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_uptodate tells whether the page's contents is valid. When a read
67 * completes, the page becomes uptodate, unless a disk I/O error happened.
68 *
69 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
70 * file-backed pagecache (see mm/vmscan.c).
71 *
72 * PG_error is set to indicate that an I/O error occurred on this page.
73 *
74 * PG_arch_1 is an architecture specific page state bit. The generic code
75 * guarantees that this bit is cleared for a page when it first is entered into
76 * the page cache.
77 *
78 * PG_hwpoison indicates that a page got corrupted in hardware and contains
79 * data with incorrect ECC bits that triggered a machine check. Accessing is
80 * not safe since it may cause another machine check. Don't touch!
81 */
82
83 /*
84 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
85 * locked- and dirty-page accounting.
86 *
87 * The page flags field is split into two parts, the main flags area
88 * which extends from the low bits upwards, and the fields area which
89 * extends from the high bits downwards.
90 *
91 * | FIELD | ... | FLAGS |
92 * N-1 ^ 0
93 * (NR_PAGEFLAGS)
94 *
95 * The fields area is reserved for fields mapping zone, node (for NUMA) and
96 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
97 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
98 */
99 enum pageflags {
100 PG_locked, /* Page is locked. Don't touch. */
101 PG_referenced,
102 PG_uptodate,
103 PG_dirty,
104 PG_lru,
105 PG_active,
106 PG_workingset,
107 PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
108 PG_error,
109 PG_slab,
110 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
111 PG_arch_1,
112 PG_reserved,
113 PG_private, /* If pagecache, has fs-private data */
114 PG_private_2, /* If pagecache, has fs aux data */
115 PG_writeback, /* Page is under writeback */
116 PG_head, /* A head page */
117 PG_mappedtodisk, /* Has blocks allocated on-disk */
118 PG_reclaim, /* To be reclaimed asap */
119 PG_swapbacked, /* Page is backed by RAM/swap */
120 PG_unevictable, /* Page is "unevictable" */
121 #ifdef CONFIG_MMU
122 PG_mlocked, /* Page is vma mlocked */
123 #endif
124 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
125 PG_uncached, /* Page has been mapped as uncached */
126 #endif
127 #ifdef CONFIG_MEMORY_FAILURE
128 PG_hwpoison, /* hardware poisoned page. Don't touch */
129 #endif
130 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
131 PG_young,
132 PG_idle,
133 #endif
134 __NR_PAGEFLAGS,
135
136 /* Filesystems */
137 PG_checked = PG_owner_priv_1,
138
139 /* SwapBacked */
140 PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
141
142 /* Two page bits are conscripted by FS-Cache to maintain local caching
143 * state. These bits are set on pages belonging to the netfs's inodes
144 * when those inodes are being locally cached.
145 */
146 PG_fscache = PG_private_2, /* page backed by cache */
147
148 /* XEN */
149 /* Pinned in Xen as a read-only pagetable page. */
150 PG_pinned = PG_owner_priv_1,
151 /* Pinned as part of domain save (see xen_mm_pin_all()). */
152 PG_savepinned = PG_dirty,
153 /* Has a grant mapping of another (foreign) domain's page. */
154 PG_foreign = PG_owner_priv_1,
155 /* Remapped by swiotlb-xen. */
156 PG_xen_remapped = PG_owner_priv_1,
157
158 /* SLOB */
159 PG_slob_free = PG_private,
160
161 /* Compound pages. Stored in first tail page's flags */
162 PG_double_map = PG_private_2,
163
164 /* non-lru isolated movable page */
165 PG_isolated = PG_reclaim,
166 };
167
168 #ifndef __GENERATING_BOUNDS_H
169
170 struct page; /* forward declaration */
171
compound_head(struct page * page)172 static inline struct page *compound_head(struct page *page)
173 {
174 unsigned long head = READ_ONCE(page->compound_head);
175
176 if (unlikely(head & 1))
177 return (struct page *) (head - 1);
178 return page;
179 }
180
PageTail(struct page * page)181 static __always_inline int PageTail(struct page *page)
182 {
183 return READ_ONCE(page->compound_head) & 1;
184 }
185
PageCompound(struct page * page)186 static __always_inline int PageCompound(struct page *page)
187 {
188 return test_bit(PG_head, &page->flags) || PageTail(page);
189 }
190
191 #define PAGE_POISON_PATTERN -1l
PagePoisoned(const struct page * page)192 static inline int PagePoisoned(const struct page *page)
193 {
194 return page->flags == PAGE_POISON_PATTERN;
195 }
196
197 #ifdef CONFIG_DEBUG_VM
198 void page_init_poison(struct page *page, size_t size);
199 #else
page_init_poison(struct page * page,size_t size)200 static inline void page_init_poison(struct page *page, size_t size)
201 {
202 }
203 #endif
204
205 /*
206 * Page flags policies wrt compound pages
207 *
208 * PF_POISONED_CHECK
209 * check if this struct page poisoned/uninitialized
210 *
211 * PF_ANY:
212 * the page flag is relevant for small, head and tail pages.
