page-flags.h 20 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665
  1. /*
  2. * Macros for manipulating and testing page->flags
  3. */
  4. #ifndef PAGE_FLAGS_H
  5. #define PAGE_FLAGS_H
  6. #include <linux/types.h>
  7. #include <linux/bug.h>
  8. #include <linux/mmdebug.h>
  9. #ifndef __GENERATING_BOUNDS_H
  10. #include <linux/mm_types.h>
  11. #include <generated/bounds.h>
  12. #endif /* !__GENERATING_BOUNDS_H */
  13. /*
  14. * Various page->flags bits:
  15. *
  16. * PG_reserved is set for special pages, which can never be swapped out. Some
  17. * of them might not even exist (eg empty_bad_page)...
  18. *
  19. * The PG_private bitflag is set on pagecache pages if they contain filesystem
  20. * specific data (which is normally at page->private). It can be used by
  21. * private allocations for its own usage.
  22. *
  23. * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
  24. * and cleared when writeback _starts_ or when read _completes_. PG_writeback
  25. * is set before writeback starts and cleared when it finishes.
  26. *
  27. * PG_locked also pins a page in pagecache, and blocks truncation of the file
  28. * while it is held.
  29. *
  30. * page_waitqueue(page) is a wait queue of all tasks waiting for the page
  31. * to become unlocked.
  32. *
  33. * PG_uptodate tells whether the page's contents is valid. When a read
  34. * completes, the page becomes uptodate, unless a disk I/O error happened.
  35. *
  36. * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
  37. * file-backed pagecache (see mm/vmscan.c).
  38. *
  39. * PG_error is set to indicate that an I/O error occurred on this page.
  40. *
  41. * PG_arch_1 is an architecture specific page state bit. The generic code
  42. * guarantees that this bit is cleared for a page when it first is entered into
  43. * the page cache.
  44. *
  45. * PG_highmem pages are not permanently mapped into the kernel virtual address
  46. * space, they need to be kmapped separately for doing IO on the pages. The
  47. * struct page (these bits with information) are always mapped into kernel
  48. * address space...
  49. *
  50. * PG_hwpoison indicates that a page got corrupted in hardware and contains
  51. * data with incorrect ECC bits that triggered a machine check. Accessing is
  52. * not safe since it may cause another machine check. Don't touch!
  53. */
  54. /*
  55. * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
  56. * locked- and dirty-page accounting.
  57. *
  58. * The page flags field is split into two parts, the main flags area
  59. * which extends from the low bits upwards, and the fields area which
  60. * extends from the high bits downwards.
  61. *
  62. * | FIELD | ... | FLAGS |
  63. * N-1 ^ 0
  64. * (NR_PAGEFLAGS)
  65. *
  66. * The fields area is reserved for fields mapping zone, node (for NUMA) and
  67. * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
  68. * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
  69. */
  70. enum pageflags {
  71. PG_locked, /* Page is locked. Don't touch. */
  72. PG_error,
  73. PG_referenced,
  74. PG_uptodate,
  75. PG_dirty,
  76. PG_lru,
  77. PG_active,
  78. PG_slab,
  79. PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
  80. PG_arch_1,
  81. PG_reserved,
  82. PG_private, /* If pagecache, has fs-private data */
  83. PG_private_2, /* If pagecache, has fs aux data */
  84. PG_writeback, /* Page is under writeback */
  85. PG_head, /* A head page */
  86. PG_swapcache, /* Swap page: swp_entry_t in private */
  87. PG_mappedtodisk, /* Has blocks allocated on-disk */
  88. PG_reclaim, /* To be reclaimed asap */
  89. PG_swapbacked, /* Page is backed by RAM/swap */
  90. PG_unevictable, /* Page is "unevictable" */
  91. #ifdef CONFIG_MMU
  92. PG_mlocked, /* Page is vma mlocked */
  93. #endif
  94. #ifdef CONFIG_ARCH_USES_PG_UNCACHED
  95. PG_uncached, /* Page has been mapped as uncached */
  96. #endif
  97. #ifdef CONFIG_MEMORY_FAILURE
  98. PG_hwpoison, /* hardware poisoned page. Don't touch */
  99. #endif
  100. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  101. PG_compound_lock,
  102. #endif
  103. #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
  104. PG_young,
  105. PG_idle,
  106. #endif
  107. __NR_PAGEFLAGS,
  108. /* Filesystems */
  109. PG_checked = PG_owner_priv_1,
  110. /* Two page bits are conscripted by FS-Cache to maintain local caching
  111. * state. These bits are set on pages belonging to the netfs's inodes
  112. * when those inodes are being locally cached.
