location *l;
  3552. int order;
  3553. order = get_order(sizeof(struct location) * max);
  3554. l = (void *)__get_free_pages(flags, order);
  3555. if (!l)
  3556. return 0;
  3557. if (t->count) {
  3558. memcpy(l, t->loc, sizeof(struct location) * t->count);
  3559. free_loc_track(t);
  3560. }
  3561. t->max = max;
  3562. t->loc = l;
  3563. return 1;
  3564. }
  3565. static int add_location(struct loc_track *t, struct kmem_cache *s,
  3566. const struct track *track)
  3567. {
  3568. long start, end, pos;
  3569. struct location *l;
  3570. unsigned long caddr;
  3571. unsigned long age = jiffies - track->when;
  3572. start = -1;
  3573. end = t->count;
  3574. for ( ; ; ) {
  3575. pos = start + (end - start + 1) / 2;
  3576. /*
  3577. * There is nothing at "end". If we end up there
  3578. * we need to add something to before end.
  3579. */
  3580. if (pos == end)
  3581. break;
  3582. caddr = t->loc[pos].addr;
  3583. if (track->addr == caddr) {
  3584. l = &t->loc[pos];
  3585. l->count++;
  3586. if (track->when) {
  3587. l->sum_time += age;
  3588. if (age < l->min_time)
  3589. l->min_time = age;
  3590. if (age > l->max_time)
  3591. l->max_time = age;
  3592. if (track->pid < l->min_pid)
  3593. l->min_pid = track->pid;
  3594. if (track->pid > l->max_pid)
  3595. l->max_pid = track->pid;
  3596. cpumask_set_cpu(track->cpu,
  3597. to_cpumask(l->cpus));
  3598. }
  3599. node_set(page_to_nid(virt_to_page(track)), l->nodes);
  3600. return 1;
  3601. }
  3602. if (track->addr < caddr)
  3603. end = pos;
  3604. else
  3605. start = pos;
  3606. }
  3607. /*
  3608. * Not found. Insert new tracking element.
  3609. */
  3610. if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
  3611. return 0;
  3612. l = t->loc + pos;
  3613. if (pos < t->count)
  3614. memmove(l + 1, l,
  3615. (t->count - pos) * sizeof(struct location));
  3616. t->count++;
  3617. l->count = 1;
  3618. l->addr = track->addr;
  3619. l->sum_time = age;
  3620. l->min_time = age;
  3621. l->max_time = age;
  3622. l->min_pid = track->pid;
  3623. l->max_pid = track->pid;
  3624. cpumask_clear(to_cpumask(l->cpus));
  3625. cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
  3626. nodes_clear(l->nodes);
  3627. node_set(page_to_nid(virt_to_page(track)), l->nodes);
  3628. return 1;
  3629. }
  3630. static void process_slab(struct loc_track *t, struct kmem_cache *s,
  3631. struct page *page, enum track_item alloc,
  3632. unsigned long *map)
  3633. {
  3634. void *addr = page_address(page);
  3635. void *p;
  3636. bitmap_zero(map, page->objects);
  3637. get_map(s, page, map);
  3638. for_each_object(p, s, addr, page->objects)
  3639. if (!test_bit(slab_index(p, s, addr), map))
  3640. add_location(t, s, get_track(s, p, alloc));
  3641. }
  3642. static int list_locations(struct kmem_cache *s, char *buf,
  3643. enum track_item alloc)
  3644. {
  3645. int len = 0;
  3646. unsigned long i;
  3647. struct loc_track t = { 0, 0, NULL };
  3648. int node;
  3649. unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
  3650. sizeof(unsigned long), GFP_KERNEL);
  3651. if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
  3652. GFP_TEMPORARY)) {
  3653. kfree(map);
  3654. return sprintf(buf, "Out of memory\n");
  3655. }
  3656. /* Push back cpu slabs */
  3657. flush_all(s);
  3658. for_each_node_state(node, N_NORMAL_MEMORY) {
  3659. struct kmem_cache_node *n = get_node(s, node);
  3660. unsigned long flags;
  3661. struct page *page;
  3662. if (!atomic_long_read(&n->nr_slabs))
  3663. continue;
  3664. spin_lock_irqsave(&n->list_lock, flags);
  3665. list_for_each_entry(page, &n->partial, lru)
  3666. process_slab(&t, s, page, alloc, map);
  3667. list_for_each_entry(page, &n->full, lru)
  3668. process_slab(&t, s, page, alloc, map);
  3669. spin_unlock_irqrestore(&n->list_lock, flags);
  3670. }
  3671. for (i = 0; i < t.count; i++) {
  3672. struct location *l = &t.loc[i];
  3673. if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
  3674. break;
  3675. len += sprintf(buf + len, "%7ld ", l->count);
  3676. if (l->addr)
  3677. len += sprintf(buf + len, "%pS", (void *)l->addr);
  3678. else
  3679. len += sprintf(buf + len, "<not-available>");
  3680. if (l->sum_time != l->min_time) {
  3681. len += sprintf(buf + len, " age=%ld/%ld/%ld",
  3682. l->min_time,
  3683. (long)div_u64(l->sum_time, l->count),
  3684. l->max_time);
  3685. } else
  3686. len += sprintf(buf + len, " age=%ld",
  3687. l->min_time);
  3688. if (l->min_pid != l->max_pid)
