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 not added to the page allocator when onlining a section because |
34 | * they were excluded via the online_page_callback() or because they are |
35 | * PG_hwpoison. |
36 | * - Pages allocated in the context of kexec/kdump (loaded kernel image, |
37 | * control pages, vmcoreinfo) |
38 | * - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are |
39 | * not marked PG_reserved (as they might be in use by somebody else who does |
40 | * not respect the caching strategy). |
41 | * - Pages part of an offline section (struct pages of offline sections should |
42 | * not be trusted as they will be initialized when first onlined). |
43 | * - MCA pages on ia64 |
44 | * - Pages holding CPU notes for POWER Firmware Assisted Dump |
45 | * - Device memory (e.g. PMEM, DAX, HMM) |
46 | * Some PG_reserved pages will be excluded from the hibernation image. |
47 | * PG_reserved does in general not hinder anybody from dumping or swapping |
48 | * and is no longer required for remap_pfn_range(). ioremap might require it. |
49 | * Consequently, PG_reserved for a page mapped into user space can indicate |
50 | * the zero page, the vDSO, MMIO pages or device memory. |
51 | * |
52 | * The PG_private bitflag is set on pagecache pages if they contain filesystem |
53 | * specific data (which is normally at page->private). It can be used by |
54 | * private allocations for its own usage. |
55 | * |
56 | * During initiation of disk I/O, PG_locked is set. This bit is set before I/O |
57 | * and cleared when writeback _starts_ or when read _completes_. PG_writeback |
58 | * is set before writeback starts and cleared when it finishes. |
59 | * |
60 | * PG_locked also pins a page in pagecache, and blocks truncation of the file |
61 | * while it is held. |
62 | * |
63 | * page_waitqueue(page) is a wait queue of all tasks waiting for the page |
64 | * to become unlocked. |
65 | * |
66 | * PG_swapbacked is set when a page uses swap as a backing storage. This are |
67 | * usually PageAnon or shmem pages but please note that even anonymous pages |
68 | * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as |
69 | * a result of MADV_FREE). |
70 | * |
71 | * PG_referenced, PG_reclaim are used for page reclaim for anonymous and |
72 | * file-backed pagecache (see mm/vmscan.c). |
73 | * |
74 | * PG_error is set to indicate that an I/O error occurred on this page. |
75 | * |
76 | * PG_arch_1 is an architecture specific page state bit. The generic code |
77 | * guarantees that this bit is cleared for a page when it first is entered into |
78 | * the page cache. |
79 | * |
80 | * PG_hwpoison indicates that a page got corrupted in hardware and contains |
81 | * data with incorrect ECC bits that triggered a machine check. Accessing is |
82 | * not safe since it may cause another machine check. Don't touch! |
83 | */ |
84 | |
85 | /* |
86 | * Don't use the pageflags directly. Use the PageFoo macros. |
87 | * |
88 | * The page flags field is split into two parts, the main flags area |
89 | * which extends from the low bits upwards, and the fields area which |
90 | * extends from the high bits downwards. |
91 | * |
92 | * | FIELD | ... | FLAGS | |
93 | * N-1 ^ 0 |
94 | * (NR_PAGEFLAGS) |
95 | * |
96 | * The fields area is reserved for fields mapping zone, node (for NUMA) and |
97 | * SPARSEMEM section (for variants of SPARSEMEM that require section ids like |
98 | * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). |
99 | */ |
100 | enum pageflags { |
101 | PG_locked, /* Page is locked. Don't touch. */ |
102 | PG_writeback, /* Page is under writeback */ |
103 | PG_referenced, |
104 | PG_uptodate, |
105 | PG_dirty, |
106 | PG_lru, |
107 | PG_head, /* Must be in bit 6 */ |
108 | PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */ |
109 | PG_active, |
110 | PG_workingset, |
111 | PG_error, |
112 | PG_slab, |
113 | PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ |
114 | PG_arch_1, |
115 | PG_reserved, |
116 | PG_private, /* If pagecache, has fs-private data */ |
117 | PG_private_2, /* If pagecache, has fs aux data */ |
118 | PG_mappedtodisk, /* Has blocks allocated on-disk */ |
119 | PG_reclaim, /* To be reclaimed asap */ |
120 | PG_swapbacked, /* Page is backed by RAM/swap */ |
121 | PG_unevictable, /* Page is "unevictable" */ |
122 | #ifdef CONFIG_MMU |
123 | PG_mlocked, /* Page is vma mlocked */ |
124 | #endif |
125 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
126 | PG_uncached, /* Page has been mapped as uncached */ |
127 | #endif |
128 | #ifdef CONFIG_MEMORY_FAILURE |
129 | PG_hwpoison, /* hardware poisoned page. Don't touch */ |
130 | #endif |
131 | #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) |
132 | PG_young, |
133 | PG_idle, |
134 | #endif |
135 | #ifdef CONFIG_ARCH_USES_PG_ARCH_X |
136 | PG_arch_2, |
137 | PG_arch_3, |
138 | #endif |
139 | __NR_PAGEFLAGS, |
140 | |
141 | PG_readahead = PG_reclaim, |
142 | |
143 | /* |
144 | * Depending on the way an anonymous folio can be mapped into a page |
145 | * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped |
146 | * THP), PG_anon_exclusive may be set only for the head page or for |
147 | * tail pages of an anonymous folio. For now, we only expect it to be |
148 | * set on tail pages for PTE-mapped THP. |
149 | */ |
150 | PG_anon_exclusive = PG_mappedtodisk, |
151 | |
152 | /* Filesystems */ |
153 | PG_checked = PG_owner_priv_1, |
154 | |
155 | /* SwapBacked */ |
156 | PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */ |
157 | |
