2 * Macros for manipulating and testing page->flags
8 #include <linux/types.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 */
17 * Various page->flags bits:
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)...
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.
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.
30 * PG_locked also pins a page in pagecache, and blocks truncation of the file
33 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
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.
39 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
40 * file-backed pagecache (see mm/vmscan.c).
42 * PG_error is set to indicate that an I/O error occurred on this page.
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
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
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!
59 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
60 * locked- and dirty-page accounting.
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.
66 * | FIELD | ... | FLAGS |
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).
75 PG_locked
, /* Page is locked. Don't touch. */
83 PG_owner_priv_1
, /* Owner use. If pagecache, fs may use*/
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" */
96 PG_mlocked
, /* Page is vma mlocked */
98 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
99 PG_uncached
, /* Page has been mapped as uncached */
101 #ifdef CONFIG_MEMORY_FAILURE
102 PG_hwpoison
, /* hardware poisoned page. Don't touch */
104 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
111 PG_checked
= PG_owner_priv_1
,
113 /* Two page bits are conscripted by FS-Cache to maintain local caching
114 * state. These bits are set on pages belonging to the netfs's inodes
115 * when those inodes are being locally cached.
117 PG_fscache
= PG_private_2
, /* page backed by cache */
120 /* Pinned in Xen as a read-only pagetable page. */
121 PG_pinned
= PG_owner_priv_1
,
122 /* Pinned as part of domain save (see xen_mm_pin_all()). */
123 PG_savepinned
= PG_dirty
,
124 /* Has a grant mapping of another (foreign) domain's page. */
125 PG_foreign
= PG_owner_priv_1
,
128 PG_slob_free
= PG_private
,
130 /* Compound pages. Stored in first tail page's flags */
131 PG_double_map
= PG_private_2
,
133 /* non-lru isolated movable page */
134 PG_isolated
= PG_reclaim
,
137 #ifndef __GENERATING_BOUNDS_H
139 struct page
; /* forward declaration */
141 static inline struct page
*compound_head(struct page
*page
)
143 unsigned long head
= READ_ONCE(page
->compound_head
);
145 if (unlikely(head
& 1))
146 return (struct page
*) (head
- 1);
150 static __always_inline
int PageTail(struct page
*page
)
152 return READ_ONCE(page
->compound_head
) & 1;
155 static __always_inline
int PageCompound(struct page
*page
)
157 return test_bit(PG_head
, &page
->flags
) || PageTail(page
);
161 * Page flags policies wrt compound pages
164 * the page flag is relevant for small, head and tail pages.
167 * for compound page all operations related to the page flag applied to
171 * modifications of the page flag must be done on small or head pages,
172 * checks can be done on tail pages too.
175 * the page flag is not relevant for compound pages.
177 #define PF_ANY(page, enforce) page
178 #define PF_HEAD(page, enforce) compound_head(page)
179 #define PF_NO_TAIL(page, enforce) ({ \
180 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
181 compound_head(page);})
182 #define PF_NO_COMPOUND(page, enforce) ({ \
183 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
187 * Macros to create function definitions for page flags
189 #define TESTPAGEFLAG(uname, lname, policy) \
190 static __always_inline int Page##uname(struct page *page) \
191 { return test_bit(PG_##lname, &policy(page, 0)->flags); }
