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> |
9223b419 | 9 | #ifndef __GENERATING_BOUNDS_H |
6d777953 | 10 | #include <linux/mm_types.h> |
9223b419 CL |
11 | #include <linux/bounds.h> |
12 | #endif /* !__GENERATING_BOUNDS_H */ | |
f886ed44 | 13 | |
1da177e4 LT |
14 | /* |
15 | * Various page->flags bits: | |
16 | * | |
17 | * PG_reserved is set for special pages, which can never be swapped out. Some | |
18 | * of them might not even exist (eg empty_bad_page)... | |
19 | * | |
da6052f7 NP |
20 | * The PG_private bitflag is set on pagecache pages if they contain filesystem |
21 | * specific data (which is normally at page->private). It can be used by | |
22 | * private allocations for its own usage. | |
1da177e4 | 23 | * |
da6052f7 NP |
24 | * During initiation of disk I/O, PG_locked is set. This bit is set before I/O |
25 | * and cleared when writeback _starts_ or when read _completes_. PG_writeback | |
26 | * is set before writeback starts and cleared when it finishes. | |
27 | * | |
28 | * PG_locked also pins a page in pagecache, and blocks truncation of the file | |
29 | * while it is held. | |
30 | * | |
31 | * page_waitqueue(page) is a wait queue of all tasks waiting for the page | |
32 | * to become unlocked. | |
1da177e4 LT |
33 | * |
34 | * PG_uptodate tells whether the page's contents is valid. When a read | |
35 | * completes, the page becomes uptodate, unless a disk I/O error happened. | |
36 | * | |
da6052f7 NP |
37 | * PG_referenced, PG_reclaim are used for page reclaim for anonymous and |
38 | * file-backed pagecache (see mm/vmscan.c). | |
1da177e4 LT |
39 | * |
40 | * PG_error is set to indicate that an I/O error occurred on this page. | |
41 | * | |
42 | * PG_arch_1 is an architecture specific page state bit. The generic code | |
43 | * guarantees that this bit is cleared for a page when it first is entered into | |
44 | * the page cache. | |
45 | * | |
46 | * PG_highmem pages are not permanently mapped into the kernel virtual address | |
47 | * space, they need to be kmapped separately for doing IO on the pages. The | |
48 | * struct page (these bits with information) are always mapped into kernel | |
49 | * address space... | |
da6052f7 NP |
50 | * |
51 | * PG_buddy is set to indicate that the page is free and in the buddy system | |
52 | * (see mm/page_alloc.c). | |
53 | * | |
1da177e4 LT |
54 | */ |
55 | ||
56 | /* | |
57 | * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break | |
91fc8ab3 AW |
58 | * locked- and dirty-page accounting. |
59 | * | |
60 | * The page flags field is split into two parts, the main flags area | |
61 | * which extends from the low bits upwards, and the fields area which | |
62 | * extends from the high bits downwards. | |
63 | * | |
64 | * | FIELD | ... | FLAGS | | |
9223b419 CL |
65 | * N-1 ^ 0 |
66 | * (NR_PAGEFLAGS) | |
91fc8ab3 | 67 | * |
9223b419 CL |
68 | * The fields area is reserved for fields mapping zone, node (for NUMA) and |
69 | * SPARSEMEM section (for variants of SPARSEMEM that require section ids like | |
70 | * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). | |
1da177e4 | 71 | */ |
e2683181 CL |
72 | enum pageflags { |
73 | PG_locked, /* Page is locked. Don't touch. */ | |
74 | PG_error, | |
75 | PG_referenced, | |
76 | PG_uptodate, | |
77 | PG_dirty, | |
78 | PG_lru, | |
79 | PG_active, | |
80 | PG_slab, | |
81 | PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ | |
e2683181 CL |
82 | PG_arch_1, |
83 | PG_reserved, | |
84 | PG_private, /* If pagecache, has fs-private data */ | |
266cf658 | 85 | PG_private_2, /* If pagecache, has fs aux data */ |
