Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Macros for manipulating and testing page->flags | |
3 | */ | |
4 | ||
5 | #ifndef PAGE_FLAGS_H | |
6 | #define PAGE_FLAGS_H | |
7 | ||
f886ed44 | 8 | #include <linux/types.h> |
187f1882 | 9 | #include <linux/bug.h> |
072bb0aa | 10 | #include <linux/mmdebug.h> |
9223b419 | 11 | #ifndef __GENERATING_BOUNDS_H |
6d777953 | 12 | #include <linux/mm_types.h> |
01fc0ac1 | 13 | #include <generated/bounds.h> |
9223b419 | 14 | #endif /* !__GENERATING_BOUNDS_H */ |
f886ed44 | 15 | |
1da177e4 LT |
16 | /* |
17 | * Various page->flags bits: | |
18 | * | |
19 | * PG_reserved is set for special pages, which can never be swapped out. Some | |
20 | * of them might not even exist (eg empty_bad_page)... | |
21 | * | |
da6052f7 NP |
22 | * The PG_private bitflag is set on pagecache pages if they contain filesystem |
23 | * specific data (which is normally at page->private). It can be used by | |
24 | * private allocations for its own usage. | |
1da177e4 | 25 | * |
da6052f7 NP |
26 | * During initiation of disk I/O, PG_locked is set. This bit is set before I/O |
27 | * and cleared when writeback _starts_ or when read _completes_. PG_writeback | |
28 | * is set before writeback starts and cleared when it finishes. | |
29 | * | |
30 | * PG_locked also pins a page in pagecache, and blocks truncation of the file | |
31 | * while it is held. | |
32 | * | |
33 | * page_waitqueue(page) is a wait queue of all tasks waiting for the page | |
34 | * to become unlocked. | |
1da177e4 LT |
35 | * |
36 | * PG_uptodate tells whether the page's contents is valid. When a read | |
37 | * completes, the page becomes uptodate, unless a disk I/O error happened. | |
38 | * | |
da6052f7 NP |
39 | * PG_referenced, PG_reclaim are used for page reclaim for anonymous and |
40 | * file-backed pagecache (see mm/vmscan.c). | |
1da177e4 LT |
41 | * |
42 | * PG_error is set to indicate that an I/O error occurred on this page. | |
43 | * | |
44 | * PG_arch_1 is an architecture specific page state bit. The generic code | |
45 | * guarantees that this bit is cleared for a page when it first is entered into | |
46 | * the page cache. | |
47 | * | |
48 | * PG_highmem pages are not permanently mapped into the kernel virtual address | |
49 | * space, they need to be kmapped separately for doing IO on the pages. The | |
50 | * struct page (these bits with information) are always mapped into kernel | |
51 | * address space... | |
da6052f7 | 52 | * |
d466f2fc AK |
53 | * PG_hwpoison indicates that a page got corrupted in hardware and contains |
54 | * data with incorrect ECC bits that triggered a machine check. Accessing is | |
55 | * not safe since it may cause another machine check. Don't touch! | |
1da177e4 LT |
56 | */ |
57 | ||
58 | /* | |
59 | * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break | |
91fc8ab3 AW |
60 | * locked- and dirty-page accounting. |
61 | * | |
62 | * The page flags field is split into two parts, the main flags area | |
63 | * which extends from the low bits upwards, and the fields area which | |
64 | * extends from the high bits downwards. | |
65 | * | |
66 | * | FIELD | ... | FLAGS | | |
9223b419 CL |
67 | * N-1 ^ 0 |
68 | * (NR_PAGEFLAGS) | |
91fc8ab3 | 69 | * |
9223b419 CL |
70 | * The fields area is reserved for fields mapping zone, node (for NUMA) and |
71 | * SPARSEMEM section (for variants of SPARSEMEM that require section ids like | |
72 | * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). | |