213 *
214 * PF_HEAD:
215 * for compound page all operations related to the page flag applied to
216 * head page.
217 *
218 * PF_ONLY_HEAD:
219 * for compound page, callers only ever operate on the head page.
220 *
221 * PF_NO_TAIL:
222 * modifications of the page flag must be done on small or head pages,
223 * checks can be done on tail pages too.
224 *
225 * PF_NO_COMPOUND:
226 * the page flag is not relevant for compound pages.
227 */
228 #define PF_POISONED_CHECK(page) ({ \
229 VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
230 page; })
231 #define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
232 #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
233 #define PF_ONLY_HEAD(page, enforce) ({ \
234 VM_BUG_ON_PGFLAGS(PageTail(page), page); \
235 PF_POISONED_CHECK(page); })
236 #define PF_NO_TAIL(page, enforce) ({ \
237 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
238 PF_POISONED_CHECK(compound_head(page)); })
239 #define PF_NO_COMPOUND(page, enforce) ({ \
240 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
241 PF_POISONED_CHECK(page); })
242
243 /*
244 * Macros to create function definitions for page flags
245 */
246 #define TESTPAGEFLAG(uname, lname, policy) \
247 static __always_inline int Page##uname(struct page *page) \
248 { return test_bit(PG_##lname, &policy(page, 0)->flags); }
249
250 #define SETPAGEFLAG(uname, lname, policy) \
251 static __always_inline void SetPage##uname(struct page *page) \
252 { set_bit(PG_##lname, &policy(page, 1)->flags); }
253
254 #define CLEARPAGEFLAG(uname, lname, policy) \
255 static __always_inline void ClearPage##uname(struct page *page) \
256 { clear_bit(PG_##lname, &policy(page, 1)->flags); }
257
258 #define __SETPAGEFLAG(uname, lname, policy) \
259 static __always_inline void __SetPage##uname(struct page *page) \
260 { __set_bit(PG_##lname, &policy(page, 1)->flags); }
261
262 #define __CLEARPAGEFLAG(uname, lname, policy) \
263 static __always_inline void __ClearPage##uname(struct page *page) \
264 { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
265
266 #define TESTSETFLAG(uname, lname, policy) \
267 static __always_inline int TestSetPage##uname(struct page *page) \
268 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
269
270 #define TESTCLEARFLAG(uname, lname, policy) \
271 static __always_inline int TestClearPage##uname(struct page *page) \
272 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
273
274 #define PAGEFLAG(uname, lname, policy) \
275 TESTPAGEFLAG(uname, lname, policy) \
276 SETPAGEFLAG(uname, lname, policy) \
277 CLEARPAGEFLAG(uname, lname, policy)
278
279 #define __PAGEFLAG(uname, lname, policy) \
280 TESTPAGEFLAG(uname, lname, policy) \
281 __SETPAGEFLAG(uname, lname, policy) \
282 __CLEARPAGEFLAG(uname, lname, policy)
283
284 #define TESTSCFLAG(uname, lname, policy) \
285 TESTSETFLAG(uname, lname, policy) \
286 TESTCLEARFLAG(uname, lname, policy)
287
288 #define TESTPAGEFLAG_FALSE(uname) \
289 static inline int Page##uname(const struct page *page) { return 0; }
290
291 #define SETPAGEFLAG_NOOP(uname) \
292 static inline void SetPage##uname(struct page *page) { }
293
294 #define CLEARPAGEFLAG_NOOP(uname) \
295 static inline void ClearPage##uname(struct page *page) { }
296
297 #define __CLEARPAGEFLAG_NOOP(uname) \
298 static inline void __ClearPage##uname(struct page *page) { }
299
300 #define TESTSETFLAG_FALSE(uname) \
301 static inline int TestSetPage##uname(struct page *page) { return 0; }
302
303 #define TESTCLEARFLAG_FALSE(uname) \
304 static inline int TestClearPage##uname(struct page *page) { return 0; }
305
306 #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
307 SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
308
309 #define TESTSCFLAG_FALSE(uname) \
310 TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
311
312 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
313 PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
314 PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
315 PAGEFLAG(Referenced, referenced, PF_HEAD)
316 TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
317 __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
318 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
319 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
320 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
321 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
322 TESTCLEARFLAG(Active, active, PF_HEAD)
323 PAGEFLAG(Workingset, workingset, PF_HEAD)
324 TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