193 #define SETPAGEFLAG(uname, lname, policy) \
194 static __always_inline void SetPage##uname(struct page *page) \
195 { set_bit(PG_##lname, &policy(page, 1)->flags); }
197 #define CLEARPAGEFLAG(uname, lname, policy) \
198 static __always_inline void ClearPage##uname(struct page *page) \
199 { clear_bit(PG_##lname, &policy(page, 1)->flags); }
201 #define __SETPAGEFLAG(uname, lname, policy) \
202 static __always_inline void __SetPage##uname(struct page *page) \
203 { __set_bit(PG_##lname, &policy(page, 1)->flags); }
205 #define __CLEARPAGEFLAG(uname, lname, policy) \
206 static __always_inline void __ClearPage##uname(struct page *page) \
207 { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
209 #define TESTSETFLAG(uname, lname, policy) \
210 static __always_inline int TestSetPage##uname(struct page *page) \
211 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
213 #define TESTCLEARFLAG(uname, lname, policy) \
214 static __always_inline int TestClearPage##uname(struct page *page) \
215 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
217 #define PAGEFLAG(uname, lname, policy) \
218 TESTPAGEFLAG(uname, lname, policy) \
219 SETPAGEFLAG(uname, lname, policy) \
220 CLEARPAGEFLAG(uname, lname, policy)
222 #define __PAGEFLAG(uname, lname, policy) \
223 TESTPAGEFLAG(uname, lname, policy) \
224 __SETPAGEFLAG(uname, lname, policy) \
225 __CLEARPAGEFLAG(uname, lname, policy)
227 #define TESTSCFLAG(uname, lname, policy) \
228 TESTSETFLAG(uname, lname, policy) \
229 TESTCLEARFLAG(uname, lname, policy)
231 #define TESTPAGEFLAG_FALSE(uname) \
232 static inline int Page##uname(const struct page *page) { return 0; }
234 #define SETPAGEFLAG_NOOP(uname) \
235 static inline void SetPage##uname(struct page *page) { }
237 #define CLEARPAGEFLAG_NOOP(uname) \
238 static inline void ClearPage##uname(struct page *page) { }
240 #define __CLEARPAGEFLAG_NOOP(uname) \
241 static inline void __ClearPage##uname(struct page *page) { }
243 #define TESTSETFLAG_FALSE(uname) \
244 static inline int TestSetPage##uname(struct page *page) { return 0; }
246 #define TESTCLEARFLAG_FALSE(uname) \
247 static inline int TestClearPage##uname(struct page *page) { return 0; }
249 #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
250 SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
252 #define TESTSCFLAG_FALSE(uname) \
253 TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
255 __PAGEFLAG(Locked
, locked
, PF_NO_TAIL
)
256 PAGEFLAG(Error
, error
, PF_NO_COMPOUND
) TESTCLEARFLAG(Error
, error
, PF_NO_COMPOUND
)
257 PAGEFLAG(Referenced
, referenced
, PF_HEAD
)
258 TESTCLEARFLAG(Referenced
, referenced
, PF_HEAD
)
259 __SETPAGEFLAG(Referenced
, referenced
, PF_HEAD
)
260 PAGEFLAG(Dirty
, dirty
, PF_HEAD
) TESTSCFLAG(Dirty
, dirty
, PF_HEAD
)
261 __CLEARPAGEFLAG(Dirty
, dirty
, PF_HEAD
)
262 PAGEFLAG(LRU
, lru
, PF_HEAD
) __CLEARPAGEFLAG(LRU
, lru
, PF_HEAD
)
263 PAGEFLAG(Active
, active
, PF_HEAD
) __CLEARPAGEFLAG(Active
, active
, PF_HEAD
)
264 TESTCLEARFLAG(Active
, active
, PF_HEAD
)
265 __PAGEFLAG(Slab
, slab
, PF_NO_TAIL
)
266 __PAGEFLAG(SlobFree
, slob_free
, PF_NO_TAIL
)
267 PAGEFLAG(Checked
, checked
, PF_NO_COMPOUND
) /* Used by some filesystems */
270 PAGEFLAG(Pinned
, pinned
, PF_NO_COMPOUND
)
271 TESTSCFLAG(Pinned
, pinned
, PF_NO_COMPOUND
)
272 PAGEFLAG(SavePinned
, savepinned
, PF_NO_COMPOUND
);
273 PAGEFLAG(Foreign
, foreign
, PF_NO_COMPOUND
);
275 PAGEFLAG(Reserved
, reserved
, PF_NO_COMPOUND
)
276 __CLEARPAGEFLAG(Reserved
, reserved
, PF_NO_COMPOUND
)
277 PAGEFLAG(SwapBacked
, swapbacked
, PF_NO_TAIL
)
278 __CLEARPAGEFLAG(SwapBacked
, swapbacked
, PF_NO_TAIL
)
279 __SETPAGEFLAG(SwapBacked
, swapbacked
, PF_NO_TAIL
)
282 * Private page markings that may be used by the filesystem that owns the page
283 * for its own purposes.