1da177e4 | 73 | */ |
e2683181 CL |
74 | enum pageflags { |
75 | PG_locked, /* Page is locked. Don't touch. */ | |
76 | PG_error, | |
77 | PG_referenced, | |
78 | PG_uptodate, | |
79 | PG_dirty, | |
80 | PG_lru, | |
81 | PG_active, | |
82 | PG_slab, | |
83 | PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ | |
e2683181 CL |
84 | PG_arch_1, |
85 | PG_reserved, | |
86 | PG_private, /* If pagecache, has fs-private data */ | |
266cf658 | 87 | PG_private_2, /* If pagecache, has fs aux data */ |
e2683181 | 88 | PG_writeback, /* Page is under writeback */ |
e20b8cca CL |
89 | #ifdef CONFIG_PAGEFLAGS_EXTENDED |
90 | PG_head, /* A head page */ | |
91 | PG_tail, /* A tail page */ | |
92 | #else | |
e2683181 | 93 | PG_compound, /* A compound page */ |
e20b8cca | 94 | #endif |
e2683181 CL |
95 | PG_swapcache, /* Swap page: swp_entry_t in private */ |
96 | PG_mappedtodisk, /* Has blocks allocated on-disk */ | |
97 | PG_reclaim, /* To be reclaimed asap */ | |
b2e18538 | 98 | PG_swapbacked, /* Page is backed by RAM/swap */ |
894bc310 | 99 | PG_unevictable, /* Page is "unevictable" */ |
af8e3354 | 100 | #ifdef CONFIG_MMU |
b291f000 | 101 | PG_mlocked, /* Page is vma mlocked */ |
894bc310 | 102 | #endif |
46cf98cd | 103 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
602c4d11 | 104 | PG_uncached, /* Page has been mapped as uncached */ |
d466f2fc AK |
105 | #endif |
106 | #ifdef CONFIG_MEMORY_FAILURE | |
107 | PG_hwpoison, /* hardware poisoned page. Don't touch */ | |
e9da73d6 AA |
108 | #endif |
109 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
110 | PG_compound_lock, | |
f886ed44 | 111 | #endif |
0cad47cf AW |
112 | __NR_PAGEFLAGS, |
113 | ||
114 | /* Filesystems */ | |
115 | PG_checked = PG_owner_priv_1, | |
116 | ||
266cf658 DH |
117 | /* Two page bits are conscripted by FS-Cache to maintain local caching |
118 | * state. These bits are set on pages belonging to the netfs's inodes | |
119 | * when those inodes are being locally cached. | |
120 | */ | |
121 | PG_fscache = PG_private_2, /* page backed by cache */ | |
122 | ||
0cad47cf | 123 | /* XEN */ |
d8ac3dd4 | 124 | /* Pinned in Xen as a read-only pagetable page. */ |
0cad47cf | 125 | PG_pinned = PG_owner_priv_1, |
d8ac3dd4 | 126 | /* Pinned as part of domain save (see xen_mm_pin_all()). */ |
0cad47cf | 127 | PG_savepinned = PG_dirty, |
d8ac3dd4 JH |
128 | /* Has a grant mapping of another (foreign) domain's page. */ |
129 | PG_foreign = PG_owner_priv_1, | |
8a38082d | 130 | |
9023cb7e | 131 | /* SLOB */ |
9023cb7e | 132 | PG_slob_free = PG_private, |
e2683181 | 133 | }; |
1da177e4 | 134 | |
9223b419 CL |
135 | #ifndef __GENERATING_BOUNDS_H |
136 | ||
f94a62e9 CL |
137 | /* |
138 | * Macros to create function definitions for page flags | |
139 | */ | |
140 | #define TESTPAGEFLAG(uname, lname) \ | |
67db392d | 141 | static inline int Page##uname(const struct page *page) \ |
f94a62e9 CL |
142 | { return test_bit(PG_##lname, &page->flags); } |
143 | ||
144 | #define SETPAGEFLAG(uname, lname) \ | |
145 | static inline void SetPage##uname(struct page *page) \ | |
146 | { set_bit(PG_##lname, &page->flags); } | |
147 | ||
148 | #define CLEARPAGEFLAG(uname, lname) \ | |
149 | static inline void ClearPage##uname(struct page *page) \ | |
150 | { clear_bit(PG_##lname, &page->flags); } | |
151 | ||
152 | #define __SETPAGEFLAG(uname, lname) \ | |
153 | static inline void __SetPage##uname(struct page *page) \ | |
154 | { __set_bit(PG_##lname, &page->flags); } | |
155 | ||
