1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Macros for manipulating and testing page->flags
4 */
5
6 #ifndef PAGE_FLAGS_H
7 #define PAGE_FLAGS_H
8
9 #include <linux/types.h>
10 #include <linux/bug.h>
11 #include <linux/mmdebug.h>
12 #ifndef __GENERATING_BOUNDS_H
13 #include <linux/mm_types.h>
14 #include <generated/bounds.h>
15 #endif /* !__GENERATING_BOUNDS_H */
16
17 /*
18 * Various page->flags bits:
19 *
20 * PG_reserved is set for special pages. The "struct page" of such a page
21 * should in general not be touched (e.g. set dirty) except by its owner.
22 * Pages marked as PG_reserved include:
23 * - Pages part of the kernel image (including vDSO) and similar (e.g. BIOS,
24 * initrd, HW tables)
25 * - Pages reserved or allocated early during boot (before the page allocator
26 * was initialized). This includes (depending on the architecture) the
27 * initial vmemmap, initial page tables, crashkernel, elfcorehdr, and much
28 * much more. Once (if ever) freed, PG_reserved is cleared and they will
29 * be given to the page allocator.
30 * - Pages falling into physical memory gaps - not IORESOURCE_SYSRAM. Trying
31 * to read/write these pages might end badly. Don't touch!
32 * - The zero page(s)
33 * - Pages allocated in the context of kexec/kdump (loaded kernel image,
34 * control pages, vmcoreinfo)
35 * - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are
36 * not marked PG_reserved (as they might be in use by somebody else who does
37 * not respect the caching strategy).
38 * - MCA pages on ia64
39 * - Pages holding CPU notes for POWER Firmware Assisted Dump
40 * - Device memory (e.g. PMEM, DAX, HMM)
41 * Some PG_reserved pages will be excluded from the hibernation image.
42 * PG_reserved does in general not hinder anybody from dumping or swapping
43 * and is no longer required for remap_pfn_range(). ioremap might require it.
44 * Consequently, PG_reserved for a page mapped into user space can indicate
45 * the zero page, the vDSO, MMIO pages or device memory.
46 *
47 * The PG_private bitflag is set on pagecache pages if they contain filesystem
48 * specific data (which is normally at page->private). It can be used by
49 * private allocations for its own usage.
50 *
51 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
52 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
53 * is set before writeback starts and cleared when it finishes.
54 *
55 * PG_locked also pins a page in pagecache, and blocks truncation of the file
56 * while it is held.
57 *
58 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
59 * to become unlocked.
60 *
61 * PG_swapbacked is set when a page uses swap as a backing storage. This are
62 * usually PageAnon or shmem pages but please note that even anonymous pages
63 * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as
64 * a result of MADV_FREE).
65 *
66 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
67 * file-backed pagecache (see mm/vmscan.c).
68 *
69 * PG_arch_1 is an architecture specific page state bit. The generic code
70 * guarantees that this bit is cleared for a page when it first is entered into
71 * the page cache.
72 *
73 * PG_hwpoison indicates that a page got corrupted in hardware and contains
74 * data with incorrect ECC bits that triggered a machine check. Accessing is
75 * not safe since it may cause another machine check. Don't touch!
76 */
77
78 /*
79 * Don't use the pageflags directly. Use the PageFoo macros.
80 *
81 * The page flags field is split into two parts, the main flags area
82 * which extends from the low bits upwards, and the fields area which
83 * extends from the high bits downwards.
84 *
85 * | FIELD | ... | FLAGS |
86 * N-1 ^ 0
87 * (NR_PAGEFLAGS)
88 *
89 * The fields area is reserved for fields mapping zone, node (for NUMA) and
90 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
91 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
92 */
93 enum pageflags {
94 PG_locked, /* Page is locked. Don't touch. */
95 PG_writeback, /* Page is under writeback */
96 PG_referenced,
97 PG_uptodate,
98 PG_dirty,
99 PG_lru,
100 PG_head, /* Must be in bit 6 */
101 PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
102 PG_active,
103 PG_workingset,
104 PG_owner_priv_1, /* Owner use. If pagecache, fs may use */
105 PG_owner_2, /* Owner use. If pagecache, fs may use */
106 PG_arch_1,
107 PG_reserved,
108 PG_private, /* If pagecache, has fs-private data */
109 PG_private_2, /* If pagecache, has fs aux data */
110 PG_reclaim, /* To be reclaimed asap */
111 PG_swapbacked, /* Page is backed by RAM/swap */
112 PG_unevictable, /* Page is "unevictable" */
113 #ifdef CONFIG_MMU
114 PG_mlocked, /* Page is vma mlocked */
115 #endif
116 #ifdef CONFIG_MEMORY_FAILURE
117 PG_hwpoison, /* hardware poisoned page. Don't touch */
118 #endif
119 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
120 PG_young,
121 PG_idle,
122 #endif
123 #ifdef CONFIG_ARCH_USES_PG_ARCH_2
124 PG_arch_2,
125 #endif
126 #ifdef CONFIG_ARCH_USES_PG_ARCH_3
127 PG_arch_3,
128 #endif
129 __NR_PAGEFLAGS,
130
131 PG_readahead = PG_reclaim,
132
133 /* Anonymous memory (and shmem) */
134 PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
135 /* Some filesystems */
136 PG_checked = PG_owner_priv_1,
137
138 /*
139 * Depending on the way an anonymous folio can be mapped into a page
140 * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped
141 * THP), PG_anon_exclusive may be set only for the head page or for
142 * tail pages of an anonymous folio. For now, we only expect it to be
143 * set on tail pages for PTE-mapped THP.
144 */
145 PG_anon_exclusive = PG_owner_2,
146
147 /*
148 * Set if all buffer heads in the folio are mapped.
149 * Filesystems which do not use BHs can use it for their own purpose.
150 */
151 PG_mappedtodisk = PG_owner_2,
152
153 /* Two page bits are conscripted by FS-Cache to maintain local caching
154 * state. These bits are set on pages belonging to the netfs's inodes
155 * when those inodes are being locally cached.