158 | /* Two page bits are conscripted by FS-Cache to maintain local caching |
159 | * state. These bits are set on pages belonging to the netfs's inodes |
160 | * when those inodes are being locally cached. |
161 | */ |
162 | PG_fscache = PG_private_2, /* page backed by cache */ |
163 | |
164 | /* XEN */ |
165 | /* Pinned in Xen as a read-only pagetable page. */ |
166 | PG_pinned = PG_owner_priv_1, |
167 | /* Pinned as part of domain save (see xen_mm_pin_all()). */ |
168 | PG_savepinned = PG_dirty, |
169 | /* Has a grant mapping of another (foreign) domain's page. */ |
170 | PG_foreign = PG_owner_priv_1, |
171 | /* Remapped by swiotlb-xen. */ |
172 | PG_xen_remapped = PG_owner_priv_1, |
173 | |
174 | /* non-lru isolated movable page */ |
175 | PG_isolated = PG_reclaim, |
176 | |
177 | /* Only valid for buddy pages. Used to track pages that are reported */ |
178 | PG_reported = PG_uptodate, |
179 | |
180 | #ifdef CONFIG_MEMORY_HOTPLUG |
181 | /* For self-hosted memmap pages */ |
182 | PG_vmemmap_self_hosted = PG_owner_priv_1, |
183 | #endif |
184 | |
185 | /* |
186 | * Flags only valid for compound pages. Stored in first tail page's |
187 | * flags word. Cannot use the first 8 flags or any flag marked as |
188 | * PF_ANY. |
189 | */ |
190 | |
191 | /* At least one page in this folio has the hwpoison flag set */ |
192 | PG_has_hwpoisoned = PG_error, |
193 | PG_hugetlb = PG_active, |
194 | PG_large_rmappable = PG_workingset, /* anon or file-backed */ |
195 | }; |
196 | |
197 | #define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1) |
198 | |
199 | #ifndef __GENERATING_BOUNDS_H |
200 | |
201 | #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP |
202 | DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key); |
203 | |
204 | /* |
205 | * Return the real head page struct iff the @page is a fake head page, otherwise |
206 | * return the @page itself. See Documentation/mm/vmemmap_dedup.rst. |
207 | */ |
208 | static __always_inline const struct page *page_fixed_fake_head(const struct page *page) |
209 | { |
210 | if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key)) |
211 | return page; |
212 | |
213 | /* |
214 | * Only addresses aligned with PAGE_SIZE of struct page may be fake head |
215 | * struct page. The alignment check aims to avoid access the fields ( |
216 | * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly) |
217 | * cold cacheline in some cases. |
218 | */ |
219 | if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) && |
220 | test_bit(PG_head, &page->flags)) { |
221 | /* |
222 | * We can safely access the field of the @page[1] with PG_head |
223 | * because the @page is a compound page composed with at least |
224 | * two contiguous pages. |
225 | */ |
226 | unsigned long head = READ_ONCE(page[1].compound_head); |
227 | |
228 | if (likely(head & 1)) |
229 | return (const struct page *)(head - 1); |
230 | } |
231 | return page; |
232 | } |
233 | #else |
234 | static inline const struct page *page_fixed_fake_head(const struct page *page) |
235 | { |
236 | return page; |
237 | } |
238 | #endif |
239 | |
240 | static __always_inline int page_is_fake_head(struct page *page) |
241 | { |
242 | return page_fixed_fake_head(page) != page; |
243 | } |
244 | |
245 | static inline unsigned long _compound_head(const struct page *page) |
246 | { |
247 | unsigned long head = READ_ONCE(page->compound_head); |
248 | |
249 | if (unlikely(head & 1)) |
250 | return head - 1; |
251 | return (unsigned long)page_fixed_fake_head(page); |
252 | } |
253 | |
254 | #define compound_head(page) ((typeof(page))_compound_head(page)) |
255 | |
256 | /** |
257 | * page_folio - Converts from page to folio. |
258 | * @p: The page. |
259 | * |
260 | * Every page is part of a folio. This function cannot be called on a |
261 | * NULL pointer. |
262 | * |
263 | * Context: No reference, nor lock is required on @page. If the caller |
264 | * does not hold a reference, this call may race with a folio split, so |
265 | * it should re-check the folio still contains this page after gaining |
266 | * a reference on the folio. |
267 | * Return: The folio which contains this page. |
268 | */ |
269 | #define page_folio(p) (_Generic((p), \ |
270 | const struct page *: (const struct folio *)_compound_head(p), \ |
271 | struct page *: (struct folio *)_compound_head(p))) |
272 | |
273 | /** |
274 | * folio_page - Return a page from a folio. |
275 | * @folio: The folio. |
276 | * @n: The page number to return. |
277 | * |
278 | * @n is relative to the start of the folio. This function does not |
279 | * check that the page number lies within @folio; the caller is presumed |
280 | * to have a reference to the page. |
281 | */ |
282 | #define folio_page(folio, n) nth_page(&(folio)->page, n) |
283 | |
284 | static __always_inline int PageTail(struct page *page) |
285 | { |
286 | return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page); |
287 | } |
288 | |
289 | static __always_inline int PageCompound(struct page *page) |
290 | { |
291 | return test_bit(PG_head, &page->flags) || |
292 | READ_ONCE(page->compound_head) & 1; |
293 | } |
294 | |
295 | #define PAGE_POISON_PATTERN -1l |
296 | static inline int PagePoisoned(const struct page *page) |
297 | { |
298 | return READ_ONCE(page->flags) == PAGE_POISON_PATTERN; |
299 | } |
300 | |
301 | #ifdef CONFIG_DEBUG_VM |
302 | void page_init_poison(struct page *page, size_t size); |
303 | #else |
304 | static inline void page_init_poison(struct page *page, size_t size) |
305 | { |
306 | } |
307 | #endif |
308 | |
