include/linux/page-flags.h

   1 /*
   2  * Macros for manipulating and testing page->flags
   3  */
   4
   5 #ifndef PAGE_FLAGS_H
   6 #define PAGE_FLAGS_H
   7
   8 #include <linux/types.h>
   9 #include <linux/bug.h>
  10 #include <linux/mmdebug.h>
  11 #ifndef __GENERATING_BOUNDS_H
  12 #include <linux/mm_types.h>
  13 #include <generated/bounds.h>
  14 #endif /* !__GENERATING_BOUNDS_H */
  15
  16 /*
  17  * Various page->flags bits:
  18  *
  19  * PG_reserved is set for special pages, which can never be swapped out. Some
  20  * of them might not even exist (eg empty_bad_page)...
  21  *
  22  * The PG_private bitflag is set on pagecache pages if they contain filesystem
  23  * specific data (which is normally at page->private). It can be used by
  24  * private allocations for its own usage.
  25  *
  26  * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
  27  * and cleared when writeback _starts_ or when read _completes_. PG_writeback
  28  * is set before writeback starts and cleared when it finishes.
  29  *
  30  * PG_locked also pins a page in pagecache, and blocks truncation of the file
  31  * while it is held.
  32  *
  33  * page_waitqueue(page) is a wait queue of all tasks waiting for the page
  34  * to become unlocked.
  35  *
  36  * PG_uptodate tells whether the page's contents is valid.  When a read
  37  * completes, the page becomes uptodate, unless a disk I/O error happened.
  38  *
  39  * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
  40  * file-backed pagecache (see mm/vmscan.c).
  41  *
  42  * PG_error is set to indicate that an I/O error occurred on this page.
  43  *
  44  * PG_arch_1 is an architecture specific page state bit.  The generic code
  45  * guarantees that this bit is cleared for a page when it first is entered into
  46  * the page cache.
  47  *
  48  * PG_highmem pages are not permanently mapped into the kernel virtual address
  49  * space, they need to be kmapped separately for doing IO on the pages.  The
  50  * struct page (these bits with information) are always mapped into kernel
  51  * address space...
  52  *
  53  * PG_hwpoison indicates that a page got corrupted in hardware and contains
  54  * data with incorrect ECC bits that triggered a machine check. Accessing is
  55  * not safe since it may cause another machine check. Don't touch!
  56  */
  57
  58 /*
  59  * Don't use the *_dontuse flags.  Use the macros.  Otherwise you'll break
  60  * locked- and dirty-page accounting.
  61  *
  62  * The page flags field is split into two parts, the main flags area
  63  * which extends from the low bits upwards, and the fields area which
  64  * extends from the high bits downwards.
  65  *
  66  *  | FIELD | ... | FLAGS |
  67  *  N-1           ^       0
  68  *               (NR_PAGEFLAGS)
  69  *
  70  * The fields area is reserved for fields mapping zone, node (for NUMA) and
  71  * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
  72  * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
  73  */
  74 enum pageflags {
  75         PG_locked,              /* Page is locked. Don't touch. */
  76         PG_error,
  77         PG_referenced,
  78         PG_uptodate,
  79         PG_dirty,
  80         PG_lru,
  81         PG_active,
  82         PG_slab,
  83         PG_owner_priv_1,        /* Owner use. If pagecache, fs may use*/
  84         PG_arch_1,
  85         PG_reserved,
  86         PG_private,             /* If pagecache, has fs-private data */
  87         PG_private_2,           /* If pagecache, has fs aux data */
  88         PG_writeback,           /* Page is under writeback */
  89         PG_head,                /* A head page */
  90         PG_swapcache,           /* Swap page: swp_entry_t in private */
  91         PG_mappedtodisk,        /* Has blocks allocated on-disk */
  92         PG_reclaim,             /* To be reclaimed asap */
  93         PG_swapbacked,          /* Page is backed by RAM/swap */
  94         PG_unevictable,         /* Page is "unevictable"  */
  95 #ifdef CONFIG_MMU
  96         PG_mlocked,             /* Page is vma mlocked */
  97 #endif
  98 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
  99         PG_uncached,            /* Page has been mapped as uncached */
 100 #endif
 101 #ifdef CONFIG_MEMORY_FAILURE
 102         PG_hwpoison,            /* hardware poisoned page. Don't touch */
 103 #endif
 104 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 105         PG_compound_lock,
 106 #endif
 107 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
 108         PG_young,
 109         PG_idle,
 110 #endif
 111         __NR_PAGEFLAGS,
 112
 113         /* Filesystems */
 114         PG_checked = PG_owner_priv_1,
 115
 116         /* Two page bits are conscripted by FS-Cache to maintain local caching
 117          * state.  These bits are set on pages belonging to the netfs's inodes
 118          * when those inodes are being locally cached.