  3689. len += sprintf(buf + len, " pid=%ld-%ld",
  3690. l->min_pid, l->max_pid);
  3691. else
  3692. len += sprintf(buf + len, " pid=%ld",
  3693. l->min_pid);
  3694. if (num_online_cpus() > 1 &&
  3695. !cpumask_empty(to_cpumask(l->cpus)) &&
  3696. len < PAGE_SIZE - 60) {
  3697. len += sprintf(buf + len, " cpus=");
  3698. len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
  3699. to_cpumask(l->cpus));
  3700. }
  3701. if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
  3702. len < PAGE_SIZE - 60) {
  3703. len += sprintf(buf + len, " nodes=");
  3704. len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
  3705. l->nodes);
  3706. }
  3707. len += sprintf(buf + len, "\n");
  3708. }
  3709. free_loc_track(&t);
  3710. kfree(map);
  3711. if (!t.count)
  3712. len += sprintf(buf, "No data\n");
  3713. return len;
  3714. }
  3715. #endif
  3716. #ifdef SLUB_RESILIENCY_TEST
  3717. static void resiliency_test(void)
  3718. {
  3719. u8 *p;
  3720. BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
  3721. printk(KERN_ERR "SLUB resiliency testing\n");
  3722. printk(KERN_ERR "-----------------------\n");
  3723. printk(KERN_ERR "A. Corruption after allocation\n");
  3724. p = kzalloc(16, GFP_KERNEL);
  3725. p[16] = 0x12;
  3726. printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
  3727. " 0x12->0x%p\n\n", p + 16);
  3728. validate_slab_cache(kmalloc_caches[4]);
  3729. /* Hmmm... The next two are dangerous */
  3730. p = kzalloc(32, GFP_KERNEL);
  3731. p[32 + sizeof(void *)] = 0x34;
  3732. printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
  3733. " 0x34 -> -0x%p\n", p);
  3734. printk(KERN_ERR
  3735. "If allocated object is overwritten then not detectable\n\n");
  3736. validate_slab_cache(kmalloc_caches[5]);
  3737. p = kzalloc(64, GFP_KERNEL);
  3738. p += 64 + (get_cycles() & 0xff) * sizeof(void *);
  3739. *p = 0x56;
  3740. printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
  3741. p);
  3742. printk(KERN_ERR
  3743. "If allocated object is overwritten then not detectable\n\n");
  3744. validate_slab_cache(kmalloc_caches[6]);
  3745. printk(KERN_ERR "\nB. Corruption after free\n");
  3746. p = kzalloc(128, GFP_KERNEL);
  3747. kfree(p);
  3748. *p = 0x78;
  3749. printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
  3750. validate_slab_cache(kmalloc_caches[7]);
  3751. p = kzalloc(256, GFP_KERNEL);
  3752. kfree(p);
  3753. p[50] = 0x9a;
  3754. printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
  3755. p);
  3756. validate_slab_cache(kmalloc_caches[8]);
  3757. p = kzalloc(512, GFP_KERNEL);
  3758. kfree(p);
  3759. p[512] = 0xab;
  3760. printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
  3761. validate_slab_cache(kmalloc_caches[9]);
  3762. }
  3763. #else
  3764. #ifdef CONFIG_SYSFS
  3765. static void resiliency_test(void) {};
  3766. #endif
  3767. #endif
  3768. #ifdef CONFIG_SYSFS
  3769. enum slab_stat_type {
  3770. SL_ALL, /* All slabs */
  3771. SL_PARTIAL, /* Only partially allocated slabs */
  3772. SL_CPU, /* Only slabs used for cpu caches */
  3773. SL_OBJECTS, /* Determine allocated objects not slabs */
  3774. SL_TOTAL /* Determine object capacity not slabs */
  3775. };
  3776. #define SO_ALL (1 << SL_ALL)
  3777. #define SO_PARTIAL (1 << SL_PARTIAL)
  3778. #define SO_CPU (1 << SL_CPU)
  3779. #define SO_OBJECTS (1 << SL_OBJECTS)
  3780. #define SO_TOTAL (1 << SL_TOTAL)
  3781. static ssize_t show_slab_objects(struct kmem_cache *s,
  3782. char *buf, unsigned long flags)
  3783. {
  3784. unsigned long total = 0;
  3785. int node;
  3786. int x;
  3787. unsigned long *nodes;
  3788. unsigned long *per_cpu;
  3789. nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
  3790. if (!nodes)
  3791. return -ENOMEM;
  3792. per_cpu = nodes + nr_node_ids;
  3793. if (flags & SO_CPU) {
  3794. int cpu;
  3795. for_each_possible_cpu(cpu) {
  3796. struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
  3797. int node = ACCESS_ONCE(c->node);
  3798. struct page *page;
  3799. if (node < 0)
  3800. continue;
  3801. page = ACCESS_ONCE(c->page);
  3802. if (page) {
  3803. if (flags & SO_TOTAL)
  3804. x = page->objects;
  3805. else if (flags & SO_OBJECTS)
  3806. x = page->inuse;
  3807. else
  3808. x = 1;
  3809. total += x;
  3810. nodes[node] += x;
  3811. }
  3812. page = c->partial;
  3813. if (page) {
  3814. node = page_to_nid(page);
  3815. if (flags & SO_TOTAL)
  3816. WARN_ON_ONCE(1);
  3817. else if (flags & SO_OBJECTS)
  3818. WARN_ON_ONCE(1);
  3819. else
  3820. x = page->pages;