309 | static unsigned long *folio_flags(struct folio *folio, unsigned n) |
310 | { |
311 | struct page *page = &folio->page; |
312 | |
313 | VM_BUG_ON_PGFLAGS(PageTail(page), page); |
314 | VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page); |
315 | return &page[n].flags; |
316 | } |
317 | |
318 | /* |
319 | * Page flags policies wrt compound pages |
320 | * |
321 | * PF_POISONED_CHECK |
322 | * check if this struct page poisoned/uninitialized |
323 | * |
324 | * PF_ANY: |
325 | * the page flag is relevant for small, head and tail pages. |
326 | * |
327 | * PF_HEAD: |
328 | * for compound page all operations related to the page flag applied to |
329 | * head page. |
330 | * |
331 | * PF_ONLY_HEAD: |
332 | * for compound page, callers only ever operate on the head page. |
333 | * |
334 | * PF_NO_TAIL: |
335 | * modifications of the page flag must be done on small or head pages, |
336 | * checks can be done on tail pages too. |
337 | * |
338 | * PF_NO_COMPOUND: |
339 | * the page flag is not relevant for compound pages. |
340 | * |
341 | * PF_SECOND: |
342 | * the page flag is stored in the first tail page. |
343 | */ |
344 | #define PF_POISONED_CHECK(page) ({ \ |
345 | VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \ |
346 | page; }) |
347 | #define PF_ANY(page, enforce) PF_POISONED_CHECK(page) |
348 | #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page)) |
349 | #define PF_ONLY_HEAD(page, enforce) ({ \ |
350 | VM_BUG_ON_PGFLAGS(PageTail(page), page); \ |
351 | PF_POISONED_CHECK(page); }) |
352 | #define PF_NO_TAIL(page, enforce) ({ \ |
353 | VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \ |
354 | PF_POISONED_CHECK(compound_head(page)); }) |
355 | #define PF_NO_COMPOUND(page, enforce) ({ \ |
356 | VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \ |
357 | PF_POISONED_CHECK(page); }) |
358 | #define PF_SECOND(page, enforce) ({ \ |
359 | VM_BUG_ON_PGFLAGS(!PageHead(page), page); \ |
360 | PF_POISONED_CHECK(&page[1]); }) |
361 | |
362 | /* Which page is the flag stored in */ |
363 | #define FOLIO_PF_ANY 0 |
364 | #define FOLIO_PF_HEAD 0 |
365 | #define FOLIO_PF_ONLY_HEAD 0 |
366 | #define FOLIO_PF_NO_TAIL 0 |
367 | #define FOLIO_PF_NO_COMPOUND 0 |
368 | #define FOLIO_PF_SECOND 1 |
369 | |
370 | /* |
371 | * Macros to create function definitions for page flags |
372 | */ |
373 | #define TESTPAGEFLAG(uname, lname, policy) \ |
374 | static __always_inline bool folio_test_##lname(struct folio *folio) \ |
375 | { return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ |
376 | static __always_inline int Page##uname(struct page *page) \ |
377 | { return test_bit(PG_##lname, &policy(page, 0)->flags); } |
378 | |
379 | #define SETPAGEFLAG(uname, lname, policy) \ |
380 | static __always_inline \ |
381 | void folio_set_##lname(struct folio *folio) \ |
382 | { set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ |
383 | static __always_inline void SetPage##uname(struct page *page) \ |
384 | { set_bit(PG_##lname, &policy(page, 1)->flags); } |
385 | |
386 | #define CLEARPAGEFLAG(uname, lname, policy) \ |
387 | static __always_inline \ |
388 | void folio_clear_##lname(struct folio *folio) \ |
389 | { clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ |
390 | static __always_inline void ClearPage##uname(struct page *page) \ |
391 | { clear_bit(PG_##lname, &policy(page, 1)->flags); } |
392 | |
393 | #define __SETPAGEFLAG(uname, lname, policy) \ |
394 | static __always_inline \ |
395 | void __folio_set_##lname(struct folio *folio) \ |
396 | { __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ |
397 | static __always_inline void __SetPage##uname(struct page *page) \ |
398 | { __set_bit(PG_##lname, &policy(page, 1)->flags); } |
399 | |
400 | #define __CLEARPAGEFLAG(uname, lname, policy) \ |
401 | static __always_inline \ |
402 | void __folio_clear_##lname(struct folio *folio) \ |
403 | { __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ |
404 | static __always_inline void __ClearPage##uname(struct page *page) \ |
405 | { __clear_bit(PG_##lname, &policy(page, 1)->flags); } |
406 | |
407 | #define TESTSETFLAG(uname, lname, policy) \ |
408 | static __always_inline \ |
409 | bool folio_test_set_##lname(struct folio *folio) \ |
410 | { return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ |
411 | static __always_inline int TestSetPage##uname(struct page *page) \ |
412 | { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } |
413 | |
414 | #define TESTCLEARFLAG(uname, lname, policy) \ |
415 | static __always_inline \ |
416 | bool folio_test_clear_##lname(struct folio *folio) \ |
417 | { return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ |
418 | static __always_inline int TestClearPage##uname(struct page *page) \ |
419 | { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } |
420 | |
421 | #define PAGEFLAG(uname, lname, policy) \ |
422 | TESTPAGEFLAG(uname, lname, policy) \ |
423 | SETPAGEFLAG(uname, lname, policy) \ |
424 | CLEARPAGEFLAG(uname, lname, policy) |
425 | |
426 | #define __PAGEFLAG(uname, lname, policy) \ |
427 | TESTPAGEFLAG(uname, lname, policy) \ |
428 | __SETPAGEFLAG(uname, lname, policy) \ |
429 | __CLEARPAGEFLAG(uname, lname, policy) |
430 | |
431 | #define TESTSCFLAG(uname, lname, policy) \ |
432 | TESTSETFLAG(uname, lname, policy) \ |
433 | TESTCLEARFLAG(uname, lname, policy) |
434 | |
435 | #define TESTPAGEFLAG_FALSE(uname, lname) \ |
436 | static inline bool folio_test_##lname(const struct folio *folio) { return false; } \ |
437 | static inline int Page##uname(const struct page *page) { return 0; } |
438 | |