156 | #define __CLEARPAGEFLAG(uname, lname) \ | |
157 | static inline void __ClearPage##uname(struct page *page) \ | |
158 | { __clear_bit(PG_##lname, &page->flags); } | |
159 | ||
160 | #define TESTSETFLAG(uname, lname) \ | |
161 | static inline int TestSetPage##uname(struct page *page) \ | |
162 | { return test_and_set_bit(PG_##lname, &page->flags); } | |
163 | ||
164 | #define TESTCLEARFLAG(uname, lname) \ | |
165 | static inline int TestClearPage##uname(struct page *page) \ | |
166 | { return test_and_clear_bit(PG_##lname, &page->flags); } | |
167 | ||
451ea25d JW |
168 | #define __TESTCLEARFLAG(uname, lname) \ |
169 | static inline int __TestClearPage##uname(struct page *page) \ | |
170 | { return __test_and_clear_bit(PG_##lname, &page->flags); } | |
f94a62e9 CL |
171 | |
172 | #define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ | |
173 | SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname) | |
174 | ||
175 | #define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ | |
176 | __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname) | |
177 | ||
178 | #define TESTSCFLAG(uname, lname) \ | |
179 | TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname) | |
180 | ||
2f3e442c JW |
181 | #define TESTPAGEFLAG_FALSE(uname) \ |
182 | static inline int Page##uname(const struct page *page) { return 0; } | |
183 | ||
8a7a8544 LS |
184 | #define SETPAGEFLAG_NOOP(uname) \ |
185 | static inline void SetPage##uname(struct page *page) { } | |
186 | ||
187 | #define CLEARPAGEFLAG_NOOP(uname) \ | |
188 | static inline void ClearPage##uname(struct page *page) { } | |
189 | ||
190 | #define __CLEARPAGEFLAG_NOOP(uname) \ | |
191 | static inline void __ClearPage##uname(struct page *page) { } | |
192 | ||
2f3e442c JW |
193 | #define TESTSETFLAG_FALSE(uname) \ |
194 | static inline int TestSetPage##uname(struct page *page) { return 0; } | |
195 | ||
8a7a8544 LS |
196 | #define TESTCLEARFLAG_FALSE(uname) \ |
197 | static inline int TestClearPage##uname(struct page *page) { return 0; } | |
198 | ||
451ea25d JW |
199 | #define __TESTCLEARFLAG_FALSE(uname) \ |
200 | static inline int __TestClearPage##uname(struct page *page) { return 0; } | |
201 | ||
2f3e442c JW |
202 | #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \ |
203 | SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname) | |
204 | ||
205 | #define TESTSCFLAG_FALSE(uname) \ | |
206 | TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) | |
207 | ||
6a1e7f77 CL |
208 | struct page; /* forward declaration */ |
209 | ||
cb240452 | 210 | TESTPAGEFLAG(Locked, locked) |
212260aa | 211 | PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error) |
6a1e7f77 | 212 | PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) |
2457aec6 | 213 | __SETPAGEFLAG(Referenced, referenced) |
6a1e7f77 CL |
214 | PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) |
215 | PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) | |
216 | PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active) | |
894bc310 | 217 | TESTCLEARFLAG(Active, active) |
6a1e7f77 | 218 | __PAGEFLAG(Slab, slab) |
0cad47cf AW |
219 | PAGEFLAG(Checked, checked) /* Used by some filesystems */ |
220 | PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */ | |
221 | PAGEFLAG(SavePinned, savepinned); /* Xen */ | |
d8ac3dd4 | 222 | PAGEFLAG(Foreign, foreign); /* Xen */ |
6a1e7f77 | 223 | PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) |
b2e18538 | 224 | PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) |