156 */
157 PG_fscache = PG_private_2, /* page backed by cache */
158
159 /* XEN */
160 /* Pinned in Xen as a read-only pagetable page. */
161 PG_pinned = PG_owner_priv_1,
162 /* Pinned as part of domain save (see xen_mm_pin_all()). */
163 PG_savepinned = PG_dirty,
164 /* Has a grant mapping of another (foreign) domain's page. */
165 PG_foreign = PG_owner_priv_1,
166 /* Remapped by swiotlb-xen. */
167 PG_xen_remapped = PG_owner_priv_1,
168
169 /* non-lru isolated movable page */
170 PG_isolated = PG_reclaim,
171
172 /* Only valid for buddy pages. Used to track pages that are reported */
173 PG_reported = PG_uptodate,
174
175 #ifdef CONFIG_MEMORY_HOTPLUG
176 /* For self-hosted memmap pages */
177 PG_vmemmap_self_hosted = PG_owner_priv_1,
178 #endif
179
180 /*
181 * Flags only valid for compound pages. Stored in first tail page's
182 * flags word. Cannot use the first 8 flags or any flag marked as
183 * PF_ANY.
184 */
185
186 /* At least one page in this folio has the hwpoison flag set */
187 PG_has_hwpoisoned = PG_active,
188 PG_large_rmappable = PG_workingset, /* anon or file-backed */
189 PG_partially_mapped = PG_reclaim, /* was identified to be partially mapped */
190 };
191
192 #define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1)
193
194 #ifndef __GENERATING_BOUNDS_H
195
196 #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
197 DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);
198
199 /*
200 * Return the real head page struct iff the @page is a fake head page, otherwise
201 * return the @page itself. See Documentation/mm/vmemmap_dedup.rst.
202 */
page_fixed_fake_head(const struct page * page)203 static __always_inline const struct page *page_fixed_fake_head(const struct page *page)
204 {
205 if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key))
206 return page;
207
208 /*
209 * Only addresses aligned with PAGE_SIZE of struct page may be fake head
210 * struct page. The alignment check aims to avoid access the fields (
211 * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly)
212 * cold cacheline in some cases.
213 */
214 if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) &&
215 test_bit(PG_head, &page->flags)) {
216 /*
217 * We can safely access the field of the @page[1] with PG_head
218 * because the @page is a compound page composed with at least
219 * two contiguous pages.
220 */
221 unsigned long head = READ_ONCE(page[1].compound_head);
222
223 if (likely(head & 1))
224 return (const struct page *)(head - 1);
225 }
226 return page;
227 }
228 #else
page_fixed_fake_head(const struct page * page)229 static inline const struct page *page_fixed_fake_head(const struct page *page)
230 {
231 return page;
232 }
233 #endif
234
page_is_fake_head(const struct page * page)235 static __always_inline int page_is_fake_head(const struct page *page)
236 {
237 return page_fixed_fake_head(page) != page;
238 }
239
_compound_head(const struct page * page)240 static __always_inline unsigned long _compound_head(const struct page *page)
241 {
242 unsigned long head = READ_ONCE(page->compound_head);
243
244 if (unlikely(head & 1))
245 return head - 1;
246 return (unsigned long)page_fixed_fake_head(page);
247 }
248
249 #define compound_head(page) ((typeof(page))_compound_head(page))
250
251 /**
252 * page_folio - Converts from page to folio.
253 * @p: The page.
254 *
255 * Every page is part of a folio. This function cannot be called on a
256 * NULL pointer.
257 *
258 * Context: No reference, nor lock is required on @page. If the caller
259 * does not hold a reference, this call may race with a folio split, so
260 * it should re-check the folio still contains this page after gaining
261 * a reference on the folio.
262 * Return: The folio which contains this page.
263 */
264 #define page_folio(p) (_Generic((p), \
265 const struct page *: (const struct folio *)_compound_head(p), \
266 struct page *: (struct folio *)_compound_head(p)))
267
268 /**
269 * folio_page - Return a page from a folio.
270 * @folio: The folio.
271 * @n: The page number to return.
272 *
273 * @n is relative to the start of the folio. This function does not
274 * check that the page number lies within @folio; the caller is presumed
275 * to have a reference to the page.
276 */
277 #define folio_page(folio, n) nth_page(&(folio)->page, n)
278
PageTail(const struct page * page)279 static __always_inline int PageTail(const struct page *page)
280 {
281 return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page);
282 }
283
PageCompound(const struct page * page)284 static __always_inline int PageCompound(const struct page *page)
285 {
286 return test_bit(PG_head, &page->flags) ||
287 READ_ONCE(page->compound_head) & 1;
288 }
289
290 #define PAGE_POISON_PATTERN -1l
PagePoisoned(const struct page * page)291 static inline int PagePoisoned(const struct page *page)
292 {
293 return READ_ONCE(page->flags) == PAGE_POISON_PATTERN;
294 }
295
296 #ifdef CONFIG_DEBUG_VM
297 void page_init_poison(struct page *page, size_t size);
298 #else
page_init_poison(struct page * page,size_t size)299 static inline void page_init_poison(struct page *page, size_t size)
300 {
301 }
302 #endif
303
const_folio_flags(const struct folio * folio,unsigned n)304 static const unsigned long *const_folio_flags(const struct folio *folio,
305 unsigned n)
306 {
307 const struct page *page = &folio->page;
308
309 VM_BUG_ON_PGFLAGS(page->compound_head & 1, page);
310 VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
311 return &page[n].flags;
312 }
313
folio_flags(struct folio * folio,unsigned n)314 static unsigned long *folio_flags(struct folio *folio, unsigned n)
315 {
316 struct page *page = &folio->page;
317
318 VM_BUG_ON_PGFLAGS(page->compound_head & 1, page);
319 VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
320 return &page[n].flags;
321 }
322
323 /*
324 * Page flags policies wrt compound pages
325 *
326 * PF_POISONED_CHECK
327 * check if this struct page poisoned/uninitialized
328 *
329 * PF_ANY:
330 * the page flag is relevant for small, head and tail pages.