284 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
286 PAGEFLAG(Private
, private, PF_ANY
) __SETPAGEFLAG(Private
, private, PF_ANY
)
287 __CLEARPAGEFLAG(Private
, private, PF_ANY
)
288 PAGEFLAG(Private2
, private_2
, PF_ANY
) TESTSCFLAG(Private2
, private_2
, PF_ANY
)
289 PAGEFLAG(OwnerPriv1
, owner_priv_1
, PF_ANY
)
290 TESTCLEARFLAG(OwnerPriv1
, owner_priv_1
, PF_ANY
)
293 * Only test-and-set exist for PG_writeback. The unconditional operators are
294 * risky: they bypass page accounting.
296 TESTPAGEFLAG(Writeback
, writeback
, PF_NO_COMPOUND
)
297 TESTSCFLAG(Writeback
, writeback
, PF_NO_COMPOUND
)
298 PAGEFLAG(MappedToDisk
, mappedtodisk
, PF_NO_TAIL
)
300 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
301 PAGEFLAG(Reclaim
, reclaim
, PF_NO_TAIL
)
302 TESTCLEARFLAG(Reclaim
, reclaim
, PF_NO_TAIL
)
303 PAGEFLAG(Readahead
, reclaim
, PF_NO_COMPOUND
)
304 TESTCLEARFLAG(Readahead
, reclaim
, PF_NO_COMPOUND
)
306 #ifdef CONFIG_HIGHMEM
308 * Must use a macro here due to header dependency issues. page_zone() is not
309 * available at this point.
311 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
313 PAGEFLAG_FALSE(HighMem
)
317 PAGEFLAG(SwapCache
, swapcache
, PF_NO_COMPOUND
)
319 PAGEFLAG_FALSE(SwapCache
)
322 PAGEFLAG(Unevictable
, unevictable
, PF_HEAD
)
323 __CLEARPAGEFLAG(Unevictable
, unevictable
, PF_HEAD
)
324 TESTCLEARFLAG(Unevictable
, unevictable
, PF_HEAD
)
327 PAGEFLAG(Mlocked
, mlocked
, PF_NO_TAIL
)
328 __CLEARPAGEFLAG(Mlocked
, mlocked
, PF_NO_TAIL
)
329 TESTSCFLAG(Mlocked
, mlocked
, PF_NO_TAIL
)
331 PAGEFLAG_FALSE(Mlocked
) __CLEARPAGEFLAG_NOOP(Mlocked
)
332 TESTSCFLAG_FALSE(Mlocked
)
335 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
336 PAGEFLAG(Uncached
, uncached
, PF_NO_COMPOUND
)
338 PAGEFLAG_FALSE(Uncached
)
341 #ifdef CONFIG_MEMORY_FAILURE
342 PAGEFLAG(HWPoison
, hwpoison
, PF_ANY
)
343 TESTSCFLAG(HWPoison
, hwpoison
, PF_ANY
)
344 #define __PG_HWPOISON (1UL << PG_hwpoison)
346 PAGEFLAG_FALSE(HWPoison
)
347 #define __PG_HWPOISON 0
350 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
351 TESTPAGEFLAG(Young
, young
, PF_ANY
)
352 SETPAGEFLAG(Young
, young
, PF_ANY
)
353 TESTCLEARFLAG(Young
, young
, PF_ANY
)
354 PAGEFLAG(Idle
, idle
, PF_ANY
)
358 * On an anonymous page mapped into a user virtual memory area,
359 * page->mapping points to its anon_vma, not to a struct address_space;
360 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
362 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
363 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
364 * bit; and then page->mapping points, not to an anon_vma, but to a private
365 * structure which KSM associates with that merged page. See ksm.h.
367 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
368 * page and then page->mapping points a struct address_space.