  113. */
  114. PG_fscache = PG_private_2, /* page backed by cache */
  115. /* XEN */
  116. /* Pinned in Xen as a read-only pagetable page. */
  117. PG_pinned = PG_owner_priv_1,
  118. /* Pinned as part of domain save (see xen_mm_pin_all()). */
  119. PG_savepinned = PG_dirty,
  120. /* Has a grant mapping of another (foreign) domain's page. */
  121. PG_foreign = PG_owner_priv_1,
  122. /* SLOB */
  123. PG_slob_free = PG_private,
  124. };
  125. #ifndef __GENERATING_BOUNDS_H
  126. struct page; /* forward declaration */
  127. static inline struct page *compound_head(struct page *page)
  128. {
  129. unsigned long head = READ_ONCE(page->compound_head);
  130. if (unlikely(head & 1))
  131. return (struct page *) (head - 1);
  132. return page;
  133. }
  134. static inline int PageTail(struct page *page)
  135. {
  136. return READ_ONCE(page->compound_head) & 1;
  137. }
  138. static inline int PageCompound(struct page *page)
  139. {
  140. return test_bit(PG_head, &page->flags) || PageTail(page);
  141. }
  142. /*
  143. * Page flags policies wrt compound pages
  144. *
  145. * PF_ANY:
  146. * the page flag is relevant for small, head and tail pages.
  147. *
  148. * PF_HEAD:
  149. * for compound page all operations related to the page flag applied to
  150. * head page.
  151. *
  152. * PF_NO_TAIL:
  153. * modifications of the page flag must be done on small or head pages,
  154. * checks can be done on tail pages too.
  155. *
  156. * PF_NO_COMPOUND:
  157. * the page flag is not relevant for compound pages.
  158. */
  159. #define PF_ANY(page, enforce) page
  160. #define PF_HEAD(page, enforce) compound_head(page)
  161. #define PF_NO_TAIL(page, enforce) ({ \
  162. VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
  163. compound_head(page);})
  164. #define PF_NO_COMPOUND(page, enforce) ({ \
  165. VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
  166. page;})
  167. /*
  168. * Macros to create function definitions for page flags
  169. */
  170. #define TESTPAGEFLAG(uname, lname, policy) \
  171. static inline int Page##uname(struct page *page) \
  172. { return test_bit(PG_##lname, &policy(page, 0)->flags); }
  173. #define SETPAGEFLAG(uname, lname, policy) \
  174. static inline void SetPage##uname(struct page *page) \
  175. { set_bit(PG_##lname, &policy(page, 1)->flags); }
  176. #define CLEARPAGEFLAG(uname, lname, policy) \
  177. static inline void ClearPage##uname(struct page *page) \
  178. { clear_bit(PG_##lname, &policy(page, 1)->flags); }
  179. #define __SETPAGEFLAG(uname, lname, policy) \
  180. static inline void __SetPage##uname(struct page *page) \
  181. { __set_bit(PG_##lname, &policy(page, 1)->flags); }
  182. #define __CLEARPAGEFLAG(uname, lname, policy) \
  183. static inline void __ClearPage##uname(struct page *page) \
  184. { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
  185. #define TESTSETFLAG(uname, lname, policy) \
  186. static inline int TestSetPage##uname(struct page *page) \
  187. { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
  188. #define TESTCLEARFLAG(uname, lname, policy) \
  189. static inline int TestClearPage##uname(struct page *page) \
  190. { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
  191. #define __TESTCLEARFLAG(uname, lname, policy) \
  192. static inline int __TestClearPage##uname(struct page *page) \
  193. { return __test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
  194. #define PAGEFLAG(uname, lname, policy) \
  195. TESTPAGEFLAG(uname, lname, policy) \
  196. SETPAGEFLAG(uname, lname, policy) \
  197. CLEARPAGEFLAG(uname, lname, policy)
  198. #define __PAGEFLAG(uname, lname, policy) \
  199. TESTPAGEFLAG(uname, lname, policy) \
  200. __SETPAGEFLAG(uname, lname, policy) \