331 *
332 * PF_HEAD:
333 * for compound page all operations related to the page flag applied to
334 * head page.
335 *
336 * PF_NO_TAIL:
337 * modifications of the page flag must be done on small or head pages,
338 * checks can be done on tail pages too.
339 *
340 * PF_NO_COMPOUND:
341 * the page flag is not relevant for compound pages.
342 *
343 * PF_SECOND:
344 * the page flag is stored in the first tail page.
345 */
346 #define PF_POISONED_CHECK(page) ({ \
347 VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
348 page; })
349 #define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
350 #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
351 #define PF_NO_TAIL(page, enforce) ({ \
352 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
353 PF_POISONED_CHECK(compound_head(page)); })
354 #define PF_NO_COMPOUND(page, enforce) ({ \
355 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
356 PF_POISONED_CHECK(page); })
357 #define PF_SECOND(page, enforce) ({ \
358 VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
359 PF_POISONED_CHECK(&page[1]); })
360
361 /* Which page is the flag stored in */
362 #define FOLIO_PF_ANY 0
363 #define FOLIO_PF_HEAD 0
364 #define FOLIO_PF_NO_TAIL 0
365 #define FOLIO_PF_NO_COMPOUND 0
366 #define FOLIO_PF_SECOND 1
367
368 #define FOLIO_HEAD_PAGE 0
369 #define FOLIO_SECOND_PAGE 1
370
371 /*
372 * Macros to create function definitions for page flags
373 */
374 #define FOLIO_TEST_FLAG(name, page) \
375 static __always_inline bool folio_test_##name(const struct folio *folio) \
376 { return test_bit(PG_##name, const_folio_flags(folio, page)); }
377
378 #define FOLIO_SET_FLAG(name, page) \
379 static __always_inline void folio_set_##name(struct folio *folio) \
380 { set_bit(PG_##name, folio_flags(folio, page)); }
381
382 #define FOLIO_CLEAR_FLAG(name, page) \
383 static __always_inline void folio_clear_##name(struct folio *folio) \
384 { clear_bit(PG_##name, folio_flags(folio, page)); }
385
386 #define __FOLIO_SET_FLAG(name, page) \
387 static __always_inline void __folio_set_##name(struct folio *folio) \
388 { __set_bit(PG_##name, folio_flags(folio, page)); }
389
390 #define __FOLIO_CLEAR_FLAG(name, page) \
391 static __always_inline void __folio_clear_##name(struct folio *folio) \
392 { __clear_bit(PG_##name, folio_flags(folio, page)); }
393
394 #define FOLIO_TEST_SET_FLAG(name, page) \
395 static __always_inline bool folio_test_set_##name(struct folio *folio) \
396 { return test_and_set_bit(PG_##name, folio_flags(folio, page)); }
397
398 #define FOLIO_TEST_CLEAR_FLAG(name, page) \
399 static __always_inline bool folio_test_clear_##name(struct folio *folio) \
400 { return test_and_clear_bit(PG_##name, folio_flags(folio, page)); }
401
402 #define FOLIO_FLAG(name, page) \
403 FOLIO_TEST_FLAG(name, page) \
404 FOLIO_SET_FLAG(name, page) \
405 FOLIO_CLEAR_FLAG(name, page)
406
407 #define TESTPAGEFLAG(uname, lname, policy) \
408 FOLIO_TEST_FLAG(lname, FOLIO_##policy) \
409 static __always_inline int Page##uname(const struct page *page) \
410 { return test_bit(PG_##lname, &policy(page, 0)->flags); }
411
412 #define SETPAGEFLAG(uname, lname, policy) \
413 FOLIO_SET_FLAG(lname, FOLIO_##policy) \
414 static __always_inline void SetPage##uname(struct page *page) \
415 { set_bit(PG_##lname, &policy(page, 1)->flags); }
416
417 #define CLEARPAGEFLAG(uname, lname, policy) \
418 FOLIO_CLEAR_FLAG(lname, FOLIO_##policy) \
419 static __always_inline void ClearPage##uname(struct page *page) \
420 { clear_bit(PG_##lname, &policy(page, 1)->flags); }
421
422 #define __SETPAGEFLAG(uname, lname, policy) \
423 __FOLIO_SET_FLAG(lname, FOLIO_##policy) \
424 static __always_inline void __SetPage##uname(struct page *page) \
425 { __set_bit(PG_##lname, &policy(page, 1)->flags); }
426
427 #define __CLEARPAGEFLAG(uname, lname, policy) \
428 __FOLIO_CLEAR_FLAG(lname, FOLIO_##policy) \
429 static __always_inline void __ClearPage##uname(struct page *page) \
430 { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
431
432 #define TESTSETFLAG(uname, lname, policy) \
433 FOLIO_TEST_SET_FLAG(lname, FOLIO_##policy) \
434 static __always_inline int TestSetPage##uname(struct page *page) \
435 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
436
437 #define TESTCLEARFLAG(uname, lname, policy) \
438 FOLIO_TEST_CLEAR_FLAG(lname, FOLIO_##policy) \
439 static __always_inline int TestClearPage##uname(struct page *page) \
440 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
441
442 #define PAGEFLAG(uname, lname, policy) \
443 TESTPAGEFLAG(uname, lname, policy) \
444 SETPAGEFLAG(uname, lname, policy) \
445 CLEARPAGEFLAG(uname, lname, policy)
446
447 #define __PAGEFLAG(uname, lname, policy) \
448 TESTPAGEFLAG(uname, lname, policy) \
449 __SETPAGEFLAG(uname, lname, policy) \
450 __CLEARPAGEFLAG(uname, lname, policy)
451
452 #define TESTSCFLAG(uname, lname, policy) \