439 | #define SETPAGEFLAG_NOOP(uname, lname) \ |
440 | static inline void folio_set_##lname(struct folio *folio) { } \ |
441 | static inline void SetPage##uname(struct page *page) { } |
442 | |
443 | #define CLEARPAGEFLAG_NOOP(uname, lname) \ |
444 | static inline void folio_clear_##lname(struct folio *folio) { } \ |
445 | static inline void ClearPage##uname(struct page *page) { } |
446 | |
447 | #define __CLEARPAGEFLAG_NOOP(uname, lname) \ |
448 | static inline void __folio_clear_##lname(struct folio *folio) { } \ |
449 | static inline void __ClearPage##uname(struct page *page) { } |
450 | |
451 | #define TESTSETFLAG_FALSE(uname, lname) \ |
452 | static inline bool folio_test_set_##lname(struct folio *folio) \ |
453 | { return 0; } \ |
454 | static inline int TestSetPage##uname(struct page *page) { return 0; } |
455 | |
456 | #define TESTCLEARFLAG_FALSE(uname, lname) \ |
457 | static inline bool folio_test_clear_##lname(struct folio *folio) \ |
458 | { return 0; } \ |
459 | static inline int TestClearPage##uname(struct page *page) { return 0; } |
460 | |
461 | #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \ |
462 | SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname) |
463 | |
464 | #define TESTSCFLAG_FALSE(uname, lname) \ |
465 | TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname) |
466 | |
467 | __PAGEFLAG(Locked, locked, PF_NO_TAIL) |
468 | PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) |
469 | PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL) |
470 | PAGEFLAG(Referenced, referenced, PF_HEAD) |
471 | TESTCLEARFLAG(Referenced, referenced, PF_HEAD) |
472 | __SETPAGEFLAG(Referenced, referenced, PF_HEAD) |
473 | PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) |
474 | __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) |
475 | PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) |
476 | TESTCLEARFLAG(LRU, lru, PF_HEAD) |
477 | PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) |
478 | TESTCLEARFLAG(Active, active, PF_HEAD) |
479 | PAGEFLAG(Workingset, workingset, PF_HEAD) |
480 | TESTCLEARFLAG(Workingset, workingset, PF_HEAD) |
481 | __PAGEFLAG(Slab, slab, PF_NO_TAIL) |
482 | PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */ |
483 | |
484 | /* Xen */ |
485 | PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) |
486 | TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) |
487 | PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND); |
488 | PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND); |
489 | PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) |
490 | TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) |
491 | |
492 | PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) |
493 | __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) |
494 | __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) |
495 | PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) |
496 | __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) |
497 | __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) |
498 | |
499 | /* |
500 | * Private page markings that may be used by the filesystem that owns the page |
501 | * for its own purposes. |
502 | * - PG_private and PG_private_2 cause release_folio() and co to be invoked |
503 | */ |
504 | PAGEFLAG(Private, private, PF_ANY) |
505 | PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY) |
506 | PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY) |
507 | TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY) |
508 | |
509 | /* |
510 | * Only test-and-set exist for PG_writeback. The unconditional operators are |
511 | * risky: they bypass page accounting. |
512 | */ |
513 | TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL) |
514 | TESTSCFLAG(Writeback, writeback, PF_NO_TAIL) |
515 | PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL) |
516 | |
517 | /* PG_readahead is only used for reads; PG_reclaim is only for writes */ |
518 | PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) |
519 | TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) |
520 | PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND) |
521 | TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND) |
522 | |
523 | #ifdef CONFIG_HIGHMEM |
524 | /* |
525 | * Must use a macro here due to header dependency issues. page_zone() is not |
526 | * available at this point. |
527 | */ |
528 | #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p)) |
529 | #define folio_test_highmem(__f) is_highmem_idx(folio_zonenum(__f)) |
530 | #else |
531 | PAGEFLAG_FALSE(HighMem, highmem) |
532 | #endif |
533 | |
534 | #ifdef CONFIG_SWAP |
535 | static __always_inline bool folio_test_swapcache(struct folio *folio) |
536 | { |
537 | return folio_test_swapbacked(folio) && |
538 | test_bit(PG_swapcache, folio_flags(folio, 0)); |
539 | } |
540 | |
541 | static __always_inline bool PageSwapCache(struct page *page) |
542 | { |
543 | return folio_test_swapcache(page_folio(page)); |
544 | } |
545 | |
546 | SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) |
547 | CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) |
548 | #else |
549 | PAGEFLAG_FALSE(SwapCache, swapcache) |
550 | #endif |
551 | |
552 | PAGEFLAG(Unevictable, unevictable, PF_HEAD) |
553 | __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD) |
554 | TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD) |
555 | |
556 | #ifdef CONFIG_MMU |
557 | PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) |
558 | __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) |