  201. __CLEARPAGEFLAG(uname, lname, policy)
  202. #define TESTSCFLAG(uname, lname, policy) \
  203. TESTSETFLAG(uname, lname, policy) \
  204. TESTCLEARFLAG(uname, lname, policy)
  205. #define TESTPAGEFLAG_FALSE(uname) \
  206. static inline int Page##uname(const struct page *page) { return 0; }
  207. #define SETPAGEFLAG_NOOP(uname) \
  208. static inline void SetPage##uname(struct page *page) { }
  209. #define CLEARPAGEFLAG_NOOP(uname) \
  210. static inline void ClearPage##uname(struct page *page) { }
  211. #define __CLEARPAGEFLAG_NOOP(uname) \
  212. static inline void __ClearPage##uname(struct page *page) { }
  213. #define TESTSETFLAG_FALSE(uname) \
  214. static inline int TestSetPage##uname(struct page *page) { return 0; }
  215. #define TESTCLEARFLAG_FALSE(uname) \
  216. static inline int TestClearPage##uname(struct page *page) { return 0; }
  217. #define __TESTCLEARFLAG_FALSE(uname) \
  218. static inline int __TestClearPage##uname(struct page *page) { return 0; }
  219. #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
  220. SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
  221. #define TESTSCFLAG_FALSE(uname) \
  222. TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
  223. __PAGEFLAG(Locked, locked, PF_NO_TAIL)
  224. PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
  225. PAGEFLAG(Referenced, referenced, PF_HEAD)
  226. TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
  227. __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
  228. PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
  229. __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
  230. PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
  231. PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
  232. TESTCLEARFLAG(Active, active, PF_HEAD)
  233. __PAGEFLAG(Slab, slab, PF_NO_TAIL)
  234. __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
  235. PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
  236. /* Xen */
  237. PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
  238. TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
  239. PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
  240. PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
  241. PAGEFLAG(Reserved, reserved, PF_ANY) __CLEARPAGEFLAG(Reserved, reserved, PF_ANY)
  242. PAGEFLAG(SwapBacked, swapbacked, PF_ANY)
  243. __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
  244. __SETPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
  245. /*
  246. * Private page markings that may be used by the filesystem that owns the page
  247. * for its own purposes.
  248. * - PG_private and PG_private_2 cause releasepage() and co to be invoked
  249. */
  250. PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
  251. __CLEARPAGEFLAG(Private, private, PF_ANY)
  252. PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
  253. PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
  254. TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
  255. /*
  256. * Only test-and-set exist for PG_writeback. The unconditional operators are
  257. * risky: they bypass page accounting.
  258. */
  259. TESTPAGEFLAG(Writeback, writeback, PF_NO_COMPOUND)
  260. TESTSCFLAG(Writeback, writeback, PF_NO_COMPOUND)
  261. PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_COMPOUND)
  262. /* PG_readahead is only used for reads; PG_reclaim is only for writes */
  263. PAGEFLAG(Reclaim, reclaim, PF_NO_COMPOUND)
  264. TESTCLEARFLAG(Reclaim, reclaim, PF_NO_COMPOUND)
  265. PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
  266. TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
  267. #ifdef CONFIG_HIGHMEM
  268. /*
  269. * Must use a macro here due to header dependency issues. page_zone() is not
  270. * available at this point.