453 TESTSETFLAG(uname, lname, policy) \
454 TESTCLEARFLAG(uname, lname, policy)
455
456 #define FOLIO_TEST_FLAG_FALSE(name) \
457 static inline bool folio_test_##name(const struct folio *folio) \
458 { return false; }
459 #define FOLIO_SET_FLAG_NOOP(name) \
460 static inline void folio_set_##name(struct folio *folio) { }
461 #define FOLIO_CLEAR_FLAG_NOOP(name) \
462 static inline void folio_clear_##name(struct folio *folio) { }
463 #define __FOLIO_SET_FLAG_NOOP(name) \
464 static inline void __folio_set_##name(struct folio *folio) { }
465 #define __FOLIO_CLEAR_FLAG_NOOP(name) \
466 static inline void __folio_clear_##name(struct folio *folio) { }
467 #define FOLIO_TEST_SET_FLAG_FALSE(name) \
468 static inline bool folio_test_set_##name(struct folio *folio) \
469 { return false; }
470 #define FOLIO_TEST_CLEAR_FLAG_FALSE(name) \
471 static inline bool folio_test_clear_##name(struct folio *folio) \
472 { return false; }
473
474 #define FOLIO_FLAG_FALSE(name) \
475 FOLIO_TEST_FLAG_FALSE(name) \
476 FOLIO_SET_FLAG_NOOP(name) \
477 FOLIO_CLEAR_FLAG_NOOP(name)
478
479 #define TESTPAGEFLAG_FALSE(uname, lname) \
480 FOLIO_TEST_FLAG_FALSE(lname) \
481 static inline int Page##uname(const struct page *page) { return 0; }
482
483 #define SETPAGEFLAG_NOOP(uname, lname) \
484 FOLIO_SET_FLAG_NOOP(lname) \
485 static inline void SetPage##uname(struct page *page) { }
486
487 #define CLEARPAGEFLAG_NOOP(uname, lname) \
488 FOLIO_CLEAR_FLAG_NOOP(lname) \
489 static inline void ClearPage##uname(struct page *page) { }
490
491 #define __CLEARPAGEFLAG_NOOP(uname, lname) \
492 __FOLIO_CLEAR_FLAG_NOOP(lname) \
493 static inline void __ClearPage##uname(struct page *page) { }
494
495 #define TESTSETFLAG_FALSE(uname, lname) \
496 FOLIO_TEST_SET_FLAG_FALSE(lname) \
497 static inline int TestSetPage##uname(struct page *page) { return 0; }
498
499 #define TESTCLEARFLAG_FALSE(uname, lname) \
500 FOLIO_TEST_CLEAR_FLAG_FALSE(lname) \
501 static inline int TestClearPage##uname(struct page *page) { return 0; }
502
503 #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \
504 SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)
505
506 #define TESTSCFLAG_FALSE(uname, lname) \
507 TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)
508
509 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
510 FOLIO_FLAG(waiters, FOLIO_HEAD_PAGE)
511 FOLIO_FLAG(referenced, FOLIO_HEAD_PAGE)
512 FOLIO_TEST_CLEAR_FLAG(referenced, FOLIO_HEAD_PAGE)
513 __FOLIO_SET_FLAG(referenced, FOLIO_HEAD_PAGE)
514 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
515 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
516 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
517 TESTCLEARFLAG(LRU, lru, PF_HEAD)
518 FOLIO_FLAG(active, FOLIO_HEAD_PAGE)
519 __FOLIO_CLEAR_FLAG(active, FOLIO_HEAD_PAGE)
520 FOLIO_TEST_CLEAR_FLAG(active, FOLIO_HEAD_PAGE)
521 PAGEFLAG(Workingset, workingset, PF_HEAD)
522 TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
523 PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
524
525 /* Xen */
526 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
527 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
528 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
529 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
PAGEFLAG(XenRemapped,xen_remapped,PF_NO_COMPOUND)530 PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
531 TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
532
533 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
534 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
535 __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
536 FOLIO_FLAG(swapbacked, FOLIO_HEAD_PAGE)
537 __FOLIO_CLEAR_FLAG(swapbacked, FOLIO_HEAD_PAGE)
538 __FOLIO_SET_FLAG(swapbacked, FOLIO_HEAD_PAGE)
539
540 /*
541 * Private page markings that may be used by the filesystem that owns the page
542 * for its own purposes.
543 * - PG_private and PG_private_2 cause release_folio() and co to be invoked
544 */
545 PAGEFLAG(Private, private, PF_ANY)
546 FOLIO_FLAG(private_2, FOLIO_HEAD_PAGE)
547
548 /* owner_2 can be set on tail pages for anon memory */
549 FOLIO_FLAG(owner_2, FOLIO_HEAD_PAGE)
550
551 /*
552 * Only test-and-set exist for PG_writeback. The unconditional operators are
553 * risky: they bypass page accounting.
554 */
555 TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
556 TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
557 FOLIO_FLAG(mappedtodisk, FOLIO_HEAD_PAGE)
558
559 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
560 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
561 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
562 FOLIO_FLAG(readahead, FOLIO_HEAD_PAGE)
563 FOLIO_TEST_CLEAR_FLAG(readahead, FOLIO_HEAD_PAGE)
564
565 #ifdef CONFIG_HIGHMEM
566 /*
567 * Must use a macro here due to header dependency issues. page_zone() is not
568 * available at this point.