07a42788 | 225 | __SETPAGEFLAG(SwapBacked, swapbacked) |
6a1e7f77 | 226 | |
9023cb7e AW |
227 | __PAGEFLAG(SlobFree, slob_free) |
228 | ||
266cf658 DH |
229 | /* |
230 | * Private page markings that may be used by the filesystem that owns the page | |
231 | * for its own purposes. | |
232 | * - PG_private and PG_private_2 cause releasepage() and co to be invoked | |
233 | */ | |
234 | PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private) | |
235 | __CLEARPAGEFLAG(Private, private) | |
236 | PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2) | |
237 | PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1) | |
238 | ||
6a1e7f77 CL |
239 | /* |
240 | * Only test-and-set exist for PG_writeback. The unconditional operators are | |
241 | * risky: they bypass page accounting. | |
242 | */ | |
243 | TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback) | |
6a1e7f77 CL |
244 | PAGEFLAG(MappedToDisk, mappedtodisk) |
245 | ||
579f8290 | 246 | /* PG_readahead is only used for reads; PG_reclaim is only for writes */ |
6a1e7f77 | 247 | PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim) |
579f8290 | 248 | PAGEFLAG(Readahead, reclaim) TESTCLEARFLAG(Readahead, reclaim) |
6a1e7f77 CL |
249 | |
250 | #ifdef CONFIG_HIGHMEM | |
1da177e4 | 251 | /* |
6a1e7f77 CL |
252 | * Must use a macro here due to header dependency issues. page_zone() is not |
253 | * available at this point. | |
1da177e4 | 254 | */ |
0a128b2b | 255 | #define PageHighMem(__p) is_highmem(page_zone(__p)) |
6a1e7f77 | 256 | #else |
ec7cade8 | 257 | PAGEFLAG_FALSE(HighMem) |
6a1e7f77 CL |
258 | #endif |
259 | ||
260 | #ifdef CONFIG_SWAP | |
261 | PAGEFLAG(SwapCache, swapcache) | |
262 | #else | |
ec7cade8 | 263 | PAGEFLAG_FALSE(SwapCache) |
6a1e7f77 CL |
264 | #endif |
265 | ||
894bc310 LS |
266 | PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) |
267 | TESTCLEARFLAG(Unevictable, unevictable) | |
b291f000 | 268 | |
af8e3354 | 269 | #ifdef CONFIG_MMU |
b291f000 | 270 | PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked) |
451ea25d | 271 | TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked) |
894bc310 | 272 | #else |
2f3e442c JW |
273 | PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked) |
274 | TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked) | |
894bc310 LS |
275 | #endif |
276 | ||
46cf98cd | 277 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
6a1e7f77 | 278 | PAGEFLAG(Uncached, uncached) |
602c4d11 | 279 | #else |
ec7cade8 | 280 | PAGEFLAG_FALSE(Uncached) |
6a1e7f77 | 281 | #endif |
1da177e4 | 282 | |
d466f2fc AK |
283 | #ifdef CONFIG_MEMORY_FAILURE |
284 | PAGEFLAG(HWPoison, hwpoison) | |
847ce401 | 285 | TESTSCFLAG(HWPoison, hwpoison) |
d466f2fc AK |
286 | #define __PG_HWPOISON (1UL << PG_hwpoison) |
287 | #else | |
288 | PAGEFLAG_FALSE(HWPoison) | |
289 | #define __PG_HWPOISON 0 | |
290 | #endif | |
291 | ||
e8c6158f KS |
292 | /* |
293 | * On an anonymous page mapped into a user virtual memory area, | |
294 | * page->mapping points to its anon_vma, not to a struct address_space; | |
295 | * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. | |
296 | * | |
297 | * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, | |
298 | * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit; | |
299 | * and then page->mapping points, not to an anon_vma, but to a private | |
300 | * structure which KSM associates with that merged page. See ksm.h. | |
301 | * | |
302 | * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used. | |