  271. */
  272. #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
  273. #else
  274. PAGEFLAG_FALSE(HighMem)
  275. #endif
  276. #ifdef CONFIG_SWAP
  277. PAGEFLAG(SwapCache, swapcache, PF_ANY)
  278. #else
  279. PAGEFLAG_FALSE(SwapCache)
  280. #endif
  281. PAGEFLAG(Unevictable, unevictable, PF_HEAD)
  282. __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
  283. TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
  284. #ifdef CONFIG_MMU
  285. PAGEFLAG(Mlocked, mlocked, PF_ANY) __CLEARPAGEFLAG(Mlocked, mlocked, PF_ANY)
  286. TESTSCFLAG(Mlocked, mlocked, PF_ANY) __TESTCLEARFLAG(Mlocked, mlocked, PF_ANY)
  287. #else
  288. PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
  289. TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
  290. #endif
  291. #ifdef CONFIG_ARCH_USES_PG_UNCACHED
  292. PAGEFLAG(Uncached, uncached, PF_ANY)
  293. #else
  294. PAGEFLAG_FALSE(Uncached)
  295. #endif
  296. #ifdef CONFIG_MEMORY_FAILURE
  297. PAGEFLAG(HWPoison, hwpoison, PF_ANY)
  298. TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
  299. #define __PG_HWPOISON (1UL << PG_hwpoison)
  300. #else
  301. PAGEFLAG_FALSE(HWPoison)
  302. #define __PG_HWPOISON 0
  303. #endif
  304. #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
  305. TESTPAGEFLAG(Young, young, PF_ANY)
  306. SETPAGEFLAG(Young, young, PF_ANY)
  307. TESTCLEARFLAG(Young, young, PF_ANY)
  308. PAGEFLAG(Idle, idle, PF_ANY)
  309. #endif
  310. /*
  311. * On an anonymous page mapped into a user virtual memory area,
  312. * page->mapping points to its anon_vma, not to a struct address_space;
  313. * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
  314. *
  315. * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
  316. * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit;
  317. * and then page->mapping points, not to an anon_vma, but to a private
  318. * structure which KSM associates with that merged page. See ksm.h.
  319. *
  320. * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used.
  321. *
  322. * Please note that, confusingly, "page_mapping" refers to the inode
  323. * address_space which maps the page from disk; whereas "page_mapped"
  324. * refers to user virtual address space into which the page is mapped.
  325. */
  326. #define PAGE_MAPPING_ANON 1
  327. #define PAGE_MAPPING_KSM 2
  328. #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
  329. static inline int PageAnon(struct page *page)
  330. {
  331. return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
  332. }
  333. #ifdef CONFIG_KSM
  334. /*
  335. * A KSM page is one of those write-protected "shared pages" or "merged pages"
  336. * which KSM maps into multiple mms, wherever identical anonymous page content
  337. * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
  338. * anon_vma, but to that page's node of the stable tree.
  339. */
  340. static inline int PageKsm(struct page *page)
  341. {
  342. return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
  343. (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
  344. }
  345. #else
  346. TESTPAGEFLAG_FALSE(Ksm)
  347. #endif
  348. u64 stable_page_flags(struct page *page);
  349. static inline int PageUptodate(struct page *page)
  350. {
  351. int ret = test_bit(PG_uptodate, &(page)->flags);
  352. /*
  353. * Must ensure that the data we read out of the page is loaded
  354. * _after_ we've loaded page->flags to check for PageUptodate.
  355. * We can skip the barrier if the page is not uptodate, because
  356. * we wouldn't be reading anything from it.
  357. *
  358. * See SetPageUptodate() for the other side of the story.
  359. */
  360. if (ret)
  361. smp_rmb();
  362. return ret;
  363. }
  364. static inline void __SetPageUptodate(struct page *page)
  365. {
  366. smp_wmb();
  367. __set_bit(PG_uptodate, &page->flags);
  368. }
  369. static inline void SetPageUptodate(struct page *page)
  370. {
  371. /*
  372. * Memory barrier must be issued before setting the PG_uptodate bit,
  373. * so that all previous stores issued in order to bring the page
  374. * uptodate are actually visible before PageUptodate becomes true.