325 __PAGEFLAG(Slab, slab, PF_NO_TAIL)
326 __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
327 PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
328
329 /* Xen */
330 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
331 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
332 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
333 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
PAGEFLAG(XenRemapped,xen_remapped,PF_NO_COMPOUND)334 PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
335 TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
336
337 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
338 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
339 __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
340 PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
341 __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
342 __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
343
344 /*
345 * Private page markings that may be used by the filesystem that owns the page
346 * for its own purposes.
347 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
348 */
349 PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
350 __CLEARPAGEFLAG(Private, private, PF_ANY)
351 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
352 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
353 TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
354
355 /*
356 * Only test-and-set exist for PG_writeback. The unconditional operators are
357 * risky: they bypass page accounting.
358 */
359 TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
360 TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
361 PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
362
363 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
364 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
365 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
366 PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
367 TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
368
369 #ifdef CONFIG_HIGHMEM
370 /*
371 * Must use a macro here due to header dependency issues. page_zone() is not
372 * available at this point.
373 */
374 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
375 #else
376 PAGEFLAG_FALSE(HighMem)
377 #endif
378
379 #ifdef CONFIG_SWAP
380 static __always_inline int PageSwapCache(struct page *page)
381 {
382 #ifdef CONFIG_THP_SWAP
383 page = compound_head(page);
384 #endif
385 return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags);
386
387 }
388 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
389 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
390 #else
391 PAGEFLAG_FALSE(SwapCache)
392 #endif
393
394 PAGEFLAG(Unevictable, unevictable, PF_HEAD)
395 __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
396 TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
397
398 #ifdef CONFIG_MMU
399 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
400 __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
401 TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
402 #else
403 PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
404 TESTSCFLAG_FALSE(Mlocked)
405 #endif
406
407 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
408 PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
409 #else
410 PAGEFLAG_FALSE(Uncached)
411 #endif
412
413 #ifdef CONFIG_MEMORY_FAILURE
414 PAGEFLAG(HWPoison, hwpoison, PF_ANY)
415 TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
416 #define __PG_HWPOISON (1UL << PG_hwpoison)
417 extern bool set_hwpoison_free_buddy_page(struct page *page);
418 #else
419 PAGEFLAG_FALSE(HWPoison)
420 static inline bool set_hwpoison_free_buddy_page(struct page *page)
421 {
422 return 0;
423 }
424 #define __PG_HWPOISON 0
425 #endif
426
427 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
TESTPAGEFLAG(Young,young,PF_ANY)428 TESTPAGEFLAG(Young, young, PF_ANY)
429 SETPAGEFLAG(Young, young, PF_ANY)
430 TESTCLEARFLAG(Young, young, PF_ANY)
431 PAGEFLAG(Idle, idle, PF_ANY)
432 #endif
433
434 /*
435 * On an anonymous page mapped into a user virtual memory area,
436 * page->mapping points to its anon_vma, not to a struct address_space;
437 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
438 *
439 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
440 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
441 * bit; and then page->mapping points, not to an anon_vma, but to a private
442 * structure which KSM associates with that merged page. See ksm.h.