303 | * | |
304 | * Please note that, confusingly, "page_mapping" refers to the inode | |
305 | * address_space which maps the page from disk; whereas "page_mapped" | |
306 | * refers to user virtual address space into which the page is mapped. | |
307 | */ | |
308 | #define PAGE_MAPPING_ANON 1 | |
309 | #define PAGE_MAPPING_KSM 2 | |
310 | #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM) | |
311 | ||
312 | static inline int PageAnon(struct page *page) | |
313 | { | |
314 | return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; | |
315 | } | |
316 | ||
317 | #ifdef CONFIG_KSM | |
318 | /* | |
319 | * A KSM page is one of those write-protected "shared pages" or "merged pages" | |
320 | * which KSM maps into multiple mms, wherever identical anonymous page content | |
321 | * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any | |
322 | * anon_vma, but to that page's node of the stable tree. | |
323 | */ | |
324 | static inline int PageKsm(struct page *page) | |
325 | { | |
326 | return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == | |
327 | (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); | |
328 | } | |
329 | #else | |
330 | TESTPAGEFLAG_FALSE(Ksm) | |
331 | #endif | |
332 | ||
1a9b5b7f WF |
333 | u64 stable_page_flags(struct page *page); |
334 | ||
0ed361de NP |
335 | static inline int PageUptodate(struct page *page) |
336 | { | |
337 | int ret = test_bit(PG_uptodate, &(page)->flags); | |
338 | ||
339 | /* | |
340 | * Must ensure that the data we read out of the page is loaded | |
341 | * _after_ we've loaded page->flags to check for PageUptodate. | |
342 | * We can skip the barrier if the page is not uptodate, because | |
343 | * we wouldn't be reading anything from it. | |
344 | * | |
345 | * See SetPageUptodate() for the other side of the story. | |
346 | */ | |
347 | if (ret) | |
348 | smp_rmb(); | |
349 | ||
350 | return ret; | |
351 | } | |
352 | ||
353 | static inline void __SetPageUptodate(struct page *page) | |
354 | { | |
355 | smp_wmb(); | |
356 | __set_bit(PG_uptodate, &(page)->flags); | |
0ed361de NP |
357 | } |
358 | ||
2dcea57a HC |
359 | static inline void SetPageUptodate(struct page *page) |
360 | { | |
0ed361de NP |
361 | /* |
362 | * Memory barrier must be issued before setting the PG_uptodate bit, | |
363 | * so that all previous stores issued in order to bring the page | |
364 | * uptodate are actually visible before PageUptodate becomes true. | |
0ed361de NP |
365 | */ |
366 | smp_wmb(); | |
367 | set_bit(PG_uptodate, &(page)->flags); | |
0ed361de NP |
368 | } |
369 | ||
6a1e7f77 | 370 | CLEARPAGEFLAG(Uptodate, uptodate) |
1da177e4 | 371 | |
6a1e7f77 | 372 | int test_clear_page_writeback(struct page *page); |
1c8349a1 NJ |
373 | int __test_set_page_writeback(struct page *page, bool keep_write); |
374 | ||
375 | #define test_set_page_writeback(page) \ | |
376 | __test_set_page_writeback(page, false) | |
377 | #define test_set_page_writeback_keepwrite(page) \ | |
378 | __test_set_page_writeback(page, true) | |
1da177e4 | 379 | |
6a1e7f77 CL |
380 | static inline void set_page_writeback(struct page *page) |
381 | { | |
382 | test_set_page_writeback(page); | |
383 | } | |
1da177e4 | 384 | |
1c8349a1 NJ |
385 | static inline void set_page_writeback_keepwrite(struct page *page) |
386 | { | |
387 | test_set_page_writeback_keepwrite(page); | |
388 | } | |
389 | ||
e20b8cca CL |
390 | #ifdef CONFIG_PAGEFLAGS_EXTENDED |
391 | /* | |