  3821. total += x;
  3822. nodes[node] += x;
  3823. }
  3824. per_cpu[node]++;
  3825. }
  3826. }
  3827. lock_memory_hotplug();
  3828. #ifdef CONFIG_SLUB_DEBUG
  3829. if (flags & SO_ALL) {
  3830. for_each_node_state(node, N_NORMAL_MEMORY) {
  3831. struct kmem_cache_node *n = get_node(s, node);
  3832. if (flags & SO_TOTAL)
  3833. x = atomic_long_read(&n->total_objects);
  3834. else if (flags & SO_OBJECTS)
  3835. x = atomic_long_read(&n->total_objects) -
  3836. count_partial(n, count_free);
  3837. else
  3838. x = atomic_long_read(&n->nr_slabs);
  3839. total += x;
  3840. nodes[node] += x;
  3841. }
  3842. } else
  3843. #endif
  3844. if (flags & SO_PARTIAL) {
  3845. for_each_node_state(node, N_NORMAL_MEMORY) {
  3846. struct kmem_cache_node *n = get_node(s, node);
  3847. if (flags & SO_TOTAL)
  3848. x = count_partial(n, count_total);
  3849. else if (flags & SO_OBJECTS)
  3850. x = count_partial(n, count_inuse);
  3851. else
  3852. x = n->nr_partial;
  3853. total += x;
  3854. nodes[node] += x;
  3855. }
  3856. }
  3857. x = sprintf(buf, "%lu", total);
  3858. #ifdef CONFIG_NUMA
  3859. for_each_node_state(node, N_NORMAL_MEMORY)
  3860. if (nodes[node])
  3861. x += sprintf(buf + x, " N%d=%lu",
  3862. node, nodes[node]);
  3863. #endif
  3864. unlock_memory_hotplug();
  3865. kfree(nodes);
  3866. return x + sprintf(buf + x, "\n");
  3867. }
  3868. #ifdef CONFIG_SLUB_DEBUG
  3869. static int any_slab_objects(struct kmem_cache *s)
  3870. {
  3871. int node;
  3872. for_each_online_node(node) {
  3873. struct kmem_cache_node *n = get_node(s, node);
  3874. if (!n)
  3875. continue;
  3876. if (atomic_long_read(&n->total_objects))
  3877. return 1;
  3878. }
  3879. return 0;
  3880. }
  3881. #endif
  3882. #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
  3883. #define to_slab(n) container_of(n, struct kmem_cache, kobj)
  3884. struct slab_attribute {
  3885. struct attribute attr;
  3886. ssize_t (*show)(struct kmem_cache *s, char *buf);
  3887. ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
  3888. };
  3889. #define SLAB_ATTR_RO(_name) \
  3890. static struct slab_attribute _name##_attr = \
  3891. __ATTR(_name, 0400, _name##_show, NULL)
  3892. #define SLAB_ATTR(_name) \
  3893. static struct slab_attribute _name##_attr = \
  3894. __ATTR(_name, 0600, _name##_show, _name##_store)
  3895. static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
  3896. {
  3897. return sprintf(buf, "%d\n", s->size);
  3898. }
  3899. SLAB_ATTR_RO(slab_size);
  3900. static ssize_t align_show(struct kmem_cache *s, char *buf)
  3901. {
  3902. return sprintf(buf, "%d\n", s->align);
  3903. }
  3904. SLAB_ATTR_RO(align);
  3905. static ssize_t object_size_show(struct kmem_cache *s, char *buf)
  3906. {
  3907. return sprintf(buf, "%d\n", s->objsize);
  3908. }
  3909. SLAB_ATTR_RO(object_size);
  3910. static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
  3911. {
  3912. return sprintf(buf, "%d\n", oo_objects(s->oo));
  3913. }
  3914. SLAB_ATTR_RO(objs_per_slab);
  3915. static ssize_t order_store(struct kmem_cache *s,
  3916. const char *buf, size_t length)
  3917. {
  3918. unsigned long order;
  3919. int err;
  3920. err = strict_strtoul(buf, 10, &order);
  3921. if (err)
  3922. return err;
  3923. if (order > slub_max_order || order < slub_min_order)
  3924. return -EINVAL;
  3925. calculate_sizes(s, order);
  3926. return length;
  3927. }
  3928. static ssize_t order_show(struct kmem_cache *s, char *buf)
  3929. {
  3930. return sprintf(buf, "%d\n", oo_order(s->oo));
  3931. }
  3932. SLAB_ATTR(order);
  3933. static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
  3934. {
  3935. return sprintf(buf, "%lu\n", s->min_partial);
  3936. }
  3937. static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
  3938. size_t length)
  3939. {
  3940. unsigned long min;
  3941. int err;
  3942. err = strict_strtoul(buf, 10, &min);
  3943. if (err)
  3944. return err;
  3945. set_min_partial(s, min);
  3946. return length;
  3947. }
  3948. SLAB_ATTR(min_partial);
  3949. static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
  3950. {
  3951. return sprintf(buf, "%u\n", s->cpu_partial);
  3952. }
  3953. static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
  3954. size_t length)
  3955. {
  3956. unsigned long objects;
  3957. int err;
  3958. err = strict_strtoul(buf, 10, &objects);
  3959. if (err)
  3960. return err;
  3961. if (objects && kmem_cache_debug(s))
  3962. return -EINVAL;
  3963. s->cpu_partial = objects;