443 *
444 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
445 * page and then page->mapping points a struct address_space.
446 *
447 * Please note that, confusingly, "page_mapping" refers to the inode
448 * address_space which maps the page from disk; whereas "page_mapped"
449 * refers to user virtual address space into which the page is mapped.
450 */
451 #define PAGE_MAPPING_ANON 0x1
452 #define PAGE_MAPPING_MOVABLE 0x2
453 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
454 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
455
456 static __always_inline int PageMappingFlags(struct page *page)
457 {
458 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
459 }
460
PageAnon(struct page * page)461 static __always_inline int PageAnon(struct page *page)
462 {
463 page = compound_head(page);
464 return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
465 }
466
__PageMovable(struct page * page)467 static __always_inline int __PageMovable(struct page *page)
468 {
469 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
470 PAGE_MAPPING_MOVABLE;
471 }
472
473 #ifdef CONFIG_KSM
474 /*
475 * A KSM page is one of those write-protected "shared pages" or "merged pages"
476 * which KSM maps into multiple mms, wherever identical anonymous page content
477 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
478 * anon_vma, but to that page's node of the stable tree.
479 */
PageKsm(struct page * page)480 static __always_inline int PageKsm(struct page *page)
481 {
482 page = compound_head(page);
483 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
484 PAGE_MAPPING_KSM;
485 }
486 #else
487 TESTPAGEFLAG_FALSE(Ksm)
488 #endif
489
490 u64 stable_page_flags(struct page *page);
491
PageUptodate(struct page * page)492 static inline int PageUptodate(struct page *page)
493 {
494 int ret;
495 page = compound_head(page);
496 ret = test_bit(PG_uptodate, &(page)->flags);
497 /*
498 * Must ensure that the data we read out of the page is loaded
499 * _after_ we've loaded page->flags to check for PageUptodate.
500 * We can skip the barrier if the page is not uptodate, because
501 * we wouldn't be reading anything from it.
502 *
503 * See SetPageUptodate() for the other side of the story.
504 */
505 if (ret)
506 smp_rmb();
507
508 return ret;
509 }
510
__SetPageUptodate(struct page * page)511 static __always_inline void __SetPageUptodate(struct page *page)
512 {
513 VM_BUG_ON_PAGE(PageTail(page), page);
514 smp_wmb();
515 __set_bit(PG_uptodate, &page->flags);
516 }
517
SetPageUptodate(struct page * page)518 static __always_inline void SetPageUptodate(struct page *page)
519 {
520 VM_BUG_ON_PAGE(PageTail(page), page);
521 /*
522 * Memory barrier must be issued before setting the PG_uptodate bit,
523 * so that all previous stores issued in order to bring the page
524 * uptodate are actually visible before PageUptodate becomes true.