392 | * System with lots of page flags available. This allows separate | |
393 | * flags for PageHead() and PageTail() checks of compound pages so that bit | |
394 | * tests can be used in performance sensitive paths. PageCompound is | |
8e0861fa AK |
395 | * generally not used in hot code paths except arch/powerpc/mm/init_64.c |
396 | * and arch/powerpc/kvm/book3s_64_vio_hv.c which use it to detect huge pages | |
397 | * and avoid handling those in real mode. | |
e20b8cca | 398 | */ |
4e6af67e | 399 | __PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head) |
e20b8cca CL |
400 | __PAGEFLAG(Tail, tail) |
401 | ||
402 | static inline int PageCompound(struct page *page) | |
403 | { | |
404 | return page->flags & ((1L << PG_head) | (1L << PG_tail)); | |
405 | ||
406 | } | |
4e6af67e AA |
407 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
408 | static inline void ClearPageCompound(struct page *page) | |
409 | { | |
410 | BUG_ON(!PageHead(page)); | |
411 | ClearPageHead(page); | |
412 | } | |
413 | #endif | |
b3acc56b PT |
414 | |
415 | #define PG_head_mask ((1L << PG_head)) | |
416 | ||
e20b8cca CL |
417 | #else |
418 | /* | |
419 | * Reduce page flag use as much as possible by overlapping | |
420 | * compound page flags with the flags used for page cache pages. Possible | |
421 | * because PageCompound is always set for compound pages and not for | |
422 | * pages on the LRU and/or pagecache. | |
423 | */ | |
6a1e7f77 | 424 | TESTPAGEFLAG(Compound, compound) |
ad4b3fb7 | 425 | __SETPAGEFLAG(Head, compound) __CLEARPAGEFLAG(Head, compound) |
1da177e4 | 426 | |
d85f3385 | 427 | /* |
6d777953 | 428 | * PG_reclaim is used in combination with PG_compound to mark the |
6a1e7f77 CL |
429 | * head and tail of a compound page. This saves one page flag |
430 | * but makes it impossible to use compound pages for the page cache. | |
431 | * The PG_reclaim bit would have to be used for reclaim or readahead | |
432 | * if compound pages enter the page cache. | |
6d777953 CL |
433 | * |
434 | * PG_compound & PG_reclaim => Tail page | |
435 | * PG_compound & ~PG_reclaim => Head page | |
d85f3385 | 436 | */ |
ad4b3fb7 | 437 | #define PG_head_mask ((1L << PG_compound)) |
6d777953 CL |
438 | #define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) |
439 | ||
ad4b3fb7 CD |
440 | static inline int PageHead(struct page *page) |
441 | { | |
442 | return ((page->flags & PG_head_tail_mask) == PG_head_mask); | |
443 | } | |
444 | ||
6a1e7f77 CL |
445 | static inline int PageTail(struct page *page) |
446 | { | |
447 | return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask); | |
448 | } | |
6d777953 CL |
449 | |
450 | static inline void __SetPageTail(struct page *page) | |
451 | { | |
452 | page->flags |= PG_head_tail_mask; | |
453 | } | |
454 | ||
455 | static inline void __ClearPageTail(struct page *page) | |
456 | { | |
457 | page->flags &= ~PG_head_tail_mask; | |
458 | } | |
459 | ||
4e6af67e AA |
460 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
461 | static inline void ClearPageCompound(struct page *page) | |
462 | { | |
463 | BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound)); | |
464 | clear_bit(PG_compound, &page->flags); | |
465 | } | |
466 | #endif | |
467 | ||
e20b8cca | 468 | #endif /* !PAGEFLAGS_EXTENDED */ |
dfa7e20c | 469 | |
e8c6158f KS |
470 | #ifdef CONFIG_HUGETLB_PAGE |
471 | int PageHuge(struct page *page); | |
472 | int PageHeadHuge(struct page *page); | |
7e1f049e | 473 | bool page_huge_active(struct page *page); |