e2683181 | 86 | PG_writeback, /* Page is under writeback */ |
e20b8cca CL |
87 | #ifdef CONFIG_PAGEFLAGS_EXTENDED |
88 | PG_head, /* A head page */ | |
89 | PG_tail, /* A tail page */ | |
90 | #else | |
e2683181 | 91 | PG_compound, /* A compound page */ |
e20b8cca | 92 | #endif |
e2683181 CL |
93 | PG_swapcache, /* Swap page: swp_entry_t in private */ |
94 | PG_mappedtodisk, /* Has blocks allocated on-disk */ | |
95 | PG_reclaim, /* To be reclaimed asap */ | |
e2683181 | 96 | PG_buddy, /* Page is free, on buddy lists */ |
b2e18538 | 97 | PG_swapbacked, /* Page is backed by RAM/swap */ |
894bc310 LS |
98 | #ifdef CONFIG_UNEVICTABLE_LRU |
99 | PG_unevictable, /* Page is "unevictable" */ | |
33925b25 DH |
100 | #endif |
101 | #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT | |
b291f000 | 102 | PG_mlocked, /* Page is vma mlocked */ |
894bc310 | 103 | #endif |
602c4d11 CL |
104 | #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR |
105 | PG_uncached, /* Page has been mapped as uncached */ | |
f886ed44 | 106 | #endif |
0cad47cf AW |
107 | __NR_PAGEFLAGS, |
108 | ||
109 | /* Filesystems */ | |
110 | PG_checked = PG_owner_priv_1, | |
111 | ||
266cf658 DH |
112 | /* Two page bits are conscripted by FS-Cache to maintain local caching |
113 | * state. These bits are set on pages belonging to the netfs's inodes | |
114 | * when those inodes are being locally cached. | |
115 | */ | |
116 | PG_fscache = PG_private_2, /* page backed by cache */ | |
117 | ||
0cad47cf AW |
118 | /* XEN */ |
119 | PG_pinned = PG_owner_priv_1, | |
120 | PG_savepinned = PG_dirty, | |
8a38082d | 121 | |
9023cb7e AW |
122 | /* SLOB */ |
123 | PG_slob_page = PG_active, | |
124 | PG_slob_free = PG_private, | |
125 | ||
8a38082d AW |
126 | /* SLUB */ |
127 | PG_slub_frozen = PG_active, | |
128 | PG_slub_debug = PG_error, | |
e2683181 | 129 | }; |
1da177e4 | 130 | |
9223b419 CL |
131 | #ifndef __GENERATING_BOUNDS_H |
132 | ||
f94a62e9 CL |
133 | /* |
134 | * Macros to create function definitions for page flags | |
135 | */ | |
136 | #define TESTPAGEFLAG(uname, lname) \ | |
137 | static inline int Page##uname(struct page *page) \ | |
138 | { return test_bit(PG_##lname, &page->flags); } | |
139 | ||
140 | #define SETPAGEFLAG(uname, lname) \ | |
141 | static inline void SetPage##uname(struct page *page) \ | |
142 | { set_bit(PG_##lname, &page->flags); } | |
143 | ||
144 | #define CLEARPAGEFLAG(uname, lname) \ | |
145 | static inline void ClearPage##uname(struct page *page) \ | |
146 | { clear_bit(PG_##lname, &page->flags); } | |
147 | ||
148 | #define __SETPAGEFLAG(uname, lname) \ | |
149 | static inline void __SetPage##uname(struct page *page) \ | |
150 | { __set_bit(PG_##lname, &page->flags); } | |
151 | ||
152 | #define __CLEARPAGEFLAG(uname, lname) \ | |
153 | static inline void __ClearPage##uname(struct page *page) \ | |
154 | { __clear_bit(PG_##lname, &page->flags); } | |
155 | ||
156 | #define TESTSETFLAG(uname, lname) \ | |
157 | static inline int TestSetPage##uname(struct page *page) \ | |
158 | { return test_and_set_bit(PG_##lname, &page->flags); } | |
159 | ||
160 | #define TESTCLEARFLAG(uname, lname) \ | |
161 | static inline int TestClearPage##uname(struct page *page) \ | |
162 | { return test_and_clear_bit(PG_##lname, &page->flags); } | |
163 | ||
164 | ||
165 | #define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ | |
166 | SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname) | |
167 | ||
168 | #define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ | |
169 | __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname) | |
170 | ||
ec7cade8 CL |
171 | #define PAGEFLAG_FALSE(uname) \ |