  375. */
  376. smp_wmb();
  377. set_bit(PG_uptodate, &page->flags);
  378. }
  379. CLEARPAGEFLAG(Uptodate, uptodate, PF_ANY)
  380. int test_clear_page_writeback(struct page *page);
  381. int __test_set_page_writeback(struct page *page, bool keep_write);
  382. #define test_set_page_writeback(page) \
  383. __test_set_page_writeback(page, false)
  384. #define test_set_page_writeback_keepwrite(page) \
  385. __test_set_page_writeback(page, true)
  386. static inline void set_page_writeback(struct page *page)
  387. {
  388. test_set_page_writeback(page);
  389. }
  390. static inline void set_page_writeback_keepwrite(struct page *page)
  391. {
  392. test_set_page_writeback_keepwrite(page);
  393. }
  394. __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
  395. static inline void set_compound_head(struct page *page, struct page *head)
  396. {
  397. WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
  398. }
  399. static inline void clear_compound_head(struct page *page)
  400. {
  401. WRITE_ONCE(page->compound_head, 0);
  402. }
  403. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  404. static inline void ClearPageCompound(struct page *page)
  405. {
  406. BUG_ON(!PageHead(page));
  407. ClearPageHead(page);
  408. }
  409. #endif
  410. #define PG_head_mask ((1L << PG_head))
  411. #ifdef CONFIG_HUGETLB_PAGE
  412. int PageHuge(struct page *page);
  413. int PageHeadHuge(struct page *page);
  414. bool page_huge_active(struct page *page);
  415. #else
  416. TESTPAGEFLAG_FALSE(Huge)
  417. TESTPAGEFLAG_FALSE(HeadHuge)
  418. static inline bool page_huge_active(struct page *page)
  419. {
  420. return 0;
  421. }
  422. #endif
  423. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  424. /*
  425. * PageHuge() only returns true for hugetlbfs pages, but not for
  426. * normal or transparent huge pages.
  427. *
  428. * PageTransHuge() returns true for both transparent huge and
  429. * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
  430. * called only in the core VM paths where hugetlbfs pages can't exist.
  431. */
  432. static inline int PageTransHuge(struct page *page)
  433. {
  434. VM_BUG_ON_PAGE(PageTail(page), page);
  435. return PageHead(page);
  436. }
  437. /*
  438. * PageTransCompound returns true for both transparent huge pages
  439. * and hugetlbfs pages, so it should only be called when it's known
  440. * that hugetlbfs pages aren't involved.
  441. */
  442. static inline int PageTransCompound(struct page *page)
  443. {
  444. return PageCompound(page);
  445. }
  446. /*
  447. * PageTransTail returns true for both transparent huge pages
  448. * and hugetlbfs pages, so it should only be called when it's known
  449. * that hugetlbfs pages aren't involved.
  450. */
  451. static inline int PageTransTail(struct page *page)
  452. {
  453. return PageTail(page);
  454. }
  455. #else
  456. TESTPAGEFLAG_FALSE(TransHuge)
  457. TESTPAGEFLAG_FALSE(TransCompound)
  458. TESTPAGEFLAG_FALSE(TransTail)
  459. #endif
  460. /*
  461. * PageBuddy() indicate that the page is free and in the buddy system
  462. * (see mm/page_alloc.c).
  463. *
  464. * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to
  465. * -2 so that an underflow of the page_mapcount() won't be mistaken
  466. * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very
  467. * efficiently by most CPU architectures.