e8c6158f KS |
474 | #else |
475 | TESTPAGEFLAG_FALSE(Huge) | |
476 | TESTPAGEFLAG_FALSE(HeadHuge) | |
7e1f049e NH |
477 | |
478 | static inline bool page_huge_active(struct page *page) | |
479 | { | |
480 | return 0; | |
481 | } | |
e8c6158f KS |
482 | #endif |
483 | ||
7e1f049e | 484 | |
936a5fe6 | 485 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
71e3aac0 AA |
486 | /* |
487 | * PageHuge() only returns true for hugetlbfs pages, but not for | |
488 | * normal or transparent huge pages. | |
489 | * | |
490 | * PageTransHuge() returns true for both transparent huge and | |
491 | * hugetlbfs pages, but not normal pages. PageTransHuge() can only be | |
492 | * called only in the core VM paths where hugetlbfs pages can't exist. | |
493 | */ | |
494 | static inline int PageTransHuge(struct page *page) | |
495 | { | |
309381fe | 496 | VM_BUG_ON_PAGE(PageTail(page), page); |
71e3aac0 AA |
497 | return PageHead(page); |
498 | } | |
499 | ||
385de357 DN |
500 | /* |
501 | * PageTransCompound returns true for both transparent huge pages | |
502 | * and hugetlbfs pages, so it should only be called when it's known | |
503 | * that hugetlbfs pages aren't involved. | |
504 | */ | |
936a5fe6 AA |
505 | static inline int PageTransCompound(struct page *page) |
506 | { | |
507 | return PageCompound(page); | |
508 | } | |
71e3aac0 | 509 | |
385de357 DN |
510 | /* |
511 | * PageTransTail returns true for both transparent huge pages | |
512 | * and hugetlbfs pages, so it should only be called when it's known | |
513 | * that hugetlbfs pages aren't involved. | |
514 | */ | |
515 | static inline int PageTransTail(struct page *page) | |
516 | { | |
517 | return PageTail(page); | |
518 | } | |
519 | ||
936a5fe6 | 520 | #else |
71e3aac0 AA |
521 | |
522 | static inline int PageTransHuge(struct page *page) | |
523 | { | |
524 | return 0; | |
525 | } | |
526 | ||
936a5fe6 AA |
527 | static inline int PageTransCompound(struct page *page) |
528 | { | |
529 | return 0; | |
530 | } | |
385de357 DN |
531 | |
532 | static inline int PageTransTail(struct page *page) | |
533 | { | |
534 | return 0; | |
535 | } | |
936a5fe6 AA |
536 | #endif |
537 | ||
e8c6158f KS |
538 | /* |
539 | * PageBuddy() indicate that the page is free and in the buddy system | |
540 | * (see mm/page_alloc.c). | |
541 | * | |
542 | * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to | |
543 | * -2 so that an underflow of the page_mapcount() won't be mistaken | |
544 | * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very | |
545 | * efficiently by most CPU architectures. | |
546 | */ | |
547 | #define PAGE_BUDDY_MAPCOUNT_VALUE (-128) | |
548 | ||
549 | static inline int PageBuddy(struct page *page) | |
550 | { | |
551 | return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE; | |
552 | } | |
553 | ||
554 | static inline void __SetPageBuddy(struct page *page) | |
555 | { | |
556 | VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); | |
557 | atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE); | |
558 | } | |
559 | ||
560 | static inline void __ClearPageBuddy(struct page *page) | |
561 | { | |
562 | VM_BUG_ON_PAGE(!PageBuddy(page), page); | |
563 | atomic_set(&page->_mapcount, -1); | |
564 | } | |
565 | ||
566 | #define PAGE_BALLOON_MAPCOUNT_VALUE (-256) | |
567 | ||
568 | static inline int PageBalloon(struct page *page) | |
569 | { | |
570 | return atomic_read(&page->_mapcount) == PAGE_BALLOON_MAPCOUNT_VALUE; | |
571 | } | |
572 | ||