559 | TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL) |
560 | #else |
561 | PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked) |
562 | TESTSCFLAG_FALSE(Mlocked, mlocked) |
563 | #endif |
564 | |
565 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
566 | PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) |
567 | #else |
568 | PAGEFLAG_FALSE(Uncached, uncached) |
569 | #endif |
570 | |
571 | #ifdef CONFIG_MEMORY_FAILURE |
572 | PAGEFLAG(HWPoison, hwpoison, PF_ANY) |
573 | TESTSCFLAG(HWPoison, hwpoison, PF_ANY) |
574 | #define __PG_HWPOISON (1UL << PG_hwpoison) |
575 | #define MAGIC_HWPOISON 0x48575053U /* HWPS */ |
576 | extern void SetPageHWPoisonTakenOff(struct page *page); |
577 | extern void ClearPageHWPoisonTakenOff(struct page *page); |
578 | extern bool take_page_off_buddy(struct page *page); |
579 | extern bool put_page_back_buddy(struct page *page); |
580 | #else |
581 | PAGEFLAG_FALSE(HWPoison, hwpoison) |
582 | #define __PG_HWPOISON 0 |
583 | #endif |
584 | |
585 | #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) |
586 | TESTPAGEFLAG(Young, young, PF_ANY) |
587 | SETPAGEFLAG(Young, young, PF_ANY) |
588 | TESTCLEARFLAG(Young, young, PF_ANY) |
589 | PAGEFLAG(Idle, idle, PF_ANY) |
590 | #endif |
591 | |
592 | /* |
593 | * PageReported() is used to track reported free pages within the Buddy |
594 | * allocator. We can use the non-atomic version of the test and set |
595 | * operations as both should be shielded with the zone lock to prevent |
596 | * any possible races on the setting or clearing of the bit. |
597 | */ |
598 | __PAGEFLAG(Reported, reported, PF_NO_COMPOUND) |
599 | |
600 | #ifdef CONFIG_MEMORY_HOTPLUG |
601 | PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY) |
602 | #else |
603 | PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) |
604 | #endif |
605 | |
606 | /* |
607 | * On an anonymous page mapped into a user virtual memory area, |
608 | * page->mapping points to its anon_vma, not to a struct address_space; |
609 | * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. |
610 | * |
611 | * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, |
612 | * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON |
613 | * bit; and then page->mapping points, not to an anon_vma, but to a private |
614 | * structure which KSM associates with that merged page. See ksm.h. |
615 | * |
616 | * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable |
617 | * page and then page->mapping points to a struct movable_operations. |
618 | * |
619 | * Please note that, confusingly, "page_mapping" refers to the inode |
620 | * address_space which maps the page from disk; whereas "page_mapped" |
621 | * refers to user virtual address space into which the page is mapped. |
622 | * |
623 | * For slab pages, since slab reuses the bits in struct page to store its |
624 | * internal states, the page->mapping does not exist as such, nor do these |
625 | * flags below. So in order to avoid testing non-existent bits, please |
626 | * make sure that PageSlab(page) actually evaluates to false before calling |
627 | * the following functions (e.g., PageAnon). See mm/slab.h. |
628 | */ |
629 | #define PAGE_MAPPING_ANON 0x1 |
630 | #define PAGE_MAPPING_MOVABLE 0x2 |
631 | #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) |
632 | #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) |
633 | |
634 | /* |
635 | * Different with flags above, this flag is used only for fsdax mode. It |
636 | * indicates that this page->mapping is now under reflink case. |
637 | */ |
638 | #define PAGE_MAPPING_DAX_SHARED ((void *)0x1) |
639 | |
640 | static __always_inline bool folio_mapping_flags(struct folio *folio) |
641 | { |
642 | return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0; |
643 | } |
644 | |
645 | static __always_inline int PageMappingFlags(struct page *page) |
646 | { |
647 | return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; |
648 | } |
649 | |
650 | static __always_inline bool folio_test_anon(struct folio *folio) |
651 | { |
652 | return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0; |
653 | } |
654 | |
655 | static __always_inline bool PageAnon(struct page *page) |
656 | { |
657 | return folio_test_anon(page_folio(page)); |
658 | } |
659 | |
660 | static __always_inline bool __folio_test_movable(const struct folio *folio) |
661 | { |
662 | return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == |
663 | PAGE_MAPPING_MOVABLE; |
664 | } |
665 | |
666 | static __always_inline int __PageMovable(struct page *page) |
667 | { |
668 | return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == |
669 | PAGE_MAPPING_MOVABLE; |
670 | } |
671 | |
672 | #ifdef CONFIG_KSM |
673 | /* |
674 | * A KSM page is one of those write-protected "shared pages" or "merged pages" |
675 | * which KSM maps into multiple mms, wherever identical anonymous page content |
676 | * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any |
677 | * anon_vma, but to that page's node of the stable tree. |
678 | */ |
679 | static __always_inline bool folio_test_ksm(struct folio *folio) |
680 | { |
681 | return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == |
682 | PAGE_MAPPING_KSM; |
683 | } |
684 | |
685 | static __always_inline bool PageKsm(struct page *page) |
686 | { |
687 | return folio_test_ksm(page_folio(page)); |
688 | } |
689 | #else |
690 | TESTPAGEFLAG_FALSE(Ksm, ksm) |
691 | #endif |
692 | |
693 | u64 stable_page_flags(struct page *page); |
694 | |
695 | /** |
696 | * folio_xor_flags_has_waiters - Change some folio flags. |