525 */
526 smp_wmb();
527 set_bit(PG_uptodate, &page->flags);
528 }
529
530 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
531
532 int test_clear_page_writeback(struct page *page);
533 int __test_set_page_writeback(struct page *page, bool keep_write);
534
535 #define test_set_page_writeback(page) \
536 __test_set_page_writeback(page, false)
537 #define test_set_page_writeback_keepwrite(page) \
538 __test_set_page_writeback(page, true)
539
set_page_writeback(struct page * page)540 static inline void set_page_writeback(struct page *page)
541 {
542 test_set_page_writeback(page);
543 }
544
set_page_writeback_keepwrite(struct page * page)545 static inline void set_page_writeback_keepwrite(struct page *page)
546 {
547 test_set_page_writeback_keepwrite(page);
548 }
549
__PAGEFLAG(Head,head,PF_ANY)550 __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
551
552 static __always_inline void set_compound_head(struct page *page, struct page *head)
553 {
554 WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
555 }
556
clear_compound_head(struct page * page)557 static __always_inline void clear_compound_head(struct page *page)
558 {
559 WRITE_ONCE(page->compound_head, 0);
560 }
561
562 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
ClearPageCompound(struct page * page)563 static inline void ClearPageCompound(struct page *page)
564 {
565 BUG_ON(!PageHead(page));
566 ClearPageHead(page);
567 }
568 #endif
569
570 #define PG_head_mask ((1UL << PG_head))
571
572 #ifdef CONFIG_HUGETLB_PAGE
573 int PageHuge(struct page *page);
574 int PageHeadHuge(struct page *page);
575 bool page_huge_active(struct page *page);
576 #else
577 TESTPAGEFLAG_FALSE(Huge)
TESTPAGEFLAG_FALSE(HeadHuge)578 TESTPAGEFLAG_FALSE(HeadHuge)
579
580 static inline bool page_huge_active(struct page *page)
581 {
582 return 0;
583 }
584 #endif
585
586
587 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
588 /*
589 * PageHuge() only returns true for hugetlbfs pages, but not for
590 * normal or transparent huge pages.
591 *
592 * PageTransHuge() returns true for both transparent huge and
593 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
594 * called only in the core VM paths where hugetlbfs pages can't exist.
595 */
PageTransHuge(struct page * page)596 static inline int PageTransHuge(struct page *page)
597 {
598 VM_BUG_ON_PAGE(PageTail(page), page);
599 return PageHead(page);
600 }
601
602 /*
603 * PageTransCompound returns true for both transparent huge pages
604 * and hugetlbfs pages, so it should only be called when it's known
605 * that hugetlbfs pages aren't involved.
606 */
PageTransCompound(struct page * page)607 static inline int PageTransCompound(struct page *page)
608 {
609 return PageCompound(page);
610 }
611
612 /*
613 * PageTransCompoundMap is the same as PageTransCompound, but it also
614 * guarantees the primary MMU has the entire compound page mapped
615 * through pmd_trans_huge, which in turn guarantees the secondary MMUs
616 * can also map the entire compound page. This allows the secondary
617 * MMUs to call get_user_pages() only once for each compound page and
618 * to immediately map the entire compound page with a single secondary
619 * MMU fault. If there will be a pmd split later, the secondary MMUs
620 * will get an update through the MMU notifier invalidation through
621 * split_huge_pmd().
622 *
623 * Unlike PageTransCompound, this is safe to be called only while
624 * split_huge_pmd() cannot run from under us, like if protected by the
625 * MMU notifier, otherwise it may result in page->_mapcount check false
626 * positives.
627 *
628 * We have to treat page cache THP differently since every subpage of it
629 * would get _mapcount inc'ed once it is PMD mapped. But, it may be PTE
630 * mapped in the current process so comparing subpage's _mapcount to
631 * compound_mapcount to filter out PTE mapped case.
632 */
PageTransCompoundMap(struct page * page)633 static inline int PageTransCompoundMap(struct page *page)
634 {
635 struct page *head;
636
637 if (!PageTransCompound(page))
638 return 0;
639
640 if (PageAnon(page))
641 return atomic_read(&page->_mapcount) < 0;
642
643 head = compound_head(page);
644 /* File THP is PMD mapped and not PTE mapped */
645 return atomic_read(&page->_mapcount) ==
646 atomic_read(compound_mapcount_ptr(head));
647 }
648
649 /*
650 * PageTransTail returns true for both transparent huge pages
651 * and hugetlbfs pages, so it should only be called when it's known
652 * that hugetlbfs pages aren't involved.
653 */
PageTransTail(struct page * page)654 static inline int PageTransTail(struct page *page)
655 {
656 return PageTail(page);
657 }
658
659 /*
660 * PageDoubleMap indicates that the compound page is mapped with PTEs as well
661 * as PMDs.