  3964. flush_all(s);
  3965. return length;
  3966. }
  3967. SLAB_ATTR(cpu_partial);
  3968. static ssize_t ctor_show(struct kmem_cache *s, char *buf)
  3969. {
  3970. if (!s->ctor)
  3971. return 0;
  3972. return sprintf(buf, "%pS\n", s->ctor);
  3973. }
  3974. SLAB_ATTR_RO(ctor);
  3975. static ssize_t aliases_show(struct kmem_cache *s, char *buf)
  3976. {
  3977. return sprintf(buf, "%d\n", s->refcount - 1);
  3978. }
  3979. SLAB_ATTR_RO(aliases);
  3980. static ssize_t partial_show(struct kmem_cache *s, char *buf)
  3981. {
  3982. return show_slab_objects(s, buf, SO_PARTIAL);
  3983. }
  3984. SLAB_ATTR_RO(partial);
  3985. static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
  3986. {
  3987. return show_slab_objects(s, buf, SO_CPU);
  3988. }
  3989. SLAB_ATTR_RO(cpu_slabs);
  3990. static ssize_t objects_show(struct kmem_cache *s, char *buf)
  3991. {
  3992. return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
  3993. }
  3994. SLAB_ATTR_RO(objects);
  3995. static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
  3996. {
  3997. return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
  3998. }
  3999. SLAB_ATTR_RO(objects_partial);
  4000. static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
  4001. {
  4002. int objects = 0;
  4003. int pages = 0;
  4004. int cpu;
  4005. int len;
  4006. for_each_online_cpu(cpu) {
  4007. struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
  4008. if (page) {
  4009. pages += page->pages;
  4010. objects += page->pobjects;
  4011. }
  4012. }
  4013. len = sprintf(buf, "%d(%d)", objects, pages);
  4014. #ifdef CONFIG_SMP
  4015. for_each_online_cpu(cpu) {
  4016. struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
  4017. if (page && len < PAGE_SIZE - 20)
  4018. len += sprintf(buf + len, " C%d=%d(%d)", cpu,
  4019. page->pobjects, page->pages);
  4020. }
  4021. #endif
  4022. return len + sprintf(buf + len, "\n");
  4023. }
  4024. SLAB_ATTR_RO(slabs_cpu_partial);
  4025. static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
  4026. {
  4027. return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
  4028. }
  4029. static ssize_t reclaim_account_store(struct kmem_cache *s,
  4030. const char *buf, size_t length)
  4031. {
  4032. s->flags &= ~SLAB_RECLAIM_ACCOUNT;
  4033. if (buf[0] == '1')
  4034. s->flags |= SLAB_RECLAIM_ACCOUNT;
  4035. return length;
  4036. }
  4037. SLAB_ATTR(reclaim_account);
  4038. static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
  4039. {
  4040. return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
  4041. }
  4042. SLAB_ATTR_RO(hwcache_align);
  4043. #ifdef CONFIG_ZONE_DMA
  4044. static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
  4045. {
  4046. return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
  4047. }
  4048. SLAB_ATTR_RO(cache_dma);
  4049. #endif
  4050. static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
  4051. {
  4052. return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
  4053. }
  4054. SLAB_ATTR_RO(destroy_by_rcu);
  4055. static ssize_t reserved_show(struct kmem_cache *s, char *buf)
  4056. {
  4057. return sprintf(buf, "%d\n", s->reserved);
  4058. }
  4059. SLAB_ATTR_RO(reserved);
  4060. #ifdef CONFIG_SLUB_DEBUG
  4061. static ssize_t slabs_show(struct kmem_cache *s, char *buf)
  4062. {
  4063. return show_slab_objects(s, buf, SO_ALL);
  4064. }
  4065. SLAB_ATTR_RO(slabs);
  4066. static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
  4067. {
  4068. return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
  4069. }
  4070. SLAB_ATTR_RO(total_objects);
  4071. static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
  4072. {
  4073. return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
  4074. }
  4075. static ssize_t sanity_checks_store(struct kmem_cache *s,
  4076. const char *buf, size_t length)
  4077. {
  4078. s->flags &= ~SLAB_DEBUG_FREE;
  4079. if (buf[0] == '1') {
  4080. s->flags &= ~__CMPXCHG_DOUBLE;
  4081. s->flags |= SLAB_DEBUG_FREE;
  4082. }
  4083. return length;
  4084. }
  4085. SLAB_ATTR(sanity_checks);
  4086. static ssize_t trace_show(struct kmem_cache *s, char *buf)
  4087. {
  4088. return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
  4089. }
  4090. static ssize_t trace_store(struct kmem_cache *s, const char *buf,
  4091. size_t length)
  4092. {
  4093. s->flags &= ~SLAB_TRACE;
  4094. if (buf[0] == '1') {
  4095. s->flags &= ~__CMPXCHG_DOUBLE;
  4096. s->flags |= SLAB_TRACE;
  4097. }