172 | static inline int Page##uname(struct page *page) \ | |
173 | { return 0; } | |
174 | ||
f94a62e9 CL |
175 | #define TESTSCFLAG(uname, lname) \ |
176 | TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname) | |
177 | ||
8a7a8544 LS |
178 | #define SETPAGEFLAG_NOOP(uname) \ |
179 | static inline void SetPage##uname(struct page *page) { } | |
180 | ||
181 | #define CLEARPAGEFLAG_NOOP(uname) \ | |
182 | static inline void ClearPage##uname(struct page *page) { } | |
183 | ||
184 | #define __CLEARPAGEFLAG_NOOP(uname) \ | |
185 | static inline void __ClearPage##uname(struct page *page) { } | |
186 | ||
187 | #define TESTCLEARFLAG_FALSE(uname) \ | |
188 | static inline int TestClearPage##uname(struct page *page) { return 0; } | |
189 | ||
6a1e7f77 CL |
190 | struct page; /* forward declaration */ |
191 | ||
03fb3d2a | 192 | TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked) |
6a1e7f77 CL |
193 | PAGEFLAG(Error, error) |
194 | PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) | |
195 | PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) | |
196 | PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) | |
197 | PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active) | |
894bc310 | 198 | TESTCLEARFLAG(Active, active) |
6a1e7f77 | 199 | __PAGEFLAG(Slab, slab) |
0cad47cf AW |
200 | PAGEFLAG(Checked, checked) /* Used by some filesystems */ |
201 | PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */ | |
202 | PAGEFLAG(SavePinned, savepinned); /* Xen */ | |
6a1e7f77 | 203 | PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) |
b2e18538 | 204 | PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) |
6a1e7f77 | 205 | |
9023cb7e AW |
206 | __PAGEFLAG(SlobPage, slob_page) |
207 | __PAGEFLAG(SlobFree, slob_free) | |
208 | ||
8a38082d AW |
209 | __PAGEFLAG(SlubFrozen, slub_frozen) |
210 | __PAGEFLAG(SlubDebug, slub_debug) | |
211 | ||
266cf658 DH |
212 | /* |
213 | * Private page markings that may be used by the filesystem that owns the page | |
214 | * for its own purposes. | |
215 | * - PG_private and PG_private_2 cause releasepage() and co to be invoked | |
216 | */ | |
217 | PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private) | |
218 | __CLEARPAGEFLAG(Private, private) | |
219 | PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2) | |
220 | PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1) | |
221 | ||
6a1e7f77 CL |
222 | /* |
223 | * Only test-and-set exist for PG_writeback. The unconditional operators are | |
224 | * risky: they bypass page accounting. | |
225 | */ | |
226 | TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback) | |
227 | __PAGEFLAG(Buddy, buddy) | |
228 | PAGEFLAG(MappedToDisk, mappedtodisk) | |
229 | ||
230 | /* PG_readahead is only used for file reads; PG_reclaim is only for writes */ | |
231 | PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim) | |
0a128b2b | 232 | PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */ |
6a1e7f77 CL |
233 | |
234 | #ifdef CONFIG_HIGHMEM | |
1da177e4 | 235 | /* |
6a1e7f77 CL |
236 | * Must use a macro here due to header dependency issues. page_zone() is not |
237 | * available at this point. | |
1da177e4 | 238 | */ |
0a128b2b | 239 | #define PageHighMem(__p) is_highmem(page_zone(__p)) |
6a1e7f77 | 240 | #else |
ec7cade8 | 241 | PAGEFLAG_FALSE(HighMem) |
6a1e7f77 CL |
242 | #endif |
243 | ||
244 | #ifdef CONFIG_SWAP | |
245 | PAGEFLAG(SwapCache, swapcache) | |
246 | #else | |
ec7cade8 | 247 | PAGEFLAG_FALSE(SwapCache) |
6d91add0 | 248 | SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache) |
6a1e7f77 CL |
249 | #endif |
250 | ||
894bc310 LS |