662 *
663 * This is required for optimization of rmap operations for THP: we can postpone
664 * per small page mapcount accounting (and its overhead from atomic operations)
665 * until the first PMD split.
666 *
667 * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
668 * by one. This reference will go away with last compound_mapcount.
669 *
670 * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
671 */
PageDoubleMap(struct page * page)672 static inline int PageDoubleMap(struct page *page)
673 {
674 return PageHead(page) && test_bit(PG_double_map, &page[1].flags);
675 }
676
SetPageDoubleMap(struct page * page)677 static inline void SetPageDoubleMap(struct page *page)
678 {
679 VM_BUG_ON_PAGE(!PageHead(page), page);
680 set_bit(PG_double_map, &page[1].flags);
681 }
682
ClearPageDoubleMap(struct page * page)683 static inline void ClearPageDoubleMap(struct page *page)
684 {
685 VM_BUG_ON_PAGE(!PageHead(page), page);
686 clear_bit(PG_double_map, &page[1].flags);
687 }
TestSetPageDoubleMap(struct page * page)688 static inline int TestSetPageDoubleMap(struct page *page)
689 {
690 VM_BUG_ON_PAGE(!PageHead(page), page);
691 return test_and_set_bit(PG_double_map, &page[1].flags);
692 }
693
TestClearPageDoubleMap(struct page * page)694 static inline int TestClearPageDoubleMap(struct page *page)
695 {
696 VM_BUG_ON_PAGE(!PageHead(page), page);
697 return test_and_clear_bit(PG_double_map, &page[1].flags);
698 }
699
700 #else
701 TESTPAGEFLAG_FALSE(TransHuge)
TESTPAGEFLAG_FALSE(TransCompound)702 TESTPAGEFLAG_FALSE(TransCompound)
703 TESTPAGEFLAG_FALSE(TransCompoundMap)
704 TESTPAGEFLAG_FALSE(TransTail)
705 PAGEFLAG_FALSE(DoubleMap)
706 TESTSETFLAG_FALSE(DoubleMap)
707 TESTCLEARFLAG_FALSE(DoubleMap)
708 #endif
709
710 /*
711 * For pages that are never mapped to userspace (and aren't PageSlab),
712 * page_type may be used. Because it is initialised to -1, we invert the
713 * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
714 * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
715 * low bits so that an underflow or overflow of page_mapcount() won't be
716 * mistaken for a page type value.
717 */
718
719 #define PAGE_TYPE_BASE 0xf0000000
720 /* Reserve 0x0000007f to catch underflows of page_mapcount */
721 #define PAGE_MAPCOUNT_RESERVE -128
722 #define PG_buddy 0x00000080
723 #define PG_offline 0x00000100
724 #define PG_kmemcg 0x00000200
725 #define PG_table 0x00000400
726 #define PG_guard 0x00000800
727
728 #define PageType(page, flag) \
729 ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
730
731 static inline int page_has_type(struct page *page)
732 {
733 return (int)page->page_type < PAGE_MAPCOUNT_RESERVE;
734 }
735
736 #define PAGE_TYPE_OPS(uname, lname) \
737 static __always_inline int Page##uname(struct page *page) \
738 { \
739 return PageType(page, PG_##lname); \
740 } \
741 static __always_inline void __SetPage##uname(struct page *page) \
742 { \
743 VM_BUG_ON_PAGE(!PageType(page, 0), page); \
744 page->page_type &= ~PG_##lname; \
745 } \
746 static __always_inline void __ClearPage##uname(struct page *page) \
747 { \
748 VM_BUG_ON_PAGE(!Page##uname(page), page); \
749 page->page_type |= PG_##lname; \
750 }
751
752 /*
753 * PageBuddy() indicates that the page is free and in the buddy system
754 * (see mm/page_alloc.c).