 119          */
 120         PG_fscache = PG_private_2,      /* page backed by cache */
 121
 122         /* XEN */
 123         /* Pinned in Xen as a read-only pagetable page. */
 124         PG_pinned = PG_owner_priv_1,
 125         /* Pinned as part of domain save (see xen_mm_pin_all()). */
 126         PG_savepinned = PG_dirty,
 127         /* Has a grant mapping of another (foreign) domain's page. */
 128         PG_foreign = PG_owner_priv_1,
 129
 130         /* SLOB */
 131         PG_slob_free = PG_private,
 132 };
 133
 134 #ifndef __GENERATING_BOUNDS_H
 135
 136 struct page;    /* forward declaration */
 137
 138 static inline struct page *compound_head(struct page *page)
 139 {
 140         unsigned long head = READ_ONCE(page->compound_head);
 141
 142         if (unlikely(head & 1))
 143                 return (struct page *) (head - 1);
 144         return page;
 145 }
 146
 147 static inline int PageTail(struct page *page)
 148 {
 149         return READ_ONCE(page->compound_head) & 1;
 150 }
 151
 152 static inline int PageCompound(struct page *page)
 153 {
 154         return test_bit(PG_head, &page->flags) || PageTail(page);
 155 }
 156
 157 /*
 158  * Page flags policies wrt compound pages
 159  *
 160  * PF_ANY:
 161  *     the page flag is relevant for small, head and tail pages.
 162  *
 163  * PF_HEAD:
 164  *     for compound page all operations related to the page flag applied to
 165  *     head page.
 166  *
 167  * PF_NO_TAIL:
 168  *     modifications of the page flag must be done on small or head pages,
 169  *     checks can be done on tail pages too.
 170  *
 171  * PF_NO_COMPOUND:
 172  *     the page flag is not relevant for compound pages.
 173  */
 174 #define PF_ANY(page, enforce)   page
 175 #define PF_HEAD(page, enforce)  compound_head(page)
 176 #define PF_NO_TAIL(page, enforce) ({                                    \
 177                 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page);     \
 178                 compound_head(page);})
 179 #define PF_NO_COMPOUND(page, enforce) ({                                        \
 180                 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
 181                 page;})
 182
 183 /*
 184  * Macros to create function definitions for page flags
 185  */
 186 #define TESTPAGEFLAG(uname, lname, policy)                              \
 187 static inline int Page##uname(struct page *page)                        \
 188         { return test_bit(PG_##lname, &policy(page, 0)->flags); }
 189
 190 #define SETPAGEFLAG(uname, lname, policy)                               \
 191 static inline void SetPage##uname(struct page *page)                    \
 192         { set_bit(PG_##lname, &policy(page, 1)->flags); }
 193
 194 #define CLEARPAGEFLAG(uname, lname, policy)                             \
 195 static inline void ClearPage##uname(struct page *page)                  \
 196         { clear_bit(PG_##lname, &policy(page, 1)->flags); }
 197
 198 #define __SETPAGEFLAG(uname, lname, policy)                             \
 199 static inline void __SetPage##uname(struct page *page)                  \
 200         { __set_bit(PG_##lname, &policy(page, 1)->flags); }
 201
 202 #define __CLEARPAGEFLAG(uname, lname, policy)                           \
 203 static inline void __ClearPage##uname(struct page *page)                \
 204         { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
 205
 206 #define TESTSETFLAG(uname, lname, policy)                               \
 207 static inline int TestSetPage##uname(struct page *page)                 \
 208         { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
 209
 210 #define TESTCLEARFLAG(uname, lname, policy)                             \
 211 static inline int TestClearPage##uname(struct page *page)               \
 212         { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
 213
 214 #define __TESTCLEARFLAG(uname, lname, policy)                           \
 215 static inline int __TestClearPage##uname(struct page *page)             \
 216         { return __test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
 217