569 */
570 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
571 #define folio_test_highmem(__f) is_highmem_idx(folio_zonenum(__f))
572 #else
573 PAGEFLAG_FALSE(HighMem, highmem)
574 #endif
575
576 #ifdef CONFIG_SWAP
577 static __always_inline bool folio_test_swapcache(const struct folio *folio)
578 {
579 return folio_test_swapbacked(folio) &&
580 test_bit(PG_swapcache, const_folio_flags(folio, 0));
581 }
582
FOLIO_SET_FLAG(swapcache,FOLIO_HEAD_PAGE)583 FOLIO_SET_FLAG(swapcache, FOLIO_HEAD_PAGE)
584 FOLIO_CLEAR_FLAG(swapcache, FOLIO_HEAD_PAGE)
585 #else
586 FOLIO_FLAG_FALSE(swapcache)
587 #endif
588
589 FOLIO_FLAG(unevictable, FOLIO_HEAD_PAGE)
590 __FOLIO_CLEAR_FLAG(unevictable, FOLIO_HEAD_PAGE)
591 FOLIO_TEST_CLEAR_FLAG(unevictable, FOLIO_HEAD_PAGE)
592
593 #ifdef CONFIG_MMU
594 FOLIO_FLAG(mlocked, FOLIO_HEAD_PAGE)
595 __FOLIO_CLEAR_FLAG(mlocked, FOLIO_HEAD_PAGE)
596 FOLIO_TEST_CLEAR_FLAG(mlocked, FOLIO_HEAD_PAGE)
597 FOLIO_TEST_SET_FLAG(mlocked, FOLIO_HEAD_PAGE)
598 #else
599 FOLIO_FLAG_FALSE(mlocked)
600 __FOLIO_CLEAR_FLAG_NOOP(mlocked)
601 FOLIO_TEST_CLEAR_FLAG_FALSE(mlocked)
602 FOLIO_TEST_SET_FLAG_FALSE(mlocked)
603 #endif
604
605 #ifdef CONFIG_MEMORY_FAILURE
606 PAGEFLAG(HWPoison, hwpoison, PF_ANY)
607 TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
608 #define __PG_HWPOISON (1UL << PG_hwpoison)
609 #else
610 PAGEFLAG_FALSE(HWPoison, hwpoison)
611 #define __PG_HWPOISON 0
612 #endif
613
614 #ifdef CONFIG_PAGE_IDLE_FLAG
615 #ifdef CONFIG_64BIT
616 FOLIO_TEST_FLAG(young, FOLIO_HEAD_PAGE)
617 FOLIO_SET_FLAG(young, FOLIO_HEAD_PAGE)
618 FOLIO_TEST_CLEAR_FLAG(young, FOLIO_HEAD_PAGE)
619 FOLIO_FLAG(idle, FOLIO_HEAD_PAGE)
620 #endif
621 /* See page_idle.h for !64BIT workaround */
622 #else /* !CONFIG_PAGE_IDLE_FLAG */
623 FOLIO_FLAG_FALSE(young)
624 FOLIO_TEST_CLEAR_FLAG_FALSE(young)
625 FOLIO_FLAG_FALSE(idle)
626 #endif
627
628 /*
629 * PageReported() is used to track reported free pages within the Buddy
630 * allocator. We can use the non-atomic version of the test and set
631 * operations as both should be shielded with the zone lock to prevent
632 * any possible races on the setting or clearing of the bit.
633 */
634 __PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
635
636 #ifdef CONFIG_MEMORY_HOTPLUG
637 PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY)
638 #else
639 PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted)
640 #endif
641
642 /*
643 * On an anonymous folio mapped into a user virtual memory area,
644 * folio->mapping points to its anon_vma, not to a struct address_space;
645 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
646 *
647 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
648 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
649 * bit; and then folio->mapping points, not to an anon_vma, but to a private
650 * structure which KSM associates with that merged page. See ksm.h.
651 *
652 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
653 * page and then folio->mapping points to a struct movable_operations.
654 *
655 * Please note that, confusingly, "folio_mapping" refers to the inode
656 * address_space which maps the folio from disk; whereas "folio_mapped"
657 * refers to user virtual address space into which the folio is mapped.
658 *
659 * For slab pages, since slab reuses the bits in struct page to store its
660 * internal states, the folio->mapping does not exist as such, nor do
661 * these flags below. So in order to avoid testing non-existent bits,
662 * please make sure that folio_test_slab(folio) actually evaluates to
663 * false before calling the following functions (e.g., folio_test_anon).
664 * See mm/slab.h.
665 */
666 #define PAGE_MAPPING_ANON 0x1
667 #define PAGE_MAPPING_MOVABLE 0x2
668 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
669 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
670
671 /*
672 * Different with flags above, this flag is used only for fsdax mode. It
673 * indicates that this page->mapping is now under reflink case.
674 */
675 #define PAGE_MAPPING_DAX_SHARED ((void *)0x1)
676
677 static __always_inline bool folio_mapping_flags(const struct folio *folio)
678 {
679 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0;
680 }
681
PageMappingFlags(const struct page * page)682 static __always_inline bool PageMappingFlags(const struct page *page)
683 {
684 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
685 }
686
folio_test_anon(const struct folio * folio)687 static __always_inline bool folio_test_anon(const struct folio *folio)
688 {
689 return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0;
690 }
691
PageAnonNotKsm(const struct page * page)692 static __always_inline bool PageAnonNotKsm(const struct page *page)
693 {
694 unsigned long flags = (unsigned long)page_folio(page)->mapping;
695
696 return (flags & PAGE_MAPPING_FLAGS) == PAGE_MAPPING_ANON;
697 }
698
PageAnon(const struct page * page)699 static __always_inline bool PageAnon(const struct page *page)
700 {
701 return folio_test_anon(page_folio(page));
702 }
703
__folio_test_movable(const struct folio * folio)704 static __always_inline bool __folio_test_movable(const struct folio *folio)
705 {
706 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
707 PAGE_MAPPING_MOVABLE;
708 }
709
__PageMovable(const struct page * page)710 static __always_inline bool __PageMovable(const struct page *page)
711 {
712 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
713 PAGE_MAPPING_MOVABLE;
714 }
715
716 #ifdef CONFIG_KSM
717 /*
718 * A KSM page is one of those write-protected "shared pages" or "merged pages"
719 * which KSM maps into multiple mms, wherever identical anonymous page content
720 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
721 * anon_vma, but to that page's node of the stable tree.
722 */
folio_test_ksm(const struct folio * folio)723 static __always_inline bool folio_test_ksm(const struct folio *folio)
724 {
725 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
726 PAGE_MAPPING_KSM;
727 }
728 #else
729 FOLIO_TEST_FLAG_FALSE(ksm)
730 #endif
731
732 u64 stable_page_flags(const struct page *page);
733
734 /**
735 * folio_xor_flags_has_waiters - Change some folio flags.
736 * @folio: The folio.
737 * @mask: Bits set in this word will be changed.