755 */
756 PAGE_TYPE_OPS(Buddy, buddy)
757
758 /*
759 * PageOffline() indicates that the page is logically offline although the
760 * containing section is online. (e.g. inflated in a balloon driver or
761 * not onlined when onlining the section).
762 * The content of these pages is effectively stale. Such pages should not
763 * be touched (read/write/dump/save) except by their owner.
764 */
765 PAGE_TYPE_OPS(Offline, offline)
766
767 /*
768 * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on
769 * pages allocated with __GFP_ACCOUNT. It gets cleared on page free.
770 */
771 PAGE_TYPE_OPS(Kmemcg, kmemcg)
772
773 /*
774 * Marks pages in use as page tables.
775 */
776 PAGE_TYPE_OPS(Table, table)
777
778 /*
779 * Marks guardpages used with debug_pagealloc.
780 */
781 PAGE_TYPE_OPS(Guard, guard)
782
783 extern bool is_free_buddy_page(struct page *page);
784
785 __PAGEFLAG(Isolated, isolated, PF_ANY);
786
787 /*
788 * If network-based swap is enabled, sl*b must keep track of whether pages
789 * were allocated from pfmemalloc reserves.
790 */
PageSlabPfmemalloc(struct page * page)791 static inline int PageSlabPfmemalloc(struct page *page)
792 {
793 VM_BUG_ON_PAGE(!PageSlab(page), page);
794 return PageActive(page);
795 }
796
SetPageSlabPfmemalloc(struct page * page)797 static inline void SetPageSlabPfmemalloc(struct page *page)
798 {
799 VM_BUG_ON_PAGE(!PageSlab(page), page);
800 SetPageActive(page);
801 }
802
__ClearPageSlabPfmemalloc(struct page * page)803 static inline void __ClearPageSlabPfmemalloc(struct page *page)
804 {
805 VM_BUG_ON_PAGE(!PageSlab(page), page);
806 __ClearPageActive(page);
807 }
808
ClearPageSlabPfmemalloc(struct page * page)809 static inline void ClearPageSlabPfmemalloc(struct page *page)
810 {
811 VM_BUG_ON_PAGE(!PageSlab(page), page);
812 ClearPageActive(page);
813 }
814
815 #ifdef CONFIG_MMU
816 #define __PG_MLOCKED (1UL << PG_mlocked)
817 #else
818 #define __PG_MLOCKED 0
819 #endif
820
821 /*
822 * Flags checked when a page is freed. Pages being freed should not have
823 * these flags set. It they are, there is a problem.
824 */
825 #define PAGE_FLAGS_CHECK_AT_FREE \
826 (1UL << PG_lru | 1UL << PG_locked | \
827 1UL << PG_private | 1UL << PG_private_2 | \
828 1UL << PG_writeback | 1UL << PG_reserved | \
829 1UL << PG_slab | 1UL << PG_active | \
830 1UL << PG_unevictable | __PG_MLOCKED)
831
832 /*
833 * Flags checked when a page is prepped for return by the page allocator.
834 * Pages being prepped should not have these flags set. It they are set,
835 * there has been a kernel bug or struct page corruption.
836 *
837 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
838 * alloc-free cycle to prevent from reusing the page.
839 */
840 #define PAGE_FLAGS_CHECK_AT_PREP \
841 (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
842
843 #define PAGE_FLAGS_PRIVATE \
844 (1UL << PG_private | 1UL << PG_private_2)
845 /**
846 * page_has_private - Determine if page has private stuff
847 * @page: The page to be checked
848 *
849 * Determine if a page has private stuff, indicating that release routines
850 * should be invoked upon it.
851 */
page_has_private(struct page * page)852 static inline int page_has_private(struct page *page)
853 {
854 return !!(page->flags & PAGE_FLAGS_PRIVATE);
855 }
856
857 #undef PF_ANY
858 #undef PF_HEAD
859 #undef PF_ONLY_HEAD
860 #undef PF_NO_TAIL
861 #undef PF_NO_COMPOUND
862 #endif /* !__GENERATING_BOUNDS_H */
863
864 #endif /* PAGE_FLAGS_H */
865