251 | #ifdef CONFIG_UNEVICTABLE_LRU |
252 | PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) | |
253 | TESTCLEARFLAG(Unevictable, unevictable) | |
33925b25 DH |
254 | #else |
255 | PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable) | |
256 | SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable) | |
257 | __CLEARPAGEFLAG_NOOP(Unevictable) | |
258 | #endif | |
b291f000 | 259 | |
33925b25 | 260 | #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT |
b291f000 NP |
261 | #define MLOCK_PAGES 1 |
262 | PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked) | |
263 | TESTSCFLAG(Mlocked, mlocked) | |
894bc310 | 264 | #else |
b291f000 NP |
265 | #define MLOCK_PAGES 0 |
266 | PAGEFLAG_FALSE(Mlocked) | |
267 | SETPAGEFLAG_NOOP(Mlocked) TESTCLEARFLAG_FALSE(Mlocked) | |
894bc310 LS |
268 | #endif |
269 | ||
602c4d11 | 270 | #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR |
6a1e7f77 | 271 | PAGEFLAG(Uncached, uncached) |
602c4d11 | 272 | #else |
ec7cade8 | 273 | PAGEFLAG_FALSE(Uncached) |
6a1e7f77 | 274 | #endif |
1da177e4 | 275 | |
0ed361de NP |
276 | static inline int PageUptodate(struct page *page) |
277 | { | |
278 | int ret = test_bit(PG_uptodate, &(page)->flags); | |
279 | ||
280 | /* | |
281 | * Must ensure that the data we read out of the page is loaded | |
282 | * _after_ we've loaded page->flags to check for PageUptodate. | |
283 | * We can skip the barrier if the page is not uptodate, because | |
284 | * we wouldn't be reading anything from it. | |
285 | * | |
286 | * See SetPageUptodate() for the other side of the story. | |
287 | */ | |
288 | if (ret) | |
289 | smp_rmb(); | |
290 | ||
291 | return ret; | |
292 | } | |
293 | ||
294 | static inline void __SetPageUptodate(struct page *page) | |
295 | { | |
296 | smp_wmb(); | |
297 | __set_bit(PG_uptodate, &(page)->flags); | |
0ed361de NP |
298 | } |
299 | ||
2dcea57a HC |
300 | static inline void SetPageUptodate(struct page *page) |
301 | { | |
0ed361de | 302 | #ifdef CONFIG_S390 |
2dcea57a | 303 | if (!test_and_set_bit(PG_uptodate, &page->flags)) |
6c210482 | 304 | page_clear_dirty(page); |
f6ac2354 | 305 | #else |
0ed361de NP |
306 | /* |
307 | * Memory barrier must be issued before setting the PG_uptodate bit, | |
308 | * so that all previous stores issued in order to bring the page | |
309 | * uptodate are actually visible before PageUptodate becomes true. | |
310 | * | |
311 | * s390 doesn't need an explicit smp_wmb here because the test and | |
312 | * set bit already provides full barriers. | |
313 | */ | |
314 | smp_wmb(); | |
315 | set_bit(PG_uptodate, &(page)->flags); | |
1da177e4 | 316 | #endif |
0ed361de NP |
317 | } |
318 | ||
6a1e7f77 | 319 | CLEARPAGEFLAG(Uptodate, uptodate) |
1da177e4 | 320 | |
6a1e7f77 | 321 | extern void cancel_dirty_page(struct page *page, unsigned int account_size); |
d77c2d7c | 322 | |
6a1e7f77 CL |
323 | int test_clear_page_writeback(struct page *page); |
324 | int test_set_page_writeback(struct page *page); | |
1da177e4 | 325 | |
6a1e7f77 CL |
326 | static inline void set_page_writeback(struct page *page) |
327 | { | |
328 | test_set_page_writeback(page); | |
329 | } | |
1da177e4 | 330 | |
e20b8cca CL |
331 | #ifdef CONFIG_PAGEFLAGS_EXTENDED |
332 | /* | |
333 | * System with lots of page flags available. This allows separate | |
334 | * flags for PageHead() and PageTail() checks of compound pages so that bit | |
335 | * tests can be used in performance sensitive paths. PageCompound is | |
336 | * generally not used in hot code paths. | |
337 | */ | |
338 | __PAGEFLAG(Head, head) | |
339 | __PAGEFLAG(Tail, tail) | |
340 | ||