 218 #define PAGEFLAG(uname, lname, policy)                                  \
 219         TESTPAGEFLAG(uname, lname, policy)                              \
 220         SETPAGEFLAG(uname, lname, policy)                               \
 221         CLEARPAGEFLAG(uname, lname, policy)
 222
 223 #define __PAGEFLAG(uname, lname, policy)                                \
 224         TESTPAGEFLAG(uname, lname, policy)                              \
 225         __SETPAGEFLAG(uname, lname, policy)                             \
 226         __CLEARPAGEFLAG(uname, lname, policy)
 227
 228 #define TESTSCFLAG(uname, lname, policy)                                \
 229         TESTSETFLAG(uname, lname, policy)                               \
 230         TESTCLEARFLAG(uname, lname, policy)
 231
 232 #define TESTPAGEFLAG_FALSE(uname)                                       \
 233 static inline int Page##uname(const struct page *page) { return 0; }
 234
 235 #define SETPAGEFLAG_NOOP(uname)                                         \
 236 static inline void SetPage##uname(struct page *page) {  }
 237
 238 #define CLEARPAGEFLAG_NOOP(uname)                                       \
 239 static inline void ClearPage##uname(struct page *page) {  }
 240
 241 #define __CLEARPAGEFLAG_NOOP(uname)                                     \
 242 static inline void __ClearPage##uname(struct page *page) {  }
 243
 244 #define TESTSETFLAG_FALSE(uname)                                        \
 245 static inline int TestSetPage##uname(struct page *page) { return 0; }
 246
 247 #define TESTCLEARFLAG_FALSE(uname)                                      \
 248 static inline int TestClearPage##uname(struct page *page) { return 0; }
 249
 250 #define __TESTCLEARFLAG_FALSE(uname)                                    \
 251 static inline int __TestClearPage##uname(struct page *page) { return 0; }
 252
 253 #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname)                 \
 254         SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
 255
 256 #define TESTSCFLAG_FALSE(uname)                                         \
 257         TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
 258
 259 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
 260 PAGEFLAG(Error, error, PF_ANY) TESTCLEARFLAG(Error, error, PF_ANY)
 261 PAGEFLAG(Referenced, referenced, PF_ANY) TESTCLEARFLAG(Referenced, referenced, PF_ANY)
 262         __SETPAGEFLAG(Referenced, referenced, PF_ANY)
 263 PAGEFLAG(Dirty, dirty, PF_ANY) TESTSCFLAG(Dirty, dirty, PF_ANY)
 264         __CLEARPAGEFLAG(Dirty, dirty, PF_ANY)
 265 PAGEFLAG(LRU, lru, PF_ANY) __CLEARPAGEFLAG(LRU, lru, PF_ANY)
 266 PAGEFLAG(Active, active, PF_ANY) __CLEARPAGEFLAG(Active, active, PF_ANY)
 267         TESTCLEARFLAG(Active, active, PF_ANY)
 268 __PAGEFLAG(Slab, slab, PF_ANY)
 269 PAGEFLAG(Checked, checked, PF_ANY)              /* Used by some filesystems */
 270 PAGEFLAG(Pinned, pinned, PF_ANY) TESTSCFLAG(Pinned, pinned, PF_ANY)     /* Xen */
 271 PAGEFLAG(SavePinned, savepinned, PF_ANY);                       /* Xen */
 272 PAGEFLAG(Foreign, foreign, PF_ANY);                             /* Xen */
 273 PAGEFLAG(Reserved, reserved, PF_ANY) __CLEARPAGEFLAG(Reserved, reserved, PF_ANY)
 274 PAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 275         __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 276         __SETPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 277
 278 __PAGEFLAG(SlobFree, slob_free, PF_ANY)
 279
 280 /*
 281  * Private page markings that may be used by the filesystem that owns the page
 282  * for its own purposes.
 283  * - PG_private and PG_private_2 cause releasepage() and co to be invoked
 284  */
 285 PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
 286         __CLEARPAGEFLAG(Private, private, PF_ANY)
 287 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
 288 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
 289         TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
 290
 291 /*
 292  * Only test-and-set exist for PG_writeback.  The unconditional operators are
 293  * risky: they bypass page accounting.