370 * Please note that, confusingly, "page_mapping" refers to the inode
371 * address_space which maps the page from disk; whereas "page_mapped"
372 * refers to user virtual address space into which the page is mapped.
374 #define PAGE_MAPPING_ANON 0x1
375 #define PAGE_MAPPING_MOVABLE 0x2
376 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
377 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
379 static __always_inline
int PageMappingFlags(struct page
*page
)
381 return ((unsigned long)page
->mapping
& PAGE_MAPPING_FLAGS
) != 0;
384 static __always_inline
int PageAnon(struct page
*page
)
386 page
= compound_head(page
);
387 return ((unsigned long)page
->mapping
& PAGE_MAPPING_ANON
) != 0;
390 static __always_inline
int __PageMovable(struct page
*page
)
392 return ((unsigned long)page
->mapping
& PAGE_MAPPING_FLAGS
) ==
393 PAGE_MAPPING_MOVABLE
;
398 * A KSM page is one of those write-protected "shared pages" or "merged pages"
399 * which KSM maps into multiple mms, wherever identical anonymous page content
400 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
401 * anon_vma, but to that page's node of the stable tree.
403 static __always_inline
int PageKsm(struct page
*page
)
405 page
= compound_head(page
);
406 return ((unsigned long)page
->mapping
& PAGE_MAPPING_FLAGS
) ==
410 TESTPAGEFLAG_FALSE(Ksm
)
413 u64
stable_page_flags(struct page
*page
);
415 static inline int PageUptodate(struct page
*page
)
418 page
= compound_head(page
);
419 ret
= test_bit(PG_uptodate
, &(page
)->flags
);
421 * Must ensure that the data we read out of the page is loaded
422 * _after_ we've loaded page->flags to check for PageUptodate.
423 * We can skip the barrier if the page is not uptodate, because
424 * we wouldn't be reading anything from it.
426 * See SetPageUptodate() for the other side of the story.
434 static __always_inline
void __SetPageUptodate(struct page
*page
)
436 VM_BUG_ON_PAGE(PageTail(page
), page
);
438 __set_bit(PG_uptodate
, &page
->flags
);
441 static __always_inline
void SetPageUptodate(struct page
*page
)
443 VM_BUG_ON_PAGE(PageTail(page
), page
);
445 * Memory barrier must be issued before setting the PG_uptodate bit,
446 * so that all previous stores issued in order to bring the page
447 * uptodate are actually visible before PageUptodate becomes true.
450 set_bit(PG_uptodate
, &page
->flags
);
453 CLEARPAGEFLAG(Uptodate
, uptodate
, PF_NO_TAIL
)
455 int test_clear_page_writeback(struct page
*page
);
456 int __test_set_page_writeback(struct page
*page
, bool keep_write
);
458 #define test_set_page_writeback(page) \
459 __test_set_page_writeback(page, false)
460 #define test_set_page_writeback_keepwrite(page) \
461 __test_set_page_writeback(page, true)
463 static inline void set_page_writeback(struct page
*page
)
465 test_set_page_writeback(page
);
468 static inline void set_page_writeback_keepwrite(struct page
*page
)
470 test_set_page_writeback_keepwrite(page
);
473 __PAGEFLAG(Head
, head
, PF_ANY
) CLEARPAGEFLAG(Head
, head
, PF_ANY
)
475 static __always_inline
void set_compound_head(struct page
*page
, struct page
*head
)
477 WRITE_ONCE(page
->compound_head
, (unsigned long)head
+ 1);
480 static __always_inline
void clear_compound_head(struct page
*page
)
482 WRITE_ONCE(page
->compound_head
, 0);
485 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
486 static inline void ClearPageCompound(struct page
*page
)
488 BUG_ON(!PageHead(page
));
493 #define PG_head_mask ((1UL << PG_head))
495 #ifdef CONFIG_HUGETLB_PAGE
496 int PageHuge(struct page
*page
);
497 int PageHeadHuge(struct page
*page
);
498 bool page_huge_active(struct page
*page
);
500 TESTPAGEFLAG_FALSE(Huge
)
501 TESTPAGEFLAG_FALSE(HeadHuge
)
503 static inline bool page_huge_active(struct page
*page
)
510 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
512 * PageHuge() only returns true for hugetlbfs pages, but not for
513 * normal or transparent huge pages.