738 *
739 * This must only be used for flags which are changed with the folio
740 * lock held. For example, it is unsafe to use for PG_dirty as that
741 * can be set without the folio lock held. It can also only be used
742 * on flags which are in the range 0-6 as some of the implementations
743 * only affect those bits.
744 *
745 * Return: Whether there are tasks waiting on the folio.
746 */
folio_xor_flags_has_waiters(struct folio * folio,unsigned long mask)747 static inline bool folio_xor_flags_has_waiters(struct folio *folio,
748 unsigned long mask)
749 {
750 return xor_unlock_is_negative_byte(mask, folio_flags(folio, 0));
751 }
752
753 /**
754 * folio_test_uptodate - Is this folio up to date?
755 * @folio: The folio.
756 *
757 * The uptodate flag is set on a folio when every byte in the folio is
758 * at least as new as the corresponding bytes on storage. Anonymous
759 * and CoW folios are always uptodate. If the folio is not uptodate,
760 * some of the bytes in it may be; see the is_partially_uptodate()
761 * address_space operation.
762 */
folio_test_uptodate(const struct folio * folio)763 static inline bool folio_test_uptodate(const struct folio *folio)
764 {
765 bool ret = test_bit(PG_uptodate, const_folio_flags(folio, 0));
766 /*
767 * Must ensure that the data we read out of the folio is loaded
768 * _after_ we've loaded folio->flags to check the uptodate bit.
769 * We can skip the barrier if the folio is not uptodate, because
770 * we wouldn't be reading anything from it.
771 *
772 * See folio_mark_uptodate() for the other side of the story.
773 */
774 if (ret)
775 smp_rmb();
776
777 return ret;
778 }
779
PageUptodate(const struct page * page)780 static inline bool PageUptodate(const struct page *page)
781 {
782 return folio_test_uptodate(page_folio(page));
783 }
784
__folio_mark_uptodate(struct folio * folio)785 static __always_inline void __folio_mark_uptodate(struct folio *folio)
786 {
787 smp_wmb();
788 __set_bit(PG_uptodate, folio_flags(folio, 0));
789 }
790
folio_mark_uptodate(struct folio * folio)791 static __always_inline void folio_mark_uptodate(struct folio *folio)
792 {
793 /*
794 * Memory barrier must be issued before setting the PG_uptodate bit,
795 * so that all previous stores issued in order to bring the folio
796 * uptodate are actually visible before folio_test_uptodate becomes true.
797 */
798 smp_wmb();
799 set_bit(PG_uptodate, folio_flags(folio, 0));
800 }
801
__SetPageUptodate(struct page * page)802 static __always_inline void __SetPageUptodate(struct page *page)
803 {
804 __folio_mark_uptodate((struct folio *)page);
805 }
806
SetPageUptodate(struct page * page)807 static __always_inline void SetPageUptodate(struct page *page)
808 {
809 folio_mark_uptodate((struct folio *)page);
810 }
811
812 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
813
814 void __folio_start_writeback(struct folio *folio, bool keep_write);
815 void set_page_writeback(struct page *page);
816
817 #define folio_start_writeback(folio) \
818 __folio_start_writeback(folio, false)
819 #define folio_start_writeback_keepwrite(folio) \
820 __folio_start_writeback(folio, true)
821
folio_test_head(const struct folio * folio)822 static __always_inline bool folio_test_head(const struct folio *folio)
823 {
824 return test_bit(PG_head, const_folio_flags(folio, FOLIO_PF_ANY));
825 }
826
PageHead(const struct page * page)827 static __always_inline int PageHead(const struct page *page)
828 {
829 PF_POISONED_CHECK(page);
830 return test_bit(PG_head, &page->flags) && !page_is_fake_head(page);
831 }
832
__SETPAGEFLAG(Head,head,PF_ANY)833 __SETPAGEFLAG(Head, head, PF_ANY)
834 __CLEARPAGEFLAG(Head, head, PF_ANY)
835 CLEARPAGEFLAG(Head, head, PF_ANY)
836
837 /**
838 * folio_test_large() - Does this folio contain more than one page?
839 * @folio: The folio to test.
840 *
841 * Return: True if the folio is larger than one page.
842 */
843 static inline bool folio_test_large(const struct folio *folio)
844 {
845 return folio_test_head(folio);
846 }
847
set_compound_head(struct page * page,struct page * head)848 static __always_inline void set_compound_head(struct page *page, struct page *head)
849 {
850 WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
851 }
852
clear_compound_head(struct page * page)853 static __always_inline void clear_compound_head(struct page *page)
854 {
855 WRITE_ONCE(page->compound_head, 0);
856 }
857
858 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
ClearPageCompound(struct page * page)859 static inline void ClearPageCompound(struct page *page)
860 {
861 BUG_ON(!PageHead(page));
862 ClearPageHead(page);
863 }
FOLIO_FLAG(large_rmappable,FOLIO_SECOND_PAGE)864 FOLIO_FLAG(large_rmappable, FOLIO_SECOND_PAGE)
865 FOLIO_FLAG(partially_mapped, FOLIO_SECOND_PAGE)
866 #else
867 FOLIO_FLAG_FALSE(large_rmappable)
868 FOLIO_FLAG_FALSE(partially_mapped)
869 #endif
870
871 #define PG_head_mask ((1UL << PG_head))
872
873 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
874 /*
875 * PageHuge() only returns true for hugetlbfs pages, but not for
876 * normal or transparent huge pages.
877 *
878 * PageTransHuge() returns true for both transparent huge and
879 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
880 * called only in the core VM paths where hugetlbfs pages can't exist.
881 */
882 static inline int PageTransHuge(const struct page *page)
883 {
884 VM_BUG_ON_PAGE(PageTail(page), page);
885 return PageHead(page);
886 }
887
888 /*
889 * PageTransCompound returns true for both transparent huge pages
890 * and hugetlbfs pages, so it should only be called when it's known
891 * that hugetlbfs pages aren't involved.