  4098. return length;
  4099. }
  4100. SLAB_ATTR(trace);
  4101. static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
  4102. {
  4103. return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
  4104. }
  4105. static ssize_t red_zone_store(struct kmem_cache *s,
  4106. const char *buf, size_t length)
  4107. {
  4108. if (any_slab_objects(s))
  4109. return -EBUSY;
  4110. s->flags &= ~SLAB_RED_ZONE;
  4111. if (buf[0] == '1') {
  4112. s->flags &= ~__CMPXCHG_DOUBLE;
  4113. s->flags |= SLAB_RED_ZONE;
  4114. }
  4115. calculate_sizes(s, -1);
  4116. return length;
  4117. }
  4118. SLAB_ATTR(red_zone);
  4119. static ssize_t poison_show(struct kmem_cache *s, char *buf)
  4120. {
  4121. return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
  4122. }
  4123. static ssize_t poison_store(struct kmem_cache *s,
  4124. const char *buf, size_t length)
  4125. {
  4126. if (any_slab_objects(s))
  4127. return -EBUSY;
  4128. s->flags &= ~SLAB_POISON;
  4129. if (buf[0] == '1') {
  4130. s->flags &= ~__CMPXCHG_DOUBLE;
  4131. s->flags |= SLAB_POISON;
  4132. }
  4133. calculate_sizes(s, -1);
  4134. return length;
  4135. }
  4136. SLAB_ATTR(poison);
  4137. static ssize_t store_user_show(struct kmem_cache *s, char *buf)
  4138. {
  4139. return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
  4140. }
  4141. static ssize_t store_user_store(struct kmem_cache *s,
  4142. const char *buf, size_t length)
  4143. {
  4144. if (any_slab_objects(s))
  4145. return -EBUSY;
  4146. s->flags &= ~SLAB_STORE_USER;
  4147. if (buf[0] == '1') {
  4148. s->flags &= ~__CMPXCHG_DOUBLE;
  4149. s->flags |= SLAB_STORE_USER;
  4150. }
  4151. calculate_sizes(s, -1);
  4152. return length;
  4153. }
  4154. SLAB_ATTR(store_user);
  4155. static ssize_t validate_show(struct kmem_cache *s, char *buf)
  4156. {
  4157. return 0;
  4158. }
  4159. static ssize_t validate_store(struct kmem_cache *s,
  4160. const char *buf, size_t length)
  4161. {
  4162. int ret = -EINVAL;
  4163. if (buf[0] == '1') {
  4164. ret = validate_slab_cache(s);
  4165. if (ret >= 0)
  4166. ret = length;
  4167. }
  4168. return ret;
  4169. }
  4170. SLAB_ATTR(validate);
  4171. static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
  4172. {
  4173. if (!(s->flags & SLAB_STORE_USER))
  4174. return -ENOSYS;
  4175. return list_locations(s, buf, TRACK_ALLOC);
  4176. }
  4177. SLAB_ATTR_RO(alloc_calls);
  4178. static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
  4179. {
  4180. if (!(s->flags & SLAB_STORE_USER))
  4181. return -ENOSYS;
  4182. return list_locations(s, buf, TRACK_FREE);
  4183. }
  4184. SLAB_ATTR_RO(free_calls);
  4185. #endif /* CONFIG_SLUB_DEBUG */
  4186. #ifdef CONFIG_FAILSLAB
  4187. static ssize_t failslab_show(struct kmem_cache *s, char *buf)
  4188. {
  4189. return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
  4190. }
  4191. static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
  4192. size_t length)
  4193. {
  4194. s->flags &= ~SLAB_FAILSLAB;
  4195. if (buf[0] == '1')
  4196. s->flags |= SLAB_FAILSLAB;
  4197. return length;
  4198. }
  4199. SLAB_ATTR(failslab);
  4200. #endif
  4201. static ssize_t shrink_show(struct kmem_cache *s, char *buf)
  4202. {
  4203. return 0;
  4204. }
  4205. static ssize_t shrink_store(struct kmem_cache *s,
  4206. const char *buf, size_t length)
  4207. {
  4208. if (buf[0] == '1') {
  4209. int rc = kmem_cache_shrink(s);
  4210. if (rc)
  4211. return rc;
  4212. } else
  4213. return -EINVAL;
  4214. return length;
  4215. }
  4216. SLAB_ATTR(shrink);
  4217. #ifdef CONFIG_NUMA
  4218. static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
  4219. {
  4220. return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
  4221. }
  4222. static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
  4223. const char *buf, size_t length)
  4224. {
  4225. unsigned long ratio;
  4226. int err;
  4227. err = strict_strtoul(buf, 10, &ratio);
  4228. if (err)
  4229. return err;
  4230. if (ratio <= 100)
  4231. s->remote_node_defrag_ratio = ratio * 10;
  4232. return length;
  4233. }
  4234. SLAB_ATTR(remote_node_defrag_ratio);
  4235. #endif
  4236. #ifdef CONFIG_SLUB_STATS
  4237. static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
  4238. {
  4239. unsigned long sum = 0;
  4240. int cpu;
  4241. int len;
  4242. int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
  4243. if (!data)
  4244. return -ENOMEM;
  4245. for_each_online_cpu(cpu) {
  4246. unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