  468. */
  469. #define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
  470. static inline int PageBuddy(struct page *page)
  471. {
  472. return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE;
  473. }
  474. static inline void __SetPageBuddy(struct page *page)
  475. {
  476. VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
  477. atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE);
  478. }
  479. static inline void __ClearPageBuddy(struct page *page)
  480. {
  481. VM_BUG_ON_PAGE(!PageBuddy(page), page);
  482. atomic_set(&page->_mapcount, -1);
  483. }
  484. #define PAGE_BALLOON_MAPCOUNT_VALUE (-256)
  485. static inline int PageBalloon(struct page *page)
  486. {
  487. return atomic_read(&page->_mapcount) == PAGE_BALLOON_MAPCOUNT_VALUE;
  488. }
  489. static inline void __SetPageBalloon(struct page *page)
  490. {
  491. VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
  492. atomic_set(&page->_mapcount, PAGE_BALLOON_MAPCOUNT_VALUE);
  493. }
  494. static inline void __ClearPageBalloon(struct page *page)
  495. {
  496. VM_BUG_ON_PAGE(!PageBalloon(page), page);
  497. atomic_set(&page->_mapcount, -1);
  498. }
  499. /*
  500. * If network-based swap is enabled, sl*b must keep track of whether pages
  501. * were allocated from pfmemalloc reserves.
  502. */
  503. static inline int PageSlabPfmemalloc(struct page *page)
  504. {
  505. VM_BUG_ON_PAGE(!PageSlab(page), page);
  506. return PageActive(page);
  507. }
  508. static inline void SetPageSlabPfmemalloc(struct page *page)
  509. {
  510. VM_BUG_ON_PAGE(!PageSlab(page), page);
  511. SetPageActive(page);
  512. }
  513. static inline void __ClearPageSlabPfmemalloc(struct page *page)
  514. {
  515. VM_BUG_ON_PAGE(!PageSlab(page), page);
  516. __ClearPageActive(page);
  517. }
  518. static inline void ClearPageSlabPfmemalloc(struct page *page)
  519. {
  520. VM_BUG_ON_PAGE(!PageSlab(page), page);
  521. ClearPageActive(page);
  522. }
  523. #ifdef CONFIG_MMU
  524. #define __PG_MLOCKED (1 << PG_mlocked)
  525. #else
  526. #define __PG_MLOCKED 0
  527. #endif
  528. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  529. #define __PG_COMPOUND_LOCK (1 << PG_compound_lock)
  530. #else
  531. #define __PG_COMPOUND_LOCK 0
  532. #endif
  533. /*
  534. * Flags checked when a page is freed. Pages being freed should not have
  535. * these flags set. It they are, there is a problem.
  536. */
  537. #define PAGE_FLAGS_CHECK_AT_FREE \
  538. (1 << PG_lru | 1 << PG_locked | \
  539. 1 << PG_private | 1 << PG_private_2 | \
  540. 1 << PG_writeback | 1 << PG_reserved | \
  541. 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
  542. 1 << PG_unevictable | __PG_MLOCKED | \
  543. __PG_COMPOUND_LOCK)
  544. /*
  545. * Flags checked when a page is prepped for return by the page allocator.
  546. * Pages being prepped should not have these flags set. It they are set,
  547. * there has been a kernel bug or struct page corruption.
  548. *
  549. * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
  550. * alloc-free cycle to prevent from reusing the page.
  551. */
  552. #define PAGE_FLAGS_CHECK_AT_PREP \
  553. (((1 << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
  554. #define PAGE_FLAGS_PRIVATE \
  555. (1 << PG_private | 1 << PG_private_2)
  556. /**
  557. * page_has_private - Determine if page has private stuff
  558. * @page: The page to be checked
  559. *
  560. * Determine if a page has private stuff, indicating that release routines
  561. * should be invoked upon it.
  562. */
  563. static inline int page_has_private(struct page *page)
  564. {
  565. return !!(page->flags & PAGE_FLAGS_PRIVATE);
  566. }
  567. #undef PF_ANY
  568. #undef PF_HEAD
  569. #undef PF_NO_TAIL
  570. #undef PF_NO_COMPOUND
  571. #endif /* !__GENERATING_BOUNDS_H */
  572. #endif /* PAGE_FLAGS_H */