697 | * @folio: The folio. |
698 | * @mask: Bits set in this word will be changed. |
699 | * |
700 | * This must only be used for flags which are changed with the folio |
701 | * lock held. For example, it is unsafe to use for PG_dirty as that |
702 | * can be set without the folio lock held. It can also only be used |
703 | * on flags which are in the range 0-6 as some of the implementations |
704 | * only affect those bits. |
705 | * |
706 | * Return: Whether there are tasks waiting on the folio. |
707 | */ |
708 | static inline bool folio_xor_flags_has_waiters(struct folio *folio, |
709 | unsigned long mask) |
710 | { |
711 | return xor_unlock_is_negative_byte(mask, addr: folio_flags(folio, n: 0)); |
712 | } |
713 | |
714 | /** |
715 | * folio_test_uptodate - Is this folio up to date? |
716 | * @folio: The folio. |
717 | * |
718 | * The uptodate flag is set on a folio when every byte in the folio is |
719 | * at least as new as the corresponding bytes on storage. Anonymous |
720 | * and CoW folios are always uptodate. If the folio is not uptodate, |
721 | * some of the bytes in it may be; see the is_partially_uptodate() |
722 | * address_space operation. |
723 | */ |
724 | static inline bool folio_test_uptodate(struct folio *folio) |
725 | { |
726 | bool ret = test_bit(PG_uptodate, folio_flags(folio, 0)); |
727 | /* |
728 | * Must ensure that the data we read out of the folio is loaded |
729 | * _after_ we've loaded folio->flags to check the uptodate bit. |
730 | * We can skip the barrier if the folio is not uptodate, because |
731 | * we wouldn't be reading anything from it. |
732 | * |
733 | * See folio_mark_uptodate() for the other side of the story. |
734 | */ |
735 | if (ret) |
736 | smp_rmb(); |
737 | |
738 | return ret; |
739 | } |
740 | |
741 | static inline int PageUptodate(struct page *page) |
742 | { |
743 | return folio_test_uptodate(page_folio(page)); |
744 | } |
745 | |
746 | static __always_inline void __folio_mark_uptodate(struct folio *folio) |
747 | { |
748 | smp_wmb(); |
749 | __set_bit(PG_uptodate, folio_flags(folio, 0)); |
750 | } |
751 | |
752 | static __always_inline void folio_mark_uptodate(struct folio *folio) |
753 | { |
754 | /* |
755 | * Memory barrier must be issued before setting the PG_uptodate bit, |
756 | * so that all previous stores issued in order to bring the folio |
757 | * uptodate are actually visible before folio_test_uptodate becomes true. |
758 | */ |
759 | smp_wmb(); |
760 | set_bit(nr: PG_uptodate, addr: folio_flags(folio, n: 0)); |
761 | } |
762 | |
763 | static __always_inline void __SetPageUptodate(struct page *page) |
764 | { |
765 | __folio_mark_uptodate(folio: (struct folio *)page); |
766 | } |
767 | |
768 | static __always_inline void SetPageUptodate(struct page *page) |
769 | { |
770 | folio_mark_uptodate(folio: (struct folio *)page); |
771 | } |
772 | |
773 | CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) |
774 | |
775 | bool __folio_start_writeback(struct folio *folio, bool keep_write); |
776 | bool set_page_writeback(struct page *page); |
777 | |
778 | #define folio_start_writeback(folio) \ |
779 | __folio_start_writeback(folio, false) |
780 | #define folio_start_writeback_keepwrite(folio) \ |
781 | __folio_start_writeback(folio, true) |
782 | |
783 | static inline bool test_set_page_writeback(struct page *page) |
784 | { |
785 | return set_page_writeback(page); |
786 | } |
787 | |
788 | static __always_inline bool folio_test_head(struct folio *folio) |
789 | { |
790 | return test_bit(PG_head, folio_flags(folio, FOLIO_PF_ANY)); |
791 | } |
792 | |
793 | static __always_inline int PageHead(struct page *page) |
794 | { |
795 | PF_POISONED_CHECK(page); |
796 | return test_bit(PG_head, &page->flags) && !page_is_fake_head(page); |
797 | } |
798 | |
799 | __SETPAGEFLAG(Head, head, PF_ANY) |
800 | __CLEARPAGEFLAG(Head, head, PF_ANY) |
801 | CLEARPAGEFLAG(Head, head, PF_ANY) |
802 | |
803 | /** |
804 | * folio_test_large() - Does this folio contain more than one page? |
805 | * @folio: The folio to test. |
806 | * |
807 | * Return: True if the folio is larger than one page. |
808 | */ |
809 | static inline bool folio_test_large(struct folio *folio) |
810 | { |
811 | return folio_test_head(folio); |
812 | } |
813 | |
814 | static __always_inline void set_compound_head(struct page *page, struct page *head) |
815 | { |
816 | WRITE_ONCE(page->compound_head, (unsigned long)head + 1); |
817 | } |
818 | |
819 | static __always_inline void clear_compound_head(struct page *page) |
820 | { |
821 | WRITE_ONCE(page->compound_head, 0); |
822 | } |
823 | |
824 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
825 | static inline void ClearPageCompound(struct page *page) |
826 | { |
827 | BUG_ON(!PageHead(page)); |
828 | ClearPageHead(page); |
829 | } |
830 | PAGEFLAG(LargeRmappable, large_rmappable, PF_SECOND) |
831 | #else |
832 | TESTPAGEFLAG_FALSE(LargeRmappable, large_rmappable) |
833 | #endif |
834 | |
835 | #define PG_head_mask ((1UL << PG_head)) |
836 | |
837 | #ifdef CONFIG_HUGETLB_PAGE |
838 | int PageHuge(struct page *page); |
839 | SETPAGEFLAG(HugeTLB, hugetlb, PF_SECOND) |
840 | CLEARPAGEFLAG(HugeTLB, hugetlb, PF_SECOND) |
841 | |
842 | /** |
843 | * folio_test_hugetlb - Determine if the folio belongs to hugetlbfs |
844 | * @folio: The folio to test. |
845 | * |
846 | * Context: Any context. Caller should have a reference on the folio to |
847 | * prevent it from being turned into a tail page. |
848 | * Return: True for hugetlbfs folios, false for anon folios or folios |