 294  */
 295 TESTPAGEFLAG(Writeback, writeback, PF_ANY) TESTSCFLAG(Writeback, writeback, PF_ANY)
 296 PAGEFLAG(MappedToDisk, mappedtodisk, PF_ANY)
 297
 298 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
 299 PAGEFLAG(Reclaim, reclaim, PF_ANY) TESTCLEARFLAG(Reclaim, reclaim, PF_ANY)
 300 PAGEFLAG(Readahead, reclaim, PF_ANY) TESTCLEARFLAG(Readahead, reclaim, PF_ANY)
 301
 302 #ifdef CONFIG_HIGHMEM
 303 /*
 304  * Must use a macro here due to header dependency issues. page_zone() is not
 305  * available at this point.
 306  */
 307 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
 308 #else
 309 PAGEFLAG_FALSE(HighMem)
 310 #endif
 311
 312 #ifdef CONFIG_SWAP
 313 PAGEFLAG(SwapCache, swapcache, PF_ANY)
 314 #else
 315 PAGEFLAG_FALSE(SwapCache)
 316 #endif
 317
 318 PAGEFLAG(Unevictable, unevictable, PF_ANY)
 319         __CLEARPAGEFLAG(Unevictable, unevictable, PF_ANY)
 320         TESTCLEARFLAG(Unevictable, unevictable, PF_ANY)
 321
 322 #ifdef CONFIG_MMU
 323 PAGEFLAG(Mlocked, mlocked, PF_ANY) __CLEARPAGEFLAG(Mlocked, mlocked, PF_ANY)
 324         TESTSCFLAG(Mlocked, mlocked, PF_ANY) __TESTCLEARFLAG(Mlocked, mlocked, PF_ANY)
 325 #else
 326 PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
 327         TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
 328 #endif
 329
 330 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
 331 PAGEFLAG(Uncached, uncached, PF_ANY)
 332 #else
 333 PAGEFLAG_FALSE(Uncached)
 334 #endif
 335
 336 #ifdef CONFIG_MEMORY_FAILURE
 337 PAGEFLAG(HWPoison, hwpoison, PF_ANY)
 338 TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
 339 #define __PG_HWPOISON (1UL << PG_hwpoison)
 340 #else
 341 PAGEFLAG_FALSE(HWPoison)
 342 #define __PG_HWPOISON 0
 343 #endif
 344
 345 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
 346 TESTPAGEFLAG(Young, young, PF_ANY)
 347 SETPAGEFLAG(Young, young, PF_ANY)
 348 TESTCLEARFLAG(Young, young, PF_ANY)
 349 PAGEFLAG(Idle, idle, PF_ANY)
 350 #endif
 351
 352 /*
 353  * On an anonymous page mapped into a user virtual memory area,
 354  * page->mapping points to its anon_vma, not to a struct address_space;
 355  * with the PAGE_MAPPING_ANON bit set to distinguish it.  See rmap.h.
 356  *
 357  * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
 358  * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit;
 359  * and then page->mapping points, not to an anon_vma, but to a private
 360  * structure which KSM associates with that merged page.  See ksm.h.
 361  *
 362  * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used.
 363  *
 364  * Please note that, confusingly, "page_mapping" refers to the inode
 365  * address_space which maps the page from disk; whereas "page_mapped"
 366  * refers to user virtual address space into which the page is mapped.
 367  */
 368 #define PAGE_MAPPING_ANON       1
 369 #define PAGE_MAPPING_KSM        2
 370 #define PAGE_MAPPING_FLAGS      (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
 371
 372 static inline int PageAnon(struct page *page)
 373 {
 374         return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
 375 }
 376
 377 #ifdef CONFIG_KSM
 378 /*
 379  * A KSM page is one of those write-protected "shared pages" or "merged pages"
 380  * which KSM maps into multiple mms, wherever identical anonymous page content
 381  * is found in VM_MERGEABLE vmas.  It's a PageAnon page, pointing not to any
 382  * anon_vma, but to that page's node of the stable tree.
 383  */
 384 static inline int PageKsm(struct page *page)
 385 {
 386         return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
 387                                 (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
 388 }
 389 #else
 390 TESTPAGEFLAG_FALSE(Ksm)
 391 #endif
 392
 393 u64 stable_page_flags(struct page *page);
 394
 395 static inline int PageUptodate(struct page *page)
 396 {
 397         int ret = test_bit(PG_uptodate, &(page)->flags);
 398
 399         /*
 400          * Must ensure that the data we read out of the page is loaded
 401          * _after_ we've loaded page->flags to check for PageUptodate.
 402          * We can skip the barrier if the page is not uptodate, because
 403          * we wouldn't be reading anything from it.