341 | static inline int PageCompound(struct page *page) | |
342 | { | |
343 | return page->flags & ((1L << PG_head) | (1L << PG_tail)); | |
344 | ||
345 | } | |
346 | #else | |
347 | /* | |
348 | * Reduce page flag use as much as possible by overlapping | |
349 | * compound page flags with the flags used for page cache pages. Possible | |
350 | * because PageCompound is always set for compound pages and not for | |
351 | * pages on the LRU and/or pagecache. | |
352 | */ | |
6a1e7f77 CL |
353 | TESTPAGEFLAG(Compound, compound) |
354 | __PAGEFLAG(Head, compound) | |
1da177e4 | 355 | |
d85f3385 | 356 | /* |
6d777953 | 357 | * PG_reclaim is used in combination with PG_compound to mark the |
6a1e7f77 CL |
358 | * head and tail of a compound page. This saves one page flag |
359 | * but makes it impossible to use compound pages for the page cache. | |
360 | * The PG_reclaim bit would have to be used for reclaim or readahead | |
361 | * if compound pages enter the page cache. | |
6d777953 CL |
362 | * |
363 | * PG_compound & PG_reclaim => Tail page | |
364 | * PG_compound & ~PG_reclaim => Head page | |
d85f3385 | 365 | */ |
6d777953 CL |
366 | #define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) |
367 | ||
6a1e7f77 CL |
368 | static inline int PageTail(struct page *page) |
369 | { | |
370 | return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask); | |
371 | } | |
6d777953 CL |
372 | |
373 | static inline void __SetPageTail(struct page *page) | |
374 | { | |
375 | page->flags |= PG_head_tail_mask; | |
376 | } | |
377 | ||
378 | static inline void __ClearPageTail(struct page *page) | |
379 | { | |
380 | page->flags &= ~PG_head_tail_mask; | |
381 | } | |
382 | ||
e20b8cca | 383 | #endif /* !PAGEFLAGS_EXTENDED */ |
dfa7e20c | 384 | |
894bc310 | 385 | #ifdef CONFIG_UNEVICTABLE_LRU |
b291f000 | 386 | #define __PG_UNEVICTABLE (1 << PG_unevictable) |
894bc310 | 387 | #else |
b291f000 | 388 | #define __PG_UNEVICTABLE 0 |
33925b25 DH |
389 | #endif |
390 | ||
391 | #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT | |
392 | #define __PG_MLOCKED (1 << PG_mlocked) | |
393 | #else | |
b291f000 | 394 | #define __PG_MLOCKED 0 |
894bc310 LS |
395 | #endif |
396 | ||
dfa7e20c RA |
397 | /* |
398 | * Flags checked when a page is freed. Pages being freed should not have | |
399 | * these flags set. It they are, there is a problem. | |
400 | */ | |
79f4b7bf | 401 | #define PAGE_FLAGS_CHECK_AT_FREE \ |
266cf658 DH |
402 | (1 << PG_lru | 1 << PG_locked | \ |
403 | 1 << PG_private | 1 << PG_private_2 | \ | |
404 | 1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \ | |
405 | 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ | |
79f4b7bf | 406 | __PG_UNEVICTABLE | __PG_MLOCKED) |
dfa7e20c RA |
407 | |
408 | /* | |
409 | * Flags checked when a page is prepped for return by the page allocator. | |
79f4b7bf HD |
410 | * Pages being prepped should not have any flags set. It they are set, |
411 | * there has been a kernel bug or struct page corruption. | |
dfa7e20c | 412 | */ |
79f4b7bf | 413 | #define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1) |
dfa7e20c | 414 | |
9223b419 | 415 | #endif /* !__GENERATING_BOUNDS_H */ |
266cf658 DH |
416 | |
417 | /** | |
418 | * page_has_private - Determine if page has private stuff | |
419 | * @page: The page to be checked | |
420 | * | |
421 | * Determine if a page has private stuff, indicating that release routines | |
422 | * should be invoked upon it. | |
423 | */ | |
424 | #define page_has_private(page) \ | |
425 | ((page)->flags & ((1 << PG_private) | \ | |
426 | (1 << PG_private_2))) | |
427 | ||
1da177e4 | 428 | #endif /* PAGE_FLAGS_H */ |