573 | static inline void __SetPageBalloon(struct page *page) | |
574 | { | |
575 | VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); | |
576 | atomic_set(&page->_mapcount, PAGE_BALLOON_MAPCOUNT_VALUE); | |
577 | } | |
578 | ||
579 | static inline void __ClearPageBalloon(struct page *page) | |
580 | { | |
581 | VM_BUG_ON_PAGE(!PageBalloon(page), page); | |
582 | atomic_set(&page->_mapcount, -1); | |
583 | } | |
584 | ||
072bb0aa MG |
585 | /* |
586 | * If network-based swap is enabled, sl*b must keep track of whether pages | |
587 | * were allocated from pfmemalloc reserves. | |
588 | */ | |
589 | static inline int PageSlabPfmemalloc(struct page *page) | |
590 | { | |
309381fe | 591 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
072bb0aa MG |
592 | return PageActive(page); |
593 | } | |
594 | ||
595 | static inline void SetPageSlabPfmemalloc(struct page *page) | |
596 | { | |
309381fe | 597 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
072bb0aa MG |
598 | SetPageActive(page); |
599 | } | |
600 | ||
601 | static inline void __ClearPageSlabPfmemalloc(struct page *page) | |
602 | { | |
309381fe | 603 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
072bb0aa MG |
604 | __ClearPageActive(page); |
605 | } | |
606 | ||
607 | static inline void ClearPageSlabPfmemalloc(struct page *page) | |
608 | { | |
309381fe | 609 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
072bb0aa MG |
610 | ClearPageActive(page); |
611 | } | |
612 | ||
af8e3354 | 613 | #ifdef CONFIG_MMU |
33925b25 DH |
614 | #define __PG_MLOCKED (1 << PG_mlocked) |
615 | #else | |
b291f000 | 616 | #define __PG_MLOCKED 0 |
894bc310 LS |
617 | #endif |
618 | ||
e9da73d6 AA |
619 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
620 | #define __PG_COMPOUND_LOCK (1 << PG_compound_lock) | |
621 | #else | |
622 | #define __PG_COMPOUND_LOCK 0 | |
623 | #endif | |
624 | ||
dfa7e20c RA |
625 | /* |
626 | * Flags checked when a page is freed. Pages being freed should not have | |
627 | * these flags set. It they are, there is a problem. | |
628 | */ | |
79f4b7bf | 629 | #define PAGE_FLAGS_CHECK_AT_FREE \ |
266cf658 DH |
630 | (1 << PG_lru | 1 << PG_locked | \ |
631 | 1 << PG_private | 1 << PG_private_2 | \ | |
5f24ce5f | 632 | 1 << PG_writeback | 1 << PG_reserved | \ |
266cf658 | 633 | 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ |
e9da73d6 AA |
634 | 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \ |
635 | __PG_COMPOUND_LOCK) | |
dfa7e20c RA |
636 | |
637 | /* | |
638 | * Flags checked when a page is prepped for return by the page allocator. | |
79f4b7bf HD |
639 | * Pages being prepped should not have any flags set. It they are set, |
640 | * there has been a kernel bug or struct page corruption. | |
dfa7e20c | 641 | */ |
79f4b7bf | 642 | #define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1) |
dfa7e20c | 643 | |
edcf4748 JW |
644 | #define PAGE_FLAGS_PRIVATE \ |
645 | (1 << PG_private | 1 << PG_private_2) | |
266cf658 DH |
646 | /** |
647 | * page_has_private - Determine if page has private stuff | |
648 | * @page: The page to be checked | |
649 | * | |
650 | * Determine if a page has private stuff, indicating that release routines | |
651 | * should be invoked upon it. | |
652 | */ | |
edcf4748 JW |
653 | static inline int page_has_private(struct page *page) |
654 | { | |
655 | return !!(page->flags & PAGE_FLAGS_PRIVATE); | |
656 | } | |
657 | ||
658 | #endif /* !__GENERATING_BOUNDS_H */ | |
266cf658 | 659 | |
1da177e4 | 660 | #endif /* PAGE_FLAGS_H */ |