892 */
PageTransCompound(const struct page * page)893 static inline int PageTransCompound(const struct page *page)
894 {
895 return PageCompound(page);
896 }
897
898 /*
899 * PageTransTail returns true for both transparent huge pages
900 * and hugetlbfs pages, so it should only be called when it's known
901 * that hugetlbfs pages aren't involved.
902 */
PageTransTail(const struct page * page)903 static inline int PageTransTail(const struct page *page)
904 {
905 return PageTail(page);
906 }
907 #else
908 TESTPAGEFLAG_FALSE(TransHuge, transhuge)
909 TESTPAGEFLAG_FALSE(TransCompound, transcompound)
910 TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap)
911 TESTPAGEFLAG_FALSE(TransTail, transtail)
912 #endif
913
914 #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
915 /*
916 * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the
917 * compound page.
918 *
919 * This flag is set by hwpoison handler. Cleared by THP split or free page.
920 */
921 PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
922 TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
923 #else
924 PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
925 TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
926 #endif
927
928 /*
929 * For pages that do not use mapcount, page_type may be used.
930 * The low 24 bits of pagetype may be used for your own purposes, as long
931 * as you are careful to not affect the top 8 bits. The low bits of
932 * pagetype will be overwritten when you clear the page_type from the page.
933 */
934 enum pagetype {
935 /* 0x00-0x7f are positive numbers, ie mapcount */
936 /* Reserve 0x80-0xef for mapcount overflow. */
937 PGTY_buddy = 0xf0,
938 PGTY_offline = 0xf1,
939 PGTY_table = 0xf2,
940 PGTY_guard = 0xf3,
941 PGTY_hugetlb = 0xf4,
942 PGTY_slab = 0xf5,
943 PGTY_zsmalloc = 0xf6,
944 PGTY_unaccepted = 0xf7,
945
946 PGTY_mapcount_underflow = 0xff
947 };
948
page_type_has_type(int page_type)949 static inline bool page_type_has_type(int page_type)
950 {
951 return page_type < (PGTY_mapcount_underflow << 24);
952 }
953
954 /* This takes a mapcount which is one more than page->_mapcount */
page_mapcount_is_type(unsigned int mapcount)955 static inline bool page_mapcount_is_type(unsigned int mapcount)
956 {
957 return page_type_has_type(mapcount - 1);
958 }
959
page_has_type(const struct page * page)960 static inline bool page_has_type(const struct page *page)
961 {
962 return page_mapcount_is_type(data_race(page->page_type));
963 }
964
965 #define FOLIO_TYPE_OPS(lname, fname) \
966 static __always_inline bool folio_test_##fname(const struct folio *folio) \
967 { \
968 return data_race(folio->page.page_type >> 24) == PGTY_##lname; \
969 } \
970 static __always_inline void __folio_set_##fname(struct folio *folio) \
971 { \
972 if (folio_test_##fname(folio)) \
973 return; \
974 VM_BUG_ON_FOLIO(data_race(folio->page.page_type) != UINT_MAX, \
975 folio); \
976 folio->page.page_type = (unsigned int)PGTY_##lname << 24; \
977 } \
978 static __always_inline void __folio_clear_##fname(struct folio *folio) \
979 { \
980 if (folio->page.page_type == UINT_MAX) \
981 return; \
982 VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio); \
983 folio->page.page_type = UINT_MAX; \
984 }
985
986 #define PAGE_TYPE_OPS(uname, lname, fname) \
987 FOLIO_TYPE_OPS(lname, fname) \
988 static __always_inline int Page##uname(const struct page *page) \
989 { \
990 return data_race(page->page_type >> 24) == PGTY_##lname; \
991 } \
992 static __always_inline void __SetPage##uname(struct page *page) \
993 { \
994 if (Page##uname(page)) \
995 return; \
996 VM_BUG_ON_PAGE(data_race(page->page_type) != UINT_MAX, page); \
997 page->page_type = (unsigned int)PGTY_##lname << 24; \
998 } \
999 static __always_inline void __ClearPage##uname(struct page *page) \
1000 { \
1001 if (page->page_type == UINT_MAX) \
1002 return; \
1003 VM_BUG_ON_PAGE(!Page##uname(page), page); \
1004 page->page_type = UINT_MAX; \
1005 }
1006
1007 /*
1008 * PageBuddy() indicates that the page is free and in the buddy system
1009 * (see mm/page_alloc.c).
1010 */
1011 PAGE_TYPE_OPS(Buddy, buddy, buddy)
1012
1013 /*
1014 * PageOffline() indicates that the page is logically offline although the
1015 * containing section is online. (e.g. inflated in a balloon driver or
1016 * not onlined when onlining the section).
1017 * The content of these pages is effectively stale. Such pages should not
1018 * be touched (read/write/dump/save) except by their owner.
1019 *
1020 * When a memory block gets onlined, all pages are initialized with a
1021 * refcount of 1 and PageOffline(). generic_online_page() will
1022 * take care of clearing PageOffline().
1023 *
1024 * If a driver wants to allow to offline unmovable PageOffline() pages without
1025 * putting them back to the buddy, it can do so via the memory notifier by
1026 * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the
1027 * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline()
1028 * pages (now with a reference count of zero) are treated like free (unmanaged)
1029 * pages, allowing the containing memory block to get offlined. A driver that
1030 * relies on this feature is aware that re-onlining the memory block will
1031 * require not giving them to the buddy via generic_online_page().
1032 *
1033 * Memory offlining code will not adjust the managed page count for any
1034 * PageOffline() pages, treating them like they were never exposed to the
1035 * buddy using generic_online_page().
1036 *
1037 * There are drivers that mark a page PageOffline() and expect there won't be
1038 * any further access to page content. PFN walkers that read content of random
1039 * pages should check PageOffline() and synchronize with such drivers using
1040 * page_offline_freeze()/page_offline_thaw().
1041 */
1042 PAGE_TYPE_OPS(Offline, offline, offline)
1043
1044 extern void page_offline_freeze(void);
1045 extern void page_offline_thaw(void);
1046 extern void page_offline_begin(void);
1047 extern void page_offline_end(void);
1048
1049 /*
1050 * Marks pages in use as page tables.