 404          *
 405          * See SetPageUptodate() for the other side of the story.
 406          */
 407         if (ret)
 408                 smp_rmb();
 409
 410         return ret;
 411 }
 412
 413 static inline void __SetPageUptodate(struct page *page)
 414 {
 415         smp_wmb();
 416         __set_bit(PG_uptodate, &(page)->flags);
 417 }
 418
 419 static inline void SetPageUptodate(struct page *page)
 420 {
 421         /*
 422          * Memory barrier must be issued before setting the PG_uptodate bit,
 423          * so that all previous stores issued in order to bring the page
 424          * uptodate are actually visible before PageUptodate becomes true.
 425          */
 426         smp_wmb();
 427         set_bit(PG_uptodate, &(page)->flags);
 428 }
 429
 430 CLEARPAGEFLAG(Uptodate, uptodate, PF_ANY)
 431
 432 int test_clear_page_writeback(struct page *page);
 433 int __test_set_page_writeback(struct page *page, bool keep_write);
 434
 435 #define test_set_page_writeback(page)                   \
 436         __test_set_page_writeback(page, false)
 437 #define test_set_page_writeback_keepwrite(page) \
 438         __test_set_page_writeback(page, true)
 439
 440 static inline void set_page_writeback(struct page *page)
 441 {
 442         test_set_page_writeback(page);
 443 }
 444
 445 static inline void set_page_writeback_keepwrite(struct page *page)
 446 {
 447         test_set_page_writeback_keepwrite(page);
 448 }
 449
 450 __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
 451
 452 static inline void set_compound_head(struct page *page, struct page *head)
 453 {
 454         WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
 455 }
 456
 457 static inline void clear_compound_head(struct page *page)
 458 {
 459         WRITE_ONCE(page->compound_head, 0);
 460 }
 461
 462 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 463 static inline void ClearPageCompound(struct page *page)
 464 {
 465         BUG_ON(!PageHead(page));
 466         ClearPageHead(page);
 467 }
 468 #endif
 469
 470 #define PG_head_mask ((1L << PG_head))
 471
 472 #ifdef CONFIG_HUGETLB_PAGE
 473 int PageHuge(struct page *page);
 474 int PageHeadHuge(struct page *page);
 475 bool page_huge_active(struct page *page);
 476 #else
 477 TESTPAGEFLAG_FALSE(Huge)
 478 TESTPAGEFLAG_FALSE(HeadHuge)
 479
 480 static inline bool page_huge_active(struct page *page)
 481 {
 482         return 0;
 483 }
 484 #endif
 485
 486
 487 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 488 /*
 489  * PageHuge() only returns true for hugetlbfs pages, but not for
 490  * normal or transparent huge pages.
 491  *
 492  * PageTransHuge() returns true for both transparent huge and
 493  * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
 494  * called only in the core VM paths where hugetlbfs pages can't exist.
 495  */
 496 static inline int PageTransHuge(struct page *page)
 497 {
 498         VM_BUG_ON_PAGE(PageTail(page), page);
 499         return PageHead(page);
 500 }
 501
 502 /*
 503  * PageTransCompound returns true for both transparent huge pages
 504  * and hugetlbfs pages, so it should only be called when it's known
 505  * that hugetlbfs pages aren't involved.
 506  */
 507 static inline int PageTransCompound(struct page *page)
 508 {
 509         return PageCompound(page);
 510 }
 511
 512 /*
 513  * PageTransTail returns true for both transparent huge pages
 514  * and hugetlbfs pages, so it should only be called when it's known
 515  * that hugetlbfs pages aren't involved.
 516  */
 517 static inline int PageTransTail(struct page *page)
 518 {
 519         return PageTail(page);
 520 }
 521
 522 #else
 523 TESTPAGEFLAG_FALSE(TransHuge)
 524 TESTPAGEFLAG_FALSE(TransCompound)
 525 TESTPAGEFLAG_FALSE(TransTail)
 526 #endif
 527
 528 /*
 529  * PageBuddy() indicate that the page is free and in the buddy system
 530  * (see mm/page_alloc.c).
 531  *
 532  * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to
 533  * -2 so that an underflow of the page_mapcount() won't be mistaken
 534  * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very
 535  * efficiently by most CPU architectures.