  4247. data[cpu] = x;
  4248. sum += x;
  4249. }
  4250. len = sprintf(buf, "%lu", sum);
  4251. #ifdef CONFIG_SMP
  4252. for_each_online_cpu(cpu) {
  4253. if (data[cpu] && len < PAGE_SIZE - 20)
  4254. len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
  4255. }
  4256. #endif
  4257. kfree(data);
  4258. return len + sprintf(buf + len, "\n");
  4259. }
  4260. static void clear_stat(struct kmem_cache *s, enum stat_item si)
  4261. {
  4262. int cpu;
  4263. for_each_online_cpu(cpu)
  4264. per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
  4265. }
  4266. #define STAT_ATTR(si, text) \
  4267. static ssize_t text##_show(struct kmem_cache *s, char *buf) \
  4268. { \
  4269. return show_stat(s, buf, si); \
  4270. } \
  4271. static ssize_t text##_store(struct kmem_cache *s, \
  4272. const char *buf, size_t length) \
  4273. { \
  4274. if (buf[0] != '0') \
  4275. return -EINVAL; \
  4276. clear_stat(s, si); \
  4277. return length; \
  4278. } \
  4279. SLAB_ATTR(text); \
  4280. STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
  4281. STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
  4282. STAT_ATTR(FREE_FASTPATH, free_fastpath);
  4283. STAT_ATTR(FREE_SLOWPATH, free_slowpath);
  4284. STAT_ATTR(FREE_FROZEN, free_frozen);
  4285. STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
  4286. STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
  4287. STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
  4288. STAT_ATTR(ALLOC_SLAB, alloc_slab);
  4289. STAT_ATTR(ALLOC_REFILL, alloc_refill);
  4290. STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
  4291. STAT_ATTR(FREE_SLAB, free_slab);
  4292. STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
  4293. STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
  4294. STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
  4295. STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
  4296. STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
  4297. STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
  4298. STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
  4299. STAT_ATTR(ORDER_FALLBACK, order_fallback);
  4300. STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
  4301. STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
  4302. STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
  4303. STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
  4304. STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
  4305. STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
  4306. #endif
  4307. static struct attribute *slab_attrs[] = {
  4308. &slab_size_attr.attr,
  4309. &object_size_attr.attr,
  4310. &objs_per_slab_attr.attr,
  4311. &order_attr.attr,
  4312. &min_partial_attr.attr,
  4313. &cpu_partial_attr.attr,
  4314. &objects_attr.attr,
  4315. &objects_partial_attr.attr,
  4316. &partial_attr.attr,
  4317. &cpu_slabs_attr.attr,
  4318. &ctor_attr.attr,
  4319. &aliases_attr.attr,
  4320. &align_attr.attr,
  4321. &hwcache_align_attr.attr,
  4322. &reclaim_account_attr.attr,
  4323. &destroy_by_rcu_attr.attr,
  4324. &shrink_attr.attr,
  4325. &reserved_attr.attr,
  4326. &slabs_cpu_partial_attr.attr,
  4327. #ifdef CONFIG_SLUB_DEBUG
  4328. &total_objects_attr.attr,
  4329. &slabs_attr.attr,
  4330. &sanity_checks_attr.attr,
  4331. &trace_attr.attr,
  4332. &red_zone_attr.attr,
  4333. &poison_attr.attr,
  4334. &store_user_attr.attr,
  4335. &validate_attr.attr,
  4336. &alloc_calls_attr.attr,
  4337. &free_calls_attr.attr,
  4338. #endif
  4339. #ifdef CONFIG_ZONE_DMA
  4340. &cache_dma_attr.attr,
  4341. #endif
  4342. #ifdef CONFIG_NUMA
  4343. &remote_node_defrag_ratio_attr.attr,
  4344. #endif
  4345. #ifdef CONFIG_SLUB_STATS
  4346. &alloc_fastpath_attr.attr,
  4347. &alloc_slowpath_attr.attr,
  4348. &free_fastpath_attr.attr,
  4349. &free_slowpath_attr.attr,
  4350. &free_frozen_attr.attr,
  4351. &free_add_partial_attr.attr,
  4352. &free_remove_partial_attr.attr,
  4353. &alloc_from_partial_attr.attr,
  4354. &alloc_slab_attr.attr,
  4355. &alloc_refill_attr.attr,
  4356. &alloc_node_mismatch_attr.attr,
  4357. &free_slab_attr.attr,
  4358. &cpuslab_flush_attr.attr,
  4359. &deactivate_full_attr.attr,
  4360. &deactivate_empty_attr.attr,
  4361. &deactivate_to_head_attr.attr,
  4362. &deactivate_to_tail_attr.attr,
  4363. &deactivate_remote_frees_attr.attr,
  4364. &deactivate_bypass_attr.attr,
  4365. &order_fallback_attr.attr,
  4366. &cmpxchg_double_fail_attr.attr,
  4367. &cmpxchg_double_cpu_fail_attr.attr,