849 | * belonging to other filesystems. |
850 | */ |
851 | static inline bool folio_test_hugetlb(struct folio *folio) |
852 | { |
853 | return folio_test_large(folio) && |
854 | test_bit(PG_hugetlb, folio_flags(folio, 1)); |
855 | } |
856 | #else |
857 | TESTPAGEFLAG_FALSE(Huge, hugetlb) |
858 | #endif |
859 | |
860 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
861 | /* |
862 | * PageHuge() only returns true for hugetlbfs pages, but not for |
863 | * normal or transparent huge pages. |
864 | * |
865 | * PageTransHuge() returns true for both transparent huge and |
866 | * hugetlbfs pages, but not normal pages. PageTransHuge() can only be |
867 | * called only in the core VM paths where hugetlbfs pages can't exist. |
868 | */ |
869 | static inline int PageTransHuge(struct page *page) |
870 | { |
871 | VM_BUG_ON_PAGE(PageTail(page), page); |
872 | return PageHead(page); |
873 | } |
874 | |
875 | /* |
876 | * PageTransCompound returns true for both transparent huge pages |
877 | * and hugetlbfs pages, so it should only be called when it's known |
878 | * that hugetlbfs pages aren't involved. |
879 | */ |
880 | static inline int PageTransCompound(struct page *page) |
881 | { |
882 | return PageCompound(page); |
883 | } |
884 | |
885 | /* |
886 | * PageTransTail returns true for both transparent huge pages |
887 | * and hugetlbfs pages, so it should only be called when it's known |
888 | * that hugetlbfs pages aren't involved. |
889 | */ |
890 | static inline int PageTransTail(struct page *page) |
891 | { |
892 | return PageTail(page); |
893 | } |
894 | #else |
895 | TESTPAGEFLAG_FALSE(TransHuge, transhuge) |
896 | TESTPAGEFLAG_FALSE(TransCompound, transcompound) |
897 | TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap) |
898 | TESTPAGEFLAG_FALSE(TransTail, transtail) |
899 | #endif |
900 | |
901 | #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE) |
902 | /* |
903 | * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the |
904 | * compound page. |
905 | * |
906 | * This flag is set by hwpoison handler. Cleared by THP split or free page. |
907 | */ |
908 | PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) |
909 | TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) |
910 | #else |
911 | PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) |
912 | TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) |
913 | #endif |
914 | |
915 | /* |
916 | * Check if a page is currently marked HWPoisoned. Note that this check is |
917 | * best effort only and inherently racy: there is no way to synchronize with |
918 | * failing hardware. |
919 | */ |
920 | static inline bool is_page_hwpoison(struct page *page) |
921 | { |
922 | if (PageHWPoison(page)) |
923 | return true; |
924 | return PageHuge(page) && PageHWPoison(compound_head(page)); |
925 | } |
926 | |
927 | /* |
928 | * For pages that are never mapped to userspace (and aren't PageSlab), |
929 | * page_type may be used. Because it is initialised to -1, we invert the |
930 | * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and |
931 | * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and |
932 | * low bits so that an underflow or overflow of page_mapcount() won't be |
933 | * mistaken for a page type value. |
934 | */ |
935 | |
936 | #define PAGE_TYPE_BASE 0xf0000000 |
937 | /* Reserve 0x0000007f to catch underflows of page_mapcount */ |
938 | #define PAGE_MAPCOUNT_RESERVE -128 |
939 | #define PG_buddy 0x00000080 |
940 | #define PG_offline 0x00000100 |
941 | #define PG_table 0x00000200 |
942 | #define PG_guard 0x00000400 |
943 | |
944 | #define PageType(page, flag) \ |
945 | ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) |
946 | #define folio_test_type(folio, flag) \ |
947 | ((folio->page.page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) |
948 | |
949 | static inline int page_type_has_type(unsigned int page_type) |
950 | { |
951 | return (int)page_type < PAGE_MAPCOUNT_RESERVE; |
952 | } |
953 | |
954 | static inline int page_has_type(struct page *page) |
955 | { |
956 | return page_type_has_type(page_type: page->page_type); |
957 | } |
958 | |
959 | #define PAGE_TYPE_OPS(uname, lname, fname) \ |
960 | static __always_inline int Page##uname(const struct page *page) \ |
961 | { \ |
962 | return PageType(page, PG_##lname); \ |
963 | } \ |
964 | static __always_inline int folio_test_##fname(const struct folio *folio)\ |
965 | { \ |
966 | return folio_test_type(folio, PG_##lname); \ |
967 | } \ |
968 | static __always_inline void __SetPage##uname(struct page *page) \ |
969 | { \ |
970 | VM_BUG_ON_PAGE(!PageType(page, 0), page); \ |
971 | page->page_type &= ~PG_##lname; \ |
972 | } \ |
973 | static __always_inline void __folio_set_##fname(struct folio *folio) \ |
974 | { \ |
975 | VM_BUG_ON_FOLIO(!folio_test_type(folio, 0), folio); \ |
976 | folio->page.page_type &= ~PG_##lname; \ |
977 | } \ |
978 | static __always_inline void __ClearPage##uname(struct page *page) \ |
979 | { \ |
980 | VM_BUG_ON_PAGE(!Page##uname(page), page); \ |
981 | page->page_type |= PG_##lname; \ |
982 | } \ |
983 | static __always_inline void __folio_clear_##fname(struct folio *folio) \ |
984 | { \ |
985 | VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio); \ |
986 | folio->page.page_type |= PG_##lname; \ |
987 | } \ |
988 | |
989 | /* |
990 | * PageBuddy() indicates that the page is free and in the buddy system |
991 | * (see mm/page_alloc.c). |
992 | */ |
993 | PAGE_TYPE_OPS(Buddy, buddy, buddy) |
994 | |
995 | /* |
996 | * PageOffline() indicates that the page is logically offline although the |