515 * PageTransHuge() returns true for both transparent huge and
516 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
517 * called only in the core VM paths where hugetlbfs pages can't exist.
519 static inline int PageTransHuge(struct page
*page
)
521 VM_BUG_ON_PAGE(PageTail(page
), page
);
522 return PageHead(page
);
526 * PageTransCompound returns true for both transparent huge pages
527 * and hugetlbfs pages, so it should only be called when it's known
528 * that hugetlbfs pages aren't involved.
530 static inline int PageTransCompound(struct page
*page
)
532 return PageCompound(page
);
536 * PageTransCompoundMap is the same as PageTransCompound, but it also
537 * guarantees the primary MMU has the entire compound page mapped
538 * through pmd_trans_huge, which in turn guarantees the secondary MMUs
539 * can also map the entire compound page. This allows the secondary
540 * MMUs to call get_user_pages() only once for each compound page and
541 * to immediately map the entire compound page with a single secondary
542 * MMU fault. If there will be a pmd split later, the secondary MMUs
543 * will get an update through the MMU notifier invalidation through
546 * Unlike PageTransCompound, this is safe to be called only while
547 * split_huge_pmd() cannot run from under us, like if protected by the
548 * MMU notifier, otherwise it may result in page->_mapcount < 0 false
551 static inline int PageTransCompoundMap(struct page
*page
)
553 return PageTransCompound(page
) && atomic_read(&page
->_mapcount
) < 0;
557 * PageTransTail returns true for both transparent huge pages
558 * and hugetlbfs pages, so it should only be called when it's known
559 * that hugetlbfs pages aren't involved.
561 static inline int PageTransTail(struct page
*page
)
563 return PageTail(page
);
567 * PageDoubleMap indicates that the compound page is mapped with PTEs as well
570 * This is required for optimization of rmap operations for THP: we can postpone
571 * per small page mapcount accounting (and its overhead from atomic operations)
572 * until the first PMD split.
574 * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
575 * by one. This reference will go away with last compound_mapcount.
577 * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
579 static inline int PageDoubleMap(struct page
*page
)
581 return PageHead(page
) && test_bit(PG_double_map
, &page
[1].flags
);
584 static inline void SetPageDoubleMap(struct page
*page
)
586 VM_BUG_ON_PAGE(!PageHead(page
), page
);
587 set_bit(PG_double_map
, &page
[1].flags
);
590 static inline void ClearPageDoubleMap(struct page
*page
)
592 VM_BUG_ON_PAGE(!PageHead(page
), page
);
593 clear_bit(PG_double_map
, &page
[1].flags
);
595 static inline int TestSetPageDoubleMap(struct page
*page
)
597 VM_BUG_ON_PAGE(!PageHead(page
), page
);
598 return test_and_set_bit(PG_double_map
, &page
[1].flags
);
601 static inline int TestClearPageDoubleMap(struct page
*page
)
603 VM_BUG_ON_PAGE(!PageHead(page
), page
);
604 return test_and_clear_bit(PG_double_map
, &page
[1].flags
);
608 TESTPAGEFLAG_FALSE(TransHuge
)
609 TESTPAGEFLAG_FALSE(TransCompound
)
610 TESTPAGEFLAG_FALSE(TransCompoundMap
)
611 TESTPAGEFLAG_FALSE(TransTail
)
612 PAGEFLAG_FALSE(DoubleMap
)
613 TESTSETFLAG_FALSE(DoubleMap
)
614 TESTCLEARFLAG_FALSE(DoubleMap
)
618 * For pages that are never mapped to userspace, page->mapcount may be
619 * used for storing extra information about page type. Any value used
620 * for this purpose must be <= -2, but it's better start not too close
621 * to -2 so that an underflow of the page_mapcount() won't be mistaken
622 * for a special page.