  4368. &cpu_partial_alloc_attr.attr,
  4369. &cpu_partial_free_attr.attr,
  4370. &cpu_partial_node_attr.attr,
  4371. &cpu_partial_drain_attr.attr,
  4372. #endif
  4373. #ifdef CONFIG_FAILSLAB
  4374. &failslab_attr.attr,
  4375. #endif
  4376. NULL
  4377. };
  4378. static struct attribute_group slab_attr_group = {
  4379. .attrs = slab_attrs,
  4380. };
  4381. static ssize_t slab_attr_show(struct kobject *kobj,
  4382. struct attribute *attr,
  4383. char *buf)
  4384. {
  4385. struct slab_attribute *attribute;
  4386. struct kmem_cache *s;
  4387. int err;
  4388. attribute = to_slab_attr(attr);
  4389. s = to_slab(kobj);
  4390. if (!attribute->show)
  4391. return -EIO;
  4392. err = attribute->show(s, buf);
  4393. return err;
  4394. }
  4395. static ssize_t slab_attr_store(struct kobject *kobj,
  4396. struct attribute *attr,
  4397. const char *buf, size_t len)
  4398. {
  4399. struct slab_attribute *attribute;
  4400. struct kmem_cache *s;
  4401. int err;
  4402. attribute = to_slab_attr(attr);
  4403. s = to_slab(kobj);
  4404. if (!attribute->store)
  4405. return -EIO;
  4406. err = attribute->store(s, buf, len);
  4407. return err;
  4408. }
  4409. static void kmem_cache_release(struct kobject *kobj)
  4410. {
  4411. struct kmem_cache *s = to_slab(kobj);
  4412. kfree(s->name);
  4413. kfree(s);
  4414. }
  4415. static const struct sysfs_ops slab_sysfs_ops = {
  4416. .show = slab_attr_show,
  4417. .store = slab_attr_store,
  4418. };
  4419. static struct kobj_type slab_ktype = {
  4420. .sysfs_ops = &slab_sysfs_ops,
  4421. .release = kmem_cache_release
  4422. };
  4423. static int uevent_filter(struct kset *kset, struct kobject *kobj)
  4424. {
  4425. struct kobj_type *ktype = get_ktype(kobj);
  4426. if (ktype == &slab_ktype)
  4427. return 1;
  4428. return 0;
  4429. }
  4430. static const struct kset_uevent_ops slab_uevent_ops = {
  4431. .filter = uevent_filter,
  4432. };
  4433. static struct kset *slab_kset;
  4434. #define ID_STR_LENGTH 64
  4435. /* Create a unique string id for a slab cache:
  4436. *
  4437. * Format :[flags-]size
  4438. */
  4439. static char *create_unique_id(struct kmem_cache *s)
  4440. {
  4441. char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
  4442. char *p = name;
  4443. BUG_ON(!name);
  4444. *p++ = ':';
  4445. /*
  4446. * First flags affecting slabcache operations. We will only
  4447. * get here for aliasable slabs so we do not need to support
  4448. * too many flags. The flags here must cover all flags that
  4449. * are matched during merging to guarantee that the id is
  4450. * unique.
  4451. */
  4452. if (s->flags & SLAB_CACHE_DMA)
  4453. *p++ = 'd';
  4454. if (s->flags & SLAB_RECLAIM_ACCOUNT)
  4455. *p++ = 'a';
  4456. if (s->flags & SLAB_DEBUG_FREE)
  4457. *p++ = 'F';
  4458. if (!(s->flags & SLAB_NOTRACK))
  4459. *p++ = 't';
  4460. if (p != name + 1)
  4461. *p++ = '-';
  4462. p += sprintf(p, "%07d", s->size);
  4463. BUG_ON(p > name + ID_STR_LENGTH - 1);
  4464. return name;
  4465. }
  4466. static int sysfs_slab_add(struct kmem_cache *s)
  4467. {
  4468. int err;
  4469. const char *name;
  4470. int unmergeable;
  4471. if (slab_state < SYSFS)
  4472. /* Defer until later */
  4473. return 0;
  4474. unmergeable = slab_unmergeable(s);
  4475. if (unmergeable) {
  4476. /*
  4477. * Slabcache can never be merged so we can use the name proper.
  4478. * This is typically the case for debug situations. In that
  4479. * case we can catch duplicate names easily.
  4480. */
  4481. sysfs_remove_link(&slab_kset->kobj, s->name);
  4482. name = s->name;
  4483. } else {
  4484. /*
  4485. * Create a unique name for the slab as a target
  4486. * for the symlinks.
  4487. */
  4488. name = create_unique_id(s);
  4489. }
  4490. s->kobj.kset = slab_kset;
  4491. err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
  4492. if (err) {
  4493. kobject_put(&s->kobj);
  4494. return err;
  4495. }
  4496. err = sysfs_create_group(&s->kobj, &slab_attr_group);
  4497. if (err) {
  4498. kobject_del(&s->kobj);
  4499. kobject_put(&s->kobj);
  4500. return err;
  4501. }
  4502. kobject_uevent(&s->kobj, KOBJ_ADD);
  4503. if (!unmergeable) {
  4504. /* Setup first alias */
  4505. sysfs_slab_alias(s, s->name);
  4506. kfree(name);
  4507. }
  4508. return 0;
  4509. }
  4510. static void sysfs_slab_remove(struct kmem_cache *s)
  4511. {
  4512. if (slab_state < SYSFS)
  4513. /*
  4514. * Sysfs has not been setup yet so no need to remove the
  4515. * cache from sysfs.