1051 */
PAGE_TYPE_OPS(Table,table,pgtable)1052 PAGE_TYPE_OPS(Table, table, pgtable)
1053
1054 /*
1055 * Marks guardpages used with debug_pagealloc.
1056 */
1057 PAGE_TYPE_OPS(Guard, guard, guard)
1058
1059 FOLIO_TYPE_OPS(slab, slab)
1060
1061 /**
1062 * PageSlab - Determine if the page belongs to the slab allocator
1063 * @page: The page to test.
1064 *
1065 * Context: Any context.
1066 * Return: True for slab pages, false for any other kind of page.
1067 */
1068 static inline bool PageSlab(const struct page *page)
1069 {
1070 return folio_test_slab(page_folio(page));
1071 }
1072
1073 #ifdef CONFIG_HUGETLB_PAGE
FOLIO_TYPE_OPS(hugetlb,hugetlb)1074 FOLIO_TYPE_OPS(hugetlb, hugetlb)
1075 #else
1076 FOLIO_TEST_FLAG_FALSE(hugetlb)
1077 #endif
1078
1079 PAGE_TYPE_OPS(Zsmalloc, zsmalloc, zsmalloc)
1080
1081 /*
1082 * Mark pages that has to be accepted before touched for the first time.
1083 *
1084 * Serialized with zone lock.
1085 */
1086 PAGE_TYPE_OPS(Unaccepted, unaccepted, unaccepted)
1087
1088 /**
1089 * PageHuge - Determine if the page belongs to hugetlbfs
1090 * @page: The page to test.
1091 *
1092 * Context: Any context.
1093 * Return: True for hugetlbfs pages, false for anon pages or pages
1094 * belonging to other filesystems.
1095 */
1096 static inline bool PageHuge(const struct page *page)
1097 {
1098 return folio_test_hugetlb(page_folio(page));
1099 }
1100
1101 /*
1102 * Check if a page is currently marked HWPoisoned. Note that this check is
1103 * best effort only and inherently racy: there is no way to synchronize with
1104 * failing hardware.
1105 */
is_page_hwpoison(const struct page * page)1106 static inline bool is_page_hwpoison(const struct page *page)
1107 {
1108 const struct folio *folio;
1109
1110 if (PageHWPoison(page))
1111 return true;
1112 folio = page_folio(page);
1113 return folio_test_hugetlb(folio) && PageHWPoison(&folio->page);
1114 }
1115
1116 bool is_free_buddy_page(const struct page *page);
1117
1118 PAGEFLAG(Isolated, isolated, PF_ANY);
1119
PageAnonExclusive(const struct page * page)1120 static __always_inline int PageAnonExclusive(const struct page *page)
1121 {
1122 VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
1123 /*
1124 * HugeTLB stores this information on the head page; THP keeps it per
1125 * page
1126 */
1127 if (PageHuge(page))
1128 page = compound_head(page);
1129 return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1130 }
1131
SetPageAnonExclusive(struct page * page)1132 static __always_inline void SetPageAnonExclusive(struct page *page)
1133 {
1134 VM_BUG_ON_PGFLAGS(!PageAnonNotKsm(page), page);
1135 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1136 set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1137 }
1138
ClearPageAnonExclusive(struct page * page)1139 static __always_inline void ClearPageAnonExclusive(struct page *page)
1140 {
1141 VM_BUG_ON_PGFLAGS(!PageAnonNotKsm(page), page);
1142 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1143 clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1144 }
1145
__ClearPageAnonExclusive(struct page * page)1146 static __always_inline void __ClearPageAnonExclusive(struct page *page)
1147 {
1148 VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
1149 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1150 __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1151 }
1152
1153 #ifdef CONFIG_MMU
1154 #define __PG_MLOCKED (1UL << PG_mlocked)
1155 #else
1156 #define __PG_MLOCKED 0
1157 #endif
1158
1159 /*
1160 * Flags checked when a page is freed. Pages being freed should not have
1161 * these flags set. If they are, there is a problem.
1162 */
1163 #define PAGE_FLAGS_CHECK_AT_FREE \
1164 (1UL << PG_lru | 1UL << PG_locked | \
1165 1UL << PG_private | 1UL << PG_private_2 | \
1166 1UL << PG_writeback | 1UL << PG_reserved | \
1167 1UL << PG_active | \
1168 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK)
1169
1170 /*
1171 * Flags checked when a page is prepped for return by the page allocator.
1172 * Pages being prepped should not have these flags set. If they are set,
1173 * there has been a kernel bug or struct page corruption.
1174 *
1175 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
1176 * alloc-free cycle to prevent from reusing the page.
1177 */
1178 #define PAGE_FLAGS_CHECK_AT_PREP \
1179 ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK)
1180
1181 /*
1182 * Flags stored in the second page of a compound page. They may overlap
1183 * the CHECK_AT_FREE flags above, so need to be cleared.
1184 */
1185 #define PAGE_FLAGS_SECOND \
1186 (0xffUL /* order */ | 1UL << PG_has_hwpoisoned | \
1187 1UL << PG_large_rmappable | 1UL << PG_partially_mapped)
1188
1189 #define PAGE_FLAGS_PRIVATE \
1190 (1UL << PG_private | 1UL << PG_private_2)
1191 /**
1192 * folio_has_private - Determine if folio has private stuff
1193 * @folio: The folio to be checked
1194 *
1195 * Determine if a folio has private stuff, indicating that release routines
1196 * should be invoked upon it.
1197 */
folio_has_private(const struct folio * folio)1198 static inline int folio_has_private(const struct folio *folio)
1199 {
1200 return !!(folio->flags & PAGE_FLAGS_PRIVATE);
1201 }
1202
1203 #undef PF_ANY
1204 #undef PF_HEAD
1205 #undef PF_NO_TAIL
1206 #undef PF_NO_COMPOUND
1207 #undef PF_SECOND
1208 #endif /* !__GENERATING_BOUNDS_H */
1209
1210 #endif /* PAGE_FLAGS_H */
1211