 536  */
 537 #define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
 538
 539 static inline int PageBuddy(struct page *page)
 540 {
 541         return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE;
 542 }
 543
 544 static inline void __SetPageBuddy(struct page *page)
 545 {
 546         VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
 547         atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE);
 548 }
 549
 550 static inline void __ClearPageBuddy(struct page *page)
 551 {
 552         VM_BUG_ON_PAGE(!PageBuddy(page), page);
 553         atomic_set(&page->_mapcount, -1);
 554 }
 555
 556 #define PAGE_BALLOON_MAPCOUNT_VALUE (-256)
 557
 558 static inline int PageBalloon(struct page *page)
 559 {
 560         return atomic_read(&page->_mapcount) == PAGE_BALLOON_MAPCOUNT_VALUE;
 561 }
 562
 563 static inline void __SetPageBalloon(struct page *page)
 564 {
 565         VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
 566         atomic_set(&page->_mapcount, PAGE_BALLOON_MAPCOUNT_VALUE);
 567 }
 568
 569 static inline void __ClearPageBalloon(struct page *page)
 570 {
 571         VM_BUG_ON_PAGE(!PageBalloon(page), page);
 572         atomic_set(&page->_mapcount, -1);
 573 }
 574
 575 /*
 576  * If network-based swap is enabled, sl*b must keep track of whether pages
 577  * were allocated from pfmemalloc reserves.
 578  */
 579 static inline int PageSlabPfmemalloc(struct page *page)
 580 {
 581         VM_BUG_ON_PAGE(!PageSlab(page), page);
 582         return PageActive(page);
 583 }
 584
 585 static inline void SetPageSlabPfmemalloc(struct page *page)
 586 {
 587         VM_BUG_ON_PAGE(!PageSlab(page), page);
 588         SetPageActive(page);
 589 }
 590
 591 static inline void __ClearPageSlabPfmemalloc(struct page *page)
 592 {
 593         VM_BUG_ON_PAGE(!PageSlab(page), page);
 594         __ClearPageActive(page);
 595 }
 596
 597 static inline void ClearPageSlabPfmemalloc(struct page *page)
 598 {
 599         VM_BUG_ON_PAGE(!PageSlab(page), page);
 600         ClearPageActive(page);
 601 }
 602
 603 #ifdef CONFIG_MMU
 604 #define __PG_MLOCKED            (1 << PG_mlocked)
 605 #else
 606 #define __PG_MLOCKED            0
 607 #endif
 608
 609 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 610 #define __PG_COMPOUND_LOCK              (1 << PG_compound_lock)
 611 #else
 612 #define __PG_COMPOUND_LOCK              0
 613 #endif
 614
 615 /*
 616  * Flags checked when a page is freed.  Pages being freed should not have
 617  * these flags set.  It they are, there is a problem.
 618  */
 619 #define PAGE_FLAGS_CHECK_AT_FREE \
 620         (1 << PG_lru     | 1 << PG_locked    | \
 621          1 << PG_private | 1 << PG_private_2 | \
 622          1 << PG_writeback | 1 << PG_reserved | \
 623          1 << PG_slab    | 1 << PG_swapcache | 1 << PG_active | \
 624          1 << PG_unevictable | __PG_MLOCKED | \
 625          __PG_COMPOUND_LOCK)
 626
 627 /*
 628  * Flags checked when a page is prepped for return by the page allocator.
 629  * Pages being prepped should not have these flags set.  It they are set,
 630  * there has been a kernel bug or struct page corruption.
 631  *
 632  * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
 633  * alloc-free cycle to prevent from reusing the page.
 634  */
 635 #define PAGE_FLAGS_CHECK_AT_PREP        \
 636         (((1 << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
 637
 638 #define PAGE_FLAGS_PRIVATE                              \
 639         (1 << PG_private | 1 << PG_private_2)
 640 /**
 641  * page_has_private - Determine if page has private stuff
 642  * @page: The page to be checked
 643  *
 644  * Determine if a page has private stuff, indicating that release routines
 645  * should be invoked upon it.
 646  */
 647 static inline int page_has_private(struct page *page)
 648 {
 649         return !!(page->flags & PAGE_FLAGS_PRIVATE);
 650 }
 651
 652 #undef PF_ANY
 653 #undef PF_HEAD
 654 #undef PF_NO_TAIL
 655 #undef PF_NO_COMPOUND
 656 #endif /* !__GENERATING_BOUNDS_H */
 657
 658 #endif  /* PAGE_FLAGS_H */