997 | * containing section is online. (e.g. inflated in a balloon driver or |
998 | * not onlined when onlining the section). |
999 | * The content of these pages is effectively stale. Such pages should not |
1000 | * be touched (read/write/dump/save) except by their owner. |
1001 | * |
1002 | * If a driver wants to allow to offline unmovable PageOffline() pages without |
1003 | * putting them back to the buddy, it can do so via the memory notifier by |
1004 | * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the |
1005 | * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline() |
1006 | * pages (now with a reference count of zero) are treated like free pages, |
1007 | * allowing the containing memory block to get offlined. A driver that |
1008 | * relies on this feature is aware that re-onlining the memory block will |
1009 | * require to re-set the pages PageOffline() and not giving them to the |
1010 | * buddy via online_page_callback_t. |
1011 | * |
1012 | * There are drivers that mark a page PageOffline() and expect there won't be |
1013 | * any further access to page content. PFN walkers that read content of random |
1014 | * pages should check PageOffline() and synchronize with such drivers using |
1015 | * page_offline_freeze()/page_offline_thaw(). |
1016 | */ |
1017 | PAGE_TYPE_OPS(Offline, offline, offline) |
1018 | |
1019 | extern void page_offline_freeze(void); |
1020 | extern void page_offline_thaw(void); |
1021 | extern void page_offline_begin(void); |
1022 | extern void page_offline_end(void); |
1023 | |
1024 | /* |
1025 | * Marks pages in use as page tables. |
1026 | */ |
1027 | PAGE_TYPE_OPS(Table, table, pgtable) |
1028 | |
1029 | /* |
1030 | * Marks guardpages used with debug_pagealloc. |
1031 | */ |
1032 | PAGE_TYPE_OPS(Guard, guard, guard) |
1033 | |
1034 | extern bool is_free_buddy_page(struct page *page); |
1035 | |
1036 | PAGEFLAG(Isolated, isolated, PF_ANY); |
1037 | |
1038 | static __always_inline int PageAnonExclusive(struct page *page) |
1039 | { |
1040 | VM_BUG_ON_PGFLAGS(!PageAnon(page), page); |
1041 | VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); |
1042 | return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); |
1043 | } |
1044 | |
1045 | static __always_inline void SetPageAnonExclusive(struct page *page) |
1046 | { |
1047 | VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); |
1048 | VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); |
1049 | set_bit(nr: PG_anon_exclusive, addr: &PF_ANY(page, 1)->flags); |
1050 | } |
1051 | |
1052 | static __always_inline void ClearPageAnonExclusive(struct page *page) |
1053 | { |
1054 | VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); |
1055 | VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); |
1056 | clear_bit(nr: PG_anon_exclusive, addr: &PF_ANY(page, 1)->flags); |
1057 | } |
1058 | |
1059 | static __always_inline void __ClearPageAnonExclusive(struct page *page) |
1060 | { |
1061 | VM_BUG_ON_PGFLAGS(!PageAnon(page), page); |
1062 | VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); |
1063 | __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); |
1064 | } |
1065 | |
1066 | #ifdef CONFIG_MMU |
1067 | #define __PG_MLOCKED (1UL << PG_mlocked) |
1068 | #else |
1069 | #define __PG_MLOCKED 0 |
1070 | #endif |
1071 | |
1072 | /* |
1073 | * Flags checked when a page is freed. Pages being freed should not have |
1074 | * these flags set. If they are, there is a problem. |
1075 | */ |
1076 | #define PAGE_FLAGS_CHECK_AT_FREE \ |
1077 | (1UL << PG_lru | 1UL << PG_locked | \ |
1078 | 1UL << PG_private | 1UL << PG_private_2 | \ |
1079 | 1UL << PG_writeback | 1UL << PG_reserved | \ |
1080 | 1UL << PG_slab | 1UL << PG_active | \ |
1081 | 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK) |
1082 | |
1083 | /* |
1084 | * Flags checked when a page is prepped for return by the page allocator. |
1085 | * Pages being prepped should not have these flags set. If they are set, |
1086 | * there has been a kernel bug or struct page corruption. |
1087 | * |
1088 | * __PG_HWPOISON is exceptional because it needs to be kept beyond page's |
1089 | * alloc-free cycle to prevent from reusing the page. |
1090 | */ |
1091 | #define PAGE_FLAGS_CHECK_AT_PREP \ |
1092 | ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK) |
1093 | |
1094 | /* |
1095 | * Flags stored in the second page of a compound page. They may overlap |
1096 | * the CHECK_AT_FREE flags above, so need to be cleared. |
1097 | */ |
1098 | #define PAGE_FLAGS_SECOND \ |
1099 | (0xffUL /* order */ | 1UL << PG_has_hwpoisoned | \ |
1100 | 1UL << PG_hugetlb | 1UL << PG_large_rmappable) |
1101 | |
1102 | #define PAGE_FLAGS_PRIVATE \ |
1103 | (1UL << PG_private | 1UL << PG_private_2) |
1104 | /** |
1105 | * page_has_private - Determine if page has private stuff |
1106 | * @page: The page to be checked |
1107 | * |
1108 | * Determine if a page has private stuff, indicating that release routines |
1109 | * should be invoked upon it. |
1110 | */ |
1111 | static inline int page_has_private(struct page *page) |
1112 | { |
1113 | return !!(page->flags & PAGE_FLAGS_PRIVATE); |
1114 | } |
1115 | |
1116 | static inline bool folio_has_private(struct folio *folio) |
1117 | { |
1118 | return page_has_private(page: &folio->page); |
1119 | } |
1120 | |
1121 | #undef PF_ANY |
1122 | #undef PF_HEAD |
1123 | #undef PF_ONLY_HEAD |
1124 | #undef PF_NO_TAIL |
1125 | #undef PF_NO_COMPOUND |
1126 | #undef PF_SECOND |
1127 | #endif /* !__GENERATING_BOUNDS_H */ |
1128 | |
1129 | #endif /* PAGE_FLAGS_H */ |
1130 | |