  4516. */
  4517. return;
  4518. kobject_uevent(&s->kobj, KOBJ_REMOVE);
  4519. kobject_del(&s->kobj);
  4520. kobject_put(&s->kobj);
  4521. }
  4522. /*
  4523. * Need to buffer aliases during bootup until sysfs becomes
  4524. * available lest we lose that information.
  4525. */
  4526. struct saved_alias {
  4527. struct kmem_cache *s;
  4528. const char *name;
  4529. struct saved_alias *next;
  4530. };
  4531. static struct saved_alias *alias_list;
  4532. static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
  4533. {
  4534. struct saved_alias *al;
  4535. if (slab_state == SYSFS) {
  4536. /*
  4537. * If we have a leftover link then remove it.
  4538. */
  4539. sysfs_remove_link(&slab_kset->kobj, name);
  4540. return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
  4541. }
  4542. al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
  4543. if (!al)
  4544. return -ENOMEM;
  4545. al->s = s;
  4546. al->name = name;
  4547. al->next = alias_list;
  4548. alias_list = al;
  4549. return 0;
  4550. }
  4551. static int __init slab_sysfs_init(void)
  4552. {
  4553. struct kmem_cache *s;
  4554. int err;
  4555. down_write(&slub_lock);
  4556. slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
  4557. if (!slab_kset) {
  4558. up_write(&slub_lock);
  4559. printk(KERN_ERR "Cannot register slab subsystem.\n");
  4560. return -ENOSYS;
  4561. }
  4562. slab_state = SYSFS;
  4563. list_for_each_entry(s, &slab_caches, list) {
  4564. err = sysfs_slab_add(s);
  4565. if (err)
  4566. printk(KERN_ERR "SLUB: Unable to add boot slab %s"
  4567. " to sysfs\n", s->name);
  4568. }
  4569. while (alias_list) {
  4570. struct saved_alias *al = alias_list;
  4571. alias_list = alias_list->next;
  4572. err = sysfs_slab_alias(al->s, al->name);
  4573. if (err)
  4574. printk(KERN_ERR "SLUB: Unable to add boot slab alias"
  4575. " %s to sysfs\n", s->name);
  4576. kfree(al);
  4577. }
  4578. up_write(&slub_lock);
  4579. resiliency_test();
  4580. return 0;
  4581. }
  4582. __initcall(slab_sysfs_init);
  4583. #endif /* CONFIG_SYSFS */
  4584. /*
  4585. * The /proc/slabinfo ABI
  4586. */
  4587. #ifdef CONFIG_SLABINFO
  4588. static void print_slabinfo_header(struct seq_file *m)
  4589. {
  4590. seq_puts(m, "slabinfo - version: 2.1\n");
  4591. seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
  4592. "<objperslab> <pagesperslab>");
  4593. seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
  4594. seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
  4595. seq_putc(m, '\n');
  4596. }
  4597. static void *s_start(struct seq_file *m, loff_t *pos)
  4598. {
  4599. loff_t n = *pos;
  4600. down_read(&slub_lock);
  4601. if (!n)
  4602. print_slabinfo_header(m);
  4603. return seq_list_start(&slab_caches, *pos);
  4604. }
  4605. static void *s_next(struct seq_file *m, void *p, loff_t *pos)
  4606. {
  4607. return seq_list_next(p, &slab_caches, pos);
  4608. }
  4609. static void s_stop(struct seq_file *m, void *p)
  4610. {
  4611. up_read(&slub_lock);
  4612. }
  4613. static int s_show(struct seq_file *m, void *p)
  4614. {
  4615. unsigned long nr_partials = 0;
  4616. unsigned long nr_slabs = 0;
  4617. unsigned long nr_inuse = 0;
  4618. unsigned long nr_objs = 0;
  4619. unsigned long nr_free = 0;
  4620. struct kmem_cache *s;
  4621. int node;
  4622. s = list_entry(p, struct kmem_cache, list);
  4623. for_each_online_node(node) {
  4624. struct kmem_cache_node *n = get_node(s, node);
  4625. if (!n)
  4626. continue;
  4627. nr_partials += n->nr_partial;
  4628. nr_slabs += atomic_long_read(&n->nr_slabs);
  4629. nr_objs += atomic_long_read(&n->total_objects);
  4630. nr_free += count_partial(n, count_free);
  4631. }
  4632. nr_inuse = nr_objs - nr_free;
  4633. seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
  4634. nr_objs, s->size, oo_objects(s->oo),
  4635. (1 << oo_order(s->oo)));
  4636. seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
  4637. seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
  4638. 0UL);
  4639. seq_putc(m, '\n');
  4640. return 0;
  4641. }
  4642. static const struct seq_operations slabinfo_op = {
  4643. .start = s_start,
  4644. .next = s_next,
  4645. .stop = s_stop,
  4646. .show = s_show,
  4647. };
  4648. static int slabinfo_open(struct inode *inode, struct file *file)
  4649. {
  4650. return seq_open(file, &slabinfo_op);
  4651. }
  4652. static const struct file_operations proc_slabinfo_operations = {
  4653. .open = slabinfo_open,
  4654. .read = seq_read,
  4655. .llseek = seq_lseek,
  4656. .release = seq_release,
  4657. };
  4658. static int __init slab_proc_init(void)
  4659. {
  4660. proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
  4661. return 0;
  4662. }
  4663. module_init(slab_proc_init);
  4664. #endif /* CONFIG_SLABINFO */