624 #define PAGE_MAPCOUNT_OPS(uname, lname) \
625 static __always_inline int Page##uname(struct page *page) \
627 return atomic_read(&page->_mapcount) == \
628 PAGE_##lname##_MAPCOUNT_VALUE; \
630 static __always_inline void __SetPage##uname(struct page *page) \
632 VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); \
633 atomic_set(&page->_mapcount, PAGE_##lname##_MAPCOUNT_VALUE); \
635 static __always_inline void __ClearPage##uname(struct page *page) \
637 VM_BUG_ON_PAGE(!Page##uname(page), page); \
638 atomic_set(&page->_mapcount, -1); \
642 * PageBuddy() indicate that the page is free and in the buddy system
643 * (see mm/page_alloc.c).
645 #define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
646 PAGE_MAPCOUNT_OPS(Buddy
, BUDDY
)
649 * PageBalloon() is set on pages that are on the balloon page list
650 * (see mm/balloon_compaction.c).
652 #define PAGE_BALLOON_MAPCOUNT_VALUE (-256)
653 PAGE_MAPCOUNT_OPS(Balloon
, BALLOON
)
656 * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on
657 * pages allocated with __GFP_ACCOUNT. It gets cleared on page free.
659 #define PAGE_KMEMCG_MAPCOUNT_VALUE (-512)
660 PAGE_MAPCOUNT_OPS(Kmemcg
, KMEMCG
)
662 extern bool is_free_buddy_page(struct page
*page
);
664 __PAGEFLAG(Isolated
, isolated
, PF_ANY
);
667 * If network-based swap is enabled, sl*b must keep track of whether pages
668 * were allocated from pfmemalloc reserves.
670 static inline int PageSlabPfmemalloc(struct page
*page
)
672 VM_BUG_ON_PAGE(!PageSlab(page
), page
);
673 return PageActive(page
);
676 static inline void SetPageSlabPfmemalloc(struct page
*page
)
678 VM_BUG_ON_PAGE(!PageSlab(page
), page
);
682 static inline void __ClearPageSlabPfmemalloc(struct page
*page
)
684 VM_BUG_ON_PAGE(!PageSlab(page
), page
);
685 __ClearPageActive(page
);
688 static inline void ClearPageSlabPfmemalloc(struct page
*page
)
690 VM_BUG_ON_PAGE(!PageSlab(page
), page
);
691 ClearPageActive(page
);
695 #define __PG_MLOCKED (1UL << PG_mlocked)
697 #define __PG_MLOCKED 0
701 * Flags checked when a page is freed. Pages being freed should not have
702 * these flags set. It they are, there is a problem.
704 #define PAGE_FLAGS_CHECK_AT_FREE \
705 (1UL << PG_lru | 1UL << PG_locked | \
706 1UL << PG_private | 1UL << PG_private_2 | \
707 1UL << PG_writeback | 1UL << PG_reserved | \
708 1UL << PG_slab | 1UL << PG_swapcache | 1UL << PG_active | \
709 1UL << PG_unevictable | __PG_MLOCKED)
712 * Flags checked when a page is prepped for return by the page allocator.
713 * Pages being prepped should not have these flags set. It they are set,
714 * there has been a kernel bug or struct page corruption.
716 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
717 * alloc-free cycle to prevent from reusing the page.
719 #define PAGE_FLAGS_CHECK_AT_PREP \
720 (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
722 #define PAGE_FLAGS_PRIVATE \
723 (1UL << PG_private | 1UL << PG_private_2)
725 * page_has_private - Determine if page has private stuff
726 * @page: The page to be checked
728 * Determine if a page has private stuff, indicating that release routines
729 * should be invoked upon it.
731 static inline int page_has_private(struct page
*page
)
733 return !!(page
->flags
& PAGE_FLAGS_PRIVATE
);
739 #undef PF_NO_COMPOUND
740 #endif /* !__GENERATING_BOUNDS_H */
742 #endif /* PAGE_FLAGS_H */
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